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1.
Diurnal water storage in the stems of Picea sitchensis (Bong.) Carr.   总被引:1,自引:1,他引:0  
Abstract. Two models of the relationship between diurnal variation in shoot water potential and transpiration in 14-year-old Picea sitchensis (Bong.) Carr. were compared. The first model was a physiologically based resistance-capacitance (R-C) analogue with its associated differential equations. The second was a non-physiological discrete-difference (D-D) or stochastic transfer function model. The RC model included only the effect of water storage in the phloem and bark while the D-D model implicity included all storage mechanisms. The R-C and D-D models explained similar fractions (62% and 68% respectively) of the variation in shoot water potential due to diurnal changes in transpiration rate. However, the D-D model had fewer parameters than the R-C model. The results from the D-D model showed that the resistance to flow from soil to shoots along the trunk, (RT), was 5 × 103 MPa kg-1s and the capacitance of the phloem and bark treated as a single store, (Cs), was 1.6 kg MPa-1. It is suggested that the resistance to flow into storage (Rs) is much greater than RT and can be disregarded. A non-linear version of the D-D model suggested [hat resistance to flow in the trunk increases with increasing transpiration rate.  相似文献   

2.
Summary The distribution of gap junctions in zebra fish embryo is a dynamic process. They appear during cleavage stages and are uniformly distributed between deep cells in early blastula. By mid-blastula stage their density increases all over the embryo. At this stage lightly stained L cells and densely stained D cells (Dasgupta and Singh 1981; Wilhelm Roux's Arch Dev Biol 190:358) develop some differences in their surface properties due to which the frequencies of gap junctions between homologous (L-L and D-D) cells are two- to threefold higher than between heterologous (L-D) cells. Before the initiation of epipoly the gap junction occurrence increases in the envelopinglayer (EVL) and then decreases. The possible functional significance of the organization of these junctions is discussed.  相似文献   

3.
The asymmetric reduction of benzyl to (S)-benzoin with Penicillium claviforme IAM 7294 was applied to a liquid-liquid interface bioreactor (L-L IBR) using a unique polymeric material, ballooned microsphere (MS). The L-L IBR showed superior performance, as compared with suspension, organic-aqueous two-liquid-phase, and solid-liquid interface bioreactor (S-L IBR) systems, affording 14.4 g/l-organic phase of (S)-benzoin (99.0% ee).  相似文献   

4.
The asymmetric reduction of benzyl to (S)-benzoin with Penicillium claviforme IAM 7294 was applied to a liquid-liquid interface bioreactor (L-L IBR) using a unique polymeric material, ballooned microsphere (MS). The L-L IBR showed superior performance, as compared with suspension, organic-aqueous two-liquid-phase, and solid-liquid interface bioreactor (S-L IBR) systems, affording 14.4 g/l-organic phase of (S)-benzoin (99.0% ee).  相似文献   

5.
This study was undertaken to validate the potential of 31P magnetic resonance spectroscopy (MRS) as a noninvasive alternative for transvenous endomyocardial biopsy in detecting cardiac allograft rejection. Donor hearts from either Lewis rats (L) or Brown-Norway rats (BN) were transplanted into the neck of L rats resulting in a non-rejecting group L-L and a rejecting group L-BN. L-L and L-BN rats were serially studied by means of 31P MRS from postoperatine day 1–8. In addition, rejection was confirmed by histology. A similar, marked decrease in phosphocreative/-adenosinetriphosphate (PCr/ATP) ratio from day 1–3 was observed in both L-L and L-BN hearts. This ratio levelled off on postoperative day 3 and remained depressed on subsequent postoperative days in both groups, although histology showed an increase in the severity of rejection in L-BN. However, the PCr signal/noise ratio in L-BN started to decrease after day 4, coinciding with the histologic evidence of severe rejection (score IV), whereas in L-L hearts (score 0) this ratio remained unaltered until day 8. Since high-energy phosphate metabolism is affected by the unloaded status of the heterotopically transplanted heart, irrespective of rejection, the PCr/ATP ratio appears not to be a specific marker for the detection of acute rejection in this model. In contrast, the PCr S/N ratio appears to be a specific and sensitive marker of acute rejection, but only in a late, severe stage.  相似文献   

