189 research outputs found

    Seropositivity to non-vaccine incorporated genotypes induced by the bivalent and quadrivalent HPV vaccines: A systematic review and meta-analysis.

    Get PDF
    BACKGROUND: Human papillomavirus vaccines have demonstrated remarkable efficacy against persistent infection and disease associated with vaccine-incorporated genotypes and a degree of efficacy against some genetically related, non-vaccine-incorporated genotypes. The vaccines differ in the extent of cross-protection against these non-vaccine genotypes. Data supporting the role for neutralizing antibodies as a correlate or surrogate of cross-protection are lacking, as is a robust assessment of the seroconversion rates against these non-vaccine genotypes. METHODS: We performed a systematic review and meta-analysis of available data on vaccine-induced neutralizing antibody seropositivity to non-vaccine incorporated HPV genotypes. RESULTS: Of 304 articles screened, 9 were included in the analysis representing ca. 700 individuals. The pooled estimate for seropositivity against HPV31 for the bivalent vaccine (86%; 95%CI 78-91%) was higher than that for the quadrivalent vaccine (61%; 39-79%; p=0.011). The pooled estimate for seropositivity against HPV45 for the bivalent vaccine (50%; 37-64%) was also higher than that for the quadrivalent vaccine (16%; 6-36%; p=0.007). Seropositivity against HPV33, HPV52 and HPV58 were similar between the vaccines. Mean seropositivity rates across non-vaccine genotypes were positively associated with the corresponding vaccine efficacy data reported from vaccine trials. CONCLUSIONS: These data improve our understanding of vaccine-induced functional antibody specificity against non-vaccine incorporated genotypes and may help to parameterize vaccine-impact models and improve patient management in a post-vaccine setting

    Transition from single to multi-walled carbon nanotubes grown by inductively coupled plasma enhanced chemical vapor deposition

    Get PDF
    In this work a simple and up-scalable technique for creating arrays of high purity carbon nanotubes via plasma enhanced chemical vapor deposition is demonstrated. Inductively coupled plasma enhanced chemical vapor deposition was used with methane and argon mixtures to grow arrays in a repeatable and controllable way. Changing the growth conditions such as temperature and growth time led to a transition between single and multi-walled carbon nanotubes and was investigated. This transition from single to multi-walled carbon nanotubes is attributed to a decrease in catalytic activity with time due to amorphous carbon deposition combined with a higher susceptibility of single-walled nanotubes to plasma etching. Patterning of these arrays was achieved by physical masking during the iron catalyst deposition process. The low growth pressure of 100 mTorr and lack of reducing gas such as ammonia or hydrogen or alumina supporting layer further show this to be a simple yet versatile procedure. These arrays were then characterized using scanning electron microscopy, Raman spectroscopy and x-ray photoelectron spectroscopy. It was also observed that at high temperature (550 °C) single-walled nanotube growth was preferential while lower temperatures (450 °C) produced mainly multi-walled arrays

    Anodic dissolution growth of metal-organic framework HKUST-1 monitored:Via in situ electrochemical atomic force microscopy

    Get PDF
    In situ electrochemical atomic force microscopy (ec-AFM) is utilised for the first time to probe the initial stages of metal-organic framework (MOF) coating growth via anodic dissolution. Using the example of the Cu MOF HKUST-1, real time surface analysis is obtained that supports and verifies many of the reaction steps in a previously proposed mechanism for this type of coating growth. No evidence is observed however for the presence or formation of Cu2O, which has previously been suggested to be both key for the formation of the coating and a potential explanation for the anomalously high adhesion strength of coatings obtained via this methodology. Supporting in situ electrochemical Raman spectroscopy also fails to detect the presence of any significant amount of Cu2O before or during the coating's growth process

    Fabrication and Mechanical Performance of Graphene Nanoplatelet/Glass Fiber Reinforced Polymer Hybrid Composites

