草酸钙结石患者尿液中纳米级和微米级晶体研究

尿液中存在的微晶与尿石症的形成密切相关。采用X射线粉末衍射(XRD)、傅里叶变换红外光谱(FTIR)、纳米粒度仪、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了20位草酸钙结石患者尿液中纳米级和微米级晶体的组分、形貌和Zeta电位,并与结石组分进行了比较。结果表明,草酸钙结石中常常含有少量共生的尿酸、磷酸钙和磷酸铵镁;而草酸钙结石患者的尿微晶组分主要为尿酸、磷酸盐和草酸钙等,晶体棱角尖锐,尺寸不一,从几十纳米到几十微米不等,并且有明显的团聚现象。20位草酸钙结石患者的尿纳米晶体的Zeta电位平均值为-5.92 mV,明显高于20位健康对照者尿纳米晶体的Zeta电位(平均值-12.9 mV);相比之下,结石患者尿液pH值(平均值为6.03)则与健康对照者(平均值5.92)没有明显差异。利用现代仪器分析方法分析尿液微晶与尿石组分的关系,可为临床上对症下药,制定预防与治疗措施提供重要的依据。     

尿酸结石患者尿液中的微晶组分及其与结石形成的关系

采用X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、纳米粒度仪、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了10例尿酸结石患者尿微晶的组分、Zeta电位、形貌及其与尿酸结石形成的关系.结果表明,尿酸结石患者的尿pH值较低,大都在4.8～5.7之间;尿微晶的主要成分为尿酸.其粒度分布很不均匀,从几纳米到几十微米不等,并有聚集现象.相比健康对照者尿纳米微品的Zeta电位(-10.1mV),尿酸结石患者的Zeta电位负值更小(-6.02 mV).对这些患者进行药物治疗(服用柠檬酸钾)后,尿pH可上升到6.5左右,此时尿液中的大部分尿酸转变为溶解度显著增加的尿酸盐,因此,尿酸结石形成的危险性显著降低.本文结果表明,尿石组分、尿微晶组分及尿pH三者之间存在密切的联系.     

尿液中的纳米晶体组分及其对草酸钙结石形成的影响

采用高分辨率透射电子显微镜、选区电子衍射、能谱分析和X射线衍射对草酸钙(CaOx)结石患者尿液中纳米晶体的组分进行了准确分析。这些技术检测到一水草酸钙(COM)、尿酸(UA)和磷酸钙(CaP)的存在,能谱分析检测到大量C,O,Ca和少量N和P等元素,表明尿纳米晶体的主要组分是COM,并含有少量的尿酸和磷酸盐。电子显微镜观察到CaOx结石患者尿纳米晶体的粒径主要分布在几十纳米,其结果与Scherer公式计算相符。采用不同孔径的微孔滤膜(0.45,1.2和3 μm)将尿液过滤后,得到的尿微晶衍射峰的数量随着滤膜孔径的增加而增加,表明尿微晶的种类增加。CaOx尿石的形成过程涉及尿液晶体的成核、生长、团聚和与细胞的粘附等过程。尿液中大量纳米COM晶体的存在是草酸钙结石形成的重要原因。纳米UA,CaP晶体能够作为晶巢促进草酸钙结石的形成。     

磷酸铵镁结石患者尿微晶组分分析及其与结石形成的关系

采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、纳米粒度仪、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了磷酸铵镁结石患者尿液中微晶的组分、形貌、粒径和Zeta电位,并对其结石进行了组分分析.结果表明,结石类型、尿微晶组分和尿液pH三者之间存在密切的联系:磷酸铵镁结石病人的尿液pH值较高,通常在6....     

不同形貌二水草酸钙对阴离子表面活性剂AOT的吸附差异

人体尿液中存在大量具有生物表面活性的物质,而这些物质与尿液中不同形貌的草酸钙微晶间的吸附关系并未得到人们广泛关注。挑选了常用的阴离子表面活性剂磺基琥珀酸钠二辛酯(AOT)作为吸附物质,研究了不同形貌的二水草酸钙(COD)晶体对AOT的吸附差异,探究草酸钙结石的形成机理。采用X射线粉末衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR)表征,并通过谱图差异分析了吸附AOT前后棒状、圆钝形、花状、十字形和双锥形COD晶体的组分变化;采用Zeta电位分析仪测定吸附AOT后晶体表面的Zeta电位随AOT浓度的变化;采用比色法通过紫外可见分光光度计测定不同浓度AOT存在下晶体的吸附量变化并绘制吸附曲线。随着AOT浓度的增加,COD的吸附量逐渐上升,最后达到吸附饱和状态,各吸附曲线均呈S型。不同形貌COD对AOT的最大吸附量大小顺序为：棒状COD (41.0 mg·g-1)>圆钝形COD (37.5 mg·g-1)>花状COD (35.0 mg·g-1)>十字形COD (27.2 mg·g-1)>双锥形COD (20.9 mg·g-1)。COD晶体的比表面积越大,表面提供的活性位点也越多,越有利于表面活性剂AOT在晶体表面的吸附;富含Ca2+的(100)晶面更利于阴离子的AOT的优先吸附;此外COD晶体的内能越大,越会抑制AOT在COD表面的吸附,导致吸附量降低。吸附了AOT的COD晶体稳定性显著增加,COD向COM转变的速度明显降低。基于AOT在不同形貌的COD晶体表面的吸附特点,提出了COD晶体吸附AOT的分子模型。COD晶体对AOT的吸附与晶体形貌密切相关。容易吸附AOT的COD晶体形貌更容易粘附在带负电荷受损伤的细胞表面,加大草酸钙结石形成的风险。     

