Tunable non-integer high-harmonic generation in a topological insulator.

When intense lightwaves accelerate electrons through a solid, the emerging high-order harmonic (HH) radiation offers key insights into the material1-11. Sub-optical-cycle dynamics-such as dynamical Bloch oscillations2-5, quasiparticle collisions6,12, valley pseudospin switching13 and heating of Dirac gases10-leave fingerprints in the HH spectra of conventional solids. Topologically non-trivial matter14,15 with invariants that are robust against imperfections has been predicted to support unconventional HH generation16-20. Here we experimentally demonstrate HH generation in a three-dimensional topological insulator-bismuth telluride. The frequency of the terahertz driving field sharply discriminates between HH generation from the bulk and from the topological surface, where the unique combination of long scattering times owing to spin-momentum locking17 and the quasi-relativistic dispersion enables unusually efficient HH generation. Intriguingly, all observed orders can be continuously shifted to arbitrary non-integer multiples of the driving frequency by varying the carrier-envelope phase of the driving field-in line with quantum theory. The anomalous Berry curvature warranted by the non-trivial topology enforces meandering ballistic trajectories of the Dirac fermions, causing a hallmark polarization pattern of the HH emission. Our study provides a platform to explore topology and relativistic quantum physics in strong-field control, and could lead to non-dissipative topological electronics at infrared frequencies.

Both operator and heat treatment determine the centring ability of Reciproc® files in vitro.

OBJECTIVES: To determine the shaping ability of reciprocating files without/with post-manufacturing heat treatment (Reciproc®/Reciproc blue®, VDW) when used by six operators of similar level of experience. MATERIALS AND METHODS: Plastic training blocs with curved root canals (5 mm radius, 55° angle) were mounted in a dental manikin. Each operator prepared six specimens with each instrument system using the file sizes R25, R40 and R50 consecutively. Specimens were photographed, and deviations from the centre of the canal were measured at intervals of 0.5 mm and averaged for the apical, middle and coronal part of the canal. Data were tested for significance using the Mann-Whitney U test and two-way ANOVA with instrument systems and operators serving as factors. RESULTS: Deviations were observed towards the outer curvature in the apical and coronal and to the inner curvature in the middle segment of the canal. They were larger after using larger size instruments and were smaller when using Reciproc blue® compared to Reciproc®. Significant differences among operators were observed in the middle (all sizes) and coronal part of the canals (only sizes R25 und R40). Coronally, interaction between the main factors was significant as well. CONCLUSIONS: Post-manufacturing heat treatment significantly improved shaping ability of the reciprocating file system Reciproc®. The observed differences among operators suggest the possibility of further improvement by providing specific training for prospective users. CLINICAL RELEVANCE: Maintenance of root canal curvature may be improved by using post-manufacturing heat-treated instruments, but specific training should be recommended as well.

[Enzymatic débridement as a treatment option for deep dermal burns of the hand]. / Enzymatisches Débridement als Therapieoption bei tiefdermalen Verbrennungen der Hand.

Burns and thermal injuries from other causes often affect exposed body regions such as the hands. Besides aesthetic aspects, deep dermal burns of the skin are often critical from a functional point of view, especially for important subcutaneous structures. This article reports the course of two patients who received enzymatic debridement with bromelain-based salve as a treatment for deep grade burns of the hands.

Effects of cryopreservation on the epigenetic profile of cells.

Effective cryopreservation protocols are essential for long-term storage of cells and their subsequent clinical application. Freezing protocols are generally considered as safe; however, putative effects on epigenetic marks have not yet been studied in detail. While post-thaw cell survival rates have been used to evaluate the success of cryopreservation protocols, increasing evidence suggests that freezing may be associated with deviations from the physiological epigenetic marks with putative long-term effects on the cells and/or their derivatives. A better understanding of the underlying mechanisms would be beneficial for improving safety and effectiveness of freezing protocols. The purpose of this review is to provide current information regarding epigenetic alterations (DNA methylation and histone modification patterns) associated with cryopreservation.

[Attitude towards organ and tissue donation in Europe : Prerequisite for osteochondral allograft treatment]. / Bereitschaft zur Organ- und Gewebespende in Europa : Voraussetzung für die Behandlung mit osteochrondralen Allografts.

