Academic literature on the topic 'Viruses, osmotic pressure'

The kinetics of the fusion process of unsealed and resealed erthyrocyte ghosts with influenza virus (A/PR8/34, A/Chile 1/83), were measured under hypotonic, isotonic and hypertonic conditions using a recently developed fluorescence assay (Hoekstra et al. (1984) Biochemistry23:5675–5681]. No correlation between the external osmotic pressure and kinetics and extent of fusion was observed. Influenza viruses fuse as effectively with unsealed ghosts as with resealed ghosts. It is concluded that osmotic forces as well as osmotic swelling of cells are not necessary for virus-cell membrane fusion.

Non-immune hydrops fetalis is a severe fetal condition defined as the excessive accumulation of fetal fluid within the fetal extravascular compartments and body cavities. The prevalence of non-immune hydrops fetalis is unknown. Currently, about 90% of cases of hydrops fetalis are non-immune hydrops fetalis. Non-immune hydrops fetalis causes are multi-factorial. The pathophysiological mechanism of non-immunologic hydrops fetalis is related to abnormal fluid transportation between plasma and tissues. This is due to the increase in hydrostatic capillary pressure and capillary permeability and a reduction of the plasma osmotic pressure or lymphatic flow. A variety of viral infection agents have been associated with non-immune hydrops fetalis like parvovirus B19, herpes simplex virus, cytomegalovirus, Toxoplasma gondii, Treponema pallidum, but even other viruses that attack the maternal and fetus during pregnancy cannot be excluded as possible causes of non-immune hydrops fetalis. We present one case of non-immune hydrops fetalis who was diagnosed intra-uterine, three weeks after recovery from Coronavirus disease (COVID-19). After much investigation, we could not find any known factor that may be the cause of non-immunologic hydrops fetalis. Therefore, we predisposed a possible causal connection between nonimmunologic hydrops fetalis and Coronavirus disease (COVID-19).

Abstract Background and purpose Virus-containing aerosol droplets emitted by breathing, speech or coughing dry rapidly to equilibrium with ambient relative humidity (RH), increasing in solute concentration with effects on virus survival and decreasing in diameter with effects on sedimentation and respiratory uptake. The aim of this paper is to model the effect of ionic and macromolecular solutes on droplet drying and solute concentration. Methods Deliquescence-efflorescence concepts and Kohler theory were used to simulate the evolution of solute concentrations and water activity in respiratory droplets, starting from efflorescence data on mixed NaCl/KCl aerosols and osmotic pressure data on respiratory macromolecules. Results In NaCl/KCl solutions total salt concentrations were shown to reach 10-13 M at the efflorescence RH of 40-55%, depending on the K:Na ratio. Dependence on K:Na ratio implies that the evaporation curves differ between aerosols derived from saliva and from airway surfaces. The direct effect of liquid droplet size through the Kelvin term was shown to be smaller and restricted to the evolution of breath emissions. Modelling the effect of proteins and glycoproteins showed that salts determine drying equilibria down to the efflorescence RH, and macromolecules at lower RH. Conclusion Differences in solute composition between airway surfaces and saliva are predicted to lead to different drying behaviour of droplets emitted by breathing, speech and coughing. These differences may influence the inactivation of viruses.