掺Er~(3+)的氟氧化物微晶玻璃上转换及近红外光谱性质

研究了组份为46SiO2-46PbF2-5Al2O3-3ZnF2(mol%),外掺4ErF3(mol%)的氟氧化物玻璃样品在微晶化前后的性能。根据样品的DTA曲线分析了其热稳定性,测试了微晶化前后Er3+的吸收光谱、上转换及近红外荧光光谱,根据样品的XRD图谱对比得到了其微晶相PbF2。结合能级图和荧光光谱分析了微晶化对光谱性质的影响。研究表明,微晶化后上转换荧光强度得到了极大的提高,特别对667nm的红光,其作用更为明显,微晶化对1.5μm荧光的有效半高宽几乎没有影响,但却极大地削减了峰值发射截面,显著地减小了Δλeff×eδ。     

白光LED用LiYF_4∶Pr~(3+)微晶玻璃的发光性能研究

采用高温熔融法制得组分为43SiO_2-23Al_2O_3-27LiF-17YF_3-xPr_2O_3(x=0.05、0.1、0.15、0.2)(mol%)的前驱玻璃.玻璃样品分别经530℃、540℃和550℃热处理后,制备出一系列Pr~(3+)离子掺杂含LiYF4晶粒的微晶玻璃.晶相由X射线衍射与透射电子显微镜证实,晶粒平均尺寸为14±4nm.紫外-可见分光光度计证实微晶玻璃具有良好的透光性.研究热处理前后样品的光谱特性和荧光寿命,对封装成LED后的相关参数进行测试.结果表明,在波长444nm的激发下,掺杂Pr~(3+)离子浓度为0.3mol且热处理温度为550℃的微晶玻璃具有最高光输出强度,封装成LED后发射出白光,其色坐标为x=0.33,y=0.35.     

弱激光诱导神经元兴奋性改变的实验研究

利用全细胞膜片钳技术研究弱激光诱导下大鼠海马CA3区锥体神经元兴奋性.实验结果显示：弱激光作用使神经元钠通道激活电位向超极化方向移动,钠电流幅度增大,且这种增大作用具有电压依赖性和可逆性.激光作用显著影响钠电流稳态激活与失活特性,对照组和照射组通道半数激活电压分别为(-4414±528)mV和(-5655±614)mV(n=8,P<001),半数失活电压分别为(-6902±1031)mV和(-5660±897)mV(n=8, P<0 关键词： 钠离子通道 膜片钳技术 弱激光 动作电位 神经元     

纳米ZnO微晶的合成及其发光特性

以醋酸锌和尿素为主要原料,利用沉淀-水热法一步合成了纳米ZnO微晶。用XRD,TEM,FTIR等测试技术及光致发光光谱(PL)对纳米ZnO微晶进行了表征,并对其发光特性进行了分析。研究表明：该合成方法操作简单,得到的纳米ZnO颗粒基本无团聚,结晶性较好,平均粒径约为17.2 nm,并在500～750 nm范围内出现宽的PL峰, 呈现出纳米材料的发光特征。     

AlN微晶棒的的制备及光致发光性能研究

采用直流电弧放电方法,在无催化剂的条件下直接氮化Al合成纤锌矿结构的AlN微晶棒。分别利用拉曼光谱仪(Raman)、扫描电子显微镜(SEM)和光致发光(PL)谱等测试手段对所制备样品进行表征和发光性能的研究。结果表明:所制备的Al N微晶棒长度约为30μm,直径约为10μm。在AlN微晶棒的PL谱中,有两个主要发光峰,中心在430 nm的发射源于VN和(V_(Al)-O_N)~(2-)构成的深施主-深受主对缺陷发光,中心在650 nm的发射源于VAl形成的深受主能级到价带的缺陷发光。在激发波长由270 nm逐渐增大到300 nm的过程中发现,Al N微晶棒波长在430 nm处的发光峰先增强后减弱,在激发波长为285 nm时强度最大;650 nm处的发光峰随激发波长增大而逐渐增强。     

Micro‐Raman spectroscopy identification of urinary stone composition from ureteroscopic lithotripsy urine powder

