On the Electrochemical Growth of a Crystalline p-n Junction From Aqueous Solutions.

Our society largely relies on inorganic semiconductor devices which are, so far, fabricated using expensive and complex processes requiring ultra-high vacuum equipment. Here we report on the possibility of growing a p-n junction taking advantage of electrochemical processes based on the use of aqueous solutions. The growth of the junction has been carried out using the Electrochemical Atomic Layer Deposition (E-ALD) technique, which allowed to sequentially deposit two different semiconductors, CdS and Cu2S, on an Ag(111) substrate, in a single procedure. The growth process was monitored in situ by Surface X-Ray Diffraction (SXRD) and resulted in the fabrication of a thin double-layer structure with a high degree of crystallographic order and a well-defined interface. The high-performance electrical characteristics of the device were analysed ex-situ and show the characteristic feature of a diode.

Introducing the new concept of a chiral-polaron giant-IRAV signature, optical-active giant-response in vibrational circular dichroism.

Polycyclic aromatic hydrocarbons (PAHs) are a class of compounds of primary importance in the field of organic semiconductors, with applications in both organic electronics and photovoltaics. This paper delves into two strictly related topics. First, the theoretical rationalization of the physical factors underlying the emergence of the polaron "giant-response infrared active vibrations (IRAVs)" signature in positively charged PAHs. Results are presented concerning the tight comparison between the experimental results and theoretical results obtained within different DFT paradigms (BLYP, B3LYP, CAM-B3LYP and LC-BLYP) and the pure Hartree-Fock Hamiltonian. This allowed the rationalization of the emergence of the giant IRAV response as essentially propelled by long-range electronic interactions. Moreover, the role of vibrational modes and molecular dimensions (topology) is addressed. Second, the analysis is extended to chiral [4]helicene. This allows the introduction of a new concept yet to be explored experimentally: the chiral-polaron giant-IRAV signature in vibrational circular dichroism (VCD) spectra.

Spin-dependent charge transmission through chiral 2T3N self-assembled monolayer on Au.

A gold surface is functionalized by chemisorption of the enantiopure N,N'-bis-[2,2';5',2″]tert-thiophene-5-yl methylcyclohexane-1,2-diamine (2T3N), a chiral oligothiophene derivative, via overnight incubation in a 2T3N ethanol solution. The Au|2T3N interface is characterized by x-ray photoelectron circular dichroism and comparing x-ray photoemission spectroscopy and electro-desorption results. Charge transmission at the Au|2T3N| solution interface is characterized by recording the cyclic voltammetry of the Fe(III)/Fe(II) reversible redox couple, finding a charge transfer rate constant, k°, variation from 1 × 10-1 to 3.3 × 10-2 cm s-1, when comparing the bare Au and the Au|2T3N interfaces, respectively. The "anomalous" high value of k° found for the chiral Au|2T3N interface can be rationalized on the basis of the chiral-induced spin selectivity effect, as further proved by magnetic-conductive atomic force microscopy measurements at room temperature. A spin polarization of about 30% is found.

Ethanol electro-oxidation reaction on the Pd(111) surface in alkaline media: insights from quantum and molecular mechanics.

The ethanol electro-oxidation catalyzed by Pd in an alkaline environment involves several intermediate reaction steps promoted by the hydroxyl radical, OH. In this work, we report on the dynamical paths of the first step of this oxidation reaction, namely the hydrogen atom abstraction CH3CH2OH + OH → CH3CHOH + H2O, occurring at the Pd(111) surface and address the thermodynamic stability of the adsorbed reactants by means of quantum and molecular mechanics calculations, with special focus on the effect of the solvent. We have found that the impact of the solvent is significant for both ethanol and OH, contributing to a decrease in their adsorption free energies by a few dozen kcal mol-1 with respect to the adsorption energy under vacuum. Furthermore, we observe that hydrogen atom abstraction is enhanced for those simulation paths featuring large surface-reactant distances, namely, when the reactants weakly interact with the catalyst. The picture emerging from our study is therefore that of a catalyst whose coverage in an aqueous environment is largely dominated by OH with respect to ethanol. Nevertheless, only a small amount of them, specifically those weakly bound to the catalyst, is really active in the ethanol electro-oxidation reaction. These results open the idea of a rational design of co-catalysts based on the tuning of surface chemical properties to eventually enhance exchange current density.

