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1

Particles causing lung disease.  

PubMed Central

The lung has a limited number of patterns of reaction to inhaled particles. The disease observed depends upon the location: conducting airways, terminal bronchioles and alveoli, and upon the nature of inflammation induced: acute, subacute or chronic. Many different agents cause narrowing of conducting airways (asthma) and some of these cause permanent distortion or obliteration of airways as well. Terminal bronchioles appear to be particularly susceptible to particles which cause goblet cell metaplasia, mucous plugging and ultimately peribronchiolar fibrosis. Cancer is the last outcome at the bronchial level and appears to depend upon continuous exposure to or retention of an agent in the airway and failure of the affected cells to be exfoliated which may be due to squamous metaplasia. Alveoli are populated by endothelial cells, Type I or pavement epithelial cells and metabolically active cuboidal Type II cells that produce the lungs specific surfactant, dipalmytol lecithin. Disturbances of surfactant lead to edema in distal lung while laryngeal edema due to anaphylaxis or fumes may produce asphyxia. Physical retention of indigestible particles or retention by immune memory responses may provoke hyaline membranes, stimulate alveolar lipoproteinosis and finally fibrosis. This later exuberant deposition of connective tissue has been best studied in the occupational pneumoconioses especially silicosis and asbestosis. In contrast emphysema a catabolic response, appears frequently to result from leakage or release of lysosomal proteases into the lung during processing of cigarette smoke particles. The insidious and probably most important human lung disease due to particles is bronchiolar obstruction and obliteration, producing progressive impairment of air flow. The responsible particle is the complex combination of poorly digestive lipids and complex carbohydrates with active chemicals which we call cigarette smoke. More research is needed to perfect, correct and quantify our preliminary picture of the pathogenesis of lung disease by particles, but a useful start has been made. Images FIGURE 1.

Kilburn, K H

1984-01-01

2

Unhealthy diet and ultrafine carbon black particles induce senescence and disease associated phenotypic changes.  

PubMed

Diet and pollution are environmental factors known to compromise "healthy aging" of the cardiovascular and respiratory systems. The molecular consequences of this permanent burden in these cells are still unknown. Therefore, this study investigates the impact of unhealthy diet on aging-related signaling pathways of human, primary cardiovascular cells and of airborne particles on lung epithelial and human endothelial cells. Nutrition health reports have shown that the diet in industrialized countries contains more than 100mg/dl low density lipoprotein (LDL) and a high fraction of added sugars, especially fructose. Several studies demonstrated that ultrafine particles can enter the circulation and thus may interact with endothelial cells directly. Both, dietary compounds and pollution derived particles, have been shown to increase the risk for cardiovascular diseases. To simulate an unhealthy diet, we supplemented cell culture media of human primary endothelial cells, smooth muscle cells and cardiomyocytes with LDL and replaced 1/3 of glucose with fructose. We observed hypertrophy in cardiomyocytes, enhanced proliferation in smooth muscle cells and increased senescence, loss of endothelial nitric oxide synthase and increased nuclear FoxO3A in endothelial cells. With respect to pollution we have used ultrafine carbon black particles (ufCB), one of the major constituents of industrial and exhaust emissions, in concentrations our lungs and vessels are constantly exposed to. These concentrations of ufCB increased reactive oxygen species in lung epithelial and vascular endothelial cells and reduced the S-NO content, a marker for NO-bioavailability, in endothelial cells. NO increases activation of Telomerase Reverse Transcriptase (TERT), an enzyme essential for telomere maintenance. TERT is required for proper endothelial cell function and is inactivated by Src kinase under conditions of oxidative stress. ufCB significantly increased Src kinase activation and reduced Telomerase activity in endothelial and lung epithelial cells. As a consequence, ufCB increased senescence of endothelial cells. To investigate whether ufCB show also effects in vivo, we instilled ufCB in concentrations not inducing inflammation into mice. Indeed, eNOS expression was reduced in the abdominal aorta of animals treated with ufCB. Thus, a combination of fructose and LDL in the diet and ufCB, as a major constituent of air pollution, seem to accelerate respiratory and cardiovascular cellular changes, which may compromise "healthy aging" and can lead to cardiovascular and pulmonary diseases. PMID:22507566

Büchner, Nicole; Ale-Agha, Niloofar; Jakob, Sascha; Sydlik, Ulrich; Kunze, Kerstin; Unfried, Klaus; Altschmied, Joachim; Haendeler, Judith

2013-01-01

3

Venezuelan Equine Encephalitis Replicon Particles Can Induce Rapid Protection against Foot-and-Mouth Disease Virus  

PubMed Central

We have previously shown that delivery of the porcine type I interferon gene (poIFN-?/?) with a replication-defective human adenovirus vector (adenovirus 5 [Ad5]) can sterilely protect swine challenged with foot-and-mouth disease virus (FMDV) 1 day later. However, the need of relatively high doses of Ad5 limits the applicability of such a control strategy in the livestock industry. Venezuelan equine encephalitis virus (VEE) empty replicon particles (VRPs) can induce rapid protection of mice against either homologous or, in some cases, heterologous virus challenge. As an alternative approach to induce rapid protection against FMDV, we have examined the ability of VRPs containing either the gene for green fluorescent protein (VRP-GFP) or poIFN-? (VRP-poIFN-?) to block FMDV replication in vitro and in vivo. Pretreatment of swine or bovine cell lines with either VRP significantly inhibited subsequent infection with FMDV as early as 6 h after treatment and for at least 120 h posttreatment. Furthermore, mice pretreated with either 107 or 108 infectious units of VRP-GFP and challenged with a lethal dose of FMDV 24 h later were protected from death. Protection was induced as early as 6 h after treatment and lasted for at least 48 h and correlated with induction of an antiviral response and production of IFN-?. By 6 h after treatment several genes were upregulated, and the number of genes and the level of induction increased at 24 h. Finally, we demonstrated that the chemokine IP-10, which is induced by IFN-? and VRP-GFP, is directly involved in protection against FMDV.

Diaz-San Segundo, Fayna; Dias, Camila C. A.; Moraes, Mauro P.; Weiss, Marcelo; Perez-Martin, Eva; Owens, Gary; Custer, Max; Kamrud, Kurt; de los Santos, Teresa

2013-01-01

4

Total revision of the hip using allograft to correct particle disease induced osteolysis: A case study  

Microsoft Academic Search

Total hip replacement is considered to be a highly successful and routine surgery; however, the internal components produce particles through friction and wear in the device. These particles are identified as one of the main reasons for total hip revisions. The generated, biologically active, particles provoke the formation of osteolytic areas through the inhibition of bone formation and increased fluid

Drew W. Taylor; Jennifer E. Taylor; Igal Raizman; Allan E. Gross

5

Angular and fibrous particles in lung in relation to silica-induced diseases  

Microsoft Academic Search

Introduction: The lung concentration of angular and fibrous particles was measured in cases of lung fibrosis only, in cases of lung fibrosis\\u000a and lung cancer, and in cases of lung cancer only. These patients worked in different trades (mining, foundries, construction\\u000a and were not a homogeneous group of exposed workers. Material and methods: Particles, both angular and fibrous, were extracted

A. Dufresne; R. Bégin; C. Dion; J. Jagirdar; W. N. Rom; P. Loosereewanich; D. C. F. Muir; A. C. Ritchie; G. Perrault

1998-01-01

6

Particle therapy for noncancer diseases  

SciTech Connect

Radiation therapy using high-energy charged particles is generally acknowledged as a powerful new technique in cancer treatment. However, particle therapy in oncology is still controversial, specifically because it is unclear whether the putative clinical advantages justify the high additional costs. However, particle therapy can find important applications in the management of noncancer diseases, especially in radiosurgery. Extension to other diseases and targets (both cranial and extracranial) may widen the applications of the technique and decrease the cost/benefit ratio of the accelerator facilities. Future challenges in this field include the use of different particles and energies, motion management in particle body radiotherapy and extension to new targets currently treated by catheter ablation (atrial fibrillation and renal denervation) or stereotactic radiation therapy (trigeminal neuralgia, epilepsy, and macular degeneration). Particle body radiosurgery could be a future key application of accelerator-based particle therapy facilities in 10 years from today.

Bert, Christoph; Engenhart-Cabillic, Rita; Durante, Marco [GSI Helmholtzzentrum fuer Schwerionenforschung, Biophysics Department, Planckstrasse 1, 64291 Darmstadt (Germany); Philipps-University Marburg, Center for Radiology, Department of Radiation Therapy, Baldinger Strasse, 35043 Marburg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Biophysics Department, Planckstrasse 1, 64291 Darmstadt (Germany); Technische Universitaet Darmstadt, Institut fuer Festkoerperphysik, Hochschulstrasse 3, 64289 Darmstadt (Germany) and Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany)

2012-04-15

7

Particle accelerator for inducing contained particle collisions  

US Patent & Trademark Office Database

A particle accelerator for inducing contained particle collisions. The particle accelerator includes two hollow dees of electrically conductive material which are separated and electrically insulated from each other. The dees are located between the poles of a strong magnet which generates a magnetic field through top and bottom sides of the dees. In addition, the dees are connected to an oscillator for providing an alternating voltage between the dees. The dees are located within a chamber containing a gas and/or vapor provided at a measurable pressure. Ions are accelerated in essentially spiral paths within the dees, and follow paths which may be both concentric and non-concentric with the dees whereby collisions are produced between accelerated ions and gas or vapor atoms contained within the chamber, as well as between pairs of accelerated ions following different paths. The particle collisions within the chamber produces neutrons, generates energy, and performs other useful functions associated with the interaction of particles.

2002-08-27

8

Induced Annihilation of Particle-Antiparticle Pairs.  

National Technical Information Service (NTIS)

A theoretical estimation is developed for coherent amplification of gamma radiation by induced annihilation of particle-antiparticle pairs, such as electron-positron. This may lead to the development of a new class of laser systems. The induced annihilati...

S. Eliezer

1989-01-01

9

Drug-induced pulmonary disease  

MedlinePLUS

Acute episodes usually go away within 48 - 72 hours after the medication has been stopped. Chronic symptoms may take longer to improve. Some drug-induced lung diseases, such as pulmonary fibrosis, ...

10

The significance of nanoparticles in particle-induced pulmonary fibrosis  

PubMed Central

Exposure to airborne nanoparticles contributes to many chronic pulmonary diseases. Nanoparticles, classified as anthropogenic and natural particles, and fibers of diameters less than 100 nm, have unrestricted access to most areas of the lung due to their size. Size relates to the deposition efficiency of the particle, with particles in the nano-range having the highest efficiencies. The deposition of nanoparticles in the lung can lead to chronic inflammation, epithelial injury, and further to pulmonary fibrosis. Cases of particle-induced pulmonary fibrosis, namely pneumoconiosis, are mostly occupationally influenced, and continue to be documented around the world. The tremendous growth of nanotechnology, however, has spurred fears of increased rates of pulmonary diseases, especially fibrosis. The severity of toxicological consequences warrants further examination of the effects of nanoparticles in humans, possible treatments and increased regulatory measures.

Byrne, James D; Baugh, John A

2008-01-01

11

Drug Induced Interstitial Lung Disease  

PubMed Central

With an increasing number of therapeutic drugs, the list of drugs that is responsible for severe pulmonary disease also grows. Many drugs have been associated with pulmonary complications of various types, including interstitial inflammation and fibrosis, bronchospasm, pulmonary edema, and pleural effusions. Drug-induced interstitial lung disease (DILD) can be caused by chemotherapeutic agents, antibiotics, antiarrhythmic drugs, and immunosuppressive agents. There are no distinct physiologic, radiographic or pathologic patterns of DILD, and the diagnosis is usually made when a patient with interstitial lung disease (ILD) is exposed to a medication known to result in lung disease. Other causes of ILD must be excluded. Treatment is avoidance of further exposure and systemic corticosteroids in patients with progressive or disabling disease.

Schwaiblmair, Martin; Behr, Werner; Haeckel, Thomas; Markl, Bruno; Foerg, Wolfgang; Berghaus, Thomas

2012-01-01

12

Energetic Particle-induced Geodesic Acoustic Mode  

SciTech Connect

A new energetic particle-induced Geodesic Acoustic Mode (EGAM) is shown to exist. The mode frequency, mode structure, and mode destabilization are determined non-perturbatively by energetic particle kinetic effects. In particular the EGAM frequency is found to be substantially lower than the standard GAM frequency. The radial mode width is determined by the energetic particle drift orbit width and can be fairly large for high energetic particle pressure and large safety factor. These results are consistent with the recent experimental observation of the beam- driven n=0 mode in DIII-D. The new mode is important since it can degrade energetic particle confinement as shown in the DIII-D experiments. The new mode may also affect the thermal plasma confinement via its interaction with plasma micro-turbulence.

Fu, G.Y.

2008-09-12

13

Chromium-induced kidney disease  

SciTech Connect

Kidney disease is often cited as one of the adverse effects of chromium, yet chronic renal disease due to occupational or environmental exposure to chromium has not been reported. Occasional cases of acute tubular necrosis (ATN) following massive absorption of chromate have been described. Chromate-induced ATN has been extensively studied in experimental animals following parenteral administration of large doses of potassium chromate (hexavalent). The chromate is selectively accumulated in the convoluted proximal tubule where necrosis occurs. An adverse long-term effect of low-dose chromium exposure on the kidneys is suggested by reports of low molecular weight (LMW) proteinuria in chromium workers. Excessive urinary excretion of {beta}{sub 2}-microglobulin, a specific proximal tubule brush border protein, and retinol-binding protein has been reported among chrome palters and welders. However, LMW proteinuria occurs after a variety of physiologic stresses, is usually reversible, and cannot by itself be considered evidence of chromic renal disease. Chromate-induced ATN and LMW proteinuria in chromium workers, nevertheless, raise the possibility that low-level, long-term exposure may produce persistent renal injury. The absence of evidence of chromate-induced chromic renal disease cannot be interpreted as evidence of the absence of such injury.

Wedeen, R.P. (VA Medical Center, East Orange, NJ (United States)); Qian, Lifen (New Jersey Medical School, Newark (United States))

1991-05-01

14

Apoptosis induced by parasitic diseases  

PubMed Central

Fatalities caused by parasitic infections often occur as a result of tissue injury that results from a form of host-cell death known as apoptosis. However, instead of being pathogenic, parasite-induced apoptosis may facilitate host survival. Consequently, it is of utmost importance to decipher and understand the process and the role of apoptosis induced or controlled by parasites in humans. Despite this, few studies provide definitive knowledge of parasite-induced host-cell apoptosis. Here, the focus is on a consideration of host-cell apoptosis as either a pathogenic feature or as a factor enabling parasite survival and development. Cell death by apoptotic-like mechanisms could be described as a ride to death with a return ticket, as initiation of the pathway may be reversed, with the potential that it could be manipulated for therapeutic purposes. The management of host-cell apoptosis could thus be an adjunctive factor for parasitic disease treatment. Evidence that the apoptotic process could be reversed by anti-apoptotic drugs has recently been obtained, leading to the possibility of host-cell rescue after injury. An important issue will be to predict the beneficial or deleterious effects of controlling human cell death by apoptotic-like mechanisms during parasitic diseases.

2010-01-01

15

Cytokines and particle-induced inflammatory cell recruitment.  

PubMed Central

The inflammatory response is a key component of host defense. However, excessive or persistent inflammation can contribute to the pathogenesis of disease. Inflammation is regulated, in part, by cytokines, which are small, typically glycosylated proteins that interact with membrane receptors to regulate cellular processes such as proliferation, differentiation, and secretion. During the past 10 years studies in humans and experimental animals have demonstrated that a cytokine called tumor necrosis factor alpha (TNF-alpha) plays a key role in the initiation of inflammatory responses in the lung and other tissues, including inflammation resulting from inhalation of noxious particles. There is now compelling evidence that one of the pathways by which inhaled particles stimulate the recruitment and subsequent activation of inflammatory cells is through the activation of lung macrophages to release TNF-alpha. TNF-alpha then acts via paracrine and autocrine pathways to stimulate cells to release other cytokines known as chemokines, which are directly chemotactic to leukocytes and other cells that participate in inflammatory and wound healing responses. In addition to a TNF-alpha-mediated pathway, there is growing evidence that some particles such as quartz and crocidolite can directly activate lung epithelial cells to release chemokines such as macrophage inflammatory protein-2, cytokine-induced neutrophil chemoattractant, and interleukin-8. A direct stimulatory effect of particles on lung epithelium may represent an additional or alternate pathway by which inhaled particles may elicit inflammation in the lung. Recent studies have suggested that oxidative stress may be a component of the mechanism by which particles activate cytokine production in cells such as macrophages and epithelial cells. The contribution of oxidative stress to particle-induced cytokine gene expression appears to be mediated, at least in part, through activation of the transcription factor nuclear factor kappa B. Images Figure 4. A Figure 4. B Figure 5. Figure 6. A Figure 6. B

Driscoll, K E; Carter, J M; Hassenbein, D G; Howard, B

1997-01-01

16

Drug-induced pulmonary disease.  

PubMed

Drug-induced disease of any system or organ can be associated with high morbidity and mortality, and it is tremendously costly to the health care of our country. More than 100 medications are known to affect the lungs adversely, including the airways in the form of cough and asthma, the interstitium with interstitial pneumonitis and noncardiac pulmonary edema, and the pleura with pleural effusions. Patients commonly do not even know what medications they are taking, do not bring them to the physician's office for identification, and usually do not relate over-the-counter medications with any problems they have. They assume that all nonprescription drugs are safe. Patients also believe that if they are taking prescription medications at their discretion, meaning on an as-needed basis, then these medications are also not important. This situation stresses just how imperative it is for the physician to take an accurate drug history in all patients seen with unexplained medical situations. Cardiovascular drugs that most commonly produce a pulmonary abnormality are amiodarone, the angiotensin-converting enzyme inhibitors, and beta-blockers. Pulmonary complications will develop in 6% of patients taking amiodarone and 15% taking angiotensin-converting enzyme inhibitors, with the former associated with interstitial pneumonitis that can be fatal and the latter associated with an irritating cough that is not associated with any pathologic or physiologic sequelae of consequence. The beta-blockers can aggravate obstructive lung disease in any patient taking them. Of the antiinflammatory agents, acetylsalicyclic acid can produce several different airway and parenchymal complications, including aggrevation of asthma in up to 5% of patients with asthma, a noncardiac pulmonary edema when levels exceed 40 mg/dl, and a pseudosepsis syndrome. More than 200 products contain aspirin. Low-dose methotrexate is proving to be a problem because granulomatous interstitial pneumonitis develops in 5% of those patients receiving it. This condition occurs most often in patients receiving the drug for rheumatoid arthritis, but it has been reported in a few patients receiving it for refractory asthma. Chemotherapeutic drug-induced lung disease is almost always associated with fever, thus mimicking opportunistic infection, which is the most common cause of pulmonary complications in the immunocompromised host. However, in 10% to 15% of patients, the pulmonary infiltrate is due to an adverse effect from a chemotherapeutic agent. This complication is frequently fatal even when recognized early.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8174459

Rosenow, E C

1994-05-01

17

Particle-Induced Pulmonary Acute Phase Response Correlates with Neutrophil Influx Linking Inhaled Particles and Cardiovascular Risk  

PubMed Central

Background Particulate air pollution is associated with cardiovascular disease. Acute phase response is causally linked to cardiovascular disease. Here, we propose that particle-induced pulmonary acute phase response provides an underlying mechanism for particle-induced cardiovascular risk. Methods We analysed the mRNA expression of Serum Amyloid A (Saa3) in lung tissue from female C57BL/6J mice exposed to different particles including nanomaterials (carbon black and titanium dioxide nanoparticles, multi- and single walled carbon nanotubes), diesel exhaust particles and airborne dust collected at a biofuel plant. Mice were exposed to single or multiple doses of particles by inhalation or intratracheal instillation and pulmonary mRNA expression of Saa3 was determined at different time points of up to 4 weeks after exposure. Also hepatic mRNA expression of Saa3, SAA3 protein levels in broncheoalveolar lavage fluid and in plasma and high density lipoprotein levels in plasma were determined in mice exposed to multiwalled carbon nanotubes. Results Pulmonary exposure to particles strongly increased Saa3 mRNA levels in lung tissue and elevated SAA3 protein levels in broncheoalveolar lavage fluid and plasma, whereas hepatic Saa3 levels were much less affected. Pulmonary Saa3 expression correlated with the number of neutrophils in BAL across different dosing regimens, doses and time points. Conclusions Pulmonary acute phase response may constitute a direct link between particle inhalation and risk of cardiovascular disease. We propose that the particle-induced pulmonary acute phase response may predict risk for cardiovascular disease.

Saber, Anne Thoustrup; Lamson, Jacob Stuart; Jacobsen, Nicklas Raun; Ravn-Haren, Gitte; Hougaard, Karin S?rig; Nyendi, Allen Njimeri; Wahlberg, Pia; Madsen, Anne Mette; Jackson, Petra; Wallin, Hakan; Vogel, Ulla

2013-01-01

18

In-Situ Counting of Process-Induced Particles  

Microsoft Academic Search

A flow-cell-type portable laser particle counter was developed for in-situ counting of process-induced particles. We measured process-induced particles when small amounts of moisture and oxygen were intentionally added to SiH4 diluted to 10% in argon gas. It was found that there existed a threshold concentration for particle generation caused by the reaction between SiH4 and moisture\\/oxygen; i.e., the number of

Kaoru Kondo; Kazuo Ichijo; Keisuke Shinohara; Tamio Hoshina; Kazuo Tsubouchi; Kazuya Masu

1992-01-01

19

Calcium oxalate nephrolithiasis, a free or fixed particle disease  

Microsoft Academic Search

Calcium oxalate nephrolithiasis, a free or fixed particle disease. The chances of stone formation occurring through a free particle mechanism were calculated using the approach of Finlayson and Reid [1]. For these calculations we used new data on nephron dimensions, supersaturation and crystal growth rates in urine, and also incorporated the size increasing effect of crystal agglomeration. The calculations were

Dirk J Kok; Saeed R Khan

1994-01-01

20

Rosmarinic acid inhibits lung injury induced by diesel exhaust particles.  

PubMed

Epidemiological and experimental studies have suggested that diesel exhaust particles (DEP) may be involved in recent increases in lung diseases. DEP has been shown to generate reactive oxygen species. Intratracheal instillation of DEP induces lung inflammation and edema in mice. Rosmarinic acid is a naturally occurring polyphenol with antioxidative and anti-inflammatory activities. We investigated the effects of rosmarinic acid on lung injury induced by intratracheal administration of DEP (500 microg/body) in mice. Oral supplementation with administration of rosmarinic acid (2 mg/body for 3 d) inhibited DEP-induced lung injury, which was characterized by neutrophil sequestration and interstitial edema. DEP enhanced the lung expression of keratinocyte chemoattractant (KC), interleukin-1beta, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1alpha, which was inhibited by treatment with rosmarinic acid. DEP enhanced expression of iNOS mRNA and formation of nitrotyrosine and 8-OHdG in the lung, which was also inhibited by rosmarinic acid. These results suggest that rosmarinic acid inhibits DEP-induced lung injury by the reduction of proinflammatory molecule expression. Antioxidative activities of rosmarinic acid may also contribute to its protective effects. PMID:12684091

Sanbongi, Chiaki; Takano, Hirohisa; Osakabe, Naomi; Sasa, Naoko; Natsume, Midori; Yanagisawa, Rie; Inoue, Ken-ichiro; Kato, Yoji; Osawa, Toshihiko; Yoshikawa, Toshikazu

2003-04-15

21

Effect of induced surface charge of metal particles on particle sizing by resistive pulse sensing technique.  

PubMed

Effect of induced surface charge of metal particles on particle sizing by Resistive Pulse Sensing (RPS) technique is reported in this paper. The relationship between the magnitude of the RPS signal and the applied voltage was experimentally studied with 5?m polystyrene particles and 5?m magnetic particles in a microfluidic chip. It is shown that the magnitude of RPS signal of the magnetic particles is larger than that of the polystyrene particle under the same measuring voltage. This may be understood by the induced thicker electrical double layer (EDL) around the magnetic particles. This effect is important and should be considered when sizing metal particles and other highly-polarizable particles by using the RPS technique. PMID:24703663

Song, Yongxin; Wang, Chengfa; Sun, Runzhe; Pan, Xinxiang; Li, Dongqing

2014-06-01

22

Role of Inhaled Particles in the Pathophysiology of Cardiovascular Disease.  

National Technical Information Service (NTIS)

The mechanisms by which particulate matter (PM) exposure disrupts cardiac function and worsens cardiovascular disease (CVD) are not well understood. There is a growing body of knowledge that suggests that PM exposure can induce inflammatory changes in blo...

M. Kleinman

2010-01-01

23

Virus-induced autoimmune disease  

Microsoft Academic Search

The braking of tolerance or unresponsiveness to self-antigens, involving the activation of autoreactive lymphocytes, is a critical event leading to autoimmune diseases. The precise mechanisms by which this can occur are mostly unknown. Viruses have been implicated in this process, among other etiological factors, such as genetic predisposition and cytokine activity. Several ways have been proposed by which a viral

Matthias G von Herrath; Michael BA Oldstone

1996-01-01

24

Inducible rodent models of acquired podocyte diseases.  

PubMed

Glomerular diseases remain the leading cause of chronic and end-stage kidney disease. Significant advances in our understanding of human glomerular diseases have been enabled by the development and better characterization of animal models. Diseases of the glomerular epithelial cells (podocytes) account for the majority of proteinuric diseases. Rodents have been extensively used experimentally to better define mechanisms of disease induction and progression, as well as to identify potential targets and therapies. The development of podocyte-specific genetically modified mice has energized the research field to better understand which animal models are appropriate to study acquired podocyte diseases. In this review we discuss inducible experimental models of acquired nondiabetic podocyte diseases in rodents, namely, passive Heymann nephritis, puromycin aminonucleoside nephrosis, adriamycin nephrosis, liopolysaccharide, crescentic glomerulonephritis, and protein overload nephropathy models. Details are given on the model backgrounds, how to induce each model, the interpretations of the data, and the benefits and shortcomings of each. Genetic rodent models of podocyte injury are excluded. PMID:18784259

Pippin, Jeffrey W; Brinkkoetter, Paul T; Cormack-Aboud, Fionnualla C; Durvasula, Raghu V; Hauser, Peter V; Kowalewska, Jolanta; Krofft, Ronald D; Logar, Christine M; Marshall, Caroline B; Ohse, Takamoto; Shankland, Stuart J

2009-02-01

25

Energy and Particle Densities from Oxygen-Induced Nuclear Reactions.  

National Technical Information Service (NTIS)

Charged particle multiplicity and pseudo-rapidity distributions observed in (16)O induced nuclear collisions at 60 and 200 A GeV are presented in conjunction with forward and transverse energy distributions. From the measurements estimates of the supreme ...

S. Garpman R. Albrecht T. C. Awes C. Baktash P. Beckmann

1988-01-01

26

Pan-caspase inhibition suppresses polyethylene particle-induced osteolysis  

Microsoft Academic Search

Particle-induced osteolysis is a major cause of aseptic loosening after total joint replacement. Earlier studies demonstrated\\u000a apoptotic macrophages, giant cells, fibroblasts and T-lymphocytes in capsules and interface membranes of patients with aseptic\\u000a hip implant loosening. The aim of the current study was to determine in a murine calvarial model of wear particle-induced\\u000a osteolysis whether inhibition of apoptosis using the pan-caspase

Stefan Landgraeber; Sandra Jaeckel; Franz Löer; Christian Wedemeyer; Gero Hilken; Ali Canbay; Martin Totsch; Marius von Knoch

2009-01-01

27

Immunotherapy of Human Papilloma Virus Induced Disease  

PubMed Central

Immunotherapy is the generic name for treatment modalities aiming to reinforce the immune system against diseases in which the immune system plays a role. The design of an optimal immunotherapeutic treatment against chronic viruses and associated diseases requires a detailed understanding of the interactions between the target virus and its host, in order to define the specific strategies that may have the best chance to deliver success at each stage of disease. Recently, a first series of successes was reported for the immunotherapy of Human Papilloma Virus (HPV)-induced premalignant diseases but there is definitely room for improvement. Here I discuss a number of topics that in my opinion require more study as the answers to these questions allows us to better understand the underlying mechanisms of disease and as such to tailor treatment.

van der Burg, Sjoerd H

2012-01-01

28

Shock-induced deformation in wetted particle beds  

NASA Astrophysics Data System (ADS)

The high-strain-rate response of granular media has received considerable attention due to increasing interest in granular penetration. In the present study, we investigate the response of wetted packed particle beds under varying flyer plate-induced shock loadings. We investigate the critical conditions for the onset of particle deformation in systems of spherical macroscopic glass beads. Resulting particle deformations from the shock compression are characterized using microscopy as well as particle size analysis, and the effects of shock strength are compared. A fracturing response with a bimodal particle distribution is observed, with an increasing shift to the lower particle size range as shock loading is initially increased. As the transmitted shock pressure exceeds 1 GPa, a significant decrease in the mean particle size is observed.

Marr, Bradley J.; Petel, Oren E.; Frost, David L.; Higgins, Andrew J.; Ringuette, Sophie

2014-05-01

29

Intrinsic particle-induced lateral transport in microchannels.  

PubMed

In microfluidic systems at low Reynolds number, the flow field around a particle is assumed to maintain fore-aft symmetry, with fluid diverted by the presence of a particle, returning to its original streamline downstream. This current model considers particles as passive components of the system. However, we demonstrate that at finite Reynolds number, when inertia is taken into consideration, particles are not passive elements in the flow but significantly disturb and modify it. In response to the flow field, particles translate downstream while rotating. The combined effect of the flow of fluid around particles, particle rotation, channel confinement (i.e., particle dimensions approaching those of the channel), and finite fluid inertia creates a net recirculating flow perpendicular to the primary flow direction within straight channels that resembles the well-known Dean flow in curved channels. Significantly, the particle generating this flow remains laterally fixed as it translates downstream and only the fluid is laterally transferred. Therefore, as the particles remain inertially focused, operations can be performed around the particles in a way that is compatible with downstream assays such as flow cytometry. We apply this particle-induced transfer to perform fluid switching and mixing around rigid microparticles as well as deformable cells. This transport phenomenon, requiring only a simple channel geometry with no external forces to operate, offers a practical approach for fluid transfer at high flow rates with a wide range of applications, including sample preparation, flow reaction, and heat transfer. PMID:22761309

Amini, Hamed; Sollier, Elodie; Weaver, Westbrook M; Di Carlo, Dino

2012-07-17

30

Intrinsic particle-induced lateral transport in microchannels  

PubMed Central

In microfluidic systems at low Reynolds number, the flow field around a particle is assumed to maintain fore-aft symmetry, with fluid diverted by the presence of a particle, returning to its original streamline downstream. This current model considers particles as passive components of the system. However, we demonstrate that at finite Reynolds number, when inertia is taken into consideration, particles are not passive elements in the flow but significantly disturb and modify it. In response to the flow field, particles translate downstream while rotating. The combined effect of the flow of fluid around particles, particle rotation, channel confinement (i.e., particle dimensions approaching those of the channel), and finite fluid inertia creates a net recirculating flow perpendicular to the primary flow direction within straight channels that resembles the well-known Dean flow in curved channels. Significantly, the particle generating this flow remains laterally fixed as it translates downstream and only the fluid is laterally transferred. Therefore, as the particles remain inertially focused, operations can be performed around the particles in a way that is compatible with downstream assays such as flow cytometry. We apply this particle-induced transfer to perform fluid switching and mixing around rigid microparticles as well as deformable cells. This transport phenomenon, requiring only a simple channel geometry with no external forces to operate, offers a practical approach for fluid transfer at high flow rates with a wide range of applications, including sample preparation, flow reaction, and heat transfer.

Amini, Hamed; Sollier, Elodie; Weaver, Westbrook M.; Di Carlo, Dino

2012-01-01

31

Shear-induced diffusion of platelike particles in microchannels.  

PubMed

We exploit the recent developments of microfluidic technologies to investigate the collective shear-induced diffusion in suspensions of micron-sized particles. Whereas spherical particles do not diffuse on the time scale of our experiments, the results with platelike clay particles show a strong cross-stream shear-induced diffusivity at low volume fraction (phi{0}particle concentration. These data are in good agreement with previous experimental and theoretical results for spheres when rescaled with the particle number density. PMID:19113714

Rusconi, Roberto; Stone, Howard A

2008-12-19

32

Method for ion implantation induced embedded particle formation via reduction  

DOEpatents

A method for ion implantation induced embedded particle formation via reduction with the steps of ion implantation with an ion/element that will chemically reduce the chosen substrate material, implantation of the ion/element to a sufficient concentration and at a sufficient energy for particle formation, and control of the temperature of the substrate during implantation. A preferred embodiment includes the formation of particles which are nano-dimensional (<100 m-n in size). The phase of the particles may be affected by control of the substrate temperature during and/or after the ion implantation process.

Hampikian, Janet M (Decatur, GA); Hunt, Eden M (Atlanta, GA)

2001-01-01

33

Inducing Lift on Spherical Particles by Traveling Magnetic Fields  

NASA Technical Reports Server (NTRS)

Gravity induced sedimentation of suspensions is a serious drawback to many materials and biotechnology processes, a factor that can, in principle, be overcome by utilizing an opposing Lorentz body force. In this work we demonstrate the utility of employing a traveling magnetic field (TMF) to induce a lifting force on particles dispersed in the fluid. Theoretically, a model has been developed to ascertain the net force, induced by TMF, acting on a spherical body as a function of the fluid medium's electrical conductivity and other parameters. Experimentally, the model is compared to optical observations of particle motion in the presence of TMF.

Mazuruk, Konstantin; Grugel, Richard N.; Rose, M. Franklin (Technical Monitor)

2001-01-01

34

Inducing Lift on Spherical Particles by Traveling Magnetic Fields  

NASA Technical Reports Server (NTRS)

Gravity induced sedimentation of suspensions is a serious drawback to many materials and biotechnology processes, a factor that can, in principle, be overcome by utilizing an opposing Lorentz body force. In this work we demonstrate the utility of employing a traveling magnetic field (TMF) to induce a lifting force on particles dispersed in the fluid. Theoretically, a model has been developed to ascertain the net force, induced by TMF, acting on a spherical body as a function of the fluid medium's electrical conductivity and other parameters. Experimentally, the model is compared to optical observations of particle motion in the presence of TMF.

Mazuruk, Konstantin; Grugel, Richard N.; Rose, M. Franklin (Technical Monitor)

2000-01-01

35

Transient Flow Induced by the Adsorption of Particles  

NASA Astrophysics Data System (ADS)

When small particles, e.g., glass, flour, pollen, etc., come in contact with a fluid-liquid interface they disperse so quickly to form a monolayer on the interface that it appears explosive, especially on the surface of mobile liquids like water. This is a consequence of the fact that the adsorption of a particle in an interface causes a lateral flow which on the interface away from the particle. In this study we use the particle image velocimetry (PIV) technique to measure the transient three-dimensional flow that arises due to the adsorption of spherical particles. The PIV measurements show that the flow develops a fraction of a second after the adsorption of the particle and persists for several seconds. The fluid below the particle rises upwards and on the surface moves away from the particle. These latter PIV results are consistent with the surface velocity measurements performed in earlier studies. The strength of the induced flow, and the time duration for which the flow persists, both decrease with decreasing particle size. For a spherical particle the flow is axisymmetric about the vertical line passing through the center of the particle.

Musunuri, Naga; Codjoe, Daniel; Dalal, Bhavin; Fischer, Ian; Singh, Pushpendra

2013-03-01

36

Aeolian Induced Erosion and Particle Entrainment  

NASA Technical Reports Server (NTRS)

The Granular Physics Department at The Kennedy Space Center is addressing the problem of erosion on the lunar surface. The early stages of research required an instrument that would produce erosion at a specific rate with a specific sample variation. This paper focuses on the development and experimental procedures to measure and record erosion rates. This was done with the construction of an open air wind tunnel, and examining the relationship between airflow and particle motion.

Saint, Brandon

2007-01-01

37

Induced-Charge Electrophoresis of Metallodielectric Particles  

Microsoft Academic Search

The application of AC electric fields in aqueous suspensions of anisotropic\\u000aparticles leads to unbalanced liquid flows and nonlinear, induced-charge\\u000aelectrophoretic (ICEP) motion. We report experimental observations of the\\u000amotion of \\

Sumit Gangwal; Olivier J. Cayre; Martin Z. Bazant; Orlin D. Velev

2008-01-01

38

Disease control by means of induced resistance.  

PubMed

The biological control of fungal diseases in agriculture and horticulture based on induced resistance can become an attractive alternative to traditional fungicides. The principle is that all plants have genetic information about resistance mechanisms against pathogens such as fungi, viruses, and bacteria. The purpose of our research is to activate these resistance factors that are latent present in the plant, by treating the plants with abiotic and biotic agents (elicitors) to activate defence responses. The resistance inducing products used in the experiments are based on non-pathogenic rhizobacteria, and metabolites of micro-organisms and plants. In our experiments the different products and organisms were tested against powdery mildew on tomato. Good results are obtained with Milsana, Elexa and Serenade, especially Milsana showed a strong reduction of the disease symptoms of O. lycopersicum. These products could contribute to an environmentally more acceptable crop protection and suits in the aim to durable production techniques in agriculture and horticulture. PMID:12701418

Isebaert, S; Verhoeven, R; Haesaert, G

2002-01-01

39

Pramipexole-induced antecollis in Parkinson's disease  

Microsoft Academic Search

We report a case of antecollis, or dropped head with Parkinson's disease (PD) induced by pramipexole, a nonergot dopamine agonist. An 80-year-old woman presented with progressively severe neck flexion, which developed within a few weeks of taking pramipexole at 3 mg\\/day. She had a disturbed gait and complained of difficulty in daily activity because of restricted visual field and severe stooped

Masahiko Suzuki; Toshiaki Hirai; Yasuhiko Ito; Tsuyoshi Sakamoto; Hisayoshi Oka; Akira Kurita; Kiyoharu Inoue

2008-01-01

40

Shock induced magnetic effects in fine particle iron dispersions  

NASA Technical Reports Server (NTRS)

Magnetic effects associated with shock induced transformation of fcc antiferromagnetic iron precipitates in polycrystalline copper disks at levels up to 5 GPa in weak magnetic fields (H not greater than 0.5 Oe) were investigated. The demagnetization and anisotropy associated with second order transition, the effects of plastic deformation in imparting magnetic anisotropy and magnetic hardening, and the influence of post shock thermal transients on magnetization associated with recovery, recrystallization and grain growth were studied. It was found that on the microsecond time scale of the shock induced first order transformation, the field sense is recorded in the transformed iron particles. For a given particle size the degree of transformation of fcc iron depends on the level of the shock. For a given shock level the resultant magnetic properties depend on the particle size distribution, with maximum effects noted in specimens with 400 to 600 A particles.

Wasilewski, P. J.

1979-01-01

41

Flow induced particle separation in turbulent channel flow  

NASA Astrophysics Data System (ADS)

Particle separation has been an issue in many engineering disciplines and applications, due to purity requirements in pre-treatment processes, or in post-reacting flows. Several methods have been invented, with use of additional equipment, by employing effects of electric field, centrifugal force etc. Our study finds that turbulence, which has been found to provide excellent mixing efficiency, could separate particles with different Schmidt numbers, Sc, with no use of outside force or devices. Direct numerical simulation is used with tracking of scalar markers (Lagrangian scalar tracking, LST) to obtain particle positions as they move in a flow. Particles with different Sc have different values of dispersion. Because of this, mixed clouds of particles with different Sc, after a long enough time, will result in separate clouds of particles with different Sc. The efficiency of separation is effected by the distance from the wall at which particles are released into the flow and by the difference in Sc between particles. The reason for this flow-induced separation will be discussed, and its relation to the development process of instantaneous puffs of particles. Criteria for a successful separation will also be discussed..

Nguyen, Quoc; Srinvasan, Chiranth; Papavassiliou, Dimitrios

2013-03-01

42

Particle-induced amorphization complex ceramic  

SciTech Connect

The presently funded three-year research program, supported by the Division of Materials Sciences of the Office of Basic Energy Sciences, was initiated on August 1, 1993; during the period in which the grant will have been active, $249,561 of support have been provided to date with an additional $79,723 to be spent during the third, final year (ending July 30, 1996). The primary purpose of the program is to develop an understanding of heavy-particle radiation effects -- {alpha}-recoil nuclei, fission fragments, ion-irradiations -- on ceramic materials and the thermal annealing mechanisms by which crystallinity might be restored. During the past two years, we have completed major studies on zircon (ZrSiO{sub 4}), olivine (Mg{sub 2}SiO{sub 4} and ten other compositions), spinel (MgAl{sub 2}O{sub 4} and four other compositions), and silica polymorphs (quartz, coesite and stishovite), as well as berlinite (AlPO{sub 4}) which is isomorphous with quartz. In addition, based on the above research, we propose the use of zircon as a host phase for the immobilization of plutonium resulting from weapons dismantlement.

Ewing, R.C.; Wang, Lu-Min

1996-02-16

43

Environmentally induced autoimmune diseases: potential mechanisms.  

PubMed Central

Environmental and other xenobiotic agents can cause autoimmunity. Examples include drug-induced lupus, toxic oil syndrome, and contaminated l-tryptophan ingestion. Numerous mechanisms, based on (italic)in vitro(/italic) evidence and animal models, have been proposed to explain how xenobiotics induce or accelerate autoimmunity. The majority of these can be divided into three general categories. The first is those inhibiting the processes involved in establishing tolerance by deletion. Inhibiting deletion can result in the release of newly generated autoreactive cells into the periphery. The second mechanism is the modification of gene expression in the cells participating in the immune response, permitting lymphocytes to respond to signals normally insufficient to initiate a response or allowing the antigen-presenting cells to abnormally stimulate a response. Abnormal gene expression can thus disrupt tolerance maintained by suppression or anergy, permitting activation of autoreactive cells. The third is the modification of self-molecules such that they are recognized by the immune system as foreign. Examples illustrating these concepts are presented, and related mechanisms that have the potential to similarly affect the immune system are noted. Some mechanisms appear to be common to a variety of agents, and different mechanisms appear to produce similar diseases. However, evidence that any of these mechanisms are actually responsible for xenobiotic-induced human autoimmune disease is still largely lacking, and the potential for numerous and as yet unidentified mechanisms also exists.

Rao, T; Richardson, B

1999-01-01

44

A compilation of charged-particle induced thermonuclear reaction rates  

Microsoft Academic Search

Low-energy cross section data for 86 charged-particle induced reactions involving light (1 ? Z ? 14), mostly stable, nuclei are compiled. The corresponding Maxwellian-averaged thermonuclear reaction rates of relevance in astrophysical plasmas at temperatures in the range from 106 K to 1010 K are calculated. These evaluations assume either that the target nuclei are in their ground state, or that

C. Angulo; M. Arnould; M. Rayet; P. Descouvemont; D. Baye; C. Leclercq-Willain; A. Coc; S. Barhoumi; P. Aguer; C. Rolfs; R. Kunz; J. W. Hammer; A. Mayer; T. Paradellis; S. Kossionides; C. Chronidou; K. Spyrou; S. Degl'Innocenti; G. Fiorentini; B. Ricci; S. Zavatarelli; C. Providencia; H. Wolters; J. Soares; C. Grama; J. Rahighi; A. Shotter; M. Lamehi Rachti

1999-01-01

45

Phason-induced dynamics of colloidal particles on quasicrystalline substrates.  

PubMed

Phasons are special hydrodynamic modes that occur in quasicrystals. The trajectories of particles due to a phasonic drift were recently studied by Kromer et al. (Phys. Rev. Lett. 108, 218301 (2012)) for the case where the particles stay in the minima of a quasicrystalline potential. Here, we study the mean motion of colloidal particles in quasicrystalline laser fields when a phasonic drift or displacement is applied and also consider the cases where the colloids cannot follow the potential minima. While the mean square displacement is similar to the one of particles in a random potential with randomly changing potential wells, there also is a net drift of the colloids that reverses its direction when the phasonic drift velocity is increased. Furthermore, we explore the dynamics of the structural changes in a laser-induced quasicrystal during the rearrangement process that is caused by a steady phasonic drift or an instantaneous phasonic displacement. PMID:23512714

A Kromer, Justus; Schmiedeberg, Michael; Roth, Johannes; Stark, Holger

2013-03-01

46

Bisphosphonates in bone cement inhibit PMMA particle induced bone resorption  

PubMed Central

OBJECTIVE—Wear particle induced bone resorption is thought to be one of the mechanisms that contribute to implant loosening. It has previously been shown that macrophages, in response to polymethylmethacrylate (PMMA) particles, differentiate into bone resorbing osteoclasts, and that this process is inhibited by a bisphosphonate, etidronate (EHDP). The aim of this study was to determine whether incorporating EHDP in bone cement could reduce PMMA associated bone resorption.?METHODS—Two concentrations of EHDP were mixed with PMMA monomer before polymerisation. Particles of PMMA (1-10 µm) were generated then added to mouse monocytes cocultured with UMR106 rat osteoblast-like cells and the extent of osteoclast differentiation was determined by assessing the extent of tartrate resistant acid phosphatase (TRAP) staining and measuring the amount of lacunar bone resorption.?RESULTS—The addition of PMMA to monocyte-UMR106 cocultures resulted in a marked increase in the number of TRAP positive osteoclast-like cells and a significant increase in the number of lacunar resorption pits compared with control cultures to which no particles had been added. After the addition of particles of PMMA + 20 mg EHDP, significantly fewer lacunar pits (p=0.00006) and fewer TRAP positive cells were noted compared with cocultures containing PMMA particles alone.?CONCLUSIONS—These results indicate that by mixing a bisphosphonate with bone cement, it is possible to inhibit PMMA particle induced bone resorption. This bisphosphonate inhibition of PMMA biomaterial wear particle containing macrophage-osteoclast differentiation and bone resorption may provide a possible therapeutic strategy to prevent or to control the osteolysis of aseptic loosening.?? Keywords: bisphosphonate; bone resorption; aseptic loosening; macrophages

Sabokbar, A.; Fujikawa, Y.; Murray, D.; Athanasou, N.

1998-01-01

47

Obese mice are resistant to eosinophilic airway inflammation induced by diesel exhaust particles.  

PubMed

Particulate matter can exacerbate respiratory diseases such as asthma. Diesel exhaust particles are the substantial portion of ambient particulate matter with a <2.5?µm diameter in urban areas. Epidemiological data indicate increased respiratory health effects of particulate matter in obese individuals; however, the association between obesity and diesel exhaust particle-induced airway inflammation remains unclear. We aimed to investigate the differences in susceptibility to airway inflammation induced by exposure to diesel exhaust particles between obese mice (db/db) and lean mice (db/+m). Female db/db and db/+m mice were intratracheally administered diesel exhaust particles or vehicle every 2?weeks for a total of seven times. The cellular profile of bronchoalveolar lavage fluid and histological changes in the lungs were assessed and the lungs and serum were analyzed for the generation of cytokines, chemokines and soluble intercellular adhesion molecule 1. Diesel exhaust particle exposure-induced eosinophilic infiltration in db/+m mice accompanied by T-helper 2 cytokine, chemokine and soluble intercellular adhesion molecule 1 expression in the lungs. In contrast, it induced mild neutrophilic airway inflammation accompanied by elevated cytokines and chemokines in db/db mice. The lungs of db/db mice exhibited decreased expression of eosinophil activators/chemoattractants such as interleukin-5, interleukin-13 and eotaxin compared with those of db/+m mice. In addition, serum eotaxin and monocyte chemotactic protein-1 levels were significantly higher in db/db mice than in db/+m mice. In conclusion, obesity can affect susceptibility to diesel exhaust particle-induced airway inflammation, which is possibly due to differences in local and systemic inflammatory responses between lean and obese individuals. Copyright © 2013 John Wiley & Sons, Ltd. PMID:24105835

Yanagisawa, Rie; Koike, Eiko; Ichinose, Takamichi; Takano, Hirohisa

2014-06-01

48

Neutral Particle Emission Induced by Solar Wind in Mercury's Environment  

NASA Astrophysics Data System (ADS)

The peculiar configuration of the Hermean magnetosphere, characterised by a weak magnetic field, may allow a solar wind entrance and circulation in Mercury's environment. More particularly, intense ion fluxes are expected in the cusp regions, which are extremely large if compared to the Earth's ones. In the present study we reconstruct the H+ distribution in space, energy and pitch angle by means of a single-particle Monte-Carlo model. The neutral particle emission induced by the solar wind in the Hermean environment is investigated as well. The H+ are likely to rapidly leave the Hermean magnetosphere or precipitate onto the surface of the planet, thus originating neutral particle emission via ion-sputtering as well as energetic neutral atoms, generated via charge-exchange process. Different external configurations of both interplanetary magnetic field and cross-tail potential drop result in variations of the sputtered and charge-exchange neutral particle signal. The Neutral Particle Analyser - Ion Spectrometer experiment (NPA-IS/SERENA), proposed to fly on board of the ESA mission Bepi Colombo, will monitor the circulating ion and neutral particles. The modeled distributions here presented have been processed in the frame of SERENA instrument and may be considered as a reference tool for the future observations.

Mura, A.; Orsini, S.; Milillo, A.; Delcourt, D.

2004-05-01

49

[Particles in the outside air increase the risk of cardiovascular diseases].  

PubMed

Evidence accumulated during the mid-1990 s that ambient particulate air pollution aerosol particles may not only exacerbate respiratory diseases but also be a risk factor for cardiovascular disease exacerbation. The aim of the studies described here was to assess the impact of the 1985 smog episode on the risk factor profile in the randomly selected population-based sample of the MONICA survey 1984/85 (S1). During a 13-day period in January 1985 sulphur dioxide concentrations increased four times and concentrations of total suspended atmospheric particles doubled. The impact of this time period on plasma viscosity, plasma C-reactive protein concentrations, heart rate and blood pressure was investigated. Regression models were used to assess these associations adjusting for individual risk factors such as gender, age, body mass index, serum total cholesterol and HDL-cholesterol, smoking, physical activity and medication for cardiovascular diseases and for weather conditions during the survey period. An increase in plasma viscosity, C-reactive protein and heart rate was estimated during the air pollution episode. There was also an increase in blood pressure, but this appeared to be attributable to the weather conditions during the air pollution episode. All the four outcomes were associated with the sulphur dioxide concentrations and the total suspended particle concentrations during the survey. These results indicate that ambient air pollution, particularly ambient particulate air pollution may induce systemic inflammation and modulate the autonomic function of the heart. These pathomechanisms may contribute to the observed associations between ambient air pollution concentrations and cardiovascular disease exacerbation such as hospitalisation and mortality due to cardiovascular diseases. PMID:16032522

Peters, A

2005-08-01

50

Comparison of toroidicity-induced Alfvén eigenmodes and energetic particle modes by gyrokinetic particle simulations  

SciTech Connect

This work reports on linear global gyrokinetic particle simulations of the excitation of toroidicity-induced Alfvén eigenmodes (TAE) and energetic particle modes (EPM), and the comparison between these two modes. The TAE excitation by antenna clarifies the magnetohydrodynamic (MHD) mode structure and the discrete eigenmode exists in the gap between the upper and lower accumulation points. The TAE excitation by fast ions modifies the MHD mode structure because of radial symmetry breaking and the eigenmode frequency moves towards the lower accumulation point. The phase space structure of fast ions shows that both passing and trapped particles contribute to the TAE excitation and that trapped particles dominate the wave-particle resonance in our simulations. The growth rate of TAE is sensitive to the fast ion energy, density, and density gradient, which are also important factors contributing to the transition of the TAE to the EPM. The gyrokinetic particle simulations also confirm the excitation of EPM when the drive is stronger. The frequency of the EPM is determined by the characteristic frequencies of fast ion motion in toroidal geometry.

Zhang, Chenxi; Li, Ding [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China) [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, Wenlu [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China) [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Lin, Zhihong [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States) [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Fusion Simulation Center, Peking University, Beijing 100871 (China)

2013-05-15

51

Nuclear reactions induced by high-energy alpha particles  

NASA Technical Reports Server (NTRS)

Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

Shen, B. S. P.

1974-01-01

52

SENSITIZATION AND EXACERBATION OF ALLERGIC DISEASES BY DIESEL ENGINE PARTICLES  

SciTech Connect

Most studies of the health effects of diesel exhaust have focused on the controversial issue of its role in cancer. However, recently the role of combustion products such as diesel exhaust particles (DEP) in modulating the immune response has garnered much attention. In particular the effect of DEP on allergic and asthmatic diseases has been the focus of many studies. A link between industrialization and allergic disease has long been presumed. Indeed, only 50 years after the first recorded reported case of allergy in 1819, Charles Blackely wrote that the ''hay-fever epidemic'' was associated with the movement of people from the country into the cities. Ishizaki et al. (1987) found that people in Japan living on busy roads lined with cedar trees have more allergies to cedar than residents living on similar streets with much less traffic. Since that time other epidemiological studies have reported similar findings. Kramer, et al., showed that hay fever is greater in residential areas with heavy truck traffic, while Weiland, et al., reported that allergic symptoms correlate with the distance of residences to roads with heavy traffic.

Diaz-Sanchez, David

2000-08-20

53

APOPTOTIC AND INFLAMMATORY EFFECTS INDUCED BY DIFFERENT PARTICLES IN HUMAN ALVEOLAR MACROPHAGES  

EPA Science Inventory

Pollutant particles induce apoptosis and inflammation, but the relationship between these two biological processes is not entirely clear. In this study, we compared the proapoptotic and proinflammatory effects of four particles: residual oil fly ash (ROFA), St. Louis particles SR...

54

Theory of trapped-particle-induced resistive fluid turbulence  

SciTech Connect

A theory of anomalous electron heat transport, evolving from trapped-particle-induced resistive interchange modes, is proposed. These latter are a new branch of the resistive interchange-ballooning family of instabilities, destabilized when the pressure carried by the unfavorably-drifting trapped particles is sufficiently large to overcome stabilizing contributions coming from favorable average curvature. Expressions for the turbulent heat diffusivity and anomalous electron thermal conductivity at saturation are derived for two regimes of trapped particle energy: (1) a moderately-energetic regime, which is ''fluid-like'' in the sense that the unstable mode grows faster than the time that it takes for particles in this energy range to precess once around the torus; and (2) a highly-energetic regime, where the trapped species has sufficiently high energy as to be able to resonantly interact with the mode. Unlike previous theories of anomalous transport, the estimates of diffusion and transport obtained here are self-consistent, since the trapped particles do not ''see'' the magnetic flutter due to their rapid bounce motion. The theory is valid for moderate electron-temperature, high ion-temperature (auxiliary-heated) plasmas, and as such, is relevant for present and future-generation experimental fusion devices.

Biglari, H.; Diamond, P.H.

