Specific Rate Research Articles

Mechanical properties and biocompatibility of multilayer systems based on amorphous SiN:H/SiCN:H layers on Ti6Al7Nb titanium alloy

Surfaces of metallic implants that replace diseased joints are bound to degrade over time under constant mechanical wear and corrosion, caused by the presence of biological fluids. Production of wear particles and toxic metal ions that follows can undermine both implant stability and patient’s health. To counteract this process multiple surface modifications have been proposed in scientific literature, ranging from simple nitriding to protective layers (e.g.: DLC, CN:H) and multilayer systems. This work presents a combined approach to outlined issue, using multi-staged plasma deposition with SiCN:H layer as a key component, realized using the MW CVD (Microwave Chemical Vapour Deposition) system. The study covers chemical characterization by EDS and FTIR analysis and measurements of relevant functional parameters, such as hardness, Young’s modulus, coefficient of friction, specific wear rate and wettability. Additionally, biocompatibility of modified surfaces are tested on MG-63 cells using Alamar Blue assay, flow cytometry and alkaline phosphatase (ALP) assay. Chemical and microscopic studies revealed amorphous cauliflower-like microstructures that have proven to be hydrogenated SiCN/SiN structures. The obtained layers are turned out to be biocompatible (>70 % of cell survival rate), additionally layers based on amorphous SiCN:H boost ALP activity due to combination of their chemistry and mechanical properties.

Iliofemoral Deep Vein Thrombosis With Central Venous Catheter

A central venous catheter is often used when managing patients who need hemodialysis. Venous thrombus formation is often a complication of catheter placement. Most patients with catheter-related thrombus (CRT) are asymptomatic. Gray scale and duplex sonography have a high sensitivity and specificity rate for detecting CRT. This case study presents a patient with a CRT and reviews the structures a sonographer should assess when a patient presents for evaluation of the lower extremity venous system, with an iliofemoral catheter in place.

Electrochemical Performance and Characterisation of Chemically Treated Conductive PLA Fused Deposition Modelling (FDM) Current Collectors within Additively Manufactured (3D-Printed) Symmetric Carbon Supercapacitors

Within the fields of materials science, producing reliable, long-lasting, and efficient energy storage devices to meet the world’s energy needs remains a foremost research goal. 3D-printing (also known as Additive Manufacturing) provides many benefits to this research [1-8], allowing for excellent customization and freedom of design, while eliminating waste material in the manufacturing process. Wearable electronics, medical implants, and the Internet of Things will doubtless benefit from the advantages provided by additive manufacturing.Our previous work compared the electrochemical performances of symmetric carbon-based supercapacitor devices made using two 3D-printing techniques, SLA (stereolithography) and FDM (fused deposition modelling). Though possessing excellent cycle life, the conductive polylactic acid (PLA) FDM printed current collectors suffered from relatively high resistance and poor cyclic voltammetry curves (far from the rectangular shape of ideal electronic double-layer capacitors). This study aims to improve the conductivity of the FDM current collectors via chemically induced surface modification [9]. Both dimethylformamide (DMF) and aqueous potassium hydroxide (KOH) treatments are used for this purpose. The untreated, DMF-treated, and KOH-treated FDM current collectors are loaded with 1:1 by mass single-walled carbon nanotubes and graphene nanoplatelets carbon slurry, placed within stereolithography (SLA) 3D-printed casings [10], and assembled as supercapacitor cells (separated by glass microfiber filter separators soaked in 6 M aqueous KOH electrolyte).This works shows how DMF treatment method results in little change in electrochemical performance compared to the untreated FDM current collector cells, but pre-treatment in a solution of KOH identical to the cell electrolyte markedly improves the current collector conductivity. The KOH treatment provides a tenfold decrease in the FDM current collector resistance, which correlates with the improved cyclic voltammetric response. Galvanostatic charge-discharge tests reveal the effect of these treatments on specific capacitance, charge-discharge response, efficiency, and rate capability for these printed cells. The pre-treatment confirms that the cell electrolyte does not limited long term performance by interacting with the PLA current collector in 3D printed supercapacitor cells and tests using other inorganic active materials will also be shown.

