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Sample records for brain swelling due

  1. [Persistent Disturbance of Consciousness after Clipping of an Unruptured Cerebral Aneurysm due to Pseudohypoxic Brain Swelling].

    PubMed

    Masamura, Tomona; Kurita, Akihide; Yamamoto, Takashi; Yamada, Keisuke; Yamamoto, Ken

    2015-04-01

    A patient developed persistent disturbance of consciousness after uneventful clipping of an unruptured cerebral aneurysm under general anesthesia. Pseudohypoxic brain swelling (PHBS) was suspected because computerized tomography (CT) and magnetic resonance imaging (MRI) revealed diffuse brain swelling, especially in the bilateral basal ganglia and thalami. Steroid pulse therapy in addition to antiedematous drugs and anticonvulsant improved the consciousness. Anesthesiologists should pay attention to PHBS in a case of persistent disturbance of consciousness after uneventful craniotomy.

  2. Cardiac arrest due to intracranial hypotension following pseudohypoxic brain swelling induced by negative suction drainage in a cranioplasty patient: a case report.

    PubMed

    Moon, Hyun-Soo; Lee, Soo Kyung; Kim, Su Ryun; Kim, Seon Ju

    2016-06-01

    Pseudohypoxic brain swelling (PHBS) is known to be an uncommon event that may occur during and following an uneventful brain surgery, when negative suction drainage is used. The cerebrospinal fluid loss related to suction drainage can evoke intracranial hypotension that progress to PHBS. The main presentations of PHBS are sudden unexpected circulatory collapses, such as severe bradycardia, hypotension, cardiac arrest, consciousness deterioration and diffuse brain swelling as seen with brain computerized tomography (CT). We present a stuporous 22-year-old patient who underwent cranioplasty under general anesthesia. The entire course of the general anesthesia and operation progressed favorably. However, the time of scalp suture completion, sudden bradycardia and hypotension occurred, followed by cardiac arrest immediately after initiation of subgaleal and epidural suction drainage. After successful resuscitation, the comatose patient was transferred to the neurosurgical intensive care unit and PHBS was confirmed using brain CT. PMID:27274378

  3. Cardiac arrest due to intracranial hypotension following pseudohypoxic brain swelling induced by negative suction drainage in a cranioplasty patient: a case report

    PubMed Central

    Kim, Su Ryun; Kim, Seon Ju

    2016-01-01

    Pseudohypoxic brain swelling (PHBS) is known to be an uncommon event that may occur during and following an uneventful brain surgery, when negative suction drainage is used. The cerebrospinal fluid loss related to suction drainage can evoke intracranial hypotension that progress to PHBS. The main presentations of PHBS are sudden unexpected circulatory collapses, such as severe bradycardia, hypotension, cardiac arrest, consciousness deterioration and diffuse brain swelling as seen with brain computerized tomography (CT). We present a stuporous 22-year-old patient who underwent cranioplasty under general anesthesia. The entire course of the general anesthesia and operation progressed favorably. However, the time of scalp suture completion, sudden bradycardia and hypotension occurred, followed by cardiac arrest immediately after initiation of subgaleal and epidural suction drainage. After successful resuscitation, the comatose patient was transferred to the neurosurgical intensive care unit and PHBS was confirmed using brain CT. PMID:27274378

  4. Microchannel deformations due to solvent-induced PDMS swelling.

    PubMed

    Dangla, Rémi; Gallaire, François; Baroud, Charles N

    2010-11-01

    The compatibility of polydimethylsiloxane (PDMS) channels with certain solvents is a well known problem of soft lithography techniques, in particular when it leads to the swelling of the PDMS blocks. However, little is known about the modification of microchannel geometries when they are subjected to swelling solvents. Here, we experimentally measure the deformations of the roof of PDMS microchannels due to such solvents. The dynamics of impregnation of the solvents in PDMS and its relation to volume dilation are first addressed in a model experiment, allowing the precise measurement of the diffusion coefficients of oils in PDMS. When Hexadecane, a swelling solvent, fills a microchannel 1 mm in width and 50 μm in height, we measure that the channel roof bends inwards and takes a parabolic shape with a maximum deformation of 7 μm. The amplitude of the subsidence is found to increase with the channel width, reaching 28 μm for a 2 mm wide test section. On the other hand, perfluorinated oils do not swell the PDMS and the microchannel geometry is not affected by the presence of perfluorodecalin. Finally, we observe that the trajectories of droplets flowing in this microchannel are strongly affected by the deformations: drops carried by swelling oils are pushed towards the edges of the channel while those carried by non-swelling oils remain in the channel center. PMID:20848011

  5. Brain Swelling and Death in Children with Cerebral Malaria

    PubMed Central

    Seydel, Karl B.; Kampondeni, Samuel D.; Valim, Clarissa; Potchen, Michael J.; Milner, Danny A.; Muwalo, Francis W.; Birbeck, Gretchen L.; Bradley, William G.; Fox, Lindsay L.; Glover, Simon J.; Hammond, Colleen A.; Heyderman, Robert S.; Chilingulo, Cowles A.; Molyneux, Malcolm E.; Taylor, Terrie E.

    2015-01-01

    BACKGROUND Case fatality rates among African children with cerebral malaria remain in the range of 15 to 25%. The key pathogenetic processes and causes of death are unknown, but a combination of clinical observations and pathological findings suggests that increased brain volume leading to raised intracranial pressure may play a role. Magnetic resonance imaging (MRI) became available in Malawi in 2009, and we used it to investigate the role of brain swelling in the pathogenesis of fatal cerebral malaria in African children. METHODS We enrolled children who met a stringent definition of cerebral malaria (one that included the presence of retinopathy), characterized them in detail clinically, and obtained MRI scans on admission and daily thereafter while coma persisted. RESULTS Of 348 children admitted with cerebral malaria (as defined by the World Health Organization), 168 met the inclusion criteria, underwent all investigations, and were included in the analysis. A total of 25 children (15%) died, 21 of whom (84%) had evidence of severe brain swelling on MRI at admission. In contrast, evidence of severe brain swelling was seen on MRI in 39 of 143 survivors (27%). Serial MRI scans showed evidence of decreasing brain volume in the survivors who had had brain swelling initially. CONCLUSIONS Increased brain volume was seen in children who died from cerebral malaria but was uncommon in those who did not die from the disease, a finding that suggests that raised intracranial pressure may contribute to a fatal outcome. The natural history indicates that increased intracranial pressure is transient in survivors. (Funded by the National Institutes of Health and Wellcome Trust U.K.) PMID:25785970

  6. Swelling

    MedlinePlus

    ... syndrome Poor nutrition Pregnancy Thyroid disease Too little albumin in the blood (hypoalbuminemia) Too much salt or ... the swelling. Tests that may be done include: Albumin blood test Blood electrolyte levels Echocardiography ECG Kidney ...

  7. Sarcoidosis detected due to tattoo swellings in an Indian female.

    PubMed

    Ghorpade, Ashok

    2015-01-01

    A female patient presented with asymptomatic swellings in old blue-black tattoo marks of her forearms. On careful skin examination, few raised erythematous, circular plaques were also found on the non-tattooed skin on her back, about which she was unaware. The diagnosis of cutaneous and systemic sarcoidosis was confirmed after classical histopathological findings from skin lesions from her non tattooed back and from papulonodular tattooed lesions, ruling out other causes of granulomas and supported by a negative Mantoux test, raised serum angiotensin converting enzyme level, high resolution computed tomography thorax, etc. She responded well to oral steroid therapy. The importance of a careful skin examination, easy access provided by skin lesions in suspected cases of cutaneous/systemic sarcoidosis, the value of sudden tattoo changes in the diagnosis here and the possible contribution of tattoos toward the causation of cutaneous and/or systemic sarcoidosis are highlighted. PMID:26275266

  8. Pseudohypoxic brain swelling after elective clipping of an unruptured anterior communicating artery aneurysm.

    PubMed

    Yokota, Hiroshi; Yokoyama, Kazuhiro; Miyamoto, Kazunori; Nishioka, Toshikazu

    2009-12-01

    A case of pseudohypoxic brain swelling, a newly defined entity, is described. The patient experienced generalized seizures and did not awake initially after a seemingly uneventful elective craniotomy for clipping of an unruptured anterior communicating artery aneurysm. Neuroimaging findings demonstrated diffuse brain swelling, especially in the bilateral basal ganglia and thalami. The rarity of this postoperative complication is addressed and the pathogenesis discussed.

  9. Optical scatter imaging of cellular and mitochondrial swelling in brain tissue models of stroke

    NASA Astrophysics Data System (ADS)

    Johnson, Lee James

    2001-08-01

    The severity of brain edema resulting from a stroke can determine a patient's survival and the extent of their recovery. Cellular swelling is the microscopic source of a significant part of brain edema. Mitochondrial swelling also appears to be a determining event in the death or survival of the cells that are injured during a stroke. Therapies for reducing brain edema are not effective in many cases and current treatments of stroke do not address mitochondrial swelling at all. This dissertation is motivated by the lack of a complete understanding of cellular swelling resulting from stroke and the lack of a good method to begin to study mitochondrial swelling resulting from stroke in living brain tissue. In this dissertation, a novel method of detecting mitochondrial and cellular swelling in living hippocampal slices is developed and validated. The system is used to obtain spatial and temporal information about cellular and mitochondrial swelling resulting from various models of stroke. The effect of changes in water content on light scatter and absorption are examined in two models of brain edema. The results of this study demonstrate that optical techniques can be used to detect changes in water content. Mie scatter theory, the theoretical basis of the dual- angle scatter ratio imaging system, is presented. Computer simulations based on Mie scatter theory are used to determine the optimal angles for imaging. A detailed account of the early systems is presented to explain the motivations for the system design, especially polarization, wavelength and light path. Mitochondrial sized latex particles are used to determine the system response to changes in scattering particle size and concentration. The dual-angle scatter ratio imaging system is used to distinguish between osmotic and excitotoxic models of stroke injury. Such distinction cannot be achieved using the current techniques to study cellular swelling in hippocampal slices. The change in the scatter ratio is

  10. Sulfonylurea Receptor 1 Contributes to the Astrocyte Swelling and Brain Edema in Acute Liver Failure

    PubMed Central

    Jayakumar, A.R.; Valdes, V.; Tong, X.Y.; Shamaladevi, N.; Gonzalez, W.; Norenberg, M.D.

    2014-01-01

    Astrocyte swelling (cytotoxic brain edema) is the major neurological complication of acute liver failure (ALF), a condition in which ammonia has been strongly implicated in its etiology. Ion channels and transporters are known to be involved in cell volume regulation and a disturbance in these systems may result in cell swelling. One ion channel known to contribute to astrocyte swelling/brain edema in other neurological disorders is the ATP-dependent, non-selective cation channel (NCCa-ATP channel). We therefore examined its potential role in the astrocyte swelling/brain edema associated with ALF. Cultured astrocytes treated with 5 mM ammonia showed a 3-fold increase in the sulfonylurea receptor type 1 (SUR1) protein expression, a marker of NCCa-ATP channel activity. Blocking SUR1 with glibenclamide significantly reduced the ammonia-induced cell swelling in cultured astrocytes. Additionally, overexpression of SUR1 in ammonia-treated cultured astrocytes was significantly reduced by co-treatment of cells with BAY 11-7082, an inhibitor of NF-κB, indicating the involvement of an NF-κB-mediated SUR1 upregulation in the mechanism of ammonia-induced astrocyte swelling. Brain SUR1 mRNA level was also found to be increased in the thioacetamide (TAA) rat model of ALF. Additionally, we found a significant increase in SUR1 protein expression in rat brain cortical astrocytes in TAA-treated rats. Treatment with glibenclamide significantly reduced the brain edema in this model of ALF. These findings strongly suggest the involvement of NCCa-ATP channel in the astrocyte swelling/brain edema in ALF, and that targeting this channel may represent a useful approach for the treatment of the brain edema associated with ALF. PMID:24443056

  11. Thermodynamic model for swelling of unconfined coal due to adsorption of mixed gases

    NASA Astrophysics Data System (ADS)

    Liu, Jinfeng; Peach, Colin; Spiers, Christopher

    2013-04-01

    Permeability evolution in coal reservoirs during CO2-Enhanced Coalbed Methane (ECBM) production is strongly influenced by swelling/shrinkage effects related to sorption and desorption of both CO2 and CH4. Other gases, such as N2, may perhaps also be used in ECBM operations. Much work has been done on the sorption/swelling response of coal to the pure gases. However, there is a clear need for an improved understanding of swelling behaviour of coal matrix material as a result of mixed gas adsorption. We therefore constructed a thermodynamic model for swelling of unconfined coal due to mixed gases adsorption, considering the equilibrium state (swelling strain eadseq), focusing initially on a binary gas mixture. Following Hol et al (2012, IJCG, 93, 1-15), we started with the following basic assumptions: a) nanoporous coal matrix material only allows diffusion and adsorption, b) the matrix hosts nsi(i=α, β) localised adsorption sites for the two gas components α and β, c) the material is homogeneous in structure and composition but may be anisotropic in properties as appropriate for natural coal, d) adsorption is allowed to proceed until equilibrium is reached, at which point the chemical potential of the adsorbed component i is equal to the potential of the free component phase i, and e) the volume change (strain) associated with adsorption of one molecule of component i is insensitive to the adsorbed concentration of either component. Three models were derived corresponding to three possible interactions: 1) Isolated adsorption sites model. This assumes that each component has its own specific adsorption sites. Adsorption of α and β accordingly leads to independent swelling responses that sum to give total volumetric strain. 2) Shared adsorption sites model. This postulates that both gases have full access to all adsorption sites (nsα = nsβ = ns). This model is thermodynamically equivalent to the Extended Langmuir model. If the free fluids behave as ideal

  12. Beware of delayed severe brain swelling after intracerebral haematoma in HELLP syndrome

    PubMed Central

    Bodkin, PA; Labram, EK; Shetty, A

    2013-01-01

    Haemolysis, elevated liver enzymes and low platelets (HELLP) syndrome is a condition associated with increased risk of adverse outcomes during pregnancy and peripartum, including neurological complications. We report the third case in the world literature of delayed brain swelling following cerebral haemorrhage as a complication of HELLP syndrome. A 36-year-old woman in labour developed HELLP, which was complicated with intracerebral haematoma. This was evacuated, but motor impairment persisted after surgery and unfortunately the patient died unexpectedly during the 11th postoperative day. Computer tomographic brain scans documented diffuse cerebral swelling, which we think may have been caused by cerebral vasospasm. Cerebral vasospasm should always be considered when managing patients who suffered from stroke complicating HELLP syndrome. Close monitoring is advised even in later stages of recovery.

  13. Mathematical model of the effect of ischemia-reperfusion on brain capillary collapse and tissue swelling.

    PubMed

    Mohamed Mokhtarudin, M J; Payne, S J

    2015-05-01

    Restoration of an adequate cerebral blood supply after an ischemic attack is a primary clinical goal. However, the blood-brain barrier may break down after a prolonged ischemia causing the fluid in the blood plasma to filtrate and accumulate into the cerebral tissue interstitial space. Accumulation of this filtration fluid causes the cerebral tissue to swell, a condition known as vasogenic oedema. Tissue swelling causes the cerebral microvessels to be compressed, which may further obstruct the blood flow into the tissue, thus leading to the no-reflow phenomenon or a secondary ischemic stroke. The actual mechanism of this however is still not fully understood. A new model is developed here to study the effect of reperfusion on the formation of vasogenic oedema and cerebral microvessel collapse. The formation of vasogenic oedema is modelled using the capillary filtration equation while vessel collapse is modelled using the tube law of microvessel. Tissue swelling is quantified in terms of displacement, which is modelled using poroelastic theory. The results show that there is an increase in tissue displacement and interstitial pressure after reperfusion. In addition, the results also show that vessel collapse can occur at high value of reperfusion pressure, low blood osmotic pressure, high cerebral capillary permeability and low cerebral capillary stiffness. This model provides insight on the formation of ischemia-reperfusion injury by tissue swelling and vessel collapse. PMID:25749185

  14. Oxidative stress and brain mitochondria swelling induced by endosulfan and protective role of quercetin in rat.

    PubMed

    Lakroun, Zhoura; Kebieche, Mohamed; Lahouel, Asma; Zama, Djamila; Desor, Frederique; Soulimani, Rachid

    2015-05-01

    The neurological damages resulted by endosulfan poisoning is not completely elucidated, especially in cellular organelles such as mitochondria. In the present study, the pro-oxidant effect of endosulfan on brain mitochondria was first investigated. Gavages of endosulfan into rats at the dose of 2 mg/kg induced oxidative stress in this organelle since it provokes a significant reduction of catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) level. In addition, a significant increase in mitochondria swelling and malondialdehyde (MDA) levels were observed in neuronal mitochondria, indicating clearly an intense peroxidation within mitochondria. Second, the protective effect of quercetin (QE) (10 mg/kg) against endosulfan-induced oxidative stress in mitochondria was also assessed. Indeed, the pretreatment of rats with QE protects brain mitochondria from oxidative stress, lipid peroxidation, and mitochondria swelling induced by endosulfan. The activities of antioxidant enzymes and the mitochondrial content of GSH and MDA were returned to control values. Thus, although endosulfan can have neurotoxic effects in brain rats, this toxicity can be prevented by quercetin.

  15. Dimensional errors in LIGA-produced metal structures due to thermal expansion and swelling of PMMA.

    SciTech Connect

    Kistler, Bruce L.; Dryden, Andrew S.; Crowell, Jeffrey A.W.; Griffiths, Stewart K.

    2004-04-01

    Numerical methods are used to examine dimensional errors in metal structures microfabricated by the LIGA process. These errors result from elastic displacements of the PMMA mold during electrodeposition and arise from thermal expansion of the PMMA when electroforming is performed at elevated temperatures and from PMMA swelling due to absorption of water from aqueous electrolytes. Both numerical solutions and simple analytical approximations describing PMMA displacements for idealized linear and axisymmetric geometries are presented and discussed. We find that such displacements result in tapered metal structures having sidewall slopes up to 14 {micro}m per millimeter of height for linear structures bounded by large areas of PMMA. Tapers for curved structures are of similar magnitude, but these structures are additionally skewed from the vertical. Potential remedies for reducing dimensional errors are also discussed. Here we find that auxiliary moat-like features patterned into the PMMA surrounding mold cavities can reduce taper by an order of magnitude or more. Such moats dramatically reduce tapers for all structures, but increase skew for curved structures when the radius of curvature is comparable to the structure height.

  16. Swelling-induced changes in coal microstructure due to supercritical CO2 injection

    NASA Astrophysics Data System (ADS)

    Zhang, Yihuai; Lebedev, Maxim; Sarmadivaleh, Mohammad; Barifcani, Ahmed; Iglauer, Stefan

    2016-09-01

    Enhanced coalbed methane recovery and CO2 geostorage in coal seams are severely limited by permeability decrease caused by CO2 injection and associated coal matrix swelling. Typically, it is assumed that matrix swelling leads to coal cleat closure, and as a consequence, permeability is reduced. However, this assumption has not yet been directly observed. Using a novel in situ reservoir condition X-ray microcomputed tomography flooding apparatus, for the first time we observed such microcleat closure induced by supercritical CO2 flooding in situ. Furthermore, fracturing of the mineral phase (embedded in the coal) was observed; this fracturing was induced by the internal swelling stress. We conclude that coal permeability is drastically reduced by cleat closure, which again is caused by coal matrix swelling, which again is caused by flooding with supercritical CO2.

  17. Reversible brain swelling in crucian carp (Carassius carassius) and goldfish (Carassius auratus) in response to high external ammonia and anoxia.

    PubMed

    Wilkie, Michael P; Stecyk, Jonathan A W; Couturier, Christine S; Sidhu, Sanya; Sandvik, Guro K; Nilsson, Göran E

    2015-06-01

    Increased internal ammonia (hyperammonemia) and ischemic/anoxic insults are known to result in a cascade of deleterious events that can culminate in potentially fatal brain swelling in mammals. It is less clear, however, if the brains of fishes respond to ammonia in a similar manner. The present study demonstrated that the crucian carp (Carassius carassius) was not only able to endure high environmental ammonia exposure (HEA; 2 to 22 mmol L(-1)) but that they experienced 30% increases in brain water content at the highest ammonia concentrations. This swelling was accompanied by 4-fold increases in plasma total ammonia (TAmm) concentration, but both plasma TAmm and brain water content were restored to pre-exposure levels following depuration in ammonia-free water. The closely related, ammonia-tolerant goldfish (Carassius auratus) responded similarly to HEA (up to 3.6 mmol L(-1)), which was accompanied by 4-fold increases in brain glutamine. Subsequent administration of the glutamine synthetase inhibitor, methionine sulfoximine (MSO), reduced brain glutamine accumulation by 80% during HEA. However, MSO failed to prevent ammonia-induced increases in brain water content suggesting that glutamine may not be directly involved in initiating ammonia-induced brain swelling in fishes. Although the mechanisms of brain swelling are likely different, exposure to anoxia for 96 h caused similar, but lesser (10%) increases in brain water content in crucian carp. We conclude that brain swelling in some fishes may be a common response to increased internal ammonia or lower oxygen but further research is needed to deduce the underlying mechanisms behind such responses.

  18. Simulated diabetic ketoacidosis therapy in vitro elicits brain cell swelling via sodium-hydrogen exchange and anion transport.

    PubMed

    Rose, Keeley L; Watson, Andrew J; Drysdale, Thomas A; Cepinskas, Gediminas; Chan, Melissa; Rupar, C Anthony; Fraser, Douglas D

    2015-08-15

    A common complication of type 1 diabetes mellitus is diabetic ketoacidosis (DKA), a state of severe insulin deficiency. A potentially harmful consequence of DKA therapy in children is cerebral edema (DKA-CE); however, the mechanisms of therapy-induced DKA-CE are unknown. Our aims were to identify the DKA treatment factors and membrane mechanisms that might contribute specifically to brain cell swelling. To this end, DKA was induced in juvenile mice with the administration of the pancreatic toxins streptozocin and alloxan. Brain slices were prepared and exposed to DKA-like conditions in vitro. Cell volume changes were imaged in response to simulated DKA therapy. Our experiments showed that cell swelling was elicited with isolated DKA treatment components, including alkalinization, insulin/alkalinization, and rapid reductions in osmolality. Methyl-isobutyl-amiloride, a nonselective inhibitor of sodium-hydrogen exchangers (NHEs), reduced cell swelling in brain slices elicited with simulated DKA therapy (in vitro) and decreased brain water content in juvenile DKA mice administered insulin and rehydration therapy (in vivo). Specific pharmacological inhibition of the NHE1 isoform with cariporide also inhibited cell swelling, but only in the presence of the anion transport (AT) inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid. DKA did not alter brain NHE1 isoform expression, suggesting that the cell swelling attributed to the NHE1 was activity dependent. In conclusion, our data raise the possibility that brain cell swelling can be elicited by DKA treatment factors and that it is mediated by NHEs and/or coactivation of NHE1 and AT.

  19. Laboratory Study of Crack Development and Crack Interaction in Concrete Blocks due to Swelling of Cracking Agent

    NASA Astrophysics Data System (ADS)

    Frühwirt, Thomas; Plößer, Arne; Konietzky, Heinz

    2015-04-01

    The main focus of this work was to investigate temporary and spatial features of crack development in concrete blocks due to the action of a swelling agent. A commercial available cement-based mortar which shows heavily swelling behaviour when hydrating is used to provide inside pressure in boreholes in conrete blocks and hence serves as cracking agent. As no data for the swelling behaviour of the cracking agent were available the maximum axial swelling stress and axial free swelling strain were determined experimentally. In a first series of tests on concrete blocks the influence of an external mechanical, unidirectional stress on the development-time and orientation of cracks has been investigated for a range of loading levels. The stress state in the blocks prepared with a single borehole was determined by a superposition of internal stresses caused by swelling pressure and external mechanical loading. For a second series of tests prismatic blocks with two boreholes where prepared. This test setup allowed to realize different orientation of boreholes with respect to the uniaxial loading direction. Complementary tests were done using the cracking agent in both, only one or none of the boreholes. Different modes of crack interaction and influence of filled or unfilled boreholes have been observed. Features of crack development showed significant sensitivity to external loading. Starting even at very low load levels crack orientation was primarely determined by the direction of the external load. Temporal change in crack development due to the different load levels was insignificant and no consistent conclusion could be drawn. Crack interaction phenomena only were observed with two boreholes orientated primarely in direction of the external loading. Even in these cases crack orientation was mainly determined by the external stress field and only locally influenced by other cracks or the unfilled borehole. The work provides us with an extensive catalogue of

  20. Testicular Swelling Due to Lymphatic Filariasis after Brief Travel to Haiti

    PubMed Central

    Marcos, Luis A.; Shapley, Nathan P.; Eberhard, Mark; Epstein, Jonathan I.; Fox, LeAnne M.; Magill, Alan; Nutman, Thomas B.

    2014-01-01

    After 6 months of a trip to Haiti, a 25-year-old healthy man presented with a 6-week history of a very slow progressive intermittent bilateral testicular pain and swelling. The biopsies in both testicles revealed the presence of a dead filarial parasite. Polymerase chain reaction products of the DNA from the biopsy were shown to have a 100% identity to Wuchereria bancrofti. Despite being uncommon in travelers, this presentation of W. bancrofti highlights the possibility of acquiring W. bancrofti during short-term trips to highly endemic regions of the world (i.e., Haiti). PMID:24865674

  1. [Application of alpha-tocopherol acetate prevents swelling of brain slices during the autoblood clot action].

    PubMed

    Khama-Murad, A Kh; Mokrushin, A A; Pavlinova, L I

    2011-01-01

    The swelling of olfactory cortex slices of the hypertensive SHR rats under the long autoblood action have been studied. The influence of a preincubation of slices with vitamins E, C and D on a degree of swelling have been detected by their weighing before and after exposure to autoblood. The water-soluble form of vitamin E have exerted a substantial antiswelling action exceeding the same of vitamin D, whereas vitamin C had no any effect.

  2. Fixed negative charge and the Donnan effect: a description of the driving forces associated with brain tissue swelling and oedema

    PubMed Central

    Elkin, Benjamin S.; Shaik, Mohammed A.; Morrison, Barclay

    2010-01-01

    Cerebral oedema or brain tissue swelling is a significant complication following traumatic brain injury or stroke that can increase the intracranial pressure (ICP) and impair blood flow. Here, we have identified a potential driver of oedema: the negatively charged molecules fixed within cells. This fixed charge density (FCD), once exposed, could increase ICP through the Donnan effect. We have shown that metabolic processes and membrane integrity are required for concealing this FCD as slices of rat cortex swelled immediately (within 30 min) following dissection if treated with 2 deoxyglucose + cyanide (2DG+CN) or Triton X-100. Slices given ample oxygen and glucose, however, did not swell significantly. We also found that dead brain tissue swells and shrinks in response to changes in ionic strength of the bathing medium, which suggests that the Donnan effect is capable of pressurizing and swelling brain tissue. As predicted, a non-ionic osmolyte, 1,2 propanediol, elicited no volume change at 2000×10−3 osmoles l−1 (Osm). Swelling data were well described by triphasic mixture theory with the calculated reference state FCD similar to that measured with a 1,9 dimethylmethylene blue assay. Taken together, these data suggest that intracellular fixed charges may contribute to the driving forces responsible for brain swelling. PMID:20047940

  3. Joint swelling

    MedlinePlus

    Swelling of a joint ... Joint swelling may occur along with joint pain . The swelling may cause the joint to appear larger or abnormally shaped. Joint swelling can cause pain or stiffness. After an ...

  4. Brain Swelling and Loss of Gray and White Matter Differentiation in Human Postmortem Cases by Computed Tomography

    PubMed Central

    Shirota, Go; Gonoi, Wataru; Ishida, Masanori; Okuma, Hidemi; Shintani, Yukako; Abe, Hiroyuki; Takazawa, Yutaka; Ikemura, Masako; Fukayama, Masashi; Ohtomo, Kuni

    2015-01-01

    The purpose of this study was to evaluate the brain by postmortem computed tomography (PMCT) versus antemortem computed tomography (AMCT) using brains from the same patients. We studied 36 nontraumatic subjects who underwent AMCT, PMCT, and pathological autopsy in our hospital between April 2009 and December 2013. PMCT was performed within 20 h after death, followed by pathological autopsy including the brain. Autopsy confirmed the absence of intracranial disorders that might be related to the cause of death or might affect measurements in our study. Width of the third ventricle, width of the central sulcus, and attenuation in gray matter (GM) and white matter (WM) from the same area of the basal ganglia, centrum semiovale, and high convexity were statistically compared between AMCT and PMCT. Both the width of the third ventricle and the central sulcus were significantly shorter in PMCT than in AMCT (P < 0.0001). GM attenuation increased after death at the level of the centrum semiovale and high convexity, but the differences were not statistically significant considering the differences in attenuation among the different computed tomography scanners. WM attenuation significantly increased after death at all levels (P<0.0001). The differences were larger than the differences in scanners. GM/WM ratio of attenuation was significantly lower by PMCT than by AMCT at all levels (P<0.0001). PMCT showed an increase in WM attenuation, loss of GM–WM differentiation, and brain swelling, evidenced by a decrease in the size of ventricles and sulci. PMID:26618492

  5. [Unusual location of a brain abscess due to Listeria monocytogenes].

    PubMed

    Coste, J-F; Duval, V; Nguyen, Y; Guillard, T; Brasme, L; David, C; Strady, C; Lecuit, M; de Champs, C

    2012-10-01

    Here we report a case of sustentorial brain abscess due to Listeria monocytogenes. Blood culture and procalcitonine blood measurement were negative. L. monocytogenes was isolated from CSF after inoculation in Castañeda medium. PMID:21835558

  6. Finite Element Analysis of Brain Injury due to Head Impact

    NASA Astrophysics Data System (ADS)

    Suh, Chang Min; Kim, Sung Ho; Goldsmith, Werner

    Traumatic Brain Injury (TBI) due to head impact by external impactor was analyzed using Finite Element Method (FEM). Two-dimensiona modeling was performed according to Magnetic Resonance Imaging (MRI) data of Mongolian subject. Pressure variation in a cranium due to external impact was analyzed in order to simulate Nahum et al.'s cadaver test.6 And, analyzed results were compared with Nahum et al.'s experimental data.6 As results, stress and strain behaviors of the brain during impact were accorded with experimental data qualitatively even though there were some differences in quantitative values. In addition, they were accorded with other references about brain injury as well.

  7. A rare cause of unilateral parotid gland swelling: compensatory hypertrophy due to the aplasia of the contralateral parotid gland.

    PubMed

    Günbey, Hediye Pinar; Günbey, Emre; Tayfun, Fatma; Kaytez, Selda Kargin

    2014-05-01

    In this clinical report, 3 cases, admitted to the ears, nose, throat outpatient clinic with the complaints of unilateral swelling in the parotid region and facial asymmetry, are presented. In the etiology, contralateral parotid gland aplasia with compensatory hypertrophy and sialosis was detected. With this rare condition, clinical and radiological features of this anomaly are discussed. PMID:24799112

  8. Brain-derived neurotrophic factor inhibits osmotic swelling of rat retinal glial (Müller) and bipolar cells by activation of basic fibroblast growth factor signaling.

    PubMed

    Berk, B-A; Vogler, S; Pannicke, T; Kuhrt, H; Garcia, T B; Wiedemann, P; Reichenbach, A; Seeger, J; Bringmann, A

    2015-06-01

    Water accumulation in retinal glial (Müller) and neuronal cells resulting in cellular swelling contributes to the development of retinal edema and neurodegeneration. Intravitreal administration of neurotrophins such as brain-derived neurotrophic factor (BDNF) is known to promote survival of retinal neurons. Here, we show that exogenous BDNF inhibits the osmotic swelling of Müller cell somata induced by superfusion of rat retinal slices or freshly isolated cells with a hypoosmotic solution containing barium ions. BDNF also inhibited the osmotic swelling of bipolar cell somata in retinal slices, but failed to inhibit the osmotic soma swelling of freshly isolated bipolar cells. The inhibitory effect of BDNF on Müller cell swelling was mediated by activation of tropomyosin-related kinase B (TrkB) and transactivation of fibroblast growth factor receptors. Exogenous basic fibroblast growth factor (bFGF) fully inhibited the osmotic swelling of Müller cell somata while it partially inhibited the osmotic swelling of bipolar cell somata. Isolated Müller cells displayed immunoreactivity of truncated TrkB, but not full-length TrkB. Isolated rod bipolar cells displayed immunoreactivities of both TrkB isoforms. Data suggest that the neuroprotective effect of exogenous BDNF in the retina is in part mediated by prevention of the cytotoxic swelling of retinal glial and bipolar cells. While BDNF directly acts on Müller cells by activation of TrkB, BDNF indirectly acts on bipolar cells by inducing glial release of factors like bFGF that inhibit bipolar cell swelling.

  9. Azadirachta indica ethanolic extract protects neurons from apoptosis and mitigates brain swelling in experimental cerebral malaria

    PubMed Central

    2013-01-01

    Background Cerebral malaria is a rapidly developing encephalopathy caused by the apicomplexan parasite Plasmodium falciparum. Drugs currently in use are associated with poor outcome in an increasing number of cases and new drugs are urgently needed. The potential of the medicinal plant Azadirachta indica (Neem) for the treatment of experimental cerebral malaria was evaluated in mice. Methods Experimental cerebral malaria was induced in mice by infection with Plasmodium berghei ANKA. Infected mice were administered with Azadirachta indica ethanolic extract at doses of 300, 500, or 1000 mg/kg intraperitoneally (i.p.) in experimental groups, or with the anti-malarial drugs chloroquine (12 mg/kg, i.p.) or artemether (1.6 mg/kg, i.p.), in the positive control groups. Treatment was initiated at the onset of signs of brain involvement and pursued for five days on a daily basis. Mice brains were dissected out and processed for the study of the effects of the extract on pyramidal cells’ fate and on markers of neuroinflammation and apoptosis, in the medial temporal lobe. Results Azadirachta indica ethanolic extract mitigated neuroinflammation, decreased the severity of brain oedema, and protected pyramidal neurons from apoptosis, particularly at the highest dose used, comparable to chloroquine and artemether. Conclusions The present findings suggest that Azadirachta indica ethanolic extract has protective effects on neuronal populations in the inflamed central nervous system, and justify at least in part its use in African and Asian folk medicine and practices. PMID:23984986

  10. Mildly Reduced Brain Swelling and Improved Neurological Outcome in Aquaporin-4 Knockout Mice following Controlled Cortical Impact Brain Injury

    PubMed Central

    Uchida, Kazuyoshi; Papadopoulos, Marios C.; Zador, Zsolt; Manley, Geoffrey T.; Verkman, Alan S.

    2015-01-01

    Abstract Brain edema following traumatic brain injury (TBI) is associated with considerable morbidity and mortality. Prior indirect evidence has suggested the involvement of astrocyte water channel aquaporin-4 (AQP4) in the pathogenesis of TBI. Here, focal TBI was produced in wild type (AQP4+/+) and knockout (AQP4−/−) mice by controlled cortical impact injury (CCI) following craniotomy with dura intact (parameters: velocity 4.5 m/sec, depth 1.7 mm, dwell time 150 msec). AQP4-deficient mice showed a small but significant reduction in injury volume in the first week after CCI, with a small improvement in neurological outcome. Mechanistic studies showed reduced intracranial pressure at 6 h after CCI in AQP4−/− mice, compared with AQP4+/+ control mice (11 vs. 19 mm Hg), with reduced local brain water accumulation as assessed gravimetrically. Transmission electron microscopy showed reduced astrocyte foot-process area in AQP4−/− mice at 24 h after CCI, with greater capillary lumen area. Blood–brain barrier disruption assessed by Evans blue dye extravasation was similar in AQP4+/+ and AQP4−/− mice. We conclude that the mildly improved outcome in AQP4−/− mice following CCI results from reduced cytotoxic brain water accumulation, though concurrent cytotoxic and vasogenic mechanisms in TBI make the differences small compared to those seen in disorders where cytotoxic edema predominates. PMID:25790314

  11. Brain abscess due to Haemophilus aphrophilus: case report

    PubMed Central

    Yamashita, J.; Bone, F. J.; Hitchcock, Edward

    1972-01-01

    A temporal lobe abscess due to H. aphrophilus occurred in a child of 11 years, and was successfully treated by aspiration, chemotherapy, and excision of the abscess wall. The organism is an unusual cause of brain abscess and this is believed to be the first reported case in Britain. PMID:4647862

  12. Scrotal swelling

    MedlinePlus

    ... determine whether you need any tests. Your health care provider may prescribe antibiotics and pain medications, or recommend surgery. A scrotal ultrasound may be done to find where the swelling is occurring.

  13. Postoperative Submandibular Gland Swelling following Craniotomy under General Anesthesia.

    PubMed

    Nakanishi, Haruka; Tono, Tetsuya; Ibusuki, Shoichiro

    2015-01-01

    Objective. Reporting of a rare case of postoperative submandibular gland swelling following craniotomy. Case Report. A 33-year-old male underwent resection for a brain tumor under general anesthesia. The tumor was resected via a retrosigmoid suboccipital approach and the patient was placed in a lateral position with his face down and turned to the right. Slight swelling of the right submandibular gland was observed just after the surgery. Seven hours after surgery, edematous change around the submandibular gland worsened and he required emergent reintubation due to airway compromise. The cause of submandibular gland swelling seemed to be an obstruction of the salivary duct due to surgical positioning. Conclusion. Once submandibular swelling and edematous change around the submandibular gland occur, they can worsen and compromise the air way within several hours after operation. Adequate precaution must be taken for any predisposing skull-base surgery that requires strong cervical rotation and flexion. PMID:26697254

  14. Postoperative Submandibular Gland Swelling following Craniotomy under General Anesthesia

    PubMed Central

    Nakanishi, Haruka; Tono, Tetsuya; Ibusuki, Shoichiro

    2015-01-01

    Objective. Reporting of a rare case of postoperative submandibular gland swelling following craniotomy. Case Report. A 33-year-old male underwent resection for a brain tumor under general anesthesia. The tumor was resected via a retrosigmoid suboccipital approach and the patient was placed in a lateral position with his face down and turned to the right. Slight swelling of the right submandibular gland was observed just after the surgery. Seven hours after surgery, edematous change around the submandibular gland worsened and he required emergent reintubation due to airway compromise. The cause of submandibular gland swelling seemed to be an obstruction of the salivary duct due to surgical positioning. Conclusion. Once submandibular swelling and edematous change around the submandibular gland occur, they can worsen and compromise the air way within several hours after operation. Adequate precaution must be taken for any predisposing skull-base surgery that requires strong cervical rotation and flexion. PMID:26697254

  15. Low-molecular-mass peptides from the venom of the Amazonian viper Bothrops atrox protect against brain mitochondrial swelling in rat: potential for neuroprotection.

    PubMed

    Martins, N M; Ferreira, D A S; Carvalho Rodrigues, M A; Cintra, A C O; Santos, N A G; Sampaio, S V; Santos, A C

    2010-08-01

    The neurodegenerative diseases are important causes of morbidity and mortality in Western countries. Common mechanisms of toxicity involving mitochondrial damage have been suggested; however, a definitive treatment has not yet been found. Therefore, there has been great interest in the development of mitochondria-targeted protective compounds for the treatment of neuropathies. Animal toxins represent a promising source of new molecules with neuroprotective activity and potential to originate new drugs. We present here the effects of a low-molecular-mass peptides fraction (Ba-V) from Bothrops atrox snake venom, on rat brain mitochondrial function. Ba-V did not induce the mitochondrial swelling and moreover, was as effective as cyclosporin A (CsA) to inhibit the calcium/phosphate-induced swelling, which indicates its potential to prevent the mitochondrial permeability transition (MPT). The membrane electrochemical potential, the oxygen consumption during states-3 and -4 respirations as well as the respiratory control ratio (RCR) were not affected by Ba-V. Additionally, Ba-V did not induce reactive oxygen species (ROS) generation. Interestingly, Ba-V did not protect against the generation of ROS induced by t-BOH, which suggests a protection mechanism other than ROS scavenging. Given the important role of the mitochondrial damage and, more specifically, of MPT, in the development of neuropathies, Ba-V might be useful in the future strategies for the treatment of these diseases. PMID:20338188

  16. Facial swelling

    MedlinePlus

    ... transfusion reaction Cellulitis Conjunctivitis (inflammation of the eye) Drug reactions, including those due to aspirin, penicillin, sulfa, glucocorticoids, and others Head, nose, or jaw surgery ...

  17. Hotspot swells revisited

    NASA Astrophysics Data System (ADS)

    King, Scott D.; Adam, Claudia

    2014-10-01

    The first attempts to quantify the width and height of hotspot swells were made more than 30 years ago. Since that time, topography, ocean-floor age, and sediment thickness datasets have improved considerably. Swell heights and widths have been used to estimate the heat flow from the core-mantle boundary, constrain numerical models of plumes, and as an indicator of the origin of hotspots. In this paper, we repeat the analysis of swell geometry and buoyancy flux for 54 hotspots, including the 37 considered by Sleep (1990) and the 49 considered by Courtillot et al. (2003), using the latest and most accurate data. We are able to calculate swell geometry for a number of hotspots that Sleep was only able to estimate by comparison with other swells. We find that in spite of the increased resolution in global bathymetry models there is significant uncertainty in our calculation of buoyancy fluxes due to differences in our measurement of the swells’ width and height, the integration method (volume integration or cross-sectional area), and the variations of the plate velocities between HS2-Nuvel1a (Gripp and Gordon, 1990) and HS3-Nuvel1a (Gripp and Gordon, 2002). We also note that the buoyancy flux for Pacific hotspots is in general larger than for Eurasian, North American, African and Antarctic hotspots. Considering that buoyancy flux is linearly related to plate velocity, we speculate that either the calculation of buoyancy flux using plate velocity over-estimates the actual vertical flow of material from the deep mantle or that convection in the Pacific hemisphere is more vigorous than the Atlantic hemisphere.

  18. Foot, leg, and ankle swelling

    MedlinePlus

    Swelling of the ankles - feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... Painless swelling may affect both legs and may include the calves or ... of gravity makes the swelling most noticeable in the lower ...

  19. Was Julius Caesar's epilepsy due to a brain tumor?

    PubMed

    Gomez, J G; Kotler, J A; Long, J B

    1995-03-01

    Two thousand thirty-eight years later, in the setting of a similar care presentation, a physician would take a detailed history and perform a clinical and neurological examination. A preliminary diagnosis would be entertained and followed by electroencephalography and magnetic resonance of the brain with and without paramagnetic contrast for diagnostic confirmation. The proper medical or surgical treatment would then be instituted. A reconstruction of the clinical history of Julius Caesar (100-44 B.C.) has been attempted from available information from literature. Although a definite conclusion obviously cannot be made, a differential diagnosis provided with a tentative hypothesis is presented. The patient had late onset of seizures in the last two years of his life, headaches, personality changes. Upon reexamination of existing Julius Caesar iconography, busts, statues and minted coins no skull deformities have been noted. Identification of a skull deformity as described by Suetonius would have confirmed the suspicion of meningioma involving the convexity of the cerebral hemispheres. Meningioma or slow-growing supratentorial glioma may well have been responsible for this man's illness. Who knows how the course of history might have been changed... Probably not at all. PMID:7738524

  20. Visual hallucinations of autobiographic memory and asomatognosia: a case of epilepsy due to brain cysticercosis.

    PubMed

    Orjuela-Rojas, Juan Manuel; Ramírez-Bermúdez, Jesús; Martínez-Juárez, Iris E; Kerik, Nora Estela; Diaz Meneses, Iván; Pérez-Gay, Fernanda Juárez

    2015-01-01

    The current study describes the case of a woman with symptomatic epilepsy due to brain cysticercosis acquired during childhood. During her adolescence, she developed seizures characterized by metamorphopsia, hallucinations of autobiographic memory and, finally, asomatognosia. Magnetic brain imaging showed a calcified lesion in the right occipitotemporal cortex, and positron emission tomography imaging confirmed the presence of interictal hypometabolism in two regions: the right parietal cortex and the right lateral and posterior temporal cortex. We discuss the link between these brain areas and the symptoms described under the concepts of epileptogenic lesion, epileptogenic zone, functional deficit zone, and symptomatogenic zone.

  1. A thoracic mechanism of mild traumatic brain injury due to blast pressure waves.

    PubMed

    Courtney, A C; Courtney, M W

    2009-01-01

    The mechanisms by which blast pressure waves cause mild-to-moderate traumatic brain injury (mTBI) are an open question. Possibilities include acceleration of the head, direct passage of the blast wave via the cranium, and propagation of the blast wave to the brain via a thoracic mechanism. The hypothesis that the blast pressure wave reaches the brain via a thoracic mechanism is considered in light of ballistic and blast pressure wave research. Ballistic pressure waves, caused by penetrating ballistic projectiles or ballistic impacts to body armor, can only reach the brain via an internal mechanism and have been shown to cause cerebral effects. Similar effects have been documented when a blast pressure wave has been applied to the whole body or focused on the thorax in animal models. While vagotomy reduces apnea and bradycardia due to ballistic or blast pressure waves, it does not eliminate neural damage in the brain, suggesting that the pressure wave directly affects the brain cells via a thoracic mechanism. An experiment is proposed which isolates the thoracic mechanism from cranial mechanisms of mTBI due to blast wave exposure. Results have implications for evaluating risk of mTBI due to blast exposure and for developing effective protection. PMID:18829180

  2. Predicting brain tissue deformation around an implantable electrode due to dynamic micromotion

    NASA Astrophysics Data System (ADS)

    Polanco, Michael; Yoon, Hargsoon; Lee, Keejoo; Bawab, Sebastian

    2012-04-01

    Brain cells located adjacent to an implantable electrode are susceptible to both insertion and mechanical damage due to micromotion as the tissue undergoes cyclic periods of pulsation and breathing. The brain cells inevitably interface with electrodes that are typically much lighter and stiffer in comparison. As a result, the brain's high sensitivity to deformation poses a great challenge in designing a neuron probe that is durable throughout time, as mechanical damage in the brain can reduce the usefulness of the electrode. A number of electrode design parameters need to be examined to determine how the brain's high susceptibility to deformation can be minimized, such as material properties and geometry. Objectively, a neuron probe may need to be designed such that it can conform to motion of the brain while electrical functionality is maintained during deformation. To better understand the design enhancements needed for the neuron probe, a series of dynamic simulations are conducted which represent the motion the brain is expected to undergo over time. This motion will, in turn, influence the motion of the neuron probe throughout time. Of interest is how the brain tissue deformation near the interface of the neuron probe will be affected by micromotion of the probe. The nonlinear transient explicit finite element code LS-DYNA is used to carry out the analyses.

  3. [Penetrating brain injury due to a large asbestos fragment treated by decompressive craniectomy: case report].

    PubMed

    Andrade, Gustavo Cardoso de; Silveira, Roberto Leal; Arantes, Aluízio Augusto; Fonseca Filho, Gilberto Almeida; Pinheiro, Nilson

    2004-12-01

    We report the case of a 22-year-old man victim of penetrating brain injury due to a 15 x 12 asbestos fragment and a successfully treatment via decompressive craniectomy. Unlike gunshot wounds to the head, penetrating brain injury from low energy objects are unusual. Most cases reported involve cranio-orbitary injuries as well as self inflicted lesions in mentally ill patients. The reported case is noteworthy due to the large dimensions of the foreign body, the treatment via decompressive craniectomy and the good patient functional outcome.

  4. Relationship between light scattering and absorption due to cytochrome c oxidase reduction during loss of tissue viability in brains of rats

    NASA Astrophysics Data System (ADS)

    Kawauchi, Satoko; Sato, Shunichi; Ooigawa, Hidetoshi; Nawashiro, Hiroshi; Ishihara, Miya; Kikuchi, Makoto

    2008-02-01

    We performed simultaneous measurement of light scattering and absorption due to reduction of cytochrome c oxidase as intrinsic optical signals that are related to morphological characteristics and energy metabolism, respectively, for rat brains after oxygen/glucose deprivation by saline infusion. To detect change in light scattering, we determined the wavelength that was the most insensitive to change in light absorption due to the reduction of cytochrome c oxidase on the basis of multiwavelength analysis of diffuse reflectance data set for each rat. Then the relationships between scattering signal and absorption signals related to the reductions of heme aa 3 (605 nm) and CuA (830 nm) in cytochrome c oxidase were examined. Measurements showed that after starting saline infusion, the reduction of heme aa 3 started first; thereafter triphasic, large scattering change occurred (200-300 s), during which the reduction of CuA started. Despite such complex behaviors of IOSs, almost linear correlations were seen between the scattering signal and the heme aa 3-related absorption signal, while a relatively large animal-to-animal variation was observed in the correlation between the scattering signal and CuA-related absorption signal. Transmission electron microscopic observation revealed that dendritic swelling and mitochondrial deformation occurred in the cortical surface tissue after the triphasic scattering change. These results suggest that mitochondrial energy failure accompanies morphological alteration in the brain tissue and results in change in light scattering; light scattering will become an important indicator of tissue viability in brain.

  5. Approximation error method can reduce artifacts due to scalp blood flow in optical brain activation imaging

    NASA Astrophysics Data System (ADS)

    Heiskala, Juha; Kolehmainen, Ville; Tarvainen, Tanja; Kaipio, Jari. P.; Arridge, Simon R.

    2012-09-01

    Diffuse optical tomography can image the hemodynamic response to an activation in the human brain by measuring changes in optical absorption of near-infrared light. Since optodes placed on the scalp are used, the measurements are very sensitive to changes in optical attenuation in the scalp, making optical brain activation imaging susceptible to artifacts due to effects of systemic circulation and local circulation of the scalp. We propose to use the Bayesian approximation error approach to reduce these artifacts. The feasibility of the approach is evaluated using simulated brain activations. When a localized cortical activation occurs simultaneously with changes in the scalp blood flow, these changes can mask the cortical activity causing spurious artifacts. We show that the proposed approach is able to recover from these artifacts even when the nominal tissue properties are not well known.

  6. A rare case of multilocus brain abscess due to Entamoeba histolytica infection in a child.

    PubMed

    Tamer, Gülden S; Öncel, Selim; Gökbulut, Sevil; Arisoy, Emin S

    2015-03-01

    Brain abscess due to Entamoeba histolytica (E. histolytica) may pose a diagnostic problem or a therapeutic challenge, as evidenced by the paucity of papers reporting complete recovery after treatment. An 11-year-old girl presented with progressive drowsiness, diminished movements of the left upper limb, and swallowing problems. Cranial MRI showed multiple, contrast-dense masses with fluid content. She was started on meropenem. Surgical drainage was performed. No bacterial or fungal growth was observed in drainage samples. Entamoeba histolytica trophozoites were detected in the tissue sample. Intravenous metronidazole was started and continued for 6 weeks, at the end of which abscesses were found and to have shrunk considerably. Intravenous therapy was switched to oral metronidazole, which was continued for 2 weeks. She regained all her preexisting abilities. Multiple brain abscesses due to E. histolytica is a very rare occurrence, and histopathologic evaluation is important in diagnosis. PMID:25737180

  7. Biomechanical assessment of brain dynamic responses due to blast pressure waves.

    PubMed

    Chafi, M S; Karami, G; Ziejewski, M

    2010-02-01

    stress and maximum principal strain to predict the brain injury, the research provides an assessment of the brain responses to different amounts of over-pressure. The research also demonstrates the ability to predict the ICP, as well as the stress and strain within the brain, due to such an event. The research cannot identify, however, the specific levels of ICP, stress and strain that necessarily lead to traumatic brain injury (TBI) because there is no access to experimental data regarding head-blast interactions. PMID:19806456

  8. Shales and swelling soils

    NASA Astrophysics Data System (ADS)

    Franklin, J. A.; Dimillio, A. F.; Strohm, W. E., Jr.; Vandre, B. C.; Anderson, L. R.

    The thirteen (13) papers in this report deal with the following areas: a shale rating system and tentative applications to shale performance; technical guidelines for the design and construction of shale embankments; stability of waste shale embankments; dynamic response of raw and stabilized Oklahoma shales; laboratory studies of the stabilization of nondurable shales; swelling shale and collapsing soil; development of a laboratory compaction degradation test for shales; soil section approach for evaluation of swelling potential soil moisture properties of subgrade soils; volume changes in compacted clays and shales on saturation; characterization of expansive soils; pavement roughness on expansive clays; and deep vertical fabric moisture barriers in swelling soils.

  9. Brain radiation - discharge

    MedlinePlus

    Radiation - brain - discharge; Cancer-brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

  10. Electromagnetic power absorption and temperature changes due to brain machine interface operation.

    PubMed

    Ibrahim, Tamer S; Abraham, Doney; Rennaker, Robert L

    2007-05-01

    To fully understand neural function, chronic neural recordings must be made simultaneously from 10s or 100s of neurons. To accomplish this goal, several groups are developing brain machine interfaces. For these devices to be viable for chronic human use, it is likely that they will need to be operated and powered externally via a radiofrequency (RF) source. However, RF exposure can result in tissue heating and is regulated by the FDA/FCC. This paper provides an initial estimate of the amount of tissue heating and specific absorption rate (SAR) associated with the operation of a brain-machine interface (BMI). The operation of a brain machine interface was evaluated in an 18-tissue anatomically detailed human head mesh using simulations of electromagnetics and bio-heat phenomena. The simulations were conducted with a single chip, as well as with eight chips, placed on the surface of the human brain and each powered at four frequencies (13.6 MHz, 1.0 GHz, 2.4 GHz, and 5.8 GHz). The simulated chips consist of a wire antenna on a silicon chip covered by a Teflon dura patch. SAR values were calculated using the finite-difference time-domain method and used to predict peak temperature changes caused by electromagnetic absorption in the head using two-dimensional bio-heat equation. Results due to SAR alone show increased heating at higher frequencies, with a peak temperature change at 5.8 GHz of approximately 0.018 degrees C in the single-chip configuration and 0.06 degrees C in the eight-chip configuration with 10 mW of power absorption (in the human head) per chip. In addition, temperature elevations due to power dissipation in the chip(s) were studied. Results show that for the neural tissue, maximum temperature rises of 3.34 degrees C in the single-chip configuration and 7.72 degrees C in the eight-chip configuration were observed for 10 mW dissipation in each chip. Finally, the maximum power dissipation allowable in each chip before a 1.0 degrees C temperature

  11. Meningoencephalitis and brain abscess due to a free-living amoeba.

    PubMed

    Duma, R J; Helwig, W B; Martinez, A J

    1978-04-01

    A 47-year-old diabetic woman developed fatal meningoencephalitis due to a free-living amoeba. The responsible organism appeared to be neither Naegleria nor Acanthamoeba-Hartmannella. Both acute and chronic (granulomatous) inflammatory reactions of the brain were present, and both cysts and trophozoite forms were readily visualized. The latest classification and methods of identification of such amoebae are reviewed and their threat to public health underscored. It should be realized that a variety of free-living amoebae exist in nature, which potentially can produce meningoencephalitis in humans, and that none of these organisms should be labeled or considered as "avirulent" or "nonpathogenic" until proved otherwise. PMID:637425

  12. Brain abscess due to Cladophialophora bantiana: a review of 124 cases.

    PubMed

    Chakrabarti, Arunaloke; Kaur, Harsimran; Rudramurthy, Shivaprakash M; Appannanavar, Suma B; Patel, Atul; Mukherjee, Kanchan K; Ghosh, Anup; Ray, Ujjwayini

    2016-02-01

    Brain abscess caused by Cladophialophora bantiana is a rare disease associated with high mortality due to delay in diagnosis and absence of standardized therapy. We reviewed 124 culture proven C. bantiana brain abscess cases; 103 cases published in English literature during 1952 through 2014 and 21 unpublished cases from our reference center. The majority (57.3%) of the patients was from Asian countries especially from India (62/124, 50%). The diagnosis of the cases was delayed with mean duration 115 days after developing symptoms. The disease was nearly equally distributed in immunocompetent and immunosuppressed hosts but associated with significantly higher mortality (77.1%) in later group. Complete excision of brain lesion in immunocompetent host led to significantly better survival (43.7%). Though all commercially available antifungal drugs have been used in these patients, amphotericin B deoxycholate or lipid preparations were most commonly (62.83%) prescribed agent. None of the drugs used was found to be independently associated with improved outcome. In vitro antifungal susceptibility testing of 13 isolates of our center, demonstrated good activity to voriconazole, posaconazole, and itraconazole, but these triazoles were prescribed in only 29.2% patients. Increased awareness with early suspicion of the disease, and aggressive medical and surgical approach in treating these patients may improve the outcome. PMID:26483430

  13. Brain abscess due to Cladophialophora bantiana: a review of 124 cases.

    PubMed

    Chakrabarti, Arunaloke; Kaur, Harsimran; Rudramurthy, Shivaprakash M; Appannanavar, Suma B; Patel, Atul; Mukherjee, Kanchan K; Ghosh, Anup; Ray, Ujjwayini

    2016-02-01

    Brain abscess caused by Cladophialophora bantiana is a rare disease associated with high mortality due to delay in diagnosis and absence of standardized therapy. We reviewed 124 culture proven C. bantiana brain abscess cases; 103 cases published in English literature during 1952 through 2014 and 21 unpublished cases from our reference center. The majority (57.3%) of the patients was from Asian countries especially from India (62/124, 50%). The diagnosis of the cases was delayed with mean duration 115 days after developing symptoms. The disease was nearly equally distributed in immunocompetent and immunosuppressed hosts but associated with significantly higher mortality (77.1%) in later group. Complete excision of brain lesion in immunocompetent host led to significantly better survival (43.7%). Though all commercially available antifungal drugs have been used in these patients, amphotericin B deoxycholate or lipid preparations were most commonly (62.83%) prescribed agent. None of the drugs used was found to be independently associated with improved outcome. In vitro antifungal susceptibility testing of 13 isolates of our center, demonstrated good activity to voriconazole, posaconazole, and itraconazole, but these triazoles were prescribed in only 29.2% patients. Increased awareness with early suspicion of the disease, and aggressive medical and surgical approach in treating these patients may improve the outcome.

  14. Personality Change Due to Traumatic Brain Injury in Children and Adolescents: Neurocognitive Correlates.

    PubMed

    Max, Jeffrey E; Wilde, Elisabeth A; Bigler, Erin D; Hanten, Gerri; Dennis, Maureen; Schachar, Russell J; Saunders, Ann E; Ewing-Cobbs, Linda; Chapman, Sandra B; Thompson, Wesley K; Yang, Tony T; Levin, Harvey S

    2015-01-01

    Personality change due to traumatic brain injury (PC) in children is an important psychiatric complication of injury and is a form of severe affective dysregulation. This study aimed to examine neurocognitive correlates of PC. The sample included 177 children 5-14 years old with traumatic brain injury who were enrolled from consecutive admissions to five trauma centers. Patients were followed up prospectively at baseline and at 6 months, and they were assessed with semistructured psychiatric interviews. Injury severity, socioeconomic status, and neurocognitive function (measures of attention, processing speed, verbal memory, IQ, verbal working memory, executive function, naming/reading, expressive language, motor speed, and motor inhibition) were assessed with standardized instruments. Unremitted PC was present in 26 (18%) of 141 participants assessed at 6 months postinjury. Attention, processing speed, verbal memory, IQ, and executive function were significantly associated with PC even after socioeconomic status, injury severity, and preinjury attention deficit hyperactivity disorder were controlled. These findings are a first step in characterizing concomitant cognitive impairments associated with PC. The results have implications beyond brain injury to potentially elucidate the neurocognitive symptom complex associated with mood instability regardless of etiology. PMID:26185905

  15. Personality Change due to Traumatic Brain Injury in Children and Adolescents: Neurocognitive Correlates

    PubMed Central

    Wilde, Elisabeth A.; Bigler, Erin D.; Hanten, Gerri; Dennis, Maureen; Schachar, Russell J.; Saunders, Ann E.; Ewing-Cobbs, Linda; Chapman, Sandra B.; Thompson, Wesley K.; Yang, Tony T.; Levin, Harvey S.

    2015-01-01

    Personality Change due to traumatic brain injury (PC) in children is an important psychiatric complication of injury and is a form of severe affective dysregulation. The aim of the study was to examine neurocognitive correlates of PC. The sample included children (n=177) aged 5-14 years with traumatic brain injury from consecutive admissions to 5 trauma centers were followed prospectively at baseline and 6 months with semi-structured psychiatric interviews. Injury severity, socioeconomic status, and neurocognitive function (measures of attention, processing speed, verbal memory, IQ, verbal working memory, executive function, naming/reading, expressive language, motor speed, and motor inhibition) were assessed with standardized instruments. Unremitted PC was present in 26/141 (18%) participants assessed at 6 months post-injury. Attention, processing speed, verbal memory, IQ, and executive function, were significantly associated (p < .05) with PC even after socioeconomic status, injury severity, and pre-injury attention-deficit/hyperactivity disorder were controlled. These findings are a first step in characterizing concomitant cognitive impairments associated with PC. The results have implications beyond brain injury to potentially elucidate the neurocognitive symptom complex associated with mood instability regardless of etiology. PMID:26185905

  16. Personality Change Due to Traumatic Brain Injury in Children and Adolescents: Neurocognitive Correlates.

    PubMed

    Max, Jeffrey E; Wilde, Elisabeth A; Bigler, Erin D; Hanten, Gerri; Dennis, Maureen; Schachar, Russell J; Saunders, Ann E; Ewing-Cobbs, Linda; Chapman, Sandra B; Thompson, Wesley K; Yang, Tony T; Levin, Harvey S

    2015-01-01

    Personality change due to traumatic brain injury (PC) in children is an important psychiatric complication of injury and is a form of severe affective dysregulation. This study aimed to examine neurocognitive correlates of PC. The sample included 177 children 5-14 years old with traumatic brain injury who were enrolled from consecutive admissions to five trauma centers. Patients were followed up prospectively at baseline and at 6 months, and they were assessed with semistructured psychiatric interviews. Injury severity, socioeconomic status, and neurocognitive function (measures of attention, processing speed, verbal memory, IQ, verbal working memory, executive function, naming/reading, expressive language, motor speed, and motor inhibition) were assessed with standardized instruments. Unremitted PC was present in 26 (18%) of 141 participants assessed at 6 months postinjury. Attention, processing speed, verbal memory, IQ, and executive function were significantly associated with PC even after socioeconomic status, injury severity, and preinjury attention deficit hyperactivity disorder were controlled. These findings are a first step in characterizing concomitant cognitive impairments associated with PC. The results have implications beyond brain injury to potentially elucidate the neurocognitive symptom complex associated with mood instability regardless of etiology.

  17. [A case of a penetrating brain injury due to an explosion of a construction machine].

    PubMed

    Ibayashi, Kenji; Tsutsumi, Kazuo; Yoshikawa, Gakushi; Uno, Takeshi; Shimada, Shiko; Kawashima, Mariko; Koizumi, Satoshi; Ochiai, Yushi

    2012-05-01

    Penetrating brain injury caused by a high speed projectile is rather rare in Japan, known for its strict gun-control laws. We report a case of a 55-year-old male, who was transferred to our hospital with a foreign body in the brain due to penetrating head injury, which was caused by an explosion of a construction machine. Neurological examination demonstrated severe motor aphagia with no apparent motor paresis. The patient had a scalp laceration on his left forehead with exposed cerebral tissue and CSF leakage. Head CT scan and plain skull X-ray revealed a 20 mm×25 mm bolt which had penetrated due to the explosion of the machine. The anterior wall of the left frontal sinus was fractured resulting in dural laceration, and scattered bone fragments were seen along the trajectory of the bolt. Digital subtraction angiography showed no significant vascular injuries including superior sagittal sinus. We performed open surgery, and successfully removed the bolt along with the damaged frontal lobe. The patient had no infection or seizure after the surgery, and was transferred for further rehabilitation therapy. We performed a cosmetic cranioplasty six months later. Surgical debridement of the damaged cerebral tissue along the trajectory led to successful removal of the bolt with no further neurological deficit. PMID:22538284

  18. Brain ultrasonographic findings of late-onset circulatory dysfunction due to adrenal insufficiency in preterm infants

    PubMed Central

    2016-01-01

    Purpose: The aim of this study was to characterize the brain ultrasonographic findings of late-onset circulatory dysfunction (LCD) due to adrenal insufficiency (AI) in preterm infants. Methods: Among the 257 preterm infants born at <33 weeks of gestation between December 2009 and February 2014 at our institution, 35 preterm infants were diagnosed with AI. Brain ultrasonographic findings were retrospectively analyzed before and after LCD in 14 preterm infants, after exclusion of the other 21 infants with AI due to the following causes: death (n=2), early AI (n=5), sepsis (n=1), and patent ductus arteriosus (n=13). Results: Fourteen of 257 infants (5.4%) were diagnosed with LCD due to AI. The age at LCD was a median of 18.5 days (range, 9 to 32 days). The last ultrasonographic findings before LCD occurred showed grade 1 periventricular echogenicity (PVE) in all 14 patients and germinal matrix hemorrhage (GMH) with focal cystic change in one patient. Ultrasonographic findings after LCD demonstrated no significant change in grade 1 PVE and no new lesions in eight (57%), grade 1 PVE with newly appearing GMH in three (21%), and increased PVE in three (21%) infants. Five infants (36%) showed new development (n=4) or increased size (n=1) of GMH. Two of three infants (14%) with increased PVE developed cystic periventricular leukomalacia (PVL) and rapid progression to macrocystic encephalomalacia. Conclusion: LCD due to AI may be associated with the late development of GMH, increased PVE after LCD, and cystic PVL with rapid progression to macrocystic encephalomalacia. PMID:27156563

  19. Predictors of Personality Change Due to Traumatic Brain Injury in Children and Adolescents in the First Six Months after Injury.

