Poor concentration

Children with ADHD often have difficulty giving close attention to details. However, it is wrong to believe that children with ADHD cannot concentrate at all. Their mechanisms for concentrating are inefficient and unreliable, not absent. Difficulties with concentration result in children with ADHD often being confused and unable to understand instructions, and attentional difficulties may give children with ADHD an unfocused appearance. Often, children with ADHD have difficulty in adjusting their level of attention to suit the situation. This chapter discusses poor concentration in children with ADHD. It includes the attentional processes (internal and external) in the brain, and difficult tasks for attentional mechanisms.

Effects of salinity on solid particle settling velocity in non-Newtonian Herschel–Bulkley fluids

Settling velocity or depositional velocity is considered a key parameter to account for in the drilling technology of oil and gas wells as well as hydrocarbon processing since an accurate estimation of this parameter allows the transport of cuttings efficiently, avoids non-productive time, and helps avoid costly problems. Understanding the settling velocity in fluid with high salinity will help for the better separation of oil and natural gas streams in processing facilities. Although a great amount of effort was given to rheology and settling velocity measurements for power-law fluid and Bingham fluids, there are limited studies available in the literature for Herschel–Bulkley (H–B) fluid with salinity. The present study analyzes the fluid rheology of non-Newtonian fluids with, and without, salinity. Moreover, experiments have been conducted to measure the settling velocity of different diameters of solid particles through Herschel–Bulkley fluids with various salinity conditions. For the rheology analysis, it is found that higher weight percentages of NaCl lead to low values of shear stresses. As well, higher weight percentages of CaCl2 concentration result in a slight increase in shear stresses per a given shear rate. On the other hand, higher percentages of salt concentration cause an increase in the terminal velocity.

Controlled electrospray generation of non-spherical alginate microparticles

Electrospraying is a technique used to generate microparticles in a high throughput manner. For biomedical applications, a biocompatible electrosprayed material is often desirable. Using polymers, such as alginate hydrogels, makes it possible to create biocompatible and biodegradable microparticles that can be used for cell encapsulation, to be employed as drug carriers, and for use in 3D cell culturing. Evidence in the literature suggests that the morphology of the biocompatible microparticles is relevant in controlling the dynamics of the microparticles in drug delivery and 3D cell culturing applications. Yet, most electrospray-based techniques only form spherical microparticles, and there is currently no widely adopted technique for producing non-spherical microparticles at a high throughput. Here, we demonstrate the generation of non-spherical biocompatible alginate microparticles by electrospraying, and control the shape of the microparticles by varying experimental parameters such as chemical concentration and the distance between the electrospray tip and the particle-solidification bath. Importantly, we show that these changes to the experimental setup enable the synthesis of different shaped particles, and the systematic change in parameters, such as chemical concentration, result in monotonic changes to the particle aspect ratio. We expect that these results will find utility in many biomedical applications that require biocompatible microparticles of specific shapes.

ANTIFUNGAL ACTIVITY OF MANGIFERA INDICA LEAF EXTRACT ON FUNGI ISOLATED FROM BREAD VENDED WITHIN BAKORI, NIGERIA

Objective: The present study was carried out to determine the antifungal activity of Mangifera indica leaves extract on fungi isolated from bread vended within Bakori. Methods: The powdered form of M. indica leaves was used to prepare the extract using ethanol, the leaves were air dried at room temperature for 10 days. Results: The chemical test was carried out to identify the secondary metabolites, some of the metabolites that were present include alkaloids, saponins, flavonoids, steroids, and tannins. Both fungal isolates were identified on the basis of morphological characteristics as Aspergillus niger, Aspergillus flavus, and Mucor spp. The antifungal activity of M. indica leaves extract was determined using agar well diffusion method on Aspergillus and Mucor spp. The results showed that the extract was found to inhibit A. niger at 100 mg/ml, 50 mg/ml, and 25 mg/ml with 13.9 mm, 11.5 mm, and 8.0 mm, respectively, and A. flavus at 100 mg/ml, 50 mg/ml, and 25 mg/ml with 13.6 mm, 11.2 mm, and 8.1 mm, respectively, while Mucor spp. was found to be resistant at 25 mg/ml while 100 mg/ml and 50 mg/ml showed an activity. Minimum inhibitory concentration result showed a promising activity against Aspergillus spp. at 25 mg/ml while Mucor spp. at 50 mg/ml. Conclusion: Therefore, M. indica leaf extracts can be used in the treatment of diseases or illness caused by Aspergillus and Mucor spp.

