研究报告本出版物中被休斯敦大学新学院格兰特，从德州超导中心的种子批，并在美国化学学会石油研究基金（52537-DNI）的支持。

的胶体聚合物的混合物1。准备注意：该协议使用的聚（甲基丙烯酸甲酯）（PMMA）粒子，空间稳定使用聚（12 - 羟基硬脂酸）和标记有荧光染料（如尼罗红，若丹明B，或荧光素），合成了以下的标准即配方52。 <ol><li>准备3:1 w / w的环己基溴化铵（CXB​​）和十氢萘（DHN）作为股票溶剂的混合物。此混合物几乎与折射颗粒的密度和索引。添加的有机盐，四丁基氯化铵（TBAC）46，向溶剂中在1.5 mM的浓度，以部分屏幕上的粒子的电荷。 </li><li>精确地确定粒子的密度，制备悬浮液在近似颗粒体积分数Φ=中的CXB 0.10：DHN溶剂。离心悬浮液，在800×g离心75分钟，并加CXB或DHN滴加提高浮力匹配。在这些实验中，聚甲基丙烯酸甲酯粒子的密度测定为ρ=1.223克/毫升。 </li><li>制备浓缩的纸浆悬浮液的PMMA粒子（此处，Φ= 0.40）中的CXB：DHN溶剂混合物。 </li><li>备中的CXB线性聚苯乙烯（PS）的浓溶液：DHN溶剂混合物。这里，分子量M PS的解w≈3000000（回转R G = 15nm的半径）的制备在浓度C P≈50毫克/毫升。 </li><li>混合颗粒，聚合物和溶剂的原料混合物的适当的权重，以制定悬浮在粒子和聚合物的所需浓度。 注意：在这里，单分散颗粒的悬浮液制备成胶体恒定体积分数Φ= 0.15和可变的聚合物浓度中的自由体积53 C P = 0-25毫克/毫升，并bidispersed含有两种尺寸的胶体颗粒的悬浮液，瓦特第i个大小各带有一个独特的荧光标记，制备固定于胶体总体积分数Φ=小颗粒为0.15，体积分数比r = 0.50，和聚合物浓度为5或25毫克/毫升的自由体积。 </li><li>后各悬浮液制备中，添加CXB或DHN溶液并离心样品在800×g离心至少75分钟，以确认该悬浮液中的颗粒和簇保持浮力匹配。 </li><li>平衡所有样品至少24小时前成像实验。 </li></ol> 2，静态实​​验样品：相行为<ol><li>要确定体相行为，制造玻璃盖玻片（ 图1a）矩形腔。用于本研究中的胶体聚合物的混合物，厚度为h = 1毫米（通过显微镜载玻片的厚度设定）腔室给散装的行为。 </li><li>要访问一个单一的显微镜实验多接产，制作薄楔形形腔，使用一个单一的盖玻片作为在一个楔形的垫片（ 图1b）。该腔室的开口角度为&lt;0.5°，以便在视图中的单个字段的壁非常接近平行。一位代表室允许访问限制厚度为h = 6〜&gt; 100微米。 </li><li>构建室上盖玻片基地成像于倒置显微镜和密封用紫外线固化型环氧树脂，它不会在CXB-DHN溶剂混合物中溶解。 </li><li>使用共聚焦显微镜图像样本。这个协议示范成像与连接到倒置显微镜配备有数值孔径的100X油镜NA = 1.40的线扫描共焦。 </li><li>使用激光源激发的染料。这里波长λ= 491或561 nm的用于激发荧光素和若丹明/尼罗红染料，分别。 </li><li>在点扫描系统，通过快速扫描整个样品的焦点（在x生成图像y平面）使用共聚焦软件。的512个像素的二维图像×512像素，覆盖大约50微米×50微米，可以在1/32秒来获得。通过平均多个图像或增加采集时间提高了图象质量。 </li><li>找到该腔室的底部（Z = 0），例如通过集中颗粒附着到其底部。在这种设置中，高度（Z）增加而增加重点放到室。 </li><li>作为一个例子，通过在腔室的中间平面获得的2-D的时间序列图像（在xy平面内）表征的颗粒的动力学限制的效果。在一个典型的实验中，尺寸为500的图像512像素×512像素，在1帧/秒的帧速率（时间间隔ΔT= 1秒）获取。 </li><li>作为第二个例子，通过获得的三维图像系列（的x，y，z）的表征颗粒的3-D结构。在一个典型的实验中，二维图像（512像素×512像素）的在腔室中的多个Z轴位置获得的，与Δ狕的恒定间距=0.2μm的由压电设置连续的图像间。卷叠覆盖厚度为h = 30微米因此包含151的图像。 </li><li>找到并使用用IDL编写23,54-56，MATLAB 57,58，59的LabView或Python 60粒子跟踪软件随着时间的推移跟踪颗粒在2-D或3-D。这些算法通常允许颗粒的中心被内40-50 nm的解决。成功的粒子跟踪要求粒子运动少于连续帧之间的粒子间距。 </li><li>从粒子的位置，计算结构和动态指标。这里显示三个方便的指标是3-D对关联函数g（r）61，2-D均方位移（MSD）58,62，和面包车霍夫相关函数G S的2-D的自我的一部分（ X，T）58。后两种度量也可以计算出在3-D。 </li></ol> 3，重排实验：流动性能<ol><li>使用具有正方形横截面（100微米×100微米），其固定到特氟隆管的玻璃微毛细管制作一个简单的流动池。使用玻璃盖玻片上，以支持所述毛细管和提供机械刚性，如图所示，在图7中的原理图。 </li><li>加载胶体的聚合物混合物制成的玻璃注射器中。连接注射器的注射器泵或气动流体分配系统。 </li><li>安装流动池安装到倒置显微镜。保持注射器，流通池和出口在相同的高度，以尽量减少重力对流量分布的影​​响。 </li><li>过流动池的体积流量（对于注射泵）或所施加的压力（压力盒）控制悬浮液的流速。悬挂在微通道的平均速度还取决于苏spension配方。在正方形微这里测得的最大流速的典型值是200-2,000微米/秒。 </li><li>在流，获得一个二维共焦时间序列的帧速率。这里，尺寸为500的图像512像素×512像素，32帧/秒获取的（时间间隔ΔT = 1/32秒）在不同高度上的微通道的底部（z = 0的微米）以上，从Z = 5 - 50微米。每个图像包括大约一半的微通道的横向尺寸（Y），如图所示在嵌入到图7。如果颗粒呈现为椭圆形，增加采集的帧速率。 </li><li>在静态实验，找出使用标准算法，用于定位和跟踪的IDL或MATLAB粒子在二维颗粒。缓慢流动，在这种粒子移动小于帧之间的平均粒子间距，使用跟踪算法得到的轨迹。 </li><li>利用图像的相关性为钙乌拉特快速流动的速度分布。 <ol><li>细分图象划分为恒定高度（y）的沿流动方向的水平的图像（X）。对于两个连续的图像I 1（X，Y）和I 2（X，Y）的一个因素ΔX转移后的图像，然后计算之间的I 1（X，Y）的互协方差和I 2（X +ΔX， Y）。 </li><li>确定ΔX值，最大限度地提高各个图像对之间的互协方差以获得在每个横向位置 y的平均对流速度的直方图的峰值位置。如果这种分配不是强见顶，以更快的帧速率采集图像。 </li></ol></li></ol>

