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Objective: Disturbed wound healing is a significant problem in patients after cardiac surgery. Problems with deep sternal wound healing are rare, but can be quite difficult to treat. Furthermore, the therapy is highly expensive and consumes many of the patient’s personal resources. Another major obstacle in this patient group is reinfection after secondary wound closure. We examined how to prevent early reinfection through the use of growth factors in combination with local antibiotics. Methods: Our study included 232 patients with a deep sternal wound healing problem. After initial vacuum therapy, we planned secondary wound closure. During wound closure, we used only platelet-rich fibrin in a PRF group (109 patients). In another group (123 patients), we covered the wounds intraoperatively with a combination of PRF and local antibiotics (PRF CoDelivery). All patients were observed for 30 days for signs of early surgical site infection. Results: After 30 days, 22 patients (20.2%) in the PRF group showed a persistent problem with wound healing with or without reinfection. In contrast, only 12 patients (9.8%) in the PRF CoDelivery group had this problem (p=0.023 PRF vs. PRF CoDelivery). Conclusion: The combination of growth factors and antibiotics was associated with a significantly reduced incidence of early reinfection and thus can be expected to have a positive impact on wound healing in complicated scenarios. Furthermore, the combination of PRF and local antibiotics was easy to use. Further studies are needed to verify these initial findings.

Background Conventional stented valves (CV) remain gold standard for aortic valve disease. Bovine prostheses have been improved and rapid deployment valves (RDV) have arrived in the recent decade. We compare clinical and hemodynamic short-term outcome of six bovine valves. Methods We retrospectively evaluated 829 consecutive patients (all-comers) receiving bovine aortic valve replacement (AVR). Four CV from different manufacturers (Mitroflow, Crown, Perimount, Trifecta) and two RDV (Perceval, Intuity) were compared in terms of pre-, intra-, and postprocedural data. A risk model for mortality was created. Results All valves reduced gradients. From 23 mm, all CV showed acceptable gradients. Twenty-one millimeter Mitroflow/Perceval and 19 mm Crown showed above-average gradients. As baseline data differed, we performed propensity matching between aggregated isolated CV and RDV groups. Cardiopulmonary bypass (CPB), clamp, and surgery times were shorter with RDV (87.4 ± 34.0 min vs 111.0 ± 34.2, 54.3 ± 21.1 vs 74.9 ± 20.4, 155.2 ± 42.9 vs 178.0 ± 46.8, p Conclusion Isolated bovine AVR has low mortality. Valves ≥ 23 mm show comparable gradients while the valve model matters

Background Atherosclerosis, hypertension, age, and fibrillopathies are well-known risk factors for the development of aortic aneurysm. We discovered that a significant proportion of our patients were previously on chemotherapy treatment or long-term treatment with cytostatic agents or immunosuppressive drugs. Thus, we examined this phenomenon. Methods A total of 224 patients with thoracic aorta aneurysm were retrospectively analyzed after aortic surgery from 2006 to 2016. Seventy-three patients received aortic wrapping and 151 patients underwent aortic replacement of which 89 had a valve-carrying conduit and 62 a supracoronary ascending replacement. Aortic morphology was assessed by means of compute tomography scan before and after surgery. Demographic data, risk profile, and postoperative complications were collected. Short- and long-term survival analysis was performed. Statistical analysis was performed with SPSS 19.0. Results Eighty-eight of 224 patients undergoing aortic surgery because of aortic aneurysm had previously or currently been treated with immunosuppressive agents. Dilatation of the ascending aorta was more pronounced in patients without such therapy. Demographic profile, intraoperative, as well as short- and long-term postoperative results did not differ significantly between both groups. Conclusion The potential effect of immunosuppressant and cytostatic therapies on the development of an aortic aneurysm needs further study. Because of the astoundingly high proportion of these patients being found in an unselected aortic aneurysm cohort with immunosuppressive therapy in the past should be monitored for potential development of aortic aneurysm. If it occurs and requires treatment these patients can fortunately be operated upon with the same short- and long-term outcome than patients without such previous therapy.