1987-05-01

55

Theory of trapped-particle-induced resistive fluid turbulence  

SciTech Connect

A theory of anomalous electron heat transport, evolving from trapped-particle-induced resistive interchange modes, is proposed. The latter are a new branch of the resistive interchange-ballooning family of instabilities, destabilized when the pressure carried by the unfavorably drifting trapped particles is sufficiently large to overcome stabilizing contributions coming from favorable average curvature. Expressions for the turbulent heat diffusivity and anomalous electron thermal conductivity at saturation are derived for two regimes of trapped-particle energy: (I) a moderately energetic regime, which is ''fluidlike'' in the sense that the unstable mode grows faster than the time that it takes for particles in this energy range to precess once around the torus, and (II) a highly energetic regime, where the trapped species has sufficiently high energy as to be able to interact resonantly with the mode. Unlike previous theories of anomalous transport, the estimates of diffusion and transport obtained here are self-consistent since the trapped particles do not ''see'' the magnetic flutter due to their rapid bounce motion. The theory is valid for moderate electron-temperature, high ion-temperature (auxiliary heated) plasmas and as such, is relevant for present- and future-generation experimental fusion devices.

Biglari, H.; Diamond, P.H.

1987-12-01

56

[Particle Induced X-ray Emission (PIXE) for analysis of trace elements in biological materials].  

PubMed

Outline of Particle Induced X-ray Emission (PIXE) and its application to biomedical samples are described. Charged particles from cyclotron or van de Graaff generator bombards analytical samples and semiconductor detector measures energy and intensity of induced characteristic x-ray. Simultaneous determination for 22Na to 92U is possible by PIXE. 100 nA of 3 MeV protons bombards biomedical samples and detection limits for almost all trace essential elements are sub microgram/g. Only 1 mg of biomedical sample is necessary for determination of trace elements and no chemical procedure is necessary for preparation of analytical sample. PIXE is powerful tool for determination of essential elements and applied for diagnosis for several diseases. PMID:8587194

Iwata, Y

1996-01-01

57

Particle production in antiproton-induced nuclear reactions  

NASA Astrophysics Data System (ADS)

The quantum molecular dynamics model has been improved to investigate the reaction dynamics induced by antiprotons. The reaction channels of elastic scattering, annihilation, charge exchange, and inelastic collisions have been included in the model. Dynamics on particle production, in particular pions, kaons, antikaons, and hyperons, is investigated in collisions of p¯ on C12, Ne20, Ca40, Sn112, Ta181, Au197, and U238 from a low to high incident momentum. The rapidity and momentum distributions of ?+ and protons from the LEAR measurements can be well reproduced. The impacts of system size and incident momentum on particle emissions are investigated from the inclusive spectra, transverse momentum, and rapidity distributions. It is found that the annihilations of p¯ on nucleons are of importance on the particle production. Hyperons are mainly produced via meson induced reactions on nucleons and strangeness exchange collisions when the incident momentum is below the threshold value of annihilation reaction. A higher nuclear temperature is obtained from the kaon emission, but it has a lower value for hyperon production.

Feng, Zhao-Qing; Lenske, Horst

2014-04-01

58

The EPIC-MOS Particle-Induced Background Spectrum  

NASA Technical Reports Server (NTRS)

We have developed a method for constructing a spectrum of the particle-induced instrumental background of the XMM-Newton EPIC MOS detectors that can be used for observations of the diffuse background and extended sources that fill a significant fraction of the instrument field of view. The strength and spectrum of the particle-induced background, that is, the background due to the interaction of particles with the detector and the detector surroundings, is temporally variable as well as spatially variable over individual chips. Our method uses a combination of the filter-wheel-closed data and a database of unexposed-region data to construct a spectrum of the "quiescent" background. We show that, using this method of background subtraction, the differences between independent observations of the same region of "blank sky" are consistent with the statistical uncertainties except when there is clear evidence of solar wind charge exchange emission. We use the blank sky observations to show that contamination by SWCX emission is a strong function of the solar wind proton flux, and that observations through the flanks of the magnetosheath appear to be contaminated only at much higher solar wind fluxes. We have also developed a spectral model of the residual soft proton flares, which allows their effects to be removed to a substantial degree during spectral fitting.

Kuntz, K. D.; Snowden, S. L.

2006-01-01

59

Solar radiation induced rotational bursting of interplanetary particles  

NASA Technical Reports Server (NTRS)

It is suggested that the magnitudes of the two radiation-induced rotational bursting mechanisms (Radzieskii effect and windmill effect) have been overestimated and that they do not work significantly faster than the Poynting-Robertson effect in removing interplanetary particles. These two mechanisms are described, and serious doubts are raised regarding the derivation of their radiation pressure-torque proportionality constants, which are required for calculating their magnitudes. It is shown that both mechanisms will cause the alignment of elongated particles and, consequently, the polarization of zodiacal light. Since no positive polarization has been measured at the antisolar point, it is concluded that the magnitudes of the rotational bursting mechanisms are smaller than that of the Poynting-Robertson effect.

Sparrow, J. G.

1975-01-01

60

Ion-beam-induced-charge characterisation of particle detectors  

NASA Astrophysics Data System (ADS)

Ion-beam-induced-charge collection (IBIC) in a nuclear microprobe has been used to characterise detectors for the measurement of particles over a median energy range (100 keV-1 MeV). Three standard detector devices have been studied: a PIPS detector with a buried (ion-implanted) junction structure, a Schottky barrier junction device and a PN-junction photodiode. A 2.0 MeV focussed helium ion beam was used to probe the active area of each device with a spatial resolution ˜1-2 ?m, to quantify the thickness of the dead layer, the charge collection response and the reduction in charge collection efficiency induced by ion-beam damage.

Yang, C.; Jamieson, D. N.; Hearne, S. M.; Pakes, C. I.; Rout, B.; Gauja, E.; Dzurak, A. J.; Clark, R. G.

2002-05-01

61

MHD-Induced Alpha Particle Loss in TFTR  

SciTech Connect

MHD-induced increases in alpha particle loss to the wall were observed for both coherent modes and transient reconnection events using an array of scintillator detectors near the wall of Tokamak Fusion Test Reactor (TFTR). The magnitude of the coherent MHD-induced alpha loss as seen by these detectors was normally comparable to the MHD-quiescent first-orbit or toroidal-field ripple loss, but the magnitude of the alpha loss during reconnection events was up to 1000 times higher than this for a short time. Modeling suggest that the coherent MHD loss mechanism will be even less significant for future reactor-scale deuterium-tritium tokamaks due to the smaller ratio of the alpha gyroradius to minor radius.

Darrow, D.S.; Fredrickson, E.D.; Taylor, G.; White, R.B.; Zweben, S.J.; von Goeler, S.

1999-03-01

62

The natural history of histologically proved drug induced liver disease  

Microsoft Academic Search

BACKGROUNDThe long term outcome of drug related liver disease is unknown.AIMSTo study the natural history of histologically proved drug induced hepatotoxicity.METHODS110 patients with liver biopsies coded either as drug induced liver disease or hepatitis\\/cholestasis of unknown aetiology were identified from hospital records 1978–1996. Review of case notes and histology identified 44 patients with definite drug induced hepatotoxicity. Forty surviving patients

P G Aithal; C P Day

1999-01-01

63

Inhaled particles in human disease and animal models: use of electron beam instrumentation.  

PubMed Central

The mineral pneumoconioses (lung disease caused by inhalation of inorganic dust) have been an important disease entity for centuries. In the last several decades, the electron microscope has been used to elucidate the distribution and identification of inhaled minerals, to aid in establishing etiologic factors, and less commonly, to determine the basic biologic mechanisms through which inhaled minerals cause lung disease. In this section, I review the instrumentation and tissue preparation currently used to address some modern problems in particle-induced lung disease. For example, human pneumoconioses of undetermined etiology can be clarified by electron microscopy and X-ray energy spectrometry. In addition, the initial deposition patterns of asbestos and silica are demonstrated in animal models, and the contributions of electron microscopy in establishing the initial lesions of asbestosis are described. Images FIGURE 1. FIGURE 2. FIGURE 3. FIGURE 4. FIGURE 5. FIGURE 6. FIGURE 7. FIGURE 8. FIGURE 9. FIGURE 9. FIGURE 10. FIGURE 11. FIGURE 12. FIGURE 13. FIGURE 14.

Brody, A R

1984-01-01

64

Animal studies of charged particle-induced carcinogenesis.  

PubMed

The distribution of energy deposition in cells and tissues by high-charge, high-energy (HZE) nuclei differs considerably from that of low linear energy transfer (LET) radiation, raising concerns that charged particle exposure may be more efficient in inducing radiogenic cancers or may induce a different spectrum of tumors. The authors have performed a review of charged particle carcinogenesis in animals with the following observations. A limited number of animal studies with carcinogenesis endpoints have been performed to evaluate the effectiveness of HZE ions. These include the induction of skin and mammary tumors in the rat and Harderian gland tumors, acute myeloid leukemia (AML), and hepatocellular carcinomas in the mouse. In general, high relative biological effectiveness (RBE) has been reported for solid tumor induction. RBE dependence on HZE radiation quality has been most extensively characterized in studies of mouse Harderian gland tumorigenesis. In this model, the RBE increases with LET and plateaus in the 193-953 keV ?m(-1) range. Unlike the results of solid tumor studies, a leukemogenesis study found 1 GeV nucleon(-1) 56Fe ions no more efficient than gamma-rays for AML induction. No novel tumor types have been observed in HZE irradiated animals as compared with those that occur spontaneously or following low-LET radiation exposures. Genetic background of the irradiated animals is critical; the tumor types induced in HZE irradiated mice depend on their strain background, and the incidence of HZE ion-induced mammary carcinogenesis in the rat is also strain dependent. PMID:23032886

Bielefeldt-Ohmann, Helle; Genik, Paula C; Fallgren, Christina M; Ullrich, Robert L; Weil, Michael M

2012-11-01

65

Asian Dust Particles Induce Macrophage Inflammatory Responses via Mitogen-Activated Protein Kinase Activation and Reactive Oxygen Species Production  

PubMed Central

Asian dust is a springtime meteorological phenomenon that originates in the deserts of China and Mongolia. The dust is carried by prevailing winds across East Asia where it causes serious health problems. Most of the information available on the impact of Asian dust on human health is based on epidemiological investigations, so from a biological standpoint little is known of its effects. To clarify the effects of Asian dust on human health, it is essential to assess inflammatory responses to the dust and to evaluate the involvement of these responses in the pathogenesis or aggravation of disease. Here, we investigated the induction of inflammatory responses by Asian dust particles in macrophages. Treatment with Asian dust particles induced greater production of inflammatory cytokines interleukin-6 and tumor necrosis factor-? (TNF-?) compared with treatment with soil dust. Furthermore, a soil dust sample containing only particles ?10??m in diameter provoked a greater inflammatory response than soil dust samples containing particles >10??m. In addition, Asian dust particles-induced TNF-? production was dependent on endocytosis, the production of reactive oxygen species, and the activation of nuclear factor-?B and mitogen-activated protein kinases. Together, these results suggest that Asian dust particles induce inflammatory disease through the activation of macrophages.

Higashisaka, Kazuma; Fujimura, Maho; Taira, Mayu; Yoshida, Tokuyuki; Tsunoda, Shin-ichi; Baba, Takashi; Yamaguchi, Nobuyasu; Nabeshi, Hiromi; Yoshikawa, Tomoaki; Nasu, Masao; Tsutsumi, Yasuo

2014-01-01

66

Radiation-induced coronary artery disease  

SciTech Connect

This report describes three patients who developed myocardial infarction at an untimely age, 4 to 12 years after radiation therapy for Hodgkin's disease. These cases lend credence to the cause and effect relation of such therapy to coronary artery disease.

Dunsmore, L.D.; LoPonte, M.A.; Dunsmore, R.A.

1986-07-01

67

Induced radioactivity in and around high-energy particle accelerators.  

PubMed

Particle accelerators and their surroundings are locations of residual radioactivity production that is induced by the interaction of high-energy particles with matter. This paper gives an overview of the principles of activation caused at proton accelerators, which are the main machines operated at Conseil Européen pour la Recherche Nucléaire. It describes the parameters defining radio-nuclide production caused by beam losses. The second part of the paper concentrates on the analytic calculation of activation and the Monte Carlo approach as it is implemented in the FLUKA code. Techniques used to obtain, on the one hand, estimates of radioactivity in Becquerel and, on the other hand, residual dose rates caused by the activated material are discussed. The last part of the paper focuses on experiments that allow for benchmarking FLUKA activation calculations and on simulations used to predict activation in and around high-energy proton machines. In that respect, the paper addresses the residual dose rate that will be induced by proton-proton collisions at an energy of two times 7 TeV in and around the Compact Muon Solenoid (CMS) detector. Besides activation of solid materials, the air activation expected in the CMS cavern caused by this beam operation is also discussed. PMID:21697180

Vincke, Helmut; Theis, Chris; Roesler, Stefan

2011-07-01

68

Theoretical and experimental examination of particle-particle interaction effects on induced dipole moments and dielectrophoretic responses of multiple particle chains.  

PubMed

Dielectrophoresis (DEP), an electrokinetic phenomenon based on particle polarizations in nonuniform electric fields, is increasingly employed for particle and cell characterizations and manipulations in microdevices. However, particle number densities are rarely varied and particle-particle interactions are largely overlooked, but both affect particle's effective polarizations by changing the local electric field, which directly impacts particle assembly into chains. This work examines theoretical and experimental particle-particle interactions and dielectrophoretic responses in nonuniform electric fields, then presents individual and chain velocities of spherical polystyrene microparticles and red blood cells (RBCs) under DEP forces in a modified quadruple electrode microdevice. Velocities are independently compared between 1, 2, 3, and 4 polystyrene beads and RBCs assembled into chains aligned with the electric field. Simulations compared induced dipole moments for particles experiencing the same (single point) and changing (multiple points) electric fields. Experiments and simulations are compared by plotting DEP velocities versus applied signal frequency from 1 kHz to 80 MHz. Simulations indicate differences in the DEP force exerted on each particle according to chain position. Simulations and experiments show excellent qualitative agreement; chains with more particles experienced a decrease in the DEP response for both polystyrene beads and RBCs. These results advance understanding of the extent that induced dipole polarizations with multiple particle chains affect observed behaviors in electrokinetic cellular diagnostic systems. PMID:24658965

Moncada-Hernandez, Hector; Nagler, Eliot; Minerick, Adrienne R

2014-07-01

69

The effect of enoxacin on osteoclastogenesis and reduction of titanium particle-induced osteolysis via suppression of JNK signaling pathway.  

PubMed

The aim of this study was to assess the effect of enoxacin on osteoclastogenesis and titanium particle-induced osteolysis. Wear particles liberated from the surface of prostheses are associated with aseptic prosthetic loosening. It is well established that wear particles induce inflammation, and that extensive osteoclastogenesis plays a critical role in peri-implant osteolysis and subsequent prosthetic loosening. Therefore, inhibiting extensive osteoclast formation and bone resorption could be a potential therapeutic target to prevent prosthetic loosening. In this study, we demonstrated that enoxacin, a fluoroquinolone antibiotic, exerts potent inhibitory effects on titanium particle-induced osteolysis in a mouse calvarial model. Interestingly, the number of mature osteoclasts decreased after treatment with enoxacin in vivo, suggesting that osteoclast formation might be inhibited by enoxacin. We then performed in vitro studies to confirm our hypothesis and revealed the mechanism of action of enoxacin. Enoxacin inhibited osteoclast formation by specifically abrogating RANKL-induced JNK signaling. Collectively, these results suggest that enoxacin, an antibiotic with few side effects that is widely used in clinics, had significant potential for the treatment of particle-induced peri-implant osteolysis and other diseases caused by excessive osteoclast formation and function. PMID:24767789

Liu, Xuqiang; Qu, Xinhua; Wu, Chuanlong; Zhai, Zanjing; Tian, Bo; Li, Haowei; Ouyang, Zhengxiao; Xu, Xinchen; Wang, Wengang; Fan, Qiming; Tang, Tingting; Qin, An; Dai, Kerong

2014-07-01

70

Diesel exhaust particles induce the over expression of tumor necrosis factor-alpha (TNF-alpha) gene in alvelor machrophage and failed to induce apoptosis through activation of nuclear factor-kappaB (NF-kappaB)  

EPA Science Inventory

Exposure to particulate matter (PM2.5-10), including diesel exhaust particles (DEP) has been reported to induce lung injury and exacerbation of asthma and chronic obstructive pulmonary disease. Alveolar macrophages play a major role in the lung's response to inhaled particles and...

71

Single particle characterization of iron-induced pore-forming alpha-synuclein oligomers.  

PubMed

Aggregation of alpha-synuclein is a key event in several neurodegenerative diseases, including Parkinson disease. Recent findings suggest that oligomers represent the principal toxic aggregate species. Using confocal single-molecule fluorescence techniques, such as scanning for intensely fluorescent targets (SIFT) and atomic force microscopy, we monitored alpha-synuclein oligomer formation at the single particle level. Organic solvents were used to trigger aggregation, which resulted in small oligomers ("intermediate I"). Under these conditions, Fe(3+) at low micromolar concentrations dramatically increased aggregation and induced formation of larger oligomers ("intermediate II"). Both oligomer species were on-pathway to amyloid fibrils and could seed amyloid formation. Notably, only Fe(3+)-induced oligomers were SDS-resistant and could form ion-permeable pores in a planar lipid bilayer, which were inhibited by the oligomer-specific A11 antibody. Moreover, baicalein and N'-benzylidene-benzohydrazide derivatives inhibited oligomer formation. Baicalein also inhibited alpha-synuclein-dependent toxicity in neuronal cells. Our results may provide a potential disease mechanism regarding the role of ferric iron and of toxic oligomer species in Parkinson diseases. Moreover, scanning for intensely fluorescent targets allows high throughput screening for aggregation inhibitors and may provide new approaches for drug development and therapy. PMID:18258594

Kostka, Marcus; Högen, Tobias; Danzer, Karin M; Levin, Johannes; Habeck, Matthias; Wirth, Andreas; Wagner, Richard; Glabe, Charles G; Finger, Sabine; Heinzelmann, Udo; Garidel, Patrick; Duan, Wenzhen; Ross, Christopher A; Kretzschmar, Hans; Giese, Armin

2008-04-18

72

Dielectric response of particles in flowing media: The effect of shear-induced rotation on the variation in particle polarizability  

NASA Astrophysics Data System (ADS)

When particles in liquid suspensions flow through channels and pipes in a laminar fashion, the resulting parabolic velocity profile gives rise to shear, which induces the particles to rotate. If flowing suspensions containing dielectric particles are immersed in an external electric field, the anisotropic polarization induced in rotating nonspherical particles will vary with the orientation of the particle with respect to the external field; what results is an uncertainty in experimental measurements that involve particle polarization. The present study establishes the limits of this uncertainty and shows that departure from spherical symmetry in individual particles can lead to a significant overlap in measurements attempting to discriminate between particle subpopulations in suspensions. For example, the uncertainty in signal amplitude for a population of activated T-lymphocytes can be as high as 20%. Such concerns arise in applications like field-flow fractionation, dielectrophoretic sorting of particles, flow impedance measurements and cytometry, and, most recently, isodielectric separation, all of which are used to separate particles in a flow based on their dielectric response. This paper considers axisymmetric particles as the first departure from the approximation of spherical symmetry, shows how to calculate an estimate of the size of the population overlap, and suggests possible strategies to minimize it.

Nikolic-Jaric, Marija; Ferrier, Graham A.; Thomson, Douglas J.; Bridges, Greg E.; Freeman, Mark R.

2011-07-01

73

Fully biodegradable and cationic poly(amino oxalate) particles for the treatment of acetaminophen-induced acute liver failure.  

PubMed

Acute inflammatory diseases are one of major causes of death in the world and there is great need for developing drug delivery systems that can target drugs to macrophages and enhance their therapeutic efficacy. Poly(amino oxalate) (PAOX) is a new family of fully biodegradable polymer that possesses tertiary amine groups in its backbone and has rapid hydrolytic degradation. In this study, we developed PAOX particles as drug delivery systems for treating acute liver failure (ALF) by taking the advantages of the natural propensity of particulate drug delivery systems to localize to the mononuclear phagocyte system, particularly to liver macrophages. PAOX particles showed a fast drug release kinetics and excellent biocompatibility in vitro and in vivo. A majority of PAOX particles were accumulated in liver, providing a rational strategy for effective treatment of ALF. A mouse model of acetaminophen (APAP)-induced ALF was used to evaluate the potential of PAOX particles using pentoxifylline (PTX) as a model drug. Treatment of PTX-loaded PAOX particles significantly reduced the activity of alanine transaminase (ALT) and inhibited hepatic cell damages in APAP-intoxicated mice. The high therapeutic efficacy of PTX-loaded PAOX particles for ALF treatment may be attributed to the unique properties of PAOX particles, which can target passively liver, stimulate cellular uptake and trigger a colloid osmotic disruption of the phagosome to release encapsulated PTX into the cytosol. Taken together, we believe that PAOX particles are a promising drug delivery candidate for the treatment of acute inflammatory diseases. PMID:22664461

Kim, Hyungmin; Kim, Yerang; Guk, Kyeonghye; Yoo, Donghyuck; Lim, Hyungsuk; Kang, Gilson; Lee, Dongwon

2012-09-15

74

Oral immunization of rabbits with VP60 particles confers protection against rabbit hemorrhagic disease.  

PubMed

Rabbit hemorrhagic disease virus (RHDV) causes more than 90% mortality in adult rabbits. In this study, the cDNA of the VP60 coding sequence of RHDV was cloned under the control of the polyhedrin and p10 promoters of baculovirus to be expressed in insect cells. The expression of RHDV VP60 under the control of the p10 promoter was 5-10 times higher than using the polyhedrin promoter. The p10-derived VP60 was able to assemble into virus-like particles (VLPs). RHDV VLPs were successfully used to protect rabbits against the disease even at doses as low as 0.5 micrograms when injected intramuscularly or subcutaneously. The ability to elicit an immune response was independent of the adjuvant or the route of immunization. Remarkably, oral administration of RHDV VLPs efficiently induced protecting antibodies to RHD at doses as low as 3 micrograms. The use of binary ethylenimine for the stabilization of the VLPs was decisive for eliciting a good oral immunity. This report demonstrates the potential use of these procapsids in obtaining RHD oral vaccines and opens the door to the use of these capsids for the prevention of the disease in wild animals. Therefore, a new, and potentially important application of recombinant VLPs in the induction of protective immunity by the oral route is foreseen. PMID:8856024

Plana-Duran, J; Bastons, M; Rodriguez, M J; Climent, I; Cortés, E; Vela, C; Casal, I

1996-01-01

75

Overview of Virus-induced Airway Disease  

Microsoft Academic Search

Acute exacerbations of asthma and chronic obstructive pulmonary disease (COPD) are the major cause of morbidity, mortality, and health costs of both diseases. Currently available treatments are poorly effective in both acute treatment of and prevention of acute exacerbations. New treatments for intervention and prophylaxis are therefore required; to facilitate their development, we must understand the causes and mechanisms of

Sebastian L. Johnston

2005-01-01

76

Particles induce apical plasma membrane enlargement in epithelial lung cell line depending on particle surface area dose  

Microsoft Academic Search

BACKGROUND: Airborne particles entering the respiratory tract may interact with the apical plasma membrane (APM) of epithelial cells and enter them. Differences in the entering mechanisms of fine (between 0.1 ?m and 2.5 ?m) and ultrafine ( ? 0.1 ?m) particles may be associated with different effects on the APM. Therefore, we studied particle-induced changes in APM surface area in

Christina Brandenberger; Barbara Rothen-Rutishauser; Fabian Blank; Peter Gehr; Christian Mühlfeld

2009-01-01

77

A compilation of charged-particle induced thermonuclear reaction rates  

NASA Astrophysics Data System (ADS)

Low-energy cross section data for 86 charged-particle induced reactions involving light (1 <=Z <=14), mostly stable, nuclei are compiled. The corresponding Maxwellian-averaged thermonuclear reaction rates of relevance in astrophysical plasmas at temperatures in the range from 106 K to 1010 K are calculated. These evaluations assume either that the target nuclei are in their ground state, or that the target states are thermally populated following a Maxwell-Boltzmann distribution, except in some cases involving isomeric states. Adopted values complemented with lower and upper limits of the rates are presented in tabular form. Analytical approximations to the adopted rates, as well as to the inverse/direct rate ratios, are provided.

Angulo, C.; Arnould, M.; Rayet, M.; Descouvemont, P.; Baye, D.; Leclercq-Willain, C.; Coc, A.; Barhoumi, S.; Aguer, P.; Rolfs, C.; Kunz, R.; Hammer, J. W.; Mayer, A.; Paradellis, T.; Kossionides, S.; Chronidou, C.; Spyrou, K.; degl'Innocenti, S.; Fiorentini, G.; Ricci, B.; Zavatarelli, S.; Providencia, C.; Wolters, H.; Soares, J.; Grama, C.; Rahighi, J.; Shotter, A.; Lamehi Rachti, M.

1999-08-01

78

Neuroinflammation and Neurodegeneration in Overnutrition-induced Diseases  

PubMed Central

Overnutrition-induced diseases such as obesity and type-2 diabetes involve neural dysregulation of metabolic physiology. Recently, interdisciplinary research in neuroscience and immunology has linked overnutrition to a non-classical onset of inflammation in the brain, and particularly the hypothalamus. This neuroinflammation impairs central regulatory pathways of energy balance and nutrient metabolism, and leads to obesity, diabetes and cardiovascular complications. This review describes recent findings showing the roles of overnutrition-induced hypothalamic inflammation in neurodegeneration and defective adult neurogenesis, as well as impaired neural stem cell regeneration, and its relevance to obesity and related diseases. Also, commonalities in terms of neuroinflammation between neurodegenerative diseases and overnutrition-induced metabolic diseases are discussed. Targeting neuroinflammation and neurodegeneration will provide promising approaches to treating obesity and other overntrution-related diseases.

Cai, Dongsheng

2013-01-01

79

Schisantherin A suppresses osteoclast formation and wear particle-induced osteolysis via modulating RANKL signaling pathways.  

PubMed

Receptor activator of NF-?B ligand (RANKL) plays critical role in osteoclastogenesis. Targeting RANKL signaling pathways has been a promising strategy for treating osteoclast related bone diseases such as osteoporosis and aseptic prosthetic loosening. Schisantherin A (SA), a dibenzocyclooctadiene lignan isolated from the fruit of Schisandra sphenanthera, has been used as an antitussive, tonic, and sedative agent, but its effect on osteoclasts has been hitherto unknown. In the present study, SA was found to inhibit RANKL-induced osteoclast formation and bone resorption. The osteoclastic specific marker genes induced by RANKL including c-Src, SA inhibited OSCAR, cathepsin K and TRAP in a dose dependent manner. Further signal transduction studies revealed that SA down-regulate RANKL-induced nuclear factor-kappaB (NF-?B) signaling activation by suppressing the phosphorylation and degradation of I?B?, and subsequently preventing the NF-?B transcriptional activity. Moreover, SA also decreased the RANKL-induced MAPKs signaling pathway, including JNK and ERK1/2 posphorylation while had no obvious effects on p38 activation. Finally, SA suppressed the NF-?B and MAPKs subsequent gene expression of NFATc1 and c-Fos. In vivo studies, SA inhibited osteoclast function and exhibited bone protection effect in wear-particle-induced bone erosion model. Taken together, SA could attenuate osteoclast formation and wear particle-induced osteolysis by mediating RANKL signaling pathways. These data indicated that SA is a promising therapeutic natural compound for the treatment of osteoclast-related prosthesis loosening. PMID:24845381

He, Yi; Zhang, Qing; Shen, Yi; Chen, Xia; Zhou, Feng; Peng, Dan

2014-07-01

80

Interferon Inducible Chemokines Correlate with Disease Severity in Systemic Sclerosis  

PubMed Central

Objective To measure interferon (IFN) inducible chemokines in plasma of patients with systemic sclerosis (SSc) and investigate their correlation with disease severity. Methods We examined the correlation of IFN-inducible chemokines, IFN?-inducible protein-10 (IP-10/CXCL10), IFN-inducible T cell alpha chemoattractant (I-TAC/CXCL11), and monocyte chemoattractant protein-1 (MCP-1/CCL2) with the IFN gene expression signature. We generated an IFN-inducible chemokine score with the correlated chemokines, IP-10 and I-TAC and compared it in 266 SSc patients enrolled in the GENISOS cohort to that of 97 matched controls. Subsequently, the correlation between the baseline IFN-inducible chemokine score and markers of disease severity was assessed. Finally, the course of IFN-inducible chemokine score over time was examined. Results The plasma IFN-inducible chemokine score correlated with the IFN gene expression signature and this score was higher in SSc patients. It also was associated with the absence of anti–RNA polymerase III antibodies, presence of anti–U1 ribonucleoprotein antibodies (RNP), but not with disease duration, type, or other autoantibodies. The chemokine scores correlated with concomitantly obtained muscle, skin and lung components of the Medsger Severity Index, as well as, FVC, DLco, creatine kinase. Its association with disease severity was independent of anti-RNP or other potential confounders (age, gender, ethnicity, disease duration, and treatment with immunosuppressive agents). Finally, there was not a significant change in the IFN-inducible chemokine score over time. Conclusions The IFN-inducible chemokine score is a stable serological marker of more severe subtype of SSc and may be useful for risk stratification regardless of disease type or duration.

Liu, Xiaochun; Mayes, Maureen D.; Tan, Filemon K.; Wu, Minghua; Reveille, John D.; Harper, Brock E.; Draeger, Hilda T.; Gonzalez, Emilio B.; Assassi, Shervin

2013-01-01

81

Induced pluripotent stem cell modeling of complex genetic diseases  

PubMed Central

The study of complex disease genetics by genome-wide association studies (GWAS) has led to hundreds of genomic loci associated with disease traits in humans. However, the functional consequences of most loci are largely undefined. We discuss here the potential for human induced pluripotent stem (iPS) cells to bridge the gap between genetic variant and mechanisms of complex disease. We also highlight specific diseases and the roadblocks that must be overcome before iPS cell technology can be widely adopted for complex disease modeling.

Hinson, J. Travis; Nakamura, Kenta; Wu, Sean M.

2012-01-01

82

Contact nucleation of ice induced by biological aerosol particles  

NASA Astrophysics Data System (ADS)

The contact freezing of supercooled water droplets is one of the potentially important and the least understood heterogeneous mechanism of ice formation in tropospheric clouds. On the time scales of cloud lifetime the freezing of supercooled water droplets via contact mechanism may occur at higher temperature compared to the same IN immersed in the droplet. Recently we have developed an experimental method allowing for quantification of the freezing probability on a single droplet-particle collision event [1]. In the previous experimental studies with mineral dust (kaolinite, illite, feldspar, and hematite) we have been able to show that the rate of freezing at a given temperature is governed by the rate of droplet - particle collisions, and by the properties of the contact ice nuclei: its size, morphology and composition [1, 2]. In this contribution, we focus on the contact freezing efficiency of biological ice nuclei. We demonstrate that the contact freezing efficiency of Snomax (freeze-dried fragments of Pseudomonas syringae bacteria) follows very similar pattern observed in immersion freezing experiments, indicating that the INA-protein identified as the ice nucleation agent in the immersion freezing mode is also responsible for initiation of contact freezing. The same similarity is observed for contact freezing induced by semi-dry residual particles of birch pollen washing water, providing an evidence for the importance of organic macromolecules of biological origin for nucleation of atmospheric ice. Finally, our experiments show that mixing the birch pollen washing water with mineral dust (illite) significantly increases the IN efficiency of mineral dust and extends the temperature range of its IN activity. These findings suggest a possible route of multiplication of the effect of biological IN beyond observed atmospheric concentrations of pollen grains. [1] - Hoffmann, N., Kiselev, A., Rzesanke, D., Duft, D., and Leisner, T.: Experimental quantification of contact freezing in an electrodynamic balance Atmos. Meas. Tech., 6, 2373-2382, 2013. [2] - Hoffmann, N., Duft, D., Kiselev, A., and Leisner, T.: Contact freezing efficiency of mineral dust aerosols studied in an electrodynamic balance: quantitative size and temperature dependence for illite particles, Faraday Discuss., 2013.

Kiselev, Alexei; Hoffmann, Nadine; Schaefer, Manfred; Duft, Denis; Leisner, Thomas

2014-05-01

83

Ambient air pollution particles and the acute exacerbation of chronic obstructive pulmonary disease  

EPA Science Inventory

Investigation has repeatedly demonstrated an association between exposure to ambient air pollution particles and numerous indices of human morbidity and mortality. Individuals with chronic obstructive pulmonary disease (COPD) are among those with an increased sensitivity to air p...

84

Excitation of high-n toroidicity-induced shear Alfven eigenmodes by energetic particles and fusion alpha particles in tokamaks  

SciTech Connect

The stability of high-n toroidicity-induced shear Alfven eigenmodes (TAE) in the presence of fusion alpha particles or energetic ions in tokamaks is investigated. The TAE modes are discrete in nature and thus can easily tap the free energy associated with energetic particle pressure gradient through wave particle resonant interaction. A quadratic form is derived for the high-n TAE modes using gyro-kinetic equation. The kinetic effects of energetic particles are calculated perturbatively using the ideal MHD solution as the lowest order eigenfunction. The finite Larmor radius (FLR) effects and the finite drift orbit width (FDW) effects are included for both circulating and trapped energetic particles. It is shown that, for circulating particles, FLR and FDW effects have two opposite influences on the stability of the high-n TAE modes. First, they have the usual stabilizing effects by reducing the wave particle interaction strength. Second, they also have destabilizing effects by allowing more particles to resonate with the TAE modes. It is found that the growth rate induced by the circulating alpha particles increase linearly with toroidal mode number n for small {kappa}{sub {theta}}{rho}{sub {alpha}}, and decreases as 1/n for {kappa}{sub {theta}}{rho}{sub {alpha}} {much_gt} 1. The maximum growth rate is obtained at {kappa}{sub {theta}}{rho}{sub {alpha}} on the order of unity and is nearly constant for the range of 0.7 < {upsilon}{sub {alpha}}/{upsilon}{sub A} < 2.5. On the other hand, the trapped particle response is dominated by the precessional drift resonance. The bounce resonant contribution is negligible. The growth rate peaks sharply at the value of {kappa}{sub {theta}}{rho}{sub {alpha}} such that the precessional drift resonance occurs for the most energetic trapped particles. The maximum growth rate due to the energetic trapped particles is comparable to that of circulating particles.

Fu, G.Y.; Cheng, C.Z.

1992-07-01

85

Excitation of high-n toroidicity-induced shear Alfven eigenmodes by energetic particles and fusion alpha particles in tokamaks  

SciTech Connect

The stability of high-n toroidicity-induced shear Alfven eigenmodes (TAE) in the presence of fusion alpha particles or energetic ions in tokamaks is investigated. The TAE modes are discrete in nature and thus can easily tap the free energy associated with energetic particle pressure gradient through wave particle resonant interaction. A quadratic form is derived for the high-n TAE modes using gyro-kinetic equation. The kinetic effects of energetic particles are calculated perturbatively using the ideal MHD solution as the lowest order eigenfunction. The finite Larmor radius (FLR) effects and the finite drift orbit width (FDW) effects are included for both circulating and trapped energetic particles. It is shown that, for circulating particles, FLR and FDW effects have two opposite influences on the stability of the high-n TAE modes. First, they have the usual stabilizing effects by reducing the wave particle interaction strength. Second, they also have destabilizing effects by allowing more particles to resonate with the TAE modes. It is found that the growth rate induced by the circulating alpha particles increase linearly with toroidal mode number n for small {kappa}{sub {theta}}{rho}{sub {alpha}}, and decreases as 1/n for {kappa}{sub {theta}}{rho}{sub {alpha}} {much gt} 1. The maximum growth rate is obtained at {kappa}{sub {theta}}{rho}{sub {alpha}} on the order of unity and is nearly constant for the range of 0.7 < {upsilon}{sub {alpha}}/{upsilon}{sub A} < 2.5. On the other hand, the trapped particle response is dominated by the precessional drift resonance. The bounce resonant contribution is negligible. The growth rate peaks sharply at the value of {kappa}{sub {theta}}{rho}{sub {alpha}} such that the precessional drift resonance occurs for the most energetic trapped particles. The maximum growth rate due to the energetic trapped particles is comparable to that of circulating particles.

Fu, G.Y.; Cheng, C.Z.

1992-07-01

86

Noise-induced transport of two coupled particles  

Microsoft Academic Search

We study the motion of two harmonically coupled particles in a sawtooth potential. The particles are subject to temporally correlated multiplicative noise. The stationary current is calculated in an expansion about the limit of rigid coupling. For two coupled particles a driving mechanism occurs which is different from the one occurring in the case of a single particle. In particular

Stefan Klumpp; Andreas Mielke; Christian Wald

2001-01-01

87

Virus-like particles associated with banana bunchy top disease contain small single-stranded DNA  

Microsoft Academic Search

Virus-like particles were purified from banana plants with banana bunchy top disease. These particles were isometric with a diameter of 18 to 20 nm and a density of 1.28 to 1-30 g\\/ml in caesium sulphate. Associated with these particles were an ssDNA of about 1 kb and one major protein of Mr 20100. DsDNA was synthe- sized from nucleic acid

Robert M. Harding; Thomas M. Burns; James L. Dale

1991-01-01

88

A high school gym-induced disease  

Microsoft Academic Search

Physical exercise may induce upper and lower airway symptoms such as rhinitis and asthma. Rhinitis symptoms are often neglected although runny nose and nasal congestion may interfere with performance of the affected individual. A detailed history regarding locality and time of symptoms is of most significance for taking the appropriate diagnostic measures and identifying, as in this case, an uncommon

C S Seitz; E B Bröcker; A Trautmann

2008-01-01

89

Nephrolithiasis-induced end stage renal disease  

PubMed Central

Introduction: Nephrolithiasis still remains a too frequent and underappreciated cause of end stage renal disease (ESRD). Methods and patients: Of the entire cohort of 7128 consecutive patients who started maintenance dialysis in our nephrology department between January 1992 and December 2006, a total of 45 patients (26 women, 19 men) had renal stone disease as the cause of ESRD. The type of nephrolithiasis was determined in 45 cases and etiology in 42. The treatment and evolution of stone disease and patient’s survival were studied. Results: The overall proportion of nephrolithiasis related ESRD was 0.63%. The mean age was 48.4 years. Infection stones (struvite) accounted for 40%, calcium stones, 26.67% (primary hyperparathyroidism:15.56%; familial hypercalciuria: 4.44%, unknown etiology: 6.66%), primary hyperoxaluria type 1, 17.78% and uric acid lithiasis in 15.56% of cases. The mean delay of the evolution of the stone renal disease to chronic renal failure was 85.8 months. The feminine gender, obesity and elevated alkaline phosphatases >128 IU/L were significantly correlated with fast evolution of ESRD. The median evolution to ESRD was 12 months. The normal body mass index (BMI), medical treatment of stone and primary hyperoxaluria type 1 were correlated with fast evolution to ESRD. All patients were treated by hemodialysis during a mean evolution of 60 months. Sixteen patients died. The patient's survival rate at 1, 3 and 5 years was 97.6, 92.8 and 69% respectively. Hypocalcemia, cardiopathy and normal calcium-phosphate product were significantly correlated with lower survival rate. Conclusion: Severe forms of nephrolithiasis remain an underestimated cause of ESRD. These findings highlight the crucial importance of accurate stone analysis and metabolic evaluation to provide early diagnosis and efficient treatment for conditions leading to ESRD.

Ounissi, M; Gargueh, T; Mahfoudhi, M; Boubaker, K; Hedri, H; Goucha, R; Abderrahim, E; Ben Hamida, F; Ben Abdallah, T; El Younsi, F; Ben Maiz, H; Kheder, A

2010-01-01

90

Thermodynamics inducing massive particles' tunneling and cosmic censorship  

NASA Astrophysics Data System (ADS)

By calculating the change of entropy, we prove that the first law of black hole thermodynamics leads to the tunneling probability of massive particles through the horizon, including the tunneling probability of massive charged particles from the Reissner-Nordström black hole and the Kerr-Newman black hole. Novelly, we find the trajectories of massive particles are close to that of massless particles near the horizon, although the trajectories of massive charged particles may be affected by electromagnetic forces. We show that Hawking radiation as massive particles tunneling does not lead to violation of the weak cosmic-censorship conjecture.

Zhang, Baocheng; Cai, Qing-Yu; Zhan, Ming-Sheng

2010-08-01

91

Theory of mode-induced beam-particle loss in tokamaks  

SciTech Connect

Large-amplitude rotating magnetohydrodynamic modes have been observed to induce significant high-energy-beam particle loss during high-power perpendicular neutral-beam injection on PDX. A Hamiltonian formalism for drift-orbit trajectories in the presence of such modes is used to study induced particle loss analytically and numerically. Results are in good agreement with experiment.

White, R.B.; Goldston, R.J.; McGuire, K.; Boozer, A.H.; Monticello, D.A.; Park, W.

1983-04-01

92

Rapid repair of titanium particle-induced osteolysis is dramatically reduced in aged mice  

Microsoft Academic Search

Aseptic loosening is the most common cause of orthopaedic implant failure. This process is thought to be due to osteolysis induced by implant-derived wear particles. Teitelbaum and colleagues have recently developed a promising murine calvarial model of wear particle-induced osteolysis. However, prior to this study, this model had only been assessed qualitatively. We now report a reproducible, quantitative version of

Scott G. Kaar; Ashraf A. Ragab; Sarah J. Kaye; B. Alper Kilic; Tetsuya Jinno; Victor M. Goldberg; Yanming Bi; Matthew C. Stewart; John R. Carter; Edward M. Greenfield

2001-01-01

93

Particle-induced bit errors in high performance fiber optic data links for satellite data management  

Microsoft Academic Search

Experimental test methods and analysis tools are demonstrated to assess particle-induced bit errors on fiber optic link receivers for satellites. Susceptibility to direct ionization from low LET particles is quantified by analyzing proton and helium ion data as a function of particle LET. Existing single event analysis approaches are shown to apply, with appropriate modifications, to the regime of temporally

P. W. Marshall; Cheryl J. Dale; Martin A. Carts; K. A. LaBel

1994-01-01

94

The effect of flow geometry on shear-induced particle segregation and resuspension  

Microsoft Academic Search

In this thesis, we investigate through theory and experiment the influence of the flow geometry on various shear-induced migration phenomena such as particle demixing, viscous resuspension and meniscus accumulation for a suspension of rigid, non-colloidal particles. The major focus of this thesis is the elucidation of a particle flux mechanism that has been ignored in the literature in the theoretical

Arun Ramachandran

2007-01-01

95

Effect of the induced-dipole force on charging rates of aerosol particles  

NASA Astrophysics Data System (ADS)

Natanson's model {Zh. Tekh. Fiz., 30, 573 (1960) [English translation: Sov. Phys. Tech. Phys. 5, 538 (1960)]} for the collection of ions by aerosol particles is modified so that both the Coulomb force and the induced-dipole force are included for the case of attractive aerosol particles. Natanson included the induced-dipole force and the Coulomb force together only for the Coulomb force being repelling. The induced-dipole force increases ion collection rates by about a factor of 2 for the smallest aerosol particles. The results are applicable to the collection of both ions and electrons by noctilucent cloud particles and meteoritic dust in the mesosphere.

Robertson, Scott; Sternovsky, Zoltan

2008-04-01

96

Induced-charge electroosmotic flow around dielectric particles in uniform electric field.  

PubMed

The current research of induced-charge electroosmotic flow (ICEOF) is mostly confined to systems with ideally or fully polarizable surfaces (e.g., metal). However, most materials in nature have various degrees of polarizability, which directly affects the induced charges and subsequently the induced-charge electroosmotic flow. This paper studied the effect of the polarizability of the materials on the ICEOF. An analytical expression of the induced potential on the surface of a dielectric particle in a uniform electrical field was derived. Three-dimensional transient numerical simulations of the ICEOF and the motion of dielectric particles were performed to study the effect of the polarizability. Simulation results show that the transportation of the dielectric particle in a microchannel is not affected by the polarizability of the particle; however, the interaction of two dielectric particles is sensitive to the polarizability of the particles. PMID:24034219

Zhang, Fang; Li, Dongqing

2013-11-15

97

Alpha-particle-induced soft errors in dynamic memories  

Microsoft Academic Search

A new physical soft error mechanism in dynamic RAM's and CCD's is the upset of stored data by the passage of alpha particles through the memory array area. The alpha particles are emitted by the radioactive decay of uranium and thorium which are present in parts-per-million levels in packaging materials. When an alpha particle penetrates the die surface, it can

T. C. May; M. H. Woods

1979-01-01

98

Toxin-Induced Models of Parkinson's Disease  

PubMed Central

Summary: Parkinson's disease (PD) is a common neurodegenerative disease that appears essentially as a sporadic condition. It results mainly from the death of dopaminergic neurons in the substantia nigra. PD etiology remains mysterious, whereas its pathogenesis begins to be understood as a multifactorial cascade of deleterious factors. Most insights into PD pathogenesis come from investigations performed in experimental models of PD, especially those produced by neurotoxins. Although a host of natural and synthetic molecules do exert deleterious effects on dopaminergic neurons, only a handful are used in living laboratory animals to recapitulate some of the hallmarks of PD. In this review, we discuss what we believe are the four most popular parkinsonian neurotoxins, namely 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), rotenone, and paraquat. The main goal is to provide an updated summary of the main characteristics of each of these four neurotoxins. However, we also try to provide the reader with an idea about the various strengths and the weaknesses of these neurotoxic models.

Bove, Jordi; Prou, Delphine; Perier, Celine; Przedborski, Serge

2005-01-01

99

Dynamics of magnetic particles near a surface: Model and experiments on field-induced disaggregation  

NASA Astrophysics Data System (ADS)

Magnetic particles are widely used in biological research and bioanalytical applications. As the corresponding tools are progressively being miniaturized and integrated, the understanding of particle dynamics and the control of particles down to the level of single particles become important. Here, we describe a numerical model to simulate the dynamic behavior of ensembles of magnetic particles, taking account of magnetic interparticle interactions, interactions with the liquid medium and solid surfaces, as well as thermal diffusive motion of the particles. The model is verified using experimental data of magnetic field-induced disaggregation of magnetic particle clusters near a physical surface, wherein the magnetic field properties, particle size, cluster size, and cluster geometry were varied. Furthermore, the model clarifies how the cluster configuration, cluster alignment, magnitude of the field gradient, and the field repetition rate play a role in the particle disaggregation process. The simulation model will be very useful for further in silico studies on magnetic particle dynamics in biotechnological tools.

van Reenen, A.; Gao, Y.; de Jong, A. M.; Hulsen, M. A.; den Toonder, J. M. J.; Prins, M. W. J.

2014-04-01

100

Induced pluripotent stem cells in the study of neurological diseases  

PubMed Central

Five years after their initial derivation from mouse somatic cells, induced pluripotent stem (iPS) cells are an important tool for the study of neurological diseases. By offering an unlimited source of patient-specific disease-relevant neuronal and glial cells, iPS cell-based disease models hold enormous promise for identification of disease mechanisms, discovery of molecular targets and development of phenotypic screens for drug discovery. The present review focuses on the recent advancements in modeling neurological disorders, including the demonstration of disease-specific phenotypes in iPS cell-derived neurons generated from patients with spinal muscular atrophy, familial dysautonomia, Rett syndrome, schizophrenia and Parkinson disease. The ability of this approach to detect treatment effects from known therapeutic compounds has also been demonstrated, providing proof of principle for the use of iPS cell-derived cells in drug discovery.

2011-01-01

101

Thermally relativistic flows induced by gravitational-force-free particle motion in curved spacetime  

NASA Astrophysics Data System (ADS)

Thermally relativistic flows in the early Universe can be characterized by the emergence of flows induced by gravitational-force-free particle motion in curved spacetime as well as induced by the gravitational force. In this paper, thermally relativistic flows induced by gravitational-force-free particle motion in curved spacetime are discussed on the basis of the general relativistic Boltzmann equation. As an object of analysis, we consider the flow from the static state inside the Schwarzschild radius of a thermally relativistic stuffed black hole induced by such motion. Analytical results obtained using the collisionless, nongravitational general relativistic Boltzmann equation reveal that the initial cluster is induced by gravitational-force-free particle motion. Numerical results obtained using the nongravitational general relativistic Anderson-Witting model confirm the presence of an initial cluster inside the thermally relativistic stuffed black hole, which is induced by gravitational-force-free particle motion.

Yano, Ryosuke; Suzuki, Kojiro; Kuroda, Hisayasu

2009-12-01

102

Thermally relativistic flows induced by gravitational-force-free particle motion in curved spacetime  

SciTech Connect

Thermally relativistic flows in the early Universe can be characterized by the emergence of flows induced by gravitational-force-free particle motion in curved spacetime as well as induced by the gravitational force. In this paper, thermally relativistic flows induced by gravitational-force-free particle motion in curved spacetime are discussed on the basis of the general relativistic Boltzmann equation. As an object of analysis, we consider the flow from the static state inside the Schwarzschild radius of a thermally relativistic stuffed black hole induced by such motion. Analytical results obtained using the collisionless, nongravitational general relativistic Boltzmann equation reveal that the initial cluster is induced by gravitational-force-free particle motion. Numerical results obtained using the nongravitational general relativistic Anderson-Witting model confirm the presence of an initial cluster inside the thermally relativistic stuffed black hole, which is induced by gravitational-force-free particle motion.

Yano, Ryosuke; Suzuki, Kojiro; Kuroda, Hisayasu [Department of Advanced Energy, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Department of Advanced Energy, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Department of Information Technology, University of Ehime, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577 (Japan)

2009-12-15

103

Toxicogenomic analysis of the particle dose- and size-response relationship of silica particles-induced toxicity in mice.  

PubMed

This study investigated the relationship between particle size and toxicity of silica particles (SP) with diameters of 30, 70, and 300 nm, which is essential to the safe design and application of SP. Data obtained from histopathological examinations suggested that SP of these sizes can all induce acute inflammation in the liver. In vivo imaging showed that intravenously administrated SP are mainly present in the liver, spleen and intestinal tract. Interestingly, in gene expression analysis, the cellular response pathways activated in the liver are predominantly conserved independently of particle dose when the same size SP are administered or are conserved independently of particle size, surface area and particle number when nano- or submicro-sized SP are administered at their toxic doses. Meanwhile, integrated analysis of transcriptomics, previous metabonomics and conventional toxicological results support the view that SP can result in inflammatory and oxidative stress, generate mitochondrial dysfunction, and eventually cause hepatocyte necrosis by neutrophil-mediated liver injury. PMID:23221170

Lu, Xiaoyan; Jin, Tingting; Jin, Yachao; Wu, Leihong; Hu, Bin; Tian, Yu; Fan, Xiaohui

2013-01-11

104

Toxicogenomic analysis of the particle dose- and size-response relationship of silica particles-induced toxicity in mice  

NASA Astrophysics Data System (ADS)

This study investigated the relationship between particle size and toxicity of silica particles (SP) with diameters of 30, 70, and 300 nm, which is essential to the safe design and application of SP. Data obtained from histopathological examinations suggested that SP of these sizes can all induce acute inflammation in the liver. In vivo imaging showed that intravenously administrated SP are mainly present in the liver, spleen and intestinal tract. Interestingly, in gene expression analysis, the cellular response pathways activated in the liver are predominantly conserved independently of particle dose when the same size SP are administered or are conserved independently of particle size, surface area and particle number when nano- or submicro-sized SP are administered at their toxic doses. Meanwhile, integrated analysis of transcriptomics, previous metabonomics and conventional toxicological results support the view that SP can result in inflammatory and oxidative stress, generate mitochondrial dysfunction, and eventually cause hepatocyte necrosis by neutrophil-mediated liver injury.

Lu, Xiaoyan; Jin, Tingting; Jin, Yachao; Wu, Leihong; Hu, Bin; Tian, Yu; Fan, Xiaohui

2013-01-01

105

Single particle detection of Abeta aggregates associated with Alzheimer's disease.  

PubMed

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. Today, AD can be diagnosed with certainty only post-mortem, by histopathologic staining of Abeta plaques and neurofibrillary tangles in brain tissue sections. We have developed an ultra-sensitive assay potentially suitable for early and non-invasive diagnosis of AD. This highly specific and sensitive assay uses fluorescence correlation spectroscopy (FCS) and is sensitive enough to detect even single aggregates in body fluids of AD patients. First results show a clear distinction between AD diseased people and non-demented controls by analysing cerebrospinal fluids (CSF) by confocal scanning of surface captured Abeta aggregates and subsequent two-dimensional fluorescence intensity distribution analysis. PMID:17963690

Funke, Susanne Aileen; Birkmann, Eva; Henke, Franziska; Görtz, Philipp; Lange-Asschenfeldt, Christian; Riesner, Detlev; Willbold, Dieter

2007-12-28

106

Severe immunodeficiency disease induced by a defective murine leukaemia virus  

Microsoft Academic Search

DIFFERENT classes of retroviruses have been shown to induce immunodeficiency diseases in various animal species1. These animal models may provide an insight into our understanding of AIDS1-3 but, with the exception of one strain of feline leukaemia virus4, the determinants of pathogenicity have not yet been mapped to these viral genomes. The immunodeficiency-inducing feline leukaemia virus is replication-defective4, harbouring the

Douglas C. Aziz; Zaher Hanna; Paul Jolicoeur

1989-01-01

107

Oxygen sensing, hypoxia-inducible factors, and disease pathophysiology.  

PubMed

Hypoxia-inducible factors (HIFs) are transcriptional activators that function as master regulators of oxygen homeostasis, which is disrupted in disorders affecting the circulatory system and in cancer. The role of HIFs in these diseases has been elucidated by clinical studies and by analyses of mouse models. HIFs play a protective role in the pathophysiology of myocardial ischemia due to coronary artery disease, limb ischemia due to peripheral arterial disease, pressure-overload heart failure, wound healing, and chronic rejection of organ transplants. In contrast, HIFs contribute to the pathogenesis of pulmonary arterial hypertension, systemic hypertension associated with sleep apnea, ocular neovascularization, hereditary erythrocytosis, and cancer. PMID:23937437

Semenza, Gregg L

2014-01-01

108

Biological effects induced by nanosilver particles: in vivo study.  

PubMed

Nanosilver particles and microsilver particles were implanted into a rat's back muscle. The pathology and the local biocompatibility were observed and compared at days 7, 14, 30, 90 and 180 after implantation. A good biological effect was observed on days 7 and 14, both in rats treated with nanosilver particles and in rats treated with microsilver particles. A bad biological effect was observed at day 30, and the nanosilver-treated rats had more serious inflammation than the microsilver-treated rats. PMID:18458456

Chen, Dandan; Xi, Tingfei; Bai, Jing

2007-09-01

109

Passing particle toroidal precession induced by electric field in a tokamak  

NASA Astrophysics Data System (ADS)

Characteristics of a rotation of passing particles in a tokamak with radial electric field are calculated. The expression for time-averaged toroidal velocity of the passing particle induced by the electric field is derived. The electric-field-induced additive to the toroidal velocity of the passing particle appears to be much smaller than the velocity of the electric drift calculated for the poloidal magnetic field typical for the trapped particle. This quantity can even have the different sign depending on the azimuthal position of the particle starting point. The unified approach for the calculation of the bounce period and of the time-averaged toroidal velocity of both trapped and passing particles in the whole volume of plasma column is presented. The results are obtained analytically and are confirmed by 3D numerical calculations of the trajectories of charged particles.

