MRI 本质上还是一维 NMR ，只不过多个方向上扫描。 二维 NMR 一般包括： correlation spectroscopy (COSY), J-spectroscopy, exchange spectroscopy (EXSY), and nuclear Overhauser effect spectroscopy (NOESY) 。 COSY 原理很简单，可以找出两个有关联的 chemical shift 。会出现 diagonal peaks 和 cross peaks 。 TOCSY （ Total correlation spectroscopy ）跟 COSY 很类似，但除了可以观测到直接关联的 cross peaks ，还可以观测到间接关联在一起的 cross peaks. 【历史】 The first two-dimensional experiment, COSY, was proposed by Jean Jeener, a professor at the Université Libre de Bruxelles, in 1971. (Theoretically) This experiment was later implemented by Walter P. Aue, Enrico Bartholdi and Richard R. Ernst (1991 Nobel prize), who published their work in 1976. Ernst出席了13届生物物理大会(IUPAB)，我参加的是第8届生物物理大会（IUPAP），不要混淆。 【 chemical shift 】 In nuclear magnetic resonance (NMR) spectroscopy, the chemical shift is the resonant frequency of a nucleus relative to a standard in a magnetic field. Often the position and number of chemical shifts are diagnostic of the structure of amolecule . 参考复旦的实验原理！劈裂成两个方向，说明出现了类似 ising model 一样的两种自旋方向。当 RF 为二者之差时，低能向高能跃迁。 拉莫尔公式： 其中 γ 为旋磁比。进一步，原子核在磁场下的分裂的能级间距为： 质子的拉莫尔频率为 42.5MHz 。 Chemical shift δ is usually expressed in parts per million (ppm) ： 所以 ， 1ppm=1Hz per 100MHz ， 也就是 42.5Hz chemical shift。
时间到了 1950 年， Bloch 实验室的两名博士后， Warren Proctor 和虞福春，发现了化学位移现象，核磁共振开始在分析化学领域大显身手，接力棒由此也传到了化学家手上。 从事核磁共振研究的两位诺贝尔化学奖得主均为瑞士人，同在苏黎世理工任教。 Richard Ernst 对核磁共振波谱分析的方法做出了巨大的贡献。他发明的把脉冲波和傅里叶变换相结合的方法，不仅大大提高了实验的效率，也开拓出了多维核磁共振波谱这一有着广泛应用的领域。学习核磁共振波谱理论和学信号处理理论一样，让人由衷地惊叹造化赋予人的创造力之神奇。一个在形式上有着简洁与对称之美的数学变换方法，竟然能够在实验科学领域大显身手， Ernst 的工作堪称天才之作。 Ernst 的诺奖工作，是他于 1963 至 1966 年间在硅谷的 Varian 公司任职期间做出来的。这家公司由 Varian 兄弟创建于 1948 年，是硅谷最早的高科技公司之一。公司以制造电子真空管和医用直线加速器起家， 50 年代开始涉足核磁共振领域，因为拥有一批像 Ernst 这样锐意创新的科学家而成为核磁共振领域的领军公司。然而，在资本运作压倒技术创新的今天， Varian 于 2010 年不幸被 Agilent Technologies 并购。 2014 年， Agilent 领导层宣布关闭核磁共振谱仪的生产。一个曾经创造了神奇的高科技公司，在新的核磁共振技术依然层出不穷的年代却消失了，其命运令人扼腕。 Ernst 不仅是一位杰出的科学家，对艺术也有着广泛的兴趣和爱好。他年轻的时候曾痴迷于大提琴和作曲，后来又迷上了绘画。 1968 年的一次亚洲之旅，又让 Ernst 和唐卡画结下了不解之缘，他不仅开始收藏唐卡画，还利用学术休假的机会去北印度的一个小山村学习唐卡画。退休以后， Ernst 用诺贝尔奖金购置了一台拉曼谱仪，在家中搭建了一个工作台，开始研究唐卡画的颜料。上面这篇文章，发表在 2001 年瑞士化学学会的会刊 CHIMIA 上 (CHIMIA 2001;55:900-914) ，把他对唐卡画的研究心得娓娓道来。序言与结尾的两段话，也道出了他对科学与艺术的洞见，相信不少科学家伙也会有感同身受的体会。 There are indeed intimate relations between the arts and the sciences. Both fields require intuition and creativity, and in both fields greatness is measured by the mastery of inherent difficulties and nevertheless expressing eternal truths or achieving eternal beauty. For the author, art has been a constant source of inspiration in his professional research work. Perhaps art has contributed more than science to make our world hospitable and lovable, although science is of greatest importance for our survival. Together, in a creative symbiosis, they give us hope for a prosperous future in view of our physical and emotional well-being. Enrst 的工作很快使得核磁共振成为分析化学不可或缺的工具，有他的工作奠基，用核磁共振来解大分子——蛋白质——的结构，多多少少是意料中的事情。虽然蛋白分子结构的复杂性和有机小分子不可同日而语，这一难题还是被 Enrst 的同事 Kurt Wüthrich 给攻下了。在冷冻电镜成为结构生物学的新宠之前，核磁共振和 X 光晶体衍射在很长一段时间里平分着秋色，相比于 X 光晶体衍射，核磁共振无需生成蛋白晶体，因此在研究蛋白与分子间的作用及药物设计方面更具优势。 Wüthrich 的诺奖名至实归。 再下来，就是我如今赖以谋稻粱的医用核磁共振成像技术了，这个话题扯开了怕是刹不住车，还是先搁一搁，感兴趣的朋友可以去读我以前的一篇小文—— 理弦成像影憧憧 。 走过历史，为了是要面对现实和展望未来，科学网的博主在微信上发问了：“还有能再得奖的工作吗？”嗯，这个问题还真需要好好想想，现实离得太近，未免难以看得真切。不过要论及核磁共振成像对生命科学最重要的贡献，恐怕非脑功能成像 (fMRI) 莫属了。不为别的，人类对自身的好奇心由来已久，古希腊老头纸们发天问的时候，就已经想给这个问题寻找答案了。可是一直到了 100多 年前，脑洞大开的意大利生理学家 Angelo Mosso 才发明出了下面这个高端设备。他的假设是：人类一思考，血液就会涌向脑袋。 Mosso 的假设很大胆，然而它的求证却花了近 100 年的时间。最初是用正电子断层扫描 (PET) ，但直到有了 fMRI ，脑功能和脑图谱的研究才开始呈星火燎原之势。神经科学领域近二三十年来加速度般的发展， fMRI 功不可没。和这段历史平行的，是中国的改革开放，许多学子走出国门，加入到对人类认知活动的研究中。下面这张照片，是《神经影像》杂志纪念 fMRI 研究 20 年的封面照片，有许多对这一领域做出了重要贡献的学者，从中可以一窥中国学人在世界舞台上的风采。 (from PA Bandettini, Twenty years of functional MRI: the science and the stories. NeuroImage 2012;62:575-588) 未来会是什么情形，我不太敢下结论。我一直不愿预测未来，一是觉得有扮巫婆之嫌，二是以严谨为标志的科学研究，其发展却每每超出了人的想象。下面的卡通来自微信群里的一位同仁，贴上来博看官一笑，当不得真。不过有一年大选年，还真有人试图用 fMRI 来偷窥摇摆不定的选民，引来《科学》杂志一篇谆谆的 editorial ，告诫人们： fMRI is not a crystal ball! （全文完）
纵向分量要回家，横向分量要散伙。回家的慢，散伙得快。 物理上说，在磁场方向，平衡时候是有波尔兹曼分布，所以任何偏离平衡的情况，最后都要回到平衡，这个过程一般在100ms 到10s左右， x,y方向，自旋的相互关联最后要消失的，如同酒店墙上的很多钟表，最后时刻都是差别很大，没有关联的，这个过程大概在ms左右。 最后说一句，性质上，这个方程是维象方程，也就是说，从实验总结的，任何人愿意的话，都可以提出其他的形式来解释你自己的现象，如果能够解释的更好的话。 核磁共振布洛赫方程的稳态解与非稳态解 布洛赫方程是经典力学描述核磁共振现象最为重要的理论基础之一，是理解和做好核磁共振实验的必备知识。Das 曾用laplace变换求其解析解，但由于计算工具的限制，求取完整的解析解十分困难，以至于许多人不得不用数值方法求解布洛赫方程 NMR: Kinetics We have highlighted your search term bloch-mcconnell方程 for you. If you'd like to remove the search term, click here . Nuclear magnetic resonance (NMR) is an analytical technique used in chemistry to help identify chemical compounds, obtain information on the geometry and orientation of molecules, as well as to study chemical equilibrium of species undergoing physical changes of composition, among many others. Capitalizing on the ability to manipulate the magnetization through different pulse programs in NMR, allows for the study and understanding of the kinetics of a system. The exchange rates between two sites can be evaluated through dynamic nuclear magnetic resonance experiments (DNMR). 17 O is a common, NMR active nucleus that is used in the study of kinetics. 1. Introduction 2. 