Reinforcement of colonic anastomoses with a collagenous double-layer matrix extracted from porcine dermis.

BACKGROUND: Anastomotic leakage is a major factor for morbidity in colorectal surgery. Anastomotic reinforcement with biological or synthetic materials has been claimed to be useful in preventing anastomotic leakage. METHODS: We evaluated a non-cross-linked collagenous matrix Bio-Gide (BG) for sealing colonic anastomoses in a rodent model. The animals were investigated for 4, 30 and 90 days. Macroscopic examination, histological examination and measurement of bursting pressure were performed. The anastomotic stricture rate was evaluated by radiographic contrast enema. RESULTS: Microscopically anastomoses sealed by BG showed impaired anastomotic healing. Blood vessel ingrowth and collagen deposition were decreased without reaching significance after 4 days. The anastomotic bursting pressure was significantly decreased (p = 0.0454) in the early phase of healing. Anastomotic neovascularization was significantly decreased compared to the control group after 30 (p = 0.0058) and 90 days (p = 0.0275). Although no difference in anastomotic stricture rate was evident, the rate of intra-abdominal adhesions was significantly increased after 30 (p = 0.0124) and 90 days (p = 0.0281). CONCLUSION: BG failed to improve colonic anastomotic healing. Early anastomotic healing was impaired if anastomoses were reinforced with BG. BG did not affect the anastomotic stricture rate for up to 3 months; nevertheless, intra-abdominal adhesions were increased.

Superconducting and normal-state anisotropy of the doped topological insulator Sr0.1Bi2Se3.

SrxBi2Se3 and the related compounds CuxBi2Se3 and NbxBi2Se3 have attracted considerable interest, as these materials may be realizations of unconventional topological superconductors. Superconductivity with Tc ~3 K in SrxBi2Se3 arises upon intercalation of Sr into the layered topological insulator Bi2Se3. Here we elucidate the anisotropy of the normal and superconducting state of Sr0.1Bi2Se3 with angular dependent magnetotransport and thermodynamic measurements. High resolution x-ray diffraction studies underline the high crystalline quality of the samples. We demonstrate that the normal state electronic and magnetic properties of Sr0.1Bi2Se3 are isotropic in the basal plane while we observe a large two-fold in-plane anisotropy of the upper critical field in the superconducting state. Our results support the recently proposed odd-parity nematic state characterized by a nodal gap of Eu symmetry in SrxBi2Se3.

Nanocalorimeter platform for in situ specific heat measurements and x-ray diffraction at low temperature.

Recent advances in electronics and nanofabrication have enabled membrane-based nanocalorimetry for measurements of the specific heat of microgram-sized samples. We have integrated a nanocalorimeter platform into a 4.5 T split-pair vertical-field magnet to allow for the simultaneous measurement of the specific heat and x-ray scattering in magnetic fields and at temperatures as low as 4 K. This multi-modal approach empowers researchers to directly correlate scattering experiments with insights from thermodynamic properties including structural, electronic, orbital, and magnetic phase transitions. The use of a nanocalorimeter sample platform enables numerous technical advantages: precise measurement and control of the sample temperature, quantification of beam heating effects, fast and precise positioning of the sample in the x-ray beam, and fast acquisition of x-ray scans over a wide temperature range without the need for time-consuming re-centering and re-alignment. Furthermore, on an YBa2Cu3O7-δ crystal and a copper foil, we demonstrate a novel approach to x-ray absorption spectroscopy by monitoring the change in sample temperature as a function of incident photon energy. Finally, we illustrate the new insights that can be gained from in situ structural and thermodynamic measurements by investigating the superheated state occurring at the first-order magneto-elastic phase transition of Fe2P, a material that is of interest for magnetocaloric applications.