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BACKGROUND: Standardized treatment of split-thickness skin graft (STSG) donor sites is not established. Bleeding can necessitate premature dressing changes, interrupting the healing process and increasing pain. PURPOSE: A collagen/oxidized regenerated cellulose (C/ORC) dressing was used on the donor site. The authors hypothesized that the collagen matrix could decrease bleeding-related complications, reduce pain, and foster epithelialization. METHODS: The C/ORC matrix was applied to the donor site after hemostasis was achieved. Dressings were removed between postoperative days 4 and 7, and the patients’ pain levels, bleeding complications, and percentage healed were recorded. RESULTS: Thirty-nine patients were treated with the C/ORC donor site dressing. Of these, 35 patients (89.7%) were receiving at least prophylactic anticoagulation, and no bleeding complications were recorded. The average area of donor sites was 123.8 cm2 (range, 20-528 cm2). Utilizing the Numerical Rating Scale, 25 patients (64.1%) reported no pain with dressing removal while 5 (12.8%) reported a decrease in pain. The percentage of epithelialization as assessed by treating clinician was at least equivalent to other modalities. CONCLUSIONS: The application of a C/ORC matrix to STSG donor wound sites resulted in no bleeding complications and excellent pain control while promoting epithelialization in the patients studied. Following this study, the C/ORC dressing has been incorporated into the authors’ standard protocol.

BACKGROUND: Necrotizing soft tissue infection (NSTI) is rare and characterized by rapid onset and spread of inflammation and necrosis. The infection starts within the fascia but can rapidly progress to include musculature, subcutaneous fat, and overlying skin. Its presentation is considered a surgical emergency. Persons who use intravenous or subcutaneous opioids are at higher risk of NSTIs. PURPOSE: The purpose of this case report is to describe the positive clinical outcome after consulting with wound specialists and using a dressing regimen to expedite more rapid wound healing, shortened time to skin graft, and improved pain tolerance in a patient with a history of intravenous and subcutaneous heroin use. CASE REPORT: The patient presented with an NSTI that required extensive debridement of the bilateral upper extremities. The acute surgical wound service was consulted. A dressing regimen consisting of hypochlorous acid–preserved wound cleansing, followed by carboxymethylcellulose fiber with 1.2% ionic silver covered by hydrocellular foam to promote a moist healing environment, was used to facilitate granulation. RESULTS: Healthy granulation tissue was noted 6 days after debridement. The improved rate of granulation and the patient’s tolerance to dressing changes secondary to decreased pain from these dressings significantly expedited the time to graft and wound healing. The patient underwent split-thickness skin grafting 10 days after debridement. There was 100% uptake of the grafts on postgraft day 8. CONCLUSION: The favorable clinical outcome suggests that early consultation with wound specialists and implementation of the dressing regimen were effective in this patient regarding improved pain control and healing. However, because the patient left against medical advice on hospital day 20, the clinical course could not be followed beyond the first few postoperative weeks.

A novel and controlled methodology combining UPS/XPS spectroscopies intended to determine the electronic state at the surface of ceria nanopowders.

Standardized treatment of split-thickness skin graft (STSG) donor sites is not established. Bleeding can necessitate premature dressing changes, interrupting the healing process and increasing pain.A collagen/oxidized regenerated cellulose (C/ORC) dressing was used on the donor site. The authors hypothesized that the collagen matrix could decrease bleeding-related complications, reduce pain, and foster epithelialization.The C/ORC matrix was applied to the donor site after hemostasis was achieved. Dressings were removed between postoperative days 4 and 7, and the patients' pain levels, bleeding complications, and percentage healed were recorded.Thirty-nine patients were treated with the C/ORC donor site dressing. Of these, 35 patients (89.7%) were receiving at least prophylactic anticoagulation, and no bleeding complications were recorded. The average area of donor sites was 123.8 cm2 (range, 20-528 cm2). Utilizing the Numerical Rating Scale, 25 patients (64.1%) reported no pain with dressing removal while 5 (12.8%) reported a decrease in pain. The percentage of epithelialization as assessed by treating clinician was at least equivalent to other modalities.The application of a C/ORC matrix to STSG donor wound sites resulted in no bleeding complications and excellent pain control while promoting epithelialization in the patients studied. Following this study, the C/ORC dressing has been incorporated into the authors' standard protocol.