作者什么都没有透露。

胶态悬浮液被广泛地研究了作为密闭相行为模型，由于微米级的胶体颗粒具有比原子和分子显著缓慢的动态特性，因此可以容易地成像并随时间跟踪10。对于这些基础研究，了解粒子间的景点上局限于相行为的影响提供了机会，探索，如毛细管冷凝和蒸发21,22,67现象。此外，密闭吸引力的悬浮液出现无处不在工业和技术的应用。对于这些应用的研究，了解悬浮液制剂的有关密闭流?...

本文演示了静态和流动的密闭胶体聚合物中二和混合三个维度及（b）粒子跟踪和相关的合成图像的分析，以获得对相态和流动性的定量信息（一）共焦成像。 胶体悬浮液有吸引力的粒子间的相互作用似乎无处不在的技术应用，材料的定向组装1-3，给药4，提高油气采收率5-7，和储能8。这些应用的一个共同特点是，粒子必须通过精细的几何形状，如喷嘴，打印头，微通道，或者多孔介质中流动，和/或成型为薄膜或棒。用于探测在密闭的几何形状，包括电子显微镜17,18，X射线显微镜，19，和激光衍射米微米大小的胶体结构的技术镜检20，可用于测量在微尺度粒子的结构和动力学。这些技术，然而，不允许访问的单个颗粒，从该结构和动态度量可以计算为直接比较数值模拟21,22的轨迹。 共聚焦显微镜的荧光显微镜的一个变种，它使的荧光样品的薄切片成像。对于胶体科学10，此技术是用于深内稠密的悬浮液或在三维成像中特别有用。粒子跟踪算法23适用于二维或三维的时间序列共聚焦显微照片产生所有可见的粒子的运动轨迹。其结果是，激光共聚焦显微镜和粒子跟踪的组合已被用于研究的相行为，结构和胶态悬浮液的动力学，包括有序的晶体24-27和紊乱海关眼镜28-31和32-35的凝胶。 其他图像分析算法可以应用于从时间序列的共聚焦显微照片测量粒子动力学。例如，扩散粒子动力学可以通过分析利用共聚焦微分动力显微镜36的强度随时间的波动进行研究。当粒子的位移比颗粒间间距大，根据粒子图像测速38-40图像相关性37可以应用到测量颗粒的速度分布。的跟踪和相关算法相结合，使胶体动力学在经历缓慢和快速流动11-16,41-45系统进行测量。 我们用胶体聚合物混合物作为有吸引力的胶体悬浮液9款车型。在这些混合物中，颗粒间的吸引力电位的范围和强度是通过比率控制回转半径聚合物与颗粒半径与聚合物和静电斥力的浓度通过添加一价有机盐46进行控制。因为颗粒间的相互作用，可以仔细调整，这些混合物的凝固进行了广泛研究以共焦显微镜34,47-51。 在这里，我们展示了共焦成像的静止和流动的胶体聚合物混合物和图像分析37，其中胶体体积分数为Φ保持固定= 0.15，即探头禁闭的相行为和这些混合物的流动性能的影响。这些技术广泛适用于颗粒系统，是折射率匹配的，并且其中的颗粒和/或溶剂可以标记有荧光染料。

