Non-surgical external jugular vein catheterization using an ear vein access in piglets.

The objective of this study was to investigate the feasibility of external jugular vein catheterization through an ear vein in piglets. Forty-six sevoflurane-midazolam anaesthetized piglets were included. External jugular vein catheterization was conducted through the ear vein using the Seldinger technique. Part 1 (n = 27): optimal puncture site was based on the deltoid tuberosity as a landmark to reach the external jugular vein. The final position of the catheter was verified in 25 piglets using computer tomography. Catheterization time was recorded and patency of the catheter assessed by repeated blood sampling for up to 4 h. Part 2 (n = 19): ear vein catheterization was without taking into account any landmarks. Functionality for blood sampling was evaluated as described in part 1. Catheter advancement was possible in 25/27 and 18/19 piglets in parts 1 and 2, respectively. Median (range) time required for successful catheterization was 1.95 (1-10) min (n = 38). The deltoid tuberosity was a good landmark to reach the external jugular vein. But blood sampling was also possible through catheters ending slightly cranial to the external jugular vein. Despite successful catheter advancement, blood sampling was not possible from one catheter in each part of the study (total: two piglets). One of these catheters presented luminal damage, while the other one presented as normal after being removed from the animal. Summarizing, central vein catheterization through the ear vein was feasible in 93.5% and repeated blood sampling was possible in 89.1% of the piglets (n = 46).

[The importance of a veterinary anaesthetist and pain treatment according to dog and cat owners]. / Bedeutung einer Veterinäranästhesistin oder eines Veterinäranästhesisten und einer optimalen Schmerztherapie aus Sicht von Hunde- und Katzenbesitzerinnen und -besitzer.

INTRODUCTION: In Switzerland, compared to the United Kingdom or the United States of America, fewer veterinary anaesthetists are employed in private practice, which raises the question about the reason. The present survey aimed at investigating the awareness of pet owners concerning the specialization of veterinary anaesthesia and the value they attribute to such a specialist. Also, estimation of pain in dogs and cats and the importance of its treatment from the point of view of the pet owners was analysed. Furthermore, the necessity of veterinary anaesthetists in private practice and the influencing factors were investigated. The survey was created on LimeSurvey, an online tool for questionnaires and sent to dog and cat owners of the small animal clinic of the University Hospital of Zurich. 317 fully completed questionnaires were evaluated. In general, pet owners appreciated the specialization of veterinary anaesthesiology. Great importance was attributed to the supervision of anaesthesia and analgesic therapy by a specialist. A preliminary talk with an anaesthetist would be appreciated. Owners would be willing to cover additional costs for a specialized anaesthetist, if recommended by the private veterinarian, and to bring their animal to the University Hospital, in case of an increased anaesthetic risk.

INTRODUCTION: En Suisse, les vétérinaires anesthésistes sont moins nombreux à exercer en cabinet privé qu'au Royaume-Uni ou aux États-Unis. La question se pose dès lors de savoir pourquoi il en est ainsi. Une enquête a analysé les connaissances des propriétaires d'animaux de compagnie sur la spécialisation de l'anesthésiologie vétérinaire et l'importance qu'ils accordent à un spécialiste en la matière. L'importance de la thérapie analgésique chez les chiens ou les chats a également été évaluée. En outre, le besoin en vétérinaires anesthésistes en pratique privée et les facteurs qui l'influencent ont été examinés. L'enquête a utilisé l'outil de questionnaire Lime-Survey et a été envoyée aux propriétaires de chiens et de chats de la Clinique des petits animaux de l'Université de Zürich. 317 questionnaires complétés ont été évalués. Les propriétaires d'animaux apprécient la spécialisation en l'anesthésiologie vétérinaire. Le vétérinaire anesthésiste est considéré comme très important dans les mesures anes-thésiques et la thérapie analgésique. Une consultation anesthésique préalable est souhaitée. Les propriétaires seraient disposés à prendre en charge les coûts supplémentaires de ce service ou, sur recommandation du vétérinaire privé, à amener leur animal à la Clinique pour petits animaux de l'Université de Zürich en cas de risque anesthésique accru.

Revealing latent pole and zone line information in atom probe detector maps using crystallographically correlated metrics.

