•Heterogenous crosslinking reaction of HA and HA-CNF films using di-isocyanate.•Bacteriostatic properties of HA depend on molecular weight.•In vitro antimicrobial activity of high molecular weight ...HA.
Biofilm-related infections and contamination of biomaterials are major problems in the clinic. These contaminations are frequently caused by Staphylococcus aureus and are a pressing issue for implantable devices, catheters, contact lenses, prostheses, and wound dressings. Strategies to decrease contamination and biofilm related infections are vital for the success of implantable biomaterials. In this context, hyaluronic acid (HA), a naturally derived carbohydrate polymer, known to be biocompatible, degradable, and immunomodulatory, has shown some antimicrobial activity effects. Due to its poor structural stability, crosslinking strategies, and the incorporation of reinforcing fibres in HA gels is required to produce tailored gels for varying applications. Whilst carbon-based reinforcing materials, such as carbon nanofibers (CNF), present some intrinsic antimicrobial activity related to their high surface area, herein, a crosslinking strategy to enhance the mechanical properties and regulate the rate of degradation of HA is presented. We utilise bis-(β-isocyanatoethyl) disulphide (BIED) as the crosslinker with the gel reinforced using 0.25 wt% CNF. The effects of CNF and BIED on the structural, mechanical, thermal, and swelling behaviour are examined. These new HA derivatives exhibit excellent mechanical properties and are capable of withstanding physiological stresses in vivo. Antimicrobial activity of the HA derivatives were tested against Staphylococcus aureus and the results reveal antibacterial effect. These carbohydrate based materials have potential application on surfaces within clinical settings where staphylococcal contamination is currently an issue.
As fossil fuel resources dwindle and new regulations for a cleaner and safer environment come on stream, there is growing interest in developing new sustainable feedstocks for future fuels, ...chemicals, polymers and fibers. Therefore materials research is ever more focused on the production of green or bio-based materials and their composites. Lignocellulosic biomass has become the feedstock of choice for these new materials as cellulose and lignin are the most abundant biopolymers on the planet. Lignin is a phenolic macromolecule, the principal biological source of aromatic structures, with a complex structure which varies depending on plant species and its isolation process. Despite its high carbon content and its potential as a raw material, lignin remains underutilised. Between 40 and 50 million tons of lignin are produced worldwide per year; while some is being used for low- and medium-value applications, most is currently treated as a non-commercialized by-product or as low value fuel to produce energy. However, with the emergence of biorefinery projects larger amounts of lignin with the potential for valorisation are being produced. Here, we summarise some of the latest developments in the field.
The use of carbon fibre (CF)-based composites is of growing global importance due to their application in high-end sectors such as aerospace, automotive, construction, sports and leisure amongst ...others. However, their current high production cost, high carbon footprint and reduced production capability limit their use to high-performance and luxury applications. Approximately 50% of the total cost of CF production is due to the thermal conversion of polyacrylonitrile (PAN) precursor fibre (PF) to CF as it involves the use of high energy consumption and low heating efficiency in large furnaces. Looking at this scenario, this study proposes in the present study to use microwave (MW) heating to convert PF to CF. This is scientifically and technologically challenging since PF does not absorb microwave energy. While MW plasma has been utilised to carbonise fibres, it is the high temperature from the plasma that does the carbonisation and not the MW absorption of the fibres. Therefore, for the first time, this research shows how carbonisation temperatures of >1000 °C can be reached in a matter of seconds through the use of a novel microwave (MW) susceptor nanocoating methodology developed via a layer-by-layer assembly of multiwall carbon nanotubes (MWCNTs) on the PF surface. Remarkably, these CFs can be produced in an inexpensive domestic microwave and exhibit mechanical performance equivalent to CF produced using conventional heating. Additionally, this study provides a life cycle and environmental impact analysis which shows that MW heating reduces the energy demand and environmental impact of lignin-based CF production by up to 66.8% and 69.5%, respectively.
Graphical Abstract
The yields of 2,8‐dihalo analogues of Tröger's base in the condensation between 4‐haloanilines and paraformaldehyde was found to be highly sensitive to the crucial reaction parameters of scale, ...stoichiometry and temperature. The reaction conditions were optimized allowing for the semi‐large scale synthesis of the 2,8‐diiodo‐ (2) and 2,8‐dibromo‐ (3) analogues, respectively.
Zusammenfassung
Hintergrund
Die chirurgische Weiterbildung steht vor der anspruchsvollen Aufgabe, technische Fortschritte und Patientensicherheit in Einklang zu bringen, insbesondere im Kontext der ...geplanten Krankenhausreform. Zusätzlich stellen der Generationswechsel und veränderte Ansprüche der Generationen Y und Z an den Arbeitsplatz weitere Herausforderungen dar. Um diesen Anforderungen gerecht zu werden, hat die Berlin-Brandenburgische Chirurgische Gesellschaft (BCG) während der „Neuhardenberger Gespräche“ eine strukturierte Diskussion initiiert und ein Positionspapier erarbeitet.
Methodik
Im Rahmen der Neuhardenberger Gespräche fanden vier Sitzungen mit Impulsvorträgen und Diskussionen statt. Auf Grundlage der Hauptdiskussionspunkte wurden anschließend Thesen und Positionen erstellt, über die digital abgestimmt wurde.
