Effect of Steel Fibers on Precast Dapped-end Beam Connections

The analysis of connections in precast concrete structures is complex due to the concentration of stresses on the bearing areas that transfer loads from one member to another. The design equations available were developed through field experience, tests and structural analysis. Proper design should take into consideration the safety, simplicity, and economical and practical applications of these connections, as well as the production of structural units and construction situations pertinent to precast concrete buildings. Proper reinforcement must be provided to ensure the safety of the connection. One possible improvement is the addition of steel fibers to the concrete mix. The presence of steel fibers is expected to reduce cracking and increase the shear load capacity of the connection. In this research, different ratios of steel fibers to concrete will be used. Also, different patterns of shear reinforcement will be adopted. The depth ratio of the recessed ends to the total depth of the main beams will also be varied to investigate the contribution of steel fibers in shallower end depths. A total of 18 dapped-end beams will be prepared and tested up to failure. In general, the main objective of this research program is to study the dapped-end connection with respect to the following: 1) to simplify the reinforcement details of the connection as shown in Figure 1.3. 2) To determine the different modes of failure. 3) To investigate the contribution of steel fibers to the strength capacity of the connection. 4) To investigate the possibility of replacing part of the reinforcement with steel fibers. 5) To study the effect of the variation in the ratio of the dapped-end depth to the total depth on the strength capacity of the connection. 6) To develop new expressions to evaluate the strength of the connection when steel fibers are used. 7) To determine such physical properties of fibrous concrete as the compressive strength, the modulus of elasticity, flexural strength, and split tensile strength

Mechanistic Studies of the Effect of Nitrogen-Based Detergents on Gum Adsorption from Gasoline Fuels

Deposition of carbonaceous materials on internal surfaces of spark ignition engines is a long-standing problem that can seriously impact engine performance. For gasoline fuel, deposit control additives (‘detergents’) comprising nitrogen-based detergents are commonly used to inhibit deposition and minimise its effects. However, the molecular basis of their detergency is still poorly understood. The most commonly quoted mechanistic hypothesis assumes that gasoline detergents inhibit deposit formation via surface passivation. i.e. by forming an adsorbed 2D thin film phase that protects the metal surface. The present work constitutes a first step towards establishing a systematic protocol for analysing the molecular mechanisms leading to the macroscopically observable detergency effect. This was done by synthesising a model fuel system that contained carbonaceous material (‘gum’) that can deposit on steel surfaces. First, a method for the synthesis of gum by a radical oxidation of mono- and diolefin components with air was developed. This established a reproducible method for oxidising gasoline surrogate to create gum. FTIR spectroscopy along with other analytical characterisation techniques were employed to validate the formulation and oxidation methods, the resulting oxidation product, and their deposits on steel surfaces. Then, the influence of a model detergent, 1-octadecylamine (ODA), on the oxidised fuel was studied. In solution, it interacts strongly with polar groups of the gum, likely solubilising it and thereby shifting any interfacial adsorption equilibrium towards the solution state. Gum deposition and detergency were then examined by using 316 stainless steel substrates. The ODA concentration was found to not only influence the adsorption equilibrium, but also the morphology of deposits on the surfaces, minimising the surface area covered by them. A systematic experimental design was developed to investigate the solid-liquid interactions at the stainless steel/solution interface in more detail. X-ray photoelectron spectroscopy was extensively used as the main surface sensitive technique to gain insight into the molecular basis of adsorption and detergency in this system. The results revealed that the detergency process was related mainly to solubilisation of gum in the solution phase, rather than surface passivation by formation of an adsorbed ODA layer. Adsorbed ODA was only evident when unrealistically high ODA concentrations were used

Age-related changes in global motion coherence: conflicting haemodynamic and perceptual responses