Острые кишечные инфекции остаются одной самых актуальных проблем педиатрии в связи с высоким уровнем заболеваемости, развитием тяжелых форм и летальности, особенно у детей первых пяти лет жизни. В большинстве случаев тяжесть заболевания обусловлена развитием эксикоза, в основе которого лежат потери электролитов и жидкости в следствии эметического и диарейного синдромов. Однако существуют различия в механизмах формирования дегидратации в зависимости от вида инфекционного агента. Так при дегидратации, вызванной вирусами, в основе лежит механизм нарушения абсорбции, причиной которого являются дистрофические изменения в энтероцитах и уменьшение количества клеток, способных адсорбировать жидкость из кишечника. Повышение осмотического давления в процессе нарушенной ферментации нерасщепленных дисахаридов приводит к перемещению воды в просвет кишечника и объясняет появление осмотической диареи и, как следствие, тяжелой дегидратации при отсутствии своевременной коррекции данного патологического состояния. При внедрении бактериальных кишечных патогенов, происходит воздействие различных энтеротоксинов на мембранные комплексы. В частности, стимулируется выработка медиаторов воспаления, повышается уровень внутриклеточного циклического аденозинмонофосфата или циклического гуанозинмонофосфата или происходит нарушение проницаемости слизистой оболочки кишечника под влиянием специфических белков инвазивных патогенов и в целом изменение активности нормального процесса обмена ионов. В статье так же рассмотрены альтернативные механизмы развития диареи при участии энтероэндокринно-нейронных рефлексов, а также описаны типы дегидратации с детализацией водно-электролитных нарушений и современные подходы к регидратационной терапии. Знание и понимание особенностей патогенеза, диагностики типа дегидратации необходимо практикующему врачу для выбора тактики патогенетической терапии острых кишечных инфекций у детей. Acute intestinal infections are one of the most urgent challenges in pediatrics due to a high morbidity, development of severe forms and mortality, especially in children under five years. In most cases, severity of the disease is due to development of exicosis induced by loss of electrolytes and fluids as a result of emetic and diarrheal syndromes. However, the mechanisms of dehydration differ depending on the type of infectious agent. Thus, dehydration caused by viruses is due to the mechanism of absorption disorders induced by dystrophic changes in enterocytes and reduced number of cells that could absorb fluid from the intestine. The increase in osmotic pressure under disturbed fermentation of unsplit disaccharides results in translocation of water into the intestinal lumen, which explains the development of osmotic diarrhea and ensuing severe dehydration in the absence of timely correction of this pathological condition. After invasion of bacterial intestinal pathogens, various enterotoxins impact membrane complexes. Specifically, production of inflammatory mediators is stimulated, levels of intracellular cyclic adenosine monophosphate or cyclic guanosine monophosphate increase, or specific proteins of invading pathogens affect the permeability of intestinal mucosa and, eventually, change the activity of normal ion exchange process. The article also addresses alternative mechanisms of diarrhea involving enteroendocrine-neural reflexes and focuses on types of dehydration with a detailed description of water-electrolyte disorders and modern approaches to rehydration therapy. Knowledge and understanding of the pathogenetic and diagnostic features specific for a dehydration type are necessary for practitioners to choose the tactics for pathogenetic therapy of children’s acute intestinal infections. The aim of this review was to summarize modern aspects of the pathogenesis of exicosis syndrome in acute intestinal infections in young children.

Ideally, pressure driven membrane processes used in wastewater treatment such as reverse osmosis and nanofiltration should provide a complete physical barrier to the passage of pathogens such as enteric viruses. In reality, manufacturing imperfections combined with membrane ageing and damage can result in breaches as small as 20 to 30 nm in diameter, sufficient to allow enteric viruses to contaminate the treated water and compromise public health. In addition to continuous monitoring, frequent demonstration of the integrity of membranes is required to provide assurance that the barrier to the passage of such contaminants is intact. Existing membrane integrity monitoring systems, however, are limited and health regulators typically credit high-pressure membrane systems with only 2 log10 virus rejection, well below their capability. A reliable real-time method that can recognize the true rejection potential of membrane systems greater than 4 log10 has not yet been established. This review provides a critical evaluation of the current methods of integrity monitoring and identifies novel approaches that have the potential to provide accurate, representative virus removal efficiency estimates.

Abstract This paper presents methodology, concept and results of the WateReuse Foundation project WFR – 09 – 06b when developing a high pressure membrane, reverse osmosis (RO) and nanofiltration (NF) online membrane integrity testing (MIT) technique. The use of pressure-driven membrane processes, particularly RO, has grown significantly over the past few decades in water treatment and reuse applications to safeguard water supplies against harmful pathogens and impurities. In principle, RO membranes should provide a complete physical barrier to the passage of nanosize pathogens (e.g., enteric viruses). However, in the presence of imperfections and/or membrane damage, membrane breaches as small as 20 to 30 nm can allow enteric viruses to pass through the membrane and contaminate the product water stream, thereby posing a potential health hazard that is of particular concern for potable water production. This project was focused on evaluating a pulsed-marker membrane integrity monitoring (PM-MIMo) approach for RO processes on the basis of the use of a fluorescent marker. The monitoring approach employs pulsed dosing (via a precision metering pump) of a marker into the RO feed stream coupled with online marker concentration monitoring in the RO permeate by an inline spectrofluorometer. Membrane integrity is then inferred on the basis of real-time analysis of the marker permeate time − profile concentration in response. The basic concept of the PM-MIMo approach for detecting membrane breaches was successfully demonstrated, by comparing intact and damaged membranes, in a series of experiments using a diagnostic plate-and-frame RO system and spiral-wound RO pilot system. Results of the developed technique are presented in the project report to allow the industry to consider adopting this technique for RO/NF online integrity monitoring.