Ergebnisse
Die Resultate zeigen einen klaren Konsens für flexible Arbeitszeitmodelle, frühere Spezialisierungsmöglichkeiten und die Integration externer Rotationen in die chirurgische Weiterbildung. In Bezug auf Talentakquisition und Frührekrutierung von Weiterbildungsassistent*innen zeigte sich ein eindeutiger Konsens für die Förderung von Mitarbeiterengagement und strukturierte Frührekrutierung von Studierenden. Es herrschte Einigkeit hinsichtlich der Einführung von Weiterbildungsverbänden als wirksames Mittel, um eine hochwertige chirurgische Weiterbildung zu gewährleisten.
Diskussion
Einer der zentralen Punkt in den Diskussionen war, dass eine hochwertige chirurgische Weiterbildung nur in Weiterbildungsverbänden realisierbar sein wird, insbesondere vor dem Hintergrund der anstehende Krankenhausreform. Die BCG plant die Ausarbeitung eines modularen Weiterbildungsverbands, um die chirurgische Weiterbildung in Berlin/Brandenburg zukunftsfähig zu gestalten.
There are limited data on the long-term safety and efficacy of drug-eluting stents (DES) implantation in patients with stable angina referred for elective percutaneous coronary intervention (PCI) of ...chronic total occlusion (CTO). We therefore aim to investigate whether DES compared with bare-metal stent (BMS) implantation improves long-term outcomes after successful recanalization of single CTO.
A total of 345 consecutive patients who underwent successful recanalization of single CTO and received DES or BMS in the Cardioangiology Laboratories of the Medical University of Gdansk between January 1, 2006 and December 31, 2010 were included in the CTO Registry database. We compared the 1-year and long-term clinical outcomes of 137 consecutive patients who underwent PCI for CTO and DES implantation with outcomes of 208 patients after successful CTO treatment with BMS implantation. The median follow-up was 22.6 ± 3 months (21.0 ± 3.9 months for DES vs 23.6 ± 1.5 months for BMS; P<.001). The primary endpoints included a composite of all-cause death and non-fatal myocardial infarction (MI) and composite safety endpoint of major adverse cardiovascular events (MACEs), including death, MI and symptom-driven target lesion revascularization (TLR). A secondary endpoint was a symptom-driven TLR.
After stent implantation we noted lower rates of the composite endpoint at 1-year (9.5% DES vs 18.3% BMS; P=.01) and long-term follow-up (11.7% DES vs 21.1% BMS; P=.02) due to fewer episodes of TLR in the DES group (5.1% DES vs 14.4% BMS; P=.006 at 1-year follow-up; 7.3% DES vs 14.4% BMS; P=.04 at long-term follow-up). No significant differences were documented in the rate of death, MI, or in-stent thrombosis between investigated subsets. After adjusting for patient and procedural characteristics as well as propensity, BMS implantation remained independently associated with an increased hazard of 1-year MACE (adjusted hazard ratio AHR, 2.09; 95% confidence interval CI, 1.2-3.64; P=.005) and long-term MACEs (AHR, 1.99; 95% CI, 1.18-3.38; P<.01).
DES implantation during PCI for single CTO reduces MACE rate at 1-year and long-term follow-up due to the significant reduction of TLR in the DES group. Therefore, DES implantation should be preferred as an optimal treatment strategy of single CTO in stable angina patients.
The long-term benefit of percutaneous recanalisation of chronic total occlusion (CTO) is still unclear. Given advances in interventional cardiology over the last two decades, we sought to investigate ...whether a successful percutaneous coronary intervention for CTO (PCI-CTO) improves outcomes in an age- and gender-matched single-centre cohort of stable angina patients.
Out of 401 consecutive patients enrolled to the CTO-Registry database, 276 patients were included in the final analysis. Patients with unsuccessful PCI-CTO (n = 138) were age- and gender-matched in a 1:1 ratio with patients who underwent a successful procedure. The primary end-points included hard end-points comprising death and nonfatal myocardial infarction (MI) and a composite safety outcome measure of death, nonfatal MI and ischaemia-driven revascularisation. The secondary end-point was improvement in angina status or complete resolution of angina symptoms. Patients were followed up for six months and at two years.
Patients who underwent a successful recanalisation of CTO, compared to those who underwent an unsuccessful procedure, revealed similar rates of composite death and MI at six months (0.7% vs. 1.4%; hazard ratio HR, 0.50; 95% confidence interval ratio CI, 0.05-4.80; p = 0.56) and two years (1.4% vs. 5.8%; HR 0.24; 95% CI 0.07-0.85; p = 0.053). A significant difference in composite safety end-points between subsets, although not recorded after six months of observation (8.7% vs. 15.2%; HR 0.54; 95% CI 0.27-1.07; p = 0.095), was noted at two years follow-up (15.2% vs. 29.7%; HR 0.47; 95% CI 0.29-0.77; p = 0.004). A greater improvement in symptom burden or resolution of angina symptoms was documented after a successful PCI at both six months (68.1% vs. 23.2%, p < 0.001; 80.4% vs. 34.8%, p < 0.001, respectively) and two years (52.2% and 8.0%, p < 0.001; 68.1% vs. 22.5%, p < 0.001, respectively).
Successful recanalisation of CTO improves outcomes in long-term observation.
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