    ERIC Educational Resources Information Center

    Max, Jeffrey E.; Levin, Harvey S.; Landis, Julie; Schachar, Russell; Saunders, Ann; Ewing-Cobbs, Linda; Chapman, Sandra B.; Dennis, Maureen

    2005-01-01

    Objective: To assess the phenomenology and predictive factors of personality change due to traumatic brain injury. Method: Children (N = 177), aged 5 to 14 years with traumatic brain injury from consecutive admissions to five trauma centers, were followed prospectively at baseline and 6 months with semistructured psychiatric interviews. Injury…

  20. Intermittent facial swelling

    PubMed Central

    Pope, Charlie; Gopala Pillai, Suresh Kumar

    2014-01-01

    Intermittent facial swelling is an unusual presentation in the emergency department. The differential diagnosis may range from a variety of causes. Most common differential diagnosis is angio-oedema. However, more serious presentations such as superior venacaval obstruction must not be ignored. This case report presents a patient who was investigated in the hospital for 2 weeks (2 admissions) with intermittent facial swelling. He presented to the emergency department (3rd admission) and was diagnosed to have superior venacaval obstruction secondary to metastatic bronchogenic carcinoma. He underwent emergency endovascular stenting; however, he died within a few weeks. PMID:25326556

  1. SYNERESIS AND SWELLING OF GELATIN.

    PubMed

    Kunitz, M

    1928-11-20

    1. When solid blocks of isoelectric gelatin are placed in cold distilled water or dilute buffer of pH 4.7, only those of a gelatin content of more than 10 per cent swell, while those of a lower gelatin content not only do not swell but actually lose water. 2. The final quantity of water lost by blocks of dilute gelatin is the same whether the block is immersed in a large volume of water or whether syneresis has been initiated in the gel through mechanical forces such as shaking, pressure, etc., even in the absence of any outside liquid, thus showing that syneresis is identical with the process of negative swelling of dilute gels when placed in cold water, and may be used as a convenient term for it. 3. Acid- or alkali-containing gels give rise to greater syneresis than isoelectric gels, after the acid or alkali has been removed by dialysis. 4. Salt-containing gels show greater syneresis than salt-free gels of the same pH, after the salt has been washed away. 5. The acid and alkali and also the salt effect on syneresis of gels disappears at a gelatin concentration above 8 per cent. 6. The striking similarity in the behavior of gels with respect to syneresis and of gelatin solutions with respect to viscosity suggests the probability that both are due to the same mechanism, namely the mechanism of hydration of the micellae in gelatin by means of osmosis as brought about either by diffusible ions, as in the presence of acid or alkali, or by the soluble gelatin present in the micellae. The greater the pressures that caused swelling of the micellae while the gelatin was in the sol state, the greater is the loss of water from the gels when the pressures are removed. 7. A quantitative study of the loss of water by dilute gels of various gelatin content shows that the same laws which have been found by Northrop to hold for the swelling of gels of high concentrations apply also to the process of losing water by dilute gels, i.e. to the process of syneresis. The general

  2. Swelling transition of a clay induced by heating.

    PubMed

    Hansen, E L; Hemmen, H; Fonseca, D M; Coutant, C; Knudsen, K D; Plivelic, T S; Bonn, D; Fossum, J O

    2012-01-01

    Clays are of paramount importance for soil stability, but also in applications ranging from oil recovery to composites and hydrogels. Generically, clays are divided into two subclasses: macroscopically swelling, 'active' clays that have the capacity for taking up large amounts of water to form stable gels, and 'passive' or non-swelling clays; the former stabilize soils whereas the latter are known to lead to landslides. However, it has been unclear so far what mechanisms underlie clay swelling. Here, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. We propose a simple description of the swelling transition; while net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other in stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling.

  3. Swelling transition of a clay induced by heating.

    PubMed

    Hansen, E L; Hemmen, H; Fonseca, D M; Coutant, C; Knudsen, K D; Plivelic, T S; Bonn, D; Fossum, J O

    2012-01-01

    Clays are of paramount importance for soil stability, but also in applications ranging from oil recovery to composites and hydrogels. Generically, clays are divided into two subclasses: macroscopically swelling, 'active' clays that have the capacity for taking up large amounts of water to form stable gels, and 'passive' or non-swelling clays; the former stabilize soils whereas the latter are known to lead to landslides. However, it has been unclear so far what mechanisms underlie clay swelling. Here, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. We propose a simple description of the swelling transition; while net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other in stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling. PMID:22943004

  4. Mitosis is swell.

    PubMed

    Zatulovskiy, Evgeny; Skotheim, Jan M

    2015-11-23

    Cell volume and dry mass are typically correlated. However, in this issue, Zlotek-Zlotkiewicz et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505056) and Son et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505058) use new live-cell techniques to show that entry to mitosis coincides with rapid cell swelling, which is reversed before division.

  5. Mitosis is swell

    PubMed Central

    Zatulovskiy, Evgeny

    2015-01-01

    Cell volume and dry mass are typically correlated. However, in this issue, Zlotek-Zlotkiewicz et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505056) and Son et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505058) use new live-cell techniques to show that entry to mitosis coincides with rapid cell swelling, which is reversed before division. PMID:26598610

  6. Post-mortem Findings in Huntington’s Deep Brain Stimulation: A Moving Target Due to Atrophy

    PubMed Central

    Vedam-Mai, Vinata; Martinez-Ramirez, Daniel; Hilliard, Justin D.; Carbunaru, Samuel; Yachnis, Anthony T.; Bloom, Joshua; Keeling, Peyton; Awe, Lisa; Foote, Kelly D.; Okun, Michael S.

    2016-01-01

    Background Deep brain stimulation (DBS) has been shown to be effective for Parkinson’s disease, essential tremor, and primary dystonia. However, mixed results have been reported in Huntington’s disease (HD). Case Report A single case of HD DBS was identified from the University of Florida DBS Brain Tissue Network. The clinical presentation, evolution, surgical planning, DBS parameters, clinical outcomes, and brain pathological changes are summarized. Discussion This case of HD DBS revealed that chorea may improve and be sustained. Minimal histopathological changes were noted around the DBS leads. Severe atrophy due to HD likely changed the DBS lead position relative to the internal capsule. PMID:27127722

  7. Irradiation creep relaxation of void swelling-driven stresses

    NASA Astrophysics Data System (ADS)

    Hall, M. M.

    2013-01-01

    Swelling-driven-creep test specimens are used to measure the compressive stresses that develop due to constraint of irradiation void swelling. These specimens use a previously non-irradiated 20% CW Type 316 stainless steel holder to axially restrain two Type 304 stainless steel tubular specimens that were previously irradiated in the US Experimental Breeder Reactor (EBR-II) at 490 °C. One specimen was previously irradiated to fluence levels in the void nucleation regime (9 dpa) and the other in the quasi-steady void growth regime (28 dpa). A lift-off compliance measurement technique was used post-irradiation to determine compressive stresses developed during reirradiation of the two specimen assemblies in Row 7 of EBR-II at temperatures of 547 °C and 504 °C, respectively, to additional damage levels each of about 5 dpa. Results obtained on the higher fluence swelling-driven-creep specimen show that compressive stress due to constraint of swelling retards void swelling to a degree that is consistent with active load uniaxial compression specimens that were irradiated as part of a previously reported multiaxial in-reactor creep experiment. Swelling results obtained on the lower fluence swelling-driven creep specimen show a much larger effect of compressive stress in reducing swelling, demonstrating that the larger effect of stress on swelling is on void nucleation as compared to void growth. Test results are analyzed using a recently proposed multiaxial creep-swelling model.

  8. Postoperative pectoral swelling after shoulder arthroscopy

    PubMed Central

    ERCIN, ERSIN; BILGILI, MUSTAFA GOKHAN; ONES, HALIL NADIR; KURAL, CEMAL

    2015-01-01

    Fluid extravasation is possibly the most common complication of shoulder arthroscopy. Shoulder arthroscopy can lead to major increases in the compartment pressure of adjacent muscles and this phenomenon is significant when an infusion pump is used. This article describes a case of pectoral swelling due to fluid extravasation after shoulder arthroscopy. A 24-year-old male underwent an arthroscopic Bankart repair for recurrent shoulder dislocation. The surgery was performed in the beach chair position and lasted two hours. At the end of the procedure, the patient was found to have left pectoral swelling. A chest radiography showed no abnormality. Pectoral swelling due to fluid extravasation after shoulder arthroscopy has not previously been documented. PMID:26889473

  9. Multiple Brain Abscesses due to Streptococcus anginosus: Prediction of Mortality by an Imaging Severity Index Score.

    PubMed

    Kragha, K O

    2016-01-01

    An elderly patient with altered mental status, brain abscesses, ventriculitis, and empyemas died of septic shock and brain abscesses secondary to Streptococcus anginosus despite aggressive treatment. An imaging severity index score with a better prognostic value than the Glasgow coma scale predicted mortality in this patient. PMID:27034878

  10. Multiple Brain Abscesses due to Streptococcus anginosus: Prediction of Mortality by an Imaging Severity Index Score

    PubMed Central

    2016-01-01

    An elderly patient with altered mental status, brain abscesses, ventriculitis, and empyemas died of septic shock and brain abscesses secondary to Streptococcus anginosus despite aggressive treatment. An imaging severity index score with a better prognostic value than the Glasgow coma scale predicted mortality in this patient. PMID:27034878

  11. The costs of traumatic brain injury due to motorcycle accidents in Hanoi, Vietnam

    PubMed Central

    Hoang, Hanh TM; Pham, Tran L; Vo, Thuy TN; Nguyen, Phuong K; Doran, Christopher M; Hill, Peter S

    2008-01-01

    Background Road traffic accidents are the leading cause of fatal and non-fatal injuries in Vietnam. The purpose of this study is to estimate the costs, in the first year post-injury, of non-fatal traumatic brain injury (TBI) in motorcycle users not wearing helmets in Hanoi, Vietnam. The costs are calculated from the perspective of the injured patients and their families, and include quantification of direct, indirect and intangible costs, using years lost due to disability as a proxy. Methods The study was a retrospective cross-sectional study. Data on treatment and rehabilitation costs, employment and support were obtained from patients and their families using a structured questionnaire and The European Quality of Life instrument (EQ6D). Results Thirty-five patients and their families were interviewed. On average, patients with severe, moderate and minor TBI incurred direct costs at USD 2,365, USD 1,390 and USD 849, with time lost for normal activities averaging 54 weeks, 26 weeks and 17 weeks and years lived with disability (YLD) of 0.46, 0.25 and 0.15 year, respectively. Conclusion All three component costs of TBI were high; the direct cost accounted for the largest proportion, with costs rising with the severity of TBI. The results suggest that the burden of TBI can be catastrophic for families because of high direct costs, significant time off work for patients and caregivers, and impact on health-related quality of life. Further research is warranted to explore the actual social and economic benefits of mandatory helmet use. PMID:18718026

  12. Computational Morphometry for Detecting Changes in Brain Structure Due to Development, Aging, Learning, Disease and Evolution

    PubMed Central

    Mietchen, Daniel; Gaser, Christian

    2009-01-01

    The brain, like any living tissue, is constantly changing in response to genetic and environmental cues and their interaction, leading to changes in brain function and structure, many of which are now in reach of neuroimaging techniques. Computational morphometry on the basis of Magnetic Resonance (MR) images has become the method of choice for studying macroscopic changes of brain structure across time scales. Thanks to computational advances and sophisticated study designs, both the minimal extent of change necessary for detection and, consequently, the minimal periods over which such changes can be detected have been reduced considerably during the last few years. On the other hand, the growing availability of MR images of more and more diverse brain populations also allows more detailed inferences about brain changes that occur over larger time scales, way beyond the duration of an average research project. On this basis, a whole range of issues concerning the structures and functions of the brain are now becoming addressable, thereby providing ample challenges and opportunities for further contributions from neuroinformatics to our understanding of the brain and how it changes over a lifetime and in the course of evolution. PMID:19707517

  13. [The efficacy of botulinum toxin therapy in patients with upper limb spasticity due to traumatic brain injury].

    PubMed

    Akulov, M A; Khat'kova, S E; Mokienko, O A; Orlova, O R; Usachev, D Yu; Zakharov, V O; Orlova, A S; Tomsky, A A

    2016-01-01

    Spasticity is a type of muscle hyperactivity that occurs in patients after focal lesions of the Central nervous system due to various diseases: stroke, traumatic brain injury or spinal cord injury, neurosurgical intervention, as well as multiple sclerosis and other diseases of the Central nervous system and is the most disability manifestation of the syndrome of upper motor neuron (UMNS). Focal spasticity of the upper limb requires a complex treatment. Botulinum toxin therapy is an effective treatment for focal/multifocal spasticity in reducing muscle tone and improving function with the highest level of evidence according to the latest American and European guidelines for treatment of spasticity. There are many publications devoted to BTA use in post-stroke patients. This article provides a review of the BTA use in patients with the upper limb spasticity due to severe traumatic brain injury. Some local data on the BTA efficacy in the cohort of patients with traumatic brain injury are also presented. PMID:27635608

  14. [The efficacy of botulinum toxin therapy in patients with upper limb spasticity due to traumatic brain injury].

    PubMed

    Akulov, M A; Khat'kova, S E; Mokienko, O A; Orlova, O R; Usachev, D Yu; Zakharov, V O; Orlova, A S; Tomsky, A A

    2016-01-01

    Spasticity is a type of muscle hyperactivity that occurs in patients after focal lesions of the Central nervous system due to various diseases: stroke, traumatic brain injury or spinal cord injury, neurosurgical intervention, as well as multiple sclerosis and other diseases of the Central nervous system and is the most disability manifestation of the syndrome of upper motor neuron (UMNS). Focal spasticity of the upper limb requires a complex treatment. Botulinum toxin therapy is an effective treatment for focal/multifocal spasticity in reducing muscle tone and improving function with the highest level of evidence according to the latest American and European guidelines for treatment of spasticity. There are many publications devoted to BTA use in post-stroke patients. This article provides a review of the BTA use in patients with the upper limb spasticity due to severe traumatic brain injury. Some local data on the BTA efficacy in the cohort of patients with traumatic brain injury are also presented.

  15. Swell-Dissipation Function for Wave Models

    NASA Astrophysics Data System (ADS)

    Babanin, A.

    2012-04-01

    In the paper, we will investigate swell attenuation due to production of turbulence by the wave orbital motion. Theoreticaly, potential waves cannot generate the vortex motion, but the scale considerations indicate that if the steepness of waves is not too small, the Reynolds number can exceed the critical values. This means that in presence of initial non-potential disturbances the orbital velocities can generate the vortex motion and turbulence. This problem was investigated by laboratory means, numerical simulations and field observations. As a sink of wave energy, such dissipation is small in presence of wave breaking, but is essential for swell. Swell prediction by spectral wave models is often poor, but is important for offshore and maritime industry, and across a broad range of oceanographic and air-sea interaction applications. Based on the research of wave-induced turbulence, new swell-dissipation function is proposed. It agrees well with satellite observations of long-distance swell propagation and has been employed and tested in spectral wave models.

  16. Swelling and Stress Relaxation in Portland Brownstone

    NASA Astrophysics Data System (ADS)

    Jimenez, I.; Scherer, G.

    2003-04-01

    Portland Brownstone (PB) is an arkose sandstone extensively used in the northeast-ern USA during the nineteenth century. This reddish-brown stone contains a fraction of swelling clays that are thought to contribute to its degradation upon cycles of wet-ting and drying. During drying events, contraction of the drying surface leads to stresses approaching the tensile strength of the stone. However, we have found that the magnitude of these stresses is limited by the ability of the stone to undergo stress relaxation. In this paper we describe novel methods to determine the magnitude of the stresses and the rate at which they develop and relax. We also discuss the influ-ence of surfactants on the magnitude of swelling and the rate of the stress relaxation of PB. The implications of our findings for the understanding of damage due to swelling of clays are discussed.

  17. Traumatic Brain Injury Due to Bull Assault in a Girl: a Case Report

    PubMed Central

    ALVIS-MIRANDA, Hernando Raphael; CASTELLAR-LEONES, Sandra Milena; VELÁSQUEZ-LOPERENA, Dufays Danith; VILLA-DELGADO, Rosmery; ALCALA-CERRA, Gabriel; MOSCOTE-SALAZAR, Luis Rafael

    2013-01-01

    ABSTRACT Traumatic brain injury is a common condition in the emergency services, affecting the pediatric and adult population significantly. Patterns of head injury as well as management principles in children are important differences compared to adults. Traumatic brain injury by bull rush is usually seen in adults but has not been described in children-report a pediatric cranial trauma present bull rush, which to our knowledge is the first report in the literature of this nature. PMID:24790672

  18. Stress Singularities in Swelling Soft Solids

    NASA Astrophysics Data System (ADS)

    Goriely, Alain; Weickenmeier, Johannes; Kuhl, Ellen

    2016-09-01

    When a swelling soft solid is rigidly constrained on all sides except for a circular opening, it will bulge out to expand as observed during decompressive craniectomy, a surgical procedure used to reduce stresses in swollen brains. While the elastic energy of the solid decreases throughout this process, large stresses develop close to the opening. At the point of contact, the stresses exhibit a singularity similar to the ones found in the classic punch indentation problem. Here, we study the stresses generated by swelling and the evolution of the bulging shape associated with this process. We also consider the possibility of damage triggered by zones of either high shear stresses or high fiber stretches.

  19. Neonatal Brain Abscess due to Extended-Spectrum Beta-Lactamase Producing Klebsiella pneumoniae

    PubMed Central

    Mondal, Monojit; Thapa, Rajoo; Mallick, Debkrishna; Datta, Asok Kumar

    2014-01-01

    Klebsiella pneumoniae (K. pneumoniae) causing brain abscess in newborn infants is rare. Presented herein, is a 27-day-old male neonate who developed two frontal lobe abscesses in association with K. pneumoniae sepsis and meningitis. Antibiotic susceptibility testing utilizing the double-disk synergy method (Cefotaxime and Amoxycillin-Clavulanate) confirmed the extended spectrum beta-lactamase (ESBL) production by the isolate. He was treated simultaneously with antibiotics (Meropenem and Amikacin) and abscess aspiration through the anterior fontanelle, with less than satisfactory outcome. ESBL producing K. pneumoniae brain abscess in neonates is extremely rare in the English literature. Emperical carbapenems and aminoglycoside coverage in neonates with K. pneumoniae sepsis and brain abscess, especially in areas with high rate of ESBL producing bacteria may be warranted. PMID:25584278

  20. Impact of metal artefacts due to EEG electrodes in brain PET/CT imaging.

    PubMed

    Lemmens, Catherine; Montandon, Marie-Louise; Nuyts, Johan; Ratib, Osman; Dupont, Patrick; Zaidi, Habib

    2008-08-21

    The goal of this study is to investigate the impact of electroencephalogram (EEG) electrodes on the visual quality and quantification of (18)F-FDG PET images in neurological PET/CT examinations. For this purpose, the scans of 20 epilepsy patients with EEG monitoring were used. The CT data were reconstructed with filtered backprojection (FBP) and with a metal artefact reduction (MAR) algorithm. Both data sets were used for CT-based attenuation correction (AC) of the PET data. Also, a calculated AC (CALC) technique was considered. A volume of interest (VOI)-based analysis and a voxel-based quantitative analysis were performed to compare the different AC methods. Images were also evaluated visually by two observers. It was shown with simulations and phantom measurements that from the considered AC methods, the MAR-AC can be used as the reference in this setting. The visual assessment of PET images showed local hot spots outside the brain corresponding to the locations of the electrodes when using FBP-AC. In the brain, no abnormalities were observed. The quantitative analysis showed a very good correlation between PET-FBP-AC and PET-MAR-AC, with a statistically significant positive bias in the PET-FBP-AC images of about 5-7% in most brain voxels. There was also good correlation between PET-CALC-AC and PET-MAR-AC, but in the PET-CALC-AC images, regions with both a significant positive and negative bias were observed. EEG electrodes give rise to local hot spots outside the brain and a positive quantification bias in the brain. However, when diagnosis is made by mere visual assessment, the presence of EEG electrodes does not seem to alter the diagnosis. When quantification is performed, the bias becomes an issue especially when comparing brain images with and without EEG monitoring.

  1. Cerebral Schistosomiasis Due to Schistosoma haematobium Confirmed by PCR Analysis of Brain Specimen▿

    PubMed Central

    Imai, Kentaro; Koibuchi, Tomohiko; Kumagai, Takashi; Maeda, Takuya; Osada, Yoshio; Ohta, Nobuo; Koga, Michiko; Nakamura, Hitomi; Miura, Toshiyuki; Iwamoto, Aikichi; Fujii, Takeshi

    2011-01-01

    The case of a 25-year-old Japanese male who had cerebral schistosomiasis caused by Schistosoma haematobium is reported here. Although serum antibody tests showed a cross-reaction with other helminths and no ova were excreted in urine or feces, the existence of Schistosoma haematobium in the brain was confirmed by PCR analysis. PMID:21849689

  2. Neonatal Neurobehavior and Diffusion MRI Changes in Brain Reorganization Due to Intrauterine Growth Restriction in a Rabbit Model

    PubMed Central

    Eixarch, Elisenda; Batalle, Dafnis; Illa, Miriam; Muñoz-Moreno, Emma; Arbat-Plana, Ariadna; Amat-Roldan, Ivan; Figueras, Francesc; Gratacos, Eduard

    2012-01-01

    brain reorganization due to fetal diseases. PMID:22347486

  3. Toll-like receptor 4 knockout ameliorates neuroinflammation due to lung-brain interaction in mechanically ventilated mice.

    PubMed

    Chen, Ting; Chen, Chang; Zhang, Zongze; Zou, Yufeng; Peng, Mian; Wang, Yanlin

    2016-08-01

    Toll-like receptor 4 (TLR4) is a crucial receptor in the innate immune system, and increasing evidence supports its role in inflammation, stress, and tissue injury, including injury to the lung and brain. We aimed to investigate the effects of TLR4 on neuroinflammation due to the lung-brain interaction in mechanically ventilated mice. Male wild-type (WT) C57BL/6 and TLR4 knockout (TLR4 KO) mice were divided into three groups: (1) control group (C): spontaneous breathing; (2) anesthesia group (A): spontaneous breathing under anesthesia; and (3) mechanical ventilation group (MV): 6h of MV under anesthesia. The behavioral responses of mice were tested with fear conditioning tests. The histological changes in the lung and brain were assessed using hematoxylin-eosin (HE) staining. The level of TLR4 mRNA in tissue was measured using reverse transcription-polymerase chain reaction (RT-PCR). The levels of inflammatory cytokines were measured with an enzyme-linked immunosorbent assay (ELISA). Microgliosis, astrocytosis, and the TLR4 immunoreactivity in the hippocampus were measured by double immunofluorescence. MV mice exhibited impaired cognition, and this impairment was less severe in TLR4 KO mice than in WT mice. In WT mice, MV increased TLR4 mRNA expression in the lung and brain. MV induced mild lung injury, which was prevented in TLR4 KO mice. MV mice exhibited increased levels of inflammatory cytokines, increased microglia and astrocyte activation. Microgliosis was alleviated in TLR4 KO mice. MV mice exhibited increased TLR4 immunoreactivity, which was expressed in microglia and astrocytes. These results demonstrate that TLR4 is involved in neuroinflammation due to the lung-brain interaction and that TLR4 KO ameliorates neuroinflammation due to lung-brain interaction after prolonged MV. In addition, Administration of a TLR4 antagonist (100μg/mice) to WT mice also significantly attenuated neuroinflammation of lung-brain interaction due to prolonged MV. TLR4 antagonism

  4. The Swelling of Olympic Gels

    NASA Astrophysics Data System (ADS)

    Lang, Michael; Fischer, Jakob; Werner, Marco; Sommer, Jens-Uwe

    2014-03-01

    The swelling equilibrium of Olympic gels is studied by Monte Carlo Simulations. We observe that gels consisting of flexible cyclic molecules of a higher degree of polymerization N show a smaller equilibrium swelling degree Q ~N - 0 . 28φ0- 0 . 72 for the same monomer volume fraction φ0 at network preparation. This observation is explained by a disinterpenetration process of overlapping non-concatenated polymers upon swelling. In the limit of a sufficiently large number of concatenations per cyclic molecule we expect that the equilibrium degree of swelling becomes proportional to φ0- 1 / 2 independent of N. Our results challenge current textbook models for the equilibrium degree of swelling of entangled polymer networks. Now at: Bio Systems Analysis Group, Jena Centre for Bioinformatics (JCB) and Department for Mathematics and Computer Sciences, Friedrich Schiller University of Jena, 07743 Jena, Germany.

  5. Multiple Brain Abscesses Due to Aspergillus Fumigatus in a Patient With Liver Cirrhosis

    PubMed Central

    Tang, Hung-Jen; Liu, Wei-Lun; Chang, Tsung Chain; Li, Ming-Chi; Ko, Wen-Chien; Wu, Chi-Jung; Chuang, Yin-Ching; Lai, Chih-Cheng

    2016-01-01

    Abstract Invasive cerebral aspergillosis always developed in immunocompromised host. Early diagnosis may save life in this critical condition; however, it is difficult to reach. Herein, we presented an unusual case of invasive cerebral aspergillosis in a cirrhotic patient. A 47-year-old man presented with progressive deterioration of consciousness for three days. The patient had a history of alcoholic liver cirrhosis, Child-Pugh class C. Magnetic resonance imaging (MRI) of brain showed multi-focal parenchymal lesions, which was consistent with multiple brain abscesses. The diagnosis of invasive cerebral aspergillosis was made by molecular based laboratory methods including Aspergillus galactomannan antigen assay and oligonucleotide array. Despite treatment with the antifungal agent, Amphotericin B, the patient died at the ninth day of hospitalization. Our findings suggest that liver cirrhosis can be one of risk factors of invasive cerebral aspergillosis, and support the diagnosing usefulness of MRI, Aspergillus galactomannan antigen assay, and oligonucleotide array. PMID:26945363

  6. Multiple Brain Abscesses Due to Aspergillus Fumigatus in a Patient With Liver Cirrhosis: A Case Report.

    PubMed

    Tang, Hung-Jen; Liu, Wei-Lun; Chang, Tsung Chain; Li, Ming-Chi; Ko, Wen-Chien; Wu, Chi-Jung; Chuang, Yin-Ching; Lai, Chih-Cheng

    2016-03-01

    Invasive cerebral aspergillosis always developed in immunocompromised host. Early diagnosis may save life in this critical condition; however, it is difficult to reach. Herein, we presented an unusual case of invasive cerebral aspergillosis in a cirrhotic patient. A 47-year-old man presented with progressive deterioration of consciousness for three days. The patient had a history of alcoholic liver cirrhosis, Child-Pugh class C. Magnetic resonance imaging (MRI) of brain showed multi-focal parenchymal lesions, which was consistent with multiple brain abscesses. The diagnosis of invasive cerebral aspergillosis was made by molecular based laboratory methods including Aspergillus galactomannan antigen assay and oligonucleotide array. Despite treatment with the antifungal agent, Amphotericin B, the patient died at the ninth day of hospitalization. Our findings suggest that liver cirrhosis can be one of risk factors of invasive cerebral aspergillosis, and support the diagnosing usefulness of MRI, Aspergillus galactomannan antigen assay, and oligonucleotide array. PMID:26945363

  7. Mice with neuropathic pain exhibit morphine tolerance due to a decrease in the morphine concentration in the brain.

    PubMed

    Ochiai, Wataru; Kaneta, Mitsumasa; Nagae, Marina; Yuzuhara, Ami; Li, Xin; Suzuki, Haruka; Hanagata, Mika; Kitaoka, Satoshi; Suto, Wataru; Kusunoki, Yoshiki; Kon, Risako; Miyashita, Kazuhiko; Masukawa, Daiki; Ikarashi, Nobutomo; Narita, Minoru; Suzuki, Tsutomu; Sugiyama, Kiyoshi

    2016-09-20

    The chronic administration of morphine to patients with neuropathic pain results in the development of a gradual tolerance to morphine. Although the detailed mechanism of this effect has not yet been elucidated, one of the known causes is a decrease in μ-opioid receptor function with regard to the active metabolite of morphine, M-6-G(morphine-6-glucuronide), in the ventrotegmental area of the midbrain. In this study, the relationship between the concentration of morphine in the brain and its analgesic effect was examined after the administration of morphine in the presence of neuropathic pain. Morphine was orally administered to mice with neuropathic pain, and the relationship between morphine's analgesic effect and its concentration in the brain was analysed. In addition, the expression levels of the conjugation enzyme, UGT2B (uridine diphosphate glucuronosyltransferase), which has morphine as its substrate, and P-gp, which is a transporter involved in morphine excretion, were examined. In mice with neuropathic pain, the concentration of morphine in the brain was significantly decreased, and a correlation was found between this decrease and the decrease in the analgesic effect. It was considered possible that this decrease in the brain morphine concentration may be due to an increase in the expression level of P-gp in the small intestine and to an increase in the expression level and binding activity of UGT2B in the liver. The results of this study suggest the possibility that a sufficient analgesic effect may not be obtained when morphine is administered in the presence of neuropathic pain due to a decrease in the total amount of morphine and M-6-G that reach the brain. PMID:27102159

  8. Oxidative Stress in the Developing Rat Brain due to Production of Reactive Oxygen and Nitrogen Species

    PubMed Central

    Wilhelm, Jiří; Vytášek, Richard; Uhlík, Jiří; Vajner, Luděk

    2016-01-01

    Oxidative stress after birth led us to localize reactive oxygen and nitrogen species (RONS) production in the developing rat brain. Brains were assessed a day prenatally and on postnatal days 1, 2, 4, 8, 14, 30, and 60. Oxidation of dihydroethidium detected superoxide; 6-carboxy-2′,7′-dichlorodihydrofluorescein diacetate revealed hydrogen peroxide; immunohistochemical proof of nitrotyrosine and carboxyethyllysine detected peroxynitrite formation and lipid peroxidation, respectively. Blue autofluorescence detected protein oxidation. The foetuses showed moderate RONS production, which changed cyclically during further development. The periods and sites of peak production of individual RONS differed, suggesting independent generation. On day 1, neuronal/glial RONS production decreased indicating that increased oxygen concentration after birth did not cause oxidative stress. Dramatic changes in the amount and the sites of RONS production occurred on day 4. Nitrotyrosine detection reached its maximum. Day 14 represented other vast alterations in RONS generation. Superoxide production in arachnoidal membrane reached its peak. From this day on, the internal elastic laminae of blood vessels revealed the blue autofluorescence. The adult animals produced moderate levels of superoxide; all other markers reached their minimum. There was a strong correlation between detection of nitrotyrosine and carboxyethyllysine probably caused by lipid peroxidation initiated with RONS. PMID:27190574

  9. Cerebral salt-wasting syndrome due to hemorrhagic brain infarction: a case report

    PubMed Central

    2014-01-01

    Introduction Cerebral salt-wasting syndrome is a condition featuring hyponatremia and dehydration caused by head injury, operation on the brain, subarachnoid hemorrhage, brain tumor and so on. However, there are a few reports of cerebral salt-wasting syndrome caused by cerebral infarction. We describe a patient with cerebral infarction who developed cerebral salt-wasting syndrome in the course of hemorrhagic transformation. Case presentation A 79-year-old Japanese woman with hypertension and arrhythmia was admitted to our hospital for mild consciousness disturbance, conjugate deviation to right, left unilateral spatial neglect and left hemiparesis. Magnetic resonance imaging revealed a broad ischemic change in right middle cerebral arterial territory. She was diagnosed as cardiogenic cerebral embolism because atrial fibrillation was detected on electrocardiogram on admission. She showed hyponatremia accompanied by polyuria complicated at the same time with the development of hemorrhagic transformation on day 14 after admission. Based on her hypovolemic hyponatremia, she was evaluated as not having syndrome of inappropriate secretion of antidiuretic hormone but cerebral salt-wasting syndrome. She fortunately recovered with proper fluid replacement and electrolyte management. Conclusions This is a rare case of cerebral infarction and cerebral salt-wasting syndrome in the course of hemorrhagic transformation. It may be difficult to distinguish cerebral salt-wasting syndrome from syndrome of inappropriate antidiuretic hormone, however, an accurate assessment is needed to reveal the diagnosis of cerebral salt-wasting syndrome because the recommended fluid management is opposite in the two conditions. PMID:25055823

  10. Human brain microvascular endothelial cells resist elongation due to shear stress.

    PubMed

    Reinitz, Adam; DeStefano, Jackson; Ye, Mao; Wong, Andrew D; Searson, Peter C

    2015-05-01

    Endothelial cells in straight sections of vessels are known to elongate and align in the direction of flow. This phenotype has been replicated in confluent monolayers of bovine aortic endothelial cells and human umbilical vein endothelial cells (HUVECs) in cell culture under physiological shear stress. Here we report on the morphological response of human brain microvascular endothelial cells (HBMECs) in confluent monolayers in response to shear stress. Using a microfluidic platform we image confluent monolayers of HBMECs and HUVECs under shear stresses up to 16 dyne cm(-2). From live-cell imaging we quantitatively analyze the cell morphology and cell speed as a function of time. We show that HBMECs do not undergo a classical transition from cobblestone to spindle-like morphology in response to shear stress. We further show that under shear stress, actin fibers are randomly oriented in the cells indicating that there is no cytoskeletal remodeling. These results suggest that HBMECs are programmed to resist elongation and alignment under shear stress, a phenotype that may be associated with the unique properties of the blood-brain barrier.

  11. Prevention and Treatment of Traumatic Brain Injury Due to Rapid-Onset Natural Disasters

    PubMed Central

    Regens, James L.; Mould, Nick

    2014-01-01

    The prevention and treatment of traumatic brain injury (TBI) attributable to rapid-onset natural disasters is a major challenge confronting disaster preparedness planners and emergency medical personnel responding to those incidents. The kinetic energy released by rapid-onset natural disasters such as earthquakes, hurricanes or typhoons, and tornadoes can cause mild, moderate, or severe TBIs. As a result, neurotrauma is a major risk factor for mortality and morbidity outcomes within the spatial domain impacted by a rapid-onset natural disaster. This review article elucidates major challenges associated with immediate emergency medical response, long-term care, and prevention of post-event increases in pediatric TBIs because of child abuse when rapid-onset natural disasters occur. PMID:24783188

  12. Manic Symptoms Due to Methylphenidate Use in an Adolescent with Traumatic Brain Injury.

    PubMed

    Ekinci, Ozalp; Direk, Meltem Çobanoğullari; Ekinci, Nuran; Okuyaz, Cetin

    2016-08-31

    Almost one-fifth of children who sustain a traumatic brain injury (TBI) are under the risk of attention problems after injury. The efficacy and tolerability of methylphenidate (MPH) in children with a history of TBI have not been completely identified. In this case report, MPH-induced manic symptoms in an adolescent with TBI will be summarized. A male patient aged 17 years was admitted with the complaints of attention difficulties on schoolwork and forgetfullness which became evident after TBI. Long-acting MPH was administered with the dose of 18 mg/day for attention problems. After one week, patient presented with the complaints of talking to himself, delusional thoughts, irritability and sleeplessness. This case highlights the fact that therapeutic dose of MPH may cause mania-like symptoms in children with TBI. Close monitarization and slow dose titration are crucial when considering MPH in children with TBI. PMID:27489389

  13. Prevention and treatment of traumatic brain injury due to rapid-onset natural disasters.

    PubMed

    Regens, James L; Mould, Nick

    2014-01-01

    The prevention and treatment of traumatic brain injury (TBI) attributable to rapid-onset natural disasters is a major challenge confronting disaster preparedness planners and emergency medical personnel responding to those incidents. The kinetic energy released by rapid-onset natural disasters such as earthquakes, hurricanes or typhoons, and tornadoes can cause mild, moderate, or severe TBIs. As a result, neurotrauma is a major risk factor for mortality and morbidity outcomes within the spatial domain impacted by a rapid-onset natural disaster. This review article elucidates major challenges associated with immediate emergency medical response, long-term care, and prevention of post-event increases in pediatric TBIs because of child abuse when rapid-onset natural disasters occur.

  14. Prevention and treatment of traumatic brain injury due to rapid-onset natural disasters.

    PubMed

    Regens, James L; Mould, Nick

    2014-01-01

    The prevention and treatment of traumatic brain injury (TBI) attributable to rapid-onset natural disasters is a major challenge confronting disaster preparedness planners and emergency medical personnel responding to those incidents. The kinetic energy released by rapid-onset natural disasters such as earthquakes, hurricanes or typhoons, and tornadoes can cause mild, moderate, or severe TBIs. As a result, neurotrauma is a major risk factor for mortality and morbidity outcomes within the spatial domain impacted by a rapid-onset natural disaster. This review article elucidates major challenges associated with immediate emergency medical response, long-term care, and prevention of post-event increases in pediatric TBIs because of child abuse when rapid-onset natural disasters occur. PMID:24783188

  15. Manic Symptoms Due to Methylphenidate Use in an Adolescent with Traumatic Brain Injury

    PubMed Central

    Ekinci, Ozalp; Direk, Meltem Çobanoğullari; Ekinci, Nuran; Okuyaz, Cetin

    2016-01-01

    Almost one-fifth of children who sustain a traumatic brain injury (TBI) are under the risk of attention problems after injury. The efficacy and tolerability of methylphenidate (MPH) in children with a history of TBI have not been completely identified. In this case report, MPH-induced manic symptoms in an adolescent with TBI will be summarized. A male patient aged 17 years was admitted with the complaints of attention difficulties on schoolwork and forgetfullness which became evident after TBI. Long-acting MPH was administered with the dose of 18 mg/day for attention problems. After one week, patient presented with the complaints of talking to himself, delusional thoughts, irritability and sleeplessness. This case highlights the fact that therapeutic dose of MPH may cause mania-like symptoms in children with TBI. Close monitarization and slow dose titration are crucial when considering MPH in children with TBI. PMID:27489389

  16. On the Pressure Response in the Brain due to Short Duration Blunt Impacts

    PubMed Central

    Pearce, Christopher W.; Young, Philippe G.

    2014-01-01

    When the head is subject to non-penetrating (blunt) impact, contusion-type injuries are commonly identified beneath the impact site (the coup) and, in some instances, at the opposite pole (the contre-coup). This pattern of injury has long eluded satisfactory explanation and blunt head injury mechanisms in general remain poorly understood. There are only a small number of studies in the open literature investigating the head's response to short duration impacts, which can occur in collisions with light projectiles. As such, the head impact literature to date has focussed almost exclusively on impact scenarios which lead to a quasi-static pressure response in the brain. In order to investigate the response of the head to a wide range of impact durations, parametric numerical studies were performed on a highly bio-fidelic finite element model of the human head created from in vivo magnetic resonance imaging (MRI) scan data with non-linear tissue material properties. We demonstrate that short duration head impacts can lead to potentially deleterious transients of positive and negative intra-cranial pressure over an order of magnitude larger than those observed in the quasi-static regime despite reduced impact force and energy. The onset of this phenomenon is shown to be effectively predicted by the ratio of impact duration to the period of oscillation of the first ovalling mode of the system. These findings point to dramatically different pressure distributions in the brain and hence different patterns of injury depending on projectile mass, and provide a potential explanation for dual coup/contre-coup injuries observed clinically. PMID:25478695

  17. [A peculiar speech disorder due to bomb injury of the brain].

    PubMed

    Hem, Erlend

    2006-12-14

    Oslo was bombed by British bombers 6 September 1941, and a 28-year-old woman was hit on the head by a bomb fragment. She was seriously wounded with a large defect in the cranium frontally on the left side, and it was believed that she was not going to survive. She was unconscious for 3-4 days, and when she woke up she had right-sided hemiplegia and complete aphasia. She gradually recovered, and two months later she was discharged from hospital. Remarkably, the brain damage had altered her melody of language, and she spoke with a German-like accent. This led to problems for her during the war: she was for example not served in shops. The case story was published after the war by the Norwegian neurologist Georg Herman Monrad-Krohn (1884-1964), and it is the best known case of the so-called foreign accent syndrome. In this paper, this rare syndrome is presented, emphasising Monrad-Krohn's patient and based on his writings and the patient's medical record.

  18. Are the changes in the peripheral brain-derived neurotrophic factor levels due to platelet activation?

    PubMed Central

    Serra-Millàs, Montserrat

    2016-01-01

    Brain-derived neurotrophic factor (BDNF) plays an important role in central nervous system development, neurogenesis and neuronal plasticity. BDNF is also expressed in several non-neuronal tissues, and it could play an important role in other processes, such as cancer, angiogenesis, etc. Platelets are the major source of peripheral BDNF. However, platelets also contain high amounts of serotonin; they express specific surface receptors during activation, and a multitude of pro-inflammatory and immunomodulatory bioactive compounds are secreted from the granules. Until recently, there was insufficient knowledge regarding the relationship between BDNF and platelets. Recent studies showed that BDNF is present in two distinct pools in platelets, in α-granules and in the cytoplasm, and only the BDNF in the granules is secreted following stimulation, representing 30% of the total BDNF in platelets. BDNF has an important role in the pathophysiology of depression. Low levels of serum BDNF have been described in patients with major depressive disorder, and BDNF levels increased with chronic antidepressant treatment. Interestingly, there is an association between depression and platelet function. This review analyzed studies that evaluated the relationship between BDNF and platelet activation and the effect of treatments on both parameters. Only a few studies consider this possible confounding factor, and it could be very important in diseases such as depression, which show changes in both parameters. PMID:27014600

  19. Brain

    MedlinePlus

    ... will return after updating. Resources Archived Modules Updates Brain Cerebrum The cerebrum is the part of the ... the outside of the brain and spinal cord. Brain Stem The brain stem is the part of ...

  20. Pain hypersensitivity induced by paradoxical sleep deprivation is not due to altered binding to brain mu-opioid receptors.

    PubMed

    Nascimento, Danielle C; Andersen, Monica L; Hipólide, Débora Cristina; Nobrega, José N; Tufik, Sergio

    2007-03-28

    Previous studies have established a relationship between sleep disruption and pain, and it has been suggested that hyperalgesia induced by paradoxical sleep deprivation (PSD) could be due to a reduction of opioidergic neurotransmission in the brain. In the present study rats deprived of sleep for 96 h as well as rats allowed to recover for 24h after PSD and normal controls received vehicle or morphine (2.5, 5 and 10 mg/kg, i.p.) and were tested on a hot plate 1h later. Quantitative receptor autoradiography was used to map alterations in binding to brain mu-opioid receptors in separate groups. Results demonstrated that PSD induced a significant reduction in thermal pain threshold, as measured by paw withdrawal latencies. This effect did not return to baseline control values after 24h of sleep recovery. The usual analgesic effect of morphine was observed in the control group but not in PSD or rebound groups except at the highest dose (10 mg/kg). Binding of [3H]DAMGO to mu sites did not differ significantly among the three groups in any of the 33 brain regions examined. These results do not exclude the participation of the opioid system in PSD-induced pain hypersensitivity since sleep-deprived rats were clearly resistant to morphine. However, the fact no changes were seen in [3H]DAMGO binding indicates that mechanisms other than altered mu-opioid binding must be sought to explain the phenomenon.

  1. Uncovering Latent Deficits Due to Mild Traumatic Brain Injury by Using Normobaric Hypoxia Stress

    PubMed Central

    Temme, Leonard; Bleiberg, Joseph; Reeves, Dennis; Still, David L.; Levinson, Dan; Browning, Rebecca

    2013-01-01

    Memory deficits and other cognitive symptoms frequently associated with mTBI are commonly thought to resolve within 7–10 days. This generalization is based principally on observations made in individuals who are in the unstressed environmental conditions typical of a clinic and so does not consider the impact of physiologic, environmental, or psychological stress. Normobaric hypoxic stress can be generated with normal mean sea level (MSL) air, which is about 21% oxygen (O2) and 78% nitrogen (N), by reducing the percentage of O2 and increasing the percentage of N so that the resultant mixed-gas has a partial pressure of O2 approximating that of specified altitudes. This technique was used to generate normobaric hypoxic equivalents of 8,000, 12,000, and 14,000 feet above MSL in a group of 36 volunteers with a mTBI history and an equal number of controls matched on the basis of age, gender, tobacco smoking consumption, weight, height, and body mass index. Short-term visual memory was tested using the Matching to Sample (M2S) subtest of the BrainCheckers analog of the Automated Neuropsychological Assessment Metrics. Although there were no significant differences in M2S performance between the two groups of subjects at MSL, with increased altitude, the mTBI group performance was significantly worse than that of the control group. When the subjects were returned to MSL, the difference disappeared. This finding suggests that the “hypoxic challenge” paradigm developed here has potential clinical utility for assessing the effects of mTBI in individuals who appear asymptomatic under normal conditions. PMID:23641232

  2. Variation in hominid brain size: how much is due to method?

    PubMed

    De Miguel, C; Henneberg, M

    2001-01-01

    Brain size represented by cranial capacity (CC) is one of the most frequently analysed characters of hominids. Accuracy of individual CC estimates depends on completeness of specimens and methods used for reconstruction and measurement. A file of published estimates of CC of hominids dated from 3.2 Ma (million years) to 10 Ka (thousand years) including 606 estimates for 243 specimens was compiled. In the file, 75 specimens are available with multiple values (3 to 15) obtained by various methods and/or by various authors. Using individuals as classes in ANOVA, intraclass variation, which represents "error" of estimates, was calculated. For the total sample of multiple estimates (N = 382) the error variance is 5315 ml2. The error standard deviation is 73 ml (coefficient of variation (CV = 7.3%), quite large in comparison to the actual variation in CC in modern humans, SD = 157 ml (CV = 11.6%). This large error makes us wonder whether any fossil can be reliably placed with respect to a particular "cerebral Rubicon" between palaeospecies. Recent discussions concerning cranial capacity of Stw505 are a case in point regarding errors in CC estimation. In actual repeated 30 time measurements on a research quality cast we obtained with various methods (water, seeds, plasticine) CC estimates ranging from 484 to 586 ml. The range of estimates in the literature is from 515 to 625 ml. When hominid CC by taxon with date as a covariate is subjected to ANOVA, taxon is responsible for 5% of the variance while date is responsible for the main portion, (89%). The relationship between CC and date is best characterised as a gradual time trend. It is proven by the ANOVA test for linearity, by gamma test for trend and by ASReml fitting of a linear function. The line of best fit to this time trend is a double exponential curve which explains 90% of the total variance in CC: CC = 306.63 (4.83(0.9995)DATE) Essentially the same curve fits subsamples of CC dated at less than 1 Ma and at 3

  3. Biophysics: Unfolding the brain

    NASA Astrophysics Data System (ADS)

    Kuhl, Ellen

    2016-06-01

    The folded surface of the human brain, although striking, continues to evade understanding. Experiments with swelling gels now fuel the notion that brain folding is modulated by physical forces, and not by genetic, biological or chemical events alone.

  4. Delayed Brain Infarction due to Bilateral Vertebral Artery Occlusion Which Occurred 5 Days after Cervical Trauma.

    PubMed

    Jang, Donghwan; Kim, Choonghyo; Lee, Seung Jin; Kim, Jiha

    2014-08-01

    Vertebral artery (VA) injuries usually accompany cervical trauma. Although these injuries are commonly asymptomatic, some result in vertebrobasilar infarction. The symptoms of VA occlusion have been reported to usually manifest within 24 hours after trauma. The symptoms of bilateral VA occlusions seem to be more severe and seem to occur with shorter latencies than those of unilateral occlusions. A 48-year-old man had a C3-4 fracture-dislocation with spinal cord compression that resulted from a traffic accident. After surgery, his initial quadriparesis gradually improved. However, he complained of sudden headache and dizziness on the 5th postoperative day. His motor weakness was abruptly aggravated. Radiologic evaluation revealed an infarction in the occipital lobe and cerebellum. Cerebral angiography revealed complete bilateral VA occlusion. We administered anticoagulation therapy. After 6 months, his weakness had only partially improved. This case demonstrates that delayed infarction due to bilateral VA occlusion can occur at latencies as long as 5 days. Thus, we recommend that patients with cervical traumas that may be accompanied by bilateral VA occlusion should be closely observed for longer than 5 days.

  5. Cinnamon Polyphenols Attenuate Neuronal Death and Glial Swelling in Ischemic Injury

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brain edema is a major complication associated with ischemic stroke and is characterized by a volumetric enlargement of the brain. Astrocyte swelling is a major component of brain edema. We investigated the protective effects of polyphenols isolated from green tea and cinnamon in C6 glial cultures s...

  6. Swelling-resistant nuclear fuel

    DOEpatents

    Arsenlis, Athanasios; Satcher, Jr., Joe; Kucheyev, Sergei O.

    2011-12-27

    A nuclear fuel according to one embodiment includes an assembly of nuclear fuel particles; and continuous open channels defined between at least some of the nuclear fuel particles, wherein the channels are characterized as allowing fission gasses produced in an interior of the assembly to escape from the interior of the assembly to an exterior thereof without causing significant swelling of the assembly. Additional embodiments, including methods, are also presented.

  7. Managing Chemotherapy Side Effects: Swelling (Fluid Retention)

    MedlinePlus

    ... ancer I nstitute Managing Chemotherapy Side Effects Swelling (Fluid retention) “My hands and feet were swollen and ... at one time. Managing Chemotherapy Side Effects: Swelling (Fluid retention) Weigh yourself. l Weigh yourself at the ...

  8. Incidental 11C-choline PET/CT brain uptake due to meningioma in a patient studied for prostate cancer: correlation with MRI and imaging fusion.

    PubMed

    Bertagna, Francesco; Bosio, Giovanni; Pinelli, Lorenzo; Treglia, Giorgio; Giubbini, Raffaele

    2013-11-01

    We report a case of a 75-year-old male patient treated with radiotherapy in 1999 for prostate cancer. Due to a rise in prostate-specific antigen, he underwent (11)C-choline PET/CT. The study was negative for secondary lesions but revealed an incidental pathologic focal brain uptake. A subsequent magnetic resonance examination confirmed the presence of a brain lesion typical for meningioma.

  9. Changes in Brain Metallome/Metabolome Pattern due to a Single i.v. Injection of Manganese in Rats

    PubMed Central

    Neth, Katharina; Lucio, Marianna; Walker, Alesia; Zorn, Julia; Schmitt-Kopplin, Philippe; Michalke, Bernhard

    2015-01-01

    Exposure to high concentrations of Manganese (Mn) is known to potentially induce an accumulation in the brain, leading to a Parkinson related disease, called manganism. Versatile mechanisms of Mn-induced brain injury are discussed, with inactivation of mitochondrial defense against oxidative stress being a major one. So far, studies indicate that the main Mn-species entering the brain are low molecular mass (LMM) compounds such as Mn-citrate. Applying a single low dose MnCl2 injection in rats, we observed alterations in Mn-species pattern within the brain by analysis of aqueous brain extracts by size-exclusion chromatography—inductively coupled plasma mass spectrometry (SEC-ICP-MS). Additionally, electrospray ionization—ion cyclotron resonance-Fourier transform-mass spectrometry (ESI-ICR/FT-MS) measurement of methanolic brain extracts revealed a comprehensive analysis of changes in brain metabolisms after the single MnCl2 injection. Major alterations were observed for amino acid, fatty acid, glutathione, glucose and purine/pyrimidine metabolism. The power of this metabolomic approach is the broad and detailed overview of affected brain metabolisms. We also correlated results from the metallomic investigations (Mn concentrations and Mn-species in brain) with the findings from metabolomics. This strategy might help to unravel the role of different Mn-species during Mn-induced alterations in brain metabolism. PMID:26383269

  10. [Brain Abscess due to Infection with Dematiaceous Fungi Cladophialophora bantiana Associated with Hypogammaglobulinemia Following Gastrectomy: A Case Report].

    PubMed

    Shimogawa, Takafumi; Sayama, Tetsuro; Haga, Sei; Akiyama, Tomoaki; Makihara, Kosuke; Morioka, Takato

    2016-01-01

    Dematiaceous fungi have melanin-like pigment in the cell wall and usually cause a variety of dermal infections in humans. Infections of the central nervous system(cerebral phaeohyphomycosis)are rare but serious, since they commonly occur in immunocompromized patients. A 76-year-old man was admitted with mild motor aphasia and underwent total excision of a mass in the left frontal lobe. With the postoperative diagnosis of brain abscess due to infection with dematiaceous fungi (C. bantiana) associated with hypogammaglobulinemia following gastrectomy, intravenous antifungal drugs including amphotericin B and fluconazole were administered. Regrowth of the abscess with intraventricular rupture was noted at about the 88th day after the initial surgery, and the patient underwent neuroendoscopic aspiration of the pus and placement of a ventricular drain. Following intraventricular administration of miconazole through ventricular drainage or an Ommaya reservoir, neuroradiological findings improved, but general and neurological conditions worsened. Further treatment was discontinued and the patient died 9 months after onset. The poor outcome in this patient is attributed to 1)intractability of dematiaceous fungi, 2)development of ventriculitis and the need for intraventricular administration of antifungal drugs, and 3)untreatable hypogammaglobulinemia following gastrectomy. PMID:26771098

  11. Conservation of clay-bearing stones: Understanding the swelling and damage mechanisms

    NASA Astrophysics Data System (ADS)

    Wangler, Timothy

    Certain sandstones used in historic monuments and decorative building facades may contain clays that swell upon wetting, producing differential strains during wetting and drying cycles and leading to the development of stresses that are on the order of the strength of the stone. This leads to damage observed in the field as buckling and surface delamination, damage expected to occur during a wetting cycle as a thin wet layer of stone goes into compression relative to the bulk of the dry stone. Clays swell due to hydration of counterbalancing cations that exist between the negatively charged aluminosilicate layers that make up a clay particle. This swelling has been observed to occur over two distinct ranges: short-range, discrete intracrystalline swelling, and long-range, continuous, osmotic swelling. Additionally, it has been shown that swelling can be reduced, but not eliminated, by exchanging the counterbalancing cations in the interlayer with alpha,o diaminoalkanes. In order to mitigate damage due to swelling, it is important to understand the mechanism by which clays swell, the mechanism by which alpha,o diaminoalkanes inhibit swelling, and the mechanism by which damage occurs on a macroscopic level. In this work, it is shown that for the sandstones studied, clays swell almost entirely via intracrystalline swelling and that alpha,o diaminoalkanes inhibit swelling via ion exchange and subsequently reduced rehydration. A buckling damage mechanism is verified experimentally and a flaw propagation mechanism in which flaws can grow to a critical buckling size is explored. An understanding of the development of stresses during wetting is explored via a novel warping experiment and swelling pressure experiments.

  12. Scrotal Swelling in the Neonate

    PubMed Central

    Basta, Amaya M.; Courtier, Jesse; Phelps, Andrew; Copp, Hillary L.; MacKenzie, John D.

    2016-01-01

    Discovery of scrotal swelling in a neonate can be a source of anxiety for parents, clinicians, and sonologists alike. This pictorial essay provides a focused review of commonly encountered scrotal masses and mimics specific to the neonatal setting. Although malignancy is a concern, it is very uncommon, as most neonatal scrotal masses are benign. Key discriminating features and management options are highlighted to improve the radiologist’s ability to diagnose neonatal scrotal conditions and guide treatment decisions. Neonatal scrotal processes ranging from common to uncommon will be discussed. PMID:25715370

  13. Diffuse light reflectance signals as potential indicators of loss of viability in brain tissue due to hypoxia: charge-coupled-device-based imaging and fiber-based measurement

    NASA Astrophysics Data System (ADS)

    Kawauchi, Satoko; Nishidate, Izumi; Uozumi, Yoichi; Nawashiro, Hiroshi; Ashida, Hiroshi; Sato, Shunichi

    2013-01-01

    Brain tissue is highly vulnerable to ischemia/hypoxia, and real-time monitoring of its viability is important. By fiber-based measurements for rat brain, we previously observed a unique triphasic reflectance change (TRC) after a certain period of time after hypoxia. After TRC, rats could not be rescued, suggesting that TRC can be used as an indicator of loss of brain tissue viability. In this study, we investigated this diffuse-reflectance change due to hypoxia in three parts. First, we developed and validated a theoretical method to quantify changes in the absorption and reduced scattering coefficients involved in TRC. Second, we performed charge-coupled-device-based reflectance imaging of the rat brain during hypoxia followed by reoxygenation to examine spatiotemporal characteristics of the reflectance and its correlation with reversibility of brain tissue damage. Third, we made simultaneous imaging and fiber-based measurement of the reflectance for the rat to compare signals obtained by these two modalities. We observed a nontriphasic reflectance change by the imaging, and it was associated with brain tissue viability. We found that TRC measured by the fibers preceded the reflectance-signal change captured by the imaging. This time difference is attributable to the different observation depths in the brain with these two methods.

  14. Tamoxifen does not inhibit the swell activated chloride channel in human neutrophils during the respiratory burst

    SciTech Connect

    Ahluwalia, Jatinder

    2008-10-31

    Effective functioning of neutrophils relies upon electron translocation through the NADPH oxidase (NOX). The electron current generated (I{sub e}) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential in activated human neutrophils. Swelling activated chloride channels have been demonstrated in part to counteract the depolarisation generated by the NADPH oxidase I{sub e}. In the present study, the effects of inhibitors of swell activated chloride channels on ROS production and on the swelling activated chloride conductance was investigated in activated human neutrophils. Tamoxifen (10 {mu}M), a specific inhibitor for swell activated chloride channels in neutrophils, completely inhibited both the PMA and FMLP stimulated respiratory burst. This inhibition of the neutrophil respiratory burst was not due to the blocking effect of tamoxifen on the swelling activated chloride conductance in these cells. These results demonstrate that a tamoxifen insensitive swell activated chloride channel has important significance during the neutrophil respiratory burst.

  15. Swell Sleeves for Testing Explosive Devices

    NASA Technical Reports Server (NTRS)

    Hinkel, Todd J.; Dean, Richard J.; Hohmann, Carl W.; Hacker, Scott C.; Harrington, Douglas W.; Bacak, James W.

    2003-01-01

    A method of testing explosive and pyrotechnic devices involves exploding the devices inside swell sleeves. Swell sleeves have been used previously for measuring forces. In the present method, they are used to obtain quantitative indications of the energy released in explosions of the devices under test. A swell sleeve is basically a thick-walled, hollow metal cylinder threaded at one end to accept a threaded surface on a device to be tested (see Figure 1). Once the device has been tightly threaded in place in the swell sleeve, the device-and-swell-sleeve assembly is placed in a test fixture, then the device is detonated. After the explosion, the assembly is removed from the test fixture and placed in a coordinate-measuring machine for measurement of the diameter of the swell sleeve as a function of axial position. For each axial position, the original diameter of the sleeve is subtracted from the diameter of the sleeve as swollen by the explosion to obtain the diametral swelling as a function of axial position (see Figure 2). The amount of swelling is taken as a measure of the energy released in the explosion. The amount of swelling can be compared to a standard amount of swelling to determine whether the pyrotechnic device functioned as specified.

  16. Alkaline Ceramidase 3 Deficiency Results in Purkinje Cell Degeneration and Cerebellar Ataxia Due to Dyshomeostasis of Sphingolipids in the Brain.

    PubMed

    Wang, Kai; Xu, Ruijuan; Schrandt, Jennifer; Shah, Prithvi; Gong, Yong Z; Preston, Chet; Wang, Louis; Yi, Jae Kyo; Lin, Chih-Li; Sun, Wei; Spyropoulos, Demetri D; Rhee, Soyoung; Li, Mingsong; Zhou, Jie; Ge, Shaoyu; Zhang, Guofeng; Snider, Ashley J; Hannun, Yusuf A; Obeid, Lina M; Mao, Cungui

    2015-10-01

    Dyshomeostasis of both ceramides and sphingosine-1-phosphate (S1P) in the brain has been implicated in aging-associated neurodegenerative disorders in humans. However, mechanisms that maintain the homeostasis of these bioactive sphingolipids in the brain remain unclear. Mouse alkaline ceramidase 3 (Acer3), which preferentially catalyzes the hydrolysis of C18:1-ceramide, a major unsaturated long-chain ceramide species in the brain, is upregulated with age in the mouse brain. Acer3 knockout causes an age-dependent accumulation of various ceramides and C18:1-monohexosylceramide and abolishes the age-related increase in the levels of sphingosine and S1P in the brain; thereby resulting in Purkinje cell degeneration in the cerebellum and deficits in motor coordination and balance. Our results indicate that Acer3 plays critically protective roles in controlling the homeostasis of various sphingolipids, including ceramides, sphingosine, S1P, and certain complex sphingolipids in the brain and protects Purkinje cells from premature degeneration. PMID:26474409

  17. Alkaline Ceramidase 3 Deficiency Results in Purkinje Cell Degeneration and Cerebellar Ataxia Due to Dyshomeostasis of Sphingolipids in the Brain

    PubMed Central

    Preston, Chet; Wang, Louis; Yi, Jae Kyo; Lin, Chih-Li; Sun, Wei; Spyropoulos, Demetri D.; Rhee, Soyoung; Li, Mingsong; Zhou, Jie; Ge, Shaoyu; Zhang, Guofeng; Snider, Ashley J.; Hannun, Yusuf A.; Obeid, Lina M.; Mao, Cungui

    2015-01-01

    Dyshomeostasis of both ceramides and sphingosine-1-phosphate (S1P) in the brain has been implicated in aging-associated neurodegenerative disorders in humans. However, mechanisms that maintain the homeostasis of these bioactive sphingolipids in the brain remain unclear. Mouse alkaline ceramidase 3 (Acer3), which preferentially catalyzes the hydrolysis of C18:1-ceramide, a major unsaturated long-chain ceramide species in the brain, is upregulated with age in the mouse brain. Acer3 knockout causes an age-dependent accumulation of various ceramides and C18:1-monohexosylceramide and abolishes the age-related increase in the levels of sphingosine and S1P in the brain; thereby resulting in Purkinje cell degeneration in the cerebellum and deficits in motor coordination and balance. Our results indicate that Acer3 plays critically protective roles in controlling the homeostasis of various sphingolipids, including ceramides, sphingosine, S1P, and certain complex sphingolipids in the brain and protects Purkinje cells from premature degeneration. PMID:26474409

  18. Validity of semi-quantitative scale for brain MRI in unilateral cerebral palsy due to periventricular white matter lesions: Relationship with hand sensorimotor function and structural connectivity

    PubMed Central

    Fiori, Simona; Guzzetta, Andrea; Pannek, Kerstin; Ware, Robert S.; Rossi, Giuseppe; Klingels, Katrijn; Feys, Hilde; Coulthard, Alan; Cioni, Giovanni; Rose, Stephen; Boyd, Roslyn N.

    2015-01-01

    Aim To provide first evidence of construct validity of a semi-quantitative scale for brain structural MRI (sqMRI scale) in children with unilateral cerebral palsy (UCP) secondary to periventricular white matter (PWM) lesions, by examining the relationship with hand sensorimotor function and whole brain structural connectivity. Methods Cross-sectional study of 50 children with UCP due to PWM lesions using 3 T (MRI), diffusion MRI and assessment of hand sensorimotor function. We explored the relationship of lobar, hemispheric and global scores on the sqMRI scale, with fractional anisotropy (FA), as a measure of brain white matter microstructure, and with hand sensorimotor measures (Assisting Hand Assessment, AHA; Jebsen–Taylor Test for Hand Function, JTTHF; Melbourne Assessment of Unilateral Upper Limb Function, MUUL; stereognosis; 2-point discrimination). Results Lobar and hemispheric scores on the sqMRI scale contralateral to the clinical side of hemiplegia correlated with sensorimotor paretic hand function measures and FA of a number of brain structural connections, including connections of brain areas involved in motor control (postcentral, precentral and paracentral gyri in the parietal lobe). More severe lesions correlated with lower sensorimotor performance, with the posterior limb of internal capsule score being the strongest contributor to impaired hand function. Conclusion The sqMRI scale demonstrates first evidence of construct validity against impaired motor and sensory function measures and brain structural connectivity in a cohort of children with UCP due to PWM lesions. More severe lesions correlated with poorer paretic hand sensorimotor function and impaired structural connectivity in the hemisphere contralateral to the clinical side of hemiplegia. The quantitative structural MRI scoring may be a useful clinical tool for studying brain structure–function relationships but requires further validation in other populations of CP. PMID:26106533

  19. Malignant cerebral swelling following cranioplasty.

    PubMed

    Honeybul, S; Damodaran, O; Lind, C R P; Lee, G

    2016-07-01

    Over the past few years there have been a number of case reports and small cohort studies that have described so called "malignant" cerebral swelling following an uneventful cranioplasty procedure. The pathophysiology remains to be established however it has been suggested that it may be related to a combination of failure of autoregulation and the use of closed vacuum suction drainage. The current study presents three further patients who had had a decompressive hemicraniectomy for ischaemic stroke. If decompressive craniectomy is utilised in the management of neurological emergencies, close attention and wider reporting of this type of complication is required not only to focus attention on possible management strategies, but also to determine which patients are at most risk of this devastating complication. PMID:27189792

  20. Prediction of swelling rocks strain in tunneling

    NASA Astrophysics Data System (ADS)

    Parsapour, D.; Fahimifar, A.

