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Reports on Progress in Physics.... Jun 2022Bacteria are among the oldest and most abundant species on Earth. Bacteria successfully colonize diverse habitats and play a significant role in the oxygen, carbon, and... (Review)
Review
Bacteria are among the oldest and most abundant species on Earth. Bacteria successfully colonize diverse habitats and play a significant role in the oxygen, carbon, and nitrogen cycles. They also form human and animal microbiota and may become sources of pathogens and a cause of many infectious diseases. Suspensions of motile bacteria constitute one of the most studied examples of active matter: a broad class of non-equilibrium systems converting energy from the environment (e.g., chemical energy of the nutrient) into mechanical motion. Concentrated bacterial suspensions, often termed active fluids, exhibit complex collective behavior, such as large-scale turbulent-like motion (so-called bacterial turbulence) and swarming. The activity of bacteria also affects the effective viscosity and diffusivity of the suspension. This work reports on the progress in bacterial active matter from the physics viewpoint. It covers the key experimental results, provides a critical assessment of major theoretical approaches, and addresses the effects of visco-elasticity, liquid crystallinity, and external confinement on collective behavior in bacterial suspensions.
Topics: Animals; Bacteria; Elasticity; Motion; Suspensions; Viscosity
PubMed: 35605446
DOI: 10.1088/1361-6633/ac723d -
Journal of Materials Chemistry. B Dec 2020Natural dispersants and flocculants, often referred to as dispersion stabilizers and liquid-solid separators, respectively, have secured a promising role in the... (Review)
Review
Natural dispersants and flocculants, often referred to as dispersion stabilizers and liquid-solid separators, respectively, have secured a promising role in the bioprocessing community. They have various applications, including in biomedicine and in environmental remediation. A large fraction of existing dispersants and flocculants are synthesized from non-safe chemical compounds such as polyacrylamide and surfactants. Despite numerous advantages of synthetic dispersants and flocculants, issues such as renewability, sustainability, biocompatibility, and cost efficiency have shifted attention towards natural homologues, in particular, cellulose-based ones. Within the past decade, cellulose derivatives, obtained via chemical and mechanical treatments of cellulose fibrils, have successfully been used for these purposes. In this review article, by dividing the functional cellulosic compounds into "polymeric" and "nanoscale" categories, we provide insight into the engineering pathways, the structural frameworks, and surface chemistry of these "green" types of dispersants and flocculants. A summary of their efficiency and the controlling parameters is also accompanied by recent advances in their applications in each section. We are confident that the emergence of cellulose-based dispersing and flocculating agents will extend the boundaries of sustainable green technology.
Topics: Adsorption; Cellulose; Flocculation; Nanoparticles; Static Electricity; Suspensions
PubMed: 33136107
DOI: 10.1039/d0tb02021d -
Academic Pediatrics Aug 2022Individual-, school-, and neighborhood-level support and connectedness may help to mitigate against school suspensions, which have profound health and social...
INTRODUCTION
Individual-, school-, and neighborhood-level support and connectedness may help to mitigate against school suspensions, which have profound health and social consequences. Most research on social connectedness and suspension has focused only on school connectedness, and much less is known about the effects of individual social support and neighborhood-level connectedness on suspension.
METHODS
We examined associations between all three levels of connectedness and suspension in a cross-sectional analysis of a population-based youth sample in Allegheny County, Pennsylvania. The Healthy Allegheny Teen Survey, a county-wide survey of 1813 male and female youth ages 14 to 19, assessed health risk/protective behaviors through random-digit-dialing in 2014. This survey included validated items evaluating each type of support as well as items assessing lifetime history of suspension. Logistic regression models examined associations between suspension and social support, school connectedness, and neighborhood-level cohesion.
RESULTS
In fully adjusted logistic regression models examining associations between suspension and each type of support, youth with high social support had 0.38 times the odds of school suspension compared to youth with low social support (95% confidence interval [CI] 0.19-0.74). High levels of school connectedness and neighborhood-level cohesion were also associated with significantly lower odds of suspension (odds ratio [OR] 0.31, 95% CI 0.18-0.53; OR 0.28, 95% CI 0.16-0.47, respectively). Examining all 3 types of support jointly, school connectedness and neighborhood-level cohesion were significantly inversely related to suspension (OR 0.41, 95% CI 0.24-0.71; OR 0.41, 95% CI 0.23-0.74, respectively).
CONCLUSIONS
Programs that foster connectedness at the individual-, school-, and neighborhood-level may help reduce school suspension.
Topics: Adolescent; Cross-Sectional Studies; Female; Humans; Male; Schools; Social Support; Students; Suspensions; Young Adult
PubMed: 34929388
DOI: 10.1016/j.acap.2021.12.016 -
Methods in Molecular Biology (Clifton,... 2022Suspension cell lines grow free-floating in the cell culture media without any attachment to the culture plate/vessel. Suspension cells typically mimic cells that exist...