On the Dynamics of the Carbon-Bromine Bond Dissociation in the 1-Bromo-2-Methylnaphthalene Radical Anion.

This paper studies the mechanism of electrochemically induced carbon-bromine dissociation in 1-Br-2-methylnaphalene in the reduction regime. In particular, the bond dissociation of the relevant radical anion is disassembled at a molecular level, exploiting quantum mechanical calculations including steady-state, equilibrium and dissociation dynamics via dynamic reaction coordinate (DRC) calculations. DRC is a molecular-dynamic-based calculation relying on an ab initio potential surface. This is to achieve a detailed picture of the dissociation process in an elementary molecular detail. From a thermodynamic point of view, all the reaction paths examined are energetically feasible. The obtained results suggest that the carbon halogen bond dissociates following the first electron uptake follow a stepwise mechanism. Indeed, the formation of the bromide anion and an organic radical occurs. The latter reacts to form a binaphthalene intrinsically chiral dimer. This paper is respectfully dedicated to Professors Anny Jutand and Christian Amatore for their outstanding contribution in the field of electrochemical catalysis and electrosynthesis.

Low-Cost Potentiometric Sensor for Chloride Measurement in Continuous Industrial Process Control.

Recently, the new updates in legislation about drinking water control and human health have increased the demand for novel electrochemical low-cost sensors, such as potentiometric ones. Nowadays, the determination of chloride ion in aqueous solutions has attracted great attention in several fields, from industrial processes to drinking water control. Indeed, chloride plays a crucial role in corrosion, also influencing the final taste of beverages, especially coffee. The main goal is to obtain devices suitable for continuous and real-time analysis. For these reasons, we investigated the possibility to develop an easy, low-cost potentiometric chloride sensor, able to perform analysis in aqueous mediums for long immersion time and reducing the need of periodic calibration. We realized a chloride ion selective electrode made of Ag/AgCl sintered pellet and we tested its response in model solutions compatible with drinking water. The sensor was able to produce a stable, reproducible, and accurate quantification of chloride in 900 s, without the need for a preliminary calibration test. This opens the route to potential applications of this sensor in continuous, in situ, and real time measurement of chloride ions in industrial processes, with a reduced need for periodic maintenance.

Electrodeposition of Molybdenum Disulfide (MoS2) Nanoparticles on Monocrystalline Silicon.

Molybdenum disulfide (MoS2) has attracted great attention for its unique chemical and physical properties. The applications of this transition metal dichalcogenide (TMDC) range from supercapacitors to dye-sensitized solar cells, Li-ion batteries and catalysis. This work opens new routes toward the use of electrodeposition as an easy, scalable and cost-effective technique to perform the coupling of Si with molybdenum disulfide. MoS2 deposits were obtained on n-Si (100) electrodes by electrochemical deposition protocols working at room temperature and pressure, as opposed to the traditional vacuum-based techniques. The samples were characterized by X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Rutherford Back Scattering (RBS).

Joint replacement for the management of haemophilic arthropathy in patients with inhibitors: A long-term experience at a single Haemophilia centre.

INTRODUCTION: The association between haemophilia and the so-called 'inhibitors', alloantibodies against the infused factor able to neutralize its clotting activity, is a very rare condition. Those sporadic patients suffer of an even more severe arthropathy and performing primary or revision arthroplasty become truly challenging. Literature about this topic is scarce, consisting in small case series, high rates of complications and mid-term follow-ups. AIM: The purpose of this study is the assessment of the long-term outcomes of primary and revision arthroplasty performed in a population of patients with inhibitors, the more consistent to date reported at a single haemophilia centre. METHODS: We reviewed the records of 18 patients with inhibitors (26 procedures) between 1999 and 2017, divided in two groups. Group A [primary total Knee-Hip arthroplasty (TKA-THA)]: 13 patients underwent 19TKA and 2THA; and B (revision): 5 subjects underwent 3rTKA and 2rTHA. All patients received the same haematological prophylaxis (rFVIIa). Haemophilic Joint Health score and VAS, and X-rays were recorded pre- and postoperatively. The survival rate of all primary implants was assessed. RESULTS: The median follow-up was 12.2 years (3-21) for group A, 8.6 years (4-12) for B. Few complications have been reported; the overall survival rate was 94.7% at 15 years. All patients reported satisfaction, pain reduction and improved functional ability. CONCLUSION: Primary and revision TKA/THA in haemophilic subjects and inhibitors may be nowadays considered safe and effective if performed in dedicated multidisciplinary centres. The use of continuous infusion of rFVIIa showed an adequate haemostatic effect and low rate of complications. As expected, revisions are more prone to complications compared to primary arthroplasty.