    2016-05-01

    Swelling deformations leading to convergence of tunnels may result in significant difficulties during the construction, in particular for long term use of tunnels. By extracting an experimental based explicit analytical solution for formulating swelling strains as a function of time and stress, swelling strains are predicted from the beginning of excavation and during the service life of tunnel. Results obtained from the analytical model show a proper agreement with experimental results. This closed-form solution has been implemented within a numerical program using the finite element method for predicting time-dependent swelling strain around tunnels. Evaluating effects of swelling parameters on time-dependent strains and tunnel shape on swelling behavior around the tunnel according to this analytical solution is considered. The ground-support interaction and consequent swelling effect on the induced forces in tunnel lining is considered too. Effect of delay in lining installation on swelling pressure which acting on the lining and its structural integrity, is also evaluated. A MATLAB code of " SRAP" is prepared and applied to calculate all swelling analysis around tunnels based on analytical solution.

  1. BRAIN ABSCESS DUE TO Staphylococcus aureus OF CRYPTOGENIC SOURCE IN AN HIV-1 INFECTED PATIENT IN USE OF ANTIRETROVIRAL THERAPY

    PubMed Central

    de OLIVEIRA, Anna Paula Romero; PAPPALARDO, Mara Cristina; DANTAS, Daniel; LINS, Diogo; VIDAL, José Ernesto

    2016-01-01

    The spectrum of neurological complications associated with human immunodeficiency virus type 1 (HIV-1) infection is broad. The most frequent etiologies include primary diseases (caused by HIV itself) or secondary diseases (opportunistic infections or neoplasms). Despite these conditions, HIV-infected patients are susceptible to other infections observed in patients without HIV infection. Here we report a rare case of a brain abscess caused by Staphylococcus aureus in an HIV-infected patient. After drainage of the abscess and treatment with oxacilin, the patient had a favorable outcome. This case reinforces the importance of a timely neurosurgical procedure that supported adequate management of an unusual cause of expansive brain lesions in HIV-1 infected patients. PMID:27074328

  2. Treatment of persistent post-concussion syndrome due to mild traumatic brain injury: current status and future directions.

    PubMed

    Hadanny, Amir; Efrati, Shai

    2016-08-01

    Persistent post-concussion syndrome caused by mild traumatic brain injury has become a major cause of morbidity and poor quality of life. Unlike the acute care of concussion, there is no consensus for treatment of chronic symptoms. Moreover, most of the pharmacologic and non-pharmacologic treatments have failed to demonstrate significant efficacy on both the clinical symptoms as well as the pathophysiologic cascade responsible for the permanent brain injury. This article reviews the pathophysiology of PCS, the diagnostic tools and criteria, the current available treatments including pharmacotherapy and different cognitive rehabilitation programs, and promising new treatment directions. A most promising new direction is the use of hyperbaric oxygen therapy, which targets the basic pathological processes responsible for post-concussion symptoms; it is discussed here in depth.

  3. Comparing the Effect of Botulinum Toxin Type B Injection at Different Dosages for Patient with Drooling due to Brain Lesion

    PubMed Central

    Park, Hee Dong; Park, Sang Jun; Choi, Yong Min

    2012-01-01

    Objective To investigate Botulinum toxin type B (BNT-B) injection's effect and duration depending on dose for patients with brain lesion. Method Twenty one patients with brain lesion and severe drooling were included and divided into three groups. All patients received conventional dysphagia therapy. Group A patients (n=7) received an injection of 1,500 units and group B patients (n=7) received an injection of 2,500 units of BNT-B in submandibular gland under ultrasound guidance. Group C patients (n=7) received conventional dysphagia therapy. Saliva secretion was assessed quantitatively at baseline and at weeks 1, 2, 4, 8, and 12. The severity and frequency of drooling was assessed using the Drooling Quotient (DQ) by patients and/or caregivers. Results Group A and B reported a distinct improvement of the symptoms within 2 weeks after BNT-B injection. Compared to the baseline, the mean amount of saliva decreased significantly throughout the study. However, there was no meaningful difference between the two groups. The greatest reductions were achieved at 2 weeks and lasted up to 8 weeks after BNT-B injection. Group C did not show any differences. Conclusion Local injection of 1,500 units of BNT-B into salivary glands under ultrasonic guidance proved to be a safe and effective dose for drooling in patient with brain lesion, as did 2,500 units. PMID:23342318

  4. Metal Ion Toxins and Brain Aquaporin-4 Expression: An Overview

    PubMed Central

    Ximenes-da-Silva, Adriana

    2016-01-01

    Metal ions such as iron, zinc, and manganese are essential to metabolic functions, protein synthesis, neurotransmission, and antioxidant neuroprotective mechanisms. Conversely, non-essential metals such as mercury and lead are sources of human intoxication due to occupational activities or environmental contamination. Essential or non-essential metal accumulation in the central nervous system (CNS) results in changes in blood-brain barrier (BBB) permeability, as well as triggering microglia activation and astrocyte reactivity and changing water transport through the cells, which could result in brain swelling. Aquaporin-4 is the main water channel in the CNS, is expressed in astrocyte foot processes in brain capillaries and along the circumventricular epithelium in the ventricles, and has important physiological functions in maintaining brain osmotic homeostasis and supporting brain excitability through regulation of the extracellular space. Some evidence has pointed to a role of AQP4 during metal intoxication in the brain, where it may act in a dual form as a neuroprotector or a mediator of the development of oxidative stress in neurons and astrocytes, resulting in brain swelling and neuronal damage. This mini-review presents the way some metal ions affect changes in AQP4 expression in the CNS and discuss the ways in which water transport in brain cells can be involved in brain damage. PMID:27313504

  5. Metal Ion Toxins and Brain Aquaporin-4 Expression: An Overview.

    PubMed

    Ximenes-da-Silva, Adriana

    2016-01-01

    Metal ions such as iron, zinc, and manganese are essential to metabolic functions, protein synthesis, neurotransmission, and antioxidant neuroprotective mechanisms. Conversely, non-essential metals such as mercury and lead are sources of human intoxication due to occupational activities or environmental contamination. Essential or non-essential metal accumulation in the central nervous system (CNS) results in changes in blood-brain barrier (BBB) permeability, as well as triggering microglia activation and astrocyte reactivity and changing water transport through the cells, which could result in brain swelling. Aquaporin-4 is the main water channel in the CNS, is expressed in astrocyte foot processes in brain capillaries and along the circumventricular epithelium in the ventricles, and has important physiological functions in maintaining brain osmotic homeostasis and supporting brain excitability through regulation of the extracellular space. Some evidence has pointed to a role of AQP4 during metal intoxication in the brain, where it may act in a dual form as a neuroprotector or a mediator of the development of oxidative stress in neurons and astrocytes, resulting in brain swelling and neuronal damage. This mini-review presents the way some metal ions affect changes in AQP4 expression in the CNS and discuss the ways in which water transport in brain cells can be involved in brain damage. PMID:27313504

  6. Insulin signaling disruption in male mice due to perinatal bisphenol A exposure: Role of insulin signaling in the brain.

    PubMed

    Fang, Fangfang; Gao, Yue; Wang, Tingwei; Chen, Donglong; Liu, Jingli; Qian, Wenyi; Cheng, Jie; Gao, Rong; Wang, Jun; Xiao, Hang

    2016-03-14

    Bisphenol A (BPA), an environmental estrogenic endocrine disruptor, is widely used for producing polycarbonate plastics and epoxy resins. Available data have shown that perinatal exposure to BPA contributes to peripheral insulin resistance, while in the present study, we aimed to investigate the effects of perinatal BPA exposure on insulin signaling and glucose transport in the cortex of offspring mice. The pregnant mice were administrated either vehicle or BPA (100 μg/kg/day) at three perinatal stages. Stage I: from day 6 of gestation until parturition (P6-PND0 fetus exposure); Stage II: from lactation until delactation (PND0-PND21 newborn exposure) and Stage III: from day 6 of pregnancy until delactation (P6-PND21 fetus and newborn exposure). At 8 months of age for the offspring mice, the insulin signaling pathways and glucose transporters (GLUTs) were detected. Our data indicated that the insulin signaling including insulin, phosphorylated insulin receptor (IR), phosphorylated protein kinase B (p-AKT), phosphorylated glycogen synthase kinase 3β (p-GSK3β) and phosphorylated extracellular signal regulated protein kinase (p-ERK) were significantly decreased in the brain. In parallel, GLUTs (GLUT1/3/4) were obviously decreased as well in BPA-treated group in mice brain. Noteworthily, the phosphorylated tau (p-tau) and amyloid precursor protein (APP) were markedly up-regulated in all BPA-treated groups. These results, taken together, suggest the adverse effects of BPA on insulin signaling and GLUTs, which might subsequently contribute to the increment of p-tau and APP in the brain of adult offspring. Therefore, perinatal BPA exposure might be a risk factor for the long-term neurodegenerative changes in offspring male mice. PMID:26779933

  7. Insulin signaling disruption in male mice due to perinatal bisphenol A exposure: Role of insulin signaling in the brain.

    PubMed

    Fang, Fangfang; Gao, Yue; Wang, Tingwei; Chen, Donglong; Liu, Jingli; Qian, Wenyi; Cheng, Jie; Gao, Rong; Wang, Jun; Xiao, Hang

    2016-03-14

    Bisphenol A (BPA), an environmental estrogenic endocrine disruptor, is widely used for producing polycarbonate plastics and epoxy resins. Available data have shown that perinatal exposure to BPA contributes to peripheral insulin resistance, while in the present study, we aimed to investigate the effects of perinatal BPA exposure on insulin signaling and glucose transport in the cortex of offspring mice. The pregnant mice were administrated either vehicle or BPA (100 μg/kg/day) at three perinatal stages. Stage I: from day 6 of gestation until parturition (P6-PND0 fetus exposure); Stage II: from lactation until delactation (PND0-PND21 newborn exposure) and Stage III: from day 6 of pregnancy until delactation (P6-PND21 fetus and newborn exposure). At 8 months of age for the offspring mice, the insulin signaling pathways and glucose transporters (GLUTs) were detected. Our data indicated that the insulin signaling including insulin, phosphorylated insulin receptor (IR), phosphorylated protein kinase B (p-AKT), phosphorylated glycogen synthase kinase 3β (p-GSK3β) and phosphorylated extracellular signal regulated protein kinase (p-ERK) were significantly decreased in the brain. In parallel, GLUTs (GLUT1/3/4) were obviously decreased as well in BPA-treated group in mice brain. Noteworthily, the phosphorylated tau (p-tau) and amyloid precursor protein (APP) were markedly up-regulated in all BPA-treated groups. These results, taken together, suggest the adverse effects of BPA on insulin signaling and GLUTs, which might subsequently contribute to the increment of p-tau and APP in the brain of adult offspring. Therefore, perinatal BPA exposure might be a risk factor for the long-term neurodegenerative changes in offspring male mice.

  8. Atlas based brain volumetry: How to distinguish regional volume changes due to biological or physiological effects from inherent noise of the methodology.

    PubMed

    Opfer, Roland; Suppa, Per; Kepp, Timo; Spies, Lothar; Schippling, Sven; Huppertz, Hans-Jürgen

    2016-05-01

    Fully-automated regional brain volumetry based on structural magnetic resonance imaging (MRI) plays an important role in quantitative neuroimaging. In clinical trials as well as in clinical routine multiple MRIs of individual patients at different time points need to be assessed longitudinally. Measures of inter- and intrascanner variability are crucial to understand the intrinsic variability of the method and to distinguish volume changes due to biological or physiological effects from inherent noise of the methodology. To measure regional brain volumes an atlas based volumetry (ABV) approach was deployed using a highly elastic registration framework and an anatomical atlas in a well-defined template space. We assessed inter- and intrascanner variability of the method in 51 cognitively normal subjects and 27 Alzheimer dementia (AD) patients from the Alzheimer's Disease Neuroimaging Initiative by studying volumetric results of repeated scans for 17 compartments and brain regions. Median percentage volume differences of scan-rescans from the same scanner ranged from 0.24% (whole brain parenchyma in healthy subjects) to 1.73% (occipital lobe white matter in AD), with generally higher differences in AD patients as compared to normal subjects (e.g., 1.01% vs. 0.78% for the hippocampus). Minimum percentage volume differences detectable with an error probability of 5% were in the one-digit percentage range for almost all structures investigated, with most of them being below 5%. Intrascanner variability was independent of magnetic field strength. The median interscanner variability was up to ten times higher than the intrascanner variability.

  9. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-11-01

    To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were later confirmed by magnetic resonance imaging at Argonne National Lab and the University of Illinois.

  10. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1990-11-01

    Research continued on the swelling of coal. Changes in the size and number distribution of the accessible regions in five Argonne Premium Coal Samples (APCS No.3, No.4, No.5, No.6, and No.8) upon swelling with the solvents, cyclohexane, toluene, nitrobenzene and pyridine were examined by an EPR spin probe method. It was found that as the basicity of the solvent increased the number and length of the cylindrical pores increased with decreasing rank. The number of cylindrical pores also increased with oxygen content (with decreasing rank) suggesting a destruction of the hydrogen-bond network upon swelling with pyridine. 6 refs.

  11. Learning and generalization deficits in patients with memory impairments due to anterior communicating artery aneurysm rupture or hypoxic brain injury.

    PubMed

    Myers, Catherine E; Hopkins, Ramona O; Hopkins, Romona O; DeLuca, John; Moore, Nancy B; Wolansky, Leo J; Sumner, Jennifer M; Gluck, Mark A

    2008-09-01

    Human anterograde amnesia can result from a variety of etiologies, including hypoxic brain injury and anterior communicating artery (ACoA) aneurysm rupture. Although each etiology can cause a similarly severe disruption in declarative memory for verbal and visual material, there may be differences in incrementally acquired, feedback-based learning, as well as generalization. Here, 6 individuals who survived hypoxic brain injury, 7 individuals who survived ACoA aneurysm rupture, and 13 matched controls were tested on 2 tasks that included a feedback-based learning phase followed by a transfer phase in which familiar information is presented in new ways. In both tasks, the ACoA group was slow on initial learning, but those patients who completed the learning phase went on to transfer as well as controls. In the hypoxic group, 1 patient failed to complete either task; the remaining hypoxic group did not differ from controls during learning of either task, but was impaired on transfer. These results highlight a difference in feedback-based learning in 2 amnesic etiologies, despite similar levels of declarative memory impairment.

  12. Megalencephalic leukoencephalopathy with subcortical cysts: chronic white matter oedema due to a defect in brain ion and water homoeostasis.

    PubMed

    van der Knaap, Marjo S; Boor, Ilja; Estévez, Raúl

    2012-11-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterised by chronic white matter oedema. The disease has an infantile onset and leads to slow neurological deterioration in most cases, but, surprisingly, some patients recover. The first disease gene, MLC1, identified in 2001, is mutated in 75% of patients. At that time, nothing was known about MLC1 protein function and the pathophysiology of MLC. More recently, HEPACAM (also called GLIALCAM) has been identified as a second disease gene. GlialCAM serves as an escort for MLC1 and the chloride channel CLC2. The defect in MLC1 has been shown to hamper the cell volume regulation of astrocytes. One of the most important consequences involves the potassium siphoning process, which is essential in brain ion and water homoeostasis. An understanding of the mechanisms of white matter oedema in MLC is emerging. Further insight into the specific function of MLC1 is necessary to find treatment targets.

  13. A rare cause of lateral facial swelling.

    PubMed

    Mohanty, Sujata; Gulati, Ujjwal; Vandana; Singh, Sapna

    2014-01-01

    A case of chronic, recurrent and asymptomatic facial swelling in a young male is presented. Swelling extended from lower midface to upper lateral neck and right commissure to anterior massetric border. History, clinical signs and symptoms and examination pointed towards the benign nature of the swelling. Fine-needle aspiration cytology tapered the diagnostic possibilities to a salivary cyst or pseudocyst. Ultrasonography identified the lesion to contain echogenic fluid with irregular borders. "Tail sign" was absent on contrast magnetic resonance imaging, excluding the involvement of the sublingual gland. Surgical excision of the lesion was done along with submandibular gland as both were in continuity via a bottle-neck tract. Final histopathological diagnosis was that of the submandibular gland extravasation phenomenon. As per the best of our knowledge, it is the first case report of a submandibular gland extravasation causing swelling in a retrograde direction onto the face. PMID:25593883

  14. A rare cause of lateral facial swelling

    PubMed Central

    Mohanty, Sujata; Gulati, Ujjwal; Vandana; Singh, Sapna

    2014-01-01

    A case of chronic, recurrent and asymptomatic facial swelling in a young male is presented. Swelling extended from lower midface to upper lateral neck and right commissure to anterior massetric border. History, clinical signs and symptoms and examination pointed towards the benign nature of the swelling. Fine-needle aspiration cytology tapered the diagnostic possibilities to a salivary cyst or pseudocyst. Ultrasonography identified the lesion to contain echogenic fluid with irregular borders. “Tail sign” was absent on contrast magnetic resonance imaging, excluding the involvement of the sublingual gland. Surgical excision of the lesion was done along with submandibular gland as both were in continuity via a bottle-neck tract. Final histopathological diagnosis was that of the submandibular gland extravasation phenomenon. As per the best of our knowledge, it is the first case report of a submandibular gland extravasation causing swelling in a retrograde direction onto the face. PMID:25593883

  15. Swelling of lignites in organic solvents

    SciTech Connect

    R.G. Makitra; D.V. Bryk

    2008-10-15

    Data on the swelling of Turkish lignites can be summarized using linear multiparameter equations that take into account various properties of solvents. Factors responsible for the amounts of absorbed solvents are the basicity and cohesion energy density of the solvents.

  16. Climatology of Global Swell-Atmosphere Interaction

    NASA Astrophysics Data System (ADS)

    Semedo, Alvaro

    2016-04-01

    At the ocean surface wind sea and swell waves coexist. Wind sea waves are locally generated growing waves strongly linked to the overlaying wind field. Waves that propagate away from their generation area, throughout entire ocean basins, are called swell. Swell waves do not receive energy from local wind. Ocean wind waves can be seen as the "gearbox" between the atmosphere and the ocean, and are of critical importance to the coupled atmosphere-ocean system, since they modulate most of the air-sea interaction processes and exchanges, particularly the exchange of momentum. This modulation is most of the times sea-state dependent, i.e., it is a function of the prevalence of one type of waves over the other. The wave age parameter, defined as the relative speed between the peak wave and the wind (c_p⁄U_10), has been largely used in different aspects of the air-sea interaction theory and in practical modeling solutions of wave-atmosphere coupled model systems. The wave age can be used to assess the development of the sea state but also the prevalence (domination) of wind sea or swell waves at the ocean surface. The presence of fast-running waves (swell) during light winds (at high wave age regimes) induces an upward momentum flux, directed from the water surface to the atmosphere. This upward directed momentum has an impact in the lower marine atmospheric boundary layer (MABL): on the one hand it changes the vertical wind speed profile by accelerating the flow at the first few meters (inducing the so called "wave-driven wind"), and on the other hand it changes the overall MABL turbulence structure by limiting the wind shear - in some observed and modeled situations the turbulence is said to have "collapse". The swell interaction with the lower MABL is a function of the wave age but also of the swell steepness, since steeper waves loose more energy into the atmosphere as their energy attenuates. This interaction can be seen as highest in areas where swells are steepest

  17. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1991-01-01

    The EPR-spin probe method was used to study the swelling of covalently cross-linked 2%, 4%, 6%, 8% and 12% polystyrene-divinyl benzene copolymers, used as models of APCS coal structural elements. The results were compared with swelling studies on APCS coals and confirmed results showing that coal was polymeric, that it had covalent cross-links increasing with rank, that it was structurally anisotropic, and that its swelling was anisotropic. The low temperature swelling of Argonne Premium Coal Samples using solvents of varying polarity was investigated. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities. The structural changes in coal pores that occur when APCS coal is dehydrated prior to swelling with polar solvents has been determined. These changes are different from those that occur in the absence of prior dehydration. Most impressive is the huge change that occurs in lignite coal (Beulah-Zap). It appears that this coal has collapsed upon dehydration preventing any spin probe from being trapped in the dehydrated lignite upon swelling. Various sized probes have been studied. A study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents has also been completed. A statistical analysis of the data has been completed to determine important trends in the data. 9 refs.

  18. Swelling kinetics of tea in hot water.

    PubMed

    Joshi, Bhushan S; Farakte, Raosaheb A; Yadav, Geeta U; Patwardhan, Ashwin W; Singh, Gurmeet

    2016-01-01

    In this study, the swelling kinetics of individual tea particles as well as bed of tea granules were investigated for different types of teas. The swelling experiments involved image analysis and volume measurements of tea particles. Each individual particle shows different swelling characteristics. Separating funnels and cylindrical columns of varying sizes were used to study the changes in volume of tea bed. Swelling in separating funnel was observed to be more than that in column. The effect of temperature, particle size, bed height and vessel diameter were investigated. The extent as well as the rate of swelling is found to increase with rise in temperature (60 to 80 °C) and reduction in particle size. A decrease in swelling is observed with increase in bed height as well as decrease in vessel diameter and vice a versa. About 70 to 75 % swelling occurs in the first 40 to 45 s. Two empirical models viz. Weibull and Peleg were used to fit the experimental data. The rate parameters obtained for a sample T5 at different temperatures were in the range of 0.012 to 0.016. The volume changes of all the teas were compared with their elution behavior, by measuring the absorbance of a diluted sample of brew at 272 nm. The activation energies for the process of tea swelling calculated for T1 (1.2 mm), T5 (2.2 mm) and T5 (0.72 mm) were 14.156, 8.37 and 13.42 kJ/mol respectively. PMID:26787951

  19. An unusual case of acute periorbital swelling.

    PubMed

    Torretta, Sara; Brevi, Alessandra; Pagani, Davide; Pignataro, Lorenzo

    2014-01-01

    Periorbital swelling is frequently encountered in ear, nose, and throat practices and, as it may be secondary to acute sinusitis, delayed diagnosis may lead to significant morbidity. We describe the case of a 24-year-old man with acute ethmoid-maxillary sinusitis and ipsilateral facial swelling particularly involving the periorbital area. We also discuss the workup that led to the formulation of an unusual diagnosis.

  20. Secretory vesicle swelling by atomic force microscopy.

    PubMed

    Cho, Sang-Joon; Jena, Bhanu P

    2006-01-01

    The swelling of secretory vesicles has been implicated in exocytosis, but the underlying mechanism of vesicle swelling remained unknown. Earlier studies from our laboratory demonstrated the association of the alpha-subunit of heterotrimeric GTP-binding protein G(alphai3) with zymogen granule membrane and implicated its involvement in vesicle swelling. Mas7, an active mastoparan analog known to stimulate Gi proteins, was found to stimulate the GTPase activity of isolated zymogen granules and cause swelling. Increase in vesicle size in the presence of GTP, NaF, and Mas7 were irreversible and found to be KCl sensitive. However, Ca2+ had no effect on zymogen granule size. Taken together, these results indicated that zymogen granules, the membrane-bound secretory vesicles in exocrine pancreas, swell in response to GTP mediated by a G(alphai3) protein. Subsequently, our studies demonstrated that the water channel aquaporin-1 (AQP1) is also present at the zymogen granule membrane and participates in rapid GTP-induced and G(alphai3)-mediated vesicular water gating and swelling. Isolated zymogen granules exhibit low basal water permeability. However, exposure of granules to GTP results in a marked potentiation of water entry. Treatment of zymogen granules with the known water channel inhibitor Hg2+ is accompanied by a reversible loss in both the basal and GTP-stimulable water entry and vesicle swelling. Introduction of AQP1-specific antibody raised against the carboxy-terminal domain of AQP1 blocked GTP-stimulable swelling of vesicles. Our results demonstrate that AQPI associated at the zymogen granule membrane is involved in basal GTP-induced and G(alphai3)-mediated rapid gating of water into zymogen granules of the exocrine pancreas.

  1. Swelling kinetics of tea in hot water.

    PubMed

    Joshi, Bhushan S; Farakte, Raosaheb A; Yadav, Geeta U; Patwardhan, Ashwin W; Singh, Gurmeet

    2016-01-01

    In this study, the swelling kinetics of individual tea particles as well as bed of tea granules were investigated for different types of teas. The swelling experiments involved image analysis and volume measurements of tea particles. Each individual particle shows different swelling characteristics. Separating funnels and cylindrical columns of varying sizes were used to study the changes in volume of tea bed. Swelling in separating funnel was observed to be more than that in column. The effect of temperature, particle size, bed height and vessel diameter were investigated. The extent as well as the rate of swelling is found to increase with rise in temperature (60 to 80 °C) and reduction in particle size. A decrease in swelling is observed with increase in bed height as well as decrease in vessel diameter and vice a versa. About 70 to 75 % swelling occurs in the first 40 to 45 s. Two empirical models viz. Weibull and Peleg were used to fit the experimental data. The rate parameters obtained for a sample T5 at different temperatures were in the range of 0.012 to 0.016. The volume changes of all the teas were compared with their elution behavior, by measuring the absorbance of a diluted sample of brew at 272 nm. The activation energies for the process of tea swelling calculated for T1 (1.2 mm), T5 (2.2 mm) and T5 (0.72 mm) were 14.156, 8.37 and 13.42 kJ/mol respectively.

  2. Expression of S100A6 in Rat Hippocampus after Traumatic Brain Injury Due to Lateral Head Acceleration

    PubMed Central

    Fang, Bo; Liang, Ming; Yang, Guitao; Ye, Yuqin; Xu, Hongyu; He, Xiaosheng; Huang, Jason H.

    2014-01-01

    In a rat model of traumatic brain injury (TBI), we investigated changes in cognitive function and S100A6 expression in the hippocampus. TBI-associated changes in this protein have not previously been reported. Rat S100A6 was studied via immunohistochemical staining, Western blot, and reverse transcription-polymerase chain reaction (RT-PCR) after either lateral head acceleration or sham. Reduced levels of S100A6 protein and mRNA were observed 1 h after TBI, followed by gradual increases over 6, 12, 24, and 72 h, and then a return to sham level at 14 day. Morris water maze (MWM) test was used to evaluate animal spatial cognition. TBI- and sham-rats showed an apparent learning curve, expressed as escape latency. Although TBI-rats displayed a relatively poorer cognitive ability than sham-rats, the disparity was not significant early post-injury. Marked cognitive deficits in TBI-rats were observed at 72 h post-injury compared with sham animals. TBI-rats showed decreased times in platform crossing in the daily MWM test; the performance at 72 h post-injury was the worst. In conclusion, a reduction in S100A6 may be one of the early events that lead to secondary cognitive decline after TBI, and its subsequent elevation is tightly linked with cognitive improvement. S100A6 may play important roles in neuronal degeneration and regeneration in TBI. PMID:24739809

  3. Estimates of the eigenvalues of operator arising in swelling pressure model

    NASA Astrophysics Data System (ADS)

    Kanguzhin, Baltabek; Zhapsarbayeva, Lyailya

    2016-08-01

    Swelling pressures from materials confined by structures can cause structural deformations and instability. Due to the complexity of interactions between expansive solid and solid-liquid equilibrium, the forces exerting on retaining structures from swelling are highly nonlinear. This work is our initial attempt to study a simplistic spectral problem based on the Euler-elastic beam theory and some simplistic swelling pressure model. In this work estimates of the eigenvalues of some initial/boundary value problem for nonlinear Euler-elastic beam equation are obtained.

  4. Green tea polyphenols attenuate glial swelling and mitochondrial dysfunction following oxygen-glucose deprivation in cultures.

    PubMed

    Panickar, Kiran S; Polansky, Marilyn M; Anderson, Richard A

    2009-06-01

    Astrocyte swelling is a major component of cytotoxic brain edema in ischemia. Oxidative stress and mitochondrial dysfunction have been hypothesized to contribute to such swelling in cultures. We investigated the protective effects of polyphenol-rich green tea extract (GTE) on key features of ischemic injury namely cell swelling, nitric oxide (NO) production, and depolarization of the inner mitochondrial membrane potential (Deltapsi(m)). C6 glial cultures were subjected to 5-h oxygen-glucose deprivation (OGD) and cell volume was determined using the 3-O-methyl-glucose method. At 90 min after the end of OGD, cell volume increased by > 33% and this increase was attenuated by GTE but not by the individual polyphenol components including catechin, epicatechin, or epigallocatechin gallate (EGCG). However, a combination of catechin, epicatechin and EGCG prevented swelling. OGD-induced increase in NO was further increased by GTE. OGD-induced decline in Deltapsi(m) was also attenuated by green tea extract, EGCG and a combination of catechin, epicatechin and EGCG but not by catechin or epicatechin alone. Our findings indicate a protective effect of GTE in cell swelling in ischemic injury and such protective effects may be mediated by its effect on the mitochondria. It appears that effects on cell swelling are mediated by the concerted action of more than one of the individual components of GTE.

  5. Increased susceptibility of transgenic mice expressing human PrP to experimental sheep bovine spongiform encephalopathy is not due to increased agent titre in sheep brain tissue.

    PubMed

    Plinston, Chris; Hart, Patricia; Hunter, Nora; Manson, Jean C; Barron, Rona M

    2014-08-01

    Bovine spongiform encephalopathy (BSE) in cattle and variant Creutzfeldt-Jakob disease in humans have previously been shown to be caused by the same strain of transmissible spongiform encephalopathy agent. It is hypothesized that the agent spread to humans following consumption of food products prepared from infected cattle. Despite evidence supporting zoonotic transmission, mouse models expressing human prion protein (HuTg) have consistently shown poor transmission rates when inoculated with cattle BSE. Higher rates of transmission have however been observed when these mice are exposed to BSE that has been experimentally transmitted through sheep or goats, indicating that humans may potentially be more susceptible to BSE from small ruminants. Here we demonstrate that increased transmissibility of small ruminant BSE to HuTg mice was not due to replication of higher levels of infectivity in sheep brain tissue, and is instead due to other specific changes in the infectious agent.

  6. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1991-08-01

    Research continued on the determination of pore size and number distribution changes after swelling the coal samples with various solvents. A paper has just been submitted to the journal Fuel on the Low temperature Swelling of Argonne Premium Coal samples using solvents of varying polarity. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities. A copy of this paper has been attached to this report. Wojciech Sady has determine the structural changes in the pores that occur when APCS coal is dehydrated prior to swelling with polar solvents. These changes are different from those that occur in the absence of prior dehydration. He has also completed a study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents. A statistical analysis of the data is currently underway to determine important trends in his data. 9 refs.

  7. Morphing of geometric composites via residual swelling.

    PubMed

    Pezzulla, Matteo; Shillig, Steven A; Nardinocchi, Paola; Holmes, Douglas P

    2015-08-01

    Understanding and controlling the shape of thin, soft objects has been the focus of significant research efforts among physicists, biologists, and engineers in the last decade. These studies aim to utilize advanced materials in novel, adaptive ways such as fabricating smart actuators or mimicking living tissues. Here, we present the controlled growth-like morphing of 2D sheets into 3D shapes by preparing geometric composite structures that deform by residual swelling. The morphing of these geometric composites is dictated by both swelling and geometry, with diffusion controlling the swelling-induced actuation, and geometric confinement dictating the structure's deformed shape. Building on a simple mechanical analog, we present an analytical model that quantitatively describes how the Gaussian and mean curvatures of a thin disk are affected by the interplay among geometry, mechanics, and swelling. This model is in excellent agreement with our experiments and numerics. We show that the dynamics of residual swelling is dictated by a competition between two characteristic diffusive length scales governed by geometry. Our results provide the first 2D analog of Timoshenko's classical formula for the thermal bending of bimetallic beams - our generalization explains how the Gaussian curvature of a 2D geometric composite is affected by geometry and elasticity. The understanding conferred by these results suggests that the controlled shaping of geometric composites may provide a simple complement to traditional manufacturing techniques. PMID:26076671

  8. Swelling and Contraction of Corn Mitochondria 1

    PubMed Central

    Stoner, C. D.; Hanson, J. B.

    1966-01-01

    A survey has been made of the properties of corn mitochondria in swelling and contraction. The mitochondria swell spontaneously in KCl but not in sucrose. Aged mitochondria will swell rapidly in sucrose if treated with citrate or EDTA. Swelling does not impair oxidative phosphorylation if bovine serum albumin is present. Contraction can be maintained or initiated with ATP + Mg or an oxidizable substrate, contraction being more rapid with the substrate. Magnesium is not required for substrate powered contraction. Contraction powered by ATP is accompanied by the release of phosphate. Oligomycin inhibits both ATP-powered contraction and the release of phosphate. However, it does not affect substrate-powered contraction. Substrate powered contraction is inhibited by electron-transport inhibitors. The uncoupler, carbonyl cyanide m-chlorophenyl hydrazone, accelerates swelling and inhibits both ATP-and substrate-powered contraction. However, the concentrations required are well in excess of those required to produce uncoupling and to accelerate adenosine triphosphatase; the concentrations required inhibit respiration in a phosphorylating medium. Phosphate is a very effective inhibitor of succinate-powered contraction. Neither oligomycin nor Mg affects the phosphate inhibition. Phosphate is less inhibitory with the ATP-powered contraction. The results are discussed in terms of a hypothesis that contraction is associated with a nonphosphorylated high energy intermediate of oxidative phosphorylation. Images PMID:16656248

  9. Swelling effect actuation of shape-memory polymer: mechanism and demonstration

    NASA Astrophysics Data System (ADS)

    Lu, Haibao; Leng, Jinsong; Liu, Yanju; Du, Shanyi

    2009-03-01

    Recently, there is increasing interest in triggering shape recovery of shape-memory polymers (SMPs) by novel inductive effect. In this paper, many hard works have been carried out to make SMP induced while along with swelling effect. Based on the Free-volume theory, Rubber Elasticity Theory and Mooney-Rivlin Equation, it is theoretically and experimentally demonstrated the feasibility of SMP activated by swelling effect. The mechanism behind it is solvent acting as plasticizer, to reduce the glass transition temperature (Tg) and melting temperature (Tm) of polymers, make them softer and more flexible, facilitating the diffusion of the molecules to polymer chains, and then separating them. In addition to this physical action, the intermolecular interactions among the chains are weakened, because interactions are hindered at the points where the plasticizer is located. Finally, the Dynamic mechanical analysis (DMA), FTIR study and glass transition temperature measurement tests were used to exemplify the feasibility of SMP driven by swelling effect. And it is qualitatively identified the role of swelling effect playing in influencing the transition temperature. Swelling effect occurs due to the interaction between macromolecules and solvent molecules, leading to free volume of polymeric chains increasing (namely the flexibility of polymer chains increasing), resulting in the Tg decreasing. All above mentioned investigation can be used to confirm that the shape recovery is induced by swelling effect. This actuation almost is applicable for all the SMP and SMP composite, as the swelling theory is almost applicable for all the polymeric materials.

  10. Swelling pressure of a divalent-rich bentonite: Diffuse double-layer theory revisited

    NASA Astrophysics Data System (ADS)

    Schanz, Tom; Tripathy, Snehasis

    2009-05-01

    Physicochemical forces are responsible for the swelling pressure development in saturated bentonites. In this paper, the swelling pressures of several compacted bentonite specimens for a range of dry density of 1.10-1.73 Mg/m3 were measured experimentally. The clay used was a divalent-rich Ca-Mg-bentonite with 12% exchangeable Na+ ions. The theoretical swelling pressure-dry density relationship for the bentonite was determined from the Gouy-Chapman diffuse double-layer theory. A comparison of experimental and theoretical results showed that the experimental swelling pressures are either smaller or greater than their theoretical counterparts within different dry density ranges. It is shown that for dry density of the clay less than about 1.55 Mg/m3, a possible dissociation of ions from the surface of the clay platelets contributed to the diffuse double-layer repulsion. At higher dry densities, the adsorptive forces due to surface and ion hydration dominated the swelling pressures of the clay. A comparison of the modified diffuse double-layer theory equations proposed in the literature to determine the swelling pressures of compacted bentonites and the experimental results for the clay in this study showed that the agreement between the calculated and experimental swelling pressure results is very good for dry densities less than 1.55 Mg/m3, whereas at higher dry densities the use of the equations was found to be limited.

  11. Swelling, mechanical and friction properties of PVA/PVP hydrogels after swelling in osmotic pressure solution.

    PubMed

    Shi, Yan; Xiong, Dangsheng; Liu, Yuntong; Wang, Nan; Zhao, Xiaoduo

    2016-08-01

    The potential of polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) hydrogels as articular cartilage replacements was in vitro evaluated by using a macromolecule-based solution to mimic the osmotic environment of cartilage tissue. The effects of osmotic pressure solution on the morphology, crystallinity, swelling, mechanical and friction properties of PVA/PVP hydrogels were investigated by swelling them in non-osmotic and osmotic pressure solutions. The results demonstrated that swelling ratio and equilibrium water content were greatly reduced by swelling in osmotic solution, and the swelling process was found to present pseudo-Fickian diffusion character. The crystallization degree of hydrogels after swelling in osmotic solution increased more significantly when it compared with that in non-osmotic solution. After swelling in osmotic solution for 28days, the compressive tangent modulus and storage modulus of hydrogels were significantly increased, and the low friction coefficient was reduced. However, after swelling in the non-osmotic solution, the compressive tangent modulus and friction coefficient of hydrogels were comparable with those of as-prepared hydrogels. The better material properties of hydrogels in vivo than in vitro evaluation demonstrated their potential application in cartilage replacement.

  12. Swelling of pH-sensitive hydrogels.

    PubMed

    Drozdov, A D; deClaville Christiansen, J

    2015-02-01

    A model is derived for the elastic response of polyelectrolyte gels subjected to unconstrained and constrained swelling. A gel is treated as a three-phase medium consisting of a solid phase (polymer network), solvent (water), and solutes (mobile ions). Transport of solvent and solutes is modeled as their diffusion through the network accelerated by an electric field formed by ions and accompanied by chemical reactions (dissociation of functional groups attached to the chains). Constitutive equations (including the van't Hoff law for ionic pressure and the Henderson-Hasselbach equation for ionization of chains) are derived by means of the free energy imbalance inequality. Good agreement is demonstrated between equilibrium swelling diagrams on several pH-sensitive gels and results of simulation. It is revealed that swelling of polyelectrolyte gels is driven by electrostatic repulsion of bound charges, whereas the effect of ionic pressure is of secondary importance. PMID:25768503

  13. Swelling of p H -sensitive hydrogels

    NASA Astrophysics Data System (ADS)

    Drozdov, A. D.; deClaville Christiansen, J.

    2015-02-01

    A model is derived for the elastic response of polyelectrolyte gels subjected to unconstrained and constrained swelling. A gel is treated as a three-phase medium consisting of a solid phase (polymer network), solvent (water), and solutes (mobile ions). Transport of solvent and solutes is modeled as their diffusion through the network accelerated by an electric field formed by ions and accompanied by chemical reactions (dissociation of functional groups attached to the chains). Constitutive equations (including the van't Hoff law for ionic pressure and the Henderson-Hasselbach equation for ionization of chains) are derived by means of the free energy imbalance inequality. Good agreement is demonstrated between equilibrium swelling diagrams on several pH-sensitive gels and results of simulation. It is revealed that swelling of polyelectrolyte gels is driven by electrostatic repulsion of bound charges, whereas the effect of ionic pressure is of secondary importance.

  14. Evaluating the geochemically induced swelling/shrinkage of the near-field host clay rock using a THC model and the diffuse double layer theory

    NASA Astrophysics Data System (ADS)

    Zheng, L.; Liu, H.; Birkholzer, J. T.; Houseworth, J. E.; Sonnenthal, E. L.

    2011-12-01

    One advantage of emplacing nuclear waste in a clay formation is the potential self-sealing capability due to clay swelling. The swelling properties of the near-field host clay rock can be altered due to geochemical factors, including changes in groundwater geochemistry, proportions of exchangeable cations, and swelling clay mineral abundances. The clay host rock can also undergo geochemical changes due to the interaction with the engineered barrier system (EBS) materials. In this paper, coupled thermal, hydrological, and chemical (THC) models are linked with a swelling model based on diffuse double layer (DDL) theory and changes in the swelling properties of clay host rocks in the near field area are evaluated. Findings based on THC simulations using the reaction-transport code TOUGHREACT include: 1) Significant changes in the swelling pressure could be expected depending on various hydrogeologic and geochemical conditions. The change of hydration rate of the EBS (via the adjustment of tortuosity) could have significant effect on the swelling pressure. 2) Geochemically-induced swelling/shrinkage only occurs in the near-field area, within a few meters from the EBS interface. 3) Swelling/shrinkage induced porosity change is generally much smaller than that caused by mineral precipitation/dissolution. 4) The geochemically-induced swelling/shrinkage of host clay rock is the combined effect of variation in the pore water geochemistry, exchangeable cations, and smectite abundance. Neglecting any of these three latter factors might lead to a miscalculation of the geochemically-induced swelling pressure.

  15. NMR imaging and cryoporometry of swelling clays

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey V.; Szutkowski, Kosma; Petrov, Oleg V.; Furó, István.

    2010-05-01

    Compacted bentonite clay is currently attracting attention as a promising "self-sealing" buffer material to build in-ground barriers for the encapsulation of radioactive waste. It is expected to fill up the space between waste canister and surrounding ground by swelling and thus delay flow and migration from the host rock to the canister. In environmental sciences, evaluation and understanding of the swelling properties of pre-compacted clay are of uttermost importance for designing such buffers. Major goal of present study was to provide, in a non-invasive manner, a quantitative measure of bentonite distribution in extended samples during different physical processes in an aqueous environment such as swelling, dissolution, and sedimentation on the time scale from minutes to years. The propagation of the swelling front during clay expansion depending on the geometry of the confining space was also studied. Magnetic resonance imaging and nuclear magnetic resonance spectroscopy were adapted and used as main experimental techniques. With this approach, spatially resolved movement of the clay/water interface as well as clay particle distributions in gel phase can be monitored [1]. Bulk samples with swelling in a vertical tube and in a horizontal channel were investigated and clay content distribution profiles in the concentration range over five orders of magnitude and with sub-millimetre spatial resolution were obtained. Expansion rates for bulk swelling and swelling in narrow slits were compared. For sodium-exchanged montmorillonite in contact with de-ionised water, we observed a remarkable acceleration of expansion as compared to that obtained in the bulk. To characterize the porosity of the clay a cryoporometric study [2] has been performed. Our results have important implications to waste repository designs and for the assessment of its long-term performance. Further research exploring clay-water interaction over a wide variety of clay composition and water ionic

  16. Swelling of plasma-polymerized tetrafluoroethylene films

    SciTech Connect

    Butler, M.A.; Buss, R.J.; Seager, C.H. )

    1991-11-25

    Swelling of micrometer thick-films of plasma-polymerized tetrafluoroethylene has been measured for a range of solvents using an optical-interferometric technique. For low gas-phase concentrations of the solvent, the swelling is found to correlate with the ionization potential of the solvent. Photo-thermal deflection spectroscopy of the films shows optical absorption in the infrared, which changes with exposure to different solvents. Both of these results suggest weak electron transfer from the solvent to the polymer as the dominant interaction mechanism.

  17. Characteristic changes in brain electrical activity due to chronic hypoxia in patients with obstructive sleep apnea syndrome (OSAS): a combined EEG study using LORETA and omega complexity.

    PubMed

    Toth, Marton; Faludi, Bela; Wackermann, Jiri; Czopf, Jozsef; Kondakor, Istvan

    2009-11-01

    EEG background activity of patients with obstructive sleep apnea syndrome (OSAS, N = 25) was compared to that of normal controls (N = 14) to reflect alterations of brain electrical activity caused by chronic intermittent hypoxia in OSAS. Global and regional (left vs. right, anterior vs. posterior) measures of spatial complexity (Omega) were used to characterize the degree of spatial synchrony of EEG. Low resolution electromagnetic tomography (LORETA) was used to localize generators of EEG activity in separate frequency bands. Comparing patients to controls, lower Omega complexity was found globally and in the right hemisphere. Using LORETA, an increased medium frequency activity was seen bilaterally in the precuneus, paracentral and posterior cingulate cortex. These findings indicate that alterations caused by chronic hypoxia in brain electrical activity in regions associated with influencing emotional regulation, long-term memory and the default mode network. Global synchronization (lower Omega complexity) may indicate a significantly reduced number of relatively independent, parallel neural processes due to chronic global hypoxic state in apneic patients as well as over the right hemisphere.

  18. Subconjuctival Loa loa with Calabar swelling.

    PubMed

    Cho, Hee-Yoon; Lee, Yoon-Jung; Shin, Sun-Young; Song, Hyun-Ouk; Ahn, Myoung-Hee; Ryu, Jae-Sook

    2008-08-01

    Loa loa is unique among the human filariae in that adult worms are occasionally visible during subconjunctival migration. A 29-yr-old African female student, living in Korea for the past 5 yr without ever visiting her home country, presented with acute eyelid swelling and a sensation of motion on the left eyeball. Her symptoms started one day earlier and became worse over time. Examination revealed a threadlike worm beneath the left upper bulbar conjunctiva with mild eyelid swelling as well as painless swelling of the right forearm. Upon exposure to slit-lamp illumination, a sudden movement of the worm toward the fornix was noted. After surgical extraction, parasitologic analysis confirmed the worm to be a female adult Loa loa with the vulva at the extreme anterior end. On blood smear, the microfilariae had characteristic features of Loa loa, including sheath and body nuclei up to the tip of the tail. The patient also showed eosinophilia (37%) measuring 4,100/microL. She took ivermectin (200 microg/kg) as a single dose and suffered from a mild fever and chills for one day. This patient, to the best of our knowledge, is the first case of subconjunctival loiasis with Calabar swelling in Korea. PMID:18756067

  19. Assessment of the structural brain network reveals altered connectivity in children with unilateral cerebral palsy due to periventricular white matter lesions

    PubMed Central

    Pannek, Kerstin; Boyd, Roslyn N.; Fiori, Simona; Guzzetta, Andrea; Rose, Stephen E.

    2014-01-01

    Background Cerebral palsy (CP) is a term to describe the spectrum of disorders of impaired motor and sensory function caused by a brain lesion occurring early during development. Diffusion MRI and tractography have been shown to be useful in the study of white matter (WM) microstructure in tracts likely to be impacted by the static brain lesion. Aim The purpose of this study was to identify WM pathways with altered connectivity in children with unilateral CP caused by periventricular white matter lesions using a whole-brain connectivity approach. Methods Data of 50 children with unilateral CP caused by periventricular white matter lesions (5–17 years; manual ability classification system [MACS] I = 25/II = 25) and 17 children with typical development (CTD; 7–16 years) were analysed. Structural and High Angular Resolution Diffusion weighted Images (HARDI; 64 directions, b = 3000 s/mm2) were acquired at 3 T. Connectomes were calculated using whole-brain probabilistic tractography in combination with structural parcellation of the cortex and subcortical structures. Connections with altered fractional anisotropy (FA) in children with unilateral CP compared to CTD were identified using network-based statistics (NBS). The relationship between FA and performance of the impaired hand in bimanual tasks (Assisting Hand Assessment—AHA) was assessed in connections that showed significant differences in FA compared to CTD. Results FA was reduced in children with unilateral CP compared to CTD. Seven pathways, including the corticospinal, thalamocortical, and fronto-parietal association pathways were identified simultaneously in children with left and right unilateral CP. There was a positive relationship between performance of the impaired hand in bimanual tasks and FA within the cortico-spinal and thalamo-cortical pathways (r2 = 0.16–0.44; p < 0.05). Conclusion This study shows that network-based analysis of structural connectivity can identify alterations

  20. Anions Govern Cell Volume: A Case Study of Relative Astrocytic and Neuronal Swelling in Spreading Depolarization

    PubMed Central

    2016-01-01

    Cell volume changes are ubiquitous in normal and pathological activity of the brain. Nevertheless, we know little about the dynamics of cell and tissue swelling, and the differential changes in the volumes of neurons and glia during pathological states such as spreading depolarizations (SD) under ischemic and non–ischemic conditions, and epileptic seizures. By combining the Hodgkin–Huxley type spiking dynamics, dynamic ion concentrations, and simultaneous neuronal and astroglial volume changes into a comprehensive model, we elucidate why glial cells swell more than neurons in SD and the special case of anoxic depolarization (AD), and explore the relative contributions of the two cell types to tissue swelling. Our results demonstrate that anion channels, particularly Cl−, are intrinsically connected to cell swelling and blocking these currents prevents changes in cell volume. The model is based on a simple and physiologically realistic description. We introduce model extensions that are either derived purely from first physical principles of electroneutrality, osmosis, and conservation of particles, or by a phenomenological combination of these principles and known physiological facts. This work provides insights into numerous studies related to neuronal and glial volume changes in SD that otherwise seem contradictory, and is broadly applicable to swelling in other cell types and conditions. PMID:26974767

  1. Anions Govern Cell Volume: A Case Study of Relative Astrocytic and Neuronal Swelling in Spreading Depolarization.

    PubMed

    Hübel, Niklas; Ullah, Ghanim

    2016-01-01

    Cell volume changes are ubiquitous in normal and pathological activity of the brain. Nevertheless, we know little about the dynamics of cell and tissue swelling, and the differential changes in the volumes of neurons and glia during pathological states such as spreading depolarizations (SD) under ischemic and non-ischemic conditions, and epileptic seizures. By combining the Hodgkin-Huxley type spiking dynamics, dynamic ion concentrations, and simultaneous neuronal and astroglial volume changes into a comprehensive model, we elucidate why glial cells swell more than neurons in SD and the special case of anoxic depolarization (AD), and explore the relative contributions of the two cell types to tissue swelling. Our results demonstrate that anion channels, particularly Cl-, are intrinsically connected to cell swelling and blocking these currents prevents changes in cell volume. The model is based on a simple and physiologically realistic description. We introduce model extensions that are either derived purely from first physical principles of electroneutrality, osmosis, and conservation of particles, or by a phenomenological combination of these principles and known physiological facts. This work provides insights into numerous studies related to neuronal and glial volume changes in SD that otherwise seem contradictory, and is broadly applicable to swelling in other cell types and conditions.

  2. Anions Govern Cell Volume: A Case Study of Relative Astrocytic and Neuronal Swelling in Spreading Depolarization.

    PubMed

    Hübel, Niklas; Ullah, Ghanim

    2016-01-01

    Cell volume changes are ubiquitous in normal and pathological activity of the brain. Nevertheless, we know little about the dynamics of cell and tissue swelling, and the differential changes in the volumes of neurons and glia during pathological states such as spreading depolarizations (SD) under ischemic and non-ischemic conditions, and epileptic seizures. By combining the Hodgkin-Huxley type spiking dynamics, dynamic ion concentrations, and simultaneous neuronal and astroglial volume changes into a comprehensive model, we elucidate why glial cells swell more than neurons in SD and the special case of anoxic depolarization (AD), and explore the relative contributions of the two cell types to tissue swelling. Our results demonstrate that anion channels, particularly Cl-, are intrinsically connected to cell swelling and blocking these currents prevents changes in cell volume. The model is based on a simple and physiologically realistic description. We introduce model extensions that are either derived purely from first physical principles of electroneutrality, osmosis, and conservation of particles, or by a phenomenological combination of these principles and known physiological facts. This work provides insights into numerous studies related to neuronal and glial volume changes in SD that otherwise seem contradictory, and is broadly applicable to swelling in other cell types and conditions. PMID:26974767

  3. A structural model for the in vivo human cornea including collagen-swelling interaction.

    PubMed

    Cheng, Xi; Petsche, Steven J; Pinsky, Peter M

    2015-08-01

    A structural model of the in vivo cornea, which accounts for tissue swelling behaviour, for the three-dimensional organization of stromal fibres and for collagen-swelling interaction, is proposed. Modelled as a binary electrolyte gel in thermodynamic equilibrium, the stromal electrostatic free energy is based on the mean-field approximation. To account for active endothelial ionic transport in the in vivo cornea, which modulates osmotic pressure and hydration, stromal mobile ions are shown to satisfy a modified Boltzmann distribution. The elasticity of the stromal collagen network is modelled based on three-dimensional collagen orientation probability distributions for every point in the stroma obtained by synthesizing X-ray diffraction data for azimuthal angle distributions and second harmonic-generated image processing for inclination angle distributions. The model is implemented in a finite-element framework and employed to predict free and confined swelling of stroma in an ionic bath. For the in vivo cornea, the model is used to predict corneal swelling due to increasing intraocular pressure (IOP) and is adapted to model swelling in Fuchs' corneal dystrophy. The biomechanical response of the in vivo cornea to a typical LASIK surgery for myopia is analysed, including tissue fluid pressure and swelling responses. The model provides a new interpretation of the corneal active hydration control (pump-leak) mechanism based on osmotic pressure modulation. The results also illustrate the structural necessity of fibre inclination in stabilizing the corneal refractive surface with respect to changes in tissue hydration and IOP. PMID:26156299

  4. A structural model for the in vivo human cornea including collagen-swelling interaction

    PubMed Central

    Cheng, Xi; Petsche, Steven J.; Pinsky, Peter M.

    2015-01-01

    A structural model of the in vivo cornea, which accounts for tissue swelling behaviour, for the three-dimensional organization of stromal fibres and for collagen-swelling interaction, is proposed. Modelled as a binary electrolyte gel in thermodynamic equilibrium, the stromal electrostatic free energy is based on the mean-field approximation. To account for active endothelial ionic transport in the in vivo cornea, which modulates osmotic pressure and hydration, stromal mobile ions are shown to satisfy a modified Boltzmann distribution. The elasticity of the stromal collagen network is modelled based on three-dimensional collagen orientation probability distributions for every point in the stroma obtained by synthesizing X-ray diffraction data for azimuthal angle distributions and second harmonic-generated image processing for inclination angle distributions. The model is implemented in a finite-element framework and employed to predict free and confined swelling of stroma in an ionic bath. For the in vivo cornea, the model is used to predict corneal swelling due to increasing intraocular pressure (IOP) and is adapted to model swelling in Fuchs' corneal dystrophy. The biomechanical response of the in vivo cornea to a typical LASIK surgery for myopia is analysed, including tissue fluid pressure and swelling responses. The model provides a new interpretation of the corneal active hydration control (pump-leak) mechanism based on osmotic pressure modulation. The results also illustrate the structural necessity of fibre inclination in stabilizing the corneal refractive surface with respect to changes in tissue hydration and IOP. PMID:26156299

  5. Numerical and Experimental Studies on Extrudate Swell of Linear and Branched Polyethylenes

    NASA Astrophysics Data System (ADS)

    Ganvir, Vivek; Gautham, B. P.; Thaokar, Rochish; Lele, Ashish

    2008-07-01

    Extrudate swell is a common phenomenon observed by the polymer extrusion industry. Accurate prediction of extrudate swell in polymer melt extrusion is important as this helps in appropriate extrudate design for profile extrusion applications. Extrudate swell prediction has shown significant difficulties due to two key reasons. The first is the appropriate representation of the constitutive behavior of the polymer melt. The second is regarding the simulation of the free surface, which requires special techniques in the traditionally used Eulerian framework. We have simulated extrudate swell using an Arbitrary Lagrangian Eulerian (ALE) technique based finite element formulation and the same has been validated by comparing the results with reported numerical and experimental studies. In the present work we compare our ALE simulations with our own experimental data on the extrudate swell of commercial grade HDPE, LLDPE and LDPE resins. The resins were characterized for their rheological behavior in both shear and uniaxial extension. The polymers were extruded from a capillary under isothermal conditions and the extrudates were observed on-line using a video camera. ALE simulations were performed using PTT model for linear (HDPE) polymer melts and eXtended Pom-Pom (XPP) model for branched (LDPE). The simulated extrudate swell showed good match with the experimental data.

  6. Dynamic swelling behavior of interpenetrating polymer networks in response to temperature and pH

    PubMed Central

    Slaughter, Brandon V.; Blanchard, Aaron T.; Maass, Katie F.; Peppas, Nicholas A.

    2015-01-01

    Temperature responsive hydrogels based on ionic polymers exhibit swelling transitions in aqueous solutions as a function of shifting pH and ionic strength, in addition to temperature. Applying these hydrogels to useful applications, particularly for biomedical purposes such as drug delivery and regenerative medicine, is critically dependent on understanding the hydrogel solution responses as a function of all three parameters together. In this work, interpenetrating polymer network (IPN) hydrogels of polyacrylamide and poly(acrylic acid) were formulated over a broad range of synthesis variables using a fractional factorial design, and were examined for equilibrium temperature responsive swelling in a variety of solution conditions. Due to the acidic nature of these IPN hydrogels, usable upper critical solution temperature (UCST) responses for this system occur in mildly acidic environments. Responses were characterized in terms of maximum equilibrium swelling and temperature-triggered swelling using turbidity and gravimetric measurements. Additionally, synthesis parameters critical to achieving optimal overall swelling, temperature-triggered swelling, and sigmoidal temperature transitions for this IPN system were analyzed based on the fractional factorial design used to formulate these hydrogels. PMID:26405349

  7. Swelling and dissolution of cellulose in amine oxide/water systems

    SciTech Connect

    Chanzy, H.; Noe, P.; Paillet, M.; Smith, P.

    1983-01-01

    The swelling behavior and the dissolution process of various cellulosic fibers, both native and regenerated, in N-methylmorpholine N-oxide (MMNO), dimethylethanolamine N-oxide (DMEAO), and mixtures thereof were studied in the presence of various amounts of water. The principal tools in this investigation were optical microscopy and wide-angle X-ray scattering (WAXS). The two amine oxides could either dissolve or only swell cellulose, depending on the water concentration, which was found to be of critical importance. Three domains of water concentration were found important. When only a few percent water was present, cellulose fibers, such as ramie, cotton, rayon, etc., dissolved readily without noticeable swelling in the amine oxide/water system brought above its melting point. At a relatively high water concentration (e.g., 18% w/w for MMNO), the cellulose fibers exhibited an extensive swelling (up to sevenfold increase in the fiber diameter) but no dissolution. In that case, the removal of the swelling agent showed that the initial native cellulose fibers were converted into an unoriented cellulose II structure. With still greater water content (e.g., 20% and more for MMNO or 15% for DMEAO), only partial swelling was observed, and the native cellulose fibers recovered their initial oriented cellulose I structure after removal of the swelling medium. X-ray investigations provided no evidence forthe formation of cellulose/solvent complexes in the swollen fibers. A relatively large decrease of the cellulose I (110) reflection was found in the WAXS patterns of the gels. This is interpreted as due to a preferential cleavage of the cellulose crystals along the corresponding plane when the cellulose fibers are exposed to the swelling forces of the amine oxide/water systems. 29 references, 13 figures, 1 table.

  8. Safety and Efficacy of Cerebrolysin in Infants with Communication Defects due to Severe Perinatal Brain Insult: A Randomized Controlled Clinical Trial

    PubMed Central

    Deifalla, Shaymaa M.; El-Houssinie, Moustafa; Mokbel, Somaia A.

    2016-01-01

    Background and Purpose The neuroregenerative drug Cerebrolysin has demonstrated efficacy in improving cognition in adults with stroke and Alzheimer's disease. The aim of this study was to determine the efficacy and safety of Cerebrolysin in the treatment of communication defects in infants with severe perinatal brain insult. Methods A randomized placebo-controlled clinical trial was conducted in which 158 infants (age 6-21 months) with communication defects due to severe perinatal brain insult were enrolled; 120 infants completed the study. The Cerebrolysin group (n=60) received twice-weekly Cerebrolysin injections of 0.1 mL/kg body weight for 5 weeks (total of ten injections). The placebo group (n=60) received the same amount and number of normal saline injections. Results The baseline Communication and Symbolic-Behavior-Scale-Developmental Profile scores were comparable between the two groups. After 3 months, the placebo group exhibited improvements in the social (p<0.01) and speech composite (p=0.02) scores, with 10% and 1.5% increases from baseline, respectively. The scores of the Cerebrolysin group changed from concern to no concern, with increases of 65.44%, 45.54%, 358.06%, and 96.00% from baseline in the social (p<0.001), speech (p<0.001), symbolic (p<0.001), and total (p<0.001) scores. Conclusions Cerebrolysin dramatically improved infants' communication especially symbolic behavior which positively affected social interaction. These findings suggest that cerebrolysin may be an effective and feasible way equivalent to stem cell therapy. PMID:26365023

  9. Morphological effect on swelling behaviour of hydrogel

    SciTech Connect

    Yacob, Norzita; Hashim, Kamaruddin

    2014-02-12

    Hydrogels are hydrophilic polymer networks that are capable of imbibing large amounts of water. In this work, hydrogels prepared from natural and synthetic polymers were irradiated by using electron beam irradiation. The morphology of hydrogel inter-polymeric network (IPN) was investigated using Scanning Electron Microscopy (SEM). The studies reveal correlations between pore sizes of IPN with degree of cross-linking. This relation also has an effect on swelling properties of the hydrogel. The results indicated that hydrogel with smaller pore size, as a result of much dense IPN, would decrease water uptake capacity. Combination of natural and synthetic polymers to form hydrogel affects the pore size and swelling property of the hydrogel as compared to each component of polymer.

  10. Morphological effect on swelling behaviour of hydrogel

    NASA Astrophysics Data System (ADS)

    Yacob, Norzita; Hashim, Kamaruddin

    2014-02-01

    Hydrogels are hydrophilic polymer networks that are capable of imbibing large amounts of water. In this work, hydrogels prepared from natural and synthetic polymers were irradiated by using electron beam irradiation. The morphology of hydrogel inter-polymeric network (IPN) was investigated using Scanning Electron Microscopy (SEM). The studies reveal correlations between pore sizes of IPN with degree of cross-linking. This relation also has an effect on swelling properties of the hydrogel. The results indicated that hydrogel with smaller pore size, as a result of much dense IPN, would decrease water uptake capacity. Combination of natural and synthetic polymers to form hydrogel affects the pore size and swelling property of the hydrogel as compared to each component of polymer.

  11. Molecular accessibility in solvent swelled coals

    SciTech Connect

    Kispert, L.D.

    1993-02-01

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a non swelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration is measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method had also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data show that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 mn). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of the EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of coal, thus providing information on the importance of molecular shape.

  12. Evolution of midplate hotspot swells: Numerical solutions

    NASA Technical Reports Server (NTRS)

    Liu, Mian; Chase, Clement G.

    1990-01-01

    The evolution of midplate hotspot swells on an oceanic plate moving over a hot, upwelling mantle plume is numerically simulated. The plume supplies a Gaussian-shaped thermal perturbation and thermally-induced dynamic support. The lithosphere is treated as a thermal boundary layer with a strongly temperature-dependent viscosity. The two fundamental mechanisms of transferring heat, conduction and convection, during the interaction of the lithosphere with the mantle plume are considered. The transient heat transfer equations, with boundary conditions varying in both time and space, are solved in cylindrical coordinates using the finite difference ADI (alternating direction implicit) method on a 100 x 100 grid. The topography, geoid anomaly, and heat flow anomaly of the Hawaiian swell and the Bermuda rise are used to constrain the models. Results confirm the conclusion of previous works that the Hawaiian swell can not be explained by conductive heating alone, even if extremely high thermal perturbation is allowed. On the other hand, the model of convective thinning predicts successfully the topography, geoid anomaly, and the heat flow anomaly around the Hawaiian islands, as well as the changes in the topography and anomalous heat flow along the Hawaiian volcanic chain.

