Response of Novel Functionally-Graded Prepacked Aggregate Fibrous Concrete against Low Velocity Repeated Projectile Impacts

Preplaced Aggregate Fibrous Concrete (PAFC) is a newly minted composite that has recently become more popular. The production of PAFC involves two essential processes; first, the fibres and coarse aggregate were filled into the empty framework to form the first layer of a natural skeleton, followed by grout injecting. A cement grout fills the voids in the first layer skeleton with slight compaction. This process is repeated to complete the remaining layers; hence, a type of Functionally-graded Preplaced Aggregate Fibrous Concrete (FPAFC) is obtained. The most recent studies revealed that the literature regarding the high-velocity projectile impact on fibrous concrete is well documented; however, the low-velocity repeated projectile impact on PAFC is still unexplored and needs particular emphasis. This research aims to investigate the FPAFC made with a new type of steel and polypropylene fibres against low-velocity projectile impact to fill this research gap. In the current study, twelve mixes were prepared with mono and hybrid combinations of fibres for pioneering the possible utilization of fibres in FPAFC. The maximum fibre dosage in this study is limited to 2.4%. The projectile impact resistance of FPAFC was assessed in line with penetration depth, front and rear damage surface area, weight loss, damage ratio and failure pattern. Additionally, a simplified analytical model was introduced to compute the ejected composite mass from the tested specimens. The results revealed that the addition of steel fibre in a single layer FPAFC exhibited an increasing compressive strength trend compared to the two/three-layered FPAFC. Furthermore, increasing the dosage of fibre at the bottom and top layers of FPAFC with a hybrid combination alleviates the spalling with an increasing number of impacts. The results from this research offer the reference information for more detailed research and studies of FPAFC under low-velocity projectile impact.     

Motility initiation in herring sperm is regulated by reverse sodium-calcium exchange

Sperm of the Pacific herring, Clupea pallasi, are unique in that they are immotile upon spawning in the environment. Herring sperm have evolved to remain motionless for up to several days after spawning, yet are still capable of fertilizing eggs. An egg chorion ligand termed "sperm motility initiation factor" (SMIF) induces motility in herring sperm and is required for fertilization. In this study, we show that SMIF induces calcium influx, sodium efflux, and a membrane depolarization in herring sperm. Sperm motility initiation by SMIF depended on decreased extracellular sodium (<350 mM) and could be induced in the absence of SMIF in very low sodium seawater. Motility initiation depended on > or =1 mM extracellular calcium. Calcium influx caused by SMIF involved both the opening of voltage-gated calcium channels and reverse sodium-calcium (Na(+)/Ca(2+)) exchange. Membrane depolarization was slightly inhibited by a calcium channel blocker and markedly inhibited by a Na(+)/Ca(2+) exchange inhibitor. Sodium efflux caused by SMIF-initiated motility was observed when using both extracellular and intracellular sodium probes. A Na(+)/Ca(2+) exchange antigen was shown to be present on the surface of the sperm, primarily over the midpiece, by using an antibody to the canine Na(+)/Ca(2+) exchanger. This antibody recognized a 120-kDa protein that comigrated with the canine myocyte Na(+)/Ca(2+) exchanger. Sperm of Pacific herring are now shown to use reverse Na(+)/Ca(2+) exchange in motility initiation. This mechanism of regulation of motility initiation may have evolved for both maintenance of immotility after spawning as well as ligand-induced motility initiation.     

Utility of impedance cardiography for the identification of short-term risk of clinical decompensation in stable patients with chronic heart failure.

OBJECTIVES: This study sought to assess the potential utility of impedance cardiography (ICG) in predicting clinical deterioration in ambulatory patients with heart failure (HF). BACKGROUND: Impedance cardiography uses changes in thoracic electrical impedance to estimate hemodynamic variables, but its ability to predict clinical events has not been evaluated. METHODS: We prospectively evaluated 212 stable patients with HF and a recent episode of clinical decompensation who underwent serial clinical evaluation and blinded ICG testing every 2 weeks for 26 weeks and were followed up for the occurrence of death or worsening HF requiring hospitalization or emergent care. RESULTS: During the study, 59 patients experienced 104 episodes of decompensated HF (16 deaths, 78 hospitalizations, and 10 emergency visits). Multivariate analysis identified 6 clinical and ICG variables that independently predicted an event within 14 days of assessment. These included three clinical variables (visual analog score, New York Heart Association functional class, and systolic blood pressure) and three ICG parameters (velocity index, thoracic fluid content index, and left ventricular ejection time). The three ICG parameters combined into a composite score was a powerful predictor of an event during the next 14 days (p = 0.0002). Visits with a high-risk composite score had 2.5 times greater likelihood and those with a low-risk score had a 70% lower likelihood of a near-term event compared with visits at intermediate risk. CONCLUSIONS: These results suggest that when performed at regular intervals in stable patients with HF with a recent episode of clinical decompensation, ICG can identify patients at increased near-term risk of recurrent decompensation.     