<table border="0" cellpadding="0" cellspacing="0" style="width:752px;" width="751">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Name of Material/ Equipment</td>
			<td style="width:103px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:315px;">Comments/Description</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Cyclohexyl bromide</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">135194</td>
			<td style="width:315px;">CAS Number&#160; 108-85-0, Molecular wt. =163.06, Used in stock solvent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Decahydronapthalene</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">D251</td>
			<td style="width:315px;">CAS Number 91-17-8, Molecular wt. = 138.25, Used in stock solvent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Nile Red</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">72485</td>
			<td style="width:315px;">Fluorescent dye</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Fluorescein 5(6)-isothiocyanate</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">F3651</td>
			<td style="width:315px;">Fluorescent dye</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rhodamine B</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">83689</td>
			<td style="width:315px;">Fluorescent dye</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Dynamic Light Scattering&#160;</td>
			<td style="width:103px;">Brookhaven Instruments</td>
			<td style="width:119px;">BI-APD</td>
			<td style="width:315px;">DLS equipment used for particle size measurement</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Polystyrene&#160;</td>
			<td style="width:103px;">Varian/Agilent</td>
			<td style="width:119px;">PL20138-23</td>
			<td style="width:315px;">Polystyrene (polymer) for inducing depletion attraction</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">tetrabutyl(ammonium chloride) (TBAC)</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">86870</td>
			<td style="width:315px;">monovalent salt</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Cover slips</td>
			<td style="width:103px;">Fisher Scientific</td>
			<td style="width:119px;">12-518-210&#160;</td>
			<td style="width:315px;">48&#10761;65 mm</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Cover slips</td>
			<td style="width:103px;">Fisher Scientific</td>
			<td style="width:119px;">12-540B</td>
			<td style="width:315px;">22&#10761;22 mm</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">UV Adhesive</td>
			<td style="width:103px;">Norland Adhesive</td>
			<td style="width:119px;">NOA 68T</td>
			<td style="width:315px;">Part Number 68T01 (UV cured adhesive)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">VT Eye</td>
			<td style="width:103px;">Visitech</td>
			<td style="width:119px;">VT Eye</td>
			<td style="width:315px;">confocal scanner</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">VT Infinity</td>
			<td style="width:103px;">Visitech</td>
			<td style="width:119px;">VT Infinity</td>
			<td style="width:315px;">confocal scanner</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Microscope&#160;</td>
			<td style="width:103px;">Leica</td>
			<td style="width:119px;">DMI3000B</td>
			<td style="width:315px;">Inverted Microscope</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Centrifuge</td>
			<td style="width:103px;">Thermo Scientific&#160;</td>
			<td style="width:119px;">Sorvall ST 16</td>
			<td style="width:315px;">1-5000 rpm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glass slides</td>
			<td style="width:103px;">VWR</td>
			<td style="width:119px;">48382-171</td>
			<td style="width:315px;">25&#10761;75 mm, 1.0 mm thick</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">microcapillary</td>
			<td style="width:103px;">Vitrocom</td>
			<td style="width:119px;">8510-100</td>
			<td style="width:315px;">0.1&#10761;0.1 mm square cross section, 100 mm length</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Teflon tubing</td>
			<td style="width:103px;">smallparts</td>
			<td style="width:119px;">SLTT 26-72</td>
			<td style="width:315px;">Zeus PTFE Sublite Wall Tubing 26 AWG .016&#34; ID x .0030&#34; Wall</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Epoxy</td>
			<td style="width:103px;">Devcon</td>
			<td style="width:119px;">DA051</td>
			<td style="width:315px;">5 minute epoxy</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Syringe</td>
			<td style="width:103px;">Micromate/Cadence</td>
			<td style="width:119px;">5004</td>
			<td style="width:315px;">glass syringe with metal luer lock tip</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Syringe tips&#160;</td>
			<td style="width:103px;">Nordson</td>
			<td align="right">7018462</td>
			<td style="width:315px;">32 GA precision tips&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Syringe pump&#160;</td>
			<td style="width:103px;">New Era Pump system Inc.&#160;</td>
			<td style="width:119px;">NE1002X</td>
			<td style="width:315px;">Programmable microfluidic pump (syringepump.com)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Weigh balance</td>
			<td style="width:103px;">Mettler Toledo</td>
			<td style="width:119px;">AB204-S</td>
			<td style="width:315px;">0.0001-220 g</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PMMA particles</td>
			<td style="width:103px;">synthesized</td>
			<td style="width:119px;"></td>
			<td style="width:315px;">poly(methylmethacrylate) colloidal particles</td>
		</tr>
	</tbody>
</table>

confocal imaging of confined quiescent and flowing colloid-polymer mixtures

密闭胶体悬浮有吸引力间相互作用的行为是合理设计的材料的定向组件1-3，给药4，改进的烃采收5-7，和对能量存储装置8流动的电极是至关重要的。含有荧光性胶体和非吸附性的聚合物悬浮液吸引人的模型系统中，如回转聚合物半径分别向范围和颗粒间的吸引力的强度，粒子半径控制聚合物的浓度和比例。通过调节聚合物的性质和胶体的体积分数，胶体液，簇的液体，凝胶，晶体，和眼镜可以得到9。 共聚焦显微镜，荧光显微镜的一个变型中，允许一个光学透明和荧光样品将被成像以高空间和在三维空间中的时间分辨率。在该技术中，一个小针孔或由属于显微镜的光学系统的焦点容积之外的样品区域狭缝块所发出的荧光。其结果是，样品在焦平面只有一个薄截面进行成像。此技术特别适合于单粒子尺度来探测在稠密的胶体悬浮液的结构和动力学：颗粒是足够大，以利用可见光来解决和扩散足够缓慢以商业共聚焦系统10的典型的扫描速度被捕获。在扫描速度和分析算法的改进也使流动的悬浮液 11-16,37 定量共聚焦成像。在本文中，我们演示了激光共聚焦显微镜实验来探测局限相行为和胶体聚合物混合物的流动性能。我们先准备科尔是密度和折射率的OID的聚合物的混合物相匹配。接下来，我们提出一个标准协议，用于在不同的约束薄楔形细胞成像静态密集的胶体聚合物的混合物。最后，我们展示了一个协议，用于微流在成像胶体聚合物的混合物。

为了证明共聚焦成像和粒子跟踪，我们调查坐月子对胶体聚合物混合物63-65相行为的影响。这些实验的胶体粒径为2 = 0.865微米。胶体体积分数固定为Φ= 0.15和聚合物 c p的浓度变化为0至23.6毫克/毫升。代表性的共聚焦图像显示在图2中 63，左边的列。使用跟踪算法得到的颗粒归仓，我们计算出的代表结构和动态指标，包括对相关函数（ ?...