Our aim was to use both behavioural and neuroimaging data to identify indicators of perceptual decline in motion processing. We employed a global motion coherence task and functional Near Infrared Spectroscopy (fNIRS). Healthy adults (n = 72, 18-85) were recruited into the following groups: young (n = 28, mean age = 28), middle-aged (n = 22, mean age = 50), and older adults (n = 23, mean age = 70). Participants were assessed on their motion coherence thresholds at 3 different speeds using a psychophysical design. As expected, we report age group differences in motion processing as demonstrated by higher motion coherence thresholds in older adults. Crucially, we add correlational data showing that global motion perception declines linearly as a function of age. The associated fNIRS recordings provide a clear physiological correlate of global motion perception. The crux of this study lies in the robust linear correlation between age and haemodynamic response for both measures of oxygenation. We hypothesise that there is an increase in neural recruitment, necessitating an increase in metabolic need and blood flow, which presents as a higher oxygenated haemoglobin response. We report age-related changes in motion perception with poorer behavioural performance (high motion coherence thresholds) associated with an increased haemodynamic response

Zn treatment effects on biological potential of fennel bulbs as affected by in vitro digestion process

Zn treatment effects on the stability of polyphenols, MDA (malondialdehyde) content, antioxidant and lipoxygenase inhibition activities of two varieties of fennel bulbs were studied by using an in vitro gastrointestinal digestion model. Likewise, the effect of Zn on viability cells of E. coli was also performed. The results revealed that high amounts of total phenolic and flavonoid compounds were released during the digestion process, especially after the intestinal phase. Additionally, the antioxidant and lipoxygenase inhibitory activity were affected by the gastrointestinal digestion process and seems to be correlated with total phenol contents. On the other hand, the viability of E. coli was not affected by the activity of our tested bulbs during passage through the artificial digestion model, but the treated bulbs activity contribute relatively to the inhibition growth of bacteria. The survival of E. coli in fennel bulbs was challenged with simulated gastrointestinal fluids and the results showed that the E. coli strains, despite having experienced a viability reduction at the intestinal phase, were able to overcome the exposure to the gastrointestinal synthetic fluids. This E. coli ability reinforces the need for good hygienic measures to assure safe fresh produce, even for those that are rich in antibacterial compounds.info:eu-repo/semantics/publishedVersio

Repurposing the oncolytic virus VSV∆51M as a COVID-19 vaccine

The coronavirus disease 2019 (COVID-19) pandemic imposes an urgent and continued need for the development of safe and cost-effective vaccines to induce preventive responses for limiting major outbreaks around the world. To combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we repurposed the VSV∆51M oncolytic virus platform to express the spike receptor-binding domain (RBD) antigen. In this study, we report the development and characterization of the VSV∆51M-RBD vaccine. Our findings demonstrate successful expression of the RBD gene by the VSV∆51M-RBD virus, inducing anti-RBD responses without attenuating the virus. Moreover, the VSV∆51M-RBD vaccine exhibited safety, immunogenicity, and the potential to serve as a safe and effective alternative or complementary platform to current COVID-19 vaccines

Impact of seminal trace element and glutathione levels on semen quality of Tunisian infertile men