Molecular Evolution of Peste des Petits Ruminants Virus

Despite safe and efficacious vaccines against peste des petits ruminants virus (PPRV), this virus has emerged as the cause of a highly contagious disease with serious economic consequences for small ruminant agriculture across Asia, the Middle East, and Africa. We used complete and partial genome sequences of all 4 lineages of the virus to investigate evolutionary and epidemiologic dynamics of PPRV. A Bayesian phylogenetic analysis of all PPRV lineages mapped the time to most recent common ancestor and initial divergence of PPRV to a lineage III isolate at the beginning of 20th century. A phylogeographic approach estimated the probability for root location of an ancestral PPRV and individual lineages as being Nigeria for PPRV, Senegal for lineage I, Nigeria/Ghana for lineage II, Sudan for lineage III, and India for lineage IV. Substitution rates are critical parameters for understanding virus evolution because restrictions in genetic variation can lead to lower adaptability and pathogenicity.     

Pharmacogenetic interactions between angiotensin-converting enzyme inhibitor therapy and the angiotensin-converting enzyme deletion polymorphism in patients with congestive heart failure

OBJECTIVES: We evaluated the interaction of angiotensin-converting enzyme (ACE) inhibitor therapy with the effect of the ACE D/I polymorphism on heart failure survival. BACKGROUND: The ACE deletion allele, ACE-D, is associated with increased ACE activity. The utilization of ACE genotyping to predict the impact of ACE inhibitor dose has not been previously evaluated. METHODS: We prospectively studied 479 subjects with systolic dysfunction (left ventricular ejection fraction 0.25 +/- 0.08). Subjects were divided on the basis of ACE inhibitor therapy into low dose (50%, n = 201), or those receiving angiotensin receptor antagonists (n = 51). Patients were genotyped for the ACE D/I polymorphism, followed to the end point of death or cardiac transplantation, and transplant-free survival compared by genotype. RESULTS: The ACE-D allele was associated with an increased risk of events (p = 0.026). In analysis by ACE inhibitor dose, this effect was primarily in the low-dose group (1-year percent event-free survival: II/ID/DD = 86/77/71,2-year = 79/66/59, p = 0.032). In the standard-dose group, the impact was markedly diminished (1-year: II/ID/DD = 91/81/80, 2-year: 77/70/71, p = 0.64). The impact of beta-blockers and high dose ACE inhibitors was greatest in subjects with the ACE DD genotype (p = 0.001) and was less apparent with the II and ID genotypes (p = 0.38). CONCLUSIONS: Higher doses of ACE inhibitors diminished the impact of the ACE-D allele, and the benefits of beta-blockers and high-dose ACE inhibitors appeared maximal for DD patients. Determination of ACE genotype may help target therapy for patients with heart failure.     

Acute systemic immune activation following vaginal exposure to staphylococcal enterotoxin B--implications for menstrual shock

Menstrual toxic shock syndrome (mTSS) is an acute systemic inflammatory disease associated with the superantigenic exotoxin, toxic shock syndrome toxin (TSST)-1, produced by Staphylococcus aureus and the use of high absorbency tampons. Even though S. aureus is capable of elaborating several other superantigenic exotoxins, only TSST-1 has been implicated in the pathogenesis of mTSS possibly because most other superantigenic exotoxins are known enterotoxins. Nonetheless, we have shown recently that one of the enterotoxigenic staphylococcal superantigens, staphylococcal enterotoxin B (SEB), can cause robust systemic immune activation following exposure through non-enteric mucosa, including nasal or conjunctival routes. In a similar manner, we show here that vaginal administration of SEB in HLA class II transgenic mice can cause robust systemic immune activation characterized by profound elevation of proinflammatory cytokines in the serum, activation and expansion of SEB-reactive CD4(+) and CD8(+) T cells in peripheral lymphoid organs and SEB-induced deletion of immature thymocytes. Vaginal administration of SEB also caused leukocytic infiltration in major organs, such as liver and lung, reminiscent of human toxic shock syndrome. Systemic immune activation following vaginal superantigen delivery was independent of the stage of the estrus cycle in the mouse. Using HLA class II transgenic mice, we have shown that exposure to SEB through the vaginal canal can cause robust systemic immune activation. SEB could thus play a role in the pathogenesis of mTSS.     

Experimental Investigations on Dry Sliding Wear Behavior of Kevlar and Natural Fiber-Reinforced Hybrid Composites through an RSM–GRA Hybrid Approach

The present work aimed to investigate the dry sliding wear behaviors of hybrid polymer matrix composites made up of Kevlar, bamboo, palm, and Aloe vera as reinforcement materials of varying stacking sequences, along with epoxy as the matrix material. Three combinations of composite laminates with different stacking sequences such as AB, BC, and CA were fabricated by a vacuum-assisted compression molding process. The influence of composite laminates fabricated through various stacking sequences and dry sliding wear test variables such as load, sliding distance, and sliding velocity on the specific wear rate and co-efficient of friction were investigated. Experiments were designed and statistical validation was performed through response surface methodology-based D-optimal design and analysis of variance. The optimization was performed using grey relational analysis (GRA) to identify the optimal parameters to enhance the wear resistance of hybrid polymer composites under dry sliding conditions. The optimal parameters, such as composite combinations of CA, a load of 5 N, a sliding velocity of 3 m/s, and a sliding distance of 1500 m, were obtained. Furthermore, the morphologies of worn-out surfaces were investigated using SEM analysis.