Continuous-Flow Synthesis of Arylthio-Cyclopropyl Carbonyl Compounds.

The straightforward, continuous-flow synthesis of cyclopropyl carbaldehydes and ketones has been developed starting from 2-hydroxycyclobutanones and aryl thiols. This acid-catalyzed mediated procedure allows access to the multigram and easily scalable synthesis of cyclopropyl adducts under mild conditions, using reusable Amberlyst-35 as a catalyst. The resins, suitably ground and used for filling steel columns, have been characterized via TGA, ATR, SEM and BET analyses to describe the physical-chemical properties of the packed bed and the continuous-flow system in detail. To highlight the synthetic versatility of the arylthiocyclopropyl carbonyl compounds, a series of selective oxidation reactions have been performed to access sulfoxide and sulfone carbaldehyde cyclopropanes, oxiranes and carboxylic acid derivatives.

Evolution of nanomechanical properties and crystallinity of individual titanium dioxide nanotube resonators.

Herein a complete characterization of single TiO2 nanotube resonator was reported for the first time. The modal vibration response analysis allows a non-invasive indirect evaluation of the mechanical properties of the TiO2 nanotube. The effect of post-grown thermal treatments on nanotube mechanical properties was investigated and carefully correlated to the chemico-physical parameters evolution. The Young's modulus of TiO2 nanotube rises linearly from 57 GPa up to 105 GPa for annealing at 600 °C depending on the compositional and crystallographic evolution of the nanostructure. Considering the growing interest in single nanostructure devices, the reported findings allow a deeper understanding of the properties of individual titanium dioxide nanotubes extrapolated from their standard arrayed architecture.

Graphene as Barrier to Prevent Volume Increment of Air Bubbles over Silicone Polymer in Aqueous Environment.

The interaction of air bubbles with surfaces immersed in water is of fundamental importance in many fields of application ranging from energy to biology. However, many aspects of this topic such as the stability of surfaces in contact with bubbles remain unexplored. For this reason, in this work, we investigate the interaction of air bubbles with different kinds of dispersive surfaces immersed in water. The surfaces studied were polydimethylsiloxane (PDMS), graphite, and single layer graphene/PDMS composite. X-ray photoelectron spectroscopy (XPS) analysis allows determining the elemental surface composition, while Raman spectroscopy was used to assess the effectiveness of graphene monolayer transfer on PDMS. Atomic force microscopy (AFM) was used to study the surface modification of samples immersed in water. The surface wettability has been investigated by contact angle measurements, and the stability of the gas bubbles was determined by captive contact angle (CCA) measurements. CCA measurements show that the air bubble on graphite surface exhibits a stable behavior while, surprisingly, the volume of the air bubble on PDMS increases as a function of immersion time (bubble dynamic evolution). Indeed, the air bubble volume on the PDMS rises by increasing immersion time in water. The experimental results indicate that the dynamic evolution of air bubble in contact with PDMS is related to the rearrangement of surface polymer chains via the migration of the polar groups. On the contrary, when a graphene monolayer is present on PDMS, it acts as an absolute barrier suppressing the dynamic evolution of the bubble and preserving the optical transparency of PDMS.

New insights on laser-induced graphene electrodes for flexible supercapacitors: tunable morphology and physical properties.

In certain polymers the graphenization of carbon atoms can be obtained by laser writing owing to the easy absorption of long-wavelength radiation, which generates photo-thermal effects. On a polyimide surface this process allows the formation of a nanostructured and porous carbon network known as laser-induced graphene (LIG). Herein we report on the effect of the process parameters on the morphology and physical properties of LIG nanostructures. We show that the scan speed and the frequency of the incident radiation affect the gas evolution, inducing different structure rearrangements, an interesting nitrogen self-doping phenomenon and consequently different conduction properties. The materials were characterized by infrared and Raman spectroscopy, XPS elemental analysis, electron microscopy and electrical/electrochemical measurements. In particular the samples were tested as interdigitated electrodes into electrochemical supercapacitors and the optimized LIG arrangement was tested in parallel and series supercapacitor configurations to allow power exploitation.

