Surface Modification of Lignite with Alkyl and Mixed Alkyl-Aryl Films Generated from an Aryl Diazonium Salt and Alkyl Halides: Experimental Results and Theoretical Analyses.

In search of new possible uses of cheap lignite from the Kosova Bassin, the surface of lignite powders is modified with alkyl or mixed alkyl-aryl layers. Modification is performed in aqueous acid solution containing an aryl diazonium salt and an alkyl halide compound in millimolar concentration, in the presence of potassium iodide as a reducing agent at equimolar concentration. Attachment of alkyl films substituted with carboxylic groups and aryl films with nitro or bis-trifluoromethyl groups is characterized by IRATR and XPS spectroscopy. The formation of a stable interface during the grafting reactions of alkyl and aryl moieties with lignite surface has been confirmed by theoretical calculations. Aryl diazonium salts once chemically or spontaneously reduced are a source of aryl radicals, able to attach chemically to the material surface or to react with alkyl halides by abstracting the halogen atom. If the aryl diazonium salts are unable to graft to the coal surface due to steric hindrance, they can, nevertheless, abstract an iodine or bromine atom to generate alkyl radicals that react with the material surface.

Dual-Mode Nanoprobes Based on Lanthanide Doped Fluoride Nanoparticles Functionalized by Aryl Diazonium Salts for Fluorescence and SERS Bioimaging.

The design of dual-mode fluorescence and Raman tags stimulates a growing interest in biomedical imaging and sensing applications as they offer the possibility to synergistically combine the versatility and velocity of fluorescence imaging with the specificity of Raman spectroscopy. Although lanthanide-doped fluoride nanoparticles (NPs) are among the most studied fluorescent nanoprobes, their use for the development of bimodal fluorescent-Raman probes has never been reported yet, to the best of the authors knowledge, probably due to the difficulty to functionalize them with Raman reporter groups. This gap is filled herein by proposing a fast and straightforward approach based on aryl diazonium salt chemistry to functionalize Eu3+ or Tb3+ doped CaF2 and LaF3 NPs by Raman scatters. The resulting surface-enhanced Raman spectroscopy (SERS)-encoded lanthanide-doped fluoride NPs retain their fluorescence labeling capacity and display efficient SERS activity for cell bioimaging. The potential of this new generation of bimodal nanoprobes is assessed through cell viability assays and intracellular fluorescence and Raman imaging, opening up unprecedented opportunities for biomedical applications.

Selective Nsp2 - and Csp2 - Photografting of Au-Surface by Aryldiazonium Salts and Arylazo Sulfonates.

Arylazo sulfonates (Ar-N=N-SO3 Na) have been found to undergo photografting on gold surface through both Au-Nsp2 - and Au-Csp2 - bond formation. The functionalized materials have been fully characterized by infrared reflection absorption spectroscopy (IRRAS), Raman, XPS, DFT calculations and UV-Vis absorption spectroscopy. These methods permit to evidence aromatic substituents (IRRAS), the Au-N=N signature (Raman and XPS spectroscopy), and the bond dissociation energy values of the two linkages (DFT calculation). The grafting proceeds through two competitive paths, namely a stepwise reaction involving an aryl radical (for the formation of the Au-Ar bonds) and a concerted reaction on the surface of gold (for Au-N=N-Ar bond formation). The occurrence of an aryl radical upon irradiation has been fully evidenced by EPR spectroscopy. Finally, E/Z photoisomerisation of the N=N bonds present on prepared few layer films has been observed by means of UV-Vis absorption spectroscopy.

Can the Realization of an External Wirsungostomy be an Option for High-Risk Pancreatic Anastomosis After Pancreaticoduodenectomy?

