Facile synthesis of graphene via direct water-sodium dodecylbenzenesulfonate exfoliation

In this study, a mild, one-step electrochemical exfoliation was demonstrated for the synthesis of graphene with the assistance of water and a surfactant, particularly sodium dodecylbenzenesulfonate and sodium dodecyl sulphate. Different types of water-surfactant solutions in different concentrations could influence the exfoliation of graphite rods. From one to several layers of graphene flakes (with a thickness of approximately 1 nm) could be produced directly after sonication. AFM images showed that the flake diameters from this source were typically small. Raman and IR spectroscopic analyses of the dispersed phase suggested that the exfoliation of graphene sheets was accomplished. The flakes were also characterized using field emission scanning electron microscopy, X-ray diffraction, and cyclic voltammetry techniques. Further improvements in this methodology may pave the way to develop green, cost-effective, and large-scale production methods for graphene sheets

Flexible graphene-based supercapacitors: a review

The recent rapid growth in graphene-based supercapacitors has reached the point where there is a need for solid-state devices with physical flexibility, which will be a crucial advantage in modern electronic devices. Herein, we summarize recent developments toward an all solid-state graphene-based flexible supercapacitor. The routes to produce graphene-based electrode materials, along with the typical fabrication techniques for flexible devices, are thoroughly discussed. Furthermore, the structural morphology of the electrode materials is closely related to the electrochemical performance, and the influence of the electrode components on the mechanical flexibility of the fabricated devices is examined. Lastly, a summary of the overall electrochemical properties and current development of the reported devices is presented progressively to predict the future trends toward the realization of an ultimate-performance graphene-based flexible supercapacitor

Impact toughness and ductility enhancement of biodegradable poly(lactic acid)/poly(ε-caprolactone) blends via addition of glycidyl methacrylate

Poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends were prepared via melt blending technique. Glycidyl methacrylate (GMA) was added as reactive compatibilizer to improve the interfacial adhesion between immiscible phases of PLA and PCL matrices. Tensile test revealed that optimum in elongation at break of approximately 327% achieved when GMA loading was up to 3wt%. Slight drop in tensile strength and tensile modulus at optimum ratio suggested that the blends were tuned to be deformable. Flexural studies showed slight drop in flexural strength and modulus when GMA wt% increases as a result of improved flexibility by finer dispersion of PCL in PLA matrix. Besides, incorporation of GMA in the blends remarkably improved the impact strength. Highest impact strength was achieved (160% compared to pure PLA/PCL blend) when GMA loading was up to 3 wt%. SEM analysis revealed improved interfacial adhesion between PLA/PCL blends in the presence of GMA. Finer dispersion and smooth surface of the specimens were noted as GMA loading increases, indicating that addition of GMA eventually improved the interfacial compatibility of the nonmiscible blend

Simulation of decontamination and transmission of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes during handling of raw vegetables in domestic kitchens

Epidemiological data indicates that a large number of foodborne illnesses are attributed to cross-contamination during food preparation in the domestic kitchen. The objectives of this study were to evaluate the efficiency of household washing practices in removing Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis on artificially contaminated lettuce and to determine the transfer rate of these three foodborne pathogens from contaminated lettuce to wash water, tomato, cabbage, and cutting boards during washing and cutting processes. Washing under the running tap water with scrubbing for 60 s was the most effective method in reducing pathogen populations by 1.86 to 2.60 log10 CFU/g. Also, final rinsing and scrubbing practices were found to enhance the efficiency of washing treatment. In this study, the transfer rates of S. Enteritidis, E. coli O157:H7, and L. monocytogenes from cutting board to cabbage and tomato via cutting process (17.5 to 31.7%) were higher (P<0.05) than from wash water to cabbage and tomato (0.8 to 23.0%) during washing treatment. Overall, our findings suggest that wash water and cutting board can be potential vehicles in the dissemination of foodborne pathogens. Therefore, there is a need to promote consumer awareness for proper handling practices in the kitchen to minimise the risk of foodborne infection

Simulation of decontamination and transmission of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes during handling of raw vegetables in domestic kitchens

Epidemiological data indicates that a large number of foodborne illnesses are attributed to cross-contamination during food preparation in the domestic kitchen. The objectives of this study were to evaluate the efficiency of household washing practices in removing Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis on artificially contaminated lettuce and to determine the transfer rate of these three foodborne pathogens from contaminated lettuce to wash water, tomato, cabbage, and cutting boards during washing and cutting processes. Washing under the running tap water with scrubbing for 60 s was the most effective method in reducing pathogen populations by 1.86–2.60 log10 CFU/g. Also, final rinsing and scrubbing practices were found to enhance the efficiency of washing treatment. In this study, the transfer rates of S. Enteritidis, E. coli O157:H7, and L. monocytogenes from cutting board to cabbage and tomato via cutting process (17.5–31.7%) were higher (P < 0.05) than from wash water to cabbage and tomato (0.8–23.0%) during washing treatment. Overall, our findings suggest that wash water and cutting board can be potential vehicles in the dissemination of foodborne pathogens. Therefore, there is a need to promote consumer awareness for proper handling practices in the kitchen to minimise the risk of foodborne infection

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Preparation and characterization of Poly(lactic acid)/ Poly(ɛ-caprolactone)/ Glycidyl Methacrylate blends and the effects of electron beam irradiation on the blends