The Fundamental and Underrated Role of the Base Electrolyte in the Polymerization Mechanism. The Resorcinol Case Study.

The Kane-Maguire polymerization mechanism is disassembled at a molecular level by using DFT-based quantum mechanical calculations. Resorcinol electropolymerization is selected as a case study. Stationary points (transition states and intermediate species) leading to the formation of the dimer are found on the potential energy surface (PES), and elementary reactions involved in the dimer formation are characterized. The latter allow to further propagate the polymerization chain reaction, when applied recursively. In this paper, the fundamental role of the sulfate anion (a typical base electrolyte) is addressed. Investigation of the PES in terms of both stationary-state properties and of ab initio molecular dynamics results (dynamic reaction coordinate) allows the appreciation in detail of the critical role of the base electrolyte anion in making the proton dissociation from the initial radical ion, a feasible (downhill in energy) process.

Patients Following Revision Total Hip Arthroplasty With Modular Dual Mobility Components and Cobalt-Chromium Inner Metal Head are at Risk of Increased Serum Metal Ion Levels.

BACKGROUND: Modular dual-mobility (MDM) total hip arthroplasty (THA) is designed with a cobalt-chromium liner inserted into a titanium acetabular component. The purpose of this study is to investigate the potential risks for fretting corrosion at this junction, by measuring serum metal ions, after MDM acetabular revision. METHODS: Thirty-seven patients with well-functioning revision THAs participated in a cross-sectional study at mean 5.1 (2-10) years after surgery. All received a trabecular titanium MDM acetabular component. The serum levels of cobalt and chromium were measured using mass spectrometry. RESULTS: The mean values of chromium and cobalt were 2.08 µg/L (95% confidence interval 0.9-3.2, range 0.02-11.8) and 1.99 µg/L (95% confidence interval 0.81-3.17, range 0.07-16.05), respectively. Eleven patients (29, 7%) had ion levels above the normal range, with 6 (16.2%) above 5 µg/L and 5 (13.5%) between 1 and 5 µg/L. A significant correlation was found between an elevated serum metal ion level and University of California Los Angeles score (P = .016). CONCLUSION: We conclude that serum metal level elevation may occur secondary to metal debris resulting from corrosion of the index MDM THA. This potential risk should be included in the decision-making process when dealing with revision arthroplasty in young and active patients.

Influence of Chiral Compounds on the Oxygen Evolution Reaction (OER) in the Water Splitting Process.

Results are presented concerning the influence on the water splitting process of enantiopure tartaric acid present in bulk solution. Stainless steel and electrodeposited nickel are used as working electrode (WE) surface. The latter is obtained by electrodeposition on the two poles of a magnet. The influence and role played by the chiral compound in solution has been assessed by comparing the current values, in cyclic voltammetry (CV) experiments, recorded in the potential range at which oxygen evolution reaction (OER) occurs. In the case of tartaric acid and nickel WE a spin polarization of about 4% is found. The use of the chiral environment (bulk solution) and ferromagnetic chiral Ni electrode allows for observing the OER at a more favorable potential: About 50 mV (i.e., a cathodic, less positive, shift of the potential at which the oxygen evolution is observed).

[Results of a vertebral deformity screening in the students of the district of Florence (Tuscany Region, Central Italy)]. / Risultati di uno screening per le deformità vertebrali tra gli studenti delle scuole del comune di Firenze.