6.
摘要 目的:探讨血清D-二聚体(D-D)、尿素氮与肌酐比值(UCR)联合C反应蛋白与白蛋白比值(CAR)对重症肺炎(SP)患者院内死亡的评估价值。方法:选取2019年6月~2022年6月我院收治的101例SP患者,根据是否发生院内死亡分为死亡组和存活组。检测血清D-D和计算UCR、CAR。分析SP患者院内死亡的影响因素,受试者工作特征(ROC)曲线分析血清D-D、UCR、CAR对SP患者院内死亡的评估价值。结果:101例SP患者院内死亡率40.59%(41/101)。死亡组血清D-D、UCR、CAR高于存活组(P均<0.05)。多因素Logistic回归分析显示,年龄增加、肺外并发症≥2个和D-D、UCR、CAR升高为SP患者院内死亡的独立危险因素(P均<0.05)。ROC曲线分析显示,血清D-D、UCR、CAR单独与联合评估SP患者院内死亡的曲线下面积分别为0.781、0.798、0.793、0.929,血清D-D、UCR联合CAR评估SP患者院内死亡的AUC大于各指标单独评估。结论:血清D-D、UCR、CAR升高为SP患者院内死亡的独立危险因素,D-D、UCR联合CAR对SP患者院内死亡的评估价值较高。  相似文献   

7.
Large amounts of dazomet (329, 439 kg/ha) applied to potato ridge soil in spring, before potatoes were planted, controlled potato cyst-nematode (Heterodera rostochiensis) in sandy loam and silt loam more effectively than large amounts of D-D (359, 448 kg/ha). In heavily infested sandy loam, 329 kg dazomet/ha or 857 kg methyl bromide/ha applied in spring 1969 or 439 kg dazomet/ha applied in autumn 1968, greatly decreased the number of larvae able to invade potato roots, so Majestic potatoes grew and yielded well without increasing the number of nematodes left in the soil after harvest. Large amounts of D-D or Telone applied to the topsoil in autumn or to the ridges in spring were less effective in controlling potato cyst-nematode or increasing potato yields. Applied in spring 1969 to silt loam ridges, 439 kg dazomet/ha had more effect than 448 kg D-D/ha on potato cyst-nematode and on the increase in yield of Majestic potato. The yield of Maris Piper potatoes (resistant to H. rostochiensis pathotype A) in infested silt loam was increased greatly by D-D, as much by 112 as by 224 or 448 kg/ha.  相似文献   

8.
A Fujimura  K Ohashi  A Ebihara 《Life sciences》1990,47(18):1641-1646
We have previously reported that a time-dependent variability is observed in the diuretic effects of furosemide in rats. The present study was undertaken to examine the influence of prolonged exposure to continuous light on chronopharmacological profiles of furosemide in Wistar rats. In study I, rats were maintained for more than 2 weeks under conditions of light (0700-1900 hrs) and dark (1900-0700 hrs) (L-D). Furosemide (30 mg/kg) was orally given at 1200 hrs or at 2400 hrs. Urine was collected for 8 hours after the drug and urinary excretion of sodium and furosemide were determined respectively. Thereafter, these rats were exposed to continuous light (L-L) for the next 4 weeks, and were again maintained under the L-D cycle. The identical trial of study I was repeated at the end of the L-L (study II) and the second L-D (study III) conditions. Urine volume and urinary excretion of sodium and furosemide following the drug were significantly greater at 1200 hrs than at 2400 hrs under conditions of L-D (study I and III). However these administration time-dependent changes in the effects of furosemide and its urinary amount disappeared with L-L condition (study II). These findings indicate that the mode of the time-dependent changes in the effects of furosemide is altered by prolonged exposure to continuous light.  相似文献   

9.
Compounds of the types ReOCl3(L-L) and ReOCl2(OEt)(L-L) with bis(diphenylphosphino)ethene (dppen) and bis(diphenylphosphino)ferrocene (dppf) were prepared by reacting the diphosphine with ReOCl3(OPPh3)(Me2S). The ReOCl3(L-L) compound with bis(diphenylarsino)ethane (dpae) was prepared similarly. Crystallographic work on ReOCl3(dppen) and ReOCl3(dpae) confirmed the approximate octahedral environment of the metal and the presence of a Cl ligand trans to the ReO bond. The ReOCl2(OEt)(L-L) compounds contain a transORe-OEt unit. The visible spectra of both types of compounds include a two-component d-d absorption pattern originating from the spin-allowed excitation of a d electron from the interaxial d orbital in the equatorial plane to the empty dxz and dyz orbitals. For ReOCl2(OEt)(dppf), these bands are masked by strong transitions taking place in the ferrocene moiety. The absorptions of the other systems are not greatly displaced compared to the similar dppe compounds, a small decrease in the transition energy being noted for the dpae complex.  相似文献   

