particle

Articles containing copper nanoparticles and methods for production and use thereof

Articles containing a matrix material and plurality of copper nanoparticles in the matrix material that have been at least partially fused together are described. The copper nanoparticles are less than about 20 nm in size. Copper nanoparticles of this size become fused together at temperatures and pressures that are much lower than that of bulk copper. In general, the fusion temperatures decrease with increasing applied pressure and lowering of the size of the copper nanoparticles. The size of the copper nanoparticles can be varied by adjusting reaction conditions including, for example, surfactant systems, addition rates, and temperatures. Copper nanoparticles that have been at least partially fused together can form a thermally conductive percolation pathway in the matrix material.




particle

Method of generating hydrogen from the reaction of stabilized aluminum nanoparticles with water and method of forming stabilized aluminum nanoparticles

A method of generating hydrogen gas from the reaction of stabilized aluminum nanoparticles with water is provided. The stabilized aluminum nanoparticles are synthesized from decomposition of an alane precursor in the presence of a catalyst and an organic passivation agent, and exhibit stability in air and solvents but are reactive with water. The reaction of the aluminum nanoparticles with water produces a hydrogen yield of at least 85%.




particle

Highly aromatic compounds and polymers as precursors to carbon nanotube and metal nanoparticle compositions in shaped solids

A method of making metal nanoparticles and carbon nanotubes is disclosed. A mixture of a transition metal compound and an aromatic polymer, a precursor of an aromatic polymer, or an aromatic monomer is heated to form a metal nanoparticle composition, optionally containing carbon nanotubes.




particle

Composition for the synthesis of bimetallic nanoparticles in an ionic liquid and associated method

The invention relates to a composition for synthesizing bimetallic nanoparticles, wherein the composition contains a first organometallic precursor and a second organometallic precursor having different decomposition rates and contained within an ionic liquid solution. The invention also relates to a method for synthesizing bimetallic nanoparticles, in which the composition is transformed under a hydrogen gas pressure between 0.1 and 10 MPa at a temperature between 0 and 150° C. until a suspension of bimetallic nanoparticles is obtained. The resulting nanoparticles are useful in diverse fields including the fields of catalysis and microelectronics.




particle

Methods of producing nanoparticle reinforced metal matrix nanocomposites from master nanocomposites

Methods of forming metal matrix nanocomposites are provided. The methods include the steps of introducing a master metal matrix nanocomposite into a molten metal at a temperature above the melting temperature of the master metal matrix nanocomposite, allowing at least a portion of the master metal matrix nanocomposite to mix with the molten metal and, then, solidifying the molten metal to provide a second metal matrix nanocomposite.




particle

Novel method for preparing pH dependent Ultra Small Polymeric Nanoparticles for topical and/or Transdermal delivery

The invention provides a new method for preparing ultra-small polymeric-lipidic delivery nanoparticles (USDNs) that were synthesized by a nanoprecipitation method followed by a layer-by-layer nanodeposition. The USDNs particle size can be controlled between 5-25 mn and provides loading capacities of 22.12% to 72.08%. Moreover, the USDNs platform provides pH controlled drug release, within a terminal release ratio of 68% at pH 5.0 and almost no release to pH of 7.5. Furthermore, based on their small sizes (5-25 nm) and unique composition, the USDNs penetrates the skin strata efficiently, release the payload at the target site as topical or transdermal treatment of a variety of skin disorders. Additionally the USDNs system can be used to treat and diagnoses other crucial diseases (Cancer, Alzheimer, etc) can be combined with various micro-needles or needles free array technologies for special application.




particle

Fertilizer composition incorporating fibrous material for enhanced particle integrity