BACKGROUND: The biggest obstacle to overcome for routine treatment of various pathologies with fresh osteochondral allograft is the availability of tissue for transplantation. Large fresh osteochondral allografts are usually harvested from organ donors, but in contrast to organs, tissues can be procured after cardiac arrest. OBJECTIVE: Medical staff as well the general public are much less aware of the possibilities and requirements of tissue donation compared to organ donation. This review aims to highlight the current situation of organ and tissue donation in Europe and to raise this much needed awareness. MATERIAL AND METHODS: For this research, PubMed database was scanned using the terms "tissue/organ donation", "bone donation/transplantation", "cartilage transplantation/allografts" and "osteochrondral allografts". RESULTS: Relatives of potential donors are often not approached because physicians and nurses do not feel sufficiently prepared for this task and, thus, are reluctant to address this topic. Different options could alleviate the pressure medical staff is feeling. Furthermore, there are different factors influencing consent that can be addressed to increase donation rates. CONCLUSION: Currently, a lot of potential concerning musculoskeletal tissue grafts remains unused. Most importantly, families should be encouraged to speak about their potenzial will to donate and educational programs should be established to increase trust in organ and tissue donation and the allocation system and to increase knowledge about the importance of transplantation medicine. But joined efforts of different parts of the medical systems and different organizations involved in tissue transplantation should improve the situation for patients waiting for much needed transplants.

Active control of the nucleation temperature enhances freezing survival of multipotent mesenchymal stromal cells.

Cryopreservation is a technique that has been extensively used for storage of multipotent mesenchymal stromal cells (MSCs) in regenerative medicine. Therefore, improving current cryopreservation procedures in terms of increasing cell viability and functionality is important. In this study, we optimized the cryopreservation protocol of MSCs derived from the common marmoset Callithrix jacchus (cj), which can be used as a non-human primate model in various pathological and transplantation studies and have a great potential for regenerative medicine. We have investigated the effect of the active control of the nucleation temperature using induced nucleation at a broad range of temperatures and two different dimethylsulfoxide concentrations (Me2SO, 5% (v/v) and 10%, (v/v)) to evaluate the overall effect on the viability, metabolic activity and recovery of cells after thawing. Survival rate and metabolic activity displayed an optimum when ice formation was induced at -10 °C. Cryomicroscopy studies indicated differences in ice crystal morphologies as well as differences in intracellular ice formation with different nucleation temperatures. High subzero nucleation temperatures resulted in larger extracellular ice crystals and cellular dehydration, whereas low subzero nucleation temperatures resulted in smaller ice crystals and intracellular ice formation.

Comprehensive bio-imaging using myocardial perfusion reserve index during cardiac magnetic resonance imaging and high-sensitive troponin T for the prediction of outcomes in heart transplant recipients.

We sought to determine the ability of quantitative myocardial perfusion reserve index (MPRI) by cardiac magnetic resonance (CMR) and high-sensitive troponin T (hsTnT) for the prediction of cardiac allograft vasculopathy (CAV) and cardiac outcomes in heart transplant (HT) recipients. In 108 consecutive HT recipients (organ age 4.1±4.7 years, 25 [23%] with diabetes mellitus) who underwent cardiac catheterization, CAV grade by International Society for Heart & Lung Transplantation (ISHLT) criteria, MPRI, late gadolinium enhancement (LGE) and hsTnT values were obtained. Outcome data including cardiac death and urgent revascularization ("hard cardiac events") and revascularization procedures were prospectively collected. During a follow-up duration of 4.2±1.4 years, seven patients experienced hard cardiac events and 11 patients underwent elective revascularization procedures. By multivariable analysis, hsTnT and MPRI both independently predicted cardiac events, surpassing the value of LGE and CAV by ISHLT criteria. Furthermore, hsTnT and MPRI provided complementary value. Thus, patients with high hsTnT and low MPRI showed the highest rates of cardiac events (annual event rate=14.5%), while those with low hsTnT and high MPRI exhibited excellent outcomes (annual event rate=0%). In conclusion, comprehensive "bio-imaging" using hsTnT, as a marker of myocardial microinjury, and CMR, as a marker of microvascular integrity and myocardial damage by LGE, may aid personalized risk-stratification in HT recipients.

Long-term outcome after heart transplantation predicted by quantitative myocardial blush grade in coronary angiography.