Andreev, V. V.; Ilgisonis, V. I.; Sorokina, E. A.

2013-12-01

110

Passing particle toroidal precession induced by electric field in a tokamak  

SciTech Connect

Characteristics of a rotation of passing particles in a tokamak with radial electric field are calculated. The expression for time-averaged toroidal velocity of the passing particle induced by the electric field is derived. The electric-field-induced additive to the toroidal velocity of the passing particle appears to be much smaller than the velocity of the electric drift calculated for the poloidal magnetic field typical for the trapped particle. This quantity can even have the different sign depending on the azimuthal position of the particle starting point. The unified approach for the calculation of the bounce period and of the time-averaged toroidal velocity of both trapped and passing particles in the whole volume of plasma column is presented. The results are obtained analytically and are confirmed by 3D numerical calculations of the trajectories of charged particles.

Andreev, V. V. [Peoples' Friendship University of Russia, Ordzhonikidze St. 3, Moscow 117198 (Russian Federation)] [Peoples' Friendship University of Russia, Ordzhonikidze St. 3, Moscow 117198 (Russian Federation); Ilgisonis, V. I.; Sorokina, E. A. [Peoples' Friendship University of Russia, Ordzhonikidze St. 3, Moscow 117198 (Russian Federation) [Peoples' Friendship University of Russia, Ordzhonikidze St. 3, Moscow 117198 (Russian Federation); NRC “Kurchatov Institute”, Kurchatov Sq. 1, Moscow 123182 (Russian Federation)

2013-12-15

111

ULTRAFINE CARBON PARTICLES INDUCE IL-8 EXPRESSION IN HUMAN AIRWAY EPITHELIAL CELLS THROUGH A POST-TRANSCRIPTIONAL MECHANISM  

EPA Science Inventory

Ultrafine carbon particles induce IL-8 expression in human airway epithelial cells through a post-transcritpional mechanism Epidemiological studies suggest that ultrafine particles contribute to particulate matter (PM) - induced adverse health effects. IL-8 is an i...

112

Particle Trapping at Planet-Induced Gap Edges and Vortices  

NASA Astrophysics Data System (ADS)

We use numerical simulations to perform a systematic study on the dynamics of dust particles in protoplanetary disks under the influence of a planet in disks. Dust particles in viscous disks (representing turbulent regions in disks) and inviscid hydro disks (``dead zone'') have been simulated separately using our newly developed Two-Fluids FARGO and ATHENA+Particle codes. For inviscid 3-D disks, we found that a low mass planet (8 M_earth) open almost unnoticeable gaps in gas which can still lead to significant dust piling up at gap edges. Sharp gap edges carved out by a massive planet are unstable to the formation of vortices, which can efficiently trap particles with a wide range of sizes(at least 4 orders of magnitude in our cases). Thus gaps and vortices in particle disks should be very common if there are planets in the``dead zones''. For viscous disks, the dust features are significantly smoothed out by the parameterized turbulent diffusion, and small dust particles can follow the accreting gas flowing to the inner disk. Thus, the so-called ``dust filtration'' mechanism by the gap edges can differentiate big and small dust particles. MHD simulations are developed to understand the gap opening and particle concentration in realistic turbulent disks.

Zhu, Zhaohuan; Stone, James; Rafikov, Roman; Bai, Xuening; Espaillat, Catherine

2013-07-01

113

Particle-induced circulatory disturbances in transplanted rhesus macaque kidneys  

Microsoft Academic Search

We have demonstrated the presence of crystalline particles in University of Wisconsin (UW) solution used to perfuse rhesus monkey kidney transplants. These particles were visible in obstructed blood vessels and associated with immediate graft thrombosis and necrosis. This occurred in 25.7% of kidneys perfused with UW solution and transplanted into young, unsensitized recipients. Two molecular species of crystals were defined

William J. Hubbard; Anne Hutchings; Devin Eckhoff; Juan Contreras; Martha Wilkins; Francis T. Thomas; Michael Clements; Judith M. Thomas

2003-01-01

114

Charged particle-induced noise in camera systems  

Microsoft Academic Search

When a camera system is operated in a flux of charged particles, it will generate transient signals. The charged particles will impinge on the focal plane array and generate tracks of ionized electron-hole pairs. The charge tracks will diffuse, and some of the charge will be collected as signal and the rest will recombine. Bremsstrahlung radiation will be generated in

Carl Christian Liebe

2001-01-01

115

A small nonhuman primate model for filovirus-induced disease.  

PubMed

Ebolavirus and Marburgvirus are members of the filovirus family and induce a fatal hemorrhagic disease in humans and nonhuman primates with 90% case fatality. To develop a small nonhuman primate model for filovirus disease, common marmosets (Callithrix jacchus) were intramuscularly inoculated with wild type Marburgvirus Musoke or Ebolavirus Zaire. The infection resulted in a systemic fatal disease with clinical and morphological features closely resembling human infection. Animals experienced weight loss, fever, high virus titers in tissue, thrombocytopenia, neutrophilia, high liver transaminases and phosphatases and disseminated intravascular coagulation. Evidence of a severe disseminated viral infection characterized principally by multifocal to coalescing hepatic necrosis was seen in EBOV animals. MARV-infected animals displayed only moderate fibrin deposition in the spleen. Lymphoid necrosis and lymphocytic depletion observed in spleen. These findings provide support for the use of the common marmoset as a small nonhuman primate model for filovirus induced hemorrhagic fever. PMID:21959017

Carrion, Ricardo; Ro, Youngtae; Hoosien, Kareema; Ticer, Anysha; Brasky, Kathy; de la Garza, Melissa; Mansfield, Keith; Patterson, Jean L

2011-11-25

116

Hypoxia and Hypoxia Inducible Factors: Diverse Roles in Liver Diseases  

PubMed Central

Hypoxia has been shown to have a role in the pathogenesis of several forms of liver disease. The Hypoxia Inducible Factors (HIFs) are a family of evolutionarily conserved transcriptional regulators that affect a homeostatic response to low oxygen tension and have been identified as key mediators of angiogenesis, inflammation, and metabolism. In this review, we summarize the evidence for a role of HIFs across a range of hepatic pathophysiology. We describe regulation of the hypoxia inducible factors and review investigations that demonstrate a role for HIFs in the development of liver fibrosis, activation of innate immune pathways, hepatocellular carcinoma, as well as other liver diseases in both human disease as well as murine models.

Nath, Bharath; Szabo, Gyongyi

2011-01-01

117

A small nonhuman primate model for filovirus-induced disease  

PubMed Central

Ebolavirus and Marburgvirus are members of the filovirus family and induce a fatal hemorrhagic disease in humans and nonhuman primates with 90% case fatality. To develop a small nonhuman primate model for filovirus disease, common marmosets (Callithrix jacchus) were intramuscularly inoculated with wild type Marburgvirus Musoke or Ebolavirus Zaire. The infection resulted in a systemic fatal disease with clinical and morphological features closely resembling human infection. Animals experienced weight loss, fever, high virus titers in tissue, thrombocytopenia, neutrophilia, high liver transaminases and phosphatases and disseminated intravascular coagulation. Evidence of a severe disseminated viral infection characterized principally by multifocal to coalescing hepatic necrosis was seen in EBOV animals. MARV-infected animals displayed only moderate fibrin deposition in the spleen. Lymphoid necrosis and lymphocytic depletion observed in spleen. These findings provide support for the use of the common marmoset as a small nonhuman primate model for filovirus induced hemorrhagic fever.

Carrion, Ricardo; Ro, Youngtae; Hoosien, Kareema; Ticer, Anysha; Brasky, Kathy; de la Garza, Melissa; Mansfield, Keith; Patterson, Jean L.

2011-01-01

118

Abundance of surfactant-like particles reflects mucosal integrity in patients with peptic ulcer disease.  

PubMed Central

BACKGROUND: Surfactant-like particles, normal products of the human enterocyte, are released into the lumen and secreted into blood. AIMS: To assess their role as markers for mucosal functional integrity, this study examined their content in biopsy specimens and serum of patients with duodenal ulcer disease, compared with non-diseased control subjects. PATIENTS: Endoscopic biopsy specimens were taken 1-2 cm from areas of active inflammation or ulcer (peptic ulcer patients) or just beyond the duodenal bulb (normals) in 35 consecutive subjects. METHODS: After staining for phospholipid, extracellular and intracellular particles were counted on transmission electron micrographs of coded specimens. Serum was obtained from 24 patients, and densitometry of the 59 kDa band detected on western blot by antiserum against human jejunal particle was measured. RESULTS: Normal duodenum (n = 15) contained more particles (44 (4.7)) particles/block, mean (SD) than active duodenal ulcer (n = 13, 17 (3.9)) or gastritis/duodenitis patients (n = 4, 9 (2.7)). Three patients examined after healing of duodenal ulcers showed abundant particles (n = 3, 67 (2.2)). Similarly, the 59 kDa band was decreased in serum of patients with active peptic ulcer disease (n = 11, 0.25 (0.04) absorbance units) compared with normal patients (n = 10, 0.40 (0.03)) or healed ulcers (n = 3, 0.62 (0.04)). There was good correlation between morphological mucosal particle abundance and particle protein content of serum assayed from the same patients (r = 0.831). These changes were independent of Helicobacter pylori status. CONCLUSION: The mucosal and serum content of surfactant-like particles may reflect general mucosal integrity of the enterocytes from which they are derived. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Eliakim, R; Alpers, D H; Oren, R; Fich, A; DeSchryver-Kecskemeti, K

1996-01-01

119

Developments in virus-like particle-based vaccines for infectious diseases and cancer.  

PubMed

Virus-like particles hold great promise for the development of effective and affordable vaccines. Indeed, virus-like particles are suitable for presentation and efficient delivery of linear as well as conformational antigens to antigen-presenting cells. This will ultimately result in optimal B-cell activation and cross-presentation with both MHC class I and II molecules to prime CD4(+) T-helper as well as CD8(+) cytotoxic T cells. This article provides an update on the development and use of virus-like particles as vaccine approaches for infectious diseases and cancer. PMID:22043956

Buonaguro, Luigi; Tagliamonte, Maria; Tornesello, Maria Lina; Buonaguro, Franco M

2011-11-01

120

Aloe vera Induced Biomimetic Assemblage of Nucleobase into Nanosized Particles  

PubMed Central

Aim Biomimetic nano-assembly formation offers a convenient and bio friendly approach to fabricate complex structures from simple components with sub-nanometer precision. Recently, biomimetic (employing microorganism/plants) synthesis of metal and inorganic materials nano-particles has emerged as a simple and viable strategy. In the present study, we have extended biological synthesis of nano-particles to organic molecules, namely the anticancer agent 5-fluorouracil (5-FU), using Aloe vera leaf extract. Methodology The 5-FU nano- particles synthesized by using Aloe vera leaf extract were characterized by UV, FT-IR and fluorescence spectroscopic techniques. The size and shape of the synthesized nanoparticles were determined by TEM, while crystalline nature of 5-FU particles was established by X-ray diffraction study. The cytotoxic effects of 5-FU nanoparticles were assessed against HT-29 and Caco-2 (human adenocarcinoma colorectal) cell lines. Results Transmission electron microscopy and atomic force microscopic techniques confirmed nano-size of the synthesized particles. Importantly, the nano-assembled 5-FU retained its anticancer action against various cancerous cell lines. Conclusion In the present study, we have explored the potential of biomimetic synthesis of nanoparticles employing organic molecules with the hope that such developments will be helpful to introduce novel nano-particle formulations that will not only be more effective but would also be devoid of nano-particle associated putative toxicity constraints.

Chauhan, Arun; Zubair, Swaleha; Sherwani, Asif; Owais, Mohammad

2012-01-01

121

DIESEL EXHAUST PARTICLES INDUCE ABERRANT ALVEOLAR EPITHELIAL DIRECTED CELL MOVEMENT BY DISRUPTION OF POLARITY MECHANISMS  

EPA Science Inventory

Disruption of the respiratory epithelium contributes to the progression of a variety of respiratory diseases that are aggravated by exposure to air pollutants, specifically traffic-based pollutants such as diesel exhaust particles (DEP). Recognizing that lung repair following inj...

122

Filler particles used in dental biomaterials induce production and release of inflammatory mediators in vitro.  

PubMed

Although dental composites are in extensive use today, little is known about the biological effects of the filler particles. As composite materials are gradually broken down in the aggressive environment of the oral cavity, the filler particles may leak and induce toxic effects on the surrounding tissue and cells. The aim of this study was to elucidate possible adverse biological effects of commonly used dental filler particles; bariumaluminiumsilica (BaAlSi) and bariumaluminiumfluorosilica (BaAlFSi) with mean size of 1 microm. BEAS-2B cells were used as a model system. Particle morphology, mean particle size in solution, and particle surface charge were determined by scanning electron microscopy and Malvern zetasizer technology, respectively. Enzyme-linked immunosorbent assay was used to detect secretion of cytokine and chemokine (IL-8 and IL-6) and quantitative PCR for detection of gene activity. Both types of particle increased the release of IL-6 and IL-8 in a dose-dependent manner. BaAlFSi particles induced a more marked IL-8 response compared to BaAlSi particles, whereas no significant difference was observed for the IL-6 response. Mechanistic studies using specific inhibitors and activators indicated that cyclic AMP-dependent protein kinase A is partly involved in the observed IL-8 response. In conclusion, we consider dental filler particles to have potential to induce adverse biological response in cell cultures. PMID:18759324

Ansteinsson, Vibeke E; Samuelsen, Jan Tore; Dahl, Jon E

2009-04-01

123

Plasma-particle interactions for the quantitative analysis of individual aerosol particles using laser-induced breakdown spectroscopy  

NASA Astrophysics Data System (ADS)

In response to the need for discrete characterization of ambient air fine particles due to the direct relation of particle size and particle composition to human health effects, laser-induced breakdown spectroscopy (LIBS) has been studied in this dissertation to support its development as a real-time aerosol analysis technique capable of measuring particle size and particle composition. In Chapter 1, a literature review and the principles of LIBS are presented in the context of aerosol analysis. The complete experimental facilities are described in Chapter 2. An aerosol generation system was developed to produce well-dispersed aerosolized nanoparticles that served as the calibration source for the LIBS system. The LIBS system consists of a 1064-nm Nd:YAG pulse laser, supporting optics, and an intensified charge-coupled device for plasma emission quantification. The developed LIBS system was successfully deployed as discussed in Chapter 3 for ambient air monitoring (specifically aluminum, magnesium, calcium, and sodium). Mass concentrations were recorded on the order of low parts per trillion and minimum particle sizes about 200 nm. In Chapter 4, issues of plasma homogeneity and signal fluctuations on a shot-to-shot basis were addressed to elucidate optimal laser pulse energy for single shot analysis, thereby identifying a characteristic state of the plasma where signal fluctuations are minimized. The implicit assumption of complete particle vaporization is investigated in detail in Chapter 5, with the determination that silica particles up to 2.1-mum diameters are completely vaporized due to plasma-particle interactions. Finally, the characteristic plasma volumes related to the scheme of particle sizing are determined and analyzed in the context of the analysis of single aerosol particle detection. The outcome of this research yielded an enhanced understanding of single aerosol analysis with the LIBS technique. Important conclusions are that LIBS measurement should be made at the plasma saturation condition, particle sizing should be limited to about 2 mum or less, particle vaporization is driven by plasma-particle interactions, and that real-time ambient air monitoring is feasible with LIBS on time periods as short as 4 minutes.

Carranza, Jorge E.

124

Respiratory failure due to infliximab induced interstitial lung disease.  

PubMed

Although poorly understood, interstitial lung disease has been reported as a possible complication of tumor necrosis factor alpha inhibitors. We report a case of interstitial lung disease in a 64-year-old man with psoriasis 3 weeks after the initiation of infliximab treatment. The patient had received two fortnightly infusions of infliximab following a short course of methotrexate. Thoracic computed tomography showed bilateral ground glass and interstitial infiltrates, while the results of microbiology and immunologic workup were negative. Likewise, bronchoalveolar lavage detected neither typical nor atypical pathogens. Infliximab-induced interstitial lung injury was suspected and corticosteroid therapy was administered which resulted in rapid clinical and radiological improvement. This is one of the few reported cases of interstitial lung disease due to infliximab in the psoriasis population. The patient had no pre-existing lung pathology, while his previous exposure to methotrexate was minimal and was not temporally associated with the induction of interstitial lung disease. PMID:23969008

Kakavas, Sotiris; Balis, Evangelos; Lazarou, Vasiliki; Kouvela, Marousa; Tatsis, Georgios

2013-01-01

125

Surface-induced superparamagnetic relaxation in nanoscale ferrihydrite particles  

SciTech Connect

The effect of surface on superparamagnetic relaxation for nanoscale ferrihydrite particles ({ital d}{approximately}5 nm) has been investigated using M{umlt o}ssbauer spectroscopy. With increasing surface chemisorption of SiO{sub 4}{sup 4{minus}}, the superparamagnetic transition temperature ({ital T}{sub {ital B}}) falls from 100 to 40 K and the transition sharpens. This indicates that the SiO{sub 4}{sup 4{minus}} species eliminate the surface unpaired spins and create a nonmagnetic medium, thereby significantly reducing the magnetic coupling between the particles. For ferrihydrite particles impregnated on a silica support, the particle interaction becomes negligible and the superparamagnetic transition occurs at a still lower temperature of {approximately}12 K; the spectra exhibit characteristic size-dependent features. {copyright} {ital 1996 The American Physical Society.}

Zhao, J.; Huggins, F.E.; Feng, Z.; Huffman, G.P. [The Consortium for Fossil Fuel Liquefaction Science, 341 Bowman Hall, University of Kentucky, Lexington, Kentucky 40506 (United States)] [The Consortium for Fossil Fuel Liquefaction Science, 341 Bowman Hall, University of Kentucky, Lexington, Kentucky 40506 (United States)

1996-08-01

126

Aging induced changes on NEXAFS fingerprints in individual combustion particles  

NASA Astrophysics Data System (ADS)

Soot particles can significantly influence the Earth's climate by absorbing and scattering solar radiation as well as by acting as cloud condensation nuclei. However, despite their environmental (as well as economic and political) importance, the way these properties are affected by atmospheric processing of the combustion exhaust gases is still a subject of discussion. In this work, individual soot particles emitted from two different vehicles, a EURO 2 transporter, a EURO 3 passenger car, and a wood stove were investigated on a single-particle basis. The emitted exhaust, including the particulate and the gas phase, was processed in a smog chamber with artificial solar radiation. Single particle specimens of both unprocessed and aged soot were characterized using near edge X-ray absorption fine structure spectroscopy (NEXAFS) and scanning electron microscopy. Comparison of NEXAFS spectra from the unprocessed particles and those resulting from exhaust photooxidation in the chamber revealed changes in the carbon functional group content. For the wood stove emissions, these changes were minor, related to the relatively mild oxidation conditions. For the EURO 2 transporter emissions, the most apparent change was that of carboxylic carbon from oxidized organic compounds condensing on the primary soot particles. For the EURO 3 car emissions oxidation of primary soot particles upon photochemical aging has likely contributed as well. Overall, the changes in the NEXAFS fingerprints were in qualitative agreement with data from an aerosol mass spectrometer. Furthermore, by taking full advantage of our in situ microreactor concept, we show that the soot particles from all three combustion sources changed their ability to take up water under humid conditions upon photochemical aging of the exhaust. Due to the selectivity and sensitivity of the NEXAFS technique for the water mass, also small amounts of water taken up into the internal voids of agglomerated particles could be detected. Because such small amounts of water uptake do not lead to measurable changes in particle diameter, it may remain beyond the limits of volume growth measurements, especially for larger agglomerated particles.

Zelenay, V.; Mooser, R.; Tritscher, T.; K?epelová, A.; Heringa, M. F.; Chirico, R.; Prévôt, A. S. H.; Weingartner, E.; Baltensperger, U.; Dommen, J.; Watts, B.; Raabe, J.; Huthwelker, T.; Ammann, M.

2011-11-01

127

Tungsten Particle-Induced Nicking of Supercoiled Plasmid DNA  

Microsoft Academic Search

Small particles of metallic tungsten, known also as tungsten microprojectiles, are routinely used for biotechnological purposes. In such applications, tungsten was observed to affect the integrity of plasmid DNA. Here we present evidence that interaction between tungsten particles and intact circular plasmids pU19, pUC119, and ColE1 may result in generation of a limited number of single-strand DNA breaks. As a

Barbara Mazu?; Cezary Krysiak; Jerzy Buchowicz

2000-01-01

128

Interleukin-35 induces regulatory B cells that suppress autoimmune disease.  

PubMed

Interleukin-10 (IL-10)-producing regulatory B (Breg) cells suppress autoimmune disease, and increased numbers of Breg cells prevent host defense to infection and promote tumor growth and metastasis by converting resting CD4(+) T cells to regulatory T (Treg) cells. The mechanisms mediating the induction and development of Breg cells remain unclear. Here we show that IL-35 induces Breg cells and promotes their conversion to a Breg subset that produces IL-35 as well as IL-10. Treatment of mice with IL-35 conferred protection from experimental autoimmune uveitis (EAU), and mice lacking IL-35 (p35 knockout (KO) mice) or defective in IL-35 signaling (IL-12R?2 KO mice) produced less Breg cells endogenously or after treatment with IL-35 and developed severe uveitis. Adoptive transfer of Breg cells induced by recombinant IL-35 suppressed EAU when transferred to mice with established disease, inhibiting pathogenic T helper type 17 (TH17) and TH1 cells while promoting Treg cell expansion. In B cells, IL-35 activates STAT1 and STAT3 through the IL-35 receptor comprising the IL-12R?2 and IL-27R? subunits. As IL-35 also induced the conversion of human B cells into Breg cells, these findings suggest that IL-35 may be used to induce autologous Breg and IL-35(+) Breg cells and treat autoimmune and inflammatory disease. PMID:24743305

Wang, Ren-Xi; Yu, Cheng-Rong; Dambuza, Ivy M; Mahdi, Rashid M; Dolinska, Monika B; Sergeev, Yuri V; Wingfield, Paul T; Kim, Sung-Hye; Egwuagu, Charles E

2014-06-01

129

Particle-Induced X-Ray Emission Analysis of Atmospheric Aerosols  

Microsoft Academic Search

We are developing a research program in ion-beam analysis (IBA) of atmospheric aerosols at the Union College Ion-Beam Analysis Laboratory to study the transport, transformation, and effects of airborne pollution in Upstate New York. The simultaneous applications of the IBA techniques of particle-induced X-ray emission (PIXE), Rutherford back-scattering spectrometry (RBS), particle-induced gamma-ray emission (PIGE), and proton elastic scattering analysis (PESA)

Colin Gleason; Charles Harrington; Katie Schuff; Maria Battaglia; Robert Moore; Colin Turley; Michael Vineyard; Scott Labrake

2010-01-01

130

Bystander effect induced by counted high-LET particles in confluent human fibroblasts: a mechanistic study  

Microsoft Academic Search

The possible mechanism of a radiation- induced bystander response was investigated by using a high-LET heavy particle microbeam, which allows se- lected cells to be individually hit with precise numbered particles. Even when only a single cell within the confluent culture was hit by one particle of 40Ar (1260 keV\\/m) or 20Ne (380 keV\\/ m), a 1.4-fold increase of micronuclei

CHUNLIN SHAO; YOSHIYA FURUSAWA; YASUHIKO KOBAYASHI; TOMOO FUNAYAMA; SEIICHI WADA

2003-01-01

131

Particle-induced damage and subsequent healing of materials: Erosion, corrosion and self-healing coatings  

Microsoft Academic Search

This review summarizes research on particle-induced damage and the subsequent repair of metallic materials. Metallic materials are damaged by solid particle impact via two damage processes: repeated plastic deformation and cutting. At a certain low-impact velocity, the particle does not skid, resulting in only plastic deformation with no damage by cutting. The critical impact velocity has been theoretically derived. Self-healing

Akihiro Yabuki

2011-01-01

132

Continuous-flow particle and cell separations in a serpentine microchannel via curvature-induced dielectrophoresis  

Microsoft Academic Search

Particle and cell separations are critical to chemical and biomedical analyses. This study demonstrates a continuous-flow\\u000a electrokinetic separation of particles and cells in a serpentine microchannel through curvature-induced dielectrophoresis.\\u000a The separation arises from the particle size-dependent cross-stream dielectrophoretic deflection that is generated by the\\u000a inherent electric field gradients within channel turns. Through the use of a sheath flow to focus

Junjie Zhu; Robert Cameron Canter; Gyunay Keten; Pallavi Vedantam; Tzuen-Rong J. Tzeng; Xiangchun Xuan

133

Two-dimensional soot-particle sizing by time-resolved laser-induced incandescence  

NASA Astrophysics Data System (ADS)

The evaluation of the temporal decay of the laser-induced incandescence (LII) signal from soot particles is introduced as a technique to obtain two-dimensional distributions of particle sizes and is applied to a laminar diffusion flame. This novel approach to soot sizing exhibits several theoretical and technical advantages compared with the established combination of elastic scattering and LII, especially as it yields absolute sizes of primary particles without requiring calibration.

Will, Stefan; Schraml, Stephan; Leipertz, Alfred

1995-11-01

134

Detection of charged particles emitted by electrolytically induced cold nuclear fusion  

Microsoft Academic Search

An attempt was made to obtain evidence for electrolytically induced cold nuclear fusion by detecting charged particles associated with the nuclear reaction. Charged particles were detected by a conventional silicon surface barrier detector attached close to the thin foil cathode which formed the bottom of an electrolysis cell. The efficiency and signal-to-noise ratio of this system are higher than those

Ryoichi Taniguchi; Takao Yamamoto; Setsuko Irie

1989-01-01

135

Hybrid lattice particle modeling of wave propagation induced fracture of solids  

Microsoft Academic Search

This paper presents a discrete dynamic fracture model, hybrid lattice particle modeling (HLPM), and its applications in the wave propagation induced fracture problems of solids. The HLPM is established based on a combination of the first author’s prior particle modeling (PM) technique with the conventional lattice modeling (LM) theory. The HLPM has the robustness of simulating the dynamic fragmentation of

G. Wang; A. Al-Ostaz; A. H.-D. Cheng; P. R. Mantena

2009-01-01

136

Electric field-induced motion of solid particles in two-dimensional fluids  

Microsoft Academic Search

Electric field induced motion of spherical and cylindrical glass particles were studied in a smectic A liquid crystal octyl cyanobiphenyl (8CB) medium. The particles were dispersed in the smectic A medium, sandwiched between to glass plates with conductive inner surfaces. Under DC fields the smectic layers become parallel to the glass substrates. Such configuration corresponds to a two dimensional isotropic

Antal Jackli; Guangxun Liao; Jack R. Kelly

2004-01-01

137

The Role of TLR and Chemokine in Wear Particle-Induced Aseptic Loosening  

PubMed Central

Wear particle-induced periprosthetic osteolysis remains the principal cause of aseptic loosening of orthopaedic implants. Monocytes/macrophages phagocytose wear particles and release cytokines that induce inflammatory response. This response promotes osteoclast differentiation and osteolysis. The precise mechanisms by which wear particles are recognized and induce the accumulation of inflammatory cells in the periprosthetic tissue have not been fully elucidated. Recent studies have shown that toll-like receptors (TLRs) contribute to the cellular interaction with wear particles. Wear particles are recognized by monocytes/macrophages through TLRs coupled with the adaptor protein MyD88. After the initial interaction, wear particles induce both local and systemic migration of monocytes/macrophages to the periprosthetic region. The cellular migration is mediated through chemokines including interleukin-8, macrophage chemotactic protein-1, and macrophage inhibitory protein-1 in the periprosthetic tissues. Interfering with chemokine-receptor axis can inhibit cellular migration and inflammatory response. This paper highlights recent advances in TLR, and chemokine participated in the pathogenesis of aseptic loosening. A comprehensive understanding of the recognition and migration mechanism is critical to the development of measures that prevent wear particle-induced aseptic loosening of orthopaedic implants.

Gu, Qiaoli; Shi, Qin; Yang, Huilin

2012-01-01

138

Walking-induced particle resuspension in indoor environments  

NASA Astrophysics Data System (ADS)

Resuspension of particles indoors increases the risk of consequent exposure through inhalation and non-dietary ingestion. Studies have been conducted to characterize indoor particle resuspension but results do not always agree, and there are still many open questions in this field. This paper reviews the recent research of indoor resuspension and summarizes findings to answer six critical questions: 1) How does the resuspension sources compared to other indoor sources; 2) How is resuspension determined and how does the resuspension measure change as a function of particle size; 3) What are the primary resuspension mechanisms; 4) What are the factors affecting resuspension; 5) What are the knowledge gaps and future research directions in this area; and 6) How can what we know about resuspension guide better exposure mitigation strategies? From synthesized results, we conclude that resuspension is an important source for indoor particulate matter, compared with other indoor sources. Among all existing quantification terms of resuspension, resuspension fraction has the least variation in its estimates by explicitly defining surface loading and walking frequency, and thus is recommended to be adopted in future research over other terms. Resuspension increases with particle size in the range of 0.7-10 ?m, although differences exist in resuspension estimates by orders of magnitude. The primary mechanism of particle resuspension involves rolling detachment, and the adhesive forces can be greatly reduced by microscopic surface roughness. Particle resuspension is by nature complicated, affected by various factors and their interactions. There are still many open questions to be answered to achieve an understanding of resuspension fundamentals. Given the complex and multidisciplinary nature of resuspension, understanding indoor particle resuspension behavior requires cross-disciplinary participation from experts in aerosol science, textile science, surface chemistry, electrostatics, and fluid mechanics.

Qian, Jing; Peccia, Jordan; Ferro, Andrea R.

2014-06-01

139

FACTORS THAT INFLUENCE THE RELATIVE POTENCY OF DIESEL EXHAUST PARTICLES AS ADJUVANTS IN ALLERGIC AIRWAY DISEASE  

EPA Science Inventory

Description: Studies have shown that diesel exhaust particles (DEP) worsen respiratory diseases including allergic asthma. The adjuvant effects of DEP in the airways have been widely reported; however, the precise determinants and mechanisms of these effects are ill-defined. S...

140

Testosterone induced priapism in two adolescents with sickle cell disease.  

PubMed

Priapism is common in pubertal males with sickle cell disease, but the association between low-dose exogenous testosterone administration and priapism in such patients has not been well documented. Two adolescents with homozygous sickle cell disease (SCD) and delayed maturation with behavioral problems developed priapism about one week after receiving an intramuscular injection of testosterone enanthate. Neither had a previous history of priapism. We conclude that testosterone should not be administered to male patients with SCD because of the risk of inducing priapism and possible impotence. PMID:8521195

Slayton, W; Kedar, A; Schatz, D

1995-01-01

141

DRIFT-INDUCED PERPENDICULAR TRANSPORT OF SOLAR ENERGETIC PARTICLES  

SciTech Connect

Drifts are known to play a role in galactic cosmic ray transport within the heliosphere and are a standard component of cosmic ray propagation models. However, the current paradigm of solar energetic particle (SEP) propagation holds the effects of drifts to be negligible, and they are not accounted for in most current SEP modeling efforts. We present full-orbit test particle simulations of SEP propagation in a Parker spiral interplanetary magnetic field (IMF), which demonstrate that high-energy particle drifts cause significant asymmetric propagation perpendicular to the IMF. Thus in many cases the assumption of field-aligned propagation of SEPs may not be valid. We show that SEP drifts have dependencies on energy, heliographic latitude, and charge-to-mass ratio that are capable of transporting energetic particles perpendicular to the field over significant distances within interplanetary space, e.g., protons of initial energy 100 MeV propagate distances across the field on the order of 1 AU, over timescales typical of a gradual SEP event. Our results demonstrate the need for current models of SEP events to include the effects of particle drift. We show that the drift is considerably stronger for heavy ion SEPs due to their larger mass-to-charge ratio. This paradigm shift has important consequences for the modeling of SEP events and is crucial to the understanding and interpretation of in situ observations.

Marsh, M. S.; Dalla, S.; Kelly, J.; Laitinen, T., E-mail: mike.s.marsh@gmail.com [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom)

2013-09-01

142

ZETA Potential Induced Particle Generation in SC2 Cleaning  

NASA Astrophysics Data System (ADS)

After etch and photo resist (PR) strip, particle and byproduct removal treatment is inevitable. SC1/SC2 cleaning process is one of the useful wet cleaning processes to remove them. In most cases, the equipment is batch type (25 or 50 wafers dip into bath) in which particles lifted from edge or backside of wafer move into chip easily by the stream of chemical. Especially in the process of film like Si3N4 with high dielectric constant, the particle issue is more serious. Following SC1 cleaning (main chemical is NH4OH), SC2 cleaning (main chemical is HCl) causes particles to be attached to wafer. The lifted particles in SC1 cleaning are attached to wafer strongly by ZETA potential, which is enhanced when the PH of chemical is lower than 4 (PH of SC2 chemical is about 1.3). SC2 cleaning after SC1 cleaning is not desirable process sequence. But, SC2 chemical is useful for removing metal contamination generated in etch equipment during the etch process. Skipping SC2 cleaning is desirable in the process which metal contamination has no impact on. But, if you want to use SC2 cleaning or other acid chemical (PH below 4) for a guarantee of quality of device, it should be processed before SC1 cleaning.

Mun, Seong Yeol; Yoon, Ki Chae; An, Byeong Woo

2002-12-01

143

Losartan Inhibits Nuclear Factor-?B Activation Induced by Small, Dense LDL Cholesterol Particles in Human Umbilical Vein Endothelial Cells?  

PubMed Central

Objective We aimed to investigate how losartan exerts protective effects on human umbilical vein endothelial cell injury induced by small, dense, LDL (sLDL) cholesterol particles. Methods sLDL cholesterol was isolated by a 2-steps method and the nuclear translocation and activation of nuclear factor-?B (NF-?B) in endothelial cells was observed by confocal microscopy and electrophoretic mobility shift assays. Results Losartan greatly inhibited the nuclear translocation of NF-?B induced by sLDL cholesterol in a dose-dependent manner. Conclusions sLDL cholesterol may be involved in endothelial dysfunction possibly through NF-?B activation; losartan protects against sLDL cholesterol-inducing endothelial cell injury by inhibiting NF-?B activation, suggesting that losartan may play a role in the prevention and treatment of cardiovascular disease.

Guo, Gonghui; Cheng, Xiaojing; Fu, Rong

2013-01-01

144

Hypericin suppresses osteoclast formation and wear particle-induced osteolysis via modulating ERK signalling pathway.  

PubMed

Osteoclast-induced bone resorption and wear-particle-induced osteolysis leads to prosthetic loosening, one of the most common causes of joint implant failure, resulting in revision surgery. Thus, inhibition of osteoclastic bone resorption, which further prevents wear particle-induced osteolysis, is a potential treatment strategy for prosthetic loosening. Here, we examined the therapeutic effect of hypericin (HP), which was photosensitive, on osteoclastogenesis and wear particle-induced osteolysis in the absence of visible light. HP inhibited RANKL-induced osteoclast differentiation in bone marrow macrophages (BMMs) and RAW264.7 cell line without any evidence of cytotoxicity. The bone-resorbing activity of mature osteoclasts was significantly inhibited by HP. As HP has been previously reported to inhibit signalling pathway such as ERK and NF-?B in other cells, which is also important in osteoclast differentiation. We thus examined the molecular mechanism and showed that HP significantly inhibited the ERK/mitogen-activated protein kinase (MAPK) signalling pathway without affecting nuclear factor kappaB (NF-?B), c-Jun N-terminal kinase (JNK) and p38 signalling in RANKL-stimulated BMMs. Further in vivo studies revealed HP attenuated osteoclast formation and subsequently prevented wear particle-induced bone erosion. Taken together, the results suggest that HP inhibits RANKL-mediated osteoclastogenesis via affecting ERK signalling in vitro and suppresses wear particle-induced osteolysis in vivo. We therefore conclude that HP may be an innovative and safe alternative treatment for osteoclast-related prosthetic loosening. PMID:24950468

Ouyang, Zhengxiao; Zhai, Zanjing; Li, Haowei; Liu, Xuqiang; Qu, Xinhua; Li, Xianan; Fan, Qiming; Tang, Tingting; Qin, An; Dai, Kerong

2014-08-01

145

Toxin-Induced and Genetic Animal Models of Parkinson's Disease  

PubMed Central

Parkinson's disease (PD) is a common progressive neurodegenerative disorder. The major pathological hallmarks of PD are the selective loss of nigrostriatal dopaminergic neurons and the presence of intraneuronal aggregates termed Lewy bodies (LBs), but the pathophysiological mechanisms are not fully understood. Epidemiologically, environmental neurotoxins such as pesticides are promising candidates for causative factors of PD. Oxidative stress and mitochondrial dysfunction induced by these toxins could contribute to the progression of PD. While most cases of PD are sporadic, specific mutations in genes that cause familial forms of PD have led to provide new insights into its pathogenesis. This paper focuses on animal models of both toxin-induced and genetically determined PD that have provided significant insight for understanding this disease. We also discuss the validity, benefits, and limitations of representative models.

Hisahara, Shin; Shimohama, Shun

2011-01-01

146

Simvastatin pretreatment prevents ambient particle-induced lung injury in mice.  

PubMed

Air particulate pollution negatively affects the health of the population exposed, being the lung the main target organ. Simvastatin (SV) is widely used for the prevention and risk reduction of coronary disease. Its pleiotropic effects may provide benefit for lung diseases. Here, we investigated the preventive effect of simvastatin pretreatment on acute intranasal exposure to ROFA (Residual Oil Fly Ash), and UAP (Urban Air Particle from Buenos Aires). Male BALB/c mice were randomized in two groups to receive either saline (control, C) solution or SV (1?mg/kg bw /day; ip) for 14 days. After SV treatment, ROFA or UAP (1?mg/kg bw) or saline were intranasally delivered for 24 hours generating 4 subgroups for the ROFA experiment (C, SV, ROFA and SV+ROFA) and 3 subgroups for the UAP experiment (C, SV, UAP and SV+UAP). Biomarkers of lung injury were examined in BAL cells evaluating total cell number (TCN), cell differential (CD) and superoxide anion generation (O2-), in lung homogenates assessing superoxide dismutase activity (SOD) and tumor necrosis factor ? (TNF?); and in blood samples determining interleukin 6 (IL-6) production. ROFA and UAP produced an acute pulmonary injury, characterized by an increase in BAL, TCN and neutrophilic inflammatory influx, a rise in O2- generation, and production of the proinflammatory TNF? cytokine. SV pretreatment had no significant effect per se on any of these biomarkers but prevented the pulmonary cytotoxicity and inflammation induced by ROFA and UAP. Our results encourage further studies to determine the preventive effects on lung injury induced by air pollutants. PMID:22122302

Ferraro, Sebastian A; Yakisich, Juan S; Gallo, Francisco T; Tasat, Deborah R

2011-12-01

147

Small glass particle cloud generation induced by laser ablation  

Microsoft Academic Search

Burst of small fragments of glass has been evidenced in the present study, when ground glass surface is laser ablated. Production of macro particles by laser ablation is an inherent characteristic of ground glass, and no similar phenomena have been observed in case of metal or polymer ablation. In this case, no additional metal coating has been made to further

Kunihito Nagayama; Yuriko Kotsuka; Motonao Nakahara; Shiro Kubota

2005-01-01

148

Ionizing Radiation Induced Catalysis on Metal Oxide Particles  

Microsoft Academic Search

This project was conducted to determine if ionizing radiation could be used to catalytically destroy organics over semiconducting metal oxide particles. We focused primarily on the destruction of organic chelating agents, such as EDTA, which are known to hamper the separation of radionucleii (such as Sr or Am) from tank waste using current ion exchange methods. Our objective was to

Michael A

1999-01-01

149

Exciton Sounding of ?-Particle Induced Radiation Defects in Anthracene  

Microsoft Academic Search

Anthracene crystals have been irradiated ? to ? by ?-particles at 28.3, 30.00 and 32.26 MeV. A laser beam focused to a line ? to the ? direction is used to generate triplet excitons at 50 micron intervals in this direction. The spatial distribution of residual damage is determined from the variations in the delayed fluorescence and triplet exciton lifetime.

S. Arnold; H. T. Hu; M. Pope

1976-01-01

150

Effects of concentrated ambient particles and diesel engine exhaust on allergic airway disease in Brown Norway rats.  

PubMed

Increased concentrations of airborne fine particulate matter (PM2.5; particulate matter with an aerodynamic diameter < or = 2.5 microm) are associated with increases in emergency room visits and hospitalizations of asthmatic patients. Emissions from local stationary combustion sources (e.g., coal-burning power plants) or mobile motor vehicles (e.g., diesel-powered trucks) have been identified as potential contributors to the development or exacerbation of allergic airway disease. In the present study, a rodent model of allergic airway disease was used to study the effects of concentrated ambient particles (CAPs) or diesel engine exhaust (DEE) on the development of allergic airway disease in rats sensitized to the allergen ovalbumin (OVA). The overall objective of our project was to understand the effects of PM2.5 on the development of OVA-induced allergic airway disease. Our specific aims were to test the following hypotheses: (1) exposure to CAPs during OVA challenge enhances epithelial remodeling of the airway and inflammation in rats previously sensitized to the allergen; and (2) exposure to DEE during OVA sensitization, or during OVA challenge, exacerbates epithelial remodeling of the airway and inflammation in rats. In the DEE studies, Brown Norway (BN) rats were sensitized with three daily intranasal (IN) instillations of 0.5% OVA, and then two weeks later were challenged with IN OVA or saline for 3 consecutive days. Rats were exposed to DEE diluted to mass concentrations of 30 or 300 microg/m3 diesel exhaust particles (DEPs) or to filtered air during either the sensitization or challenge periods. For the CAPs studies, the same OVA sensitization and challenge rat model was used but exposures to Detroit, Michigan, CAPs were limited to the OVA challenge period. Two separate 3-day CAPs exposures were conducted (week 1, high mean mass concentration = 595 microg/m3; week 2, low mean mass concentration = 356 microg/m3) during OVA challenge. In both the DEE and CAPs studies, rats were killed 24 hours after the last OVA challenge, bronchoalveolar lavage fluid (BALF) was collected and analyzed for cellularity and secreted mediators, and lungs and nose were processed for histopathologic examination and morphometric analysis of intraepithelial mucosubstances (IM). The results of our animal inhalation studies in the southwest (SW) Detroit community, an area with elevated ambient PM2.5 concentrations, suggested that, during allergen challenge, exposure to CAPs that were predominantly associated with emissions from combustion sources markedly enhanced the OVA-induced allergic airway disease, which was characterized by an increased infiltration in the lungs of eosinophilic and lymphocytic inflammation, increased IM in conducting airways, and increased concentrations in BALF of mucin-specific proteins and inflammatory cytokines. These findings suggest that urban airborne PM2.5 derived from stationary combustion sources (e.g., refineries, coal-burning power plants, waste-treatment plants) may enhance the development of human allergic airway diseases like childhood asthma. Previous animal inhalation studies in this community have also suggested that these fine, ambient combustion-derived particles may also exacerbate preexisting allergic airway disease. In contrast to our CAPs studies in Detroit, the controlled DEE exposures of allergen-sensitized BN rats, during either allergen sensitization or challenge periods, caused only a few mild modifications in the character of the allergen-induced disease. This finding contrasts with other reported studies that indicate that DEPs at relatively higher exposure doses do enhance allergic airway disease in some rodent models. The reasons for these disparities between studies likely reflect differences in exposure dose, animal models, the timing of exposures to the allergens and DEP exposures, the methods of allergen sensitization and challenge, or physicochemical differences among DEEs. PMID:20198910

Harkema, Jack R; Wagner, James G; Kaminski, Norbert E; Morishita, Masako; Keeler, Gerald J; McDonald, Jacob D; Barrett, Edward G

2009-11-01

151

Particle induced x-ray emission (PIXE) measurement of the Cd content in animal tissues.  

National Technical Information Service (NTIS)

Particle induced x-ray emission (PIXE) measurements were performed on thin samples prepared from different rabbit tissues, using 3 MeV proton beam for inducing x-rays from the animal tissues. This method is very sensitive and very small amounts of trace e...

Le Huong Quynh I. Demeter K. Hollos-Nagy Z. Szoekefalvi-Nagy

1989-01-01

152

Charged Particle-Induced Secondary and Backscattered Electron Emissions From Insulator Materials  

Microsoft Academic Search

In previous studies of insulators, serious discrepancies have been reported for the electron and ion-induced electron emission properties. Making such measurements is difficult since insulators can charge under particle beam bombardment. We present work undertaken by our group to make consistent and accurate measurements of the electron and ion-induced yields for numerous insulators using innovative instrumentation involving a multiple sample

Clint Thomson; Albert Chang; John Dennison; Neal Nickles

2002-01-01

153

Role of direct estrogen receptor signaling in wear particle-induced osteolysis  

PubMed Central

Estrogen withdrawal following surgical ovariectomy was recently shown to mitigate particle-induced osteolysis in the murine calvarial model. Currently, we hypothesize that estrogen receptors (ERs) were involved in this paradoxical phenomenon. To test this hypothesis, we first evaluated polyethylene (PE) particle-induced osteolysis in the murine calvarial model, using wild type (WT) C57BL6J female mice, ER? deficient (ER?KO) mice, and WT mice either treated with 17?-estradiol (E2) or with the ER pan-antagonist ICI 182,780. According to micro-CT and histomorphometry, we showed that bone resorption was consistently altered in both ER?KO and ICI 182,780 treated mice as compared to WT and E2 groups. Then, we demonstrated that ER disruption consistently decreased both PE and polymethylmethacrylate (PMMA) particle-induced production of TNF-? by murine macrophages in vitro. Similar results were obtained following ER blockade using ICI 182,780 in RAW 264.7 and WT macrophages. ER disruption and pre treatment with ICI 182,780 resulted in a consistent down-regulation of particle-induced TNF-? mRNA expression relative to WT macrophages or untreated RAW cells. These results indicate that the response to wear particles involves estrogen receptors in female mice, as part of macrophage activation. Estrogen receptors may be considered as a future therapeutic target for particle-induced osteolysis.

Nich, Christophe; Rao, Allison J.; Valladares, Roberto D.; Li, Chenguang; Christman, Jane E.; Antonios, Joseph K.; Yao, Zhenyu; Zwingenberger, Stefan; Petite, Herve; Hamadouche, Moussa; Goodman, Stuart B.

2014-01-01

154

Curcumin reduces ?-synuclein induced cytotoxicity in Parkinson's disease cell model  

PubMed Central

Background Overexpression and abnormal accumulation of aggregated ?-synuclein (?S) have been linked to Parkinson's disease (PD) and other synucleinopathies. ?S can misfold and adopt a variety of morphologies but recent studies implicate oligomeric forms as the most cytotoxic species. Both genetic mutations and chronic exposure to neurotoxins increase ?S aggregation and intracellular reactive oxygen species (ROS), leading to mitochondrial dysfunction and oxidative damage in PD cell models. Results Here we show that curcumin can alleviate ?S-induced toxicity, reduce ROS levels and protect cells against apoptosis. We also show that both intracellular overexpression of ?S and extracellular addition of oligomeric ?S increase ROS which induces apoptosis, suggesting that aggregated ?S may induce similar toxic effects whether it is generated intra- or extracellulary. Conclusions Since curcumin is a natural food pigment that can cross the blood brain barrier and has widespread medicinal uses, it has potential therapeutic value for treating PD and other neurodegenerative disorders.

2010-01-01

155

New molecular insights into inflammatory bowel disease-induced diarrhea  

PubMed Central

Diarrhea is one of the common symptoms that significantly affects quality of life in patients with inflammatory bowel disease (IBD). The clinical manifestation of diarrhea is mainly dependant on the type of IBD and the location, extent and severity of intestinal inflammation. Understanding the pathophysiologic mechanisms of diarrhea in patients with IBD will be beneficial to developing effective treatments for IBD-associated diarrhea. In recent years, modern molecular techniques have been used intensively to dissect the role of the intestinal microbiota, epithelial barrier and the host immune system in the mechanisms of IBD-induced diarrhea. These studies have significantly advanced our knowledge of the mechanisms of IBD-induced diarrhea. In this article, we focus on the new and critical molecular insights into the contributions of the intestinal microbiota, epithelial tight junctions, proinflammatory cytokines and microRNA as potential mechanisms underlying to IBD-induced diarrhea.

Tang, Yueming; Forsyth, Christopher B; Keshavarzian, Ali

2011-01-01

156

Monitoring process induced attrition of drug substance particles within formulated blends.  

PubMed

The aim of the study was to investigate the impact of unit processing steps such as blending, cone milling and powder feeding systems on the particle size of a formulated API. The particle properties of a single component (API) within formulated samples were tracked using an image based particle characterisation system with an integrated Raman probe. In addition to the primary aim, the impact of excipient selection was also assessed. The study demonstrated the ability to track the size and shape of particles of a single component within a blended system. Process induced attrition can affect significant changes in the size and shape characteristics of the API particles. Whilst blending and cone milling were found to have minimal impact on the API properties, significant particle attrition was induced through transmission of the formulations through a powder feeding system. The impact of excipients within the formulated blends on API attrition propensity was observed to be low. The findings suggest that the propensity for particles to undergo process induced attrition should be taken into consideration when designing a manufacturing process and/or relating initial particle properties to the performance of intermediate or final dosage forms. PMID:24793838

Gamble, John F; Hoffmann, Magnus; Hughes, Helen; Hutchins, Paul; Tobyn, Mike

2014-08-15

157

On the effect of induced electro-osmosis on a cylindrical particle next to a surface.  

PubMed

The effect of induced electro-osmosis on a cylindrical particle positioned next to a planar surface (wall) is studied theoretically both under the thin double layer approximation utilizing the Smoluchowski slip velocity approximation and under thick electric double layer conditions by solving the Poisson-Nernst-Planck (PNP) equations. The imposed, undisturbed electric field is parallel to the planar surface. The induced hydrodynamic and electrostatic forces are calculated as functions of the particle's and the medium's dielectric constants and the distance between the particle and the surface. The resultant force acting on the particle is directed normal to and away from the wall. The presence of such a repulsive force may adversely affect the interactions between macromolecules suspended in solution and wall-immobilized molecules and may be significant to near-wall particle imaging velocimetry (PIV) in electrokinetic flows. PMID:17311434

Zhao, Hui; Bau, Haim H

2007-03-27

158

Luminescence induced by high-velocity impacts of metallic particles on metal surfaces  

SciTech Connect

On impact of metallic particles on a metal surface light can be emitted from the region of impact. This phenomenon is studied experimentally for impact conditions that are typical of the cold spray deposition process, i.e., particle diameters and velocities are of the order of 10{sup -5} m and 500 m/s, respectively. The characteristics of impact-induced luminescence are analyzed. It is found that the intensity of luminescence depends not only on the energy of the impinging particles and on the stresses produced on impact but also on the particular combination of materials of the particles and the plate. Possible sources of luminescence are discussed.

Klinkov, Konstantin V.; Rein, Martin [Institute of Aerodynamics and Flow Technology, DLR, Bunsenstrasse 10, 37073 Goettingen (Germany)

2006-07-01

159

Fluctuation induced equality of multi-particle eccentricities for four or more particles  

NASA Astrophysics Data System (ADS)

We discuss eccentricities (ellipticity and triangularity) generated in nucleus-nucleus and proton-nucleus collisions. We define multi-particle eccentricities ?n{m} which are associated with the n'th angular multipole moment for m particles. We show that in the limit of fluctuation dominance all of the ?n{m}'s are approximately equal for m?4. For dynamics linearly responding to these eccentricities such as hydrodynamics, these relations among eccentricities are translated into relations among flow moments vn{m}. We explicitly demonstrate it with hydrodynamic calculations.

Bzdak, Adam; Bozek, Piotr; McLerran, Larry

2014-07-01

160

Apoptotic and inflammatory effects induced by different particles in human alveolar macrophages.  

PubMed

Pollutant particles induce apoptosis and inflammation, but the relationship between these two biological processes is not entirely clear. In this study, we compared the proapoptotic and proinflammatory effects of four particles: residual oil fly ash (ROFA), St. Louis particles SRM 1648 (SL), Chapel Hill PM10 (CHP), and Mount St. Helens dust (MSH). Human alveolar macrophages (AM) were incubated with these particles at 100 microg/ml. Cell death was assessed by annexin V (AV) expression, histone release, nuclear morphology, caspase 3-like activity and release of caspase 1 for apoptosis, and propidium iodide (PI) for necrosis, and inflammation was measured by interleukin (IL)-1beta and IL-6. We found that particle effects on these cell death measurements varied, and ROFA affected most (four out of five) endpoints, including nuclear morphological changes. CHP and SL also caused necrosis. For cytokine release, the potency was CHP > SL > ROFA > MSH. The proapoptotic and proinflammatory effects induced by the whole particles were unaltered after the particles were washed with water. The water-soluble fraction was relatively inactive, as were individual soluble metals (V, Ni, Fe). ROFA-induced nuclear fragmentation was associated with upregulation and mitochondrial release of apoptosis-inducing factor (AIF), a caspase-independent chromatin condensation factor, and upregulation of DNase II, a lysosomal acid endonuclease. These results indicate that the potential for particles to induce apoptosis does not correlate with their proinflammatory properties, although active components for both processes reside in the water-insoluble core. Both apoptosis and inflammatory endpoints should be included when the toxicity of different pollutant particles is assessed. PMID:15764474

Huang, Yuh-Chin T; Li, Zhuowei; Harder, Shirley D; Soukup, Joleen M

2004-12-15

161

Small glass particle cloud generation induced by laser ablation  

NASA Astrophysics Data System (ADS)

Burst of small fragments of glass has been evidenced in the present study, when ground glass surface is laser ablated. Production of macro particles by laser ablation is an inherent characteristic of ground glass, and no similar phenomena have been observed in case of metal or polymer ablation. In this case, no additional metal coating has been made to further enhance absorption of laser pulse. Pulse laser shadowgraph has been taken to study the details of the phenomena in air and in vacuum. At least in vacuum, particle burst is found almost normal to the surface. By using ns-duration Nd:YAG laser of 100 mJ/pulse, observed particle velocity ranges 0.5 km/s to 1.5 km/s in case of in air and the maximum velocity is extended up to 1.5-2 km/s in vacuum. SEM observation of the ground surface reveals that glass surface is covered with micro cracks with several microns deep, which might attribute to macro particle production. In this sense, not surface roughness but also surface structure will be important in the ablation phenomena of glass. It is plausible that absorption of laser beam at the glass surface causes spallation like phenomena as well as production of an amount of plasma, and the plasma production might be responsible for the acceleration of broken fragments of glass. We applied the phenomena to ignite PETN powder explosive, and succeeded in igniting PETN powder only by laser ablation of ground glass.