Fertilizer granules and methods of producing fertilizer granules. The fertilizer granules are formed from a fertilizer composition, such as a phosphate fertilizer, includes a fibrous material for the purpose of increasing the granule strength preventing or reducing attrition or dusting formation during storage, transport, and/or handling of the fertilizer. Dust formation can be reduced fifty percent or more. The base fertilizer composition can include a phosphate fertilizer, such as monoammonium phosphate (MAP) or diammonium phosphate (DAP), and optionally one or more micronutrients or secondary nutrients, such as elemental sulfur. The fibrous material is pulp or paper sludge, for example.




particle

Compositions of substantially spherical particles and methods of making thereof

An improved composition comprising substantial spherical UFP particles and an active agent, such as NBPT, and optionally other components is used as an additive for liquid and solid fertilizers, typically containing urea. Methods of making the compositions and their use are also disclosed.




particle

Particle analysis in an acoustic cytometer

The present invention is a method and apparatus for acoustically manipulating one or more particles.




particle

Method for producing toner for developing electrostatic image and apparatus for producing resin particles

A method for producing resin particles, including ejecting a liquid containing at least a resin in the form of droplets from a droplet ejecting unit having a plurality of holes provided in a part of a flow channel for feeding the liquid containing at least a resin, and drying and solidifying the ejected droplets so as to obtain the resin particles, while the ejected droplets are transported by a primary transport air flow flowing in the direction in which the droplets are ejected, wherein the ejected droplets are further transported by a secondary transport air flow which transports the ejected droplets in a different direction from a direction in which the primary transport air flow flows, and wherein a smaller angle of angles formed between a velocity vector of the primary transport air flow and a velocity vector of the secondary transport air flow is less than 120 degrees.




particle

Recrystallization method of fine spherical RDX particle

The present invention relates to a method for recrystallizing fine spherical cyclotrimethylenetrinitramine (Research Department Explosive, hereinafter, referred to as “RDX”) particles, and the method for recrystallizing fine spherical RDX particles according to the present invention may include (a) introducing a powder material containing RDX into a container, (b) introducing a dimethylether compressed gas into the container and dissolving the RDX to form a RDX solution, (c) releasing and decompressing the RDX solution into atmospheric pressure to form crystallized RDX particles, and (d) separating and collecting the RDX particles.




particle

Particles of an explosive of low sensitivity to shock and associated treatment process

The invention relates to the field of explosives, and more particularly relates to particles of an explosive, wherein they are in crystalline form, have a rounded shape and a majority of them contain no internal defect. Particles of an explosive in crystalline form include a volume fraction of closed pores of less than or equal to 0.05%. A method for preparing explosive particles includes preparing crystalline particles, a majority of which are without an internal defect; and rounding the crystalline particles.




particle

Delivery particle

The present application relates to encapsulated benefit agents, compositions comprising such encapsulated benefit agents and processes for making and using compositions comprising such encapsulated benefit agents that do not require or require a reduced amount of scavenger materials. Such encapsulated benefit agents, compositions comprising such encapsulated benefit agents are processed such that no or lower levels of scavenger materials are required.




particle

Acoustical treatment of polymeric fibers and small particles and apparatus therefor

Systems and methods for treating small elongated fibrous and particles of certain materials, e.g., PTFE materials in a suspension are presented. In some instances, high-intensity ultrasound (or acoustical energy) is applied to a sample of the material, through a fluid coupling medium or suspension, to achieve a material transformation in the sample. In various embodiments, fibrillation of particles of PTFE or similar materials is accomplished, or the formation of extended structures of these materials is caused or enhanced. Also, the ability to separate long fiber samples by ultrasonic or acoustic cavitation action is provided.




particle

Methods of fabricating polycrystalline diamond products using a selected amount of graphite particles

Embodiments of the invention relate to polycrystalline diamond (“PCD”) fabricated by sintering a mixture including diamond particles and a selected amount of graphite particles, polycrystalline diamond compacts (“PDCs”) having a PCD table comprising such PCD, and methods of fabricating such PCD and PDCs. In an embodiment, a method includes providing a mixture including graphite particles present in an amount of about 0.1 weight percent (“wt %”) to about 20 wt % and diamond particles. The method further includes subjecting the mixture to a high-pressure/high-temperature process sufficient to form PCD.