OBJECTIVES Although indications for the MitraClip are becoming increasingly liberal, the number of patients requiring valve surgery after an insufficient outcome of the procedure is growing. Referral to surgery is, however, frequently delayed. During this time, the patients often deteriorate. We retrospectively analysed patients before MitraClip implantation and after mitral valve surgery. METHODS A total of 49 patients who received a mitral valve replacement (average 8 ± 12 months after MitraClip implantation) were assessed. Of these, 53% had 2–4 clips inserted. The mean age was 73 years, and the mean log EuroSCORE was 20.79 ± 14.42%. Echocardiographic data obtained prior to MitraClip implantation and preoperatively, 10 days and 6 and 12 months after cardiac surgery were reviewed. Survival analysis, risk profile and postoperative complications were analysed. RESULTS The 30-day and 1-year mortality was 26.5% and 59.2%, respectively. Prior to MitraClip implantation, 42.8% of patients had mild tricuspid insufficiency and 6.1% had moderate tricuspid insufficiency. Prior to surgery, 26.5% showed mild, 32.7% moderate and 38.8% severe tricuspid insufficiency (P CONCLUSIONS A subgroup of patients does not benefit from a MitraClip and shows progressive deterioration in cardiac function, making valve replacement under difficult circumstances inevitable. The earlier these patients are operated on, the better it is. It can be assumed that some patients would be better off with primary surgery, especially if mitral reconstruction is then still feasible. Therefore, the indications for MitraClip implantation should be carefully considered and caution should be exercised during monitoring.

Objectives The invention of new surgical procedures requires testing at different stages including animal models. To facilitate this process, we have developed a computer-controlled extracorporeal circulation system for testing of an explanted porcine heart simulating a variety of physiological parameters. Mitral valve function can be assessed before and after induced valve insufficiency and after valve repair. Accordingly, techniques and instruments can be modified at early stages of prototype development. Methods In the diastole, the left atrium is passively filled through the reservoir. The loading pressure of the atrium and flow rates can be widely adjusted. To simulate the systole, a linear motor-driven piston pump promotes volume into the left ventricle and the aorta. An additional circulatory pump compensates for undesired total emptying of the heart chambers. The processor control of the linear pump allows for various settings of flow rate, velocity and even irregular rhythm. Twenty-one isolated porcine hearts were used. The leaflet movement was filmed using a universal serial bus (USB)-probe camera. Results With 80 mm stroke and 1 m/s speed, a volume of 150 ml can be pumped at a heart rate of up to 73 bpm. Cardiac outputs of up to 10.9 l/min can be achieved. Constant visualization and continuous measurements of the pressure gradients before and after the induction of mitral insufficiency and after repair allowed quantitative verification of repair quality under beating-heart conditions. Conclusions This model allows a controllable pulsation, loading and unloading of a porcine heart in a wide range. Thus, the function of the leaflets and repair results can be qualitatively and quantitatively evaluated under quasiphysiological conditions.

Einen Ansatz zur Unterstützung manueller Tätigkeiten stellen Exoskelette dar. Durch den Einsatz dieser Systeme lassen sich verschiedene biomechanische sowie arbeitsphysiologische Effekte erzielen. Verschiedene Faktoren haben hierauf Einfluss. In Studien mit einem Unterstützungssystem „Lucy“ hat sich gezeigt, dass mit physischer Unterstützung eine subjektive und quantitative Entlastung erzielt sowie die Konzentrationsleistung gesteigert werden kann. One approach to support manual activities are exoskeletons. Through the use of these systems, various biomechanical and work physiological effects can be achieved. Various factors influence this. In studies with a support system Lucy has been shown that physical support can provide subjective and quantitative relief and increase concentration.