Watch this Scientific Journal Video about Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures at JoVE.com

Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures

共聚焦显微术用于图像的静态和流动的胶体聚合物的混合物，这是研究作为模型系统的吸引力悬浮液。图像分析算法来计算结构和动态度量用于测量由于几何约束变化的胶体粒子。

密闭静态和流动胶体聚合物混合物的共聚焦成像

The behavior of confined colloidal suspensions with attractive interparticle interactions is critical to the rational design of materials for directed ...

confocal-imaging-confined-quiescent-flowing-colloid-polymer

Research

JoVE Journal

Chemistry

12.0K 次观看.  University of Houston. 共聚焦显微术用于图像的静态和流动的胶体聚合物的混合物，这是研究作为模型系统的吸引力悬浮液。图像分析算法来计算结构和动态度量用于测量由于几何约束变化的胶体粒子。 

视频: Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures

Synthesis of Immunotargeted Magneto-plasmonic Nanoclusters

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications including contrast enhancement in novel magnetomotive imaging modalities, simultaneous capture&#160;and detection of circulating tumor cells (CTCs),&#160;and multimodal molecular imaging combined with photothermal therapy of cancer cells. These applications have stimulated significant interest in development of protocols for synthesis of magneto-plasmonic nanoparticles with optical absorbance in the near-infrared (NIR) region and a strong magnetic moment. Here, we present a novel protocol for synthesis of such hybrid nanoparticles that is based on an oil-in-water microemulsion method. The unique feature of the protocol described herein is synthesis of magneto-plasmonic nanoparticles of various sizes from primary blocks which also have magneto-plasmonic characteristics. This approach yields nanoparticles with a high density of magnetic and plasmonic functionalities which are uniformly distributed throughout the nanoparticle volume. The hybrid nanoparticles can be easily functionalized by attaching antibodies through the Fc moiety leaving the Fab portion that is responsible for antigen binding available for targeting.

Here, we describe a protocol for synthesis of magneto-plasmonic nanoparticles with a strong magnetic moment and a strong near-infrared (NIR) absorbance. The protocol also includes antibody conjugation to the nanoparticles through the Fc moiety for various biomedical applications which require molecular specific targeting.

Immunotargeted的合成磁等离子团簇

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications ...

科研

化学

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance imaging (MRI). Their purpose is to enhance the relaxation rate of water protons in tissue, thus increasing the MR image contrast and the specificity of the MRI measurements. Current clinically approved contrast agents are low molecular weight molecules that are rapidly cleared from the body. The use of dendrimers as carriers of paramagnetic chelators can play an important role in the future development of more efficient MRI contrast agents. Specifically, the increase in local concentration of the paramagnetic species results in a higher signal contrast. Furthermore, this CA provides a longer tissue retention time due to its high molecular weight and size. Here, we demonstrate a convenient procedure for the preparation of macromolecular MRI contrast agents based on poly(amidoamine) (PAMAM) dendrimers with monomacrocyclic DOTA-type chelators (DOTA &#8211; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). The chelating unit was appended by exploiting the reactivity of the isothiocyanate (NCS) group towards the amine surface groups of the PAMAM dendrimer to form thiourea bridges. Dendrimeric products were purified and analyzed by means of nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. Finally, high resolution MR images were recorded and the signal contrasts obtained from the prepared dendrimeric and the commercially available monomeric agents were compared.

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

This protocol describes the preparation and characterization of a dendrimeric magnetic resonance imaging (MRI) contrast agent that carries cyclen-based macrocyclic chelates coordinating paramagnetic gadolinium ions. In a series of MRI experiments in vitro, this agent produced an amplified MRI signal when compared to the commercially available monomeric analogue.

制备及<em&gt;体外</em&gt;磁共振成像基于树状大分子造影剂的表征

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...