particle

Abrasive articles including abrasive particles of silicon nitride

An abrasive article includes a body having abrasive particles contained within a bond material. The abrasive particles can include a majority content of silicon nitride and a minority content of sintering material including at least two rare-earth oxide materials. In an embodiment, the rare-earth oxide materials can include Nd2O3 and Y2O3. In a particular embodiment, the abrasive particles comprise a content (wt %) of Nd2O3 that is greater than a content of Y2O3 (wt %).




particle

Methods for orienting superabrasive particles on a surface and associated tools

Methods of making a superabrasive tool precursor are disclosed, along with such precursors and associated tools. Particularly, methods are disclosed for orienting superabrasive particles in a viscous binding material in order to provide tools based thereupon and having desired performance characteristics.




particle

Abrasive particles having particular shapes and methods of forming such particles

An abrasive article includes a shaped abrasive particle including a body having a first height (h1) at a first end of the body defining a corner between an upper surface, a first side surface, and a second side surface, and a second height (h2) at a second end of the body opposite the first end defining an edge between the upper surface and a third side surface, wherein the average difference in height between the first height and the second height is at least about 50 microns. The body also includes a bottom surface defining a bottom area (Ab) and a cross-sectional midpoint area (Am) defining an area of a plane perpendicular to the bottom area and extending through a midpoint of the particle, the body has an area ratio of bottom area to midpoint area (Ab/Am) of not greater than about 6.




particle

Polishing composition and method utilizing abrasive particles treated with an aminosilane

The inventive method comprises chemically-mechanically polishing a substrate with an inventive polishing composition comprising a liquid carrier and abrasive particles that have been treated with a compound.




particle

Abrasive articles including abrasive particles bonded to an elongated body, and methods of forming thereof

An abrasive article includes an elongated body, a bonding layer including a metal overlying a surface of the elongated body, and a coating layer including a polymer material overlying the boding layer. The abrasive article further includes abrasive grains contained within the bonding layer and coating layer, and wherein the bonding layer comprises an average thickness (tbl) at least about 40% of the average grit size of the abrasive grains.




particle

Shaped abrasive particles and method of making

A method of making shaped abrasive particles including forming an abrasive flake comprising a plurality of precursor shaped abrasive particles and a frangible support joining the precursor shaped abrasive particles together; transporting the abrasive flake through a rotary kiln to sinter the abrasive flake; and breaking the sintered abrasive flake into individual shaped abrasive particles. The method is useful to make small shaped abrasive particles having insufficient mass to be efficiently individually sintered in a rotary kiln without joining two or more of the shaped abrasive particles together.




particle

AMINO-CONTAINING SILICA PARTICLE, COMPOSITION FOR FORMING POLYIMIDE AEROGEL, POLYIMIDE AEROGEL AND METHOD OF FABRICATING THE SAME, POLYIMIDE AEROGEL-CONTAINING COMPOSITE MATERIAL

An amino-containing silica particle is provided. The amino-containing silica particle is obtained by hydrolysis-condensation reaction of an alkoxy silane represented by formula (I), an alkoxy silane represented by formula (II) and a catalyst: Si(OR1)4 formula (I) (NH2—Y)m—Si(OR2)4-m formula (II) wherein in formula (I), R1 is a C1-C10 alkyl group, and in formula (II), Y is a C1-C10 alkyl group or a C2-C10 alkenyl group, R2 is a C1-C10 alkyl group, and m is an integer of 1 to 3.




particle

METHOD FOR MANUFACTURING MAGNETIC PARTICLES, MAGNETIC PARTICLES, AND MAGNETIC BODY

Provided is a method for manufacturing magnetic particles, in which an oxidation treatment, a reduction treatment, and a nitriding treatment are performed in that order on raw material particles with a core-shell structure in which a silicon oxide layer is formed on the surfaces of iron microparticles, thereby nitriding the iron microparticles while maintaining the core-shell structure. Due to this configuration, granular magnetic particles with a core-shell structure in which a silicon oxide layer is formed on the surfaces of iron nitride microparticles can be obtained.