<p>Abstract</p> <p>Background</p> <p>Growing evidence indicates that oxidative stress can be a primary cause of male infertility. Non-enzymatic antioxidants play an important protective role against oxidative damages and lipid peroxidation. Human seminal plasma is a natural reservoir of antioxidants. The aim of this study was to determine glutathione (GSH) concentrations, trace element levels (zinc and selenium) and the lipid peroxidation end product, malondialdehyde (MDA), in the seminal plasma of men with different fertility potentials.</p> <p>Methods</p> <p>Semen samples from 60 fertile men (normozoospermics) and 190 infertile patients (74 asthenozoospermics, 56 oligozoospermics, and 60 teratozoospermics) were analyzed for physical and biochemical parameters. Zinc (Zn) and selenium (Se) levels were estimated by atomic absorption spectrophotometry. Total GSH (GSHt), oxidized GSH (GSSG), reduced GSH (GSHr) and MDA concentrations were measured spectrophotometrically.</p> <p>Results</p> <p>Zn and Se concentrations in seminal plasma of normozoospermics were more elevated than the three abnormal groups. Nevertheless, only the Zn showed significant differences. On the other hand, Zn showed positive and significant correlations with sperm motility (P = 0.03, r = 0.29) and count (P < 0.01, r = 0.49); however Se was significantly correlated only with sperm motility (P < 0.01, r = 0.36). GSHt, GSSG and GSHr were significantly higher in normozoospermics than in abnormal groups. We noted a significant association between seminal GSHt and sperm motility (P = 0.03). GSSG was highly correlated to sperm motility (P < 0.001) and negatively associated to abnormal morphology (P < 0.001). GSHr was significantly associated to total sperm motility (P < 0.001) and sperm count (P = 0.01). MDA levels were significantly higher in the three abnormal groups than in normozoospermics. Rates of seminal MDA were negatively associated to sperm motility (P < 0.01; r = -0.24) and sperm concentration (P = 0.003; r = -0.35) Meanwhile, there is a positive correlation between seminal lipid peroxidation and the percentage of abnormal morphology (P = 0.008).</p> <p>Conclusions</p> <p>This report revealed that decreased seminal GSH and trace element deficiencies are implicated in low sperm quality and may be an important indirect biomarker of idiopathic male infertility. Our results sustain that the evaluation of seminal antioxidant status in infertile men is necessary and can be helpful in fertility assessment from early stages.</p

Male Oxidative Stress Infertility (MOSI): Proposed Terminology and Clinical Practice Guidelines for Management of Idiopathic Male Infertility

Despite advances in the field of male reproductive health, idiopathic male infertility, in which a man has altered semen characteristics without an identifiable cause and there is no female factor infertility, remains a challenging condition to diagnose and manage. Increasing evidence suggests that oxidative stress (OS) plays an independent role in the etiology of male infertility, with 30% to 80% of infertile men having elevated seminal reactive oxygen species levels. OS can negatively affect fertility via a number of pathways, including interference with capacitation and possible damage to sperm membrane and DNA, which may impair the sperm’s potential to fertilize an egg and develop into a healthy embryo. Adequate evaluation of male reproductive potential should therefore include an assessment of sperm OS. We propose the term Male Oxidative Stress Infertility, or MOSI, as a novel descriptor for infertile men with abnormal semen characteristics and OS, including many patients who were previously classified as having idiopathic male infertility. Oxidation-reduction potential (ORP) can be a useful clinical biomarker for the classification of MOSI, as it takes into account the levels of both oxidants and reductants (antioxidants). Current treatment protocols for OS, including the use of antioxidants, are not evidence-based and have the potential for complications and increased healthcare-related expenditures. Utilizing an easy, reproducible, and cost-effective test to measure ORP may provide a more targeted, reliable approach for administering antioxidant therapy while minimizing the risk of antioxidant overdose. With the increasing awareness and understanding of MOSI as a distinct male infertility diagnosis, future research endeavors can facilitate the development of evidence-based treatments that target its underlying cause

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

The Effect of Glide Path Preparation on Root Canal Shaping Procedures and Outcomes.

The 'glide path' in non-surgical root canal treatment refers to a smooth radicular tunnel from the root canal orifice to its terminus. Its establishment is aimed at creating sufficient space to facilitate the subsequent and safer use of engine-driven nickel titanium (NiTi) shaping files. Glide paths were originally prepared using stainless steel hand files to, at least, a loose International Organisation for Standardisation (ISO) size 10 or larger. However, the advent of engine-driven NiTi instrumentation has led to the availability of many engine-driven NiTi glide path files. The aims of this review were to assess the effects of engine-driven and manual glide path preparation (GPP) on root canal shaping procedures and outcomes. An online search of the PubMed, Embase, Scopus and ScienceDirect databases was conducted and 32 studies were identified. The published literature suggests the use of engine-driven glide path files to be beneficial in maintaining the original root canal anatomy, reducing preparation time, decreasing apical extrusion of debris and causing less postoperative pain. However, there was no difference between engine-driven and manual GPP with regards to the physical strain exerted on the shaping files. Future research focused on clinical outcomes is needed to help ascertain the clinical benefits for patients