Background Respiratory virus infections (RVI) are an important cause of pneumonia with increased risk of morbidity and mortality in patients with hematologic malignancies (HM) especially after stem cell transplantation. However, data on RVI in this population without stem cell transplant is still lacking. Here we aim to look at trends of RVI in HM population. Methods We conducted a retrospective cohort study of adult patients with HM diagnosed with RVI at our institution. We analyzed data from multiplex qualitative PCR-based respiratory viral panel (RVP) samples taken from January 2016 to June 2020. Lower respiratory tract infection (LRTI) was defined as abnormal chest radiography with positive RVP. Results Fifty-seven unique episodes were analyzed out of 54 patients. Thirty (52.6%) were females and the most common underlying malignancy was Non-Hodgkin’s Lymphoma (21, 36.8%). Median age was 61 (range 23-92) years old and 44/57 (77.1%) patients received chemotherapy within 30 days prior to RVI. Patient characteristics are summarized in Table 1. Most common viruses included Rhinovirus/Enterovirus (25, 43.8%), Influenza A/B (14, 24.5%) and RSV A/B (7,12.2%), respectively. Out of 39 patients who underwent chest imaging, 13/39 (33.3%) had evidence of LRTI. Out of 45 cases diagnosed as outpatients, 11/45 (24.4%) required hospital admission. ICU admission and mechanical ventilation were required in 5/57 (8.7%) and 2/57 (3.5%), respectively. Bacterial and fungal co-infection were seen in 1 (Pseudomonas spp) and 3 (Aspergillus spp.), respectively. Of note, only 1/57(1.8%) died at 30 days after RVI diagnosis. Conclusion Only one third developed LRTI after RVI in HM patients with very low 30-day mortality. However, we still found several bacterial and fungal co-infections. Thus, adequate diagnosis for RVI and co-infections with proper treatment should be required. Further studies with larger sample size are still needed. Disclosures All Authors: No reported disclosures.

Acute Myeloid Leukemia (AML) is an aggressive blood cancer in adults. Intensive induction therapy successfully induces a complete response in up to 80% of the adult patients but a fraction of them is refractory or relapses. The fraction of non-responsive or relapsing patients is especially high amongst medically unfit and older patients, who cannot undergo aggressive chemotherapy treatment. Therefore, offering patients failing on first line intensive chemotherapy and medically unfit and older patients an effective treatment option for long-term control or even cure of disease represents a significant yet unmet clinical need.As a component of the innate immunity, NK cells have recently shown great promise for the treatment of patients with different malignancies. Here, we show that injection of human interleukin-2 (IL-2) complexes (IL-2cx) induce the de novo generation and massive expansion of NK cell precursorsin vivo. Furthermore, IL-2cx-expanded NK cells exert effector functions with the capacity to control the growth of non-self MHC class I-deficient RMA-S lymphoma cellsin vivo, while remaining tolerant towards MHC class-expressing self RMA cells.In an experimental setup mimicking the clinical case of refractory patients after intensive AML induction therapy, IL-2cx treatment mediated strong anti-AML responses following haploidentical bone marrow transplantation without the need for adoptive transfer of donor-derived orin vitroautologous expanded NK cells. Thus, this study demonstrates that IL-2cx immunotherapy allows thein vivogeneration and expansion of functionally mature NK cells to achieve long-term response in AML paving the way to an effective treatment option.

A sequential analysis using Ultra-violet Photoelectron Spectroscopy (UPS) and X-ray Photoelectron Spectroscopy (XPS) on ceria nanopowders has been implemented to identify the influence of the X-ray beam on the surface of this oxide. For the first time, UPS analysis evidenced the photoreductive effect of XPS analysis on ceria after an oxidative

Tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC) are airway abnormalities that share a common feature of expiratory narrowing but are distinct pathophysiologic entities. Both entities are collectively referred to as expiratory central airway collapse (ECAC). The