Background Endocarditis remains one of the most threatening diagnoses in cardiac surgery and is still increasing. Particularly, device-related as well as prosthetic endocarditis appears to be on the rise. Early mortality and periprocedural complications are high jeopardizing the success of surgical efforts. We looked at the development of the numbers and the distribution of endocarditis in an all-comer analysis. Methods From 2003 to 2017, 752 patients with endocarditis were transferred to our cardiosurgical institution (mean age 65 ± 13 years; mean logistic EuroSCORE 28.01%; males 74.33%). A total of 89.49% of them were surgically treated; 30.01% redo cases thereof; and 9.17% had been operated previously for acute endocarditis. Results While the total number of cardiosurgical procedures remained relatively stable throughout the years, 20 patients were admitted in 2003 and 79 in 2017 yielding more than fourfold increase (p Conclusion Endocarditis remains a serious problem with high early mortality and morbidity. The vast increase of electrophysiological device implantations has resulted in an increase of tricuspid valve involvement. Liberalization of endocarditis prophylaxis, that is, more restrictive use of antibiotics in 2007 may have at least partially contributed to an increase of the individual risk to suffer from acute endocarditis. A renaissance of a stricter endocarditis–prophylaxis may thus be considered.

This study compares the composition, species richness and biomass of macrofaunal and algal assemblages on intertidal boulder shores as compared with those on adjacent rock-platforms, at six sites a...

OBJECTIVES To increase the safety of aortic valve replacement, we developed the ‘Caput medusae’ method, where the prosthesis is prefixed with circumferential tourniquets prior to knot tying. We assumed that an even distribution of forces may help reduce tissue damage. To confirm this theoretically, we compared forces between knots and tourniquets. METHODS The experimental set-up included a device with movable acrylic plates, a mounted valve and a set of sutures. Traction forces were measured with a luggage scale. Two different tourniquets were compared individually and as bundles of 15. Force–path curves were generated. Knotting and tourniquet forces of 18 staff surgeons were then compared. Both modalities were measured 10 times on 2 days, resulting in 40 observations per surgeon, or 360 observations per modality. RESULTS Polyvinyl chloride tourniquets were stiffer than silicone, expressed by a 1.5- to 1.7-fold higher regression-line slope. Fifteen simultaneous tubes produced force increments 7.9–8.9 times higher than their single counterparts. Overall knotting force was 13.64 ± 5.76 vs tourniquet 1.08 ± 0.48 N. Male surgeons’ knotting forces were higher compared to female staff (14.76 ± 6.01 vs 10.73 ± 3.74 N; P CONCLUSIONS Tourniquets exert less force on the tissue than knots. When distributed over the circumference, they can reduce local tension and avoid potential paravalvular leakage. Complete or partial use of tourniquets may thus be an additional option to enhance surgical safety.

Liquid preservation of the cold-sensitive boar sperm at a lesser temperature than the standard 17 °C would reduce bacterial growth and minimize the use of antibiotics. There was assessment, therefore, of the capacity of individual fatty acids bound to fatty acid free BSA to improve sperm survival at 6 °C because oxidative stress and lipid degradation are prominent detrimental factors. Different effects of the fatty acids were observed. Supplementation with naturally occurring fatty acids (linolenic, linoleic, oleic, palmitoleic acid), which may become metabolically incorporated into sperm lipids, increased the number of motile and progressively motile sperm after 2 days of storage during a thermo-resistance test (5 h at 38 °C) to that of control samples preserved at 17 °C in pure Beltsville Thawing Solution. With the exception of linolenic acid, all naturally occurring fatty acids enhanced the number of sperm with active mitochondria after 3 days of storage. Palmitoleic acid was the most effective supplement with effects already present when sperm were re-warmed for 30 min after 2 and 7 days of storage. The non-endogenous, non-integrated timnodonic acid (20:5) had no effect on sperm variables. Because the application of individual fatty acids attached to BSA had differing effects in preserving boar sperm at 6 °C, the use of combinations of fatty acids could be more efficacious than with use of natural lipid supplements for low temperature preservation of sperm.

During design of Class I components in Nuclear Power Plants, cumulative usage factors (CUF) are conservatively calculated to estimate fatigue damage, and results must be below the limits of the applicable codes. Nevertheless, when these results are used to evaluate the possibility of using these components for an extended life, the results are frequently above code limits. Many Nuclear Power Plants have installed commercial fatigue monitoring systems at critical components in order to assess transient severity and cycle count for life extension fatigue calculations among other reasons. Since the commissioning of the system, unexpected operation modes and thermal stratification was discovered and evaluations needed to be done. Findings, interpretations and solving are presented in this paper.