OBJECTIVES: to observe the prevalence of vertebral deformities in an adolescent population in the 178 schools of the District of Florence (Tuscany Region, Central Italy), correlating these results with clinical aspects as ligamentous laxity and verifying if these data are in agreement with what emerged in literature in studies of the same type. DESIGN: prevalence study. SETTING AND PARTICIPANTS: report of the results of a school screening for vertebral deformities in an adolescent population of 11,820 students of the Schools of District of Florence held between November 2010 and June 2013. MAIN OUTCOMES MEASURES: asymmetry of waist triangle; trunk imbalance using plumb-line from C7; leg length discrepancies; presence of gibbus and measurement of Angle of Trunk Rotation using Bunnell scoliometer; measure of thoracic kyphosis (a value of kyphosis> 50° was considered to be at high risk of hyperkyphosis making it necessary to request an X-ray); ligamuentuos laxity using Beighton Score. RESULTS: 11,820 students were screened; 85.95% of them had no significant spinal deformities; 14,05% of the students showed significant clinical signs of scoliosis; 28.46% of the students had a thoracic hyperkyphosis (>40°), 1.55% of those presented a non-reducible thoracic hyperkyphosis. Results show a statistically significant correlation between the severity of the deformities and the score of the Beighton Score. CONCLUSIONS: the results confirm the association between vertebral deformities and ligament laxity. The prevalence of vertebral deformities in the school age population of the Municipality of Florence is 14.05%, in accordance with what emerged in the literature from similar studies.

Partial rupture of anterior cruciate ligament: preliminary experience of selective reconstruction.

BACKGROUND: Partial lesions of the anterior cruciate ligament (ACL) are more common than is generally thought, accounting for about 10-12% of ACL injuries. Selective reconstruction may be considered as an option in isolated bundle rupture. The purpose of this study is to evaluate both subjective and objective clinical results, as well as functional recovery time, after selective arthroscopic single-bundle reconstruction in a consecutive series of patients affected by partial ACL rupture. MATERIALS AND METHODS: Thirty-six patients undergoing selective reconstruction of a single ACL bundle were retrospectively evaluated from a series of 354 ACL reconstructions performed over a 3-year period. Although the suspicion of partial lesions was present at clinical and magnetic resonance imaging (MRI) evaluation, final diagnosis was obtained during arthroscopy. All patients were operated using the same technique and type of fixation, and undergoing the same functional recovery protocol. RESULTS: Mean follow-up was 64 months (48-84 months). All patients but one achieved good functional recovery and returned to their sports within a mean period of 6.1 months. A single patient complained of postoperative instability 1 year after the index operation and needed further surgery. No complications were recorded. CONCLUSIONS: Selective reconstruction of partial ACL injury is a method to bear in mind because it offers quick functional recovery. Specific technical and diagnostic steps should be performed and discussed with patients preoperatively. LEVEL OF EVIDENCE: Level 4, retrospective study.

Total Knee Arthroplasty in Patients With Extra-Articular Deformity: Restoration of Mechanical Alignment Using Accelerometer-Based Navigation System.

BACKGROUND: Total knee arthroplasty (TKA) in patients with post-traumatic extra-articular deformity (EAD) is difficult to manage using conventional instrumentation techniques. In this study, we evaluate whether accelerometer navigation system can be a valuable option to make accurate bone resections and restore the neutral mechanical axis in complex TKA patients with EAD. METHODS: From May 2015 to June 2017, 18 consecutive TKA were performed in 18 patients with knee osteoarthritis with associated EAD. An accelerometer-based navigation system was used to guide tibial and femoral resection in the coronal and sagittal plane. Postoperative lower limb alignment in coronal plane and component position in coronal and sagittal plane was measured through full-leg weight-bearing X-ray. Clinical score were recorded using the Knee Society Score at the final follow-up. RESULTS: The mean hip-knee-ankle angle was 0.9° ± 1.4° varus alignment. The coronal alignment of the femoral component was 89.2° ± 1.9°, and the coronal alignment of the tibial component was 89.4° ± 2.1°. The sagittal alignment of the femoral component was 93.2°± 1.9°, and the sagittal alignment of the tibial component was 84.4° ± 3.1°. At the final follow-up, the Knee Society Score was 89 points (range, 82-100), and the functional score was 86.7 points (range, 60-100). No intraoperative and postoperative surgical complications were reported using this technology. CONCLUSION: Accelerometer-based navigation is accurate in achieving neutral mechanical alignment and optimal implant position after TKA in patients with EAD. This system should be considered a valuable option to the more complex technique of computer navigation or robotic surgery.