17O NMR for Kinetics Studies 2.1. Background and Equations 2.2. Bloch-McConnell Equations for Metal Site (Equations 1-3) 2.3. Bloch-McConnell Equations for Bulk Water Site (Equations 4-6) 2.4. Experiments 2.4.1. T2 Studies 2.4.2. T1 Studies 3. NMR Kinetic Studies 4. References 5. Outside Links 6. Problems 7. Solutions Introduction NMR uses radio frequency radiation to change the direction of nuclear spins that have been placed in a static magnetic field, and measures the change of magnetization as a function of time. Since its discovery, NMR has gone through many advancements that have enabled it to become a very useful analytical technique. The Fourier Transform NMR has enabled more complicated studies through the ability to create pulse programs that can manipulate the spectra, like saturate one species magnetization so no peak is produced. These pulse programs can also be used to tip the spin of certain nuclei, while keeping others along the z-axis. This is useful for many applications, including being able to quench signals, change the direction (positive or negative) of the signal, and track relaxation, to name a few examples. Using different pulse programs allows for the study of exchange rates between species. This is done by monitoring the changes in the environment of the NMR active nuclei as a result exchange between the sites. Because of the exchange, spins (magnetization) will be transferred, leading to changes in the bulk magnetization at both sites. Any NMR active nuclei can be used to study exchange rates, such as 13 C, 1 H, 17 O, but 17 O kinetic studies are often performed. This is done because 17 O enriched water can be used as one of the exchange sites, normally the bulk solvent site. 17 O NMR for Kinetics Studies Background and Equations Oxygen seventeen nuclei have a spin state of 5/2, making them susceptible to nuclear magnetic resonance. This isotope of oxygen is only 0.0373% naturally abundant, but using isotopically labeled oxygen compounds can result in useful information. Studying these nuclei in the presence of a magnetic field will provide information about the structure and environment of the oxygens in the molecule. Using dynamic NMR or DNMR, 17 O NMR experiments can be performed to understand chemical reactivity and kinetics of compounds. DNMR studies the effect of a chemical exchange between two sites that have either a different chemical shift or coupling constant. These studies are done by obtaining NMR spectra over time and analyzing the increase and/or decrease of the signals. Unlike other methods that are used to study kinetics, NMR studies can acquire information about the effects of the exchange on the molecules. To utilize NMR spectra to establish kinetic information, the Bloch equations must be adapted to include terms that take into account relaxation as a result of chemical reactivity. While investigating exchange reaction of 17 O water between two sites, the bulk water and water bound to a metal, it is assumed that the kinetics are 1 st order, such that: d u M d t = − k → M u M + k ← W u W d u W d t = − k ← W u W + k → M u M Where k ⃗ M k ⃗ W represent the rate of exchange between the bulk water and the bound water. These two sites can be said to be coupled because the isotopically enriched oxygen is exchanging between the metal site and bulk water site. As exchange occurs, the magnetization of the 17 O metal ensemble and 17 O water ensemble will change, not only due to magnetization relaxation, but also due to the exchange. The exchange rate terms can be added into the Bloch equations to take into account the relaxation. With the addition of this term, the equations are known as the Bloch-McConnell equations. Since there are two sites and three Bloch equations per site, there is a total of six equations for the change in magnetization of the system. Equations 1-3 are for the metal site, while Equations 4-6 are for the bulk water site. Bloch-McConnell Equations for Metal Site (Equations 1-3) d u M d t = v M ( ω r f − ω o ) − u M T 2 M − k → M u M + k ← W u W d v M d t = − u M ( ω r f − ω o ) − v M T 2 M − k → M v M + k ← W v W d m z M d t = v M ω 1 − ( m z M − m o ) T 1 M − k → M m z M + k ← W m z W Bloch-McConnell Equations for Bulk Water Site (Equations 4-6) d f r a c d u W d t = v W ( ω r f − ω o ) − u W T 2 W − k ← W u W + k → M u M d f r a c d v W d t = − u W ( ω r f − ω o ) − v W T 2 W − k ← W v W + k → M v M d f r a c d m z W d t = v W ω 1 − ( m z M − m o ) T 1 W − k ← W m z W + k → M m z M To analyze the NMR spectra, which is obtained by measuring the magnetization in the x-y plane, requires an equation that explains the magnetization change in the x-y plane as a function of time. In the rotating frame, the total magnetization in the x-y plane is comprised of two components the “real” and “imaginary” parts. Therefore, the total magnetization in the x-y plane can be expressed m x y = u + i v , or u = m x t − i v . Taking the derivative of this equation with respect to time leads to d m x y d t = d u d t + i d v d t . Using the previous relationships, the Bloch equations for the two sites can be simplified and rearranged to give the magnetization in the x-y place as a function of time. Invoking the law of detailed balance, which states that the exchange rate of the metal site times the amount of 17 O at this site is equal to the exchange rate of the bulk water site times the amount of 17 O at this site, will eliminate one of the rate coefficients, simplifying the equations even further gives Equation 7 . Equation 7: d = − where, L ¯ = R ¯ = k ¯ = L ¯ is the difference in the chemical shifts of the two sites signals, R ¯ is the relaxation in magnetization at each site without exchange, and k ¯ is the rate coefficients for the exchange. Taking the derivative of the equation, the magnetization of the bulk water signal and the magnetization of the metal site as a function of time results in Equation 8 . Equation 8: = e − t The m o x y is the initial magnetization along the x-y plane before relaxation. Using the Bloch-McConnell equation, the width and intensities of the peaks in the spectra become a function of the chemical exchange. By studying the change in the two peaks, the rate coefficients can be determined, which can be used to calculate other thermodynamic properties like entropy and enthalpy. Experiments T 2 Studies The most common way of studying chemical kinetics in NMR has been through the bandshape technique, which studies the change in the signals of the spectra as a result of exchange kinetics. Before any exchange