BACKGROUND: Clinically relevant postoperative pancreatic fistula (POPF) occurs in 15-20% of patients after pancreaticoduodenectomy (PD) and reintervention in the setting of Grade C POPF remains associated with a mortality rate of up to 25%. In patients at high risk of POPF, PD with external wirsungostomy (EW) could be a safe alternative that avoids pancreatico-enteric anastomosis while preserving the remnant pancreas. METHODS: Of the 155 consecutive patients who underwent PD from November 2015 to December 2020, 10 patients were managed using an EW, all with a fistula risk score (FRS) ≥ 7 and BMI ≥30 kg/m2, and/or major associated abdominal surgery. The pancreatic duct was cannulated with a polyethylene tube to allow good external drainage of the pancreatic fluid. We retrospectively analyzed postoperative complications and endocrine and exocrine insufficiencies. RESULTS: The median alternative FRS was 36.9% [22.1-45.2]. There was no postoperative death. The 90-day overall severe complication (grade ≥3) rate was 30% (n = 3 patients), no patient required reoperation, and 2 hospital readmissions occurred. 3 patients experienced Grade B POPF (30%), managed using image-guided drainage for 2 patients. The external pancreatic drain was removed after a median drainage time of 75 days [63-80]. Two patients presented with late symptoms (> 6 months) warranting interventional management (pancreaticojejunostomy and transgastric drainage). Six patients experienced significant weight loss (> 2 kg) 3 months after surgery. One year after surgery, 4 patients still complained of diarrhea and were treated with transit-delaying drugs. One patient presented new-onset diabetes one year after surgery, and 1 of the 4 patients with preexisting diabetes experienced worsening disease. CONCLUSION: EW after PD might be a solution to reduce post-operative mortality following PD in high-risk patients.

Methodological and ethical quality of surgical trials from 2016 to 2020.

PURPOSE: Randomized controlled trials (RCTs) are the gold standard tool used to evaluate therapeutic interventions. The published results showed that progress still needs to be made not only from a methodological point of view but also from an ethical point of view. The aim of this study was to evaluate the methodological and ethical qualities of randomized clinical trials in surgery over the last few years. METHODS: All of the articles chosen for review reported on randomized controlled surgical trials and were published in 10 international journals between 2016 and 2020. Eligible studies were identified, selected, and then evaluated based on a broad set of predetermined criteria. Methodological quality was evaluated using the Jadad scale, and ethical quality was evaluated using the Berdeu score. RESULTS: The methodological quality score (Jadad scale) ranged from 5 to 13, with a mean of 10.0 ± 1.54. The methodological quality was insufficient (score ≤ 9) for 162 trials (31.2%). The ethical quality score ranged from 0.25 to 1, with a mean of 0.8 ± 0.11. Fifty-two articles (10%) did not state that informed consent was requested from the participants, and 21 articles (4%) did not report either research ethics committee or institutional committee protocol approval. CONCLUSION: The randomized clinical surgical trials analyzed showed that they had satisfactory methods in only 70% of the cases and that they had respected the fundamental ethical principles in 90% of the cases. However, less than 8% of the studies reported planned interim analysis, prospectively defined stopping rules, and independent monitoring committee.

Role of protective stoma after primary anastomosis for generalized peritonitis due to perforated diverticulitis-DIVERTI 2 (a prospective multicenter randomized trial): rationale and design (nct04604730).

