De coloninterpositie als mogelijkheid tot reconstructie van de oesophagus

Ondanks jarenlang klinisch en experimenteel onderzoek is nog steeds niet die chirurgische methode van oesophagusreconstructie gevonden, die niet alleen een lage operatiemortaliteit en morbiditeit heeft, maar ook een blijvend goed func~ tioneel resultaat. Bestudering van de literatuur over dit onderwerp leert, dat geen van de huidige reconstructiemogelijkheden van de oesophagus in dit opzicht volledig voldoet. De maag als reconstructiemogelijkheid heeft als nadeel, dat hierbij vaak reflux van de maaginhoud optreedt, met als gevolg een oesophagitis met grote kans op stenosevorming. Tevens doen zich ernstige technische problemen voor wanneer grote afstanden moeten worden overbrugd (Sherman en Mahoney, 1955). Het gebruik van jejunum als reconstructiemogelijkheid vindt onder andere zijn beperking hierin, dat door een tekort mesenterium grote afstanden vaak niet kunnen worden overbrugd, terwijl door een alkalische reflux ook hier een oesophagilis met stenosering kan optreden (Sherman en Mahoney, 1955). Reconstructie met behulp van huidlappen vindt thans vrijwel uitsluitend toepassing bij carcinomen van de hypopharynx en cervicale oesophagus (Ong, 1971). Het vrije transplantaat (bijvoorbeeld ileum) wordt nog maar op zeer beperkte schaal klinisch toegepast. Over de resultaten is weinig bekend (Ong, 1971). Tenslotte kan als reconstructie van de oesophagus een deel van het colon gebruikt worden. In het algemeen worden hierover in de literatuur gunstige resultaten vermeld. Een nadeel zou de hierbij optredende gallige regurgitatie zijn (Hang, 1967). Het doel van deze studie is om aan eigen patientenmateriaal na te gaan of de coloninterpositie voldoet als mogelijkheid tot reconstructie van de oesophagus

Blue light phototherapy for Psoriasis from a systems biology perspective

This work analyses the effect of UV-free blue light (BL) irradiation of the skin using mathematical modelling. Prior research has shown that blue light reduces the proliferation of keratinocytes by inducing their differentiation, and causes apoptosis of lymphocytes. The effects of blue light on these cells make it an attractive phototherapy alternative for inflammatory skin conditions, such as psoriasis. Nevertheless, the exact process by which BL affects these cells is not fully understood. A modelling approach may give further insight to understanding how BL irradiation of psoriatic skin leads to the control of the disease. However, no mathematical model is available describing this phenomenon. Two deterministic models were therefore made to describe the epidermal kinetics and interaction between keratinocytes and lymphocytes under the effect of BL irradiation; focusing mainly on the case of psoriasis. We employed a systems biology approach to characterize the effect of BL irradiation of the skin. Since in phototherapy parameters such as fluence and power have a strong impact on the outcome, a parameter sensitivity analysis (PSA) was performed to estimate a range of fluence and power at which BL phototherapy could be successful. The models results suggest that the management of psoriasis is achieved by inducing symmetric differentiation of the keratinocytes in the epidermal proliferative compartment. It is observed that BL irradiation of psoriatic skin decreases the density of keratinocytes and transiently increases the density of lymphocytes, leading to the regulation of the interaction between these two cell types. The PSA of the models predicts that the higher the peak power the better the outcome of the BL phototherapy with a dose of 90J/cm2 per day. This systems biology approach provides additional insight into the use of BL phototherapy for inflammatory skin disorders

Lessons learned from computer models on blue light therapy for psoriasis vulgaris