Nagayama, Kunihito; Kotsuka, Yuriko; Nakahara, Motonao; Kubota, Shiro

2005-03-01

162

Bootstrap current induced by fusion born alpha particles  

SciTech Connect

The bootstrap current produced by fusion born alpha particles is obtained, retaining effects of slowing down drag, pitch angle scattering, and arbitrary aspect ratio. The result is presented both as a summation of a rapidly converging series and a simple Pade approximation good for arbitrary aspect ratio. Quantitative results are derived using the International Thermonuclear Experimental Reactor (ITER) (Plasma Phys. Controlled Nucl. Fusion Res. (International Atomic Energy Agency, Vienna, 1989), Vol. 3, p. 214) parameters.

Hsu, C.T.; Shaing, K.C.; Gormley, R.P.; Sigmar, D.J. (Massachusetts Institute of Technology, Plasma Fusion Center, 167 Albany Street, NW16-260, Cambridge, Massachusetts 02139 (United States))

1992-12-01

163

Disease modeling and drug screening for neurological diseases using human induced pluripotent stem cells  

PubMed Central

With the general decline of pharmaceutical research productivity, there are concerns that many components of the drug discovery process need to be redesigned and optimized. For example, the human immortalized cell lines or animal primary cells commonly used in traditional drug screening may not faithfully recapitulate the pathological mechanisms of human diseases, leading to biases in assays, targets, or compounds that do not effectively address disease mechanisms. Recent advances in stem cell research, especially in the development of induced pluripotent stem cell (iPSC) technology, provide a new paradigm for drug screening by permitting the use of human cells with the same genetic makeup as the patients without the typical quantity constraints associated with patient primary cells. In this article, we will review the progress made to date on cellular disease models using human stem cells, with a focus on patient-specific iPSCs for neurological diseases. We will discuss the key challenges and the factors that associated with the success of using stem cell models for drug discovery through examples from monogenic diseases, diseases with various known genetic components, and complex diseases caused by a combination of genetic, environmental and other factors.

Xu, Xiao-hong; Zhong, Zhong

2013-01-01

164

Microembolic Renal Disease in Rats Induced with Sephadex  

PubMed Central

Sephadex particles (20-80 ? in size) were injected into the abdominal aorta of 134 male Sprague-Dawley rats near the renal arteries. In 31 rats, the right kidney was then removed. The Sephadex particles lodged in glomerular capillaries, afferent glomerular arterioles and interlobular arteries, creating renal infarcts, some of which were grossly visible. Shortly after injection, arterial blood pressure rose significantly in most animals. The hypertension in uninephrectomized rats was not demonstrably different from that in rats with two Kidneys. Severity and duration of hypertension (up to 8 months) were positively correlated with the number of Sephadex particles in renal vessels, and there was also a positive correlation between the degree of hypertension and serum urea nitrogen levels, and between degree of hypertension and degree of cardiac hypertrophy. The vascular permeability in acutely hypertensive rats was abnormal, as judged from penetration of iron-dextran into vessel walls. This experimental model resembles atheromatous microembolic renovascular disease, which may play a significant role in the pathogenesis of unexplained hypertension in patients with advanced aortic atherosclerosis. ImagesFig 12Fig 13Fig 5Fig 6Fig 7Fig 14Fig 8Fig 9Fig 1Fig 10Fig 11Fig 2Fig 3Fig 4

Solez, K.; Richter, G. W.

1972-01-01

165

Continuous manipulation and separation of particles using combined obstacle- and curvature-induced direct current dielectrophoresis.  

PubMed

This paper presents a novel dielectrophoresis-based microfluidic device incorporating round hurdles within an S-shaped microchannel for continuous manipulation and separation of microparticles. Local nonuniform electric fields are generated due to the combined effects of obstacle and curvature, which in turn induce negative dielectrophoresis forces exerting on the particle that transport throughout the microchannel electrokinetically. Experiments were conducted to demonstrate the controlled trajectories of fix-sized (i.e. 10 or 15 ?m) polystyrene particles, and size-dependent separation of 10 and 15 ?m particles by adjusting the applied voltages at the inlet and outlets. Numerical simulations were also performed to predict the particle trajectories, which showed reasonable agreement with experimentally observed results. Compared to other microchannel designs that make use of either obstacle or curvature individually for inhomogeneous electric fields, the developed microchannel offers advantages such as improved controllability of particle motion, lower requirement of applied voltage, reduced fouling, and particle adhesion, etc. PMID:23436345

Li, Ming; Li, Shunbo; Li, Weihua; Wen, Weijia; Alici, Gursel

2013-04-01

166

In vivo Expression of Inducible Nitric Oxide Synthase in Experimentally Induced Neurologic Diseases  

Microsoft Academic Search

The purpose of this study was to investigate the induction of inducible nitric oxide synthase (iNOS) mRNA in the brain tissue of rats and mice under the following experimental conditions: in rats infected with borna disease virus and rabies virus, in mice infected with herpes simplex virus, and in rats after the induction of experimental allergic encephalitis. The results showed

Hilary Koprowski; Yong Mu Zheng; Ellen Heber-Katz; Nigel Fraser; Lucy Rorke; Zhen Fang Fu; Cathleen Hanlon; Bernhard Dietzschold

1993-01-01

167

Induced phagocytic particle uptake into a giant unilamellar vesicle.  

PubMed

Phagocytosis, the uptake and ingestion of solid particles into living cells, is a central mechanism of our immune system. Due to the complexity of the uptake mechanism, the different forces involved in this process are only partly understood. Therefore the usage of a giant unilamellar vesicle (GUV) as the simplest biomimetic model for a cell allows one to investigate the influence of the lipid membrane on the energetics of the uptake process. Here, a photonic force microscope (PFM) is used to approach an optically trapped 1 ?m latex bead to an immobilized GUV to finally insert the particle into the GUV. By analysing the mean displacement and the position fluctuations of the trapped particle during the uptake process in 3D with nanometre precision, we are able to record force and energy profiles, as well as changes in the viscous drag and the stiffness. After observing a global followed by a local deformation of the GUV, we measured uptake energies of 2000 kT to 5500 kT and uptake forces of 4 pN to 16 pN for Egg-PC GUVs with sizes of 18-26 ?m and varying membrane tension. The measured energy profiles, which are compared to a Helfrich energy model for local and global deformation, show good coincidence with the theoretical results. Our proof-of-principle study opens the door to a large number of similar experiments with GUVs containing more biochemical components and complexity. This bottom-up strategy should allow for a better understanding of the physics of phagocytosis. PMID:24676395

Meinel, Andreas; Tränkle, Benjamin; Römer, Winfried; Rohrbach, Alexander

2014-05-28

168

Wave induced transport and mixing of buoyant particles  

NASA Astrophysics Data System (ADS)

The modeling of wave-current and wave-turbulence interactions have received much attention during recent years. Both the breaking of surface waves and the inclusion of the Stokes shear production have been shown to increase the upper ocean turbulence. Furthermore the Coriolis force acting on the Stokes drift redistributes the momentum in the upper ocean, leading to a deflection of the currents. An important application affected by these processes that still needs to be studied is the mixing and drift of particles. Using an ocean column model, modified to take surface wave effects into account, we investigate how the increased mixing by wave breaking and Stokes shear production as well as the stronger veering by the Coriolis-Stokes force effects the drift of suspended particles. Here the suspended particles are buoyant tracers that can represent oil droplets or plankton, for example fish eggs and larvae. The energy and momentum fluxes as well as the Stokes drift depend on the directional wave spectrum that can be obtained from a wave model or from observations. Comparing with classical Ekman theory some physical effects on the system are studied, and as a realistic test case we use the model to study the oil drift after an offshore oil spill that took place outside the western coast of Norway in 2007. During this accident the average net drift of oil was observed to be approximately 0.1% of the wind speed at an angle of about 90-120 degrees to the right, far slower and more deflected away from the wind direction than predicted by both numerical and empirical models. With wind and wave forcing from ECMWF reanalysis data, it is shown that the wave effects are important for the resultant drift in this case, and has the potential to improve drift forecasting.

Drivdal, Magnus; Broström, Göran; Christensen, Kai H.

2014-05-01

169

Coarsening of extracellularly biosynthesized cadmium crystal particles induced by thioacetamide in solution.  

PubMed

A novel coarsening route for extracellularly biosynthesized cadmium nanocrystals was investigated for the first time. In this process, the white rot fungus Coriolus versicolor was employed to take up cadmium ions and synthesize extracellular cadmium crystal particles. The coarsening of the particles was induced by thioacetamide under certain conditions. Scanning electron microscopy showed that the formed cadmium crystal particles were coarsened from about 100nm to 2-3?m. The corresponding energy-dispersive X-ray spectra confirmed the presence of proteins in the particles. The maximum removal efficiency of Cd(II) increased from 17% to 87%, and the corresponding sorption capacity of biomass increased from 4 to 24mgg(-1) with the completion of the coarsening process. The properties of the coarsened particles were also examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD analysis of fungal mycelial pellets embedded with the coarsened particles confirmed the formation of cubic crystalline cadmium sulfide particles. The TEM results suggest that the coarsened particles were composed of clusters of several smaller particles. The changes in the functional groups on the biomass surface were studied through Fourier transform infrared spectroscopy. Based on the results above, a possible mechanism for the formation and coarsening of cadmium crystal particle is also discussed. PMID:21489598

Chen, Gui-Qiu; Zou, Zheng-Jun; Zeng, Guang-Ming; Yan, Ming; Fan, Jia-Qi; Chen, An-Wei; Yang, Fan; Zhang, Wen-Juan; Wang, Liang

2011-05-01

170

Transition induced by fixed and freely convecting spherical particles in laminar boundary layers  

NASA Astrophysics Data System (ADS)

An experimental and analytical study of aspects of transition induced by disturbances from spherical particles in laminar boundary layers is discussed. The generation of turbulent wedges by fixed spherical particles in a laminar boundary layer on or near the surface of a flat plate is considered experimentally using flow visualization with fluorescent dye and laser Doppler velocimetry. Turbulent spots generated by freely convecting spherical particles that are released in the freestream to fall into a flat plate laminar boundary layer and impact the plate are also discussed. A combination of dye flow visualization and a video based particle tracking technique was used to study the convecting particle problem. Although the Reynolds number at the critical condition for turbulent wedge generation by fixed particles and turbulent spot generation by convecting particles are similar, transition in these two situations appears to be fundamentally different. The development of a turbulent wedge near the critical condition is a relatively gradual process. In contrast, turbulent spots form relatively quickly after the convecting particles enter the boundary layer and impact the plate. Turbulent wedge formation downstream of a fixed particle results from the destabilization of the near wall flow by the vortical structures shed into particle wake. This shedding process is dominated by periodically shed loop shaped hairpin vortices. Observation of subharmonic oscillations at 1/2 and 1/4 of this shedding frequency suggest that a chaotic route to turbulence by a series of period doubling bifurcations is possible.

Petrie, H. L.; Morris, P. J.; Bajwa, A. R.; Vincent, D. C.

1993-08-01

171

Measurement of Fluorescence Spectra from Ambient Aerosol Particles Using Laser-induced Fluorescence Technique  

NASA Astrophysics Data System (ADS)

To obtain the information of composition of organic aerosol particles in atmosphere, we developed an instrument using laser-induced fluorescence (LIF) technique. To measure the fluorescence from a particle, we employed two lasers. Scattering light signal derived from a single particle upon crossing the 635nm-CW laser triggers the 266nm-pulsed laser to excite the particle. Fluorescence from the particle in the wavelength range 300-600nm is spectrally dispersed by a grating spectrometer and then detected by a 32-Ch photo-multiplier tube(PMT). The aerosol stream is surrounded by a coaxial sheath air flow and delivered to the optical chamber at atmospheric pressure. Using PSL particles with known sizes, we made a calibration curve to estimate particle size from scattering light intensity. With the current setup of the instrument we are able to detect both scattering and fluorescence from particles whose diameters are larger than 0.5um. Our system was able to differentiate particles composed of mono-aromatic species (e.g. Tryptophan) from those of Riboflavin, by their different fluorescence wavelengths. Also, measurements of fluorescence spectra of ambient particles were demonstrated in our campus in Yokosuka city, facing Tokyo bay in Japan. We obtained several types of florescence spectra in the 8 hours. Classification of the measured fluorescence spectra will be discussed in the presentation.

Taketani, F.; Kanaya, Y.; Nakamura, T.; Moteki, N.; Takegawa, N.

2011-12-01

172

Ripple-induced energetic particle loss in tokamaks  

SciTech Connect

The threshold for stochastic transport of high energy trapped particles in a tokamak due to toroidal field ripple is calculated by explicit construction of primary resonances, and a numerical examination of the route to chaos. Critical field ripple amplitude is determined for loss. The expression is given in magnetic coordinates and makes no assumptions regarding shape or up-down symmetry. An algorithm is developed including the effects of prompt axisymmetic orbit loss, ripple trapping, convective banana flow, and stochastic ripple loss, which gives accurate ripple loss predictions for representative Tokamak Fusion Test Reactor [R. Hawryluk, Plasma Phys. Controlled Fusion {bold 33}, 1509 (1991)] and International Thermonuclear Experimental Reactor [K. Tomabechi, {ital Proceedings} {ital of} {ital the} 12{ital th} {ital International} {ital Conference} {ital on} {ital Plasma} {ital Physics} {ital and} {ital Controlled} {ital Nuclear} {ital Fusion} {ital Research} (International Atomic Energy Agency, Vienna, 1989), Vol. 3, p. 214] equilibria. The algorithm is extended to include the effects of collisions and drag, allowing rapid estimation of alpha particle loss in tokamaks. {copyright} {ital 1996 American Institute of Physics.}

White, R.B.; Goldston, R.J.; Redi, M.H.; Budny, R.V. [Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)] [Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)

1996-08-01

173

Mineralogical and geochemical aspects of mineral-induced disease  

SciTech Connect

Many minerals are known to cause disease following inhalation, including asbestos, silica, zeolites, and clays. The mineralogical properties that determine toxicity are not known, hindering effective risk assessment. Consequently, many minerals that do not pose risks are controlled excessively and many minerals that do pose risk remain uncontrolled. The authors are integrating mineralogy and biology in an interdisciplinary scientific investigation of the mechanisms of mineral-induced disease. The biological endpoints include the formation of ferruginous bodies and chemical signaling (e.g., production of cytokines or active oxygen species) by cells; the mineralogical variables include structure, composition, and surface properties. The authors are also determining what information about the biological reaction is preserved in the mineral surface.

Guthrie, G.; Raymond, R.; Saffiotti, U.; Aust, A. [Los Alamos National Lab., NM (United States); Mossman, B. [Univ. of Vermont, Burlington, VT (United States)

1996-04-01

174

Familial Alzheimer's disease modelling using induced pluripotent stem cell technology  

PubMed Central

Alzheimer’s disease (AD) is a progressive neurodegenerative disease in which patients exhibit gradual loss of memory that impairs their ability to learn or carry out daily tasks. Diagnosis of AD is difficult, particularly in early stages of the disease, and largely consists of cognitive assessments, with only one in four patients being correctly diagnosed. Development of novel therapeutics for the treatment of AD has proved to be a lengthy, costly and relatively unproductive process with attrition rates of > 90%. As a result, there are no cures for AD and few treatment options available for patients. Therefore, there is a pressing need for drug discovery platforms that can accurately and reproducibly mimic the AD phenotype and be amenable to high content screening applications. Here, we discuss the use of induced pluripotent stem cells (iPSCs), which can be derived from adult cells, as a method of recapitulation of AD phenotype in vitro. We assess their potential use in high content screening assays and the barriers that exist to realising their full potential in predictive efficacy, toxicology and disease modelling. At present, a number of limitations need to be addressed before the use of iPSC technology can be fully realised in AD therapeutic applications. However, whilst the use of AD-derived iPSCs in drug discovery remains a fledgling field, it is one with immense potential that is likely to reach fruition within the next few years.

Mohamet, Lisa; Miazga, Natalie J; Ward, Christopher M

2014-01-01

175

Self-Induced Polar Order of Active Brownian Particles in a Harmonic Trap  

NASA Astrophysics Data System (ADS)

Hydrodynamically interacting active particles in an external harmonic potential form a self-assembled fluid pump at large enough Péclet numbers. Here, we give a quantitative criterion for the formation of the pump and show that particle orientations align in the self-induced flow field in surprising analogy to ferromagnetic order where the active Péclet number plays the role of inverse temperature. The particle orientations follow a Boltzmann distribution ?(p)˜exp(Apz) where the ordering mean field A scales with the active Péclet number and polar order parameter. The mean flow field in which the particles' swimming directions align corresponds to a regularized Stokeslet with strength proportional to swimming speed. Analytic mean-field results are compared with results from Brownian dynamics simulations with hydrodynamic interactions included and are found to capture the self-induced alignment very well.

Hennes, Marc; Wolff, Katrin; Stark, Holger

2014-06-01

176

Effect of disease-induced mortality on structural network properties  

NASA Astrophysics Data System (ADS)

We study epidemic processes on complex networks, where infected nodes are either removed permanently or they can potentially recover. The process influences the localization of the infection by creating buffered zones, which in turn isolate large parts of the network. We show that there is an interesting interplay between the percentage and location of the removed population with the network structural integrity, even before reaching the critical point of total network disruption. The model can be used to determine the impact of disease-induced mortality to extinction of organisms, where destruction of the social structure can lead to loss of the species ability to recover.

Gallos, Lazaros; Fefferman, Nina

2013-03-01

177

Management of levodopa-induced dyskinesias in Parkinson's disease  

Microsoft Academic Search

\\u000a Abstract\\u000a   Long-term administration of levodopa in Parkinson's disease (PD) can cause motor complications such as dyskinesias and motor\\u000a response fluctuations. An increased risk is associated with more severity and younger age at onset of PD, longer duration\\u000a of treatment, and higher levodopa dose. Levodopa-induced dyskinesias (LID) consist of peak-dose dyskinesia, biphasic dyskinesia,\\u000a and off-period dystonia. The pathophysiology of LID includes

Kenichi Kashihara

2007-01-01

178

Advances in metal-induced oxidative stress and human disease.  

PubMed

Detailed studies in the past two decades have shown that redox active metals like iron (Fe), copper (Cu), chromium (Cr), cobalt (Co) and other metals undergo redox cycling reactions and possess the ability to produce reactive radicals such as superoxide anion radical and nitric oxide in biological systems. Disruption of metal ion homeostasis may lead to oxidative stress, a state where increased formation of reactive oxygen species (ROS) overwhelms body antioxidant protection and subsequently induces DNA damage, lipid peroxidation, protein modification and other effects, all symptomatic for numerous diseases, involving cancer, cardiovascular disease, diabetes, atherosclerosis, neurological disorders (Alzheimer's disease, Parkinson's disease), chronic inflammation and others. The underlying mechanism of action for all these metals involves formation of the superoxide radical, hydroxyl radical (mainly via Fenton reaction) and other ROS, finally producing mutagenic and carcinogenic malondialdehyde (MDA), 4-hydroxynonenal (HNE) and other exocyclic DNA adducts. On the other hand, the redox inactive metals, such as cadmium (Cd), arsenic (As) and lead (Pb) show their toxic effects via bonding to sulphydryl groups of proteins and depletion of glutathione. Interestingly, for arsenic an alternative mechanism of action based on the formation of hydrogen peroxide under physiological conditions has been proposed. A special position among metals is occupied by the redox inert metal zinc (Zn). Zn is an essential component of numerous proteins involved in the defense against oxidative stress. It has been shown, that depletion of Zn may enhance DNA damage via impairments of DNA repair mechanisms. In addition, Zn has an impact on the immune system and possesses neuroprotective properties. The mechanism of metal-induced formation of free radicals is tightly influenced by the action of cellular antioxidants. Many low-molecular weight antioxidants (ascorbic acid (vitamin C), alpha-tocopherol (vitamin E), glutathione (GSH), carotenoids, flavonoids, and other antioxidants) are capable of chelating metal ions reducing thus their catalytic activity to form ROS. A novel therapeutic approach to suppress oxidative stress is based on the development of dual function antioxidants comprising not only chelating, but also scavenging components. Parodoxically, two major antioxidant enzymes, superoxide dismutase (SOD) and catalase contain as an integral part of their active sites metal ions to battle against toxic effects of metal-induced free radicals. The aim of this review is to provide an overview of redox and non-redox metal-induced formation of free radicals and the role of oxidative stress in toxic action of metals. PMID:21414382

Jomova, Klaudia; Valko, Marian

2011-05-10

179

Animal models of beryllium-induced lung disease  

SciTech Connect

The Inhalation Toxicology Research Institute (ITRI) is conducting research to improve the understanding of chronic beryllium disease (CBD) and beryllium-induced lung cancer. Initial animal studies examined beagle dogs that inhaled BeO calcined at either 500 or 1000{degrees}C. At similar lung burdens, the 500{degrees}C BeO induced more severe and extensive granulomatous pneumonia, lymphocytic infiltration into the lung, and positive Be-specific lymphocyte proliferative responses in vitro than the 1000{degrees}C BeO. However, the progressive nature of human CBD was not duplicated. More recently, Strains A/J and C3H/HeJ mice were exposed to Be metal by inhalation. This produced a marked granulomatous pneumonia, diffuse infiltrates, and multifocal aggregates of interstitial lymphocytes with a pronounced T helper component and pulmonary in situ lymphocyte proliferation. With respect to lung cancer, at a mean lung burden as low as 17 pg Be/g lung, inhaled Be metal induced benign and/or malignant lung tumors in over 50% of male and female F344 rats surviving {ge}1 year on study. Substantial tumor multiplicity was found, but K-ras and p53 gene mutations were virtually absent. In mice, however, a lung burden of approximately 60 {mu}g ({approximately}300 {mu}g Be/g lung) caused only a slight increase in crude lung tumor incidence and multiplicity over controls in strain A/J mice and no elevated incidence in strain C3H mice. Taken together, this research program constitutes a coordinated effort to understand beryllium-induced lung disease in experimental animal models. 47 refs., 1 fig., 3 tabs.

Finch, G.L.; Hoover, M.D.; Hahn, F.F. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States)] [and others

1996-10-01

180

Animal models of beryllium-induced lung disease.  

PubMed Central

The inhalation Toxicology Research Institute (ITRI) is conducting research to improve the understanding of chronic beryllium disease (CBD) and beryllium-induced lung cancer. Initial animal studies examined beagle dogs that inhaled BeO calcined at either 500 or 1000 degrees C. At similar lung burdens, the 500 degrees C BeO induced more severe and extensive granulomatous pneumonia, lymphocytic infiltration into the lung, and positive Be-specific lymphocyte proliferative responses in vitro than the 1000 degrees C BeO. However, the progressive nature of human CBD was not duplicated. More recently, Strains A/J and C3H/Hej mice were exposed to Be metal by inhalation. This produced a marked granulomatous pneumonia, diffuse infiltrates, and multifocal aggregates of interstitial lymphocytes with a pronounced T helper component and pulmonary in situ lymphocyte proliferation. With respect to lung cancer, at a mean lung burden as low as 17 micrograms Be/g lung, inhaled Be metal induced benign and/or malignant lung tumors in over 50% of male and female F344 rats surviving > or = 1 year on study. Substantial tumor multiplicity was found, but K-ras and p53 gene mutations were virtually absent. In mice, however, a lung burden of approximately 60 micrograms (-300 micrograms Be/g lung) caused only a slight increase in crude lung tumor incidence and multiplicity over controls in strain A/J mice and no elevated incidence in strain C3H mice. Taken together, this research program constitutes a coordinated effort to understand beryllium-induced lung disease in experimental animal models.

Finch, G L; Hoover, M D; Hahn, F F; Nikula, K J; Belinsky, S A; Haley, P J; Griffith, W C

1996-01-01

181

Correlation of particle-induced displacement damage in silicon  

NASA Astrophysics Data System (ADS)

The effects of displacement damage caused in several types of silicon bipolar transistors by protons, deuterons, helium ions, and by 1-MeV-equivalent neutrons are considered. Measurements are compared to calculations of the nonionizing energy deposition in silicon as a function of particle type and energy. Measurements were made of displacement damage factors for 2N2222A and 2N2907A switching transistors, and for 2N3055, 2N6678, and 2N6547 power transistors, as a function of collector current using 3.7-175-MeV protons, 4.3-37-MeV deuterons, and 16.8-65-MeV helium ions. Long-term ionization effects on the value of the displacement damage factors were taken into account. In calculating the energy dependence of the nonionizing energy deposition, Rutherford, nuclear elastic, and nuclear inelastic interactions, and Lindhard energy partition were considered.

Summers, G. P.; Dale, C. J.; Burke, E. A.; Wolicki, E. A.; Marshall, P. W.

1987-12-01

182

Isomeric yield ratios in proton-, 3-, and alpha-particle-induced reactions on 197Au  

Microsoft Academic Search

Excitation functions and mean projected recoil-ion ranges of the isomeric nuclei produced in proton-, 3-, and alpha-particle-induced reactions on 197Au were measured by an activation technique for bombarding energies Ep<~50 MeV, and E 3He, alpha<~40 MeV. Isomeric yield ratios (sigmam\\/sigmag) were determined as a function of the incident particle energy. The experimental excitation functions and isomeric yield ratios were compared

Y. Nagame; K. Sueki; S. Baba; H. Nakahara

1990-01-01

183

Particle-induced amorphization of complex ceramics. Final report  

SciTech Connect

The crystalline-to-amorphous (c-a) phase transition is of fundamental importance. Particle irradiations provide an important, highly controlled means of investigating this phase transformation and the structure of the amorphous state. The interaction of heavy-particles with ceramics is complex because these materials have a wide range of structure types, complex compositions, and because chemical bonding is variable. Radiation damage and annealing can produce diverse results, but most commonly, single crystals become aperiodic or break down into a polycrystalline aggregate. The authors continued the studies of the transition from the periodic-to-aperiodic state in natural materials that have been damaged by {alpha}-recoil nuclei in the uranium and thorium decay series and in synthetic, analogous structures. The transition from the periodic to aperiodic state was followed by detailed x-ray diffraction analysis, in-situ irradiation/transmission electron microscopy, high resolution transmission electron microscopy, extended x-ray absorption fine structure spectroscopy/x-ray absorption near edge spectroscopy and other spectroscopic techniques. These studies were completed in conjunction with bulk irradiations that can be completed at Los Alamos National Laboratory or Sandia National Laboratories. Principal questions addressed in this research program included: (1) What is the process at the atomic level by which a ceramic material is transformed into a disordered or aperiodic state? (2) What are the controlling effects of structural topology, bond-type, dose rate, and irradiation temperature on the final state of the irradiated material? (3) What is the structure of the damaged material? (4) What are the mechanisms and kinetics for the annealing of interstitial and aggregate defects in these irradiated ceramic materials? (5) What general criteria may be applied to the prediction of amorphization in complex ceramics?

Ewing, R.C.; Wang, L.M.

1998-08-01

184

Foot-and-mouth disease virus particles contain replicase protein 3D.  

PubMed Central

An antibody against the Escherichia coli-expressed RNA polymerase of foot-and-mouth disease virus (FMDV) reacts with the virus in ELISA and radioimmunoprecipitation experiments and with a protein of the disrupted virus particle in an immunoblot analysis. Treatment of the virus with trypsin, which cleaves capsid protein VP1 and a 56-kDa polypeptide present in trace amount in the particles, reduces the level of the reaction in ELISA and radioimmunoprecipitation and eliminates the immunoblot reaction. Electron microscopy showed that only approximately 20% of the virus particles reacted with the anti-polymerase antibody, whereas most reacted with an antibody against the immunodominant G-H loop of the virus. In the presence of ammonium ions, the expressed polymerase degrades the RNA of the virus into molecules sedimenting at approximately 12 S, indicating that it can act as a hydrolytic as well as a polymerizing enzyme. Moreover, the RNA in trypsin-treated virus particles is degraded when incubated at 37 degrees C, suggesting that the cleaved 56-kDa protein still possesses hydrolytic activity. In addition, the anti-polymerase antibody, which inhibits the polymerase activity of the E. coli-expressed protein, also partially inhibits the hydrolytic activity of the previously described endonuclease of the virus particle, suggesting that this enzyme is identical with the polymerase or forms part of it. Images Fig. 2 Fig. 3

Newman, J F; Piatti, P G; Gorman, B M; Burrage, T G; Ryan, M D; Flint, M; Brown, F

1994-01-01

185

Acute cholestatic liver disease protects against glycerol-induced acute renal failure in the rat  

Microsoft Academic Search

Acute cholestatic liver disease protects against glycerol-induced acute renal failure in the rat.BackgroundIt is widely held that liver disease predisposes toward acute tubular necrosis. The present study examines the effect of acute cholestatic liver disease on the susceptibility to glycerol-induced acute tubular necrosis in the rat.MethodsAcute cholestatic liver disease was induced by ligation of the common bile duct, while the

Nelson Leung; Anthony J. Croatt; Jill J. Haggard; Joseph P. Grande; Karl A. Nath

2001-01-01

186

The mechanism of particles transport induced by electrostatic perturbation in tokamak  

SciTech Connect

Particle transport in tokamak devices due to wave-particle resonance induced diffusion is studied. The diffusion coefficient is derived both analytically using quasilinear theory, and numerically using a test particle code, and the obtained diffusion coefficient agrees with each other in its validity regime. Dependence of the diffusion coefficient on turbulence intensity, turbulence radial mode structures, and particle energy is investigated. It is found that the diffusion coefficient is proportional to the turbulence intensity, and the diffusion is maximized for E{sub t}?T{sub i}, and k{sub r}?{sub 0}?1. Here, E{sub t} is the test particle energy, T{sub i} is the thermal ion temperature, ?{sub 0} is the distance between neighboring mode rational surfaces, and 1/k{sub r} is the half width of the fine radial mode structure on each rational surface.

Feng, Zhichen; Qiu, Zhiyong; Sheng, Zhengmao [Department of Physics, Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)] [Department of Physics, Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

2013-12-15

187

NF-kB signaling blockade abolishes implant particle-induced osteoclastogenesis  

Microsoft Academic Search

In this study we investigated the effect of NF-kB signaling blockade on polymethylmethacrylate (PMMA) particle-induced osteoclastogenesis in vitro. We first established effective blockade of NF-kB activity as tested by electrophoretic mobility shift assays (EMSA). Particle-induced NF-kB activation in murine osteoclast precursor cells (CSF-1-dependent bone marrow macrophages) was markedly reduced by co-treatment of the cells with the NF-kB inhibitors N-tosyl-L-phenylalanine chloromethyl

John C. Clohisy; Teruhisa Hirayama; Elfaridah Frazier; Suk-Ku Han; Yousef Abu-Amer

2004-01-01

188

Modeling of alpha-particle-induced soft error rate in DRAM  

SciTech Connect

Alpha-particle-induced soft error in 256M DRAM was numerically investigated. A unified model for alpha-particle-induced charge collection and a soft-error-rate simulator (SERS) was developed. The author investigated the soft error rate of 256M DRAM and identified the bit-bar mode as one of dominant modes for soft error. In addition, for the first time, it was found that trench-oxide depth has a significant influence on soft error rate, and it should be determined by the tradeoff between soft error rate and cell-to-cell isolation characteristics.

Shin, H. [Ewha Womans Univ., Seoul (Korea, Republic of). Dept. of Electronic Engineering

1999-09-01

189

Parkinson's disease induced pluripotent stem cells with triplication of the alpha-synuclein locus  

Microsoft Academic Search

A major barrier to research on Parkinson's disease is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells from patients and differentiate them into neurons affected by disease. Triplication of SNCA, encoding alpha-synuclein, causes a fully penetrant, aggressive form of Parkinson's disease with dementia. alpha-Synuclein dysfunction is the critical pathogenic event in Parkinson's disease,

Michael J. Devine; Mina Ryten; Petr Vodicka; Alison J. Thomson; Tom Burdon; Henry Houlden; Fatima Cavaleri; Masumi Nagano; Nicola J. Drummond; Jan-Willem Taanman; Anthony H. Schapira; Katrina Gwinn; John Hardy; Patrick A. Lewis; Tilo Kunath

2011-01-01

190

Induced tunneling and localization for a quantum particle in tilted two-dimensional lattices  

NASA Astrophysics Data System (ADS)

We consider a quantum particle in tilted two-dimensional lattices in the tight-binding approximations. We show that for certain lattice geometries the particle can freely move across the lattice in the direction perpendicular to the vector of the static force. This effect is argued to be analog of the photon-induced tunneling in driven one-dimensional lattices. We calculate the particle dispersion relation by using a method based on the Bogoliubov-Mitropolskii averaging technique from the theory of dynamical systems. This dispersion relation draws the analogy with driven one-dimensional lattices further by eventually showing band collapses when a control parameter is varied.

Bulgakov, Evgeny N.; Kolovsky, Andrey R.

2014-01-01

191

Non-targeted effects induced by high LET charged particles  

NASA Astrophysics Data System (ADS)

Radiation-induced non-targeted response represents a paradigm shift in our understanding of the radiobiological effects of ionizing radiation in that extranuclear and extracellular effects may also contribute to the final biological consequences of exposure to low doses of radiation. Using the gpt delta transgenic mouse model, there is evidence that irradiation of a small area (1 cm by 1 cm) of the lower abdominal area of animals with a 5 Gy dose of X-rays induced cyclooxygenase-2 as well as deletion mutations in the out-of-field lung tissues of the animals. The mutation correlated with an increase in prostaglandin levels in the bystander lung tissues and with an increase in the level of 8-hydroxydeoxyguanosine (8-OHdG), an oxidative DNA damage marker. An increase in COX-2 level was also detected in the out-of-field lung tissues of animals similarly exposed to high LET argon and carbon ions accelerated at the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences in Japan. These results provide the first evidence that the COX-2 -related pathway, which is essential in mediating cellular inflammatory response, is the critical signaling link for the non-targeted, bystander phenomenon. A better understanding of the cellular and molecular mechanisms of the non-targeted, out of field phenomenon together with evidence of their occurrence in vivo will allow us to formulate a more accurate assessment of radiation risk.

Hei, Tom K.; Chai, Yunfei; Hamada, Nobuyuki; Kakinuma, Shizuko; Uchihori, Yukio

192

COX2 EXPRESSION INDUCED BY DIESEL PARTICLES INVOLVES CHROMATIN MODIFICATION AND DEGRADATION OF HDAC1  

Microsoft Academic Search

Cyclooxygenase-2 (COX-2) playsan important role inthe inflamma- tory response induced by physiologic and stress stimuli. Exposure todieselexhaustparticulatematter(DEP)hasbeen showntoinduce pulmonary inflammation and exacerbate asthma and chronic ob- structive pulmonary disease. DEP is a potent inducer of inflamma- tory reponses in human airway epithelial cells. The mechanism through which DEP inhalation induces inflammatory mediator ex- pression is not understood. In this report,

Dongsun Cao; Philip A. Bromberg; James M. Samet

2007-01-01

193

Mesoporous silica shell alleviates cytotoxicity and inflammation induced by colloidal silica particles.  

PubMed

Core-shell mesoporous silica (MPS) materials have been proven to perform multiple simultaneous functions in biological systems and they demonstrate a vast potential for applications in the medical arena. Exploring such extensive potential requires a meticulous evaluation of their interactions with cells. The aim of this study is to investigate the influence of MPS-shells on the viability and activation of human THP-1 macrophages by comparing core-shell MPS with colloidal silica particles. In the present study we find core-shell MPS particles with a solid colloidal silica core and a thin MPS-shell deliver significantly less cytotoxicity than their nonporous counterparts and induce lower expression and release of the pro-inflammatory cytokines in macrophages. Moreover, core-shell MPS particles show no effect on the activation of mitogen-activated protein kinases (MAPKs), while colloidal silica particles do activate MAPKs under identical conditions. The corona of core-shell MPS particles is composed of a greater amount and variety of proteins as compared with colloidal silica particles. The abundant protein composition of the corona may inhibit the cellular toxicity by masking surface silanol groups at the MPS-cellular interface. In conclusion, the MPS-shell significantly alleviates both cytotoxicity and immune responses induced by colloidal silica particles while greatly improving the biocompatibility of colloidal silica materials. PMID:24513963

Wang, Jie; Shen, Yuqing; Bai, Ling; Lv, Dan; Zhang, Aifeng; Miao, Fengqin; Tang, Meng; Zhang, Jianqiong

2014-04-01

194

Induced pluripotent stem cell therapies for retinal disease  

PubMed Central

Purpose of review: This review will discuss how recent advances with induced pluripotent stem (iPS) cells have brought the science of stem cell biology much closer to clinical application for patients with retinal degeneration. Recent findings: The ability to generate embryonic stem (ES) cells by reprogramming DNA taken from adult cells was demonstrated by the cloning of Dolly the sheep by somatic cell nuclear transfer over ten years ago. Recently it has been shown that adult cells can be reprogrammed directly, without the need for a surrogate oocyte through the generation of induced pluripotent stem (iPS) cells. The method of reprogramming has since been optimised to avoid the use of retroviruses, making the process considerably safer. Last year human iPS cells were isolated from an 80 year old patient with neurodegenerative disease and differentiated into neurons in vitro. Summary: For stem cell therapies, the retina has the optimal combination of ease of surgical access, combined with an ability to observe transplanted cells directly through the clear ocular media. The question now is which retinal diseases are most appropriate targets for clinical trials using iPS cell approaches.

Comyn, Oliver; Lee, Edward; MacLaren, Robert E

2010-01-01

195

Placental Induced Growth Factor (PIGf) in Coronary Artery Disease  

NASA Technical Reports Server (NTRS)

Our previous studies on normal human lymphocytes have shown a five-fold increase (p less than 0.001) in angiogenic inducers such as Placental Induced Growth Factor (PIGf) in physiologically stressful environments such as modeled microgravity, a space analog. This suggests de-regulation of cardiovascular signalling pathways indicated by upregulation of PIGf. In the current study, we measured PIGf in the plasma of 33 patients with and without coronary artery disease (CAD) to investigate whether such disease is associated with increased levels of PIGf. A control consisting of 31 sex matched apparently healthy subjects was also included in the study. We observed that the levels of PIGf in CAD patients were significantly increased compared to those in healthy control subjects (p less than 0.001) and usually increased beyond the clinical threshold level (greater than 27ng/L). The mechanisms leading to up-regulation of angiogenic factors and the adaptation of organisms to stressful environments such as isolation, high altitude, hypoxia, ischemia, microgravity, increased radiation, etc are presently unknown and require further investigation in spaceflight and these other physiologically stressed environments.

Sundaresan, Alamelu; Carabello, Blaise; Mehta, Satish; Schlegel, Todd; Pellis, Neal; Ott, Mark; Pierson, Duane

2010-01-01

196

Oxidatively induced DNA damage: mechanisms, repair and disease.  

PubMed

Endogenous and exogenous sources cause oxidatively induced DNA damage in living organisms by a variety of mechanisms. The resulting DNA lesions are mutagenic and, unless repaired, lead to a variety of mutations and consequently to genetic instability, which is a hallmark of cancer. Oxidatively induced DNA damage is repaired in living cells by different pathways that involve a large number of proteins. Unrepaired and accumulated DNA lesions may lead to disease processes including carcinogenesis. Mutations also occur in DNA repair genes, destabilizing the DNA repair system. A majority of cancer cell lines have somatic mutations in their DNA repair genes. In addition, polymorphisms in these genes constitute a risk factor for cancer. In general, defects in DNA repair are associated with cancer. Numerous DNA repair enzymes exist that possess different, but sometimes overlapping substrate specificities for removal of oxidatively induced DNA lesions. In addition to the role of DNA repair in carcinogenesis, recent evidence suggests that some types of tumors possess increased DNA repair capacity that may lead to therapy resistance. DNA repair pathways are drug targets to develop DNA repair inhibitors to increase the efficacy of cancer therapy. Oxidatively induced DNA lesions and DNA repair proteins may serve as potential biomarkers for early detection, cancer risk assessment, prognosis and for monitoring therapy. Taken together, a large body of accumulated evidence suggests that oxidatively induced DNA damage and its repair are important factors in the development of human cancers. Thus this field deserves more research to contribute to the development of cancer biomarkers, DNA repair inhibitors and treatment approaches to better understand and fight cancer. PMID:22293091

Dizdaroglu, Miral

2012-12-31

197

Derivation of Induced Pluripotent Stem Cells for Human Disease Modeling  

PubMed Central

The successful derivation of human induced pluripotent stem cells (hiPSCs) by de-differentiation of somatic cells offers significant potential to overcome obstacles in the field of cardiovascular disease. hiPSC derivatives offer incredible potential for new disease models and regenerative medicine therapies. However, many questions remain regarding the optimal starting materials and methods to enable safe, efficient derivation of hiPSCs suitable for clinical applications. Initial reprogramming experiments were carried out using lentiviral or retroviral gene delivery methods. More recently, various non-viral methods that avoid permanent and random transgene insertion have emerged as alternatives. These include transient DNA transfection approaches using transposons or minicircle plasmids, protein transduction approaches, and RNA transfection approaches. In addition, several small molecules have been found to significantly augment iPSC derivation efficiency, allowing the use of a fewer number of genes during pluripotency induction. Here, we review these various methods for the derivation of hiPSCs, focusing on their ultimate clinical applicability, with an emphasis on their potential for use as cardiovascular therapies and disease modeling platforms.

Narsinh, Kamileh; Narsinh, Kazim H.; Wu, Joseph C.

2011-01-01

198

CAG expansion induces nucleolar stress in polyglutamine diseases  

PubMed Central

The cell nucleus is a major site for polyglutamine (polyQ) toxicity, but the underlying mechanisms involved have yet been fully elucidated. Here, we report that mutant RNAs that carry an expanded CAG repeat (expanded CAG RNAs) induce apoptosis by activating the nucleolar stress pathway in both polyQ patients and transgenic animal disease models. We showed that expanded CAG RNAs interacted directly with nucleolin (NCL), a protein that regulates rRNA transcription. Such RNA–protein interaction deprived NCL of binding to upstream control element (UCE) of the rRNA promoter, which resulted in UCE DNA hypermethylation and subsequently perturbation of rRNA transcription. The down-regulation of rRNA transcription induced nucleolar stress and provoked apoptosis by promoting physical interaction between ribosomal proteins and MDM2. Consequently, p53 protein was found to be stabilized in cells and became concentrated in the mitochondria. Finally, we showed that mitochondrial p53 disrupted the interaction between the antiapoptotic protein, Bcl-xL, and the proapoptotic protein, Bak, which then caused cytochrome c release and caspase activation. Our work provides in vivo evidence that expanded CAG RNAs trigger nucleolar stress and induce apoptosis via p53 and describes a polyQ pathogenic mechanism that involves the nucleolus.

Tsoi, Ho; Lau, Terrence Chi-Kong; Tsang, Suk-Ying; Lau, Kwok-Fai; Chan, Ho Yin Edwin

2012-01-01

199

Acute Chagas Disease Induces Cerebral Microvasculopathy in Mice  

PubMed Central

Cardiomyopathy is the main clinical form of Chagas disease (CD); however, cerebral manifestations, such as meningoencephalitis, ischemic stroke and cognitive impairment, can also occur. The aim of the present study was to investigate functional microvascular alterations and oxidative stress in the brain of mice in acute CD. Acute CD was induced in Swiss Webster mice (SWM) with the Y strain of Trypanosoma cruzi (T. cruzi). Cerebral functional capillary density (the number of spontaneously perfused capillaries), leukocyte rolling and adhesion and the microvascular endothelial-dependent response were analyzed over a period of fifteen days using intravital video-microscopy. We also evaluated cerebral oxidative stress with the thiobarbituric acid reactive species TBARS method. Compared with the non-infected group, acute CD significantly induced cerebral functional microvascular alterations, including (i) functional capillary rarefaction, (ii) increased leukocyte rolling and adhesion, (iii) the formation of microvascular platelet-leukocyte aggregates, and (iv) alteration of the endothelial response to acetylcholine. Moreover, cerebral oxidative stress increased in infected animals. We concluded that acute CD in mice induced cerebral microvasculopathy, characterized by a reduced incidence of perfused capillaries, a high number of microvascular platelet-leukocyte aggregates, a marked increase in leukocyte-endothelium interactions and brain arteriolar endothelial dysfunction associated with oxidative stress. These results suggest the involvement of cerebral microcirculation alterations in the neurological manifestations of CD.

Nisimura, Lindice Mitie; Estato, Vanessa; de Souza, Elen Mello; Reis, Patricia A.; Lessa, Marcos Adriano; Castro-Faria-Neto, Hugo Caire; Pereira, Mirian Claudia de Souza; Tibirica, Eduardo; Garzoni, Luciana Ribeiro

2014-01-01

200

ULTRAFINE CARBON PARTICLES INDUCE INTERLEUKIN-8 GENE TRANSCRIPTION AND P38 MAPK ACTIVATION IN NORMAL BRONCHIAL EPITHELIAL CELLS  

EPA Science Inventory

Epidemiological studies suggest that ultrafine particles contribute to particulate matter-induced adverse health effects. Interleukin (IL)-8 is an important proinflammatory cytokine in the human lung that is induced in respiratory cells exposed to a variety of environmental insul...

201

Moving force of metal particle migration induced by laser irradiation in borosilicate glass.  

PubMed

We optically manipulated a metal particle in borosilicate glass. The glass in the neighborhood of the laser-heated metal particle softened; hence, the metal particle was able to migrate in the glass. In this letter, the driving force of the metal particle toward the light source in the glass provided by laser illumination was investigated. The variation in the surface tension of the glass at the interface between the glass and the metal particle induced by the temperature gradient was calculated via a numerical temperature calculation. It was found that the temperature at the laser-illuminated surface of a stainless-steel particle with a radius of 40 ?m was ~320 K higher than that on the nonilluminated side. The force applied to the metal particle from the surrounding glass was calculated to be ~100 ?N, which was approximately equal to the viscous resistance force. In addition, the experimental and numerically calculated speeds of the moving particle, which was measured while varying the laser power, are discussed. PMID:23938809

Hidai, Hirofumi; Matsushita, Makoto; Matsusaka, Souta; Chiba, Akira; Morita, Noboru

2013-08-12

202

DIESEL EXHAUST PARTICLE INDUCED GENE EXPRESSION CHANGES IN A MURINE MUCOSAL SENSITIZATION MODEL  

EPA Science Inventory

Studies in humans and animals have shown diesel exhaust particles (DEP) can act as an immunological adjuvant to enhance the development of allergic lung disease and this effect is influenced by the chemical composition of the DEP. The adjuvancy of NIST SRM 2975 (NDEP) generated...

203

Light flash phenomena induced by HzE particles  

NASA Technical Reports Server (NTRS)

Astronauts and Apollo and Skylab missions have reported observing a variety of visual phenomena when their eyes are closed and adapted to darkness. These phenomena have been collectively labelled as light flashes. Visual phenomena which are similar in appearance to those observed in space have been demonstrated at the number of accelerator facilities by expressing the eyes of human subjects to beams of various types of radiation. In some laboratory experiments Cerenkov radiation was found to be the basis for the flashes observed while in other experiments Cerenkov radiation could apparently be ruled out. Experiments that differentiate between Cerenkov radiation and other possible mechanisms for inducing visual phenomena was then compared. The phenomena obtained in the presence and absence of Cerenkov radiation were designed and conducted. A new mechanism proposed to explain the visual phenomena observed by Skylab astronauts as they passed through the South Atlantic Anomaly, namely nuclear interactions in and near the sensitive layer of the retina, is covered. Also some studies to search for similar transient effects of space radiation on sensors and microcomputer memories are described.

Mcnulty, P. J.; Pease, V. P.

1980-01-01

204

Dose response of micronuclei induced by combination radiation of ?-particles and ?-rays in human lymphoblast cells.  

PubMed

Combination radiation is a real situation of both nuclear accident exposure and space radiation environment, but its biological dosimetry is still not established. This study investigated the dose-response of micronuclei (MN) induction in lymphocyte by irradiating HMy2.CIR lymphoblast cells with ?-particles, ?-rays, and their combinations. Results showed that the dose-response of MN induced by ?-rays was well-fitted with the linear-quadratic model. But for ?-particle irradiation, the MN induction had a biphasic phenomenon containing a low dose hypersensitivity characteristic and its dose response could be well-stimulated with a state vector model where radiation-induced bystander effect (RIBE) was involved. For the combination exposure, the dose response of MN was similar to that of ?-irradiation. However, the yield of MN was closely related to the sequence of irradiations. When the cells were irradiated with ?-particles at first and then ?-rays, a synergistic effect of MN induction was observed. But when the cells were irradiated with ?-rays followed by ?-particles, an antagonistic effect of MN was observed in the low dose range although this combination radiation also yielded a synergistic effect at high doses. When the interval between two irradiations was extended to 4h, a cross-adaptive response against the other irradiation was induced by a low dose of ?-rays but not ?-particles. PMID:23313503

Ren, Ruiping; He, Mingyuan; Dong, Chen; Xie, Yuexia; Ye, Shuang; Yuan, Dexiao; Shao, Chunlin

2013-01-01

205

Cocaine-induced midline destructive lesions - an autoimmune disease?  

PubMed

In Europe it is estimated that around 13million of adults (15-64years) have used cocaine at least once in their lifetime. The most frequently used route of administration for the drug is intranasal inhalation, or "snorting", and thus the adverse effects of cocaine on the nasal tract are very common. Habitual nasal insufflations of cocaine may cause mucosal lesions, and if cocaine use becomes chronic and compulsive, progressive damage of the mucosa and perichondrium leads to ischemic necrosis of septal cartilage and perforation of the nasal septum. Occasionally, cocaine-induced lesions cause extensive destruction of the osteocartilaginous structures of nose, sinuses and palate that can mimic other diseases such as tumors, infections, and immunological diseases. Thorough diagnostic workup, including endoscopic, radiologic, histopathologic and serologic testing is imperative to arrive at the proper diagnosis and to initiate appropriate local and systemic treatment. Positive antineutrophil cytoplasmic antibody (ANCA) test results may be found in an unexpectedly large proportion of patients with CIMDL. In several instances their lesions are clinically indistinguishable from granulomatosis with polyangiitis (Wegener's) limited to the upper respiratory tract. CIMDL seem to be the result of a necrotizing inflammatory tissue response triggered by cocaine abuse in a subset of patients predisposed to produce ANCA, particularly those reacting with HNE. The presence of these HNE-ANCA seems to promote or define the disease phenotype. CIMDL do not respond well to immunosuppressive therapy. Only the consistent removal of persistent stimuli of autoantibody production (cocaine, bacterial superinfections) can halt the disease process, prevent the progression of the lesions and promise success of surgical repair procedures. PMID:22940554

Trimarchi, M; Bussi, M; Sinico, R A; Meroni, Pierluigi; Specks, U

2013-02-01

206

VPg gene amplification correlates with infective particle formation in foot-and-mouth disease virus.  

PubMed Central

In order to analyze the function of VPg amplification in aphthoviruses, we have undertaken the first mutational analysis of the repetitive VPg-coding region using an improved foot-and-mouth disease virus (FMDV) cDNA clone from which infective viral RNA was synthesized. A set of VPg mutants was constructed by site-directed mutagenesis which includes different VPg deletion mutations, a VPg insertion mutation, and amino acid residue replacement mutations that interfere with binding of the VPg protein to the viral RNA and with its proteolytic processing. Our results revealed that an amazing flexibility in the number of VPgs is tolerated in FMDV. Optimal viability is given when three VPgs are encoded. Deletion as well as insertion of one VPg gene still resulted in infective particle production. Infective particle formation was observed as long as one VPg remained intact. No obvious differences in the individual VPg molecules with regard to their promoting viral RNA synthesis were observed, indicating that all three VPgs can act equally in FMDV replication. Mutant polyprotein processing was comparable to that of the wild-type virus. However, VPg mutants showed reduced viral RNA synthesis levels after infection. The levels of viral RNA synthesis and infective particle formation were found to correlate with the number of functional VPgs left in the mutant virus. These findings suggest a direct VPg gene dosage effect on viral RNA synthesis, with a secondary effect on infective particle formation. Images

Falk, M M; Sobrino, F; Beck, E

1992-01-01

207

CARDIOVASCULAR FUNCTIONAL, CELLULAR, AND MOLECULAR EFFECTS INDUCED BY EMISSION SOURCE PARTICLE CONSTITUENTS  

EPA Science Inventory

Epidemiological, clinical and toxicological studies have demonstrated the ability of ambient PM and certain emission source particles to altered autonomic control of the heart and induce arrhythmia. A number of hypotheses have been proposed to explain these effects such as direct...

208

Influence of resistivity on energetic trapped particle-induced internal kink modes  

SciTech Connect

The influence of resistivity on energetic trapped particle-induced internal kink modes, dubbed ''fishbones'' in the literature, explored. A general dispersion relation, which recovers the ideal theory in its appropriate limit, is derived and analyzed. Implications of the theory for present generation fusion devices such as the Joint European Torus are discussed. 8 refs., 2 figs.

Biglari, H.; Chen, L.

1986-01-01

209

Particle Induced X-Ray Emission for Quantitative Trace-Element Analysis Using the Eindhoven Cyclotron.  

National Technical Information Service (NTIS)

Development of a multi-elemental trace analysis technique using PIXE (Particle Induced X-ray Emission), was started almost five years ago at the Eindhoven University of Technology, in the Cyclotron Applications Group of the Physics Department. The aim of ...

H. Kivits

1980-01-01

210

A new setup for elastic recoil analysis using ion induced electron emission for particle identification  

Microsoft Academic Search

We describe a new setup for elastic recoil detection analysis (ERDA) using our recently developed particle identification method. Before the ions and elastic recoil atoms from the target reach a silicon surface barrier detector for energy analysis, they penetrate a set of thin foils (e.g. carbon). The ion induced electron emission yield from the foils depends on the nuclear charge

E. Steinbauer; O. Benka; M. Steinbatz

1998-01-01

211

The merits of particle induced X-ray emission in revealing painting techniques  

Microsoft Academic Search

Particle induced X-ray emission (PIXE) at the external proton beam has proved ideal to study individual techniques of creating art objects. In particular, PIXE is suitable for examining paintings because of the low level of background produced by organic components like binders and paper backings. Thus, traces of pigments as deposited from pens on cardboard can be identified by this

C. Neelmeijer; M. Mäder

2002-01-01

212

DIESEL AND CARBON PARTICLES ENHANCE HOUSE DUST MITE-INDUCED PULMONARY HYPERSENSITIVITY IN BROWN NORWAY RATS  

EPA Science Inventory

Diesel and Carbon Particles Enhance House Dust Mite-Induced Pulmonary Hypersensitivity in Brown Norway Rats. P. Singh1, M.J. Daniels2, D. Winsett2, J. Richards2, K. Crissman2, M. Madden2 and M.I. Gilmour2. 1NCSU, Raleigh, NC and 2 USEPA, Research Triangle Park, NC. Ep...

213

The motion of large bottom particles (cobbles) in a wave-induced oscillatory flow  

Microsoft Academic Search

The purpose of this paper is to present the results of a series of experiments aimed at better understanding the dynamics of the motion of large bottom particles (cobbles) in a wave-induced oscillatory flow. This problem is closely related to the motion of cobbles along the bottom in an oscillatory flow such as occurs in coastal waters beyond the region

S. I. Voropayev; J. Roney; D. L. Boyer; H. J. S. Fernando; W. N. Houston

1998-01-01

214

Drug-induced autoimmune liver disease: A diagnostic dilemma of an increasingly reported disease.  

