Press releases archive
Dec
23
2020
13:55
Collaboration between 51猎奇 and the University of Oklahoma
Quantum wave in helium dimer filmed for the first time
For the first time, an international team of
scientists from 51猎奇 and the University of Oklahoma has succeeded
in filming quantum physical effects on a helium dimer as it breaks apart. The
film shows the superposition of matter waves from two simultaneous events that
occur with different probability: The survival and the disintegration of the
helium dimer. This method might in future make it possible to track
experimentally the formation and decay of quantum Efimov systems (Nature
Physics, DOI 10.1038/s41567-020-01081-3).
FRANKFURT. Anyone
entering the world of quantum physics must prepare themself for quite a few
things unknown in the everyday world: Noble gases form compounds, atoms behave
like particles and waves at the same time and events that in the macroscopic
world exclude each other occur simultaneously.
In the world of quantum physics, Reinhard
D枚rner and his team are working with molecules which 鈥� in the sense of most
textbooks 鈥� ought not to exist: Helium compounds with two atoms, known as helium
dimers. Helium is called a noble gase precisely because it does not form any
compounds. However, if the gas is cooled down to just 10 degrees above absolute
zero (minus 273 掳C) and then pumped through a small nozzle into a vacuum
chamber, which makes it even colder, then 鈥� very rarely 鈥� such helium dimers
form. These are unrivaledly the weakest bound stable molecules in the Universe,
and the two atoms in the molecule are correspondingly extremely far apart from
each other. While a chemical compound of two atoms commonly measures about 1
angstrom (0.1 nanometres), helium dimers on average measure 50 times as much,
i.e. 52 angstrom.
The scientists in Frankfurt irradiated
such helium dimers with an extremely powerful laser flash, which slightly
twisted the bond between the two helium atoms. This was enough to make the two
atoms fly apart. They then saw 鈥� for the very first time 鈥� the helium atom
flying away as a wave and record it on film.
According to quantum physics, objects
behave like a particle and a wave at the same time, something that is best
known from light particles (photons), which on the one hand superimpose like
waves where they can pile upor extinguish each other (interference), but on the
other hand as 鈥渟olar wind鈥� can propel spacecraft via their solar sails, for
example.
That the researchers were able to observe
and film the helium atom flying away as a wave at all in their laser experiment
was due to the fact that the helium atom only flew away with a certain
probability: With 98 per cent probability it was still bound to its second
helium partner, with 2 per cent probability it flew away. These two helium atom waves 鈥� Here it comes! Quantum
physics! 鈥� superimpose and their interference could be measured.
The measurement of such 鈥渜uantum waves鈥�
can be extended to quantum systems with several partners, such as the helium
trimer composed of three helium atoms. The helium trimer is interesting because
it can form what is referred to as an 鈥渆xotic Efimov state鈥�, says Maksim
Kunitski, first author of the study: 鈥淪uch three-particle systems were
predicted by Russian theorist Vitaly Efimov in 1970 and first corroborated on
caesium atoms. Five years ago, we discovered the Efimov state in the helium
trimer. The laser pulse irradiation method we鈥檝e now developed might allow us
in future to observe the formation and decay of Efimov systems and thus better
understand quantum physical systems that are difficult to access
experimentally.鈥�
Publication:
Maksim Kunitski, Qingze Guan, Holger
Maschkiwitz, J枚rg Hahnenbruch, Sebastian Eckart, Stefan Zeller, Anton Kalinin,
Markus Sch枚ffler, Lothar Ph. H. Schmidt, Till Jahnke, D枚rte Blume, Reinhard
D枚rner: Ultrafast manipulation of the
weakly bound helium dimer. In: Nature Physics,
Pictures
to download:
Caption: Dr Maksim Kunitski next to the COLTRIMS reaction microscope at 51猎奇, which was used to observe the 鈥渜uantum wave鈥�. (Photo: Uwe Dettmar for 51猎奇)
Caption: Professor Reinhard D枚rner (left) and Dr Maksim Kunitzki in front of the COLTRIMS reaction microscope at 51猎奇, which was used to observe the quantum wave. (Photo: 51猎奇 Frankfurt)
Video:
Professor Reinhard D枚rner
Institute for Nuclear Physics
Tel.: +49 (0)69 798-47003
doerner@atom.uni-frankfurt.de
Statement by the authors
Researchers
at 51猎奇 Frankfurt had recently reported in an article and a press
release on the influence of the active substance loperamide on cell death in
brain tumour cells. As a result, the German Brain Tumour Centres have received numerous
enquiries about the therapeutic use of loperamide in patients with brain tumour
diseases.