Acute respiratory distress syndrome is treated by utilizing a lung protective ventilation strategy. Obesity presents with additional physiologic considerations, and optimizing ventilator settings may be limited with traditional means. Transpulmonary pressure (PRetrospective cohort study of obese (body mass index [BMI] ≥ 35 kg/mIntensive care unit in a community based hospital system in Newark, Delaware.Twenty-nine mechanically ventilated adult patients with a median BMI of 45.8 kg/mIndividualized titration of PEEP via esophageal catheter obtained transpulmonary pressures.Outcomes measured include PEEP, oxygenation, and driving pressure (DP) before and after esophageal manometry at 4 and 24 hr. Clinical outcomes including adverse events (pneumothorax and pneumomediastinum), increased vasopressor use, rescue therapies (inhaled pulmonary vasodilators, extracorporeal membrane oxygenation, and new prone position), continuous renal replacement therapy, and tracheostomy were also analyzed. Four hours after PEEP titration, median PEEP increased from 12 to 20 cm HP

Introduction Negative-pressure wound therapy (NPWT) with instillation and dwell time is an accepted adjunct therapy for infected wounds. A study was conducted to assess whether the use of hypochlorous acid preserved wound cleanser (HAPWOC) (Vashe, Urgo Medical North America, Fort Worth, TX, USA) as the irrigant would reduce the cost of care in comparison to 0.9% saline (NaCl). Method A comparative, observational, retrospective analysis assessed 27 serious and infected wounds in 24 patients. The lesions were of different and complex etiologies, including necrotizing fasciitis and stage IV diabetic foot ulcers. NPWT was used as part of the overall multimodal treatment regimen. The only variance in the treatment protocol was the use of saline (N=8) or HAPWOC (N=19) as the irrigant. Results When compared to NaCl, wounds treated with HAPWOC trended toward fewer operating room (OR) visits versus NaCl (3.3 versus 4.1) and a shorter length of hospital stay (LOS) (24.3 days versus 37.9 days). The Orlando Health Transparency guide shows the cost of OR debridement as $2,525. Thus, debridement for HAPWOC-treated wounds ($8,332) costs $2,020 (24%) less than for NaCl-treated wounds ($10,352). Using the 2016 Kaiser Health data (average daily hospital cost, excludingall interventions: $2,052), the cost of HAPWOC and NaCl instill translates to $49,864 and $77,771, respectively, a difference of $27,906 (56%) more for NaCl treatment. The Agency for Healthcare Research and Quality (AHRQ) 2012 data indicate an average daily cost of hospital stay, including all interventions, of $10,400. Thus, HAPWOC treatment cost translates to $252,720 versus NaCl-related costs of $394,160; in these calculations, using NaCl costs $141.440 (+56%) more per patient than HAPWOC. Conclusion The use of NPWT with HAPWOC versus NaCl as instillation in NPWT reduces the number of visits to the operating room and LOS. This has a significant impact on lowering the cost of care when HAPWOC is used.

Necrotizing soft tissue infection (NSTI) is rare and characterized by rapid onset and spread of inflammation and necrosis. The infection starts within the fascia but can rapidly progress to include musculature, subcutaneous fat, and overlying skin. Its presentation is considered a surgical emergency. Persons who use intravenous or subcutaneous opioids are at higher risk of NSTIs.The purpose of this case report is to describe the positive clinical outcome after consulting with wound specialists and using a dressing regimen to expedite more rapid wound healing, shortened time to skin graft, and improved pain tolerance in a patient with a history of intravenous and subcutaneous heroin use.The patient presented with an NSTI that required extensive debridement of the bilateral upper extremities. The acute surgical wound service was consulted. A dressing regimen consisting of hypochlorous acid-preserved wound cleansing, followed by carboxymethylcellulose fiber with 1.2% ionic silver covered by hydrocellular foam to promote a moist healing environment, was used to facilitate granulation.Healthy granulation tissue was noted 6 days after debridement. The improved rate of granulation and the patient's tolerance to dressing changes secondary to decreased pain from these dressings significantly expedited the time to graft and wound healing. The patient underwent split-thickness skin grafting 10 days after debridement. There was 100% uptake of the grafts on postgraft day 8.The favorable clinical outcome suggests that early consultation with wound specialists and implementation of the dressing regimen were effective in this patient regarding improved pain control and healing. However, because the patient left against medical advice on hospital day 20, the clinical course could not be followed beyond the first few postoperative weeks.