BACKGROUND: Traditionally, patients with peritonitis Hinchey III and IV due to perforated diverticulitis were treated with Hartmann's procedure. In the past decade, resection and primary anastomosis have gained popularity over Hartmann's procedure and recent guidelines recommend Hartmann's procedure in two situations only: critically ill patients and in selected patients with multiple comorbidity (at high risk of complications). The protective stoma (PS) is recommended after resection with primary anastomosis, however its interest has never been studied. The aim of this trial is to define the role of systematic PS after resection and primary anastomosis for peritonitis Hinchey III and IV due to perforated diverticulitis. METHODS/DESIGN: This DIVERTI 2 trial is a multicenter, randomized, controlled, superiority trial comparing resection and primary anastomosis with (control group) or without (experimental group) PS in patients with peritonitis Hinchey III and IV due to perforated diverticulitis. Primary endpoint is the overall 1 year morbidity according to the Clavien-Dindo classification of surgical complications. All complications occurring during hospitalization will be collected. Late complications occurring after hospitalization will be collected during follow-up. In order to obtain 80% power for a difference given by respective main probabilities of 67% and 47% in the protective stoma and no protective stoma groups respectively, with a two-sided type I error of 5%, 96 patients will have to be included in each group, hence 192 patients overall. Expecting a 5% rate of patients not assessable for the primary end point (lost to follow-up), 204 patients will be enrolled. Secondary endpoints are postoperative mortality, unplanned reinterventions, incisional surgical site infection (SSI), organ/space SSI, wound disruption, anastomotic leak, operating time, length of hospital stay, stoma at 1 year after initial surgery, quality of life, costs and quality-adjusted life years (QALYs). DISCUSSION: The DIVERTI 2 trial is a prospective, multicenter, randomized, study to define the best strategy between PS and no PS in resection and primary anastomosis for patients presenting with peritonitis due to perforated diverticulitis. TRIAL REGISTRATION: ClinicalTrial.gov: NCT04604730 date of registration October 27, 2020. https://clinicaltrials.gov/ct2/show/NCT04604730?recrs=a&cond=Diverticulitis&draw=2&rank=12 .

Examining the Role of Aryldiazonium Salts in Surface Electroinitiated Polymerization.

Historically, the irreversible reduction of aryldiazonium salts has provided a reliable method to modify surfaces, demonstrating a catalogue of suitable diazonium salts for targeted applications. This work expands the knowledge of diazonium salt chemistry to participate in surface electroinitiated emulsion polymerization (SEEP). The influence of concentration, electronic effects, and steric hindrance/regiochemistry of the diazonium salt initiator on the production of polymeric films is examined. The objective of this work is to determine if a polymer film can be tailored, controlling the thickness, density, and surface homogeneity using specific diazonium chemistry. The data presented herein demonstrate a significant difference in polymer films that can be achieved when selecting a variety of diazonium salts and vinylic monomers. A clear trend aligns with the electron-rich diazonium salt substitution providing the thickest films (up to 70.9 ± 17.8 nm) with increasing diazonium concentration and electron-withdrawing substitution achieving optimal homogeneity for the surface of the film at a 5 mM diazonium concentration.

SERS tags derived from silver nanoparticles and aryl diazonium salts for cell Raman imaging.

The surface functionalization of silver nanoparticles (NPs) by Raman reporters has stimulated a wide interest in recent years for the design of Surface-Enhanced Raman Spectroscopy (SERS) labels. However, silver NPs are prone to oxidation and aggregation, which strongly limits their applications. The design of stable SERS tags based on Ag NPs still represents a major challenge for Raman bioimaging. We address this issue herein by taking advantage of aryl diazonium salt chemistry to obtain stable Ag NPs functionalized by multifunctional polyaryl layers bearing different Raman reporters (-NO2, -CN, -CCH). The resulting SERS-encoded Ag NPs were characterized by UV-vis absorption, transmission electron microscopy (TEM) and SERS. The formation of multilayers at the surface of Ag NPs gives access to new spectrally distinguishable SERS codes thus broadening the library of available Raman tags. Proof-of-concept Raman imaging experiments were performed on cancer cells (HeLa) after NP uptake, highlighting the large potentials of diazonium salt chemistry to design Ag NPs-based SERS labels for Raman bioimaging.

Electrografting and Langmuir-Blodgett: Covalently Bound Nanometer-Thick Ordered Films on Graphite.

