Gold Nanoparticles Bioproduced in Cyanobacteria in the Initial Phase Opened an Avenue for the Discovery of Corresponding Cerium Nanoparticles

The production of isolated metallic nanoparticles with multifunctionalized properties, such as size and shape, is crucial for biomedical, photocatalytic, and energy storage or remediation applications. This study investigates the initial particle formations of gold nanoparticles (AuNPs) bioproduced in the cyanobacteria Anabaena sp. using high-resolution transmission electron microscopy images for digital image analysis. The developed method enabled the discovery of cerium nanoparticles (CeNPs), which were biosynthesized in the cyanobacteria Calothrix desertica. The particle size distributions for AuNPs and CeNPs were analyzed. After 10 h, the average equivalent circular diameter for AuNPs was 4.8 nm, while for CeNPs, it was approximately 5.2 nm after 25 h. The initial shape of AuNPs was sub-round to round, while the shape of CeNPs was more roundish due to their amorphous structure and formation restricted to heterocysts. The local PSDs indicate that the maturation of AuNPs begins in the middle of vegetative cells and near the cell membrane, compared to the other regions of the cell.

Time-Dependent Size and Shape Evolution of Gold and Europium Nanoparticles from a Bioproducing Microorganism, a Cyanobacterium: A Digitally Supported High-Resolution Image Analysis

Herein, the particle size distributions (PSDs) and shape analysis of in vivo bioproduced particles from aqueous Au³⁺ and Eu³⁺ solutions by the cyanobacterium Anabaena sp. are examined in detail at the nanoscale. Generally, biosynthesis is affected by numerous parameters. Therefore, it is challenging to find the key set points for generating tailored nanoparticles (NPs). PSDs and shape analysis of the Au and Eu-NPs were performed with ImageJ using high-resolution transmission electron microscopy (HR-TEM) images. As the HR-TEM image analysis reflects only a fraction of the detected NPs within the cells, additional PSDs of the complete cell were performed to determine the NP count and to evaluate the different accuracies. Furthermore, local PSDs were carried out at five randomly selected locations within a single cell to identify local hotspots or agglomerations. The PSDs show that particle size depends mainly on contact time, while the particle shape is hardly affected. The particles formed are distributed quite evenly within the cells. HR-PSDs for Au-NPs show an average equivalent circular diameter (ECD) of 8.4 nm (24 h) and 7.2 nm (51 h). In contrast, Eu-NPs preferably exhibit an average ECD of 10.6 nm (10 h) and 12.3 nm (244 h). Au-NPs are classified predominantly as "very round" with an average reciprocal aspect ratio (RAR) of ~0.9 and a Feret major axis ratio (FMR) of ~1.17. Eu-NPs mainly belong to the "rounded" class with a smaller RAR of ~0.6 and a FMR of ~1.3. These results show that an increase in contact time is not accompanied by an average particle growth for Au-NPs, but by a doubling of the particle number. Anabaena sp. is capable of biosorbing and bioreducing dissolved Au³⁺ and Eu³⁺ ions from aqueous solutions, generating nano-sized Au and Eu particles, respectively. Therefore, it is a low-cost, non-toxic and effective candidate for a rapid recovery of these sought-after metals via the bioproduction of NPs with defined sizes and shapes, providing a high potential for scale-up.

High-resolution particle size and shape analysis of the first Samarium nanoparticles biosynthesized from aqueous solutions via cyanobacteria Anabaena cylindrica

Samarium (Sm) is one of the most sought-after rare earth metals. Price trends and dwindling resources are making recovery increasingly attractive. In this context, the use of cyanobacteria is highly promising. For Sm it was unclear whether Anabaena cylindrica produces particles through metabolically active Sm³⁺ uptake. High-resolution (HR) imaging now clearly demonstrates microbe generated biosynthesis of Sm nano-sized particles (Sm NPs) in vivo. Furthermore, a simple method to determine particle size and shape with high accuracy is presented. Digital image analysis with ImageJ of HR-TEMs is used to characterize Sm NPs revealing a nearly uniform local size distribution. Assuming round particles, the overall average area size is 135.5 nm², resp. 11.9 nm diameter. In HR, where different cell sections of the same cell are averaged, the mean particle is smaller, 76.7 nm² resp. 8.9 nm diameter. The reciprocal aspect ratio is 0.63. The Feret major axis ratio is calculated as shape factor, with 35% of the particles between 1.2 and 1.4. A roundness classification shows that 38% of particles are fairly round and 41% are very round. Consequently, A. cylindrica represents a suitable microorganism for possible Sm recovery and biosynthesis of roundish nano-sized particles.

Plasma Supported Deposition of Amorphous Hydrogenated Carbon (a-C:H) on Polyamide 6: Determining Interlayer Completion and Dehydrogenation Effects during Layer Growth

Polyamide 6 (PA6) is a commonly used material in many different sectors of modern industry. Herein, PA6 samples were coated with amorphous carbon layers (a-C:H) with increasing thickness up to 2 µm using radio frequency plasma enhanced chemical vapor deposition for surface adjustment. The morphology of the carbon coatings was inspected by ex situ atomic force microscopy and scanning electron microscopy. Surface wettability was checked by contact angle measurements. The chemical composition was analyzed using the surface sensitive synchrotron X-ray-based techniques near-edge X-ray absorption fine structure and X-ray photoelectron spectroscopy, supported by diffuse reflectance infrared Fourier transform spectroscopy. Particular attention was paid to the coating interval from 0 to 100 nm, to specify the interlayer thickness between the PA6 polymer and a-C:H coating, and the region between 1000 and 2000 nm, where dehydrogenation of the a-C:H layer occurs. The interlayer is decisive for the linkage of the deposited carbon layer on the polymer: the more pronounced it is, the better the adhesion. The thickness of the interlayer could be narrowed down to 40 nm in all used methods, and the dehydrogenation process takes place at a layer thickness of 1500 nm.