Poles and zone lines observed within atom probe field evaporation images are useful for a range of atom probe crystallography studies, including calibration of the reconstruction and crystallographic characterisation of microstructural features such as grain boundaries. However, this information is not always readily apparent. Techniques for plotting crystallographically correlated metrics contained within atom probe data to enhance pole and zone line contrast across the detector space are developed. This includes consideration of the electric field, molecular ions, lattice structure retained within the reconstruction, specific elemental species, the number of pulses between detection events, and the lateral distance between sequential detection events. These approaches are then applied to experimental atom probe tomography datasets on technically pure Al, nanocrystalline Al, highly doped Si, and additively manufactured Inconel 738, Haynes 282, and Ti-6Al-4V. The results facilitate the extension of atom probe crystallography studies to a broader range of crystalline datasets where crystallographic information is not readily apparent from existing methods, as well as a deeper understanding of field evaporation behaviour during an atom probe experiment.

Correlative study of lattice imperfections in long-range ordered, nano-scale domains in a Fe-Co-Mo alloy.

Recent advancements in data mining methods in atom probe microscopy have enabled new quantitative chemical and microstructural characterization beyond the standard three-dimensional reconstruction. For example, spatial distribution maps have been developed to enable visualisation of the local lattice occupation of a selected region of interest. However, the precision of such studies yet remains unknown as correlation with complementary methods would be required. Therefore, a correlative study of atom probe microscopy, neutron diffraction and microstructural modelling of long-range ordered, nano-scale domains in a well-researched Fe-Co-Mo Maraging-type steel is presented here. Its microstructure consists of Mo-enriched µ-phase (Fe,Co)7Mo6 particles embedded into a body-centred cubic FeCo matrix. Previous research has shown that under slow cooling conditions, this matrix partially decomposes into nano-scale B2 long-range ordered domains surrounded by disordered regions, resulting in reduced toughness in potential cutting applications. Usually, a long-range order parameter S referring to ideal B2 long-range order is assumed within such domains according to neutron diffraction. However, atom probe microscopy and modelling results presented in the current study indicate lattice imperfections with a partial substitution of atoms on the Fe- and Co-sublattices. After considering preferential retention effects during the atom probe experiment, a model unit cell is presented to define the observed imperfect B2 long-range order as pseudo-D03 long-range order, and the potential impact on the materials properties is discussed.

Non-destructive analysis on nano-textured surface of the vertical LED for light enhancement.

In this work, the nano-textured surface of a GaN-based vertical light emitting diode (VLED) is characterized using a unified framework of non-destructive techniques (NDT) incorporating scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy, Photoluminescence (PL), and X-ray diffraction (XRD) to optimize the light output efficiency. The surface roughness of ∼300 nm is revealed by AFM. Compressive stress-state of 0.667 GPa in the GaN surface is indicated by the E2(high) and A1(LO) phonon peak values at 569 cm-1 and 736 cm-1, respectively, in Raman spectrum and the wavelength at 442 nm rather 450 nm in PL spectrum. Without damaging the LED, surface analysis by NDT helps to advance the understanding of the optimized angular light redistribution subject to the high-roughness surface and the negative impacts of the stress induced at the top GaN layer, which leads to the optical efficiency degradation of the VLED. Furthermore, the impact of texturing on underneath n-GaN and MQWs layers is investigated via SEM-based transmission Kikuchi diffraction (TKD) and aberration-corrected scanning transmission electron microscopy (AC-STEM) and revealed a smooth surface morphology and good crystalline quality, indicating that the etch-induced damage by texture engineering does not impair the active region of the VLED. Accordingly, prospective optimizations are suggested in the context of surface engineering for light enhancement in VLEDs.

Effects of moderate and severe arterial hypotension on intracerebral perfusion and brain tissue oxygenation in piglets.

BACKGROUND: Hypotension is common in anaesthetised children, and its impact on cerebral oxygenation is unknown. The goal of the present study was to investigate the effects of moderate systemic arterial hypotension (mHT) and severe hypotension (sHT) on cerebral perfusion and brain tissue oxygenation in piglets. METHODS: Twenty-seven anaesthetised piglets were randomly allocated to a control group, mHT group, or sHT group. Cerebral monitoring comprised a tissue oxygen partial pressure ( [Formula: see text] ) and laser Doppler (LD) perfusion probe advanced into the brain tissue, and a near-infrared spectroscopy sensor placed over the skin measuring regional oxygen saturation (rSO2). Arterial hypotension was induced by blood withdrawal and i.v. nitroprusside infusion [target MAP: 35-38 (mHT) and 27-30 (sHT) mm Hg]. Data were analysed at baseline, and every 20 min during and after treatment. RESULTS: Compared with control, [Formula: see text] decreased equally with mHT and sHT [mean (SD) after 60 min: control: 17.1 (6.4); mHT: 6.4 (3.6); sHT: 7.2 (4.3) mm Hg]. No differences between groups were detected for rSO2 and LD during treatment. However, in the sHT group, rSO2 increased after restoring normotension [from 49.3 (9.5) to 58.9 (8.9)% Post60]. sHT was associated with an increase in blood lactate [from 1.5 (0.4) to 2.4 (0.9) mmol L-1], and a decrease in bicarbonate [28 (2.4) to 25.8 (2.6) mmol L-1] and base excess [4.7 (1.9) to 2.0 (2.7) mmol L-1] between baseline and 60 min after the start of the experiment. CONCLUSIONS: Induction of mHT and sHT by hypovolaemia and nitroprusside infusion caused alterations in brain tissue oxygenation in a piglet model, but without detectable changes in brain tissue perfusion and regional oxygen saturation.