We present two different molecular organizations obtained from octadecylamine (ODA) molecules on a highly oriented pyrolytic graphite (HOPG) surface: (i) self-organized physisorbed ODA molecules lying flat on the surface and (ii) a strongly electrografted compact crystalline monolayer of ODA molecules standing up on the surface. This new structure is obtained by combining the Langmuir-Blodgett transfer of an ODA Langmuir film onto HOPG with oxidative electrografting. The presence of an organic film on HOPG is characterized by attenuated total reflectance-infrared spectroscopy and Raman spectroscopy, while atomic force microscopy and scanning tunneling microscopy allow the observation of the two molecular organizations with adsorbed molecules lying flat on HOPG or strongly grafted in an upright position on the HOPG surface. Interestingly, the second molecular organization preserves a hexagonal symmetry and its lattice parameters are intermediate between those of ODA Langmuir films and that of the HOPG underlying surface. The functionalization of surfaces with organic films is a major issue in the design of sensors with biomedical applications or organic electronics and energy storage devices and these structures may find applications in these fields.

Surface functionalization of nanomaterials by aryl diazonium salts for biomedical sciences.

Nanoparticles (NPs) can be prepared by simple reactions and methods from a number of materials. Their small size opens up a number of applications in different fields, among which biomedicine, including: i) drug delivery, ii) biosensors, iii) bioimaging, iv) antibacterial activity. To be able to perform such tasks, NPs must be modified with a variety of functional molecules, such as drugs, targeting groups, chemical tags or antibacterial agents, and must also be prevented from aggregation. The attachment must be stable to resist during the transportation to the targeted location. Diazonium salts, which have been widely used for coupling applications and surface modification, fulfil such criteria. Moreover, they are simple to prepare and can be easily substituted with a large number of organic groups. This review describes the use of these compounds in nanomedicine with a focus on the construction of nanohybrids derived from metal, oxide and carbon-based NPs as well as viruses.

Total Pelvic Exenteration, Cytoreductive Surgery, and Hyperthermic Intraperitoneal Chemotherapy for Rectal Cancer with Associate Peritoneal Metastases: Surgical Strategies to Optimize Safety.

BACKGROUND: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is a curative treatment option for patients with peritoneal carcinomatosis. Total pelvic exenteration (TPE) is an established treatment option for locally advanced pelvic malignancy. These two procedures have high mortality and morbidity, and therefore, their combination is not currently recommended. Herein, we reported our experience on TPE associated with CRS/HIPEC with a critical analysis for rectal cancer with associate peritoneal metastases. METHODS: From March 2006 to August 2020, 319 patients underwent a CRS/HIPEC in our hospital. Among them, 16 (12 men and four women) underwent an associated TPE. The primary endpoints were perioperative morbidity and mortality. RESULTS: There was locally recurrent rectal cancer in nine cases, six locally advanced primary rectal cancer, and a recurrent appendiceal adenocarcinoma. The median Peritoneal Cancer Index (PCI) was 8. (4-16). Mean duration of the surgical procedure was 596 min (420-840). Complete cytoreduction (CC0) was achieved in all patients, while clear resection (R0) margins on the resected pelvic organs were achieved in 81.2% of cases. The median hospital stay was 46 days (26-129), and nine patients (56.2%) experienced severe complications (grade III to V) that led to death in two cases (12.5%). The total reoperation rate for patients was 6/16 (37.5%) and 3/16 (18.75%) with percutaneous radiological-guided drainage. CONCLUSIONS: In summary, TPE/extended TPE (ETPE) associated with CRS/HIPEC may be a reasonable procedure in selected patients at expert centers. Pelvic involvement should not be considered a definitive contraindication for CRS/HIPEC in patients with resectable peritoneal surface diseases if a R0 resection could be achieved on all sites. However, the morbidity and the mortality are high with this combination of treatment, and further research is needed to assess the oncologic benefit and quality of life before such a radical approach can be recommended.

Expanding the Scope of Surface Grafted Polymers Using Electroinitiated Polymerization.

The ability to rapidly modify the surface of materials is a powerful means of tailoring interfaces and interphases for a variety of applications. In this work, we demonstrate the extensive scope of an electrochemically mediated surface modification technique, able to install a range of surface grafted polymers of varying polarity and functionality. The irreversible reduction of aryldiazonium salts initiates polymer growth and provides a "priming layer" for the polymers to attach to, covalently anchoring them to the surface. We show the broad applicability of this technique through polymerization of 19 acrylate monomers, as well as a noncarbonyl bearing monomer species, styrene. Surface bound films were characterized using FT-IR, ellipsometry, and water contact angle.