Direct Imaging of Laser-driven Ultrafast Molecular Rotation

We present a method for visualizing laser-induced, ultrafast molecular rotational wave packet dynamics. We have developed a new 2-dimensional Coulomb explosion imaging setup in which a hitherto-impractical camera angle is realized. In our imaging technique, diatomic molecules are irradiated with a circularly polarized strong laser pulse. The ejected atomic ions are accelerated perpendicularly to the laser propagation. The ions lying in the laser polarization plane are selected through the use of a mechanical slit and imaged with a high-throughput, 2-dimensional detector installed parallel to the polarization plane. Because a circularly polarized (isotropic) Coulomb exploding pulse is used, the observed angular distribution of the ejected ions directly corresponds to the squared rotational wave function at the time of the pulse irradiation. To create a real-time movie of molecular rotation, the present imaging technique is combined with a femtosecond pump-probe optical setup in which the pump pulses create unidirectionally rotating molecular ensembles. Due to the high image throughput of our detection system, the pump-probe experimental condition can be easily optimized by monitoring a real-time snapshot. As a result, the quality of the observed movie is sufficiently high for visualizing the detailed wave nature of motion. We also note that the present technique can be implemented in existing standard ion imaging setups, offering a new camera angle or viewpoint for the molecular systems without the need for extensive modification.

We present a protocol for creating a real-time movie of a molecular rotational wave packet using a high-resolution Coulomb explosion imaging setup.

激光驱动的超快分子旋转直接成像

We present a method for visualizing laser-induced, ultrafast molecular rotational wave packet dynamics. We have developed a new 2-dimensional Coulomb ...

Measurements of Long-range Electronic Correlations During Femtosecond Diffraction Experiments Performed on Nanocrystals of Buckminsterfullerene

The precise details of the interaction of intense X-ray pulses with matter are a topic of intense interest to researchers attempting to interpret the results of femtosecond X-ray free electron laser (XFEL) experiments. An increasing number of experimental observations have shown that although nuclear motion can be negligible, given a short enough incident pulse duration, electronic motion cannot be ignored. The current and widely accepted models assume that although electrons undergo dynamics driven by interaction with the pulse, their motion could largely be considered &#39;random&#39;. This would then allow the supposedly incoherent contribution from the electronic motion to be treated as a continuous background signal and thus ignored. The original aim of our experiment was to precisely measure the change in intensity of individual Bragg peaks, due to X-ray induced electronic damage in a model system, crystalline C60. Contrary to this expectation, we observed that at the highest X-ray intensities, the electron dynamics in C60 were in fact highly correlated, and over sufficiently long distances that the positions of the Bragg reflections are significantly altered. This paper describes in detail the methods and protocols used for these experiments, which were conducted both at the Linac Coherent Light Source (LCLS) and the Australian Synchrotron (AS) as well as the crystallographic approaches used to analyse the data.

We describe an experiment designed to probe the electronic damage induced in nanocrystals of Buckminsterfullerene (C60) by intense, femtosecond pulses of X-rays. The experiment found that, surprisingly, rather than being stochastic, the X-ray induced electron dynamics in C60 are highly correlated, extending over hundreds of unit cells within the crystals1.

在纳米富勒的飞秒衍射实验的长程电子关联的测量

The precise details of the interaction of intense X-ray pulses with matter are a topic of intense interest to researchers attempting to interpret the ...

Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol

The purification of organic compounds is an essential component of routine synthetic operations. The ability to remove contaminants into an aqueous layer by generating a charged structure provides an opportunity to use extraction as a simple purification technique. By combining the use of a miscible organic solvent with saturated sodium bisulfite, aldehydes and reactive ketones can be successfully transformed into charged bisulfite adducts that can then be separated from other organic components of a mixture by the introduction of an immiscible organic layer. Here, we describe a simple protocol for the removal of aldehydes, including sterically-hindered neopentyl aldehydes and some ketones, from chemical mixtures. Ketones can be separated if they are sterically unhindered cyclic or methyl ketones. For aliphatic aldehydes and ketones, dimethylformamide is used as the miscible solvent to improve removal rates. The bisulfite addition reaction can be reversed by basification of the aqueous layer, allowing for the re-isolation of the reactive carbonyl component of a mixture.

Here, we present a protocol to remove aldehydes and reactive ketones from mixtures by a liquid-liquid extraction protocol directly with saturated sodium bisulfite in a miscible solvent. This combined protocol is rapid and facile to perform. The aldehyde or ketone can be re-isolated by the basification of the aqueous layer.

用亚硫酸氢萃取协议分离混合物中的醛和反应性酮

The purification of organic compounds is an essential component of routine synthetic operations. The ability to remove contaminants into an aqueous layer ...