  13. Controlling morphology in swelling-induced wrinkled surfaces

    NASA Astrophysics Data System (ADS)

    Breid, Derek Ronald

    ranging from 50--1000 μm were fabricated using the same material system. Upon wrinkling, the hemispheres formed complex hierarchical assemblies reminiscent of naturally occurring structures. The curvature of a surface exhibited a correlation with its critical buckling stress, independent of other factors. This enables the surface curvature to be used as an independent control over the dimple-to-ridge transition which occurs as a function of overstress. As in the flat buckling surfaces, this transition was shown to occur at an overstress value of ˜2. Surface curvature was also shown to improve the observed hexagonal ordering of the dimple arrays, resulting in the formation of regular "golf ball" structures. Geometric effects in finite flat plates were also examined. Using circular masks during the oxidation process, plates with radii ranging from 0.4--8.6 mm were created. Upon wrinkling, a dimple-to-ridge transition was observed with increasing plate size, with the morphological switch occurring at a radius of ˜2 mm. This observed transition was not found to be due to the inherent mechanics of plates of different sizes, but instead to a reduction in the oxide conversion due to shadowing or stagnation caused by the masking process, which lowered the applied overstress. The shape of the finite plate was found to have little impact on the resulting wrinkle morphologies. Kinetic aspects of wrinkling were qualitatively characterized by observing the wrinkling process over the course of swelling. Wrinkling was observed to frontally propagate across the surface, and the ordering of the patterns which developed showed a qualitative correlation with the degree of uniformity in the advancing wrinkle front. Swelling with different solvents was found to lead to the formation of different patterns, based on the swelling kinetics of the UVO-treated PDMS upon exposure to each solvent.

  14. Feet swelling in a multistage ultraendurance triathlete: a case study

    PubMed Central

    Knechtle, Beat; Zingg, Matthias Alexander; Knechtle, Patrizia; Rosemann, Thomas; Rüst, Christoph Alexander

    2015-01-01

    Recent studies investigating ultraendurance athletes showed an association between excessive fluid intake and swelling of the lower limbs such as the feet. To date, this association has been investigated in single-stage ultraendurance races, but not in multistage ultraendurance races. In this case study, we investigated a potential association between fluid intake and feet swelling in a multistage ultraendurance race such as a Deca Iron ultratriathlon with ten Ironman triathlons within 10 consecutive days. A 49-year-old well-experienced ultratriathlete competed in autumn 2013 in the Deca Iron ultratriathlon held in Lonata del Garda, Italy, and finished the race as winner within 129:33 hours:minutes. Changes in body mass (including body fat and lean body mass), foot volume, total body water, and laboratory measurements were assessed. Food and fluid intake during rest and competing were recorded, and energy and fluid turnovers were estimated. During the ten stages, the volume of the feet increased, percentage body fat decreased, creatinine and urea levels increased, hematocrit and hemoglobin values decreased, and plasma [Na+] remained unchanged. The increase in foot volume was significantly and positively related to fluid intake during the stages. The poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. This case report shows that the volume of the foot increased during the ten stages, and the increase in volume was significantly and positively related to fluid intake during the stages. Furthermore, the poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. The continuous feet swelling during the race was most probably due to a combination of a high fluid intake and a progressive decline in renal function (ie, continuous increase in creatinine and urea), leading to body fluid retention (ie, increase in total body water). PMID:26508884

  15. Feet swelling in a multistage ultraendurance triathlete: a case study.

    PubMed

    Knechtle, Beat; Zingg, Matthias Alexander; Knechtle, Patrizia; Rosemann, Thomas; Rüst, Christoph Alexander

    2015-01-01

    Recent studies investigating ultraendurance athletes showed an association between excessive fluid intake and swelling of the lower limbs such as the feet. To date, this association has been investigated in single-stage ultraendurance races, but not in multistage ultraendurance races. In this case study, we investigated a potential association between fluid intake and feet swelling in a multistage ultraendurance race such as a Deca Iron ultratriathlon with ten Ironman triathlons within 10 consecutive days. A 49-year-old well-experienced ultratriathlete competed in autumn 2013 in the Deca Iron ultratriathlon held in Lonata del Garda, Italy, and finished the race as winner within 129:33 hours:minutes. Changes in body mass (including body fat and lean body mass), foot volume, total body water, and laboratory measurements were assessed. Food and fluid intake during rest and competing were recorded, and energy and fluid turnovers were estimated. During the ten stages, the volume of the feet increased, percentage body fat decreased, creatinine and urea levels increased, hematocrit and hemoglobin values decreased, and plasma [Na(+)] remained unchanged. The increase in foot volume was significantly and positively related to fluid intake during the stages. The poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. This case report shows that the volume of the foot increased during the ten stages, and the increase in volume was significantly and positively related to fluid intake during the stages. Furthermore, the poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. The continuous feet swelling during the race was most probably due to a combination of a high fluid intake and a progressive decline in renal function (ie, continuous increase in creatinine and urea), leading to body fluid retention (ie, increase in total body water). PMID:26508884

  16. Apolipoprotein E3/E3 genotype decreases the risk of pituitary dysfunction after traumatic brain injury due to various causes: preliminary data.

    PubMed

    Tanriverdi, Fatih; Taheri, Serpil; Ulutabanca, Halil; Caglayan, Ahmet Okay; Ozkul, Yusuf; Dundar, Munis; Selcuklu, Ahmet; Unluhizarci, Kursad; Casanueva, Felipe F; Kelestimur, Fahrettin

    2008-09-01

    Traumatic brain injury (TBI) is a devastating public health problem which may result in hypopituitarism. However, the mechanisms and the risk factors responsible for hypothalamo-pituitary dysfunction due to TBI are still unclear. Although APO E is one of the most abundant protein in hypothalamo-pituitary region, there is no study investigating the relation between APO E polymorphism and TBI-induced hypopituitarism. This study was undertaken to determine whether APO E genotypes modulate the pituitary dysfunction risk after TBI due to various causes, including traffic accident, boxing, and kickboxing. Ninety-three patients with TBI (mean age, 30.61 +/- 1.25 years) and 27 healthy controls (mean age, 29.03 +/- 1.70 years) were included in the study. Pituitary functions were evaluated, and APO E genotypes (E2/E2; E3/E3; E4/E4; E2/E3; E2/E4; E3/E4) were screened. Twenty-four of 93 subjects (25.8%) had pituitary dysfunction after TBI. The ratio of pituitary dysfunction was significantly lower in subjects with APO E3/E3 (17.7%) than the subjects without APO E3/E3 genotype (41.9%; p = 0.01), and the corresponding odds ratio was 0.29 (95% confidence interval [CI], 0.11-0.78). In conclusion, this study provides strong evidence for the first time that APO E polymorphism is associated with the development of TBI-induced pituitary dysfunction. Present data demonstrated that APO E3/E3 genotype decreases the risk of hypopituitarism after TBI. The demonstration of the association between the APO E polymorphism and TBI may provide a new point of view in this field and promote further studies.

  17. Swelling/syneresis phenomena in gel-forming interpolymer complexes.

    PubMed

    Bell, C L; Peppas, N A

    1996-01-01

    Grafted poly(methacrylic acid-g-ethylene glycol) (P(MAA-g-EG)) copolymers were synthesized and their pH sensitivity investigated as a function of copolymer composition and PEG graft molecular weight. Interpolymer complexation occurred by hydrogen bonding between carboxylic groups on poly(methacrylic acid) (PMAA) and ether groups on poly(ethylene glycol) (PEG). This complexation was sensitive to the surrounding environment as complexes formed at pH levels low enough to insure substantial protonation of PMAA acid groups. At high pH, the acid groups became neutralized and did not form complexes. P(MAA-g-EG) membranes showed pH-sensitivity due to complex formation and dissociation. Uncomplexed equilibrium swelling ratios were much higher than those of the complexed states and varied according to copolymer composition and PEG graft length. Mesh sizes in the two states were determined. Swelling under oscillatory pH conditions and constant ionic strength revealed the dynamic sensitivity of P(MAA-g-EG) membranes. Under changing pH conditions, network syneresis (complexation) occurred more rapidly than network expansion (decomplexation) because of the rates of diffusion of specific ions causing the responses. No distinct water fronts were observed. Instead, water transport was continuous through the gel. These gels show great promise for a number of biomedical applications where fast biomaterial response is necessary.

  18. Segmentation of knee injury swelling on infrared images

    NASA Astrophysics Data System (ADS)

    Puentes, John; Langet, Hélène; Herry, Christophe; Frize, Monique

    2011-03-01

    Interpretation of medical infrared images is complex due to thermal noise, absence of texture, and small temperature differences in pathological zones. Acute inflammatory response is a characteristic symptom of some knee injuries like anterior cruciate ligament sprains, muscle or tendons strains, and meniscus tear. Whereas artificial coloring of the original grey level images may allow to visually assess the extent inflammation in the area, their automated segmentation remains a challenging problem. This paper presents a hybrid segmentation algorithm to evaluate the extent of inflammation after knee injury, in terms of temperature variations and surface shape. It is based on the intersection of rapid color segmentation and homogeneous region segmentation, to which a Laplacian of a Gaussian filter is applied. While rapid color segmentation enables to properly detect the observed core of swollen area, homogeneous region segmentation identifies possible inflammation zones, combining homogeneous grey level and hue area segmentation. The hybrid segmentation algorithm compares the potential inflammation regions partially detected by each method to identify overlapping areas. Noise filtering and edge segmentation are then applied to common zones in order to segment the swelling surfaces of the injury. Experimental results on images of a patient with anterior cruciate ligament sprain show the improved performance of the hybrid algorithm with respect to its separated components. The main contribution of this work is a meaningful automatic segmentation of abnormal skin temperature variations on infrared thermography images of knee injury swelling.

  19. Quantitative analyses of extrudate swell for polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Kejian; Sun, Chongxiao

    2009-07-01

    The quantitative theory of extrudate swell for nanocomposite and pure polymer is significant either for optimum processing or for understanding their viscoelasticity. Based on Song's die swell theory for entangled polymers, one extrudate swell correlation with material properties and capillary parameters was developed for polymer melt and their nanocomposites when compensating reservoir entry effect. It was the first to find that the composite swell ratio can be the matrix swell ratio multiplied by the concentration shift factor. The factor is the functions of the shear field, filler content, filler internal structure and the surface state as well as the matrix properties. The quantitative model was well fitful for the five kinds of nanoomposites.

  20. Mineralogy-swelling potential relationships for expansive shales

    USGS Publications Warehouse

    Olsen, H.W.; Krosley, L.; Nelson, K.; Chabrillat, S.; Goetz, A.F.H.; Noe, D.C.

    2000-01-01

    The extent to which mineralogy and swelling potential is correlated in the expansive clays and shales is studied. Sites are selected in Cretaceous shales, including Pierre Shale, that are uplifted into steeply dipping strata near the foothills of the Rocky Mountains. Swelling potentials are obtained on limited suites of samples with conventional and labor-intensive schemes including Seed and Chen's schemes, and with swell-consolidation measurements in response to saturation, consolidation, and rebound in an oedometer. The results showing the percent total smectite provide a useful index of swelling potential concept defined by Seed and correlates well with the swelling potential indices developed by Seed, Chen, and McKeen.

  1. Characteristics of the large-height swell-like waves on the east coast of Korea

    NASA Astrophysics Data System (ADS)

    Oh, S.-H.; Jeong, W.-M.; Baek, W.-D.

    2012-04-01

    On the east coast of Korean peninsula, unusually high swell-like waves are occasionally observed several times during the winter season. These high swell-like waves are not related to the northwest monsoon that is typical in winter season, but are generated when strong northeasters blow continuously over the East Sea of Korea. In recent years, exceptionally high swell-like waves compared to the past observation record has attacked the east coast of Korean peninsula and caused severe casualties and damages of ships and coastal structures. Taking a few examples, abnormally high swell-waves of Hs =9.69 m were observed near Sokcho harbor on October 2006. More recently on the first day of Year 2011, large-height swell-like waves of Hs = 6.7 m visited at Jukbyeon port. At the present, the occurrence of such high swell-like waves are not fully predicted and only partially included in the normal weather forecast. Hence, researchers have much interest in improving understanding of the detailed generation mechanism of the high swell-like waves and predicting its occurrence. In this presentation, the characteristics of the high swell-like waves occurred on the first day of 2011 will be reported, with some supplementary results of the other big wave events that occurred previously. The New Year wave was monitored at 12 measuring stations simultaneously along the east coast. By analyzing these wave data with the corresponding meteorological data provided by Korean Meteorological Agency (KMA), major characteristics of these waves were clarified in some detail. The reason for appearance of the high swell-like waves was found to be due to the long-lasting strong northeasters in the East Sea, which was formed as a result of the low pressure trough in the vicinity of the extra-tropical low pressure system that advances to East Sea from the China inland with decreasing its central pressure. Such a strong low pressure system can be occasionally developed in winter season and may cause

  2. Cellulose nanocrystal interactions probed by thin film swelling to predict dispersibility

    NASA Astrophysics Data System (ADS)

    Reid, Michael S.; Villalobos, Marco; Cranston, Emily D.

    2016-06-01

    The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of the interactions between components. Measuring the cohesive particle-particle interactions and the adhesive particle-polymer interactions is challenging due to nanoscale dimensions and poor colloidal stability of nanoparticles in many solvents. We demonstrate a new cohesive interaction measurement method using cellulose nanocrystals (CNCs) as a model system; CNCs have recently gained attention in the composites community due to their mechanical strength and renewable nature. Multi-wavelength surface plasmon resonance spectroscopy (SPR) was used to monitor the swelling of CNC thin films to elucidate the primary forces between CNCs. This was achieved by measuring swelling in situ in water, acetone, methanol, acetonitrile, isopropanol, and ethanol and relating the degree of swelling to solvent properties. Films swelled the most in water where we estimate 1.2-1.6 nm spacings between CNCs (or 4-6 molecular layers of water). Furthermore, a correlation was found between film swelling and the solvent's Hildebrand solubility parameter (R2 = 0.9068). The hydrogen bonding component of the solubility parameters was more closely linked to swelling than the polar or dispersive components. The films remained intact in all solvents, and using DLVO theory we have identified van der Waals forces as the main cohesive interaction between CNCs. The trends observed suggest that solvents (and polymers) alone are not sufficient to overcome CNC-CNC cohesion and that external energy is required to break CNC agglomerates. This work not only demonstrates that SPR can be used as a tool to measure cohesive particle-particle interactions but additionally advances our fundamental understanding of CNC interactions which is necessary for the design of cellulose nanocomposites.The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of

  3. Cellulose nanocrystal interactions probed by thin film swelling to predict dispersibility

    NASA Astrophysics Data System (ADS)

    Reid, Michael S.; Villalobos, Marco; Cranston, Emily D.

    2016-06-01

    The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of the interactions between components. Measuring the cohesive particle-particle interactions and the adhesive particle-polymer interactions is challenging due to nanoscale dimensions and poor colloidal stability of nanoparticles in many solvents. We demonstrate a new cohesive interaction measurement method using cellulose nanocrystals (CNCs) as a model system; CNCs have recently gained attention in the composites community due to their mechanical strength and renewable nature. Multi-wavelength surface plasmon resonance spectroscopy (SPR) was used to monitor the swelling of CNC thin films to elucidate the primary forces between CNCs. This was achieved by measuring swelling in situ in water, acetone, methanol, acetonitrile, isopropanol, and ethanol and relating the degree of swelling to solvent properties. Films swelled the most in water where we estimate 1.2-1.6 nm spacings between CNCs (or 4-6 molecular layers of water). Furthermore, a correlation was found between film swelling and the solvent's Hildebrand solubility parameter (R2 = 0.9068). The hydrogen bonding component of the solubility parameters was more closely linked to swelling than the polar or dispersive components. The films remained intact in all solvents, and using DLVO theory we have identified van der Waals forces as the main cohesive interaction between CNCs. The trends observed suggest that solvents (and polymers) alone are not sufficient to overcome CNC-CNC cohesion and that external energy is required to break CNC agglomerates. This work not only demonstrates that SPR can be used as a tool to measure cohesive particle-particle interactions but additionally advances our fundamental understanding of CNC interactions which is necessary for the design of cellulose nanocomposites.The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of

  4. Functional characteristics and molecular identification of swelling-activated chloride conductance in adult rabbit heart ventricles.

    PubMed

    Li, Jingdong; Wu, Xiangqiong; Cui, Tianpen

    2008-02-01

    Outwardly rectifying swelling-activated chloride conductance (ICl,Swell) in rabbit heart plays a critical role in cardioprotection following ischemic preconditioning (IP). But the functional characterization and molecular basis of this chloride conductance in rabbit heart ventricular myocytes is not clear. Candidate chloride channel clones (e.g. ClC-2, ClC-3, ClC-4 and ClC-5) were determined using RT-PCR and Western blot analysis. Whole cell ICl,Swell was recorded from isolated rabbit ventricular myocytes using patch clamp techniques during hypo-osmotic stress. The inhibitory effects of 4,4' isothiocyanato-2,2-disulfonic acid (DIDS), 5-nitro-2(3-phenylroylamino) benzoic acid (NPPB) and indanyloxyacetic acid 94 (IAA-94) on ICl,Swell were examined. The expected size of PCR products for ClC-2, ClC-3 and ClC-4 but not for ClC-5 was obtained. ClC-2 and ClC-3 expression was confirmed by automated fluorescent DNA sequencing. RT-PCR and Western blot showed that ClC-4 was expressed in abundance and ClC-2 was expressed at somewhat lower levels. The biological and pharmacological properties of I(Cl,Swell), including outward rectification, activation due to cell volume change, sensitivity to DIDS, IAA-94 and NPPB were identical to those known properties of ICl,Swell in exogenously expressed systems and other mammals hearts. It was concluded that ClC-3 or ClC-4 might be responsible for the outwardly rectifying part of ICl,Swell and may be the molecular targets of cardioprotection associated with ischemic preconditioning or hypo-osmotic shock. PMID:18278453

  5. Cellulose nanocrystal interactions probed by thin film swelling to predict dispersibility.

    PubMed

    Reid, Michael S; Villalobos, Marco; Cranston, Emily D

    2016-06-16

    The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of the interactions between components. Measuring the cohesive particle-particle interactions and the adhesive particle-polymer interactions is challenging due to nanoscale dimensions and poor colloidal stability of nanoparticles in many solvents. We demonstrate a new cohesive interaction measurement method using cellulose nanocrystals (CNCs) as a model system; CNCs have recently gained attention in the composites community due to their mechanical strength and renewable nature. Multi-wavelength surface plasmon resonance spectroscopy (SPR) was used to monitor the swelling of CNC thin films to elucidate the primary forces between CNCs. This was achieved by measuring swelling in situ in water, acetone, methanol, acetonitrile, isopropanol, and ethanol and relating the degree of swelling to solvent properties. Films swelled the most in water where we estimate 1.2-1.6 nm spacings between CNCs (or 4-6 molecular layers of water). Furthermore, a correlation was found between film swelling and the solvent's Hildebrand solubility parameter (R(2) = 0.9068). The hydrogen bonding component of the solubility parameters was more closely linked to swelling than the polar or dispersive components. The films remained intact in all solvents, and using DLVO theory we have identified van der Waals forces as the main cohesive interaction between CNCs. The trends observed suggest that solvents (and polymers) alone are not sufficient to overcome CNC-CNC cohesion and that external energy is required to break CNC agglomerates. This work not only demonstrates that SPR can be used as a tool to measure cohesive particle-particle interactions but additionally advances our fundamental understanding of CNC interactions which is necessary for the design of cellulose nanocomposites. PMID:27256628

  6. Mitochondrial free radical overproduction due to respiratory chain impairment in the brain of a mouse model of Rett syndrome: protective effect of CNF1.

    PubMed

    De Filippis, Bianca; Valenti, Daniela; de Bari, Lidia; De Rasmo, Domenico; Musto, Mattia; Fabbri, Alessia; Ricceri, Laura; Fiorentini, Carla; Laviola, Giovanni; Vacca, Rosa Anna

    2015-06-01

    Rett syndrome (RTT) is a pervasive neurodevelopmental disorder mainly caused by mutations in the X-linked MECP2 gene associated with severe intellectual disability, movement disorders, and autistic-like behaviors. Its pathogenesis remains mostly not understood and no effective therapy is available. High circulating levels of oxidative stress markers in patients and the occurrence of oxidative brain damage in MeCP2-deficient mouse models suggest the involvement of oxidative stress in RTT pathogenesis. However, the molecular mechanism and the origin of the oxidative stress have not been elucidated. Here we demonstrate that a redox imbalance arises from aberrant mitochondrial functionality in the brain of MeCP2-308 heterozygous female mice, a condition that more closely recapitulates that of RTT patients. The marked increase in the rate of hydrogen peroxide generation in the brain of RTT mice seems mainly produced by the dysfunctional complex II of the mitochondrial respiratory chain. In addition, both membrane potential generation and mitochondrial ATP synthesis are decreased in RTT mouse brains when succinate, the complex II respiratory substrate, is used as an energy source. Respiratory chain impairment is brain area specific, owing to a decrease in either cAMP-dependent phosphorylation or protein levels of specific complex subunits. Further, we investigated whether the treatment of RTT mice with the bacterial protein CNF1, previously reported to ameliorate the neurobehavioral phenotype and brain bioenergetic markers in an RTT mouse model, exerts specific effects on brain mitochondrial function and consequently on hydrogen peroxide production. In RTT brains treated with CNF1, we observed the reactivation of respiratory chain complexes, the rescue of mitochondrial functionality, and the prevention of brain hydrogen peroxide overproduction. These results provide definitive evidence of mitochondrial reactive oxygen species overproduction in RTT mouse brain and

  7. Chronic eyelid swelling as an initial manifestation of myeloma-associated amyloidosis.

    PubMed

    Chee, Elaine; Kim, Yoon-Duck; Lee, Jung Hye; Woo, Kyung In

    2013-01-01

    Orbital amyloidosis is uncommon and difficult to diagnose due to their variable clinical presentations. The authors report a case of a patient who presents with chronic eyelid swelling as an initial manifestation of myeloma-associated amyloidosis. This patient was also found to have retrobulbar infiltration with no visual impairment. The authors also describe the first documentation of the atypical necrotic appearance of amyloidosis in the involved eyelid tissues. Myeloma-associated amyloidosis can present as chronic, nonspecific periorbital swelling, hence a biopsy of the affected tissues is important in preventing a delay in the correct diagnosis.

  8. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-05-29

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a nonswelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method has also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data show that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 nm). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of the coal, thus providing information on the importance of molecular shape.

  9. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-08-01

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a nonswelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method has also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data shows that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 nm). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of the EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of the coal, thus providing information on the importance of molecular shape.

  10. Bimodal swelling responses in microgel thin films.

    PubMed

    Sorrell, Courtney D; Lyon, L Andrew

    2007-04-26

    A series of studies on microgel thin films is described, wherein quartz crystal microgravimetry (QCM), surface plasmon resonance (SPR), and atomic force microscopy (AFM) have been used to probe the properties of microstructured polymer thin films as a function of film architecture and solution pH. Thin films composed of pNIPAm-co-AAc microgels were constructed by using spin-coating layer-by-layer (scLbL) assembly with poly(allylamine hydrochloride) (PAH) as a polycationic "glue". Our findings suggest that the interaction between the negatively charged microgels and the positively charged PAH has a significant impact on the pH responsivity of the film. These effects are observable in both the optical and mechanical behaviors of the films. The most significant changes in behavior are observed when the motional resistance of a quartz oscillator is monitored via QCM experiments. Slight changes to the film architecture and alternating the pH of the environment significantly changes the QCM and SPR responses, suggesting a pH-dependent swelling that is dependent on both particle swelling and polyelectrolyte de-complexation. Together, these studies allow for a deeper understanding of the morphological changes that take place in environmentally responsive microgel-based thin films. PMID:17407344

  11. Polymers for use in controlled release systems: the effect of surfactants on their swelling properties.

    PubMed

    Vlachou, M; Hani, N; Efentakis, M; Tarantili, P A; Andreopoulos, A G

    2000-07-01

    The effect of an ampholytic surfactant on the swelling properties of polymeric materials was studied, using various swelling liquids. Tablets were prepared consisting of hydroxypropyl methylcellulose, poly(oxyethylene) and sodium alginate. Tego betain was the non-ionic surfactant used as an additive in a series of samples made of the above polymers. Those tablets were immersed in distilled water, phosphate buffer and 0.1 N HCl, and their weight uptake was recorded as a function of time, in order to assess the swelling process. Measurements of the contact angle of the above systems were also carried out for estimating their wetting properties. The results of this study showed a selectivity among polymers, surfactant and surrounding liquid. Clearly, an enhancement of the swelling capacity of hydroxypropyl methylcellulose tablets due to the surfactant was recorded. An unclear effect was observed in the case of poly(oxyethylene), whereas for sodium alginate, the dominant factor is its water solubility that controls swelling behaviour. PMID:10972160

  12. Void swelling and precipitation in a titanium-modified austenitic stainless steel under proton irradiation

    NASA Astrophysics Data System (ADS)

    Kimoto, T.; Shiraishi, H.

    1985-07-01

    The correlation between void swelling and precipitation behavior in a 10% cold worked Fe-16.2Ni-14.6Cr-2.37Mo-1.79Mn-0.53Si-0.24Ti-0.06C alloy was examined with 200 keV proton irradiation. Swelling peak temperature after the proton irradiation to 10 dpa was about 823 K, and void swelling decreased steeply with increase in irradiation temperature from 823 to 923 K. Void swelling increased rapidly from 1.9 to 12.1% with increase in irradiation dose from 20 to 45 dpa at 873 K. Fine intragranular TiC precipitates, which were formed during initial stage of irradiation, dissolved gradually with increase in irradiation dose from 10 to 45 dpa at 873 K, while the amount of precipitation of needle-shaped Fe 2P phase containing titanium increased with increasing dose. The reduction of sink strength of the TiC precipitates due to the dissolution during irradiation was thought to cause the increase of swelling rate with increase in irradiation dose from 20 to 45 dpa at 873 K.

  13. Hygroscopic swelling and shrinkage of latewood cell wall micropillars reveal ultrastructural anisotropy

    PubMed Central

    Rafsanjani, Ahmad; Stiefel, Michael; Jefimovs, Konstantins; Mokso, Rajmund; Derome, Dominique; Carmeliet, Jan

    2014-01-01

    We document the hygroscopic swelling and shrinkage of the central and the thickest secondary cell wall layer of wood (named S2) in response to changes in environmental humidity using synchrotron radiation-based phase contrast X-ray tomographic nanoscopy. The S2 layer is a natural fibre-reinforced nano-composite polymer and is strongly reactive to water. Using focused ion beam, micropillars with a cross section of few micrometres are fabricated from the S2 layer of the latewood cell walls of Norway spruce softwood. The thin neighbouring cell wall layers are removed to prevent hindering or restraining of moisture-induced deformation during swelling or shrinkage. The proposed experiment intended to get further insights into the microscopic origin of the anisotropic hygro-expansion of wood. It is found that the swelling/shrinkage strains are highly anisotropic in the transverse plane of the cell wall, larger in the normal than in the direction parallel to the cell wall's thickness. This ultrastructural anisotropy may be due to the concentric lamellation of the cellulose microfibrils as the role of the cellulose microfibril angle in the transverse swelling anisotropy is negligible. The volumetric swelling of the cell wall material is found to be substantially larger than the one of wood tissues within the growth ring and wood samples made of several growth rings. The hierarchical configuration in wood optimally increases its dimensional stability in response to a humid environment with higher scales of complexity. PMID:24671938

  14. Swelling and diffusion of PNIPA-based gels for localized chemotherapy and hyperthermia.

    PubMed

    Oni, Y; Soboyejo, W O

    2012-01-01

    This paper presents the results of an experimental study of the swelling and diffusion of poly(N-iso-propyl-acrylamide) PNIPA-based gels with the potential for applications in bio-micro-electro-mechanical systems (BioMEMS) for localized cancer treatment that involves both chemotherapy and hyperthermia. The swelling due to the uptake of water, rhodamine dye and the cancer drug, paclitaxel, are studied using weight gain experiments that are conducted over a range of temperatures in which hyperthermia can occur during drug delivery. The release of rhodamine dye and paclitaxel is also elucidated by considering their diffusion through the gels. The underlying mechanisms of diffusion and swelling are discussed over a temperature range in which synergistic cancer treatment can be effected by the combined use of hyperthermia and chemotherapy. PMID:23177767

  15. Effects of swell on transport and dispersion of oil plumes within the ocean mixed layer

    NASA Astrophysics Data System (ADS)

    Chen, Bicheng; Yang, Di; Meneveau, Charles; Chamecki, Marcelo

    2016-05-01

    The transport in the ocean mixed layer (OML) of oil plumes originated from deepwater blowouts is studied using large eddy simulations. In particular, we focus on the effects of swell on the modulation of turbulence in the OML and its impact on oil transport. Results show that when the misalignment between the wind and the swell propagation is small, Langmuir cells develop and significantly enhance the vertical dilution of the oil plume. Conversely, when the misalignment is large, vertical dilution is suppressed when compared to the no-swell case. Due to the strong directional shear of the mean flow within the OML, plume depth significantly impacts mean transport direction. The size of oil droplets in the plume also plays an important role in vertical dilution and mean transport direction.

  16. Experimental study of swelling of irradiated solid methane during annealing

    NASA Astrophysics Data System (ADS)

    Shabalin, E.; Fedorov, A.; Kulagin, E.; Kulikov, S.; Melikhov, V.; Shabalin, D.

    2008-12-01

    Solid methane is still widely in use at pulsed neutron sources due to its excellent neutronic performance (IPNS, KENS, Second Target Station at ISIS), notwithstanding poor radiation properties. One of the specific problems is radiolytic hydrogen gas pressure on the walls of a methane chamber during annealing of methane. In this paper results of an experimental study of this phenomenon under fast neutron irradiation with the help of a specially made low temperature irradiation rig at the IBR-2 pulsed reactor are presented. The peak pressure on the wall of the experimental capsule during heating of a sample irradiated at 23-35 K appears to have a maximum of 2.7 MPa at an absorbed dose 20 MGy and then falls down with higher doses. The pressure always reached its peak value at the temperature range 72-79 K. Generally, three phases of methane swelling during heating can be distinguished, each characterized by a proper rate and intensity.

  17. Hypoxia Modulates the Swelling-Activated Cl Current in Human Glioblastoma Cells: Role in Volume Regulation and Cell Survival.

    PubMed

    Sforna, Luigi; Cenciarini, Marta; Belia, Silvia; Michelucci, Antonio; Pessia, Mauro; Franciolini, Fabio; Catacuzzeno, Luigi

    2017-01-01

    The malignancy of glioblastoma multiforme (GBM), the most common human brain tumor, correlates with the presence of hypoxic areas, but the underlying mechanisms are unclear. GBM cells express abundant Cl channels whose activity supports cell volume and membrane potential changes, ultimately leading to cell proliferation, migration, and escaping death. In non-tumor tissues Cl channels are modulated by hypoxia, which prompted us to verify whether hypoxia would also modulate Cl channels in GBM cells. Our results show that in GBM cell lines, acute application of a hypoxic solution activates a Cl current displaying the biophysical and pharmacological features of the swelling-activated Cl current (ICl,swell ). We also found that acute hypoxia increased the cell volume by about 20%, and a 30% hypertonic solution partially inhibited the hypoxia-activated Cl current, suggesting that cell swelling and the activation of the Cl current are sequential events. Notably, the hypoxia-induced cell swelling was followed by a regulatory volume decrease (RVD) mediated mainly by ICl,swell . Since, a hypoxia-induced prolonged cell swelling is usually regarded as a death insult, we hypothesized that the hypoxia-activated Cl current could limit cell swelling and prevent necrotic death of GBM cells under hypoxic conditions. In accordance, we found that the ICl,swell inhibitor DCPIB hampered the RVD process, and more importantly it sensibly increased the hypoxia-induced necrotic death in these cells. Taken together, these results suggest that Cl channels are strongly involved in the survival of GBM cells in a hypoxic environment, and may thus represent a new therapeutic target for this malignant tumor. J. Cell. Physiol. 232: 91-100, 2017. © 2016 Wiley Periodicals, Inc.

  18. Neurological and behavioral abnormalities, ventricular dilatation, altered cellular functions, inflammation, and neuronal injury in brains of mice due to common, persistent, parasitic infection

    PubMed Central

    Hermes, Gretchen; Ajioka, James W; Kelly, Krystyna A; Mui, Ernest; Roberts, Fiona; Kasza, Kristen; Mayr, Thomas; Kirisits, Michael J; Wollmann, Robert; Ferguson, David JP; Roberts, Craig W; Hwang, Jong-Hee; Trendler, Toria; Kennan, Richard P; Suzuki, Yasuhiro; Reardon, Catherine; Hickey, William F; Chen, Lieping; McLeod, Rima

    2008-01-01

    Background Worldwide, approximately two billion people are chronically infected with Toxoplasma gondii with largely unknown consequences. Methods To better understand long-term effects and pathogenesis of this common, persistent brain infection, mice were infected at a time in human years equivalent to early to mid adulthood and studied 5–12 months later. Appearance, behavior, neurologic function and brain MRIs were studied. Additional analyses of pathogenesis included: correlation of brain weight and neurologic findings; histopathology focusing on brain regions; full genome microarrays; immunohistochemistry characterizing inflammatory cells; determination of presence of tachyzoites and bradyzoites; electron microscopy; and study of markers of inflammation in serum. Histopathology in genetically resistant mice and cytokine and NRAMP knockout mice, effects of inoculation of isolated parasites, and treatment with sulfadiazine or αPD1 ligand were studied. Results Twelve months after infection, a time equivalent to middle to early elderly ages, mice had behavioral and neurological deficits, and brain MRIs showed mild to moderate ventricular dilatation. Lower brain weight correlated with greater magnitude of neurologic abnormalities and inflammation. Full genome microarrays of brains reflected inflammation causing neuronal damage (Gfap), effects on host cell protein processing (ubiquitin ligase), synapse remodeling (Complement 1q), and also increased expression of PD-1L (a ligand that allows persistent LCMV brain infection) and CD 36 (a fatty acid translocase and oxidized LDL receptor that mediates innate immune response to beta amyloid which is associated with pro-inflammation in Alzheimer's disease). Immunostaining detected no inflammation around intra-neuronal cysts, practically no free tachyzoites, and only rare bradyzoites. Nonetheless, there were perivascular, leptomeningeal inflammatory cells, particularly contiguous to the aqueduct of Sylvius and hippocampus

  19. Improvement of the Dimensional Stability of Powder Injection Molded Compacts by Adding Swelling Inhibitor into the Debinding Solvent

    NASA Astrophysics Data System (ADS)

    Fan, Yang-Liang; Hwang, Kuen-Shyang; Su, Shao-Chin

    2008-02-01

    Defects are frequently found in powder injection molded (PIM) compacts during solvent debinding due to the swelling of the binders. This problem can be alleviated by adjusting the composition of the debinding solvent. In this study, 10 vol pct swelling inhibitors were added into heptane, and the in-situ amounts of swelling and sagging of the specimen in the solvent were recorded using a noncontacting laser dilatometer. The results show that the addition of ethanol, 2-propanol, 1-butanol, and 1-pentanol reduced the amounts of swelling by 31, 21, 17, and 11 pct, respectively. This was because the small molecule alcohols, which do not dissolve paraffin wax (PW) or stearic acid (SA) in the binder system, could diffuse easily into the specimen and increased the portion of the swelling inhibitor inside. The amount of the extracted PW and SA also decreased, but only by 8.3, 6.1, 4.3, and 2.4 pct, respectively. The solubility parameters of 1-bromopropane (n-PB) and ethyl acetate (EA) are between those of heptane and alcohols, and they also yielded a slight reduction in the amounts of swelling by 6 and 11 pct, respectively. These results suggest that to reduce defects caused by binder swelling during solvent debinding, alcohols with high solubility parameters can be added into heptane without sacrificing significantly on the debinding rate.

  20. Release of Water Soluble Drugs from Dynamically Swelling POLY(2-HYDROXYETHYL Methacrylate - CO - Methacrylic Acid) Hydrogels.

    NASA Astrophysics Data System (ADS)

    Kou, Jim Hwai-Cher

    In this study, ionizable copolymers of HEMA and methacrylic acid (MA) are investigated for their potential use in developing pH dependent oral delivery systems. Because of the MA units, these gels swell extensively at high pH. Since solute diffusion in the hydrophilic polymers depends highly on the water content of the matrix, it is anticipated that the release rate will be modulated by this pH induced swelling. From a practical point of view, the advantage of the present system is that one can minimize drug loss in the stomach and achieve a programmed release in intestine. This approach is expected to improve delivery of acid labile drugs or drugs that cause severe gastrointestinal side effects. This work mainly focuses on the basic understanding of the mechanism involved in drug release from the poly(HEMA -co- MA) gels, especially under dynamic swelling conditions. Equilibrium swelling is first characterized since water content is the major determinant of transport properties in these gels. Phenylpropanolamine (PPA) is chosen as the model drug for the release study and its diffusion characteristics in the gel matrix determined. The data obtained show that the PPA diffusivity follows the free volume theory of Yasuda, which explains the accelerating effect of swelling on drug release. A mathematical model based on a diffusion mechanism has been developed to describe PPA release from the swelling gels. Based on this model, several significant conclusions can be drawn. First, the release rate can be modulated by the aspect ratio of the cylindrical geometry, and this has a practical implication in dosage form design. Second, the release rate can be lowered quite considerably if the dimensional increase due to swelling is significant. Consequently, it is the balance between the drug diffusivity increase and the gel dimensional growth that determines the release rate from the swelling matrix. Third, quasi-steady release kinetics, which are characteristic of swelling

  1. Magnetic relaxation: Coal swelling, extraction, pore size

    SciTech Connect

    Doetschman, D.C.

    1992-11-06

    The goals for year I of the grant were to extract the Argonne Coals, to swell them, to reswell their residues, to seal the various samples for measurements, to perform analyses of the samples and to measure their NMR decays. Because of an unexpected characteristic of the extraction process, more detailed analyses of the samples are being done than originally anticipated. The mass spectrometric analyses have not been completed. Because routine NMR analyses needed to be done in greater detail than anticipated, the NMR decay measurements have also been delayed. In order to offset these delays, all of the EPR samples, which were to have been examined in year III, have been prepared and a substantial proportion of the pulsed EPR measurements have been made.

  2. A simple model for the swelling of polymer networks

    SciTech Connect

    Painter, P.C.; Shenoy, S.L. )

    1993-07-15

    The Flory--Rehner approach to the solvent swelling of polymer networks is modified so as to abandon the affine deformation assumption. Instead, it is assumed that swelling occurs by a process of disinterspersion of cross-link junctions, and relationships between chain expansion and segment concentration are established using the ideas of de Gennes. Using this approach, we also examine osmotic deswelling, aspects of phase equilibria, and the maximum observed in differential swelling measurements.

  3. Hygromorphic behaviour of cellular material: hysteretic swelling and shrinkage of wood probed by phase contrast X-ray tomography

    NASA Astrophysics Data System (ADS)

    Derome, Dominique; Rafsanjani, Ahmad; Patera, Alessandra; Guyer, Robert; Carmeliet, Jan

    2012-10-01

    Wood is a hygromorphic material, meaning it responds to changes in environmental humidity by changing its geometry. Its cellular biological structure swells during wetting and shrinks during drying. The origin of the moisture-induced deformation lies at the sub-cellular scale. The cell wall can be considered a composite material with stiff cellulose fibrils acting as reinforcement embedded in a hemicellulose/lignin matrix. The bulk of the cellulose fibrils, forming 50% of the cell wall, are oriented longitudinally, forming long-pitched helices. Both components of cell wall matrix are displaying swelling. Moisture sorption and, to a lesser degree, swelling/shrinkage are known to be hysteretic. We quantify the affine strains during the swelling and shrinkage using high resolution images obtained by phase contrast synchrotron X-ray tomography of wood samples of different porosities. The reversibility of the swelling/shrinkage is found for samples with controlled moisture sorption history. The deformation is more hysteretic for high than for low density samples. Swelling/shrinkage due to ad/desorption of water vapour displays also a non-affine component. The reversibility of the swelling/shrinkage indicates that the material has a structural capacity to show a persistent cellular geometry for a given moisture state and a structural composition that allows for moisture-induced transitional states. A collection of qualitative observations of small subsets of cells during swelling/shrinkage is further studied by simulating the observed behaviour. An anisotropic swelling coefficient of the cell wall is found to emerge and its origin is linked to the anisotropy of the cellulose fibrils arrangement in cell wall layers.

  4. Immune-mediated Loss of Transgene Expression From Virally Transduced Brain Cells Is Irreversible, Mediated by IFNγ, Perforin, and TNFα, and due to the Elimination of Transduced Cells

    PubMed Central

    Zirger, Jeffrey M; Puntel, Mariana; Bergeron, Josee; Wibowo, Mia; Moridzadeh, Rameen; Bondale, Niyati; Barcia, Carlos; Kroeger, Kurt M; Liu, Chunyan; Castro, Maria G; Lowenstein, Pedro R

    2012-01-01

    The adaptive immune response to viral vectors reduces vector-mediated transgene expression from the brain. It is unknown, however, whether this loss is caused by functional downregulation of transgene expression or death of transduced cells. Herein, we demonstrate that during the elimination of transgene expression, the brain becomes infiltrated with CD4+ and CD8+ T cells and that these T cells are necessary for transgene elimination. Further, the loss of transgene-expressing brain cells fails to occur in the absence of IFNγ, perforin, and TNFα receptor. Two methods to induce severe immune suppression in immunized animals also fail to restitute transgene expression, demonstrating the irreversibility of this process. The need for cytotoxic molecules and the irreversibility of the reduction in transgene expression suggested to us that elimination of transduced cells is responsible for the loss of transgene expression. A new experimental paradigm that discriminates between downregulation of transgene expression and the elimination of transduced cells demonstrates that transduced cells are lost from the brain upon the induction of a specific antiviral immune response. We conclude that the anti-adenoviral immune response reduces transgene expression in the brain through loss of transduced cells. PMID:22233583

  5. Processes and controls in swelling anhydritic clay rocks

    NASA Astrophysics Data System (ADS)

    Mutschler, Thomas; Blum, Philipp; Butscher, Christoph

    2015-04-01

    Referring to the swelling of anhydritic clay rocks in tunneling, Leopold Müller-Salzburg noted in the third volume on tunneling of his fundamental text book on rock engineering that "a truly coherent explanation of these phenomena is still owing" (Müller-Salzburg 1978, p. 306). This valuation is still true after more than three decades of research in the field of swelling anhydritic clay rocks. One of the reasons is our limited knowledge of the processes involved in the swelling of such rocks, and of the geological, mineralogical, hydraulic, chemical and mechanical controls of the swelling. In this contribution, a review of processes in swelling anhydritic clay rocks and of associated controls is presented. Also numerical models that aim at simulating the swelling processes and controls are included in this review, and some of the remaining open questions are pointed out. By focusing on process-oriented work in this review, the presentation intends to stimulate further research across disciplines in the field of swelling anhydritic clay rocks to finally get a step further in managing the swelling problem in geotechnical engineering projects. Keywords: swelling; anhydritic clay rocks; review

  6. Clay swelling — A challenge in the oilfield

    NASA Astrophysics Data System (ADS)

    Anderson, R. L.; Ratcliffe, I.; Greenwell, H. C.; Williams, P. A.; Cliffe, S.; Coveney, P. V.

    2010-02-01

    Water-based drilling fluids are increasingly being used for oil and gas exploration, and are generally considered to be more environmentally acceptable than oil-based or synthetic-based fluids. Unfortunately, their use facilitates clay hydration and swelling. Clay swelling, which occurs in exposed sedimentary rock formations, can have an adverse impact on drilling operations and may lead to significantly increased oil well construction costs. Minimizing clay swelling is therefore an important area attracting a large amount of interest from both academia and industry. To effectively reduce the extent of clay swelling the mechanism by which clay minerals swell needs to be understood so that efficient swelling inhibitors may be developed. Acceptable clay swelling inhibitors must not only significantly reduce clay hydration, but must also meet increasingly stringent environmental guidelines while remaining cost effective. The development of these inhibitors, which are generally based upon water soluble polymers, therefore represents a challenge to oilfield geochemistry. This review aims to provide a comprehensive understanding of the mechanism by which clay minerals swell and what steps have been taken in the development of effective and environmentally friendly clay swelling inhibitors.

  7. Tracking the attenuation and nonbreaking dissipation of swells using altimeters

    NASA Astrophysics Data System (ADS)

    Jiang, Haoyu; Stopa, Justin E.; Wang, He; Husson, Romain; Mouche, Alexis; Chapron, Bertrand; Chen, Ge

    2016-02-01

    A method for systematically tracking swells across oceanic basins is developed by taking advantage of high-quality data from space-borne altimeters and wave model output. The evolution of swells is observed over large distances based on 202 swell events with periods ranging from 12 to 18 s. An empirical attenuation rate of swell energy of about 4 × 10-7 m-1 is estimated using these observations, and the nonbreaking energy dissipation rates of swells far away from their generating areas are also estimated using a point source model. The resulting acceptance range of nonbreaking dissipation rates is -2.5 to 5.0 × 10-7 m-1, which corresponds to a dissipation e-folding scales of at least 2000 km for steep swells, to almost infinite for small-amplitude swells. These resulting rates are consistent with previous studies using in-situ and synthetic aperture radar (SAR) observations. The frequency dispersion and angular spreading effects during swell propagation are discussed by comparing the results with other studies, demonstrating that they are the two dominant processes for swell height attenuation, especially in the near field. The resulting dissipation rates from these observations can be used as a reference for ocean engineering and wave modeling, and for related studies such as air-sea and wind-wave-turbulence interactions.

  8. Time-development of sulphate hydration in anhydritic swelling rocks

    NASA Astrophysics Data System (ADS)

    Serafeimidis, Konstantinos

    2015-04-01

    Anhydritic claystones are among the most problematic rocks in tunnelling due to their distinctive swelling properties. They consist of a clay matrix with distributed anhydrite particles, veins and layers and have caused severe damage to numerous tunnels excavated in the Gypsum Keuper formation in North-Western Switzerland and South-Western Germany. The swelling of anhydritic claystones which is mainly attributed to the transformation of anhydrite into gypsum (a chemical process which leads to an increase in the solids of 61 percent), is a markedly time-dependent process. It may take several decades to complete in nature and is therefore important for the design particularly of the final tunnel lining. Anhydrite occurs either in the form of particles or of layers and veins of different thicknesses and spacings. The particles may have an approximately spherical or rather prismatic form, while their size lies within a wide range (from few micrometer to few centimeter). The shape and size of the anhydrite particles and layers are important for the specific surface of anhydrite and thus for the evolution of its hydration over time. In the present contribution we focus on the kinetics of the chemical reactions in sulphatic rocks, limiting ourselves to closed systems, i.e. without investigating the effects of seepage flow and diffusive transport, which may also be important. In order to achieve this, a consistent and comprehensive dissolution and precipitation model has been developed that accounts for arbitrary geometrical forms of anhydrite as well as for the sealing of anhydrite by a layer of gypsum. The investigations have shown that anhydrite dissolution represents the limiting mechanism if anhydrite occurs in the form of larger particles or thicker veins (> 1 millimeter) and there are sufficient nuclei for gypsum growth (e.g. precipitation takes place on of the surfaces of inert minerals). It has also been indicated that the time required for the whole amount of

  9. The influence of fabrication procedure on the void swelling of an oxide dispersion strengthened ferritic alloy in a HVEM

    NASA Astrophysics Data System (ADS)

    Snykers, M.; Biermans, F.; Cornelis, J.

    The influence of changes in the fabrication procedure of ferritic alloys with compositions Fe-13Cr-Ti-Mo-TiO 2 on the swelling behaviour are investigated. The fabrication procedures are: casting, powder metallurgy 3- milling in air and powder metallurgy 3- milling in argon. No difference is found for the results obtained for the materials fabricated by casting and by powder metallurgy 3- milling in air. Slightly different results are obtained for the material fabricated by powder metallurgy 3- milling in argon. This material contains argon in solution in the matrix, which causes a small shift of the peak swelling temperature and of the peak swelling helium concentration for tests carried out at 450°C. The overall swelling of this material is the lowest due to the small grain size and to the high density of inclusions.

  10. Methodology for determining void swelling at very high damage under ion irradiation

    NASA Astrophysics Data System (ADS)

    Getto, E.; Sun, K.; Taller, S.; Monterrosa, A. M.; Jiao, Z.; Was, G. S.

    2016-08-01

    At very high damage levels in ion irradiated samples, the decrease in effective density of the irradiated material due to void swelling can lead to errors in quantifying swelling. HT9 was pre-implanted with 10 appm He and subjected to a raster-scanned beam with a damage rate of ∼1 × 10-3 dpa/s at 460oC. Voids were characterized from 0 to 1300 nm. Fixed damage rate and fixed depth methods were developed to account for damage-dependent porosity increase and resulting dependence on depth. The fixed depth method was more appropriate as it limits undue effects from the injected interstitial while maintaining a usable void distribution. By keeping the depth fixed and accounting for the change in damage rate due to reduced density, the steady state swelling rate was 10% higher than calculation of swelling from raw data. This method is easily translatable to other materials, ion types and energies and limits the impact of the injected interstitial.

  11. Synoptic View of a Swell Field in the Pacific: from Spaceborne SAR Measurements to Seismic Noise on the Coast

    NASA Astrophysics Data System (ADS)

    Husson, R.; Collard, F.; Ardhuin, F.; Stutzmann, E.; Balanche, A.

    2010-12-01

    . Hereby, our approach confirms that the observed micro-seismic activity in the Pacific has a strong contribution from swell, probably due to the reflection to the coast. This result emphasizes the possibility to use the energy of the swell signal measured by the seismic noise to validate the energy dynamic of the synthetic swell field, taking advantage of numerous seismic stations. Additionally, the estimation of transfer functions from the seismic noise to the swell energy would be a unique opportunity to revisit world-wide swell energy of the last 60 years given the historical seismic data available.

  12. Ischemia-induced endothelial cell swelling and mitochondrial dysfunction are attenuated by cinnamtannin D1, green tea extract, and resveratrol in vitro.

    PubMed

    Panickar, Kiran S; Qin, Bolin; Anderson, Richard A

    2015-10-01

    Polyphenols possess antioxidant and anti-inflammatory properties. Oxidative stress (OS) and inflammation have been implicated in the pathogenesis of cytotoxic brain edema in cerebral ischemia. In addition, OS and pro-inflammatory cytokines also damage the endothelial cells and the neurovascular unit. Endothelial cell swelling may contribute to a leaky blood-brain barrier which may result in vasogenic edema in the continued presence of the existing cytotoxic edema. We investigated the protective effects of polyphenols on cytotoxic cell swelling in bEND3 endothelial cultures subjected to 5 hours oxygen-glucose deprivation (OGD). A polyphenol trimer from cinnamon (cinnamtannin D1), a polyphenol-rich extract from green tea, and resveratrol prevented the OGD-induced rise in mitochondrial free radicals, cell swelling, and the dissipation of the inner mitochondrial membrane potential. Monocyte chemoattractant protein (also called CCL2), a chemokine, but not tumor necrosis factor-α or interleukin-6, augmented the cell swelling. This effect of monochemoattractant protein 1-1 was attenuated by the polyphenols. Cyclosporin A, a blocker of the mitochondrial permeability transition pore, did not attenuate cell swelling but BAPTA-AM, an intracellular calcium chelator did, indicating a role of [Ca(2+)]i but not the mPT in cell swelling. These results indicate that the polyphenols reduce mitochondrial reactive oxygen species and subsequent cell swelling in endothelial cells following ischemic injury and thus may reduce brain edema and associated neural damage in ischemia. One possible mechanism by which the polyphenols may attenuate endothelial cell swelling is through the reduction in [Ca(2+)]i.

  13. Ischemia-induced endothelial cell swelling and mitochondrial dysfunction are attenuated by cinnamtannin D1, green tea extract, and resveratrol in vitro.

    PubMed

    Panickar, Kiran S; Qin, Bolin; Anderson, Richard A

    2015-10-01

    Polyphenols possess antioxidant and anti-inflammatory properties. Oxidative stress (OS) and inflammation have been implicated in the pathogenesis of cytotoxic brain edema in cerebral ischemia. In addition, OS and pro-inflammatory cytokines also damage the endothelial cells and the neurovascular unit. Endothelial cell swelling may contribute to a leaky blood-brain barrier which may result in vasogenic edema in the continued presence of the existing cytotoxic edema. We investigated the protective effects of polyphenols on cytotoxic cell swelling in bEND3 endothelial cultures subjected to 5 hours oxygen-glucose deprivation (OGD). A polyphenol trimer from cinnamon (cinnamtannin D1), a polyphenol-rich extract from green tea, and resveratrol prevented the OGD-induced rise in mitochondrial free radicals, cell swelling, and the dissipation of the inner mitochondrial membrane potential. Monocyte chemoattractant protein (also called CCL2), a chemokine, but not tumor necrosis factor-α or interleukin-6, augmented the cell swelling. This effect of monochemoattractant protein 1-1 was attenuated by the polyphenols. Cyclosporin A, a blocker of the mitochondrial permeability transition pore, did not attenuate cell swelling but BAPTA-AM, an intracellular calcium chelator did, indicating a role of [Ca(2+)]i but not the mPT in cell swelling. These results indicate that the polyphenols reduce mitochondrial reactive oxygen species and subsequent cell swelling in endothelial cells following ischemic injury and thus may reduce brain edema and associated neural damage in ischemia. One possible mechanism by which the polyphenols may attenuate endothelial cell swelling is through the reduction in [Ca(2+)]i. PMID:24773045

  14. New constraints on the Hawaiian swell origin using wavelet analysis of the geoid to topography ratio

    NASA Astrophysics Data System (ADS)

    Cadio, C.; Ballmer, M.; Panet, I.; Ribe, N.; Diament, M.

    2012-04-01

    Analyzing the formation of hotspot swells, including the shallowness around the Hawaiian Islands, is critical for understanding the origin of intraplate volcanism and the underlying geodynamical processes. Two main hypotheses for the origin of this swell are generally considered: thermal lithospheric thinning, and dynamical support by a convective ascending plume. A major goal of these models is to quantitatively explain the two important characteristics of the Hawaiian swell: its topography and the corresponding geoid anomaly. In simple models of isostatic compensation, the geoid-to-topography ratio (GTR) is linearly related to the depth of the compensating mass; therefore it is often considered as a fundamental parameter to assess swell support mechanisms. According to previous work, the observed GTR has been reported to range from 4 to 5 m/km. The corresponding apparent compensation depth is about 45 km, which is shallower than predicted by the dynamic support model. However, analysis of the data processing methods shows that the applied bandpass filters to retain only characteristic wavelengths of the swell topography and geoid, cannot completely remove the signal due to loading of the volcanic edifices and related lithospheric flexure. In order to resolve these issues, we apply a continuous wavelet transform, which allows us to retrieve lateral variations of the GTR at each spatial scale. A series of synthetic tests based on different geodynamic models clearly indicates that by efficiently filtering the unwanted contributions, our approach is able to estimate the proper GTR of the Hawaiian swell. A high GTR of 8 m/km is recovered on the current hotspot location. Therefore, for the first time, the recovered GTR agrees with realistic geodynamic models of the Hawaiian plume. Accordingly, the thermal rejuvenation model can be ruled out by our analysis. Instead, the swell as a whole is shown to be mainly supported dynamically by the uprising Hawaiian plume

  15. Analysis and prediction of ocean swell using instrumented buoys

    NASA Technical Reports Server (NTRS)

    Mettlach, Theodore; Wang, David; Wittmann, Paul

    1994-01-01

    During the period 20-23 September 1990, the remnants of Supertyphoon Flo moved into the central North Pacific Ocean with sustained wind speeds of 28 m/s. The strong wind and large fetch area associated with this storm generated long-period swell that propagated to the west coast of North America. National Data Buoy Center moored-buoy stations, located in a network that ranged from the Gulf of Alaska to the California Bight, provided wave spectral estimates of the swell from this storm. The greatest dominant wave periods measured were approximately 20-25 s, and significant wave heights measured ranged from 3 to 8 m. Wave spectra from an array of three nondirectional buoys are used to find the source of the long-period swell. Directional wave spectra from a heave-pitch-roll buoy are also used to make an independent estimate of the source of the swell. The ridge-line method, using time-frequency contour plots of wave spectral energy density, is used to determine the time of swell generation, which is used with the appropriate surface pressure analysis to infer the swell generation area. The diagnosed sources of the swell are also compared with nowcasts from the Global Spectral Ocean Wave Model of the Fleet Numerical Oceanography Center. A simple method of predicting the propagation of ocean swell, by applying a simple kinematic model of wave propagation to the estimated point and time source, is demonstrated.

  16. Nanoscale Electrodes for Flexible Electronics by Swelling Controlled Cracking.

    PubMed

    Zhao, Qiang; Wang, Wenjun; Shao, Jinyou; Li, Xiangming; Tian, Hongmiao; Liu, Lu; Mei, Xuesong; Ding, Yucheng; Lu, Bingheng

    2016-08-01

    Nanogap electrodes are realized using pre-patterned electrodes and a swelling controlled cracking method. Parallel fabrication of nanogap electrodes on flexible substrates can be achieved using this method. This swelling-controlled cracking method is promising for fabricating high-performance flexible electronics. UV photodetectors with ZnO nanoparticle-bridged nanogap electrodes exhibit high responsivity and external quantum efficiency.

  17. Nanoscale Electrodes for Flexible Electronics by Swelling Controlled Cracking.

    PubMed

    Zhao, Qiang; Wang, Wenjun; Shao, Jinyou; Li, Xiangming; Tian, Hongmiao; Liu, Lu; Mei, Xuesong; Ding, Yucheng; Lu, Bingheng

    2016-08-01

    Nanogap electrodes are realized using pre-patterned electrodes and a swelling controlled cracking method. Parallel fabrication of nanogap electrodes on flexible substrates can be achieved using this method. This swelling-controlled cracking method is promising for fabricating high-performance flexible electronics. UV photodetectors with ZnO nanoparticle-bridged nanogap electrodes exhibit high responsivity and external quantum efficiency. PMID:27197807

  18. Skeletogenesis in the swell shark Cephaloscyllium ventriosum.

    PubMed

    Eames, B Frank; Allen, Nancy; Young, Jonathan; Kaplan, Angelo; Helms, Jill A; Schneider, Richard A

    2007-05-01

    Extant chondrichthyans possess a predominantly cartilaginous skeleton, even though primitive chondrichthyans produced bone. To gain insights into this peculiar skeletal evolution, and in particular to evaluate the extent to which chondrichthyan skeletogenesis retains features of an osteogenic programme, we performed a histological, histochemical and immunohistochemical analysis of the entire embryonic skeleton during development of the swell shark Cephaloscyllium ventriosum. Specifically, we compared staining properties among various mineralizing tissues, including neural arches of the vertebrae, dermal tissues supporting oral denticles and Meckel's cartilage of the lower jaw. Patterns of mineralization were predicted by spatially restricted alkaline phosphatase activity earlier in development. Regarding evidence for an osteogenic programme in extant sharks, a mineralized tissue in the perichondrium of C. ventriosum neural arches, and to a lesser extent a tissue supporting the oral denticle, displayed numerous properties of bone. Although we uncovered many differences between tissues in Meckel's cartilage and neural arches of C. ventriosum, both elements impart distinct tissue characteristics to the perichondral region. Considering the evolution of osteogenic processes, shark skeletogenesis may illuminate the transition from perichondrium to periosteum, which is a major bone-forming tissue during the process of endochondral ossification. PMID:17451531

  19. Skeletogenesis in the swell shark Cephaloscyllium ventriosum

    PubMed Central

    Eames, B Frank; Allen, Nancy; Young, Jonathan; Kaplan, Angelo; Helms, Jill A; Schneider, Richard A

    2007-01-01

    Extant chondrichthyans possess a predominantly cartilaginous skeleton, even though primitive chondrichthyans produced bone. To gain insights into this peculiar skeletal evolution, and in particular to evaluate the extent to which chondrichthyan skeletogenesis retains features of an osteogenic programme, we performed a histological, histochemical and immunohistochemical analysis of the entire embryonic skeleton during development of the swell shark Cephaloscyllium ventriosum. Specifically, we compared staining properties among various mineralizing tissues, including neural arches of the vertebrae, dermal tissues supporting oral denticles and Meckel's cartilage of the lower jaw. Patterns of mineralization were predicted by spatially restricted alkaline phosphatase activity earlier in development. Regarding evidence for an osteogenic programme in extant sharks, a mineralized tissue in the perichondrium of C. ventriosum neural arches, and to a lesser extent a tissue supporting the oral denticle, displayed numerous properties of bone. Although we uncovered many differences between tissues in Meckel's cartilage and neural arches of C. ventriosum, both elements impart distinct tissue characteristics to the perichondral region. Considering the evolution of osteogenic processes, shark skeletogenesis may illuminate the transition from perichondrium to periosteum, which is a major bone-forming tissue during the process of endochondral ossification. PMID:17451531

  20. Skeletogenesis in the swell shark Cephaloscyllium ventriosum.

    PubMed

    Eames, B Frank; Allen, Nancy; Young, Jonathan; Kaplan, Angelo; Helms, Jill A; Schneider, Richard A

    2007-05-01

    Extant chondrichthyans possess a predominantly cartilaginous skeleton, even though primitive chondrichthyans produced bone. To gain insights into this peculiar skeletal evolution, and in particular to evaluate the extent to which chondrichthyan skeletogenesis retains features of an osteogenic programme, we performed a histological, histochemical and immunohistochemical analysis of the entire embryonic skeleton during development of the swell shark Cephaloscyllium ventriosum. Specifically, we compared staining properties among various mineralizing tissues, including neural arches of the vertebrae, dermal tissues supporting oral denticles and Meckel's cartilage of the lower jaw. Patterns of mineralization were predicted by spatially restricted alkaline phosphatase activity earlier in development. Regarding evidence for an osteogenic programme in extant sharks, a mineralized tissue in the perichondrium of C. ventriosum neural arches, and to a lesser extent a tissue supporting the oral denticle, displayed numerous properties of bone. Although we uncovered many differences between tissues in Meckel's cartilage and neural arches of C. ventriosum, both elements impart distinct tissue characteristics to the perichondral region. Considering the evolution of osteogenic processes, shark skeletogenesis may illuminate the transition from perichondrium to periosteum, which is a major bone-forming tissue during the process of endochondral ossification.

  1. Opening of the blood-brain barrier tight junction due to shock wave induced bubble collapse: a molecular dynamics simulation study.

    PubMed

    Goliaei, Ardeshir; Adhikari, Upendra; Berkowitz, Max L

    2015-08-19

    Passage of a shock wave across living organisms may produce bubbles in the blood vessels and capillaries. It was suggested that collapse of these bubbles imposed by an impinging shock wave can be responsible for the damage or even destruction of the blood-brain barrier. To check this possibility, we performed molecular dynamics computer simulations on systems that contained a model of tight junction from the blood-brain barrier. In our model, we represent the tight junction by two pairs of interacting proteins, claudin-15. Some of the simulations were done in the absence of a nanobubble, some in its presence. Our simulations show that when no bubble is present in the system, no damage to tight junction is observed when the shock wave propagates across it. In the presence of a nanobubble, even when the impulse of the shock wave is relatively low, the implosion of the bubble causes serious damage to our model tight junction.

  2. Hyaluronan deficiency due to Has3 knock-out causes altered neuronal activity and seizures via reduction in brain extracellular space.

    PubMed

    Arranz, Amaia M; Perkins, Katherine L; Irie, Fumitoshi; Lewis, David P; Hrabe, Jan; Xiao, Fanrong; Itano, Naoki; Kimata, Koji; Hrabetova, Sabina; Yamaguchi, Yu

    2014-04-30

    Hyaluronan (HA), a large anionic polysaccharide (glycosaminoglycan), is a major constituent of the extracellular matrix of the adult brain. To address its function, we examined the neurophysiology of knock-out mice deficient in hyaluronan synthase (Has) genes. Here we report that these Has mutant mice are prone to epileptic seizures, and that in Has3(-/-) mice, this phenotype is likely derived from a reduction in the size of the brain extracellular space (ECS). Among the three Has knock-out models, namely Has3(-/-), Has1(-/-), and Has2(CKO), the seizures were most prevalent in Has3(-/-) mice, which also showed the greatest HA reduction in the hippocampus. Electrophysiology in Has3(-/-) brain slices demonstrated spontaneous epileptiform activity in CA1 pyramidal neurons, while histological analysis revealed an increase in cell packing in the CA1 stratum pyramidale. Imaging of the diffusion of a fluorescent marker revealed that the transit of molecules through the ECS of this layer was reduced. Quantitative analysis of ECS by the real-time iontophoretic method demonstrated that ECS volume was selectively reduced in the stratum pyramidale by ∼ 40% in Has3(-/-) mice. Finally, osmotic manipulation experiments in brain slices from Has3(-/-) and wild-type mice provided evidence for a causal link between ECS volume and epileptiform activity. Our results provide the first direct evidence for the physiological role of HA in the regulation of ECS volume, and suggest that HA-based preservation of ECS volume may offer a novel avenue for development of antiepileptogenic treatments.