occurs, two sharp signals are present, one for each of the two 17 O sites. As the exchange rate speeds up, the two peaks will begin to broaden and overlap. At an extremely fast exchange rate, the peaks will coalesce and be centered at the weighted average of the Larmor frequency of the bulk water and the bound water. This occurs because the two exchange sites will have two distinct peaks at slow exchange rates because the NMR active exchange species will be at each site for long enough time that detection of two separate sites will occur. As the exchange rate increases, the nucleus will be exchanging so quickly that the detection of the nucleus on either site becomes averaged out, creating one signal in the spectra. Figure 1 : Coalescing Peaks This figure shows the two peaks moving closer together and then coalescing as the exchange rate increases. The figure above shows peaks from a two-site exchange. The top spectrum depicts a slow exchange rate. As they move down, the rate constants are getting increasingly larger until the peaks coalesce. The width of the band at half height, or the full width at half max (FWHM) is used to track the rate coefficients of the exchange because it is proportional to both T 2 relaxation and the rate coefficient. During exchange rate experiments, Equation 9 can be used to calculate the exchange rate ( k ), which can then be used to determine other activation parameters such as Gibb's free energy, entropy, and enthalpy. Equation 9: k = π δ v 2 2 ( ω ∗ − ω o ) Swift and Connick used bandshape experiments to study the exchange of water from the bulk to a paramagnetic metal. They developed an equation that relates the band width of the signal to the mole fraction of each water site, the bulk P W and the metal P M . Equation 10 is the simplified Swift-Connick equation for the change in the paramagnetic water signal. ( Δ w is the change in the full width measured at half height) Equation 10: 1 P M ( Δ w ) = Δ w + Δ w 2 k 2 M By obtaining the NMR spectra and measuring the signal width, the exchange rate can be calculated. It can be seen that the peak broadness is a function of the T 2 M relaxation, or the transverse relaxation. It can be evaluated from the free-induction decay (FID). The FID is the time-domain signal of each frequency component. Each component results in a sine wave, which are then added together for the FID signal. At time zero, all the components are aligned, and over time they spread out and combine in a deconstructive manner, resulting in a decay of the total FID signal. This is an exponential decay and can be used to calculate the transverse relaxation with Equation 11 . Equation 11: M x y ( t ) = M o e − t T 2 The FID is obtained by using a simple π 2 pulse directed along the x-axis to tip the magnetization into the y-axis so it is processing in the x-y plane. The magnetization in the x-y plane is detected over time as the different frequency components process at different rates. This will result in the FID so T 2 M can be found. T 1 Studies A second method of observing the magnetization exchange between bulk solvent and the metal is by studying the \T_{1}\)relaxation. This method is completed by observing the intensity of one site's signal, while the other signal is saturated by the applied radio frequency pulse program. As the saturated site's spin is transferred to the second exchange site, the second site's magnetization intensity increases as result of the additional spin, while the saturated site's magnetization decreases. From the Bloch equations, the relaxation of magnetization in the z-axis is proportional to 1 T 1 M . Studying the T 1 relaxation tracks the magnetization change between the metal and bulk site through an inversion-recovery NMR experiment. This experiment is done using a two-pulse pulse sequence. A 180 o shape pulse with a radio frequency close to the bulk solvent's Larmor frequency is directed at the sample. Since a shape pulse is a selective pulse, it will only flip the magnetization of the bulk solvent. The solvent’s magnetization, having been flipped 180 degrees, will be aligned opposed to the applied magnetic field. Once probed, the magnetization will begin to relax along the z-axis until it reaches it equilibrium position. After some time (t), a 90 o square pulse is applied. A square pulse is not selective and excites a broader range of frequencies, resulting in both the metal and solvent magnetizations to be tipped into the x-y plane to be detected. At time zero, the magnetization signal for the solvent will be large and negative because it will tipped into the x-y plane in the negative direction. Figure 2: Magnetization as a result of the pulse program The bulk solvent magnetization is tipped to be against the static magnetic field, while the metal site magnetization remains inline with the static magnetic field. Then the short 90 0 pulse is applied to tip both site's magnetizations into the x-y plane for detection. The bulk solvent magnetization will result in a negative signal, and the metal site magnetization will be positive. As exchange occurs, the magnetization along the z-axis will become positive because of natural relaxation, and because the 17 O from the metal will be positively in the z-direction, helping speed up the relaxation. This can be tracked by varying the time between the 180 o and 90 o pulse, since the direction (positive or negative) and intensity of the peaks will change. Figure 3: Magnetization along z-axis The magnetization of the bulk water site, directed against the static magnetic field, will begin to relax back towards the initial condition (all magnetization direct with the static magnetic field). The relaxation will cause the the bulk water site's negative signal to decrease in size and then become positive as the oxygen