The purpose of our study was to investigate whether the quantification of myocardial blush grade (MBG) during surveillance coronary angiography can predict long-term outcome after heart transplantation (HT). In 105 HT recipients who underwent cardiac catheterization, cardiac allograft vasculopathy (CAV) was assessed visually using the ISHLT grading scale (prospective cohort study). MBG was quantified by dividing the plateau of contrast agent gray-level intensity (G(max)) by the time-to-peak intensity (T(max)). In a subgroup (n = 72), myocardial perfusion index by cardiac magnetic resonance imaging (CMR) was assessed. During a mean follow-up duration of 2.7 (standard deviation [SD] 1.0) years, 26 patients experienced cardiac events, including 7 with cardiac death and 19 who underwent coronary revascularization. G(max)/T(max) was related to CAV by ISHLT criteria and to subsequent cardiac events. By univariate analysis, patient age, organ age, CAV, MBG and myocardial perfusion index by CMR were all predictive for cardiac events. Multivariable analysis demonstrated that G(max)/T(max) provided the most robust prediction of cardiac death (hazard ratio [HR] = 0.2, 95% confidence interval [CI] = 0.06-0.64, p < 0.01) and cardiac events (HR = 0.52, 95% CI = 0.32-0.84, p < 0.01), beyond clinical parameters and the presence of CAV. G(max)/T(max) is a valuable surrogate parameter of microvascular integrity, which is associated with cardiac death and revascularization procedures after HT.

Sedation training using a human patient simulator.

High-fidelity simulation uses simulators that combine all of the physiological and pharmacological responses of a human in a manikin. These simulators change and respond to the users and trainees. Using simulators for teaching sedation in the field of gastroenterology unifies all the advantages of manikins. To understand the pharmacological and pharmacodynamical principles of drugs used for sedation in different clinical scenarios, such as cardiopulmonary diseases, a high-fidelity simulator is extremely useful. Respiratory complications and airway problems are the main side effects when using sedatives. To overcome these problems, exercise of precautionary measures are highly demanded to avoid hazards. High-fidelity simulation is increasingly being used for the development of crisis resource management. There are still limitations in using simulators for education and training. At present, applying simulation for teaching is expensive. The start-up costs and the expenses for instructors and technicians are high. Moreover, no direct evidence has demonstrated that simulation training improves actual patient safety outcome and, therefore, a lot of research in this field remains to be done. Even so, confidence is growing in the validity of medical simulation as the training tool of the future.

Super-resolution lightwave tomography of electronic bands in quantum materials.

Searching for quantum functionalities requires access to the electronic structure, constituting the foundation of exquisite spin-valley-electronic, topological, and many-body effects. All-optical band-structure reconstruction could directly connect electronic structure with the coveted quantum phenomena if strong lightwaves transported localized electrons within preselected bands. Here, we demonstrate that harmonic sideband (HSB) generation in monolayer tungsten diselenide creates distinct electronic interference combs in momentum space. Locating these momentum combs in spectroscopy enables super-resolution tomography of key band-structure details in situ. We experimentally tuned the optical-driver frequency by a full octave and show that the predicted super-resolution manifests in a critical intensity and frequency dependence of HSBs. Our concept offers a practical, all-optical, fully three-dimensional tomography of electronic structure even in microscopically small quantum materials, band by band.

[Influence of the donor age on graft survival : Is the demographic change also important for corneal tissue donation?] / Einfluss des Donoralters auf das Transplantatüberleben : Ist der demografische Wandel auch von Bedeutung für die Augenhornhautgewebespende?

The success of corneal transplantation highly depends on the quality of the used graft. Various factors play a crucial role such as a perfect stroma without optically relevant, centrally located cloudiness or changes (e. g. scars) or an adherent Descemet membrane. One of the most important parameters is the quality of the endothelial cell layer with a sufficiently large endothelial cell count. An open question is so far whether the donor age affects corneal quality and therefore has an impact on the success of transplantation. A comprehensive review of the available literature revealed that a large amount of scientific data on the influence of donor age exist to answer this question. In a variety of studies, no significant dependence of graft quality of donor age could be detected. Rather the studies prove that graft survival depends primarily on the state of the endothelial cell layer, and postoperative endothelial cell loss must be considered as a major cause of graft failure. Extensive quality assurance procedures in tissue preparation and cornea processing in the eye banks in Germany (Europe) ensures that only corneas with tested high quality are allocated for transplantation regardless of the donor age. Against the background of an aging population, the use of grafts from older donors should not be waived.

Fresh osteochondral allografts-procurement and tissue donation in Europe.