(General Student Poster Award Winner, 3rd Place) Lithium Niobate Coatings on Lithium Iron Phosphate Cathode Materials for Applications in Lithium-Ion Batteries

Lithium-ion batteries have become a crucial tool in countering global fossil fuel reliance; when paired with electric motors, they provide an alternative to petroleum-based energy storage for internal combustion engines. Typical cathode materials used in lithium-ion batteries present a unique set of challenges. Some of the electrochemical materials that have a relatively high performance also have serious impacts on the environment and human health.1 Other materials that lack these specific drawbacks, such as lithium iron phosphate (LFP), face other issues. For example, LFP suffers from a relatively low electrical conductivity and a relatively slow lithium-ion diffusion, both of which affect the general electrochemical performance of this material. These weaknesses can be addressed using coatings applied to LFP nanoparticles. Carbon coatings have already been shown to improve the performance of LFP nanoparticles, but materials with higher ionic conductivities have remained relatively undeveloped.2 By synthesizing a composite coating of both carbon and lithium niobate, further improvements to LFP nanoparticles were sought to enable a wider range of applications for this cathode material.In this work, lithium niobate coatings on carbon coated LFP nanoparticles were synthesized using a low temperature solvothermal method. Lithium niobate coatings have been shown to improve the specific capacity, rate capability, and durability of other cathode materials for lithium-ion batteries.3 Half-cells were fabricated to examine the effect of adding a lithium niobate coating to the carbon coated LFP cathode materials. Electrochemical testing techniques such as galvanostatic cycling and cyclic voltammetry were used to compare the properties and performance of the composite coated LFP relative to the carbon coated LFP. The composite coatings were also characterized using transmission electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. This coating method has resulted in the successful synthesis of lithium niobate coatings on carbon coated LFP nanoparticles with an observed improvement in durability. Goodenough, J. B.; Kim, Y. Challenges for Rechargeable Li Batteries. Mater. 2010, 22 (3), 587–603.Wang, J.; Sun, X. Understanding and Recent Development of Carbon Coating on LiFePO4 Cathode Materials for Lithium-Ion Batteries. Energy Environ. Sci. 2012, 5 (1), 5163–5185.Kim, J. H.; Kim, H.; Choi, W.; Park, M.-S. Bifunctional Surface Coating of LiNbO3 on High-Ni Layered Cathode Materials for Lithium-Ion Batteries. ACS Appl. Mater. Interfaces 2020, 12 (31), 35098–35104.

Electrocatalytic Conversion of Phenol to Cyclohexane Using Pt and Ru-Based Catalysts

The production of renewable fuels has become necessary as fossil fuels continue to deplete.1 Pyrolysis of biomass to liquid fuels has emerged as a promising solution due to the possibility of conversion of high carbon content feedstocks into fuel. Pyrolysis oils, however, struggle from low yields and increased heteroatom content.2 In order to solve this problem a second upgrading step is needed to increase the fuel’s hydrogen content and remove heteroatoms. Conventional oil upgrading through thermochemical processes is an option using high temperatures (>300 °C) and high-pressure hydrogen (10-20MPa).3 Electrochemical upgrading of bio-oils represents a novel avenue for the conversion of bio-oils to usable fuels or commodity chemicals under mild condition which requires milder temperatures (30-80 °C) and generates the hydrogen in situ through the water splitting reaction.3 Though initial results on electrocatalytic upgrading have been promising, few studies report appreciable yields of fully deoxygenated products and the efficiency remains low at high current densities.3 This work focuses on the upgrading of phenol as a bio-oil model compound. ECH of phenol was investigated in a custom electrochemical cell (H-Cell), with a solvent trap for the collection and quantification of volatile organic products. Efficient ECH conversion of phenol to cyclohexane was demonstrated and the primary factors impacting the selective production of cyclohexane were studied. Multiple variables, including catalyst type, electrolyte composition and concentration, and cathodic potential were investigated to determine their influence on ECH reaction rate, selectivity, and efficiency. The results obtained show that lab-synthesized, bi-metallic PtRu-C catalyst results in the highest specific ECH rate of 23.52 mol h-1 g-1 metal in comparison to 19.92 mol h-1 g-1 metal, 15.84 mol h-1 g-1 metal and 4.64 mol h-1 g-1 metal, measured with a commercial PtRu-C and mono-metallic Pt-C and Ru-C catalysts, respectively. In addition, the lab synthesized PtRu-C catalyst achieved > 30% selectivity towards cyclohexane, which is among the highest reported in literature to date. Constant potential experiments showed that the cyclohexane was 4.6% higher at -0.46 V vs Ag/AgCl than -0.28 V vs Ag/AgCl indicating cyclohexane selectivity is weakly dependent on cathodic potential. To improve the mechanistic understanding of phenol ECH, operando Raman spectroscopy was explored, finding strong evidence for cyclohexanone reaction intermediates.References(1) Zhang, X.; Lei, H.; Chen, S.; Wu, J. Catalytic Co-Pyrolysis of Lignocellulosic Biomass with Polymers: A Critical Review. Green Chemistry. 2016. https://doi.org/10.1039/c6gc00911e.(2) Zhang, B.; Zhong, Z.; Min, M.; Ding, K.; Xie, Q.; Ruan, R. Catalytic Fast Co-Pyrolysis of Biomass and Food Waste to Produce Aromatics: Analytical Py-GC/MS Study. Bioresour. Technol. 2015, 189. https://doi.org/10.1016/j.biortech.2015.03.092.(3) Chen, G.; Liang, L.; Li, N.; Lu, X.; Yan, B.; Cheng, Z. Upgrading of Bio-Oil Model Compounds and Bio-Crude into Biofuel by Electrocatalysis: A Review. ChemSusChem. 2021. https://doi.org/10.1002/cssc.202002063. Figure 1