Realization of a multinode quantum network of remote solid-state qubits

The distribution of entangled states across the nodes of a future quantum internet will unlock fundamentally new technologies. Here, we report on the realization of a three-node entanglement-based quantum network. We combine remote quantum nodes based on diamond communication qubits into a scalable phase-stabilized architecture, supplemented with a robust memory qubit and local quantum logic. In addition, we achieve real-time communication and feed-forward gate operations across the network. We demonstrate two quantum network protocols without postselection: the distribution of genuine multipartite entangled states across the three nodes and entanglement swapping through an intermediary node. Our work establishes a key platform for exploring, testing, and developing multinode quantum network protocols and a quantum network control stack.

Comparing the Influence of Residual Stress on Composite Materials Made of Polyhydroxybutyrate (PHB) and Amorphous Hydrogenated Carbon (a-C:H) Layers: Differences Caused by Single Side and Full Substrate Film Attachment during Plasma Coating

Polyhydroxybutyrate (PHB) is a bio-based, biodegradable and commercially used polymer, which in its native form is unfortunately not generally applicable. A widely used technique to adapt polymers to a wider range of applications is the surface modification with amorphous hydrogenated carbon (a-C:H) layers, realized by plasma-enhanced chemical vapor deposition (PE-CVD). However, this process creates intrinsic stress in the layer–polymer system which can even lead to full layer failure. The aim of this study was to investigate how the carbon layer is affected when the basic polymer film to be coated can follow the stress and bend (single side attachment) and when it cannot do so because it is firmly clamped (full attachment). For both attachment methods, the a-C:H layers were simultaneously deposited on PHB samples. Ex-situ characterization was performed using a scanning electron microscope (SEM) for surface morphology and contact angle (CA) measurements for wettability. In addition, the stress prevailing in the layer was calculated using the Stoney equation. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) measurements were used to investigate the chemical composition of the coating surface.

Reaction-diffusion fronts and the butterfly set

A single-species reaction-diffusion model is used for studying the coexistence of multiple stable steady states. In these systems, one can define a potential-like functional that contains the stability properties of the states, and the essentials of the motion of wave fronts in one- and two-dimensional space. Using a quintic polynomial for the reaction term and taking advantage of the well-known butterfly bifurcation, we analyze the different scenarios involving the competition of two and three stable steady states, based on equipotential curves and points in parameter space. The predicted behaviors, including a front splitting instability, are contrasted to numerical integrations of reaction fronts in two dimensions.

Competing ternary surface reaction CO + O2 + H2 on Ir(111)

The CO oxidation on platinum-group metals under ultra-high-vacuum conditions is one of the most studied surface reactions. However, the presence of disturbing species and competing reactions are often neglected. One of the most interesting additional gases to be treated is hydrogen, due to its importance in technical applications and its inevitability under vacuum conditions. Adding hydrogen to the reaction of CO and O₂ leads to more adsorbed species and competing reaction steps towards water formation. In this study, a model for approaching the competing surface reactions CO+O ₂ + H₂ is presented and discussed. Using the framework of bifurcation theory, we show how the steady states of the extended system correspond to a swallowtail catastrophe set with a tristable regime within the swallowtail. We explore numerically the possibility of reaching all stable states and illustrate the experimental challenges such a system could pose. Lastly, an approximative first-principle approach to diffusion illustrates how up to three stable states balance each other while forming heterogeneous patterns.

Cyanobacterial promoted enrichment of rare earth elements europium, samarium and neodymium and intracellular europium particle formation

In the recovery of rare earth elements (REE) microbial biosorption has shown its theoretical ability as an extremely economically and environmentally friendly production method in the last few years. To evaluate the ability of two cyanobacterial strains, namely Anabaena spec. and Anabaena cylindrica to enrich dissolved trivalent REE, a simple protocol was followed. The REE tested in this study include some of the most prominent representatives, such as europium (Eu), samarium (Sm) and neodymium (Nd). Within the experiments, a fast decrease of the REE³⁺ concentration in solution was tracked by inductively coupled plasma mass spectrometry (ICP-MS). It revealed an almost complete (>99%) biosorption of REE³⁺ within the first hour after the addition of metal salts. REE³⁺ uptake by biomass was checked using laser-induced breakdown spectroscopy (LIBS) and showed that all three selected REE³⁺ species were enriched in the cyanobacterial biomass and the process is assigned to a biosorption process. Although the biomass stayed alive during the experiments, up to that, a distinction whether the REE³⁺ was intra- or extracellularly sorbed was not possible, since biosorption is a metabolism independent process which occurs on living as well as non-living biomass. For europium it was shown by TEM that electron dense particles, presumably europium particles with particle sizes of about 15 nm, are located inside the vegetative cyanobacterial cells. This gave clear evidence that Eu³⁺ was actively sorbed by living cyanobacteria. Eu³⁺ biosorption by cell wall precipitation due to interaction with extracellular polysaccharides (EPS) could therefore be excluded. Finally, with XRD analysis it was shown that the detected europium particles had an amorphous instead of a crystalline structure. Herein, we present a fast biosorptive enrichment of the rare earth elements europium, samarium and neodymium by Anabaena spec. and Anabaena cylindrica and for the first time the subsequent formation of intracellular europium particles by Anabaena spec.