A peptide of a type I toxin−antitoxin system inducesHelicobacter pylorimorphological transformation from spiral shape to coccoids

Toxin−antitoxin systems are found in many bacterial chromosomes and plasmids with roles ranging from plasmid stabilization to biofilm formation and persistence. In these systems, the expression/activity of the toxin is counteracted by an antitoxin, which, in type I systems, is an antisense RNA. While the regulatory mechanisms of these systems are mostly well defined, the toxins’ biological activity and expression conditions are less understood. Here, these questions were investigated for a type I toxin−antitoxin system (AapA1−IsoA1) expressed from the chromosome of the human pathogenHelicobacter pylori. We show that expression of the AapA1 toxin inH. pyloricauses growth arrest associated with rapid morphological transformation from spiral-shaped bacteria to round coccoid cells. Coccoids are observed in patients and during in vitro growth as a response to different stress conditions. The AapA1 toxin, first molecular effector of coccoids to be identified, targetsH. pyloriinner membrane without disrupting it, as visualized by cryoelectron microscopy. The peptidoglycan composition of coccoids is modified with respect to spiral bacteria. No major changes in membrane potential or adenosine 5′-triphosphate (ATP) concentration result from AapA1 expression, suggesting coccoid viability. Single-cell live microscopy tracking the shape conversion suggests a possible association of this process with cell elongation/division interference. Oxidative stress induces coccoid formation and is associated with repression of the antitoxin promoter and enhanced processing of its transcript, leading to an imbalance in favor of AapA1 toxin expression. Our data support the hypothesis of viable coccoids with characteristics of dormant bacteria that might be important inH. pyloriinfections refractory to treatment.

Fused Gromov-Wasserstein Distance for Structured Objects

Optimal transport theory has recently found many applications in machine learning thanks to its capacity to meaningfully compare various machine learning objects that are viewed as distributions. The Kantorovitch formulation, leading to the Wasserstein distance, focuses on the features of the elements of the objects, but treats them independently, whereas the Gromov–Wasserstein distance focuses on the relations between the elements, depicting the structure of the object, yet discarding its features. In this paper, we study the Fused Gromov-Wasserstein distance that extends the Wasserstein and Gromov–Wasserstein distances in order to encode simultaneously both the feature and structure information. We provide the mathematical framework for this distance in the continuous setting, prove its metric and interpolation properties, and provide a concentration result for the convergence of finite samples. We also illustrate and interpret its use in various applications, where structured objects are involved.

Might limiting liquid nicotine concentration result in more toxic electronic cigarette aerosols?

Some jurisdictions have instituted limits on electronic cigarette (ECIG) liquid nicotine concentration, in an effort to control ECIG nicotine yield, and others are considering following suit. Because ECIG nicotine yield is proportional to the product of liquid nicotine concentration (milligram per millilitre) and device power (watts) regulations that limit liquid nicotine concentration may drive users to adopt higher wattage devices to obtain a desired nicotine yield. In this study we investigated, under various hypothetical regulatory limits on ECIG liquid nicotine concentration, a scenario in which a user of a common ECIG device (SMOK TF-N2) seeks to obtain in 15 puffs the nicotine emissions equivalent to one combustible cigarette (ie, 1.8 mg). We measured total aerosol and carbonyl compound (CC) yields in 15 puffs as a function of power (15–80 W) while all else was held constant. The estimated nicotine concentration needed to achieve combustible cigarette-like nicotine yield at each power level was then computed based on the measured liquid consumption. We found that for a constant nicotine yield of 1.8 mg, reducing the liquid nicotine concentration resulted in greater amount of liquid aerosolised (p<0.01) and greater CC emissions (p<0.05). Thus, if users seek a given nicotine yield, regulatory limits on nicotine concentration may have the unintended consequence of increasing exposure to aerosol and respiratory toxicants. This outcome demonstrates that attempting to control ECIG nicotine yield by regulating one factor at a time may have unintended health effects and highlights the need to consider multiple factors and outcomes simultaneously when designing regulations.

Quantitative modeling of the function of kinetically driven transcriptional riboswitches

We propose a generalized modeling framework for the kinetic mechanisms of transcriptional riboswitches. The formalism accommodates time-dependent transcription rates and changes of metabolite concentration and permits incorporation of variations in transcription rate depending on transcript length. We derive explicit analytical expressions for the fraction of transcripts that determine repression or activation of gene expression, pause site location and its slowing down of transcription for the case of the (2’dG)-sensing riboswitch from Mesoplasma florum. Our modeling challenges the current view on the exclusive importance of metabolite binding to transcripts containing only the aptamer domain. Numerical simulations of transcription proceeding in a continuous manner under time-dependent changes of metabolite concentration further suggest that rapid modulations in concentration result in a reduced dynamic range for riboswitch function regardless of transcription rate, while a combination of slow modulations and small transcription rates ensures a wide range of finely tuneable regulatory outcomes.

Impact of Triazole Therapeutic Drug Monitoring Availability and Timing

ABSTRACT Therapeutic drug monitoring (TDM) is an established strategy to optimize antifungal therapy with certain triazoles. While established relationships exist between concentration and safety or efficacy, the impact of TDM timing on outcomes is unknown. We report clinical outcomes, including antifungal exposure and mortality, in patients receiving institutional versus reference laboratory TDM. The availability of in-house triazole assays reduced the time to drug concentration result (12 versus 68 h; P < 0.001) and time to achieve therapeutic serum concentrations (10 versus 31 days; P < 0.001). Subtherapeutic concentrations were associated with higher patient mortality (32% versus 13.3%; P = 0.036).