Urolithiasis is a prevalent, disturbing, and highly recurrent disease. Knowing the composition of a urinary stone is important for prevention purposes. Traditional urinary stone analysis methods need large stone fragments for analysis. However, the advancement of ureteroscopic lithotripsy (URSL) has resulted in micro‐stone fragments and unapparently expelled urinary stone powder. In this study, we developed a micro‐Raman spectroscopy (MRS) based diagnosis method for detecting micro‐stones or stone powders in urine after URSL. In our experiment, urine samples of 10 ml each were collected from 12 patients over the fragmented stone site in the ureter after the URSL procedure. The post‐URSL urine sediments extracted from urine were analyzed by MRS. The small urinary stones caught by grasping forceps were analyzed by both MRS and Fourier‐transform infrared (FTIR) spectroscopy. We have identified common urinary stone compositions: calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD), dicalcium phosphate dihydrate (DCPD), calcium phosphate hydroxide (hydroxyl apatite or HAP), and uric acid, by using a 632.8 nm He‐Ne laser for excitation, a 100× microscope objective lens for irradiation and collection, and a short photobleaching time for fluorescent background reduction. Thus, we developed an MRS‐based method for analyzing the composition of urinary stone powders directly from the urine samples after the URSL procedure. This approach provides a quick and convenient method for urinary stone analysis. Copyright © 2009 John Wiley & Sons, Ltd.     

The effect of oral administration of calcium and magnesium on intestinal oxalate absorption in humans

Calcium oxalate (CaOx) urolithiasis is the most common urinary stone disease (70-75 % of all stones consist of CaOx in countries with western diet). Oxalate is the most lithogenic substance in CaOx crystallisation in urine. Oxalate is either synthesized within the body or absorbed from food. As oxalate is not metabolized in the human body, it appears unchanged in urine. Conventional analysis methods cannot distinguish between endogenous and exogenous oxalate. Our [13C2]oxalate absorption test enabled measurement of intestinal oxalate absorption and quantification of the influence of Ca- and Mg-supplementation on it. The effects of the oral administration of these supplements were compared in order to obtain valid data for recommendations for CaOx urolithiasis patients. A 10 mmol supplement of both ions decreased the oxalate absorption significantly, calcium being more than twice as effective.     

海带多糖对草酸钙结晶过程中晶相的影响

采用X射线衍射(XRD)、红外光谱(FTIR)、扫描电子显微镜(SEM)和原子吸收光谱(AAS)等方法研究了从海带中提取的硫酸多糖(SPS)对尿结石主要成分草酸钙结晶的影响。SPS可以稳定热力学亚稳定的二水草酸钙(COD)晶体。随着SPS浓度从0增加到0.60 mg·mL-1,COD晶体的质量百分比从0增加到100％;亚稳溶液中草酸钙的相对过饱和度从1.0增加到19.6。SPS可以稳定COD晶体在溶液中的存在并增加可溶性Ca2+离子的浓度,这有利于防止草酸钙结石形成。结果表明,SPS是一种潜在的防止草酸钙尿结石形成的药物。     

EDXRF,FTIR, and XRD characterization of low calcium oxalate urinary stones collected from arid area

Low calcium oxalate urinary stones from the kidney, bladder, and ureter have been collected from the arid area (Taif, Saudi Arabia). After careful washing and drying of the collected stones, the samples were converted into a contamination-free homogenous fine powder with a particles' size smaller than 50 μm. The processed urinary stone powders were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), laboratory setup and synchrotron radiation X-ray diffraction (XRD), and energy-dispersive X-ray fluorescence (EDXRF). The activated function groups, quantitative phase analysis, and the semi-quantitative elemental analysis of the present urinary stones were identified. Seventeen elements were measured in most of the urinary stone samples. The significant elements are Ca, P, S, Cl, Zn, K, Fe, and Cu, whereas other elements were found alternatively in a few number of urinary stone samples. It was recognized that Ca exists with low concentration, which indicates the presence of different calcium phases even with low percentages. In 33% of the urinary stones, the phosphorus (P) was not measured, but there were high concentrations of sulfur (S) and low concentrations of Ca up to 2.15 ± 0.05%. The ATR-FTIR results indicate that the most compounds of the present urinary stones were urea and cystine combined with low ratios of calcium oxalate and calcium phosphate compounds. The quantitative phase analysis of the XRD of selected samples proves the presence of the cystine, urea, and calcium oxalate phases with different weight percent.     

Infrared Analysis of Urinary Stones,Using a Single Reflection Accessory and a KBr Pellet Transmission*

This work is a comparative study of two FTIR techniques applied to urinary stones analysis: single reflection diamond attenuated total reflection (ATR) and KBr pellet transmission (KPT). We show that the two methods allow the identification of all stone components. The ATR technique is more useful and rapid to identify the species without sample pretreatment. Nevertheless, KPT is more appropriate for components determination in urinary stones.

These techniques were applied to the study of a series of 313 calculi. The stone constituents were first identified by ATR, and in a second step, the proportion of each species present in the stone was determined by KPT in whole‐stone mixture.

The results obtained showed the presence of 11 different components classified as follows with the frequency of detection in the stones studied: calcium oxalate monohydrate (whewellite), 78.9%; carbapatite, 33.9%; calcium oxalate dihydrate (weddellite), 24%; uric acid anhydrous, 19.2%; ammonium hydrogen urate, 7%; struvite, 4.8%; cystine, 1%; ammonium sodium urate and other phosphates (amorphous carbonated calcium phosphate, brushite, whitlockite), each in less than 1%.