Comparing Effects of Back Diffusion and Membrane Resistance on the Performance of a Low Temperature Electrochemical Hydrogen Pump

“Green” hydrogen produced via electrolysis using electricity from renewable energy sources is seen as a promising energy carrier to aid in the transition from fossil fuels because its production emits no carbon and consumes only water as a reactant. However, the high energy demand required to compress hydrogen to higher energy densities required for efficient transport and storage remains a bottleneck for its deployment1-4. Electrochemical hydrogen pumps (EHPs) are an attractive solution since they operate via isothermal compression and are thus more efficient than typical mechanical compressors which operate adiabatically1,2,5. EHPs also have the advantage of low noise, absence of moving parts, and ability to simultaneously purify hydrogen during compression1-4.In this study, an in-house built EHP test cell with an active geometric area of 25 cm2 was constructed using membrane electrode assemblies (MEA) based on a proton exchange membrane (PEM) and a platinum catalyst. The cell was used to pressurize hydrogen from atmospheric pressure to 10 barg. The net performance of EHPs is a result of the tradeoff between the two major losses that is, back diffusion of H2 and membrane resistance3-5. Thus, we compared the effect of varying temperature, in the range of 30-75°C, on cell performance. Current densities reaching 1.0 A cm-2 (corresponding to a specific hydrogen flow rate of 7.45 mLs min-1 cm-²) were achieved during testing. Linear sweep voltammetry was used to quantify the back diffusion of hydrogen with temperature, see Figure 1(a). Electrochemical impedance spectroscopy was used to determine the series resistance of the EHP. Figure 1(b) shows the increase in voltage with increasing high frequency resistance, whose largest contribution comes from the membrane, with reducing cell temperatures. Stepped chronopotentiometry measurements were used to characterize the overall cell performance. Figure 1 (c) and (d) show the effect of temperature on the polarization curves at a cathode pressure of 5 and 10 barg, respectively, of the EHP operating with an Aquivion E98-09S membrane with 0.25 mg cm-2 Pt per electrode. At 0.5 A cm-2, an applied voltage of 195 mV was required to compress hydrogen at atmospheric pressure in one step to 10 barg operating at 30°C, corresponding to an overall efficiency of 16%. When the cell temperature is raised to 75°C, a lower voltage of 132 mV is required at 0.5 A cm-2 due to the stronger effect of the reduced series resistance that leads to a higher cell efficiency of 27%. This work shows that membrane resistance has a greater effect than back diffusion on the overall EHP performance to pressures of 10 barg.Future work is focused on coupling this EHP with a photovoltaic driven electrolyser and further decreasing the energy demand required to compress hydrogen. References J. Zou, N. Han, J. Yan, Q. Feng, Y. Wang, Z. Zhai, J. Fan, L. Zeng, H. Li, H. Wang., Electrochemical Energy Reviews 2020, 3, 690–729.G. Sdanghi, J. Dillet, S. Didierjean, V. Fierro, G. Maranzana., Fuel Cells 2020, 3, 370-380Y. Hao, H. Nakajima, H. Yoshizumi, A. Inada, K. Sasaki, K. Ito., International Journal of Hydrogen Energy 2016, 41, 13879-13887.M. Ivanova, R. Peters, M. Müller, S. Haas, M. Seidler, G. Mutschke, K. Eckert, P. Röse, S. Calnan, R. Bagacki, R. Schlatmann, C. Grosselindemann, L. Schäfer, N. Menzler, A. Weber, R. Van de Krol, F. Liang, F. Abdi, S. Brendelberger, N. Neumann, J. Grobbel, M. Roeb, C. Sattler, I. Duran, B. Dietrich, C. Hofberger, L. Stoppel, N. Uhlenbruck, T. Wetzel, D. Rauner, A. Hecimovic, U. Fantz, N. Kulyk, J. Harting, O. Guillon., Angewandte Chemie, 2023, 62, e202218850B. Kee, D. Curran, H. Zhu, R. Braun, S. DeCaluwe, R. Kee, S. Ricote., Membranes 2019, 9,77. Figure 1