10.
The optimal amounts of 1-hydroxybenzotriazole (HOBt), 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine (HOOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) for enhancement of peptide coupling mediated by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) hydrochloride in alcoholic solvents were found to be less than equimolar against the carboxyl component or the carbodiimide. In comparison with the use of equimolar additives, the use of less equimolar ones was more effective in suppressing the competitive ester formation and in increasing the yield of desired peptides. EDC hydrochloride/around 0.1 equimolar HOAt or HOOBt were efficient reagents for peptide synthesis in the media.  相似文献   

11.
目的:探究慢性阻塞性肺疾病急性加重期(AECOPD)患者血清降钙素原(PCT)、超敏C反应蛋白(hs-CRP)、D-二聚体(D-D)和纤维蛋白原(FIB)与肺功能和预后的关系。方法:选择2017年8月至2019年8月期间我院诊治的88例AECOPD患者作为观察组,根据患者生存情况将患者进一步分为85例存活组和3例死亡组。同时选择同期在我院进行健康体检的50名志愿者作为对照组。检测各组患者的血清PCT、hs-CRP、D-D和FIB水平,采用肺功能检测仪检测第一秒用力呼气容积(FEV1)%、第一秒用力呼气容积占用力肺活量比值(FEV1/FVC)和最大通气量(MVV)肺功能指标,采用Pearson相关性分析进行各指标的相关性分析。结果:与对照组相比,观察组的血清PCT、hs-CRP、D-D和FIB水平均明显升高(P0.05)。与存活组相比,死亡组的血清PCT、hs-CRP、D-D和FIB水平均明显升高(P0.05),FEV1%、FEV1/FVC和MVV指标均明显下降(P0.05)。Pearson相关性分析显示,血清PCT、hs-CRP、D-D和FIB水平均与FEV1%、FEV1/FVC和MVV肺功能指标呈负相关(P0.05)。结论:AECOPD患者肺功能下降和不良预后与血清PCT、hs-CRP、D-D和FIB水平升高密切相关,在AECOPD患者的预后预测中具有一定临床价值。  相似文献   

12.
An artificial substrate was developed for quantitative testing of the ability of various fixatives to preserve the reactivity of IgG and IgA isotypes (gamma and alpha chains) and the secretory component (SC) of secretory IgA as model antigens. Polymerized normal rabbit serum was used as matrix and defined amounts (10-0.1 g/l) of antigen were incorporated into it by diffusion before fixation and paraffin embedding. The various fixatives comprised alcohol, routine formalin, glutaraldehyde(1%)-formalin, Baker's formol calcium, formol sublimate, acetic acid(2%)-formol saline, Bouin's fluid, Susa fixative, and carbodiimide. The detection sensitivity afforded by these fixatives was defined as the immunofluorescence staining end point. Compared to the reference value obtained with alcohol (gamma and alpha chains, 0.06 g/l of IgG and IgA; SC, 0.12 g/l of colostral IgA), an antigen concentration at least 8 times higher was necessary for detection with most of the cross-linking fixatives. Bouin's and Susa fixatives were peculiar in that they required more than 150 times higher antigen concentration for detection of IgG but only 3-8 times higher for IgA. The determined sensitivities were compared with the immunofluorescence performance results obtained on human tissues prepared with the same fixatives; excepting carbodiimide (which produced unacceptable autofluorescence of the substrate matrix) a remarkably good correlation was found with regard to IgG- and IgA-producing cells (especially of the former isotype) and secretory epithelium (IgA and SC). However, the latter result depended on pronase treatment of the tissue sections to unmask epithelial antigens.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
目的:探讨高凝状态对非小细胞肺癌患者深静脉血栓形成的影响,为临床治疗提供依据。方法:选择2010年5月至2013年6月在我院接受治疗的非小细胞肺癌患者195例,记录患者姓名、年龄、性别、病理类型、手术、临床分期、放化疗、伴随疾病、身体状况评分(eastern cooperative oncology group,ECOG评分)及是否发生血栓等指标。调查入选患者的高凝状态指标,包括血小板(platelet,PLT)、纤维蛋白原(fibrinogen,Fib)、血浆凝血酶原时间(plasma prothrombin time,PT)、凝血酶时间(thrombin time,TT)、活化部分凝血活酶时间(activated coagulation time of whole blood,APTT)和D-二聚体(D-dimer)。结果:195例非小细胞肺癌患者中,PLT高于正常上限的有42例(21.5%),FIB升高的有78例(40%),TT延长的有12例(6.2%),PT缩短的有45例(23.1%),D-D升高的有60例(30.8%),APTT缩短的有15例(7.7%)。两项指标异常的有62例(31.8%),FIB和D-D升高的有32例(16.4%);三项指标异常的有27例(13.8%),PLT、FIB及D-D升高的有15例(7.7%);四项指标异常的有5例(2.6%),PLT、FIB及D-D升高,而PT缩短的有5例(2.6%)。所有患者各凝血指标中位值PLT为219×109/L,FIB为3.6 g/L,TT为13.4 s,PT为10.8 s,D-D为0.341 mg/L,APTT为29.7 s。结论:高凝状态对非小细胞肺癌患者深静脉血栓形成具有重要的促进作用,应受到临床的重视。  相似文献   