  3. Water uptake and swelling hysteresis in a nafion thin film measured with neutron reflectometry.

    PubMed

    Kalisvaart, W Peter; Fritzsche, Helmut; Mérida, Walter

    2015-05-19

    Water uptake and swelling in a thin (∼15 nm) Nafion film on SiO2 native oxide on a Si wafer is studied as a function of relative humidity (8-97%) at room temperature and as a function of temperature (25-60 °C) at 97% relative humidity by neutron reflectometry. This is the first report on the behavior of thin Nafion films at elevated temperatures and high humidity. Large hysteresis is observed during the temperature cycle. The observed swelling strain in the film at 60 °C is 48% as compared to the as-deposited state, which is far above any previously observed trend at room temperature. A small decrease in the average SLD suggests that part of the additional swelling is due to thermal expansion, but the estimated D2O/SO3 ratio also increases by 70%. Half of the "excess" absorption and 73% of the additional swelling are retained during cooling back to room temperature. The results provide new insights into the dynamics of Nafion on nanometer scales under fuel cell operating conditions. PMID:25901752

  4. Influence of ethanol on swelling and release behaviors of Carbopol(®)-based tablets.

    PubMed

    Rahim, Safwan Abdel; Al-Ghazawi, Mutasim; Al-Zoubi, Nizar

    2013-01-01

    The aim of this work was to investigate the effect of ethanol on the in vitro swelling and release behaviors of Carbopol(®)-based tablets. The swelling behavior of drug-free compacts and the release of model drugs (metformin HCl, caffeine and theophylline) from matrix tablets were evaluated in acidic and buffered media with 0, 20 and 40% (v/v) ethanol. Release data were analyzed by fitting to Higuchi and Peppas models and calculation of similarity factor (f2). ANOVA tests were performed to determine significant factors on swelling and release. It was found that ethanol affects swelling and erosion of drug-free Carbopol(®) compacts, and the effect was highly dependent on medium pH. For matrix tablets, no dose dumping due to ethanol was manifested. The release rate and mechanism, however, were significantly affected by ethanol concentration as indicated by ANOVA applied to the constant, KH, from Higuchi model and the exponent, n, from Peppas model, respectively. The effect of ethanol on release was further confirmed by similarity factor results, which indicated that ethanol led to different release profiles (f2 < 50) in seven of eight cases for matrices containing metformin HCl and in three of eight cases for matrices containing caffeine and theophylline.

  5. Decongestion effect and rebound swelling of the nasal mucosa during 4-week use of oxymetazoline.

    PubMed

    Graf, P; Juto, J E

    1994-01-01

    The aim of this study was to investigate whether long-term use of oxymetazoline induces a rebound swelling of the nasal mucosa and whether the decongestion effect is altered during medication. Eight healthy volunteers had oxymetazoline nasal spray (0.5 mg/ml; 0.1 ml in each nostril, three times daily) for 30 days and registrations of the mucosal surface positions were made using rhinostereometry. Compared to the registrations before the start of medication, no rebound swelling was registered after 10 days. After 30 days, however, a rebound swelling was registered in all subjects (p < 0.001). All of them, then, also reported nasal stuffiness. The decongested position of the nasal mucosa after one single dose of oxymetazoline was the same in the whole study. It is concluded that rhinitis medicamentosa develops after a relatively short time on oxymetazoline, even in healthy volunteers, and that the swelling probably is due to a vasodilatation rather than an edema. The study supports the recommendation that the drug should not be used over periods > 10 days.

  6. Propionate induces cell swelling and K+ accumulation in shark rectal gland

    SciTech Connect

    Feldman, G.M.; Ziyadeh, F.N.; Mills, J.W.; Booz, G.W.; Kleinzeller, A. )

    1989-08-01

    Small organic anions have been reported to induce cell solute accumulation and swelling. To investigate the mechanism of swelling, we utilized preparations of rectal gland cells from Squalus acanthias incubated in medium containing propionate. Propionate causes cells to swell by diffusing across membranes in its nonionic form, acidifying cell contents, and activating the Na+-H+ antiporter. The Na+-H+ exchange process tends to correct intracellular pH (pHi), and thus it maintains a favorable gradient for propionic acid diffusion and allows propionate to accumulate. Activation of the Na+-H+ antiport also facilitates Na+ entry into the cell and Nai accumulation. At the same time Na+-K+-ATPase activity, unaffected by propionate, replaces Nai with Ki, whereas the K+ leak rate, decreased by propionate, allows Ki to accumulate. As judged by {sup 86}Rb+ efflux, the reduction in K+ leak was not due to propionate-induced cell acidification or reduction in Cli concentration. Despite inducing cell swelling, propionate did not disrupt cell structural elements and F actin distribution along cell membranes.

  7. Structure Within Thin Epoxy Films Revealed by Solvent Swelling: A Neutron Reflectivity Study

    SciTech Connect

    Yim, H.; Kent, M.; McNamara, W.F.; Ivkov, R.; Satija, S.; Majewski, J.

    1999-08-03

    Structure within thin epoxy films is investigated by neutron reflectivity (NR) as a function of resin/crosslinker composition and cure temperature. Variation in the crosslink density normal to the substrate surface is examined by swelling the films with the good solvent d-nitrobenzene (d-NB). The principle observation is a large excess of d-NB near the air surface. This is not a wetting layer,but rather indicates a lower crosslink density in the new-surface region. This effect is due to preferential segregation of the crosslinker to the air surface, driven by the lower surface energy of the crosslinker relative to the epoxide oligamers. The magnitude of the effect is a function of composition and cure temperature. Exclusion of d-N13from the region immediately adjacent to the substrate surface is also observed, possibly indicating a tightly bound layer of epoxy. Regarding swelling in the bulk of the films, the behavior is non-symmetric with departure from the stoichiometric ratio. The films deficient in curing agent show greater equilibrium swelling and faster swelling kinetics than the films with an excess of curing agent.

  8. Structure Within Thin Epoxy Films Revealed by Solvent Swelling: A Neutron Reflectivity Study

    NASA Astrophysics Data System (ADS)

    Yim, Hyun; Kent, Michael; Frere McNamara, W.; Ivkov, Robert; Satija, Sushil; Majewski, Jaroslaw

    2000-03-01

    Structure within thin epoxy films is investigated by neutron reflectivity (NR) as a function of resin/crosslinker composition and cure temperature. Variation in the crosslink density normal to the substrate surface is examined by swelling the films with the good solvent d-nitrobenzene (d-NB). The principal observation is a large excess of d-NB near the air surface. This is not a wetting layer, but rather indicates a lower crosslink density in the near-surface region. This effect is due to preferential segregation of the crosslinker to the air surface, driven by the lower surface tension of the crosslinker relative to the epoxide oligamers. The magnitude of the effect is a function of composition and cure temperature. Exclusion of d-NB from the region immediately adjacent to the substrate surface is also observed, possibly indicating a tightly bound layer of epoxy. Regarding swelling in the bulk of the films, the behavior is nonsymmetric with departure from the stoichiometric ratio. The films deficient in curing agent show greater equilibrium swelling and faster swelling kinetics than the films with an excess of curing agent.

  9. Optical measurement and modelling of parison sag and swell in blow moulding

    NASA Astrophysics Data System (ADS)

    Béreaux, Yves; Charmeau, Jean-Yves; Balcaen, Jean

    2011-05-01

    Blow moulding is a process whereby a cylindrical parison is extruded first, then pinched between the two halves of a mould and, finally, blown into the product. Parison size and shape result from complex interactions between mandrel and die geometries, processing parameters and viscoelastic properties of the polymeric material. Moreover, parison size changes with time due to sag. An innovative, contactless and online measurement technique of the parison is shown to be an effective tool to measure precisely parison diameter and thickness and to capture dimensional changes with time. This technique employs laser lighting of the parison and hinges on the refractive properties of molten polymer. Images taken with a digital camera are processed to give a precise measurement of diameter and thickness, at different time step during extrusion. Thus, parison swell and sag have been recorded for a commercial HDPE. Influence of processing parameters such as the rotational screw speed or die gap width can be brought forward. Thickness swell is found to possess a different behaviour from diameter swell. Swell is a purely viscoelastic phenomenon, therefore requiring a numerical modelling with an integral viscoelastic constitutive equation. On the other hand, sag has been measured and could be modelled from a Newtonian perspective using one dimensional convected coordinates. A sagging susceptibility coefficient of the polymer is deduced.

  10. Effect of groundwater chemistry on the swelling behavior of a Ca-bentonite for deep geological repository

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Chuan; Huang, Wei-Hsing

    The swelling properties of buffer material for high level radioactive waste repository in a near-field environment are of particular importance for achieving the low permeability sealing function. In this study, the free swelling behavior of a potential buffer material Zhisin clay is evaluated under simulated groundwater conditions such as immersion in NaCl, CaCl2, and Na2SO4 solutions at various concentrations. Experimental results indicate that Zhisin clay, being a Ca-bentonite, exhibits reduced swelling strain in salt solutions. The amount of decrease in swelling strain upon saline water intrusion is affected by both the type and concentration of electrolyte. At the same concentration, the swelling strains in CaCl2 solution are lower than those in NaCl solution due to the quasi-crystals formed in the presence of calcium ions. Also, the swells in Na2SO4 solution are found to be lower than those in NaCl solution. This is attributed to the precipitation of CaSO4, which acts as binding agent and results in aggregation of clay particles.

  11. French Polynesia Hotspot Swells Explained By Dynamic Topography

    NASA Astrophysics Data System (ADS)

    Adam, C.; Yoshida, M.; Isse, T.; Suetsugu, D.; Shiobara, H.; Sugioka, H.; Kanazawa, T.; Fukao, Y.; Barruol, G.

    2007-12-01

    Situated on the South Pacific Superswell, French Polynesia is a region characterized by numerous geophysical anomalies among which a high volcanism concentration. Seven hotspots are required to explain the observed chains, volcanism ages and geochemical trends. Many open questions still remain on the origin of these hotspot chains: are they created by passive uplift of magma due to discontinuities in the structure of the lithosphere or by the ascent of mantle plumes? In this case, at which depth do these plumes initiate in the mantle? Many geophysical observations (bathymetry, gravity, magnetism, volcanism ages..) are used to understand the unique phenomenon occurring on this region. The most useful information may come from tomography models since they provide a 3D view of the mantle. Until recently, the tomography models over the region were quite inaccurate because of the sparse location of the seismic stations. The deployment of two new seismic stations networks (BBOBS and temporary island stations) has lately remedied this failing. The resulting tomography model obtained through the inversion of Rayleigh waves provides the most accurate view of the shallowest part of the mantle (depths ≤ 240 km) beneath French Polynesia. Indeed, for the first time the accuracy of a tomography model is good enough to provide information about plume phenomenology in this complex region. In order to quantify the plumes effect on the seafloor, we compute the dynamic topography through an instantaneous flow model. The general trend of the observed depths anomalies (highs and lows) is well recovered. For example the amplitude, location and extension of the swells associated with the Society, Macdonald and Rarotonga are accurately described by the dynamic model. We also find that dynamic uplift is associated with the Tuamotu archipelago which means that a part of the observed swell is due to the present day action of plumes. Since no volcanism ages are available over this chain

  12. Swelling kinetics of poly(N-isopropylacrylamide) gel.

    PubMed

    Andersson, M; Axelsson, A; Zacchi, G

    1998-01-01

    In many gel applications the swelling and shrinking kinetics are very important, e.g. in controlled/slow release, where the kinetics determined the rate of out-diffusion of the active component, and in gel extraction where the gel is swollen and shrunk several times. In this study swelling kinetics of poly(N-isopropylacrylamide) gel (NiPAAm gel) was determined by monitoring the swelling process using a stereo microscope and a video camera. The swelling of spherical gel bodies could conveniently be studied after a temperature change. The results obtained were treated according to the approach of Tanaka and Fillmore, in which the swelling and shrinking of a gel is described as a motion of the gel network according to the diffusion equation. This was shown to be valid when the temperature changes are kept below the critical point of the gel. However, the model fails to describe the shrinking process when passing from below to above the critical temperature. The collective diffusion coefficient (D), defined as the osmotic bulk modulus divided by the friction factor, was determined by fitting to the experimental data. D was found to increase with temperature according to the Wilke-Chang relation D = 2.0.10(-11) + 7.6.10(-17).T/mu. The results were used to simulate the swelling/shrinking process. The simulations show the importance of having sufficiently small gel bodies to achieve a short swelling time.

  13. Alteration of default mode network in high school football athletes due to repetitive subconcussive mild traumatic brain injury: a resting-state functional magnetic resonance imaging study.

    PubMed

    Abbas, Kausar; Shenk, Trey E; Poole, Victoria N; Breedlove, Evan L; Leverenz, Larry J; Nauman, Eric A; Talavage, Thomas M; Robinson, Meghan E

    2015-03-01

    Long-term neurological damage as a result of head trauma while playing sports is a major concern for football athletes today. Repetitive concussions have been linked to many neurological disorders. Recently, it has been reported that repetitive subconcussive events can be a significant source of accrued damage. Since football athletes can experience hundreds of subconcussive hits during a single season, it is of utmost importance to understand their effect on brain health in the short and long term. In this study, resting-state functional magnetic resonance imaging (rs-fMRI) was used to study changes in the default mode network (DMN) after repetitive subconcussive mild traumatic brain injury. Twenty-two high school American football athletes, clinically asymptomatic, were scanned using the rs-fMRI for a single season. Baseline scans were acquired before the start of the season, and follow-up scans were obtained during and after the season to track the potential changes in the DMN as a result of experienced trauma. Ten noncollision-sport athletes were scanned over two sessions as controls. Overall, football athletes had significantly different functional connectivity measures than controls for most of the year. The presence of this deviation of football athletes from their healthy peers even before the start of the season suggests a neurological change that has accumulated over the years of playing the sport. Football athletes also demonstrate short-term changes relative to their own baseline at the start of the season. Football athletes exhibited hyperconnectivity in the DMN compared to controls for most of the sessions, which indicates that, despite the absence of symptoms typically associated with concussion, the repetitive trauma accrued produced long-term brain changes compared to their healthy peers.

  14. Seasonality of Ankle Swelling: Population Symptom Reporting Using Google Trends.

    PubMed

    Liu, Fangwei; Allan, G Michael; Korownyk, Christina; Kolber, Michael; Flook, Nigel; Sternberg, Harvey; Garrison, Scott

    2016-07-01

    In our experience, complaints of ankle swelling are more common in summer, typically from patients with no obvious cardiovascular disease. Surprisingly, this observation has never been reported. To objectively establish this phenomenon, we sought evidence of seasonality in the public's Internet searches for ankle swelling. Our data, obtained from Google Trends, consisted of all related Google searches in the United States from January 4, 2004, to January 26, 2016. Consistent with our expectations and confirmed by similar data for Australia, Internet searches for information on ankle swelling are highly seasonal (highest in midsummer), with seasonality explaining 86% of search volume variability.

  15. Molecular accessibility in solvent swelled coal. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1992-11-01

    To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were later confirmed by magnetic resonance imaging at Argonne National Lab and the University of Illinois.

  16. Seasonality of Ankle Swelling: Population Symptom Reporting Using Google Trends.

    PubMed

    Liu, Fangwei; Allan, G Michael; Korownyk, Christina; Kolber, Michael; Flook, Nigel; Sternberg, Harvey; Garrison, Scott

    2016-07-01

    In our experience, complaints of ankle swelling are more common in summer, typically from patients with no obvious cardiovascular disease. Surprisingly, this observation has never been reported. To objectively establish this phenomenon, we sought evidence of seasonality in the public's Internet searches for ankle swelling. Our data, obtained from Google Trends, consisted of all related Google searches in the United States from January 4, 2004, to January 26, 2016. Consistent with our expectations and confirmed by similar data for Australia, Internet searches for information on ankle swelling are highly seasonal (highest in midsummer), with seasonality explaining 86% of search volume variability. PMID:27401424

  17. Swelling and Contraction of Phaseolus Hypocotyl Mitochondria 1

    PubMed Central

    Earnshaw, M. J.; Truelove, B.

    1968-01-01

    Isolated Phaseolus mitochondria will swell spontaneously in buffered KCl and contract with an oxidizable substrate or ATP + Mg2+. The conditions under which the mitochondria are swollen affect subsequent contraction, substrate oxidation and ion accumulation, but not their oxidative phosphorylation ability. Bovine serum albumin reduces the rate of swelling and promotes substrate oxidation, contraction and ion accumulation. Swelling of these mitochondria is associated with the release of malic dehydrogenase and a loss of membrane integrity. The beneficial effects of bovine serum albumin in preserving the energy linked functions of Phaseolus mitochondria is discussed. PMID:16656729

  18. Modeling injected interstitial effects on void swelling in self-ion irradiation experiments

    NASA Astrophysics Data System (ADS)

    Short, M. P.; Gaston, D. R.; Jin, M.; Shao, L.; Garner, F. A.

    2016-04-01

    Heavy ion irradiations at high dose rates are often used to simulate slow and expensive neutron irradiation experiments. However, many differences in the resultant modes of damage arise due to unique aspects of heavy ion irradiation. One such difference was recently shown in pure iron to manifest itself as a double peak in void swelling, with both peaks located away from the region of highest displacement damage. In other cases involving a variety of ferritic alloys there is often only a single peak in swelling vs. depth that is located very near the ion-incident surface. We show that these behaviors arise due to a combination of two separate effects: 1) suppression of void swelling due to injected interstitials, and 2) preferential sinking of interstitials to the ion-incident surface, which are very sensitive to the irradiation temperature and displacement rate. Care should therefore be used in collection and interpretation of data from the depth range outside the Bragg peak of ion irradiation experiments, as it is shown to be more complex than previously envisioned.

  19. Development of an Operational Typhoon Swell Forecasting and Coastal Flooding Early Warning System

    NASA Astrophysics Data System (ADS)

    Fan, Y. M.; Wu, L. C.; Doong, D. J.; Kao, C. C.; Wang, J. H.

    2012-04-01

    Coastal floods and typhoon swells are a consistent threat to oceanfront countries, causing major human suffering and substantial economic losses, such as wrecks, ship capsized, and marine construction failure, etc. Climate change is exacerbating the problem. An early warning system is essential to mitigate the loss of life and property from coastal flooding and typhoon swells. The purpose of this study is to develop a typhoon swell forecasting and coastal flooding early warning system by integrating existing sea-state monitoring technology, numerical ocean forecasting models, historical database and experiences, as well as computer science. The proposed system has capability offering data for the past, information for the present, and for the future. The system was developed for Taiwanese coast due to its frequent threat by typhoons. An operational system without any manual work is the basic requirement of the system. Integration of various data source is the system kernel. Numerical ocean models play the important role within the system because they provide data for assessment of possible typhoon swell and flooding. The system includes regional wave model (SWAN) which nested with the large domain wave model (NWW III), is operationally set up for coastal waves forecasting, especially typhoon swell forecasting before typhoon coming, and the storm surge predicted by a POM model. Data assimilation technology is incorporated for enhanced accuracy. A warning signal is presented when the storm water level that accumulated from astronomical tide, storm surge, and wave-induced run-up exceeds the alarm sea level. This warning system has been in practical use for coastal flooding damage mitigation in Taiwan for years. Example of the system operation during Typhoon Haitung struck Taiwan in 2005 is illustrated in this study.

  20. Nanoscale Swelling Heterogeneities in Type I Collagen Fibrils.

    PubMed

    Spitzner, Eike-Christian; Röper, Stephanie; Zerson, Mario; Bernstein, Anke; Magerle, Robert

    2015-06-23

    The distribution of water within the supramolecular structure of collagen fibrils is important for understanding their mechanical properties as well as the biomineralization processes in collagen-based tissues. We study the influence of water on the shape and the mechanical properties of reconstituted fibrils of type I collagen on the nanometer scale. Fibrils adsorbed on a silicon substrate were imaged with multiset point intermittent contact (MUSIC)-mode atomic force microscopy (AFM) in air at 28% relative humidity (RH) and in a hydrated state at 78% RH. Our data reveal the differences in the water uptake between the gap and overlap regions during swelling. This provides direct evidence for different amounts of bound and free water within the gap and overlap regions. In the dry state, the characteristic D-band pattern visible in AFM images is due to height corrugations along a fibril's axis. In the hydrated state, the fibril's surface is smooth and the D-band pattern reflects the different mechanical properties of the gap and overlap regions. PMID:25961780

  1. MOELCULAR SIZE EXCLUSION BY SOIL ORGANIC MATERIALS ESTIMATED FROM THEIR SWELLING IN ORGANIC SOLVENTS

    EPA Science Inventory

    A published method previously developed to measure the swelling characteristics of pow dered coal samples has been adapted for swelling measurements on various peat, pollen, chain, and cellulose samples The swelling of these macromolecular materials is the volumetric manifestatio...

  2. Swelling-induced and controlled curving in layered gel beams

    PubMed Central

    Lucantonio, A.; Nardinocchi, P.; Pezzulla, M.

    2014-01-01

    We describe swelling-driven curving in originally straight and non-homogeneous beams. We present and verify a structural model of swollen beams, based on a new point of view adopted to describe swelling-induced deformation processes in bilayered gel beams, that is based on the split of the swelling-induced deformation of the beam at equilibrium into two components, both depending on the elastic properties of the gel. The method allows us to: (i) determine beam stretching and curving, once assigned the characteristics of the solvent bath and of the non-homogeneous beam, and (ii) estimate the characteristics of non-homogeneous flat gel beams in such a way as to obtain, under free-swelling conditions, three-dimensional shapes. The study was pursued by means of analytical, semi-analytical and numerical tools; excellent agreement of the outcomes of the different techniques was found, thus confirming the strength of the method. PMID:25383031

  3. Apparatus measures swelling of membranes in electrochemical cells

    NASA Technical Reports Server (NTRS)

    Hennigan, T. J.

    1965-01-01

    Apparatus consisting of a pressure plate unit, four springs of known spring constant and a micrometer measures the swelling and force exerted by the polymer membranes of alkaline electrochemical cells.

  4. Fission induced swelling of U-Mo/Al dispersion fuel

    NASA Astrophysics Data System (ADS)

    Kim, Yeon Soo; Jeong, G. Y.; Park, J. M.; Robinson, A. B.

    2015-10-01

    Fission-induced swelling of U-Mo/Al dispersion fuel meat was measured using microscopy images obtained from post-irradiation examination. The data of reduced-size plate-type test samples and rod-type test samples were employed for this work. A model to predict the meat swelling of U-Mo/Al dispersion fuel was developed. This model is composed of several submodels including a model for interaction layer (IL) growth between U-Mo and Al matrix, a model for IL thickness to IL volume conversion, a correlation for the fission-induced swelling of U-Mo alloy particles, a correlation for the fission-induced swelling of IL, and models of U-Mo and Al consumption by IL growth. The model was validated using full-size plate data that were not included in the model development.

  5. Generation of Continental Rifts, Basins and Swells by Lithosphere Instabilities

    NASA Astrophysics Data System (ADS)

    Milelli, L.; Fourel, L.; Jaupart, C. P.

    2012-12-01

    blocks of finite size that became unstable due to cooling from above and describe the peculiar horizontal planform that developed. Dynamical behaviour depends on three dimensionless numbers, a Rayleigh number for the unstable block, a buoyancy number that scales the intrinsic density contrast to the thermal one and the aspect ratio of the block. Within the block, instability develops in two different ways in an outer annulus and in an inner region. In the outer annulus, upwellings and downwellings take the form of radial rolls spaced regularly. In the interior region, the planform adopts the more familiar form of polygonal cells. Translated to geological conditions, such instabilities should manifest themselves as linear rifts striking at a right angle to the continent-ocean boundary and an array of domal uplifts, volcanic swells and basins in the continental interior. The laboratory data lead to simple scaling laws for the dimensions and spacings of the convective structures. For the sub-continental lithospheric mantle, these dimensions and distances take values in the 500-1000 km range, close to geological examples. The large intrinsic buoyancy of Archean lithospheric roots prevents this type of instability, which explains why the widespread volcanic activity that currently affects Western Africa is confined to post-Archean domains.

  6. Altered astrocytic swelling in the cortex of α-syntrophin-negative GFAP/EGFP mice.

    PubMed

    Anderova, Miroslava; Benesova, Jana; Mikesova, Michaela; Dzamba, David; Honsa, Pavel; Kriska, Jan; Butenko, Olena; Novosadova, Vendula; Valihrach, Lukas; Kubista, Mikael; Dmytrenko, Lesia; Cicanic, Michal; Vargova, Lydia

    2014-01-01

    Brain edema accompanying ischemic or traumatic brain injuries, originates from a disruption of ionic/neurotransmitter homeostasis that leads to accumulation of K(+) and glutamate in the extracellular space. Their increased uptake, predominantly provided by astrocytes, is associated with water influx via aquaporin-4 (AQP4). As the removal of perivascular AQP4 via the deletion of α-syntrophin was shown to delay edema formation and K(+) clearance, we aimed to elucidate the impact of α-syntrophin knockout on volume changes in individual astrocytes in situ evoked by pathological stimuli using three dimensional confocal morphometry and changes in the extracellular space volume fraction (α) in situ and in vivo in the mouse cortex employing the real-time iontophoretic method. RT-qPCR profiling was used to reveal possible differences in the expression of ion channels/transporters that participate in maintaining ionic/neurotransmitter homeostasis. To visualize individual astrocytes in mice lacking α-syntrophin we crossbred GFAP/EGFP mice, in which the astrocytes are labeled by the enhanced green fluorescent protein under the human glial fibrillary acidic protein promoter, with α-syntrophin knockout mice. Three-dimensional confocal morphometry revealed that α-syntrophin deletion results in significantly smaller astrocyte swelling when induced by severe hypoosmotic stress, oxygen glucose deprivation (OGD) or 50 mM K(+). As for the mild stimuli, such as mild hypoosmotic or hyperosmotic stress or 10 mM K(+), α-syntrophin deletion had no effect on astrocyte swelling. Similarly, evaluation of relative α changes showed a significantly smaller decrease in α-syntrophin knockout mice only during severe pathological conditions, but not during mild stimuli. In summary, the deletion of α-syntrophin markedly alters astrocyte swelling during severe hypoosmotic stress, OGD or high K(+). PMID:25426721

  7. Altered Astrocytic Swelling in the Cortex of α-Syntrophin-Negative GFAP/EGFP Mice

    PubMed Central

    Anderova, Miroslava; Benesova, Jana; Mikesova, Michaela; Dzamba, David; Honsa, Pavel; Kriska, Jan; Butenko, Olena; Novosadova, Vendula; Valihrach, Lukas; Kubista, Mikael; Dmytrenko, Lesia; Cicanic, Michal; Vargova, Lydia

    2014-01-01

    Brain edema accompanying ischemic or traumatic brain injuries, originates from a disruption of ionic/neurotransmitter homeostasis that leads to accumulation of K+ and glutamate in the extracellular space. Their increased uptake, predominantly provided by astrocytes, is associated with water influx via aquaporin-4 (AQP4). As the removal of perivascular AQP4 via the deletion of α-syntrophin was shown to delay edema formation and K+ clearance, we aimed to elucidate the impact of α-syntrophin knockout on volume changes in individual astrocytes in situ evoked by pathological stimuli using three dimensional confocal morphometry and changes in the extracellular space volume fraction (α) in situ and in vivo in the mouse cortex employing the real-time iontophoretic method. RT-qPCR profiling was used to reveal possible differences in the expression of ion channels/transporters that participate in maintaining ionic/neurotransmitter homeostasis. To visualize individual astrocytes in mice lacking α-syntrophin we crossbred GFAP/EGFP mice, in which the astrocytes are labeled by the enhanced green fluorescent protein under the human glial fibrillary acidic protein promoter, with α-syntrophin knockout mice. Three-dimensional confocal morphometry revealed that α-syntrophin deletion results in significantly smaller astrocyte swelling when induced by severe hypoosmotic stress, oxygen glucose deprivation (OGD) or 50 mM K+. As for the mild stimuli, such as mild hypoosmotic or hyperosmotic stress or 10 mM K+, α-syntrophin deletion had no effect on astrocyte swelling. Similarly, evaluation of relative α changes showed a significantly smaller decrease in α-syntrophin knockout mice only during severe pathological conditions, but not during mild stimuli. In summary, the deletion of α-syntrophin markedly alters astrocyte swelling during severe hypoosmotic stress, OGD or high K+. PMID:25426721

  8. Curcumin micelles improve mitochondrial function in neuronal PC12 cells and brains of NMRI mice - Impact on bioavailability.

    PubMed

    Hagl, Stephanie; Kocher, Alexa; Schiborr, Christina; Kolesova, Natalie; Frank, Jan; Eckert, Gunter P

    2015-10-01

    Curcumin, a polyphenolic compound abundant in the rhizome of Curcuma longa, has been reported to have various beneficial biological and pharmacological activities. Recent research revealed that curcumin might be valuable in the prevention and therapy of numerous disorders including neurodegenerative diseases like Alzheimer's disease. Due to its low absorption and quick elimination from the body, curcumin bioavailability is rather low which poses major problems for the use of curcumin as a therapeutic agent. There are several approaches to ameliorate curcumin bioavailability after oral administration, amongst them simultaneous administration with secondary plant compounds, micronization and micellation. We examined bioavailability in vivo in NMRI mice and the effects of native curcumin and a newly developed curcumin micelles formulation on mitochondrial function in vitro in PC12 cells and ex vivo in isolated mouse brain mitochondria. We found that curcumin micelles improved bioavailability of native curcumin around 10- to 40-fold in plasma and brain of mice. Incubation with native curcumin and curcumin micelles prevented isolated mouse brain mitochondria from swelling, indicating less mitochondrial permeability transition pore (mPTP) opening and prevention of injury. Curcumin micelles proved to be more efficient in preventing mitochondrial swelling in isolated mouse brain mitochondria and protecting PC12 cells from nitrosative stress than native curcumin. Due to their improved effectivity, curcumin micelles might be a suitable formulation for the prevention of mitochondrial dysfunction in brain aging and neurodegeneration.

  9. Molecular accessibility in solvent swelled coal. Quarterly report, November 1991

    SciTech Connect

    Kispert, L.D.

    1991-12-31

    The EPR-spin probe method was used to study the swelling of covalently cross-linked 2%, 4%, 6%, 8% and 12% polystyrene-divinyl benzene copolymers, used as models of APCS coal structural elements. The results were compared with swelling studies on APCS coals and confirmed results showing that coal was polymeric, that it had covalent cross-links increasing with rank, that it was structurally anisotropic, and that its swelling was anisotropic. The low temperature swelling of Argonne Premium Coal Samples using solvents of varying polarity was investigated. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities. The structural changes in coal pores that occur when APCS coal is dehydrated prior to swelling with polar solvents has been determined. These changes are different from those that occur in the absence of prior dehydration. Most impressive is the huge change that occurs in lignite coal (Beulah-Zap). It appears that this coal has collapsed upon dehydration preventing any spin probe from being trapped in the dehydrated lignite upon swelling. Various sized probes have been studied. A study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents has also been completed. A statistical analysis of the data has been completed to determine important trends in the data. 9 refs.

  10. Swelling of four glove materials challenged by six metalworking fluids.

    PubMed

    Xu, Wenhai; Que Hee, Shane S

    2008-01-01

    The performance of protective gloves against metalworking fluids (MWFs) has rarely been studied because of the difficult chemical analysis associated with complex MWFs. In the present study, glove swelling was used as a screening parameter of glove compatibility after challenge of the outer surfaces of chloroprene, latex, nitrile, and vinyl disposable gloves by six MWF concentrates for 2 hours in an ASTM F-739-type permeation cell without collection medium. Swelling relative to original thickness was up to 39% for latex, 7.6% for chloroprene, and 3.5% for nitrile. Shrinking up to 9.3% occurred for vinyl. Chloroprene and latex did not swell significantly for the semisynthetic and synthetic MWFs. Vinyl, previously not tested, was a good candidate for MWFs other than the soluble oil type. Although nitrile was recommended by the National Institute for the Occupational Safety and Health (NIOSH) for all types of MWFs, its swelling after 2-hour challenge was significant with Student t-tests for the soluble oil, synthetic, and semisynthetic MWFs. Glove swelling can be used as a screening chemical degradation method for mixtures such as MWFs with difficult chemical analysis. Further studies need to be conducted on the relationship between permeation and glove swelling.

  11. Rate dependence of swelling in lithium-ion cells

    SciTech Connect

    Oh, KY; Siegel, JB; Secondo, L; Kim, SU; Samad, NA; Qin, JW; Anderson, D; Garikipati, K; Knobloch, A; Epureanu, BI; Monroe, CW; Stefanopoulou, A

    2014-12-01

    Swelling of a commercial 5 Ah lithium-ion cell with a nickel/manganese/cobalt-oxide cathode is investigated as a function of the charge state and the charge/discharge rate. In combination with sensitive displacement measurements, knowledge of the electrode configuration within this prismatic cell's interior allows macroscopic deformations of the casing to be correlated to electrochemical and mechanical transformations in individual anode/separator/cathode layers. Thermal expansion and interior charge state are both found to cause significant swelling. At low rates, where thermal expansion is negligible, the electrode sandwich dilates by as much as 1.5% as the charge state swings from 0% to 100% because of lithium-ion intercalation. At high rates a comparably large residual swelling was observed at the end of discharge. Thermal expansion caused by joule heating at high discharge rate results in battery swelling. The changes in displacement with respect to capacity at low rate correlate well with the potential changes known to accompany phase transitions in the electrode materials. Although the potential response changes minimally with the C-rate, the extent of swelling varies significantly, suggesting that measurements of swelling may provide a sensitive gauge for characterizing dynamic operating states. (C) 2014 Elsevier B.V. All rights reserved.

  12. Swelling of four glove materials challenged by six metalworking fluids.

    PubMed

    Xu, Wenhai; Que Hee, Shane S

    2008-01-01

    The performance of protective gloves against metalworking fluids (MWFs) has rarely been studied because of the difficult chemical analysis associated with complex MWFs. In the present study, glove swelling was used as a screening parameter of glove compatibility after challenge of the outer surfaces of chloroprene, latex, nitrile, and vinyl disposable gloves by six MWF concentrates for 2 hours in an ASTM F-739-type permeation cell without collection medium. Swelling relative to original thickness was up to 39% for latex, 7.6% for chloroprene, and 3.5% for nitrile. Shrinking up to 9.3% occurred for vinyl. Chloroprene and latex did not swell significantly for the semisynthetic and synthetic MWFs. Vinyl, previously not tested, was a good candidate for MWFs other than the soluble oil type. Although nitrile was recommended by the National Institute for the Occupational Safety and Health (NIOSH) for all types of MWFs, its swelling after 2-hour challenge was significant with Student t-tests for the soluble oil, synthetic, and semisynthetic MWFs. Glove swelling can be used as a screening chemical degradation method for mixtures such as MWFs with difficult chemical analysis. Further studies need to be conducted on the relationship between permeation and glove swelling. PMID:17680173

  13. Competition between adsorption-induced swelling and elastic compression of coal at CO2 pressures up to 100 MPa

    NASA Astrophysics Data System (ADS)

    Hol, Sander; Spiers, Christopher J.

    2012-11-01

    Enhanced Coalbed Methane production (ECBM) by CO2 injection frequently proves ineffective due to rapidly decreasing injectivity. Adsorption-induced swelling of the coal matrix has been identified as the principal factor controlling this reduction. To improve understanding of coal swelling in response to exposure to CO2 at high pressures, numerous laboratory studies have been performed in the past decades. These studies consistently reveal an increase in swelling with CO2 pressure. However, it remains unclear what the relative contributions are of adsorption-induced swelling versus elastic compression of the coal framework, and hence what is the true relationship between adsorption-induced swelling and CO2 uptake. Here, we report the results of dilatometry experiments conducted on unconfined, cylindrical coal matrix samples (˜4 mm long and 4 mm in diameter) of high volatile bituminous coal, where we aim to measure the effective volumetric effect of CO2 and to separate this into a component caused by adsorption-induced swelling and a component caused by elastic compression. The experiments were performed using a high pressure eddy current dilatometer that was used to measure one-dimensional sample expansion or contraction (resolution <50 nm). The tests were conducted at a constant temperature of 40 °C, and CO2 pressures up to 100 MPa. Our results show that the matrix samples reveal anisotropic expansion over the full range of CO2 pressures used. Expansion perpendicular to the bedding was about 1.4 times the average expansion measured in the bedding plane. Net volumetric strains, which were computed from the net linear strain in all directions measured, reveal that the response of coal is characterised by an expansion-dominated stage below 10-20 MPa of CO2 pressure and a contraction-dominated stage at higher CO2 pressures. Our data demonstrate direct competition between adsorption-induced swelling and elastic compression in the coal matrix. We propose a model for

  14. Investigation of Molecular Structure of Porous Epoxy Thermosets via Swelling and Glass Transition Behavior

    NASA Astrophysics Data System (ADS)

    Sharifi, Majid; Ghorpade, Kaustubh; Raman, Vijay; Palmese, Giuseppe

    2014-05-01

    Many of the excellent properties of highly crosslinked polymers are due to their molecular structures. In this study, network structures of three epoxy systems, Epon828-PACM, Epon836-PACM, and Epon1001F-PACM were investigated via equilibrium swelling theory. Each systems separately cured in presence of an inert solvent, THF, ranging from 0 to 92% by volume fraction of solvent. Experimental results showed that the conventional swelling theory is valid for specimens polymerized in moderate dilute environments, i.e. up to around 60% solvent by vol. whereas in extremely dilute environments, i.e. above 60%, the computed Mc values are exponentially increasing. This drastic increase in Mc was investigated by Tg measurement of the polymer phase (on supercritically dried specimens). The measured Mc could not predict the corresponding Tg values according to Fox equation. Due to the highly porous nature of the resulting thermosets after supercritical drying, a modifying factor, based on the probability of finding elastic chains in a porous network, was incorporated in the conventional swelling model (Bray-Merrill equation). It was shown that the adjusted Mc values of each thermoset and the corresponding Tgs are acceptably match via the well-known Fox equation. The modified Mc values indicate that, polymer networks produced in presence of miscible inert phases have relatively uniform molecular weight between crosslinks, irrespective of the amount of that inert phase.

  15. Cardiac arrest due to airway obstruction in hereditary angioedema.

    PubMed

    Fuse, Takashi; Nakada, Taka-aki; Taniguchi, Masashi; Mizushima, Yasuaki; Matsuoka, Tetsuya

    2015-12-01

    Hereditary angioedema (HAE) is a rare genetic disease caused by a deficiency of functional C1 esterase inhibitor that causes swelling attacks in various body tissues. We hereby report a case of out-of-hospital cardiac arrest due to airway obstruction in HAE. Cutaneous swelling and abdominal pain attacks caused by gastrointestinal wall swelling are common symptoms in HAE, whereas laryngeal swelling is rare. Emergency physicians may have few chances to experience cases of life-threatening laryngeal edema resulting in a delay from symptom onset to the diagnosis of HAE. Hereditary angioedema is diagnosed by performing complement blood tests. Because safe and effective treatment options are available for the life-threatening swellings in HAE, the diagnosis potentially reduces the risk of asphyxiation in patients and their blood relatives.

  16. Efavirenz and Metabolites in Cerebrospinal Fluid: Relationship with CYP2B6 c.516G→T Genotype and Perturbed Blood-Brain Barrier Due to Tuberculous Meningitis

    PubMed Central

    Chau, Tran Thi Hong; Fisher, Martin; Nelson, Mark; Winston, Alan; Else, Laura; Carr, Daniel F.; Taylor, Steven; Ustianowski, Andrew; Back, David; Pirmohamed, Munir; Solomon, Tom; Farrar, Jeremy; Törok, M. Estée; Khoo, Saye

    2016-01-01

    Efavirenz (EFZ) has been associated with neuropsychiatric side effects. Recently, the 8-hydroxy-EFZ (8OH-EFZ) metabolite has been shown to be a potent neurotoxin in vitro, inducing neuronal damage at concentrations of 3.3 ng/ml. EFZ induced similar neuronal damage at concentrations of 31.6 ng/ml. We investigated the effect of genotype and blood-brain barrier integrity on EFZ metabolite concentrations in cerebrospinal fluid (CSF). We measured CSF drug concentrations in subjects from two separate study populations: 47 subjects with tuberculous meningitis (TBM) coinfection in Vietnam receiving 800 mg EFZ with standard antituberculous treatment and 25 subjects from the PARTITION study in the United Kingdom without central nervous system infection receiving 600 mg EFZ. EFZ and metabolite concentrations in CSF and plasma were measured and compared with estimates of effectiveness and neurotoxicity from available published in vitro and in vivo data. The effect of the CYP2B6 c.516G→T genotype (GG genotype, fast EFV metabolizer status; GT genotype, intermediate EFV metabolizer status; TT genotype, slow EFV metabolizer status) was examined. The mean CSF concentrations of EFZ and 8OH-EFZ in the TBM group were 60.3 and 39.3 ng/ml, respectively, and those in the no-TBM group were 15.0 and 5.9 ng/ml, respectively. Plasma EFZ and 8OH-EFZ concentrations were similar between the two groups. CSF EFZ concentrations were above the in vitro toxic concentration in 76% of samples (GG genotype, 61%; GT genotype, 90%; TT genotype, 100%) in the TBM group and 13% of samples (GG genotype, 0%; GT genotype, 18%; TT genotype, 50%) in the no-TBM group. CSF 8OH-EFZ concentrations were above the in vitro toxic concentration in 98% of the TBM group and 87% of the no-TBM group; levels were independent of genotype but correlated with the CSF/plasma albumin ratio. Potentially neurotoxic concentrations of 8OH-EFZ are frequently observed in CSF independently of the CYP2B6 genotype, particularly in those

  17. The Goodman swell: a lithospheric flexure caused by crustal loading along the Midcontinent rift system

    USGS Publications Warehouse

    Peterman, Z.E.; Sims, P.K.

    1988-01-01

    Rb-Sr biotite ages of Archean and Early to Middle Proterozoic crystalline rocks in northern Wisconsin and adjacent Upper Peninsula of Michigan describe a regionally systematic pattern related to differential uplift. An "age low' occurs in northern Wisconsin where values range from 1070-1172 Ma for rocks with crystallization ages of 1760 to 1865 Ma. These values overlap with the main episode of mafic igneous activity (1090 to 1120 Ma) along the Midcontinent rift system (MRS). We interpret these low biotite ages as registering closure due to cooling below the 300??C isotherm as a consequence of uplift and rapid erosion of an area that we are informally naming the Goodman swell. We interpret the swell to be a forebulge imposed on an elastic crust by loading of mafic igneous rocks along and within the axis of the MRS. -from Authors

  18. Hydrogel-swelling driven delivery device for corrosion resistance of metal in water.

    PubMed

    Gu, Yu; Yang, Li-Ming; Chen, Jie; Wang, Ling-Ling; Chen, Bin

    2015-01-01

    Corrosion on steel and copper pipes in industry can trigger pollution and weakness due to undesired chemical and biochemical reactions. Too much or too little inhibitor can decrease its efficiency, even causing waste and pollution. In this contribution, an innovative delivery device driven by hydrogel swelling, mainly consisting of a semi-permeable membrane, a hydrogel-swelling force drive and a release orifice, was developed to control the release of inhibitor in a water system at a constant rate, leading the amount of inhibitor to maintain a proper concentration. The effects of hydrogel mass and orifice dimension on release property were studied for controlling release rate. Moreover, a weight loss experiment on carbon steels was carried out to show the incredible anti-corrosion function of the system.

  19. Hydrogel-swelling driven delivery device for corrosion resistance of metal in water.

    PubMed

    Gu, Yu; Yang, Li-Ming; Chen, Jie; Wang, Ling-Ling; Chen, Bin

    2015-01-01

    Corrosion on steel and copper pipes in industry can trigger pollution and weakness due to undesired chemical and biochemical reactions. Too much or too little inhibitor can decrease its efficiency, even causing waste and pollution. In this contribution, an innovative delivery device driven by hydrogel swelling, mainly consisting of a semi-permeable membrane, a hydrogel-swelling force drive and a release orifice, was developed to control the release of inhibitor in a water system at a constant rate, leading the amount of inhibitor to maintain a proper concentration. The effects of hydrogel mass and orifice dimension on release property were studied for controlling release rate. Moreover, a weight loss experiment on carbon steels was carried out to show the incredible anti-corrosion function of the system. PMID:26676016

  20. Swelling or erosion on the surface of patterned GaN damaged by heavy ion implantation

    SciTech Connect

    Gao, Yuan; Lan, Chune; Xue, Jianming; Yan, Sha; Wang, Yugang; Xu, Fujun; Shen, Bo; Zhang, Yanwen

    2010-06-08

    Wurtzite undoped GaN epilayers (0 0 0 1) was implanted with 500 keV Au+ ions at room temperature under different doses, respectively. Ion implantation was performed through photoresist masks on GaN to produce alternating strips. The experimental results showed that the step height of swelling and decomposition in implanted GaN depended on ion dose and annealing temperature, i.e., damage level and its evolution. This damage evolution is contributed to implantation-induced defect production, and defect migration/accumulation occurred at different levels of displacement per atom. The results suggest that the swelling is due to the formation of porous structures in the amorphous region of implanted GaN. The decomposition of implanted area can be attributed to the disorder saturation and the diffusion of surface amorphous layer.

  1. Magnetic relaxation -- coal swelling, extraction, pore size. Quarterly technical progress report, October 1, 1993--December 31, 1993

    SciTech Connect

    Doetschman, D.C.

    1993-12-31

    During this quarter, the CW (continuous wave) and pulsed EPR (electron paramagnetic resonance) have been examined of the swelled Argonne Premium whole coals and the swelled residues of these coals. The CW EPR spectra will not be of high quality due to the unexpectedly microwave-lossy character of the pyridine used for swelling. Being relatively unaffected by this characteristic, the pulsed EPR measurements of the spin relaxation times of the broad (non-inertinite) and narrow (inertinite) macerals have been completed. Although detailed analyses of these results have not yet been done, marked differences have been found between the relaxation times of the swelled and unswelled coals and residues. The most startling are the less than 200 nsec times T{sub 1} of the spin-lattice relaxation of the inertinite radicals in the swelled samples. The T{sub 1} of this maceral in the unswelled coal were approaching 1 millisecond. The T{sub 1} contrast was much less pronounced between the swelled and non-swelled non-inertinite macerals. The prospects of significant progress in coal pore size measurements with xenon and NMR (nuclear magnetic resonance) have dimmed since the beginning of this project. This assessment is based on the dearth of these types of studies, a paper at a contractors` meeting on this subject that did not materialize, and discussions with colleagues with experience with the technique in coals. Instead, the authors have been developing a pulsed EPR technique for the spin probing of molecular motion to be applied to pores in carbonaceous materials. This report contains a copy of a nearly final draft of a paper being prepared on the development of this technique, entitled {open_quotes}Physical Characterization of the State of Motion of the Phenalenyl Spin Probe in Cation-Exchanged Faujasite Zeolite Supercages with Pulsed EPR.{close_quotes}

  2. [Reduction of postoperative swelling. Objective measurement of swelling of the upper ankle joint in treatment with serrapeptase-- a prospective study].

    PubMed

    Esch, P M; Gerngross, H; Fabian, A

    1989-02-10

    Using a quantitative standardized procedure, the swelling of the ankle produced by supination trauma was measured. In the 66 patients with fresh rupture of the lateral ligament treated surgically at our Department between December 1986 and April 1987, a prospective study of the effect of serrapeptase (Aniflazym) on post-operative swelling and pain was carried out in 3 randomized groups of patients. In the group receiving the test substance, the swelling had decreased by 50% on the third post-operative day, while in the other two control groups (elevation of the leg, bed rest, with and without the application of ice) no reduction in swelling had occurred at that time. The difference is statistically significant (p = 0.013). Decreasing pain correlated for the most part with the reduction in swelling. Thus, the patients receiving the test substance more rapidly became pain-free than did the control groups. On the basis of these results, serrapeptase would appear to be an effective preparation for the post-operative reduction of swelling, in comparison with the classical conservative measures, for example, the application of ice.

  3. Coupled thermo-hydro-chemical models of swelling bentonites

    NASA Astrophysics Data System (ADS)

    Samper, Javier; Mon, Alba; Zheng, Liange; Montenegro, Luis; Naves, Acacia; Pisani, Bruno

    2014-05-01

    The disposal of radioactive waste in deep geological repositories is based on the multibarrier concept of retention of the waste by a combination of engineered and geological barriers. The engineered barrier system (EBS) includes the solid conditioned waste-form, the waste container, the buffer made of materials such as clay, grout or crushed rock that separate the waste package from the host rock and the tunnel linings and supports. The geological barrier supports the engineered system and provides stability over the long term during which time radioactive decay reduces the levels of radioactivity. The strong interplays among thermal (T), hydrodynamic (H), mechanical (M) and chemical (C) processes during the hydration, thermal and solute transport stages of the engineered barrier system (EBS) of a radioactive waste repository call for coupled THMC models for the metallic overpack, the unsaturated compacted bentonite and the concrete liner. Conceptual and numerical coupled THMC models of the EBS have been developed, which have been implemented in INVERSE-FADES-CORE. Chemical reactions are coupled to the hydrodynamic processes through chemical osmosis (C-H coupling) while bentonite swelling affects solute transport via changes in bentonite porosity changes (M-H coupling). Here we present THMC models of heating and hydration laboratory experiments performed by CIEMAT (Madrid, Spain) on compacted FEBEX bentonite and numerical models for the long-term evolution of the EBS for 1 Ma. The changes in porosity caused by swelling are more important than those produced by the chemical reactions during the early evolution of the EBS (t < 100 years). For longer times, however, the changes in porosity induced by the dissolution/precipitation reactions are more relevant due to: 1) The effect of iron mineral phases (corrosion products) released by the corrosion of the carbon steel canister; and 2) The hyper alkaline plume produced by the concrete liner. Numerical results show that

  4. Comparison of swelling and cavity microstructural development for type 316 stainless steel irradiated in EBR-II and HFIR

    SciTech Connect

    Maziasz, P.J.

    1983-01-01

    Comparison of swelling and cavity microstructures for one heat of 20% cold-worked (CW) type 316 stainless steel (316) irradiated at 500 to 650/sup 0/C in EBR-II (up to 75 dpa) and HFIR (up to 61 dpa) suggests that void growth and swelling are suppressed by the higher helium generation found in HFIR. Instead of voids, many small bubbles develop in the CW 316 in HFIR and resist conversion to voids. However, similar comparison of solution-annealed (SA) 316 irradiated in EBR-II and HFIR at 500 to 550/sup 0/C leads to an opposite conclusion; void swelling is enhanced by helium in HFIR. Many more bubbles nucleate in SA 316 at low fluence in HFIR compared to EBR-II, but bimodel distributions and rapid coarsening eventually lead to high swelling due to high concentrations of matrix ands precipitate-associated voids in HFIR. A key to the swelling resistance of the CW 316 in HFIR appears to be the development of a sufficiently cavity-dominated sink system in the early stages of evolution.

  5. Void swelling and microstructure evolution at very high damage level in self-ion irradiated ferritic-martensitic steels

    NASA Astrophysics Data System (ADS)

    Getto, E.; Sun, K.; Monterrosa, A. M.; Jiao, Z.; Hackett, M. J.; Was, G. S.

    2016-11-01

    The void swelling and microstructure evolution of ferritic-martensitic alloys HT9, T91 and T92 were characterized following irradiation with Fe++ ions at 460 °C to damage levels of 75-650 displacements per atom with 10 atom parts per million pre-implanted helium. Steady state swelling rate of 0.033%/ dpa was determined for HT9, the least swelling resistant alloy, and 0.007%/ dpa in T91. In T91, resistance was due to suppression of void nucleation. Swelling resistance was greatest in T92, with a low density (∼1 × 1020 m-3) of small voids that had not grown appreciably, indicating suppression of nucleation and growth. Additional heats of T91 indicated that alloy composition was not the determining factor of swelling resistance. Carbon and chromium-rich M2X precipitates formed at 250 dpa and were correlated with decreased nucleation in T91 and T92, but did not affect void growth in HT9. Dislocation and G-phase microstructure evolution was analyzed up to 650 dpa in HT9.

  6. Non-invasive analysis of swelling in polymer dispersions by means of time-domain(TD)-NMR.

    PubMed

    Nestle, Nikolaus; Häberle, Karl

    2009-11-01

    In this contribution, we discuss the potential of low-field time-domain(TD)-NMR to study the swelling of (aqueous) polymer dispersions by a volatile solvent. Due to the sensitivity of transverse relaxation times (T2) to swelling-induced changes in the molecular dynamics of the polymer component, the effects of swelling can be measured without spectral resolution. The measurement is performed on polymer dispersions in native state with solids contents around 50% in a non-invasive way without separating the polymeric phase and the water phase from each other. Using acetone in two polyurethane (PU) dispersions with different hard phase contents, we explore the sensitivity of the method and present a data evaluation strategy based on multicomponent fitting and proton balancing. Furthermore, we report exchange continualization as a further effect that needs to be taken into account for correct interpretation of the data. PMID:19850165

  7. Swelling of root cell walls as an indicator of their functional state.

    PubMed

    Meychik, N R; Yermakov, I P

    2001-02-01

    The swelling capacity of cell walls isolated from different parts of lupine root was investigated. The water content in fragments of intact roots (Q) and swelling coefficient of standardized samples of cell walls (Kcw) were determined, and the dependences of Q and Kcw on the distance from the root tip (L) were plotted. It was shown that the change in Q value along the stretch of the lupine root reaches its maximum at distances of 1.5-6 cm or 7-12 cm from the root tip in 7-day-old and 14-day-old seedlings, respectively, whereas the Kcw value distribution over the root length is virtually invariable. In the radial direction, both the Q and Kcw values in cortex tissues are about twice higher than in the central cylinder. In our opinion, the changes of both Q and Kcw in the radial direction are associated with different degrees of cross-linking between polymer chains in cell wall structures of root cortex and central cylinder. The results of measurement of the Kcw value are consistent with the widely accepted mechanisms of water transport in roots in the radial direction. These data show that water transport through apoplast to the border between the cortex and central cylinder is accompanied by an increase in the resistance to water flow. Among other factors, this increase is due to a greater degree of cross-linking between cell wall polymers in the central cylinder. The results of measurement of the swelling coefficient of standardized cell wall samples in water and in 10 mM KCl at different pH values show that the swelling capacity of root cell walls varies according to the physicochemical properties of synthetic ion exchangers. Cell walls shrink (cell wall volume decreases) as ion concentration in solution increases and pH decreases. This causes an increase in the hydraulic resistance (or a decrease in the hydraulic conductivity) of apoplast. It was concluded that swelling is determined by the physicochemical properties of the cell wall, whereas the change in the

  8. Molecular accessibility in solvent swelled coals. Final report

    SciTech Connect

    Kispert, L.D.

    1994-04-01

    The conversion of coal by an economically feasible catalytic method requires the catalyst to diffuse into the coal sample so that hydrogenation catalysis can occur from within as well as the normal surface catalysis. Thus an estimate of the size, shape, and reactivity, of the pores in the coal before and after the swelling with different solvents is needed so that an optimum sized catalyst will be used. This study characterizes the accessible area found in Argonne Premium Coal Samples (APCS) using a EPR spin probe technique. The properties deduced in this manner correlate well with the findings deduced from SANS, NMR, SEM, SAXS and light scattering measurements. The use of nitroxide spin probes with swelling solvents is a simple way in which to gain an understanding of the pore structure of coals, how it changes in the presence of swelling solvents and the chemistry that occurs at the pore wall. Hydrogen bonding sites occur primarily in low-rank coals and vary in reactive strength as rank is varied. Unswelled coals contain small, spherical pores which disappear when coal is swelled in the presence of polar solvents. Swelling studies of polystyrene-divinyl benzene copolymers implied that coal is polymeric, contains significant quantities of covalent cross-links and the covalent cross-link density increases with rank.

  9. Water state characterization, swelling behavior, thermal and mechanical properties of chitosan based networks.

    PubMed

    Khalid, M N; Agnely, F; Yagoubi, N; Grossiord, J L; Couarraze, G

    2002-06-01

    Two kinds of chitosan-based hydrogels, a crosslinked chitosan reference gel and a chitosan-poly(ethylene oxide) semi-interpenetrating network (semi-IPN), with potential pH-sensitive swelling and drug delivery properties are characterized. Swelling studies were performed on the two kinds of hydrogels by differential scanning calorimetry (DSC) at pH 1.2 and by the gravimetric method at pH 1.2 and pH 7.2. Both methods lead to similar results. If pH-dependent swelling properties were observed with both hydrogels, they were however improved for the semi-IPN. The amount of bound water in the xerogels could be determined from DSC measurements and a thermogravimetric analysis. The results obtained by both techniques were in good agreement and indicated that the semi-IPN contained more bound water than the reference gel probably due to the presence of the hydrophilic poly(ethylene oxide) chains. Young modulus of the swollen hydrogels was determined by indentation analysis. The semi-IPN displayed improved mechanical properties compared to the reference gel.

  10. Clay swelling and formation permeability reductions induced by a nonionic surfactant

    SciTech Connect

    Gardner, K.H.; Arias, M.S.

    2000-01-01

    A major concern with the use of surfactant flushing to mobilize nonaqueous phase liquids in aquifers is specific mineral-surfactant interactions that may effect significant permeability changes in the soil formation. Soils comprised of Ottawa sand mixed with small percentages of bentonite that had moderate initial hydraulic conductivity were investigated for loss of permeability upon flushing with solution containing a nonionic surfactant (polyoxyethylene sorbitan monooleate). Columns containing 0, 1, 2, 3, 4, and 5% had permeability reductions of 1, 5, 13, 44, 49, and 69%, respectively. The surfactant-clay interactions were further investigated as the cause of the permeability reductions. Some transport of clay through the column was apparent from a small amount of release measured. A permeability change was correlated with the colloid transport in the column with the highest clay concentration, although its effect was transient. Clay swelling was postulated as the primary mechanism for the permeability reductions. It was determined through X-ray diffraction that the surfactant was spreading the silica layer spacings of the clay from a hydration spacing of 15.23 {angstrom} to a surfactant-swelled spacing of 18.02 {angstrom}. A model was formulated to describe the reduced permeability by the increase in clay volume due to swelling measured by X-ray diffraction and was capable of describing the observed data well with an average error of approximately 10%.

  11. Swelling equilibria for temperature-sensitive ampholytic hydrogels

    SciTech Connect

    Baker, J.P.; Stephens, D.R.; Blanch, H.W.; Prausnitz, J.M.

    1992-09-01

    Temperature-sensitive N-isopropylacrylamide (NIPA)-based ampho-lytic hydrogels were synthesized by copolymerizing NIPA with the cationic monomer methacrylamidopropyl trimethylammonium chloride (MAPTAC) and the anionic monomer sodium styrene sulfonate (SSS). The total nominal charge density of the hydrogels was held constant at 8 mol % (dry basis), while the molar ratio of anionic to cationic moieties within the hydrogels was varied. Swelling equilibria were measured in water at 6C, and in aqueous sodium chloride solutions ranging in concentration from 10{sup {minus}5}to 5 M and temperature ranging from 6 to 56C. Consistent with expectations, the swelling behavior of the hydrogels was found to be controlled by temperature at low salt concentrations; as the sodium chloride concentration increased, temperature control of hydrogel swelling decreased. Slight antipolyelectrolyte behavior was observed for the hydrogel prepared with equal molar amounts of MAPTAC and SSS.

  12. Depleting depletion: Polymer swelling in poor solvent mixtures

    NASA Astrophysics Data System (ADS)

    Mukherji, Debashish; Marques, Carlos; Stuehn, Torsten; Kremer, Kurt

    A polymer collapses in a solvent when the solvent particles dislike monomers more than the repulsion between monomers. This leads to an effective attraction between monomers, also referred to as depletion induced attraction. This attraction is the key factor behind standard polymer collapse in poor solvents. Strikingly, even if a polymer exhibits poor solvent condition in two different solvents, it can also swell in mixtures of these two poor solvents. This collapse-swelling-collapse scenario is displayed by poly(methyl methacrylate) (PMMA) in aqueous alcohol. Using molecular dynamics simulations of a thermodynamically consistent generic model and theoretical arguments, we unveil the microscopic origin of this phenomenon. Our analysis suggests that a subtle interplay of the bulk solution properties and the local depletion forces reduces depletion effects, thus dictating polymer swelling in poor solvent mixtures.

  13. Geoid height versus topography for oceanic plateaus and swells

    NASA Technical Reports Server (NTRS)

    Sandwell, David T.; Mackenzie, Kevin R.

    1989-01-01

    Gridded geoid height data (Marsh et al.l, 1986) and gridded bathymetry data (Van Wykhouse, 1973) are used to estimate the average compensation depths of 53 oceanic swells and plateaus. The relationship between geoid height and topography is examined using Airy and thermal compensation models. It is shown that geoid height is linearly related to topography between wavelengths of 400 and 4000 m as predicted by isostatic compensation models. The geoid/topography ratio is dependent on the average depth of compensation. The intermediate geoid/topography ratios of most thermal swells are interpreted as a linear combination of the decaying thermal swell signature and that of the persisting Airy-compensated volcanic edifice.

  14. Swelling of several commercial alloys following high fluence neutron irradiation

    SciTech Connect

    Powell, R.W.; Peterson, D.T.; Zimmerschied, M.K.; Bates, J.F.

    1981-01-01

    Swelling values have been determined for a set of commercial alloys irradiated to a peak fluence of 17.8 x 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV) over the temperature range of 400 to 650/sup 0/C. The alloys studied fall into three classes: the ferritic alloys AISI 430F, AISI 416, EM-12, H-11 and 2 1/4 Cr-1 Mo; the superalloys Inconel 718 and Inconel X-750; and the refractory alloys TZM and Nb-1 Zr. After irradiation to a peak fluence approaching goal exposures envisioned for advanced fusion reactor first walls, all of the alloys display swelling resistance far superior to cold worked AISI 316. Of the three alloy classes examined the swelling resistance of the ferritics is the least sensitive to composition.

  15. Adsorption and strain: The CO 2-induced swelling of coal

    NASA Astrophysics Data System (ADS)

    Vandamme, M.; Brochard, L.; Lecampion, B.; Coussy, O.

    2010-10-01

    Enhanced coal bed methane recovery (ECBM) consists in injecting carbon dioxide in coal bed methane reservoirs in order to facilitate the recovery of the methane. The injected carbon dioxide gets adsorbed at the surface of the coal pores, which causes the coal to swell. This swelling in confined conditions leads to a closure of the coal reservoir cleat system, which hinders further injection. In this work we provide a comprehensive framework to calculate the macroscopic strains induced by adsorption in a porous medium from the molecular level. Using a thermodynamic approach we extend the realm of poromechanics to surface energy and surface stress. We then focus on how the surface stress is modified by adsorption and on how to estimate adsorption behavior with molecular simulations. The developed framework is here applied to the specific case of the swelling of CO 2-injected coal, although it is relevant to any problem in which adsorption in a porous medium causes strains.

  16. Strain localization in ductile rocks: A comparison of natural and simulated pinch-and-swell structures

    NASA Astrophysics Data System (ADS)

    Peters, Max; Berger, Alfons; Herwegh, Marco; Regenauer-Lieb, Klaus

    2016-06-01

    We study pinch-and-swell structures in order to uncover the onset of strain localization and the change of deformation mechanisms in layered ductile rocks. To this end, boudinaged monomineralic veins embedded in an ultramylonitic matrix are analyzed quantitatively. The swells are built up by relatively undeformed original calcite grains, showing twinning and minor subgrain rotation recrystallization (SGR). Combined with progressive formation of high-angle misorientations between grains, indicative of SGR, severe grain size reduction defines the transition to the pinches. Accordingly, dynamically recrystallized grains have a strong crystallographic preferred orientation (CPO). Toward the necks, further grain size reduction, increasingly random misorientations, nucleation of new grains, and a loss of the CPO occur. We postulate that this microstructure marks the transition from dislocation to diffusion creep induced by strain localization. We confirm that the development of boudins is insensitive to original grain sizes and single-crystal orientations. In order to test these microstructural interpretations, a self-consistent numerical grain size evolution is implemented, based on thermo-mechanical principles, end-member flow laws and microphysical processes. Applying constant velocity and isothermal boundary conditions to a 3-layer finite element pure shear box, pinch-and-swell structures emerge out of the homogeneous layer through grain size softening at a critical state. Viscosity weakening due to elevated strain rates and dissipated heat from grain size reduction promotes strain rate weakening until a critical grain size is reached. At this point, a switch from dislocation to diffusion creep occurs. This state locks in at local steady states and is microstructurally expressed in pinches and swells, respectively. Thus, boudinage is identified as an energy attractor, identifying the high-energy steady state of an extending layered structure. We conclude from the

  17. Non-breaking swell dissipation from synthethic aperture radar

    NASA Astrophysics Data System (ADS)

    Stopa, Justin; Husson, Romain; Ardhuin, Fabrice; Collard, Fabrice; Chapron, Bertrand

    2015-04-01

    Swells have the unique ability to propagate away from their generation region with very little attenuation. Only one study exists in the ocean wave literature that measures the decay rate by following a swell with in-situ measurements along its great circle route. More recently used space-borne synthetic aperture radar (SAR) to measure the attenuation. They estimated the dissipation rate from SAR with a limited number of cases: 11 storms with 22 total events. The present work extrapolates their technique to more events since ENVISAT has collected SAR data from 2002-2012. The dissipation rate is then determined in a two step process. First swell sources are identified from density maps of back-propagated waves at their group velocity along great circles. Next a "point-source" model is assumed and the waves from all directions and frequencies are propagated forward to find matching SAR observations. Relatively small directional bins are used to group observations creating transects from a given swell event. This ensemble of tracks is the basic dataset used to calculate a more statistically robust measure of the dissipation rate. Individual tracks and the swell behavior are explored through this dataset. Our results are in agreement with previous findings and it is verified that swells are very persistent with e-folding scales larger than 20,000 km and they behave nonlinearly as a function of wave frequency. The results are discussed in terms of their implications in spectral wave models as well as identify limitations of the remotely sensed wave spectra. The wind's role on the dissipation rate cannot be determined from this analysis stressing the need for concurrent wind and wave observations.