Efficient biosorption and intracellular accumulation of selected rare earth elements from aqueous solutions by cyanobacteria type Anabaena.

Detailed analysis of transitions in the CO oxidation on palladium(111) under noisy conditions

It has been shown that CO oxidation on Pd(111) under ultrahigh vacuum conditions can suffer rare transitions between two stable states triggered by weak intrinsic perturbations. Here we study the effects of adding controlled noise by varying the concentrations of O₂ and CO that feed the vacuum chamber, while the total flux stays constant. In addition to the regime of rare transitions between states of different CO₂ reaction rates induced by intrinsic fluctuations, we found three distinct effects of external noise depending on its strength: small noise suppresses transitions and stabilizes the upper rate state; medium noise induces bursting; and large noise gives rise to reversible transitions in both directions. To explain some of the features present in the dynamics, we propose an extended stochastic model that includes a global coupling through the gas phase to account for the removal of CO gas caused by the adsorption of the Pd surface. The numerical simulations based in the model show a qualitative agreement with the noise-induced transitions found in experiments, but suggest that more complex spatial phenomena are present in the observed fluctuations.

A universal test for gravitational decoherence

Quantum mechanics and the theory of gravity are presently not compatible. A particular question is whether gravity causes decoherence. Several models for gravitational decoherence have been proposed, not all of which can be described quantum mechanically. Since quantum mechanics may need to be modified, one may question the use of quantum mechanics as a calculational tool to draw conclusions from the data of experiments concerning gravity. Here we propose a general method to estimate gravitational decoherence in an experiment that allows us to draw conclusions in any physical theory where the no-signalling principle holds, even if quantum mechanics needs to be modified. As an example, we propose a concrete experiment using optomechanics. Our work raises the interesting question whether other properties of nature could similarly be established from experimental observations alone—that is, without already having a rather well-formed theory of nature to make sense of experimental data.

Whether gravity causes decoherence is a natural question on the way of making quantum physics compatible with the theory of gravity. Here the authors devise a general method to estimate gravitational decoherence in any no-signalling physical theory, which holds even if quantum mechanics would be modified.

Morphological and Chemical Evolution of Gradually Deposited Diamond-Like Carbon Films on Polyethylene Terephthalate: From Subplantation Processes to Structural Reorganization by Intrinsic Stress Release Phenomena

Diamond-like carbon (DLC) films on polyethylene terephthalate (PET) are nowadays intensively studied composites due to their excellent gas barrier properties and biocompatibility. Despite their applicative features being highly explored, the interface properties and structural film evolution of DLC coatings on PET during deposition processes are still sparsely investigated. In this study two different types of DLC films were gradually deposited on PET by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) using acetylene plasma. The surface morphology of the deposited samples has been analyzed by atomic force microscopy (AFM). Their chemical composition was investigated by diffusive reflectance infrared Fourier transform (DRIFT) and Raman spectroscopy analysis and the surface wettability by contact angle measurements. Subplantation processes and interface effects are revealed through the morphological and chemical analysis of both types. During plasma deposition processes the increasing carbon load causes the rise of intrinsic film stress. It is proven that stress release phenomena cause the transition between polymer-like to a more cross-linked DLC network by folding dehydrogenated chains into closed 6-fold rings. These findings significantly lead to an enhanced understanding in DLC film growth mechanism by RF-PECVD processes.

Time-dependent growth of crystalline Au(0)-nanoparticles in cyanobacteria as self-reproducing bioreactors: 2. Anabaena cylindrica

Microbial biosynthesis of metal nanoparticles as needed in catalysis has shown its theoretical ability as an extremely environmentally friendly production method in the last few years, even though the separation of the nanoparticles is challenging. Biosynthesis, summing up biosorption and bioreduction of diluted metal ions to zero valent metals, is especially ecofriendly, when the bioreactor itself is harmless and needs no further harmful reagents. The cyanobacterium Anabaena cylindrica (SAG 1403.2) is able to form crystalline Au(0)-nanoparticles from Au(3+) ions and does not release toxic anatoxin-a. X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and laser-induced breakdown spectroscopy (LIBS) are applied to monitor the time-dependent development of gold nanoparticles for up to 40 hours. Some vegetative cells (VC) are filled with nanoparticles within minutes, while the extracellular polymeric substances (EPS) of vegetative cells and the heterocyst polysaccharide layer (HEP) are the regions, where the first nanoparticles are detected on most other cells. The uptake of gold starts immediately after incubation and within four hours the average size remains constant around 10 nm. Analyzing the TEM images with an image processing program reveals a wide distribution for the diameter of the nanoparticles at all times and in all regions of the cyanobacteria. Finally, the nanoparticle concentration in vegetative cells of Anabaena cylindrica is about 50% higher than in heterocysts (HC). These nanoparticles are found to be located along the thylakoid membranes.