Fresh osteochondral allografts are a well-established treatment for large, full-thickness cartilage defects. The clinical outcome for carefully selected patients is very favorable, especially for the young and active and graft survival up to 25 years has been described in the literature. Furthermore, a high patient satisfaction rate has been reported, but the biggest obstacle to overcome is the availability of tissue for transplantation. Large fresh bone allografts for cartilage damage repair only can be harvested from organ donors following organ removal or cadaveric donors, preferably in the setting of an operation room to minimize possible contamination of the tissue. Apart from the logistic challenges this entails, an experienced recovery team is needed. Furthermore, the public as well as medical staff is much less aware of the possibility and requirements of tissue donation than organ donation and families of deceased are rarely approached for bone and cartilage donation. This review aims to highlight the current situation of organ and tissue donation in Europe with special focus on the processing of bones and possible safety and quality concerns. We analyze what may prevent consent and what might be done to improve the situation of tissue donation.

Exogenous antigen containing perivascular phagocytes induce a non-encephalitogenic extravasation of primed lymphocytes.

Recent evidence suggests that T-lymphocyte extravasation and CNS-parenchymal infiltration during autoimmune disease might be regulated by antigen-presenting (ED2(+)) cerebral/spinal perivascular phagocytes (CPP/SPP). Since the massive erythrocytic and leukocytic infiltrates in the CNS of rats with experimental allergic encephalomyelitis do not allow a precise differentiation between CPP/SPP and the invading cells in the Virchow-Robin space, we developed a new immune-response model whereby the extravasation of T-lymphocytes was not followed by other blood cells. Adult Lewis rats were sensitized to horseradish peroxidase (HRP). Subsequent intracerebroventricular (i.c.v.) injections of HRP and/or Fluoro-Emerald (FE) served to: (1) challenge the primed T-lymphocytes and (2) label the CPP/SPP for additional immunocytochemical analysis. We found that 24 h and 3 days after single, double, or triple antigen boosting T-lymphocytes (R73(+), W3/25(+), OX50(+)) entered the Virchow-Robin space but did not break through the astrocytic glia limitans. Instead they adhered to HRP-containing activated CPP/SPP (mabs OX-6(+), SILK6(+), CD40(+), CD80(+), CD86(+)). This selective contact was mediated neither by cell adhesion molecules (P-selectin, ICAM-1, VCAM-1), nor promoted by chemokine receptors (CCR1, CCR5) or chemokines (monocyte chemoattractant protein (MCP)-1, MIP-1alpha, MIP-1beta, RANTES). This non-inflammatory, but antigen-dependent lymphocyte extravasation provides optimal conditions to further study the CNS immune response.

Enzyme histochemical studies on the pathological changes in human Sertoli cells.

Two forms of human Sertoli cell disorders were characterized enzyme histochemically from the testicular biopsy material of infertile and subfertile patients. Sertoli cell asthenia: a slight injury of the Sertoli cell with exfoliation of individual germ cells; marked by the rarefaction of reaction zones of thiamine pyrophosphatase (TPPase) and a decrease in lactate dehydrogenase (LDH). Sertoli cell insufficiency: severe Sertoli cell damage with the formation of a "puff" and a heavy exfoliation of germ cells (dislocation of Sertoli cell nucleus and cytoplasm along with the related germ cells into the lumen of seminiferous tubule); marked by a heterogeneous activity pattern of TPPase, the disappearance of LDH, maintenance of a slightly weakened activity of alkaline phosphatase, and an increase of acid phosphatase. In the case of Sertoli-cell-only syndrome, the high prismatic Sertoli cells showed strong acid phosphatase activity with scattered weak TPPase reaction, whereas the flat or cube-like Sertoli cells exhibited weak acid phosphatase activity with only one small round reaction zone of TPPase in each cell. In addition, the frequency of the occurrence of Sertoli cell asthenia, Sertoli cell insufficiency, and Sertoli-cell-only syndrome is reported, and its correlation with the andrological diseases discussed.

Demonstration of thiamine pyrophosphatase in human germ cells and Sertoli cells, a histochemical study.

The distribution of thiamine pyrophosphatase (TPPase) was studied in the human testicular biopsy tissue with the help of a modified histochemical gel method. The spermatogonia showed a large round strongly positive reaction zone in the supranuclear region. The pachytene spermatocytes exhibited a large semicircular TPPase reaction zone around the nucleus directing towards the lumen. The early round spermatids were characterized by a small, round, and weak supranuclear reaction zone. The elongated late spermatids were devoid of TPPase activity. The Sertoli cells possessed a "streamer" like formation of strong TPPase activity spreading from basal to apical portion.