Rational design and precise engineering are needed to optimize the structural and chemical parameters of functional materials. In this work, we demonstrate how pre-formed binary metal selenides can be an excellent synthetic choice for the synthesis of ternary coinage metal selenide nanoparticles (NPs) with controlled composition. The mild conditions required to obtain these ternary coinage metal selenide NPs offered an easy synthesis of n% CuAgSe–TiO2 (n = 0.01, 0.1, 0.3 and 1.0 mol%) nanocomposites for photocatalytic applications without compromising the structural and morphological characteristics of TiO2 and without having any organic ligands around the NPs. The use of ternary metal selenide nanocomposites CuAgSe–TiO2 results in a clear improvement in their photocatalytic activity for the photodegradation of formic acid as compared to the well-known benchmark for photocatalysis, TiO2 (P25), and its binary metal selenide nanocomposites Cu2−xSe–TiO2. DFT calculations establish semi-metallic behavior of CuAgSe NPs and show that CuAgSe–TiO2 forms a semimetallic-semiconductor heterojunction allowing a better charge separation to enhance its photocatalytic activity.

An accurate experimental determination of electronic structures in semi-conductor nanopowders is a challenging task. We propose here to combine UPS and UV-Vis spectroscopies in order to get the full description of the electronic band alignment of powder samples, TiO2 rutile and anatase. For UPS measurements, two preparation methods, namely the dropping method and electrophoretic deposition, were used to prepare layers of titania powders on a conducting substrate, ITO or Ag. Both methods lead to comparable results, with a quantitative description of the energy levels from the valence band. Combining these results with the UV-Vis spectra of the same powders enables the determination of the absolute position of the valence band maximum and the conduction band minimum. Combined UPS-UV-Vis spectroscopy provides a better insight into the properties of a powdered material which can differ from single crystal model systems. It can also be used to predict the electronic transfer in mixed phase systems during photocatalytic processes.

fff; International audience; Mo/TiO2 catalysts with atomic dispersion of molybdenum appear active and stable in the gas-phase hydrogenation of CO2. The comparison between various titania materials shows a crucial effect of the support surface structure on the methanol yield. Molybdenum supported at low coverage on rutile titania nanorods is the most active and methanol-selective system. From catalyst characterization by aberration-corrected scanning transmission electron microscopy, near-ambient pressure X-ray photoelectron spectroscopy, diffuse reflectance UV-vis spectroscopy, and temperature-programmed techniques, we suggest that the most active catalysts for methanol production involve atomically-dispersed oxomolybdate species with high reducibility and strong interaction with the rutile support.

The demand of the baking industry has increased steadily in recent years due to which the sector must also face new challenges involving cost, time, and quality of products; it must also achieve optimal profitability rates and contribution margin. According to the aforementioned, it is essential to plan each stage of the processes, the forecast of demand, supply of materials and consumables, production capacity, and distribution and transportation of products. An essential part of these considerations is inventory and warehouse management. Here, we propose a method that makes use of tools such as material requirement planning, economic order quantity, supplier approval, and standardization, which aims to improve the current defective product indicator of 11.43% generated by poor inventory management. After the implementation of the pilot plans, a reduction of 60% was achieved to sustain the effectiveness of the integrating model, the improvement was corroborated with a simulation, obtaining the same results.

International audience; Pt-based materials are widely used as heterogeneous catalysts, in particular for pollutant removal applications. The nature of the active Pt phase responsible for CO oxidation has long been investigated with a view at designing more efficient formulations. The state of Pt has often been proposed to differ depending on experimental conditions, e.g. metallic Pt poisoned with CO being present at lower temperature before light-off, while an oxidized Pt surface prevails above light-off temperature. In stark contrast with all previous reports, we show here that both metallic and oxidized Pt are present in similar proportions under reaction conditions at the surface of ca. 1 nm nanoparticles showing high activity at 30 °C. The simultaneous presence of metallic and oxidized Pt enables a synergy between these phases. The main role of metallic Pt phase is to provide strong adsorption sites for CO, while that of oxidized Pt supposedly supplies reactive oxygen. Our results emphasize the complex dual oxidic-metallic nature of supported Pt catalysts and its evolving nature under reaction conditions, warranting a whole rethink of the mechanism of other reaction and metals, particularly redox and electrochemical reactions.