The anterior-based muscle-sparing approach to the hip: the "other" anterior approach to the hip.

PURPOSE: The purpose of this study was to evaluate safety, efficacy, and learning curves of anterior-based muscle-sparing total hip arthroplasty (ABMS-THA) in the supine position. Furthermore, early functional outcome was evaluated and compared to direct anterior approach (DAA) by measuring surface electromyography (sEMG). METHODS: We present a prospective cohort study of 343 hips. The safety and learning curve were assessed by recording operative time and peri-operative adverse events. For assessment of efficacy, functional and radiological outcomes were evaluated. A selected group of 32 patients have been studied by sEMG and compared to a matched group of 32 patients who received a THA using DAA approach. RESULTS: There was one dislocation (0.3%); two (0.6%) patients had an intra-operative fractures of the greater trochanter; two patients (0.6%) experienced a self-limited femoral nerve palsy. Physical therapy milestones for hospital discharge were reached on an average of 1.7 days. sEMG showed that ABMS and DAA have a similar muscle recruitment pattern and functional recovery after THA. One patient was revised for infection, 16 were lost, and 326 hips were available with a median follow-up of 42 months (range 24-60). The mean Harris Hip Score (HSS) increased from 44.3 to 91.9. Ninety-six percent of the hips had a leg length discrepancy (LLD) < 5 mm. There were no radiological signs of mechanical loosening or osteolysis. CONCLUSIONS: The ABMS approach in the supine position is clinically effective and safe; special advantages include a very low dislocation rate and a great control of LLD.

Functional outcomes and mortality in geriatric and fragility hip fractures-results of an integrated, multidisciplinary model experienced by the "Florence hip fracture unit".

PURPOSE: The aim of this study was to evaluate the outcomes of an integrated multidisciplinary hip fracture unit through the following parameters: time to surgery, mortality, return to activities of daily living, adherence to re-fractures prevention programs. METHODS: Six hundred seventy-seven consecutive patients with hip fracture were included in the study. We calculated the time to surgery as the time in hours from admission until surgery. The in-hospital mortality was calculated as the number of deaths that occurred before discharge. Each patient was then evaluated post-operatively at six weeks, three months, and one year. We studied basic activity of daily living (BADL) and the New Mobility Scale (NMS). Adherence to re-fractures prevention programs was also evaluated. RESULTS: 88.9% of patients underwent surgery within two calendar days from admission. In-hospital mortality was 2.4%, and the overall mortality at one year from the intervention was 18.7%. Full mobility status or a low impairment of the mobility status was reached in 32.1% of the patients at one year and a level ≥ 3 of autonomy in BADL was reached in 62.4% (338/542) of patients. Three hundred forty-two patients were prescribed a specific therapy for secondary prevention of re-fracture. CONCLUSIONS: An integrated, multidisciplinary model for the treatment of hip fragility fractures was effective in reducing time to surgery and mortality, increasing the level autonomy and mobility status and promoting adherence to re-fracture therapy.

MWCNTs-Supported Pd(II) Complexes with High Catalytic Efficiency in Oxygen Reduction Reaction in Alkaline Media.

We report here the remarkable catalytic efficiency observed for two Pd(II) azamacrocyclic complexes supported on multiwalled carbon nanotubes (MWCNTs) toward oxygen reduction reactions. Beyond a main (>90%) 4e- process and an onset potential close to or better than those of commercial Pt electrodes, the MWCNTs functionalization strategy, aimed at chemically defined Pd(II)-based catalytic centers, allowed the half-cell to exceed the proton-exchange-membrane fuel-cell reference/target mass activity efficiency set by the U.S. Department of Energy for 2020 (440 mA/mgPGM at 0.9 V vs reversible hydrogen electrode).

Post-operative 3D CT feedback improves accuracy and precision in the learning curve of anatomic ACL femoral tunnel placement.