(Invited) Plasma Reforming of Liquid Hydrocarbons

Engineering systems that more sustainably use our natural resources is central to both reducing the risks associated with CO2 emissions and making the long-term transition to a more circular, sustainable, and electrified economy. In particular, developing electrically driven technologies to leverage the energy density of liquids to produce clean fuels, e.g., H2, without making CO2, could be game changing. Here, we investigate the potential of directly exciting plasmas in liquid hydrocarbons to create multi-phase reaction environments, i.e., environments where plasma (ionized gas), H2, gaseous and liquid hydrocarbons, and solid carbon are all present simultaneously, to produce H2, unsaturated C2s, and carbon. The ultimate target is direct transformation of liquid hydrocarbons to gaseous H2 and solid, easy-to-separate carbon using electricity that can be provided from any source and/or points of use.This talk will focus on our recent experiments to strike and sustain low and high frequency plasma discharges in liquid hydrocarbon jets to simultaneously generate gaseous H2, C2s, and solid carbon at high rates. Preliminary experiments show that (i) input energy is not wasted in simply vaporizing the liquid - so the system’s specific energy input preferentially drives hydrocarbon cracking; (ii) discharge drive frequency and plasma space time have a big effect on the H2 specific energy requirement (SER) and H2 generation rate, respectively; (iii) feedstock chemistry affects the H2 and C2 products observed; (iv) carbon particulates rapidly form in the liquid hydrocarbon, but they can be separated easily; and (v) the SER for H2 production is 25-30 kWhr/kg, roughly two times less than water electrolysis in practice (60 kWhr/kg). Hydrocarbon conversion, reaction rates, and characterization of the plasma (OES, high speed imaging), gas (MS), liquid (GC/MS), and solid phase (SEM, Raman) products as a function of plasma operating conditions (high and low AC drive frequency; liquid-plasma contact time) and hydrocarbon source will be discussed.

Efficacy of weekly dose of 1% atropine for myopia control in Chinese children

PurposeTo assess the effect of weekly 1% atropine use on children’s myopia progression and whether the effect is sustainable.MethodsMedical records of myopic children aged 3–15 years receiving weekly 1% atropine...

Hydrogen Evolution Reaction: Log j0 Versus Work Function Φ As Viewed from Transition State Theory As an Eyring Plot

In 1972, Trasatti correlated the log of the exchange current density (j0) for the hydrogen evolution reaction (HER) with the work functions of 31 metal electrodes to yield two parallel regression lines. [1] The lines are separated by Δ log j0 = 3. Thermodynamically, work function 𝚽 is the energy to remove an electron from a metal to infinity. Perhaps counterintuitively, platinum group metals (PGMs) with the highest 𝚽 sustain the highest j0 values.The elementary, interfacial electron transfer occurs between the electrode and adsorbed hydrogen cation and adsorbed hydrogen atom.H+ ads + e ⇌ H● ads A materials dependent rate expression is developed as follows. [2]The properties of the metal are introduced explicitly into reaction mechanism, characterized by M(e) and M(0), the metal electrode with and without the electron.M(e) + H+ ads ⇄ M(0) + H● ads Classical transition state theory (TST) characterizes the free energy of activation ΔG‡ as the energy difference between the transition state (TS) and the minimum energy of the reactants. The TS forms at equilibrium, where adsorbed hydrogen and metal electrode share the electron.M(e) + H+ ads ⇌ [M ●●● e ●●● Hads]‡ ⇌ M(0) + H● ads Electrochemical potentials set the energy difference in the products and reactant, which sets ΔG‡. Chemical potential (𝞵) difference for the metal without and with the electron define 𝚽. F𝚽 = 𝞵M(0) - 𝞵M(e) F𝚽 is further defined as a chemical free energy that that lowers ΔG‡. F𝚽 is a material specific property that is atypically specified in the rate equation. Because log j0 ∝ - ΔG‡, and chemical free energy F𝚽 lowers ΔG‡, log j0 ∝ F𝚽. Thus, j0 increases exponentially with F𝚽, so PGMs with highest 𝚽 sustain highest j0. Further, the rate expression embeds material specific property 𝚽.The classical Eyring perspective for generic rate constant k’ is k’ = A’ exp[-ΔG‡/RT]. Rate constant is typically determined by varying temperature in a plot of ln k’ versus T-1, where ln k’ = ln A’ - ΔG‡/RT. For isothermal measurements, log j0 is linear with 𝚽 because F𝚽 is a term ΔG‡ chem that is a component in the total ΔG‡. For metals, where 𝚽 > 0, F𝚽 always lowers ΔG‡ for HER; the total activation energy is lowered in proportion to F𝚽. The slopes of log j0 versus 𝚽 is proportional to 𝝰𝚽F𝚽/2.303, where partition coefficient 𝝰𝚽 characterizes ∂ΔG‡/∂𝚽. For the parallel lines in Trasatti’s plot, 𝝰𝚽 = 0.38. The intercepts are independent of 𝚽.The material specific rate expressions derived from classical TST and electrochemical potentials may provide guidance on design of electrocatalysts and provide a path to integration of classical and contemporary modeling of important reaction processes such as HER.

Concerted Formation of Reversibly Precipitated Sulfur Species and Its Importance for Lean Electrolyte Lithium-Sulfur Batteries.