14.
Square planar Ni(II), Pd(II) and Pt(II) complexes of the para-methoxy derivatised analogue of dppe, 1,2-bis{di-(4-methoxyphenyl)phosphino}ethane (L-L), [MCl2(L-L)] and [M(L-L)2]Cl2 (M = Ni, Pd, Pt) are readily prepared, and have been characterised by elemental analysis, IR and NMR spectroscopies. The structures of [NiCl2(L-L)] and [PdCl2(L-L)] have been determined by single-crystal X-ray diffraction.  相似文献   

15.
摘要 目的:探讨肾病综合征(NS)患者血清同型半胱氨酸(Hcy)、D-二聚体(D-D)和B型钠尿肽(BNP)水平及与发生血栓栓塞(TE)的关系。方法:选取2017年1月~2019年1月我院收治的241例NS患者,根据是否并发TE分为TE组56例,非TE组185例,另选取65名体检健康者为对照组,对比各组血清Hcy、D-D和BNP水平,多因素Logistics回归分析NS患者并发TE的影响因素,ROC曲线判断血清Hcy、D-D和BNP水平对NS患者并发TE的诊断价值。结果:三组血清Hcy、D-D和BNP水平比较差异有统计学意义(P<0.05)。TE组血清Hcy、D-D和BNP水平明显高于非TE组,非TE组血清Hcy、D-D和BNP水平明显高于对照组,差异均有统计学意义(P<0.05)。TE组高血压史、利尿剂使用史、糖皮质激使用史比例和BUN、24hUPQ水平明显高于非TE组,差异均有统计学意义(P<0.05)。多因素Logistics回归分析显示,Hcy、D-D、BNP、24hUPQ为NS患者并发TE独立影响因素(P<0.05)。ROC曲线显示,血清Hcy+D-D+BNP水平诊断NS患者并发TE的AUC明显大于血清Hcy、D-D和BNP单独诊断,敏感度和特异度也高于各指标单独诊断。结论:NS患者血清Hcy、D-D和BNP水平明显提升,合并TE后进一步提高,且血清Hcy、D-D和BNP水平为NS患者发生TE的危险因素,联合测定可提高诊断价值。  相似文献   

16.
Particulate aluminum oxides (alumina) were examined as supports for the immobilization of the proteolytic enzyme papain. Two alumina supports termed C1 and CPC were derivatized using organic phosphate linkers to create free carboxyl groups using a two-step process. Papain binding to these derivatized aluminas was performed using the water soluble carbodiimide 1-ethyl-3-(dimethylaminopropyl) carbodiimide. Reactions were optimal at 10 mM carbodiimide. The immobilized protein showed similar kinetic constants when compared to the solution protein. The pH dependence and thermal stability were essentially identical. The immobilized papain showed a blue shift in the intrinsic fluorescence emission maxima. Papain modified with the active site-specific fluorescent probe acrylodan showed overlapping emission maxima. These results are interpreted as retention of the hydrophobic environment of the active site with a perturbation in the structure of the rest of the protein caused by its association with the negatively charged surface. (c) 1992 John Wiley & Sons, Inc.  相似文献   