PURPOSE: To evaluate the feedback from post-operative three-dimensional computed tomography (3D-CT) on femoral tunnel placement in the learning process, to obtain an anatomic anterior cruciate ligament (ACL) reconstruction. METHODS: A series of 60 consecutive patients undergoing primary ACL reconstruction using autologous hamstrings single-bundle outside-in technique were prospectively included in the study. ACL reconstructions were performed by the same trainee-surgeon during his learning phase of anatomic ACL femoral tunnel placement. A CT scan with dedicated tunnel study was performed in all patients within 48 h after surgery. The data obtained from the CT scan were processed into a three-dimensional surface model, and a true medial view of the lateral femoral condyle was used for the femoral tunnel placement analysis. Two independent examiners analysed the tunnel placements. The centre of femoral tunnel was measured using a quadrant method as described by Bernard and Hertel. The coordinates measured were compared with anatomic coordinates values described in the literature [deep-to-shallow distance (X-axis) 28.5%; high-to-low distance (Y-axis) 35.2%]. Tunnel placement was evaluated in terms of accuracy and precision. After each ACL reconstruction, results were shown to the surgeon to receive an instant feedback in order to achieve accurate correction and improve tunnel placement for the next surgery. Complications and arthroscopic time were also recorded. RESULTS: Results were divided into three consecutive series (1, 2, 3) of 20 patients each. A trend to placing femoral tunnel slightly shallow in deep-to-shallow distance and slightly high in high-to-low distance was observed in the first and the second series. A progressive improvement in tunnel position was recorded from the first to second series and from the second to the third series. Both accuracy (+52.4%) and precision (+55.7%) increased from the first to the third series (p < 0.001). Arthroscopic time decreased from a mean of 105 min in the first series to 57 min in the third series (p < 0.001). After 50 ACL reconstructions, a satisfactory anatomic femoral tunnel was reached. CONCLUSION: Feedback from post-operative 3D-CT is effective in the learning process to improve accuracy and precision of femoral tunnel placement in order to obtain anatomic ACL reconstruction and helps to reduce also arthroscopic time and learning curve. For clinical relevance, trainee-surgeons should use feedback from post-operative 3DCT to learn anatomic ACL femoral tunnel placement and apply it appropriately. LEVEL OF EVIDENCE: Consecutive case series, Level IV.

Effect of Electrode Shape and Flow Conditions on the Electrochemical Detection with Band Microelectrodes.

In this work, we report the analysis of the electrochemical detection of electroactive species with band microelectrodes that operate under controlled convection. The study focuses on the determination of the collection efficiency of the analyte as a function of inlet flow velocity and microband geometry (inlaid, bumped and recessed), also providing a straightforward method for the theoretical determination of the lower detection limit. The analysis has been carried out by simulating the dimensionless mass transport with the finite element method, delivering the stationary limiting current density. Simulations have been performed on systems consisting of single and double band electrodes to investigate the trail effect on the electrochemical detection. We show that the obtained dimensionless results can be easily turned into dimensional data, providing a tool for the design of devices. The proposed method is general and can easily be extended to systems with different geometry.

The kinetics of remodeling of a calcium sulfate/calcium phosphate bioceramic.

In the last years considerable research and development activity have been expended to find new ceramic bone substitutes for the treatment of bone defects. However in many cases the drawback of synthethic bone substitutes are the slow graft incorporation and remodelling into the host bone. The purpose of this study was to analyze the kinetics of resorption and new bone formation of new calcium sulfate (CaSO4)/calcium phosphate (CaPO4) bioceramic engineered to enhance its bone forming properties. We prospectively evaluated the results of a series of 15 hips with osteonecrosis of the femoral head (ONFH) treated at with core decompression and injection of the CaSO4/CaPO4 composite. In all hips, a quantitative computed tomography (QTC) scan was taken within one week after the surgery, at 12 months, 2 years and finally with a minimum of 4 years follow-up. The mean HU in the immediate post-operative period was 1445 (Range 1388-1602); At one year the mean HU strongly decrease at 556.6 HU (P < 0.01); The mean HU at 2 years follow-up further decreased to 475.1. The mean HU at 4 years was unchanged. The quantitative and qualitative CT scan data of this series indicates that the CaSO4-CaPO4 ceramic composite resorbs over a narrow timeframe and the gradual resorption of the graft within the defect provides an ideal environment for the direct new bone growth that propagates across the defect.