PubMed

The aetiology of autoimmune hepatitis (AIH) is uncertain but the disease can be triggered in susceptible patients by external factors such as viruses or drugs. AIH usually develops in individuals with a genetic background mainly consisting of some risk alleles of the major histocompatibility complex (HLA). Many drugs have been linked to AIH phenotypes, which sometimes persist after drug discontinuation, suggesting that they awaken latent autoimmunity. At least three clinical scenarios have been proposed that refers to drug- induced autoimmune liver disease (DIAILD): AIH with drug-induced liver injury (DILI); drug induced-AIH (DI-AIH); and immune mediated DILI (IM-DILI). In addition, there are instances showing mixed features of DI-AIH and IM-DILI, as well as DILI cases with positive autoantibodies. Histologically distinguishing DILI from AIH remains a challenge. Even more challenging is the differentiation of AIH from DI-AIH mainly relying in histological features; however, a detailed standardised histologic evaluation of large cohorts of AIH and DI-AIH patients would probably render more subtle features that could be of help in the differential diagnosis between both entities. Growing information on the relationship of drugs and AIH is being available, being drugs like statins and biologic agents more frequently involved in cases of DIAILD. In addition, there is some evidence on the fact that patients diagnosed with DIAILD may have had a previous episode of hepatotoxicity. Further collaborative studies in DIAILD will strengthen the knowledge and understanding of this intriguing and complex disorder which might represent different phenotypes across the spectrum of disease. PMID:24799984

Castiella, Agustin; Zapata, Eva; Lucena, M Isabel; Andrade, Raúl J

2014-04-27

215

Drug-induced autoimmune liver disease: A diagnostic dilemma of an increasingly reported disease  

PubMed Central

The aetiology of autoimmune hepatitis (AIH) is uncertain but the disease can be triggered in susceptible patients by external factors such as viruses or drugs. AIH usually develops in individuals with a genetic background mainly consisting of some risk alleles of the major histocompatibility complex (HLA). Many drugs have been linked to AIH phenotypes, which sometimes persist after drug discontinuation, suggesting that they awaken latent autoimmunity. At least three clinical scenarios have been proposed that refers to drug- induced autoimmune liver disease (DIAILD): AIH with drug-induced liver injury (DILI); drug induced-AIH (DI-AIH); and immune mediated DILI (IM-DILI). In addition, there are instances showing mixed features of DI-AIH and IM-DILI, as well as DILI cases with positive autoantibodies. Histologically distinguishing DILI from AIH remains a challenge. Even more challenging is the differentiation of AIH from DI-AIH mainly relying in histological features; however, a detailed standardised histologic evaluation of large cohorts of AIH and DI-AIH patients would probably render more subtle features that could be of help in the differential diagnosis between both entities. Growing information on the relationship of drugs and AIH is being available, being drugs like statins and biologic agents more frequently involved in cases of DIAILD. In addition, there is some evidence on the fact that patients diagnosed with DIAILD may have had a previous episode of hepatotoxicity. Further collaborative studies in DIAILD will strengthen the knowledge and understanding of this intriguing and complex disorder which might represent different phenotypes across the spectrum of disease

Castiella, Agustin; Zapata, Eva; Lucena, M Isabel; Andrade, Raul J

2014-01-01

216

Fluctuation-induced transport of two coupled particles: Effect of the interparticle interaction  

NASA Astrophysics Data System (ADS)

We consider a system of two coupled particles fluctuating between two states, with different interparticle interaction potentials and particle friction coefficients. An external action drives the interstate transitions that induces reciprocating motion along the internal coordinate x (the interparticle distance). The system moves unidirectionally due to rectification of the internal motion by asymmetric friction fluctuations and thus operates as a dimeric motor that converts input energy into net movement. We focus on how the law of interaction between the particles affects the dimer transport and, in particular, the role of thermal noise in the motion inducing mechanism. It is argued that if the interaction potential behaves at large distances as x?, depending on the value of the exponent ?, the thermal noise plays a constructive (? > 2), neutral (? = 2), or destructive (? < 2) role. In the case of ? = 1, corresponding piecewise linear potential profiles, an exact solution is obtained and discussed in detail.

Makhnovskii, Yurii A.; Rozenbaum, Viktor M.; Sheu, Sheh-Yi; Yang, Dah-Yen; Trakhtenberg, Leonid I.; Lin, Sheng Hsien

2014-06-01

217

Induced velocities of grains embedded in a turbulent gas. [test particle theory application to protostellar clouds  

NASA Technical Reports Server (NTRS)

A theory is presented for the dynamics of dust particles in an incompressible turbulent fluid. Grain-gas coupling occurs through friction forces that are proportional to the mean grain velocity relative to the gas. This test particle theory is applied to the case of Kolmogoroff spectrum in a protostellar cloud. The mean turbulence induced grain velocity and the mean turbulent relative velocity of two grains are calculated. Whereas the former should determine the dust scale height, grain-grain collisions are influenced by the latter. For a reasonable strength of turbulence, the mean induced relative velocity of two particles turns out to be at least as large as the corresponding terminal velocity difference during gravitational settling.

Voelk, H. J.; Morfill, G.; Roeser, S.; Jones, F. C.

1978-01-01

218

Fluctuation-induced transport of two coupled particles: Effect of the interparticle interaction.  

PubMed

We consider a system of two coupled particles fluctuating between two states, with different interparticle interaction potentials and particle friction coefficients. An external action drives the interstate transitions that induces reciprocating motion along the internal coordinate x (the interparticle distance). The system moves unidirectionally due to rectification of the internal motion by asymmetric friction fluctuations and thus operates as a dimeric motor that converts input energy into net movement. We focus on how the law of interaction between the particles affects the dimer transport and, in particular, the role of thermal noise in the motion inducing mechanism. It is argued that if the interaction potential behaves at large distances as x(?), depending on the value of the exponent ?, the thermal noise plays a constructive (? > 2), neutral (? = 2), or destructive (? < 2) role. In the case of ? = 1, corresponding piecewise linear potential profiles, an exact solution is obtained and discussed in detail. PMID:24907991

Makhnovskii, Yurii A; Rozenbaum, Viktor M; Sheu, Sheh-Yi; Yang, Dah-Yen; Trakhtenberg, Leonid I; Lin, Sheng Hsien

2014-06-01

219

Disease-Dependent Local IL-10 Production Ameliorates Collagen Induced Arthritis in Mice  

PubMed Central

Rheumatoid arthritis (RA) is a chronic destructive autoimmune disease characterised by periods of flare and remission. Today’s treatment is based on continuous immunosuppression irrespective of the patient’s inflammatory status. When the disease is in remission the therapy is withdrawn but withdrawal attempts often results in inflammatory flares, and re-start of the therapy is commenced when the inflammation again is prominent which leads both to suffering and increased risk of tissue destruction. An attractive alternative treatment would provide a disease-regulated therapy that offers increased anti-inflammatory effect during flares and is inactive during periods of remission. To explore this concept we expressed the immunoregulatory cytokine interleukin (IL)-10 gene under the control of an inflammation dependent promoter in a mouse model of RA - collagen type II (CII) induced arthritis (CIA). Haematopoetic stem cells (HSCs) were transduced with lentiviral particles encoding the IL-10 gene (LNT-IL-10), or a green fluorescence protein (GFP) as control gene (LNT-GFP), driven by the inflammation-dependent IL-1/IL-6 promoter. Twelve weeks after transplantation of transduced HSCs into DBA/1 mice, CIA was induced. We found that LNT-IL-10 mice developed a reduced severity of arthritis compared to controls. The LNT-IL-10 mice exhibited both increased mRNA expression levels of IL-10 as well as increased amount of IL-10 produced by B cells and non-B APCs locally in the lymph nodes compared to controls. These findings were accompanied by increased mRNA expression of the IL-10 induced suppressor of cytokine signalling 1 (SOCS1) in lymph nodes and a decrease in the serum protein levels of IL-6. We also found a decrease in both frequency and number of B cells and serum levels of anti-CII antibodies. Thus, inflammation-dependent IL-10 therapy suppresses experimental autoimmune arthritis and is a promising candidate in the development of novel treatments for RA.

Jirholt, Pernilla; Tengvall, Sara; Lidberg, Ulf; van den Berg, Wim B.; van de Loo, Fons A.; Gjertsson, Inger

2012-01-01

220

Purification, characterization and serological detection of virus-like particles associated with banana bunchy top disease in Australia  

Microsoft Academic Search

Isometric virus-like particles, 18 nm in diameter, have been isolated from banana (Musa spp.) affected by bunchy top disease in Australia. Banana bunchy top disease-associated virus-like particles (BBTV) banded as a single component with buoyant density of 1-28 to 1.29 g\\/ml in Cs2SO4 and sedimented at about 46S in isokinetic sucrose density gradients. The A260\\/.42S 0 of purified preparations was

John E. Thomas; Ralf G. Dietzgen

1991-01-01

221

Alpha particle induced gamma yields in uranium hexafluoride  

NASA Astrophysics Data System (ADS)

Fluorine has a relatively large (?,n) production cross-section in the MeV range, the energy range of interest for special nuclear materials. In the uranium fuel cycle enriched UF6 in particular is a reasonably prolific source of (?,n) neutrons because along with 235U, 234U becomes enriched and it has a relatively short half-life. This enables the mass content of storage cylinders containing UF6 to be verified by neutron counting methods. In association with such measurements high resolution gamma-ray spectrometry (HRGS) measurements using a high-purity Ge detector are often undertaken to determine the 235U enrichment based off the intensity of the direct 186 keV line. The specific (?,n) neutron production, neutrons per second per gram of U, is sensitive to the relative isotopic composition, particularly the 234U concentration, and the traditional gross neutron counting approach is needed to quantitatively interpret the data. In addition to F(?,n) neutrons, ?-induced reaction ?-rays are generated, notably at 110, 197, 582, 891, 1236 and 1275 keV. If one could observe 19F(?,x?) gamma-lines in the HRGS spectra the thought was that perhaps the ?-activity could be estimated directly, and in turn the 234U abundance obtained. For example, by utilizing the ratio of the detected 197-186 keV full energy peaks. However, until now there has been no readily available estimate of the expected strength of the reaction gamma-rays nor any serious consideration as to whether they might be diagnostic or not. In this work we compute the thick target yields of the chief reaction gamma-rays in UF6 using published thin target data. Comparisons are made to the neutron production rates to obtain ?/n estimates, and also to the 235U decay line at 186 keV which we take as a fiducial line. It is shown that the reaction gamma-rays are produced but are far too weak for practical safeguards purposes. Now that the underlying numerical data is readily available however, it can be used to support neutron and gamma production calculations in other fluorine compounds, for example impure plutonium reference materials where fluorine may be present only at the parts per million by weight level yet still present a serious nuisance addition to the neutron production rate.

Croft, Stephen; Swinhoe, Martyn T.; Miller, Karen A.

2013-01-01

222

Frequency-dependent behaviors of individual microscopic particles in an optically induced dielectrophoresis device  

PubMed Central

An optoelectronic microdevice is set up to drive single microparticles and a maximum synchronous velocity (MS-velocity) spectrum method is proposed for quantifying the frequency-dependent behaviors of individual neutral microparticles from 40 kHz to 10 MHz. Dielectrophoretic behaviors of three types of microparticles are investigated under the optically induced nonuniform electric field. Different MS-velocity spectra for the three different particles are experimentally found. Numerical calculations for the MS-velocity spectra of polystyrene microparticles are performed. The spectrum of the MS-velocities for a specific particle is mainly determined by the particle inherent property and the electric characteristics of the device. Moreover the experimental and the numerical MS-velocity spectra are compared to be accordant. Based on the dielectrophoretic (DEP) behaviors of the particles under a nonuniform electric field, microparticles can be finely characterized or distinguished according to their distinct MS-velocity spectra.

Zhu, Xiaolu; Yi, Hong; Ni, Zhonghua

2010-01-01

223

Particle irradiation induces FGF2 expression in normal human lens cells  

NASA Technical Reports Server (NTRS)

Particle Irradiation Induces FGF2 Expression in Normal Human Lens Cells. Particle radiations, including both proton and helium-ion beams, have been used to successfully treat choroidal melanoma, but with the complication of radiation-induced cataract. We have investigated a role for radiation-induced changes in the expression of basic fibroblast growth factor (FGF2) gene expression as part of the mechanism(s) underlying lens cell injury associated with cataract. Normal human lens epithelial (HLE) cells were cultured in vitro on extracellular matrix (ECM) originated from bovine corneal endothelial cells. This study reports evidence for rapid but transient induction of FGF2 transcripts, an increase of between 5- and 8-fold, within 0.5 h after exposure to particle radiation, followed by another wave of increased transcription at 2-3 h postirradiation. Immunofluorescence results confirm the enhanced levels of FGF2 protein rapidly after exposure to protons or helium ions, followed by another wave of increased activity unique to helium at 6 h postirradiation. This second wave of increased immunoreactivity was not observed in the proton-irradiated samples. Total FGF2 protein analysis after helium-ion exposures shows induced expression of three FGF2 isoforms, with an increase of up to 2-fold in the 18-kDa low-molecular-weight species. Studies of the effects of protons on individual FGF2 protein isoforms are in progress. Several mechanisms involving a role for FGF2 in radiation-induced cataract are discussed.

Chang, P. Y.; Bjornstad K, A.; Chang, E.; McNamara, M.; Barcellos-Hoff, M. H.; Lin, S. P.; Aragon, G.; Polansky, J. R.; Lui, G. M.; Blakely, E. A.

2000-01-01

224

Experimental determination of the respiratory tract deposition of diesel combustion particles in patients with chronic obstructive pulmonary disease  

PubMed Central

Background Air pollution, mainly from combustion, is one of the leading global health risk factors. A susceptible group is the more than 200 million people worldwide suffering from chronic obstructive pulmonary disease (COPD). There are few data on lung deposition of airborne particles in patients with COPD and none for combustion particles. Objectives To determine respiratory tract deposition of diesel combustion particles in patients with COPD during spontaneous breathing. Methods Ten COPD patients and seven healthy subjects inhaled diesel exhaust particles generated during idling and transient driving in an exposure chamber. The respiratory tract deposition of the particles was measured in the size range 10–500?nm during spontaneous breathing. Results The deposited dose rate increased with increasing severity of the disease. However, the deposition probability of the ultrafine combustion particles (< 100?nm) was decreased in COPD patients. The deposition probability was associated with both breathing parameters and lung function, but could be predicted only based on lung function. Conclusions The higher deposited dose rate of inhaled air pollution particles in COPD patients may be one of the factors contributing to their increased vulnerability. The strong correlations between lung function and particle deposition, especially in the size range of 20–30?nm, suggest that altered particle deposition could be used as an indicator respiratory disease.

2012-01-01

225

Environment as a Critical Factor for the Pathogenesis and Outcome of Gastrointestinal Disease: Experimental and Human Inflammatory Bowel Disease and Helicobacter-Induced Gastritis  

Microsoft Academic Search

Environmental factors play an important role in the manifestation, course, and prognosis of diseases of the gastrointestinal tract such as inflammatory bowel disease (IBD) and Helicobacter pylori-induced gastritis. These two disease complexes were chosen for a discussion of the contribution of environmental factors to the disease outcome in humans and animal models. Dissecting complex diseases like IBD and Helicobacter-induced gastritis

A. Bleich; M. Mähler

2005-01-01

226

Hydrodynamic interactions in metal rod-like particle suspensions due to induced charge electroosmosis  

SciTech Connect

We present a theoretical and experimental study of the role of hydrodynamic interactions on the motion and dispersion of metal rod-like particles in the presence of an externally applied electric field. In these systems, the electric field polarizes the particles and induces an electroosmosis flow relative to the surface of each particle. The simulations include the effect of the gravitational body force, buoyancy, far-field hydrodynamic interactions, near-field lubrication forces, and electric field interactions. The particles in the simulations and experiments were observed to experience repeated pairing interactions in which they come together axially with their ends approaching each other, slide past one another until their centers approach, and then push apart. These interactions were confirmed in measurements of particle orientations and velocities, pair distribution functions, and net dispersion of the suspension. For large electric fields, the pair distribution functions show accumulation and depletion regions consistent with many pairing events. For particle concentrations of 1e8 particles/mL and higher, dispersion within the suspension dramatically increases with increased field strength.

Rose, K A; Hoffman, B; Saintillan, D; Shaqfeh, E G; Santiago, J G

2008-05-05

227

Hamiltonian stochastic processes induced by successive wave-particle interactions in stimulated Raman scattering.  

PubMed

The long-time dynamics of particles interacting resonantly with large-amplitude coherent plasma wave is investigated in the kinetic regime of stimulated Raman scattering in which particle trapping plays a major role (and which corresponds to a high value of the parameter k_{EPW}lambda_{D}, where k_{EPW} is the plasma wave vector and lambda_{D} is the electron Debye length). Using Vlasov simulations, the dynamics of such particles become stochastic when repeated wave-particle interactions take place. For small values of the ratio tau_{auto}/tau_{b} of the autocorrelation time to the bounce time of particle (condition usually met in backward propagation of the scattered wave) the turbulent regime results in the merging of phase-space trapping vortices according to a weak turbulencelike scenario. For high values of tau_{auto}/tau_{b} (or narrow spectrum of longitudinal electric field as met when only one plasma wave is present), the stochasticity is now induced by particle trapping, detrapping, and retrapping in the adiabatically fluctuating field. The stochastic transitions performed by resonant particles above (or below) the separatrix limit in phase space determine now the long-time plasma evolution. PMID:19518356

Ghizzo, A; Del Sarto, D; Reveille, T

2009-04-01

228

Redefining Parkinson's Disease Research Using Induced Pluripotent Stem Cells  

PubMed Central

Parkinson’s disease (PD) is a movement disorder associated with the degeneration of nigral dopaminergic (DA) neurons. One of the greatest obstacles for PD research is the lack of patient-specific nigral DA neurons for mechanistic studies and drug discovery. The advent of induced pluripotent stem cells (iPSCs) has overcome this seemingly intractable problem and changed PD research in many profound ways. In this review, we discuss recent development in the generation and analyses of patient-specific iPSC-derived midbrain DA neurons. Results from this novel platform of human cellular models of PD have offered a tantalizing glimpse of the promising future of PD research. With the development of the latest genomic modification technologies, dopaminergic neuron differentiation methodologies, and cell transplantation studies, PD research is poised to enter a new phase that utilizes the human model system to identify the unique vulnerabilities of human nigral DA neurons and disease-modifying therapies based on such mechanistic studies.

Pu, Jiali; Jiang, Houbo; Zhang, Baorong; Feng, Jian

2012-01-01

229

Structural brain plasticity in Parkinson's disease induced by balance training.  

PubMed

We investigated morphometric brain changes in patients with Parkinson's disease (PD) that are associated with balance training. A total of 20 patients and 16 healthy matched controls learned a balance task over a period of 6 weeks. Balance testing and structural magnetic resonance imaging were performed before and after 2, 4, and 6 training weeks. Balance performance was re-evaluated after ?20 months. Balance training resulted in performance improvements in both groups. Voxel-based morphometry revealed learning-dependent gray matter changes in the left hippocampus in healthy controls. In PD patients, performance improvements were correlated with gray matter changes in the right anterior precuneus, left inferior parietal cortex, left ventral premotor cortex, bilateral anterior cingulate cortex, and left middle temporal gyrus. Furthermore, a TIME × GROUP interaction analysis revealed time-dependent gray matter changes in the right cerebellum. Our results highlight training-induced balance improvements in PD patients that may be associated with specific patterns of structural brain plasticity. In summary, we provide novel evidence for the capacity of the human brain to undergo learning-related structural plasticity even in a pathophysiological disease state such as in PD. PMID:23916062

Sehm, Bernhard; Taubert, Marco; Conde, Virginia; Weise, David; Classen, Joseph; Dukart, Juergen; Draganski, Bogdan; Villringer, Arno; Ragert, Patrick

2014-01-01

230

The Endotoxin-Induced Neuroinflammation Model of Parkinson's Disease  

PubMed Central

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra. Although the exact cause of the dopaminergic neurodegeneration remains elusive, recent postmortem and experimental studies have revealed an essential role for neuroinflammation that is initiated and driven by activated microglial and infiltrated peripheral immune cells and their neurotoxic products (such as proinflammatory cytokines, reactive oxygen species, and nitric oxide) in the pathogenesis of PD. A bacterial endotoxin-based experimental model of PD has been established, representing a purely inflammation-driven animal model for the induction of nigrostriatal dopaminergic neurodegeneration. This model, by itself or together with genetic and toxin-based animal models, provides an important tool to delineate the precise mechanisms of neuroinflammation-mediated dopaminergic neuron loss. Here, we review the characteristics of this model and the contribution of neuroinflammatory processes, induced by the in vivo administration of bacterial endotoxin, to neurodegeneration. Furthermore, we summarize the recent experimental therapeutic strategies targeting endotoxin-induced neuroinflammation to elicit neuroprotection in the nigrostriatal dopaminergic system. The potential of the endotoxin-based PD model in the development of an early-stage specific diagnostic biomarker is also emphasized.

Tufekci, Kemal Ugur; Genc, Sermin; Genc, Kursad

2011-01-01

231

Castration Induces Parkinson Disease Pathologies in Young Male Mice via Inducible Nitric-oxide Synthase*  

PubMed Central

Although Parkinson disease (PD) is a progressive neurodegenerative disorder, available animal models do not exhibit irreversible neurodegeneration, and this is a major obstacle in finding out an effective drug against this disease. Here we delineate a new irreversible model to study PD pathogenesis. The model is based on simple castration of young male mice. Levels of inducible nitric-oxide synthase (iNOS), glial markers (glial fibrillary acidic protein and CD11b), and ?-synuclein were higher in nigra of castrated male mice than normal male mice. On the other hand, after castration, the level of glial-derived neurotrophic factor (GDNF) markedly decreased in the nigra of male mice. Accordingly, castration also induced the loss of tyrosine hydroxylase-positive neurons in the nigra and decrease in tyrosine hydroxylase-positive fibers and neurotransmitters in the striatum. Reversal of nigrostriatal pathologies in castrated male mice by subcutaneous implantation of 5?-dihydrotestosterone pellets validates an important role of male sex hormone in castration-induced nigrostriatal pathology. Interestingly, castration was unable to cause glial activation, decrease nigral GDNF, augment the death of nigral dopaminergic neurons, induce the loss of striatal fibers, and impair neurotransmitters in iNOS?/? male mice. Furthermore, we demonstrate that iNOS-derived NO is responsible for decreased expression of GDNF in activated astrocytes. Together, our results suggest that castration induces nigrostriatal pathologies via iNOS-mediated decrease in GDNF. These results are important because castrated young male mice may be used as a simple, toxin-free, and nontransgenic animal model to study PD-related nigrostriatal pathologies, paving the way for easy drug screening against PD.

Khasnavis, Saurabh; Ghosh, Anamitra; Roy, Avik; Pahan, Kalipada

2013-01-01

232

Lateral aggregation induced by magnetic perturbations in a magnetorheological fluid based on non-Brownian particles.  

PubMed

A study of lateral aggregation, induced by an oscillatory field, in a magnetorheological fluid based on non-Brownian magnetic particles is presented. We investigate the behavior of chains formed by the particles, due to the simultaneous application of a static magnetic field and a sinusoidal magnetic field transverse to each other. We show that the effective oscillating field enhances the aggregation process. We discuss this result in terms of an effective particle concentration induced by the oscillating field when chains oscillate angularly and sweep the area around them. The oscillating field produces a lateral aggregation similar to that observed in systems composed of Brownian particles which is induced by thermal fluctuations. We study the effect of the oscillating field on the angular amplitude described by single chains. It is observed that the angular amplitude decreases as the frequency of the oscillating field increases; we discuss this behavior numerically in terms of a simple model for this system. Lateral aggregation is studied in detail in isolated pairs of chains of equal length at several conditions of separation and displacement. From the results, a phase diagram is obtained showing the conditions under which aggregation is possible. PMID:24125266

Moctezuma, R E; Donado, F; Arauz-Lara, J L

2013-09-01

233

Lateral aggregation induced by magnetic perturbations in a magnetorheological fluid based on non-Brownian particles  

NASA Astrophysics Data System (ADS)

A study of lateral aggregation, induced by an oscillatory field, in a magnetorheological fluid based on non-Brownian magnetic particles is presented. We investigate the behavior of chains formed by the particles, due to the simultaneous application of a static magnetic field and a sinusoidal magnetic field transverse to each other. We show that the effective oscillating field enhances the aggregation process. We discuss this result in terms of an effective particle concentration induced by the oscillating field when chains oscillate angularly and sweep the area around them. The oscillating field produces a lateral aggregation similar to that observed in systems composed of Brownian particles which is induced by thermal fluctuations. We study the effect of the oscillating field on the angular amplitude described by single chains. It is observed that the angular amplitude decreases as the frequency of the oscillating field increases; we discuss this behavior numerically in terms of a simple model for this system. Lateral aggregation is studied in detail in isolated pairs of chains of equal length at several conditions of separation and displacement. From the results, a phase diagram is obtained showing the conditions under which aggregation is possible.

Moctezuma, R. E.; Donado, F.; Arauz-Lara, J. L.

2013-09-01

234

A sandwiched flexible polymer mold for control of particle-induced defects in nanoimprint lithography  

NASA Astrophysics Data System (ADS)

Particle related defects are one of the key concerns for nanoimprint lithography, since the particle can amplify the defect to become much larger than the particle itself. We developed a flexible tri-layer mold for control of particle-induced defects. The mold was composed of a PDMS cushion layer sandwiched between a rigid imprint pattern layer and a plastic polyethylene terephthalate (PET) backplane. The PET foil was used as the backplane of the mold to protect the sticky PDMS surface. The PDMS as a cushion layer could locally deform to conform the shape of substrate due to its high elasticity. The multifunctional epoxysiloxane was used for the formation of an imprint layer because of its insensitivity toward oxygen during curing, high transparency, excellent mechanical strength and high resistance to oxygen plasma after cross-linking. Nanostructures with different geometries and sizes were faithfully duplicated by this mold through a UV-curing imprint process. The particle-induced defectivity was dramatically improved by the deformation of the PDMS cushion layer with a slight external pressure. 500 nm pitch grating structures were successfully imprinted on a microposts array surface, both the top and the intervening bottom portions between the microposts.

Li, Bin; Zhang, Jizong; Ge, Haixiong

2013-01-01

235

Flow-induced aggregation and breakup of particle clusters controlled by surface nanoroughness.  

PubMed

Interactions between colloidal particles are strongly affected by the particle surface chemistry and composition of the liquid phase. Further complexity is introduced when particles are exposed to shear flow, often leading to broad variation of the final properties of formed clusters. Here we discover a new dynamical effect arising in shear-induced aggregation where repeated aggregation and breakup events cause the particle surface roughness to irreversibly increase with time, thus decreasing the bond adhesive energy and the resistance of the aggregates to breakup. This leads to a pronounced overshoot in the time evolution of the aggregate size, which can only be explained with the proposed mechanism. This is demonstrated by good agreement between time evolution of measured light-scattering data and those calculated with a population-balance model taking into account the increase in the primary particle nanoroughness caused by repeated breakup events resulting in the decrease of bond adhesive energy as a function of time. Thus, the proposed model is able to reproduce the overshoot phenomenon by taking into account the physicochemical parameters, such as pH, till now not considered in the literature. Overall, this new effect could be exploited in the future to achieve better control over the flow-induced assembly of nanoparticles. PMID:24156516

Moussa, Amgad S; Lattuada, Marco; Conchúir, Breanndán Ó; Zaccone, Alessio; Morbidelli, Massimo; Soos, Miroslav

2013-11-26

236

Indirect control of transport and interaction-induced negative mobility in an overdamped system of two coupled particles  

NASA Astrophysics Data System (ADS)

One-dimensional transport of an overdamped Brownian particle biased by an external constant force does not exhibit negative mobility. However, when the particle is coupled to another particle, negative mobility can arise. We present a minimal model and propose a scenario in which only one (say, the first) particle is dc biased by a constant force and ac driven by an unbiased harmonic signal. In this way we intend to achieve two aims at once: (i) negative mobility of the first particle, which is exclusively induced by coupling to the second particle and (ii) indirect control of the transport properties of the second particle by manipulating the first particle only. For instance, the sign and amplitude of the averaged stationary velocity of the second particle can be steered by the driving applied to the first particle. As an experimentally realizable system, we propose two coupled resistively shunted Josephson junctions.

Januszewski, M.; ?uczka, J.

2011-05-01

237

Individual differences in regional deposition of 6-micron particles in humans with induced bronchoconstriction  

SciTech Connect

The effect of induced bronchoconstriction on regional lung deposition of 6 microns aerodynamic diameter 99mTc-labeled Teflon particles was studied in eight healthy non-smokers. The Teflon particles were inhaled at 0.5 l/s from a 25-l glass bulb with 8-12 maximally deep breaths on four consecutive days. For three exposures, various degrees of bronchoconstriction were induced using an aerosol of methacholine bromide before the inhalation of the Teflon particles. For the fourth (control) exposure, bronchoconstriction was induced after the inhalation of the Teflon particles. The degree of bronchoconstriction was quantified by measurements of airway resistance (Raw) using a whole-body plethysmograph. The fraction of alveolarly deposited particles in the lung (FAD) was estimated by measurements of radioactivity in the lung immediately after inhalation of the Teflon particles and 6 h later. Earlier studies have shown that when the mucociliary transport is stimulated with the cholinergic aerosol used in this study, the 6-h retention values (Ret6) are similar to the 24-h values. Within the subjects there was a close relationship between Raw and Ret6 with a decrease of Ret6 with increased Raw. This decrease varied markedly among the subjects. The relationship between Raw and Ret6 calculated from the model by the Task Group on Lung Dynamics, in which the airway diameters were varied, agreed with our experimental data. On an average, airway resistance of 1 and 2 cm H2O.s/l correspond to FAD of about 50% and 25%, respectively.

Svartengren, M.; Philipson, K.; Camner, P.

1989-01-01

238

Quantitative elemental detection of size-segregated particles using laser-induced breakdown spectroscopy  

NASA Astrophysics Data System (ADS)

In order to simulate coal combustion and develop optimal and stable boiler control systems in real power plants, it is imperative to obtain the detailed information in coal combustion processes as well as to measure species contents in fly ash, which should be controlled and analyzed for enhancing boiler efficiency and reducing environmental pollution. The fly ash consists of oxides (SiO2, Al2O3, Fe2O3, CaO, and so on), unburned carbon, and other minor elements. Recently laser-induced breakdown spectroscopy (LIBS) technique has been applied to coal combustion and other industrial fields because of the fast response, high sensitivity, real-time and non-contact features. In these applications it is important to measure controlling factors without any sample preparation to maintain the real-time measurement feature. The relation between particle content and particle diameter is also one of the vital researches, because compositions of particles are dependent on their diameter. In this study, we have detected the contents of size-segregated particles using LIBS. Particles were classified by an Anderson cascade impactor and their contents were measured using the output of 1064 nm YAG laser, a spectrograph and an ICCD camera. The plasma conditions such as plasma temperature are dependent on the size of particles and these effects must be corrected to obtain quantitative information. The plasma temperature was corrected by the emission intensity ratio from the same atom. Using this correction method, the contents of particles can be measured quantitatively in fixed experimental parameters. This method was applied to coal and fly ash from a coal-fired burner to measure unburned carbon and other contents according to the particle diameter. The acquired results demonstrate that the LIBS technique is applicable to measure size-segregated particle contents in real time and this method is useful for the analysis of coal combustion and its control because of its sensitive and fast analysis features.

Wang, Zhen Zhen; Deguchi, Yoshihiro; Kuwahara, Masakazu; Taira, Takuya; Zhang, Xiao Bo; Yan, Jun Jie; Liu, Ji Ping; Watanabe, Hiroaki; Kurose, Ryoichi

2013-09-01

239

Optimizing particle size for targeting diseased microvasculature: from experiments to artificial neural networks  

PubMed Central

Background Nanoparticles with different sizes, shapes, and surface properties are being developed for the early diagnosis, imaging, and treatment of a range of diseases. Identifying the optimal configuration that maximizes nanoparticle accumulation at the diseased site is of vital importance. In this work, using a parallel plate flow chamber apparatus, it is demonstrated that an optimal particle diameter (dopt) exists for which the number (ns) of nanoparticles adhering to the vessel walls is maximized. Such a diameter depends on the wall shear rate (S). Artificial neural networks are proposed as a tool to predict ns as a function of S and particle diameter (d), from which to eventually derive dopt. Artificial neural networks are trained using data from flow chamber experiments. Two networks are used, ie, ANN231 and ANN2321, exhibiting an accurate prediction for ns and its complex functional dependence on d and S. This demonstrates that artificial neural networks can be used effectively to minimize the number of experiments needed without compromising the accuracy of the study. A similar procedure could potentially be used equally effectively for in vivo analysis.

Boso, Daniela P; Lee, Sei-Young; Ferrari, Mauro; Schrefler, Bernhard A; Decuzzi, Paolo

2011-01-01

240

Applications of recent measurements of low energy charged particles induced nuclear reactions on light nuclei  

SciTech Connect

This report discusses the applications of deuteron and triton induced nuclear reactions to the general problem of the diagnostics of charged and neutral particle beams and of high temperature deuterium and tritium plasmas. The motivation for these applications lies primarily in the crucial role which such beams and plasmas occupy in the contemporary CTR development effort. Explains that the physical basis of these applications is the sensitive dependence of these cross sections upon the center mass energy of the reactants (in the case of the low energy particle beam) or to the temperature (in the case of a plasma).

Cecil, F.E.

1983-04-01

241

Particle Motion under Shear-Induced Migration in Square-PDMS Microchannels  

NASA Astrophysics Data System (ADS)

An experimental study has been conducted to quantitatively characterize particle motion under shear-induced migration in square-PDMS microchannels by applying ?-PTV technique. It is shown that particles are accumulated at the equilibrium position of 0.67H, with H being a half width of the channel, which is analogous to what is observed in circular tube flow in macro scale. Since high shear rate can be induced due to the scale effect, particle migration occurs markedly even at low Reynolds number ranging from 4 to 57 while this phenomenon dose not typically occur at this range of the Reynolds number in macro scale. At Re = 57, it is found that particles are nearly absent around the center of the channel, which is coincident with previous numerical result obtained for a square duct at Re = 100. The outermost edge of particle cluster is in good agreement with previous study. It is rapidly converging to about y/H = 0.7 at L3 = 1, where L3 = (0.5dp/H)^3(l/2H)Re is the reduced tube length, dp is the diameter of the spherical particle and l is the measurement position from channel inlet. Since the thickness of particle-free layer is largest at L3 = 1, it is indicated that plasma selectivity and total amount of plasma separated can be maximized at this value of L3 when serum from the whole blood is separated into side channels in lab-on-a-chip systems, by minimizing the clogging of RBCs (Red Blood Cells). The present study is expected to give optimum factors for designing of microfluidic systems.

Kim, Young Won; Yoo, Jung Yul

2006-11-01

242

Induced pluripotent stem cell technology for disease modeling and drug screening with emphasis on lysosomal storage diseases  

PubMed Central

The recent derivation of disease-specific induced pluripotent stem cells (iPSCs) from somatic cells of patients with familial and sporadic forms of diseases and the demonstration of their ability to give rise to disease-relevant cell types provide an excellent opportunity to gain further insights into the mechanisms responsible for the pathophysiology of these diseases and develop novel therapeutic drugs. Here, we review the recent advances in iPSC technology for modeling of various lysosomal storage diseases (LSDs) and discuss possible strategies through which LSD-iPSCs can be exploited to identify novel drugs and improve future clinical treatment of LSDs.

2012-01-01

243

Fiber Bragg grating filter using evaporated induced self assembly of silica nano particles  

NASA Astrophysics Data System (ADS)

In the present work we conduct a study of fiber filters produced by evaporation of silica particles upon a MM-fiber core. A band filter was designed and theoretically verified using a 2D Comsol simulation model of a 3D problem, and calculated in the frequency domain in respect to refractive index. The fiber filters were fabricated by stripping and chemically etching the middle part of an MM-fiber until the core was exposed. A mono layer of silica nano particles were evaporated on the core using an Evaporation Induced Self-Assembly (EISA) method. The experimental results indicated a broader bandwidth than indicated by the simulations which can be explained by the mismatch in the particle size distributions, uneven particle packing and finally by effects from multiple mode angles. Thus, there are several closely connected Bragg wavelengths that build up the broader bandwidth. The experimental part shows that it is possible by narrowing the particle size distributing and better control of the particle packing, the filter effectiveness can be greatly improved.

Hammarling, Krister; Zhang, Renyung; Manuilskiy, Anatoliy; Nilsson, Hans-Erik

2014-03-01

244

440 Gluten Induced Systemic Disease (GISD) with Distinct Clinical Phenotype Different from Celiac Disease  

PubMed Central

Background Patients who have complex presentation involving multiple organs are difficult to diagnose. Non-infectious diseases that present with similar clinical patterns yet test negative to the known markers often arise due to certain change in environment or exposure. Such syndromes and diseases require careful study and call for new diagnostic modalities. Methods Patients who have complex presentation involving multiple organs are difficult to diagnose. Non-infectious diseases that present with similar clinical patterns yet test negative to the known markers often arise due to certain change in environment or exposure. Such syndromes and diseases require careful study and call for new diagnostic modalities. Results Average length of symptoms prior to diagnosis was 5 years. Of 42 patients 34 were previously treated for 3 or more health issues. None of the patients were previously diagnosed with celiac disease, 7 patients underwent diagnostic endoscopy with biopsies. Most prevalent symptom (94%) was severe fatigue. Following symptoms were reported on questionnaire: sleep problems requiring medications, concentration/memory problem, constipation, depression, headaches/migraine, gastroesophageal reflux, nocturnal muscle spasms, abdominal distension, joint pain, rashes, and gum recession. Most common laboratory abnormality was positive ANA with homogenous pattern. All but 2 patients tested negative to tTG, gliadin and endomyseal antibodies. Of 17 patients screened for food allergy 94% were positive for 10+4 foods by skin test. Hundred percent of patients reported significant improvement at 1 month interval with complete resolution of above listed clinical symptoms at 6 months. Best recovery was achieved in patients when treatment regimen included supplemental therapy with CoQ10, fish oil and digestive enzymes based on papain. Of 25 patients attempted gluten introduction after complete clinical recovery 100% reported relapse of symptoms within 48 hours following gluten challenge. Conclusions We report the emergence of new clinical phenotype of non-celiac gluten induced systemic disease (GISD). Although recent publications specifying existence and possible explanation of this condition arise, mechanism is not understood. Thus further studies are needed to facilitate recognition, testing and understanding of GISD.

Kushnir, Nataliya M.

2012-01-01

245

A Lagrangian particle model to predict the airborne spread of foot-and-mouth disease virus  

NASA Astrophysics Data System (ADS)

Airborne spread of bioaerosols in the boundary layer over a complex terrain is simulated using a Lagrangian particle model, and applied to modelling the airborne spread of foot-and-mouth disease (FMD) virus. Two case studies are made with study domains located in a hilly region in the northwest of the Styrian capital Graz, the second largest town in Austria. Mountainous terrain as well as inhomogeneous and time varying meteorological conditions prevent from application of so far used Gaussian dispersion models, while the proposed model can handle these realistically. In the model, trajectories of several thousands of particles are computed and the distribution of virus concentration near the ground is calculated. This allows to assess risk of infection areas with respect to animal species of interest, such as cattle, swine or sheep. Meteorological input data like wind field and other variables necessary to compute turbulence were taken from the new pre-operational version of the non-hydrostatic numerical weather prediction model LMK ( Lokal-Modell-Kürzestfrist) running at the German weather service DWD ( Deutscher Wetterdienst). The LMK model provides meteorological parameters with a spatial resolution of about 2.8 km. To account for the spatial resolution of 400 m used by the Lagrangian particle model, the initial wind field is interpolated upon the finer grid by a mass consistent interpolation method. Case studies depict a significant influence of local wind systems on the spread of virus. Higher virus concentrations at the upwind side of the hills and marginal concentrations in the lee are well observable, as well as canalization effects by valleys. The study demonstrates that the Lagrangian particle model is an appropriate tool for risk assessment of airborne spread of virus by taking into account the realistic orographic and meteorological conditions.

Mayer, D.; Reiczigel, J.; Rubel, F.

246

Fine oil combustion particle bioavailable constituents induce molecular profiles of oxidative stress, altered function, and cellular injury in cardiomyocytes.  

PubMed

Epidemiological studies have shown a positive association between exposure to air particulate matter (PM) pollution and adverse cardiovascular health effects in susceptible subpopulations such as those with pre-existing cardiovascular disease. The mechanism(s) through which pulmonary deposited PM, particularly fine PM2.5, PM with mass median aerodynamic diameter <2.5 microm, affects the cardiovascular system is currently not known and remains a major focus of investigation. In the present study, the transcriptosome and transcription factor proteome were examined in rat neonatal cardiomyocyte (RCM) cultures, following an acute exposure to bioavailable constituents of PM2.5 oil combustion particles designated residual oil fly ash leachate (ROFA-L). Out of 3924 genes examined, 38 genes were suppressed and 44 genes were induced following a 1-h exposure to 3.5 microg/ml of a particle-free leachate of ROFA (ROFA-L). Genomic alterations in pathways related to IGF-1, VEGF, IL-2, PI3/AKT, cardiovascular disease, and free radical scavenging, among others, were detected 1 h postexposure to ROFA-L. Global gene expression was altered in a manner consistent with cardiac myocyte electrophysiological remodeling, cellular oxidative stress, and apoptosis. ROFA-L altered the transcription factor proteome by suppressing activity of 24 and activating 40 transcription factors out of a total of 149. Genomic alterations were found to correlate with changes in transcription factor proteome. These acute changes indicate pathological molecular alterations, which may lead to possible chronic alterations to the cardiac myocyte. These data also potentially relate underlying cardiovascular effects from occupational exposure to ROFA and identify how particles from specific emission sources may mediate ambient PM cardiac effects. PMID:17934955

Knuckles, Travis L; Dreher, Kevin L

2007-11-01

247

Effect of oxide particle distribution on the helium-induced fracture of copper  

SciTech Connect

Long-term exposure to tritium (H[sup 3]) gas can degrade the mechanical properties of copper alloys while similar exposure to protium (H[sup 1]) gas does not cause such degradation. This difference in behavior is attributed to the presence of helium which is generated by the radioactive decay of tritium. The accumulation of helium, which is virtually insoluble in the copper lattice, can cause the nucleation of cavities along grain boundaries and promote intergranular fracture. Permeation studies have shown that oxide particles act as trap sites for diffusing hydrogen isotopes, and thus may affect the susceptibility of copper to helium-induced degradation by altering the initial tritium distribution in the metal lattice. Tensile and metallographic data demonstrate that oxide particles trap both tritium and helium and decrease the susceptibility of copper to helium-induced intergranular fracture. 25 refs, 3 tabs, 12 figs.

Wheeler, D.A.

1990-01-01

248

Experimental Study of Laser-Induced Breakdown Spectroscopy (LIBS) for Direct Analysis of Coal Particle Flow.  

PubMed

Laser-induced breakdown spectroscopy (LIBS) was employed to directly analyze coal particles in the form of descending flow. Coal-particle ablation was performed using a 1064 nm neodymium-doped yttrium aluminum garnet (Nd : YAG) laser at atmospheric conditions. Spectral identification schemes were used to acquire spectra containing all the emission lines of the important elements in coal. These acquired spectra were classified as representative spectra. The background of the line emission plus three times the standard deviation of the background of the representative spectra was chosen as the threshold value. A method using a single line and a method using combined multiple lines (C, 247.8 nm; N, 746.8 nm; Si, 288.2 nm; and Ca, 396.8 nm) were compared to obtain the best results for the spectral identification of coal particle flow. The feasibility of rejecting the partial breakdown spectra was verified using quantitative analysis of fixed carbon in coal. PMID:25014723

Zheng, Jianping; Lu, Jidong; Zhang, Bo; Dong, Meirong; Yao, Shunchun; Lu, Weiye; Dong, Xuan

2014-06-01

249

Sendai virus induced cytoplasmic actin remodeling correlates with efficient virus particle production.  

PubMed

Cytoplasmic actins have been found interacting with viral proteins and identified in virus particles. We analyzed by confocal microscopy the cytoplasmic ?- and ?-actin patterns during the course of Sendai virus infections in polarized cells. We observed a spectacular remodeling of the ?-cytoplasmic actin which correlated with productive viral multiplication. Conversely, suppression of M during the course of a productive infection resulted in the decrease of particle production and the absence of ?-actin remodeling. As concomitant suppression of ?- and ?-actins resulted as well in reduction of virus particle production, we propose that Sendai virus specifically induces actin remodeling in order to promote efficient virion production. Beta- and ?-cytoplasmic actin recruitment could substitute for that of the endosomal sorting complex required for transport (ESCRT) mobilized by other enveloped viruses but apparently not used by Sendai virus. PMID:21075412

Miazza, Vincent; Mottet-Osman, Geneviève; Startchick, Sergei; Chaponnier, Christine; Roux, Laurent

2011-02-01

250

Convective and Diffusive Energetic Particle Losses Induced by Shear Alfven Waves in the ASDEX Upgrade Tokamak  

SciTech Connect

We present here the first phase-space characterization of convective and diffusive energetic particle losses induced by shear Alfven waves in a magnetically confined fusion plasma. While single toroidal Alfven eigenmodes (TAE) and Alfven cascades (AC) eject resonant fast ions in a convective process, an overlapping of AC and TAE spatial structures leads to a large fast-ion diffusion and loss. Diffusive fast-ion losses have been observed with a single TAE above a certain threshold in the fluctuation amplitude.

Garcia-Munoz, M.; Hicks, N.; Bilato, R.; Bobkov, V.; Bruedgam, M.; Fahrbach, H.-U.; Igochine, V.; Maraschek, M.; Sassenberg, K. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association Boltzmannstrasse 2, D-85748 Garching (Germany); Voornveld, R. van [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Classen, I. G. J. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association Boltzmannstrasse 2, D-85748 Garching (Germany); FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Jaemsae, S. [Helsinki University of Technology, Association Euratom-Tekes, P.O. Box 4100, FIN-02015 HUT (Finland)

2010-05-07

251

Shear-induced melting and reentrant positional ordering in a system of spherical particles  

Microsoft Academic Search

Computer simulations of dense systems of soft spheres subjected to a shear flow show not only the phenomena of shear-induced melting—transition from a crytalline to an amorphous state—but, at high shear rates, a second nonequilibrium phase transition to a new positionally ordered state. The particles form strings parallel to the stream lines; the strings, in turn, are arranged in a

S. Hess

1985-01-01

252

Calculation of radiation-induced DNA damage from photons and tritium beta-particles  

Microsoft Academic Search

Radiation-induced damage in nucleosomal DNA was modelled by Monte Carlo means. An atomistic representation of DNA with a first\\u000a hydration shell was used. DNA single- and double-strand break (SSB and DSB) yields were calculated for 137Cs photons, x-rays and tritium beta-particles. Monte Carlo-generated electron tracks for liquid water were used to model energy\\u000a deposition. Chemical evolution of a track and

V. V. Moiseenko; R. N. Hamm; A. J. Waker; W. V. Prestwich

2001-01-01

253

Studies on fission phenomena induced by charged particles using the JAERI tandem accelerator  

Microsoft Academic Search

Charged-particle-induced fission has been studied using the JAERI tandem accelerator. Characteristics of the symmetric mass division process at high angular momentum are investigated in the region of relatively light mass systems: 37Cl + 68Zn and 16O + 89Y. Observed widths of the mass and total kinetic energy distributions are broader than those expected from the liquid drop model. Pre-scission 4He

Y. Nagame; H. Ikezoe; N. Shikazono; T. Ohtsuki; H. Nakahara

1991-01-01

254

Ebola Virus VP40Induced Particle Formation and Association with the Lipid Bilayer  

Microsoft Academic Search

Viral protein 40 (VP40) of Ebola virus appears equivalent to matrix proteins of other viruses, yet little is known about its role in the viral life cycle. To elucidate the functions of VP40, we investigated its ability to induce the formation of membrane-bound particles when it was expressed apart from other viral proteins. We found that VP40 is indeed able

LUKE D. JASENOSKY; GABRIELE NEUMANN; IGOR LUKASHEVICH; YOSHIHIRO KAWAOKA

2001-01-01

255

Polyethylene wear particles induce TLR 2 upregulation in the synovial layer of mice.  

PubMed

A cellular and receptor mediated response to ultra-high-molecular-weight-polyethylene (UHMWPE) wear particles results in a release of proinflammatory cytokines and induces an inflammatory reaction causing osteolysis in total joint replacement. This investigation offers insight into the toll-like receptor (TLR) mediated activation by polyethylene wear particles in the synovial layer of mice. We hypothesized that, similar to recent in vitro results, UHMWPE particles lead to an upregulation of TLR 1 and 2 and TLR 4 in vivo in the synovial tissue of mice as well. Therefore, UHMWPE particles were generated in a common knee simulator according to the ISO standard, separated by acid digestion and determined by scanning electron microscopy. Endotoxin was removed using a method based on ultracentrifugation. A particle suspension (50 ?l; 0.1 vol./vol.%) was injected into the left knee joint of female Balb/c mice (n = 8). In a control group, phosphate-buffered saline was injected into the left knee of Balb/c mice (n = 8). The mice were sacrificed after 7 days. Immunohistochemical staining was performed with TLR 1, 2 and 4 polyclonal antibodies for Balb/c mice and evaluated by light microscopy. The particle-stimulated group showed a thickened synovial layer, an increased cellular infiltration and a TLR 2-upregulation in the synovial layer compared to the control group. An increased expression of TLR 1 and TLR 4 could not be demonstrated. These results indicate a mainly TLR 2-induced inflammation to polyethylene wear debris in the synovial layer of mice. PMID:24249629

Paulus, A C; Frenzel, J; Ficklscherer, A; Roßbach, B P; Melcher, C; Jansson, V; Utzschneider, S

2014-02-01

256

Laser-induced thermophoresis of individual particles in a viscous liquid.  

PubMed

This paper presents a detailed investigation of the motion of individual micro-particles in a moderately-viscous liquid in direct response to a local, laser-induced temperature gradient. By measuring particle trajectories in 3D, and comparing them to a simulated temperature profile, it is confirmed that the thermally-induced particle motion is the direct result of thermophoresis. The elevated viscosity of the liquid provides for substantial differences in the behavior predicted by various models of thermophoresis, which in turn allows measured data to be most appropriately matched to a model proposed by Brenner. This model is then used to predict the effective force resulting from thermophoresis in an optical trap. Based on these results, we predict when thermophoresis will strongly inhibit the ability of radiation pressure to trap nano-scale particles. The model also predicts that the thermophoretic force scales linearly with the viscosity of the liquid, such that choice of liquid plays a key role in the relative strength of the thermophoretic and radiation forces. PMID:21643311

Schermer, Ross T; Olson, Colin C; Coleman, J Patrick; Bucholtz, Frank

2011-05-23

257

Particles from wood smoke and traffic induce differential pro-inflammatory response patterns in co-cultures  

SciTech Connect

The inflammatory potential of particles from wood smoke and traffic has not been well elucidated. In this study, a contact co-culture of monocytes and pneumocytes was exposed to 10-40 {mu}g/cm{sup 2} of particles from wood smoke and traffic for 12, 40 and 64 h to determine their influence on pro-inflammatory cytokine release (TNF-{alpha}, IL-1, IL-6, IL-8) and viability. To investigate the role of organic constituents in cytokine release the response to particles, their organic extracts and the washed particles were compared. Antagonists were used to investigate source-dependent differences in intercellular signalling (TNF-{alpha}, IL-1). The cytotoxicity was low after exposure to particles from both sources. However, wood smoke, and to a lesser degree traffic-derived particles, induced a reduction in cell number, which was associated with the organic fraction. The release of pro-inflammatory cytokines was similar for both sources after 12 h, but traffic induced a greater release than wood smoke particles with increasing exposure time. The organic fraction accounted for the majority of the cytokine release induced by wood smoke, whereas the washed traffic particles induced a stronger response than the corresponding organic extract. TNF-{alpha} and IL-1 antagonists reduced the release of IL-8 induced by particles from both sources. In contrast, the IL-6 release was only reduced by the IL-1 antagonist during exposure to traffic-derived particles. In summary, particles from wood smoke and traffic induced differential pro-inflammatory response patterns with respect to cytokine release and cell number. Moreover, the influence of the organic particle fraction and intercellular signalling on the pro-inflammatory response seemed to be source-dependent.

Kocbach, Anette [Division of Environmental Medicine, Norwegian Institute of Public Health, Geitemyrsveien 75, 0462 Oslo (Norway)], E-mail: anette.kocbach@fhi.no; Herseth, Jan Inge [Biomedical Laboratory Science, Faculty of Health Sciences, Oslo University College, Pilestredet 50, 0167 Oslo (Norway); Lag, Marit; Refsnes, Magne; Schwarze, Per E. [Division of Environmental Medicine, Norwegian Institute of Public Health, Geitemyrsveien 75, 0462 Oslo (Norway)

2008-10-15

258

Early corticosteroid administration in experimental radiation-induced heart disease  

SciTech Connect

The ability of dexamethasone (DEX) to reduce the severity of the late stage of radiation-induced heart disease (RIHD) was assessed in 25 New Zealand white rabbits. Ten rabbits served as unirradiated controls (CONT). In Group A, seven rabbits received intravenous DEX prior to irradiation and every 24 hours for three consecutive days. DEX was not administered to the eight rabbits in Group B. At 100 days postirradiation, the severity of the late state was determined by microscopic examination (MICRO) for myocardial fibrosis and determination of myocardial hydroxyproline content (MHP). Myocardial fibrosis was evident in groups A (40%) and B (80%) while none was present in CONT by MICRO. One rabbit in Group B with no fibrosis by MICRO had abnormally increased MHP. MHP was significantly increased in Groups A and B, as compared to CONT (p < 0.01). In addition to less fibrosis by MICRO, Group A demonstrated a significant reduction of MHP when compared to Group B (p < 0.05). Determination of MHP may be superior to MICRO in the detection of the late stage of RIHD. Also, early DEX administration appears to reduce myocardial collagen content (fibrosis) in this experimental model.

Reeves, W.C.; Stryker, J.A.; Abt, A.A.; Chung, C.K.; Whitesell, L.; Zelis, R.

1980-02-01

259

Smad7 foci are present in micronuclei induced by heavy particle radiation.  