It should
be noted, however, that the underlying research is based solely on cell culture
models. Under no circumstances can recommendations for the treatment of humans
be derived from the results. In addition to intestinal sluggishness, loperamide
can cause severe and life-threatening side effects, especially when used in
higher doses or not as intended.
The authors
of the research article and the focus of neuro-oncology at the University Cancer
Center (UCT) therefore strongly advise against the use of loperamide in brain
tumour patients (beyond the indication of diarrhoea).
Professor
Christian Brandts
Director University Cancer Center Frankfurt (UCT),
University Hospital Frankfurt
Professor
Joachim Steinbach
Director of the Dr. Senckenbergischen Institute for Neuro-Oncology, UCT, University Hospital Frankfurt
Sjoerd J. L. van Wijk, Ph.D.
Institute of Experimental Cancer Research in
Paediatrics , UCT, University Hospital Frankfurt
In
cell culture, loperamide, a drug commonly used against diarrhoea, proves
effective against glioblastoma cells. A research team at 51猎奇 has
now unravelled the drug's mechanisms of
action of cell death induction and 鈥� in doing so 鈥� has shown how this compound
could help attack brain tumours that otherwise are difficult to treat.
FRANKFURT. The
research group led by Dr Sjoerd van Wijk from the Institute of Experimental Cancer
Research in Paediatrics at 51猎奇 already two years ago found evidence
indicating that the anti-diarrhoea drug loperamide could be used to induce cell
death in glioblastoma cell lines. They have now deciphered its mechanism of
action and, in doing so, are opening new avenues for the development of novel
treatment strategies.
When cells digest themselves
In certain types of tumour cells, administration
of loperamide leads to a stress response in the endoplasmic reticulum (ER), the
cell organelle responsible for key steps in protein synthesis in the body. The
stress in the ER triggers its degradation, followed by self-destruction of the
cells. This mechanism, known as autophagy-dependent cell death occurs when
cells undergo hyperactivated autophagy. Normally, autophagy regulates normal
metabolic processes and breaks down and recycles the valuable parts of damaged
or superfluous cell components thus ensuring the cell鈥檚 survival, for example
in the case of nutrient deficiency. In certain tumour cells, however, hyperactivation
of autophagy destroys so much cell material that they are no longer capable of
surviving.
鈥淥ur experiments with cell lines show that
autophagy could support the treatment of glioblastoma brain tumours,鈥� says van
Wijk. Glioblastoma is a very aggressive and lethal type of cancer in children
and adults that shows only a poor response to chemotherapy. New therapeutic
approaches are therefore urgently required. The research group led by van Wijk
has now identified an important factor that links the ER stress response with
the degradation of the ER (reticulophagy):
The 鈥淎ctivating Transcription Factor鈥� ATF4 is
produced in increased amounts both during ER stress and under the influence of
loperamide. It triggers the destruction of the ER membranes and thus of the ER.
Anti-diarrhoea drug
triggers cell death in glioblastoma cells
鈥淐onversely, if we block ATF4, far fewer
cells in a tumour cell culture die after adding loperamide,鈥� says van Wijk,
describing the control results. In addition, the research group was able to detect
ER debris in loperamide-treated cells under the electron microscope. 鈥淓R
degradation, that is, reticulophagy, visibly contributes to the demise of
glioblastoma cells,鈥� says van Wijk. The team also showed that loperamide triggers
only autophagy but not cell death in other cells, such as embryonic mouse
fibroblasts. 鈥淣ormally, loperamide, when taken as a remedy against diarrhoea,
binds to particular binding sites in the intestine and is not taken up by the
bowel and is therefore harmless鈥�.
Mechanism of action
also applicable to other diseases
The loperamide-induced death of
glioblastoma cells could help in the development of new therapeutic approaches
for the treatment of this severe form of cancer. 鈥淗owever, our findings also
open up exciting new possibilities for the treatment of other diseases where ER
degradation is disrupted, such as neurological disorders or dementia as well as
other types of tumour,鈥� says van Wijk. However, further studies are necessary before
loperamide can actually be used in the treatment of glioblastoma or other
diseases. In future studies it has to be explored, for example, how loperamide
can be transported into the brain and cross the blood-brain barrier.
