Has the non-resection rate decreased during the last two decades among patients undergoing surgical exploration for pancreatic adenocarcinoma?

PURPOSE: To determine if improvement in imaging reduces the non-resection rate (NRR) among patients with pancreatic ductal adenocarcinoma (PDAC). METHODS: From 2000 to 2019, 751 consecutive patients with PDAC were considered eligible for a intention-to-treat pancreatectomy and entered the operating room. In April 2011, our institution acquired a dual energy spectral computed tomography (CT) scanner and liver diffusion weighted magnetic resonance imaging (DW-MRI) was included in the imaging workup. We consequently considered 2 periods of inclusion: period #1 (February 2000-March 2011) and period #2 (April 2011-August 2019). RESULTS: All patients underwent a preoperative CT scan with a median delay to surgery of 18 days. Liver DW-MRI was performed among 407 patients (54%). Median delay between CT and surgery decreased (21 days to 16 days, P < .01), and liver DW-MRI was significantly most prescribed during period #2 (14% vs 75%, P < .01). According to the intraoperative findings, the overall NRR was 24.5%, and remained stable over the two periods (25% vs 24%, respectively). While vascular invasion, liver metastasis, and carcinomatosis rates remained stable, para-aortic lymph nodes invasion rate (0.4% vs 4.6%; P < 0.001) significantly increased over the 2 periods. The mean size of the bigger extra pancreatic tumor significantly decrease (7.9 mm vs 6.4 mm (P < .01), respectively) when the resection was not done. In multivariate analysis, CA 19-9 < 500 U/mL (P < .01), and liver DW-MRI prescription (P < .01) favoured the resection. CONCLUSIONS: Due to changes in our therapeutic strategies, the NRR did not decrease during two decades despite imaging improvement.

Intra-versus extracorporeal anastomosis in laparoscopic right colectomy: a meta-analysis of 3699 patients.

BACKGROUND: Laparoscopic right colectomy (LRC) has become a gold standard. However, a major current concern is still whether anastomosis should be performed extracorporeally or entirely laparoscopically. This meta-analysis assesses and compares peri- and postoperative outcomes of intracorporeal anastomosis (IA) versus extracorporeal anastomosis (EA) in LRC. METHODS: The research used the PubMed, Embase and Cochrane databases for studies comparing IA with EA during LRC. Our main endpoint was parietal abscess. Secondary endpoints were 30-day morbidity, mortality, time to onset of gas and stools, length of stay, number of lymph nodes removed and postoperative incisional hernia rates. The MINORS criteria were used to evaluate the quality of the studies examined. RESULTS: Twenty-four articles comprising 3699 patients, published between 2004 and 2020, were included in this meta-analysis. After sensitivity analysis, IA was associated with a decrease in parietal abscesses (OR 0.526, IC 0.333-0.832, p = 0.006). CONCLUSION: This meta-analysis finds that IA allows a decrease in parietal abscesses and time to first gas and stools, surgical repair and length of stay, with similar overall complications.

Spin-Orbit-Enhanced Robustness of Supercurrent in Graphene/WS_{2} Josephson Junctions.

We demonstrate the enhanced robustness of the supercurrent through graphene-based Josephson junctions in which strong spin-orbit interactions (SOIs) are induced. We compare the persistence of a supercurrent at high out-of-plane magnetic fields between Josephson junctions with graphene on hexagonal boron-nitride and graphene on WS_{2}, where strong SOIs are induced via the proximity effect. We find that in the shortest junctions both systems display signatures of induced superconductivity, characterized by a suppressed differential resistance at a low current, in magnetic fields up to 1 T. In longer junctions, however, only graphene on WS_{2} exhibits induced superconductivity features in such high magnetic fields, and they even persist up to 7 T. We argue that these robust superconducting signatures arise from quasiballistic edge states stabilized by the strong SOIs induced in graphene by WS_{2}.

Strong Anisotropic Spin-Orbit Interaction Induced in Graphene by Monolayer WS_{2}.