Laplace’s equation is solved for the confining potentials at the ends of a coaxial form of the Malmberg–Penning charged particle trap. The solution gives insight into the confinement and dynamics of the trapped particles. The solution employs several mathematical methods that are often studied in isolation. The connections between these methods are illustrated by solving the problem in different ways. This process also produces several new integral and series identities.

The creation of a small opening called the fusion pore is a necessary prerequisite for neurotransmitter release from synaptic vesicles. It is known that high intensity electric fields can create pores in vesicles by a process called electroporation. Due to the presence of charged phosphatidylserine (PS) molecules on the inner leaflet of the cell membrane, an electric field that is strong enough to cause electroporation of a synaptic vesicle might be present. It was shown by K. Rosenheck [K. Rosenheck. Biophys J 75, 1237-1243 (1998)] that in a planar geometry, fields sufficient to cause electroporation can occur at intermembrane separations of less than approximately 3 nm. It is frequently found, however, that the cell membrane is not planar but caves inward at the locations where a vesicle is close to it. Indentation of the cell membrane in the fusion region was modelled as a hemisphere and a theoretical study of the electric field in the vicinity of the cell membrane taking into account the screening effect of dissolved ions in the cytoplasm was performed. It was discovered that fields crossing the electroporation threshold occurred at a distance of 2 nm or less, supporting the claim that electroporation could be a possible mechanism for fusion pore formation.

A model for electron relaxation in a quantum dot, including a nonradiative pathway through a point defect, is presented, using time-dependent perturbation theory. The results obtained here extend previous work [Phys. Rev. B 51, 14 532 (1995)] to the experimentally relevant low-temperature regime. It is found that relaxation through defects may circumvent the phonon bottleneck predicted for ideal nanometer-scale quantum dot structures even at low temperatures. \textcopyright{} 1996 The American Physical Society.

It is demonstrated that finding a parent Hamiltonian for the chiral spin liquid remains an open problem. The one existing solution in the literature [Ann. Phys. 191 (1989) 163] is shown to fail both numerically and analytically, due to a non-commutativity of certain lattice sums.

Ligands for E-selectin and P-selectin (E-lig and P-lig) are induced on CD4+ T cells upon differentiation into effector T cells. Glycosyltransferases, especially α 1,3-fucosyltransferase VII (FucT-VII) and core 2 β1,6-N-acetyl-glycosaminyltransferase I (C2GlcNAcT-I), are critical for their synthesis. We here analysed the signals that control the expression of E-lig, P-lig and mRNA coding for FucT-VII and C2GlcNAcT-I. In line with previous reports, we found that P-lig expression correlates with the regulation of C2GlcNAcT-I, whereas E-lig expression can occur at low levels of C2GlcNAcT-I mRNA but requires high FucT-VII mRNA expression. Interestingly, the two enzymes are regulated by different signals. Activation-induced C2GlcNAcT-I up-regulation under permissive (T helper type 1) conditions was strongly reduced by cyclosporin A (CsA), suggesting the involvement of T-cell receptor-dependent, calcineurin/NFAT-dependent signals in combination with interleukin-12 (IL-12) -mediated signals in the regulation of C2GlcNAcT-I. In contrast, expression of FucT-VII mRNA was not significantly inhibited by CsA. Interleukin-4 inhibited the expression of FucT-VII but IL-2 and IL-7 were found to support induction of FucT-VII and E-lig. E-selectin, P-selectin and their ligands initially appeared to have rather overlapping functions. These findings however, unravel striking differences in the regulation of E-lig and P-lig expression, dictated by the dominance of FucT-VII and C2GlcNAcT-I, respectively, and their dependency on signals from either promiscuous or homeostatic cytokines (FucT-VII) or a strong T-cell receptor signal in combination with inflammatory cytokines in case of C2GlcNAcT-I.

