Colonic permeability is increased in non-cirrhotic patients with nonalcoholic fatty liver disease.

BACKGROUND AND AIM: Intestinal permeability (IP) plays an important role in the pathophysiology of nonalcoholic fatty liver disease (NAFLD). We assessed site-specific (gastroduodenum, small intestine, colon and whole gut) IP in NAFLD patients and healthy controls (HC) and its association with the degree of hepatic steatosis, hepatic fibrosis and dietary composition in these NAFLD patients. METHODS: In vivo site-specific IP was analysed with a validated multi-sugar test in NAFLD patients and HC. Furthermore, in NAFLD patients, hepatic steatosis (chemical shift MRI), hepatic fibrosis (transient elastography) and dietary composition (food frequency questionnaire) were assessed. RESULTS: Fifty-two NAFLD patients and forty-six HC were included in this study. Small intestinal (P <0.001), colonic (P = 0.004) and whole gut (P <0.001) permeability were increased in NAFLD patients compared to HC. Furthermore, colonic permeability (P = 0.029) was significantly higher in NAFLD patients with clinically significant fibrosis compared to those without. Colonic permeability remained positively associated with the presence of clinically significant fibrosis (P = 0.017) after adjustment for age, sex and BMI. CONCLUSION: Colonic permeability is increased in at least a subset of NAFLD patients compared to HC and is independently associated with clinically significant NAFLD fibrosis.

Developing a patient portal for haematology patients requires involvement of all stakeholders and a customised design, tailored to the individual needs.

BACKGROUND: Electronic patient portals are increasingly being implemented, also in (haemato) oncology. However, portal usage is low and depends on user and provider engagement. We explored wishes, expectations and thoughts of patients with a haematologic malignancy and their physicians with regard to the electronic patient portal. METHODS: Based on insights from literature and a focus group discussion we built a 44-item questionnaire. This questionnaire was spread amongst patients with a haematologic malignancy at the outpatient clinic that was not yet exposed to patient portal facilities. Haematologists completed a questionnaire based on literature. RESULTS: Patients were interested in many different types of access to information and portal functionalities. However, their opinions varied about the provision of access to the portal to other people, the role of the physician, possibilities for communication via the portal and timing of access. The physicians acknowledged the relevance of the electronic patient portal, but had some worries about the patients' autonomous information handling, organizational and technical issues. Patients frequently expressed to be open about the potential of the patient portal to orchestrate their care. Nevertheless, most physicians appreciated their supporting role towards the patient. CONCLUSIONS: Patients and physicians appreciated the electronic patient portal. Both groups need to be involved in further portal development to improve engagement by meeting patients' wishes, taking into account organizational and professional issues and managing expectations for both parties. To fit various patient profiles, portal design should be flexible and individualized. Further research should focus on the perceived added value and the impact on patient related outcome measures of portals.

Efficient free-space read-out of WGM lasers using circular micromirrors.

Lasing from whispering-gallery mode (WGM) resonators occurs omnidirectional in azimuthal plane. Most applications of WGM resonators require spectral analysis with off-chip detectors, where in-plane emission and beam divergence hinder efficient detection. We demonstrate redirecting WGM laser emission from all azimuthal angles using a circular micromirror placed around the cavity. By collecting reflections off the micromirror via free-space optics, read-out intensity improved by one order of magnitude. Blocking vertically emitted spontaneous emission and recording reflections off the micromirror only, signal-to-noise ratio improved from 4.6 dB to 15 dB. Our read-out concept may be applied to arbitrary WGM cavity geometries without deteriorating the cavity's quality factor.

Densely Packed Microgoblet Laser Pairs for Cross-Referenced Biomolecular Detection.

Microgoblet laser pairs are presented for cross-referenced on-chip biomolecular sensing. Parallel readout of the micro-lasers facilitates effective mutual filtering of highly localized refractive index and temperature fluctuations in the analyte. Cross-referenced detection of two different types of proteins and complete chemical transducer reconfiguration is demonstrated. Selective surface functionalization of the individual lasers with high spatial accuracy is achieved by aligned microcontact stamping.

On-chip microlasers for biomolecular detection via highly localized deposition of a multifunctional phospholipid ink.

We report on a novel approach to realize on-chip microlasers, by applying highly localized and material-saving surface functionalization of passive photonic whispering gallery mode microresonators. We apply dip-pen nanolithography on a true three-dimensional structure. We coat solely the light-guiding circumference of pre-fabricated poly(methyl methacrylate) resonators with a multifunctional molecular ink. The functionalization is performed in one single fabrication step and simultaneously provides optical gain as well as molecular binding selectivity. This allows for a direct and flexible realization of on-chip microlasers, which can be utilized as biosensors in optofluidic lab-on-a-chip applications. In a proof-of-concept we show how this highly localized molecule deposition suffices for low-threshold lasing in air and water, and demonstrate the capability of the ink-lasers as biosensors in a biotin-streptavidin binding experiment.

Pump spot size dependent lasing threshold in organic semiconductor DFB lasers fabricated via nanograting transfer.

Optically excited organic semiconductor distributed feedback (DFB) lasers enable efficient lasing in the visible spectrum. Here, we report on the rapid and parallel fabrication of DFB lasers via transferring a nanograting structure from a flexible mold onto an unstructured film of the organic gain material. This geometrically well-defined structure allows for a systematic investigation of the laser threshold behavior. The laser thresholds for these devices show a strong dependence on the pump spot diameter. This experimental finding is in good qualitative agreement with calculations based on coupled-wave theory. With further investigations on various DFB laser geometries prepared by different routes and based on different organic gain materials, we found that these findings are quite general. This is important for the comparison of threshold values of various devices characterized under different excitation areas.

Diffusion driven optofluidic dye lasers encapsulated into polymer chips.

Lab-on-a-chip systems made of polymers are promising for the integration of active optical elements, enabling e.g. on-chip excitation of fluorescent markers or spectroscopy. In this work we present diffusion operation of tunable optofluidic dye lasers in a polymer foil. We demonstrate that these first order distributed feedback lasers can be operated for more than 90 min at a pulse repetition rate of 2 Hz without fluidic pumping. Ultra-high output pulse energies of more than 10 µJ and laser thresholds of 2 µJ are achieved for resonator lengths of 3 mm. By introducing comparatively large on-chip dye solution reservoirs, the required exchange of dye molecules is accomplished solely by diffusion. Polymer chips the size of a microscope cover slip (18 × 18 mm(2)) were fabricated in batches on a wafer using a commercially available polymer (TOPAS(®) Cyclic Olefin Copolymer). Thermal imprinting of micro- and nanoscale structures into 100 µm foils simultaneously defines photonic resonators, liquid-core waveguides, and fluidic reservoirs. Subsequently, the fluidic structures are sealed with another 220 µm foil by thermal bonding. Tunability of laser output wavelengths over a spectral range of 24 nm on a single chip is accomplished by varying the laser grating period in steps of 2 nm. Low-cost manufacturing suitable for mass production, wide laser tunability, ultra-high output pulse energies, and long operation times without external fluidic pumping make these on-chip lasers suitable for a wide range of lab-on-a-chip applications, e.g. on-chip spectroscopy, biosensing, excitation of fluorescent markers, or surface enhanced Raman spectroscopy (SERS).