Achieving high energy densities for lithium-sulfur batteries remain elusive. Largely limited by the volume of electrolyte used, lean electrolyte conditions (electrolyte/sulfur mass ratio <3) present enormous challenges that have led to very poor specific capacity and rate performance. Previous studies have identified that the high concentration of polysulfide is responsible for the poor discharge voltage. However, there still lacks sufficient understanding of the processes occurring at lean electrolyte conditions. In this work we uncovered a polysulfide concentration regulating mechanism that operates through the precipitation and redissolution of solid sulfur-based species (reversibly precipitated sulfur species, RPSS). This occurs in a concerted manner in a global sense through the cathode and can be measured using impedance spectroscopy. It was found that the more RPSS that is formed, the higher the energy density of discharge. We propose that high concentration of polysulfide tends to supersaturate, which impeded the formation of RPSS. Employing an electrolyte with low Li ion concentration along with using poorly dissociating lithium salts allowed for more RPSS formation and ultimately enabled discharge at >2.0 V at 0.05 C, at E/S = 2.5, and at room temperature without the use of an engineered cathode.

Effect of biochar filler on improving the power production efficiency of SMFCs

In this paper, the promotion effect of different biochar fillers on the electric generation performance of sedimentary microbial fuel cells (SMFCs) was studied. Three different biochar types were successfully prepared by high temperature pyrolysis and acidification modification technology. In order to evaluate their application value in improving the power generation efficiency of SMFCs, not only the specific surface area and weight loss rate of these biochar were measured. The output voltage, polarization curve and power density curve were also analyzed. The results showed that the specific surface areas of corn stalk, peanut shell and walnut shell were 24.66 m2/g, 3.90 m2/g and 3.67 m2/g, respectively. The SMFCs output voltages of the three biochar fillers were 0.16 V, 0.13 V and 0.19 V, respectively. The power density of SMFCs was higher than that of blank group (0.01 V). Moreover, the power density of SMFCs of corn stalk filler is as high as 91 mW/m3, which is nearly twice that of blank group (48 mW/m3). And the internal resistance of SMFC with corn stalk fillers (3981.63 Ω) is also lower than that of the other groups. It can be seen that biochar fillers can further optimize the power generation performance of sedimentary microbial fuel cells, and provide a new choice for the development direction of low-cost, green and clean SMFC.

Analyzing the impact of TiO2 filler on the wear characteristics of flax fiber-reinforced epoxy composite using the Taguchi approach

Purpose This study aims to investigate the impact of titanium oxide (TiO2) filler on the coefficient of friction (COF) and specific wear rate (SWR) in flax fiber reinforced epoxy composites (FFRCs) under abrasive wear conditions utilizing the Taguchi approach. The primary objective is to enhance wear resistance and promote the development of sustainable materials for various applications. Design/methodology/approach Epoxy/flax composites with varying TiO2 filler content (0–8 wt%) are fabricated through the hand layup method. Subsequently, wear testing is conducted following ASTM G99-05 standards. The Taguchi design of experiments (DOE) and analysis of variance (ANOVA) are utilized for statistical analysis. Findings Results indicate a significant improvement in abrasive wear properties with the incorporation of TiO2 filler. The COF is found to be most influenced by the normal load (55.19%), followed by grit size, wt% TiO2 filler and sliding distance. SWR is found to be most influenced by the grit size (42.92%), followed by wt% TiO2, normal load and sliding distance. Notably, the Taguchi model aligns well with experimental results, demonstrating its efficacy in predicting the abrasive wear behavior of FFRCs. Originality/value This research introduces a novel hybrid composite that combines TiO2 filler and flax fibers, showcasing their potential to enhance the tribological properties of epoxy composites. The study offers valuable insights into optimizing abrasive wear test variables in natural fiber-reinforced composites using Taguchi DOE and ANOVA, crucial for improving the performance of sustainable materials in engineering applications.

Nanoscale synergy: Optimizing energy storage with SnO2 quantum dots on ZnO hexagonal prisms for advanced supercapacitors

Abstract Electrode materials comprising SnO2 quantum dots embedded within ZnO hexagonal prisms were successfully synthesized for building cost-effective energy-storage devices. Extensive structural and functional characterizations were performed to assess the electrochemical performance of the electrodes. SEM–EDS results confirm a uniform distribution of SnO2 quantum dots across ZnO. The integration of SnO2 quantum dots with ZnO hexagonal prisms markedly improved the electrochemical behavior. The analysis of electrode functionality conducted in a 3 M KOH electrolyte revealed specific capacitances of 949.26 and 700.68 F g⁻1 for SnO2@ZnO and ZnO electrodes, respectively, under a current density of 2 A g⁻1. After undergoing 5,000 cycles at a current density of 15 A g⁻1, the SnO2@ZnO and ZnO electrodes displayed impressive cycling stability, maintaining specific capacitance retention rates of 89.9 and 92.2%, respectively. Additionally, a symmetric supercapacitor (SSC) device constructed using the SnO2@ZnO electrode showcased exceptional performance, exhibiting a specific capacitance of 83 F g⁻1 at 1.2 A g⁻1. Impressive power and energy densities were achieved by the device, with values reaching 2,808 and 70.2 W kg⁻1, respectively. Notably, the SnO2@ZnO SSC device maintained a capacity preservation of 75% throughout 5,000 galvanostatic charge–discharge sequences. The outcomes highlight the potential of SnO2@ZnO hexagonal prisms as candidates for energy-storage applications, offering scalability and cost-effectiveness. The proposed approach enhances the electrochemical performance while ensuring affordability, facilitating the creation of effective and financially feasible energy storage solutions.