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Disaccharide nucleosides, which consist of disaccharide and nucleobase moieties, have been known as a valuable group of natural products having multifarious bioactivities. Although chemical O-glycosylation is a commonly beneficial strategy to synthesize disaccharide nucleosides, the preparation of substrates such as glycosyl donors and acceptors requires&#160;tedious protecting&#160;group manipulations and a purification at each synthetic step. Meanwhile, several research groups have reported that boronic and borinic esters serve as a protecting or activating group of carbohydrate derivatives to achieve the regio- and/or stereoselective acylation, alkylation, silylation, and glycosylation. In this article, we demonstrate the procedure for the regioselective O-glycosylation of unprotected ribonucleosides utilizing boronic acid. The esterification of 2&#39;,3&#39;-diol of ribonucleosides with boronic acid makes the temporary protection of diol, and, following O-glycosylation with a glycosyl donor in the presence of p-toluenesulfenyl chloride and silver triflate, permits the regioselective reaction of the 5&#39;-hydroxyl group to afford the disaccharide nucleosides. This method could be applied to various nucleosides, such as guanosine, adenosine, cytidine, uridine, 5-metyluridine, and 5-fluorouridine. This article and the accompanying video represent&#160;useful (visual) information for the O-glycosylation of unprotected nucleosides and their analogs for the synthesis of not only disaccharide nucleosides, but also a variety of biologically relevant derivatives.

Regioselective O-Glycosylation of Nucleosides via the Temporary 2&#039;,3&#039;-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Here, we present protocols for the synthesis of disaccharide nucleosides by the regioselective O-glycosylation of ribonucleosides via a temporary protection of their 2&#39;,3&#39;-diol moieties utilizing a cyclic boronic ester. This method applies to several unprotected nucleosides such as adenosine, guanosine, cytidine, uridine, 5-methyluridine, and 5-fluorouridine to give corresponding disaccharide nucleosides.

苷 2 ', 3 ' -二醇酯对双糖苷合成的选择性O-糖基化

Disaccharide nucleosides, which consist of disaccharide and nucleobase moieties, have been known as a valuable group of natural products having ...

Automation of a Positron-emission Tomography (PET) Radiotracer Synthesis Protocol for Clinical Production

The development of new positron-emission tomography (PET) tracers is enabling researchers and clinicians to image an increasingly wide array of biological targets and processes. However, the increasing number of different tracers creates challenges for their production at radiopharmacies. While historically it has been practical to dedicate a custom-configured radiosynthesizer and hot cell for the repeated production of each individual tracer, it is becoming necessary to change this workflow. Recent commercial radiosynthesizers based on disposable cassettes/kits for each tracer simplify the production of multiple tracers with one set of equipment by eliminating the need for custom tracer-specific modifications. Furthermore, some of these radiosynthesizers enable the operator to develop and optimize their own synthesis protocols in addition to purchasing commercially-available kits. In this protocol, we describe the general procedure for how the manual synthesis of a new PET tracer can be automated on one of these radiosynthesizers and validated for the production of clinical-grade tracers. As an example, we use the ELIXYS radiosynthesizer, a flexible cassette-based radiochemistry tool that can support both PET tracer development efforts, as well as routine clinical probe manufacturing on the same system, to produce [18F]Clofarabine ([18F]CFA), a PET tracer to measure in vivo deoxycytidine kinase (dCK) enzyme activity. Translating a manual synthesis involves breaking down the synthetic protocol into basic radiochemistry processes that are then translated into intuitive chemistry &#34;unit operations&#34; supported by the synthesizer software. These operations can then rapidly be converted into an automated synthesis program by assembling them using the drag-and-drop interface. After basic testing, the synthesis and purification procedure may require optimization to achieve the desired yield and purity. Once the desired performance is achieved, a validation of the synthesis is carried out to determine its suitability for the production of the radiotracer for clinical use.

Automation of a Positron-emission Tomography PET Radiotracer Synthesis Protocol for Clinical Production

Positron-emission tomography (PET) imaging sites that are involved in multiple early clinical research trials need robust and versatile radiotracer manufacturing capabilities. Using the radiotracer [18F]Clofarabine as an example, we illustrate how to automate the synthesis of a radiotracer using a flexible, cassette-based radiosynthesizer and validate the synthesis for clinical use.