Blue light irradiation has been clinically proven to reduce the symptoms of psoriasis vulgaris, a common chronic inflammatory skin disease that affects 2% - 3% of the world’s population. This dermatological condition is characterized by hyperproliferation and disturbed differentiation of keratinocytes, which is evident in lesional areas as thick flaky skin. The lesional areas also exhibit sustained inflammation, induced by immune cells, such as T cells and dendritic cells, infiltrating the affected skin. Blue light reduces the proliferation of keratinocytes and increases their differentiation in a wavelength and fluence dependent manner. Also, it induces apoptosis in T cells and suppresses the activation of dendritic cells. These effects can explain the symptom reduction after treatment. But, the efficacy shown in the clinical studies could be further improved by having a deeper understanding on the underlying mechanism of this therapeutic approach and optimizing the treatment regimens currently used. Diverse findings have been published in different studies of blue light therapy for psoriasis describing large, little or no therapeutic effect. These results may be due to variances in the main treatment parameters of the implemented protocols, i.e. fluence, intensity, and length of treatment. Computational methods can provide a suitable platform to investigate the complex interactions leading to the management of psoriasis by blue light therapy and optimize the treatment protocols. Here, we explore in silico the underlying mechanism of blue light irradiation of psoriatic skin and predict the outcome of a wide range of therapeutic regimens with varying fluence, intensity, and length of treatment. The computational model is defined by a set of ordinary differential equations describing the time evolution of keratinocytes as they move vertically through the layers of the epidermis. The results of our simulations suggest that the temporary decrease in the severity of psoriasis can be explained by the transient decline in the proliferative capacity of keratinocytes. However, it is still unclear how the effects of blue light on the immune system contribute to the reduction of psoriasis symptoms. Simulations implemented for several combinations of treatment parameters predict that high efficacy is achieved by protocols with long duration and high fluence levels, regardless of the chosen intensity. These predictions provide general guidelines for treatment. Our in silico approach constitutes a framework for testing diverse hypotheses on the underlying mechanism of blue light therapy and designing effective strategies for the treatment of psoriasis vulgaris

Room-temperature continuous wave lasing in deep-subwavelength metallic cavities under electrical injection

Plasmonic nanolasers and spasers continue to attract a great deal of interest from the physics and nanophotonics community, with the experimental observation of lasing as a focus of research. We report the observation of continuous wave lasing in metallic cavities of deep subwavelength sizes under electrical injection, operating at room temperature. The volume of the nanolaser is as small as 0.42¿3, where ¿ = 1.55 µm is the lasing wavelength. This demonstration will help answer the question of how small a nanolaser can be made, and will likely stimulate a wide range of fundamental studies in basic laser physics and quantum optics on truly subwavelength scales. In addition, such nanolasers may lead to many potential applications, such as on-chip integrated photonic systems for communication, computing, and detection

Transport Measurements on Nano-engineered Two Dimensional Superconducting Wire Networks

Superconducting triangular Nb wire networks with high normal-state resistance are fabricated by using a negative tone hydrogen silsesquioxane (HSQ) resist. Robust magnetoresistance oscillations are observed up to high magnetic fields and maintained at low temperatures, due to the eective reduction of wire dimensions. Well-defined dips appear at integral and rational values (1/2, 1/3, 1/4) of the reduced flux f = Phi/Phi_0, which is the first observation in the triangular wire networks. These results are well consistent with theoretical calculations for the reduced critical temperature as a function of f.Comment: 4 pages, 3 figure

Onsager coefficients of a Brownian Carnot cycle

We study a Brownian Carnot cycle introduced by T. Schmiedl and U. Seifert [Europhys. Lett. \textbf{81}, 20003 (2008)] from a viewpoint of the linear irreversible thermodynamics. By considering the entropy production rate of this cycle, we can determine thermodynamic forces and fluxes of the cycle and calculate the Onsager coefficients for general protocols, that is, arbitrary schedules to change the potential confining the Brownian particle. We show that these Onsager coefficients contain the information of the protocol shape and they satisfy the tight-coupling condition irrespective of whatever protocol shape we choose. These properties may give an explanation why the Curzon-Ahlborn efficiency often appears in the finite-time heat engines

Observation and Assignment of Silent and Higher Order Vibrations in the Infrared Transmission of C60 Crystals