Do Surgeons Experience Moral Dissonance When There Is Misalignment Between Evidence and Action? A Survey and Scenario-based Study.

Moral dissonance is the psychological discomfort associated with a mismatch between our moral values and potentially immoral actions. For instance, to limit moral dissonance, surgeons must develop a rationale that the potential for benefit from performing surgery is meaningfully greater than the inherent harm of surgery. Moral dissonance can also occur when a patient or one's surgeon peers encourage surgery for a given problem, even when the evidence suggests limited or no benefit over other options. Clinicians may not realize the degree to which moral dissonance can be a source of diminished joy in practice. Uncovering potential sources of moral dissonance can help inform efforts to help clinicians enjoy their work. In a scenario-based experiment performed in an online survey format, we exposed musculoskeletal specialists to various types of patient and practice stressors to measure their association with moral dissonance and asked: (1) What factors are associated with the level of pressure surgeons feel to act contrary to the best evidence? (2) What factors are associated with the likelihood of offering surgery? We performed a scenario-based experiment by inviting members of the Science of Variation Group (SOVG; an international collaborative of musculoskeletal surgeons that studies variation in care) to complete an online survey with randomized elements. The use of experimental techniques such as randomization to measure factors associated with specific ratings makes participation rate less important than diversity of opinion within the sample. A total of 114 SOVG musculoskeletal surgeons participated, which represents the typical number of participants from a total of about 200 who tend to participate in at least one experiment per year. Among the 114 participants, 94% (107) were men, 49% (56) practiced in the United States, and 82% (94) supervised trainees. Participants viewed 12 scenarios of upper extremity fractures for which surgery is optional (discretionary) based on consensus and current best evidence. In addition to a representative age, the scenario included randomized patient and practice factors that we posit could be sources of moral distress based on author consensus. Patient factors included potential sources of pressure (such as "The patient is convinced they want a specific treatment and will go to a different surgeon if they don't get it") or experiences of collaboration (such as "The patient is collaborative and involved in decisions"). Practice factors included circumstances of financial or reputational pressure (such as "The practice is putting pressure on you to generate more revenue") and factors of limited pressure (such as "Your income is not tied to revenue"). For each scenario, the participant was asked to rate both of the following statements on a scale from 0 to 100 anchored with "I don't feel it at all" at 0, "I feel it moderately" at 50, and "I feel it strongly" at 100: (1) pressure to act contrary to best evidence and (2) likelihood of offering surgery. Additional explanatory variables included surgeon factors: gender, years in practice, region, subspecialty, supervision of trainees, and practice setting (academic/nonacademic). We sought factors associated with pressure to act contrary to evidence and likelihood of offering surgery, accounting for potential confounding variables in multilevel mixed-effects linear regression models. Accounting for potential confounding variables, greater pressure to act contrary to best evidence was moderately associated with greater patient despair (regression coefficient [RC] 6 [95% confidence interval 2 to 9]; p = 0.001) and stronger patient preference (RC 4 [95% CI 0 to 8]; p = 0.03). Lower pressure to act contrary to evidence was moderately associated with surgeon income independent of revenue (RC -6 [95% CI -9 to -4]; p < 0.001) and no financial benefit to operative treatment (RC -6 [95% CI -8 to -3]; p < 0.001). Marketing concerns were the only factor associated with greater likelihood of offering surgery (RC 6 [95% CI 0 to 11]; p = 0.04). In this scenario-based survey experiment, patient distress and strong preferences and surgeon financial incentives were associated with greater surgeon feelings of moral dissonance when considering discretionary fracture surgery. To support enjoyment of the practice of musculoskeletal surgery, we recommend that surgeons, surgery practices, and surgery professional associations be intentional in both anticipating and developing strategies to ameliorate potential sources of moral dissonance in daily practice.