In Peru, architecture SMEs have a very large gap between technology and information, it is because many times companies only sought to meet the objectives of each project without thinking about the automation of processes, reduction of delivery times or costs of personal. Generating in many situations, delays in deliveries or requests for time extensions (a traditional practice in the country) that directly affects personnel costs and company profits, therefore the proposal seeks to design a monitoring model that allows reducing the times between activities and rework, optimizing deliveries to the client and ensuring the quality of the projects delivered.

This research focuses on the application of the primary tools in industrial engineering with regards to companies and sectors within a country. This analysis focuses on small and medium enterprises in the footwear sector. Small companies currently form a nucleus in the world economy, and thus, research sources include companies in the footwear sector in Lima, Peru. With the aim of continuous improvement, the objective of this research is to implement and control the processes used by the sector through Lean methodology with the following indicators: optimization of the effective time of operators by 13%, production increment by 20%, and finally reduction in reprocessing by 63%. The impact on work is based on changes in machines, stations, functions, tools, and workshop designs to increase productivity in the footwear industry by 23.62%. Therefore, applying operations as tools is essential to effectively analyze and control production.

The beverage manufacturing industry is an extremely competitive sector. Small- and medium-sized businesses usually encounter order fulfillment issues and have high operating costs, negatively affecting their profitability. In this study, we consider a small soft drink production company to design an improvement model. The proposed design is based on the combination of lean manufacturing tools and other tools that may be required depending on the situation. In this sense, the proposed model is based on the 5S methodology, workstation redesigning, process standardization, and reliability-based maintenance. The implementation of the proposed design will increase the efficiency of the production process by 8.8%.

Small and medium toilet manufacturing businesses in Peru face significant problems such as low productivity because of a high rate of production losses. To address this issue, the present study proposes the application of a lean manufacturing technique, such as the Poka-Yoke model, which improves the production flow within the company by implementing a transportation cart with a safety system to help reduce material falls during the manufacturing process. The results showed a 24% increase in productivity and reduction in problems of damaged products that did not meet quality standards, thus preventing their subsequent reprocessing.

The Peruvian export supply is primarily based on the segment of dressings and condiments. This paper seeks to adapt lean manufacturing tools using Poka-Yoke techniques and process standardization, which may align with existing processes to prevent production errors. This combination of tools is expected to reduce the percentage of waste generated throughout the condiment production process. Subsequent to an initial evaluation of the current method combined with the application of both the tools, 11.4% waste reduction was ultimately reported.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. At present, the construction of highways in Andean areas the connect the various most important towns and cities in South America has become has become a key element for its development, since these routes and viaducts allow free access to cover basic needs of education, work, food and health of the population. Much of the land in these areas is clay soils whose behavior is quite unpredictable because they present abrupt volume changes according to the variation of saturation in the soil. People who travel on roads on slopes of this type of soil are at high risk due to the slippage that the slopes suffer each year. The most recent was on April 3, 2020 because of the heavy rainfall that was registered in the area; there was a landslide that affected communication channels in the department of Cajamarca in Peru [1]. In this type of slopes landslides occur when the clayey soil is specifically saturated, because under these conditions the soil is not stable and loses cohesion between its particles, therefore it is important to make slope stability studies taking into account the partially saturated soil. This article presents results of tests allow to recognize the physical characteristics of the clay soil in the province of Chepén in Cajamarca. In addition, the filter paper method is used to elaborate the soil-water characteristic curve and a series of direct shear tests are carried cut at different degrees of saturation. With these results, the partially saturate soil fault surface is constructed that allows visualizing the value of the shear stress of the soil according to the saturation to which it is subjected. This value will be important for calculating the safety factor that the slope floor must have of the resistance shear of the soil according to the saturation, this value will be important for the calculation of the safety factor that the floor of the slope must have so that it does not fall. Therefore, considering this condition of the partially saturated soil in the slope stability analysis provides values of the safety factor that are closer to reality, without the need to carry out the analysis in the most critical condition, such as what it done in classical soil mechanics.