Electrodes/electrolyte interfaces in the presence of a surface-modified photopolymer electrolyte: application in dye-sensitized solar cells.

Since hundreds of studies on photoanodes and cathodes show that the electrode/electrolyte interfaces represent a key aspect at the base of dye-sensitized solar cell (DSSC) performances, it is reported here that these interfaces can be managed by a smart design of the spatial composition of quasi-solid electrolytes. By means of a cheap, rapid, and green process of photoinduced polymerization, composition-tailored polymer electrolyte membranes (PEMs) with siloxane-enriched surfaces are prepared, and their properties are thoroughly described. When assembled in DSSCs, the interfacial action promoted by the composition-tailored PEMs enhances the photocurrent and fill factor values, thus increasing the global photovoltaic conversion efficiency with respect to the non-modified PEMs. Moreover, the presence of the siloxane-chain-enriched surface increases the hydrophobicity and reduces the water vapor permeation into the device, thus enhancing the cell's durability.

A UV-crosslinked polymer electrolyte membrane for quasi-solid dye-sensitized solar cells with excellent efficiency and durability.

Here we report on a novel polymer electrolyte membrane for quasi-solid dye-sensitized solar cells (DSSCs) with excellent efficiency and extended durability. The electrolyte is prepared by an elegant, rapid and cheap UV-induced polymerization method and the chemometric approach is used for the first time, to the best of our knowledge, for the optimization and the fine tuning of the experimental conditions.

Charge transport improvement employing TiO2 nanotube arrays as front-side illuminated dye-sensitized solar cell photoanodes.

TiO(2) nanotube (NT) arrays with different lengths were fabricated by anodic oxidation of Ti foil and free-standing NT membranes were detached by the metal substrate and bonded on the fluorine-doped tin oxide surface implementing an easy procedure. Morphology of the as-grown material and of the prepared photoanode was investigated by means of electron microscopy, deepening the investigation on the thermal treatment effect. Crystalline orientation and exposed surface area were studied by X-ray diffraction and Brunauer-Emmett-Teller measurements, showing suitable characteristics for the application in dye-sensitized solar cells (DSCs). DSCs were assembled employing a microfluidic housing system. The cell performances and the electron transport properties as a function of the tube length, before and after a TiCl(4) treatment, were characterized by I-V electrical measurements, incident photon-to-electron conversion efficiency, electrochemical impedance spectroscopy and open circuit voltage decay. Fitting the impedance spectra with an equivalent circuit, it was possible to obtain information on the electron diffusion properties into the TiO(2) nanotubes. A comparison with the charge transport properties evaluated in nanoparticle-based photoanodes witnesses a noteworthy increase of electron lifetime and diffusion length, yielding an overall power conversion efficiency up to 7.56%.

Combined experimental and theoretical investigation of the hemi-squaraine/TiO2 interface for dye sensitized solar cells.

A simple hemi-squaraine dye (CT1) has been studied as a TiO2 sensitizer for application in dye sensitized solar cells (DSCs) by means of a combined experimental and theoretical investigation. This molecule is a prototype dye presenting an innovative anchoring group: the squaric acid moiety. Ab initio calculations based on Density Functional Theory (DFT) predict that this acid spontaneously deprotonates at the anatase (101) surface forming chemical bonds that are stronger than the ones formed by other linkers (e.g. cathecol and isonicotinic acid). Moreover an analysis of the electronic structure of the hybrid interface reveals the formation of a type II heterostructure ensuring adiabatic electron transfer from the molecule to the oxide. DSCs containing hemi-squaraine dyes were assembled, characterized and their performances compared to state of the art cells. Experimental results (large incident photon-to-electron conversion efficiency and an efficiency of 3.54%) confirmed the theoretical prediction that even a simple hemi-squaraine is an effective sensitizer for TiO2. Our study paves the way to the design of more efficient sensitizers based on a squaric acid linker and specifically engineered to absorb light in a larger part of the visible range.