on the metal site exchange. The above image shows that at t=0 the solvent peak is large and negative, since no magnetization will have had time to relax. Between t=1 and t=2, the magnetization along the z-axis has inverted back, and will produce a positive peak. The exponential line from the first negative peak to the last positive peak results in Equation 12. Equation 12: M z ( t ) = M o ( 1 − e t T 1 ) Figure 4: T 1 equation representation As the magnetization relaxes along the z-axis, it relaxes exponentially with Equation 12 T 1 can then be used to calculate the exchange rate through the Bloch-McConnell equations. A plot of the intensity of magnetization as a function of time would look like: Figure 5: Plot of intensity versus time for the bulk solvent site magnetization These are just two pulse sequences that can be used to study kinetics through NMR. More intricate pulse sequences can be used to perform kinetic studies on more complex systems. NMR Kinetic Studies NMR studies have been carried out to understand the kinetics water exchange with different compounds as a function of temperature and pressure. There also have been experiments that track the affects of pH on the exchange rates of chemical systems. Below is a list of some journal articles containing dynamic NMR experiments with 17 O. A quick search on DNMR experiments will produce many journal articles that have been published over the years. Phillips, Brian L., Susan Neugebauer Crawford, and William H. Casey. "Rate of water exchange between Al(C 2 O 4 )(H 2 O)4+(aq) complexes and aqueous solutions determined by 17O-NMR spectroscopy." Geochimica et Cosmochimica Acta 61.23 (1997): 4965-4973. Szab, Zolt N., Ingmar Grenthe. "On the mechanism of oxygen exchange between Uranyl(VI) Oxygen and water in strongly alkaline solution as studied by 17O NMR magnetization transfer." Inorganic Chemistry 49.11 (2010): 4928-4933. References Sandström, J. (1982). Dynamic NMR spectroscopy . London: Academic Press. H. M. McConnell, Journal of Chemical Physics 1958 , 28 , 430. T. J. Swift, G. M. Anderson, R. E. Connick, M. Yoshimine, Journal of Chemical Physics 1964 , 41 , 2553. T. J. Swift, R. E. Connick, Journal of Chemical Physics 1962 , 37 , 307. Outside Links http://en.wikipedia.org/wiki/Nuclear_magnetic_resonance Pulse Sequence Library: http://nmrwiki.org/wiki/index.php?title=Special:PulseSequenceDatabase FID: http://en.wikipedia.org/wiki/Free_induction_decay Problems Describe the difference between the T 1 and T 2 relaxation. Why are the Bloch-McConnell equations needed for kinetic NMR studies? Describe what would happen in an inversion-recovery experiment if the signals from the solvent and metal site occur at similar frequencies? What problems can arise from using the Swift-Connick equation and the bandshape technique? Draw the pulse sequence of the inversion-recovery experiment. (A schematic of the frequency versus time) Solutions The T 1 relaxation is relaxation of the magnetization in the z-axis and is known as longitudinal relaxation. The T 2 relaxation is relaxation in the x and y axis, or xy plane. It is known as transverse relaxation. The Bloch-McConnell equations are the extension to the Bloch equation. They include an extra term that takes into account exchange between two species. Without this relationship, kinetic studies would not be able to be studied using NMR. If the signals are too close together, the 180 degree shape pulse would flip both magnetizations, not separating the two to allow for analysis. More intricate pulse sequences can be used with more pulses to obtain the magnetizations in opposite directions along the xy plane. NMR signals are often small since its a very insensitive technique. Peaks can not only be easily lost in the noise, but the bandwidth may be extremely difficult to determine, making the Swift-Connick equation hard to use. Pulse sequence drawing for the inversion-recovery experiment
去盐湖城开会，犯懒，没带兔子。早上拉开旅馆房间的窗帘，见旭日在远处雪山的峰顶变幻着颜色，当时一个“悔”字涌上心头。 开会间偶然得到了个蹭车的机会，跟同事去了几处最漂亮的滑雪胜地。虽然已是暮春，满目仍是一片银白的童话世界，在高原直射的阳光下晶莹透亮。当时的心情：后悔大发了！ 晚上在犹他大学的体育馆参加一个活动，馆外就是冬奥会的冰场。两边落地窗的大厅，一面是日落盐湖，另一面是月出关山。当时……嗨！不提了，肠子都悔青了。 还是上两张同事拿全幅单反给拍的片子吧。 身边的这块牌子，赫然题着“通往锡安之路”（ The Road to Zion ），勾起了我的好奇心。 锡安，即锡安山（ Mount Zion ），所罗门圣殿的所在地，为犹太教圣地。公元前 586 年，所罗门圣殿毁于巴比伦人之手，希伯来人也因此沦为巴比伦之囚。“锡安”因此成了一个象征——异乡犹太人心目中神圣甜美的家园。《旧约·诗篇》第 137 章开篇这样悲叹道： By the rivers of Babylon we sat and wept when we remembered Zion. There on the poplars we hung our harps, for there our captors asked us for songs, our tormentors demanded songs of joy; they said, Sing us one of the songs of Zion! How can we sing the songs of the Lord while in a foreign land? 这段历史后来被威尔第改编成了歌剧，里面有一首著名的“希伯来奴隶合唱曲”，又名“飞吧！思想，乘着金色的翅膀”。歌中所表达的对家园的渴望是那样的真挚深切，在当时正谋求统一的意大利民众心中产生了强大的共鸣，以至于有人提议，要以它来作为统一后的意大利国歌。 大都会歌剧院演唱的“飞吧！思想，乘着金色的翅膀” 无独有偶，丧失了家园、被贩卖到美洲的黑奴们，也是唱着这样的歌来表达对故园的渴望与思念的。八十年代被成方圆唱红了大江南北的“巴比伦河”，几乎就是《旧约·诗篇》的逐字翻唱。锡安，成了精神家园的象征。 “巴比伦河” 而我身边的这块牌子，和犹太人、意大利人、黑奴都没有关系，它讲述了一段摩门教徒寻找家园的故事。创建于 19 世纪初的摩门教，因不能见容于传统的基督教，先是从东部被逼到了中西部，与那里的基督徒依然纷争频仍，在经历了“密苏里战争”、“伊利诺战争”后，被迫大规模地向更加地广人稀的西部迁徙。他们把这次迁徙看作是寻找家园的行动， the Road to Zion. 巧合的是，那时流离在欧洲的犹太人正在搞犹太复国运动，他们打出的口号是： Return to Zion. 犹太复国主义因此被称作是 Zionism. 只不过犹太人重返家园的旅途比摩门教徒要更加艰辛与坎坷。 通往锡安之路 迁徙途中的摩门教徒 摩门教徒们把这次西迁自比作犹太人出埃及，杨百翰是西迁的领导者，因此被称作是摩门教的摩西。 教徒们甫一在盐湖山谷落脚，杨百翰就提出了要在这高原的大荒川里营建一座圣殿。盐湖城附近的大山有不少是花岗岩材质的，于是教徒们开始了劈山造圣殿的工程。 摩门圣殿 圣殿旁的礼拜堂 耶稣受洗 渔夫彼得接受耶稣的感召 布道的耶稣 圣殿广场 圣殿广场一角 之所以带了个小 DC ，是为了开会时拍 poster 方便。我听报告时不太爱拍照，觉得比较扰民。不过听到有趣的段子时，还是忍不住要掏相机，好在这样的时候不多。 年会每年都以 Lauterbur Lecture 开场。 Lauterbur 是核磁共振成像技术的发明者，也是我们学会的创建者和第一任主席。 Lauterbur Lecture 始于 2002 年在夏威夷举行的年会，由 Lauterbur 本人作第一位演讲者。那年的 Lauterbur 已是 73 岁高龄， 他在演讲中详述了核磁共振成像技术发明的过程。从 Lauterbur 走上讲台到结束时离开讲台，两次全场起立，大家以长时间的鼓掌向这位老人表示敬意。次年， Lauterbur 和 Mansfield 共同获得诺贝尔医学奖。 Lauterbur Lecture 的开场白自然要和 Lauterbur 挂钩，今年的演讲者扯得更远，从 Ernst 的书开始讲起。 Ernst 是 1991 年诺贝尔化学奖得主，他与人合著的“ Principles of Nuclear Magnetic Resonance in One and Two Dimensions ”是经典。虽然里面涉及量子力学的内容我已经看不懂了，但这本书至今仍在我的书架上放着，有二十多年了。 Ernst 这本书的最后一章提到了核磁共振成像，相对于核磁共振谱仪在分析化学中的应用，核磁共振成像的概念很晚才被提出来。原因并不奇怪：电磁波成像的分辨率取决于波长，核磁共振辐射的是无线电波，波长比可见光的微米波段和 X 光的安米波段要长出许多。比如 100 兆赫的无线电波，波长有 3 米，见了大象都能绕过去。要是用无线电波的照相机给大象拍照，出来的结果肯定是“大象无形”。 Ernst 谈“大象无形” 然而 Lauterbur 偏偏不信这个邪，不但如此，在大家都在为提高核磁共振的灵敏度而努力，要把磁场调得均匀更均匀时，他偏偏要加上一个梯度磁场，把磁场变得哪儿跟哪儿都不一样，让一大堆原子核呕哑嘲哳地唱歌儿，发出不同的频率。这样做的结果如何呢？哈哈，大象现原形了！岂止是大象，现在的核磁共振技术，把分辨率做到 100 微米也是完全有可能的，能够看到细微的脑血管。 Lauterbur 让大象“原形毕露” 唉!写基金、审基金的季节又开始了，我打算休博数月了。 祝大家劳动节、青年节、儿童节、建党节、建军节快乐！家有小朋友的母亲节、父亲节快乐！
