Rezaev R.O.,National Research Nuclear University |
Levchenko E.A.,Tomsk Polytechnic University |
Schmidt O.G.,Institute for Integrative Nanosciences |
Schmidt O.G.,TU Chemnitz |
Fomin V.M.,Institute for Integrative Nanosciences
Russian Physics Journal | Year: 2015
We consider the special features at nano- and microscales of the vortex dynamics on superconducting cylindrical Nb tubes produced by the roll-up (self-rolling) technique. A transport current enters the tube through electrodes placed on both sides of a cut (in the paraxial direction) of the tube. The system is in the magnetic field perpendicular to the tube axis. The vortex dynamics is described by means of characteristic times: time (Δt1) needed for a vortex to move from one edge of the tube to another and time (Δt2) between two consecutive vortex nucleation events at one edge of the tube. A range of magnetic field values is analyzed where Δt1 as a function of the magnetic field has a highly nonlinear and non-monotonic behavior. For certain values of the magnetic field, two different trajectories are possible for a moving vortex, i.e., a bifurcation phenomenon occurs. We explain the reason of this bifurcation. © 2015, Springer Science+Business Media New York.
News Article | January 14, 2016
A National Survey of Family Growth found that 7.5 percent of sexually experienced men under the age of 45 have seen a fertility doctor. That percentage correlates to between 3.3 and 4.7 million men. Of those men, around 17 percent were found to be infertile. There are a myriad of factors that can contribute to male infertility, from medical conditions to environmental toxins. And one of the outcomes is low sperm motility. Researchers from the Institute for Integrative Nanosciences at IFW Dresden believe they’ve come up with a method to help improve a slow-swimming sperm’s chance of fertilizing an egg. And it involves micromotors. In a video published by the American Chemical Society, the researchers show how tiny metal helices—just large enough to fit around the tail of a sperm—can bolster their swimming. The helices movements are controlled via a rotating magnetic field, which helps drive the sperm into an egg. While the work is still in its nascent stages, the researchers believe the success of the initial experiment is promising for the future. The researchers believe the burgeoning technique may be an alternative to artificial insemination, or in vitro fertilization. According to the U.K.’s Human Fertilisation and Embryology Authority, artificial insemination has an average success rate under 30 percent. In vitro fertilization—which involves removing the egg from a woman’s ovaries, fertilizing it outside the body, then placing it in either the woman’s or a surrogate’s uterus—varies in success depending on the age of the woman. According to the Centers for Disease Control and Prevention, 40 percent of woman under age 35 successfully saw a live birth after in vitro fertilization. The percentage declines as the age increases. The researchers published their findings in Nano Letters.
News Article | January 20, 2016
Sperm that don’t swim well rank high among the main causes of infertility. To give these cells a boost, women trying to conceive can turn to artificial insemination or other assisted reproduction techniques, but success can be elusive. In an attempt to improve these odds, scientists have developed motorized “spermbots” that can deliver poor swimmers — that are otherwise healthy — to an egg. Their report appears in ACS’ journal Nano Letters. Artificial insemination is a relatively inexpensive and simple technique that involves introducing sperm to a woman’s uterus with a medical instrument. Overall, the success rate is on average under 30 percent, according to the Human Fertilisation & Embryology Authority of the United Kingdom. In vitro fertilization can be more effective, but it’s a complicated and expensive process. It requires removing eggs from a woman’s ovaries with a needle, fertilizing them outside the body and then transferring the embryos to her uterus or a surrogate’s a few days later. Each step comes with a risk for failure. Mariana Medina-Sánchez, Lukas Schwarz, Oliver G. Schmidt, and colleagues from the Institute for Integrative Nanosciences at IFW Dresden in Germany wanted to see if they could come up with a better option than the existing methods. Building on previous work on micromotors, the researchers constructed tiny metal helices just large enough to fit around the tail of a sperm. Their movements can be controlled by a rotating magnetic field. Lab testing showed that the motors can be directed to slip around a sperm cell, drive it to an egg for potential fertilization, and then release it. The researchers say that although much more work needs to be done before their technique can reach clinical testing, the success of their initial demonstration is a promising start.