Ex-mining pond water is widely used for the daily needs of the people these days, such as bathing, washing, and even drinking. Over time, it turns out that coal mine acid water has polluted the environment. The use of membrane technology to produce water that meets drinking water quality standards by the Minister of Health Regulation No. 492 of 2010 can be a solution to this problem. The NF270 membrane is a membrane process between reverse osmosis and ultrafiltration, which has a lower flux and operating pressure below 0.2-1.53 Mpa compared to reverse osmosis. Membrane NF270 is used for the reclamation of wastewater, water purification and softening, seawater desalination, and others. Its high rejection of organic molecules with a molecular weight of 200-2000 Da ions and multivalent can remove suspended solids, natural organic matter, bacteria, viruses, salts, and divalent ions contained in water, including coal mine acid water. The purpose of treating acid mine drainage with the NF270 membrane is to remove COD, TSS, TDS, and Fe metals. The NF270 membrane was used in this study to treat the coal mine acid water of PT. Bukit Asam. The performance of the NF270 process was assessed from the effect of pressure (4, 5, and 6 bar) on the flux and rejection rate of each parameter in a single solution, mixed and aqueous coal mine acid solution. The optimum pressure of the NF270 membrane for all parameters was 6 bar. This optimum pressure was then used to compare the phenomenon of flux that occurred and the level of rejection produced in the original sample of coal mine acid water. In the original coal mine acid water, there was a significant decrease in flux due to fouling deposition on the membrane surface. This phenomenon of decreasing flux was caused by fouling and polarization concentration. The rejection rates produced for the parameters of COD, TSS, TDS, and Fe with NF270 membranes were 56.4-93.1%; 78.5-100%; 43-69.3%; 67-100% respectively. Treated coal mine acid water using NF270 membrane technology can be used as drinking water that meets the standards of the Indonesian Ministry of Health Regulation. Thus, NF270 membrane technology can be used to process coal mine acid water into environmentally friendly drinking water.

Brownian motion is small particles suspended in a liquid tend to move in pseudorandom or stochastic paths through the liquid, even if the liquid in question is inert. By Einstein's theories for Brownian motion referring to the 1905 works, equilibrium relations and viscous friction, osmotic pressure reaching the diffusion coefficient of Brownian particles. In the fluid medium, we will address the deviation (diffusion equation and basically the relationship between the mean square deviation of the particle position and the fluid temperature, the higher the temperature, the greater the mean square deviation, that is, directly proportional to the constant of the diffusion). The importance of this study is the movement of particles and molecules in the fluid medium, whether these molecules are lipids, proteins, we know that viruses and bacteria are having a certain movement in the organism and its systems, we will tend to study their movement within vessels and between fluids body, with two densities and particular conditions, knowing the likely displacement, we will know therapeutic interventions that are probably more effective. The aim of this work is to demonstrate through mathematical applications the Brownian motion.

At the most basic level viruses are biological nano-containers constituted by genetic material enclosed in a protein shell, capsid. A peculiar feature of viruses, both bacterial and some eukaryotic viruses, lies in the high packaging density of the genome in order to fit itself in the small capsid and hence the high internal osmotic pressure. Virus is a relatively stable particle equipped with fascinating mechanical properties of the capsid that are crucial for the virus lifecycle. Viruses have only one purpose: infect a host cell for reproducing themselves in order to generate new viral progeny (Roos et al. 2007). Therefore, the first and foremost consideration arising from the concept of virus reflects its pathogenesis and virulence that can ultimately result in many important infectious diseases such as common cold, influenza, hepatitis, rabies, measles, cancer and AIDS. As a consequence, pathogenic viruses represent a heavy hurdle for the global health and there is a strong need for developing robust strategies such as vaccines or antiviral drugs against virus infections (Baram- Pinto et al. 2010). On the other hand, viruses in the course of evolution have become efficient specialized gene delivery agents. Therefore they represent powerful tools in biomedicine for gene therapy and vaccine purposes (Schaffer et al. 2008). For successful gene therapy and immunization programs, the efficiency and stability of viral vectors are fundamental aspects (Jorio et al. 2006). To address this challenge, in the present research project we have investigated the interaction between viruses and nanomaterials. In the last years materials on the nanoscale for their unique properties have provided a broad range of potential biomedical uses (Verma et al. 2008) and for that reason we decided to explore their application with viruses. More specifically, we have examined three types of sulfonate- functionalized gold nanoparticles (AuNPs), namely, MUS:OT, MUS and MUS:brOT NPs, which are less than 5 nm in size, negatively charged and poorly cytotoxic (Verma et al. 2008). The NPs are coated with self-assembled monolayer (SAM) of thiolated organic molecules and one of the ligand is a sulfonated molecule, MUS (Verma et al. 2008). The MUS ligand itself was tested in our experiments as well. As virus models we focused on human recombinant adenovirus type 5 (Ad), one of the most promising viral vector as vaccine and gene therapy carrier and two picornaviruses of the genus enterovirus, namely, EV1 and CVB3, important human pathogens associated with several infectious diseases (e.g. myocarditis, aseptic meningitis, encephalitis, paralysis)(Kossila et al. 2002)(Marjomäki et al. 2014a). In spite of their medical impact, there are no therapeutic treatments available against picornavirus infections and the only vaccine products are against three types of poliovirus and hepatitis A virus (Merilahti et al. 2012). Two sets of experiments were carried out: (1) Short-term incubation of Ad with nanomaterials for 1 h at 37°C prior transducing HeLa cells or before in vivo administration in zebrafish and mice. The results demonstrated that Ad shortly pre-treated with nanomaterials showed a significant increase in the gene expression in vitro and in vivo The NPs’enhanced adenovirus transduction aims to reduce Ad vector doses in vivo thereby minimizing the adverse reactions of the immune response due to high vector dosage; (2) Long-term thermostabilization studies of Ad, EV1 and CVB3 in vitro in the presence and in the absence of our nanomaterials and other substances such as sugars (sucrose, glucose, glycerol) and Polyethylene glycol (PEG) molecules at 37°C or room temperature for extensive periods of time. Our results showed the capability of the nanomaterials and sucrose to increase substantially the heat stability of the viruses. In order to elucidate the thermal inactivation mechanism of viral particles and the stabilizing effect provided by some compounds on viruses we set out to formulate an analytical theory. This line of research fits in the context of developing more thermo-stable viral vector preparations for vaccine purposes that do not require the maintenance of the challenging cold chain system in order to preserve the effectiveness of viral vaccines during the storage, shipment and administration to the patients and hence to ensure the success of global immunization programs (Alcock et al. 2010).

