Freezing and Thawing Resistance of Fine Recycled Concrete Aggregate (FRCA) Mixtures Designed with Distinct Techniques

The pressure to use sustainable materials and adopt practices reducing the carbon footprint of the construction industry has risen. Such materials include recycled concrete aggregates (RCA) made from waste concrete. However, concrete made with RCA often presents poor fresh and hardened properties along with a decrease in its durability performance, especially when using its fine fraction (i.e., FRCA). Most studies involving FRCA use direct replacement methods (DRM) to proportion concrete although other techniques are available such as the Equivalent Volume (EV) and Particle Packing Models (PPMs); yet their impact on the durability performance, especially its performance against freezing and thawing (F/T), remains unknown. This work, therefore, appraises the F/T resistance of FRCA mixtures proportioned through various mix proportioning techniques (i.e., DRM, EV and PPMs), produced with distinct crushing processes (i.e., crusher’s fines vs. finely ground). The results show that the mix design technique has a significant influence on the FRCA mixture’s F/T resistance where PPM-proportioned mixtures demonstrate the best overall performance, exceeding the specified requirements while DRM-proportioned mixtures failed F/T resistance requirements. Moreover, the crushing process plays an important role in the recycled mixtures’ cracking behavior under F/T cycles, where less processing leads to fewer cracks while remaining the most sustainable option overall.     

Effects of extracts from Italian medicinal plants on planktonic growth, biofilm formation and adherence of methicillin-resistant Staphylococcus aureus

AIM OF STUDY: One-third of botanical remedies from southern Italy are used to treat skin and soft tissue infection (SSTI). Staphylococcus aureus, a common cause of SSTI, has generated increasing concern due to drug resistance. Many plants possess antimicrobial agents and provide effective remedies for SSTI. Our aim was to investigate plants from different ethnobotanical usage groups for inhibition of growth and biofilms in methicillin-resistant Staphylococcus aureus (MRSA). MATERIALS AND METHODS: Three groups were assessed: plant remedies for SSTI, plant remedies not involving the skin, and plants with no ethnomedical application. We screened 168 extracts, representing 104 botanical species, for activity against MRSA (ATCC 33593). We employed broth dilution methods to determine the MIC after 18 h growth using an optical density (OD 600 nm) reading. Anti-biofilm effects were assessed by growing biofilms for 40 h, then fixing and staining with crystal violet. After washing, 10% Tween 80 was added and OD 570 nm readings were taken. RESULTS: Extracts from 10 plants exhibited an IC50相似文献   

Glucagon-like peptide-1 receptor dimerization differentially regulates agonist signaling but does not affect small molecule allostery

The glucagon-like peptide-1 receptor (GLP-1R) is a family B G protein-coupled receptor and an important drug target for the treatment of type II diabetes, with activation of pancreatic GLP-1Rs eliciting glucose-dependent insulin secretion. Currently, approved therapeutics acting at this receptor are peptide based, and there is substantial interest in small molecule modulators for the GLP-1R. Using a variety of resonance energy transfer techniques, we demonstrate that the GLP-1R forms homodimers and that transmembrane helix 4 (TM4) provides the primary dimerization interface. We show that disruption of dimerization using a TM4 peptide, a minigene construct encoding TM4, or by mutation of TM4, eliminates G protein-dependent high-affinity binding to GLP-1(7-36)NH₂ but has selective effects on receptor signaling. There was <10-fold decrease in potency in cAMP accumulation or ERK1/2 phosphorylation assays but marked loss of intracellular calcium mobilization by peptide agonists. In contrast, there was near-complete abrogation of the cAMP response to an allosteric agonist, compound 2, but preservation of ERK phosphorylation. Collectively, this indicates that GLP-1R dimerization is important for control of signal bias. Furthermore, we reveal that two small molecule ligands are unaltered in their ability to allosterically modulate signaling from peptide ligands, demonstrating that these modulators act in cis within a single receptor protomer, and this has important implications for small molecule drug design.     

Clinically significant symptom change in children with attention‐deficit/hyperactivity disorder: does it correspond with reliable improvement in functioning?

This study examined the relation between clinically significant (CS) change in symptoms of attention‐deficit/hyperactivity disorder (ADHD) and of oppositional defiant disorder (ODD), and reliable change in multiple domains of functioning in children who participated in the Multimodal Treatment Study of Children with ADHD. Children with CS change in symptoms were significantly more likely than children without CS change to have reliable change across five domains of functioning. Interestingly, however, depending on the measure of functioning, 14 to 52% of children who did not achieve CS change in symptoms showed reliable improvement in functional domains. The results have implications for the definition and measurement of CS change in child treatment‐outcome studies. © 2008 Wiley Periodicals, Inc. J Clin Psychol 65:1–18, 2009.     

Histological methods for ex vivo axon tracing: A systematic review

Objectives: Axon tracers provide crucial insight into the development, connectivity, and function of neural pathways. A tracer can be characterized as a substance that allows for the visualization of a neuronal pathway. Axon tracers have previously been used exclusively with in vivo studies; however, newer methods of axon tracing can be applied to ex vivo studies. Ex vivo studies involve the examination of cells or tissues retrieved from an organism. These post mortem methods of axon tracing offer several advantages, such as reaching inaccessible tissues and avoiding survival surgeries.

Methods: In order to evaluate the quality of the ex vivo tracing methods, we performed a systematic review of various experimental and comparison studies to discern the optimal method of axon tracing.

Results: The most prominent methods for ex vivo tracing involve enzymatic techniques or various dyes. It appears that there are a variety of techniques and conditions that tend to give better fluorescent character, clarity, and distance traveled in the neuronal pathway. We found direct comparison studies that looked at variables such as the type of tracer, time required, effect of temperature, and presence of calcium, however, there are other variables that have not been compared directly.

Discussion: We conclude there are a variety of promising tracing methods available depending on the experimental goals of the researcher, however, more direct comparison studies are needed to affirm the optimal method.