particle

Methods of producing a titanium dioxide pigment and improving the processability of titanium dioxide pigment particles

A method of producing a titanium dioxide pigment is provided. Also provided is a method of improving the processability of titanium dioxide particles without adversely affecting the rheological properties of the titanium dioxide particles.




particle

Method of making titanium dioxide in the shape of columnar particles

Titanium dioxide which includes particles having a large major-axis length in a large proportion and comprises columnar particles having a satisfactory particle size distribution. A titanium compound, an alkali metal compound, and an oxyphosphorus compound are heated/fired in the presence of titanium dioxide nucleus crystals having an aspect ratio of 2 or higher to grow the titanium dioxide nucleus crystals. Subsequently, a titanium compound, an alkali metal compound, and an oxyphosphorus compound are further added and heated/fired in the presence of the grown titanium dioxide nucleus crystals. Thus, titanium dioxide is produced which comprises columnar particles having a weight-average major-axis length of 7.0-15.0 μm and in which particles having a major-axis length of 10 μm or longer account for 15 wt. % or more of all the particles.




particle

Fine crystal particle production method

An object of the present invention is to provide a fine crystal particle production method and device that are excellent in mixing efficiency. This object is achieved by a method for producing fine crystal particles, comprising: a swirl flow producing step at which a swirl flow of liquid a comprising reactant A is supplied into a cylinder having a circumferential surface partially or wholly composed of a porous membrane; and a reaction step at which liquid b comprising reactant B which is reactive with the reactant A is supplied through the porous membrane to the swirl flow to effect mixing, whereby the reactants A and B are reacted to precipitate fine crystal particles.




particle

AEROSOL PARTICLE MASS SENSOR AND SENSING METHOD

A mass sensor is provided for measuring a particle mass within an aerosol. The duration of a sensing cycle is set such that a pre-set change in mass resulting from particles deposited is caused. In the absence of cleaning, the lifetime of the sensor is dependent on the total mass deposited. As a result, the lifetime is made essentially constant by this approach, because each sensing operation is made to give rise to a constant amount of deposited particle mass. This means the lifetime can be predicted more accurately.




particle

PROCESS FOR CONTROLLING, UNDER VOID, A JET OF PARTICLES WITH AN AERODYNAMIC LENS AND ASSOCIATED AERODYNAMIC LENS

The invention relates to a method for controlling the divergence of a jet of particles in vacuo with an aerodynamic lens, the aerodynamic lens including at least one chamber; a diaphragm, a so-called inlet diaphragm, intended to form an inlet of the aerodynamic lens for a jet of particles, the inlet diaphragm having a given diameter (d1); and another diaphragm, a so-called outlet diaphragm, intended to form an outlet of the aerodynamic lens for this jet of particles; the method including: a step for generating the jet of particles from the inlet to the outlet, in vacuo, of the aerodynamic lens; and a step for adjusting the diameter (ds) of the outlet diaphragm for controlling the divergence of the jet of particles.




particle

COPPER NANOPARTICLES FOR DEGRADATION OF POLLUTANTS

The present invention is directed to a degradation composition, methods and kits for degrading organic pollutants comprising reduced copper based nanoparticles-polymer complex (Cu-NPs) and an oxidant.




particle

METHOD FOR REMOVING GLYPHOSATE FROM A SOLUTION USING FUNCTIONALIZED POLYMERIC NANOPARTICLES

A method for removing glyphosate from a solution by contacting the solution with a polymeric particle including a moiety selected from the group consisting of ammonium, amine and combinations thereof, wherein the moiety is positively charged in the solution.