We demonstrate strong anisotropic spin-orbit interaction (SOI) in graphene induced by monolayer WS_{2}. Direct comparison between graphene-monolayer WS_{2} and graphene-bulk WS_{2} systems in magnetotransport measurements reveals that monolayer transition metal dichalcogenide can induce much stronger SOI than bulk. Detailed theoretical analysis of the weak antilocalization curves gives an estimated spin-orbit energy (E_{so}) higher than 10 meV. The symmetry of the induced SOI is also discussed, and the dominant z→-z symmetric SOI can only explain the experimental results. Spin relaxation by the Elliot-Yafet mechanism and anomalous resistance increase with temperature close to the Dirac point indicates Kane-Mele SOI induced in graphene.

Free surfaces recast superconductivity in few-monolayer MgB2: Combined first-principles and ARPES demonstration.

Two-dimensional materials are known to harbour properties very different from those of their bulk counterparts. Recent years have seen the rise of atomically thin superconductors, with a caveat that superconductivity is strongly depleted unless enhanced by specific substrates, intercalants or adatoms. Surprisingly, the role in superconductivity of electronic states originating from simple free surfaces of two-dimensional materials has remained elusive to date. Here, based on first-principles calculations, anisotropic Eliashberg theory, and angle-resolved photoemission spectroscopy (ARPES), we show that surface states in few-monolayer MgB2 make a major contribution to the superconducting gap spectrum and density of states, clearly distinct from the widely known, bulk-like σ- and π-gaps. As a proof of principle, we predict and measure the gap opening on the magnesium-based surface band up to a critical temperature as high as ~30 K for merely six monolayers thick MgB2. These findings establish free surfaces as an unavoidable ingredient in understanding and further tailoring of superconductivity in atomically thin materials.

Room-temperature growth of colloidal Bi2Te3 nanosheets.

In this work, we report the colloidal synthesis of Bi2Te3 nanosheets with controlled thickness, morphology and crystallinity at temperatures as low as 20 °C. Grown at room temperature, Bi2Te3 exhibits two-dimensional morphology with thickness of 4 nm and lateral size of 200 nm. Upon increasing the temperature to 170 °C, the nanosheets demonstrate increased thickness of 16 nm and lateral dimensions of 600 nm where polycrystalline nanosheets (20 °C) are replaced by single crystal platelets (170 °C). Rapid synthesis of the material at moderately low temperatures with controllable morphology, crystallinity and consequently electrical and thermal properties can pave the way toward its large-scale production for practical applications.

Conflict of interests for radiation oncologists: Harnessing disclosures from policy to reality.

PURPOSE: An increasing attention is being paid to disclosures of conflicts of interests in the field of oncology. The purpose of this study was to examine how radiation oncologists report their conflicts of interests with pharmaceutical or technology industries. MATERIALS AND METHODS: We collected the data of conflicts of interests disclosures in the abstract books from the annual 2012 and 2013 meetings of the American Society for Radiation Oncology (ASTRO) in Miami (FL, USA), and in Atlanta (GA, USA), respectively. Geographic origins of abstracts as well other factors were examined. RESULTS: We identified a total of 4219 abstracts published in the past two years. The total number of involved authors was of 28,283. All of the published abstracts had conflicts of interests disclosures. Amongst them, 563 abstracts (13.4%) reported at least one potential conflict of interests, in which 1264 (4.5%) declared a potential conflict of interests in their disclosures. Geographic distribution of abstracts with financial relationship was as following: 67.9%, 15.5%, 7.7% and 7.7% for USA, Europe, Asia/Pacifica, and Canada, respectively. Abstracts with conflict of interest originated from North America in 75.6% of cases. USA distribution was 70.6% and 29.4% for Eastern and Western, respectively. CONCLUSIONS: The proportion of physicians declaring financial conflicts of interests remains extremely low, whichever geographic area authors are from. In comparison to the rest of the world, the US proved itself better at declaring potential links. Changes in medical culture and education could represent a significant step to improve the process of revealing conflicts of interest in medical journal as well as in international meetings.