News Article | January 15, 2016
Home > Press > 'Spermbots' could help women trying to conceive (video) Abstract: Sperm that don't swim well rank high among the main causes of infertility. To give these cells a boost, women trying to conceive can turn to artificial insemination or other assisted reproduction techniques, but success can be elusive. In an attempt to improve these odds, scientists have developed motorized "spermbots" that can deliver poor swimmers -- that are otherwise healthy -- to an egg. Their report appears in ACS' journal Nano Letters. Artificial insemination is a relatively inexpensive and simple technique that involves introducing sperm to a woman's uterus with a medical instrument. Overall, the success rate is on average under 30 percent, according to the Human Fertilisation & Embryology Authority of the United Kingdom. In vitro fertilization can be more effective, but it's a complicated and expensive process. It requires removing eggs from a woman's ovaries with a needle, fertilizing them outside the body and then transferring the embryos to her uterus or a surrogate's a few days later. Each step comes with a risk for failure. Mariana Medina-Sánchez, Lukas Schwarz, Oliver G. Schmidt and colleagues from the Institute for Integrative Nanosciences at IFW Dresden in Germany wanted to see if they could come up with a better option than the existing methods. Building on previous work on micromotors, the researchers constructed tiny metal helices just large enough to fit around the tail of a sperm. Their movements can be controlled by a rotating magnetic field. Lab testing showed that the motors can be directed to slip around a sperm cell, drive it to an egg for potential fertilization and then release it. The researchers say that although much more work needs to be done before their technique can reach clinical testing, the success of their initial demonstration is a promising start. About American Chemical Society The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 158,000 members, ACS is the world's largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio. For more information, please click Contacts: Michael Bernstein 202-872-6042 Mariana Medina-Sánchez, Ph.D. Institute for Integrative Nanosciences IFW Dresden Dresden, Germany or Lukas Schwarz, M.Sc. Institute for Integrative Nanosciences IFW Dresden Dresden, Germany or Oliver G. Schmidt, Ph.D. Institute for Integrative Nanosciences IFW Dresden Dresden, Germany http://www.ifw-dresden.de/de/institute/iin If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Ulhaq A.,University of Sheffield |
Duan Q.,University of Sheffield |
Zallo E.,Institute for Integrative Nanosciences |
Zallo E.,Paul Drude Institute for Solid State Electronics |
And 5 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2016
GaAs/AlGaAs quantum dots grown by in situ droplet etching and nanohole in-filling offer a combination of strong charge confinement, optical efficiency, and high spatial symmetry advantageous for polarization entanglement and spin-photon interface. Here, we study experimentally electron and nuclear spin properties of such dots. We find nearly vanishing electron g factors (ge<0.05), providing a potential route for electrically driven spin control schemes. Optical manipulation of the nuclear spin environment is demonstrated with nuclear spin polarization up to 65% achieved. Nuclear magnetic resonance spectroscopy reveals two distinct types of quantum dots: with tensile and with compressive strain along the growth axis. In both types of dots, the magnitude of strain ϵb<0.02% is nearly three orders of magnitude smaller than in self-assembled dots: On the one hand, this provides a route for eliminating a major source of electron spin decoherence arising from nuclear quadrupolar interactions, and on the other hand such strain is sufficient to suppress nuclear spin diffusion leading to a stable nuclear spin bath with nuclear spin lifetimes exceeding 500 s. The spin properties revealed in this work make this new type of quantum dot an attractive alternative to self-assembled dots for the applications in quantum information technologies. © 2016 American Physical Society.
Tetz M.,Berlin Eye Research Institute |
Jorgensen M.R.,Institute for Integrative Nanosciences
Current Eye Research | Year: 2015
An introduction to the history of intraocular lenses (IOLs) is given, leading up to modern hydrophobic examples. The roles of hydrophobicity, hygroscopy, materials chemistry, and edge design are discussed in the context of IOLs. The four major types of IOL materials are compared in terms of their chemistry and biocompatibility. An example of a modern "hydrophobic" acrylic polymer with higher water content is discussed in detail. © 2015 © 2015 Taylor & Francis Group, LLC.
Wolf M.,Leibniz Institute for Solid State and Materials Research |
Patschureck C.,Leibniz Institute for Solid State and Materials Research |
Schfer R.,Leibniz Institute for Solid State and Materials Research |
Mnch I.,Institute for Integrative Nanosciences |
And 3 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2011
The dynamic magnetic properties of soft-ferromagnetic thin film element arrays are strongly influenced by long range interelement magnetostatic interaction. In order to estimate the effective array dipolar field a quantitative model is presented, which is based on the superposition of stray fields that arise from the neighborhood of a reference element. Kittel's equation, that describes the magnetodynamics, is generalized for magnetically saturated arrays by additional array dipolar field terms. Measurements of the magnetodynamic response of quasi-saturated arrays with a rectangular base agree with theoretical predictions. Thus, our model allows the estimation of the frequency of the uniform precessional mode in mesoscopic thin film arrays with non-negligible magnetostatic interaction. © 2011 Elsevier B.V.
Li G.,Technical University Chemnitz09107 ChemnitzGermany |
Grimm D.,Technical University Chemnitz09107 ChemnitzGermany |
Engemaier V.,Institute for Integrative Nanosciences |
Losch S.,Technical University Chemnitz09107 ChemnitzGermany |
And 4 more authors.