particle

Biological composite material loaded with magnetic nanoparticles with core-shell structure, the preparation therefore and the application

A preparation method of Bacillus subtilis biological composite material loaded with Fe3O4 magnetic nanoparticles with core-shell structure includes the following steps: 1) preparation of Fe3O4 nanoparticles, 2) preparation of Fe3O4@mSiO2 nanoparticles, 3) preparation of Fe3O4@mSiO2@MANHE nanoparticles; and 4) preparation of Bacillus subtilis@Fe3O4@mSiO2@MANHE composite.




particle

Methods and Apparatus for Creating Particle Derivatives of HDL with Reduced Lipid Content

The present invention is directed to systems, apparatus and methods for creating derivatives of at least one form of HDL without substantially affecting LDL. These derivatives of HDL are particles with reduced lipid content, particularly reduced cholesterol content. These particles have the capacity to bind cholesterol and are administered to a patient to enhance cellular cholesterol efflux and reduce cholesterol levels in cells, tissues, organs, and blood vessels. The present method is useful for treating atherogenic vascular disease and may be combined with other therapies such as statins, inhibitors of cholesterol absorption, niacin, anti-inflammatories, exercise and dietary restriction.




particle

Liquid to Liquid Biological Particle Concentrator with Disposable Fluid Path

Highly efficient and rapid filtration-based concentration devices, systems and methods are disclosed with sample fluidic lines and a filter packaged in a disposable tip which concentrate biological particles that are suspended in liquid from a dilute feed suspension. A sample concentrate or retentate suspension is retained while eliminating the separated fluid in a separate flow stream. The concentrate is then dispensed from the disposable tip in a set volume of elution fluid. Suspended biological particles include such materials as proteins/toxins, viruses, DNA, and/or bacteria in the size range of approximately 0.001 micron to 20 microns diameter. Concentration of these particles is advantageous for detection of target particles in a dilute suspension, because concentrating them into a small volume makes them easier to detect. All conduits by which the disposable tip attaches to the instrument are combined into a single connection point on the upper end of the tip.




particle

DIGITAL CONTROL OF ON-CHIP MAGNETIC PARTICLE ASSAY

An assay system and method for use in the field of chemical testing is disclosed. The assay system can be used for filtering whole blood for testing on an integrated circuit containing digital control functionality.




particle

Magnetic particle embedded flex or printed flex for magnetic tray or electro-magnetic carrier

In accordance with disclosed embodiments, there are provided methods, systems, and apparatuses for implementing a magnetic particle embedded flexible substrate, a printed flexible substrate for a magnetic tray, or an electro-magnetic carrier for magnetized or ferromagnetic flexible substrates. For instance, in accordance with one embodiment, there are means disclosed for fabricating a flexible substrate having one or more electrical interconnects to couple with leads of an electrical device; integrating magnetic particles or ferromagnetic particles into the flexible substrate; supporting the flexible substrate with a carrier plate during one or more manufacturing processes for the flexible substrate, in which the flexible substrate is held flat against the carrier plate by an attractive magnetic force between the magnetic particles or ferromagnetic particles integrated with the flexible substrate and a complementary magnetic attraction of the carrier plate; and removing the flexible substrate from the carrier plate subsequent to completion of the one or more manufacturing processes for the flexible substrate. Other related embodiments are disclosed.




particle

Micah Frank releases Tape Pieces Vol. 2 + Strata particle tape loop device (FREE)

Micah Frank has announced the release of Tape Pieces Vol. 2, a new installment in the series of collaborations between Micah Frank and Chris Child (Kodomo). The EP contains four compositions that Chris and Micah built from field recordings, cassette tapes and synthesizers. While Tape Pieces Volume One focused on the layering and cascading of […]

The post Micah Frank releases Tape Pieces Vol. 2 + Strata particle tape loop device (FREE) appeared first on rekkerd.org.




particle

Innovate UK £2.25m funds particle beams in 3D printing innovation

University of Huddersfield scientists have teamed with the Huddersfield company Reliance Precision for two successive 3D printing projects that have earned £2.25 million funding from Innovate UK.