Prevalence and genotype distribution of human papillomavirus infection among 66000 women from 2014 to 2023 in the plateau region of Southwest China

BackgroundPersistent infection with high-risk human papillomavirus (HR-HPV) plays a key role in the onset of cervical cancer. This study was designed to examine the epidemiological trends and genotype distribution of HPV from 2014 to 2023 in the plateau region of Southwest China.MethodsThe findings could offer valuable insights for clinical screening of cervical cancer and the formulation of HPV vaccination policies. This retrospective study analyzed 66,000 women who received HPV-DNA testing at the First People’s Hospital of Qujing, Yunnan, China, between 2014 and 2023. The cohort consisted of 33,512 outpatients, 3,816 inpatients, and 28,672 individuals undergoing health examinations. Cervical cells were collected for DNA extraction, and PCR amplification along with Luminex xMAP technology were used to detect 27 HPV genotypes. The data analysis was conducted using GraphPad Prism and IBM SPSS Statistics 27 software.ResultsThe overall HPV infection rate at the First People’s Hospital of Qujing declined from 24.92% in 2014 to 16.29% in 2023, averaging 16.02%. Specific infection rates were 18.50% among outpatients, 12.97% among inpatients, and 13.53% for health examination attendees. The predominant high-risk HPV genotypes identified were HPV52 (2.61%), HPV16 (2.06%), HPV58 (1.81%), HPV53 (1.55%), and HPV39 (1.09%). Meanwhile, the most frequent low-risk HPV genotypes were HPV6 (1.30%), HPV61 (1.21%), and HPV11 (0.85%). In HPV-positive cases, the distribution of single, double, triple, and quadruple or more infections were 79.90%, 15.17%, 3.59%, and 1.33%, respectively. The proportions of pure LR-HPV, pure HR-HPV, and mixed infections were 22.16%, 67.82%, and 10.02%, respectively. Age-specific analysis revealed a bimodal distribution of HPV infection, with the infection rate rapidly decreasing from 44.02% in the ≤ 19 age group to 19.55% in the 20–29 age group and 13.84% in the 30–39 age group, followed by a gradual increase to 14.64% in the 40–49 age group, 16.65% in the 50–59 age group, and 22.98% in the ≥ 60 age group. The coverage rates of the three available vaccines are all below 50%. The results of this study indicated a declining trend in HPV prevalence in the plateau region of Southwest China over the period from 2014 to 2023, especially in the reduction of genotypes targeted by vaccines.ConclusionThere were significant variations in the genotypes prevalent among different age groups, years, and patient sources within the same region. The underwhelming vaccination rates emphasize the critical need for developing either a multivalent vaccine or a personalized vaccine that targets the HPV genotypes common in the Chinese population. Furthermore, vaccinating adolescents to curb HPV infection and ensuring regular cervical cancer screenings for postmenopausal women are crucial steps.

Advancing stroke patient care: a network meta-analysis of dysphagia screening efficacy and personalization.

The increasing incidence of stroke globally has led to dysphagia becoming one of the most common complications in stroke patients, with significant impacts on patient outcomes. Accurate early screening for dysphagia is crucial to avoid complications and improve patient quality of life. Included studies involved stroke-diagnosed patients assessed for dysphagia using bedside screening tools. Data was sourced from Embase, PubMed, Web of Science, Scopus, and CINAHL, including publications up to 10 December 2023. The study employed both fixed-effect and random-effects models to analyze sensitivity, specificity, positive predictive value (PPV), and Negative Predictive Value (NPV), each with 95% confidence intervals. The random-effects model was particularly utilized due to observed heterogeneity in study data. From 6,979 records, 21 studies met the inclusion criteria, involving 3,314 participants from 10 countries. The analysis included six assessment tools: GUSS, MASA, V-VST, BSST, WST, and DNTA, compared against gold-standard methods VFSS and FEES. GUSS, MASA, and V-VST showed the highest reliability, with sensitivity and specificity rates of 92% and 85% for GUSS, 89% and 83% for MASA, respectively. Heterogeneity among studies was minimal, and publication bias was low, enhancing the credibility of the findings. Our network meta-analysis underscores the effectiveness of GUSS, MASA, and V-VST in dysphagia screening for stroke patients, with high sensitivity and specificity making them suitable for diverse clinical settings. BSST and WST, with lower diagnostic accuracy, require more selective use. Future research should integrate patient-specific outcomes and standardize methodologies to enhance dysphagia screening tools, ultimately improving patient care and reducing complications. https://www.crd.york.ac.uk/PROSPERO/#recordDetails.