首先要感谢余昕老师推荐了一个非常实用的网络教程‘the basic of the NMR',解决了我在初期实验和科普（导师推荐读the spin dynamics一书)过程中遇到的几点困惑。其次，要感谢导师对我这个新手的耐心指导，让我在未知领域爬行过程中多了一份信心。 我要攻克的课题第一步是测量高温自扩散系数。利用自旋回升方法在恒定梯度的磁场中测量在不同脉冲间隔时间的回声强度，扩散系数可以通过解指数方程得到。在测量过程中，不仅要掌握测量的方法，更应该理解其中的物理机制以便解释扩散结果。其中最基本的物理机制就是扩散导致的相差（降低了自旋回升的强度）。将自旋相差看做是一个高斯分布。。。
当我平躺在手推车上，视野里只有天花板那么一小片地方，而那一块地方，毫无色彩，以此为参照，似乎你一直就没有动过。周围也变得静寂，从病房到电梯，平时几步就走过去的路程，似乎也走了很久。 我突然意识到，我到底是不是癌其实已经确定了，这一刀切下去，答案就完全公开了，而之前所做的种种推想，科学的，或者不科学学的，科学的，比方穿刺，比方钼靶，比方核磁共振；不科学的，比方从医生的神态，语气等等进行的判断，那种从网上所查找的病例，朋友们为安慰我而说的种种虚惊，甚至那种神秘的预感等等等等，而我从这些林林总总中所推测的好的结论，都会在此面前不堪一击，近一个月来的种种挣扎都毫无意义，就如同面对一个无可避免的失败，想起我们曾经为了挽回这个结局曾经所做过的种种徒劳的挣扎，我们会感到多么的痛心，无望和无助......而我基于良好的愿望基础上所做的种种假设，在事实面前，又是如此无力！想到此，一滴清泪从眼角溢出，流过太阳穴，滴到了手推车上，接着，有一滴......医生俯下身来，轻声问一句，紧张了？一会麻药一打，你就像睡着一样，醒来手术就做好了。 我其实不紧张，我只是做好了准备，准备接受一直被我掩盖着的事实。那天是6月5日，我最后一天可以不把自己作为癌症病人，尽管当时我是，或许已经是了很久了。无论如何，此刻，在心理上，我还在癌的这边，和大多数人一样，可以尽享平常的好处，可以抗争，可以奋斗，可以无所顾忌，而做了手术，我可能就到那一边了，Cancer has a way of issuing patients a sudden ticket to the world of otherness。 手术室没有腾出来，我被推到墙角，有几个医护人员在哪儿谈笑风生，所有有关病情的种种，似乎丝毫没有影响到他们的情绪；另一个手推车被推到我身边，手推车上的是个男人，和我并行着躺着，有点同床共枕的感觉，问他什么问题，他说他打呼，大概是晚上想和爱人睡在一起，又不至于影响爱人睡眠的贴心丈夫。而我那种生死攸关的感觉，在这个空间里格格不入，我应该也只是在此一游的过客，所等待着的，不是那个决定生死的手术，而是看个风景，解个风情。然后，走向新的彼岸...... 当我被推到手术室，推我进来的人告诉里面的人说，病人有点紧张，一群小姑娘便叽叽喳喳地把我从手推车上扶到麻醉台上，脱我的衣服，吩咐我伸开手臂，一个很和善的小姑娘把一个塑料罩子放到我鼻子上，说让我数一二三，数到十，如果想睡觉就睡。我很听话地数着，没有到十，我就失去知觉了。 等我醒来，一个人告诉我手术已经做完，其间发生的种种事情，我毫无感觉，这段时间，我把生命的支配权让渡给了大夫。按照医生先前的告知，我知道其间有好几根管子从我的嘴里插到心肺等处，以便于维持我最基本的生命体征。而这些我都一无所知，脑子里唯一的概念是：我是否是癌症？等医生把我折腾到病床上，我命令老公看看我的腋窝有伤口没有？ 老公说有纱布包着，看不到。他不敢扯开看，可能有伤口，否则干嘛要包纱布。而我还在挣扎着要那么一个希望，希望那里没有伤口，这样，当我手术刀口愈合，我就可以回家，重新开始生活了。第二天，医生撤了氧气瓶之类的，把我的护理也从一级护理改为二级，我以为这可能是医生们给的信号，起码证明我的病情不是很重，就大着胆子问那个和他谈手术问题的医生：我不是癌吧？ “是癌，是浸润癌，都已经不是原位癌了。” 这些天为了证明我不是癌而恶补的有关肿瘤学知识，恰好让我知道，癌在我的身体里已经完成了它的整个演变过程，正准备蚕食我的生命呢。那天无意间从乳房下面那么一抹，手指就触摸到一个肿块，而这个肿块，竟然就是那个能把我小命要走的癌！那天是5月10日，晚上，有点热，坐在电脑跟前，我把衣服解开了，手下意识地从下往上滑过，感觉乳房下面有点硬，当时便有点不详的预感，而终于，预感成真，而这，也太让人不可思议了：死亡，就这么触手可及么？
美国纽约大学、纽约州立大学石溪分校和英国剑桥大学的研究人员开发出基于核磁共振成像（MRI）方法的锂电池内部检测技术，可为电池内部运作提供诊断服务，提高电池性能和安全性。相关研究成果发表在《自然—材料学》上。 锂电池充电时，锂纤维会附着在锂电池内部的碳电极上，会导致电池短路、过热着火，甚至爆炸。研究人员可利用该方法扫描分析锂电池内部的化学成分，消除隐患。。 核磁共振成像技术属于非侵入性技术，可以提供电池内部的微观结构，可视化电极表面上的微小变化。电解质和电极表面都可以使用这种可视化技术，提供了全面了解电池性能的变化进程。研究人员将进一步研究高清晰成像、成像时间更短的技术和方法，最终使电池更轻、更安全、更灵活。 该方法还可用于研究材料表面的不规则行为和裂缝，还可评估其他电化学设备，如燃料电池。该研究得到了美国能源部和美国国家科学基金会的资助。 7 Li MRI of Li batteries reveals location of microstructural lithium There is an ever-increasing need for advanced batteries for portable electronics, to power electric vehicles and to facilitate the distribution and storage of energy derived from renewable energy sources The increasing demands on batteries and other electrochemical devices have spurred research into the development of new electrode materials that could lead to better performance and lower cost (increased capacity, stability and cycle life, and safety). These developments have, in turn, given rise to a vigorous search for the development of robust and reliable diagnostic tools to monitor and analyse battery performance, where possible,in situ. Yet, a proven, convenient and non-invasive technology, with an ability to image in three dimensions the chemical changes that occur inside a full battery as it cycles, has yet to emerge. Here we demonstrate techniques based on magnetic resonance imaging, which enable a completely non-invasive visualization and characterization of the changes that occur on battery electrodes and in the electrolyte. The current application focuses on lithium-metal batteries and the observation of electrode microstructure build-up as a result of charging. The methods developed here will be highly valuable in the quest for enhanced battery performance and in the evaluation of other electrochemical devices. http://www.nature.com/nmat/journal/v11/n4/full/nmat3246.html#affil-auth
The lipoprotein subfraction profile: heritability and identification of quantitative trait loci Abstract The HDL and LDL subclass profile is an emerging cardiovascular risk factor. Yet, the biological and genetic mechanisms controlling the lipoprotein subclass distribution are unclear. Therefore, we aimed 1) to determine the heritability of the entire spectrum of LDL and HDL subclass features and 2) to identify gene loci influencing the lipoprotein subfraction pattern. Using NMR spectroscopy, we analyzed the lipoprotein subclass distribution in 1,275 coronary artery disease patients derived from the Regensburg Myocardial Infarction Family Study. We calculated heritabilities, performed a microsatellite genome scan, and calculated linkage. HDL and LDL subclass profiles showed heritabilities ranging from 23% to 67% (all P 10(-3)) of traits using univariate calculation. After multivariate adjustment, we found heritabilities of 27-48% (all P 0.05) for HDL and 21-44% for LDL traits. The linkage analysis revealed a significant logarithm of the odds (LOD) score (3.3) for HDL particle concentration on chromosome 18 and a highly suggestive signal for HDL particle size on chromosome 12 (2.9). After multivariate adjustment, we found a significant maximum LOD score of 3.7 for HDL size. Our study is the first to analyze heritability and linkage for the entire spectrum of LDL and HDL subclass features. Our findings may lead to the identification of genes controlling the lipoprotein subclass distribution.
