High-resolution deposition of conductive and insulating materials at micrometer scale on complex substrates.

Additive manufacturing transforms the landscape of modern microelectronics. Recent years have witnessed significant progress in the fabrication of 2D planar structures and free-standing 3D architectures. In this work, we present a much-needed intermediary approach: we introduce the Ultra-Precise Deposition (UPD) technology, a versatile platform for material deposition at micrometer scale on complex substrates. The versality of this approach is related to three aspects: material to be deposited (conductive or insulating), shape of the printed structures (lines, dots, arbitrary shapes), as well as type and shape of the substrate (rigid, flexible, hydrophilic, hydrophobic, substrates with pre-existing features). The process is based on the direct, maskless deposition of high-viscosity materials using narrow printing nozzles with the internal diameter in the range from 0.5 to 10 µm. For conductive structures we developed highly concentrated non-Newtonian pastes based on silver, copper, or gold nanoparticles. In this case, the feature size of the printed structures is in the range from 1 to 10 µm and their electrical conductivity is up to 40% of the bulk value, which is the record conductivity for metallic structures printed with spatial resolution below 10 µm. This result is the effect of the synergy between the printing process itself, formulation of the paste, and the proper sintering of the printed structures. We demonstrate a pathway to print such fine structures on complex substrates. We argue that this versatile and stable process paves the way for a widespread use of additive manufacturing for microfabrication.

Anatomical fixation of tibial intercondylar eminence fractures in children using a threaded pin with an adjustable lock.

INTRODUCTION: Tibial intercondylar eminence fractures are a rare pathology causing anterior laxity of the knee, which requires anatomical reduction and a stable osteosynthesis. The aim of this study was to present the clinical results of reinsertion in anatomical position of these fractures, in the paediatric population, using a threaded pin with an adjustable lock. HYPOTHESIS: Our hypothesis was that the clinical results would be satisfactory and comparable to the literature. METHOD: This retrospective, monocentric study involved 34 consecutive patients with tibial intercondylar eminence fractures, divided into 55.9% with type 2, 35.2% with type 3, 8.8% with type 4 according to Meyers & McKeever, operated on between March 1999 and March 2018. Assessments were performed at a minimum follow-up of 1-year and included the Lysholm, subjective International Knee Documentation Committee (IKDC) and Tegner activity scores, and the measurement of anterior knee laxity by the KT1000. RESULTS: At the average follow-up of 8.8 years, 7 patients were lost to follow-up, 2 required anterior cruciate ligament reconstruction. Pathological residual laxity was present in 25% of cases and instability in 16%. The average Lysholm score was 93.1±9.8, the average subjective IKDC was 93.8±6.4 and the average Tegner score was 5.6±1.5. The average anterior laxity of the knee was 0.7±2.0mm. CONCLUSION: The anatomical reinsertion using a threaded pin with an adjustable lock for tibial intercondylar eminence fractures in a paediatric population provides good functional results and is comparable to the data in the literature. LEVEL OF EVIDENCE: IV; retrospective.

Functional outcome following closed reduction and percutaneous osteosynthesis of distal tibia articular fractures in children.

Closed reduction and percutaneous osteosynthesis is an alternative to the open procedure for articular fractures of distal tibia of children. 38 patients were retrospectively reviewed. The measured parameters were : the score of Gleizes and the discrepancies between preoperative radiographic and CT scan measurements and postoperative radiographs. A significant correlation was found between the gap and the step-off in preoperative radiographic and CT scan. A significant decrease of the gap and step-off displacement was noticed after surgery. The Gleizes scoring showed 35 good results, 2 average results and 1 poor result. Percutaneous fixation of ankle articular fractures in children is a simple and effective treatment giving similar results to open techniques while minimizing the risk of joint stiffness and healing complications. Growth complications are comparable with both techniques.

Outpatient paediatric arthroscopy: A retrospective study in 216 Patients.