In vitro evaluation of novel antimicrobial coatings for surgical sutures using octenidine

BACKGROUND

Sutures colonized by bacteria represent a challenge in surgery due to their potential to cause surgical site infections. In order to reduce these type of infections antimicrobially coated surgical sutures are currently under development. In this study, we investigated the antimicrobial drug octenidine as a coating agent for surgical sutures. To achieve high antimicrobial efficacy and required biocompatibility for medical devices, we focused on optimizing octenidine coatings based on fatty acids. For this purpose, antimicrobial sutures were prepared with either octenidine-laurate or octenidine-palmitate at 11, 22, and 33 μg/cm drug concentration normalized per length of sutures. Octenidine containing sutures were compared to the commercial triclosan-coated suture Vicryl® Plus. The release of octenidine into aqueous solution was analyzed and long-term antimicrobial efficacy was assessed via agar diffusion tests using Staphylococcus aureus. For determining biocompatibility, cytotoxicity assays (WST-1) were performed using L-929 mouse fibroblasts.

RESULTS

In a 7 days elution experiment, octenidine-palmitate coated sutures demonstrated much slower drug release (11 μg/cm: 7%; 22 μg/cm: 5%; 33 μg/cm: 33%) than octenidine-laurate sutures (11 μg/cm: 82%; 22 μg/cm: 88%; 33 μg/cm: 87%). Furthermore sutures at 11 μg/cm drug content were associated with acceptable cytotoxicity according to ISO 10993-5 standard and showed, similar to Vicryl® Plus, relevant efficacy to inhibit surrounding bacterial growth for up to 9 days.

CONCLUSIONS

Octenidine coated sutures with a concentration of 11 μg/cm revealed high antimicrobial efficacy and biocompatibility. Due to their delayed release, palmitate carriers should be preferred. Such coatings are candidates for clinical testing in regard to their safety and efficacy.

Effects of macrophage-dependent peroxisome proliferator-activated receptor γ signalling on adhesion formation after abdominal surgery in an experimental model

BACKGROUND

The pathophysiology of adhesion formation after abdominal and pelvic surgery is still largely unknown. The aim of the study was to investigate the role of macrophage polarization and the effect of peroxisome proliferator-activated receptor (PPAR) γ stimulation on adhesion formation in an animal model.

METHODS

Peritoneal adhesion formation was induced by the creation of ischaemic buttons within the peritoneal wall and the formation of a colonic anastomosis in wild-type, interleukin (IL) 10-deficient (IL-10(-/-) ), IL-4-deficient (IL-4(-/-) ) and CD11b-Cre/PPARγ(fl) (/fl) mice. Adhesions were assessed at regular intervals, and cell preparations were isolated from ischaemic buttons and normal peritoneum. These samples were analysed for macrophage differentiation and its markers, and expression of cytokines by quantitative PCR, fluorescence microscopy, arginase activity and pathological examination. Some animals underwent pioglitazone (PPAR-γ agonist) or vehicle treatment to inhibit adhesion formation. Anastomotic healing was evaluated by bursting pressure measurement and collagen gene expression.

RESULTS

Macrophage M2 marker expression and arginase activity were raised in buttons without adhesions compared with buttons with adhesions. IL-4(-/-) and IL-10(-/-) mice were not affected, whereas CD11b-Cre/PPARγ(fl) (/fl) mice showed decreased arginase activity and increased adhesion formation. Perioperative pioglitazone treatment increased arginase activity and decreased adhesion formation in wild-type but not CD11b-Cre/PPARγ(fl) (/fl) mice. Pioglitazone had no effect on anastomotic healing.

CONCLUSION

Endogenous macrophage-specific PPAR-γ signalling affected arginase activity and macrophage polarization, and counter-regulated peritoneal adhesion manifestation. Pharmacological PPAR-γ agonism induced a shift towards macrophage M2 polarization and ameliorated adhesion formation in a macrophage-dependent manner. Surgical relevance Postoperative adhesion formation is frequently seen after abdominal surgery and occurs in response to peritoneal trauma. The pathogenesis is still unknown but includes an imbalance in fibrinolysis, collagen production and inflammatory mechanisms. Little is known about the role of macrophages during adhesion formation. In an experimental model, macrophage M2 marker expression was associated with reduced peritoneal adhesion formation and involved PPAR-γ-mediated arginase activity. Macrophage-specific PPAR-γ deficiency resulted in reduced arginase activity and aggravated adhesion formation. Pioglitazone, a PPAR-γ agonist, induced M2 polarization and reduced postoperative adhesion formation without compromising anastomotic healing in mice. Pioglitazone ameliorated postoperative adhesion formation without compromising intestinal wound healing. Therefore, perioperative PPAR-γ agonism might be a promising strategy for prevention of adhesion formation after abdominal surgery.

Practical Relativistic Bit Commitment

Bit commitment is a fundamental cryptographic primitive in which Alice wishes to commit a secret bit to Bob. Perfectly secure bit commitment between two mistrustful parties is impossible through an asynchronous exchange of quantum information. Perfect security is, however, possible when Alice and Bob each split into several agents exchanging classical information at times and locations suitably chosen to satisfy specific relativistic constraints. In this Letter we first revisit a previously proposed scheme [C. Crépeau et al., Lect. Notes Comput. Sci. 7073, 407 (2011)] that realizes bit commitment using only classical communication. We prove that the protocol is secure against quantum adversaries for a duration limited by the light-speed communication time between the locations of the agents. We then propose a novel multiround scheme based on finite-field arithmetic that extends the commitment time beyond this limit, and we prove its security against classical attacks. Finally, we present an implementation of these protocols using dedicated hardware and we demonstrate a 2 ms-long bit commitment over a distance of 131 km. By positioning the agents on antipodal points on the surface of Earth, the commitment time could possibly be extended to 212 ms.

