Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

Time and frequency -Domain Interpretation of Phase-lead Control01:24

Time and frequency -Domain Interpretation of Phase-lead Control

102
Phase-lead controllers are commonly used in various control systems to enhance response speed and stability. Adjusting the brightness on a television screen offers a practical example of phase-lead control. When contrast is enhanced, a phase-lead controller is employed. Mathematically, phase-lead control is identified when the first parameter is smaller than the second.
The design of phase-lead control involves the strategic placement of poles and zeros to balance steady-state error and system...
102
Phase Changes01:19

Phase Changes

4.4K
Phase transitions play an important theoretical and practical role in the study of heat flow. In melting or fusion, a solid turns into a liquid; the opposite process is freezing. In evaporation, a liquid turns into a gas; the opposite process is condensation.
A substance melts or freezes at a temperature called its melting point and boils or condenses at its boiling point. These temperatures depend on pressure. High pressure favors the denser form of the substance, so typically, high pressure...
4.4K
Propagation of Uncertainty from Random Error00:59

Propagation of Uncertainty from Random Error

725
An experiment often consists of more than a single step. In this case, measurements at each step give rise to uncertainty. Because the measurements occur in successive steps, the uncertainty in one step necessarily contributes to that in the subsequent step. As we perform statistical analysis on these types of experiments, we must learn to account for the propagation of uncertainty from one step to the next. The propagation of uncertainty depends on the type of arithmetic operation performed on...
725
Problem Solving: Dimensional Analysis01:08

Problem Solving: Dimensional Analysis

3.5K
Every mathematical equation that connects separate distinct physical quantities must be dimensionally consistent, which implies it must abide by two rules. For this reason, the concept of dimension is crucial. The first rule is that an equation's expressions on either side of an equality must have the exact same dimension, i.e., quantities of the same dimension can be added or removed. The second rule stipulates that all popular mathematical functions, such as exponential, logarithmic, and...
3.5K
Time and frequency -Domain Interpretation of Phase-lag Control01:21

Time and frequency -Domain Interpretation of Phase-lag Control

115
Phase-lag controllers are widely used in control systems to improve stability and reduce steady-state errors. A dimmer switch controlling the brightness of a light bulb serves as a practical example of phase-lag control, gradually adjusting the bulb's brightness. Mathematically, phase-lag control or low-pass filtering is represented when the factor 'a' is less than 1.
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any...
115
Chronopharmacokinetics: Time-Dependent Pharmacokinetics01:20

Chronopharmacokinetics: Time-Dependent Pharmacokinetics

163
Chronopharmacokinetics studies the temporal change in drug absorption and elimination. These changes can be cyclical or non-cyclical. Cyclical changes occur over a regular interval, while non-cyclical changes occur over a longer, irregular period.
Time-dependent pharmacokinetics refers to non-cyclical changes in drug rate processes over a period of time. It can lead to nonlinear pharmacokinetics, where the relationship between drug concentration and time is not proportional. Non-cyclical...
163

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

Conformational equilibria in the activation of cystine-knot hormone receptors.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Small molecule inhibitor of PPARγ acetylation promotes insulin sensitization and browning of white adipose tissue with improved safety.

bioRxiv : the preprint server for biology·2025
Same author

The asymmetric opening of HIV-1 Env by a potent CD4 mimetic enables anti-coreceptor binding site antibodies to mediate ADCC.

Nature communications·2025
Same author

Structure of an LGR dimer, an evolutionary predecessor of glycoprotein hormone receptors.

Nature communications·2025
Same author

Cholesterol-dependent enzyme activity of human TSPO1.

Proceedings of the National Academy of Sciences of the United States of America·2025
Same author

Structural and evolutionary insights into the functioning of glycoprotein hormones and their receptors.

Andrology·2025
Same journal

Towards light-coupled sample preparation for time-resolved cryoEM studies.

IUCrJ·2026
Same journal

Cryo-EM analysis of cooperative conformational changes in the SARS-CoV-2 spike protein trimer.