PubMed

DNA damage and reactive oxygen species (ROS) generated by ionizing radiation (IR) activate DNA damage response (DDR) and cytokine signaling pathways, including double strand break (DSB) repair and TGF?/Smad signaling pathway. Proteins assembled at IR-induced DSB sites can be visualized as foci, including ?H2AX, 53BP1, ATM and ATF2. Unrepaired DSBs are thought to be one origin of micronuclei (MN), an indicator of genotoxic stress and chromosomal instability. Studies have detected ?H2AX in IR-induced MN, indicating the presence of DSB in MN. Previously we reported that TGF? downstream proteins Smad7 and phospho-Smad2 (pSmad2) co-localized with DDR proteins following radiation. Here we studied the status of Smad7 and pSmad2 in MN post high linear energy transfer (LET) radiation in human normal and cancerous cells. We observed ?H2AX foci in IR-induced MN, whereas 53BP1 and ATF2 were absent. Interestingly, Smad7 foci, but not pSmad2, were detectable in both spontaneous and IR-induced MN. We compared the effect of particle track structures on the yield of MN using 5.6MeV/u boron (B) and 600MeV/u iron (Fe) particles with similar LET (200 and 180keV/?m, respectively) in human fibroblasts. The frequency of MN induced by B was lower than that by Fe particles, albeit the proportion of Smad7-positive to Smad7-negative MN remained constant. An increased frequency of spontaneous MN, with slightly higher ratio of Smad7 or ?H2AX positive, was found in human prostate cancer cells (PC3) compared to normal cells. 24h after 1Gy of Fe particles exposure, the yield of MN increased, and the majority (?70%) carried ?H2AX and Smad7. Phospho-ATM (Ser1981) foci were found in both spontaneous and IR-induced MN in PC3 cells, displaying a much lower frequency compared to ?H2AX and Smad7. Our data suggest a unique role of Smad7 in IR-induced MN formation, which may associate with DNA repair, apoptosis and genomic instability. PMID:23643526

Wang, Minli; Saha, Janapriya; Cucinotta, Francis A

2013-08-30

260

Oral Transmissibility of Prion Disease Is Enhanced by Binding to Soil Particles  

PubMed Central

Soil may serve as an environmental reservoir for prion infectivity and contribute to the horizontal transmission of prion diseases (transmissible spongiform encephalopathies [TSEs]) of sheep, deer, and elk. TSE infectivity can persist in soil for years, and we previously demonstrated that the disease-associated form of the prion protein binds to soil particles and prions adsorbed to the common soil mineral montmorillonite (Mte) retain infectivity following intracerebral inoculation. Here, we assess the oral infectivity of Mte- and soil-bound prions. We establish that prions bound to Mte are orally bioavailable, and that, unexpectedly, binding to Mte significantly enhances disease penetrance and reduces the incubation period relative to unbound agent. Cox proportional hazards modeling revealed that across the doses of TSE agent tested, Mte increased the effective infectious titer by a factor of 680 relative to unbound agent. Oral exposure to Mte-associated prions led to TSE development in experimental animals even at doses too low to produce clinical symptoms in the absence of the mineral. We tested the oral infectivity of prions bound to three whole soils differing in texture, mineralogy, and organic carbon content and found soil-bound prions to be orally infectious. Two of the three soils increased oral transmission of disease, and the infectivity of agent bound to the third organic carbon-rich soil was equivalent to that of unbound agent. Enhanced transmissibility of soil-bound prions may explain the environmental spread of some TSEs despite the presumably low levels shed into the environment. Association of prions with inorganic microparticles represents a novel means by which their oral transmission is enhanced relative to unbound agent.

Johnson, Christopher J; Pedersen, Joel A; Chappell, Rick J; McKenzie, Debbie; Aiken, Judd M

2007-01-01

261

The Effect of Surface Induced Flows on Bubble and Particle Aggregation  

NASA Technical Reports Server (NTRS)

Almost 20 years have elapsed since a phenomenon called "radial specific coalescence" was identified. During studies of electrolytic oxygen evolution from the back side of a vertically oriented, transparent tin oxide electrode in alkaline electrolyte, one of the authors (Sides) observed that large "collector" bubbles appeared to attract smaller bubbles. The bubbles moved parallel to the surface of the electrode, while the electric field was normal to the electrode surface. The phenomenon was reported but not explained. More recently self ordering of latex particles was observed during electrophoretic deposition at low DC voltages likewise on a transparent tin oxide electrode. As in the bubble work, the field was normal to the electrode while the particles moved parallel to it. Fluid convection caused by surface induced flows (SIF) can explain these two apparently different experimental observations: the aggregation of particles on an electrode during electrophoretic deposition, and a radial bubble coalescence pattern on an electrode during electrolytic gas evolution. An externally imposed driving force (the gradient of electrical potential or temperature), interacting with the surface of particles or bubbles very near a planar conducting surface, drives the convection of fluid that causes particles and bubbles to approach each other on the electrode.

Guelcher, Scott A.; Solomentsev, Yuri E.; Anderson, John L.; Boehmer, Marcel; Sides, Paul J.

1999-01-01

262

Enveloped virus-like particle expression of human cytomegalovirus glycoprotein B antigen induces antibodies with potent and broad neutralizing activity.  

PubMed

A prophylactic vaccine to prevent the congenital transmission of human cytomegalovirus (HCMV) in newborns and to reduce life-threatening disease in immunosuppressed recipients of HCMV-infected solid organ transplants is highly desirable. Neutralizing antibodies against HCMV confer significant protection against infection, and glycoprotein B (gB) is a major target of such neutralizing antibodies. However, one shortcoming of past HCMV vaccines may have been their failure to induce high-titer persistent neutralizing antibody responses that prevent the infection of epithelial cells. We used enveloped virus-like particles (eVLPs), in which particles were produced in cells after the expression of murine leukemia virus (MLV) viral matrix protein Gag, to express either full-length CMV gB (gB eVLPs) or the full extracellular domain of CMV gB fused with the transmembrane and cytoplasmic domains from vesicular stomatitis virus (VSV)-G protein (gB-G eVLPs). gB-G-expressing eVLPs induced potent neutralizing antibodies in mice with a much greater propensity toward epithelial cell-neutralizing activity than that induced with soluble recombinant gB protein. An analysis of gB antibody binding titers and T-helper cell responses demonstrated that high neutralizing antibody titers were not simply due to enhanced immunogenicity of the gB-G eVLPs. The cells transiently transfected with gB-G but not gB plasmid formed syncytia, consistent with a prefusion gB conformation like those of infected cells and viral particles. Two of the five gB-G eVLP-induced monoclonal antibodies we examined in detail had neutralizing activities, one of which possessed particularly potent epithelial cell-neutralizing activity. These data differentiate gB-G eVLPs from gB antigens used in the past and support their use in a CMV vaccine candidate with improved neutralizing activity against epithelial cell infection. PMID:24334684

Kirchmeier, Marc; Fluckiger, Anne-Catherine; Soare, Catalina; Bozic, Jasminka; Ontsouka, Barthelemy; Ahmed, Tanvir; Diress, Abebaw; Pereira, Lenore; Schödel, Florian; Plotkin, Stanley; Dalba, Charlotte; Klatzmann, David; Anderson, David E

2014-02-01

263

Fine ambient particles induce oxidative stress and metal binding genes in human alveolar macrophages.  

PubMed

Exposure to pollutant particles increased respiratory morbidity and mortality. The alveolar macrophages (AMs) are one cell type in the lung directly exposed to particles. Upon contact with particles, AMs are activated and produce reactive oxygen species, but the scope of this oxidative stress response remains poorly defined. In this study, we determined the gene expression profile in human AMs exposed to particles, and sought to characterize the global response of pro- and antioxidant genes. We exposed AMs obtained by bronchoscopy from normal individuals to Chapel Hill particulate matter of 2.5-microm diameter or smaller (PM(2.5); 1 microg/ml) or vehicle for 4 hours (n = 6 independent samples). mRNAs were extracted, amplified, and hybridized to Agilent human 1A microarray. Significant genes were identified by significance analysis of microarrays (false discovery rate, 10%; P < or = 0.05) and mapped with Gene Ontology in the Database for Annotation, Visualization, and Integrated Discovery. We found 34 and 41 up- and down-regulated genes, respectively; 22 genes (approximately 30%) were involved in metal binding, and 11 were linked to oxidative stress, including up-regulation of five metallothionein (MT)-1 isoforms. Exogenous MT1 attenuated PM(2.5)-induced H2O2 release. PM(2.5) premixed with MT1 stimulated less H2O2 release. Knockdown of MT1F gene increased PM(2.5)-induced H2O2 release. PM(2.5) at 1 microg/ml did not increase H2O2 release. Mount St. Helens PM(2.5) and acid-extracted Chapel Hill PM(2.5), both poor in metals, did not induce MT1F or H2O2 release. Our results show that PM(2.5) induced a gene expression profile prevalent with genes related to metal binding and oxidative stress in human AMs, independent of oxidative stress. Metals associated with PM may play an important role in particle-induced gene changes. PMID:19251948

Huang, Yuh-Chin T; Li, Zhuowei; Carter, Jacqueline D; Soukup, Joleen M; Schwartz, David A; Yang, Ivana V

2009-11-01

264

Fine Ambient Particles Induce Oxidative Stress and Metal Binding Genes in Human Alveolar Macrophages  

PubMed Central

Exposure to pollutant particles increased respiratory morbidity and mortality. The alveolar macrophages (AMs) are one cell type in the lung directly exposed to particles. Upon contact with particles, AMs are activated and produce reactive oxygen species, but the scope of this oxidative stress response remains poorly defined. In this study, we determined the gene expression profile in human AMs exposed to particles, and sought to characterize the global response of pro- and antioxidant genes. We exposed AMs obtained by bronchoscopy from normal individuals to Chapel Hill particulate matter of 2.5-?m diameter or smaller (PM2.5; 1 ?g/ml) or vehicle for 4 hours (n = 6 independent samples). mRNAs were extracted, amplified, and hybridized to Agilent human 1A microarray. Significant genes were identified by significance analysis of microarrays (false discovery rate, 10%; P ? 0.05) and mapped with Gene Ontology in the Database for Annotation, Visualization, and Integrated Discovery. We found 34 and 41 up- and down-regulated genes, respectively; 22 genes (?30%) were involved in metal binding, and 11 were linked to oxidative stress, including up-regulation of five metallothionein (MT)-1 isoforms. Exogenous MT1 attenuated PM2.5-induced H2O2 release. PM2.5 premixed with MT1 stimulated less H2O2 release. Knockdown of MT1F gene increased PM2.5-induced H2O2 release. PM2.5 at 1 ?g/ml did not increase H2O2 release. Mount St. Helens PM2.5 and acid-extracted Chapel Hill PM2.5, both poor in metals, did not induce MT1F or H2O2 release. Our results show that PM2.5 induced a gene expression profile prevalent with genes related to metal binding and oxidative stress in human AMs, independent of oxidative stress. Metals associated with PM may play an important role in particle-induced gene changes.

Huang, Yuh-Chin T.; Li, Zhuowei; Carter, Jacqueline D.; Soukup, Joleen M.; Schwartz, David A.; Yang, Ivana V.

2009-01-01

265

Particle disease: Biologic mechanisms of periprosthetic osteolysis in total hip arthroplasty  

PubMed Central

Numerous studies provide detailed insight into the triggering and amplification mechanisms of the inflammatory response associated with prosthetic wear particles, promoting final dominance of bone resorption over bone formation in multiple bone multicellular units around an implant. In fact, inflammation is a highly regulated process tightly linked to simultaneous stimulation of tissue protective and regenerative mechanisms in order to prevent collateral damage of periprosthetic tissues. A variety of cytokines, chemokines, hormones and specific cell populations, including macrophages, dendritic and stem cells, attempt to balance tissue architecture and minimize inflammation. Based on this fact, we postulate that the local tissue homeostatic mechanisms more effectively regulate the pro-inflammatory/pro-osteolytic cells/pathways in patients with none/mild periprosthetic osteolysis (PPOL) than in patients with severe PPOL. In this line of thinking, ‘particle disease theory’ can be understood, at least partially, in terms of the failure of local tissue homeostatic mechanisms. As a result, we envision focusing current research on homeostatic mechanisms in addition to traditional efforts to elucidate details of pro-inflammatory/pro-osteolytic pathways. We believe this approach could open new avenues for research and potential therapeutic strategies.

Gallo, Jiri; Goodman, Stuart B; Konttinen, Yrjo T; Raska, Milan

2013-01-01

266

Assembly and Biological and Immunological Properties of Newcastle Disease Virus-Like Particles?  

PubMed Central

Virus-like particles (VLPs) released from avian cells expressing the Newcastle disease virus (NDV) strain AV proteins NP, M, HN (hemagglutinin-neuraminidase), and F were characterized. The VLP-associated HN and F glycoproteins directed the attachment of VLPs to cell surfaces and fusion of VLP membranes with red blood cell membranes, indicating that they were assembled into VLPs in an authentic conformation. These particles were quantitatively prepared and used as an immunogen, without adjuvant, in BALB/c mice. The resulting immune responses, detected by enzyme-linked immunosorbent assay (ELISA), virus neutralization, and intracellular cytokine staining, were comparable to the responses to equivalent amounts of inactivated NDV vaccine virus. HN and F proteins from another strain of NDV, strain B1, could be incorporated into these VLPs. Foreign peptides were incorporated into these VLPs when fused to the NP or HN protein. The ectodomain of a foreign glycoprotein, the Nipah virus G protein, fused to the NDV HN protein cytoplasmic and transmembrane domains was incorporated into ND VLPs. Thus, ND VLPs are a potential NDV vaccine candidate. They may also serve as a platform to construct vaccines for other pathogens.

McGinnes, Lori W.; Pantua, Homer; Laliberte, Jason P.; Gravel, Kathryn A.; Jain, Surbhi; Morrison, Trudy G.

2010-01-01

267

Mechanisms of action of inhaled fibers, particles and nanoparticles in lung and cardiovascular diseases  

PubMed Central

Background A symposium on the mechanisms of action of inhaled airborne particulate matter (PM), pathogenic particles and fibers such as silica and asbestos, and nanomaterials, defined as synthetic particles or fibers less than 100 nm in diameter, was held on October 27 and 28, 2005, at the Environmental Protection Agency (EPA) Conference Center in Research Triangle Park, North Carolina. The meeting was the eighth in a series of transatlantic conferences first held in Penarth, Wales, at the Medical Research Council Pneumoconiosis Unit (1979), that have fostered long-standing collaborations between researchers in the fields of mineralogy, cell and molecular biology, pathology, toxicology, and environmental/occupational health. Results The goal of this meeting, which was largely supported by a conference grant from the NHLBI, was to assemble a group of clinical and basic research scientists who presented and discussed new data on the mechanistic effects of inhaled particulates on the onset and development of morbidity and mortality in the lung and cardiovascular system. Another outcome of the meeting was the elucidation of a number of host susceptibility factors implicated in adverse health effects associated with inhaled pathogenic particulates. Conclusion New models and data presented supported the paradigm that both genetic and environmental (and occupational) factors affect disease outcomes from inhaled particulates as well as cardiopulmonary responses. These future studies are encouraged to allow the design of appropriate strategies for prevention and treatment of particulate-associated morbidity and mortality, especially in susceptible populations.

Mossman, Brooke T; Borm, Paul J; Castranova, Vincent; Costa, Daniel L; Donaldson, Kenneth; Kleeberger, Steven R

2007-01-01

268

Brain signaling and behavioral responses induced by exposure to (56)Fe-particle radiation  

NASA Technical Reports Server (NTRS)

Previous experiments have demonstrated that exposure to 56Fe-particle irradiation (1.5 Gy, 1 GeV) produced aging-like accelerations in neuronal and behavioral deficits. Astronauts on long-term space flights will be exposed to similar heavy-particle radiations that might have similar deleterious effects on neuronal signaling and cognitive behavior. Therefore, the present study evaluated whether radiation-induced spatial learning and memory behavioral deficits are associated with region-specific brain signaling deficits by measuring signaling molecules previously found to be essential for behavior [pre-synaptic vesicle proteins, synaptobrevin and synaptophysin, and protein kinases, calcium-dependent PRKCs (also known as PKCs) and PRKA (PRKA RIIbeta)]. The results demonstrated a significant radiation-induced increase in reference memory errors. The increases in reference memory errors were significantly negatively correlated with striatal synaptobrevin and frontal cortical synaptophysin expression. Both synaptophysin and synaptobrevin are synaptic vesicle proteins that are important in cognition. Striatal PRKA, a memory signaling molecule, was also significantly negatively correlated with reference memory errors. Overall, our findings suggest that radiation-induced pre-synaptic facilitation may contribute to some previously reported radiation-induced decrease in striatal dopamine release and for the disruption of the central dopaminergic system integrity and dopamine-mediated behavior.

Denisova, N. A.; Shukitt-Hale, B.; Rabin, B. M.; Joseph, J. A.

2002-01-01

269

Studies of fast-ion transport induced by energetic particle modes using fast-particle diagnostics with high time resolution in CHS  

Microsoft Academic Search

The purpose of this work is to reveal the effects of the energetic particle mode (EPM) on fast-ion transport and consequent fast-ion loss in the compact helical system (CHS). For this purpose, fast particle diagnostics capable of following fast events originating from the EPM (f < 100 kHz) and from the toroidicity-induced Alfvén eigenmode (TAE) (f = 100-200 kHz) are

M. Isobe; K. Toi; H. Matsushita; K. Goto; C. Suzuki; K. Nagaoka; N. Nakajima; S. Yamamoto; S. Murakami; A. Shimizu; Y. Yoshimura; T. Akiyama; T. Minami; M. Nishiura; S. Nishimura; D. S. Darrow; D. A. Spong; K. Shinohara; M. Sasao; K. Matsuoka; S. Okamura

2006-01-01

270

Altered particle size distribution of apolipoprotein A=l=containing lipoproteins in subjects with coronary artery disease  

Microsoft Academic Search

Plasma high density lipoproteins (HDL) can be separated into two subpopulations of apolipoprotein A-I- containing particles: those that also contain apoA-I1 ( Lp(A1 w AH)) and those that do not (Lp(AI w\\/o AH)). These particles were isolated by immunoaffinity Chromatography from 17 men (9 normolipidemic (NL), 8 hyperlipidemic (HL)) with sympto- matic coronary artery disease (CAD), from 17 NL men

Marian C. Cheung; B. Greg Brown; Anitra C. Wolf; John J. Albers

271

A Majority of Infectious Newcastle Disease Virus Particles Contain a Single Genome, while a Minority Contain Multiple Genomes  

PubMed Central

Paramyxoviruses produce pleiomorphic particles containing variable amounts of genetic material that correlate with virion diameter by electron microscopy. However, the infectious nature of these particles is unknown, and functional genomes are indistinguishable from defective RNA. A quantitative approach to paramyxovirus packaging revealed a majority of infectious Newcastle disease viruses contain one functional genome. Virions encapsidating two or three genomes (approximately 25% of total) were also observed by utilizing three different recombinant viruses expressing unique fluorescent reporters.

Goff, Peter H.; Gao, Qinshan

2012-01-01

272

Adenosine A2A Receptor Activation Prevents Wear Particle-Induced Osteolysis  

PubMed Central

Prosthesis loosening, associated with wear-particle–induced inflammation and osteoclast-mediated bone destruction, is a common cause for joint implant failure, leading to revision surgery. Adenosine A2A receptors (A2AR) mediate potent anti-inflammatory effects in many tissues and prevent osteoclast differentiation. We tested the hypothesis that an A2AR agonist could reduce osteoclast-mediated bone resorption in a murine calvaria model of wear-particle–induced bone resorption. C57Bl/6 and A2A knockout (A2ARKO) mice received ultrahigh-molecular weight polyethylene particles (UHMWPE) and were treated daily with either saline or the A2AR agonist CGS21680. After 2 weeks, micro-computed tomography of calvaria demonstrated that CGS21680 reduced particle-induced bone pitting and porosity in a dose-dependent manner, increasing cortical bone and bone volume compared to control mice. Histological examination demonstrated diminished inflammation after treatment with CGS21680. In A2AKO mice, CGS21680 did not affect osteoclast-mediated bone resorption or inflammation. Levels of bone-resorption markers receptor activator of nuclear factor-kB (RANK), RANK ligand (RANKL), cathepsin K, CD163, and osteopontin were reduced following CGS21680 treatment, together with a reduction in osteoclasts. Secretion of interleukin 1? (IL-1?) and TNF? was significantly decreased, whereas IL-10 was markedly increased in bone by CGS21680. These results in mice suggest that site-specific delivery of an adenosine A2AR agonist could enhance implant survival, delaying or eliminating the need for revision arthroplastic surgery.

Mediero, Aranzazu; Frenkel, Sally R.; Wilder, Tuere; He, Wenjie; Mazumder, Amitabha; Cronstein, Bruce N.

2012-01-01

273

Modeling fundamental plasma transport and particle-induced emission in a simplified Test Cell  

NASA Astrophysics Data System (ADS)

This work involves the modeling of fundamental plasma physics processes occurring within environments that are similar to that of the discharge and plume regions of electric propulsion devices such as Hall effect thrusters. The research is conducted as a collaborative effort with the Plasma & Space Propulsion Laboratory at the University of California, Los Angeles (UCLA), as part of the University of Michigan/AFRL Center for Excellence in Electric Propulsion (MACEEP). Transport physics, such as particle-particle collisions and particle-induced electron emission, are simulated within the UCLA experimental facility and its representative electric propulsion environment. Simulation methods employed include the direct simulation Monte Carlo (DSMC) and particle-in-cell (PIC) techniques for the kinetic simulation of charged, rarefied species on high-performance computing architectures. Momentum- (MEX) and charge-exchange (CEX) collision cross-section models for Xe and Xe+, both total and differential, are successfully validated at collision energies of ˜1.5 keV within the novel facility. Heavy-species collisional transport models are validated and the importance of scattering anisotropy in this collision-dominated environment is shown. The theory of particle-induced electron emission (PIE) is then investigated in the context of the relevant energies and environments of the UCLA facility and electric propulsion devices and diagnostics. Reduced, semi-empirical models for total yield and emitted electron energy distribution functions that are easily implemented in a DSMC-PIC code are developed for the simulation of secondary-electron emission due to low-energy ions and high-energy atoms, even in the case of incomplete target-material information. These models are important for the characterization of electric propulsion devices due to the problematic nature of low-temperature plasma diagnostic techniques in which the emission of electrons is physically indistinguishable from the collection of ions.

Giuliano, Paul Nicholas

274

particles  

NASA Astrophysics Data System (ADS)

We explore a facile and nontoxic hydrothermal route for synthesis of a Cu2ZnSnS4 nanocrystalline material by using l-cysteine as the sulfur source and ethylenediaminetetraacetic acid (EDTA) as the complexing agent. The effects of the amount of EDTA, the mole ratio of the three metal ions, and the hydrothermal temperature and time on the phase composition of the obtained product have been systematically investigated. The addition of EDTA and an excessive dose of ZnCl2 in the hydrothermal reaction system favor the generation of kesterite Cu2ZnSnS4. Pure kesterite Cu2ZnSnS4 has been synthesized at 180°C for 12 h from the reaction system containing 2 mmol of EDTA at 2:2:1 of Cu/Zn/Sn. It is confirmed by Raman spectroscopy that those binary and ternary phases are absent in the kesterite Cu2ZnSnS4 product. The kesterite Cu2ZnSnS4 material synthesized by the hydrothermal process consists of flower-like particles with 250 to 400 nm in size. It is revealed that the flower-like particles are assembled from single-crystal Cu2ZnSnS4 nanoflakes with ca. 20 nm in size. The band gap of the Cu2ZnSnS4 nanocrystalline material is estimated to be 1.55 eV. The films fabricated from the hierarchical Cu2ZnSnS4 particles exhibit fast photocurrent responses under intermittent visible-light irradiation, implying that they show potentials for use in solar cells and photocatalysis.

Xia, Yu; Chen, Zhihong; Zhang, Zhengguo; Fang, Xiaoming; Liang, Guozheng

2014-05-01

275

Non-random distribution of DNA double-strand breaks induced by particle irradiation  

NASA Technical Reports Server (NTRS)

Induction of DNA double-strand breaks (dsbs) in mammalian cells is dependent on the spatial distribution of energy deposition from the ionizing radiation. For high LET particle radiations the primary ionization sites occur in a correlated manner along the track of the particles, while for X-rays these sites are much more randomly distributed throughout the volume of the cell. It can therefore be expected that the distribution of dsbs linearly along the DNA molecule also varies with the type of radiation and the ionization density. Using pulsed-field gel and conventional gel techniques, we measured the size distribution of DNA molecules from irradiated human fibroblasts in the total range of 0.1 kbp-10 Mbp for X-rays and high LET particles (N ions, 97 keV/microns and Fe ions, 150 keV/microns). On a mega base pair scale we applied conventional pulsed-field gel electrophoresis techniques such as measurement of the fraction of DNA released from the well (FAR) and measurement of breakage within a specific NotI restriction fragment (hybridization assay). The induction rate for widely spaced breaks was found to decrease with LET. However, when the entire distribution of radiation-induced fragments was analysed, we detected an excess of fragments with sizes below about 200 kbp for the particles compared with X-irradiation. X-rays are thus more effective than high LET radiations in producing large DNA fragments but less effective in the production of smaller fragments. We determined the total induction rate of dsbs for the three radiations based on a quantitative analysis of all the measured radiation-induced fragments and found that the high LET particles were more efficient than X-rays at inducing dsbs, indicating an increasing total efficiency with LET. Conventional assays that are based only on the measurement of large fragments are therefore misleading when determining total dsb induction rates of high LET particles. The possible biological significance of this non-randomness for dsb induction is discussed.

Lobrich, M.; Cooper, P. K.; Rydberg, B.; Chatterjee, A. (Principal Investigator)

1996-01-01

276

Near-infrared-induced heating of confined water in polymeric particles for efficient payload release.  

PubMed

Near-infrared (NIR) light-triggered release from polymeric capsules could make a major impact on biological research by enabling remote and spatiotemporal control over the release of encapsulated cargo. The few existing mechanisms for NIR-triggered release have not been widely applied because they require custom synthesis of designer polymers, high-powered lasers to drive inefficient two-photon processes, and/or coencapsulation of bulky inorganic particles. In search of a simpler mechanism, we found that exposure to laser light resonant with the vibrational absorption of water (980 nm) in the NIR region can induce release of payloads encapsulated in particles made from inherently non-photo-responsive polymers. We hypothesize that confined water pockets present in hydrated polymer particles absorb electromagnetic energy and transfer it to the polymer matrix, inducing a thermal phase change. In this study, we show that this simple and highly universal strategy enables instantaneous and controlled release of payloads in aqueous environments as well as in living cells using both pulsed and continuous wavelength lasers without significant heating of the surrounding aqueous solution. PMID:24717072

Viger, Mathieu L; Sheng, Wangzhong; Doré, Kim; Alhasan, Ali H; Carling, Carl-Johan; Lux, Jacques; de Gracia Lux, Caroline; Grossman, Madeleine; Malinow, Roberto; Almutairi, Adah

2014-05-27

277

Induced pluripotent stem cells — opportunities for disease modelling and drug discovery  

Microsoft Academic Search

The ability to generate induced pluripotent stem cells (iPSCs) from patients, and an increasingly refined capacity to differentiate these iPSCs into disease-relevant cell types, promises a new paradigm in drug development — one that positions human disease pathophysiology at the core of preclinical drug discovery. Disease models derived from iPSCs that manifest cellular disease phenotypes have been established for several

Marica Grskovic; Ashkan Javaherian; Berta Strulovici; George Q. Daley

2011-01-01

278

Transport of particles by a thermally induced gradient of the order parameter in nematic liquid crystals.  

PubMed

We demonstrate manipulation and transport of microparticles and even fluorescent molecules by the thermally induced gradient of the order parameter in the nematic liquid crystal. We use IR light absorption of the tightly focused beam of laser tweezers to heat locally a thin layer of the nematic liquid crystal by several degrees. This creates a spatial gradient of temperature of the nematic liquid crystal over separations of several tens of micrometers. We show that a dipolar colloidal particle is attracted into the hot spot of the laser tweezers. The depth of the trapping potential scales linearly with particle radius, indicating that the trapping mechanism is due to elastic self-energy of the distorted nematic liquid crystal around the particle and softening of the elasticity with increased temperature of the liquid crystal. We also demonstrate that this thermal trapping mechanism is efficient down to the nanoscale, as fluorescent molecules are also transported into hotter regions of the liquid crystal. This effect is absent in the isotropic phase, which calls into question particle transport due to the Soret effect. PMID:23848699

Škarabot, M; Lokar, Ž; Muševi?, I

2013-06-01

279

Quantification of nanoparticles in aqueous food matrices using Particle-Induced X-ray Emission.  

PubMed

Nanoparticles (NPs) of SiO(2) (15 nm) or Ag (20 - 40 nm) were dispersed in water, coffee and milk at several aqueous dilutions. The NPs dispersions concentrations were quantified with an ion beam technique: Particle-Induced X-ray Emission. Additional measurements in relation to the state of the NPs dispersions were done: particle size distribution by centrifuge liquid sedimentation and the extreme surface composition by X-ray photoelectron spectroscopy. The particle size distribution of SiO(2) and Ag NPs dispersions in water and Ag NPs in coffee remained mostly as primary particles with hydrodynamic diameters close to the reported pristine NPs diameter. SiO(2) NPs agglomerated in coffee. In milk, both NPs presented an adsorption with milk lipids. Extreme surface composition corroborated adsorption in milk and showed that SiO(2) agglomerates adsorb some coffee components. A linear tendency in the measurement of the concentration dilutions of all dispersions was measured, and a lack of media influence in the slope of each curve was found. Limits of detection with the current setup were estimated at 0.5 and 0.3 mg/ml for SiO(2) and Ag NPs, respectively. PMID:22411536

Lozano, Omar; Mejia, Jorge; Tabarrant, Tijani; Masereel, Bernard; Dogné, Jean-Michel; Toussaint, Olivier; Lucas, Stéphane

2012-07-01

280

Model for alpha particle induced nuclear reactions: 93Nb(alpha,xalphaypzn) from 40-140 MeV  

Microsoft Academic Search

A comprehensive model is introduced for alpha particle induced nuclear reactions. Five different mechanisms are examined and discussed. These include inelastic scattering of the incident alpha particle, nucleon pickup, binary fragmentation, dissolution of the alpha in the nuclear field, and preequilibrium processes initiated by alpha-nucleon collisions. A series of experiments was performed to measure the excitation functions of many nuclides

Ettore Gadioli; Enrica Gadioli-Erba; James J. Hogan; Barbara V. Jacak

1984-01-01

281

Effect of phase memory under collisions on field work and light-induced drift of gas particles  

Microsoft Academic Search

The influence of phase memory under collisions on the field work and the light induced drift (LID) effect of two-level gas particles is studied. It is shown that the phase memory effects may lead to the case where about half of the particles interacting with radiation amplify the incident radiation. The integral absorption coefficient for this remains positive due to

F. Kh Gel'mukhanov; A. I. Parkhomenko

1991-01-01

282

The role of induced pluripotent stem cells in regenerative medicine: neurodegenerative diseases  

PubMed Central

Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and Friedreich's ataxia are the most common human neurodegenerative diseases pathologically characterized by a progressive and specific loss of certain neuronal populations. The exact mechanisms of neuronal cell death in these diseases are unclear, although some forms of the diseases are inherited and genes causing these diseases have been identified. Currently there are no effective clinical therapies for many of these diseases. The recently acquired ability to reprogram human adult somatic cells to induced pluripotent stem cells (iPSCs) in culture may provide a powerful tool for in vitro neurodegenerative disease modeling and an unlimited source for cell replacement therapy. In the present review, we summarize recent progress on iPSC generation and differentiation into neuronal cell types and discuss the potential application for in vitro disease mechanism study and in vivo cell replacement therapy.

2011-01-01

283

Avian adenovirus CELO recombinants expressing VP2 of infectious bursal disease virus induce protection against bursal disease in chickens  

Microsoft Academic Search

To develop a CELO virus vector that can induce protection against infectious bursal disease, CELO viruses expressing the host-protective antigen VP2 of infectious bursal disease virus (IBDV) were constructed. In the engineered recombinants, the VP2 gene (the 441-first codons of the IBDA polyprotein) was placed under the control of the CMV promoter. Two positions in the CELO genome were chosen

Achille Francois; Christophe Chevalier; Bernard Delmas; Nicolas Eterradossi; Didier Toquin; Gaëlle Rivallan; Patrick Langlois

2004-01-01

284

CD28 Costimulatory Blockade Exacerbates Disease Severity and Accelerates Epitope Spreading in a Virus-Induced Autoimmune Disease  

Microsoft Academic Search

Theiler's murine encephalomyelitis virus (TMEV) is a natural mouse pathogen which causes a lifelong persistent infection of the central nervous system (CNS) accompanied by T-cell-mediated myelin destruction leading to chronic, progressive hind limb paralysis. TMEV-induced demyelinating disease (TMEV-IDD) is considered to be a highly relevant animal model for the human autoimmune disease multiple sclerosis (MS), which is thought to be

KATHERINE L. NEVILLE; MAURO C. DAL CANTO; JEFFREY A. BLUESTONE; STEPHEN D. MILLER

2000-01-01

285

Pressure-Induced Crack Propagation Behavior in a Particle-Reinforced Composite  

NASA Astrophysics Data System (ADS)

An experimental investigation was conducted to study pressure-induced crack propagation behavior of a particle-reinforced composite (PRC) under various pressurization rate conditions. A pre-cracked specimen of a metallic particle-reinforced rubbery composite was fixed in a holder which is installed in a windowed test chamber, and then high compressed nitrogen gas rapidly pressurized the chamber and the specimen. Chamber pressures were measured during the test, and detailed sequences of crack initiation and propagation were recorded by a high-speed digital video camera. Pressure vs. time traces were obtained from test results, and pressurization rates were defined from them. The crack propagation contours and lengths under various pressurization rates were observed through a stereoscopic microscope. Also, a progression of the crack initiation and propagation was observed by the sequences of the crack recorded by the high-speed digital video camera.

Ha, Jae-Seok; Kim, Jae-Hoon

286

Comparative acute lung inflammation induced by atmospheric PM and size-fractionated tire particles.  

PubMed

A comparison of the effects produced by size-fractionated tire particles (TP10 and TP2.5) and similar-sized urban particulate matter (PM10 and PM2.5), collected in Milan in 2007, on the lungs of mice has been performed. The focus is on early acute lung responses following intratracheal instillation of aerosolized particles at a 3-h recovery period. Together with bronchoalveolar lavage (BAL) conventional endpoints like total and differential cell counts, total protein, alkaline phosphatase, lactate dehydrogenase and pro-inflammatory cytokines (TNF-alpha, MIP-2), the expression of different stress protein markers (caspase8, Hsp70, H0-1, NF-kB) was evaluated 3h after particle instillation into Balb/c mice. The TP2.5 fraction reached the alveolar spaces and produced an acute inflammatory response as evidenced by increased LDH and AP activities, total protein and Hsp70 content. TNF-alpha and MIP-2 production was significantly increased and polymorphonuclear neutrophils (PMN) recruitment was apparent. The TP10 fraction distributed mainly in the bronchial district and the only modified BAL parameter was the expression of MIP-2. PM2.5 induced an inflammatory response lesser in magnitude than that produced by PM10 fraction. The TNF-alpha increase was not significant, and HO-1, though significantly increased with respect to the control, was unable to reduce NF-kB activation, suggesting a role of the endotoxin component of PM in stimulating a pro-inflammatory limited response. This response was maximized by the PM10 that induced a significant increase in MIP-2, TNF-alpha, and HO-1. Lung immunohistochemistry showed fine particles, TPs in particular, being able to deeply penetrate and rapidly induce inflammatory events in the parenchyma, even involving endothelial cells, while PM10 produced a strong pro-inflammatory response mediated by the bronchiolar cells and residential macrophages of the proximal alveolar sacs, likely as a consequence of its larger dimension and endotoxin content. These results provide evidence of variable inflammatory mechanisms in mouse lungs in response to both urban PM and tire particles. PMID:20621170

Mantecca, Paride; Farina, Francesca; Moschini, Elisa; Gallinotti, Daniele; Gualtieri, Maurizio; Rohr, Annette; Sancini, Giulio; Palestini, Paola; Camatini, Marina

2010-10-01

287

Long-term changes in amphetamine-induced reinforcement and aversion in rats following exposure to 56Fe particle  

NASA Technical Reports Server (NTRS)

Exposing rats to heavy particles produces alterations in the functioning of dopaminergic neurons and in the behaviors that depend upon the integrity of the dopaminergic system. Two of these dopamine-dependent behaviors include amphetamine-induced reinforcement, measure using the conditioned place preference procedure, and amphetamine-induced reinforcement, measured using the conditioned place preference procedure, and amphetamine-induced aversion, measured using the conditioned taste aversion. Previous research has shown that exposing rats to 1.0 Gy of 1GeV/n 56Fe particles produced a disruption of an amphetamine-induced taste aversion 3 days following exposure, but produced an apparent enhancement of the aversion 112 days following exposure. The present experiments were designed to provide a further evaluation of these results by examining taste aversion learning 154 days following exposure to 1.0 Gy 56Fe particles and to establish the convergent validity of the taste aversion results by looking at the effects of exposure on the establishment of an amphetamine-induced conditioned place preference 3, 7, and 16 weeks following irradiation. The taste aversion results failed to confirm the apparent enhancement of the amphetamine-induced CTA observed in the prior experiment. However, exposure to 56Fe particles prevented the acquisition of amphetamine-induced place preference at all three-time intervals. The results are interpreted as indicating that exposure to heavy particles can produce long-term changes in behavioral functioning. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

Rabin, B. M.; Joseph, J. A.; Shukitt-Hale, B.

2003-01-01

288

Long-term changes in amphetamine-induced reinforcement and aversion in rats following exposure to 56Fe particle  

NASA Astrophysics Data System (ADS)

Exposing rats to heavy particles produces alterations in the functioning of dopaminergic neurons and in the behaviors that depend upon the integrity of the dopaminergic system. Two of these dopamine-dependent behaviors include amphetamine-induced reinforcement, measure using the conditioned place preference procedure, and amphetamine-induced reinforcement, measured using the conditioned place preference procedure, and amphetamine-induced aversion, measured using the conditioned taste aversion. Previous research has shown that exposing rats to 1.0 Gy of 1GeV/n 56Fe particles produced a disruption of an amphetamine-induced taste aversion 3 days following exposure, but produced an apparent enhancement of the aversion 112 days following exposure. The present experiments were designed to provide a further evaluation of these results by examining taste aversion learning 154 days following exposure to 1.0Gy 56Fe particles and to establish the convergent validity of the taste aversion results by looking at the effects of exposure on the establishment of an amphetamine-induced conditioned place preference 3, 7, and 16 weeks following irradiation. The taste aversion results failed to confirm the apparent enhancement of the amphetamine-induced CTA observed in the prior experiment. However, exposure to 56Fe particles prevented the acquisition of amphetamine-induced place preference at all three-time intervals. The results are interpreted as indicating that exposure to heavy particles can produce long-term changes in behavioral functioning.

Rabin, B. M.; Joseph, J. A.; Shukitt-Hale, B.

289

Analytical Applications Of Particle-Induced X-Ray Emission (PIXE)  

NASA Astrophysics Data System (ADS)

In this paper a complex study of the capabilities of Particle-Induced X-ray Emission (PIXE) technique for the determination of major, minor and trace constituents of metallurgical, biological and environmental samples has been done. The elements identified in the metallurgical samples (steels) using PIXE were: K, Ca, V, Cr, Mn, Fe, Co, Cu, Ni, Zn, W, Ga, As, Pb, Mo, Rb, In, Rh, Zr, Pd, Nb, Sn and Sb. In the investigated biological and environmental samples (vegetals leaves, soil and mosses) PIXE analysis allowed determination of: S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Hg and Pb.

Popescu, I. V.; Ene, A.; Stihi, C.; Bancuta, A.; Dima, G.; Badica, T.; Ghisa, V.

2007-04-01

290

Analytical Applications Of Particle-Induced X-Ray Emission (PIXE)  

SciTech Connect

In this paper a complex study of the capabilities of Particle-Induced X-ray Emission (PIXE) technique for the determination of major, minor and trace constituents of metallurgical, biological and environmental samples has been done. The elements identified in the metallurgical samples (steels) using PIXE were: K, Ca, V, Cr, Mn, Fe, Co, Cu, Ni, Zn, W, Ga, As, Pb, Mo, Rb, In, Rh, Zr, Pd, Nb, Sn and Sb. In the investigated biological and environmental samples (vegetals leaves, soil and mosses) PIXE analysis allowed determination of: S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Hg and Pb.

Popescu, I. V.; Stihi, C.; Bancuta, A.; Dima, G. ['Valahia' University of Targoviste, Targoviste (Romania); Ene, A. ['Dunarea de Jos' University of Galati, Galati (Romania); Badica, T. ['Horia Hulubei' NIPNE, Bucharest (Romania); Ghisa, V. ['Ovidius' University of Constanta, Constanta (Romania)

2007-04-23

291

Intra-tumor distribution of metallofullerene using micro-particle induced X-ray emission (PIXE).  

PubMed

To clarify the intra tumor distribution of gadlinium containing fullerene (Gd@C82), micro particle induced X-ray emission (Micro-PIXE) analysis were performed. The tumor bearing BALB/c mice were injected Gd@C82 and subcutaneous tumors were taken from 48h after the intravenous injection. Using the Micro-PIXE method, we could visualize Gd intra tumor distribution. Therefore our results indicate the possibility that Micro-PIXE is useful technique for imaging the bioditribution of Gd, and Gd@C82 is potentially useful Gd carrier for NCT. PMID:24491681

Yamamoto, Yohei; Yamamoto, Tetsuya; Horiguchi, Yukichi; Shirakawa, Makoto; Satoh, Takahiro; Koka, Masashi; Nagasaki, Yukio; Nakai, Kei; Matsumura, Akira

2014-06-01

292

Analysis of radiation-induced small Cu particle cluster formation in aqueous CuCl2  

USGS Publications Warehouse

Radition-induced small Cu particle cluster formation in aqueous CuCl2 was analyzed. It was noticed that nearest neighbor distance increased with the increase in the time of irradiation. This showed that the clusters approached the lattice dimension of bulk copper. As the average cluster size approached its bulk dimensions, an increase in the nearest neighbor coordination number was found with the decrease in the surface to volume ratio. Radiolysis of water by incident x-ray beam led to the reduction of copper ions in the solution to themetallic state.

Jayanetti, S.; Mayanovic, R. A.; Anderson, A. J.; Bassett, W. A.; Chou, I. -M.

2001-01-01

293

Continuum- and particle-based modeling of shapes and dynamics of red blood cells in health and disease  

PubMed Central

We review recent advances in multiscale modeling of the mechanics of healthy and diseased red blood cells (RBCs), and blood flow in the microcirculation. We cover the traditional continuum-based methods but also particle-based methods used to model both the RBCs and the blood plasma. We highlight examples of successful simulations of blood flow including malaria and sickle cell anemia.

Li,, Xuejin; Vlahovska, Petia M.

2012-01-01

294

Dieldrin-Induced Neurotoxicity: Relevance to Parkinson's Disease Pathogenesis  

Microsoft Academic Search

Parkinson's disease (PD) is increasingly recognized as a neurodegenerative disorder strongly associated with environmental chemical exposures. Recent epidemiological data demonstrate that environmental risk factors may play a dominant role as compared to genetic factors in the etiopathogenesis of idiopathic Parkinson's disease. Identification of key genetic defects such as alpha-synuclein and parkin mutations in PD also underscores the important role of

Anumantha G. Kanthasamy; Masashi Kitazawa; Arthi Kanthasamy; Vellareddy Anantharam

2005-01-01

295

Evolution of high yielding chickpea varieties, having improved plant type and disease resistance, through induced mutations.  

National Technical Information Service (NTIS)

The breeding programme on the use of induced mutations, in chickpea for genetic variability for better plant type, grain yield and disease resistance has been started. The chickpea mutant variety is one of the leading varieties being extensively grown thr...

M. Sadiq M. Hussan M. A. Haq

1989-01-01

296

Oxidative stress mediates air pollution particle-induced acute lung injury and molecular pathology.  

PubMed

Insight into the mechanism(s) by which ambient air particulate matter (PM) mediates adverse health effects is needed to provide biological plausibility to epidemiological studies demonstrating associations between PM exposure and increased morbidity and mortality. Although in vitro PM studies provide an understanding of mechanisms by which PM affects pulmonary cells, it is difficult to extrapolate from in vitro to in vivo mechanisms of PM-induced lung injury. We examined in vivo mechanisms of lung injury generated by oil combustion particles. Rats were pretreated with dimethylthiourea (DMTU) before intratracheal instillation of residual oil fly ash (ROFA). Animals were examined by bronchoalveolar lavage for biomarkers of lung injury, and lung tissues were examined by immunohistochemical, biochemical, and molecular approaches to identify ROFA-induced alterations in intracellular signaling pathways and proinflammatory gene expression. Significant increases in pulmonary inflammation, cytotoxicity, activation of ERK mitogen-activated protein kinase (MAPK), and increases in mRNA levels encoding macrophage inflammatory protein (MIP)-2, interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, MCP-1 and matrilysin were observed. DMTU pretreatment inhibited ROFA-induced pulmonary inflammation, cytotoxicity, ERK MAPK activation, and cytokine gene expression. Our findings provide coherence with in vitro PM mechanistic information, allow direct in vitro to in vivo extrapolation, and demonstrate a critical role for oxidative stress in ROFA-induced lung injury and associated molecular pathology. PMID:14569496

Roberts, Elizabeth S; Richards, Judy H; Jaskot, Richard; Dreher, Kevin L

2003-11-01

297

Mineral particles of varying composition induce differential chemokine release from epithelial lung cells: importance of physico-chemical characteristics.  

PubMed

Presently, little is known about the potential health effects of mineral particles other than asbestos and quartz. In this study, a human epithelial lung cell line (A549), primary human small airway epithelial cells (SAECs) and primary rat type 2 (T2) cells were exposed to stone quarry particles of two size fractions (<10 and <2.5 microm) from nine different rock samples. The ability to induce the release of chemokines from lung cells was investigated and compared with the particles' mineral and element composition and the amount of soluble elements. The stone particles induced the release of only low levels of interleukin (IL)-8 from A549 cells. In contrast, some of the other particles induced the release of high levels of macrophage inflammatory protein (MIP)-2 from T2 cells, and high levels of IL-8 from SAECs. Differences in particle surface area could account for differences in activity between the <10 and <2.5 microm fractions of six out of the nine rock samples. For two samples the <2.5 microm fraction was most active and for one sample the <10 microm fraction was most active. Content of the mineral plagioclase displayed a strong, negative correlation with the potential to induce MIP-2, whereas the mineral pyroxene was positively correlated with MIP-2 induction. However, neither plagioclase nor pyroxene content was sufficient to explain differences in bioactivity between the particles. No statistically significant correlation was found between the amounts of total or soluble elements and MIP-2 release. In conclusion, the results suggest that mineral particles with a high content of plagioclase have a low potential to induce a pro-inflammatory response. However, a particular mineral or element responsible for eliciting strong increases in chemokine release could not be identified. Thus, at present it appears that analysing mineral and element content is insufficient to predict stone particle bioactivity, and that biological testing is a necessity. PMID:15640311

Ovrevik, J; Myran, T; Refsnes, M; Låg, M; Becher, R; Hetland, R B; Schwarze, P E

2005-04-01

298

Protection of cisplatin-induced spermatotoxicity, DNA damage and chromatin abnormality by selenium nano-particles  

SciTech Connect

Cisplatin (CIS), an anticancer alkylating agent, induces DNA adducts and effectively cross links the DNA strands and so affects spermatozoa as a male reproductive toxicant. The present study investigated the cellular/biochemical mechanisms underlying possible protective effect of selenium nano-particles (Nano-Se) as an established strong antioxidant with more bioavailability and less toxicity, on reproductive toxicity of CIS by assessment of sperm characteristics, sperm DNA integrity, chromatin quality and spermatogenic disorders. To determine the role of oxidative stress (OS) in the pathogenesis of CIS gonadotoxicity, the level of lipid peroxidation (LPO), antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and peroxynitrite (ONOO) as a marker of nitrosative stress (NS) and testosterone (T) concentration as a biomarker of testicular function were measured in the blood and testes. Thirty-two male Wistar rats were equally divided into four groups. A single IP dose of CIS (7 mg/kg) and protective dose of Nano-Se (2 mg/kg/day) were administered alone or in combination. The CIS-exposed rats showed a significant increase in testicular and serum LPO and ONOO level, along with a significant decrease in enzymatic antioxidants levels, diminished serum T concentration and abnormal histologic findings with impaired sperm quality associated with increased DNA damage and decreased chromatin quality. Coadministration of Nano-Se significantly improved the serum T, sperm quality, and spermatogenesis and reduced CIS-induced free radical toxic stress and spermatic DNA damage. In conclusion, the current study demonstrated that Nano-Se may be useful to prevent CIS-induced gonadotoxicity through its antioxidant potential. Highlights: ? Cisplatin (CIS) affects spermatozoa as a male reproductive toxicant. ? Effect of Nano-Se on CIS-induced spermatotoxicity was investigated. ? CIS-exposure induces oxidative sperm DNA damage and impairs steroidogenesis. ? Nano-Se retained sperm quality against CIS-induced free radicals toxic stress.

Rezvanfar, Mohammad Amin; Rezvanfar, Mohammad Ali [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of)] [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza [Department of Pharmaceutical Biotechnology and Biotechnology Research Centre, Faculty of Pharmacy, TUMS, Tehran (Iran, Islamic Republic of)] [Department of Pharmaceutical Biotechnology and Biotechnology Research Centre, Faculty of Pharmacy, TUMS, Tehran (Iran, Islamic Republic of); Ahmadi, Abbas [Department of Histology and Embryology, Faculty of Veterinary Medicine, Urmia University, Urmia (Iran, Islamic Republic of)] [Department of Histology and Embryology, Faculty of Veterinary Medicine, Urmia University, Urmia (Iran, Islamic Republic of); Baeeri, Maryam; Mohammadirad, Azadeh [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of)] [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: mohammad.abdollahi@utoronto.ca [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of)] [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of)

2013-02-01

299

Clinical Features, Pathophysiology, and Treatment of Levodopa-Induced Dyskinesias in Parkinson's Disease  

PubMed Central

Dyskinetic disorders are characterized by excess of motor activity that may interfere with normal movement control. In patients with Parkinson's disease, the chronic levodopa treatment induces dyskinetic movements known as levodopa-induced dyskinesias (LID). This paper analyzed the pathophysiology, clinical manifestations, pharmacological treatments, and surgical procedures to treat hyperkinetic disorders. Surgery is currently the only treatment available for Parkinson's disease that may improve both parkinsonian motor syndrome and LID. However, this paper shows the different mechanisms involved are not well understood.

Guridi, J.; Gonzalez-Redondo, R.; Obeso, J. A.

2012-01-01

300

Targeted Cytoplasmic Irradiation with Alpha Particles Induces Mutations in Mammalian Cells  

NASA Astrophysics Data System (ADS)

Ever since x-rays were shown to induce mutation in Drosophila more than 70 years ago, prevailing dogma considered the genotoxic effects of ionizing radiation, such as mutations and carcinogenesis, as being due mostly to direct damage to the nucleus. Although there was indication that alpha particle traversal through cellular cytoplasm was innocuous, the full impact remained unknown. The availability of the microbeam at the Radiological Research Accelerator Facility of Columbia University made it possible to target and irradiate the cytoplasm of individual cells in a highly localized spatial region. By using dual fluorochrome dyes (Hoechst and Nile Red) to locate nucleus and cellular cytoplasm, respectively, thereby avoiding inadvertent traversal of nuclei, we show here that cytoplasmic irradiation is mutagenic at the CD59 (S1) locus of human-hamster hybrid (AL) cells, while inflicting minimal cytotoxicity. The principal class of mutations induced are similar to those of spontaneous origin and are entirely different from those of nuclear irradiation. Furthermore, experiments with radical scavenger and inhibitor of intracellular glutathione indicated that the mutagenicity of cytoplasmic irradiation depends on generation of reactive oxygen species. These findings suggest that cytoplasm is an important target for genotoxic effects of ionizing radiation, particularly radon, the second leading cause of lung cancer in the United States. In addition, cytoplasmic traversal by alpha particles may be more dangerous than nuclear traversal, because the mutagenicity is accomplished by little or no killing of the target cells.

Wu, Li-Jun; Randers-Pehrson, Gerhard; Xu, An; Waldren, Charles A.; Geard, Charles R.; Yu, Zengliang; Hei, Tom K.

1999-04-01

301

Mitochondrial alteration in malignantly transformed human small airway epithelial cells induced by alpha particles  

PubMed Central

Human small airway epithelial cells (SAECs) immortalized with human telomerase reverse transcriptase (h-TERT) were exposed to either a single or multiple doses of ? particles. Irradiated cells showed a dose-dependent cytotoxicity and progressive neoplastic transformation phenotype. These included an increase in saturation density of growth, a greater resistance to PALA, faster anchorage-independent growth, reinforced cell invasion and c-Myc expression. In addition, the transformed cells formed progressively growing tumors upon inoculation into athymic nude mice. Specifically, ?-irradiation induced damage to both mitochondrial DNA (mtDNA) and mitochondrial functions in transformed cells as evidenced by increased mtDNA copy number and common deletion, decreased oxidative phosphorylation (OXPHOS) activity as measured by cytochrome C oxidase (COX) activity and oxygen consumption. There was a linear correlation between mtDNA copy number, common deletion, COX activity and cellular transformation represented by soft agar colony formation and c-Myc expression. These results suggest that mitochondria are associated with neoplastic transformation of SAEC cells induced by ? particles, and that the oncogenesis process may depend not only on the genomes inside the nucleus, but also on the mitochondrial DNA outside the nucleus.

Zhang, Suping; Wen, Gengyun; Huang, Sarah XL; Wang, Jianrong; Tong, Jian; Hei, Tom K.

2012-01-01

302

Discrete particle detection and metal emissions monitoring using laser-induced breakdown spectroscopy  

SciTech Connect

The unique conditions for the application of laser-induced breakdown spectroscopy (LIBS) as a metal emissions monitoring technology have been discussed. Because of the discrete, particulate nature of effluent metals, the utilization of LIBS is considered in part as a statistical sampling problem involving the finite laser-induced plasma volume, as well as the concentration and size distribution of the target metal species. Particle sampling rates are evaluated and Monte Carlo simulations are presented for relevant LIBS parameters and wastestream conditions. For low metal effluent levels and submicrometer-sized particles, a LIBS-based technique may become sample limited. An approach based on random LIBS sampling and the conditional analysis of the resulting data is proposed as a means to enhance the LIBS sensitivity in actual wastestreams. Monte Carlo simulations and experimental results from a pyrolytic waste processing facility are presented, which demonstrate that a significant enhancement of LIBS performance, greater than an order of magnitude, may be realized by taking advantage of the discrete particulate nature of metals. {copyright} {ital 1997} {ital Society for Applied Spectroscopy}

Hahn, D.W.; Flower, W.L.; Hencken, K.R. [Sandia National Laboratories, Livermore, California94551-0969 (United States)] [Sandia National Laboratories, Livermore, California94551-0969 (United States)

1997-12-01

303

HZE particle radiation induces tissue-specific and p53-dependent mutagenesis in transgenic animals  

NASA Technical Reports Server (NTRS)

Transgenic animals, with the integrated target gene, provide a unique approach for measuring and characterizing mutations in any tissue of the animal. We are using the plasmid-based lacZ transgenic mice with different p53 genetic background to examine radiation-induced genetic damage resulting from exposure to heavy particle radiation. We measured lacZ mutation frequencies (MF) in the brain and spleen tissues at various times after exposing animals to an acute dose of 1 Gy of 1GeV/amu iron particles. MF in the spleen of p53+/+ animals increased up to 2.6-fold above spontaneous levels at 8 weeks post irradiation. In contrast, brain MF from the same animals increased 1.7-fold above controls in the same period. In the p53-/- animals, brain MF increased to 2.2-fold above spontaneous levels at 1 week after treatment, but returned to control levels thereafter. Radiation also induced alterations in the spectrum of mutants in both tissues, accompanied by changes in the frequency of mutants with deletions extending past the transgene into mouse genomic DNA. Our results indicate that the accumulation of transgene MF after radiation exposure is dependant on the tissue examined as well as the p53 genetic background of the animals.