Suspension cell lines grow free-floating in the cell culture media without any attachment to the culture plate/vessel. Suspension cells typically mimic cells that exist in the circulation of multicellular animals such as mouse and humans. Generally, cell lines derived from the blood such as lymphocytes, megakaryocyte, and neutrophils grow in suspension. These cell lines can be used for experimental studies to understand the biology/biochemistry of cancer cells. In this chapter, procedures for working with suspension cell lines are provided, including protocols for thawing, culturing, and cryopreserving cancer cell lines. Importantly, this chapter demonstrates the best practices required to work with suspension cell lines, to minimize the risk of contaminations from adventitious microorganisms or from other cell lines.
Topics: Animals; Cell Culture Techniques; Cell Line; Mice; Neoplasms; Suspensions
PubMed: 35737229
DOI: 10.1007/978-1-0716-2376-3_2 -
Current Drug Delivery 2016In the last three decades, nano-sizing of hydrophobic drugs has emerged as one of the most commonly used strategies to overcome their solubility and bioavailability... (Review)
Review
In the last three decades, nano-sizing of hydrophobic drugs has emerged as one of the most commonly used strategies to overcome their solubility and bioavailability related issues. Nanosuspensions offer versatile features and unique advantages over other approaches that have been utilized for this purpose. The unique inherent properties of nanosuspensions have been explored for a wide variety of applications. Commercial production of stable nanosuspensions has been made possible by the use of techniques such as media milling and high pressure homogenization. This article reviews various techniques being employed for production, characterization, merits and limitations of nanosuspensions and mechanisms that play a role in the physicochemical stability of nanosuspensions. The common strategies applied so far to overcome their stability and commercialization related aspects are also highlighted.
Topics: Animals; Drug Stability; Humans; Nanoparticles; Suspensions
PubMed: 26721266
DOI: 10.2174/1567201813666160101120452 -
Infant Mental Health Journal Nov 2021Expulsion presents a significant risk in Early Care and Education (ECE) settings due to its association with early disadvantage and frequency of use. A statewide survey...
Expulsion presents a significant risk in Early Care and Education (ECE) settings due to its association with early disadvantage and frequency of use. A statewide survey was conducted to characterize ECE suspension and expulsion (S/E) in Colorado. Child, program, and community-level factors were examined as predictors of S/E, alongside preventative intervention supports capable of reducing S/E. Six hundred and sixty three licensed child care programs participated in the survey, providing information on 19,848 enrolled children, 312 suspensions, and 74 expulsions. A series of multilevel hierarchical regressions were conducted, examining predictors for S/E. Children with IEPs/IFSPs were disproportionately suspended; 2-3-year-olds were disproportionately expelled; and boys, 5-6-year-olds, and children with disabilities were disproportionately suspended and expelled. Center-based programs, lower quality ratings, and "zero tolerance" policies predicted greater use of suspension. In contrast, school-district affiliation and knowledge of how to access infant and early childhood mental health consultation (IECMHC) decreased suspension. Lower levels of regional child poverty predicted higher use of expulsion. Affiliation with a school-district, IECMH consultant-led training, and use of quality coaches predicted decreased expulsion. This study identifies the need for ongoing protection for children with IEPs/ IFSPs and the preventative interventions that mitigate risk for S/E.
Topics: Child; Child Poverty; Child, Preschool; Colorado; Humans; Infant; Male; Men; Mental Health; Suspensions
PubMed: 34587311
DOI: 10.1002/imhj.21944 -
Advanced Healthcare Materials Apr 2022The extrusion printing of inks into suspension baths is an exciting tool, as it allows the printing of diverse and soft hydrogel inks into 3D space without the need for...
The extrusion printing of inks into suspension baths is an exciting tool, as it allows the printing of diverse and soft hydrogel inks into 3D space without the need for layer-by-layer fabrication. However, this printing process is complex and there have been limited studies to experimentally and computationally characterize the process. In this work, hydrogel inks (i.e., gelatin methacrylamide (GelMA)), suspension baths (i.e., agarose, Carbopol), and the printing process are examined via rheological, computational, and experimental analyses. Rheological data on various hydrogel inks and suspension baths is utilized to develop computational printing simulations based on Carreau constitutive viscosity models of the printing of inks within suspension baths. These results are then compared to experimental outcomes using custom print designs where features such as needle translation speed, defined in this work as print speed, are varied and printed filament resolution is quantified. Results are then used to identify print parameters for the printing of a GelMA ink into a unique guest-host hyaluronic acid suspension bath. This work emphasizes the importance of key rheological properties and print parameters for suspension bath printing and provides a computational model and experimental tools that can be used to inform the selection of print settings.