IUCrJ·2026
Same journal

Towards time-resolved MicroED grid preparation using mix-and-inject gas dynamic virtual nozzles.

IUCrJ·2026
Same journal

How cryoEM has advanced our understanding of bacteriophages and bacteriocins targeting Clostridioides difficile.

IUCrJ·2026
Same journal

CryoEM structures reveal allosteric regulation of the catalytic activity of the multi-protein human MAT enzyme complexes.

IUCrJ·2026
Same journal

Cryo-EM-guided subtractive optimization of a novel VCP/p97 inhibitor.

IUCrJ·2026
查看所有相关文章

相关实验视频

Updated: Jul 17, 2025

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
10:03

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

18.0K

面对相位问题的解决方法

Wayne A Hendrickson1

  • 1Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.

IUCrJ
|September 5, 2023
PubMed
概括
此摘要是机器生成的。

在X射线晶体学中,相位问题已经通过不断发展的方法,如异常衍射和分子替换来克服. 人工智能和冷电子显微镜 (cryo-EM) 的进步现在为确定原子结构提供了强大的替代方案.

关键词:
异常衍射异常的衍射情况密度的修改 密度的修改直接方法 直接方法同型的替代物是同型的替代物.分子替代的分子替代.

更多相关视频

Measuring the Time-Evolution of Nanoscale Materials with Stopped-Flow and Small-Angle Neutron Scattering
07:53

Measuring the Time-Evolution of Nanoscale Materials with Stopped-Flow and Small-Angle Neutron Scattering

Published on: August 6, 2021

2.2K
Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
10:39

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating

Published on: October 11, 2016

9.7K

相关实验视频

Last Updated: Jul 17, 2025

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
10:03

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

18.0K
Measuring the Time-Evolution of Nanoscale Materials with Stopped-Flow and Small-Angle Neutron Scattering
07:53

Measuring the Time-Evolution of Nanoscale Materials with Stopped-Flow and Small-Angle Neutron Scattering

Published on: August 6, 2021

2.2K
Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
10:39

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating

Published on: October 11, 2016

9.7K

科学领域:

  • 结构生物学 结构生物学
  • 生物物理学的生物物理.
  • 晶体学 晶体学是指结晶学.

背景情况:

  • 射线晶体学从衍射模式确定原子结构,但需要评估波段.
  • 阶段问题是结构确定的一个核心挑战,它影响了理论理解和实际分析.
  • 从历史上看,宏分子晶体学依赖于同态替换,后来转向异常衍射来进行新的结构确定.

研究的目的:

  • 审查在X射线晶体学中解决相位问题的方法的历史演变.
  • 讨论结构生物学界如何解决和克服相位问题.
  • 突出原子结构确定中的当前趋势和替代技术.

主要方法:

  • 实验分相技术的演变,包括同型替换,多波长异常衍射 (MAD) 和单波长异常衍射 (SAD).
  • 分子替代的开发和应用,特别是随着蛋白质结构数据库的增长.
  • 直接方法的集成用于特定的亚结构分析和本地SAD的兴起.
  • 利用人工智能 (AI) 模型,如AlphaFold,用于结构预测和分阶段.

主要成果:

  • 异常衍射成为主导 de novo 确定,MAD 和 SAD 是关键的实验分相方法.
  • 在蛋白质家族关系和数据库的帮助下,分子替代成为已知的结构的主要方法.
  • 直接方法在分析SAD内部的基结构方面发现有用.
  • 原生SAD利用内在原子 (S,P) 现在是常规的,像AlphaFold这样的AI模型越来越多地避免实验阶段化.

结论:

  • 结构生物学界已经成功地开发和完善了方法来克服X射线晶体学中的相位问题.
  • 目前的技术,包括人工智能驱动的预测和冷EM,为传统晶体学提供了强大的替代方案和补充方法.
  • 虽然晶体学原理仍然很重要,但冷电磁场在许多结构生物学应用中通过绕过相位问题提供了直接的解决方案.