TDDFT Study of the Optical Excitation of Nucleic Acid Bases-C60 Complexes.

The potential of C60 as a nucleic acid base (NAB) optical sensor is theoretically explored. We investigate the adsorption of four NABs, namely, adenine, cytosine, guanine, and thymine, on C60 in the gas phase. For the optimal NAB@C60 adsorption configurations, obtained using a dispersion-corrected density functional, we calculate the vis-near-ultraviolet optical response using time-dependent density functional theory. While the isolated C60 and NAB molecules do not exhibit visible optical excitation, we find that C60/NAB conjugation gives rise to distinct spectral features in the visible range. These results suggest that C60 conjugation can be applied for photodetection of individual NABs.

Near-Perfect Spin Filtering and Negative Differential Resistance in an Fe(II)S Complex.

Density functional theory and nonequilibrium Green's function calculations have been used to explore spin-resolved transport through the high-spin state of an iron(II)sulfur single molecular magnet. Our results show that this molecule exhibits near-perfect spin filtering, where the spin-filtering efficiency is above 99%, as well as significant negative differential resistance centered at a low bias voltage. The rise in the spin-up conductivity up to the bias voltage of 0.4 V is dominated by a conductive lowest unoccupied molecular orbital, and this is accompanied by a slight increase in the magnetic moment of the Fe atom. The subsequent drop in the spin-up conductivity is because the conductive channel moves to the highest occupied molecular orbital, which has a lower conductance contribution. This is accompanied by a drop in the magnetic moment of the Fe atom. These two exceptional properties, and the fact that the onset of negative differential resistance occurs at low bias voltage, suggests the potential of the molecule in nanoelectronic and nanospintronic applications.

Intrinsic Ferromagnetism in the Diluted Magnetic Semiconductor Co:TiO_{2}.

Here we present a study of magnetism in Co_{0.05}Ti_{0.95}O_{2-δ} anatase films grown by pulsed laser deposition under a variety of oxygen partial pressures and deposition rates. Energy-dispersive spectrometry and transmission electron microscopy analyses indicate that a high deposition rate leads to a homogeneous microstructure, while a very low rate or postannealing results in cobalt clustering. Depth resolved low-energy muon spin rotation experiments show that films grown at a low oxygen partial pressure (≈10^{-6} torr) with a uniform structure are fully magnetic, indicating intrinsic ferromagnetism. First principles calculations identify the beneficial role of low oxygen partial pressure in the realization of uniform carrier-mediated ferromagnetism. This work demonstrates that Co:TiO_{2} is an intrinsic diluted magnetic semiconductor.

Endohedral metallofullerenes, M@C60 (M = Ca, Na, Sr): selective adsorption and sensing of open-shell NOx gases.

Based on density-functional theory and non-equilibrium Green's function calculations, we demonstrate that endohedral metallofullerenes (EMFs) are reactive to open-shell gases, and therefore have the potential application as selective open-shell gas sensors. The adsorption of eight gas species (CO, H2O, H2S, NO2, NO, SO2, O2 and NH3) on three EMFs (M@C60, M = Ca, Na and Sr) shows that the adsorption energies of the EMFs towards NO2 and NO are significantly higher than the closed-shell species. Moreover, the high selectivity appears relatively insensitive to the inserted metal atoms. The calculated current-voltage characteristics of gold-M@C60-gold structures (M = Ca, Na) show that the adsorption of NO2 leads to significant change in conductivity, suggesting a potential application as an EMF gas resistive sensing device.

Large spin-filtering effect in Ti-doped defective zigzag graphene nanoribbon.