The novel CGRP receptor antagonist BIBN4096BS alleviates a postoperative intestinal inflammation and prevents postoperative ileus

BACKGROUND

Abdominal surgery results in neuronal mediator release and subsequent acute intestinal hypomotility. This phase is followed by a longer lasting inflammatory phase resulting in postoperative ileus (POI). Calcitonin gene-related peptide (CGRP) has been shown to induce motility disturbances and in addition may be a candidate mediator to elicit neurogenic inflammation. We hypothesized that CGRP contributes to intestinal inflammation and POI.

METHODS

The effect of CGRP in POI was tested in mice treated with the highly specific CGRP receptor antagonist BIBN4096BS and in CGRP receptor-deficient (RAMP-1(-/-) ) mice. POI severity was analyzed by cytokine expression, muscular inflammation and gastrointestinal (GI) transit. Peritoneal and muscularis macrophages and mast cells were analyzed for CGRP receptor expression and functional response to CGRP stimulation.

KEY RESULTS

Intestinal manipulation (IM) resulted in CGRP release from myenteric nerves, and a concurrent increased interleukin (IL)-6 and IL-1β transcription and leukocyte infiltration in the muscularis externa and increased GI transit time. CGRP potentiates IM-induced cytokine transcription within the muscularis externa and peritoneal macrophages. BIBN4096BS reduced cytokine levels and leukocyte infiltration and normalized GI transit. RAMP1(-/-) mice showed a significantly reduced leukocyte influx. CGRP receptor was expressed in muscularis and peritoneal macrophages but not mast cells. CGRP mediated macrophage activation but failed to induce mast cell degranulation and cytokine expression.

CONCLUSIONS & INFERENCES

CGRP is immediately released during abdominal surgery and induces a neurogenic inflammation via activation of abdominal macrophages. BIBN4096BS prevented IM-induced inflammation and restored GI motility. These findings suggest that CGRP receptor antagonism could be instrumental in the prevention of POI.

Travelling fronts of the CO oxidation on Pd(111) with coverage-dependent diffusion

In this work, we study a surface reaction on Pd(111) crystals under ultra-high-vacuum conditions that can be modeled by two coupled reaction-diffusion equations. In the bistable regime, the reaction exhibits travelling fronts that can be observed experimentally using photo electron emission microscopy. The spatial profile of the fronts reveals a coverage-dependent diffusivity for one of the species. We propose a method to solve the nonlinear eigenvalue problem and compute the direction and the speed of the fronts based on a geometrical construction in phase-space. This method successfully captures the dependence of the speed on control parameters and diffusivities.

An experimental implementation of oblivious transfer in the noisy storage model

Cryptography's importance in our everyday lives continues to grow in our increasingly digital world. Oblivious transfer has long been a fundamental and important cryptographic primitive, as it is known that general two-party cryptographic tasks can be built from this basic building block. Here we show the experimental implementation of a 1-2 random oblivious transfer protocol by performing measurements on polarization-entangled photon pairs in a modified entangled quantum key distribution system, followed by all of the necessary classical postprocessing including one-way error correction. We successfully exchange a 1,366 bit random oblivious transfer string in ~3 min and include a full security analysis under the noisy storage model, accounting for all experimental error rates and finite size effects. This demonstrates the feasibility of using today's quantum technologies to implement secure two-party protocols.

[Immunomodulatory aspects in the development, prophylaxis and therapy for postoperative ileus]

Postoperative ileus (POI) is defined as a transient episode of impaired gastrointestinal motility after abdominal surgery, which prevents effective transit of intestinal contents or tolerance of oral intake. This frequent postoperative complication is accompanied by a considerable increase in morbidity and hospitalisation costs. The aetiology of POI is multifactorial. Besides a suppression of peristalsis by inhibitory neuronal signalling and administration of opioids, particularly in the prolonged form, immunological processes play an important role. After surgical trauma, resident macrophages of the muscularis externa (ME) are activated leading to the liberation of proinflammatory mediators and a spreading of the inflammation along the entire gastrointestinal tract. To date, no prophylaxis or evidence-based single approach exists to treat POI. Since none of the current treatment approaches (i.e., prokinetic drug treatment) has provided a benefit in randomised trials, immunoregulatory interventions appear to be more promising in POI prevention or treatment. The present contribution gives an overview of immunological mechanisms leading to POI focusing on current and future therapeutic and prophylactic approaches.

Experimental bit commitment based on quantum communication and special relativity

Bit commitment is a fundamental cryptographic primitive in which Bob wishes to commit a secret bit to Alice. Perfectly secure bit commitment between two mistrustful parties is impossible through asynchronous exchange of quantum information. Perfect security is however possible when Alice and Bob split into several agents exchanging classical and quantum information at times and locations suitably chosen to satisfy specific relativistic constraints. Here we report on an implementation of a bit commitment protocol using quantum communication and special relativity. Our protocol is based on [A. Kent, Phys. Rev. Lett. 109, 130501 (2012)] and has the advantage that it is practically feasible with arbitrary large separations between the agents in order to maximize the commitment time. By positioning agents in Geneva and Singapore, we obtain a commitment time of 15 ms. A security analysis considering experimental imperfections and finite statistics is presented.