  • 3D Printing Applications

particle

Particle Physics Turns to Quantum Computing for Solutions to Tomorrow's Big-Data Problems

Giant-scale physics experiments are increasingly reliant on big data and complex algorithms fed into powerful computers, and managing this multiplying mass of data presents its own unique challenges. To better prepare for this data deluge posed by next-generation upgrades and new experiments, physicists are turning to the fledgling field of quantum computing.




particle

FDA approves ventilator designed by particle physics community

Led by Princeton’s Cristian Galbiati, a massive international team worked to design, test and finalize the Mechanical Ventilator Milano (MVM), a low-cost ventilator designed to ease device shortages caused by COVID-19.




particle

The ins and outs of lipid rafts: functions in intracellular cholesterol homeostasis, microparticles, and cell membranes [Thematic Reviews]

Cellular membranes are not homogenous mixtures of proteins; rather, they are segregated into microdomains on the basis of preferential association between specific lipids and proteins. These microdomains, called lipid rafts, are well known for their role in receptor signaling on the plasma membrane (PM) and are essential to such cellular functions as signal transduction and spatial organization of the PM. A number of disease states, including atherosclerosis and other cardiovascular disorders, may be caused by dysfunctional maintenance of lipid rafts. Lipid rafts do not occur only in the PM but also have been found in intracellular membranes and extracellular vesicles (EVs). Here, we focus on discussing newly discovered functions of lipid rafts and microdomains in intracellular membranes, including lipid and protein trafficking from the ER, Golgi bodies, and endosomes to the PM, and we examine lipid raft involvement in the production and composition of EVs. Because lipid rafts are small and transient, visualization remains challenging. Future work with advanced techniques will continue to expand our knowledge about the roles of lipid rafts in cellular functioning.




particle

Composition-function analysis of HDL subpopulations: influence of lipid composition on particle functionality [Research Articles]

The composition-function relationship of HDL particles and its effects on the mechanisms driving coronary heart disease (CHD) is poorly understood. We tested the hypothesis that the functionality of HDL particles is significantly influenced by their lipid composition. Using a novel 3D-separation method, we isolated five different-sized HDL subpopulations from CHD patients who had low preβ-1 functionality (low-F) (ABCA1-dependent cholesterol-efflux normalized for preβ-1 concentration) and controls who had either low-F or high preβ-1 functionality (high-F). Molecular numbers of apoA-I, apoA-II, and eight major lipid classes were determined in each subpopulation by LC-MS. The average number of lipid molecules decreased from 422 in the large spherical α-1 particles to 57 in the small discoid preβ-1 particles. With decreasing particle size, the relative concentration of free cholesterol (FC) decreased in α-mobility but not in preβ-1 particles. Preβ-1 particles contained more lipids than predicted; 30% of which were neutral lipids (cholesteryl ester and triglyceride), indicating that these particles were mainly remodeled from larger particles not newly synthesized. There were significant correlations between HDL-particle functionality and the concentrations of several lipids. Unexpectedly, the phospholipid:FC ratio was significantly correlated with large-HDL-particle functionality but not with preβ-1 functionality. There was significant positive correlation between particle functionality and total lipids in high-F controls, indicating that the lipid-binding capacity of apoA-I plays a major role in the cholesterol efflux capacity of HDL particles. Functionality and lipid composition of HDL particles are significantly correlated and probably both are influenced by the lipid-binding capacity of apoA-I.




particle

The ins and outs of lipid rafts: functions in intracellular cholesterol homeostasis, microparticles, and cell membranes [Thematic Reviews]