Ultrasonic Spray Coating to Optimize Performance of Bio-Electrochemical Systems.

This work investigates the optimization of carbon-based electrodes employed in bio-electrochemical systems (BES) through the deposition of nanostructured layers of poly(3,4-ethylene-dioxy-thiophene) poly(styrene-sulfonate) (PEDOT:PSS) on commercial carbon paper electrodes via ultrasonic spray coating (USC). This innovative application of USC demonstrated that uniform and controlled depositions of PEDOT:PSS can be successfully performed on carbon-based electrodes. To this end, the morphology and spatial uniformity of depositions were verified via scanning electron microscopy and Raman spectroscopy. Electrochemical characterizations of fabricated electrodes demonstrated a more than two-fold increase in the electrochemical active surface area with respect to bare carbon paper. A lab-scale experiment on BES was performed, selecting microbial fuel cells (MFCs) as the reference devices. Devices featuring USC-deposited PEDOT:PSS electrodes showed a three-fold-higher energy recovery with respect to control cells, reaching a maximum value of (13 ± 2) J·m-3. Furthermore, the amount of PEDOT:PSS required to optimize MFCs' performance is in line with values reported in the literature for other deposition methods. In conclusion, this work demonstrates that USC is a promising technique for application in BES.

High efficiency dye-sensitized solar cells exploiting sponge-like ZnO nanostructures.

Sponge-like nanostructured ZnO layers were successfully employed as photoanodes for the fabrication of highly efficient dye-sensitized solar cells. The sponge-like ZnO layers were obtained by room temperature radio-frequency magnetron sputtering deposition of metallic zinc, followed by thermal oxidation treatment in an ambient atmosphere. The porous films show a 3D branched nanomorphology, with a feature similar to natural coral. The morphological and optical properties of these layers were studied through field emission scanning electron microscopy, specific surface area measurements, ultraviolet-visible transmittance and absorption spectroscopy. The sponge-like ZnO film presents a high density of branches, with a relatively high specific surface area value, and fine optical transmittance. The morphology of the porous structure provides a high number of adsorption sites for the anchoring of sensitizer molecules, making it suitable for the fabrication of ZnO-based photoanodes for dye-sensitized solar cells. The light harvesting performance of the sensitized semiconductor was evaluated by current density vs. voltage measurements, incident photon-to-electron conversion efficiency, open circuit voltage decay and impedance spectroscopy. The modelling of the electrical characteristics evidences a higher electron lifetime and a longer charge diffusion length, if compared to standard TiO(2) nanoparticle based photoanodes. For ZnO films with a thickness up to 18 µm, a photoconversion efficiency as high as 6.67% and a maximum value of the incident photon-to-electron collection efficiency equal to 87% at 530 nm were demonstrated.

Modification of the solid-state nature of sulfathiazole and sulfathiazole sodium by spray drying.

Solid-state characterisation of a drug following pharmaceutical processing and upon storage is fundamental to successful dosage form development. The aim of the study was to investigate the effects of using different solvents, feed concentrations and spray drier configuration on the solid-state nature of the highly polymorphic model drug, sulfathiazole (ST) and its sodium salt (STNa). The drugs were spray-dried from ethanol, acetone and mixtures of these organic solvents with water. Additionally, STNa was spray-dried from pure water. The physicochemical properties including the physical stability of the spray-dried powders were compared to the unprocessed materials. Spray drying of ST from either acetonic or ethanolic solutions with the spray drier operating in a closed cycle mode yielded crystalline powders. In contrast, the powders obtained from ethanolic solutions with the spray drier operating in an open cycle mode were amorphous. Amorphous ST crystallised to pure form I at ≤35 % relative humidity (RH) or to polymorphic mixtures at higher RH values. The usual crystal habit of form I is needle-like, but spherical particles of this polymorph were generated by spray drying. STNa solutions resulted in an amorphous material upon processing, regardless of the solvent and the spray drier configuration employed. Moisture induced crystallisation of amorphous STNa to a sesquihydrate, whilst crystallisation upon heating gave rise to a new anhydrous polymorph. This study indicated that control of processing and storage parameters can be exploited to produce drugs with a specific/desired solid-state nature.