    Get PDF
    From Frontiers via Jisc Publications RouterHistory: collection 2021, received 2021-09-09, accepted 2021-10-20, epub 2021-11-16Publication status: PublishedGlass fiber reinforced polymer (GFRP) composites are promising alternatives for the traditional carbon steel pipes used in the oil and gas industry due to their corrosion and chemical resistance. However, the out-of-plane mechanical properties of GFRPs still need further improvement to achieve this goal. Hence, in this work, two methods combining either vacuum mixing or spray coating with vacuum-assisted resin infusion were studied to fabricate graphene nanoplatelet (GNP)/GFRP hybrid composites. The former method resulted in a severe filtering effect, where the GNPs were not evenly distributed throughout the final composite, whereas the latter process resulted in a uniform GNP distribution on the glass fabrics. The addition of GNPs showed no modest contribution to the tensile performance of the GFRP composites due to the relatively high volume and in-plane alignment of the glass fibers. However, the GNPs did improve the flexural properties of GFRP with an optimal loading of 0.15 wt% GNPs, resulting in flexural strength and modulus increases of 6.8 and 1.6%, respectively. This work indicates how GNPs can be advantageous for out-of-plane mechanical reinforcement in fiber-reinforced composites

    Electrically Conductive 2D Material Coatings for Flexible & Stretchable Electronics: A Comparative Review of Graphenes & MXenes

    Full text link
    There is growing interest in transitioning electronic components and circuitry from stiff and rigid substrates to more flexible and stretchable platforms, such as thin plastics, textiles, and foams. In parallel, the push for more sustainable, biocompatible, and cost-efficient conductive inks to coat these substrates, has led to the development of formulations with novel nanomaterials. Among these, 2D materials, and particularly graphenes and MXenes, have received intense research interest due to their increasingly facile and scalable production, high electrical conductivity, and compatibility with existing manufacturing techniques. They enable a range of electronic devices, including strain and pressure sensors, supercapacitors, thermoelectric generators, and heaters. These new flexible and stretchable electronic devices developed with 2D material coatings are poised to unlock exciting applications in the wearable, healthcare and Internet of Things sectors. This review has surveyed key data from more than 200 articles published over the last 6 years, to provide a quantitative analysis of recent progress in the field and shade light on future directions and prospects of this technology. We find that despite the different chemical origins of graphenes and MXenes, their shared electrical properties and 2D morphology, guarantee intriguing performance in end applications, leaving plenty of space for shared progress and advancements in the future

    Electrical Erosion Resistance of Graphene Reinforced Cu-W Circuit Breaker Contact Materials under 5 kA Arc

    Get PDF
    This work integrates experimental and MD simulation approaches to study the role of graphene in G-Cu-W composites. Arcing tests were conducted on G-Cu-W and Cu-W contact samples under a 5kA peak current. Experimental results show that adding graphene leads to a lower surface roughness of the sample following arcing. MD simulation results indicate that the G-Cu-W model exhibits a smoother surface and fewer lost metal atoms than the Cu-W model due to the protective effect of graphene layer

    The Modified Liquid‐Liquid Interface: The Effect of an Interfacial Layer of MoS 2 on Ion Transfer

    Get PDF
    From Wiley via Jisc Publications RouterHistory: received 2021-06-15, rev-recd 2021-08-08, pub-electronic 2021-10-28Article version: VoRPublication status: PublishedFunder: Ministry of Education, Saudi ArabiaFunder: EPSRC; Id: http://dx.doi.org/10.13039/501100000266; Grant(s): EP/R023034/1Abstract: MoS2 nanosheets have been assembled at the water|1,2‐dichlorobenzene (DCB) interface into uniform films, and the ion‐transfer properties investigated by voltammetry at the interface between immiscible electrolyte solutions. Remarkably, interfacial MoS2 films were found to enhance the simple and facilitated transfer of cationic species while restricting the transport of anionic species. The enhancement is attributed to a localised increase in the cationic concentration at the interface due to the adsorption onto the negatively charged surface of the exfoliated MoS2 nanosheets. Size‐selectivity for the cationic species was also recognized as a feature of such films. Characterisation of the interfacial film's structure revealed the inclusion of multiple emulsified droplets stabilised by MoS2, where the droplet number and size depend on the concentration of the MoS2 dispersion. Besides increasing the interfacial corrugation and area, the emulsified droplets are believed to influence the mass transport mechanism across the interface. Cyclic voltammetric measurements of saturated films suggested a capillary‐like structure of these films. While the capillaries/nanochannels allow them to have a degree of size‐selectivity that depends on the thickness/density of the film, they also affect the diffusion zones towards and away from the interface. Consequently, steady‐state conditions of mass transport similar to those found in solid‐state supported micro‐ITIES are observed in these nanofilms
    • 

    corecore