UV-Enhanced Sacrificial Layer Stabilised Graphene Oxide Hollow Fibre Membranes for Nanofiltration.

Graphene oxide (GO) membranes have demonstrated great potential in gas separation and liquid filtration. For upscale applications, GO membranes in a hollow fibre geometry are of particular interest due to the high-efficiency and easy-assembly features at module level. However, GO membranes were found unstable in dry state on ceramic hollow fibre substrates, mainly due to the drying-related shrinkage, which has limited the applications and post-treatments of GO membranes. We demonstrate here that GO hollow fibre membranes can be stabilised by using a porous poly(methyl methacrylate) (PMMA) sacrificial layer, which creates a space between the hollow fibre substrate and the GO membrane thus allowing stress-free shrinkage. Defect-free GO hollow fibre membrane was successfully determined and the membrane was stable in a long term (1200 hours) gas-tight stability test. Post-treatment of the GO membranes with UV light was also successfully accomplished in air, which induced the creation of controlled microstructural defects in the membrane and increased the roughness factor of the membrane surface. The permeability of the UV-treated GO membranes was greatly enhanced from 0.07 to 2.8 L m(-2) h(-1) bar(-1) for water, and 0.14 to 7.5 L m(-2) h(-1) bar(-1) for acetone, with an unchanged low molecular weight cut off (~250 Da).

Microwave surface impedance measurements on reduced graphene oxide.

Here we report a non-contact method for microwave surface impedance measurements of reduced graphene oxide samples using a high Q dielectric resonator perturbation technique, with the aim of studying the water content of graphene oxide flakes. Measurements are made before, during and after heating and cooling cycles. We have modelled plane wave propagation of microwaves perpendicular to the surface of graphene on quartz substrates, capacitively coupled to a dielectric resonator. Analytical solutions are derived for both changes in resonant frequency and microwave loss for a range of water layer thicknesses. In this way we have measured the presence of adsorbed water layers in reduced graphene oxide films. The water can be removed by low temperature annealing on both single and multilayer samples. The results indicate that water is intercalated between the layers in a multilayer sample, rather than only being adsorbed on the outer surfaces, and it can be released by applying a mild heating.

Unusual infrared-absorption mechanism in thermally reduced graphene oxide.

Infrared absorption of atomic and molecular vibrations in solids can be affected by electronic contributions through non-adiabatic interactions, such as the Fano effect. Typically, the infrared-absorption lineshapes are modified, or infrared-forbidden modes are detectable as a modulation of the electronic absorption. In contrast to such known phenomena, we report here the observation of a giant-infrared-absorption band in reduced graphene oxide, arising from the coupling of electronic states to the asymmetric stretch mode of a yet-unreported structure, consisting of oxygen atoms aggregated at the edges of defects. Free electrons are induced by the displacement of the oxygen atoms, leading to a strong infrared absorption that is in phase with the phonon mode. This new phenomenon is only possible when all other oxygen-containing chemical species, including hydroxyl, carboxyl, epoxide and ketonic functional groups, are removed from the region adjacent to the edges, that is, clean graphene patches are present.

Controlling the catalyst during carbon nanotube growth.

We have recently been able to grow single-walled carbon nanotubes by purely thermal chemical vapour deposition (CVD) at temperatures as low as 400 degrees C. This has been achieved by separating the catalyst pre-treatment step from the growth step. In the pre-treatment step, a thin film catalyst is re-arranged into a series of nano-droplets, which are then the active catalysts. Both steps have been studied by in-situ environmental transmission electron microscopy and X-ray photoemission spectroscopy. We have also studied the catalyst yield, the weight of nanotubes grown per weight of transition metal catalyst. Using very thin layers of Fe on Al2O3 support in a remote plasma-assisted CVD, we have achieved yields of order 100,000. This may be due to control of catalyst poisoning by ensuring an etching path.