  18. Menstrual Cycle and Hormonal Contraceptive-Dependent Changes in Intrinsic Connectivity of Resting-State Brain Networks Correspond to Behavioral Changes Due to Hormonal Status.

    PubMed

    Pletzer, Belinda; Crone, Julia Sophia; Kronbichler, Martin; Kerschbaum, Hubert

    2016-09-01

    Menstrual cycle-dependent changes have been reported for a variety of functions, including cognition, attention, emotion, inhibition, and perception. For several of these functions, an effect of hormonal contraceptives has also been discussed. Cognitive, attentional, emotional, inhibitory, and perceptual functions have been linked to distinct intrinsic connectivity networks during the resting state. However, changes in resting-state connectivity across the menstrual cycle phase and due to hormonal contraceptive use have only been investigated in two selected networks and without controlling for the type of hormonal contraceptives. In the present study, we demonstrate menstrual cycle and hormonal contraceptive-dependent changes in several intrinsic connectivity networks, including networks that have been related to emotion processing, olfaction, audition, vision, coordination, and two lateralized frontoparietal networks related to a variety of cognitive functions. These changes parallel behavioral changes in the functions associated with these networks. Changes in connectivity and changes in behavior occur during the same cycle phases. Furthermore, hormonal contraceptive-dependent effects were observed in the same networks and same target sites as menstrual cycle-related changes and were dependent on the androgenicity of the progestin component contained in the hormonal contraceptive.

  19. Swelling of cross-linked polystyrene spheres in toluene vapor

    SciTech Connect

    Zhang, R.; Graf, K.; Berger, R.

    2006-11-27

    The swelling behavior of individual micron-sized polystyrene (PS) spheres in toluene vapor was studied via mass loading by means of micromechanical cantilever sensors. For 4%-8% cross-linked PS a mass increase of 180% in saturated toluene vapor was measured. The mass of the swollen PS sphere decreases with increasing exposure time to ultraviolet light. In addition, the swelling response is significantly different between the first and the second exposure to toluene vapor. This is attributed to the formation of a cross-linked shell at the surface of the PS spheres. Shape persistent parts were observed for locally irradiated PS spheres.

  20. Compression and swelling of activated sludge cakes during dewatering.

    PubMed

    Sveegaard, Steffen Gralert; Keiding, Kristian; Christensen, Morten Lykkegaard

    2012-10-15

    A drainage/filtration apparatus was developed for automatically determining sedimentation velocity and dewatering rate. Pressure-step testing was used to study filter cake compressibility, resistance, and swelling. Activated sludge was analysed, and the data indicate that the sludge is highly compressible even at low pressures (10 kPa). Furthermore, compressed sludge cakes swell if the pressure is released. Hence, the average specific cake resistance decreases if the pressure is released, though the resistance is higher after the compression cycle than before. Sludge must be dewatered under low pressure, because higher pressure only compresses the cake and does not improve the dewatering rate.

  1. Swelling of peat soil samples as determined by 1H NMR relaxometry

    NASA Astrophysics Data System (ADS)

    Jaeger, F.; Schaumann, G. E.

    2009-04-01

    The swelling of soil organic matter (SOM) rich samples like peat soils may affect sorption and desorption of nutrients and contaminants. In the course of swelling the state of water may change and SOM may form a gel phase. Two peat soil samples in different degradation states from one location in Germany were saturated with water. Their swelling kinetics were studied at 5°C, 19°C and 30°C using 1H NMR relaxometry at 7.5 MHz. CPMG pulse sequence and the inversion recovery method were used to determine transverse (T2) and longitudinal (T1) relaxation time distributions, respectively. The gel phase and the state of water were both characterized with 1H NMR relaxometry, Cryo-NMR and differential scanning calorimetry (DSC). Three types of water were found in both peats: Non-freezing bound water and two types of freezable water which showed a splitting of the melting peak in the DSC thermogram. The stepwise water drainage of the peat samples by centrifugation revealed increasing T1/T2 ratios, which were not caused by proton relaxation, due to spin diffusion in internal field gradients. It can be assumed that both the splitting of the melting peak and the increasing T1/T2 ratios were caused by a phase separation of the "free" freezable water as found for conventional biopolymers like starch. Due to the organic surfaces one phase of the freezable water is structured which affects the rotational motion of water molecules, and thus caused different T1 and T2 values. From the swelling kinetics three processes (fast, medium, slow) of water dislocation from larger to smaller T2 values were distinguished. The time constants of the processes were found to be in the range of minutes (fast), hours (medium) and days/weeks (slow). The activation energies ranged between 15 - 50 KJ mol-1 suggesting that physical and physical/chemical processes are governing the swelling of SOM like a sterical re-orientation of SOM macromolecules, the water-structuring and hydration of SOM.

  2. Brain investigation and brain conceptualization

    PubMed Central

    Redolfi, Alberto; Bosco, Paolo; Manset, David; Frisoni, Giovanni B.

    Summary The brain of a patient with Alzheimer’s disease (AD) undergoes changes starting many years before the development of the first clinical symptoms. The recent availability of large prospective datasets makes it possible to create sophisticated brain models of healthy subjects and patients with AD, showing pathophysiological changes occurring over time. However, these models are still inadequate; representations are mainly single-scale and they do not account for the complexity and interdependence of brain changes. Brain changes in AD patients occur at different levels and for different reasons: at the molecular level, changes are due to amyloid deposition; at cellular level, to loss of neuron synapses, and at tissue level, to connectivity disruption. All cause extensive atrophy of the whole brain organ. Initiatives aiming to model the whole human brain have been launched in Europe and the US with the goal of reducing the burden of brain diseases. In this work, we describe a new approach to earlier diagnosis based on a multimodal and multiscale brain concept, built upon existing and well-characterized single modalities. PMID:24139654

  3. Nondestructive Creation of Ordered Nanopores by Selective Swelling of Block Copolymers: Toward Homoporous Membranes.

    PubMed

    Wang, Yong

    2016-07-19

    the increasingly opened nanoporous intermediates, to interconnected networks of micellar nanofibers, and finally to isolated micellar spheres with increasing degrees of swelling. When the BCP films are aligned perpendicularly or in-plane, selective swelling results in uniform "standing" (perpendicular orientation) and "sleeping" (in-plane orientation) pores, respectively. Pore sizes can be tuned by changing molecular weights of the BCPs and swelling conditions without the loss of pore uniformity. Due to the nondestructive nature of this swelling process, nothing in the BCPs is lost during the pore-forming procedure, and consequently the formed pores can be progressively closed also by selective swelling. Such reversible pore opening/closing can be repeated many times, enabling the application of these materials in drug delivery and intelligent antireflective coatings. The monodispersed pore sizes, straight pore profile, and hydrophilic pore walls particularly favor the application of the porous BCPs in separations as homoporous membranes (HOMEs) exhibiting high selectivity, permeability, and inherent stimulus responsiveness. PMID:27349573

  4. How does a flexible chain of active particles swell?

    PubMed

    Kaiser, Andreas; Babel, Sonja; ten Hagen, Borge; von Ferber, Christian; Löwen, Hartmut

    2015-03-28

    We study the swelling of a flexible linear chain composed of active particles by analytical theory and computer simulation. Three different situations are considered: a free chain, a chain confined to an external harmonic trap, and a chain dragged at one end. First, we consider an ideal chain with harmonic springs and no excluded volume between the monomers. The Rouse model of polymers is generalized to the case of self-propelled monomers and solved analytically. The swelling, as characterized by the spatial extension of the chain, scales with the monomer number defining a Flory exponent ν which is ν = 1/2, 0, 1 in the three different situations. As a result, we find that activity does not change the Flory exponent but affects the prefactor of the scaling law. This can be quantitatively understood by mapping the system onto an equilibrium chain with a higher effective temperature such that the chain swells under an increase of the self-propulsion strength. We then use computer simulations to study the effect of self-avoidance on active polymer swelling. In the three different situations, the Flory exponent is now ν = 3/4, 1/4, 1 and again unchanged under self-propulsion. However, the chain extension behaves non-monotonic in the self-propulsion strength.

  5. Swelling and drug release from oral thin films (OTFs)

    NASA Astrophysics Data System (ADS)

    Adrover, A.; Casadei, M. A.; Paolicelli, P.; Petralito, S.; Varani, G.

    2016-05-01

    We investigate the characteristic time-scales for swelling and drug release from polymeric thin films for buccal delivery. In this work, novel OTFs were prepared combining Gellan gum, a natural polysaccharide well known in the pharmaceutical field, along with Glycerol, used as plasticizer. A new millifluidic flow-through device is adopted for in-vitro release tests.

  6. Linear Viscoelasticity and Swelling of Polyelectrolyte Complex Coacervates

    NASA Astrophysics Data System (ADS)

    Hamad, Fawzi; Colby, Ralph

    2012-02-01

    The addition of near equimolar amounts of poly(diallyldimethylammonium chloride) to poly(isobutylene-alt-maleate sodium), results in formation of a polyelectrolyte complex coacervate. Zeta-potential titrations conclude that these PE-complexes are nearly charge-neutral. Swelling and rheological properties are studied at different salt concentrations in the surrounding solution. The enhanced swelling observed at high salt concentration suggests the system behaves like a polyampholyte gel, and weaker swelling at very low salt concentrations implies polyelectrolyte gel behavior. Linear viscoelastic oscillatory shear measurements indicate that the coacervates are viscoelastic liquids and that increasing ionic strength of the medium weakens the electrostatic interactions between charged units, lowering the relaxation time and viscosity. We use the time-salt superposition idea recently proposed by Spruijt, et al., allowing us to construct master curves for these soft materials. Similar swelling properties observed when varying molecular weights. Rheological measurements reveal that PE-complexes with increasing molecular weight polyelectrolytes form a network with higher crosslink density, suggesting time-molecular weight superposition idea.

  7. Impedimetric transduction of swelling in pH-responsive hydrogels.

    PubMed

    Mac Kenna, Nicky; Calvert, Paul; Morrin, Aoife

    2015-05-01

    A pH-responsive hydrogel composed of an aliphatic diamine cross-linked with polyethylene glycol diglycidyl ether (PEGDGE) using a single, rapid polymerisation step has been used to detect glucose by entrapping glucose oxidase (GOx) within its cationic network. The swelling response of hydrogel disks on exposure to glucose were optimised through variation of factors including the cross-linking density of the network, GOx loading and the addition of catalase. Hydrogel-modified carbon cloth electrodes were also prepared and characterised using voltammetric and impedimetric techniques. Non-faradaic electrochemical impedance spectroscopy (EIS) and gravimetry were both employed to track the swelling response of the gels quantitatively. The clear potential of utilising impedance to transduce hydrogel swelling was demonstrated where a linear decrease in gel resistance (Rgel) corresponding to the swelling response was observed in the range 1 to 100 μM. A dramatic increase in the limit of detection of six orders of magnitude over the gravimetric measurement was achieved (from 0.33 mM to 0.08 μM). This increased sensitivity, coupled with the textile-based electrode substrate approach opens the potential applicability of this system for monitoring glucose concentration via the skin by sweat or interstitial fluid (ISF). PMID:25768307

  8. Impedimetric transduction of swelling in pH-responsive hydrogels.

    PubMed

    Mac Kenna, Nicky; Calvert, Paul; Morrin, Aoife

    2015-05-01

    A pH-responsive hydrogel composed of an aliphatic diamine cross-linked with polyethylene glycol diglycidyl ether (PEGDGE) using a single, rapid polymerisation step has been used to detect glucose by entrapping glucose oxidase (GOx) within its cationic network. The swelling response of hydrogel disks on exposure to glucose were optimised through variation of factors including the cross-linking density of the network, GOx loading and the addition of catalase. Hydrogel-modified carbon cloth electrodes were also prepared and characterised using voltammetric and impedimetric techniques. Non-faradaic electrochemical impedance spectroscopy (EIS) and gravimetry were both employed to track the swelling response of the gels quantitatively. The clear potential of utilising impedance to transduce hydrogel swelling was demonstrated where a linear decrease in gel resistance (Rgel) corresponding to the swelling response was observed in the range 1 to 100 μM. A dramatic increase in the limit of detection of six orders of magnitude over the gravimetric measurement was achieved (from 0.33 mM to 0.08 μM). This increased sensitivity, coupled with the textile-based electrode substrate approach opens the potential applicability of this system for monitoring glucose concentration via the skin by sweat or interstitial fluid (ISF).

  9. Shrink-swell behavior of soil across a vertisol catena

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shrinking and swelling of soils and the associated formation and closing of cracks can vary spatially within the smallest hydrologic unit subdivision utilized in surface hydrology models. Usually in the application of surface hydrology models, cracking is not considered to vary within a hydrologic u...

  10. A 47-year-old man with tongue swelling.

    PubMed

    Rodríguez-Roa, Maristely; Nazario, Sylvette; Ramos, Cristina

    2016-07-01

    Intermittent tongue angioedema can be the initial presentation of several disorders including angiotensin-converting-enzyme inhibitor induced angioedema and hereditary angioedema. Persistent angioedema on the other hand, can be associated with amyloidosis, tumors, thyroid disorders and acromegaly. We present a case of intermittent episodes of tongue swelling progressing to macroglossia. PMID:27401321

  11. Lupus erythematosus--a case of facial swelling.

    PubMed

    Loescher, A; Edmondson, H D

    1988-04-01

    A case is reported of acute facial swelling following tooth extraction that failed to respond in a normal manner. The patient developed systemic signs and symptoms ultimately revealing the diagnosis of lupus erythematosus. The possibility of soft tissue lesions arising in some forms of lupus is emphasised by this report. PMID:3163493

  12. The Swelling and Destabilization of a Coronal Mass Ejection (abstract)

    NASA Technical Reports Server (NTRS)

    Martin, S. F.; Feynman, J.

    1993-01-01

    We will present and discuss data for a bugle that was particularly well observed. Apparently the swelling of the bugle and its destabilization were caused by the newly emerging flux and its interaction with the pre-existing active regions and coronal structures.

  13. Demonstration of Solvent Differences by Visible Polymer Swelling.

    ERIC Educational Resources Information Center

    Ross, Joseph H.

    1983-01-01

    Effect of the "polarity" of low-polarity solvents on the amount of swelling produced in a solid polymer (demonstrated in an organic chemistry lecture) is also suitable as a laboratory experiment. Students can be assigned to a small group of solvents from the list provided. Procedures and materials needed are included. (Author/JN)

  14. Urethroscrotal Fistula: A Rare Cause of Scrotal Swelling

    PubMed Central

    Parlak, Selcuk; Okay, Aysun E.

    2016-01-01

    Summary Background Urethroscrotal fistula (USF) is an abnormal communication between the urethra and the scrotum. This rare abnormality may be iatrogenic or secondary to perforation of the urethra by a stone. After the passage of urine to the scrotum through the fistula, painless scrotal swelling develops, which disappears completely with manual compression, and voiding can be maintained in this way. Retrograde urethrography (RU) and voiding cystourethrography (VCU) are traditional diagnostic methods, but they have limitations, such as technical difficulties and inability to evaluate the surrounding tissues. Multidetector CT (MDCT), together with reformatted images, can provide valuable information about the surrounding tissues and associated pathologies. Case Report We present a case of a 36-year-old male patient who had painless scrotal swelling after cystolithotomy and urethral stone surgery. The patient indicated that the swelling disappeared after manual compression. A fistula between the bulbous urethra and the scrotum was discovered by MDCT. In our case, we believe that the fistula developed iatrogenically during stone excision or secondary to perforation of the urethra by a stone. Conclusions As a rare pathology, urethroscrotal fistula should be considered in men with a history of urethral stone surgery and symptoms, including painless scrotal swelling, which can be manually compressed after voiding.

  15. [A former bodybuilder with a swelling on the forearm].

    PubMed

    Strijbos, Ruben M; Zwaard, Ton M

    2015-01-01

    A 56-year-old man came to the general practitioner with a solitary compressible swelling on his left forearm, which enlarged during exercise. The patient reported a history of bodybuilding and he worked as a plasterer. Physical examination revealed primary varicose of the upper extremity, a rare localisation of a common vascular disease.

  16. Urethroscrotal Fistula: A Rare Cause of Scrotal Swelling

    PubMed Central

    Parlak, Selcuk; Okay, Aysun E.

    2016-01-01

    Summary Background Urethroscrotal fistula (USF) is an abnormal communication between the urethra and the scrotum. This rare abnormality may be iatrogenic or secondary to perforation of the urethra by a stone. After the passage of urine to the scrotum through the fistula, painless scrotal swelling develops, which disappears completely with manual compression, and voiding can be maintained in this way. Retrograde urethrography (RU) and voiding cystourethrography (VCU) are traditional diagnostic methods, but they have limitations, such as technical difficulties and inability to evaluate the surrounding tissues. Multidetector CT (MDCT), together with reformatted images, can provide valuable information about the surrounding tissues and associated pathologies. Case Report We present a case of a 36-year-old male patient who had painless scrotal swelling after cystolithotomy and urethral stone surgery. The patient indicated that the swelling disappeared after manual compression. A fistula between the bulbous urethra and the scrotum was discovered by MDCT. In our case, we believe that the fistula developed iatrogenically during stone excision or secondary to perforation of the urethra by a stone. Conclusions As a rare pathology, urethroscrotal fistula should be considered in men with a history of urethral stone surgery and symptoms, including painless scrotal swelling, which can be manually compressed after voiding. PMID:27668028

  17. Anomalous swelling behavior of FM 5055 carbon phenolic composite

    NASA Technical Reports Server (NTRS)

    Stokes, E. H.

    1992-01-01

    The swelling response of a typical carbon phenolic composite was measured in the three primary material directions. The data obtained sugrest that at low and high relative humidities the incremental increase in moisture absorption can be attributed primarily to the resin. At intermediate relative humidities, the water is moving largely into the carbonized fibers.

  18. Advanced liquefaction using coal swelling and catalyst dispersion techniques

    SciTech Connect

    Curtis, C.W. ); Gutterman, C. ); Chander, S. )

    1992-08-26

    Research in this project centers upon developing a new approach to the direct liquefaction of coal to produce an all-distillate product slate at a sizable cost reduction over current technology. The approach integrates all aspects of the coal liquefaction process including coal selection, pretreatment, coal swelling with catalyst impregnation, coal liquefaction experimentation, product recovery with characterization, alternate bottoms processing, and a technical assessment including an economic evaluation. The project is being carried out under contract to the United States Department of Energy. On May 28, 1992, the Department of Energy authorized starting the experimental aspects of this projects; therefore, experimentation at Amoco started late in this quarterly report period. Research contracts with Auburn University, Pennsylvania State University, and Foster Wheeler Development Corporation were signed during June, 1992, so their work was just getting underway. Their work will be summarized in future quarterly reports. A set of coal samples were sent to Hazen Research for beneficiation. The samples were received and have been analyzed. The literature search covering coal swelling has been up-dated, and preliminary coal swelling experiments were carried out. Further swelling experimentation is underway. An up-date of the literature on the liquefaction of coal using dispersed catalysts is nearing completion; it will be included in the next quarterly report.

  19. Case of a non-pulsatile groin swelling.

    PubMed

    Razif, M A Mohamed; Rajasingam, V; Abdullah, B J J

    2002-12-01

    We report a case of a non-pulsatile groin swelling in a 38 years old male drug addict without the typical clinical signs of an aneurysm. Ultrasound revealed a left femoral artery pseudo-aneurysm. He was surgically treated and the vessels were ligated without revascularisation.

  20. COAL CLEANING VIA LIQUID-FLUIDIZED CLASSIFICAITON (LFBC) WITH SELECTIVE SOLVENT SWELLING

    SciTech Connect

    J. M. Calo

    2000-12-01

    The concept of coal beneficiation due to particle segregation in water-fluidized beds, and its improvement via selective solvent-swelling of organic material-rich coal particles, was investigated in this study. Particle size distributions and their behavior were determined using image analysis techniques, and beneficiation effects were explored via measurements of the ash content of segregated particle samples collected from different height locations in a 5 cm diameter liquid-fluidized bed column (LFBC). Both acetone and phenol were found to be effective swelling agents for both Kentucky No.9 and Illinois No.6 coals, considerably increasing mean particle diameters, and shifting particle size distributions to larger sizes. Acetone was a somewhat more effective swelling solvent than phenol. The use of phenol was investigated, however, to demonstrate that low cost, waste solvents can be effective as well. For unswollen coal particles, the trend of increasing particle size from top to bottom in the LFBC was observed in all cases. Since the organic matter in the coal tends to concentrate in the smaller particles, the larger particles are typically denser. Consequently, the LFBC naturally tends to separate coal particles according to mineral matter content, both due to density and size. The data for small (40-100 {micro}m), solvent-swollen particles clearly showed improved beneficiation with respect to segregation in the water-fluidized bed than was achieved with the corresponding unswollen particles. This size range is quite similar to that used in pulverized coal combustion. The original process concept was amply demonstrated in this project. Additional work remains to be done, however, in order to develop this concept into a full-scale process.

  1. A rapid, non-invasive and non-destructive method for studying swelling behavior and microstructure variations of hydrogels.

    PubMed

    Li, Yaqiong; Li, Xiunan; Chen, Chao; Zhao, Dawei; Su, Zhiguo; Ma, Guanghui; Yu, Rong

    2016-10-20

    A new method for studying swelling behavior of hydrogels was developed based on low field NMR (LF-NMR). This method is established on these facts: firstly, internal water (water trapped in hydrogel) and external water (water outside of hydrogel) correspond to different components of transverse relaxation time (T2); secondly, T2 component amplitude is proportional to relative water content; and finally, T2 value is closely related to mesh size of hydrogel network, the main effect being due to the overall concentration (degree of swelling). This method was successfully applied to swelling ratio determination of chitosan/glutaraldehyde (CS/GA) hydrogels in situ, and the results had better accuracy and repeatability compared with that of weighing method. Furthermore, swelling kinetics at different pH and microstructure of CS/GA hydrogels was well elucidated based on T2. It is clearly showed that LF-NMR provides a powerful tool for probing processes related to water transport and microstructure variation of hydrogels.

  2. Adsorption-induced deformation of microporous materials: coal swelling induced by CO2-CH4 competitive adsorption.

    PubMed

    Brochard, Laurent; Vandamme, Matthieu; Pellenq, Roland J-M; Fen-Chong, Teddy

    2012-02-01

    Carbon dioxide injection in coal seams is known to improve the methane production of the coal seam, while ensuring a safe and long-term carbon sequestration. This improvement is due to the preferential adsorption of CO(2) in coal with respect to CH(4): an injection of CO(2) thus results in a desorption of CH(4). However, this preferential adsorption is also known to cause a differential swelling of coal, which results in a significant decrease in the reservoir permeability during the injection process. Recent studies have shown that adsorption in coal micropores (few angströms in size) is the main cause of the swelling. In this work, we focus on the competitive adsorption behavior of CO(2) and CH(4) in micropores. We perform molecular simulations of adsorption with a realistic atomistic model for coal. The competitive adsorption is studied at various temperatures and pressures representative of those in geological reservoirs. With the help of a poromechanical model, we then quantify the subsequent differential swelling induced by the computed adsorption behaviors. The differential swelling is almost insensitive to the geological temperatures and pressures considered here and is proportional to the CO(2) mole fraction in the coal. PMID:22185459

  3. A rapid, non-invasive and non-destructive method for studying swelling behavior and microstructure variations of hydrogels.

    PubMed

    Li, Yaqiong; Li, Xiunan; Chen, Chao; Zhao, Dawei; Su, Zhiguo; Ma, Guanghui; Yu, Rong

    2016-10-20

    A new method for studying swelling behavior of hydrogels was developed based on low field NMR (LF-NMR). This method is established on these facts: firstly, internal water (water trapped in hydrogel) and external water (water outside of hydrogel) correspond to different components of transverse relaxation time (T2); secondly, T2 component amplitude is proportional to relative water content; and finally, T2 value is closely related to mesh size of hydrogel network, the main effect being due to the overall concentration (degree of swelling). This method was successfully applied to swelling ratio determination of chitosan/glutaraldehyde (CS/GA) hydrogels in situ, and the results had better accuracy and repeatability compared with that of weighing method. Furthermore, swelling kinetics at different pH and microstructure of CS/GA hydrogels was well elucidated based on T2. It is clearly showed that LF-NMR provides a powerful tool for probing processes related to water transport and microstructure variation of hydrogels. PMID:27474678

  4. Swelling and drug release behavior of poly(2-hydroxyethyl methacrylate/itaconic acid) copolymeric hydrogels obtained by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Tomić, S. Lj.; Mićić, M. M.; Filipović, J. M.; Suljovrujić, E. H.

    2007-05-01

    The new copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were prepared by gamma irradiation, in order to examine the potential use of these hydrogels in controlled drug release systems. The influence of IA content in the gel on the swelling characteristics and the releasing behavior of hydrogels, and the effect of different drugs, theophylline (TPH) and fenethylline hydrochloride (FE), on the releasing behavior of P(HEMA/IA) matrix were investigated in vitro. The diffusion exponents for swelling and drug release indicate that the mechanisms of buffer uptake and drug release are governed by Fickian diffusion. The swelling kinetics and, therefore, the release rate depends on the matrix swelling degree. The drug release was faster for copolymeric hydrogels with a higher content of itaconic acid. Furthermore, the drug release for TPH as model drug was faster due to a smaller molecular size and a weaker interaction of the TPH molecules with(in) the P(HEMA/IA) copolymeric networks.

  5. Malonate induces cell death via mitochondrial potential collapse and delayed swelling through an ROS-dependent pathway

    PubMed Central

    Fernandez-Gomez, Francisco J; Galindo, Maria F; Gómez-Lázaro, Maria; Yuste, Victor J; Comella, Joan X; Aguirre, Norberto; Jordán, Joaquín

    2005-01-01

    Herein we study the effects of the mitochondrial complex II inhibitor malonate on its primary target, the mitochondrion. Malonate induces mitochondrial potential collapse, mitochondrial swelling, cytochrome c (Cyt c) release and depletes glutathione (GSH) and nicotinamide adenine dinucleotide coenzyme (NAD(P)H) stores in brain-isolated mitochondria. Although, mitochondrial potential collapse was almost immediate after malonate addition, mitochondrial swelling was not evident before 15 min of drug presence. This latter effect was blocked by cyclosporin A (CSA), Ruthenium Red (RR), magnesium, catalase, GSH and vitamin E. Malonate added to SH-SY5Y cell cultures produced a marked loss of cell viability together with the release of Cyt c and depletion of GSH and NAD(P)H concentrations. All these effects were not apparent in SH-SY5Y cells overexpressing Bcl-xL. When GSH concentrations were lowered with buthionine sulphoximine, cytoprotection afforded by Bcl-xL overexpression was not evident anymore. Taken together, all these data suggest that malonate causes a rapid mitochondrial potential collapse and reactive oxygen species production that overwhelms mitochondrial antioxidant capacity and leads to mitochondrial swelling. Further permeability transition pore opening and the subsequent release of proapoptotic factors such as Cyt c could therefore be, at least in part, responsible for malonate-induced toxicity. PMID:15655518

  6. Swelling and mechanical properties of physically crosslinked poly(vinyl alcohol) hydrogels.

    PubMed

    Suzuki, Atsushi; Sasaki, Saori

    2015-12-01

    Physically crosslinked poly(vinyl alcohol) gels are versatile biomaterials due to their excellent biocompatibility. In the past decades, physically crosslinked poly(vinyl alcohol) and poly(vinyl alcohol)-based hydrogels have been extensively studied for biomedical applications. However, these materials have not yet been implemented due to their mechanical strength. Physically crosslinked poly(vinyl alcohol) gels consist of a swollen amorphous network of poly(vinyl alcohol) physically crosslinked by microcrystallites. Although the mechanical properties can be improved to some extent by controlling the distribution of microcrystallites on the nano- and micro-scales, enhancing the mechanical properties while maintaining high water content remains very difficult. It may be technologically impossible to significantly improve the mechanical properties while keeping the gel's high water absorbance ability using conventional fabrication methods. Physical and chemical understandings of the swelling and mechanical properties of physically crosslinked poly(vinyl alcohol) gels are considered here; some promising strategies for their practical applications are presented. This review focuses more on the recent studies on swelling and mechanical properties of poly(vinyl alcohol) hydrogels, prepared using only poly(vinyl alcohol) and pure water with no other chemicals, as potential biomedical materials. PMID:26614797

  7. Influence of binary swelling solvents: Mechanism of action

    SciTech Connect

    Ding, R.; Tucker, D.; Kispert, L.D.

    1995-12-31

    This study addresses the dramatic up-take of a poor swelling solvent in Argonne Premium Coal Samples (APCS), Illinois No. 6, Beulah-Zap and Lewiston-Stockton when such a solvent is spiked with various amounts of the strong swelling solvent, pyridine. The unexpected up-take can be explained in terms of four different processes: (1) disruption of weak hydrogen bonds which isolate the interconnected micropore system; (2) disruption of weak hydrogen bonds which protect individual micropores; (3) competition of pyridine for the active sites involved in the hydrogen bonds or the {open_quotes}poisoning{close_quotes} of active sites; and (4) disruption of stronger hydrogen bonds within the macromolecules which causes an opening of the structure. When more than 5% pyridine is used, no additional disruption of the hydrogen-bonded network occurs. The structural changes were monitored by spin probe incorporation which was measured by EPR spectroscopy.

  8. Swell activated chloride channel function in human neutrophils

    SciTech Connect

    Salmon, Michael D.; Ahluwalia, Jatinder

    2009-04-17

    Non-excitable cells such as neutrophil granulocytes are the archetypal inflammatory immune cell involved in critical functions of the innate immune system. The electron current generated (I{sub e}) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential. For continuous function of the NADPH oxidase, I{sub e} has to be balanced to preserve electroneutrality, if not; sufficient depolarisation would prevent electrons from leaving the cell and neutrophil function would be abrogated. Subsequently, the depolarisation generated by the neutrophil NADPH oxidase I{sub e} must be counteracted by ion transport. The finding that depolarisation required counter-ions to compensate electron transport was followed by the observation that chloride channels activated by swell can counteract the NADPH oxidase membrane depolarisation. In this mini review, we discuss the research findings that revealed the essential role of swell activated chloride channels in human neutrophil function.

  9. A Process to Reduce DC Ingot Butt Curl and Swell

    NASA Astrophysics Data System (ADS)

    Yu, Ho

    1980-11-01

    A simple and effective process to reduce DC ingot butt curl and swell has been developed in the Ingot Casting Division of Alcoa Technical Center.1 In the process, carbon dioxide gas is dissolved under high pressure into the ingot cooling water upstream of the mold during the first several inches of the ingot cast. As the cooling water exits from the mold, the dissolved gas evolves as micron-size bubbles, forming a temporary effective insulation layer on the ingot surface. This reduces thermal stress in the ingot butt. An insulation pad covering about 60% of the bottom block is used in conjunction with the carbon dioxide injection when maximum butt swell reduction is desired. The process, implemented in four Alcoa ingot plants, has proven extremely successful.

  10. Reactivity, swelling and aggregation of mixed-size silicate nanoplatelets.

    PubMed

    Segad, M; Cabane, B; Jönsson, Bo

    2015-10-21

    Montmorillonite is a key ingredient in a number of technical applications. However, little is known regarding the microstructure and the forces between silicate platelets. The size of montmorillonite platelets from different natural sources can vary significantly. This has an influence on their swelling behavior in water as well as in salt solutions, particularly when tactoid formation occurs, that is when divalent counterions are present in the system. A tactoid consists of a limited number of platelets aggregated in a parallel arrangement with a constant separation. The tactoid size increases with platelet size and with very small nanoplatelets, ∼30 nm, no tactoids are observed irrespectively of the platelet origin and concentration of divalent ions. The formation and dissociation of tactoids seem to be reversible processes. A large proportion of small nanoplatelets in a mixed-size system affects the tactoid formation, reduces the aggregation number and increases the extra-lamellar swelling in the system. PMID:26376952

  11. Osteoma Presenting as a Painless Solitary Mastoid Swelling

    PubMed Central

    Abdel Tawab, Hazem M.; Kumar V, Ravi; Tabook, Salim M. Sloma

    2015-01-01

    Introduction. Osteoma of the temporal bone is a very uncommon benign tumor of bone. Osteomas may occur in the external auditory canals but are reported to be very rare in the mastoid bone. Case Report. A 36-year-old male presented to our department with a hard swelling behind the right ear diagnosed as osteoma. Complete excision was done through a postauricular approach. Histopathology confirmed the diagnosis of osteoma. Conclusion. Osteomas, although rare, should be considered when dealing with any hard mastoid swelling. Complete removal can be ensured by drilling till the normal cortical bone is reached to avoid recurrence. A cortical mastoidectomy should be done if the mastoid air cell system is involved. PMID:25767729

  12. Swelling of vallate papillae of the tongue following arsenic exposure.

    PubMed

    Sarwar, A F M; Ahmad, S Akhtar; Khan, Manzurul Haque; Sayed, M H Salim Ullah; Kabir, M Humayun

    2010-04-01

    This cross-sectional study was carried out in some selected arsenic contaminated rural areas of Bangladesh to determine any clinical changes in oral cavity, among the arsenic exposed population through drinking water. Total 600 respondents (200 arsenicosis patients, 200 non-patients but having the history of taking arsenic contaminated water and another 200 arsenic non-exposed). 75.5% of arsenicosis patients had swelled vallate papillae whereas only 44.5% and 8.5% in case of arsenic exposure and non-exposure subjects respectively. The differences were found statistically significant (p < 0.001). This study suggests that there is a tendency of developing swelled vallate papillae among the arsenic exposed population.

  13. Hybrid composites prepared from Industrial waste: Mechanical and swelling behavior

    PubMed Central

    Ahmed, Khalil

    2013-01-01

    In this assessment, hybrid composites were prepared from the combination of industrial waste, as marble waste powder (MWP) with conventional fillers, carbon black (CB) as well as silica as reinforcing material, incorporated with natural rubber (NR). The properties studied were curing, mechanical and swelling behavior. Assimilation of CB as well as silica into MWP containing NR compound responded in decreasing the scorch time and cure time besides increasing in the torque. Additionally, increasing the CB and silica in their respective NR hybrid composite increases the tensile, tear, modulus, hardness, and cross-link density, but decreases the elongation and swelling coefficient. The degradation property e.g., thermal aging of the hybrid composite was also estimated. The overall behavior at 70 °C aging temperature signified that the replacement of MS by CB and silica improved the aging performance. PMID:25750756

  14. Simulation of extrudate swell using an extended finite element method

    NASA Astrophysics Data System (ADS)

    Choi, Young Joon; Hulsen, Martien A.

    2011-09-01

    An extended finite element method (XFEM) is presented for the simulation of extrudate swell. A temporary arbitrary Lagrangian-Eulerian (ALE) scheme is incorporated to cope with the movement of the free surface. The main advantage of the proposed method is that the movement of the free surface can be simulated on a fixed Eulerian mesh without any need of re-meshing. The swell ratio of an upper-convected Maxwell fluid is compared with those of the moving boundary-fitted mesh problems of the conventional ALE technique, and those of Crochet & Keunings (1980). The proposed XFEM combined with the temporary ALE scheme can provide similar accuracy to the boundary-fitted mesh problems for low Deborah numbers. For high Deborah numbers, the method seems to be more stable for the extrusion problem.

  15. Reactivity, swelling and aggregation of mixed-size silicate nanoplatelets

    NASA Astrophysics Data System (ADS)

    Segad, M.; Cabane, B.; Jönsson, Bo

    2015-10-01

    Montmorillonite is a key ingredient in a number of technical applications. However, little is known regarding the microstructure and the forces between silicate platelets. The size of montmorillonite platelets from different natural sources can vary significantly. This has an influence on their swelling behavior in water as well as in salt solutions, particularly when tactoid formation occurs, that is when divalent counterions are present in the system. A tactoid consists of a limited number of platelets aggregated in a parallel arrangement with a constant separation. The tactoid size increases with platelet size and with very small nanoplatelets, ~30 nm, no tactoids are observed irrespectively of the platelet origin and concentration of divalent ions. The formation and dissociation of tactoids seem to be reversible processes. A large proportion of small nanoplatelets in a mixed-size system affects the tactoid formation, reduces the aggregation number and increases the extra-lamellar swelling in the system.

  16. Modeling the rapid de-swelling of toroidal hydrogels

    NASA Astrophysics Data System (ADS)

    Nikolov, Svetoslav; Chang, Ya-Wen; Alexeev, Alexander; Fernandez de Las Nieves, Alberto

    2015-03-01

    The utilization of synthetic hydrogel networks as 3-D cell culture platforms has allowed researchers to more effectively study how epigenetic factors affect cell growth and physiology. As a whole, this has emphasized the biomechanical role of scaffold structures and led to a number of advances in tissue engineering. Our current research focuses on modeling temperature activated shape transformations of toroidal poly(N-isopropylacrylamide) pNIPAM gels. We use dissipative particle dynamics (DPD) to simulate the steady (slow heating rates) and unsteady (fast heating rates) de-swelling behavior of these thermo-sensitive gels. Our simulations show that for slow heating rates the aspect ratio of the tori remains constant during de-swelling. For rapid heating rates we observe buckling instabilities. Our simulations agree with the experimental observations. Financial support by NSF CAREER Award DMR-1255288 is gratefully acknowledged.

  17. Ion implantation induced swelling in 6H-SiC

    SciTech Connect

    Nipoti, R.; Albertazzi, E.; Bianconi, M.; Lotti, R.; Lulli, G.; Cervera, M.; Carnera, A.

    1997-06-01

    Ion implantation induced surface expansion (swelling) of 6H-SiC was investigated through the measurement of the step height between implanted and unimplanted areas. The samples were irradiated at room temperature with 500 keV Al{sup +} ions in the dose range 1.25{times}10{sup 14}{endash}3{times}10{sup 15}ionscm{sup {minus}2}. Swelling was related to dose and the area density of ion-induced damage measured by Rutherford backscattering channeling technique. The observed trend is consistent with the hypothesis that the volume expansion of the ion damaged crystal is proportional to the area density of displaced atoms, plus an additional relaxation occurring at the onset of the crystalline to amorphous transition. {copyright} {ital 1997 American Institute of Physics.}

  18. Modeling imbibition of liquids into rigid and swelling porous media

    NASA Astrophysics Data System (ADS)

    Masoodi, Reza

    hydrodynamic pressure as well as the capillary suction-pressure are the drivers, was studied experimentally and modeled analytically. Both the Darcy's-law based approach as well as the Washburn-equation based approach were used as models. The former was shown to work better at zero or low external pressures, while the latter displayed good predictive capabilities at higher imposed pressures. We also studied flow in non-rigid swelling porous media. The continuity equation was modified to include the liquid-absorption and swelling effects, and then Darcy's law was employed to model wicking in paper stripes made from cellulose and superabsorbent polymers. The proposed model showed very good agreement with previous experimental results. It was shown that the wicking predictions by the newly proposed model are identical to the predictions of another theoretical model in which Washburn equation was modified to include the swelling effects. The wicking in swelling paper stripes was also modeled numerically using PORE-FLOW(c). Once again the continuity equation, modified to include the liquid-absorption and swelling effects, coupled with the Darcy's law formed the governing equations. The porosity and hence permeability in a swelling medium are a function of time in such a situation. A new method was proposed to estimate the local permeability in such swelling media from the absorbed-mass-vs-time plot to enable the numerical simulation of such a wicking process. The numerical results compared well with the experimental data and it proved the effectiveness of our suggested local-permeability estimation method as well as our wicking model for the swelling media.

  19. Myoparasitism mimicking parotid swelling: a rare presentation of cysticercosis

    PubMed Central

    Tewari, Sandeep; Singh, Saumya; Jaiswal, Vaibhav; Mishra, Anand Kumar

    2014-01-01

    Muscular infestation with larval stage of Taenia solium is a well-recognised entity but cysticercosis of the head and neck region is a rarity. We present a case of 35-year-old young man with diffuse swelling of 3.5×4 cm in the parotid region on the right side of the face with signs of inflammation. Diagnosis was established on high-resolution ultrasonography which revealed it to be of parasitic origin. The patient was managed with antihelminthic pharmacotherapy and improved within a month. Thus cysticercosis should be considered in the differential diagnosis of subcutaneous swellings of the head and neck region, especially in endemic zones and it must be investigated well with appropriate imaging modalities so that inadvertent surgery can be avoided. PMID:24842360

  20. Neck swelling after thyroidectomy: not always a haematoma.

    PubMed

    Zou, Maggie; Reid, Diane; Ravichandran, Duraisamy

    2015-01-01

    We present a case of a patient who returned with a neck swelling 6 days following thyroidectomy and central neck compartment lymphadenectomy for suspected thyroid carcinoma. The initial clinical suspicion pointed to a haematoma, but a needle aspiration showed chyle. Chyle leak is a rare complication of thyroid surgery. In the described case, this was successfully managed conservatively with repeated aspirations and a low-fat diet. We discuss the aetiology, presentation and management of this complication. PMID:26564112

  1. Swelling behaviors of porous lignin based poly (acrylic acid).

    PubMed

    Ma, Yanli; Sun, Yajie; Fu, Yujie; Fang, Guizhen; Yan, Xingru; Guo, Zhanhu

    2016-11-01

    Supramolecular cross-linked porous lignin based poly (acrylic acid) [LBPAA] was lab-synthesized by copolymerizing lignin grafted N, N'-methylene-bisacrylamide (LM) and acrylic acid. LBPAA successfully acted as a water retention agent with salt resistance and biodegradation for agricultural applications. Lignin was found to improve its swelling behaviors with higher water retention, fast swelling and de-swelling rates. The salt tolerance was stronger in the case of LBPAA (60 PAA/40 LM) [60 wt% PAA/40 wt% LM], i.e., 145.79 g·g(-1) higher than PAA at 0.09 mM KCl solution. The effect of ion charges on the LBPAA swelling ratio was greater than that of ionic radius. The weight loss of LBPAA (60 PAA/40 LM) was 5.47%, 4.96%, and 4.56% in the soil of Tangshan, Harbin, and Sian, respectively. The soil moisture content and clay content were observed to decrease gradually with increasing the burial time. The biodegradation test of LBPAA (60 PAA/40 LM) composite exhibited different bacterial colony forming units (CFU), the soil of Tangshan was 2.0 × 10(3) CFU·g(-1) soil, 7.0 × 10(3) CFU·g(-1) soil for Harbin, and 6.10 × 10(4) CFU·g(-1) soil for Sian. However, the organic matter contents in the soils did not have significant changes (Tangshan 6.21 mg·g(-1), Harbin 0.61 mg·g(-1), and Sian 0.405 mg·g(-1)). PMID:27587327

  2. Magnetic relaxation - coal swelling, extraction, pore size. Final technical report

    SciTech Connect

    Doetschman, D.C.

    1994-10-26

    The aim of the contract was to employ electron and nuclear magnetic relaxation techniques to investigate solvent swelling of coals, solvent extraction of coals and molecular interaction with solvent coal pores. Many of these investigations have appeared in four major publications and a conference proceedings. Another manuscript has been submitted for publication. The set of Argonne Premium Coals was chosen as extensively characterized and representative samples for this project.

  3. SuperLig Ion Exchange Resin Swelling and Buoyancy Study

    SciTech Connect

    Hassan, N.M.

    2000-07-27

    The objective of this study was to achieve a fundamental understanding of SuperLig resin swelling and shrinking characteristics, which lead to channeling and early breakthrough during loading cycles. The density of salt solution that causes resin floating was also determined to establish a limit for operation. Specific tests performed include (a) pH dependence, (b) ionic strength dependence and (c) buoyancy effect vs. simulant composition.

  4. Xanthogranulomatous Osteomyelitis Presenting as Swelling in Right Tibia

    PubMed Central

    Kamat, Girish; Gramapurohit, Vandana; Myageri, Aneel; Shettar, Chidendra

    2011-01-01

    Xanthogranulomatous osteomyelitis is a very rare form of chronic osteomyelitis which presents like a bone tumor. Three cases of xanthogranulomatous osteomyelitis have been described previously in the literature. We present a case of xanthogranulomatous osteomyelitis occurring in the distal part of tibia. This case presented as swelling in a 13-year-old boy. Simple curettage proved to be curative in the present case. PMID:22937381

  5. Asymptomatic, nonulcerated swelling of the posterior hard palate.

    PubMed

    Correll, R W; Wescott, W B; Pierce, G L

    1982-09-01

    It is very important for clinicians to understand that nonulcerated, firm, dome-shaped, nonpainful palatal swellings, if not inflammatory in nature, are probably arising in the palatal accessory salivary glands. The differential diagnosis must include benign mixed tumors; adenoid cystic carcinoma, and necrotizing sialometaplasia, which is usually ulcerated. Statistically, the possibility that the lesion is malignant is slightly greater than the possibility that it is benign. Incisional biopsy must be performed on these lesions to determine the proper treatment and management regimen.

  6. Acute parotitis and hyperamylasemia following whole-brain radiation therapy

    SciTech Connect

    Cairncross, J.G.; Salmon, J.; Kim, J.H.; Posner, J.B.

    1980-04-01

    Parotitis, an infrequent, previously unreported complication of whole-brain radiation therapy, was observed in 4 patients. The acute symptoms, which include fever, dry mouth, pain, swelling, and tenderness, are accompanied by hyperamylasemia. Among 10 patients receiving whole-brain irradiation, 8 had serum amylase elevations without symptoms. Both acute parotitis and asymptomatic hyperamylasemia result from irradiation of the parotid glands.

  7. Molecular accessibility in solvent swelled coals. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1993-02-01

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a non swelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration is measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method had also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data show that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 mn). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of the EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of coal, thus providing information on the importance of molecular shape.

  8. Influence of different alcohols on the swelling behaviour of hydrogels

    NASA Astrophysics Data System (ADS)

    Althans, Daniel; Langenbach, Kai; Enders, Sabine

    2012-06-01

    The swelling equilibrium of cross-linked poly(N-isopropylacrylamide) (PNIPAAm) hydrogels in alcohol solutions as a function of temperature, alcohol concentration, kind of alcohol (C1OH-C3OH) and gel properties was investigated experimentally. Additionally, the swelling degree as a function of the alcohol concentration was modelled with the UNIQUAC-Free Volume model in combination with the Phantom Network theory. The experiments show that, in pure water, the transition temperature is between 303.15 and 308.15 K depending on the properties of the gel and hence on the polymerization conditions. The transition from a swollen to a shrunken state is caused by the polymeric network and the change of polymer chain localization. In a system with hydrogel + water + alcohol, the swelling degree decreases with increasing alcohol concentration until the shrunken state is reached and increases again by further addition of alcohol at constant temperature. With increasing carbon number of the alcohols, the transition from a swollen to a shrunken state and vice versa shifts to lower concentrations at constant temperature. The use of the UNIQUAC-Free Volume model with Phantom Network theory leads to results in good agreement with the experimental data.

  9. Theoretical and numerical studies of die swell flow

    NASA Astrophysics Data System (ADS)

    Al-Muslimawi, Alaa H.

    2016-08-01

    This paper focuses on the theoretical and numerical predictions of die-swell flow for viscoelastic and viscoelastoplastic fluids. The theoretical results on die swell have been obtained by Tanner for a wide class of constitutive equations, including Phan-Thien Tanner (PTT), pom-pom, and general network type models. These results are compared with numerical solutions across swelling ratio, pressure drop, state of stress, and dissipation-rate for two fluid models, exponential Phan-Thien Tanner (EPTT) and Papanastasiou-Exponential Phan-Thien Tanner (Pap-EPTT). Numerically, the momentum and continuity flow equations are solved by a semi-implicit time-stepping Taylor-Galerkin/pressure-correction finite element method, whilst the constitutive equation is dealt with by a cell-vertex finite volume ( cv/fv) algorithm. This hybrid scheme is performed in a coupled fashion on the nonlinear differential equation system using discrete subcell technology on a triangular tessellation. The hyperbolic aspects of the constitutive equation are addressed discretely through upwind fluctuation distribution techniques.

  10. Dynamic mechanical and swelling properties of maleated hyaluronic acid hydrogels.

    PubMed

    Lin, Hai; Liu, Jun; Zhang, Kai; Fan, Yujiang; Zhang, Xingdong

    2015-06-01

    A series of maleated hyaluronan (MaHA) are developed by modification with maleic anhydride. The degrees of substitution (DS) of MaHA vary between 7% and 75%. The DS of MaHA is both higher and wider than methacrylated HA derivatives (MeHA) reported in the literature. MaHA hydrogels are then prepared by photopolymerization and their dynamic mechanical and swelling properties of the hydrogels are investigated. The results showed that MaHA hydrogels with moderate DS (25%, 50% and 65%) have higher storage modulus and lower equilibrium swelling ratios than those with either low or high DS (7%, 15% and 75%). Theoretical analyses also suggest a similar pattern among hydrogels with different DS. The results confirm that the increased cross-linking density enhances the strength of hydrogels. Meanwhile, the hydrophilicity of introduced groups during modification and the degree of incomplete crosslinking reaction might have negative impact on the mechanical and swelling properties of MaHA hydrogels.

  11. Adrenergic activation attenuates astrocyte swelling induced by hypotonicity and neurotrauma.

    PubMed

    Vardjan, Nina; Horvat, Anemari; Anderson, Jamie E; Yu, Dou; Croom, Deborah; Zeng, Xiang; Lužnik, Zala; Kreft, Marko; Teng, Yang D; Kirov, Sergei A; Zorec, Robert

    2016-06-01

    Edema in the central nervous system can rapidly result in life-threatening complications. Vasogenic edema is clinically manageable, but there is no established medical treatment for cytotoxic edema, which affects astrocytes and is a primary trigger of acute post-traumatic neuronal death. To test the hypothesis that adrenergic receptor agonists, including the stress stimulus epinephrine protects neural parenchyma from damage, we characterized its effects on hypotonicity-induced cellular edema in cortical astrocytes by in vivo and in vitro imaging. After epinephrine administration, hypotonicity-induced swelling of astrocytes was markedly reduced and cytosolic 3'-5'-cyclic adenosine monophosphate (cAMP) was increased, as shown by a fluorescence resonance energy transfer nanosensor. Although, the kinetics of epinephrine-induced cAMP signaling was slowed in primary cortical astrocytes exposed to hypotonicity, the swelling reduction by epinephrine was associated with an attenuated hypotonicity-induced cytosolic Ca(2+) excitability, which may be the key to prevent astrocyte swelling. Furthermore, in a rat model of spinal cord injury, epinephrine applied locally markedly reduced neural edema around the contusion epicenter. These findings reveal new targets for the treatment of cellular edema in the central nervous system. PMID:27018061

  12. Stress-enhanced swelling of metal during irradiation

    SciTech Connect

    Garner, F.A.; Gilbert, E.R.; Porter, D.L.

    1980-04-01

    Data are available which show that stress plays a major role in the development of radiation-induced void growth in AISI 316 and many other alloys. Earlier experiments came to the opposite conclusion and are shown to have investigated stress levels which inadvertantly cold-worked the material. Stress-affected swelling spans the entire temperature range in fast reactor irradiations and accelerates with increasing irradiatin temperature. It also appears to operate in all alloy starting conditions investigated. Two major microstructural mechanisms appear to be causing the enhancement of swelling, which for tensile stresses is manifested primarily as a decrease in the incubation period. These mechanisms are stress-induced changes in the interstitial capture efficiency of voids and stress-induced changes in the vacancy emission rate of various microstructural components. There also appears to be an enhancement of intermetallic phase formation with applied stress and this is shown to increase swelling by accelerating the microchemical evolution that precedes void growth at high temperature. This latter consideration complicates the extrapolation of these data to compressive stress states.

  13. Impurities effect on the swelling of neutron irradiated beryllium

    SciTech Connect

    Donne, M.D.; Scaffidi-Argentina, F.

    1995-09-01

    An important factor controlling the swelling behaviour of fast neutron irradiated beryllium is the impurity content which can strongly affect both the surface tension and the creep strength of this material. Being the volume swelling of the old beryllium (early sixties) systematically higher than that of the more modem one (end of the seventies), a sensitivity analysis with the aid of the computer code ANFIBE (ANalysis of Fusion Irradiated BEryllium) to investigate the effect of these material properties on the swelling behaviour of neutron irradiated beryllium has been performed. Two sets of experimental data have been selected: the first one named Western refers to quite recently produced Western beryllium, whilst the second one, named Russian refers to relatively old (early sixties) Russian beryllium containing a higher impurity rate than the Western one. The results obtained with the ANFIBE Code were assessed by comparison with experimental data and the used material properties were compared with the data available in the literature. Good agreement between calculated and measured values has been found.

  14. Swelling equilibria for cationic 2-hydroxyethyl methacrylate (HEMA)-based hydrogels

    SciTech Connect

    Baker, J.P.; Blanch, H.W.; Prausnitz, J.M.

    1993-08-01

    Cationic HEMA-based hydrogels were synthesized by copolymerizing HEMA with [(methacrylamido)propyl]trimethylammonium chloride (MAPTAC). Swelling equilibria were measured in pure water an in aqueous sodium chloride solutions. Hydrogel swelling is an increasing function of the MAPTAC content. A Flory-type swelling model using a concentration-dependent Flory {Chi} parameter semi-qualitatively describes poly(HEMA co-MAPTAC) hydrogel swelling in aqueous sodium chloride.

  15. Three-Dimensional Integration of Graphene via Swelling, Shrinking, and Adaptation.

    PubMed

    Choi, Jonghyun; Kim, Hoe Joon; Wang, Michael Cai; Leem, Juyoung; King, William P; Nam, SungWoo

    2015-07-01

    The transfer of graphene from its growth substrate to a target substrate has been widely investigated for its decisive role in subsequent device integration and performance. Thus far, various reported methods of graphene transfer have been mostly limited to planar or curvilinear surfaces due to the challenges associated with fractures from local stress during transfer onto three-dimensional (3D) microstructured surfaces. Here, we report a robust approach to integrate graphene onto 3D microstructured surfaces while maintaining the structural integrity of graphene, where the out-of-plane dimensions of the 3D features vary from 3.5 to 50 μm. We utilized three sequential steps: (1) substrate swelling, (2) shrinking, and (3) adaptation, in order to achieve damage-free, large area integration of graphene on 3D microstructures. Detailed scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and electrical resistance measurement studies show that the amount of substrate swelling as well as the flexural rigidities of the transfer film affect the integration yield and quality of the integrated graphene. We also demonstrate the versatility of our approach by extension to a variety of 3D microstructured geometries. Lastly, we show the integration of hybrid structures of graphene decorated with gold nanoparticles onto 3D microstructure substrates, demonstrating the compatibility of our integration method with other hybrid nanomaterials. We believe that the versatile, damage-free integration method based on swelling, shrinking, and adaptation will pave the way for 3D integration of two-dimensional (2D) materials and expand potential applications of graphene and 2D materials in the future.

  16. Inversion and assessment of swell waveheights from HF radar spectra in the Iroise Sea

    NASA Astrophysics Data System (ADS)

    Wang, Weili; Forget, Philippe; Guan, Changlong

    2016-04-01

    As an extension of previous work in Wang et al. (Ocean Dyn 64:1447-1456, 2014), this article presents significant waveheights of swell inverted from a 13 month dataset of two high-frequency (HF) phased array radars. As an important intermediate variable in the calculation of significant waveheights, relative swell directions obtained by two different methods from a single radar station are also presented. The impact of the inaccuracy of relative swell direction on the calculation of waveheight is investigated and an alternative way of using constant swell direction is proposed. Radar-inverted swell significant waveheights using different ranges of relative swell directions are investigated. Results are assessed by WAVEWATCH III model hind casts. Analysis of the complete database shows that radar-inverted swell significant waveheights agree reasonably well with model estimates with large scatter. Standard deviation of the difference between the two estimations increases with waveheight, whereas the relative standard deviation, normalized by waveheight, keeps nearly constant. The constant direction scheme of waveheight inversion gives good estimations except for energetic swell exceeding the small perturbation assumption. Statistical analysis suggests that radar measurement uncertainty explains a considerable part of the difference between radar and model estimates. Swell estimates from both radar stations are consistent. This enables combined use of both radar spectra at common radar cells. Use of double spectra solves the ambiguity of relative swell direction, i.e., absolute swell direction is obtained, and effectively improves the accuracy of swell direction by the least-squares method.

  17. Kinetic characterization of swelling of liquid crystalline phases of glyceryl monooleate.

    PubMed

    Lee, Jaehwi; Choi, Sung-Up; Yoon, Mi-Kyeong; Choi, Young Wook

    2003-10-01

    Research in this paper focuses on the kinetic evaluation of swelling of the liquid crystalline phases of glyceryl monooleate (GMO). Swelling of the lamellar and cubic liquid crystalline phases of GMO was studied using two in vitro methods, a total immersion method and a Franz cell method. The swelling of the lamellar phase and GMO having 0 %w/w initial water content was temperature dependent. The swelling ratio was greater at 20 degrees C than 37 degrees C. The water uptake increased dramatically with decreasing initial water content of the liquid crystalline phases. The swelling rates obtained using the Franz cell method with a moist nylon membrane to mimic buccal drug delivery situation were slower than the total immersion method. The swelling was studied by employing first-order and second-order swelling kinetics. The swelling of the liquid crystalline phases of GMO could be described by second-order swelling kinetics. The initial stage of the swelling (t < 4 h) followed the square root of time relationship, indicating that this model is also suitable for describing the water uptake by the liquid crystalline matrices. These results obtained from the current study demonstrate that the swelling strongly depends on temperature, the initial water content of the liquid crystalline phases and the methodology employed for measuring the swelling of GMO.

  18. Attenuation of Acute Phase Injury in Rat Intracranial Hemorrhage by Cerebrolysin that Inhibits Brain Edema and Inflammatory Response.

    PubMed

    Yang, Yang; Zhang, Yan; Wang, Zhaotao; Wang, Shanshan; Gao, Mou; Xu, Ruxiang; Liang, Chunyang; Zhang, Hongtian

    2016-04-01

    The outcome of intracerebral hemorrhage (ICH) is mainly determined by the volume of the hemorrhage core and the secondary brain damage to penumbral tissues due to brain swelling, microcirculation disturbance and inflammation. The present study aims to investigate the protective effects of cerebrolysin on brain edema and inhibition of the inflammation response surrounding the hematoma core in the acute stage after ICH. The ICH model was induced by administration of type VII bacterial collagenase into the stratum of adult rats, which were then randomly divided into three groups: ICH + saline; ICH + Cerebrolysin (5 ml/kg) and sham. Cerebrolysin or saline was administered intraperitoneally 1 h post surgery. Neurological scores, extent of brain edema content and Evans blue dye extravasation were recorded. The levels of pro-inflammatory factors (IL-1β, TNF-α and IL-6) were assayed by Real-time PCR and Elisa kits. Aquaporin-4 (AQP4) and tight junction proteins (TJPs; claudin-5, occludin and zonula occluden-1) expression were measured at multiple time points. The morphological and intercellular changes were characterized by Electron microscopy. It is found that cerebrolysin (5 ml/kg) improved the neurological behavior and reduced the ipsilateral brain water content and Evans blue dye extravasation. After cerebrolysin treated, the levels of pro-inflammatory factors and AQP4 in the peri-hematomal areas were markedly reduced and were accompanied with higher expression of TJPs. Electron microscopy showed the astrocytic swelling and concentrated chromatin in the ICH group and confirmed the cell junction changes. Thus, early cerebrolysin treatment ameliorates secondary injury after ICH and promotes behavioral performance during the acute phase by reducing brain edema, inflammatory response, and blood-brain barrier permeability.

  19. Attenuation of Acute Phase Injury in Rat Intracranial Hemorrhage by Cerebrolysin that Inhibits Brain Edema and Inflammatory Response.

    PubMed

    Yang, Yang; Zhang, Yan; Wang, Zhaotao; Wang, Shanshan; Gao, Mou; Xu, Ruxiang; Liang, Chunyang; Zhang, Hongtian

    2016-04-01

    The outcome of intracerebral hemorrhage (ICH) is mainly determined by the volume of the hemorrhage core and the secondary brain damage to penumbral tissues due to brain swelling, microcirculation disturbance and inflammation. The present study aims to investigate the protective effects of cerebrolysin on brain edema and inhibition of the inflammation response surrounding the hematoma core in the acute stage after ICH. The ICH model was induced by administration of type VII bacterial collagenase into the stratum of adult rats, which were then randomly divided into three groups: ICH + saline; ICH + Cerebrolysin (5 ml/kg) and sham. Cerebrolysin or saline was administered intraperitoneally 1 h post surgery. Neurological scores, extent of brain edema content and Evans blue dye extravasation were recorded. The levels of pro-inflammatory factors (IL-1β, TNF-α and IL-6) were assayed by Real-time PCR and Elisa kits. Aquaporin-4 (AQP4) and tight junction proteins (TJPs; claudin-5, occludin and zonula occluden-1) expression were measured at multiple time points. The morphological and intercellular changes were characterized by Electron microscopy. It is found that cerebrolysin (5 ml/kg) improved the neurological behavior and reduced the ipsilateral brain water content and Evans blue dye extravasation. After cerebrolysin treated, the levels of pro-inflammatory factors and AQP4 in the peri-hematomal areas were markedly reduced and were accompanied with higher expression of TJPs. Electron microscopy showed the astrocytic swelling and concentrated chromatin in the ICH group and confirmed the cell junction changes. Thus, early cerebrolysin treatment ameliorates secondary injury after ICH and promotes behavioral performance during the acute phase by reducing brain edema, inflammatory response, and blood-brain barrier permeability. PMID:26498936

  20. Knee pain and swelling: An atypical presentation of metastatic colon cancer to the patella

    PubMed Central

    Gasagranda, Bethany; Leeman, Kimberly; Heller, Matthew T.