Crown-Ether Functionalized Graphene Oxide Membrane for Lithium Recovery from Water.

The massive worldwide transition of the transport sector to electric vehicles has dramatically increased the demand for lithium. Lithium recovery by means of ion sieves or supramolecular chemistry has been extensively studied in recent years as a viable alternative approach to the most common extraction processes. Graphene oxide (GO) has also already been proven to be an excellent candidate for water treatment and other membrane related applications. Herein, a nanocomposite 12-crown-4-ether functionalized GO membrane for lithium recovery by means of pressure filtration is proposed. GO flakes were via carbodiimide esterification, then a polymeric binder was added to improve the mechanical properties. The membrane was then obtained and tested on a polymeric support in a dead-end pressure setup under nitrogen gas to speed up the lithium recovery. Morphological and physico-chemical characterizations were carried out using pristine GO and functionalized GO membranes for comparison with the nanocomposite. The lithium selectivity was proven by both the conductance and ICP mass measurements on different sets of feed and stripping solutions filtrated (LiCl/HCl and other chloride salts/HCl). The membrane proposed showed promising properties in low concentrated solutions (7 mgLi/L) with an average lithium uptake of 5 mgLi/g in under half an hour of filtration time.

A 3-gene biomarker signature to predict response to taxane-based neoadjuvant chemotherapy in breast cancer.

Breast cancer is the most common cancer in women worldwide, affecting one in eight women in their lifetime. Taxane-based chemotherapy is routinely used in the treatment of breast cancer. The purpose of this study was to develop and validate a predictive biomarker to improve the benefit/risk ratio for that cytotoxic chemotherapy. We explicitly strived for a biomarker that enables secure translation into clinical practice. We used genome-wide gene expression data of the Hatzis et al. discovery cohort of 310 patients for biomarker development and three independent cohorts with a total of 567 breast cancer patients for validation. We were able to develop a biomarker signature that consists of just the three gene products ELF5, SCUBE2 and NFIB, measured on RNA level. Compared to Hatzis et al., we achieved a significant improvement in predicting responders and non-responders in the Hatzis et al. validation cohort with an area under the receiver operating characteristics curve of 0.73 [95% CI, 69%-77%]. Moreover, we could confirm the performance of our biomarker on two further independent validation cohorts. The overall performance on all three validation cohorts expressed as area under the receiver operating characteristics curve was 0.75 [95% CI, 70%-80%]. At the clinically relevant classifier's operation point to optimize the exclusion of non-responders, the biomarker correctly predicts three out of four patients not responding to neoadjuvant taxane-based chemotherapy, independent of the breast cancer subtype. At the same time, the response rate in the group of predicted responders increased to 42% compared to 23% response rate in all patients of the validation cohorts.

Binder Free and Flexible Asymmetric Supercapacitor Exploiting Mn3O4 and MoS2 Nanoflakes on Carbon Fibers.

Emerging technologies, such as portable electronics, have had a huge impact on societal norms, such as access to real time information. To perform these tasks, portable electronic devices need more and more accessories for the processing and dispensation of the data, resulting in higher demand for energy and power. To overcome this problem, a low cost high-performing flexible fiber shaped asymmetric supercapacitor was fabricated, exploiting 3D-spinel manganese oxide Mn3O4 as cathode and 2D molybdenum disulfide MoS2 as anode. These asymmetric supercapacitors with stretched operating voltage window of 1.8 V exhibit high specific capacitance and energy density, good rate capability and cyclic stability after 3000 cycles, with a capacitance retention of more than 80%. This device has also shown an excellent bending stability at different bending conditions.

Graphene Oxide Membranes for Trace Hydrocarbon Contaminant Removal from Aqueous Solution.