BACKGROUND: Outpatient surgery is now widely performed in adults but remains rarely used for paediatric orthopaedic procedures. As with adult surgery, both the arthroscopic equipment and anaesthesia techniques have improved over the last few years. Arthroscopy is particularly well advanced at the knee but can also be used at other joints (hip, ankle, elbow, shoulder). The primary objective of this study was to evaluate the feasibility of outpatient paediatric arthroscopy. HYPOTHESIS: Arthroscopic surgery can be performed in children on an outpatient basis provided an appropriate care programme is applied. MATERIALS AND METHODS: This single-centre retrospective study included 216 patients aged 3.8 to 18 years who underwent outpatient arthroscopy (knee, n=170; ankle, n=22; elbow, n=12; shoulder, n=6; and hip, n=6). The decision to perform the procedure on an outpatient basis was made with the patient during the surgeon visit then confirmed during the anaesthesiologist visit. The main outcome measure was failure of outpatient arthroscopy defined as a need for standard inpatient admission. The secondary outcome measures were pain or sleep disturbances on the day after the procedure (as assessed during a telephone call), a need to see a physician during the first week after the procedure, and patient satisfaction. RESULTS: Of the 216 patients, 9 required overnight admission (4 because of vomiting, 4 because of pain, and 1 because of a malaise) and 2 patients were admitted elsewhere for postoperative pain then discharged within 24hours. Of the 160 patients who could be contacted on the day after the procedure, 141 (88%) said they had had a good night and 141 (88%) that they had little or no pain. Over 95% of patients were satisfied with their outpatient management. DISCUSSION: As with adults, arthroscopic surgery is an ideal indication for outpatient care in paediatric patients. Outpatient arthroscopic surgery is already widely used at the knee and is also suitable for other joints in the paediatric population. LEVEL OF EVIDENCE: IV, retrospective study.

Probing the Surface of a Laccase for Clues towards the Design of Chemo-Enzymatic Catalysts.

Systems featuring a multi-copper oxidase associated with transition-metal complexes can be used to perform oxidation reactions in mild conditions. Here, a strategy is presented for achieving a controlled orientation of a ruthenium-polypyridyl graft at the surface of a fungal laccase. Laccase variants are engineered with unique surface-accessible lysine residues. Distinct ruthenium-polypyridyl-modified laccases are obtained by the reductive alkylation of lysine residues precisely located relative to the T1 copper centre of the enzyme. In none of these hybrids does the presence of the graft compromise the catalytic efficiency of the enzyme on the substrate 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid). Furthermore, the efficiency of the hybrids in olefin oxidation coupled to the light-driven reduction of O2 is highly dependent on the location of the graft at the enzyme surface. Simulated RuII -CuII electron coupling values and distances fit well the observed reactivity and could be used to guide future hybrid designs.

Visible-Light-Driven Oxidation of Organic Substrates with Dioxygen Mediated by a [Ru(bpy)3 ](2+) /Laccase System.

Oxidation reactions are highly important chemical transformations that still require harsh reaction conditions and stoichiometric amounts of chemical oxidants that are often toxic. To circumvent these issues, olefins oxidation is achieved in mild conditions upon irradiation of an aqueous solution of the complex [Ru(bpy)3 ](2+) and the enzyme laccase. Epoxide formation is coupled to the light-driven reduction of O2 by [Ru(bpy)3 ](2+) /laccase system. The reactivity can be explained by dioxygen acting both as an oxidative agent and as renewable electron acceptor, avoiding the use of a sacrificial electron acceptor.

Laccases as palladium oxidases.

The first example of a coupled catalytic system involving an enzyme and a palladium(ii) catalyst competent for the aerobic oxidation of alcohol in mild conditions is described. In the absence of dioxygen, the fungal laccase LAC3 is reduced by a palladium(0) species as evidenced by the UV/VIS and ESR spectra of the enzyme. During the oxidation of veratryl alcohol performed in water, at room temperature and atmospheric pressure, LAC3 regenerates the palladium catalyst, is reduced and catalyzes the four-electron reduction of dioxygen into water with no loss of enzyme activity. The association of a laccase with a water-soluble palladium complex results in a 7-fold increase in the catalytic efficiency of the complex. This is the first step in the design of a family of renewable palladium catalysts for aerobic oxidation.