We construct a parent Hamiltonian for the family of non-Abelian chiral spin liquids proposed recently by two of us [PRL 102, 207203 (2009)], which includes the Abelian chiral spin liquid proposed by Kalmeyer and Laughlin, as the special case S=1/2. As we use a circular disk geometry with an open boundary, both the annihilation operators we identify and the Hamiltonians we construct from these are exact only in the thermodynamic limit., 5+2 pages, no figures. Version 2: two references added

In this paper the applications, detailed in previous works, of ultrasonic transducers with the addition of axicon lenses are extended. Axicon lenses were manufactured to generate an angular refracted beam in order to study defectology in welds and other components. To achieve greater depth of focus while maintaining a relationship between focus depth and near field (F/N) less than 0.4, larger diameter transducers were used. Furthermore, its effect on the focus diameter (dF) was also analyzed. For different combinations of lens-transducer, diagrams of axial and transverse sound pressure distribution were obtained. At last, several practical applications are shown where it is possible to exploit the advantages that these transducers offer; for example: sizing of shallow cracks, high resolution corrosion mapping simulation, etc.

The present work refers to the welding inspection of the brackets of Atucha I Nuclear Power Plant’s Pressure Vessel (RPV) using the wet fluorescent magnetic particles technique (MT). Due to limited access and high radiation levels in the inspection area, it was necessary to automate the testing and use non conventional magnetization techniques. This paper describes the design and implementation of an automated inspection device and the tests carried out on the mock‐up to set up the system. Also, magnetization techniques used are described, explaining in detail the non conventional technique of magnetization by current plates and the use of magnetic field concentrators to increase the field values in the area of interest. Finally, the device mounted on the RPV, used to inspect the bracket’s weld, and the results achieved from the inspection are shown.

We construct a Hamiltonian that singles out the chiral spin liquid on a square lattice with periodic boundary conditions as the exact and, apart from the two-fold topological degeneracy, unique ground state., Comment: 5 pages, no figures

The first calculation of the true ground state of the parent Hamiltonian proposed by Laughlin [Laughlin, Ann. Phys. 191, 163 (1989)] for the $m=2$ fractional quantum Hall state on a torus is presented. Laughlin's model is generalized to the case of a system in a ladder geometry and rewritten in terms of familiar spin-spin interactions, demonstrating that the model corresponds to a long-range Heisenberg Hamiltonian with an additional four-site interaction. The exact diagonalization of the Hamiltonian is performed to extract the energies, correlation functions, sublattice magnetization, and overlap with the quantum Hall state. Our results confirm the recent work showing that the model is not exact [Schroeter, Ann. Phys. 310, 155 (2004)] and also show it to be not without merit: the overlap between the quantum Hall (QH) state and exact ground state approaches the significant value of 0.83 in the limit that the ladder becomes infinitely long.

A realistic model for the electronic structure of ${\mathrm{SrRuO}}_{3}$ is examined to determine the possibility of orbital antiferromagnetic order in this material. By calculating the susceptibility to orbital and spin antiferromagnetic order, it is shown that the band structure of ${\mathrm{SrRuO}}_{3}$ serves to destabilize the N\'eel ordered state and that the susceptibility to orbital antiferromagnetic order is larger over a range of doping. The resultant orbital antiferromagnetic state consists of coupled two-dimensional planes. The effect of the coupling on the planar system is calculated; the energy shifts of different configurations depend only on the total current in the sample and are linear in this quantity. An orbital antiferromagnetic ground state is found which has no net current flowing along the bonds.

We propose that the pseudogap state observed in the transition metal oxides can be explained by a three-dimensional flux state, which exhibits spontaneously generated currents in its ground state due to electron-electron correlations. We compare the energy of the flux state to other classes of mean field states, and find that it is stabilized over a wide range of $t$ and $\delta$. The signature of the state will be peaks in the neutron diffraction spectra, the location and intensity of which are presented. The dependence of the pseudogap in the optical conductivity is calculated based on the parameters in the model., Comment: submitted to Phys. Rev. B on January 8, 2002