    2015-01-01

    Knee pain is a common reason for a patient to seek medical evaluation. Of the many causes of knee pain, malignancy is one of the least common. When malignancy is the etiology of the pain, it is usually due to a primary tumor of the osseous structures or soft tissues of the knee joint. Metastatic disease involving the knee joint is uncommon, with few cases reported in the literature. Of these reported cases, metastatic colon cancer is exceedingly rare. However, in a patient with new onset knee pain and the proper clinical history, metastatic disease should be considered as a potential explanation of symptoms. We report a case of knee pain and swelling due to metastatic colon cancer to the patella. PMID:27141244

  1. Regional Distribution of Copper, Zinc and Iron in Brain of Wistar Rat Model for Non-Wilsonian Brain Copper Toxicosis.

    PubMed

    Pal, Amit; Prasad, Rajendra

    2016-03-01

    In previous studies, we have reported first in vivo evidence of copper deposition in the choroid plexus, cognitive impairments, astrocytes swelling (Alzheimer type II cells) and astrogliosis (increase in number of astrocytes), and degenerated neurons coupled with significant increase in the hippocampus copper and zinc content in copper-intoxicated Wistar rats. Nonetheless, hippocampus iron levels were not affected by chronic copper-intoxication. Notwithstanding information on distribution of copper, zinc and iron status in different regions of brain due to chronic copper exposure remains fragmentary. In continuation with our previous study, the aim of this study was to investigate the effects of intraperitoneally injected copper lactate (0.15 mg Cu/100 g body weight) daily for 90 days on copper, zinc and iron levels in different regions of the brain using atomic absorption spectrophotometry. Copper-intoxicated group showed significantly increased cortex, cerebellum and striatum copper content (76, 46.8 and 80.7 % increase, respectively) compared to control group. However, non-significant changes were observed for the zinc and iron content in cortex, cerebellum and striatum due to chronic copper exposure. In conclusion, the current study demonstrates that chronic copper toxicity causes differential copper buildup in cortex, cerebellum and striatum region of central nervous system of male Wistar rats; signifying the critical requirement to discretely evaluate the effect of copper neurotoxicity in different brain regions, and ensuing neuropathological and cognitive dysfunctions. PMID:26855494

  2. Linking natural microstructures with numerical modeling of pinch-and-swell structures

    NASA Astrophysics Data System (ADS)

    Peters, Max; Berger, Alfons; Herwegh, Marco; Regenauer-Lieb, Klaus

    2016-04-01

    dominated deformation at relatively high extensional strains in the pinches. The numerical simulations indicate that viscosity weakening due to dissipated heat from grain size reduction marks the onset of localization, resulting in continuous necking of the layer. Interestingly, there exist multiple steady states, i.e. a first homogeneous state out of which localization arises, steady states of the stable end-member structure, expressed by homogeneous conditions in both pinches and swells, and in the surrounding matrix, the latter obeying a linear rheology. Based on our microstructural and numerical results, we suggest that the onset of localization represents a fundamental material bifurcation. This implies that the studied structures can be described as ductile instabilities. Finally, we discuss the profound role of the energy theory of localization described here, which allows deriving the paleo-deformation conditions, as well as fundamental material properties in a self-consistent manner. REFERENCES Herwegh, M., Poulet, T., Karrech, A. and Regenauer-Lieb, K. (2014): Journal of Geophysical Research 119, doi:10.1002/2013JB010701 Peters, M., Veveakis, M., Poulet, T., Karrech, A., Herwegh, M. and Regenauer-Lieb, K. (2015): Journal of Structural Geology 78, doi:10.1016/j.jsg.2015.06.005

  3. Distinctive neck swelling in a patient with a vein of Galen arteriovenous malformation.

    PubMed

    Agarwal, Arnav; Firdouse, Mohammed; De Almeida, Claudia Lace; Mondal, Tapas

    2015-06-01

    A vein of Galen arteriovenous malformation (VGAM) is a rare intracranial shunt lacking a capillary bed and resulting in subsequent aneurysmal enlargement. VGAM has been previously reported to present as cardiovascular abnormalities, including increased right-sided cardiac load and pressure, cardiac dilatation, pulmonary hypertension and retrograde flow into the aortic arch. We report the first case of VGAM presenting as a gross right-sided neck swelling in a 39-week-old immediately at birth. Transthoracic echocardiography detected dilatation of the superior vena cava and innominate vein, increased right ventricular and pulmonary arterial pressure, and retrograde flow into the aortic arch. Follow-up neck ultrasound revealed tortuous carotid artery and bilateral dilatation of neck veins. Transcranial ultrasound revealed abnormally dilated vessels posterior to the third ventricle, confirming VGAM. Our case demonstrates that while the differential diagnoses of neck swelling are extensive, such a presentation upon Doppler and echocardiographic investigation, may be suggestive of extracardiac causes such as VGAM. The management of such a condition remains critical due to risk of hemorrhage and extensive cerebral involvement.

  4. On sorption and swelling of CO2 in clays

    DOE PAGES

    Busch, A.; Bertier, P.; Gensterblum, Y.; Rother, G.; Spiers, C. J.; Zhang, M.; Wentinck, H. M.

    2016-03-23

    One well-studied technology is the geological storage of carbon dioxide (CO2), and a number of demonstration projects around the world have proven its feasibility and challenges. Storage conformance and seal integrity are among the most important aspects, as they determine risk of leakage as well as limits for storage capacity and injectivity. By providing evidence for safe storage is critical for improving public acceptance. Most caprocks are composed of clays as dominant mineral type which can typically be illite, kaolinite, chlorite or smectite. A number of recent studies addressed the interaction between CO2 and these different clays and it wasmore » shown that clay minerals adsorb considerable quantities of CO2. For smectite this uptake can lead to volumetric expansion followed by the generation of swelling pressures. On the one hand CO2 adsorption traps CO2, on the other hand swelling pressures can potentially change local stress regimes and in unfavourable situations shear-type failure is assumed to occur. Moreover, for storage in a reservoir having high clay contents the CO2 uptake can add to storage capacity which is widely underestimated so far. Smectite-rich seals in direct contact with a dry CO2 plume at the interface to the reservoir might dehydrate leading to dehydration cracks. Such dehydration cracks can provide pathways for CO2 ingress and further accelerate dewatering and penetration of the seal by supercritical CO2. At the same time, swelling may also lead to the closure of fractures or the reduction of fracture apertures, thereby improving seal integrity. Finally, the goal of this communication is to theoretically evaluate and discuss these scenarios in greater detail in terms of phenomenological mechanisms, but also in terms of potential risks or benefits for carbon storage.« less

  5. Swelling of the vesicle is prerequisite for PTH secretion.

    PubMed

    Lim, S K; Kwon, Y H; Song, Y D; Lee, H C; Ryu, K J; Huh, K B; Park, C S

    1996-02-01

    Unlike most secretory cells, high extra cellular calcium inhibits rather than stimulates hormonal secretion in several cells such as parathyroid cells, Juxtaglomerular cells and osteoclast. To gain further insight into the common but unique stimulus-secretion coupling mechanism in these cells, bovine parathyroid slices were incubated in various conditions of Krebs-Ringer (KR) solution containing essential amino acids. Parathyroid cells showed the inverse dependency of secretion on extra cellular calcium concentration as we expected. Ammonium acetate overcame the inhibitory effect of 2.5 mM of calcium and the maximum effect was as much as the five times of the basal value, while there was a little additive effect under 0 mM CaCl2. PTH secretion was biphasic according to the change of extra cellular osmolarity and the lowest response was observed at 300 mOsm/l. In Na-rich KR solution, high concentration of nigericin (> 10(-4)M) completely overcame the inhibitory effect of 2.5 mM CaCl2 and the maximum stimulatory effect was 8 times greater whereas it was only 2 times greater without CaCl2. In K-rich KR solution that abolished the K-gradient between the extra cellular solution and the cytoplasm, the rate of PTH secretion increased, and furthermore the addition of nigericin increased the rate of secretion significantly. The results above suggested that the osmotic swelling of the secretory vesicle in parathyroid cells might promote exocytosis as in Juxtaglomerular cells. We propose that the swelling of the vesicle is also prerequisite for secretion in several cells inhibited paradoxically by Ca++, whatever the signal transduction pathway for swelling of the secretory granules induced by the lowering of Ca++ in cytoplasm are.

  6. Surface Fractal Dimension of Bentonite and its Application in Calculation of Swelling Deformation

    NASA Astrophysics Data System (ADS)

    Xiang, G. S.; Xu, Y. F.; Jiang, H.

    2014-09-01

    The correlation between the void ratio of swelled montmorillonite and the vertical overburden pressure can be expressed as {e}{ m} = Kp{ s}{D{ s}-3}. The surface fractal dimension Ds of five bentonites were estimated from the swelling deformation tests according to this fractal correlation. The reliability of surface fractal dimension obtained from the swelling deformation test was confirmed by nitrogen adsorption test, with identical values of surface fractal dimension obtained from both tests. The surface fractal dimension can also be used to estimate the swelling deformation of bentonite, after calculating the swelling coefficient K from the parameters of diffuse double layer (DDL) model in the osmotic swelling phase. Comparison of the model predictions with a number of experimental results on swelling deformation of both Na dominant and Ca dominant bentonites suggests that the surface fractal model works excellent in the cases tested.

  7. Determination of yeast mitochondrial KHE activity, osmotic swelling and mitophagy.

    PubMed

    Nowikovsky, Karin; Devenish, Rodney J; Froschauer, Elisabeth; Schweyen, Rudolf J

    2009-01-01

    The mitochondrial K(+)/H(+) exchanger (KHE) is a key regulator of mitochondrial K(+), the most abundant cellular cation, and thus for volume control of the organelle. Downregulation of the mitochondrial KHE results in osmotic swelling and autophagic degradation of the organelle. This chapter describes methods to shut-off expression of Mdm38p, an essential factor of the mitochondrial KHE, and to observe the cellular consequences thereof, in particular changes in KHE activity and morphogenetic changes of mitochondria by applying new techniques developed in our laboratories. PMID:19426875

  8. Rhinosporidiosis of lacrimal sac: An interesting case of orbital swelling

    PubMed Central

    Basu, Sandip Kanti; Bain, Jayanta; Maity, Kuntal; Chattopadhyay, Debarati; Baitalik, Debasis; Majumdar, Bijay Kumar; Gupta, Vivek; Kumar, Ashwini; Dalal, Bibhas Saha; Malik, Anu

    2016-01-01

    Rhinosporidiosis is a chronic localized granulomatous disease caused by Rhinosporidium seeberi, an aquatic protistan parasite belonging to a clade, Mesomycetozoea. Infestation of Rhinosporidiosis to the eye and adnexa is termed oculosporidiosis, in such cases, conjunctival mucosa is mostly involved; however in our case, it involved only the lacrimal sac and deeper periorbital tissue and presented as a case of orbital swelling. Surgical excision of the lesion was done, postoperatively dapsone therapy was given for 6 months, and the patient responded very well with no recurrence till date. PMID:27003980

  9. Cornea, and the swelling of polyelectrolyte gels of biological interest

    NASA Astrophysics Data System (ADS)

    Elliott, Gerald F.; Hodson, Stuart A.

    1998-10-01

    Biological polyelectrolyte gels consist of insoluble aggregates of molecules which collectively form structural fibrils and these fibrils, or their chemically bound side chains, have a net electrical charge. These gels may be visualized as negatively charged fibrils immersed in aqueous solutions which include free diffusible ions (mainly sodium, potassium and chloride). All living cells and most of the extracellular spaces of the body are polyelectrolyte gels and they strive to swell by the absorption of additional fluid because of the Donnan potentials generated by their fixed charge. We review Donnan swelling using the cornea of the eye as prime material. Donnan swelling requires knowledge of only one parameter such as: (a) the electrical potential within the gel or (b) the distribution of any mobile ion inside and outside the gel or (c) measurement of the gel pressure or (d) the fixed charge density on the fibrils, in order to calculate all the other relevant factors. We describe the conditions (which usually exist in biological tissue) when the microscopic distribution of the fixed charge density within the gel is not important to the Donnan phenomena. Fixed charge density is generated by two sources: permanent negative charges in the structural fibrils and transient mobile ion binding to the fibrils. Ion binding to large molecules is reviewed. In the case of the cornea, transient mobile ion binding is the predominant factor in generating fixed charge density under physiological conditions. An irreversible thermodynamic treatment of gel swelling shows the intrinsic instability of polyelectrolyte gels and suggests new ways of approaching a microscopic model for osmosis. In order to stabilize the two forces (osmotic potential and chemical potential) which generate the polyelectrolyte gel instability we review the types of third forces which must be present in order to stabilize biological gels. These third forces include van der Waal's force, metabolically driven

  10. A young boy with a maxillary swelling and closed rhinolalia.

    PubMed

    Thomas, Shaji; Nair, Preeti; Kumar, Anil; Hegde, Karthik; Singh, Vikram

    2011-01-01

    Non-Hodgkin's lymphoma belongs to a group of lymphoid neoplasia that is diverse in the manner of presentation, response to therapy and progress. The most common region for extranodal lymphoma is the gastrointestinal tract while for oral cavity buccal vestibule, posterior hard palate or gingiva is the common site. The maxilla is affected more commonly than the mandible. The oral picture being the sole manifestation highlights the importance of bearing this entity in the differential diagnosis of swelling in the jaws. PMID:22715226

  11. Dynamic measurement of starch granule swelling during microwave heating.

    PubMed

    Casasnovas, Johnny; Anantheswaran, Ramaswamy C

    2016-10-20

    The size of starch granules in dilute aqueous suspension was measured in-line during gelatinization in a microwave-heated, well-mixed system. The results were compared with those of a previous study conducted with conventional heating. For the starches used (common corn, waxy maize, and cross-linked waxy maize), no significant difference was found between microwave and conventional heating in terms of maximum diameter, temperature of maximum rate of diameter increase, or diameter vs. temperature behavior. These results suggest that there are no differences in the swelling behavior of common and modified maize starches between microwave and conventional heating. PMID:27474654

  12. Magnetic relaxation--coal swelling, extraction, pore size

    SciTech Connect

    Doetschman, D.C.

    1991-01-01

    The grant activities during this period fall into four categories: (1) Completion of preparatory work, (2) Procedure refinement and actual preparation of whole coal, coal residue, coal extract and swelled coal samples for NMR studies, (3) Related studies of coal photolysis that employ materials from preliminary extractions and that examine the u.v.-visible and mass spectra of the extracts and (4) Continued investigations of the pulsed EPR characteristics of the whole coal samples that were prepared in the first quarter of the grant.

  13. Fuel swelling and interaction layer formation in the SELENIUM Si and ZrN coated U(Mo) dispersion fuel plates irradiated at high power in BR2

    NASA Astrophysics Data System (ADS)

    Leenaers, A.; Van den Berghe, S.; Koonen, E.; Kuzminov, V.; Detavernier, C.

    2015-03-01

    In the framework of the SELENIUM project two full size flat fuel plates were produced with respectively Si and ZrN coated U(Mo) particles and irradiated in the BR2 reactor at SCK•CEN. Non-destructive analysis of the plates showed that the fuel swelling profiles of both SELENIUM plates were very similar to each other and none of the plates showed signs of pillowing or excessive swelling at the end of irradiation at the highest power position (local maximum 70% 235U). The microstructural analysis showed that the Si coated fuel has less interaction phase formation at low burn-up but at the highest burn-ups, defects start to develop on the IL-matrix interface. The ZrN coated fuel, shows a virtual absence of reaction between the U(Mo) and the Al, up to high fission densities after which the interaction layer formation starts and defects develop in the matrix near the U(Mo) particles. It was found and is confirmed by the SELENIUM (Surface Engineering of Low ENrIched Uranium-Molybdenum) experiment that there are two phenomena at play that need to be controlled: the formation of an interaction layer and swelling of the fuel. As the interaction layer formation occurs at the U(Mo)-matrix interface, applying a diffusion barrier (coating) at that interface should prevent the interaction between U(Mo) and the matrix. The U(Mo) swelling, observed to proceed at an accelerating rate with respect to fission density accumulation, is governed by linear solid state swelling and fission gas bubble swelling due to recrystallization of the fuel. The examination of the SELENIUM fuel plates clearly show that for the U(Mo) dispersion fuel to be qualified, the swelling rate at high burn-up needs to be reduced.

  14. Swelling of hydroxypropyl methylcellulose matrix tablets. 2. Mechanistic study of the influence of formulation variables on matrix performance and drug release.

    PubMed

    Gao, P; Skoug, J W; Nixon, P R; Ju, T R; Stemm, N L; Sung, K C

    1996-07-01

    We characterized the effect of hydroxypropyl methylcellulose (HPMC)/lactose ratio and HPMC viscosity grade (molecular weight) on solute release and swelling of matrix tablets. We used a semiquantitative optical imaging method to monitor the swelling of matrices with HPMC content from 20% to 80% (w/w) and four viscosity grades. Several aspects of the swelling process common to all formulations were revealed: (i) swelling is anisotropic with a preferential expansion in the axial direction, (ii) swelling is isotropic with respect to the gel layer thickness and composition in both axial and radial directions, (iii) the gel layer develops in three stages, and (iv) water penetration is Fickian in nature and essentially constant for all formulations. We monitored simultaneously drug, lactose, and HPMC release. Lactose and drug release rates were superimposed, indicating a similar diffusional release mechanism and no interaction with HPMC. The strong dependence of HPMC release on viscosity grade is explained on the basis of the concept of polymer disentanglement concentration. We analyzed drug release rates using a model for a reservoir-type release system that incorporates swelling kinetics. HPMC/lactose ratio modulates drug release rate by altering drug diffusivity, a function of gel composition. In contrast, HPMC viscosity grade impacts matrix dissolution and gel layer thickness development below a critical molecular weight. For slowly dissolving matrices containing high viscosity grade (> 4000 cps) HPMC, similar drug release rates are observed mainly due to the same drug diffusivity as a result of the identical gel composition and thickness. For fast dissolving matrices (< or = 100 cps) swelling inhomogeneity is proposed as being responsible for a higher apparent drug diffusivity and release rate. PMID:8818998

  15. Molecular accessibility in solvent swelled coal. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1992-05-29

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a nonswelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method has also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data show that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 nm). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of the coal, thus providing information on the importance of molecular shape.

  16. Molecular accessibility in solvent swelled coal. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1992-08-01

    An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a nonswelling solvent to eliminate any spin probes that are not trapped in the pores and the spin concentration measured. Comparing these spin probe measurements to DRIFT data have shown that the relative number distribution of acidic functionalities can be accurately predicted by the spin probe method. The spin probe method has also been used to predict the increase in elongated voids in Pittsburgh No. 8 (APCS No. 4) upon swelling with pyridine in agreement with independent SANS data. NMR relaxation data shows that it is possible to deduce the pore (accessibility) distribution as a function of size (up to 6 nm). It has also been possible by variable temperature and ENDOR measurements to determine the presence of hydrogen bonding as a function of pore shape and size. The advantage of the EPR method is that it permits molecules of selected shape and size to be used as probes of accessible regions of the coal, thus providing information on the importance of molecular shape.

  17. Equilibrium swelling of elastomeric materials in solvent environments

    SciTech Connect

    Green, P.F.

    1990-03-01

    The equilibrium swelling of silicones, fluorosilicones, VITON and ethylene-propylene-diene (EPDM) elastomers in an environment of the jet fuel JP4 was investigated. The volume of silicone and DPDM elastomers increased by approximately 100% when they were placed in a saturated environment of JP4. Conversely, the volume of the fluorosilicone elastomer increased by approximately 15% and that of VITON less than 1%. In acetone, a commonly used solvent, the equilibrium swelling of VITON and the fluorosilicone elastomer was excessive, on the order of 100%, wheras the silicone and EPDM elastomers exhibited small changes in dimensions. Reasons for these observations are discussed in detail. We also present a simple scheme by which one may, qualitatively, determine the dimensional stability of these elastomers in different solvents if the cohesive energy density of the solvent, which is readily available in a number of handbooks, is known. We also evaluated the vulnerability of some commonly used engineering thermoplastics to JP4. The results are tabulated. 13 refs., 6 figs., 3 tab.

  18. Pore-scale Modelling of Capillarity in Swelling Granular Materials

    NASA Astrophysics Data System (ADS)

    Hassanizadeh, S. M.; Sweijen, T.; Nikooee, E.; Chareyre, B.

    2015-12-01

    Capillarity in granular porous media is a common and important phenomenon in earth materials and industrial products, and therefore has been studied extensively. To model capillarity in granular porous media, one needs to go beyond current models which simulate either two-phase flow in porous media or mechanical behaviour in granular media. Current pore-scale models for two-phase flow such as pore-network models are tailored for rigid pore-skeletons, even though in many applications, namely hydro-mechanical coupling in soils, printing, and hygienic products, the porous structure does change during two-phase flow. On the other hand, models such as Discrete Element Method (DEM), which simulate the deformable porous media, have mostly been employed for dry or saturated granular media. Here, the effects of porosity change and swelling on the retention properties was studied, for swelling granular materials. A pore-unit model that was capable to construct the capillary pressure - saturation curve was coupled to DEM. Such that the capillary pressure - saturation curve could be constructed for varying porosities and amounts of absorbed water. The study material was super absorbent polymer particles, which are capable to absorb water 10's to 200 times their initial weight. We have simulated quasi-static primary imbibition for different porosities and amounts of absorbed water. The results reveal a 3 dimensional surface between capillary pressure, saturation, and porosity, which can be normalized by means of the entry pressure and the effective water saturation to a unique curve.

  19. Swelling Mechanisms of UO2 Lattices with Defect Ingrowths.

    PubMed

    Günay, Seçkin D

    2015-01-01

    The swelling that occurs in uranium dioxide as a result of radiation-induced defect ingrowth is not fully understood. Experimental and theoretical groups have attempted to explain this phenomenon with various complex theories. In this study, experimental lattice expansion and lattice super saturation were accurately reproduced using a molecular dynamics simulation method. Based on their resemblance to experimental data, the simulation results presented here show that fission induces only oxygen Frenkel pairs while alpha particle irradiation results in both oxygen and uranium Frenkel pair defects. Moreover, in this work, defects are divided into two sub-groups, obstruction type defects and distortion type defects. It is shown that obstruction type Frenkel pairs are responsible for both fission- and alpha-particle-induced lattice swelling. Relative lattice expansion was found to vary linearly with the number of obstruction type uranium Frenkel defects. Additionally, at high concentrations, some of the obstruction type uranium Frenkel pairs formed diatomic and triatomic structures with oxygen ions in their octahedral cages, increasing the slope of the linear dependence. PMID:26244777

  20. Textureless Macula Swelling Detection with Multiple Retinal Fundus Images

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Tobin Jr, Kenneth William; Grisan, Enrico; Favaro, Paolo; Ruggeri, Alfredo; Chaum, Edward

    2010-01-01

    Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relatively low cost, these cameras can be employed by operators with limited training for telemedicine or Point-of-Care applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyse the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic algorithms to measure features from the reconstructed image which are useful in Point-of-Care automated diagnosis of early macular edema, e.g., before the appearance of exudation. The technique presented is divided into three parts: first, a preprocessing technique simultaneously enhances the dark microstructures of the macula and equalises the image; second, all available views are registered using non-morphological sparse features; finally, a dense pyramidal optical flow is calculated for all the images and statistically combined to build a naiveheight- map of the macula. Results are presented on three sets of synthetic images and two sets of real world images. These preliminary tests show the ability to infer a minimum swelling of 300 microns and to correlate the reconstruction with the swollen location.

  1. Shape instability on swelling of a stretched nematic elastomer filament.

    PubMed

    Cheewaruangroj, N; Terentjev, E M

    2015-10-01

    Liquid crystalline elastomers combine the ordering properties of liquid crystals with elasticity of crosslinked polymer networks. In monodomain (permanently aligned) elastomers, altering the orientational (nematic) order causes changes in the equilibrium sample length, which is the basis of the famous effect of large-amplitude reversible mechanical actuation. The stimulus for this effect could be a change in temperature, or illumination by light in photosensitized elastomers, but equally the nematic order changes by mixing with a solvent. This work theoretically investigates a competition between the spontaneous contraction on swelling of a monodomain nematic elastomer and the externally imposed stretching. We find that this competition leads to bistability in the system and allows a two-phase separation between a nematic state with lower swelling and an isotropic state with higher solvent concentration. We calculated the conditions in which the instability occurs as well as the mechanical and geometric parameters of equilibrium states. Being able to predict how this instability arises will provide opportunities for exploiting nematic elastomer filaments.

  2. Swelling, Compressibility, and Phase Behavior of Soft Ionic Microgels

    NASA Astrophysics Data System (ADS)

    Denton, Alan

    Soft colloids have inspired great attention recently for their rich and tunable materials properties. Particular interest has focused on microgels - microscopic cross-linked polymer gel particles that, when dispersed in water, become swollen and can acquire charge through dissociation of counterions. Electrostatic interparticle interactions strongly influence the structure and thermodynamics of ionic microgel suspensions*. Permeability to solvent molecules and small ions creates a competition between elastic and electrostatic forces that determines equilibrium particle sizes. Swelling can be controlled by adjusting temperature, pH, and salt concentration, with applications to chemical/biosensing and targeted drug delivery. By combining molecular dynamics and Monte Carlo simulation with Poisson-Boltzmann theory of electrostatics and Flory-Rehner theory of swollen polymer networks, we investigate swelling and compressibility of ionic microgel particles and implications for thermodynamic phase behavior of bulk suspensions at concentrations approaching and exceeding hard-sphere close packing. Predictions for particle size and osmotic pressure are compared with available experimental data. This work was supported by the National Science Foundation under Grant No. DMR-1106331.

  3. Hereditary Angioedema Attacks: Local Swelling at Multiple Sites.

    PubMed

    Hofman, Zonne L M; Relan, Anurag; Hack, C Erik

    2016-02-01

    Hereditary angioedema (HAE) patients experience recurrent local swelling in various parts of the body including painful swelling of the intestine and life-threatening laryngeal oedema. Most HAE literature is about attacks located in one anatomical site, though it is mentioned that HAE attacks may also involve multiple anatomical sites simultaneously. A detailed description of such multi-location attacks is currently lacking. This study investigated the occurrence, severity and clinical course of HAE attacks with multiple anatomical locations. HAE patients included in a clinical database of recombinant human C1-inhibitor (rhC1INH) studies were evaluated. Visual analog scale scores filled out by the patients for various symptoms at various locations and investigator symptoms scores during the attack were analysed. Data of 219 eligible attacks in 119 patients was analysed. Thirty-three patients (28%) had symptoms at multiple locations in anatomically unrelated regions at the same time during their first attack. Up to five simultaneously affected locations were reported. The observation that severe HAE attacks often affect multiple sites in the body suggests that HAE symptoms result from a systemic rather than from a local process as is currently believed. PMID:25527240

  4. Swelling Mechanisms of UO2 Lattices with Defect Ingrowths

    PubMed Central

    Günay, Seçkin D.

    2015-01-01

    The swelling that occurs in uranium dioxide as a result of radiation-induced defect ingrowth is not fully understood. Experimental and theoretical groups have attempted to explain this phenomenon with various complex theories. In this study, experimental lattice expansion and lattice super saturation were accurately reproduced using a molecular dynamics simulation method. Based on their resemblance to experimental data, the simulation results presented here show that fission induces only oxygen Frenkel pairs while alpha particle irradiation results in both oxygen and uranium Frenkel pair defects. Moreover, in this work, defects are divided into two sub-groups, obstruction type defects and distortion type defects. It is shown that obstruction type Frenkel pairs are responsible for both fission- and alpha-particle-induced lattice swelling. Relative lattice expansion was found to vary linearly with the number of obstruction type uranium Frenkel defects. Additionally, at high concentrations, some of the obstruction type uranium Frenkel pairs formed diatomic and triatomic structures with oxygen ions in their octahedral cages, increasing the slope of the linear dependence. PMID:26244777

  5. Swelling assisted photografting of itaconic acid onto sodium alginate membranes

    NASA Astrophysics Data System (ADS)

    Taşkın, Gülşen; Şanlı, Oya; Asman, Gülsen

    2011-09-01

    Grafting of itaconic acid (IA) was achieved onto sodium alginate (NaAlg) membranes by using UV-radiation. Process was performed under nitrogen atmosphere and benzophenone (BP) was used as a photoinitiator. Membranes were preswelled before the polymerization process and ethanol was determined as the best swelling agent among the studied solvents. The effect of polymerization time, initiator and monomer concentrations on the grafting efficiency were investigated. The best conditions for optimum grafting were obtained with IA concentration of 1.0 M, a BP concentration of 0.1 M and a reaction time of 4 h at 25 °C. Under these conditions grafting efficiency for NaAlg-g-IA membranes was found to be 14% (w/w). To obtain further increase in grafting efficiency membranes were also preswelled in IA and BP solutions and polymerization was carried out at different temperatures after UV polymerization. Grafted membranes were characterized by using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Effect of grafting on membrane properties such as intrinsic viscosity and swelling percentage were also determined.

  6. Hereditary Angioedema Attacks: Local Swelling at Multiple Sites.

    PubMed

    Hofman, Zonne L M; Relan, Anurag; Hack, C Erik

    2016-02-01

    Hereditary angioedema (HAE) patients experience recurrent local swelling in various parts of the body including painful swelling of the intestine and life-threatening laryngeal oedema. Most HAE literature is about attacks located in one anatomical site, though it is mentioned that HAE attacks may also involve multiple anatomical sites simultaneously. A detailed description of such multi-location attacks is currently lacking. This study investigated the occurrence, severity and clinical course of HAE attacks with multiple anatomical locations. HAE patients included in a clinical database of recombinant human C1-inhibitor (rhC1INH) studies were evaluated. Visual analog scale scores filled out by the patients for various symptoms at various locations and investigator symptoms scores during the attack were analysed. Data of 219 eligible attacks in 119 patients was analysed. Thirty-three patients (28%) had symptoms at multiple locations in anatomically unrelated regions at the same time during their first attack. Up to five simultaneously affected locations were reported. The observation that severe HAE attacks often affect multiple sites in the body suggests that HAE symptoms result from a systemic rather than from a local process as is currently believed.

  7. Shrinkage/swelling of compacted clayey loose and dense soils

    NASA Astrophysics Data System (ADS)

    Nowamooz, Hossein; Masrouri, Farimah

    2009-11-01

    This Note presents an experimental study performed on expansive compacted loose and dense samples using osmotic oedometers. Several successive wetting and drying cycles were applied in a suction range between 0 and 8 MPa under different values of constant net vertical stress (15, 30, and 60 kPa). During the suction cycles, the dense samples showed cumulative swelling strains, while the loose samples showed volumetric shrinkage accumulation. At the end of the suction cycles, the volumetric strains converged to an equilibrium stage that indicated elastic behavior of the swelling soil for any further hydraulic variations. At this stage, the compression curves for the studied soil at the different imposed suctions (0, 2, and 8 MPa) converged towards the saturated state curve for the high applied vertical stresses. We defined this pressure as the saturation stress(P). The compression curves provided sufficient data to examine the soil mechanical behavior at the equilibrium stage. To cite this article: H. Nowamooz, F. Masrouri, C. R. Mecanique 337 (2009).

  8. Brain herniation

    MedlinePlus

    ... herniation; Uncal herniation; Subfalcine herniation; Tonsillar herniation; Herniation - brain ... Brain herniation occurs when something inside the skull produces pressure that moves brain tissues. This is most ...

  9. Swelling and osmotic flow in a potential host rock

    NASA Astrophysics Data System (ADS)

    Horseman, S. T.; Harrington, J. F.; Noy, D. J.

    Measurements of osmotic and hydraulic permeability are reported for a series of tests conducted on Opalinus Clay samples from the Mt. Terri underground research laboratory in the Jura Mountains of NE Switzerland. Osmotic flow was observed across discs of this clayshale separating 0.245 M NaCl solution from distilled water. Pressure transients monitored during constant flow rate testing were analysed to give permeability and specific storage values. The mean permeability normal to bedding of the two Opalinus Clay specimens was 7.9 × 10 -21 m 2. The mean specific storage based on all reliable determinations was 4.1 × 10 -4 m -1. Values calculated from the steady-state pressure gradients established during constant flow rate testing were very close to those obtained by mathematical analysis of pressure transients. The calculation of the transients was carried out using a new model of flow and solute transport which included terms for the osmotic coupling. The form of the pressure transients and the magnitude of the strain seen during the tests lead to a revision to the definition of solid phase compressibility to incorporate a term dependent upon the osmotic coupling coefficient. Steady-state osmotic flow rates were in the range 0.1-0.6 μL h -1 when the specimens were placed between a sodium chloride solution with a theoretical osmotic pressure of 1.19 MPa and distilled water. Transient flow rates were substantially larger. Membrane efficiencies were found to be relatively low, ranging from 1% to 6% (mean around 4%). The mean osmotic permeability normal to bedding was 3.5 × 10 -22 m 2. Specific storage and pore compressibility values were substantially larger than anticipated, suggesting that the volumetric strain of the clayshale under the conditions of laboratory testing must be largely determined by quasi-elastic deformation processes such as swelling and crack dilation. To test this hypothesis, a 3-D swelling test was performed on a cubic specimen of the same

  10. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    NASA Astrophysics Data System (ADS)

    Shao, Lin; Wei, C.-C.; Gigax, J.; Aitkaliyeva, A.; Chen, D.; Sencer, B. H.; Garner, F. A.

    2014-10-01

    Ion irradiation has been widely used to simulate neutron-induced radiation damage. There are a number of features of ion-induced damage that differ from neutron-induced damage, however, and these differences require investigation before ion data can be confidently used to predict behavior arising from neutron bombardment. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. It was observed that the depth dependence of void swelling does not follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then moves to progressively deeper and higher-damage depths during continued irradiation. This indicates a strong initial suppression of void nucleation in the peak damage region that is eventually overcome with continued irradiation. Using the Boltzmann transport equation method, this phenomenon is shown to be due to depth-dependent defect imbalances created under ion irradiation. These findings demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extraction and interpretation of ion-induced swelling data.

  11. Swelling of poly(N-isopropylacrylamide) P(NIPA)-based hydrogels with bacterial-synthesized prodigiosin for localized cancer drug delivery.

    PubMed

    Danyuo, Y; Dozie-Nwachukwu, S; Obayemi, J D; Ani, C J; Odusanya, O S; Oni, Y; Anuku, N; Malatesta, K; Soboyejo, W O

    2016-02-01

    We present the results of swelling experiments on poly(N-isopropylacrylamide) P(NIPA)-based hydrogels. The swelling characteristics of P(NIPA)-based homo-polymer and P(NIPA)-based co-polymers with Acrylamide (AM) and Butyl Methacrylate (BMA), were studied using weight gain experiments. The swelling due to the uptake of biosynthesized cancer drug, prodigiosin (PG), was compared to swelling in controlled environments (distilled water (DW), paclitaxel™ (PT) and bromophenol blue (BB)). PG was synthesized with Serratia marcescens (SM) subsp. marcescens bacteria. The mechanisms of drug diffusion and swelling of P(NIPA)-based hydrogels are also elucidated along with characterizing the heterogeneous porous structure of the P(NIPA)-based hydrogels. High Performance Liquefied Chromatography (HPLC) analysis revealed the purity of the biosynthesized prodigiosin to be 92.8%. PG was then absorbed by P(NIPA)-based hydrogels at temperatures between 28-48°C. This is a temperature range that might be encountered during the implantation of biomedical devices for localized cancer treatment via drug delivery and hyperthermia. The results obtained are shown to provide insights for the design of implantable biomedical devices for the localized treatment of breast cancer.

  12. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    DOE PAGES

    Shao, Lin; Wei, C. -C.; Gigax, J.; Aitkaliyeva, A.; Chen, D.; Sencer, B. H.; Garner, F. A.

    2014-06-10

    Ion irradiation has been widely used to simulate radiation damage induced by neutrons. However, there are a number of features of ion-induced damage that differ from neutron-induced damage, and these differences require investigation before behavior arising from neutron bombardment can be confidently predicted from ion data. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. The depth dependence of void swelling was observed notmore » to follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then, during continued irradiation, move to progressively deeper and higher-damage depths. This indicates a strong initial suppression of void nucleation in the peak damage region that continued irradiation eventually overcomes. This phenomenon is shown by the Boltzmann transport equation method to be due to depth-dependent defect imbalances created under ion irradiation. These findings thus demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extracting and interpreting ion-induced swelling data.« less

  13. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    SciTech Connect

    Shao, Lin; Wei, C. -C.; Gigax, J.; Aitkaliyeva, A.; Chen, D.; Sencer, B. H.; Garner, F. A.

    2014-06-10

    Ion irradiation has been widely used to simulate radiation damage induced by neutrons. However, there are a number of features of ion-induced damage that differ from neutron-induced damage, and these differences require investigation before behavior arising from neutron bombardment can be confidently predicted from ion data. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. The depth dependence of void swelling was observed not to follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then, during continued irradiation, move to progressively deeper and higher-damage depths. This indicates a strong initial suppression of void nucleation in the peak damage region that continued irradiation eventually overcomes. This phenomenon is shown by the Boltzmann transport equation method to be due to depth-dependent defect imbalances created under ion irradiation. These findings thus demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extracting and interpreting ion-induced swelling data.

  14. Experimental study and modeling of swelling and bubble growth in carbon nanofiber filled mesophase pitch during carbonization

    NASA Astrophysics Data System (ADS)

    Calebrese, Christopher

    Graphite and all carbon bipolar plates show corrosion resistance in fuel cells and provide good electrical conductivity. These materials typically need to be individually machined, a time consuming and costly process. Mesophase pitch is used to manufacture carbon fibers and carbon-carbon composites. This material provides a good starting point for the production of a moldable, all carbon bipolar plate. However, processing of mesophase pitch to produce all carbon materials requires a time intensive oxidation step to prevent swelling during carbonization. In this work, carbon nanofibers were used to reduce swelling in mesophase pitch. It was found that the increase in viscosity with the addition of carbon nanofibers was responsible for the reduction in swelling. The influence of the filler became apparent above the percolation threshold. At loadings below the percolation threshold, the swelling of the mesophase pitch was not reduced after carbonization. The swelling of the mesophase pitch at a given carbon nanofiber loading was also dependent on the length of the carbon nanofibers. Longer carbon nanofibers led to greater increases in the viscosity of the melt and thus led to greater reduction in swelling. The final carbon product was evaluated for use as a low temperature fuel cell bipolar plate material. Constraining the mesophase pitch during carbonization led to a final product with strength and electrical conductivity comparable to current composite bipolar plate materials. The addition of micron size chopped glass fibers with a softening point near 850°C and carbon nanofibers led to a final product with air permeability less than that of graphite. A spherically symmetric, single bubble growth model was also developed. The model included temperature dependence, liquid to bubble mass transfer and reactions in the system. Results from simulations showed that that the increase in viscosity due to the addition of carbon nanofibers slows the growth of bubbles, but

  15. Swell dissipation from 10 years of Envisat advanced synthetic aperture radar in wave mode

    NASA Astrophysics Data System (ADS)

    Stopa, Justin E.; Ardhuin, Fabrice; Husson, Romain; Jiang, Haoyu; Chapron, Bertrand; Collard, Fabrice

    2016-04-01

    Swells are found in all oceans and strongly influence the wave climate and air-sea processes. The poorly known swell dissipation is the largest source of error in wave forecasts and hindcasts. We use synthetic aperture radar data to identify swell sources and trajectories, allowing a statistically significant estimation of swell dissipation. We mined the entire Envisat mission 2003-2012 to find suitable storms with swells (13 < T < 18 s) that are observed several times along their propagation. This database of swell events provides a comprehensive view of swell extending previous efforts. The analysis reveals that swell dissipation weakly correlates with the wave steepness, wind speed, orbital wave velocity, and the relative direction of wind and waves. Although several negative dissipation rates are found, there are uncertainties in the synthetic aperture radar-derived swell heights and dissipation rates. An acceptable range of the swell dissipation rate is -0.1 to 6 × 10-7 m-1 with a median of 1 × 10-7 m-1.

  16. Swelling behavior of O-alkylated APCS coals as examined by the EPR spin probe method

    SciTech Connect

    Ding, Ruisong; Tucker, D.; Kispert, L.D.

    1995-12-31

    Known O-alkylation procedures have been used to derivatize the carboxyl and hydroxyl groups in the APCS coals Lewiston-Stockton, Wyodak-Anderson, Beulah-Zap, Illinois {number_sign}6, Upper Freeport, and Pittsburgh {number_sign}8. In general the resulting decrease in hydrogen bonding reduced the cyclical variation in nitroxide spin probe retention observed for nonalkylated coals when small amounts (<1%) of pyridine are present in the toluene swelling solvent. An increase in spin probe retention by the O-alkylated coals relative to the underivatized coals indicates a more open arrangement in the coal due to a decrease in attractive forces, confirming that microporosity increases with increasing rank.

  17. Three-dimensional simulations of plume-lithosphere interaction at the hawaiian swell

    PubMed

    Moore; Schubert; Tackley

    1998-02-13

    Rapid lithospheric thinning by mantle plumes has not been achieved in numerical experiments performed to date. Efficient thinning depends on small-scale instabilities that convectively remove lithospheric material. These instabilities are favored by hotter plumes or stronger temperature dependence of viscosity, and a simple scaling independent of rheology controls their onset. This scaling allows extrapolation of the results of numerical experiments to the Earth's mantle. Mantle plumes between 100 and 150 kelvins hotter than the background mantle should exhibit small-scale convective rolls aligned with the plate motion. The unusual variation in heat flow across the Hawaiian swell may be due to such instabilities. It was found that the spreading of the plume creates a downwelling curtain of material that isolates it from the rest of the mantle for distances of at least 1000 kilometers from the plume origin. This isolation has important consequences for the geochemical heterogeneity of the lithosphere and upper mantle.

  18. A tender swelling of the left posterior mandible: An unusual case.

    PubMed

    Grewal, Harshaminder K; Goel, Poonam; Batra, Ranmeet; Chopra, Sumit

    2014-05-01

    Tender swellings of the mandible are majorly due to inflammatory lesions like infected dental cyst, peri-apical abscess or neoplasms like osteoblastomas, cementoblastomas, osteosarcoma and intraosseous squamous cell carcinoma. Florid cemento-osseous dysplasia is a subgroup of cemento-osseous dysplasia typically found in middle-aged black women as multiple, non-tender, diffuse, lobulated radio-opacities distributed throughout the maxilla and mandible, which are usually bilaterally symmetrical. Histologically, they are composed of proliferating fibrous connective tissue stroma containing foci of cementum, osteoid and bone. Florid cemento-osseous dysplasia is rare in Indian population and among all cases of florid cemento-osseous dysplasia, almost 97% of the cases reported till date are in females. The present case describes florid cemento-osseous dysplasia in a 26-year-old male who reported with pain in the left mandibular premolar region. PMID:25328327

  19. Role of dietary polyphenols in attenuating brain edema and cell swelling in cerebral ischemia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyphenols are natural substances with variable phenolic structures and are enriched in vegetables, fruits, grains, bark, roots, tea, and wine. There are over 8000 polyphenolic structures identified in plants, but edible plants contain only several hundred polyphenolic structures. Recent interest...

  20. Liquid crystalline systems of phytantriol and glyceryl monooleate containing a hydrophilic protein: Characterisation, swelling and release kinetics.

    PubMed

    Rizwan, S B; Hanley, T; Boyd, B J; Rades, T; Hook, S

    2009-11-01

    Swelling and phase behaviour of phytantriol and glyceryl monooleate (GMO) matrices with varying water loadings were investigated. Release of a model protein, FITC-Ova was subsequently examined. Polarised light microscopy and small angle X-ray scattering analysis showed that the addition of FITC-Ova only altered the liquid crystalline structure of phytantriol matrices at low water loadings, and that postrelease study, the phase structure of matrices at both low and high loading reflected that of the binary system. Addition of FITC-Ova to GMO matrices also altered the liquid crystalline structure when compared to the respective binary system at low but not at high loading. All samples analysed after the release study had transformed to the reverse hexagonal phase (H(II)). Swelling studies revealed a faster and more extensive swelling of GMO when compared to phytantriol. Release of FITC-Ova from phytantriol matrices was faster and occurred to a greater extent most likely due to the conversion of GMO matrices into the H(II) phase. No effect on release as a function of initial water content was observed for either lipid. We have confirmed that phytantriol based liquid crystalline matrices can sustain the release of a hydrophilic protein, suggesting its suitability as a potential sustained antigen-delivery system.

  1. Longitudinal design for sonographic measurement of median nerve swelling with controlled exposure to physical work using an animal model

    PubMed Central

    Roll, Shawn C.; Evans, Kevin D.; Volz, Kevin R.; Sommerich, Carolyn M.

    2013-01-01

    This study examined the feasibility of a longitudinal design to sonographically measure swelling of the median nerve due to controlled exposure to a work task and to evaluate the relationship of changes in morphology to diagnostic standards. Fifteen macaca fascicularis pinched a lever in various wrist positions at a self-regulated pace (8 hours/day, 5 days/week, 18–20 weeks). Nerve conduction velocity (NCV) and cross-sectional area (CSA) were obtained every two weeks from baseline through working and a 6-week recovery. Trending across all subjects showed that NCV slowed and CSA at the carpal tunnel increased in the working arm, while no changes were observed in CSA either at the forearm or for any measure in the non-working arm. There was a small negative correlation between NCV and CSA in the working arm. This study provides validation that swelling can be observed using a longitudinal design. Longitudinal human studies are needed to describe the trajectory of nerve swelling for early identification of median nerve pathology. PMID:24139197

  2. Effect of pre-implanted helium on void swelling evolution in self-ion irradiated HT9

    NASA Astrophysics Data System (ADS)

    Getto, E.; Jiao, Z.; Monterrosa, A. M.; Sun, K.; Was, G. S.

    2015-07-01

    Void evolution in Fe++-irradiated ferritic-martensitic alloy HT9 was characterized in the temperature range of 400-480 °C between doses of 25 and 375 displacements per atom (dpa) with pre-implanted helium levels of 0-100 appm. A systematic study using depth profiling in cross-section samples was conducted to determine a valid region of analysis between 300 and 700 nm from the surface, which excluded effects due to the injected interstitial and the surface. Pre-implanted helium was found to promote void swelling at low doses by shortening the nucleation regime and to retard void growth at doses in the transient regime by enhancement of nucleation of small voids. Swelling was found to peak at a temperature of 460 °C. The primary effect of temperature was on the nucleation regime; nucleation regime was the shortest at 460 °C compared to that at 440 and 480 °C. The growth rate of voids was temperature-invariant. Steady state swelling was reached at 460 °C between 188 and 375 dpa at a rate of 0.02%/dpa.

  3. Effect of initial total monomer concentration on the swelling behavior of cationic acrylamide-based hydrogels

    SciTech Connect

    Baker, J.P.; Hong, L.H.; Blanch, H.W.; Prausnitz, J.M. . Dept. of Chemical Engineering Lawrence Berkeley Lab., CA . Chemical Sciences Div.)

    1994-03-14

    The aqueous equilibrium swelling properties of a series of lightly-cross-linked cationic hydrogels based on acrylamide and [(methacrylamido) propyl] trimethylammonium chloride (MAPTAC) were measured as a function of initial total monomer concentration % T (w/v) and ionic strength. Swelling is a strong decreasing function of rising % T; the 10 % T hydrogel obtained a 17-fold larger swelling ratio (g of swollen hydrogel/g of dry hydrogel) in pure water compared to the 40 % T hydrogel. Good agreement is obtained between measured swelling equilibria in aqueous sodium chloride and that calculated from a Flory-type swelling model including ideal Donnan equilibria provided that an adjustable parameter is introduced into the swelling model for hydrogels in pure water. The experimental results presented here indicate that network-chain interpenetration increases with rising % T.

  4. A new insight from space into swell propagation and crossing in the global oceans

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Ming

    2016-05-01

    A half-century ago, it was recorded that ocean swells can propagate up to halfway around the globe. However, from a global perspective, how ocean swells propagate in the global oceans has yet to be depicted. To date, synthetic aperture radar (SAR) is the only available remote sensing instrument to measure the two-dimensional information of ocean surface waves. Here a 10 year (2002-2012) global wave data set of the spaceborne advanced SAR on board the European Space Agency's satellite Envisat and the global wind data set of the WindSat were used to (1) depict the propagation routes of ocean swells in the global oceans, (2) identify four distinguished crossing swell "pools," and (3) interpret how these pools are formed. Together, these findings yield a new insight into ocean swells propagation and the consequent occurrence of crossing swells on a global ocean scale from space, which will further deepen our understanding of nature of ocean.

  5. The correlation between swelling and radiation-induced segregation in iron-chromium-nickel alloys.

    SciTech Connect

    Allen, T. R.; Busby, J. T.; Kenik, E. A.; Was, G. S.

    1998-03-05

    The magnitudes of both void swelling and radiation-induced segregation (RIS) in iron-chromium-nickel alloys are dependent on bulk alloy composition. Because the diffusivity of nickel via the vacancy flux is slow relative to chromium, nickel enriches and chromium depletes at void surfaces during irradiation. This local composition change reduces the subsequent vacancy flux to the void, thereby reducing void swelling. In this work, the resistance to swelling from major element segregation is estimated using diffusivities derived from grain boundary segregation measurements in irradiated iron-chromium-nickel alloys. The resistance to void swelling in iron- and nickel-base alloys correlates with the segregation and both are functions of bulk alloy composition. Alloys that display the greatest amount of nickel enrichment and chromium depletion are found to be most resistant to void swelling, as predicted. Additionally, swelling is shown to be greater in alloys in which the RIS profiles are slow to develop.

  6. Microscale Patterning of Thermoplastic Polymer Surfaces by Selective Solvent Swelling

    PubMed Central

    Rahmanian, Omid; Chen, Chien-Fu; DeVoe, Don L.

    2012-01-01

    A new method for the fabrication of microscale features in thermoplastic substrates is presented. Unlike traditional thermoplastic microfabrication techniques, in which bulk polymer is displaced from the substrate by machining or embossing, a unique process termed orogenic microfabrication has been developed in which selected regions of a thermoplastic surface are raised from the substrate by an irreversible solvent swelling mechanism. The orogenic technique allows thermoplastic surfaces to be patterned using a variety of masking methods, resulting in three-dimensional features that would be difficult to achieve through traditional microfabrication methods. Using cyclic olefin copolymer as a model thermoplastic material, several variations of this process are described to realize growth heights ranging from several nanometers to tens of microns, with patterning techniques include direct photoresist masking, patterned UV/ozone surface passivation, elastomeric stamping, and noncontact spotting. Orogenic microfabrication is also demonstrated by direct inkjet printing as a facile photolithography-free masking method for rapid desktop thermoplastic microfabrication. PMID:22900539

  7. Simulation study of sulfonate cluster swelling in ionomers

    NASA Astrophysics Data System (ADS)

    Allahyarov, Elshad; Taylor, Philip L.; Löwen, Hartmut

    2009-12-01

    We have performed simulations to study how increasing humidity affects the structure of Nafion-like ionomers under conditions of low sulfonate concentration and low humidity. At the onset of membrane hydration, the clusters split into smaller parts. These subsequently swell, but then maintain constant the number of sulfonates per cluster. We find that the distribution of water in low-sulfonate membranes depends strongly on the sulfonate concentration. For a relatively low sulfonate concentration, nearly all the side-chain terminal groups are within cluster formations, and the average water loading per cluster matches the water content of membrane. However, for a relatively higher sulfonate concentration the water-to-sulfonate ratio becomes nonuniform. The clusters become wetter, while the intercluster bridges become drier. We note the formation of unusual shells of water-rich material that surround the sulfonate clusters.

  8. Fibromatosis Colli - A Rare Cytological Diagnosis In Infantile Neck Swellings

    PubMed Central

    Jetley, Sujata; Jairajpuri, Zeeba; Husain, Musharraf

    2014-01-01

    Fibromatosis colli or sternocleidomastoid tumour is a rare cause of benign neck mass in infants. It is a self limiting fibroblastic lesion usually presenting with torticollis and a history of birth trauma.It is one of the few causes in which Fine Needle Aspiration Cytology (FNAC) is indicated in a neonate to confirm the diagnosis and to differentiate it from other congenital, inflammatory and neoplastic causes. FNAC provides a rapid, cost-effective, reliable, non invasive method of diagnosis resulting in conservative management of these lesions. We present two interesting cases of neck swelling in infants where FNAC performed as the first diagnostic procedure was instrumental in establishing the diagnosis of fibromatosis colli thus avoiding unnecessary surgical intervention. PMID:25584233

  9. Mechanical and swelling properties of PDMS interpenetrating polymer networks

    NASA Astrophysics Data System (ADS)

    Cohen, Claude; Yoo, Seong Hyun

    2006-03-01

    Poly(dimethylsiloxane) (PDMS) interpenetrating networks (IPNs) of a large and a small molar mass PDMS were prepared. Six series of IPNs were obtained by first tetra-functionally end-linking long vinyl-terminated PDMS neat or in a 50 per cent solution with unreactive PDMS chains. These networks were then dried and swollen with short reactive telechelic PDMS that were subsequently end-linked. We found that the correlation between modulus (E) and equilibrium swelling (Q) in toluene of the PDMS IPNs obeys a scaling relation identical to that of normal uni-modal PDMS networks. The results of the toughness of the networks represented by the energy required to rupture them were analyzed in terms of a recent model by Okumura (Europhysics Letters 67(3), 470, 2004). A modified version of this model that assumes each component of the double network to be subjected to an equal stress gives a good representation of the data.

  10. Co-hydrogasification of lignocellulosic biomass and swelling coal

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Zheng, N.; Wang, J.

    2016-08-01

    The hydrogasification of pine wood (PW) and rice husk (RH) was carried out in a two-stage fixed-bed reactor to investigate the effects of hydrogen pressure and hydrocracking temperature on the yields of gas and tar compositions. The elevation in hydrogen pressure promoted the conversion of two biomasses, leading to the improvement in gaseous hydrocarbons but resulted in a decrease in the yield of BTX (benzene, toluene and xylene). The increased severity of hydrocracking boosted the yield of methane, ethane and BTX mainly at the expense of heavy compounds in tar for PW under 1 MPa. The co-hydrogasification of biomass and DWG swelling coal chiefly showed a synergistic effect on the yields of BTX and PCX (phenol, cresol and xylenol) at 500 °C hydrocracking temperature under 5 MPa.

  11. Idiopathic facial swelling secondary to sickle cell anaemia

    PubMed Central

    Moghe, Swapnil; Pillai, Ajay; Guru, Kanishka Navin; Nair, Preeti P

    2012-01-01

    Sickle cell disease is a common inherited autosomal disease that is characterised by abnormally shaped (sickle-shaped) red blood cells (RBCs). It can involve virtually any organ system. The clinical manifestations of sickle cell disease vary and are classified as vaso-occlusion, chronic anaemia and infection. The imaging appearances of central nervous system and musculoskeletal involvement by sickle cell disease have been well documented; however, involvement of the head and neck region is often unreported, although it is not uncommon. In the head and neck, sickle cell disease can involve the inner ears, orbits, paranasal sinuses, bones, lymph nodes and vessels. This paper describes a case of idiopathic facial swelling associated with sickle cell disease in a young patient. PMID:23060382

  12. Magnetic resonance imaging of clays: swelling, sedimentation, dissolution

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey; Furo, Istvan

    2010-05-01

    measure of clay distribution in extended samples during different physical processes such as swelling, dissolution, and sedimentation on the time scale from minutes to years [1-3]. To characterize the state of colloids that form after/during clay swelling the water self-diffusion coefficient was measured on a spatially resolved manner. Both natural clays and purified and ion-exchanged montmorillonite clays were investigated. The primary variables were clay composition and water ionic strength. These results have a significant impact for engineering barriers for storage of spent nuclear fuel where clay erosion by low salinity water must be addressed. Presented methods were developed under the motivation of using bentonite clays as a buffer medium to build in-ground barriers for the encapsulation of radioactive waste. Nevertheless, the same approaches can be found suitable in other applications in soil and environmental science to study other types of materials as they swell, dissolve, erode, or sediment. Acknowledgements: This work has been supported by the Swedish Nuclear Fuel and Waste Management Co (SKB) and the Swedish Research Council VR. [1] N. Nestle, T. Baumann, R. Niessner, Magnetic resonance imaging in environmental science. Environ. Sci. Techn. 36 154A (2002). [2] S. V. Dvinskikh, K. Szutkowski, I. Furó. MRI profiles over a very wide concentration ranges: application to swelling of a bentonite clay. J. Magn. Reson. 198 146 (2009). [3] S. V. Dvinskikh, I. Furó. Magnetic resonance imaging and nuclear magnetic resonance investigations of bentonite systems. Technical Report, TR-09-27, SKB (2009), www.skb.se.

  13. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization.

    PubMed

    Sen, Swati; Kundagrami, Arindam

    2015-12-14

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton's law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization. PMID:26671401

  14. Swelling of two-dimensional polymer rings by trapped particles.

    PubMed

    Haleva, E; Diamant, H

    2006-09-01

    The mean area of a two-dimensional Gaussian ring of N monomers is known to diverge when the ring is subject to a critical pressure differential, p c ~ N -1. In a recent publication (Eur. Phys. J. E 19, 461 (2006)) we have shown that for an inextensible freely jointed ring this divergence turns into a second-order transition from a crumpled state, where the mean area scales as [A]~N-1, to a smooth state with [A]~N(2). In the current work we extend these two models to the case where the swelling of the ring is caused by trapped ideal-gas particles. The Gaussian model is solved exactly, and the freely jointed one is treated using a Flory argument, mean-field theory, and Monte Carlo simulations. For a fixed number Q of trapped particles the criticality disappears in both models through an unusual mechanism, arising from the absence of an area constraint. In the Gaussian case the ring swells to such a mean area, [A]~ NQ, that the pressure exerted by the particles is at p c for any Q. In the freely jointed model the mean area is such that the particle pressure is always higher than p c, and [A] consequently follows a single scaling law, [A]~N(2) f (Q/N), for any Q. By contrast, when the particles are in contact with a reservoir of fixed chemical potential, the criticality is retained. Thus, the two ensembles are manifestly inequivalent in these systems. PMID:17028790

  15. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

    NASA Astrophysics Data System (ADS)

    Sen, Swati; Kundagrami, Arindam

    2015-12-01

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton's law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization.

  16. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

    SciTech Connect

    Sen, Swati; Kundagrami, Arindam

    2015-12-14

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton’s law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization.

  17. Effects of titanium additions to austenitic ternary alloys on microstructural evolution and void swelling

    SciTech Connect

    Okita, T; Wolfer, W G; Garner, F A; Sekimura, N

    2003-12-01

    Ternary austenitic model alloys were modified with 0.25 wt.% titanium and irradiated in FFTF reactor at dose rates ranging over more than two orders in magnitude. While lowering of dose rate strongly increases swelling by shortening the incubation dose, the steady state swelling rate is not affected by dose rate. Although titanium addition strongly alters the void microstructure, swelling at {approx} 420 C does not change with titanium additions, but the sensitivity to dose rate is preserved.

  18. Map Showing Areas Containing Swelling Clay in the Morrison Quadrangle, Jefferson County, Colorado

    USGS Publications Warehouse

    Scott, Glenn R.

    1972-01-01

    Formations that contain clays having swelling pressures higher than 2,500 pounds per square foot (as measured by the Potential Volume Change meter) are listed in order of decreasing swelling pressure: Denver Formation, Pierre Shale, Laramie Formation, Green Mountain Conglomerate, Fox Hills Sandstone, and Arapahoe Formation. Some landslides derived from these formations also contain swelling clay and are mapped with the bedrock formations listed above.

  19. Specimen Machining for the Study of the Effect of Swelling on CGR in PWR Environment.

    SciTech Connect

    Teysseyre, Sebastien Paul

    2015-06-01

    This report describes the preparation of ten specimens to be used for the study of the effect of swelling on the propagation of irradiation assisted stress corrosion cracking cracks. Four compact tension specimens, four microscopy plates and two tensile specimens were machined from a AISI 304 material that was irradiated up to 33 dpa. The specimens had been machined such as to represent the behavior of materials with 3.7%swelling and <2% swelling.

  20. Swelling of Clay-Sulfate Rocks: A Review of Processes and Controls

    NASA Astrophysics Data System (ADS)

    Butscher, Christoph; Mutschler, Thomas; Blum, Philipp

    2016-04-01

    The swelling of clay-sulfate rocks is a major threat in tunnel engineering, causing serious damage to tunnels and producing high additional costs during tunnel construction and operation. The swelling problem is also known from other geotechnical fields, such as road and bridge construction, and in conjunction with geothermal drillings. The planning of counter measures that would stop or minimize the swelling is extremely difficult, and it is currently impossible to predict the swelling behavior of an actual geotechnical project. One of the reasons is our limited knowledge of the processes involved in the swelling of clay-sulfate rocks, and of the geological, mineralogical, chemical, hydraulic and mechanical controls of the swelling. This article presents a literature review of processes in swelling clay-sulfate rocks and associated controls. Numerical models that aim at simulating the processes and controls are also included in this review, and some of the remaining open questions are pointed out. By focusing on process-related work in this review, the article intends to stimulate further research across disciplines in the field of swelling clay-sulfate rocks to finally get a step further in managing the swelling problem in geotechnical projects.

  1. An extremely rare case of metastatic retinoblastoma of parotids presenting as a massive swelling in a child.

    PubMed

    Purkayastha, Abhishek; Sharma, Neelam; Pathak, Abhishek; Kapur, Bhupendra Nath; Dutta, Vibha

    2016-04-01

    Retinoblastoma (Rb) is a common childhood malignancy but bilateral Rb with metastasis to parotids is very uncommon. To the best of our knowledge, bilateral Rb metastasizing to parotids is very rare and this is the fifth such case reported in world literature till date in a 2-year-old male child who underwent exenteration of left eye for bilateral Rb and later developed recurrent metastasis to left parotid requiring parotidectomy. A year later he presented again with swelling left parotid region extending from occipital region reaching upto left anterior chest wall with intra-cranial extension on magnetic resonance imaging. Histopathological examination of the parotid swelling and immunohistochemistry showed metastasis from Rb. He was treated with chemotherapy followed by radiotherapy to local site and brain to which he responded well. Presently on regular follow up without any signs of locoregional and distal metastasis. Till date different types of primary parotid tumors have been reported in literature but a metastatic parotid tumor is extremely rare and therefore this case is being reported to highlight the extreme rarity, the diagnostic and therapeutic challenges, the highly aggressive nature and overall dismal prognosis of this disease entity. PMID:27186527

  2. The swelling of nitrile rubber by selected species in a synthetic jet turbine fuel

    NASA Astrophysics Data System (ADS)

    Graham, John Lynn

    The swelling of nitrile O-ring seals in petroleum distillate fuels has long been attributed to the aromatic species in these fuels. This presents a problem for synthetic fuels as they typically do not contain these aromatic species and thus may cause O-ring seals to shrink and fail. The composition of petroleum distillate fuels is extremely complex and it is not clear whether the swelling property originates from the aromatics in general, or if certain aromatics contribute more swelling character than others. Consequently, developing a general description of an efficient swelling promoter for O-rings in liquid hydrocarbon fuels will allow an unambiguous selection of candidate swelling agents for synthetic fuels. To accomplish this, a study was undertaken of the swelling of nitrile rubber (the most widely used O-ring material) in JP-5 (the jet propulsion fuel used by the U.S. Navy) and its synthetic equivalent S-5. Briefly, examining the molecular structure of nitrile rubber showed the fuel resistance of this polymer resides in the polar character of the cyano group suggesting that polar species in general, and hydrogen-bonded species in particular, should serve as efficient swelling promoters. A thorough test program utilizing a unique optical dilatometry method to provide temporal volume swell data, a GC-MS method for measuring the polymer/fuel partitioning, and a spectroscopic examination of thin nitrile rubber films confirmed this hypothesis. This program also showed that swelling character increases with decreasing molar volume which is consistent with previous work and general theories of solubility. Overall, this study showed that the most efficient aromatic swelling promoters for nitrile rubber are naphthalenes and asymmetrically substituted alkyl benzenes. However, polar species such as ketones and alcohols can be more efficient than aromatics while phenols and aromatic alcohols represent the most efficient potential swelling promoters for nitrile rubber in

  3. Can fertility signals lead to quality signals? Insights from the evolution of primate sexual swellings.

    PubMed

    Huchard, Elise; Courtiol, Alexandre; Benavides, Julio A; Knapp, Leslie A; Raymond, Michel; Cowlishaw, Guy

    2009-05-22

    The sexual swellings of female primates have generated a great deal of interest in evolutionary biology. Two hypotheses recently proposed to elucidate their functional significance argue that maximal swelling size advertises either female fertility within a cycle or female quality across cycles. Published evidence favours the first hypothesis, and further indicates that larger swellings advertise higher fertility between cycles. If so, a male preference for large swellings might evolve, driving females to use swellings as quality indicators, as proposed by the second hypothesis. In this paper, we explore this possibility using a combination of empirical field data and mathematical modelling. We first test and find support for three key predictions of the female-quality hypothesis in wild chacma baboons (Papio ursinus): (i) inter-individual differences in swelling size are maintained across consecutive cycles, (ii) females in better condition have larger swellings and higher reproductive success, and (iii) males preferentially choose females with large swellings. We then develop an individual-based simulation model that indicates that females producing larger swellings can achieve higher mating success even when female-female competition is low and within-female variance in the trait is high. Taken together, our findings show that once sexual swellings have evolved as fertility signals, they might, in certain socio-sexual systems, be further selected to act as quality signals. These results, by reconciling two hypotheses, help to clarify the processes underlying sexual swelling evolution. More generally, our findings suggest that mate choice for direct benefits (fertility) can lead to indirect benefits (good genes).

  4. Roles of changes in active glutamine transport in brain edema development during hepatic encephalopathy: an emerging concept.