Many parameters influence the photocatalytic production of H2. Identifying and quantifying them is necessary for correct comparison of photocatalysts and right understanding of involved mechanism. In this work, we studied the photocatalytic dehydrogenation of isopropanol with titania-supported ruthenium disulfide. We studied the influence of seven parameters on the photocatalytic activity: the temperature, the composition of the reactive mixture, the mass of the photocatalyst, the flux and the energy of the incident photons, the co-catalyst loading and the nature of the support. Their influence was studied, not only on the rate of hydrogen production (or photon yield) but also on the apparent activation energy and on the pre-exponential factor, deduced from an Arrhenius law. The photon yield as a function of the co-catalyst loading show an optimum of activity. A 6.9 % photon yield was obtained at 0.84 wt% and E p h o t o n s = 3.65 e V . The rate-determining step for the photocatalytic dehydrogenation of the isopropanol with RuS2/TiO2 is, at optimal conditions, the electron transfer from TiO2 to RuS2. The latter is not favored because of the band diagrams of RuS2 and TiO2. The electron transfer can be optimized working with incident photons having a higher energy, thanks to a hot carrier effect observed in RuS2/TiO2.

In the Peruvian market there is a great demand for the improvement of the service and quality of the products, that is why many SMEs look for low-cost alternatives that allow them to optimize their activities and thus be able to assure the quality of the service. The problem is that there are many difficulties when implementing tools or techniques due to high costs or lack of knowledge, therefore a productivity model is proposed focused on six sigma and lean manufacturing methodologies in order to adapt the needs of SMEs with 4 phases can analyze, design, implement and monitor requirements in order to reduce mismanagement of service quality, cost savings and decrease product returns.

In Peru, under the framework of the National Policy for the Modernization of public management by 2021, it is intended that state institutions enter the Civil Service Regime that seeks to continuously improve the public administration in order to avoid disorder in hiring, remuneration excessive, breaches of the rights of the servers, among others, which are currently causing delays and poor service to citizens. For this reason, a management model is proposed that allows integrating the guidelines set forth by the Law of Civil Service and the process improvement techniques that will allow the current situation to be identified, prioritizing which are the critical processes and thus being able to define an improvement plan integrating the different areas within the institution.

International audience; Surface fluorination improves the photocatalytic activity of TiO2, and the influences of various features of fluorinated TiO2 (TiO2–F) have often been discussed in the literature. The present paper addresses the changes induced by surface fluorination on the morphological, structural, surface, and electronic features of TiO2. In particular, X-ray diffraction, specific surface area analysis, and transmission and scanning electron microscopy give evidence that surface fluorination does not affect the structural properties and the morphology of TiO2 nanoparticles. In contrast, fluorination induces changes of surface and electronic properties. Chemical and thermogravimetric analyses show that surface fluorination can reach up to 50% of original Ti–OH surface sites. The surface charge of TiO2 turns more negative upon fluorination, as shown by a shift of the point of zero charge toward lower pH. Electronic properties are deeply characterized by combining diffuse reflectance, X-ray, and UV photoelectron spectroscopies, as well as time-resolved fluorescence spectroscopy, and photoelectrochemical measurements. Results show the presence of intra-band-gap energy states induced by the local interaction of chemisorbed fluorine atoms. Such energy levels are close to the valence band. The unique surface and electronic properties of TiO2–F make it a promising material for the photocatalytic degradation of poorly soluble emerging pollutants such as 1-methylnaphtalene. In particular, TiO2–F demonstrates faster degradation kinetics with respect to both the pristine material and TiO2 P25 used as a benchmark standard.

International audience; Laser engraving is more and more commonly used to write permanent identity features on medical devices. In particular, it is performed on ceramic heads for hip prostheses. Since these components are submitted to high mechanical loading during long periods of time (several years), it is critical to assess the influence of laser engraving on their durability. In the present article, laser marking of zirconia-toughened alumina and alumina-toughened zirconia resulted in an important colour change. It did not affect notably the resistance to hydrothermal ageing, despite important microstructural changes (in particular formation of a zirconia-alumina solid solution layer some tenths of micrometres thick). The formation of this original microstructure was explained by the fast cooling rate after lasing.

