26 research outputs found
Monosized dripping mode of axisymmetric flow focusing
We identify and analyze the perfectly regular dripping mode of flow focusing. This mode occurs within narrow
intervals of injected flow rates and applied pressure drops and leads to homogeneous-size droplets with diameters
similar to or smaller than that of the discharge orifice. The balance between the local acceleration of the fluid
particle and the applied pressure drop yields the scaling law for the droplet diameter. This scaling law is validated
experimentally with excellent accord.Ministerio de Economía, Industria y Competitividad DPI2013-46485Gobierno de Extremadura GR1004
Megahertz serial crystallography
The new European X-ray Free-Electron Laser is the first X-ray free-electron laser capable of delivering X-ray pulses with a megahertz inter-pulse spacing, more than four orders of magnitude higher than previously possible. However, to date, it has been unclear whether it would indeed be possible to measure high-quality diffraction data at megahertz pulse repetition rates. Here, we show that high-quality structures can indeed be obtained using currently available operating conditions at the European XFEL. We present two complete data sets, one from the well-known model system lysozyme and the other from a so far unknown complex of a β-lactamase from K. pneumoniae involved in antibiotic resistance. This result opens up megahertz serial femtosecond crystallography (SFX) as a tool for reliable structure determination, substrate screening and the efficient measurement of the evolution and dynamics of molecular structures using megahertz repetition rate pulses available at this new class of X-ray laser source
Rapid sample delivery for megahertz serial crystallography at X-ray FELs
Liquid microjets are a common means of delivering protein crystals to the focus
of X-ray free-electron lasers (FELs) for serial femtosecond crystallography
measurements. The high X-ray intensity in the focus initiates an explosion of the
microjet and sample. With the advent of X-ray FELs with megahertz rates, the
typical velocities of these jets must be increased significantly in order to
replenish the damaged material in time for the subsequent measurement with
the next X-ray pulse. This work reports the results of a megahertz serial
diffraction experiment at the FLASH FEL facility using 4.3 nm radiation. The
operation of gas-dynamic nozzles that produce liquid microjets with velocities
greater than 80 m s1 was demonstrated. Furthermore, this article provides
optical images of X-ray-induced explosions together with Bragg diffraction from
protein microcrystals exposed to trains of X-ray pulses repeating at rates of up
to 4.5 MHz. The results indicate the feasibility for megahertz serial crystallography measurements with hard X-rays and give guidance for the design of
such experiments.Unión Europea 7PM / 2007-2013Consejo de Investigación de Australia DP170100131Ministerio de Economía, Industria y Competitividad DPI2016-78887-C3-1-RNational Science Foundation "BioXFEL" (1231306
Rapid sample delivery for megahertz serial crystallography at X-ray FELs
Liquid microjets are a common means of delivering protein crystals to the focus of X-ray free-electron lasers (FELs) for serial femtosecond crystallography measurements. The high X-ray intensity in the focus initiates an explosion of the microjet and sample. With the advent of X-ray FELs with megahertz rates, the typical velocities of these jets must be increased significantly in order to replenish the damaged material in time for the subsequent measurement with the next X-ray pulse. This work reports the results of a megahertz serial diffraction experiment at the FLASH FEL facility using 4.3 nm radiation. The operation of gas-dynamic nozzles that produce liquid microjets with velocities greater than 80 m s-1 was demonstrated. Furthermore, this article provides optical images of X-ray-induced explosions together with Bragg diffraction from protein microcrystals exposed to trains of X-ray pulses repeating at rates of up to 4.5 MHz. The results indicate the feasibility for megahertz serial crystallography measurements with hard X-rays and give guidance for the design of such experiments
Micro/nano liquid ejection via electrohydrodynamic fields and gaseous streams. Application in structural biology with xfel
Premio Extraordinario de Doctorado U
Aerodynamically stabilized Taylor cone jets
We introduce a way to produce steady micro/nano-liquid jets via electrohydrodynamic elds
together with co-
owing gas streams. We study the dripping-jetting transition of this con guration
theoretically through a global stability analysis as a function of the governing parameters involved.
