251 research outputs found
Entwicklung von Verfahren zur Herstellung von Urankarbiden sowie Cermets auf UC-Basis. EUR 355. = Development of methods for the production of uranium carbides and cermets on UC basis. EUR 355.
Empathy and correct mental state inferences both promote prosociality
In a world with rapidly increasing population that competes for the earth's limited resources, cooperation is crucial. While research showed that empathizing with another individual in need enhances prosociality, it remains unclear whether correctly inferring the other's inner, mental states on a more cognitive level (i.e., mentalizing) elicits helping behavior as well. We applied a video-based laboratory task probing empathy and a performance measure of mentalizing in adult volunteers (N = 94) and assessed to which extent they were willing to help the narrators in the videos. We replicate findings that an empathy induction leads to more prosocial decisions. Crucially, we also found that correct mentalizing increases the willingness to help. This evidence helps clarify an inconsistent picture of the relation between mentalizing and prosociality
Augmented reality-guided pelvic osteotomy of Ganz: feasibility in cadavers
INTRODUCTION
The periacetabular osteotomy is a technically demanding procedure with the goal to improve the osseous containment of the femoral head. The options for controlled execution of the osteotomies and verification of the acetabular reorientation are limited. With the assistance of augmented reality, new possibilities are emerging to guide this intervention. However, the scientific knowledge regarding AR navigation for PAO is sparse.
METHODS
In this cadaveric study, we wanted to find out, if the execution of this complex procedure is feasible with AR guidance, quantify the accuracy of the execution of the three-dimensional plan, and find out what has to be done to proceed to real surgery. Therefore, an AR guidance for the PAO was developed and applied on 14 human hip cadavers. The guidance included performance of the four osteotomies and reorientation of the acetabular fragment. The osteotomy starting points, the orientation of the osteotomy planes, as well as the reorientation of the acetabular fragment were compared to the 3D planning.
RESULTS
The mean 3D distance between planned and performed starting points was between 9 and 17 mm. The mean angle between planned and performed osteotomies was between 6° and 7°. The mean reorientation error between the planned and performed rotation of the acetabular fragment was between 2° and 11°.
CONCLUSION
The planned correction can be achieved with promising accuracy and without serious errors. Further steps for a translation from the cadaver to the patient have been identified and must be addressed in future work
Probing two topological surface bands of Sb2Te3 by spin-polarized photoemission spectroscopy
Using high resolution spin- and angle-resolved photoemission spectroscopy, we
map the electronic structure and spin texture of the surface states of the
topological insulator Sb2Te3. In combination with density functional
calculations (DFT), we directly show that Sb2Te3 exhibits a partially occupied,
single spin-Dirac cone around the Fermi energy, which is topologically
protected. DFT obtains a spin polarization of the occupied Dirac cone states of
80-90%, which is in reasonable agreement with the experimental data after
careful background subtraction. Furthermore, we observe a strongly spin-orbit
split surface band at lower energy. This state is found at 0.8eV below the
Fermi level at the gamma-point, disperses upwards, and disappears at about
0.4eV below the Fermi level into two different bulk bands. Along the gamma-K
direction, the band is located within a spin-orbit gap. According to an
argument given by Pendry and Gurman in 1975, such a gap must contain a surface
state, if it is located away from the high symmetry points of the Brillouin
zone. Thus, the novel spin-split state is protected by symmetry, too.Comment: 8 pages, 10 figure
Two-body quantum mechanical problem on spheres
The quantum mechanical two-body problem with a central interaction on the
sphere is considered. Using recent results in representation
theory an ordinary differential equation for some energy levels is found. For
several interactive potentials these energy levels are calculated in explicit
form.Comment: 41 pages, no figures, typos corrected; appendix D was adde
Augmented Reality Based Surgical Navigation of Complex Pelvic Osteotomies
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Open AccessArticle
Augmented Reality Based Surgical Navigation of Complex Pelvic Osteotomies—A Feasibility Study on Cadavers
by Joëlle Ackermann
1,2,† [ORCID] , Florentin Liebmann
1,2,*,† [ORCID] , Armando Hoch
3 [ORCID] , Jess G. Snedeker
2,3, Mazda Farshad
3, Stefan Rahm
3, Patrick O. Zingg
3 and Philipp Fürnstahl
1
1
Research in Orthopedic Computer Science, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland
2
Laboratory for Orthopaedic Biomechanics, ETH Zurich, 8093 Zurich, Switzerland
3
Department of Orthopedics, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Academic Editor: Jiro Tanaka
Appl. Sci. 2021, 11(3), 1228; https://doi.org/10.3390/app11031228
Received: 20 December 2020 / Revised: 13 January 2021 / Accepted: 25 January 2021 / Published: 29 January 2021
(This article belongs to the Special Issue Artificial Intelligence (AI) and Virtual Reality (VR) in Biomechanics)
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Abstract
Augmented reality (AR)-based surgical navigation may offer new possibilities for safe and accurate surgical execution of complex osteotomies. In this study we investigated the feasibility of navigating the periacetabular osteotomy of Ganz (PAO), known as one of the most complex orthopedic interventions, on two cadaveric pelves under realistic operating room conditions. Preoperative planning was conducted on computed tomography (CT)-reconstructed 3D models using an in-house developed software, which allowed creating cutting plane objects for planning of the osteotomies and reorientation of the acetabular fragment. An AR application was developed comprising point-based registration, motion compensation and guidance for osteotomies as well as fragment reorientation. Navigation accuracy was evaluated on CT-reconstructed 3D models, resulting in an error of 10.8 mm for osteotomy starting points and 5.4° for osteotomy directions. The reorientation errors were 6.7°, 7.0° and 0.9° for the x-, y- and z-axis, respectively. Average postoperative error of LCE angle was 4.5°. Our study demonstrated that the AR-based execution of complex osteotomies is feasible. Fragment realignment navigation needs further improvement, although it is more accurate than the state of the art in PAO surgery