Chang, P. Y.; Kanazawa, N.; Lutze-Mann, L.; Winegar, R.

2001-01-01

304

Asian Dust Particles Induce TGF-?1 via Reactive Oxygen Species in Bronchial Epithelial Cells  

PubMed Central

Background Asian dust storms can be transported across eastern Asia. In vitro, Asian dust particle-induced inflammation and enhancement of the allergic reaction have been observed. However, the fibrotic effects of Asian dust particles are not clear. Production of transforming growth factor ?1 (TGF-?1) and fibronectin were investigated in the bronchial epithelial cells after exposure to Asian dust particulate matter (AD-PM10). Methods During Asian dust storm periods, air samples were collected. The bronchial epithelial cells were exposed to AD-PM10 with and without the antioxidant, N-acetyl-L-cysteine (NAC). Then TGF-?1 and fibronectin were detected by Western blotting. The reactive oxygen species (ROS) was detected by the measurement of dicholorodihydrofluorescin (DCF), using a FACScan, and visualized by a confocal microscopy. Results The expression of TGF-?1, fibronectin and ROS was high after being exposed to AD-PM10, compared to the control. NAC attenuated both TGF-?1 and fibronectin expression in the AD-PM10-exposed the bronchial epithelial cells. Conclusion AD-PM10 may have fibrotic potential in the bronchial epithelial cells and the possible mechanism is AD-PM10-induced intracellular ROS.

Kyung, Sun Young; Yoon, Jin Young; Kim, Yu Jin; Lee, Sang Pyo; Park, Jeong-Woong

2012-01-01

305

A theoretical study of induced-charge dipolophoresis of ideally polarizable asymmetrically slipping Janus particles  

NASA Astrophysics Data System (ADS)

We consider the non linear electrophoretic transport of uncharged, ideally polarizable hydrodynamic Janus spheres, the inhomogeneity of which is produced by a variable Navier slip condition at the particle surface. A general, three dimensional formulation enabling calculation of the electrophoretic mobility of any patchy particle, with an arbitrary tensorial slip boundary condition is provided. The solution avoids the common assumption of an infinitely thin electric double layer (?) and Navier slip coefficient (b) and is thereby valid for finite values of these parameters, which is of particular importance at the nanoscale. The specific case of a Janus sphere, consisting of two equal hemispheres, each with a different but constant slip boundary condition is solved semi-analytically and numerically. In the instance where the slip coefficients at each hemisphere are equal, induced charge electro-osmotic flow is evident at an increased rate as compared to a homogeneous sphere with no slip. If the slip coefficients differ from each other, the particle is found to self-align with the electric field and travel with the slip surface facing forward. The increased pumping rates and mobility found in the cases of the homogeneous and Janus spheres respectively, occur as a function of the ratio b/b?? and are most significant for the combination of a thin electric double layer (EDL) and large slip length. However, it is also illustrated that the size of the EDL independently dominates the effects of slip.

Boymelgreen, Alicia M.; Miloh, Touvia

2011-07-01

306

Preparation of submicron-sized gold particles using laser-induced agglomeration-fusion process  

NASA Astrophysics Data System (ADS)

Recently, laser irradiation (LI) of colloidal nanoparticles (NPs) using a non-focused laser beam at moderate fluence attracts much attention as a novel and simple technique to obtain submicron-sized spherical particles. In the present study, we applied this technique to prepare gold SMPs. It was revealed that agglomeration of the source nanoparticles prior to laser irradiation is necessary to produce SMPs. However, when the agglomeration occurred in too much extent, significant amount of the source particles remained as the sediment after LI, leading to the lowering of the formation efficiency of SMPs. Therefore, the control of the agglomeration conditions of the source NPs is necessary to obtain SMPs efficiently. In the present study, we tried to adjust the agglomeration conditions of the source NPs by adjusting the concentration of citrate that was used as the stabilizing reagent of the source NPs. It was revealed that SMPs were obtained efficiently while the sedimentation of the source NPs were suppressed when the concentration of citrate was adjusted around 0.01-0.005 mM. In addition, observation of the temporal change in the shape of the colloidal particles during LI revealed that there is an induction period in which no formation of SMPs is brought about by LI. This finding suggested that LI removes the citrate ligands from the source NPs and induces the agglomeration of the source NPs, i.e. the agglomeration condition of the source NPs is also controlled by LI.

Tsuji, T.; Higashi, Y.; Tsuji, M.; Ishikawa, Y.; Koshizaki, N.

2014-03-01

307

Flow-induced translocation of polymers through a fluidic channel: A dissipative particle dynamics simulation study  

NASA Astrophysics Data System (ADS)

The dynamics of flow-induced translocation of polymers through a fluidic channel has been studied by dissipative particle dynamics (DPD) approach. Unlike implicit solvent models, the many-body energetic and hydrodynamic interactions are preserved naturally by incorporating explicit solvent particles in this approach. The no-slip wall boundary and the adaptive boundary conditions have been implemented in the modified DPD approach to model the hydrodynamic flow within a specific wall structure of fluidic channel and control the particles' density fluctuations. The results show that the average translocation time versus polymer chain length satisfies a power-law scaling of ? ~N1.152. The conformational changes and translocation dynamics of polymers through the fluidic channel have also been investigated in our simulations, and two different translocation processes, i.e., the single-file and double-folded translocation events, have been observed in detail. These findings may be helpful in understanding the conformational and dynamic behaviors of such polymer and/or DNA molecules during the translocation processes.

Guo, Jiayi; Li, Xuejin; Liu, Yuan; Liang, Haojun

2011-04-01

308

The effect of flow geometry on shear-induced particle segregation and resuspension  

NASA Astrophysics Data System (ADS)

In this thesis, we investigate through theory and experiment the influence of the flow geometry on various shear-induced migration phenomena such as particle demixing, viscous resuspension and meniscus accumulation for a suspension of rigid, non-colloidal particles. The major focus of this thesis is the elucidation of a particle flux mechanism that has been ignored in the literature in the theoretical calculation of the concentration distribution in shear-induced migration phenomena. This mechanism is the convective flux due to the secondary currents arising from the non-Newtonian rheology of suspensions. Historically, suspensions have been modeled as Newtonian fluids with concentration dependent viscosities when calculating velocity distributions due to the tremendous simplification of the governing equations. The results presented in this thesis, however, demonstrate that it is critical to consider the complete rheology of a concentrated suspension when modeling flows in complex geometries. While the magnitude of the secondary currents is small, in many cases they are the dominant mechanism governing the resulting particle concentration distribution. In chapters 2 through 4, we investigate the impact of these secondary currents on the concentration profiles developed in suspension flow through conduits of arbitrary geometry, and in resuspension flow through a tube. In chapter 5, we examine the radial segregation of particles in the squeeze flow of concentrated suspensions. This flow is identical to that produced in loading suspensions on to a parallel plate viscometer and thus the concentration inhomogeneities generated during the loading phenomenon may play a role in the well known scatter of torque measurements in this system. We develop a criterion in terms of the experimental parameters in a parallel plate experiment for the onset of radial inhomogeneities. In the final investigation reported in this thesis, we develop a theoretical model for describing the droplet distribution in the Poiseuille flow of an emulsion through a tube. We show that the mathematical problem that results from this model is amenable to self-similar analysis via the trial function approach. The self-similar solution so obtained is used to evaluate oscillatory flows as a possible technique for separation of the dispersed phase from suspending fluid.

Ramachandran, Arun

309

Baseline triglyceride levels and insulin sensitivity are major determinants of the increase of LDL particle size and buoyancy induced by rosuvastatin treatment in patients with primary hyperlipidemia.  

PubMed

The influence of various statins on low-density-lipoprotein (LDL)-particle phenotype has been reportedly trivial or moderate. We assessed the effect of rosuvastatin (the newest statin available) on the LDL subfraction profile in patients with primary hyperlipidemia. One hundred and twenty patients with primary hyperlipidemia without evidence of cardiovascular disease were randomized to therapeutic lifestyle modification ('control' group, N=60) or therapeutic lifestyle modification plus rosuvastatin 20 mg/day (N=60). Laboratory evaluation was performed at baseline and 12 weeks post-treatment. LDL subfraction analysis was carried out electrophoretically using of high-resolution 3% polyacrylamide gel tubes and the Lipoprint LDL System. Rosuvastatin induced a redistribution of LDL-cholesterol from small-dense LDL particles to large-buoyant ones and increased the mean LDL particle size. This beneficial effect was observed only in patients with baseline triglyceride levels >or=150 mg/dl (mean LDL particle size 255+/-7 A vs 260+/-5 A, P<0.01), whereas the LDL subfraction profile was not altered in those with triglyceride levels <150 mg/dl. Stepwise multivariate linear regression analysis revealed that baseline triglyceride levels (R(2)=0.29, P=0.001) followed by baseline insulin resistance as assessed by the HOmeostasis Model Assessment (HOMA) (R(2)=0.25, P=0.001) were independently associated with the rosuvastatin-induced increase in the mean LDL particle size. In conclusion, rosuvastatin at 20 mg/day favorably modified the relative distribution of LDL-cholesterol distribution on LDL subfractions as well as on the mean LDL particle size in patients treated for primary dyslipidemia. Baseline triglyceride levels as well as baseline HOMA-index were found to be the major predictors of this beneficial action of rosuvastatin. PMID:18585701

Kostapanos, Michael S; Milionis, Haralampos J; Lagos, Konstantinos G; Rizos, Christos B; Tselepis, Alexandros D; Elisaf, Moses S

2008-08-20

310

Drug-induced graves disease from CTLA-4 receptor suppression.  

PubMed

Monoclonal antibody, ipilimumab, useful for treatment of metastatic melanoma, blocks CTLA-4 mediated T-cell suppression and can also cause a Graves ophthalmopathy like syndrome. Epidemiologic study has linked variant polymorphisms of CTLA-4 receptor gene to the presence of thyroid eye disease. The combination of these observations suggests CTLA-4 mediated T-cell functions are important to the pathogenesis of thyroid-associated eye disease. PMID:21242854

Borodic, Gary; Hinkle, David M; Cia, Yihong

2011-01-01

311

Protective Effect of Vaccines on Mycoplasma pulmonis-Induced Respiratory Disease of Mice  

PubMed Central

Mice inoculated intranasally with either a virulent or an avirulent strain of live Mycoplasma pulmonis were resistant to respiratory disease induced by a subsequent intranasal challenge with virulent organisms. Similarly, mice inoculated intravenously with the virulent strain were resistant to intranasal challenge with the same strain. In contrast, mice inoculated intravenously with avirulent M. pulmonis were not resistant to intranasal challenge with the virulent mycoplasma strain. Studies on mice inoculated intravenously with the two strains of M. pulmonis indicated that persistance of mycoplasmas in the respiratory tract may be important in inducing resistance to intranasal challenge with M. pulmonis. These observations, together with the lack of correlation between the level of serum antibodies and resistance to M. pulmonis-induced respiratory disease, suggested that local immune mechanisms were important in resistance. It is proposed that an effective vaccination schedule to protect mice against M. pulmonis-induced respiratory disease may be one that stimulates both systemic and local immune defenses. This suggestion is supported by the observation that systemic followed by local administration of inactivated M. pulmonis was more effective in inducing resistance in mice to intranasal challenge with live organisms than was systemic administration alone. In addition, mice inoculated solely by the intranasal route with inactivated mycoplasmas were resistant to M. pulmonis-induced respiratory disease. These studies indicate the importance of local defense mechanisms in the induction of resistance to M. pulmonis-induced respiratory disease in mice.

Taylor, Geraldine; Howard, C. J.; Gourlay, R. N.

1977-01-01

312

Parkinson's disease induced pluripotent stem cells with triplication of the ?-synuclein locus  

PubMed Central

A major barrier to research on Parkinson's disease is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells from patients and differentiate them into neurons affected by disease. Triplication of SNCA, encoding ?-synuclein, causes a fully penetrant, aggressive form of Parkinson's disease with dementia. ?-Synuclein dysfunction is the critical pathogenic event in Parkinson's disease, multiple system atrophy and dementia with Lewy bodies. Here we produce multiple induced pluripotent stem cell lines from an SNCA triplication patient and an unaffected first-degree relative. When these cells are differentiated into midbrain dopaminergic neurons, those from the patient produce double the amount of ?-synuclein protein as neurons from the unaffected relative, precisely recapitulating the cause of Parkinson's disease in these individuals. This model represents a new experimental system to identify compounds that reduce levels of ?-synuclein, and to investigate the mechanistic basis of neurodegeneration caused by ?-synuclein dysfunction.

Devine, Michael J.; Ryten, Mina; Vodicka, Petr; Thomson, Alison J.; Burdon, Tom; Houlden, Henry; Cavaleri, Fatima; Nagano, Masumi; Drummond, Nicola J.; Taanman, Jan-Willem; Schapira, Anthony H.; Gwinn, Katrina; Hardy, John; Lewis, Patrick A.; Kunath, Tilo

2011-01-01

313

Naturally Occurring Adenovirus-Induced Respiratory Disease in Two Guinea Pigs.  

National Technical Information Service (NTIS)

Respiratory disease is a common cause of morbidity in the guinea pig, and is chiefly of bacterial origin (5). Although a variety of viral diseases do occur in the guinea pig, there has been only one previous report of an adenovirus-induced respiratory dis...

L. H. Brennecke T. M. Dreier W. S. Stokes

1982-01-01

314

Lack of effect of inhaled morphine on exercise-induced breathlessness in chronic obstructive pulmonary disease  

Microsoft Academic Search

BACKGROUND--Inhaled nebulised morphine may reduce breathlessness in patients with lung disease, although the results of controlled trials are conflicting. A direct action of morphine on the lung has been postulated. This study aimed to investigate whether nebulised morphine reduced exercise-induced breathlessness in patients with chronic obstructive pulmonary disease (COPD) and to determine if this was a local pulmonary effect or

A R Masood; J W Reed; S H Thomas

1995-01-01

315

Interaction of the human cytomegalovirus particle with the host cell induces hypoxia-inducible factor 1 alpha  

SciTech Connect

The cellular protein hypoxia-inducible factor 1 alpha (HIF-1{alpha}) was induced after infection of human fibroblasts with human cytomegalovirus (HCMV). HCMV irradiated with ultraviolet light (uv-HCMV) also elicited the effect, demonstrating that the response was provoked by interaction of the infecting virion with the cell and that viral gene expression was not required. Although induction of HIF-1{alpha} was initiated by an early event, accumulation of the protein was not detected until 9 hours post infection, with levels increasing thereafter. Infection with uv-HCMV resulted in increased abundance of HIF-1{alpha}-specific RNA, indicating stimulation of transcription. In addition, greater phosphorylation of the protein kinase Akt was observed, and the activity of this enzyme was required for induction of HIF-1{alpha} to occur. HIF-1{alpha} controls the expression of many cellular gene products; therefore the findings reveal new ways in which interaction of the HCMV particle with the host cell may cause significant alterations to cellular physiology.

McFarlane, Steven; Nicholl, Mary Jane; Sutherland, Jane S.; Preston, Chris M., E-mail: Christopher.preston@glasgow.ac.u

2011-05-25

316

Role of Mutagenicity in Asbestos Fiber-Induced Carcinogenicity and Other Diseases  

Microsoft Academic Search

The cellular and molecular mechanisms of how asbestos fibers induce cancers and other diseases are not well understood. Both serpentine and amphibole asbestos fibers have been shown to induce oxidative stress, inflammatory responses, cellular toxicity and tissue injuries, genetic changes, and epigenetic alterations in target cells in vitro and tissues in vivo. Most of these mechanisms are believe to be

Sarah X. L. Huang; Marie-Claude Jaurand; David W. Kamp; John Whysner; Tom K. Hei

2011-01-01

317

Induced pluripotent stem cells for retinal degenerative diseases: a new perspective on the challenges  

Microsoft Academic Search

Retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, are the prodominant causes\\u000a of human blindness in the world; however, these diseases are difficult to treat. Currently, knowledge on the mechanisms of\\u000a these diseases is still very limited and no radical drugs are available. Induced pluripotent stem (iPS) cells are an innovative\\u000a technology that turns somatic cells into embryonic

Zi-Bing Jin; Satoshi Okamoto; Michiko Mandai; Masayo Takahashi

2009-01-01

318

Gluten induces an intestinal cytokine response strongly dominated by interferon gamma in patients with celiac disease  

Microsoft Academic Search

Background & Aims: Celiac disease appears to be a T cell–mediated enteropathy induced by gluten in genetically predisposed individuals. Duodenal biopsy specimens from patients with celiac disease and histologically normal controls were investigated to see if cytokine expression is related to disease activity. Methods: Cytokine messenger RNA (mRNA) expression was determined by quantitative reverse-transcription polymerase chain reaction and in situ

Ellen M. Nilsen; Frode L. Jahnsen; Knut E. A. Lundin; Olav Fausa; Ludvig M. Sollid; Jørgen Jahnsen; Helge Scott; Per Brandtzaeg

1998-01-01

319

The mechanism of human plasma phospholipid transfer protein-induced enlargement of high-density lipoprotein particles: evidence for particle fusion.  

PubMed Central

1. Phospholipid transfer protein (PLTP) mediates conversion of high-density lipoprotein (HDL3) to large particles, with concomitant release of apolipoprotein A-I (apoA-I). To study the mechanisms involved in this conversion, reconstituted HDL (rHDL) particles containing either fluorescent pyrenylacyl cholesterol ester (PyrCE) in their core (PyrCE-rHDL) or pyrenylacyl phosphatidylcholine (PysPC) in their surface lipid layer (PyrPC-rHDL) were prepared. Upon incubation with PLTP they behaved as native HDL3, in that their size increased considerably. 2. When PyrPC-rHDL was incubated with HDL3 in the presence of PLTP, a rapid decline of the pyrene excimer/monomer fluorescence ratio (E/M) occurred, demonstrating that PLTP induced mixing of the surface lipids of PyrPC-rHDL and HDL3. As this mixing was almost complete before any significant increase in HDL particle size was observed, it represents PLTP-mediated phospholipid transfer or exchange that is not directly coupled to the formation of large HDL particles. 3. When core-labelled PyrCE-rHDL was incubated in the presence of PLTP, a much slower, time-dependent decrease of E/M was observed, demonstrating that PLTP also promotes mixing of the core lipids. The rate and extent of mixing of core lipids correlated with the amount of PLTP added and with the increase in particle size. The enlarged particles formed could be visualized as discrete, non-aggregated particles by electron microscopy. Concomitantly with the appearance of enlarged particles, lipid-poor apoA-I molecules were released. These data, together with the fact that PLTP has been shown not to mediate transfer of cholesterol esters, strongly suggest that particle fusion rather than (net) lipid transfer or particle aggregation is responsible for the enlargement of HDL particles observed upon incubation with PLTP.4.ApoA-I rHDL, but not apoA-II rHDL, were converted into large particles, suggesting that the presence of apoA-I is required for PLTP-mediated HDL fusion. A model for PLTP-mediated enlargement of HDL particles is presented.

Lusa, S; Jauhiainen, M; Metso, J; Somerharju, P; Ehnholm, C

1996-01-01

320

In situ pulmonary localization of air pollution particle-induced oxidative stress.  

PubMed

Exposure to air particulate matter (PM) may be associated with increased morbidity and mortality. An improved understanding of the mechanism(s) by which PM induces adverse effects is needed. This preliminary study examined the ability to use unique bioluminescent technologies to identify acute localized areas of residual oil fly ash (ROFA)-induced, oxidative lung injury. Transgenic mice, in which luciferase (luc) expression was regulated by the heme oxygenase (HO)-1 promoter, were exposed by pharyngeal aspiration to either saline or 50 microg ROFA/mouse. HO-1-luc expression was determined at 2, 6, 12, and 24 h postexposure using luminescent quantification and Western blot analysis of lung protein extracts, as well as with a novel in situ pulmonary bioluminescence imaging approach. The different approaches for the detection of luciferase in lung protein extracts recovered from ROFA exposed HO-1-luc transgenic mice gave variable results. Pulmonary homogenate HO-1-luc levels were increased at 2 h and 24 h postexposure to ROFA when examined by chemilumescent and Western blot analyses, respectively. In situ bioluminescent imaging of pulmonary tissue sections detected ROFA-induced pulmonary luciferase expression by identifying highly localized increases in HO-1-luc expression at 12 h and 24 h postexposure. These results suggest that the variability observed in the methods of detection for luciferase may be due to a localization of cells expressing luciferase within tissue samples, demonstrating that the HO-1-luc transgenic mouse model is the preferred method to detect and pinpoint in vivo particle-induced, oxidative lung injury. The feasibility of using this in situ approach is a unique proof-of-concept application for the identification of localized sites of oxidative injury induced by environmental pollutants. PMID:17966064

Roberts, Elizabeth S; Malstrom, Scott E; Dreher, Kevin L

2007-11-01

321

Epstein-Barr virus induced hemophagocytic lymphohistiocytosis in X-linked lymphoproliferative disease  

PubMed Central

X-linked lymphoproliferative disease (XLP) is a rare, often fatal genetic disorder characterized by extreme vulnerability to Epstein-Barr virus (EBV). EBV-induced hemophagocytic lymphohistiocytosis (HLH) is a known presentation in XLP. In EBV-induced HLH in XLP, the brain imaging findings in the acute phase include a non specific pattern. In this report, we highlight the magnetic resonance imaging and magnetic resonance spectroscopy findings in a child with EBV induced HLH in XLP.

Sankararaman, Senthilkumar; Riel-Romero, Rosario Maria; Jeroudi, Majed; Gonzalez-Toledo, Eduardo

2014-01-01

322

Thiopurine-Induced Myelotoxicity in Patients With Inflammatory Bowel Disease: A Review  

Microsoft Academic Search

AIM:Probably, the most important and potentially lethal adverse event of azathioprine (AZA) and mercaptopurine (MP) is myelosuppression. Our aim was to conduct a review of AZA\\/MP-induced myelotoxicity in inflammatory bowel disease (IBD) patients.METHODS:Bibliographical searches were performed in MEDLINE\\/EMBASE. The studies evaluating thiopurine-induced myelotoxicity in patients with IBD were reviewed. The cumulative incidence and the incidence rate of AZA\\/MP-induced myelotoxicity were

Javier P. Gisbert; Fernando Gomollón

2008-01-01

323

The severity of alpha-particle-induced DNA damage is revealed by exposure to cell-free extracts  

SciTech Connect

The rejoining of single-strand breaks induced by {alpha}-particle and {gamma} irradiation in plasmid DNA under two scavenging conditions has been compared. At the two scavenger conditions has been compared. At the two scavenger capacities used of 1.5 {times} 10{sup 7} and 3 {times} 10{sup 8}s{sup {minus}1} using Tris-HCl as the scavenger, the ratio of single- to double-strand breaks for {alpha} particles is fivefold less than the corresponding ratios for {gamma} irradiation. The repair of such radiation-induced single-strand breaks has been examined using a cell-free system derived from human whole-cell extracts. We show that the rejoining of single-strand breaks for both {alpha}-particle- and {gamma}-irradiated plasmid is dependent upon the scavenging capacity and that the efficiency of rejoining of {alpha}-particle-induced single-strand breaks is significantly less than that observed for {gamma}-ray-induced breaks. In addition, for DNA that had been irradiated under conditions that mimic the cellular environment with respect to the radical scavenging capacity, 50 of {alpha}-particle-induced single-strand breaks are converted to double-strand breaks, in contrast with only {approximately}12% conversion of {gamma}-ray-induced single-strand breaks, indicating that the initial damage caused by {alpha} particles is more severe. These studies provide experimental evidence for increased clustering of damage which may have important implications for the induction of cancer by low-level {alpha}-particle sources such as domestic radon. 37 refs., 5 figs., 1 tab.

Hodgkins, P.S.; O`Neill, P.; Stevens, D.; Fairman, M.P. [Medical Research Council, Oxfordshire (United Kingdom)

1996-12-01

324

Labetalol-induced Peyronie's disease? A case report.  

PubMed

Peyronie's disease (induratio penis plastica) has been observed in a 58-year-old man 8 months after initiation of treatment with the new combined alpha- and beta-blocking agent, labetalol. During the last 2 months before onset of symptoms he had received 2400 mg labetalol daily. He showed no other signs of abnormal fibrous tissue production and the ANF test was negative. Cessation of the drug revealed no improvement. Peyronie's disease has also been observed in relation to treatment with propranolol, practolol and metoprolol and might be due to an impaired balance between alpha- and beta-receptors in connective tissue, but there may also be an immunological basis for the fibrosis. A possible coincidence is stressed, as the ages of the reported cases are within the range where this disease most often develops. PMID:231377

Kristensen, B O

1979-01-01

325

Macromolecular prodrug of dexamethasone prevents particle-induced peri-implant osteolysis with reduced systemic side effects.  

PubMed

Aseptic implant loosening related to implant wear particle-induced inflammation is the most common cause of failure after joint replacement. Modulation of the inflammatory reaction to the wear products represents a rational approach for preventing aseptic implant failure. Long-term treatment using anti-inflammatory agents, however, can be associated with significant systemic side effects due to the drugs' lack of tissue specificity. To address this issue, N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-dexamethasone conjugate (P-Dex) was developed and evaluated for prevention of wear particle-induced osteolysis and the loss of fixation in a murine prosthesis failure model. Daily administration of free dexamethasone (Dex) was able to prevent wear particle-induced osteolysis, as assessed by micro-CT and histological analysis. Remarkably, monthly P-Dex administration (dose equivalent to free Dex treatment) was equally effective as free dexamethasone, but was not associated with systemic bone loss (a major adverse side effect of glucocorticoids). The reduced systemic toxicity of P-Dex is related to preferential targeting of the sites of wear particle-induced inflammation and its subcellular sequestration and retention by local inflammatory cell populations, resulting in sustained therapeutic action. These results demonstrate the feasibility of utilizing a macromolecular prodrug with reduced systemic toxicity to prevent wear particle-induced osteolysis. PMID:24326124

Ren, Ke; Dusad, Anand; Yuan, Fang; Yuan, Hongjiang; Purdue, P Edward; Fehringer, Edward V; Garvin, Kevin L; Goldring, Steven R; Wang, Dong

2014-02-10

326

Drug-Induced Pulmonary Vascular Disease--Mechanisms and Clinical Patterns  

PubMed Central

An extensive vascular surface area places the lungs at risk for damage by blood-borne drugs. Drug-induced pulmonary vascular disease may present clinically as acute pulmonary edema, pulmonary edema followed by diffuse interstitial lung disease, pulmonary vascular occlusion, pulmonary hypertension or hemorrhage. It is important to recognize these reactions as drug-related because many are reversible with discontinuation of the drug and supportive therapy. Failure to recognize drug-induced pulmonary vascular disease can lead to significant morbidity and, in some cases, death. ImagesFigure 1.Figure 2.Figure 2.Figure 3.

Kumar, Kusum; Holden, William E.

1986-01-01

327

Inducible Expression of Transmembrane Proteins on Bacterial Magnetic Particles in Magnetospirillum magneticum AMB-1?  

PubMed Central

Bacterial magnetic particles (BacMPs) produced by the magnetotactic bacterium Magnetospirillum magneticum AMB-1 are used for a variety of biomedical applications. In particular, the lipid bilayer surrounding BacMPs has been reported to be amenable to the insertion of recombinant transmembrane proteins; however, the display of transmembrane proteins in BacMP membranes remains a technical challenge due to the cytotoxic effects of the proteins when they are overexpressed in bacterial cells. In this study, a tetracycline-inducible expression system was developed to display transmembrane proteins on BacMPs. The expression and localization of the target proteins were confirmed using luciferase and green fluorescent protein as reporter proteins. Gene expression was suppressed in the absence of anhydrotetracycline, and the level of protein expression could be controlled by modulating the concentration of the inducer molecule. This system was implemented to obtain the expression of the tetraspanin CD81. The truncated form of CD81 including the ligand binding site was successfully displayed at the surface of BacMPs by using Mms13 as an anchor protein and was shown to bind the hepatitis C virus envelope protein E2. These results suggest that the tetracycline-inducible expression system described here will be a useful tool for the expression and display of transmembrane proteins in the membranes of BacMPs.

Yoshino, Tomoko; Shimojo, Akiko; Maeda, Yoshiaki; Matsunaga, Tadashi

2010-01-01

328

Inducible expression of transmembrane proteins on bacterial magnetic particles in Magnetospirillum magneticum AMB-1.  

PubMed

Bacterial magnetic particles (BacMPs) produced by the magnetotactic bacterium Magnetospirillum magneticum AMB-1 are used for a variety of biomedical applications. In particular, the lipid bilayer surrounding BacMPs has been reported to be amenable to the insertion of recombinant transmembrane proteins; however, the display of transmembrane proteins in BacMP membranes remains a technical challenge due to the cytotoxic effects of the proteins when they are overexpressed in bacterial cells. In this study, a tetracycline-inducible expression system was developed to display transmembrane proteins on BacMPs. The expression and localization of the target proteins were confirmed using luciferase and green fluorescent protein as reporter proteins. Gene expression was suppressed in the absence of anhydrotetracycline, and the level of protein expression could be controlled by modulating the concentration of the inducer molecule. This system was implemented to obtain the expression of the tetraspanin CD81. The truncated form of CD81 including the ligand binding site was successfully displayed at the surface of BacMPs by using Mms13 as an anchor protein and was shown to bind the hepatitis C virus envelope protein E2. These results suggest that the tetracycline-inducible expression system described here will be a useful tool for the expression and display of transmembrane proteins in the membranes of BacMPs. PMID:20038711

Yoshino, Tomoko; Shimojo, Akiko; Maeda, Yoshiaki; Matsunaga, Tadashi

2010-02-01

329

FE2O3 PARTICLE-INDUCED PROSTAGLANDIN E2 (PGE2) SYNTHESIS IN ALVEOLAR MACROPHAGES (AM) DETERMINES PARTICULATE INFLAMMATORY POTENTIAL  

EPA Science Inventory

As shown by epidemiologic studies, acute exposure to ambient particles is associated with exacerbation of pulmonary and cardiovascular diseases. Metals associated with particles are able to mediate lung injury via oxidant-catalyzed reactions. However, the underlying mechanism i...

330

Foot-and-mouth disease virus particles inactivated with binary ethylenimine are efficiently internalized into cultured cells.  

PubMed

Conventional foot-and-mouth disease (FMD) vaccines are produced from virus grown in cell culture that is chemically inactivated by using binary ethylenimide (BEI). Here, we show that BEI treatment preserves both the architecture of FMDV particles, as inactivated viral particles showed by electron microscopy characteristics similar to those of infectious virions, as well as the general features of infectious virus internalization. Binding of inactivated particles to BHK-21 cells was blocked by preincubation with either a FMDV-specific monoclonal antibody or a synthetic peptide spanning the integrin-binding viral motif Arg-Gly-Asp (RGD). In addition, these particles were internalized into cultured cells through endocytosis, being directed to early endosomes, as indicated by their colocalization with the marker protein Rab5. When purified BEI-inactivated virions were labelled and their interaction with live cultured cells analyzed by time-lapse fluorescence microscopy, a major subpopulation of virus particles, about 80%, was shown to undergo internalization into a static endosome population, insensitive to the microtubule depolymerization exerted by nocodazole, while the remaining subpopulation (about 20%) was dynamic and sensitive to this drug. Thus, BEI-inactivated particles provide an interesting tool to study early steps in FMDV-cell interactions enabling a distinction between FMDV internalization and productive infection. Possible implications for FMDV immune response elicited following vaccine administration are discussed. PMID:22027488

Martín-Acebes, Miguel A; Vázquez-Calvo, Angela; González-Magaldi, Mónica; Sobrino, Francisco

2011-12-01

331

Dopamine-Induced Nonmotor Symptoms of Parkinson's Disease  

PubMed Central

Nonmotor symptoms of Parkinson's disease (PD) may emerge secondary to the underlying pathogenesis of the disease, while others are recognized side effects of treatment. Inevitably, there is an overlap as the disease advances and patients require higher dosages and more complex medical regimens. The non-motor symptoms that emerge secondary to dopaminergic therapy encompass several domains, including neuropsychiatric, autonomic, and sleep. These are detailed in the paper. Neuropsychiatric complications include hallucinations and psychosis. In addition, compulsive behaviors, such as pathological gambling, hypersexuality, shopping, binge eating, and punding, have been shown to have a clear association with dopaminergic medications. Dopamine dysregulation syndrome (DDS) is a compulsive behavior that is typically viewed through the lens of addiction, with patients needing escalating dosages of dopamine replacement therapy. Treatment side effects on the autonomic system include nausea, orthostatic hypotension, and constipation. Sleep disturbances include fragmented sleep, nighttime sleep problems, daytime sleepiness, and sleep attacks. Recognizing the non-motor symptoms that can arise specifically from dopamine therapy is useful to help optimize treatment regimens for this complex disease.

Park, Ariane; Stacy, Mark

2011-01-01

332

Exercise-induced myokines and their role in chronic diseases.  

PubMed

Physical inactivity has recently been identified as a major and independent risk factor for the development of dementia and cognitive decline. In addition to the effect of exercise with regard to protection against neurodegenerative diseases, it is well-established that physical inactivity increases the risk of type 2 diabetes, cardiovascular diseases (CVD), colon cancer and postmenopausal breast cancer. These diseases constitute a network of related diseases, also called "the diseasome of physical inactivity". In this review, physical inactivity is given the central role as an independent and strong risk factor for accumulation of visceral fat and consequently the activation of a network of systemic inflammatory pathways, which promote development of neurodegeneration as well as insulin resistance, atherosclerosis, and tumour growth. The recent finding that muscles produce and release myokines provides a conceptual basis for understanding some of the molecular mechanisms underlying organ cross talk, including muscle-fat cross talk. Accumulating data suggest that contracting skeletal muscles release myokines, which may work in a hormone-like fashion, exerting specific endocrine effects on visceral fat or mediating direct anti-inflammatory effects. Other myokines work locally within the muscle via paracrine mechanisms, exerting their effects on signalling pathways involved in fat oxidation. PMID:21354469

Pedersen, Bente K

2011-07-01

333

Dieldrin-induced neurotoxicity: relevance to Parkinson's disease pathogenesis.  

PubMed

Parkinson's disease (PD) is increasingly recognized as a neurodegenerative disorder strongly associated with environmental chemical exposures. Recent epidemiological data demonstrate that environmental risk factors may play a dominant role as compared to genetic factors in the etiopathogenesis of idiopathic Parkinson's disease. Identification of key genetic defects such as alpha-synuclein and parkin mutations in PD also underscores the important role of genetic factors in the disease. Thus, understanding the interplay between genes and environment in PD may be critical to unlocking the mysteries of this 200-year-old neurodegenerative disease. Pesticides and metals are the most common classes of environmental chemicals that promote dopaminergic degeneration. The organochlorine pesticide dieldrin has been found in human PD postmortem brain tissues, suggesting that this pesticide has potential to promote nigral cell death. Though dieldrin has been banned, humans continue to be exposed to the pesticide through contaminated dairy products and meats due to the persistent accumulation of the pesticide in the environment. This review summarizes various neurotoxic studies conducted in both cell culture and animals models following dieldrin exposure and discusses their relevance to key pathological mechanisms associated with nigral dopaminergic degeneration including oxidative stress, mitochondrial dysfunction, protein aggregation, and apoptosis. PMID:16112328

Kanthasamy, Anumantha G; Kitazawa, Masashi; Kanthasamy, Arthi; Anantharam, Vellareddy

2005-08-01

334

Anacardic acids from cashew nuts ameliorate lung damage induced by exposure to diesel exhaust particles in mice.  

PubMed

Anacardic acids from cashew nut shell liquid, a Brazilian natural substance, have antimicrobial and antioxidant activities and modulate immune responses and angiogenesis. As inflammatory lung diseases have been correlated to environmental pollutants exposure and no reports addressing the effects of dietary supplementation with anacardic acids on lung inflammation in vivo have been evidenced, we investigated the effects of supplementation with anacardic acids in a model of diesel exhaust particle- (DEP-) induced lung inflammation. BALB/c mice received an intranasal instillation of 50? ? g of DEP for 20 days. Ten days prior to DEP instillation, animals were pretreated orally with 50, 150, or 250?mg/kg of anacardic acids or vehicle (100? ? L of cashew nut oil) for 30 days. The biomarkers of inflammatory and antioxidant responses in the alveolar parenchyma, bronchoalveolar lavage fluid (BALF), and pulmonary vessels were investigated. All doses of anacardic acids ameliorated antioxidant enzyme activities and decreased vascular adhesion molecule in vessels. Animals that received 50?mg/kg of anacardic acids showed decreased levels of neutrophils and tumor necrosis factor in the lungs and BALF, respectively. In summary, we demonstrated that AAs supplementation has a potential protective role on oxidative and inflammatory mechanisms in the lungs. PMID:23533495

Carvalho, Ana Laura Nicoletti; Annoni, Raquel; Torres, Larissa Helena Lobo; Durão, Ana Carolina Cardoso Santos; Shimada, Ana Lucia Borges; Almeida, Francine Maria; Hebeda, Cristina Bichels; Lopes, Fernanda Degobbi Tenorio Quirino Santos; Dolhnikoff, Marisa; Martins, Milton Arruda; Silva, Luiz Fernando Ferraz; Farsky, Sandra Helena Poliselli; Saldiva, Paulo Hilário Nascimento; Ulrich, Cornelia M; Owen, Robert W; Marcourakis, Tania; Trevisan, Maria Teresa Salles; Mauad, Thais

2013-01-01

335

Anacardic Acids from Cashew Nuts Ameliorate Lung Damage Induced by Exposure to Diesel Exhaust Particles in Mice  

PubMed Central

Anacardic acids from cashew nut shell liquid, a Brazilian natural substance, have antimicrobial and antioxidant activities and modulate immune responses and angiogenesis. As inflammatory lung diseases have been correlated to environmental pollutants exposure and no reports addressing the effects of dietary supplementation with anacardic acids on lung inflammation in vivo have been evidenced, we investigated the effects of supplementation with anacardic acids in a model of diesel exhaust particle- (DEP-) induced lung inflammation. BALB/c mice received an intranasal instillation of 50??g of DEP for 20 days. Ten days prior to DEP instillation, animals were pretreated orally with 50, 150, or 250?mg/kg of anacardic acids or vehicle (100??L of cashew nut oil) for 30 days. The biomarkers of inflammatory and antioxidant responses in the alveolar parenchyma, bronchoalveolar lavage fluid (BALF), and pulmonary vessels were investigated. All doses of anacardic acids ameliorated antioxidant enzyme activities and decreased vascular adhesion molecule in vessels. Animals that received 50?mg/kg of anacardic acids showed decreased levels of neutrophils and tumor necrosis factor in the lungs and BALF, respectively. In summary, we demonstrated that AAs supplementation has a potential protective role on oxidative and inflammatory mechanisms in the lungs.

Carvalho, Ana Laura Nicoletti; Annoni, Raquel; Torres, Larissa Helena Lobo; Durao, Ana Carolina Cardoso Santos; Shimada, Ana Lucia Borges; Almeida, Francine Maria; Hebeda, Cristina Bichels; Lopes, Fernanda Degobbi Tenorio Quirino Santos; Dolhnikoff, Marisa; Martins, Milton Arruda; Silva, Luiz Fernando Ferraz; Farsky, Sandra Helena Poliselli; Saldiva, Paulo Hilario Nascimento; Ulrich, Cornelia M.; Owen, Robert W.; Marcourakis, Tania; Trevisan, Maria Teresa Salles; Mauad, Thais

2013-01-01

336

Motility-Induced Phase Separation in Active Matter: a generic formalism for active brownian particles and run-and-tumble particles  

NASA Astrophysics Data System (ADS)

In this talk I will show that several classes of active particles admit an identical coarse-grained description in terms of fluctuating hydrodynamic fields. This equivalence holds as long as the microscopic parameters (e.g. swim speed v, diffusivity or tumbling rate), that may be spatially varying, depend on the local density ? of particles but not on their orientation. This equivalence can thus extend to interacting particles and shows that motility-induced phase separation is generic in these systems: a steeply enough decreasing v(?) generates phase separation in dimensions d=1,2,3. I will discuss the consequences of this phenomenon for pattern formation in bacterial colony and effective temperatures in Active Matter.

Tailleur, Julien

2013-03-01

337

Potential fluctuation associated with the energetic-particle-induced geodesic acoustic mode in the Large Helical Device  

NASA Astrophysics Data System (ADS)

Geodesic acoustic modes (GAM) driven by energetic particles are observed in the Large Helical Device (LHD) by a heavy ion beam probe. The GAM localizes near the magnetic axis. It is confirmed that the energetic-particle-induced GAM is accompanied by an electrostatic potential fluctuation and radial electric field fluctuation. The amplitude of the potential fluctuation is several hundred volts, and it is much larger than the potential fluctuation associated with turbulence-induced GAMs observed in the edge region in tokamak plasmas. The energetic-particle-induced GAM modulates the amplitude of the density fluctuation in a high-frequency range. The observed GAM frequency is constant at the predicted GAM frequency in plasmas with reversed magnetic shear. On the other hand, it shifts upwards from the predicted GAM frequency in plasmas with monotonic magnetic shear.

Ido, T.; Shimizu, A.; Nishiura, M.; Nakamura, S.; Kato, S.; Nakano, H.; Yoshimura, Y.; Toi, K.; Ida, K.; Yoshinuma, M.; Satake, S.; Watanabe, F.; Morita, S.; Goto, M.; Itoh, K.; Kubo, S.; Shimozuma, T.; Igami, H.; Takahashi, H.; Yamada, I.; Narihara, K.; LHD Experiment Group

2011-07-01

338

Amphetamine-induced taste aversion learning in young and old F-344 rats following exposure to 56 Fe particles  

Microsoft Academic Search

Exposure to 56Fe particles produces changes in dopaminergic function and in dopamine-dependent behaviors, including amphetamine-induced\\u000a conditioned taste aversion (CTA) learning. Because many of these changes are characteristic of the changes that accompany\\u000a the aging process, the present study was designed to determine whether or not there would be an interaction between age and\\u000a exposure to 56Fe particles in the disruption

K. L. Carrihill-Knoll; B. M. Rabin; B. Shukitt-Hale; J. A. Joseph; A. Carey

2007-01-01

339

Nuclear physics of cosmic ray interaction with semiconductor materials: Particle-induced soft errors from a physicist's perspective  

Microsoft Academic Search

The key issues of cosmic-ray-induced soft-error rates, SER (also referred to as single-event upset, SEU, rates) in microelectronic devices are discussed from the viewpoint of fundamental atomic and nuclear interactions between high-energy particles and semiconductors. From sea level to moderate altitudes, the cosmic ray spectrum is dominated by three particle species: nucleons (protons and neutrons), pions, and muons. The characteristic

Henry H. K. Tang

1996-01-01

340

The effect of multi-component aerosol particles on quantitative laser-induced breakdown spectroscopy: Consideration of localized matrix effects  

Microsoft Academic Search

Spectral measurements were performed in a laser-induced plasma to assess the changes in sodium or magnesium analyte emission response from particle-derived sources with the addition of concomitant mass to the aerosol particles. Temporally resolved measurements revealed up to a 50% enhancement in analyte emission with the addition of the elements copper, zinc or tungsten at mass ratios from 1:9 to

P. K. Diwakar; P. B. Jackson; D. W. Hahn

2007-01-01

341

Shock-induced Near-wall Two-phase Flow Structure Over a Micron-sized Particles Bed  

Microsoft Academic Search

The present paper studies numerical modelling of near-wall two-phase flows induced by a normal shock wave moving at a constant speed, over a micron-sized particles bed. In this two-fluid model, the possibility of particle trajectory intersection is considered and a full Lagrangian formulation of the dispersed phase is introduced. The finiteness of the Reynolds and Mach numbers of the flow

B. Y. Wang; Y. Xiong; L. X. Qi

2006-01-01

342

Ultrafine titanium dioxide particles in the absence of photoactivation can induce oxidative damage to human bronchial epithelial cells  

Microsoft Academic Search

Ultrafine titanium dioxide (TiO2) particles have been shown to exhibit strong cytotoxicity when exposed to UVA radiation, but are regarded as a biocompatible material in the absence of photoactivation. In contrast to this concept, the present results indicate that anatase-sized (10 and 20nm) TiO2 particles in the absence of photoactivation induced oxidative DNA damage, lipid peroxidation, and micronuclei formation, and

Jia-Ran Gurr; Alexander S. S. Wang; Chien-Hung Chen; Kun-Yan Jan

2005-01-01

343

Defect-induced performance degradation of 4H-SiC Schottky barrier diode particle detectors  

NASA Astrophysics Data System (ADS)

The formation and evolution of defects in 4H-SiC Schottky barrier diode high-energy particle detectors have been investigated and correlated with the detectors' properties. Low temperature annealing at 300 °C is found to significantly recover the charge collection efficiency as degraded by 1 MeV electron irradiation. At higher temperatures, an anneal-induced degradation in the detector's performance is observed. Current-voltage, capacitance-voltage, and deep level transient spectroscopy (DLTS) measurements are used to ascertain the effect of defects on the detector performance. The latter reveals that the DLTS defect levels, EH1 and EH3, are related to the initial recovery of the charge collection efficiency.

Iwamoto, N.; Johnson, B. C.; Hoshino, N.; Ito, M.; Tsuchida, H.; Kojima, K.; Ohshima, T.

2013-04-01

344

Evaluation of Nigerian animal feeds by particle-induced X-ray emission.  

PubMed

There is need to evaluate the locally available animal feeds in Nigeria so as to be able to combine them in acceptable proportions to the animals to achieve the desired growth rate. The technique of particle-induced X-ray emission (PIXE) was employed for the evaluation of these locally available animal feeds, which include Panicum maximum (Guinea grass), Cynodon plectostachyum (grass), Leucaena leucephala (legume), Calopogonium mucunoides (legume), Gliricidia sepium (legume), Euphorbia polychrome (legume), Pueraria phaseloides (legume), and Centrosema pubescens (legume). The proton beam delivered by the 2.5-MV AN 2,000 Van de Graaff accelerator at the International Centre for Theoretical Physics Laboratori Nazionali di Legnaro (LNL), Padova, Italy was used for the PIXE measurements. Twenty-one different elements were detected at various concentrations and their nutritional effects on different animals are discussed. PMID:16217142

Olabanji, S O; Olubunmi, P; Ceccato, D; Buoso, M C; De Poli, M; Moschini, G

2005-11-01

345

Light induced ferromagnetism of nanocrystalline CuCr2Se4 particles  

NASA Astrophysics Data System (ADS)

A novel method to synthesize ternary chalcogenide nanoparticles was developed with microwaveassisted polyol reaction in this study. Copper chloride, chromium acetate and metallic selenium were used as precursors with stoichiometric ratios in poly ethylene glycol. Magnetic moment of CuCr2Se4 nanoparticles was measured from 300 to 750 K with external magnetic field of 500 Oe in argon atmosphere and Curie temperature was calculated as 445 K. Nanocrystalline CuCr2Se4 particles were dispersed in the matrix of light transparent resin so as to investigate light induced effect on the magnetic properties. Light illumination in an external magnetic field increased the magnetization and increment of magnetization ( ?J) to initial magnetization ( J) showed a maximum at 250 Gauss.

Kim, D.; Chung, K. C.; Choi, C. J.

2013-06-01

346

Quantification of arsenic in activated carbon using particle induced X-ray emission  

NASA Astrophysics Data System (ADS)

To date, the trace elemental analysis of solids with inhomogeneous internal structure has been limited, particularly in the case of adsorbents. High-energy ion beam based particle induced X-ray emission (PIXE) is an ideal analytical tool suitable for simultaneous quantification of trace elements with high accuracy. In this study, PIXE was used to quantify arsenic in the adsorbents, granular activated carbon (GAC) and powder activated carbon (PAC). Pelletized and unmodified GAC and PAC samples were analyzed along with powder samples deposited on thin teflon filters. These sample preparation methods resulted in samples of various thicknesses and densities. PIXE measurements taken from these samples were compared to results from neutron activation analysis (NAA) and atomic absorption spectroscopy (AAS). There is a good agreement between the values from the NAA and pelletized PIXE measurements and some AAS measurements.

Yadav, Nirbhay N.; Maheswaran, Saravanamuthu; Shutthanandan, Vaithiyalingam; Thevuthasan, Suntharampillai; Ngo, Huu H.; Vigneswaran, Saravanamuth

2006-09-01

347

Particle-induced X-ray emission (PIXE) analysis of minor and trace elements in gallstones of Nigerian patients.  

PubMed

Gallstone disease is a major health problem in many parts of the world. In Nigeria, however, only a few cases of gallstone disease are reported. Minor/trace elements are reported to play a significant role in the formation of gallstones. This study was conducted to assess the minor elements in gallstone of Nigerian patients who had cholecystectomy in our institution using particle-induced X-ray emission (PIXE) technique. We also compare the findings with previous reports from outside Nigeria. Fourteen patients who had cholecystectomy for calculous cholecystitis at Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife, Nigeria, between March 2006 and July 2008, had the stone retrieved. The stones were analyzed for trace elements at the Center for Energy Research and Developments of the University using PIXE experiments. Certified standard reference material, NIST 1577a (bovine liver), was equally analyzed to confirm the accuracy of the experimental procedure. Computer code GUPIXWIN was used to analyze the data. Fourteen elements, phosphorus, sulfur, chlorine, potassium, calcium, manganese, iron, copper, zinc, bromide, lead, titanium, rubidium, and strontium, were detected in most of the samples. The concentrations of the elements varied in the different samples, ranging from a few parts per million to a few percent. Ca was the major constituent of all samples. The black sand-like samples had very high levels of P, S, K, and Pb, which were different from a previous report. The distribution of trace elements in stones in Nigeria patients is different from previous report outside Nigeria, and this may have some role in the occurrence of gallstones in the black African. PMID:19609492

Alatise, Olusegun I; Obiajunwa, Eusebius I; Lawal, Oladejo O; Adesunkanmi, Abdulrasheed R K

2010-04-01

348

Exposure to wear particles generated from studded tires and pavement induces inflammatory cytokine release from human macrophages.  

PubMed

Health risks associated with exposure to airborne particulate matter (PM) have been shown epidemiologically as well as experimentally, pointing to both respiratory and cardiovascular effects. Lately, wear particles generated from traffic have been recognized to be a major contributing source to the overall particle load, especially in the Nordic countries were studded tires are used. In this work, we investigated the inflammatory effect of PM10 generated from the wear of studded tires on two different types of pavement. As comparison, we also investigated PM10 from a traffic-intensive street, a subway station, and diesel exhaust particles (DEP). Human monocyte-derived macrophages, nasal epithelial cells (RPMI 2650), and bronchial epithelial cells (BEAS-2B) were exposed to the different types of particles, and the secretion of IL-6, IL-8, IL-10, and TNF-alpha into the culture medium was measured. The results show a significant release of cytokines from macrophages after exposure for all types of particles. When particles generated from asphalt/granite pavement were compared to asphalt/quartzite pavement, the granite pavement had a significantly higher capacity to induce the release of cytokines. The granite pavement particles induced cytokine release at the same magnitude as the street particles did, which was higher than what particles from both a subway station and DEP did. Exposure of epithelial cells to PM10 resulted in a significant increase of TNF-alpha secreted from BEAS-2B cells for all types of particles used (DEP was not tested), and the highest levels were induced by subway particles. None of the particle types were able to evoke detectable cytokine release from RPMI 2650 cells. The results indicate that PM10 generated by the wear of studded tires on the street surface is a large contributor to the cytokine-releasing ability of particles in traffic-intensive areas and that the type of pavement used is important for the level of this contribution. Furthermore, the airway inflammatory potential of wear particles from tires and pavement might be of a greater magnitude than that of DEP. PMID:16608163

Lindbom, John; Gustafsson, Mats; Blomqvist, Göran; Dahl, Andreas; Gudmundsson, Anders; Swietlicki, Erik; Ljungman, Anders G

2006-04-01

349

Mechanisms of fibrinogen-induced microvascular dysfunction during cardiovascular disease  

PubMed Central

Fibrinogen (Fg) is a high molecular weight plasma adhesion protein and a biomarker of inflammation. Many cardiovascular and cerebrovascular disorders are accompanied by increased blood content of Fg. Increased levels of Fg result in changes in blood rheological properties such as increases in plasma viscosity, erythrocyte aggregation, platelet thrombogenesis, alterations in vascular reactivity and compromises in endothelial layer integrity. These alterations exacerbate the complications in peripheral blood circulation during cardiovascular diseases such as hypertension, diabetes and stroke. In addition to affecting blood viscosity by altering plasma viscosity and erythrocyte aggregation, growing experimental evidence suggests that Fg alters vascular reactivity and impairs endothelial cell layer integrity by binding to its endothelial cell membrane receptors and activating signalling mechanisms. The purpose of this review is to discuss experimental data, which demonstrate the effects of Fg causing vascular dysfunction and to offer possible mechanisms for these effects, which could exacerbate microcirculatory complications during cardiovascular diseases accompanied by increased Fg content.

Lominadze, D.; Dean, W. L.; Tyagi, S. C.; Roberts, A. M.

2009-01-01

350

[What is new in genetically-induced hair diseases?].  

PubMed

A profound knowledge of specific genetically determined anomalies of the hair may be of considerable value in the diagnosis of genetic syndromes. We give a review of a few recent developments in the field of genetic hair diseases. For example, the brittle hair due to sulphur deficiency (trichothiodystrophy) is nowadays regarded as genetically heterogeneous; three different syndromes can be distinguished: BIDS syndrome, Tay syndrome, and PIBIDS syndrome. Polarization microscopy revealed a striking resemblance of the hair anomalies found in trichothiodystrophy syndromes and those in acrodermatitis enteropathica. This surprising result indicates similar pathophysiological mechanisms. The Comèl-Netherton syndrome--long regarded as representing two different diseases--has recently been recognized as a clinically variable, but genetically homogeneous syndrome, which is most likely based on a single mutation ("lumping"). Minor's sweat test allows the recognition of women heterozygous for X-linked hypohidrotic ectodermal dysplasia and may help to appreciate seemingly non-specific hair findings, such as diffuse alopecia. PMID:2087835

Traupe, H; Hamm, H

1990-12-01

351

Ion permeation inside microgel particles induced by specific interactions: from charge inversion to overcharging.  