Nanoparticles might be a feasible option. The research team in Frankfurt now wants
to identify other substances that trigger reticulophagy and examine how the
effect of loperamide can be increased and better understood.
The research group led by Sjoerd van Wijk
is funded by the Frankfurt Foundation for Children with Cancer (Frankfurter
Stiftung f眉r krebskranke Kinder) and the Collaborative Research Centre 1177
鈥淢olecular and Functional Characterisation of Selective Autophagy鈥� funded by
the German Research Foundation (Deutsche Forschungsgemeinschaft). The work is
the result of collaboration with Dr Muriel Mari and Professor Fulvio Reggiori
(University of Groningen, The Netherlands) and Professor Donat K枚gel
(Experimental Neurosurgery, 51猎奇).
Publication:
Svenja Zielke, Simon Kardo, Laura Zein,
Muriel Mari, Adriana Covarrubias-Pinto, Maximilian N. Kinzler, Nina Meyer,
Alexandra Stolz, Simone Fulda, Fulvio Reggiori, Donat K枚gel and Sjoerd van
Wijk: ATF4 links ER stress with
reticulophagy in glioblastoma cells. Taylor & Francis Online
Picture
download:
Caption:
In glioblastoma cells, the antidiarrheal drug
loperamide triggers the degradation of the endoplasmic reticulum. In the normal
state, it is coloured yellow in these microscopic images. In the degradation
state, it glows as a red signal (marked with arrows). Left scale bar: 20 碌m,
right scale bar (inset): 5 碌m (Photos: Svenja Zielke et. al.)
Further
information:
Dr. Sjoerd J. L. van Wijk
Institute of Experimental Cancer Research
in Paediatrics
51猎奇, Frankfurt, Germany
Tel.: +49 69 67866574
s.wijk@kinderkrebsstiftung-frankfurt.de
Dec
21
2020
11:48
Researchers at universities in Frankfurt and T眉bingen have developed and empirically evaluated a new teaching concept for teaching secondary physics.
Newly developed curriculum improves students鈥� understanding of electric circuits in schools
The topic of electricity often poses
difficulties for many secondary school students in physics lessons. Physics
Education Researchers at the 51猎奇 and the University of T眉bingen
have developed and empirically evaluated a new, intuitive curriculum as part of
a major comparative study. The result: not only do secondary school students
gain a better conceptual understanding of electric circuits, but teachers also perceive
the curriculum as a significant improvement in their teaching.
FRANKFURT /
T脺BINGEN. Life without electricity is something that is no longer imaginable.
Whether it be a smartphone, hair-dryer or a ceiling lamp 鈥� the technical
accomplishments we hold dear all require electricity.
Although every child at school learns that electricity can only flow in a
closed electric circuit, what is actually the difference between current and
voltage? Why is a plug socket a potential death-trap but a simple battery is
not? And why does a lamp connected to a power strip not become dimmer when a
second lamp is plugged in?
Research into physics education has
revealed that even after the tenth grade many secondary school students are not
capable of answering such fundamental questions about simple electric circuits
despite their teachers' best efforts. Against this backdrop, Jan-Philipp Burde,
who recently became a junior professor at the University of T眉bingen, in the
framework of his doctoral thesis supervised by Prof. Thomas Wilhelm at 51猎奇,
developed an innovative curriculum for simple electric circuits, which
specifically builds upon the everyday experiences of the students. In contrast
to the approaches taken to date, from the very outset the new curriculum aims
to help students develop an intuitive understanding of voltage. In analogy to air
pressure differences that cause an air stream (e.g. at an inflated air
mattress), voltage is introduced as an 鈥渆lectric pressure difference" that causes
an electric current. A comparative study with 790 school pupils at secondary
schools in Frankfurt showed that the new curriculum led to a significantly
improved understanding of electric circuits compared to traditional physics
tuition. Moreover, the participating teachers also stated that using the new
curriculum fundamentally improved their teaching.
The two researchers from Frankfurt and
T眉bingen have now published a detailed description of the theoretical
considerations underlying the teaching concept in the renowned international
journal 鈥�Physical Review Physics Education Research"
in the framework of the 鈥淔ocused Collection: Theory into Design". The German
Society for Chemistry and Physics Education (GDCP) awarded its
鈥淕DCP-Nachwuchspreis", a prize presented each year for the best dissertation or
post-doctoral thesis in chemistry and physics education in the German-speaking
region, to Burde for his dissertation. As of the winter semester 2019/20 Burde
was appointed to a junior professorship for Physics Education Research supported
by the Vector Foundation at the University of
T眉bingen. On the basis of his work a cross-border consortium encompassing the Universities
T眉bingen, Frankfurt, Darmstadt, Dresden, Graz and Vienna has been constituted
with the objective of making the subject of 鈥渟imple electric circuits" more
interesting and more comprehensible by embedding the topic in contexts from daily
life.