催化基础国家重点实验室纳米和界面催化研究组（502组）受邀撰写的综述文章“In situ solid-state NMR for heterogeneous catalysis: a joint experimental and theoretical approach”在近期出版的Chemical Society Reviews上发表（Chem. Soc. Rev., 2012, 41, 192-210），影响因子26.585。 文章综述了近十年来该研究组利用原位固体核磁共振技术在多相催化领域取得的重要进展。文章介绍了原位固体核磁共振方法及其在酸性表征、催化反应机理和反应动力学中的应用，强调了实验结合理论计算在确定反应中间体结构及反应机理研究中的重要作用。 近年来，该研究组致力于发展原位固体核磁共振方法以及核磁共振信号灵敏度增强技术，在催化反应及材料表征领域取得了一些重要成果。例如，与美国西北太平洋国家实验室合作，利用高场95Mo NMR（21.1 Tesla）研究了甲烷芳构化反应中碳化钼活性物种。相关结果发表在《美国化学会志》（J. Am. Chem. Soc., 130（2008）3722-3723）；在自行研制的一套与固体核磁共振仪耦合的动态催化反应系统中，采用激光诱导超极化129Xe技术，首次在模拟催化反应条件下直接观察到了甲醇分子在孔径为0.8nm的CHA分子筛孔道扩散和脱水过程，并精确获得了分子扩散和反应的动力学参数。相关方法和实验结果以研究论文形式（Article）发表在《美国化学会志》（J. Am. Chem. Soc., 131（2009）13722-13727），被认为是“一种对纳米孔催化反应研究具有重要意义”的发明。 此外，该研究组一直致力于基础催化与应用催化的结合。与低碳烃综合利用及沸石催化材料研究组（DNL0804组）合作利用固体核磁共振技术深入研究了烯烃歧化反应以及共结晶分子筛的结构。相关工作分别发表在J. Catal.，J. Phys. Chem. C等刊物。与甲烷及低碳烃转化新催化过程研究组（DNL0802组）合作在离子液合成分子筛领域也取得了重要进展，相关工作发表在Chem. Eur. J., Phys. Chem. Chem. Phys.等刊物。 In situ solid-state NMR for heterogeneous catalysis: a joint experimental and theoretical approach Weiping Zhang, Shutao Xu, Xiuwen Han and Xinhe Bao Chem. Soc. Rev., 2012, 41, 192-210 DOI: 10.1039/C1CS15009J Received 10 Jan 2011, First published on the web 11 Jul 2011 Abstract In situ solid-state NMR is a well-established tool for investigations of the structures of the adsorbed reactants, intermediates and products on the surface of solid catalysts. The techniques allow identifications of both the active sites such as acidic sites and reaction processes after introduction of adsorbates and reactants inside an NMR rotor under magic angle spinning (MAS). The in situ solid-state NMR studies of the reactions can be achieved in two ways, i.e. under batch-like or continuous-flow conditions. The former technique is low cost and accessible to the commercial instrument while the latter one is close to the real catalytic reactions on the solids. This critical review describes the research progress on the in situ solid-state NMR techniques and the applications in heterogeneous catalysis under batch-like and continuous-flow conditions in recent years. Some typical probe molecules are summarized here to detect the Brønsted and Lewis acidic sites by MAS NMR. The catalytic reactions discussed in this review include methane aromatization, olefin selective oxidation and olefin metathesis on the metal oxide-containing zeolites. With combining the in situ MAS NMR spectroscopy and the density functional theoretical (DFT) calculations, the intermediates on the catalyst can be identified, and the reaction mechanism is revealed. Reaction kinetic analysis in the nanospace instead of in the bulk state can also be performed by employing laser-enhanced MAS NMR techniques in the in situ flow mode (163 references). http://pubs.rsc.org/en/Content/ArticleLanding/2012/CS/c1cs15009j