A balance between the local radial acceleration to the surface tension gradient, the mass conservation
and the energy balance equations enable us to derive two coupled scaling laws that predict both
the minimum jet diameter and its maximum velocity. The theoretical prediction provides a single
curve that describes not only the numerical computations but also experimental data from the
literature for cone-jets. Additionally, we performed a set of experiments to verify what parameters
in
uence the jet length. We adopt a very recent model for capillary jet length to our con guration by
combining electrohydrodynamic e ects with the gas
ow through an equivalent liquid pressure. Due
to the diameters below 1 micrometer and high speeds attainable in excess of 100 m/s, this concept
has the potential to be utilized for structural biology analyses with X-ray free-electron lasers at
megahertz repetition rates as well as other applications.Ministerio de Economia y Competitividad DPI2016-78887-C3-1-
Megahertz pulse trains enable multi-hit serial femtosecond crystallography experiments at X-ray free electron lasers
This article is licensed under a Creative Commons
Attribution 4.0 International License, which permits use, sharing,
adaptation, distribution and reproduction in any medium or format, as
long as you give appropriate credit to the original author(s) and the
source, provide a link to the Creative Commons license, and indicate if
changes were made. The images or other third party material in this
article are included in the article’s Creative Commons license, unless
indicated otherwise in a credit line to the material. If material is not
included in the article’s Creative Commons license and your intended
use is not permitted by statutory regulation or exceeds the permitted
use, you will need to obtain permission directly from the copyright
holder. To view a copy of this license, visit http://creativecommons.org/
licenses/by/4.0/.The European X-ray Free Electron Laser (XFEL) and Linac Coherent Light
Source (LCLS) II are extremely intense sources of X-rays capable of generating
Serial Femtosecond Crystallography (SFX) data at megahertz (MHz) repetition
rates. Previous work has shown that it is possible to use consecutive X-ray
pulses to collect diffraction patterns from individual crystals. Here, we exploit
the MHz pulse structure ofthe European XFEL to obtain two complete datasets
from the same lysozyme crystal, first hit and the second hit, before it exits the
beam. The two datasets, separated by <1 µs, yield up to 2.1 Å resolution
structures. Comparisons between the two structures reveal no indications of
radiation damage or significant changes within the active site, consistent with
the calculated dose estimates. This demonstrates MHz SFX can be used as a
tool for tracking sub-microsecond structural changes in individual single
crystals, a technique we refer to as multi-hit SFX
The Natural Breakup Length of a Steady Capillary Jet: Application to Serial Femtosecond Crystallography
One of the most successful ways to introduce samples in Serial Femtosecond Crystallography has been the use of microscopic capillary liquid jets produced by gas flow focusing, whose length-to-diameter ratio and velocity are essential to fulfill the requirements of the high pulse rates of current XFELs. In this work, we demonstrate the validity of a classical scaling law with two universal constants to calculate that length as a function of the liquid properties and operating conditions. These constants are determined by fitting the scaling law to a large set of experimental and numerical measurements, including previously published data. Both the experimental and numerical jet lengths conform remarkably well to the proposed scaling law. We show that, while a capillary jet is a globally unstable system to linear perturbations above a critical length, its actual and shorter long-term average intact length is determined by the nonlinear perturbations coming from the jet breakup itself. Therefore, this length is determined solely by the properties of the liquid, the average velocity of the liquid and the flow rate expelled. This confirms the very early observations from Smith and Moss 1917, Proc R Soc Lond A Math Phys Eng, 93, 373, to McCarthy and Molloy 1974, Chem Eng J, 7, 1, among others, while it contrasts with the classical conception of temporal stability that attributes the natural breakup length to the jet birth conditions in the ejector or small interactions with the environment
The natural breakup length of a steady capillary jet
72 American Physical Society Division of Fluid Dynamics 2019Despite their fundamental and applied importance, a general model to predict the natural breakup
length of steady capillary jets has not been proposed yet. In this work, we derive a scaling law with
two universal constants to calculate that length as a function of the liquid properties and operating
conditions. These constants are determined by fitting the scaling law to a large set of experimental
and numerical measurements, including previously published data. Both the experimental and
numerical jet lengths conform remarkably well to the proposed scaling law. This law is explained in
terms of the growth of perturbations excited by the jet breakup itself