Reverse osmosis and nanofiltration membranes remove colloids, macromolecules, salts, bacteria and even some viruses from water. In crossflow filtration, contaminated water is driven parallel to the membrane, and clean permeate passes through. A large pressure gradient exists across the membrane, with permeate flow rates two to three orders of magnitude smaller than that of the crossflow. Membrane filtration is hindered by two mechanisms, concentration polarization and caking. During filtration, the concentration of rejected particles increases near the membrane surface, forming a concentration polarization layer. Both diffusive and convective transport drive particles back into the bulk flow. However, the increase of the apparent viscosity in the concentration polarization layer hinders diffusion of particles back into the bulk and results in a small reduction in permeate flux. Depending on the number and type of particles present in the contaminated water, the concentration polarization will either reach a quasi-steady state or particles will begin to deposit onto the membrane. In the later case, a cake layer eventually forms on the membrane, significantly reducing the permeate flux. Contradictive theories suggest that the cake layer is either a porous solid or a very viscous (yield stress) fluid. New and refined models that shed light on these theories are presented.

A bench-top educational system, the Adaptive Water Treatment for Education and Research (WaTER) Laboratory, has been developed as part of a year-long capstone design project. The Adaptive WaTER Lab teaches students about the effectiveness of various water purification techniques. Stackable housings employ six different filtration and purification methods including: sediment filtration, carbon filtration, chemical disinfection, reverse osmosis, forward osmosis, and ultraviolet light disinfection. Filtration pressure is supplied by a hand or foot pump, and two rechargeable batteries are required for the UV sterilization unit. The advantages and limitations of each technique are investigated, with learning performance criteria measured by knowledge of: material costs, contaminant removal or neutralization capabilities (from large sediment to bacteria and viruses to chemicals), robustness and longevity, and power requirements and efficiencies. Finally, suitable combinations of treatment techniques are studied for specific contamination issues, with the ultimate goal of producing potable water. The importance of sustainable water use is also discussed. Background information and suggested experiments are introduced through accompanying educational packets. This system has had a successful impact on undergraduate education. The metrics of success include a published journal article, an awarded EPA P3 educational grant and a pending patent for the undergraduates involved in the development of the Lab. Other undergraduates are currently involved in a design for manufacturability study. Finally, the Lab has served as a demonstration tool in a new interdisciplinary engineering course “Integrated Approaches to Sustainable Development.” The Adaptive WaTER Lab has also been used in hands-on outreach to over 300 underrepresented K-12 students in the Houston area. Two high school students borrowed the original prototype of the Lab to use in an Earth Day demonstration, and one student recently worked on an individual project using the Lab. Because the Lab is portable and requires only human and solar power (to recharge the batteries via a solar backpack), it is also ideal for educational efforts in developing nations. Labs are currently being produced for outreach and donation via three international projects to install water purification systems and/or educational Labs in schools and clinics in Mexico, Lesotho and Swaziland, in collaboration with the Beyond Traditional Borders and Rice 360 health initiatives.