几年前曾见过明杰，人非常的nice，思维非常的活跃。2011年中国科学院院士增选结果终于公布了，发现明杰终于修成正果，十分高兴，也为核磁共振界再增加一名院士而高兴。核磁共振领域目前有三位著名的院士：叶朝辉院士，施蕴瑜院士和张明杰院士，对于前面二老，不用多说大家都很熟悉，现在对明杰做一个详细介绍！ 2011年度中国科学院新增院士张明杰 张明杰，浙江宁波人，毕业于复旦大学，中国结构生物学家，现为香港科技大学生物化学系教授。他的主要研究方向是参与突触信号传导和细胞极性调控过程的各类复合物的构架、组装、转运等的分子机制；主要研究手段包括X射线晶体学和NMR。他所领导完成的“构建神经系统信号传导复合体的结构基础”项目获得2006年度国家自然科学奖二等奖。他也是中国科学院海外评审専家（2005年）之一。他与其团体在有关肌动蛋白7a的突变如何导致先天性失聪及失明的研究刊载于顶尖学术期刊科学上。2011年12月9日，当选中国科学院院士。 学历 1988年，复旦大学化学专业学士学位 1993年，卡尔加里大学生物化学博士学位 获奖情况 2002年，海外杰出青年基金奖 2003年，裘搓基金会裘搓研究员奖（Croucher Foundation Senior Research Fellow Award） 2006年，国家自然科学奖二等奖 学术交流等情况 在开展NMR研究的过程中，与中国科学院武汉物理与数学研究所一直保持着密切的合作关系。 2003年10月参加了中国分析测试协会(CAIA)主办北京分析测试学术报告会及展览会(BCEIA)，2004年6月参加了武汉物理与数学所举办的“第二届磁共振新技术——生物大分子NMR国际研讨会”。 主要学术贡献创新思想 张明杰博士主要从事结构生物学，生物化学及其分子生物学的研究。他的调控神经细胞信号传递的蛋白质的结构和功能的研究成果，对于治疗神经系统衰退的疾病，如中风及老年痴呆症等，有着极为重要的影响。张教授及其研究小组运用核磁共振技术，从传统中药中筛选活跃分子，抑制神经信号传递中的一氧化氮合成，以发掘具潜质的药物先导化合物，治疗中风疾病。 1998年利用核磁共振技术解出神经元一氧化氮合成酶的一个抑制蛋白的三维结构，次年又解出神经元一氧化氮合成酶一个重要区域与另一种蛋白形成的复合物的三维结构，一氧化氮合成酶含有的PDZ结构域在许多蛋白质相互作用中起重要作用，解出这个区域与其他蛋白结合的结构，对于生物化学领域有着重要的意义。 2001年与其他生物学专家紧密合作，在细胞生物学方面取得重大突破，首次破解了一种对于确保细胞正常运作至关重要的蛋白质(Ykt6p)的三维结构与功能之间的关系。 曾获得“裘槎优秀科研者奖”,以表扬他在材料科学及生物化学领域进行的基础研究及做出的贡献。 他的调控神经细胞信号传递及神经系统发育的一系列蛋白质的结构和功能的研究成果，对于治疗神经系统衰退的疾病，如中风及老年痴呆症等，有着极为重要的影响。近年来在Cell, Science,NatureStruct. Biol., Mol Cell, EMBO J., PNAS等杂志发表论文100余篇。仅2011年就发表了1篇Cell, 1篇Science， 2 篇Mol Cell, 1篇PNAS, 1篇EMBO J. 其培养的学生和博士后有很大一部分已经在世界各地建立了他们独立的研究组。 2011年张明杰实验室论文发表情况 Zhu, J., Shang, Y., Xia, C., Wang, W., Wen, W., and Zhang, M., ( 2011 ) "Guanylate Kinase Domains of the MAGUK Family Scaffold Proteins as Specific Phospho-Protein Binding Modules" EMBO J (In Press) Pan, L., Chen, J., Yu, J., Yu, H., and Zhang, M. ( 2011 ) "The Structure of the PDZ3-SH3-GuK Tandem of ZO-1 Suggests a Supramodular Organization of the MAGUK Family Scaffold Protein Core". J Biol Chem. 286, 40069-74 Lu, Q., Yu, J., Yan, J., Wei, Z., and Zhang, M. ( 2011 ) "Structural basis of the myosin X PH1N-PH2-PH1C tandem as a specific and acute cellular PI(3,4,5)P3 sensor " Mol. Biol. Cell ，accepted Wei, Z., Zheng, Z., Spangler, S A., Yu, C., Hoogenraad, C. C., and Zhang, M. ( 2011 ) "Liprin-mediated Large Signaling Complex Organization Revealed by the Liprin-α/CASK and Liprin-α/Liprin-β Complex Structures" Mol. Cell 43, 586-598 Zhu, J., Wen, W., Zheng, Z., Shang, S., Wei, Z., Xiao, Z., Pan, Z., Du, Q., Wang, W., and Zhang, M. ( 2011 ) "LGN/mInsc and LGN/NuMA Complex Structures Suggest Distinct Functions in Asymmetric Cell Division for the Par3/mInsc/LGN and Gαi/LGN/NuMA Pathways" Mol. Cell 43, 418-431 Liu, W., Wen W., Wei, Z., Yu, J., Ye, F., Liu, C-H., Hardie, R. C., and Zhang, M.( 2011 ) "The INAD scaffold is a dynamic, redox-regulated modulator of signalling in the Drosophila eye" Cell 145,1088-1101 Huo, L., Wen, W., Wang, R., K am, C., Xia, J., Feng, W., and Zhang, M.( 2011 ) "Cdc42-dependent formation of the ZO-1/MRCKb complex at the leading edge controls cell migration" EMBO J. 30, 665-678 Wei, Z., Yan, J., Pan, L. Lu, Q., and Zhang, M.( 2011 ) "Cargo Recognition Mechanism of Myosin X Revealed by the Structure of its Tail MyTH4-FERM Tandem in Complex with the DCC P3 Domain" PNAS 108, 3572-3577 Wu, L., Pan, L., Wei, Z., and Zhang, M.( 2011 ) "Structure of MyTH4-FERM Domains in Myosin VIIa Tail Bound to Cargo" Science 331,757-760
1944 年，瑞典皇家科学院决定恢复颁发因战争而中止了四年的诺贝尔奖，一番讨论之后，物理学奖给了拉比，以表彰他在核磁共振领域所作的开创性工作。当时战争仍在进行着，拉比无法前往斯德哥尔摩领奖，颁奖仪式只好改在纽约举行，由哥伦比亚大学的校长颁发。校长当时已经八十多岁了，老眼昏花，宣读贺词的时候从头到尾把拉比当作了费米。好在拉比当时心情愉快，也不计较。事后，有知情人告诉拉比，拉比之获奖，得到了费米的推荐。费米是为数不多的理论实验皆通的大师，对物理学有着独到而深刻的见解，能得到费米的赏识，令拉比颇感欣慰，这意味着这块奖章的含金量是很足的。到了 1982 年，为爱因斯坦作传的派斯又告诉拉比，他看到了爱因斯坦向诺奖委员会推荐拉比的信的原件。拉比当时已是 84 岁的耄耋老人了，听说此言喜出望外地说：“哇塞！一个诺奖让老夫得意了三回！” 大约两年前，我写过 奧本海默 ，里面的大部分内容，是我读《美国的普罗米修斯》一书所得。然而读奧本海默，在为奧本海默多舛的命运唏嘘之余，我却由衷地喜欢上了拉比。正好他开创的核磁共振领域，是我如今赖以谋稻粮的所在，读研究生的时候，也曾粗粗地读过他写的两能级系统一书。