Cellular membranes are not homogenous mixtures of proteins; rather, they are segregated into microdomains on the basis of preferential association between specific lipids and proteins. These microdomains, called lipid rafts, are well known for their role in receptor signaling on the plasma membrane (PM) and are essential to such cellular functions as signal transduction and spatial organization of the PM. A number of disease states, including atherosclerosis and other cardiovascular disorders, may be caused by dysfunctional maintenance of lipid rafts. Lipid rafts do not occur only in the PM but also have been found in intracellular membranes and extracellular vesicles (EVs). Here, we focus on discussing newly discovered functions of lipid rafts and microdomains in intracellular membranes, including lipid and protein trafficking from the ER, Golgi bodies, and endosomes to the PM, and we examine lipid raft involvement in the production and composition of EVs. Because lipid rafts are small and transient, visualization remains challenging. Future work with advanced techniques will continue to expand our knowledge about the roles of lipid rafts in cellular functioning.




particle

UCLA dental school researchers create nanoparticle that could improve bone defect treatment

A team of researchers at the University of California, Los Angeles School of Dentistry has developed a nanoparticle that could improve treatment for bone defects.




particle

Coldest material in the cosmos could help scientists find dark matter particles

Researchers suggest the coldest material in the universe could reveal the presence of dark matter particles.




particle

Asymptotic genealogies of interacting particle systems with an application to sequential Monte Carlo

Jere Koskela, Paul A. Jenkins, Adam M. Johansen, Dario Spanò.

Source: The Annals of Statistics, Volume 48, Number 1, 560--583.

Abstract:
We study weighted particle systems in which new generations are resampled from current particles with probabilities proportional to their weights. This covers a broad class of sequential Monte Carlo (SMC) methods, widely-used in applied statistics and cognate disciplines. We consider the genealogical tree embedded into such particle systems, and identify conditions, as well as an appropriate time-scaling, under which they converge to the Kingman $n$-coalescent in the infinite system size limit in the sense of finite-dimensional distributions. Thus, the tractable $n$-coalescent can be used to predict the shape and size of SMC genealogies, as we illustrate by characterising the limiting mean and variance of the tree height. SMC genealogies are known to be connected to algorithm performance, so that our results are likely to have applications in the design of new methods as well. Our conditions for convergence are strong, but we show by simulation that they do not appear to be necessary.




particle

How to Boost Visuals Using Particles in Unreal Engine*

  Particle parameters are a powerful system built into the Unreal Engine* that allows the customization of particle systems outside of Unreal Engine 4's Cascade particle editor. This tutorial create...




particle

Strange particles found in Antarctica cannot be explained by physics

A NASA science balloon picked up two high-energy particles and a new analysis reveals that they can't be explained by the standard model of particle physics




particle

The ins and outs of lipid rafts: functions in intracellular cholesterol homeostasis, microparticles, and cell membranes [Thematic Reviews]

Cellular membranes are not homogenous mixtures of proteins; rather, they are segregated into microdomains on the basis of preferential association between specific lipids and proteins. These microdomains, called lipid rafts, are well known for their role in receptor signaling on the plasma membrane (PM) and are essential to such cellular functions as signal transduction and spatial organization of the PM. A number of disease states, including atherosclerosis and other cardiovascular disorders, may be caused by dysfunctional maintenance of lipid rafts. Lipid rafts do not occur only in the PM but also have been found in intracellular membranes and extracellular vesicles (EVs). Here, we focus on discussing newly discovered functions of lipid rafts and microdomains in intracellular membranes, including lipid and protein trafficking from the ER, Golgi bodies, and endosomes to the PM, and we examine lipid raft involvement in the production and composition of EVs. Because lipid rafts are small and transient, visualization remains challenging. Future work with advanced techniques will continue to expand our knowledge about the roles of lipid rafts in cellular functioning.




particle

Snake Deltavirus Utilizes Envelope Proteins of Different Viruses To Generate Infectious Particles