Publications:
Jan-Philipp Burde
and Thomas Wilhelm (2020). Teaching electric circuits with a focus on
potential differences. In: Phys. Rev. Phys. Educ. Res. 16,
020153, DOI:
Jan-Philipp Burde (2018): Konzeption
und Evaluation eines Unterrichtskonzepts zu einfachen Stromkreisen auf Basis
des Elektronengasmodells. Studien zum Physik- und Chemielernen, Band 259,
Logos-Verlag, Berlin, ISBN: 978-3-8325-4726-4,
Picture
download:
Caption:
Jun.-Prof. Dr. Jan-Philipp Burde, University of T眉bingen. Photo: Friedhelm
Albrecht for University of T眉bingen
Caption: Prof. Dr. Thomas Wilhelm, 51猎奇 Frankfurt. Photo: Felix Richter
Further
Information:
Prof. Dr. Thomas Wilhelm
Executive Director
Department of Physics Education Research
51猎奇 Frankfurt
Phone: +49 69 798-47845
wilhelm@physik.uni-frankfurt.de
Jun.-Prof. Dr. Jan-Philipp Burde
Physics Education Research Group
University of T眉bingen
Phone: +49 7071 29 78651
jan-philipp.burde@uni-tuebingen.de
Dec
16
2020
14:59
The Indian writer will talk in the lecture series In Transit|ion.聽
Arundhati Roy to read at 51猎奇
On 22 January, the Indian writer Arundhati Roy will be the featured guest speaker in the renowned "In Transit|ion" lecture series at 51猎奇 Frankfurt. The series is an international and transdisciplinary programme offered by the Institute of English and American Studies at 51猎奇 Frankfurt. In the Zoom event:
"The syntax of everyday injustice" on 22.01.2021
10:00h - 12:00h CET (Central European Time)
14:30h - 16:30h IST (India Standard Time)
Roy will read from her new work, forms the
basis for the subsequent discussion, moderated by Dr. Pavan Malreddy,
research associate at the Institute of English and American Studies. The event
will be held in English.
Arundhati Roy is the author of the award-winning bestseller "The God of Small Things," published in 1997, in which she writes of the connections between the caste system, class society, capitalism and imperialism. In the years between the publication of her first and second critically acclaimed novel, which appeared two decades later, she mainly wrote literary and political essays and confronted Indian society on a variety of topics: religious persecution, economic inequalities, caste and class hierarchies, the exploitation of natural resources and the resulting expropriation of small farmers in the name of development.
Her extensive non-fiction work including "The Politics of Power," and "From the Workshop of Democracy," and her second novel "The Ministry of Extreme Happiness" explain how capitalism and privatisation undermine democracy, destroy the environment and irreversibly accelerate climate change. Both her novels and her non-fiction work are the subject of lively, sometimes heated, scientific debates both inside and outside India. Her works are read today in more than forty languages.
Roy is an outspoken critic of communalism and majoritarianism in Indian
politics. Her concise analysis of grassroots fascism and the ideological
breeding ground it needs to flourish in Indian society and elsewhere forms the
basis of her most recent work "Azadi - Freedom, Fascism, Fiction" (2020).
The lecture series
"In Transit|ion - Frankfurt Lectures in Literary and Cultural
Studies" is an international and transdisciplinary series organised by
the Institute of English and American Studies at 51猎奇 Frankfurt.
Twice a semester, leading writers and scholars from the English-speaking world
present their work in the fields of American Studies, English Studies and
Anglophone Literatures and Cultures. Since its inception in 2016, the series
has featured speakers from top international universities in Great Britain
(Oxford, Cambridge), the U.S. (Columbia, Chicago), Australia (Monash
University) and India (North Bengal).