于是满怀崇敬地从学校图书馆借回了这本《拉比传——物理学家和公民》。 书我倒是很快就读完了，而且还读了不止一遍，但我的读后感却一直难产，原因是多方面的。这本书的作者 John S. Rigden 本人是学物理出身的，他在介绍拉比的学术成就时夹入了许多对物理学的评论和分析，不是我这个半路出家、对物理学一知半解的人能够完全理解的，因此写起来多了份畏缩感，总觉得应该读一些其他的书先把课给补上。那情形有些像替杂志审稿，若是撞上了一个我并不很熟悉的领域，总得要去读一些相关的背景文章，才敢放心地去写评论。 不过最主要的原因还是，拉比一生值得讲述的事情太多了。拉比和奧本海默虽然都同为犹太物理学家，而且几乎是同时代的，然而奧本海默出身于钟鸣鼎食之家，拉比则是从布鲁克林的犹太贫民窟中走出来的，他的父母是生活在社会底层、连英文都不会说的犹太移民，他本人也曾必须在追求物理学、还是养家糊口之间做出选择。拉比能从这样的家庭走向诺贝尔奖的领奖台，并打造出哥伦比亚物理系这样超一流的物理王国，靠的是非凡的智慧和对物理学的热爱与执着。 拉比也是一位社会活动的积极参与者。二战期间，拉比在 MIT 辐射实验室领导了雷达的研制，对盟军在欧洲战场的转败为胜起了举足轻重的作用。虽然他本人反对原子弹的研制，但他还是应奧本海默之邀和玻尔一道担任了曼哈顿计划的顾问。二战结束后，拉比在担任哥伦比亚物理系主任的同时，还一度出任杜鲁门的科学顾问，并且利用自己的影响四处奔走，创建了布鲁克海文国立实验室。拉比同时又是一位极富原则性、有着强烈的社会责任感的物理学家，他对于政治的卷入，也始终是以坚持原则为底线的。他在奧本海默听证会上出色的表现，以及事后在学术会议上拒绝同泰勒握手，读来酣畅淋漓，让我看到了一个个性鲜明、刚毅果敢的智者。 读这样一位巨人的传记，时常让我有想把全书逐句翻译出来的冲动。但以我现在的学识和文字功底，我自认尚无法胜任这项工作。所以决定折中一下，细水长流地挨章写写读后感。这篇文章，算是给这个系列做一个序。 此文的题目，是我在读完书中的第 16 章——拉比与奥本海默——时想到的，作者在罗列了拉比和奥本海默诸多的相似之处后，深入分析了造成二人迥然不同的终结命运的原因，并在该章的结尾引用了一首脍炙人口的童谣“ Humpty Dumpty ”作喻： Humpty Dumpty sat on a wall, Humpty Dumpty had a great fall. All the king's horses and all the king's men Couldn't put Humpty together again. 作者写道：如果这位 Humpty Dumpty 是奥本海默，则一旦摔碎后便如歌中所唱那样难以复原，烁烁其华不再，因为奥本海默是复杂和多态的。然而如果 Humpty Dumpty 是拉比的话，即便摔得粉碎也会复原如初，因为拉比的存在状态只有一个。 的确，奧本海默象是一个不稳定的多态粒子，环境因素经常可以导致态的越迁；而拉比的生命本征向量却是唯一的，世态时局，战争政事，都不过是微扰项，不会改变其既定的方向。 睿智且坚定，这正是拉比留给我的印象。
去年在Imperial College伦敦帝国理工学院参加MICCAI'09会议期间，有幸听了核磁共振扫描仪发明者, Sir P. Mansfield的主题讲座An audience with pioneers。Mansfield与Lauterbur同获2003 年的医学与生理学诺贝尔奖。 讲座由杨广中教授主持, 参与者亦有 Hounsfield 的朋友Longmore教授。杨教授穿针引线，要Manfield介绍核磁共振扫描仪的种种曲折，故事。Mansfield大致介绍了他当时的构想，实验及原始设计。杨问，您当时有没有想过得奖？ Mansfield答，根本没想这些，就是凭着兴趣，一股子干劲， to get things done. 讲座现场（中为Manfield）：
德国Maier M等于2010年4月在《Unfallchirurg.》医学杂志上撰文，总结了儿童与青少年膝关节急性损伤诊断路径的昨天和今天。 文中称：对于儿童和青少年的急性膝关节损伤，临床体格检查通常是很困难的。因此核磁共振常用于作为一个辅助诊断工具。本文主要是一方面评价关节镜检查的适应症，一方面评价膝关节核磁共振检查的适应症。方法：1990年至1999年，87名（第一组）患者在进行临床体格检查后进行了关节镜检查。在2000年到2006年，83名（第二组）患者在临床体格检查后使用了核磁共振检查，53例随后还进行了关节镜检查。结果：第一组患者，79%的临床诊断得到了关节镜检查的验证。在第二组，临床检查和关节镜检查的诊断的一致率是60%。由于运用膝关节核磁共振检查，诊断性膝关节镜的使用率可从22%下降到13%。结论：儿童与青少年的诊断性关节镜手术可以通过使用膝关节核磁共振获得减少。 Pubmed相关链接： http://www.ncbi.nlm.nih.gov/pubmed/20414633 Unfallchirurg. 2010 Apr 23. Maier M, Geiger EV, Sellnow L, Schneidmller D, Vennemann N, Mack M, Marzi I. Klinik fr Unfall-, Hand- und Wiederherstellungschirurgie, Klinikum der Johann Wolfgang Goethe-Universitt, Frankfurt am Main, Theodor-Stern-Kai 7, 60596, Frankfurt am Main, Deutschland 启示：对于儿童和青少年膝关节急性损伤而言，单纯的临床体格检查往往不能够准确判断出膝关节内部损伤的程度。膝关节核磁共振检查和膝关节关节镜诊断性手术检查可以帮助确诊。膝关节核磁共振检查有助于减少膝关节关节镜诊断性手术的使用率。 （江苏省徐州医学院附属医院骨科 膝关节方向 高绪仁 编译）
美国Rosas HG在2009年6月的《Top Magn Reson Imaging》（核磁共振专题）杂志上撰文，总结了膝关节半月板的核磁共振MRI影像学。 文中称：在诊断膝关节半月板损伤上，膝关节核磁共振影像学技术已经发展成为一项具有高精确性的方法。膝关节核磁共振片子上可以显示出必要的解剖学细节。在这个保留半月板为导向的年代，膝关节核磁共振可以帮助我们选择相应的治疗策略。若想很准确的解读膝关节核磁共振片子，需要对半月板解剖学、半月板功能、半月板解剖变异、核磁共振技术、膝关节半月板撕裂的核磁共振表现、伴发的膝关节韧带损伤、膝关节半月板误诊的原因以及联合临床体格检查的重要性有全面的理解和把握。 Pubmed相应链接： http://www.ncbi.nlm.nih.gov/pubmed/20410803 Top Magn Reson Imaging. 2009 Jun;20(3):151-73. Magnetic resonance imaging of the meniscus. Rosas HG, De Smet AA. Department of Radiology, University of Wisconsin, Madison, WI 53792, USA. 启示：随着我国人民生活水平的提高，体育运动的增加，膝关节半月板损伤的患者也越来越多。膝关节核磁共振检查是一项很好的无创检查膝关节半月板损伤情况的手段和方法。但是，为了能够更好地解释膝关节核磁共振片子的病理意义，我们需要进一步提高对半月板解剖学、半月板功能、半月板解剖变异、核磁共振技术、膝关节半月板撕裂的核磁共振表现、伴发的膝关节韧带损伤、膝关节半月板误诊的原因以及联合临床体格检查的重要性的理解和把握。 （江苏省徐州医学院附属医院骨科 膝关节方向 高绪仁 编译）
标签: 核磁共振