ABSTRACT

Satellite viruses, most commonly found in plants, rely on helper viruses to complete their replication cycle. The only known example of a human satellite virus is the hepatitis D virus (HDV), and it is generally thought to require hepatitis B virus (HBV) to form infectious particles. Until 2018, HDV was the sole representative of the genus Deltavirus and was thought to have evolved in humans, the only known HDV host. The subsequent identification of HDV-like agents in birds, snakes, fish, amphibians, and invertebrates indicated that the evolutionary history of deltaviruses is likely much longer than previously hypothesized. Interestingly, none of the HDV-like agents were found in coinfection with an HBV-like agent, suggesting that these viruses use different helper virus(es). Here we show, using snake deltavirus (SDeV), that HBV and hepadnaviruses represent only one example of helper viruses for deltaviruses. We cloned the SDeV genome into a mammalian expression plasmid, and by transfection could initiate SDeV replication in cultured snake and mammalian cell lines. By superinfecting persistently SDeV-infected cells with reptarenaviruses and hartmaniviruses, or by transfecting their surface proteins, we could induce production of infectious SDeV particles. Our findings indicate that deltaviruses can likely use a multitude of helper viruses or even viral glycoproteins to form infectious particles. This suggests that persistent infections, such as those caused by arenaviruses and orthohantaviruses used in this study, and recurrent infections would be beneficial for the spread of deltaviruses. It seems plausible that further human or animal disease associations with deltavirus infections will be identified in the future.

IMPORTANCE Deltaviruses need a coinfecting enveloped virus to produce infectious particles necessary for transmission to a new host. Hepatitis D virus (HDV), the only known deltavirus until 2018, has been found only in humans, and its coinfection with hepatitis B virus (HBV) is linked with fulminant hepatitis. The recent discovery of deltaviruses without a coinfecting HBV-like agent in several different taxa suggested that deltaviruses could employ coinfection by other enveloped viruses to complete their life cycle. In this report, we show that snake deltavirus (SDeV) efficiently utilizes coinfecting reptarena- and hartmaniviruses to form infectious particles. Furthermore, we demonstrate that cells expressing the envelope proteins of arenaviruses and orthohantaviruses produce infectious SDeV particles. As the envelope proteins are responsible for binding and infecting new host cells, our findings indicate that deltaviruses are likely not restricted in their tissue tropism, implying that they could be linked to animal or human diseases other than hepatitis.




particle

Induction of Protective Antiplague Immune Responses by Self-Adjuvanting Bionanoparticles Derived from Engineered Yersinia pestis [Microbial Immunity and Vaccines]

A Yersinia pestis mutant synthesizing an adjuvant form of lipid A (monophosphoryl lipid A, MPLA) displayed increased biogenesis of bacterial outer membrane vesicles (OMVs). To enhance the immunogenicity of the OMVs, we constructed an Asd-based balanced-lethal host-vector system that oversynthesized the LcrV antigen of Y. pestis, raised the amounts of LcrV enclosed in OMVs by the type II secretion system, and eliminated harmful factors like plasminogen activator (Pla) and murine toxin from the OMVs. Vaccination with OMVs containing MPLA and increased amounts of LcrV with diminished toxicity afforded complete protection in mice against subcutaneous challenge with 8 x 105 CFU (80,000 50% lethal dose [LD50]) and intranasal challenge with 5 x 103 CFU (50 LD50) of virulent Y. pestis. This protection was significantly superior to that resulting from vaccination with LcrV/alhydrogel or rF1-V/alhydrogel. At week 4 postimmunization, the OMV-immunized mice showed more robust titers of antibodies against LcrV, Y. pestis whole-cell lysate (YPL), and F1 antigen and more balanced IgG1:IgG2a/IgG2b-derived Th1 and Th2 responses than LcrV-immunized mice. Moreover, potent adaptive and innate immune responses were stimulated in the OMV-immunized mice. Our findings demonstrate that self-adjuvanting Y. pestis OMVs provide a novel plague vaccine candidate and that the rational design of OMVs could serve as a robust approach for vaccine development.