Effect of storage media on microleakage of five dentin bonding agents.

The objective of this study was to investigate the effect of different storage media on microleakage at the gingival margin of mixed Class V composite restorations. Human molars were either used immediately after extraction (control group) or after a 3-4 wk storage period in 1% chloramine, 70% ethanol, 10% formalin, or 0.1% thymol. Class V cavities with cervical margins in cementum or dentin were prepared and restored with a microfill composite using five different dentin bonding agents. After thermocycling (1440 x from 5 degrees C to 55 degrees C) and basic fuchsin staining, the depth of dye penetration at the gingival margins was determined and ranked on a scale of 0 to 4. Class V restorations in teeth stored in formalin showed significantly less microleakage (mean leakage score, MLS = 1.7) than restorations in freshly extracted teeth (control group; MLS = 3.1). Microleakage scores in teeth stored in chloramine (MLS = 2.7), ethanol (MLS = 3.0) or thymol (MLS = 3.2) were not significantly different from the microleakage scores in the control group. The improvement of in vitro efficacy of dentin bonding agents when using extracted teeth stored in formalin is probably a result of collagen cross-linking by formaldehyde. Since such an alteration of the dentin does not reflect the condition of the substrate in vivo, extracted teeth assigned for in vitro evaluation of dentin bonding agents should not be stored in formalin. In teeth stored in 1% chloramine, the sums of ranks and the rank orders of the dentin bonding agents were comparable to those in freshly extracted teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Guidance of shrinkage vectors vs irradiation at reduced intensity for improving marginal seal of class V resin-based composite restorations in vitro.

This study evaluated the influence of radiation intensity on polymerization of a resin-based composite (RBC) and compared the influence of guidance of shrinkage vectors vs irradiation at reduced light intensity on the marginal seal of Class V RBC restorations in vitro. The degree of cure was studied indirectly by measuring the Vickers hardness (1.96 N, 30 seconds) at the bottom of disc-shaped specimens 2 mm in height at different periods of time after light irradiation. After one hour, irradiation using a high-intensity curing light (Heliolux GTE, Vivadent, 600 mW/cm2) [HICL] from close distance for 20 seconds, 40 seconds or 60 seconds or a low-intensity curing light (Vivalux, 250 mW/cm2) [LICL] from close distance for 60 seconds produced higher hardness values compared to 20 seconds or 40 seconds using the LICL or using the HICL from a distance of 10 mm. After three and 24 hours, higher hardness was observed for all irradiation protocols. After 24 hours, only specimens irradiated by the HICL for 20 seconds or 40 seconds from 10 mm distance featured significantly lower hardness compared to the remaining curing modes. The influence of different irradiation strategies on marginal seal of Class V RBC restorations was evaluated in vitro using dye penetration after water storage (60 days, 37 degrees C) and thermocycling (2500 cycles 5 degrees-55 degrees C). The HICL produced more dye penetration than the LICL. Placing the light tip directly over or 10 mm above the center of the cavity ("standard irradiation, ["distance irradiation"]") resulted in similar penetration values. In contrast, positioning the light tip apical to the cervical margin and moving it slowly to the center of the cavity ("cervical start irradiation") compromised the marginal seal.

Understanding the neuropsychiatric symptoms of Huntington's disease.

Huntington's disease (HD) is a neurodegenerative process that is manifest as deterioration in a person's motor control, cognition and emotional stability. Emotional instability is reflected through a variety of symptoms such as personality change, anxiety and irritability. These symptoms are complex and often poorly understood. Changes in the caudate are thought to contribute to psychiatric alterations seen in HD patients. An understanding of common psychiatric disorders seen in HD allows nurses to develop appropriate interventions.

[Indication and clinical value of vesiculodeferentography concerning urologic-andrologic diseases (author's transl)]. / Indikation und Bedeutung der Vesiculo-Deferentographie bei urologisch-andrologischen Erkrankungen.

There are 29 cases of vesiculodeferentography (VDG) (1962-1975) presented. The very indication of VDG was the evaluation of azoospermia due to occlusion of the vas deferens, in addition to other urologic diseases. Especially from the andrologic point of view the various forms of occlusion-azoospermia are classified and analyzed. It is pointed out, that the rete testis region is not to be elucidated by VDG.