The aim of this paper is to shed light on the application of graphene oxide (GO) membranes for the selective removal of benzene, toluene, and xylene (BTX) from wastewater. These molecules are present in traces in the water produced from oil and gas plants and are treated now with complex filtration systems. GO membranes are obtained by a simple, fast, and scalable method. The focus of this work is to prove the possibility of employing GO membranes for the filtration of organic contaminants present in traces in oil and gas wastewater, which has never been reported. The stability of GO membranes is analyzed in water solutions with different pH and salinity. Details of the membrane preparation are provided, resulting in a crucial step to achieve a good filtration performance. Material characterization techniques such as electron microscopy, x-ray diffraction, and infrared spectroscopy are employed to study the physical and chemical structure of GO membranes, while gas chromatography, UV-visible spectroscopy, and gravimetric techniques allow the quantification of their filtration performance. An impressive rejection of about 90% was achieved for 1 ppm of toluene and other pollutants in water, demonstrating the excellent performance of GO membranes in the oil and gas field.

High-temperature annealing effects on multiwalled carbon nanotubes: electronic structure, field emission and magnetic behaviors.

This work elucidates the effects of high-temperature annealing on the microscopic and electronic structure of multiwalled carbon nanotubes (MWCNTs) using high-resolution transmission electron microscopy, micro-Raman spectroscopy, X-ray diffraction, X-ray absorption near-edge structure (XANES) and valence-band photoemission spectroscopy (VBPES), respectively. The field emission and magnetization behaviors are also presented. The results of annealing are as follows: (1) MWCNTs tend to align in the form of small fringes along their length, promote graphitization and be stable in air, (2) XANES indicates an enhancement in oxygen content on the sample, implying that it can be adopted for sensing and storing oxygen gas, (3) the electron field emission current density (J) is enhanced and the turn-on electric field (E(TOE)) reduced, suggesting potential use in field emission displays and as electron sources in microwave tube amplifiers and (4) as-grown MWCNTs with embedded iron nanoparticles exhibits significantly higher coercivity approximately 750 Oe than its bulk counterpart (Fe(bulk) approximately 0.9 Oe), suggesting its potential use as low-dimensional high-density magnetic recording media.

Tarsometatarsal joint complex injuries: A study of injury pattern in complete homolateral lesions.

INTRODUCTION: Tarsometatarsal joint complex (TMC) is the anatomical structure of midfoot composed by metatarsals, tarsometatarsal (TMT) joints, cuneiforms, cuboid and navicular. TMC lesion are rare but critical since they cause severe disability if misdiagnosed. The knowledge of anatomic pattern of the lesion and biomechanics of the midfoot is the key for a successful diagnosis and treatment. The aim of this study was to review a consecutive series of TMC injuries analyzing preoperative radiograph and CT scan to accurately define the pattern of ligament and bone injuries. MATERIAL AND METHODS: We reviewed a series of 24 complete TMC injuries with homolateral dorsolateral dislocation. The total TMT joints involved were 120. We observed if the lesions were pure ligamentous or fracture-dislocation detecting the extent and the location of fractures. Twenty-nine lesions (24%) were pure dislocations and they were mainly localized in the first and fifth ray. The fracture-dislocations were 91 (76%) and 25 were fractures of the proximal row (cuneiforms and cuboid), 39 of the distal row (metatarsals), 27 of both the distal and proximal row. RESULTS: Proximal fracture had a homogeneous distribution and they were more frequently simple than comminuted. Comminuted fractures were more frequent in the cuboid. In the proximal row, majority of partial articular fractures were localized in the dorsal side. Fracture-dislocations of the distal row were more frequent in the second metatarsal base (100%) and the partial articular fractures were always placed in the plantar side. In TMC injuries fracture-dislocations are more frequent than pure dislocations. Pure dislocations occur more often in the marginal rays that are characterized by weaker ligaments and larger mobility. The second ray, where there is the more stable joint of TMC, was never dislocated with a pure ligamentous lesion. CONCLUSIONS: We suppose that plantar avulsion from the distal row and dorsal compression fracture of the proximal row is consistent with a direct force applied to the forefoot and direct dorsolaterally. The direction of the forces may explain why some fractures occur in the distal row, some in the proximal and some in both rows. The thickness of plantar ligaments may explain the frequency of plantar bone fragment avulsion.