Topics: Baths; Bioprinting; Computer Simulation; Gelatin; Hydrogels; Ink; Printing, Three-Dimensional; Suspensions
PubMed: 34699689
DOI: 10.1002/adhm.202101679 -
Current Pharmaceutical Design 2018Discovery and development of BCS class 1 drugs through high throughput screening is one of the biggest challenge faced by formulation scientist. (Review)
Review
BACKGROUND
Discovery and development of BCS class 1 drugs through high throughput screening is one of the biggest challenge faced by formulation scientist.
METHODS
There are a number of approaches that have been exploited to enhance the solubility and permeability of drugs. Among them, development of nanosuspension has offered several benefits. These techniques may increase effective surface area due to nanonization of drug particles and further increases saturation solubility and dissolution properties for improved bioavailability. Various development methods are patented which are cost effective and easy to scale up.
CONCLUSION
Several unique features of nanosuspension make it a versatile delivery system for different routes of administration including oral, dermal, ocular, parenteral and pulmonary. The present review is focused on preparatory techniques and formulation considerations of nanosuspension. Brief information about evaluation parameters, applications of nanosuspension in drug delivery and patented and marketed products available is also discussed.
Topics: Biological Availability; Drug Delivery Systems; Nanoparticles; Nanotechnology; Solubility; Suspensions
PubMed: 29788880
DOI: 10.2174/1381612824666180522100251 -
Journal of Visualized Experiments : JoVE Sep 2023Kidney organoids can be generated from induced pluripotent stem cells (iPSCs) through various approaches. These organoids hold great promise for disease modeling, drug...
Kidney organoids can be generated from induced pluripotent stem cells (iPSCs) through various approaches. These organoids hold great promise for disease modeling, drug screening, and potential therapeutic applications. This article presents a step-by-step procedure to create kidney organoids from iPSCs, starting from the posterior primitive streak (PS) to the intermediate mesoderm (IM). The approach relies on the APEL 2 medium, which is a defined, animal component-free medium. It is supplemented with a high concentration of WNT agonist (CHIR99021) for a duration of 4 days, followed by fibroblast growth factor 9 (FGF9)/heparin and a low concentration of CHIR99021 for an additional 3 days. During this process, emphasis is given to selecting the optimal cell density and CHIR99021 concentration at the start of iPSCs, as these factors are critical for successful kidney organoid generation. An important aspect of this protocol is the suspension culture in a low adherent plate, allowing the IM to gradually develop into nephron structures, encompassing glomerular, proximal tubular, and distal tubular structures, all presented in a visually comprehensible format. Overall, this detailed protocol offers an efficient and specific technique to produce kidney organoids from diverse iPSCs, ensuring successful and consistent results.
Topics: Animals; Induced Pluripotent Stem Cells; Kidney; Nephrons; Kidney Glomerulus; Suspensions; Organoids
PubMed: 37677041
DOI: 10.3791/65698 -
Advances in Colloid and Interface... Jan 2023Multiphase displacement in porous media can be adjusted by micro/nanoparticle suspensions, which is widespread in many scientific and industrial contexts. Direct... (Review)
Review
Multiphase displacement in porous media can be adjusted by micro/nanoparticle suspensions, which is widespread in many scientific and industrial contexts. Direct visualization of suspension flow dynamics and corresponding multiphase patterns is crucial to understanding displacement mechanisms and eventually optimizing these processes in geological, biological, chemical, and other engineering systems. However, suspension flow inside the opaque realistic porous media makes direct observation challenging. The advances in microfluidic experiments have provided us with alternative methods to observe suspension influence on the interface and multiphase flow behaviors at high temporal and spatial resolutions. Macroscale processes are controlled by microscale interfacial behaviors, which are affected by multiple physical factors, such as particle adsorption, capillarity, and hydrodynamics. These properties exerted on the suspension flow in porous media may lead to interesting interfacial phenomena and new displacement consequences. As an underpinning science, understanding and controlling the suspension transport process from interface to flow patterns in porous media is critical for a lower operating cost to improve resource production while reducing harmful emissions and other environmental impacts. This review summarizes the basic properties of different micro/nanoparticle suspensions and the state-of-the-art microfluidic techniques for displacement research activities in porous media. Various suspension transport behaviors and displacement mechanisms explored by microfluidic experiments are comprehensively reviewed. This review is expected to boost both experimental and theoretical understanding of suspension transport and interfacial interaction processes in porous media. It also brings forward the challenges and opportunities for future research in controlling complex fluid flow in porous media for diverse applications.
Topics: Microfluidics; Porosity; Suspensions; Hydrodynamics; Nanoparticles
PubMed: 36528919
DOI: 10.1016/j.cis.2022.102826