Through first-principles calculations using the nonequilibrium Green's function formalism together with density functional theory, we study the conductance of double-vacancy zigzag graphene nanoribbons doped with four transition metal atoms Ti, V, Cr and Fe. We show that Ti doping induces large spin-filtering with an efficiency in excess of 90% for bias voltages below 0.5 V, while the other metal adatoms do not induce large spin filtering. This is despite the fact that the Ti dopant possesses small spin moment, while large moments reside on V, Cr and Fe dopants. Our analysis shows that the suppression of transmission in the spin-down channel in the Ti-doped graphene nanoribbon, thus the large spin filtering efficiency, is due to transmission anti-resonance arising from destructive quantum interference. These findings suggest that the decoration of graphene with titanium, and possibly other transition metals, can act as effective spin filters for nanospintronic applications.

Communication: Electrical rectification of C59N: The role of anchoring and doping sites.

Based on the nonequilibrium Green's function formalism and density-functional theory, we investigate the onset of electrical rectification in a single C59N molecule in conjunction with gold electrodes. Our calculations reveal that rectification is dependent upon the anchoring of the Au atom on C59N; when the Au electrode is singly bonded to a C atom (labeled here as A), the system does not exhibit rectification, whereas when the electrode is connected to the C-C bridge site between two hexagonal rings (labeled here as B), transmission asymmetry is observed, where the rectification ratio reaches up to 2.62 at ±1 V depending on the N doping site relative to the anchoring site. Our analysis of the transmission mechanism shows that N doping of the B configuration causes rectification because more transmission channels are available for transmission in the B configuration than in the A configuration.

Enhanced oscillatory rectification and negative differential resistance in pentamantane diamondoid-cumulene systems.

We propose a new functionality for diamondoids in nanoelectronics. Based on the nonequilibrium Green's function formalism and density functional theory, we reveal that when attached to gold electrodes, the pentamantane-cumulene molecular junction exhibits large and oscillatory rectification and negative differential resistance (NDR) - depending on the number of carbon atoms in cumulene (Cn). When n is odd rectification is greatly enhanced where the rectification ratio can reach ∼180 and a large negative differential resistance peak current of ∼3 µA. This oscillatory behavior is well rationalised in terms of the occupancy of the carbon 2p states in Cn. Interestingly, different layers of C atoms in the pentamantane molecule have different contributions to transmission. The first and third layers of C atoms in pentamantane have a slight contribution to rectification, and the fifth and sixth layers have a stronger contribution to both rectification and NDR. Thus, our results suggest potential avenues for controlling their functions by chemically manipulating various parts of the diamondoid molecule, thus extending the applications of diamondoids in nanoscale integrated circuits.

[Pneumothorax during right-sided nephrectomy in a heifer]. / Pneumothorax als Komplikation einer rechtsseitigen Nephrektomie bei einem Jungrind.

A 250-kg heifer had signs of colic attributable to urolithiasis of the right kidney. Medical treatment did not result in resolution of clinical signs, and nephrectomy was carried out. The surgery was started with the heifer standing, and the 13th rib was resected. However, during blunt dissection of the kidney, air suddenly entered the pleural space and the heifer had acute severe dyspnoea. The hole in the pleural cavity was sutured and a chest drain was placed. Inhalation anaesthesia was then induced and nephrectomy could be completed without further complications. The heifer was discharged 11 days postoperatively, and was healthy and had been integrated into the herd 12 months after surgery. Pneumothorax must be considered a possible complication of rib resection in right-sided nephrectomy in cattle.

Fentanyl bolus induces muscle tremors in sevoflurane-anaesthetized piglets.

Intravenous fentanyl (10 mcg/kg) or saline (control) was randomly administered to 10 healthy sevoflurane-mono-anaesthetized piglets. Trembling was assessed by two blinded observers using a visual analogue scale (VAS) and a simple ordinal scale at baseline and 5 min (T5) after drug administration. If no trembling was observed at that time point, the opposite treatment was administered and piglets were re-evaluated after another 5 min (T10). Four out of five piglets showed trembling after fentanyl (T5), while none given saline showed any trembling. With fentanyl the VAS scores were significantly higher at T5 compared either with baseline or with the control treatment. Control animals received fentanyl after the 5 min evaluation and all piglets showed clear trembling afterwards. The median time after fentanyl administration until first muscle tremors was 51 (20-840) s. In summary, nine out of 10 sevoflurane-anaesthetized piglets showed muscle tremors after intravenous fentanyl. Tremors subsided over time and no specific treatment was necessary.