Displaced intra-articular fractures of the calcaneus: ORIF through an extended lateral approach.

INTRODUCTION: Displaced intra-articular calcaneal fractures (DIACF) represent a challenging and controversial issue in traumatology. Conservative treatment has been recommended to avoid surgical problems and complications. The final result, however, is often a painful malunioun of the calcaneus with peroneal impingement. Surgical treatment is gaining acceptance since it offers a chance to restore bone anatomy improving function as long as complications are avoided. MATERIAL AND METHOD: We reviewed a series of 59 DIACF treated by a single surgeon during a 9 years period. A clinical and radiological follow-up was obtained in 44 cases (74,6%) (average of 5,5 years; range 2-9). There were 29 males and 15 females with an average age of 54 years (range 25-74). Patients were operated through an extended l-shaped lateral approach and fixation was achieved with lag screws and plate. Outcome measures method included the AOFAS score, the Maryland Foot Score, the Foot Function Index and the SF-36. RESULTS: The average AOFAS score was 80,5 points. The result was excellent in 18 cases (40,9%), good in 14 cases (31,8%), fair in 10 cases (22,7%) and poor in 2 (4,6%). The mean score for pain was 33,5/40 points, for function 40/50 and for alignment 7/10. Pain was absent in 17 cases (38%), 19 patients (43%) had no functional limitations and 11 (25%) could walk on uneven ground without difficulties. The average FFI score was 25/100 points. The average MFS score was 89/100 points. Subtalar motion was reduced. Reconstruction of the calcaneus was anatomic in 20 cases (45,5%) with an improved clinical outcome. Eight patients (17%) had minor wound healing complications. Three patients (6,8%) required a subtalar arthrodesis after the procedure. CONCLUSIONS: Ostheosytesis through an extended lateral approach restored bone morphology with a reasonable complications rate. The clinical results were good but a normal function and complete subtalar motion were rarely achieved.

PDMS/Polyimide Composite as an Elastomeric Substrate for Multifunctional Laser-Induced Graphene Electrodes.

Laser-induced graphene (LIG) emerged as one of the most promising materials for flexible functional devices. However, the attempts to obtain LIG onto elastomeric substrates never succeed, hindering its full exploitation for stretchable electronics. Herein, a novel polymeric composite is reported as a starting material for the fabrication of graphene-based electrodes by direct laser writing. A polyimide (PI) powder is dispersed into the poly(dimethylsiloxane) (PDMS) matrix to achieve an easily processable and functional elastomeric substrate, allowing the conversion of the polymeric surface into laser-induced graphene (LIG). The mechanical and electrical properties of the proposed material can be easily tuned by acting on the polyimide powder concentration. The reported procedure takes advantage from the simple casting process, typical of silicone elastomer, allowing to produce electrodes conformable to any kind of shape and surface as well as complex three-dimensional structures. Electrochemical capacitors and strain gauges are selected as flexible prototypes to demonstrate the multifunctional properties of the obtained LIG on the PDMS/PI composite substrate.

Subtrochanteric fractures: two case reports of non-union treatment.

Proximal femoral fractures are a very common disease which affect elderly patients after low energy trauma, but can also affect the young population as a consequence of high energy trauma. Classification of sub trochanteric fractures has not yet been clearly defined representing a major issue in comparing different treatment techniques among the scientific literature.These fractures are well known by orthopaedic surgeons for intraoperative difficulties in reduction and post-operative high rate of non-unions and malunions.We present two clinical cases, one treated with an intramedullary device and one with an extramedullary device, both failed and revised with open surgery using a condylar angled bladeplate, following AO principles of anatomical reduction and stable fixation.