The role of lymphoid tissue in the attenuation of the postoperative ileus

Standardized intestinal manipulation (IM) leads to local bowel wall inflammation subsequently spreading over the entire gastrointestinal tract. Previously, we demonstrated that this so-called gastrointestinal field effect (FE) is immune-mediated. The aim of this study was to investigate the role of secondary lymphoid organs [mesenteric lymph nodes (MLN), gut-associated lymphoid tissue (GALT)] in IM-mediated FE by employing mice with deficient secondary lymphoid organs (aly/aly, MLN ex) or by administration of 2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol (FTY720), an immunomodulating agent that inhibits emigration of lymphocytes out of lymphoid organs. Small bowel muscularis, and colonic muscularis from wild-type mice as control, from aly/aly mice, FTY720-treated mice (daily dose of 1.0 mg/kg mouse ip starting 3 days before surgical procedure), and wild-type mice that had undergone removal of mesenteric lymph nodes before IM (MLN ex mice) were obtained after selective IM of the jejunum or sham operation. FE was analyzed by measuring transit time of orally administered fluorescent dextran in the gastrointestinal tract [geometric center (GC) of fluorescent dextran], colonic transit time, infiltration of myeloperoxidase-positive cells, and circular smooth muscle contractility. Furthermore, mRNA levels of inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1α] were determined by Taqman-PCR. We observed a significantly reduced upregulation of proinflammatory cytokines (IL-6, TNF-α, MIP-1α) in colonic muscularis of MLN ex mice, aly/aly mice, and FTY720-treated mice compared with wild-type mice. Contractility of circular muscularis strips of the colon but not the jejunum was significantly improved in aly/aly mice and FTY720-treated wild-type mice. Additionally, inflammation of the colon determined by the number of myeloperoxidase-positive cells and colonic transit time were significantly improved in aly/aly mice, FTY720-treated wild-type mice, and in MLN ex mice. In summary, lack of secondary lymphoid organs (MLN + GALT) in aly/aly mice or administration of FTY720 abrogated FE after IM as opposed to wild-type mice. These data demonstrate that secondary lymphoid organs are involved in the propagation of FE and postoperative ileus. FTY720 indirectly affects FE by inhibiting migration of activated T cells from the jejunum and adjacent secondary lymphoid organs to the colon. These findings support the crucial role of the adaptive immune system in FE, most likely by a sphyngosine 1-phosphate-dependent mechanism.

Intestinal regeneration, residual function and immunological priming following rescue therapy after rat small bowel transplantation

Clinical evidence suggests that recurrent acute cellular rejection (ACR) may trigger chronic rejection and impair outcome after intestinal transplantation. To test this hypothesis and clarify underlying molecular mechanisms, orthotopic/allogenic intestinal transplantation was performed in rats. ACR was allowed to occur in a MHC-disparate combination (BN-LEW) and two rescue strategies (FK506monotherapy vs. FK506+infliximab) were tested against continuous immunosuppression without ACR, with observation for 7/14 and 21 days after transplantation. Both, FK506 and FK506+infliximab rescue therapy reversed ACR and resulted in improved histology and less cellular infiltration. Proinflammatory cytokines and chemotactic mediators in the muscle layer were significantly reduced in FK506 treated groups. Increased levels of CD4, FOXP3 and IL-17 (mRNA) were observed with infliximab. Contractile function improved significantly after FK506 rescue therapy, with a slight benefit from additional infliximab, but did not reach nontransplanted controls. Fibrosis onset was detected in both rescue groups by Sirius-Red staining with concomitant increase of the fibrogenic mediator VEGF. Recovery from ACR could be attained by both rescue therapy regimens, progressing steadily after initiation of immunosuppression. Reversal of ACR, however, resulted in early stage graft fibrosis. Additional infliximab treatment may enhance physiological recovery of the muscle layer and enteric nervous system independent of inflammatory reactions.

Perioperative infliximab application has marginal effects on ischemia-reperfusion injury in experimental small bowel transplantation in rats

PURPOSE

Ischemia-reperfusion injury leads to impaired smooth muscle function and inflammatory reactions after intestinal transplantation. In previous studies, infliximab has been shown to effectively protect allogenic intestinal grafts in the early phase after transplantation with resulting improved contractility. This study was designed to reveal protective effects of infliximab on ischemia-reperfusion injury in isogenic transplantation.

METHODS

Isogenic, orthotopic small bowel transplantation was performed in Lewis rats (3 h cold ischemia). Five groups were defined: non-transplanted animals with no treatment (group 1), isogenic transplanted animals with vehicle treatment (groups 2/3) or with infliximab treatment (5 mg/kg body weight intravenously, directly after reperfusion; groups 4/5). The treated animals were sacrificed after 3 (group 2/4) or 24 h (group 3/5). Histological and immunohistochemical analysis, TUNEL staining, real-time RT-PCR, and contractility measurements in a standard organ bath were used for determination of ischemia-reperfusion injury.

RESULTS

All transplanted animals showed reduced smooth muscle function, while no significant advantage of infliximab treatment was observed. Reduced infiltration of neutrophils was noted in the early phase in animals treated with infliximab. The structural integrity of the bowel and infiltration of ED1-positive monocytes and macrophages did not improve with infliximab treatment. At 3 h after reperfusion, mRNA expression of interleukin (IL)-6, TNF-α, IL-10, and iNOS and MCP-1 displayed increased activation in the infliximab group.

CONCLUSION

The protective effects of infliximab in the early phase after experimental small bowel transplantation seem to be unrelated to ischemia-reperfusion injury. The promising effects in allogenic transplantation indicate the need for further experiments with infliximab as complementary treatment under standard immunosuppressive therapy. Further experiments should focus on additional infliximab treatment in the setting of acute rejection.