NdPO4 has been studied as a model rare earth phosphate catalyst for the dehydration of 2,3-butanediol (2,3-BDO) to butadiene (BD), in order to understand the influence of structure and morphology o...

XPS+ING+LCS:YSC:FRM; International audience; Identifying the causes of the segregation of Pt-based alloy nanoparticles is crucial for the design and operation of the corresponding catalysts and electrodes. This article describes a yet unreported mode of alloy segregation upon exposure to CO. In situ IR studies indicated that Pt-Sn alloy nanoparticles were not stable under (i) H2-free CO at any temperature or (ii) CO/H2 mixtures at temperatures below ca. 450 K. This was rationalized by the ability of Pt to dissociate CO. The oxygen adatoms readily reacted with metallic Sn to form a SnOx species, leading to Pt-Sn segregation, alongside carbon deposition. XPS and XANES analyses confirmed Sn reoxidation. While a contamination by traces of O2 at the sub-ppm level cannot be excluded, the data reported indicate that the structural modifications undergone by the Pt-Sn nanoparticles are more consistent with a reaction involving CO rather than one involving O2. In particular, the XPS analysis after CO exposure revealed an increased fraction of graphitic carbon, while that of oxidized carbon decreased. Thermodynamic calculations indicate that the oxidation of tin by CO, with concomitant carbon formation (Sn + CO → SnO + C) is as favourable as Boudouard reaction (2 CO → CO2 + C) at low temperatures. Alloy stability in the presence of CO must therefore be a concern when CO dissociation is possible and one of the alloyed metal is oxophilic.

The aim of this work is focused on the study of a series of non-traditional catalytic nanomaterials to transform greenhouse CO2 gas into added-value products. We found encouraging results of CO2 hydrogenation activity over sodium titanates with different morphologies. The yield to methanol increases with the increase in the Na incorporated in the nanostructures confirming the proposed mechanism. Samples were prepared at different times of hydrothermal treatment (HTT) with NaOH solutions, and these materials were labeled as Ti-nR-x with x as the hours on the HTT. HRTEM initially showed sphere-shaped nanoparticles in the TiO2 commercial nanopowder, increasing the HTT resulted in morphological changes in which the structures passed from nanosheets and finally to nanorods after 30 h. The X-ray diffraction and Raman spectroscopy results indicated the formation of sodium titanates such as Na2Ti3O7 with short Ti-O bonds and that Na begins to be incorporated into the distorted TiO6 crystalline structure after 5 h of HTT (until 12 wt%). The crystalline and shape transformation resulted in a significant modification on the textural properties passing from 51 m2.g−1 to 150 m2.g−1 and from a pore volume of 0.12 cm3.g−1 to 1.03 cm3.g−1 for Ti-ref and Ti-nR-30 respectively. We also observed differences in the electronic properties as the bandgap presented a blue shift from 3.16 eV on the TiO2 reference nano-powder to 3.44 eV for the Ti-nR-30 calcined sample. This fact coincides with the presence of a more electron-rich state of the Ti4+ and the formation of negative charge layer induced by the presence of Na+ interlayer cations detected by XPS analysis, at the same this helped us to explain the catalytic activity results.

International audience; A series of transition metals sulfides deposited on anatase titania (MSx/TiO2) were prepared by precipitation of transition metals salts with thioacetamide in aqueous medium under reflux. The solids were characterized by XRD, XPS, temperature programmed reduction and transmission electron microscopy. The properties of as obtained catalysts were compared for the photocatalytic hydrogen evolution reaction (PHER) in pure methanol and water-isopropanol mixture. The sequences of PHER activity were compared with electrochemical HER and thiophene hydrodesulfurization (HDS) activity of the corresponding sulfides prepared by the same technique. For PHER, in both alcohols the most active photocatalysts contain hydrogenating sulfides of Co and Ru. However the PHER activity does not follow the same trend as electrocatalytic HER and thiophene HDS. Some sulfides, such as HgS or CuS, show poor activity in HDS and electrocatalytic HER, but have the PHER activity comparable with that of the best samples. This difference suggests that the PHER rate is not merely related to the hydrogen activating properties of the co-catalyst, but is enhanced by the transfer of photogenerated electrons from TiO2 towards the sulfide. The ranking of the co-catalysts and the PHER activity depend also on the nature of the alcohol molecule, the overall PHER rates in water-isopropanol mixture being lower than in methanol.