Physica Status Solidi (A) Applications and Materials Science | Year: 2016
Multilayer systems consisting of periodic hybrid interfaces show promising applications in thermoelectric design in terms of unique phonon blocking and electron conducting features. Universal techniques combining crystalline semiconductors with various categories of metals, oxides, molecules, and polymers have been rarely reported. In this paper, we first briefly review a novel rolled-up and compressing technique based on a strain engineered In0.2Ga0.8As/GaAs semiconducting nanomembrane. Then, the controllable rolling and compressing of a nanomembrane, focused ion beam cutting and the following device fabrication steps are demonstrated for the system of a hybrid In0.2Ga0.8As/GaAs/Cr/Au superlattice. Apart from a considerable reduction of thermal conductivity in a similar system reported by part of us very recently, here our efforts are focused on characterizing the cross-plane electrical conductance of the hybrid superlattice. High electrical conductance of four separated devices show very tight electrical bonding across the hybrid interfaces. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Ernst D.,TU Dresden |
Monch J.I.,TU Dresden |
Schmidt O.G.,Institute for Integrative Nanosciences |
Zerna T.,TU Dresden
20th European Microelectronics and Packaging Conference and Exhibition: Enabling Technologies for a Better Life and Future, EMPC 2015 | Year: 2015
Several applications require (ultra-)thin and reliable packaging of the sensor electronics. Especially the rapidly increasing use of sensor elements in nearly every field of engineering is the main driver for that fact. One specific application is magnetic field sensors in active magnetic bearings. In order to improve their precision and stiffness those bearings can be beneficially operated by measuring the magnetic flux inside the air gap in between the curved stator and rotor components. To achieve proper and reliable sensor integration, both the sensor elements and the packaging have to meet the requirements concerning total height and bendability. Therefore the maximum sensor thickness must not exceed 200 μm. For the reliable mounting of the sensor onto the stator pole it is also necessary, that those sensors have to be bendable down to radii of 25 mm. As a consequence the sensor package needs to be flexible as well. © 2015 IMAPS Europe.
News Article | January 17, 2016
Each year, millions of Americans will struggle to conceive a child. The causes of infertility issues are manifold, but one of the major sources of infertility in men is due to something called low sperm motility, meaning the sperm struggles to swim toward the egg. There are, of course, procedures for those with fertility issues, although the two most common options—in vitro fertilization and artificial insemination—have relatively low levels of success. So in an effort to provide a more effective solution to infertility, particularly infertility resulting from low sperm motility, a team of researchers at German Institute for Integrative Nanosciences has harnessed the awesome power of magnetic fields to create a tiny robotic tail for struggling sperm. In a study recently published in Nano Letters, the team unveiled its spermbot, which is essentially a small metal coil (called a ferromagnetic microtube) large enough to fit around the tail of a sperm, but not large enough to slip over the head. The research team used a rotating magnetic field to guide the microtube to a sperm, making use of the sperm’s tail to propel the microtube encased sperm toward an egg. When the sperm reaches the egg, it begins the fertilization process and as it enters the egg, its robotic tail simply slips off. While this is a pretty awesome solution to infertility, the idea for the spermbot has been around for a few years. The team was building on initial successes experienced in 2013 by another team from the institute, making small but important alterations to the motor’s design, most notably the change from a more classic tube to the helix shape seen above. According to the team, this infertility treatment has several advantages not found in currently existing alternatives. It is relatively uncomplicated, especially when compared with in vitro fertilization which involves extracting an egg, inseminating it outside the body and then reinjecting it into the uterus. Moreover, the spermbot could be deployed at a fraction of the cost of alternative treatments, which can cost upwards of $10,000 per cycle for in vitro fertilizations and over $1000 for artificial inseminations. That being said, the spermbot was only tested out in a laboratory setting using bovine sperm, which share many characteristics with human sperm. Deploying it in humans would involve a whole host of challenges not found in a petri dish, such as the complications of using a magnetic field to guide the sperm without being able to see the motor’s movements while in the body. Moreover, while the magnetic fields used in the spermbot do not harm the body’s living tissue and the robotic tales do minimal damage to the sperm themselves, the research team still needs to see how a woman’s immune system would react to the presence of these foreign bodies. “Unfortunately, similar to many promising applications in biomedical engineering, it appears to be still a long way from artificially motorized sperm delivery to actual…fertilization,” the team wrote in its study. “Still, this work serves to demonstrate a new approach to artificial reproduction that is, in principle, also applicable in vivo and would thus allow to avoid all complications that arise from [in vitro fertilization].”