17.
A novel and effective treatment of biological samples with a combination of adenosine phosphate deaminase and apyrase was developed for reducing extracellular ATP, which has been a major problem encountered in improving the sensitivity of assays for intracellular ATP by the firefly luciferin–luciferase (L-L) method. Under the enzymatic reaction conditions, ATP and the related adenosine derivatives were converted to IMP, which are not active to the L-L system. In the model system (3.2 × 10−8mATP in 1% yeast extract solution) the treatment with adenosine phosphate deaminase resulted in the reduction of ATP to 1.3 × 10−11m, and the concomitant use of apyrase lowered the concentration to 3.3 × 10−13m. The treatment (0.05 U/ml of adenosine phosphate deaminase and apyrase) was applied to the detection of bacteria in broth by the L-L method, affording the detection of 42 colony-forming unit (CFU)/ml ofEscherichia coliand 10 CFU/ml ofStaphylococcus aureusin the broth.  相似文献   

18.
We report the synthesis of phosphorescent divalent osmium complexes of the form [Os(N-N)2(L-L) or Os(L-L)2(N-N)]2+ (PF6)2 where N-N is a derivative of 1,10-phenanthroline, and L-L is a diarsine or diphosphine ligand: 1,2-bis(dimethylphosphino)ethane, 1,2-bis(dicyclohexylphosphino)ethane, or 1,2-bis(dimethylarseno)benzene. X-ray structures have been determined, luminescent and electrochemical properties have been measured and DFT calculations have been performed on the complexes. The emission lifetime of complexes of structure Os(II)(L-L)2(N-N) are longer than the those of Os(II)(N-N)2(L-L). The DFT calculations show that there is significant mixing of the π−π into the dπ−π charge-transfer state for the complexes of the form Os(II)(L-L)2(N-N) resulting in a longer lived excited state. Through DFT calculations we were able to conclude that the HOMO of the complexes is a d orbital on the osmium while the LUMO is the b1(ψ) π system of the phenanthroline. However, we found that the HOMO did not have the correct symmetry to enable strong charge transfer to the phenanthroline to be observed, and the strong MLCT transition observed in the spectra is the metal d HOMO(−1) to the b1 π LUMO of the phenanthroline.  相似文献   

19.
Photosystem I from the cyanobacterium Synechocystis sp. PCC 6803 was examined using the chemical cross-linkers glutaraldehyde and N-ethyl-1-3-[3-(dimethylamino)propyl]carbodiimide to investigate the organization of the polypeptide subunits. Thylakoid membranes and photosystem I, which was isolated by Triton X-100 fractionation, were treated with cross-linking reagents and were resolved using a Tricine/urea low-molecular-weight resolution gel system. Subunit-specific antibodies and western blotting analysis were used to identify the components of cross-linked species. These analyses identified glutaraldehyde-dependent cross-linking products composed of small amounts of PsaD and PsaC, PsaC and PsaE, and PsaE and PsaF. The novel cross-link between PsaE and PsaF was also observed following treatment with N-ethyl-1-3-[3-(dimethylamino)propyl]carbodiimide. These cross-linking results suggest a structural interaction between PsaE and PsaF and predict a transmembrane topology for PsaF.  相似文献   

20.
目的:探讨腰硬联合麻醉(CSEA)对剖宫产围术期患者围术期皮质醇及血浆D-二聚体(D-D)水平变化的影响。方法:选取2014年3月-2015年5月在我院接受剖宫产手术的患者68例为研究对象。.根据术中采用的麻醉方法不同,将患者分为腰硬联合麻醉组(CSEA组)和连续硬膜外麻醉组(CEA组)。观察并比较两组患者围手术期皮质醇及D-二聚体水平的变化情况。结果:两组患者术中纤维蛋白原、凝血活酶时间及凝血酶原时间间比较,差异均无统计学意义(P0.05);两组患者麻醉后皮质醇及D-D水平均显著高于麻醉前,但CSEA组低于CEA组,差异具有统计学意义(P0.05);两组患者D-D水平在手术结束时、术后24 h较麻醉前均显著升高,差异有统计学意义(P0.05);但CSEA组D-D水平在术后24 h及、术后72 h,CSEA组D-D水平均低于CEA组,差异具有统计学意义(P0.05)。结论:腰硬联合麻醉可以更好的抑制剖宫产患者术中血清皮质醇及术后血浆D-D水平的升高,有利于改善患者术后高凝状态,值得临床推广应用。  相似文献   

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