Silver nanoparticles are currently one of the most studied nanostructured nanomaterials. Because nanoparticle size and dispersion act together in determining a material&rsquo, s physical and chemical properties, there is a continuous quest to develop size-controlled synthesis methods. Nonetheless, the instability of the nanometer-sized particles, which is caused by their tendency to aggregate irreversibly into larger particles, remains a recurrent problem. The use of confining scaffolds, such as the regular system of cages in a crystalline zeolite-type material, is often reported in the literature as an efficient solution to overcome particle migration at the surface. Silver nanoparticles encapsulated in ZSM-5 (Ag@ZSM-5) represent a new generation of adsorbent for Xe enrichment from the atmosphere that is currently being developed at the pilot scale in a Temperature Swing Adsorption (TSA) process. In this study, we have found that the presence of Cl-containing compounds in the air (VOCs) leads to a poisoning of the active silver phase by the formation of silver chloride. By a careful study of process parameters, we have found that most of the chlorine can be removed by heat treatment above 573 K so that the adsorption properties of silver are regenerated. That said, when applying 573 K temperature regeneration at the pilot scale, we observe a very minor but observable decay of xenon adsorption capacity that continues cycle after cycle. The mechanism of capacity decay is discussed in terms of (i) the residual presence of Cl at the surface of silver nanoparticles, (ii) the aggregation of silver nanoparticles into larger particles (sintering mechanism), and (iii) the acceleration of silver particle migration to the surface and sintering.

Modern wound management continues to present new challenges. Many patients elect to forego operative debridement secondary to high risk, fear, cost concerns, and personal ideologies on healing. Although operative debridement has long been a tenet of proper wound care, alternative innovative approaches to wound management must be considered.This case series describes the successful outcomes of 12 patients with dissimilar wounds who were managed with medical-grade honey (active Leptospermum honey [ALH]) as an alternative to surgery.A case series was identified from clinical experience, chart review, and photographic documentation of all patients evaluated by the acute wound care service. To be included, patients had to decline the recommendation of operative debridement or skin grafting, utilize ALH as an alternative to surgery, and have regular follow-up visits.Twelve patients with complex wounds were identified and included in this case series. Five patients were considered high risk for surgery due to comorbidities. Seven patients were at low risk for surgery but desired to avoid operative procedures. The use of ALH facilitated autolytic debridement and healing without surgery or hospital readmission.The properties of ALH include autolytic debridement, bacterial growth inhibition, anti-inflammatory mediation, and cytokine release, making it a viable option for wound management for patients with contraindications to surgery. However, surgical debridement should remain a tenet of wound care in appropriate patients.

International audience; Among the inorganic compounds, many oxides and sulfides are known to be semiconductors. At the crossroads of these two families, oxysulfide MxOySz compounds were much less investigated because they are scarce in nature and complex to synthesize. Amongst them, lanthanide oxysulfide Ln2O2S (Ln = lanthanide) are indirect bandgap semiconductors, with wide gaps, except Ce2O2S. (Gd,Ce)2O2S anisotropic nanoparticles with hexagonal structure were obtained over the whole composition range and exhibit colors varying from white to brown with increasing Ce concentration. Bandgap engineering is thus possible, from 4.7 eV for Gd2O2S, to 2.1 eV for Gd0.6Ce1.4O2S, while the structure is preserved with a slight lattice expansion. Surprisingly, due to the limited thickness of the lamellar nanoparticles, the bandgap of the nanoparticles is direct as validated by density functional theory on slabs. The fine control of the bandgap over a wide range, solely triggered by the cation ratio, is rarely described in the literature and highly promising for further development of this class of compounds. We propose a multi-regime mechanism to rationalize the bandgap engineering over the whole composition range. This should inspire the design of other bimetallic nanoscaled compounds, in particular in the field of visible light photocatalysis.