Power-law spin correlations in pyrochlore antiferromagnets
The ground state ensemble of the highly frustrated pyrochlore-lattice
antiferromagnet can be mapped to a coarse-grained ``polarization'' field
satisfying a zero-divergence condition From this it follows that the
correlations of this field, as well as the actual spin correlations, decay with
separation like a dipole-dipole interaction (). Furthermore, a lattice
version of the derivation gives an approximate formula for spin correlations,
with several features that agree well with simulations and neutron-diffraction
measurements of diffuse scattering, in particular the pinch-point
(pseudo-dipolar) singularities at reciprocal lattice vectors. This system is
compared to others in which constraints also imply diffraction singularities,
and other possible applications of the coarse-grained polarization are
discussed.Comment: 13 pp, revtex, two figure
Exact results of the mixed-spin Ising model on a decorated square lattice with two different decorating spins of integer magnitudes
The mixed-spin Ising model on a decorated square lattice with two different
decorating spins of the integer magnitudes S_B = 1 and S_C = 2 placed on
horizontal and vertical bonds of the lattice, respectively, is examined within
an exact analytical approach based on the generalized decoration-iteration
mapping transformation. Besides the ground-state analysis, finite-temperature
properties of the system are also investigated in detail. The most interesting
numerical result to emerge from our study relates to a striking critical
behaviour of the spontaneously ordered 'quasi-1D' spin system. It was found
that this quite remarkable spontaneous order arises when one sub-lattice of the
decorating spins (either S_B or S_C) tends towards their 'non-magnetic' spin
state S = 0 and the system becomes disordered only upon further single-ion
anisotropy strengthening. The effect of single-ion anisotropy upon the
temperature dependence of the total and sub-lattice magnetization is also
particularly investigated.Comment: 17 pages, 6 figure
Decolonisation of MRSA, S. aureus and E. coli by Cold-Atmospheric Plasma Using a Porcine Skin Model In Vitro
In the last twenty years new antibacterial agents approved by the U.S. FDA decreased whereas in parallel the resistance situation of multi-resistant bacteria increased. Thus, community and nosocomial acquired infections of resistant bacteria led to a decrease in the efficacy of standard therapy, prolonging treatment time and increasing healthcare costs. Therefore, the aim of this work was to demonstrate the applicability of cold atmospheric plasma for decolonisation of Gram-positive (Methicillin-resistant Staphylococcus aureus (MRSA), Methicillin-sensitive Staphylococcus aureus) and Gram-negative bacteria (E. coli) using an ex vivo pig skin model. Freshly excised skin samples were taken from six month old female pigs (breed: Pietrain). After application of pure bacteria on the surface of the explants these were treated with cold atmospheric plasma for up to 15 min. Two different plasma devices were evaluated. A decolonisation efficacy of 3 log10 steps was achieved already after 6 min of plasma treatment. Longer plasma treatment times achieved a killing rate of 5 log10 steps independently from the applied bacteria strains. Histological evaluations of untreated and treated skin areas upon cold atmospheric plasma treatment within 24 h showed no morphological changes as well as no significant degree of necrosis or apoptosis determined by the TUNEL-assay indicating that the porcine skin is still vital. This study demonstrates for the first time that cold atmospheric plasma is able to very efficiently kill bacteria applied to an intact skin surface using an ex vivo porcine skin model. The results emphasize the potential of cold atmospheric plasma as a new possible treatment option for decolonisation of human skin from bacteria in patients in the future without harming the surrounding tissue
Phase I study of dose-escalated paclitaxel, ifosfamide, and cisplatin (PIC) combination chemotherapy in advanced solid tumours
Based on the already known in vitro synergy between paclitaxel (taxol), cisplatin and oxazophosphorine cytostatics and the broad spectrum of activity of the above drugs we sought to evaluate the paclitaxel (taxol)-ifosfamide-cisplatin (PIC) combination in the outpatient setting in individuals with a variety of advanced solid tumours. Cohorts of patients were entered into six successive dose levels (DLs) with drug doses ranging as follows: paclitaxel 135–215 mg m−2day 1 – (1 h infusion), ifosfamide 4.5–6.0 g m−2(total dose) – divided over days 1 and 2, and cisplatin 80–100 mg m−2(total) – divided over days 1 and 2. Granulocyte colony-stimulating factor was given from day 5 to 14. Forty-two patients were entered. Eighteen patients had 2–8 cycles of prior chemotherapy with no taxanes or ifosfamide (cisplatin was allowed). The regimen was tolerated with outpatient administration in 36/42 patients. Toxicities included: grade 4 neutropenia for ≤ 5 days in 27% of cycles; 5 episodes of febrile neutropenia in three patients at DL-III, -V and -VI. Grade 3/4 thrombocytopenia and cumulative grade 3 anaemia were seen in 7% and 13% of cycles respectively. Three cases of severe grade 3 neuromotor/sensory neuropathy were recorded at DL-II, -III, and -V, all after cycle 3. The maximum tolerated dose was not formally reached at DL-V, but because of progressive anaemia and asthenia/fatigue, it was decided to test a new DL-VI with doses of paclitaxel 200 mg m−2, ifosfamide 5.0 g m−2and cisplatin 100 mg m−2; this appeared to be tolerable and is recommended for further phase II testing. The response rate was 47.5% (complete response + partial response: 20/42). The PIC regimen appears to be feasible and safe in the outpatient setting. Care should be paid to neurotoxicity. Phase II studies are starting in non-small-cell lung cancer, ovarian cancer and head and neck cancer at DL-VI. © 2000 Cancer Research Campaig
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