Local quantum measurement and no-signaling imply quantum correlations

We show that, assuming that quantum mechanics holds locally, the finite speed of information is the principle that limits all possible correlations between distant parties to be quantum mechanical as well. Local quantum mechanics means that a Hilbert space is assigned to each party, and then all local positive-operator-valued measurements are (in principle) available; however, the joint system is not necessarily described by a Hilbert space. In particular, we do not assume the tensor product formalism between the joint systems. Our result shows that if any experiment would give nonlocal correlations beyond quantum mechanics, quantum theory would be invalidated even locally.

A technique for extending the precision and the range of temperature programmed desorption toward extremely low coverages

In this paper, an improvement of the temperature programmed desorption (TPD) technique is introduced, which facilitates fully automated sampling of TPD spectra with excellent reproducibility, especially useful for extremely low coverages. By averaging many sampled TPD spectra, the range of the TPD technique can be extended toward lower coverages, as well as the quality of the spectra can be improved. This allows for easy extraction of information about the adsorbate-surface bond. A state of the art TPD apparatus with a two chamber setup and a high quality quadrupole mass spectrometer was extended by automated components. These are an automated gas dosing system, ensuring precise dosing of gas, combined with a motor driven sample manipulation unit and a liquid nitrogen cryostat with automatic refilling. In addition all components were controlled by a computer. A large number of TPD cycles could be sampled without the need of interaction of an operator. Here, it is shown for up to more than 400 TPD cycles. This opens a wide range of new interesting applications for the TPD technique, especially in the limit of zero coverage. Here, basic experiments on well known adsorbate systems are shown to view the ability and limit of this approach.

Reaction hysteresis of the CO + O --> CO2 reaction on palladium(111)

Rate measurements of the reaction CO + O --> CO(2) on palladium(111) single crystal surfaces have been performed by means of mass spectroscopy under ultrahigh vacuum conditions. The total flux Phi of the impinging reactants CO and O(2) was held constant at 1 ML s(-1), whereas its CO fraction Y was varied between 0 (pure O(2)) and 1 (pure CO). The measurements have been performed for surface temperatures between 370 and 510 K and with a wide range of sampling times, evaluating the system parameter range for bistable behavior. Long-time measurements lasting several days proved the bistable behavior to result from two stable states rather than from slow processes not visible on usual experimental time scales. Pulselike modulations of the feed gas composition revealed the mechanisms confining the experimentally observed bistable range: the high CO fraction border of the bistability is given by the equistability condition of both states, whereas the other border is found to be associated with a saddle-node bifurcation in the corresponding system of reaction diffusion equations.

Resident macrophages are involved in intestinal transplantation-associated inflammation and motoric dysfunction of the graft muscularis

Gut manipulation and ischemia/reperfusion evoke an inflammatory response within the intestinal muscularis that contributes to dysmotility. We hypothesize that resident macrophages play a key role in initiating the inflammatory cascade. Isogenic small bowel transplantation was performed in Lewis rats. The impact of recovery of organs on muscularis inflammation was investigated by comparing cold whole-body perfusion after versus prior to recovery. The role of macrophages was investigated by transplantation of macrophage-depleted gut. Leukocytes were counted using muscularis whole mounts. Mediator expression was determined by real-time RT-PCR. Contractility was assessed in a standard organ bath. Both organ recovery and ischemia/reperfusion induced leukocyte recruitment and a significant upregulation in IL-6, MCP-1, ICAM-1 and iNOS mRNAs. Although organ recovery in cold ischemia prevented early gene expression, peak expression was not changed by modification of the recovery technique. Compared to controls, transplanted animals showed a 65% decrease in smooth muscle contractility. In contrast, transplanted macrophage-depleted isografts exhibited significant less leukocyte infiltration and only a 19% decrease in contractile activity. In summary, intestinal manipulation during recovery of organs initiates a functionally relevant inflammatory response within the intestinal muscularis that is massively intensified by the ischemia reperfusion injury. Resident muscularis macrophages participate in initiating this inflammatory response.

The role of dendritic cells in the gastrointestinal field effect

INTRODUCTION

Intestinal manipulation leads to local bowel wall inflammation that subsequently spreads over the entire gastrointestinal tract. Previously, this gastrointestinal field effect had been demonstrated by us in a rodent model. We herein postulated an immunologic mechanism mediated by activated leukocytes. The aim of this study was to investigate the activation, maturation and migration of dendritic cells (DC) of the intestinal smooth muscle following surgical trauma and i.p. lipopolysaccharide challenge.

METHODS

Mice underwent standardized intestinal manipulation or iP LPS administration and tissues (intestinal muscularis, Peyer's patches, mesenteric lymph nodes, and spleen) were obtained at various times after manipulation. DC were isolated by tissue digestion and separated by CD11c-iMAG. The harvested DC were analyzed by FACS. The activation pattern of DC was analyzed by polymerase chain reaction.

RESULTS

We found a significant increase in DC within the intestinal muscularis, the Peyer's patches and the mesenteric lymph nodes at 6 and 12 hours following intestinal manipulation and injection of LPS. There was an upregulation of the costimulatory molecules major histocompatibility complex II, CD40, CD80, CD86, and CD205 in the DC after intestinal manipulation. CCR-2, CCR-5, CCR-7, CCL-19, and interleukin-12a were upregulated in a time- and tissue-dependent manner.