This research focused on blending of Poly(lactic acid) (PLA) with Poly(ε- caprolactone) (PCL) in order to overcome the brittle character of PLA matrix. Properties of PLA was successfully tuned to ductile however poor compatibility between these polymers limited the extend of improvement. Thus, Glycidyl Methacrylate (GMA) was utilized as interfacial compatibilizer to improve the interfacial compatibility of the non-miscible components. Besides, the effects of electron beam irradiation on mechanical properties of compatibilized blends were studied as well. The properties of PLA/PCL blends were improved significantly by addition of GMA by 3 wt%. FT-IR spectra indicated slight interaction between GMA and PLA matrix, in agreement with the improvement in mechanical properties. Elongation at break of the blend increased dramatically from 17.1% to 327% indicating better dispersion of PCL in PLA matrix as well as improvement interfacial adhesion. Decrease in flexural strength and modulus upon addition of GMA designated that the specimens were tuned from rigid to deformable. Besides, significant increase in impact strength from 418.36 J/m to 802.35 J/m was also recorded upon addition of GMA. Thermal properties of the blends were studied via Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA). TGA revealed addition of 3 wt% GMA resulted slight improvement in thermal stability of the blend. In addition, DMA analysis showed that glass transition temperature (Tg ) of PLA in the blend shifted significantly to a lower temperature region with addition of GMA, indicating improved compatibility of the components. Scanning electron microscopy (SEM) was utilized to study the fracture surface morphology of the blends. The random and fibrous structure of PLA/PCL blend was tuned to a finer dispersion morphology upon addition of GMA.From water absorption analysis, it can be deduced that the addition of GMA influence the water uptake affinity of the blends to slightly higher level. However, the total increment in weight due to water absorption was considered minor (less than 1%). Soil burial degradation analysis revealed that the rate of degradation of PLA was relatively low. Besides, the addition of GMA did not significantly influenced the rate of degradation. Mechanical study on the irradiated specimens showed that the compatibilized blends were still remained ductility upon irradiation up to 10 kGy. Besides, slight increment was recorded on tensile strength when irradiation dosage varied from 10 to 15 kGy. Elongation at break dropped remarkably with increasing irradiation dosage up to 25 kGy, following by gradual decrement in tensile strength and modulus. However, blends added with GMA showed better resistivity upon irradiation, noted by high tensile strength and modulus values were retained upon irradiated at 25 kGy of dosage. FT-IR analysis revealed no shift in wavenumber occurred as a function of irradiation, indicating no interactions occurred. Water absorption analysis showed that irradiated specimens absorbed less water, however soil burial degradation test recorded no enhancement on the rate of degradation of the specimens upon irradiation

Fabrication of carbon-based nanostructured flexible supercapacitor

This research essentially focuses on the fabrication of a carbon-based flexible energy storage devices via the development of highly flexible electrode material. In the first study where polypyrrole/ graphene oxide/ zinc oxide nanocomposite was directly electrodeposited on a nickel foam by an electrodeposition technique, a free-standing flexible supercapacitor was fabricated by sandwiching a potassium hydroxide/ polyvinyl alcohol hydrogel electrolyte between two layers of the as-prepared ternary nanocomposite electrodes. A specific capacitance of 123.8 Fg-1 at 1 Ag-1 was achieved with excellent flexibility. However, the cycling stability of the ternary nanocomposite showed a sensitive behavior towards types of electrolyte used, at which a favorable specific capacitance retention of more than 90.0% using a mild alkaline electrolyte. In order to improve the stability performance, electrospinning technique is employed at which a flexible and conductive nanofiber membranes were fabricated. Initial attempt by introducing graphene oxide to envelop the carbon nanofibers resulted poor electrochemical performance as the effect of pore blockage by graphene oxide. Whereby second attempt with addition of graphene nanoplatlets resulted in enhancement of electrochemical performance, however with in-distinctive trend as the effect of phase separation presence between CNF/ GnP components. Further modification was made at which graphene oxide was functionalized to induce hydrophobicity by using a photo-polymerization approach, at which it was successfully dispersed in the precursor polymeric solution. The electrochemical performance of the reduced graphene oxide-modified carbon nanofibers resulted in a specific capacitance of 140.10 Fg-1 at a current density of 1Ag-1 with capactitance retention of 96.2%, however with a significant increase in charge transfer resistance, which was not favorable in electrochemical devices. A final attempt was made via electrospun polyacrylonitrile membranes with reinforcement of metallic contents, which induced a unique morphology with integration of metal oxides with the polymer structure upon carbonization. When the nanofibers were constructed into a supercapacitor device, a specific capacitance of more than 100 Fg-1 was recorded at 1 Ag-1, along with minimal resistance as compared to any other counterparts, achieved with reinforcement of nickel oxide nanoparticles. Furthermore, the fabricated device retained a capacitive retention of as high as 93.9% even after 2000 cycles of vigorous galvanostatic charging/ discharging process, with a minimal value of 0.05 V voltage drop. Additionally, the device successfully demonstrated excellent flexibility by recording no deviation in performance even subjected to bending and curvatures. These studies concluded that the fabrication of flexible electrode materials is the determining role in the fabrication of a highly flexible energy storage device