190 research outputs found
Bacteria have transient influences on marine corrosion of steel
The contribution of bacteria to the corrosion mass loss and to pitting of mild steel was observed over 2.5 years using parallel streams of unpolluted natural (biotic) and nominally sterilized (abiotic) Pacific Ocean coastal seawater. As also observed by others, in artificial laboratory exposures, corrosion mass loss within the first few days of exposure was much greater in the biotic stream. However, after only about 10 days the difference in mass losses were gradually reduced and were very similar up to about one year of exposure. Thereafter, the corrosion loss in the biotic stream again became more severe. Pitting corrosion in the biotic stream was more severe from the very first exposure throughout the 2.5 years. Corrosion in both seawater streams exhibited three distinct but transient time-dependent phases. Of these only the first and third obviously involve bacteria. Similar longer-term observations in real seawaters have not been described previously but are generally consistent with some long-term field data. The results show that longer-term corrosion behavior and possible microbial influences cannot be predicted from short-term laboratory observations, even if natural seawater is used
Field experience and the long-term durability of reinforced concrete structures
For reinforced concrete structures the conventional wisdom is that after some years of exposure to marine conditions reinforcement corrosion is inevitable. Much attention is paid in the literature to the rate of ingress of chlorides through the concrete cover to the reinforcing bars and to ensuring highly impermeable cover and/or deeper cover, to try top prevent chloride-induced or carbonation-induced corrosion initiation. Actual field experience shows that there are many reinforced concrete structures that have survived remarkably well for many decades despite having very high chloride concentrations next to the reinforcing bars. Even with very modest concrete cover by modern standards, exhumation often finds bars free from corrosion. Detailed investigations of a number of such cases showed no corrosion if the concrete pH levels are above about 9. On the other hand, very severe reinforcement corrosion was observed in the few cases where the concrete had cracked right through the cover to the bars. Often there was no external evidence or signs of interior corrosion, including longitudinal cracking. The implications of these findings for practice are discussed
Onchocerciasis-associated epilepsy in Maridi, South Sudan:Modelling and exploring the impact of control measures against river blindness
A stabilized HIV-1 envelope glycoprotein trimer fused to CD40 ligand targets and activates dendritic cells
<p>Abstract</p> <p>Background</p> <p>One reason why subunit protein and DNA vaccines are often less immunogenic than live-attenuated and whole-inactivated virus vaccines is that they lack the co-stimulatory signals provided by various components of the more complex vaccines. The HIV-1 envelope glycoprotein complex (Env) is no exception to this rule. Other factors that limit the induction of neutralizing antibodies against HIV-1 lie in the structure and instability of Env. We have previously stabilized soluble trimeric mimics of Env by introducing a disulfide bond between gp120 and gp41 and adding a trimer stabilizing mutation in gp41 (SOSIP.R6 gp140).</p> <p>Results</p> <p>We further stabilized the SOSIP.R6 gp140 using a GCN4-based isoleucine zipper motif, creating SOSIP.R6-IZ gp140. In order to target SOSIP.R6-IZ to immune cells, including dendritic cells, while at the same time activating these cells, we fused SOSIP.R6-IZ to the active domain of CD40 ligand (CD40L), which may serve as a '<it>cis</it>-adjuvant'. The Env component of the SOSIP.R6-IZ-CD40L fusion construct bound to CD4 and neutralizing antibodies, while the CD40L moiety interacted with CD40. Furthermore, the chimeric molecule was able to signal efficiently through CD40 and induce maturation of human dendritic cells. Dendritic cells secreted IL-6, IL-10 and IL-12 in response to stimulation by SOSIP.R6-IZ-CD40L and were able to activate naïve T cells.</p> <p>Conclusions</p> <p>Chimeric HIV-1 gp140 - CD40L trimers can target and activate dendritic cells. Targeting and activating immune cells using CD40L and other '<it>cis</it>-adjuvants' may improve subunit protein vaccine immunogenicity for HIV-1 and other infectious diseases.</p
FGFR Family Members Protein Expression as Prognostic Markers in Oral Cavity and Oropharyngeal Squamous Cell Carcinoma
Introduction Fibroblast growth factor receptor family member proteins (FGFR1-4) have been identified as promising novel therapeutic targets and prognostic markers in a wide spectrum of solid tumors. The present study investigates the expression and prognostic value of four FGFR family member proteins in a large multicenter oral cavity squamous cell carcinoma (OCSCC) and oropharyngeal squamous cell carcinoma (OPSCC) cohort. Methods Protein expression of FGFR1-4 was determined by immunohistochemistry on tissue microarrays containing 951 formalin-fixed paraffin embedded OCSCC and OPSCC tissues from the University Medical Center Utrecht and University Medical Center Groningen. Protein expression was correlated to overall survival using Cox regression models, and bootstrapping was performed as internal validation. Results FGFR proteins were highly expressed in 39-64 % of OCSCC and 63-79 % of OPSCC. Seventy-three percent (299/412) of OCSCC and 85 % (305/357) of OPSCC highly co-expressed two or more FGFR family member proteins. FGFR1 protein was more frequently highly expressed in human papillomavirus (HPV)-negative OPSCC than HPV-positive OPSCC (82 vs. 65 %; p = 0.008). Furthermore, protein expression of FGFR family members was not related to overall survival in OCSCC or OPSCC (p . 0.05). Conclusion FGFR family members are frequently highly expressed in OCSCC and OPSCC. These FGFR family member proteins are therefore potential targets for novel therapies that are urgently required to improve survival of OCSCC and OPSCC patients
Emericella quadrilineata as Cause of Invasive Aspergillosis
This opportunistic fungus is frequently misidentified because of its morphologic similarity to E. nidulans
Emergence of Azole Resistance in Aspergillus fumigatus and Spread of a Single Resistance Mechanism
Paul Verweij and colleagues show that azole resistance has emerged inAspergillus fumigatus in The Netherlands and that a dominant resistance mechanism is present in clinical isolates
Burden of onchocerciasis-associated epilepsy: First estimates and research priorities
__Background:__ Since the 1990s, evidence has accumulated of an increased prevalence of epilepsy in onchocerciasis-endemic areas in Africa as compared to onchocerciasis-free areas. Although the causal relationship between onchocerciasis and epilepsy has yet to be proven, there is likely an association.
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