We report the measurement of infrared transmission of large C60 single crystals. The spectra exhibit a very rich structure with over 180 vibrational absorptions visible in the 100 - 4000 cm-1 range. Many silent modes are observed to have become weakly IR-active. We also observe a large number of higher order combination modes. The temperature (77K - 300K) and pressure (0 - 25KBar) dependencies of these modes were measured and are presented. Careful analysis of the IR spectra in conjunction with Raman scattering data showing second order modes and neutron scattering data, allow the selection of the 46 vibrational modes C60. We are able to fit *all* of the first and second order data seen in the present IR spectra and the previously published Raman data (~300 lines total), using these 46 modes and their group theory allowed second order combinations.Comment: REVTEX v3.0 in LaTeX. 12 pages. 8 Figures by request. c60lon

Zero-bias conductance peak splitting due to multiband effect in tunneling spectroscopy

We study how the multiplicity of the Fermi surface affects the zero-bias peak in conductance spectra of tunneling spectroscopy. As case studies, we consider models for organic superconductors $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$ and (TMTSF)$_2$ClO$_4$. We find that multiplicity of the Fermi surfaces can lead to a splitting of the zero-bias conductance peak (ZBCP). We propose that the presence/absence of the ZBCP splitting is used as a probe to distinguish the pairing symmetry in $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$.Comment: 7 pages, 7 figure

Theory of charge transport in diffusive normal metal / unconventional singlet superconductor contacts

We analyze the transport properties of contacts between unconventional superconductor and normal diffusive metal in the framework of the extended circuit theory. We obtain a general boundary condition for the Keldysh-Nambu Green's functions at the interface that is valid for arbitrary transparencies of the interface. This allows us to investigate the voltage-dependent conductance (conductance spectrum) of a diffusive normal metal (DN)/ unconventional singlet superconductor junction in both ballistic and diffusive cases. For d-wave superconductor, we calculate conductance spectra numerically for different orientations of the junctions, resistances, Thouless energies in DN, and transparencies of the interface. We demonstrate that conductance spectra exhibit a variety of features including a $V$-shaped gap-like structure, zero bias conductance peak (ZBCP) and zero bias conductance dip (ZBCD). We show that two distinct mechanisms: (i) coherent Andreev reflection (CAR) in DN and (ii) formation of midgap Andreev bound state (MABS) at the interface of d-wave superconductors, are responsible for ZBCP, their relative importance being dependent on the angle $\alpha$ between the interface normal and the crystal axis of d-wave superconductors. For $\alpha=0$, the ZBCP is due to CAR in the junctions of low transparency with small Thouless energies, this is similar to the case of diffusive normal metal / insulator /s-wave superconductor junctions. With increase of $\alpha$ from zero to $\pi/4$, the MABS contribution to ZBCP becomes more prominent and the effect of CAR is gradually suppressed. Such complex spectral features shall be observable in conductance spectra of realistic high-$T_c$ junctions at very low temperature

Sex ratio biases in termites provide evidence for kin selection

Contains fulltext : 142755.pdf (publisher's version ) (Closed access)Molecular testing of tumor samples to guide treatment decisions is of increasing importance. Several drugs have been approved for treatment of molecularly defined subgroups of patients, and the number of agents requiring companion diagnostics for their prescription is expected to rapidly increase. The results of such testing directly influence the management of individual patients, with both false-negative and false-positive results being harmful for patients. In this respect, external quality assurance (EQA) programs are essential to guarantee optimal quality of testing. There are several EQA schemes available in Europe, but they vary in scope, size and execution. During a conference held in early 2012, medical oncologists, pathologists, geneticists, molecular biologists, EQA providers and representatives from pharmaceutical industries developed a guideline to harmonize the standards applied by EQA schemes in molecular pathology. The guideline comprises recommendations on the organization of an EQA scheme, defining the criteria for reference laboratories, requirements for EQA test samples and the number of samples that are needed for an EQA scheme. Furthermore, a scoring system is proposed and consequences of poor performance are formulated. Lastly, the contents of an EQA report, communication of the EQA results, EQA databases and participant manual are given