Simultaneous Photografting of Two Organic Groups on a Gold Surface by using Arylazo Sulfones as Single Precursors.

Arylazo sulfones have been exploited as photoactivatable substrates for the simultaneous photografting of both aryl and methanesulfonyl groups on a gold surface. The obtained samples have been characterized by different spectroscopic techniques including ellipsometry and electrochemistry, infrared reflection absorption, surface-enhanced Raman spectroscopy, XPS, and AFM. Grafting occurs through a simple N-S cleavage and not, as usually observed with aromatic precursors, by electron transfer.

Grafting of Diazonium Salts on Surfaces: Application to Biosensors.

This review is divided into two parts; the first one summarizes the main features of surface modification by diazonium salts with a focus on most recent advances, while the second part deals with diazonium-based biosensors including small molecules of biological interest, proteins, and nucleic acids.

Fiber with Butterfly Wings: Creating Colored Carbon Fibers with Increased Strength, Adhesion, and Reversible Malleability.

Colored and color-changing materials are central to perception and interaction in nature and have been exploited in an array of modern technologies such as sensors, visual displays, and smart materials. Attempts to introduce color into carbon fiber materials have been limited by deleterious impacts on fiber properties, and the extension of colored fibers toward "smart composites" remains in its infancy. We present carbon fibers incorporating structural color, similar to that observed on the surface of soap bubbles and various insects and birds, by modifying the fiber surface through in situ polymerization grafting. When dry, the treated fibers exhibit a striking blue color, but when exposed to a volatile solvent, a cascade of colors across the visible light region is observed as the film first swells and then shrinks as the solvent evaporates. The treated fibers not only possess a unique color and color-changing ability but also can be reversibly formed into complex shapes and bear significant loads even without being encased in a supporting polymer. The tensile strength of treated fibers shows a statistically significant increase (+12%), and evaluation of the fiber-to-matrix adhesion of these polymers to an epoxy resin shows more than 300% improvement over control fibers. This approach creates a new platform for the multifaceted advance of smart composites.

Alkyl-Modified Gold Surfaces: Characterization of the Au-C Bond.

The surface of gold can be modified with alkyl groups through a radical crossover reaction involving alkyliodides or bromides in the presence of a sterically hindered diazonium salt. In this paper, we characterize the Au-C(alkyl) bond by surface-enhanced Raman spectroscopy (SERS); the corresponding peak appears at 387 cm-1 close to the value obtained by theoretical modeling. The Au-C(alkyl) bond energy is also calculated, it reaches -36.9 kcal mol-1 similar to that of an Au-S-alkyl bond but also of an Au-C(aryl) bond. In agreement with the similar energies of Au-C(alkyl) and Au-S-(alkyl), we demonstrate experimentally that these groups can be exchanged on the surface of gold.

Diazonium salt chemistry for the design of nano-textured anti-icing surfaces.

Aryl diazonium salts have emerged as a new generation of robust surface modifiers for a wide range of applications. However, their use for creating anti-icing surfaces has never been investigated so far. We fill this gap by modifying nano-textured copper surfaces with aryl diazonium salts, bearing low surface energy end groups, leading to efficient anti-icing properties.

Surface functionalisation of polymers.

Many applications of polymers require the functionalisation of their surface for use in sensors, composite materials, membranes, microfluidic and biomedical devices and many others. Such surface modifications endow the surface with new properties independent of those of the bulk polymer. This tutorial review describes the different methods, based on very diverse principles, that are available to perform this surface functionalisation, including plasma and UV irradiation, atomic layer deposition, electrochemistry, oxidation, reduction, hydrolysis, the use of radicals and grafting "on" or "from" polymers. The principles of the different methods are briefly described and many examples are given to highlight the possibilities of the methods and the possible applications. A section is devoted to the surface modification of polymeric nanoparticles.