PubMed

In this work we have performed a theoretical study of a system formed by ionic microgels in the presence of monovalent salt with the help of Ornstein-Zernike integral equations within the hypernetted-chain (HNC) approximation. We focus in particular on analysing the role that the short-range specific interactions between the polymer fibres of the microgel and the incoming ions have on the equilibrium ion distribution inside and outside the microgel. For this purpose, a theoretical model based on the equilibrium partitioning effect is developed to determine the interaction between the microgel particle and a single ion. The results indicate that when counterions are specifically attracted to the polymer fibres of the microgel, an enhanced counterion accumulation occurs that induces the charge inversion of the microgel and a strong increase of the microgel net charge (or overcharging). In the case of coions, the specific attraction is also able to provoke the coion adsorption even though they are electrostatically repelled, and so increasing the microgel charge (true overcharging). Moreover, we show that ion adsorption onto the microgel particle is very different in swollen and shrunken states due to the competition between specific attraction and steric repulsion. In particular, ion adsorption occurs preferentially in the internal core of the particle for swollen states, whereas it is mainly concentrated in the external shell for de-swollen configurations. Finally, we observe the existence of a critical salt concentration, where the net charge of the microgels vanishes; above this inversion point the net charge of the microgels increases again, thus leading to reentrant stability of microgel suspensions. PMID:24974885

Moncho-Jordá, A; Adroher-Benítez, I

2014-08-21

352

A model for vehicle-induced non-tailpipe emissions of particles along Swedish roads  

NASA Astrophysics Data System (ADS)

One of the most important parameters that controls the suspension of road dust particles in the air is road surface moisture. This is calculated every hour from a budget equation that takes into account precipitation, evaporation and runoff. During wet conditions a road dust layer is built up from road wear which strongly depends on the use of studded tyres and road sanding. The dust layer is reduced during dry road conditions by suspension of particles due to vehicle-induced turbulence. The dust layer is also reduced by wash-off due to precipitation. Direct non-tailpipe vehicle emissions due to the wear and tear of the road surface, brakes and tyres are accounted for in the traditional way as constant emission factors expressed as mass emitted per vehicle kilometre. The model results are compared with measurements from both a narrow street canyon in the city centre of Stockholm and from an open highway outside the city. The model is able to account for the main features in the day-to-day mean PM 10 variability for the street canyon and for the highway. A peak in the PM 10 concentration is typically observed in late winter and early spring in the Nordic countries where studded tyres are used. This behaviour is due to a combination of factors: frequent conditions with dry roads, high number of cars with studded tyres and an accumulated road dust layer that increases suspension of particles. The study shows that using a constant emission factor for PM 10 or relating PM 10 emissions to NO x cannot be used for prediction of day-to-day variations in PM 10 concentrations in the traffic environments studied here. The model needs to describe variations in dust load, wetness of the road and how dust suspension interacts with these processes.

Omstedt, G.; Bringfelt, B.; Johansson, C.

353

Energetic-particle-driven instabilities and induced fast-ion transport in a reversed field pincha)  

NASA Astrophysics Data System (ADS)

Multiple bursty energetic-particle (EP) driven modes with fishbone-like structure are observed during 1 MW tangential neutral-beam injection in a reversed field pinch (RFP) device. The distinguishing features of the RFP, including large magnetic shear (tending to add stability) and weak toroidal magnetic field (leading to stronger drive), provide a complementary environment to tokamak and stellarator configurations for exploring basic understanding of EP instabilities. Detailed measurements of the EP mode characteristics and temporal-spatial dynamics reveal their influence on fast ion transport. Density fluctuations exhibit a dynamically evolving, inboard-outboard asymmetric spatial structure that peaks in the core where fast ions reside. The measured mode frequencies are close to the computed shear Alfvén frequency, a feature consistent with continuum modes destabilized by strong drive. The frequency pattern of the dominant mode depends on the fast-ion species. Multiple frequencies occur with deuterium fast ions compared to single frequency for hydrogen fast ions. Furthermore, as the safety factor (q) decreases, the toroidal mode number of the dominant EP mode transits from n =5 to n =6 while retaining the same poloidal mode number m =1. The transition occurs when the m =1, n =5 wave-particle resonance condition cannot be satisfied as the fast-ion safety factor (qfi) decreases. The fast-ion temporal dynamics, measured by a neutral particle analyzer, resemble a classical predator-prey relaxation oscillation. It contains a slow-growth phase arising from the beam fueling followed by a rapid drop when the EP modes peak, indicating that the fluctuation-induced transport maintains a stiff fast-ion density profile. The inferred transport rate is strongly enhanced with the onset of multiple EP modes.

Lin, L.; Anderson, J. K.; Brower, D. L.; Capecchi, W.; Ding, W. X.; Eilerman, S.; Forest, C. B.; Koliner, J. J.; Liu, D.; Nornberg, M. D.; Reusch, J.; Sarff, J. S.

2014-05-01

354

Spatial learning and memory deficits induced by exposure to iron-56-particle radiation  

NASA Technical Reports Server (NTRS)

It has previously been shown that exposing rats to particles of high energy and charge (HZE) disrupts the functioning of the dopaminergic system and behaviors mediated by this system, such as motor performance and an amphetamine-induced conditioned taste aversion; these adverse behavioral and neuronal effects are similar to those seen in aged animals. Because cognition declines with age, spatial learning and memory were assessed in the Morris water maze 1 month after whole-body irradiation with 1.5 Gy of 1 GeV/nucleon high-energy (56)Fe particles, to test the cognitive behavioral consequences of radiation exposure. Irradiated rats demonstrated cognitive impairment compared to the control group as seen in their increased latencies to find the hidden platform, particularly on the reversal day when the platform was moved to the opposite quadrant. Also, the irradiated group used nonspatial strategies during the probe trials (swim with no platform), i.e. less time spent in the platform quadrant, fewer crossings of and less time spent in the previous platform location, and longer latencies to the previous platform location. These findings are similar to those seen in aged rats, suggesting that an increased release of reactive oxygen species may be responsible for the induction of radiation- and age-related cognitive deficits. If these decrements in behavior also occur in humans, they may impair the ability of astronauts to perform critical tasks during long-term space travel beyond the magnetosphere.

Shukitt-Hale, B.; Casadesus, G.; McEwen, J. J.; Rabin, B. M.; Joseph, J. A.

2000-01-01

355

Mechanism of vibration-induced repulsion force on a particle in a viscous fluid cell.  

PubMed

Space platforms such as the Space Shuttle and International Space Station have been considered an ideal environment for production of protein and semiconductor crystals of superior quality due to the negligible gravity-induced convection. Although it was believed that under microgravity environment diffusive mass transport would dominate the growth of the crystals, some related experiments have not shown satisfactory results possibly due to the movement of the growing crystals in fluid cells caused by small vibrations present in the space platforms called g-jitter. In ground-based experiments, there have been clear observations of attraction and repulsion of a solid particle with respect to a nearby wall of the fluid cell due to small vibrations. The present work is a numerical investigation on the physical mechanisms responsible for the repulsion force, which has been predicted to increase with the cell vibration frequency and amplitude, as well as the fluid viscosity. Moreover, the simulations have revealed that the repulsion force occurs mostly due to the increased pressure in the narrow gap between the particle and the nearest wall. PMID:24032936

Saadatmand, Mehrrad; Kawaji, Masahiro

2013-08-01

356

Mechanism of vibration-induced repulsion force on a particle in a viscous fluid cell  

NASA Astrophysics Data System (ADS)

Space platforms such as the Space Shuttle and International Space Station have been considered an ideal environment for production of protein and semiconductor crystals of superior quality due to the negligible gravity-induced convection. Although it was believed that under microgravity environment diffusive mass transport would dominate the growth of the crystals, some related experiments have not shown satisfactory results possibly due to the movement of the growing crystals in fluid cells caused by small vibrations present in the space platforms called g-jitter. In ground-based experiments, there have been clear observations of attraction and repulsion of a solid particle with respect to a nearby wall of the fluid cell due to small vibrations. The present work is a numerical investigation on the physical mechanisms responsible for the repulsion force, which has been predicted to increase with the cell vibration frequency and amplitude, as well as the fluid viscosity. Moreover, the simulations have revealed that the repulsion force occurs mostly due to the increased pressure in the narrow gap between the particle and the nearest wall.

Saadatmand, Mehrrad; Kawaji, Masahiro

2013-08-01

357

Thermally induced light-driven microfluidics using a MOEMS-based laser scanner for particle manipulation  

NASA Astrophysics Data System (ADS)

One key challenge in the field of microfluidics and lab-on-a-chip experiments for biological or chemical applications is the remote manipulation of fluids, droplets and particles. These can be volume elements of reactants, particles coated with markers, cells or many others. Light-driven microfluidics is one way of accomplishing this challenge. In our work, we manipulated micrometre sized polystyrene beads in a microfluidic environment by inducing thermal flows. Therefore, the beads were held statically in an unstructured microfluidic chamber, containing a dyed watery solution. Inside this chamber, the beads were moved along arbitrary trajectories on a micrometre scale. The experiments were performed, using a MOEMS (micro-opto-electro-mechanical-systems)-based laser scanner with a variable focal length. This scanner system is integrated in a compact device, which is flexibly applicable to various microscope setups. The device utilizes a novel approach for varying the focal length, using an electrically tunable lens. A quasi statically driven MOEMS mirror is used for beam steering. The combination of a tunable lens and a dual axis micromirror makes the device very compact and robust and is capable of positioning the laser focus at any arbitrary location within a three dimensional working space. Hence, the developed device constitutes a valuable extension to manually executed microfluidic lab-on-chip experiments.

Kremer, Matthias P.; Tortschanoff, Andreas

2014-03-01

358

Induced Systemic Resistance in Biocontrol of Plant Diseases  

Microsoft Academic Search

\\u000a Induction of resistance to pathogens by some strains of plant growth-promoting rhizobacteria (PGPR) and other microorganisms\\u000a is termed induced systemic resistance (ISR). In contrast to systemic acquired resistance, ISR develops as a result of the\\u000a colonization of plant roots by PGPR and other plant-beneficial microorganisms. ISR is mediated predominantly by a jasmonate-\\u000a or ethylene-sensitive pathway. Some strains of Pseudomonas, Bacillus,

Sudhamoy Mandal; Ramesh C. Ray

359

MECHANISMS OF ACTION OF INHALED FIBERS, PARTICLES AND NANOPARTICLES IN LUNG AND CARDIOVASCULAR DISEASES  

EPA Science Inventory

ABSTRACT: A symposium on the mechanisms of action of inhaled airborne particulate matter (PM),pathogenic particles and fibers such as silica and asbestos, and nanomaterials, defined as synthetic particles or fibers less than 100 nm in diameter, was held on October 27 and 28, ...

360

Concentrated ambient ultrafine particle exposure induces cardiac change in young healthy volunteers  

EPA Science Inventory

Exposure to ambient ultrafine particles has been associated with cardiopulmonary toxicity and mortality. Adverse effects specifically linked to ultrafine particles include loss of sympathovagal balance and altered hemostasis. To characterize the effects of ultrafine particles in ...

361

Transmission dynamics of Tasmanian devil facial tumor disease may lead to disease-induced extinction.  

PubMed

Most pathogens threatening to cause extinction of a host species are maintained on one or more reservoir hosts, in addition to the species that is threatened by disease. Further, most conventional host-pathogen theory assumes that transmission is related to host density, and therefore a pathogen should become extinct before its sole host. Tasmanian devil facial tumor disease is a recently emerged infectious cancer that has led to massive population declines and grave concerns for the future persistence of this largest surviving marsupial carnivore. Here we report the results of mark-recapture studies at six sites and use these data to estimate epidemiological parameters critical to both accurately assessing the risk of extinction from this disease and effectively managing this disease threat. Three sites were monitored from before or close to the time of disease arrival, and at three others disease was well established when trapping began, in one site for at least 10 years. We found no evidence for sex-specific differences in disease prevalence and little evidence of consistent seasonal variation in the force of infection. At all sites, the disease was maintained at high levels of prevalence (>50% in 2-3-year-old animals), despite causing major population declines. We also provide the first estimates of the basic reproductive rate R0 for this disease. Using a simple age-structured deterministic model, we show that our results are not consistent with transmission being proportional to the density of infected hosts but are consistent with frequency-dependent transmission. This conclusion is further supported by the observation that local disease prevalence in 2-3-year-olds still exceeds 50% at a site where population density has been reduced by up to 90% in the past 12 years. These findings lend considerable weight to concerns that this host-specific pathogen will cause the extinction of the Tasmanian devil. Our study highlights the importance of rapidly implementing monitoring programs to determine how transmission depends on host density and emphasizes the need for ongoing management strategies involving a disease-free "insurance population," along with ongoing field monitoring programs to confirm whether local population extinction occurs. PMID:20120807

McCallum, Hamish; Jones, Menna; Hawkins, Clare; Hamede, Rodrigo; Lachish, Shelly; Sinn, David L; Beeton, Nick; Lazenby, Billie

2009-12-01

362

Spectral characterization of biological aerosol particles using two-wavelength excited laser-induced fluorescence and elastic scattering measurements.  

PubMed

A two-wavelength laser-induced fluorescence (LIF) instrument has been developed and used to characterize individual biological aerosol particles, including biological warfare (BW) agent surrogates. Fluorescence in discrete spectral bands from widely different species, and also from similar species under different growth conditions were measured and compared. The two-wavelength excitation approach was found to increase discrimination among several biological materials, and especially with respect to diesel exhaust particles, a common interferent for LIF BW detection systems. The spectral characteristics of a variety of biological materials and ambient air components have been studied as a function of aerosol particle size and incident fluence. PMID:21451645

Sivaprakasam, Vasanthi; Lin, Horn-Bond; Huston, Alan L; Eversole, Jay D

2011-03-28

363

Propagation of high-energy particles inside solid matter - Cosmic-ray-induced spallation in iron meteorites  

NASA Astrophysics Data System (ADS)

A model for evaluating the variations with depth of high-energy particle fluxes propagating inside spherical solid bodies is proposed for use in calculating the production rates of spallogenic nuclides in meteorites. It is shown that the production by secondary particles is the major process determining the abundances of the produced nuclides. The angular distribution of these particles is of little incidence. The model is restricted to energies above 300 MeV. Results are presented from application of the model to the products of high-energy reactions induced in iron meteorites.

Zanda, B.; Malinie, G.; Audouze, J.

1989-09-01

364

Role of Mutagenicity in Asbestos Fiber-Induced Carcinogenicity and Other Diseases  

PubMed Central

The cellular and molecular mechanisms of how asbestos fibers induce cancers and other diseases are not well understood. Both serpentine and amphibole asbestos fibers have been shown to induce oxidative stress, inflammatory responses, cellular toxicity and tissue injuries, genetic changes, and epigenetic alterations in target cells in vitro and tissues in vivo. Most of these mechanisms are believe to be shared by both fiber-induced cancers and noncancerous diseases. This article summarizes the findings from existing literature with a focus on genetic changes, specifically, mutagenicity of asbestos fibers. Thus far, experimental evidence suggesting the involvement of mutagenesis in asbestos carcinogenicity is more convincing than asbestos-induced fibrotic diseases. The potential contributions of mutagenicity to asbestos-induced diseases, with an emphasis on carcinogenicity, are reviewed from five aspects: (1) whether there is a mutagenic mode of action (MOA) in fiber-induced carcinogenesis; (2) mutagenicity/carcinogenicity at low dose; (3) biological activities that contribute to mutagenicity and impact of target tissue/cell type; (4) health endpoints with or without mutagenicity as a key event; and finally, (5) determinant factors of toxicity in mutagenicity. At the end of this review, a consensus statement of what is known, what is believed to be factual but requires confirmation, and existing data gaps, as well as future research needs and directions, is provided.

Huang, Sarah X. L.; Jaurand, Marie-Claude; Kamp, David W.; Whysner, John; Hei, Tom K.

2011-01-01

365

Ropinirole-induced Pisa syndrome in Parkinson disease.  

PubMed

Pisa syndrome (PS), also known as pleurothotonus, is an abnormal posture characterized by lateral flexion of the trunk that typically disappears in supine position. In Parkinson disease (PD), an abnormal forward flexion of the trunk (defined as camptocormia) is a common observation and has been interpreted as a sign of dystonia. Few reports have described PS mainly related to dopaminergic therapy in this kind of patients.Levodopa/carbidopa, levodopa/benserazide, levodopa/carbidopa/entacapone, pergolide, and pramipexole may cause PS, whereas no reports for ropinirole have been described.Here, we describe a case of a patient with PD who developed severe and reversible PS due to ropinirole intake. PMID:24614668

Galati, Salvatore; Möller, Jens Carsten; Städler, Claudio

2014-01-01

366

Involvement of oxidative stress in motorcycle exhaust particle-induced DNA damage and inhibition of intercellular communication  

Microsoft Academic Search

In this study, we investigated the involvement of reactive oxygen species (ROS) in the motorcycle exhaust particle (MEP)-induced genotoxic and non-genotoxic activity in mammalian cell systems. Initially, the capability of MEP to induce ROS was evaluated by using 2?,7?-dichlorofluorescin diacetate (DCFH-DA) to detect hydrogen peroxide (H2O2). A five-fold increase in H2O2 was observed in Chinese hamster lung V79 and human

Min-Liang Kuo; Shiou-Hwa Jee; Ming-Hong Chou; Tzuu-Huei Ueng

1998-01-01

367

Chemical Inducers of Autophagy That Enhance the Clearance of Mutant Proteins in Neurodegenerative Diseases*  

PubMed Central

Many of the neurodegenerative diseases that afflict people are caused by intracytoplasmic aggregate-prone proteins. These include Parkinson disease, tauopathies, and polyglutamine expansion diseases such as Huntington disease. In Mendelian forms of these diseases, the mutations generally confer toxic novel functions on the relevant proteins. Thus, one potential strategy for dealing with these mutant proteins is to enhance their degradation. This can be achieved by up-regulating macroautophagy, which we will henceforth call autophagy. In this minireview, we will consider the reasons why autophagy up-regulation may be a powerful strategy for these diseases. In addition, we will consider some of the drugs and associated signaling pathways that can be used to induce autophagy with these therapeutic aims in mind.

Renna, Maurizio; Jimenez-Sanchez, Maria; Sarkar, Sovan; Rubinsztein, David C.

2010-01-01

368

Wear particles promote endotoxin tolerance in macrophages by inducing interleukin-1 receptor-associated kinase-M expression.  

PubMed

Toll-like receptors (TLRs) recognizing pathogen-associated molecular patterns (PAMP) play a role in local immunity and participate in implant-associated loosening. TLRs-mediated signaling is regulated by interleukin-1 receptor-associated kinase-M (IRAK-M). Our previous studies have proved that IRAK-M is induced by wear particles in macrophages from periprosthetic tissues. In this study, the IRAK-M-related mechanisms were further explored by lipopolysaccharide (LPS) and/or titanium (Ti) particles stimulations and small interfering RNAs (siRNAs). The protein level of IRAK-M was studied using western blotting and tumor necrosis factor-? (TNF-?), and interleukin-1? (IL-1?) levels were measured using ELISA. Results showed that in RAW264.7 cells stimulated by LPS after Ti particle pre-exposure, IRAK-M was slightly changed, compared with LPS stimulation. And levels of TNF-? and IL-1? in cultures stimulated by LPS first after Ti particle pre-exposure were lower than in the other two groups which were stimulated by LPS with or without Ti particles (p < 0.001), whereas there were no statistic differences between the later two (p > 0.05). The cytokines were lowest in Ti particles alone stimulation. After siRNAs silenced, IRAK-M-deficient cells exhibited increased expression of the cytokines in LPS stimulation after Ti particle pre-exposure and when stimulated with Ti particles alone. Our findings suggest that debris-induced IRAK-M decreases foreign body reactions, but at the same time, the over-expression of IRAK-M may also be detrimental on local intrusion of PAMPs or bacteria, negatively regulates the LPS-induced and TLRs-mediated inflammation and results in immunosuppression in periprosthetic tissue, which may predispose to implant-associated infections. PMID:22941946

Zhang, Yangchun; Yu, Shiming; Xiao, Jianhong; Hou, Changhe; Li, Ziqing; Zhang, Ziji; Zhai, Qiyi; Lehto, Matti; Konttinen, Yrjö T; Sheng, Puyi

2013-03-01

369

Carotid Stenting for Post-Endarterectomy Restenosis and Radiation-Induced Occlusive Disease  

PubMed Central

Surgical treatment of carotid restenosis and radiation-induced occlusive disease is challenging because of the high morbidity and mortality associated with this procedure. Carotid stenting has been proposed as an alternative approach. We report a series of 8 patients who were treated via the percutaneous approach for either carotid restenosis (n = 4) or radiation-induced occlusive disease (n = 4). Technical success was achieved in all of the cases. There have been no deaths or strokes during the periprocedural or follow-up period. After dilation of the extracranial vessel, 1 patient experienced severe intracranial internal carotid arterial spasm that required stent placement. Wallstents® were used in 6 patients and S.M.A.R.T.™ stents were used in the remaining 2. Restenosis occurred in 2 patients and was treated successfully with redilation or restenting. Carotid stenting appears to be a feasible and safe alternative to surgery for restenosis after carotid endarterectomy and for radiation-induced occlusive disease.

Hernandez-Vila, Eduardo; Strickman, Neil E.; Skolkin, Mark; Toombs, Barry D.; Krajcer, Zvonimir

2000-01-01

370

Newcastle disease virus-like particles as a platform for the development of vaccines for human and agricultural pathogens  

PubMed Central

Vaccination is the single most effective way to control viral diseases. However, many currently used vaccines have safety concerns, efficacy issues or production problems. For other viral pathogens, classic approaches to vaccine development have, thus far, been unsuccessful. Virus-like particles (VLPs) are increasingly being considered as vaccine candidates because they offer significant advantages over many currently used vaccines or developing vaccine technologies. VLPs formed with structural proteins of Newcastle disease virus, an avian paramyxovirus, are a potential vaccine candidate for Newcastle disease in poultry. More importantly, these VLPs are a novel, uniquely versatile VLP platform for the rapid construction of effective vaccine candidates for many human pathogens, including genetically complex viruses and viruses for which no vaccines currently exist.

Morrison, Trudy G

2011-01-01

371

Glutathione-S-transferase M1 regulation of diesel exhaust particle-induced pro-inflammatory mediator expression in normal human bronchial epithelial cells  

PubMed Central

Background Diesel exhaust particles (DEP) contribute substantially to ambient particulate matter (PM) air pollution in urban areas. Inhalation of PM has been associated with increased incidence of lung disease in susceptible populations. We have demonstrated that the glutathione S-transferase M1 (GSTM1) null genotype could aggravate DEP-induced airway inflammation in human subjects. Given the critical role airway epithelial cells play in the pathogenesis of airway inflammation, we established the GSTM1 deficiency condition in primary bronchial epithelial cells from human volunteers with GSTM1 sufficient genotype (GSTM1+) using GSTM1 shRNA to determine whether GSTM1 deficiency could exaggerate DEP-induced expression of interleukin-8 (IL-8) and IL-1? proteins. Furthermore, the mechanisms underlying GSTM1 regulation of DEP-induced IL-8 and IL-1? expression were also investigated. Methods IL-8 and IL-1? protein levels were measured using enzyme-linked immunosorbent assay. GSTM1 deficiency in primary human bronchial epithelial cells was achieved using lentiviral GSTM1 shRNA particles and verified using real-time polymerase chain reaction and immunoblotting. Intracellular reactive oxygen species (ROS) production was evaluated using flow cytometry. Phosphorylation of protein kinases was detected using immunoblotting. Results Exposure of primary human bronchial epithelial cells (GSTM1+) to 25-100??g/ml DEP for 24?h significantly increased IL-8 and IL-1? protein expression. Knockdown of GSTM1 in these cells further elevated DEP-induced IL-8 and IL-1? expression, implying that GSTM1 deficiency aggravated DEP-induced pro-inflammatory response. DEP stimulation induced the phosphorylation of extracellular signal-regulated kinase (ERK) and Akt, the downstream kinase of phosphoinositide 3-kinase (PI3K), in GSTM1+ bronchial epithelial cells. Pharmacological inhibition of ERK kinase and PI3K activity blocked DEP-induced IL-8 and IL-1? expression. DEP-induced ERK and Akt phosphorylation could be increased by GSTM1 knockdown. In addition, pretreatment of HBEC with the antioxidant N-acetyl cysteine significantly inhibited DEP-induced ERK and Akt phosphorylation, and subsequent IL-8 and IL-1? expression. Conclusion GSTM1 regulates DEP-induced IL-8 and IL-1? expression in primary human bronchial epithelial cells by modulation of ROS, ERK and Akt signaling.

2012-01-01

372

Tumbling motion of magnetic particles on a magnetic substrate induced by a rotational magnetic field  

Microsoft Academic Search

We analyze the dynamics of paramagnetic particles on a paramagnetic substrate under a rotational magnetic field. When the paramagnetic particles are subjected to a rotational magnetic field, the rotational plane of which is perpendicular to the substrate surface, the particles form chain clusters caused by the dipole-dipole interaction between the particles and these clusters display a tumbling motion under certain

Hisao Morimoto; Tomofumi Ukai; Yutaka Nagaoka; Nicole Grobert; Toru Maekawa

2008-01-01

373

Protective Effect of Curcumin on Pulmonary and Cardiovascular Effects Induced by Repeated Exposure to Diesel Exhaust Particles in Mice  

Microsoft Academic Search

Particulate air pollution has been associated with increased risk of cardiopulmonary diseases. However, the underlying mechanisms are not fully understood. We have previously demonstrated that single dose exposure to diesel exhaust particle (DEP) causes lung inflammation and peripheral thrombotic events. Here, we exposed mice with repeated doses of DEP (15µg\\/animal) every 2nd day for 6 days (a total of 4

Abderrahim Nemmar; Deepa Subramaniyan; Badreldin H. Ali

2012-01-01

374

Seizure-induced MRI changes mimicking metastatic brain disease.  

PubMed

Non-convulsive status epilepticus (NCSE) can present with heterogeneous clinical manifestations including prolonged confusion. MRI of the brain may demonstrate enhancing signal abnormalities that can mimic various pathologies including disease progression in patients with brain tumour. These neuroimaging changes are usually reversible and have been attributed to a combination of cytotoxic and vasogenic oedema. We report an interesting patient with a past history of prostatic rhabdomyosarcoma and brain metastasis presenting with NCSE where brain MRI demonstrated marked left hemispheric signal abnormalities, raising concerns about tumour recurrence. However the neuroimaging changes resolved following treatment with intravenous anticonvulsants, confirming that they were an effect rather than the cause of seizures. Recognition of seizure-related imaging abnormalities is important to institute prompt appropriate treatment, and to avoid diagnostic ambiguity and unnecessary treatment and/or investigations. PMID:24184175

Chhetri, Suresh Kumar; Mathur, Sachin; Soh, Calvin; Gosal, David

2014-05-01

375

Deregulated Cdk5 Activity Is Involved in Inducing Alzheimer's Disease  

PubMed Central

Alzheimer’s disease (AD), the most devastating chronic neurodegenerative disease in adults, causes dementia and eventually, death of the affected individuals. Clinically, AD is characterized as late-onset, age-dependent cognitive decline due to loss of neurons in cortex and hippocampus. The pathologic corollary of these symptoms is the formation of senile plaques and neurofibrillary tangles. Senile plaques are formed due to accumulation of oligomeric amyloid beta (A?) forming fibrillary plaques. This occurs due to the amyloidogenic processing of the amyloid precursor protein (APP) by various secretases. On the other hand, neurofibrillary tangles are formed due to hyperphosphorylation of cytoskeleton proteins like tau and neurofilament. Both are hyperphosphorylated by cyclin-dependent kinase-5 (Cdk5) and are part of the paired helical filament (PHF), an integral part of neurofibrillary tangles. Unlike other cyclin-dependent kinases, Cdk5 plays a very important role in the neuronal development. Cdk5 gets activated by its neuronal activators p35 and p39. Upon stress, p35 and p39 are cleaved by calpain resulting in truncated products as p25 and p29. Association of Cdk5/p25 is longer and uncontrolled causing aberrant hyperphosphorylation of various substrates of Cdk5 like APP, tau and neurofilament, leading to neurodegenerative pathology like AD. Additionally recent evidence has shown increased levels of p25, A?, hyperactivity of Cdk5, phosphorylated tau and neurofilament in human AD brains. This review briefly describes the above-mentioned aspects of involvement of Cdk5 in the pathology of AD and at the end summarizes the advances in Cdk5 as a therapeutic target.

Shukla, Varsha; Skuntz, Susan; Pant, Harish C.

2012-01-01

376

MicroRNAs and Induced Pluripotent Stem Cells for Human Disease Mouse Modeling  

PubMed Central

Human disease animal models are absolutely invaluable tools for our understanding of mechanisms involved in both physiological and pathological processes. By studying various genetic abnormalities in these organisms we can get a better insight into potential candidate genes responsible for human disease development. To this point a mouse represents one of the most used and convenient species for human disease modeling. Hundreds if not thousands of inbred, congenic, and transgenic mouse models have been created and are now extensively utilized in the research labs worldwide. Importantly, pluripotent stem cells play a significant role in developing new genetically engineered mice with the desired human disease-like phenotype. Induced pluripotent stem (iPS) cells which represent reprogramming of somatic cells into pluripotent stem cells represent a significant advancement in research armament. The novel application of microRNA manipulation both in the generation of iPS cells and subsequent lineage-directed differentiation is discussed. Potential applications of induced pluripotent stem cell—a relatively new type of pluripotent stem cells—for human disease modeling by employing human iPS cells derived from normal and diseased somatic cells and iPS cells derived from mouse models of human disease may lead to uncovering of disease mechanisms and novel therapies.

Underbayev, Chingiz; Kasar, Siddha; Yuan, Yao; Raveche, Elizabeth

2012-01-01

377

Oncogene-induced senescence as a new mechanism of disease: the paradigm of erdheim-chester disease.  

PubMed

Erdheim-Chester disease (ECD) is a rare form of systemic histiocytosis characterized by the diffuse infiltration of tissues by lipid-laden macrophages. As the clinical course and prognosis are highly influenced by site of disease involvement, ECD course ranges from asymptomatic to life threatening, with a reported global 5-year mortality of 30-40%. Whether ECD is an inflammatory or clonal disease in its nature has long been debated. The disease is characterized by a network of pro-inflammatory cyto/chemokines responsible for the recruitment and activation of histiocytes into ECD lesions, similarly to what reported in Langerhans cell histiocytosis (LCH). Growing evidence supports a central role of the oncogenic BRAF(V600E) mutation in histiocytosis pathogenesis, and suggests oncogene-induced senescence (OIS), a major protective mechanism against oncogenic events characterized by cell-cycle arrest and the induction of pro-inflammatory molecules, as the possible link between the oncogenic mutation and the observed inflammation. Indeed, ECD recapitulates in vivo the molecular events associated with OIS, i.e., cell-cycle arrest and a potent local inflammatory response. Accordingly, the infiltration of different tissues by macrophages and the inflammatory local and systemic effects observed in ECD likely represent a drawback of OIS. Therefore, these findings delineate a new conception of OIS as a new pathogenic mechanism intrinsically responsible for disease development. PMID:24982657

Cavalli, Giulio; Biavasco, Riccardo; Borgiani, Bruno; Dagna, Lorenzo

2014-01-01

378

Oncogene-Induced Senescence as a New Mechanism of Disease: The Paradigm of Erdheim-Chester Disease  

PubMed Central

Erdheim–Chester disease (ECD) is a rare form of systemic histiocytosis characterized by the diffuse infiltration of tissues by lipid-laden macrophages. As the clinical course and prognosis are highly influenced by site of disease involvement, ECD course ranges from asymptomatic to life threatening, with a reported global 5-year mortality of 30–40%. Whether ECD is an inflammatory or clonal disease in its nature has long been debated. The disease is characterized by a network of pro-inflammatory cyto/chemokines responsible for the recruitment and activation of histiocytes into ECD lesions, similarly to what reported in Langerhans cell histiocytosis (LCH). Growing evidence supports a central role of the oncogenic BRAFV600E mutation in histiocytosis pathogenesis, and suggests oncogene-induced senescence (OIS), a major protective mechanism against oncogenic events characterized by cell-cycle arrest and the induction of pro-inflammatory molecules, as the possible link between the oncogenic mutation and the observed inflammation. Indeed, ECD recapitulates in vivo the molecular events associated with OIS, i.e., cell-cycle arrest and a potent local inflammatory response. Accordingly, the infiltration of different tissues by macrophages and the inflammatory local and systemic effects observed in ECD likely represent a drawback of OIS. Therefore, these findings delineate a new conception of OIS as a new pathogenic mechanism intrinsically responsible for disease development.

Cavalli, Giulio; Biavasco, Riccardo; Borgiani, Bruno; Dagna, Lorenzo

2014-01-01

379

Infliximab treatment induces apoptosis of lamina propria T lymphocytes in Crohn's disease  

PubMed Central

Background and aims: Treatment with infliximab induces remission in about 70% of patients with steroid refractory Crohn's disease. Because Crohn's disease is considered to be mediated by uncontrolled activation of mucosal T lymphocytes, we hypothesised that infliximab could induce apoptosis of T lymphocytes. Methods: Induction of apoptosis in vivo was studied in 10 patients with therapy refractory Crohn's disease. In vitro, resting or stimulated Jurkat T cells were incubated with infliximab. Results: Infusion of infliximab (5 mg/kg) in steroid refractory patients with Crohn's disease induced a clinical response in 9/10 patients but did not influence expression of activation markers, homing receptors, memory cells, Fas expression, or Bax/Bcl-2 expression on peripheral blood T lymphocytes. In contrast, a significant increase in CD3 and TUNEL positive cells within colonic biopsies was detected 24 hours after infusion of infliximab, suggesting that infliximab stimulates apoptosis of activated T lymphocytes but not of resting T cells. To test this hypothesis, the effects of infliximab on Jurkat T cells were investigated. We observed that infliximab induced apoptosis and an increase in the Bax/Bcl-2 ratio of CD3/CD28 stimulated Jurkat T cells but not of unstimulated Jurkat cells. Conclusions: Our data indicate that infliximab treatment causes a rapid and specific increase in apoptosis of T lymphocytes in the gut mucosa. These findings may explain the rapid and sustained therapeutic effects of infliximab in Crohn's disease.

ten Hove, T; van Montfrans, C; Peppelenbosch, M P; van Deventer, S J H

2002-01-01

380

Challenges in pulmonary fibrosis ? 4: Smoking-induced diffuse interstitial lung diseases  

PubMed Central

Smoking?induced diffuse interstitial lung processes include respiratory bronchiolitis, respiratory bronchiolitis?associated interstitial lung disease (RBILD), desquamative interstitial pneumonia (DIP) and Langerhans' cell histiocytosis. The histological, radiological and clinical features of respiratory bronchiolitis, RBILD and DIP are reviewed, with particular reference to management issues; Langerhans' cell histiocytosis is covered elsewhere in this series of articles. Possible relationships between smoking and other diffuse lung diseases are explored briefly.

Wells, Athol U; Nicholson, Andrew G; Hansell, David M

2007-01-01

381

Mucosal cytokine production in radiation-induced proctosigmoiditis compared with inflammatory bowel disease  

Microsoft Academic Search

OBJECTIVE:We measured the mucosal levels of interleukin 1? (IL-1?), IL-2, IL-6, and IL-8 in affected segments of radiation-induced proctosigmoiditis and compared these with the levels in normal controls and inflammatory bowel disease (IBD) patients.METHODS:Thirteen patients with histologically proven radiation proctosigmoiditis, 32 patients with active ulcerative colitis (UC), 35 patients with Crohn’s disease, and 15 normal subjects undergoing routine colonoscopy were

Anant V. K Indaram; Vernu Visvalingam; Mitch Locke; Simmy Bank

2000-01-01

382

Mucosal cytokine production in radiation-induced proctosigmoiditis compared with inflammatory bowel disease  

Microsoft Academic Search

OBJECTIVE:We measured the mucosal levels of interleukin 1? (IL-1?), IL-2, IL-6, and IL-8 in affected segments of radiation-induced proctosigmoiditis and compared these with the levels in normal controls and inflammatory bowel disease (IBD) patients.METHODS:Thirteen patients with histologically proven radiation proctosigmoiditis, 32 patients with active ulcerative colitis (UC), 35 patients with Crohn's disease, and 15 normal subjects undergoing routine colonoscopy were

Anant V. K. Indaram; Vernu Visvalingam; Mitch Locke; Simmy Bank

2000-01-01

383

Recombinant prion protein induces a new transmissible prion disease in wild-type animals  

Microsoft Academic Search

Prion disease is a neurodegenerative malady, which is believed to be transmitted via a prion protein in its abnormal conformation\\u000a (PrPSc). Previous studies have failed to demonstrate that prion disease could be induced in wild-type animals using recombinant\\u000a prion protein (rPrP) produced in Escherichia coli. Here, we report that prion infectivity was generated in Syrian hamsters after inoculating full-length rPrP

Natallia Makarava; Gabor G. Kovacs; Olga Bocharova; Regina Savtchenko; Irina Alexeeva; Herbert Budka; Robert G. Rohwer; Ilia V. Baskakov

2010-01-01

384

Human iPSC-based modeling of late-onset disease via progerin-induced aging.  

PubMed

Reprogramming somatic cells to induced pluripotent stem cells (iPSCs) resets their identity back to an embryonic age and, thus, presents a significant hurdle for modeling late-onset disorders. In this study, we describe a strategy for inducing aging-related features in human iPSC-derived lineages and apply it to the modeling of Parkinson's disease (PD). Our approach involves expression of progerin, a truncated form of lamin A associated with premature aging. We found that expression of progerin in iPSC-derived fibroblasts and neurons induces multiple aging-related markers and characteristics, including dopamine-specific phenotypes such as neuromelanin accumulation. Induced aging in PD iPSC-derived dopamine neurons revealed disease phenotypes that require both aging and genetic susceptibility, such as pronounced dendrite degeneration, progressive loss of tyrosine hydroxylase (TH) expression, and enlarged mitochondria or Lewy-body-precursor inclusions. Thus, our study suggests that progerin-induced aging can be used to reveal late-onset age-related disease features in hiPSC-based disease models. PMID:24315443

Miller, Justine D; Ganat, Yosif M; Kishinevsky, Sarah; Bowman, Robert L; Liu, Becky; Tu, Edmund Y; Mandal, Pankaj K; Vera, Elsa; Shim, Jae-won; Kriks, Sonja; Taldone, Tony; Fusaki, Noemi; Tomishima, Mark J; Krainc, Dimitri; Milner, Teresa A; Rossi, Derrick J; Studer, Lorenz

2013-12-01

385

Mathematical model for the secondary infection of infectious disease with incorporated the disease induced death rate  

Microsoft Academic Search

We construct the mathematical model and consider the secondary infection cases and the death rate from the dengue virus infection with clinical diagnosis are incorporated into Susceptible-Infectious-Recovered-Susceptible mathematical model. This paper, we use the real data in Thailand between 1997 and 2010. The model exhibits two equilibrium states are locally asymptotically stable, the disease free and the endemic equilibrium states.

Rujira Kongnuy; Ekachai Naowanich

2011-01-01

386

Mapping of brain function after MPTP-induced neurotoxicity in a primate Parkinson's disease model  

Microsoft Academic Search

Neurophysiological studies of the brain in normal and Parkinson's disease (PD) patients have indicated intricate connections for basal ganglia-induced control of signaling into the motor cortex. To investigate if similar mechanisms are controlling function in the primate brain (Macaca fascicularis) after MPTP-induced neurotoxicity, we conducted PET studies of cerebral blood flow, oxygen and glucose metabolism, dopamine transporter, and D2 receptor

Anna-Liisa Brownell; Kelly Canales; Y. Iris Chen; Bruce G Jenkins; Christopher Owen; Elijahu Livni; Meixiang Yu; Francesca Cicchetti; Rosario Sanchez-Pernaute; Ole Isacson

2003-01-01

387

Analysis of neutron emission spectra for 30 50 MeV alpha-particle induced reactions in thick targets  

Microsoft Academic Search

Comparisons of calculated neutron yield distributions from alpha-particle induced reactions on thick targets are made with measured data to analyze the initial reaction process in the framework of the exciton (hybrid) model code ALICE91 (M. Blann, Lawrence Livermore National Laboratory Report UCID 19614, 1982). We have considered two reaction mechanisms: dissolution of the alpha in the nuclear field, and preequilibrium

D. Dhar; S. N. Roy; Maitreyee Nandy; P. K. Sarkar

2003-01-01

388

Quantitative evaluation of the prosthetic head damage induced by microscopic third-body particles in total hip replacement.  

PubMed

The increase of the femoral head roughness in artificial hip joints is strongly influenced by the presence of abrasive particulate entrapped between the articulating surfaces. The aim of the present study is to evaluate the dependence of such damage on the geometry of the particles entrapped in the joint, with reference to the UHMWPE/chrome-cobalt coupling. Five chrome-cobalt femoral heads and their coupled UHMWPE acetabular cups, retrieved at revision surgery after a short period of in situ functioning, have been investigated for the occurrence of third-body damage. This was found on all the prosthetic heads, where the peak-to-valley height of the scratches, as derived from profilometry evaluations, ranged from 0.3-1.3 microm. The observed damage has been divided into four classes, related to the particle motion while being embedded into the polymer. Two kinds of particle morphology have been studied, spherical and prismatic, with size ranging from 5-50 microm. In order to provide an estimation of the damage induced by such particles, a finite element model of the third-body interaction was set up. The peak-to-valley height of the impression due to the particle indentation on the chrome-cobalt surface is assumed as an index of the induced damage. The calculated values range from 0.1-0.5 microm for spherical particles of size ranging from 10-40 microm. In the case of prismatic particles, the peak-to-valley height can reach 1.3 microm and depends both on the size and width of the particle's free corner, indenting the chrome-cobalt. As an example, a sharp-edged particle of size 30 microm can induce on the chrome-cobalt an impression with peak-to-valley height of 0.75 microm, when embedded into the polyethylene with a free edge of 5 microm facing the metallic surface. Negligible damage is induced, if a free edge of 7.5 microm is indenting the counterface. Our findings offer new support to the hypothesis that microscopic third-body particles are capable of causing increased roughening of the femoral head and provide a quantitative evaluation of the phenomenon. PMID:11410903

Raimondi, M T; Vena, P; Pietrabissa, R

2001-01-01

389

Integrity of Membrane Lipid Rafts Is Necessary for the Ordered Assembly and Release of Infectious Newcastle Disease Virus Particles  

PubMed Central

Membrane lipid raft domains are thought to be sites of assembly for many enveloped viruses. The roles of both classical lipid rafts and lipid rafts associated with the membrane cytoskeleton in the assembly of Newcastle disease virus (NDV) were investigated. The lipid raft-associated proteins caveolin-1, flotillin-2, and actin were incorporated into virions, while the non-lipid raft-associated transferrin receptor was excluded. Kinetic analyses of the distribution of viral proteins in lipid rafts, as defined by detergent-resistant membranes (DRMs), in non-lipid raft membranes, and in virions showed an accumulation of HN, F, and NP viral proteins in lipid rafts early after synthesis. Subsequently, these proteins exited the DRMs and were recovered quantitatively in purified virions, while levels of these proteins in detergent-soluble cell fractions remained relatively constant. Cholesterol depletion of infected cells drastically altered the association of viral proteins with DRMs and resulted in an enhanced release of virus particles with reduced infectivity. Decreased infectivity was not due to effects on subsequent virus entry, since the extraction of cholesterol from intact virus did not significantly reduce infectivity. Particles released from cholesterol-depleted cells had very heterogeneous densities and altered ratios of NP and glycoproteins, demonstrating structural abnormalities which potentially contributed to their lowered infectivity. Taken together, these results indicate that lipid rafts, including cytoskeleton-associated lipid rafts, are sites of NDV assembly and that these domains are important for ordered assembly and release of infectious Newcastle disease virus particles.

Laliberte, Jason P.; McGinnes, Lori W.; Peeples, Mark E.; Morrison, Trudy G.

2006-01-01

390

Luteolin Reduces Alzheimer's Disease Pathologies Induced by Traumatic Brain Injury  

PubMed Central

Traumatic brain injury (TBI) occurs in response to an acute insult to the head and is recognized as a major risk factor for Alzheimer’s disease (AD). Indeed, recent studies have suggested a pathological overlap between TBI and AD, with both conditions exhibiting amyloid-beta (A?) deposits, tauopathy, and neuroinflammation. Additional studies involving animal models of AD indicate that some AD-related genotypic determinants may be critical factors enhancing temporal and phenotypic symptoms of TBI. Thus in the present study, we examined sub-acute effects of moderate TBI delivered by a gas-driven shock tube device in A? depositing Tg2576 mice. Three days later, significant increases in b-amyloid deposition, glycogen synthase-3 (GSK-3) activation, phospho-tau, and pro-inflammatory cytokines were observed. Importantly, peripheral treatment with the naturally occurring flavonoid, luteolin, significantly abolished these accelerated pathologies. This study lays the groundwork for a safe and natural compound that could prevent or treat TBI with minimal or no deleterious side effects in combat personnel and others at risk or who have experienced TBI.

Sawmiller, Darrell; Li, Song; Shahaduzzaman, Md; Smith, Adam J.; Obregon, Demian; Giunta, Brian; Borlongan, Cesar V.; Sanberg, Paul R.; Tan, Jun

2014-01-01

391

Luteolin reduces Alzheimer's disease pathologies induced by traumatic brain injury.  

PubMed

Traumatic brain injury (TBI) occurs in response to an acute insult to the head and is recognized as a major risk factor for Alzheimer's disease (AD). Indeed, recent studies have suggested a pathological overlap between TBI and AD, with both conditions exhibiting amyloid-beta (A?) deposits, tauopathy, and neuroinflammation. Additional studies involving animal models of AD indicate that some AD-related genotypic determinants may be critical factors enhancing temporal and phenotypic symptoms of TBI. Thus in the present study, we examined sub-acute effects of moderate TBI delivered by a gas-driven shock tube device in A? depositing Tg2576 mice. Three days later, significant increases in b-amyloid deposition, glycogen synthase-3 (GSK-3) activation, phospho-tau, and pro-inflammatory cytokines were observed. Importantly, peripheral treatment with the naturally occurring flavonoid, luteolin, significantly abolished these accelerated pathologies. This study lays the groundwork for a safe and natural compound that could prevent or treat TBI with minimal or no deleterious side effects in combat personnel and others at risk or who have experienced TBI. PMID:24413756

Sawmiller, Darrell; Li, Song; Shahaduzzaman, Md; Smith, Adam J; Obregon, Demian; Giunta, Brian; Borlongan, Cesar V; Sanberg, Paul R; Tan, Jun

2014-01-01

392

Hedgehog/Notch-induced premature gliogenesis represents a new disease mechanism for Hirschsprung disease in mice and humans.  

PubMed

Hirschsprung (HSCR) disease is a complex genetic disorder attributed to a failure of the enteric neural crest cells (ENCCs) to form ganglia in the hindgut. Hedgehog and Notch are implicated in mediating proliferation and differentiation of ENCCs. Nevertheless, how these signaling molecules may interact to mediate gut colonization by ENCCs and contribute to a primary etiology for HSCR are not known. Here, we report our pathway-based epistasis analysis of data generated by a genome-wide association study on HSCR disease, which indicates that specific genotype constellations of Patched (PTCH1) (which encodes a receptor for Hedgehog) and delta-like 3 (DLL3) (which encodes a receptor for Notch) SNPs confer higher risk to HSCR. Importantly, deletion of Ptch1 in mouse ENCCs induced robust Dll1 expression and activation of the Notch pathway, leading to premature gliogenesis and reduction of ENCC progenitors in mutant bowels. Dll1 integrated Hedgehog and Notch pathways to coordinate neuronal and glial cell differentiation during enteric nervous system development. In addition, Hedgehog-mediated gliogenesis was found to be highly conserved, such that Hedgehog was consistently able to promote gliogenesis of human neural crest-related precursors. Collectively, we defined PTCH1 and DLL3 as HSCR susceptibility genes and suggest that Hedgehog/Notch-induced premature gliogenesis may represent a new disease mechanism for HSCR. PMID:21841314

Ngan, Elly Sau-Wai; Garcia-Barceló, Maria-Mercè; Yip, Benjamin Hon-Kei; Poon, Hiu-Ching; Lau, Sin-Ting; Kwok, Carmen Ka-Man; Sat, Eric; Sham, Mai-Har; Wong, Kenneth Kak-Yuen; Wainwright, Brandon J; Cherny, Stacey S; Hui, Chi-Chung; Sham, Pak Chung; Lui, Vincent Chi-Hang; Tam, Paul Kwong-Hang

2011-09-01

393

Hedgehog/Notch-induced premature gliogenesis represents a new disease mechanism for Hirschsprung disease in mice and humans  

PubMed Central

Hirschsprung (HSCR) disease is a complex genetic disorder attributed to a failure of the enteric neural crest cells (ENCCs) to form ganglia in the hindgut. Hedgehog and Notch are implicated in mediating proliferation and differentiation of ENCCs. Nevertheless, how these signaling molecules may interact to mediate gut colonization by ENCCs and contribute to a primary etiology for HSCR are not known. Here, we report our pathway-based epistasis analysis of data generated by a genome-wide association study on HSCR disease, which indicates that specific genotype constellations of Patched (PTCH1) (which encodes a receptor for Hedgehog) and delta-like 3 (DLL3) (which encodes a receptor for Notch) SNPs confer higher risk to HSCR. Importantly, deletion of Ptch1 in mouse ENCCs induced robust Dll1 expression and activation of the Notch pathway, leading to premature gliogenesis and reduction of ENCC progenitors in mutant bowels. Dll1 integrated Hedgehog and Notch pathways to coordinate neuronal and glial cell differentiation during enteric nervous system development. In addition, Hedgehog-mediated gliogenesis was found to be highly conserved, such that Hedgehog was consistently able to promote gliogenesis of human neural crest–related precursors. Collectively, we defined PTCH1 and DLL3 as HSCR susceptibility genes and suggest that Hedgehog/Notch-induced premature gliogenesis may represent a new disease mechanism for HSCR.

Ngan, Elly Sau-Wai; Garcia-Barcelo, Maria-Merce; Yip, Benjamin Hon-Kei; Poon, Hiu-Ching; Lau, Sin-Ting; Kwok, Carmen Ka-Man; Sat, Eric; Sham, Mai-Har; Wong, Kenneth Kak-Yuen; Wainwright, Brandon J.; Cherny, Stacey S.; Hui, Chi-Chung; Sham, Pak Chung; Lui, Vincent Chi-Hang; Tam, Paul Kwong-Hang

2011-01-01

394

Determination of neutron-induced alpha-particle cross sections on carbon using the response of a liquid scintillation detector  

SciTech Connect

This paper presents the sums of the cross section {sup 12}C(n, {alpha}{sub 0}) {sup 9}Be and {sup 12}C(n, N{prime}3{alpha}) determined in the neutron energy range between 7.4 and 11 MeV. An NE-213 scintillation detector is simultaneously used as a carbon target, an alpha-particle detector, and a neutron fluence monitor. By comparing the measured and calculated response spectra, the neutron-induced alpha-particle events in the scintillation volume are separated and the cross sections {sigma}{sub n,{alpha}0} + {sigma}{sub n,n{prime}3{alpha}} are determined relative to the n-p scattering cross section. The pulse-height distribution due to alpha particles allows the angular distribution to be extracted on the basis of the reaction kinematics and an accurately determined light output function for alpha particles in the NE-213 detector.

Brede, H.J.; Dietze, G.; Klein, H.; Schoelermann, H. (Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-3300 Braunschweig (DE))

1991-01-01

395

Gravitational perturbation of the BTZ black hole induced by test particles and weak cosmic censorship in AdS spacetime  

NASA Astrophysics Data System (ADS)

We analyze the gravitational perturbations induced by particles falling into a three dimensional, asymptotically AdS black hole geometry. More specifically, we solve the linearized perturbation equations obtained from the geodesic motion of a ringlike distribution of test particles in the BTZ background. This setup ensures that the U(1) symmetry of the background is preserved. The nonasymptotic flatness of the background raises difficulties in attributing the significance of energy and angular momentum to the conserved quantities of the test particles. This issue is well known but, to the best of our knowledge, has never been addressed in the literature. We confirm that the naive expressions for energy and angular momentum are the correct definitions. Finally, we put an asymptotically AdS version of the weak cosmic censorship to a test: by attempting to overspin the BTZ black hole with test particles it is found that the black hole cannot be spun-up past its extremal limit.

Rocha, Jorge V.; Cardoso, Vitor

2011-05-01

396

Effects of heavy particle irradiation and diet on amphetamine- and lithium chloride-induced taste avoidance learning in rats  

NASA Technical Reports Server (NTRS)

Rats were maintained on diets containing either 2% blueberry or strawberry extract or a control diet for 8 weeks prior to being exposed to 1.5 Gy of 56Fe particles in the Alternating Gradient Synchrotron at Brookhaven National Laboratory. Three days following irradiation, the rats were tested for the effects of irradiation on the acquisition of an amphetamine- or lithium chloride-induced (LiCl) conditioned taste avoidance (CTA). The rats maintained on the control diet failed to show the acquisition of a CTA following injection of amphetamine. In contrast, the rats maintained on antioxidant diets (strawberry or blueberry extract) continued to show the development of an amphetamine-induced CTA following exposure to 56Fe particles. Neither irradiation nor diet had an effect on the acquisition of a LiCl-induced CTA. The results are interpreted as indicating that oxidative stress following exposure to 56Fe particles may be responsible for the disruption of the dopamine-mediated amphetamine-induced CTA in rats fed control diets; and that a reduction in oxidative stress produced by the antioxidant diets functions to reinstate the dopamine-mediated CTA. The failure of either irradiation or diet to influence LiCl-induced responding suggests that oxidative stress may not be involved in CTA learning following injection of LiCl.

Rabin, Bernard M.; Shukitt-Hale, Barbara; Szprengiel, Aleksandra; Joseph, James A.

2002-01-01

397

Gut microbiome composition and function in experimental colitis during active disease and treatment-induced remission.  

PubMed

Dysregulated immune responses to gut microbes are central to inflammatory bowel disease (IBD), and gut microbial activity can fuel chronic inflammation. Examining how IBD-directed therapies influence gut microbiomes may identify microbial community features integral to mitigating disease and maintaining health. However, IBD patients often receive multiple treatments during disease flares, confounding such analyses. Preclinical models of IBD with well-defined disease courses and opportunities for controlled treatment exposures provide a valuable solution. Here, we surveyed the gut microbiome of the T-bet(-/-) Rag2(-/-) mouse model of colitis during active disease and treatment-induced remission. Microbial features modified among these conditions included altered potential for carbohydrate and energy metabolism and bacterial pathogenesis, specifically cell motility