High On/Off Conductance Switching Ratio via H-Tautomerization in Quinone.

Through first-principles electron transport simulations using the nonequilibrium Green's function formalism together with density functional theory, we show that, upon H-tautomerization, a simple derivative of quinone can act as a molecular switch with high ON/OFF ratio, up to 70 at low bias voltage. This switching behavior is explained by the quantum interference effect, where the positional change of hydrogen atoms causes the energies of the transmission channels to overlap. Our results suggest that this molecule could have potential applications as an effective switching device.

Effects of 10% hydroxyethyl starch (HES 200/0.5) solution in intraoperative fluid therapy management of horses undergoing elective surgical procedures.

The aim of the present study was to investigate the effect of pentastarch on colloid osmotic pressure (COP) and cardiopulmonary function during and up to 24 h after anaesthesia in horses. Twenty-five systemically healthy horses were anaesthetised using isoflurane-medetomidine balanced anaesthesia. Twelve were assigned to treatment with hydroxyethyl starch (HES) (H group) and 13 to no HES (NH group). In the H group, 6 mL/kg of pentastarch 10% HES (200/0.5) was infused over 1 h starting 30 min after induction of anaesthesia. Horses of the NH group received an equal amount of lactated Ringer's solution (LRS). COP and blood biochemical, cardiopulmonary and anaesthesia-related variables were measured at different time points before and after treatment. Pentastarch was effective in correcting the decrease in COP observed with LRS administration. No differences between treatments were detected for blood glucose, lactate, total proteins and electrolytes. Packed cell volume was lower with the H group immediately after finishing HES-administration and for an additional 30 min. In all horses, all blood biochemical variables other than lactate returned to normal after 12 h. No clinically relevant differences between treatments were detected for cardiopulmonary variables, although 23.1% of the NH-horses needed rescue-HES to maintain cardiovascular function, while none of the H-horses needed additional colloids. Overall, 6 mL/kg HES (200/0.5) was found to be effective in maintaining COP during anaesthesia in systemically healthy horses. Intermediate and long-term effects were below the limit of detection. The potentially beneficial effects on cardiovascular function need further investigation, especially in critically ill horses.

Bistable Magnetism and Potential for Voltage-Induced Spin Crossover in Dilute Magnetic Ferroelectrics.

A first-principles investigation into the magnetic ferroelectric PbTi(1-x)Co(x)O(3) has revealed a bi-stable magnetic system with strong spin-lattice coupling. The local distortions induced by the low-spin to high-spin crossover are ferroelectric in nature, and are characterized by the displacement of the dopant ion with respect to the surrounding O(6) octahedral cage. We demonstrate how this spin-lattice effect could mediate magnetoelectric coupling and possible electric field induced spin-crossover, indicating a promising route to voltage manipulation of isolated spins in a solid-state system.

Quantitative chemical-structure evaluation using atom probe tomography: Short-range order analysis of Fe-Al.

Short-range-order (SRO) has been quantitatively evaluated in an Fe-18Al (at%) alloy using atom probe tomography (APT) data and by calculation of the generalised multicomponent short-range order (GM-SRO) parameters, which have been determined by shell-based analysis of the three-dimensional atomic positions. The accuracy of this method with respect to limited detector efficiency and spatial resolution is tested against simulated D03 ordered data. Whilst there is minimal adverse effect from limited atom probe instrument detector efficiency, the combination of this with imperfect spatial resolution has the effect of making the data appear more randomised. The value of lattice rectification of the experimental APT data prior to GM-SRO analysis is demonstrated through improved information sensitivity.

New approaches to nanoparticle sample fabrication for atom probe tomography.

Due to their unique properties, nano-sized materials such as nanoparticles and nanowires are receiving considerable attention. However, little data is available about their chemical makeup at the atomic scale, especially in three dimensions (3D). Atom probe tomography is able to answer many important questions about these materials if the challenge of producing a suitable sample can be overcome. In order to achieve this, the nanomaterial needs to be positioned within the end of a tip and fixed there so the sample possesses sufficient structural integrity for analysis. Here we provide a detailed description of various techniques that have been used to position nanoparticles on substrates for atom probe analysis. In some of the approaches, this is combined with deposition techniques to incorporate the particles into a solid matrix, and focused ion beam processing is then used to fabricate atom probe samples from this composite. Using these approaches, data has been achieved from 10-20 nm core-shell nanoparticles that were extracted directly from suspension (i.e. with no chemical modification) with a resolution of better than ± 1 nm.