CONCLUSION

Intestinal manipulation or LPS challenge induced a recruitment of DC into the muscularis externa and mesenteric lymph nodes combined with an upregulation of costimulatory immunocompetent molecules and migratory surface markers in DCs. These findings demonstrate a precondition for an immunologic response and a possible immunologically mediated gastrointestinal field effect.

IV tissue plasminogen activator use in acute stroke: experience from a statewide registry

OBJECTIVE

To assess the use of IV recombinant tissue plasminogen activator (rt-PA) in a statewide hospital-based stroke registry and to identify factors associated with its use among eligible patients.

METHODS

A modified stratified sampling scheme was used to obtain a representative sample of 16 hospitals. Prospective case ascertainment and data collection were used to identify all acute stroke admissions over a 6-month period. Subjects eligible for IV rt-PA were defined as those who arrived within 3 hours of onset, who had no evidence of hemorrhage on initial brain image, and who had no physician-documented reasons for non-treatment with IV rt-PA. Multivariate logistic regression was used to identify factors associated with IV rt-PA use.

RESULTS

Of 2,566 stroke admissions, 330 (12.9%) met the eligibility criteria for rt-PA treatment, and of these 43 (13%) received IV rt-PA treatment. Among 2,236 admissions excluded from consideration, 21% had evidence of hemorrhage on initial imaging, 35% had unknown stroke onset times, 38% had an onset to arrival time >3 hours, and 6% had physician documented contraindications. Among eligible patients, being male, use of emergency medical services, and rapid presentation were associated with increased IV rt-PA use.

CONCLUSIONS

Treatment with IV rt-PA was underutilized in this hospital-based stroke registry. The primary reason for nontreatment was delayed presentation. Reducing prehospital and in-hospital response times would help increase IV rt-PA use, as would greater emergency medical services use. Improving the documentation of onset times would help clarify the underlying causes of delayed presentation.

Noise-induced spatiotemporal patterns in a bistable reaction-diffusion system: photoelectron emission microscopy experiments and modeling of the oxidation reaction on Ir(111)

We use photoelectron emission microscopy (PEEM) measurements to study the spatiotemporal patterns obtained for the CO oxidation reaction on Ir(111) as a function of the noise strength we superpose on the CO and the oxygen fractions of the constant total reactant gas flux. The investigations are focused on the bistable regime this reaction displays including its monostable vicinity. Simultaneously we analyze numerically the underlying reaction-diffusion (RD) equations in two spatial dimensions. For intrinsic and/or small strength of the external noise we find transitions from the locally stable to the globally stable branch via slow nucleation and growth of islands of the globally stable state: oxygen or CO, respectively. With increasing noise strength the number of islands as well as their growth rate increases. These phenomena are very well reproduced by numerical calculations of the RD model. For sufficiently large noise strength we observe bursts from CO rich to oxygen rich and back as well as switching between the two states. While such phenomena are also obtained from the model calculations, their experimentally observed spatial scales were not satisfactorily reproduced using the same approach as for the lower noise strengths.

Spatiotemporal patterns of external noise-induced transitions in a bistable reaction-diffusion system: photoelectron emission microscopy experiments and modeling

The rate of CO oxidation on Ir(111) surfaces exhibits bistability at T=500 K in a range of the CO fraction Y in the CO+O reactant gas flux. Measured CO2 rates as a function of the noise strength imposed on Y are well reproduced by parameter-free modeling. We present photoelectron emission microscopy measurements and 2D calculations of the spatiotemporal patterns of CO- and O-rich domains. The role of combined multiplicative and additive noise on Y for CO and O domain wall motion and island nucleation-growth-coalescence processes is analyzed.

Bedeutung der Stimmkonstitution f�r die Entstehung von Berufsdysphonien

Occupational voice disorders have been increasing for years. The aim of this study was to examine whether a constitutionally weak voice should be regarded as a risk factor for developing such voice disorders. In a prospective study, 15 female teacher students with a normal vocal constitution were compared with 18 students with constitutionally weak voices during teaching practice. There was a significant difference in the mean fundamental frequency of both groups after teaching for 30 min. Students with constitutionally weak voices tended to have increased values. Taking into consideration the physiological aspects of an increasing fundamental frequency as a sign of vocal fatigue, a constitutionally weak voice has to be regarded as a potential risk factor for developing a voice disorder in vocally intensive occupations. To prevent future vocal problems by appropriate prophylactic intervention (i.e. voice therapy, introduction to vocal hygiene), a phoniatric examination of vocal constitution and endurance is recommended at the beginning of a voice dependent professional career.

External noise imposed on the reaction-diffusion system CO+O2-->CO2 on Ir(111) surfaces: experiment and theory

We study experimentally and theoretically the influence of noise on the fractions of CO and oxygen in the constant gas flow directed at an Ir(111) surface during CO oxidation. Depending on the noise strength and the fraction Y of CO we observe in the deterministically bistable region a large variety of different types of behavior. These include bistable behavior for small noise intensities, transitions from the upper to the lower branch of the bistable loop and vice versa, island nucleation and growth and noise-induced switching. Near the boundary of the bistable region and in the presence of noise the transition between the two branches takes place via very slow domain wall motion with time scales of the order of 10(4)-10(5) s. The experiments were carried out in an UHV system for which the mass flow could be controlled very precisely. The modeling was using the reaction-diffusion system underlying the reaction studied for which all the kinetic coefficients are known rather precisely. Our numerical analysis was performed for one and two spatial dimensions showing qualitatively similar behavior. The comparison between the experimental results and the modeling shows semiquantitative to quantitative agreement.