Please register for the event
by e-mail: pavanmalreddy@protonmail.com
Further information:
Dr. Pavan Malreddy, New English Literatures and Cultures (NELK) &
Frankfurt Memory Studies Platform (FMSP)
51猎奇 Frankfurt am
Main.
malreddy@em.uni-frankfurt.de;
Dec
14
2020
16:54
Research team from 51猎奇 and TU Munich involved
How matter holds together: ALICE researchers prepare the way for precision studies of the strong interaction
Extremely dense neutron
stars may contain unstable hyperons in their interior, which, like the stable
hadrons of the atomic nucleus, protons and neutrons, are held together by the strong
interaction. Scientists from the ALICE collaboration at the accelerator centre
CERN have now developed a method to precisely measure the strong interaction
between unstable hadrons in experiments for the first time. Research teams from
51猎奇 headed by Professor Harald Appelsh盲user and TU Munich headed by Professor Laura
Fabbietti were involved in the development.
FRANKFURT. In an article published
today in Nature, the ALICE collaboration describes a novel method that will
allow precision measurements of the strong interaction between hadrons at the
Large Hadron Collider (LHC) accelerator at CERN in Geneva.
Hadrons - which include
protons and neutrons - are particles composed of two or three quarks, which are
held together by the strong interaction. However, the interaction is not
limited to the interior of the hadron, but extends beyond it. It leads to something
known as residual interaction, due to which hadrons also exert forces on each
other. The best-known example is the force between protons and neutrons, which
is responsible for the cohesion of atomic nuclei. One of the great challenges
of modern nuclear physics is to achieve an accurate calculation of the strong
force between hadrons, which is based on the underlying strong interaction of
quarks.
Within the framework of something
known as "lattice QCD" calculations, the effective strong force
between hadrons can be calculated on the basis of the fundamental theory of the
strong interaction between quarks. However, these calculations are only very
accurate for hadrons containing heavy quarks. This applies, for example, to
hyperons, i.e. hadrons that contain one or more strange quarks. Although the
strong interaction caused by collisions of hadrons can be studied in scattering
experiments, it is difficult to perform these experiments with unstable hadrons
such as hyperons. Accordingly, an experimental comparison with the precise
theoretical predictions from the lattice QCD for hyperons is difficult.
In today's publication
of the ALICE collaboration a method is presented which allows the study of the
dynamics of the strong interaction for arbitrary pairs of hadrons. This
concerns especially those hadrons which are short-lived, i.e. which decay after
fractions of seconds and therefore cannot be investigated in scattering
experiments. Instead, the hadrons are generated in proton-proton collisions at
the LHC. The interaction between them can be measured on the basis of their
relative momentum distribution.
Professor Laura Fabbietti
from the TU Munich, who has contributed significantly to the results presented
here, emphasises that this breakthrough is due to both the LHC and the ALICE
detector. The LHC is able to generate a very large number of hadrons with
strange quarks and thus provides an insight into the nature of the strong
interaction. The ALICE detector and its high-resolution Time Projection Chamber
(TPC), in turn, would provide the necessary precision to identify the particles
accurately and measure their momentum accurately.
Harald Appelsh盲user,
professor at 51猎奇, has been leading the ALICE TPC project for
ten years and is co-author of the publication. He works closely with Laura
Fabbietti's Munich group and emphasises that the method presented would usher
in "a new era of precision studies of the strong interaction between exotic
hadrons at the LHC."
The method presented is
called femtoscopy because the processes examined take place in a spatial area
of about 1 femtometre (10-15metres). This corresponds approximately to the size of a
hadron and the range of the strong interaction. Using this method, the ALICE
collaboration has already been able to study interactions between hyperons
containing one or two strange quarks. In today's publication, a measurement of
the interaction between a proton and the omega (惟) hyperon has now been
investigated for the first time and with high precision. The omega is the
rarest of all hyperons and consists of three strange quarks.
Professor Appelsh盲user
emphasises that the significance of the results goes beyond the verification of
theoretical calculations: "Femtoscopic investigations can significantly
expand our understanding of very dense stellar objects such as neutron stars,
which can contain hyperons in their interior and whose interaction is still
largely unknown."
Publication: Shreyasi Acharya et al. (ALICE
Collaboration): Unveiling the strong interaction among hadrons at the
LHC. Nature, 9. December 2020 鈥�
Explanatory video by TU Munich on this subject:
Images may be downloaded here:
Caption: In the future, hyperons will be measured at the ALICE detector of the CERN particle accelerator centre. Scientists from 51猎奇 are part of the ALICE collaboration. Credit: CERN
Further information
Prof.
Dr. Harald Appelsh盲user
Institute for Nuclear Physics
51猎奇 Frankfurt
Phone: +49 69 798-47034 or 47023
appels@ikf.uni-frankfurt.de