Superficially activating strategies to elevate the supercapacitor performance of nano-cube nickel cobalt-Prussian blue

Prussian Blue Analogs (PBA) has good application potential in supercapacitors due to their unique microstructure characteristics. Nevertheless, the limited conductivity of these materials poses a significant obstacle to their widespread application as electrodes in supercapacitors. Herein, the conductivity of NiCo-PBA is enhanced through the implementation of three surface treatment methods, namely sulfidizing, selenizing and phosphating, and then the explicit electrochemical performance of NiCo-PBA was elevated. In addition, the P-NiCo-PBA//AC ASC occupies the best energy density (48.90 Wh kg−1/42.16 Wh kg−1) at a certain power density (1947.38 W kg−1/9545.10 W kg−1) compared to the NiCo-PBA//AC ASC, S-NiCo-PBA//AC ASC and Se-NiCo-PBA//AC ASC, and the specific capacitance retention rate of P-NiCo-PBA//AC ASC after 10,000 cycles is 88.25%. The phosphating strategy outperforms sulfidizing and selenizing strategies in enhancing the performance of nanocube-like NiCo-PBA supercapacitors. The accomplishment significantly broadens the potential applications of PBA-based materials as electrodes for supercapacitors.

Leveraging the dynamics of microalgal CO2 capture to estimate the maximum inherent photosynthetic potential

AbstractBACKGROUNDNatural photosynthesis, utilizing intelligent molecular machinery to harness sunlight, stands as the benchmark for efficient energy generation. Despite its high quantum efficiency compared to synthetic methods, challenges persist due to dynamic nutritional and light requirements in plant, microalgae, and cyanobacteria‐driven processes. Reported microalgae CO2 uptake rates rely on biomass dry cell weight measurement after certain incubation period and systematic study of required CO2 concentrations for optimal photobioreactor operation remaining unexplored. This research is thus aimed at evaluating the critical dissolved CO2 (Ccrit ∙ CO2) concentration and specific CO2 uptake rates (SCUR) of Chlorella minutissima (CM) culture in the presence of surplus light and other nutrients by online monitoring and measuring the dynamic CO2 uptake rates which will help in maintaining the optimal rate of CO2 delivery for continuous cultivation of microalgae while minimizing the escape of CO2.RESULTSDissolved Ccrit ∙ CO2 was determined to be in the range of 16–20 mg/L, and the maximum SCUR in BBM (Bold Basal Medium) was found to be 0.73 mg CO2 (mg dcw ∙ h)−1. Interestingly, this SCUR value is nearly three times greater than that of the most efficient in vitro artificial photosynthetic novel pathway reported so far.CONCLUSIONFrom the calculated SCUR values, it may be noted that 9.6 g of biomass can be obtained from 1 g of microalgal inoculum in a day, thereby setting a benchmark for the scientists working in the areas of bioprocess engineering, synthetic biology, and metabolic engineering to comply. © 2024 Society of Chemical Industry (SCI).

Discrimination of Lung Cancer and Benign Lung Diseases Using BALF Exosome DNA Methylation Profile.

Benign lung diseases are common and often do not require specific treatment, but they pose challenges in the distinguishing of them from lung cancer during low-dose computed tomography (LDCT). This study presents a comprehensive methylation analysis using real-time PCR for minimally invasive diagnoses of lung cancer via employing BALF exosome DNA. A panel of seven epigenetic biomarkers was identified, exhibiting specific methylation patterns in lung cancer BALF exosome DNA. This panel achieved an area under the curve (AUC) of 0.97, with sensitivity and specificity rates of 88.24% and 97.14%, respectively. Each biomarker showed significantly higher mean methylation levels (MMLs) in both non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) compared to non-cancer groups, with fold changes from 1.7 to 13.36. The MMLs of the biomarkers were found to be moderately elevated with increasing patient age and smoking history, regardless of sex. A strong correlation was found between the MMLs and NSCLC stage progression, with detection sensitivities of 79% for early stages and 92% for advanced stages. In the validation cohort, the model demonstrated an AUC of 0.95, with 94% sensitivity and specificity. Sensitivity for early-stage NSCLC detection improved from 88.00% to 92.00% when smoking history was included as an additional risk factor.

Strain rate dependence of mechanical behavior in an AlSi10Mg alloy with different states fabricated by laser powder bed fusion

The strain rate dependence of mechanical behavior in an AlSi10Mg alloy with different states fabricated by laser powder bed fusion (LPBF) was investigated systematically via thermodynamic calculations, microstructure characterization and mechanical characteristic evaluation in the present study. The results show that there is a close relationship among the material state, microstructure and dynamic mechanical behavior. Before tensile deformation, the as-built specimen possesses a fine equiaxed grain structure and a typical cellular structure surrounded by continuously distributed particles; the annealed specimen has coarser equiaxed grain structures and particles, but no cellular structure is present. Both the as-built and annealed specimens exhibit weak strain rate sensitivity, and the strain rate sensitivity parameters are 0.01 and 0.024, respectively. Under specific strain rate conditions, the as-built specimen has a higher strength and lower elongation than the annealed specimen. After tensile deformation, there is a significant increase in the dislocation density. Independent of the material state, the dislocation density increases with increasing strain rate. Compared with the as-built specimen, the annealed specimen has a stronger strain rate sensitivity because of the greater dislocation density variation.