用于临床生产的正电子发射层析成像 (PET) 放射性同位素示踪合成协议的自动化

The development of new positron-emission tomography (PET) tracers is enabling researchers and clinicians to image an increasingly wide array of biological ...

Imaging Corrosion at the Metal-Paint Interface Using Time-of-Flight Secondary Ion Mass Spectrometry

Corrosion developed at the paint and aluminum (Al) metal-paint interface of an aluminum alloy is analyzed using time-of-flight secondary ion mass spectrometry (ToF-SIMS), illustrating that SIMS is a suitable technique to study the chemical distribution at a metal-paint interface. The painted Al alloy coupons are immersed in a salt solution or exposed to air only. SIMS provides chemical mapping and 2D molecular imaging of the interface, allowing direct visualization of the morphology of the corrosion products formed at the metal-paint interface and mapping of the chemical after corrosion occurs. The experimental procedure of this method is presented to provide technical details to facilitate similar research and highlight pitfalls that may be encountered during such experiments.

Time-of-flight secondary ion mass spectrometry is applied to demonstrate the chemical mapping and corrosion morphology at the metal-paint interface of an aluminum alloy after being exposed to a salt solution compared with a specimen exposed to air.

利用飞行时二次离子质谱法成像金属颜料界面的腐蚀

Corrosion developed at the paint and aluminum (Al) metal-paint interface of an aluminum alloy is analyzed using time-of-flight secondary ion mass ...

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands for in vivo investigations. Within this protocol, a robust and reliable remote-controlled radiosynthesis of [11C]SNAP-7941, an antagonist to the melanin-concentrating hormone receptor 1, is described. The radiosynthesis starts with cyclotron produced [11C]CO2 that is subsequently further reacted via a gas-phase transition to [11C]CH3OTf. Then, this reactive intermediate is introduced to the precursor solution and forms the respective radiotracer. Chemical as well as the radiochemical purity are determined by means of RP-HPLC, routinely implemented in the radiopharmaceutical quality control process. Additionally, the molar activity is calculated as it is a necessity for the following real-time kinetic investigations. Furthermore, [11C]SNAP-7941 is applied to MDCKII-WT and MDCKII-hMDR1 cells for evaluating the impact of P-glycoprotein (P-gp) expression on cell accumulation. For this reason, the P-gp expressing cell line (MDCKII-hMDR1) is either used without or with blocking prior to experiments by means of the P-gp substrate (&#177;)-verapamil and the results are compared to the ones observed for the wildtype cells. The overall experimental approach demonstrates the importance of a precise time-management that is essential for every preclinical and clinical study using PET tracers radiolabelled with short-lived nuclides, such as carbon-11 (half-life: 20 min).

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

Here, we represent a protocol for the fully automated radiolabelling of [11C]SNAP-7941 and the analysis of the real-time kinetics of this PET-tracer on P-gp expressing and non-expressing cells.

[11C_SNAP-7941] 自动合成和实时动力学评估的技术方面

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands ...

Resolving Water, Proteins, and Lipids from In Vivo Confocal Raman Spectra of Stratum Corneum through a Chemometric Approach

Development of this in vivo confocal Raman spectroscopic method enables the direct measurement of water, proteins, and lipids with depth resolution in human subjects. This information is very important for skin-related diseases and characterizing skin care product performance. This protocol illustrates a method for confocal Raman spectra collection and the subsequent analysis of the spectral dataset leveraging chemometrics. The goal of this method is to establish a standard protocol for data collection and provide general guidance for data analysis. Preprocessing (e.g., removal of outlier spectra) is a critical step when processing large datasets from clinical studies. As an example, we provide guidance based on prior knowledge of a dataset to identify the types of outliers and develop specific strategies to remove them. A principal component analysis is performed, and the loading spectra are compared with spectra from reference materials to select the number of components used in the final multivariate curve resolution (MCR) analysis. This approach is successful for extracting meaningful information from a large spectral dataset.

Here, we present a protocol for collection of confocal Raman spectra from human subjects in clinical studies combined with chemometric approaches for spectral outlier removal and the subsequent extraction of key features.

通过化学测量方法，从活体共聚焦拉曼光谱中解决水、蛋白质和脂质

Development of this in vivo confocal Raman spectroscopic method enables the direct measurement of water, proteins, and lipids with depth resolution in ...