Search

Background: Maximizing survival for patients with primary cutaneous melanomas (melanomas) depends on an early diagnosis and appropriate management. Several new drugs have been shown to improve survival in high-risk melanoma patients. Despite well-documented guidelines, many patients do not receive optimal management, particularly when considering patient age. Objective: to provide an update on melanoma management from the time of the decision to biopsy a suspicious skin lesion. Methods: We reviewed melanoma-management research published between 2018 and 2023 and identified where such findings impact and update the management of confirmed melanomas. Pubmed, Google Scholar, Ovid and Cochrane Library were used as search tools. Results: We identified 81 publications since 2017 that have changed melanoma management; 11 in 2018, 12 in 2019, 10 in 2020, 12 in 2021, 17 in 2022 and 18 in 2023. Discussion: Delayed or inaccurate diagnosis is more likely to occur when a partial shave or punch biopsy is used to obtain the histopathology. Wherever feasible, a local excision with a narrow margin should be the biopsy method of choice for a suspected melanoma. The Breslow thickness of the melanoma remains the single most important predictor of outcome, followed by patient age and then ulceration. The BAUSSS biomarker, (Breslow thickness, Age, Ulceration, Subtype, Sex and Site) provides a more accurate method of determining mortality risk than older currently employed approaches, including sentinel lymph node biopsy. Patients with metastatic melanomas and/or nodal disease should be considered for adjuvant drug therapy (ADT). Further, high-risk melanoma patients are increasingly considered for ADT, even without disease spread. Invasive melanomas less than 1 mm thick are usually managed with a radial excision margin of 10 mms of normal skin. If the thickness is 1 to 2 mm, select a radial margin of 10 to 20 mm. When the Breslow thickness is over 2 mm, a 20 mm clinical margin is usually undertaken. In situ melanomas are usually managed with a 5 to 10 mm margin or Mohs margin control surgery. Such wide excisions around a given melanoma is the only surgery that can be regarded as therapeutic and required. Patients who have had one melanoma are at increased risk of another melanoma. Ideal ongoing management includes regular lifelong skin checks. Total body photography should be considered if the patient has many naevi, especially when atypical/dysplastic naevi are identified. Targeted approaches to improve occupational or lifestyle exposure to ultraviolet light are important. Management also needs to include the consideration of vitamin D supplementary therapy. [ABSTRACT FROM AUTHOR]

Palladium-based catalytic membrane reactors (CMRs) effectively remove H2 to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H2, CO and CO2. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H2O, CO2 and H2. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H2 and induce higher methane and CO conversions while yielding ultrapure H2 and compressed CO2 ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H2 permeance and purity, high CH4 conversion levels and reduced CO yields. [ABSTRACT FROM AUTHOR]

Ultrafiltration membranes, that respond to an external magnetic field and local temperature have been developed. Surface-initiated activator-generated electron transfer (AGET) atom transfer radical polymerization (ATRP) has been used to graft poly(N-isopropylacrylamide) (PNIPAm) from the surface of 300 kDa regenerated cellulose membranes. The polymerization initiator was selectively attached to the entire membrane surface, only the outer membrane surface or only the inner pore surface. A superparamagnetic nanoparticle was attached to the end of the polymer chain. The DI water flux as well as the flux and rejection of bovine serum albumin were investigated in the absence and presence of a 20 and 1000 Hz oscillating magnetic field. In an oscillating magnetic field, the tethered superparamagnetic nanoparticles can cause movement of the PNIPAm chains or induce heating. A 20 Hz magnetic field maximizes movement of the chains. A 1000 Hz magnetic field leads to greater induced heating. PNIPAm displays a lower critical solution temperature at 32 °C. Heating leads to collapse of the PNIPAm chains above their Lower Critical Solution Temperature (LCST). This work highlights the versatility of selectively grafting polymer chains containing a superparamagnetic nanoparticle from specific membrane locations. Depending on the frequency of the oscillating external magnetic field, membrane properties may be tuned. [ABSTRACT FROM AUTHOR]

Wastewater from the oil industry can be considered a dangerous contaminant for the environment and needs to be treated before disposal or re-use. Currently, membrane separation is one of the most used technologies for the treatment of produced water. Therefore, the present work aims to study the process of separating oily water in a module equipped with a ceramic membrane, based on the Eulerian–Eulerian approach and the Shear-Stress Transport (SST k-ω) turbulence model, using the Ansys Fluent® 15.0. The hydrodynamic behavior of the water/oil mixture in the filtration module was evaluated under different conditions of the mass flow rate of the fluid mixture and oil concentration at the entrance, the diameter of the oil particles, and membrane permeability and porosity. It was found that an increase in the feed mass flow rate from 0.5 to 1.5 kg/s significantly influenced transmembrane pressure, that varied from 33.00 to 221.32 kPa. Besides, it was observed that the particle diameter and porosity of the membranes did not influence the performance of the filtration module; it was also verified that increasing the permeability of the membranes, from 3 × 10−15 to 3 × 10−13 m2, caused transmembrane pressure reduction of 22.77%. The greater the average oil concentration at the permeate (from 0.021 to 0.037 kg/m3) and concentrate (from 1.00 to 1.154 kg/m3) outlets, the higher the average flow rate of oil at the permeate outlets. These results showed that the filter separator has good potential for water/oil separation. [ABSTRACT FROM AUTHOR]

The application of pulsed electric field (PEF) in electrodialysis has been proven to be efficient for a number of effects: increasing mass transfer rate, mitigation of scaling and fouling, reducing water splitting. Recently, the improvement of the membrane permselectivity for specific counterions was discovered experimentally by the group of Laurent Bazinet (N. Lemay et al. J. Memb. Sci. 604, 117878 (2020)). To better understanding the effect of PEF in electrodialysis, simulations were performed using a non-stationary mathematical model based on the Nernst–Planck and Poisson equations. For the first time, it was not only the condition used when the current density is specified but also the condition when the voltage is set. A membrane and two adjacent diffusion layers are considered. It is shown that when applying the regime used by Lemay et al. (the same current density in conventional continuous current (CC) mode and during the pulses in PEF mode), there is a significant gain in specific permselectivity. It is explained by a reduction in the membrane concentration polarization in PEF mode. In the CC mode of electrodialysis, increasing current density leads to a loss in specific permselectivity: concentration profiles in the diffusion layers and membrane are formed in such a way that ion diffusion reduces the migration flux of the preferentially transferred ion and increases that of the poorly transferred ion. In PEF mode, the concentration profiles are partially restored during the pauses when the current is zero. However, if a different condition is used than the condition applied by Lemay et al., that is, when the same average current density is applied in both the PEF and CC modes, there is no gain in specific permeability. It is shown that within the framework of the applied mathematical model, the specific selectivity depends only on the average current density and does not depend on the mode of its application (CC or PEF mode). [ABSTRACT FROM AUTHOR]