    PubMed

    Zielińska, Magdalena; Popek, Mariusz; Albrecht, Jan

    2014-01-01

    Excessive glutamine (Gln) synthesis in ammonia-overloaded astrocytes contributes to astrocytic swelling and brain edema, the major complication of hepatic encephalopathy (HE). Much of the newly formed Gln is believed to enter mitochondria, where it is recycled to ammonia, which causes mitochondrial dysfunction (a "Trojan horse" mode of action). A portion of Gln may increase osmotic pressure in astrocytes and the interstitial space, directly and independently contributing to brain tissue swelling. Here we discuss the possibility that altered functioning of Gln transport proteins located in the cellular or mitochondrial membranes, modulates the effects of increased Gln synthesis. Accumulation of excess Gln in mitochondria involves a carrier-mediated transport which is activated by ammonia. Studies on the expression of the cell membrane N-system transporters SN1 (SNAT3) and SN2 (SNAT5), which mediate Gln efflux from astrocytes rendered HE model-dependent effects. HE lowered the expression of SN1 at the RNA and protein level in the cerebral cortex (cc) in the thioacetamide (TAA) model of HE and the effect paralleled induction of cerebral cortical edema. Neither SN1 nor SN2 expression was affected by simple hyperammonemia, which produces no cc edema. TAA-induced HE is also associated with decreased expression of mRNA coding for the system A carriers SAT1 and SAT2, which stimulate Gln influx to neurons. Taken together, changes in the expression of Gln transporters during HE appear to favor retention of Gln in astrocytes and/or the interstitial space of the brain. HE may also affect arginine (Arg)/Gln exchange across the astrocytic cell membrane due to changes in the expression of the hybrid Arg/Gln transporter y(+)LAT2. Gln export from brain across the blood-brain barrier may be stimulated by HE via its increased exchange with peripheral tryptophan. PMID:24072671

  5. Non-monotonic swelling of surface grafted hydrogels induced by pH and/or salt concentration

    NASA Astrophysics Data System (ADS)

    Longo, Gabriel S.; Olvera de la Cruz, Monica; Szleifer, I.

    2014-09-01

    We use a molecular theory to study the thermodynamics of a weak-polyacid hydrogel film that is chemically grafted to a solid surface. We investigate the response of the material to changes in the pH and salt concentration of the buffer solution. Our results show that the pH-triggered swelling of the hydrogel film has a non-monotonic dependence on the acidity of the bath solution. At most salt concentrations, the thickness of the hydrogel film presents a maximum when the pH of the solution is increased from acidic values. The quantitative details of such swelling behavior, which is not observed when the film is physically deposited on the surface, depend on the molecular architecture of the polymer network. This swelling-deswelling transition is the consequence of the complex interplay between the chemical free energy (acid-base equilibrium), the electrostatic repulsions between charged monomers, which are both modulated by the absorption of ions, and the ability of the polymer network to regulate charge and control its volume (molecular organization). In the absence of such competition, for example, for high salt concentrations, the film swells monotonically with increasing pH. A deswelling-swelling transition is similarly predicted as a function of the salt concentration at intermediate pH values. This reentrant behavior, which is due to the coupling between charge regulation and the two opposing effects triggered by salt concentration (screening electrostatic interactions and charging/discharging the acid groups), is similar to that found in end-grafted weak polyelectrolyte layers. Understanding how to control the response of the material to different stimuli, in terms of its molecular structure and local chemical composition, can help the targeted design of applications with extended functionality. We describe the response of the material to an applied pressure and an electric potential. We present profiles that outline the local chemical composition of the

  6. Adsorption-induced coal swelling and stress: Implications for methane production and acid gas sequestration into coal seams

    NASA Astrophysics Data System (ADS)

    Cui, Xiaojun; Bustin, R. Marc; Chikatamarla, Laxmi

    2007-10-01

    Sequestration of CO2 and H2S into deep unminable coal seams is an attractive option to reduce their emission into atmosphere and at the same time displace preadsorbed CH4 which is a clean energy resource. High coal seam permeability is required for efficient and practical sequestration of CO2 and H2S and recovery of CH4. However, adsorption of CO2 and H2S into coals induces strong swelling of the coal matrix (volumetric strain) and thus reduces significantly coal permeability by narrowing and even closing fracture apertures. Our experimental data on three western Canadian coals show that the adsorption-induced volumetric strain is approximately linearly proportional to the volume of adsorbed gas, and for the same gas, different coals have very similar volumetric strain coefficient. Impacts of adsorption-induced swelling on stress and permeability around wellbores were analytically investigated using our developed stress and permeability models. Our model results indicate that adsorption-induced volumetric strain has significant controls on stress and permeability of producing and sequestrating coal seams and consequently the potential of acid gas sequestration. Coal seams may undergo >10 times enhancement of permeability around CH4-producing wellbores due to a reduction in effective stress as a result of coal shrinking caused by methane desorption accompanying a reduction in reservoir pressure. Injection of H2S and CO2 on the other hand results in strong sorption-induced swelling and a marked increase in effective stress which in turn leads to a reduction of coal seam permeability of up to several orders of magnitude. Injection of mixtures of N2 and CO2 such as found in flue gas results in weaker swelling, the amount of which varies with gas composition, and provides the greatest opportunity of sequestering CO2 and secondary recovery of CH4 for most coals. Because of the marked swelling of coal in the presence of H2S, even minor amounts of H2S result in a marked

  7. Non-monotonic swelling of surface grafted hydrogels induced by pH and/or salt concentration

    SciTech Connect

    Longo, Gabriel S.; Olvera de la Cruz, Monica; Szleifer, I.

    2014-09-28

    We use a molecular theory to study the thermodynamics of a weak-polyacid hydrogel film that is chemically grafted to a solid surface. We investigate the response of the material to changes in the pH and salt concentration of the buffer solution. Our results show that the pH-triggered swelling of the hydrogel film has a non-monotonic dependence on the acidity of the bath solution. At most salt concentrations, the thickness of the hydrogel film presents a maximum when the pH of the solution is increased from acidic values. The quantitative details of such swelling behavior, which is not observed when the film is physically deposited on the surface, depend on the molecular architecture of the polymer network. This swelling-deswelling transition is the consequence of the complex interplay between the chemical free energy (acid-base equilibrium), the electrostatic repulsions between charged monomers, which are both modulated by the absorption of ions, and the ability of the polymer network to regulate charge and control its volume (molecular organization). In the absence of such competition, for example, for high salt concentrations, the film swells monotonically with increasing pH. A deswelling-swelling transition is similarly predicted as a function of the salt concentration at intermediate pH values. This reentrant behavior, which is due to the coupling between charge regulation and the two opposing effects triggered by salt concentration (screening electrostatic interactions and charging/discharging the acid groups), is similar to that found in end-grafted weak polyelectrolyte layers. Understanding how to control the response of the material to different stimuli, in terms of its molecular structure and local chemical composition, can help the targeted design of applications with extended functionality. We describe the response of the material to an applied pressure and an electric potential. We present profiles that outline the local chemical composition of the

  8. Brain Tumors

    MedlinePlus

    A brain tumor is a growth of abnormal cells in the tissues of the brain. Brain tumors can be benign, with no cancer cells, ... cancer cells that grow quickly. Some are primary brain tumors, which start in the brain. Others are ...

  9. Reversible Swelling of Chitosan and Quaternary Ammonium Modified Chitosan Brush Layers: Effect of pH and Counter Anion Size and Functionality.

    PubMed

    Lee, Hyun-Su; Yee, Michael Q; Eckmann, Yonaton Y; Hickok, Noreen J; Eckmann, David M; Composto, Russell J

    2012-10-01

    This study investigates the swelling of grafted polycationic brushes as a function of pH and anion type. The brushes are chitosan (CH) and chitosans with 27% and 51% degree of substitution (DS) of quaternary ammonium salt, denoted as CH-Q(25) and CH-Q(50), respectively. The water content and swelling behaviors are monitored using in situ quartz-crystal microbalance with dissipation (QCM-D). The pH varies from ~3.5 to 8.5, and the counter anion types include chloride, acetate, and citrate. At fixed pH, the water content and brush swelling increase as the DS increases. Whereas the CH-Q(50) brush layer shows symmetric swelling with a minimum near pH = 4.5, the swelling of CH and CH-Q(25) is relatively constant as pH decreases from 8.2 to 5.5, and then begins to increase near pH 4. These studies indicate that the symmetric swelling of CH-Q(50) is likely attributed to increasing protonation of primary amines for pH values below pH 6.5 and the quaternary ammonium salts above pH 6.5. At pH 4, the swelling of the CH brush increases upon exchanging the smaller chloridewith a bulkier acetate anion, which is less effective at screening intra/inter molecular repulsion. In contrast, upon exchanging the acetate with trifunctional citrate, CH and CH-Q(25) brushes collapse by 53 and 42%, respectively, because the citrate forms ionic cross-links. To test antibacterial properties, silicon oxide, CH and CH-Q(50) brush layers are exposed to 10(7)-10(8) cfu/ml of S. aureus for two days at 37 °C and exposed to stepped shear stresses in 2 min intervals. Whereas an S. aureus biofilm adheres strongly to silicon oxide and CH for stresses up to 12 dyne/cm(2), biofilms on CH-Q(50) detach at a relatively low shear stress, 1.5 dyne/cm(2). Due to their high degree of swelling that can be tuned via pH, counterion size and type, chitosan and quaternary modified chitosans have potential as responsive coatings for applications including MEMS/NEMS devices and drug eluting implants. PMID:23209343

  10. Swelling-shrinkage measurements of bentonite using coupled environmental scanning electron microscopy and digital image analysis.

    PubMed

    Montes-H, G

    2005-04-01

    The swelling clays have been proposed as engineered barriers in geological disposal systems for waste because these materials are assumed to build a better impermeable zone around wastes by swelling. However, the swelling potential of soils is also considered a prevalent cause of damage to buildings and constructions. For these reasons, it is fundamental to investigate the physicochemical and mechanical behavior of swelling clays. In the current study, the swelling-shrinkage potential (aggregates scale) was estimated using an environmental scanning electron microscope (ESEM) coupled with a digital image analysis (DIA) program (Visilog). In fact, the isolated aggregates of raw and cation-exchanged bentonite were directly observed at different relative humidities in an ESEM chamber. Then the "Visilog" software was used to estimate the percent augmentation of the aggregate surface as a function of time and as a function of relative humidity. This estimation allows for the calculation of the swelling-shrinkage potential (%) of bentonite. Finally, a kinetic model of first order was tested to fit the kinetic experimental data of swelling-shrinkage potential. The results show that ESEM-DIA coupling can be a powerful method of estimating the swelling-shrinkage potential of expansive clays. In addition, the exponential models fit well with the kinetic experimental data. PMID:15752813

  11. Polymerization of alanine in the presence of a non-swelling montmorillonite

    NASA Technical Reports Server (NTRS)

    Paecht-Horowitz, M.; Lahav, N.

    1977-01-01

    Alanine, starting from alanine-adenylate, has been polymerized in the presence of non-swelling Al-montmorillonite. The yield of polymerization is much lower than that obtained in the presence of swelling Na-montmorillonite. The possibility that the changing interlayer spacing in Na-montmorillonite might be responsible for its catalytic properties, is discussed.

  12. [Applicability of a natural swelling matrix as the propellant of osmotic pump tablets].

    PubMed

    Wu, Li; Li, Hai-Yan; Yin, Xian-Zhen; Li, Ying; Chen, Jian-Xiu; Hu, Rong-feng; Zhang, Ji-Wen

    2013-08-01

    The purpose of this study is to investigate the applicability of a natural swelling matrix derived from boat-fruited sterculia seed (SMS) as the propellant of osmotic pump tablets. The sugar components, static swelling, water uptake and viscosity of SMS were determined and compared with that of polythylene oxide (WSR-N10 and WSR-303). Both ribavirin and glipizide were used as water-soluble and water-insoluble model drugs. Then, the monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide were prepared using SMS as the osmotically active substance and propellant. SMS was mainly composed of rhamnose, arabinose, xylose and galactose and exhibited relatively high swelling ability. The area of the disintegrated matrix tablet was 20.1 times as that at initial after swelling for 600 s. SMS swelled rapidly and was fully swelled (0.5%) in aqueous solution with relative low viscosity (3.66 +/- 0.03) mPa x s at 25 degrees C. The monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide using SMS as propellant exhibited typical drug release features of osmotic pumps. In conclusion, the swelling matrix derived from boat-fruited sterculia seed, with low viscosity and high swelling, is a potential propellant in the application of osmotic pump tablets.

  13. A mechanism of swelling suppression in phosphorous-modified Fe-Ni-Cr alloys*1

    NASA Astrophysics Data System (ADS)

    Lee, E. H.; Mansur, L. K.

    1986-11-01

    Five simple alloys were ion irradiated at 948 K in an experiment designed to investigate the mechanism of swelling suppression associated wtih phosphorous additions. One of the alloys was the simple ternary Fe-15Ni-13Cr, another had 0.05% P added and the other three had further additions of the phosphide precipitate-forming elements Ti and/or Si. Ion irradiations were carried out with heavy ions only (Ni or Fe) or with heavy ions followed by dual heavy ions and helium. The ternary with and without P swelled readily early in dose with or without helium. The other three alloys only showed swelling in the presence of helium and exhibited a long delay in dose prior to the onset of swelling. These displayed fine distributions of Fe 2P type phosphide precipitates enhanced by irradiation. The phosphide particles gave rise to very high concentrations of stable helium filled cavities at the precipitate matrix interfaces. The results were analyzed in terms of the theory of cavity swelling. The accumulation of the critical number of gas atoms in an individual cavity is required in the theory for point defect driven swelling to begin. It is concluded that the primary mechanism leading to swelling suppression is therefore the dilution of injected helium over a very large number of cavities. It is suggested that this mechanism may offer a key for alloy design for swelling resistance in high helium environments.

  14. Swelling of whey and egg white protein hydrogels with stranded and particulate microstructures.

    PubMed

    Li, Hui; Zhao, Lei; Chen, Xiao Dong; Mercadé-Prieto, Ruben

    2016-02-01

    Swelling of protein hydrogels in alkaline conditions strongly depends on the gel microstructure. Stranded transparent gels swell as predicted using a modified Flory-Rehner model with the net protein charge. Particulate opaque gels swell very differently, with a sudden increase at a narrow pH range. Its swelling is not controlled by the protein charge, but by the destruction of the non-covalent interactions. Comparable dissolution thresholds, one with pH and another with the degree of swelling, are observed in both types of microstructures. These conclusions are valid for both whey protein isolate (WPI) gels and egg white gels, suggesting that they are universal for all globular proteins that can form such microscructures. Differences are observed, however, from the prevalent chemical crosslinks in each protein system. Non-covalent interactions dominate WPI gels; when such interactions are destroyed at pH≥11.5 the gels swell extensively and eventually dissolve. In egg white gels, the higher degree of disulphide crosslinking allows extensive swelling when non-covalent interactions are destroyed, but dissolution only occurs at pH≥13 when covalent crosslinks are cleaved. The current study highlights that the microstructure of protein hydrogels, a unique particularity of protein systems compared to other synthetic hydrogels, defines swelling.

  15. Interaction between Sorption of Organic Compounds, Clay Swelling, and Cation Exchange Selectivity in Smectites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Smectites are the most commonly found mineral in temperate region soils. Smectites exhibit variability in shrink–swell behavior and sorption of organic molecules. Previous research has established the inter-relation between extent of swelling and sorption of organic compounds by smectites. The effec...

  16. Slow growing, painful, nodular swelling on the buccal mucosa: a case report.

    PubMed

    Austin, Ravi David; Mathew, Philips; Rajathi, Maria J; Murugan, Kandasamy

    2014-01-01

    Nodular swellings of the oral cavity are frequently encountered in dental practice. The disease processes that give rise to nodular swellings in the oral cavity include inflammatory hyperplasias, obstructive minor salivary gland disorders, infections, benign connective tissue neoplasms and salivary gland neoplasms. Understandably, the nature of these entities also varies significantly, ranging from very innocuous to aggressive lesions, underscoring the need for accurate diagnosis.

  17. Anisotropic swelling behavior of hot-extruded beryllium

    NASA Astrophysics Data System (ADS)

    Kang, Suk Hoon; Jang, Jinsung; Kim, Tae Kyu; Jung, Myung Hwan; Lee, Jae Sang

    2016-04-01

    The lifetime of beryllium reflector assemblies is usually determined by neutron irradiation induced swelling, which results in mechanical interferences or fractures of the beryllium elements. Therefore, the dimensional stability and microstructure variations of beryllium during irradiation are important issues to study. In this paper, the microstructure characteristics of S-200-F and EHP-56 beryllium blocks, which were manufactured by using vacuum hot pressing (VHP) and hot extrusion (HE), respectively, were investigated. BeO distributions, grain shapes, and preferred orientations were investigated by using SEM-EPMA and SEM-EBSD systems. Dissimilarly to S-200-F, a strong fiber texture developed in the EHP-56 during the HE process; the basal planes in the majority of grains were arranged along the extrusion direction. To emulate the microstructure evolution during neutron irradiation, we irradiated the electro-polished surface of EHP-56 with protons at room temperature, where the acceleration voltage and the number of protons were 120 keV and 2.0 × 1018 ions/cm2, respectively. Irradiation-induced cavities were observed to be considerably longer along the basal plane in the EHP-56 specimen. Correspondingly, the amount of dimensional change was smaller along the direction parallel to the basal plane.

  18. Mechanical and swelling behaviour of well characterized polybutadiene networks

    NASA Technical Reports Server (NTRS)

    Mckenna, Gregory B.; Hinkley, Jeffrey A.

    1986-01-01

    Endlinking of hydroxyl-terminated polybutadiene with the appropriate isocyanate has been used to prepare well characterized networks. Two networks have been studied with molecular weights of the prepolymers being 6100 and 2400 g/mole by g.p.c. Cylindrical specimens were prepared and the derivatives of the stored energy function with respect to the stretch invariants were determined by torque and normal force measurements in torsion. From these data the Valanis-Landel (1967) stored energy function derivatives w-prime(lambda) were determined for both networks. The stored energy function for the junction constraint model of Flory (1953, 1977, 1979, 1985) which is a special form of the Valanis-Landel function, has been fitted to that determined from the experiments. The contributions to the stored energy function from the phantom network and from the junction constraints respectively do not agree with predictions from the topologies of the networks. In spite of this, the form of w-prime(lambda) for the junction constraint model gives an excellent 'curve fit' to the data. Comparison is also made with equilibrium swelling.

  19. Increased Hydrogel Swelling Induced by Absorption of Small Molecules.

    PubMed

    Nam, Changwoo; Zimudzi, Tawanda J; Geise, Geoffrey M; Hickner, Michael A

    2016-06-01

    The water and small molecule uptake behavior of amphiphilic diacrylate terminated poly(dimethylsiloxane) (PDMSDA)/poly(ethylene glycol diacrylate) (PEGDA) cross-linked hydrogels were studied using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. These hydrogel networks absorbed more water as the PEGDA content of the network increased. In contrast to typical osmotic deswelling behavior that occurs when liquid water equilibrated hydrogels are immersed in small molecule solutions with water activities less than unity, water-swollen gels immersed in 2-acrylamido-2-methylpropanesulfonic acid (AMPS-H) solutions rapidly regained their water content within 4 min following an initial deswelling response. In situ ATR-FTIR analysis of the hydrogel film during the dynamic swelling experiment indicated that small molecule absorption into the gel played an important role in inducing gel reswelling in low water activity solutions. This aspect of polymer gel water uptake and interaction with small molecules is important for optimizing hydrogel coatings and hydrophilic polymer applications where there is an interaction between the internal chemical structure of the gel and electrolytes or other molecules in solution. PMID:27159118

  20. Specific Effects of Fiber Size and Fiber Swelling on Biomass Substrate Surface Area and Enzymatic Digestibility

    SciTech Connect

    Ju, Xiaohui; Grego, Courtnee; Zhang, Xiao

    2013-09-01

    To clarify the specific effect of biomass substrate surface area on its enzymatic digestibility, factors of fiber size reduction and swelling changes were investigated by using poplar substrates with controlled morphological and chemical properties after modified chemical pulping. Results showed that fiber size changes had insignificant influence on enzymatic hydrolysis, although the external surface area increased up to 41% with the reduction of fiber size. Swelling changes caused by increased biomass fiber porosities after PFI refining showed a significant influence on the efficiency of enzymatic hydrolysis. It is also found that chemical properties such as xylan and lignin content can influence the swelling effect. Xylan is confirmed to facilitate substrate hydrolysability by swelling, while lignin restricts swelling effect and thus minimizes the enzyme accessibility to substrates.

  1. Influence of layer charge and charge location on the swelling pressure of dioctahedral smectites

    NASA Astrophysics Data System (ADS)

    Sun, Linlin; Ling, Chian Ye; Lavikainen, Lasse P.; Hirvi, Janne T.; Kasa, Seppo; Pakkanen, Tapani A.

    2016-07-01

    Swelling pressure of dioctahedral smectites in the montmorillonite - beidellite series was investigated by molecular dynamics simulations. The pressure was found to correlate inversely with the magnitude of the layer charge in the range of -0.5 to -1.0 per unit cell. The beidellite type smectites were found to have lower swelling pressure than the montmorillonite type smectites. A clear effect of the type of interlayer cations on the swelling pressure was found. The sodium smectites sustained significant pressure even at longer interlayer distances, while in calcium smectites the pressure decreased soon after the initial swelling. The simulation results are in good agreement with experimental observations and provide a tool for predicting macroscopic swelling behavior in smectites.

  2. Modelling of Swelling by the Fluorescence Technique in Kappa Carrageenan Gels

    NASA Astrophysics Data System (ADS)

    Tari, Ozlem; Pekcan, Onder

    2011-12-01

    Kappa (-κ) carrageenan gels prepared with various carrageenan concentrations in pure water were completely dried and then swelled in water vapor. Steady state fluorescence measurements were performed using a spectrometer equipped with temperature controller. Pyranine was embedded in κ-carrageenan gels as a fluorescence probe during gel preparation. The fluorescence intensity, I, increased exponentially as swelling time is increased for all gel samples. The increase in I was modelled using Li-Tanaka equation from which swelling time constants, τc and cooperative diffusion coefficients, Dc were determined. It was observed that Dc increased as the swelling temperature was increased. On the other hand at each temperature, it was seen that Dc decreased as kappa carrageenan concentration was increased. Activation energies for swelling were obtained and found to be 57.4, 58.3 and 62.73 kJ mol-1 for the gels with increasing amount of κ-carrageenan content.

  3. Brain surgery

    MedlinePlus

    Craniotomy; Surgery - brain; Neurosurgery; Craniectomy; Stereotactic craniotomy; Stereotactic brain biopsy; Endoscopic craniotomy ... cut depends on where the problem in the brain is located. The surgeon creates a hole in ...

  4. Brain Malformations

    MedlinePlus

    Most brain malformations begin long before a baby is born. Something damages the developing nervous system or causes it ... medicines, infections, or radiation during pregnancy interferes with brain development. Parts of the brain may be missing, ...

  5. Inversion of swell frequency from a 1-year HF radar dataset collected in Brittany (France)

    NASA Astrophysics Data System (ADS)

    Wang, Weili; Forget, Philippe; Guan, Changlong

    2014-10-01

    This article presents long period ocean wave (swell) frequencies inverted from a 13-month dataset of high-frequency (HF) phased array radars and an assessment of these estimates by comparison with WAVEWATCH III model data. The method of swell frequency inversion from high-frequency radar sea echo Doppler spectra is described. Radar data were collected from a two-site HF Wellen Radar (WERA) radar system on the west coast of Brittany (France) operating at 12 MHz. A standard beam-forming processing technique has been used to obtain Doppler spectra of processed radar cells. Swell frequencies are obtained from the frequencies of particular spectral peaks of the second-order continuum in hourly averaged Doppler spectra. The data coverage of effective Doppler spectra considered for swell frequency estimates shows the influence of islands and shallow water effects. Swell estimates from both radar stations are in good agreement. The comparison of radar-derived results to WAVEWATCH III (WW3) estimates shows that radar measurements agree quite well with model results. The bias and standard deviation between two estimates are very small for swells with frequency less than 0.09 Hz (period >11 s), whereas radar estimates are generally lower than model estimates for shorter swells, along with higher standard deviation. Statistical analysis suggests that radar measurement uncertainty explains most of the difference between radar and model estimates. For each swell event, time series of frequency exhibits a quasi-linear frequency increase which is associated with the dispersive property of wave phase velocity. The use of swell frequency estimates from both radars on common radar cells only slightly increases the accuracy of swell frequency measurement.

  6. Antisense oligodeoxynucleotide inhibition of a swelling-activated cation channel in osteoblast-like osteosarcoma cells

    NASA Technical Reports Server (NTRS)

    Duncan, R. L.; Kizer, N.; Barry, E. L.; Friedman, P. A.; Hruska, K. A.

    1996-01-01

    By patch-clamp analysis, we have shown that chronic, intermittent mechanical strain (CMS) increases the activity of stretch-activated cation channels of osteoblast-like UMR-106.01 cells. CMS also produces a swelling-activated whole-cell conductance (Gm) regulated by varying strain levels. We questioned whether the swelling-activated conductance was produced by stretch-activated cation channel activity. We have identified a gene involved in the increase in conductance by using antisense oligodeoxynucleotides (ODN) derived from the alpha 1-subunit genes of calcium channels found in UMR-106.01 cells (alpha1S, alpha1C, and alpha1D). We demonstrate that alpha 1C antisense ODNs abolish the increase in Gm in response to hypotonic swelling following CMS. Antisense ODNs to alpha1S and alpha1D, sense ODNs to alpha1C, and sham permeabilization had no effect on the conductance increase. In addition, during cell-attached patch-clamp studies, antisense ODNs to alpha1c completely blocked the swelling-activated and stretch-activated nonselective cation channel response to strain. Antisense ODNs to alpha1S treatment produced no effect on either swelling-activated or stretch-activated cation channel activity. There were differences in the stretch-activated and swelling-activated cation channel activity, but whether they represent different channels could not be determined from our data. Our data indicate that the alpha1C gene product is involved in the Gm and the activation of the swelling-activated cation channels induced by CMS. The possibility that swelling-activated cation channel genes are members of the calcium channel superfamily exists, but if alpha1c is not the swelling-activated cation channel itself, then its expression is required for induction of swelling-activated cation channel activity by CMS.

  7. Monitoring austral and cyclonic swells in the "Iles Eparses" (Mozambique channel) from microseismic noise

    NASA Astrophysics Data System (ADS)

    Barruol, Guilhem; Davy, Céline; Fontaine, Fabrice R.; Schlindwein, V.; Sigloch, K.

    2016-04-01

    We deployed five broadband three-components seismic stations in the Iles Eparses in the south-west Indian Ocean and on Mayotte Island, between April 2011 and January 2014. These small and remote oceanic islands suffer the effects of strong ocean swells that affect their coastal environments but most islands are not instrumented by wave gauges to characterize the swells. However, wave action on the coast causes high levels of ground vibrations in the solid earth, so-called microseismic noise. We use this link between the solid earth and ocean wave activity to quantify the swells locally. Spectral analyses of the continuous seismic data show clear peaks in the 0.05-0.10 Hz frequency band (periods between 10 and 20 s), corresponding to the ocean wave periods of the local swells. We analyze an example of austral swell occurring in August 2013 and a cyclonic event (Felleng) that developed in January 2013, and quantify the ground motion at each station induced by these events. In both cases, we find a linear polarization in the horizontal plane with microseismic amplitude directly correlated to the swell height (as predicted by the global swell model WaveWatchIII), and a direction of polarization close to the predicted swell propagation direction. Although this analysis has not been performed in real time, it demonstrates that terrestrial seismic stations can be efficiently used as wave gauges, and are particularly well suited for quantifying extreme swell events. This approach may therefore provide useful and cheaper alternatives to wave buoys for monitoring swells and the related environmental processes such as beach erosion or coral reef damages.

  8. Bowers Swell: Evidence for a zone of compressive deformation concentric with Bowers Ridge, Bering Sea

    USGS Publications Warehouse

    Marlow, M. S.; Cooper, A. K.; Dadisman, S.V.; Geist, E.L.; Carlson, P.R.

    1990-01-01

    Bowers Swell is a newly discovered bathymetric feature which is up to 90 m high, between 12 and 20 km wide, and which extends arcuately about 400 km along the northern and eastern sides of Bowers Ridge. The swell was first revealed on GLORIA sonographs and subsequently mapped on seismic reflection and 3.5 kHz bathymetric profiles. These geophysical data show that the swell caps an arcuate anticlinal ridge, which is composed of deformed strata in an ancient trench on the northern and eastern sides of Bowers Ridge. The trench fill beneath the swell is actively deforming, as shown by faulting of the sea floor and by thinning of the strata across the crest of the swell. Thinning and faulting of the trench strata preclude an origin for the swell by simple sediment draping over an older basement high. We considered several models for the origin of Bowers Swell, including folding and uplift of the underlying trench sediment during the interaction between the Pacific plate beneath the Aleutian Ridge and a remnant oceanic slab beneath Bowers Ridge. However, such plate motions should generate extensive seismicity beneath Bowers Ridge, which is aseismic, and refraction data do not show any remnant slab beneath Bowers Ridge. Another origin considered for Bowers Swell invokes sediment deformation resulting from differential loading and diapirism in the trench fill. However, diapirism is not evident on seismic reflection profiles across the swell. We favour a model in which sediment deformation and swell formation resulted from a few tens of kilometers of low seismicity motion by intraplate crustal blocks beneath the Aleutian Basin. This motion may result from the translation of blocks in western Alaska to the south-west, forcing the movement of the Bering Sea margin west of Alaska into the abyssal Aleutian Basin. ?? 1990.

  9. Shrinking and swelling clays under droughts: measurements at the Mormoiron test-site and first analyses (Vaucluse, South-East of France)

    NASA Astrophysics Data System (ADS)

    Gourdier, Sébastien; Vandromme, Rosalie; Grandjean, Gilles

    2013-04-01

    In France, exceptional periods of rainfall deficit (1976, 1989 to 1991 and 1996 to 1997) have caused damages to houses due to their vulnerability to shrinking and swelling clays phenomenon. Between 1998 and 2010, BRGM has been producing a national hazard map related to shrinking and swelling clays, built by crossing geological data and information on density of damages for each geological formation (methodology developed since 1995). The intense drought of summer 2003 has pointed out the necessity of a better understanding of this phenomenon. At the request of the French Ministry of Environment, BRGM has developed a new method for measuring the moisture evolution with depth in order to study its impact on the swelling capacity of clayed soil. The site of Mormoiron (Vaucluse, South-East of France) has then been instrumented for that purpose, with moisture sensors (since December 2004) and extensometers (since March 2009) at different depths. These data have been used to test and improve existing empirical models which are supposed to assess settlements and swellings, depending on the soil water content. Compilations of different measurements have shown, after basic processing made on the data (filtering, resampling, etc.), evident correlations between rain and surface displacements. The model finally obtained gives quite good dependence between these two quantities for the uppermost soil layers (0.2m and 0.5m). More research are being undertaken to physically explain this relationship, particularly for deeper layers. These results should lead to propose a calibrated model for predicting soil deformations from climatic data.

  10. Erratum for: Master equation and Fokker-Planck methods for void nucleation and growth in irradiation swelling, Vacancy cluster evolution and swelling in irradiated 316 stainless steel and Radiation swelling behavior and its dependence on temperature, dose

    SciTech Connect

    Surh, M P; Sturgeon, J B; Wolfer, W G

    2005-01-03

    We have recently discovered an error in our void nucleation code used in three prior publications [1-3]. A term was omitted in the model for vacancy re-emission that (especially at high temperature) affects void nucleation and growth during irradiation as well as void annealing and Ostwald ripening of the size distribution after irradiation. The omission was not immediately detected because the calculations predict reasonable void densities and swelling behaviors when compared to experiment at low irradiation temperatures, where void swelling is prominent. (Comparable neutron irradiation experiments are less prevalent at higher temperatures, e.g., > 500 C.)

  11. Assessment of void swelling in austenitic stainless steel PWR core internals.

    SciTech Connect

    Chung, H. M.; Energy Technology

    2006-01-31

    As many pressurized water reactors (PWRs) age and life extension of the aged plants is considered, void swelling behavior of austenitic stainless steel (SS) core internals has become the subject of increasing attention. In this report, the available database on void swelling and density change of austenitic SSs was critically reviewed. Irradiation conditions, test procedures, and microstructural characteristics were carefully examined, and key factors that are important to determine the relevance of the database to PWR conditions were evaluated. Most swelling data were obtained from steels irradiated in fast breeder reactors at temperatures >385 C and at dose rates that are orders of magnitude higher than PWR dose rates. Even for a given irradiation temperature and given steel, the integral effects of dose and dose rate on void swelling should not be separated. It is incorrect to extrapolate swelling data on the basis of 'progressive compounded multiplication' of separate effects of factors such as dose, dose rate, temperature, steel composition, and fabrication procedure. Therefore, the fast reactor data should not be extrapolated to determine credible void swelling behavior for PWR end-of-life (EOL) or life-extension conditions. Although the void swelling data extracted from fast reactor studies is extensive and conclusive, only limited amounts of swelling data and information have been obtained on microstructural characteristics from discharged PWR internals or steels irradiated at temperatures and at dose rates comparable to those of a PWR. Based on this relatively small amount of information, swelling in thin-walled tubes and baffle bolts in a PWR is not considered a concern. As additional data and relevant research becomes available, the newer results should be integrated with existing data, and the worthiness of this conclusion should continue to be scrutinized. PWR baffle reentrant corners are the most likely location to experience high swelling rates, and

  12. Matrix Shrinkage and Swelling Effects on Economics of Enhanced Coalbed Methane Production and CO2 Sequestration in Coal

    SciTech Connect

    Gorucu, F.B.; Jikich, S.A.; Bromhal, G.S.; Sams, W.N.; Ertekin, T.; Smith, D.H.

    2005-09-01

    Increases in CO2 levels in the atmosphere and their contributions to global climate change have been a major concern. It has been shown that CO2 injection can enhance the methane recovery from coal. Accordingly, sequestration costs can be partially offset by the value added product. Indeed, coal seam sequestration may be profitable, particularly with the introduction of incentives for CO2 sequestration. Hence, carbon dioxide sequestration in unmineable coals is a very attractive option, not only for environmental reasons, but also for possible economic benefits. Darcy flow through cleats is an important transport mechanism in coal. Cleat compression and permeability changes due to gas sorption desorption, changes of effective stress, and matrix swelling and shrinkage introduce a high level of complexity into the feasibility of a coal sequestration project. The economic effects of carbon dioxide-induced swelling on permeabilities and injectivities has received little (if any) detailed attention. Carbon dioxide and methane have different swelling effects on coal. In this work, the Palmer-Mansoori model for coal shrinkage and permeability increases during primary methane production was re-written to also account for coal swelling caused by carbon dioxide sorption. The generalized model was added to PSU-COALCOMP, a dual porosity reservoir simulator for primary and enhanced coalbed methane production. A standard five-spot of vertical wells and representative coal properties for Appalachian coals were used.[1] Simulations and sensitivity analyses were performed with the modified simulator for nine different parameters, including coal seam and operational parameters and economic criteria. The coal properties and operating parameters that were varied included Young’s modulus, Poisson’s ratio, the cleat porosity, and the injection pressure. The economic variables included CH4 price, CO2 cost, CO2 credit, water disposal cost, and interest rate. Net present value analyses

  13. Molecular accessibility in solvent swelled coals. Quarterly report, [September--November, 1993

    SciTech Connect

    Kispert, L.D.

    1993-11-01

    This quarter, experiments were performed on the use of binary swelling solvents in molecular accessibility in coal conversion. These experiments consisted of accessibility measurements of spin probe VII (TEMPAMINE) in Toluene swelled Illinois No. 6 APCS coal. The toluene was spiked with amounts of pyridine which ranged in concentration from 500 ppm to 10%. The experiments were done in triplicate to gain information about the experimental error involved in the procedure. It was shown that oscillations occur in the concentration of spin probe retained as the amount of pyridine that is added to the swelling solvent is increased. These oscillations decrease in intensity as the concentration of pyridine in the solvent solution is increased up to 2% pyridine (0.2mLs pyridine in 10mLs toluene). From a 2% pyridine concentration to a 5% concentration, there is no significant change in the retention of spin probe VII. An increase in retention is observed when the concentration of pyridine is increased to 6% and 7% successively, followed by a large decrease at 8% and 9% pyridine. The largest changes in spin probe retention are observed for concentrations of pyridine less than 0.5%. A three fold increase in spin probe retention is observed upon the addition of 500 ppm pyridine in the toluene swelling solvent, which indicates that small amounts of a strong swelling solvent could be used to improve molecular accessibility 91% in coals swelled in an otherwise weak swelling solvent.

  14. Episodic swell growth inferred from variable uplift of the Cape Verde hotspot islands

    USGS Publications Warehouse

    Ramalho, R.; Helffrich, G.; Cosca, M.; Vance, D.; Hoffmann, D.; Schmidt, D.N.

    2010-01-01

    On the Beagle voyage, Charles Darwin first noted the creation and subsidence of ocean islands, establishing in geology's infancy that island freeboard changes with time. Hotspot ocean islands have an obvious mechanism for freeboard change through the growth of the bathymetric anomaly, or swell, on which the islands rest. Models for swell development indicate that flexural, thermal or dynamic pressure contributions, as well as spreading of melt residue from the hotspot, can all contribute to island uplift. Here we test various models for swell development using the uplift histories for the islands of the Cape Verde hotspot, derived from isotopic dating of marine terraces and subaerial to submarine lava-flow morphologies. The island uplift histories, in conjunction with inter-island spacing, uplift rate and timing differences, rule out flexural, thermal or dynamic pressure contributions. We also find that uplift cannot be reconciled with models that advocate the spreading of melt residue in swell development unless swell growth is episodic. Instead, we infer from the uplift histories that two processes have acted to raise the islands during the past 6 Myr. During an initial phase, mantle processes acted to build the swell. Subsequently, magmatic intrusions at the island edifice caused 350 m of local uplift at the scale of individual islands. Finally, swell-wide uplift contributed a further 100 m of surface rise.

  15. Deformation mechanisms in a coal mine roadway in extremely swelling soft rock.

    PubMed

    Li, Qinghai; Shi, Weiping; Yang, Renshu

    2016-01-01

    The problem of roadway support in swelling soft rock was one of the challenging problems during mining. For most geological conditions, combinations of two or more supporting approaches could meet the requirements of most roadways; however, in extremely swelling soft rock, combined approaches even could not control large deformations. The purpose of this work was to probe the roadway deformation mechanisms in extremely swelling soft rock. Based on the main return air-way in a coal mine, deformation monitoring and geomechanical analysis were conducted, as well as plastic zone mechanical model was analysed. Results indicated that this soft rock was potentially very swelling. When the ground stress acted alone, the support strength needed in situ was not too large and combined supporting approaches could meet this requirement; however, when this potential released, the roadway would undergo permanent deformation. When the loose zone reached 3 m within surrounding rock, remote stress p ∞ and supporting stress P presented a linear relationship. Namely, the greater the swelling stress, the more difficult it would be in roadway supporting. So in this extremely swelling soft rock, a better way to control roadway deformation was to control the releasing of surrounding rock's swelling potential.

  16. Subtask 12F1: Effect of neutron irradiation on swelling of vanadium-base alloys

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Smith, D.L.

    1995-03-01

    The objective of this work is to determine the effects of neutron irradiation on the density change, void distribution, and microstructural evolution of vanadium-base alloys. Swelling behavior and microstructural evolution of V-Ti, V-Cr-Ti, and V-Ti-Si alloys were investigated after irradiation at 420-600{degrees}C up to 114 dpa. The alloys exhibited swelling maxima between 30 and 80 dpa and swelling decreased on irradiation to higher dpa. This is in contrast to the monotonically increasing swelling of binary alloys that contain Fe, Ni, Cr, Mo, W, and Si. Precipitation of dense Ti{sub 5}Si{sub 3} promotes good resistance to swelling of the Ti-containing alloys, and it was concluded that Ti of >3 wt.% and 400-1000 wppm Si are necessary to effectively suppress swelling. Swelling was minimal in V-4Cr-4Ti, identified as the most promising alloy based on good mechanical properties and superior resistance to irradiation embrittlement. 18 refs., 6 figs., 1 tab.

  17. Episodic swell growth inferred from variable uplift of the Cape Verde hotspot islands

    NASA Astrophysics Data System (ADS)

    Ramalho, R.; Helffrich, G.; Cosca, M.; Vance, D.; Hoffmann, D.; Schmidt, D. N.

    2010-11-01

    On the Beagle voyage, Charles Darwin first noted the creation and subsidence of ocean islands, establishing in geology's infancy that island freeboard changes with time. Hotspot ocean islands have an obvious mechanism for freeboard change through the growth of the bathymetric anomaly, or swell, on which the islands rest. Models for swell development indicate that flexural, thermal or dynamic pressure contributions, as well as spreading of melt residue from the hotspot, can all contribute to island uplift. Here we test various models for swell development using the uplift histories for the islands of the Cape Verde hotspot, derived from isotopic dating of marine terraces and subaerial to submarine lava-flow morphologies. The island uplift histories, in conjunction with inter-island spacing, uplift rate and timing differences, rule out flexural, thermal or dynamic pressure contributions. We also find that uplift cannot be reconciled with models that advocate the spreading of melt residue in swell development unless swell growth is episodic. Instead, we infer from the uplift histories that two processes have acted to raise the islands during the past 6Myr. During an initial phase, mantle processes acted to build the swell. Subsequently, magmatic intrusions at the island edifice caused 350m of local uplift at the scale of individual islands. Finally, swell-wide uplift contributed a further 100m of surface rise.

  18. Phenomenological force and swelling models for rechargeable lithium-ion battery cells

    NASA Astrophysics Data System (ADS)

    Oh, Ki-Yong; Epureanu, Bogdan I.; Siegel, Jason B.; Stefanopoulou, Anna G.

    2016-04-01

    Three phenomenological force and swelling models are developed to predict mechanical phenomena caused by Li-ion intercalation: a 1-D force model, a 1st order relaxation model, and a 3-D swelling model. The 1-D force model can estimate the Li-ion intercalation induced force for actual pack conditions with preloads. The model incorporates a nonlinear elastic stiffness to capture the mechanical consequences of Li-ion intercalation swelling. The model also separates the entire state of charge range into three regions considering phase transitions. The 1st order relaxation model predicts dynamic swelling during relaxation periods. A coefficient of relaxation is estimated from dynamic and quasi-static swelling at operational conditions. The 3-D swelling model predicts the swelling shape on the battery surface for all states of charge. This model introduces an equivalent modulus of elasticity, which is dependent on the state of charge, to capture material transformations of the electrodes, and the orthotropic expansion of the jellyroll in a direction perpendicular to the electrode surfaces. Considering the simplicity of the measurements and direct physical correlations between stress and strain, the proposed models can enhance battery management systems and power management strategies.

  19. Void swelling in high dose ion-irradiated reduced activation ferritic-martensitic steels

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Monterrosa, Anthony M.; Zhang, Feifei; Huang, Hao; Yan, Qingzhi; Jiao, Zhijie; Was, Gary S.; Wang, Lumin

    2015-07-01

    To determine the void swelling resistance of reduced-activation ferritic-martensitic steels CNS I and CNS II at high doses, ion irradiation was performed up to 188 dpa (4.6 × 1017 ion/cm2) at 460 °C using 5 MeV Fe++ ions. Helium was pre-implanted at levels of 10 and 100 appm at room temperature to investigate the role of helium on void swelling. Commercial FM steel T91 was also irradiated in this condition and the swelling results are of included in this paper as a reference. Voids were observed in all conditions. The 9Cr CNS I samples implanted with 10 appm helium exhibited lower swelling than 9Cr T91 irradiated at the same condition. The 12Cr CNS II with 10 and 100 appm helium showed significantly lower swelling than CNS I and T91. The swelling rate for CNS I and CNS II were determined to be 0.02%/dpa and 0.003%/dpa respectively. Increasing the helium content from 10 to 100 appm shortened the incubation region and increased the void density but had no effect on the swelling rates.

  20. Deformation mechanisms in a coal mine roadway in extremely swelling soft rock.

    PubMed

    Li, Qinghai; Shi, Weiping; Yang, Renshu

    2016-01-01

    The problem of roadway support in swelling soft rock was one of the challenging problems during mining. For most geological conditions, combinations of two or more supporting approaches could meet the requirements of most roadways; however, in extremely swelling soft rock, combined approaches even could not control large deformations. The purpose of this work was to probe the roadway deformation mechanisms in extremely swelling soft rock. Based on the main return air-way in a coal mine, deformation monitoring and geomechanical analysis were conducted, as well as plastic zone mechanical model was analysed. Results indicated that this soft rock was potentially very swelling. When the ground stress acted alone, the support strength needed in situ was not too large and combined supporting approaches could meet this requirement; however, when this potential released, the roadway would undergo permanent deformation. When the loose zone reached 3 m within surrounding rock, remote stress p ∞ and supporting stress P presented a linear relationship. Namely, the greater the swelling stress, the more difficult it would be in roadway supporting. So in this extremely swelling soft rock, a better way to control roadway deformation was to control the releasing of surrounding rock's swelling potential. PMID:27547684

  1. Depth and geoid anomalies over oceanic hotspot swells: A global survey

    SciTech Connect

    Monnereau, M.; Cazenave, A. )

    1990-09-10

    The broad depth and geoid anomalies associated with 23 hotspot swells in oceanic areas have been analyzed. Maximum height and geographical extent of the topographic swell, and of the geoid anomaly as well, have been measured for each hotspot. The results indicate a clear increase of the topographic swell height with age of the underlying lithosphere, from values in the range 300-500 m at young ages to values in the range 1,500-2,000 m at ages larger than 100 Ma. The geoid anomaly amplitude also increases with plate age from nearly zero close to mid-ocean ridges, to 6-8 m over old plates. On the other hand, the geographical extent of the swell does not show any clear relationship with plate age. The mean lateral extent of swells range from 1,000 to 1,500 km. Swells located close to spreading ridges show a significant non zero depth anomaly but are associated with negligible geoid signal. These results complete those of a previous study where the apparent compensation depth of oceanic hotspot swells was showed to increase linearly with the square root of plate age and coincide roughly with the base of the thermal lithosphere. This trend may either be interpreted in terms of lithospheric thinning or dynamical support. Besides both seem necessary to explain the observed bathymetry, in proportion evolving with aging of the lithosphere.

  2. Experimentally determined swelling pressures and geochemical interactions of compacted Wyoming bentonite with highly alkaline solutions

    NASA Astrophysics Data System (ADS)

    Karnland, Ola; Olsson, Siv; Nilsson, Ulf; Sellin, Patrik

    The estimated quantity of cement for construction and sealing purposes is around 9E5 kg in the planned Swedish KBS3 repository for nuclear waste. The highly alkaline cement pore fluid (pH > 12) may affect other components in the repository, and especially the bentonite buffer is of concern. In this study, we simulated possible interactions between cement and bentonite by contacting highly compacted bentonite with high molar hydroxide solutions in a series of laboratory experiments. Wyoming bentonite (MX-80) and purified homo-ionic Na- and Ca-montmorillonite were used for tests with 0.1, 0.3 and 1.0 M NaOH, and saturated Ca(OH) 2 solutions. Pressure cells with permeable filters were loaded with compacted discs of bentonite at the proposed buffer density (2000 kg/m 3 at full water saturation). A hydroxide solution was circulated on one side of the cell and an isotonic chloride solution on the other during a minimum of 45 days. Swelling pressure and solution pH were monitored during the tests and the change in the solution composition and bentonite mineralogy were determined after completed tests. No effect on swelling pressure was observed in tests with 0.1 M NaOH (pH 12.9) or saturated Ca(OH) 2 solutions (pH 12.4) and the mineralogical/chemical changes of the clay were minimal. The bentonite swelling pressure was significantly reduced in the tests with 0.3 (pH 13.3) and 1.0 M (pH 13.8) NaOH solutions. The reduction seems to be due to an instant osmotic effect, and to a continuous dissolution of silica minerals, resulting in mass loss and, consequently, a decrease in density. At these high pH, the release of silica was dominating and the CEC of the clay increased by 20-25%. The structural formula of the smectite and X-ray diffraction tests for non-expandability (Greene-Kelly test) provided strong evidence that the dissolution of montmorillonite proceeds incongruently through an initial step of beidellitization. The calculated rate of silica release from

  3. Focal brain trauma in the cryogenic lesion model in mice.

    PubMed

    Raslan, Furat; Albert-Weißenberger, Christiane; Ernestus, Ralf-Ingo; Kleinschnitz, Christoph; Sirén, Anna-Leena

    2012-01-01

    The method to induce unilateral cryogenic lesions was first described in 1958 by Klatzo. We describe here an adaptation of this model that allows reliable measurement of lesion volume and vasogenic edema by 2, 3, 5-triphenyltetrazolium chloride-staining and Evans blue extravasation in mice. A copper or aluminium cylinder with a tip diameter of 2.5 mm is cooled with liquid nitrogen and placed on the exposed skull bone over the parietal cortex (coordinates from bregma: 1.5 mm posterior, 1.5 mm lateral). The tip diameter and the contact time between the tip and the parietal skull determine the extent of cryolesion. Due to an early damage of the blood brain barrier, the cryogenic cortical injury is characterized by vasogenic edema, marked brain swelling, and inflammation. The lesion grows during the first 24 hours, a process involving complex interactions between endothelial cells, immune cells, cerebral blood flow, and the intracranial pressure. These contribute substantially to the damage from the initial injury. The major advantage of the cryogenic lesion model is the circumscribed and highly reproducible lesion size and location. PMID:22480252

  4. Overcoming confinement limited swelling in hydrogel thin films using supramolecular interactions.

    PubMed

    Wiener, Clinton G; Weiss, R A; Vogt, Bryan D

    2014-09-21

    The thin film behavior of poly(N-isopropylacrylamide-stat-2-(N-ethylperfluorooctane sulfonamido)ethyl acrylate) (NIPAAm-stat-FOSA) based hydrogels containing 5 mol% FOSA was elucidated using quartz crystal microbalance with dissipation (QCM-D) in combination with spectroscopic ellipsometry (SE) through examination of the lower critical solution temperature (LCST) and temperature dependent swelling for (dry) thicknesses ranging from 10 nm to 121 nm. For all thin films measured, the LCST was shown to slightly increase (>3 °C) in comparison to that of the bulk sample. However for these films, the increase in LCST was statistically identical, irrespective of thickness. Surprisingly, the volumetric swelling of the hydrogel in thin films, even at temperatures less than the LCST, was similar (within 20%) to the volumetric swelling of the bulk hydrogel, despite the expected significant decrease associated with the hydrogel being constrained by the substrate as predicted by one dimensional Flory-Rehner theory. We attribute this enhancement in swelling compared to theoretical expectations to the ability of the hydrophobic crosslinks to re-arrange under stress, which provides a mechanism to alleviate the decreased dimensionality imposed by the substrate; this mechanism is consistent with a large hysteresis in the swelling when cycling between 35 °C and 5 °C. Unlike the LCST, the swelling ratio increases with decreasing film thickness. At low temperatures (below the LCST), the volume swelling ratio increased from 3.9 to 4.9, while at temperatures above the LCST the swelling ratio increased from 1.5 to 2.5 when the film thickness decreased from 121 nm to 10 nm. The combination of facile processing through solution casting without the need for additional crosslinking chemistry and limited thickness dependent variation of swelling and LCST behavior in these physically crosslinked hydrogels makes these materials attractive for applications requiring thermoresponsive soft

  5. Modeling swelling and absorption dynamics for holographic sensing in analytes sensitive photopolymer

    NASA Astrophysics Data System (ADS)

    Liu, Hongpeng; Yu, Dan; Mao, Dongyao; Geng, Yaohui; Wang, Weibo

    2016-06-01

    A theoretical model is developed to describe holographic sensing and swelling of grating fringe in photopolymer. In experiments, diffraction spectrum responses of grating are characterized to exhibit holographic sensing processes. Analytic expressions between swelling of grating fringe and environmental factors, such as relative humidity and organic vapor concentrations, are extracted based on experimental results. The primary factors are introduced into the model to simulate the sensing process, including swelling ratio, nanozeolites dispersion, and organic vapor absorption. Finally, numerical results are presented for improving the sensitivity of holographic sensor. This work can accelerate the development of holographic sensor and provide a theoretical base for exploring sensing mechanism of polymer.

  6. Structure within thin epoxy films revealed by solvent swelling: A neutron reflectivity study

    SciTech Connect

    KENT,MICHAEL S.; YIM,HYUN; MCNAMARA,WILLIAM FRERE; IVKOV,R.; SATIJA,S.; MAJEWSKI,J.

    2000-03-02

    The focus of this work is the structure within highly crosslinked, two component epoxy films. The authors examine variations in crosslink density within thin epoxy films on silicon substrates by solvent swelling. The method is based on the fact that the equilibrium volume fraction of a swelling solvent is strongly dependent upon the local crosslink density. The authors examine the volume fraction profile of the good solvent nitrobenzene through the epoxy films by neutron reflection. Isotopic substitution is used to provide contrast between the epoxy matrix and the swelling solvent.

  7. Over-estimation of glucose-6-phosphatase activity in brain in vivo. Apparent difference in rates of (2-TH)glucose and (U- UC)glucose utilization is due to contamination of precursor pool with UC-labeled products and incomplete recovery of UC-labeled metabolites

    SciTech Connect

    Dienel, G.A.; Nelson, T.; Cruz, N.F.; Jay, T.; Crane, A.M.; Sokoloff, L.

    1988-12-25

    Significant dephosphorylation of glucose 6-phosphate due to glucose-6-phosphatase activity in rat brain in vivo was recently reported. The evidence was an apparent more rapid TH than UC loss from the glucose pool and faster (2-TH)glucose than (U- UC)glucose utilization following pulse labeling of the brain with (2-TH,U- UC)glucose. Radiochemical purity of the glucose and quantitative recovery of the labeled products of glucose metabolism isolated from the brain were obviously essential requirements of their study, but no evidence for purity and recovery was provided. When we repeated these experiments with the described isolation procedures, we replicated the results, but found that: 1) the precursor glucose pool contained detritiated, UC-labeled contaminants arising from glucose metabolism, particularly 2-pyrrolidone-5-carboxylic acid derived from ( UC)glutamine; 2) ( UC)glucose metabolite were not quantitatively recovered; 3) the procedure used to isolate the glucose itself produced detritiated, UC-labeled derivatives of (2-TH,U-14C)glucose. These deficiencies in the isolation procedures could fully account for the observations that were interpreted as evidence of significant glucose 6-phosphate dephosphorylation by glucose-6-phosphatase activity. When glucose was isolated by more rigorous procedures and its purity verified in the present studies, no evidence for such activity in rat brain was found.

  8. Analysis of Biophysical Mechanisms of Gilgai Microrelief Formation in Dryland Swelling Soils Using Ultra-High Resolution Aerial Imagery

    NASA Astrophysics Data System (ADS)

    Krell, N.; DeCarlo, K. F.; Caylor, K. K.

    2015-12-01

    Microrelief formations ("gilgai"), which form due to successive wetting-drying cycles typical of swelling soils, provide ecological hotspots for local fauna and flora, including higher and more robust vegetative growth. The distribution of these gilgai suggests a remarkable degree of regularity. However, it is unclear to what extent the mechanisms that drive gilgai formation are physical, such as desiccation-induced fracturing, or biological in nature, namely antecedent vegetative clustering. We investigated gilgai genesis and pattern formation in a 100 x 100 meter study area with swelling soils in a semiarid grassland at the Mpala Research Center in central Kenya. Our ongoing experiment is composed of three 9m2 treatments: we removed gilgai and limited vegetative growth by herbicide application in one plot, allowed for unrestricted seed dispersal in another, and left gilgai unobstructed in a control plot. To estimate the spatial frequencies of the repeating patterns of gilgai, we obtained ultra-high resolution (0.01-0.03m/pixel) images with an unmanned aerial vehicle (UAV) from which digital elevation models were also generated. Geostatistical analyses using wavelet and fourier methods in 1- and 2-dimensions were employed to characterize gilgai size and distribution. Preliminary results support regular spatial patterning across the gilgaied landscape and heterogeneities may be related to local soil properties and biophysical influences. Local data on gilgai and fracture characteristics suggest that gilgai form at characteristic heights and spacing based on fracture morphology: deep, wide cracks result in large, highly vegetated mounds whereas shallow cracks, induced by animal trails, are less correlated with gilgai size and shape. Our experiments will help elucidate the links between shrink-swell processes and gilgai-vegetation patterning in high activity clay soils and advance our understanding of the mechanisms of gilgai formation in drylands.

  9. Phaeohyphomycosis Due to Exophiala jeanselmei: An Emerging Pathogen in India--Case Report and Review.

    PubMed

    Bhardwaj, Swati; Capoor, Malini R; Kolte, Sachin; Purohit, Geeta; Dawson, Leelavathi; Gupta, Kusum; Ramesh, V; Mandal, Ashish Kumar

    2016-04-01

    We present a rare case of a 30-year-old woman who presented with a swelling on the lateral aspect of her left forearm, present since 6 months, adjacent to a 16-year-old burn scar. X-ray of elbow joint and forearm revealed the subcutaneous nature of the swelling. Giemsa and periodic acid-Schiff-stained smears and potassium hydroxide mount of fine-needle aspirate of the swelling revealed dematiaceous, branching, and septate fungal hyphae. Fungal culture of the aspirated pus showed growth of Exophiala jeanselmei. Histopathological examination revealed brown-coloured hyphae with foreign body giant cell reaction and palisading granulomas in the surrounding tissue. The patient was successfully treated with surgical excision of the swelling. All the cases of phaeohyphomycosis due to Exophiala spp. in India are also reviewed. PMID:26476655

  10. Nature and distribution of brain lesions in rats intoxicated with 3-nitropropionic acid: a type of hypoxic (energy deficient) brain damage.

    PubMed

    Hamilton, B F; Gould, D H

    1987-01-01

    The clinical signs and morphological brain lesions associated with histotoxic hypoxia induced by subcutaneous injection of 3-nitropropionic acid (NPA) in rats are described, and compared to hypoxic brain damage from other causes including ischemia and hypoglycemia. The brains were perfusion-fixed with paraformaldehyde/glutaraldehyde fixative, and examined by light and electron microscopy. Intoxicated rats developed severe neurological disease characterized by somnolence, uncoordinated gait with stereotypical paddling movements, and ventral or lateral recumbency. Recumbent rats had a selective, bilaterally symmetrical pattern of severe morphological injury in the caudate-putamen, hippocampus, and thalamus. Recumbency was a consistent indicator of the development of morphological brain lesions. In contrast to reports describing rat models of ischemia and hypoglycemia, morphological injury was not seen in the cerebral and cerebellar cortices of NPA-intoxicated rats. Ultrastructurally, neuronal alterations ranged from chromatin clumping with increased cytoplasmic lucency to severe cellular shrinkage or swelling with marked mitochondrial swelling (high amplitude swelling). White matter alterations included axonal swelling and adaxonal splitting of myelin lamellae. Vascular changes included perivascular deposits of proteinaceous material presumably from leakage of serum proteins, variable electron lucency of endothelial cell cytoplasm, an apparent increase in pinocytotic vesicles, rare platelet thrombosis of capillaries, and rare intravascular blebs of luminal plasma membrane. As a model of brain damage following energy deficiency, NPA intoxication has the advantages of producing morphological brain injury in a highly predictable anatomical pattern, and at a time paralleling the onset of clinical recumbency.

  11. Stress-strain relations for swelling anhydritic clay rocks – A review

    NASA Astrophysics Data System (ADS)

    Breuer, Simon; Blum, Philipp; Butscher, Christoph

    2015-04-01

    The swelling of clay-sulfate rocks is a major threat in tunnel engineering, causing serious damage to tunnels and producing high additional costs during tunnel construction and operation. The swelling leads to geomechanical processes that may result in heave of the tunnel invert, destruction of the lining or uplift of the entire tunnel section. Heave-pressure-time relations are needed when predictions should be made about the mechanical behavior of swelling rock. For pure clay rocks, there is a linear relation between the swelling heave (strain) and the logarithm of pressure (Grob 1972). A generally accepted relation for clay-sulfate rocks, however, is still lacking to date. Therefore, finding appropriate and sustainable counter measures for an actual tunneling project affected by swelling remains extremely difficult. Grob (1972) proposed the linear relation between heave and the logarithm of pressure ("semi-logarithmic swelling law") not only for clay rocks, but also for clay-sulfate rocks. Pimentel (2007), however, presented laboratory experiments indicating that the semi-logarithmic swelling law may be inadequate for describing the swelling of clay-sulfate rocks. The laboratory tests revealed three different stages in the swelling process, including minimal deformation and prevented gypsum crystallization at high pressures (> 6 MPa); large deformation and gypsum crystallization at medium pressures; and only small deformation, possibly along with gypsum dissolution, at low pressures (< 4 MPa). He pointed at a "tri-linear" relation to describe the different stages. Kirschke (1995) generally doubts the existence of a fixed relation between swelling strain and (final) pressure. According to him, swelling pressures and their temporal development are controlled by water inflow into the rock, which cannot be reflected by general strain-stress relations. The present study critically reviews stress-strain relations for swelling anhydritic clay rocks proposed by various

  12. Mathematical modelling of blood-brain barrier failure and edema

    NASA Astrophysics Data System (ADS)

    Waters, Sarah; Lang, Georgina; Vella, Dominic; Goriely, Alain

    2015-11-01

    Injuries such as traumatic brain injury and stroke can result in increased blood-brain barrier permeability. This increase may lead to water accumulation in the brain tissue resulting in vasogenic edema. Although the initial injury may be localised, the resulting edema causes mechanical damage and compression of the vasculature beyond the original injury site. We employ a biphasic mixture model to investigate the consequences of blood-brain barrier permeability changes within a region of brain tissue and the onset of vasogenic edema. We find that such localised changes can indeed result in brain tissue swelling and that the type of damage that results (stress damage or strain damage) depends on the ability of the brain to clear edema fluid.

  13. Improved interpretation of in-diffusion measurements with confined swelling clays.

    PubMed

    Yaroshchuk, Andriy E; Van Loon, Luc R

    2008-04-01

    Diffusion is considered the principal transport mechanism of radio-nuclides and other low-molecular-weight pollutants in compacted clays used as barriers at various disposal and storage sites, for example, at projected deep repositories for radioactive waste. Porous filters are routinely used to confine swelling clays in diffusion studies of radio-tracers. The presence of the filter gives rise to considerable mass-transfer limitations at the clay boundary that result in erroneous diffusion parameters. We have solved the problem of in-diffusion with due account for this phenomenon by means of Fourier transforms. By using literature data on the in-diffusion of traces of radioactive cesium in an argillaceous rock (Opalinus clay) and a compacted bentonite (FEBEX bentonite), we have demonstrated that taking into account the mass-transfer limitations considerably improves the quality of the theoretical fit of the time evolution of radio-tracer concentration in the reservoir. Besides that, we have shown that ignoring the mass-transfer limitations leads to a noticeable underestimation of both the effective diffusion coefficient and the specific sorption capacity of the clay. PMID:18291558

  14. Comprehensive Prediction of Large-height Swell-like Waves in East Coast of Korea

    NASA Astrophysics Data System (ADS)

    Kwon, S. J.; Lee, C.; Ahn, S. J.; Kim, H. K.

    2014-12-01

    There have been growing interests in the large-height swell-like wave (LSW) in the east coast of Korea because such big waves have caused human victims as well as damages to facilities such as breakwaters in the coast. The LSW was found to be generated due to an atmospherically great valley in the north area of the East Sea and then propagate long distance to the east coast of Korea in prominently southwest direction (Oh et al., 2010).In this study, we will perform two methods, real-time data based and numerical-model based predictions in order to predict the LSW in the east coast of Korea. First, the real-time data based prediction method uses information which is collected by the directional wave gauge installed near Sokcho. Using the wave model SWAN (Booij et al., 1999) and the wave ray method (Munk and Arthur, 1952), we will estimate wave data in open sea from the real-time data and predict the travel time of LSW from the measurement site (near Sokcho) to several target points in the east coast of Korea. Second, the numerical-model based method uses three different numerical models; WW3 in deep water, SWAN in shallow water, and CADMAS-SURF for wave run-up (CDIT). The surface winds from the 72 hours prediction system of NCEP (National Centers for Environmental Prediction) GFS (Global Forecast System) will be inputted in finer grids after interpolating these in certain domains of WW3 and SWAN models. The significant wave heights and peak wave directions predicted by the two methods will be compared to the measured data of LSW at several target points near the coasts. Further, the prediction method will be improved using more measurement sites which will be installed in the future. ReferencesBooij, N., Ris, R.C., and Holthuijsen, L.H. (1999). A third-generation wave model for coastal regions 1. Model description and validation. J. of Geophysical Research, 103(C4), 7649-7666.Munk, W.H. and Arthur, R.S. (1952). Gravity Waves. 13. Wave Intensity along a Refracted Ray

  15. Reversible swelling of the cell wall of poplar biomass by ionic liquid at room temperature

    PubMed Central

    Lucas, Marcel; Wagner, Greg L.; Nishiyama, Yoshiharu; Hanson, Leif; Samayam, Indira P.; Schall, Constance A.; Langan, Paul; Rector, Kirk D.

    2012-01-01

    Time-resolved autofluorescence, Raman microspectroscopy, and scanning microprobe X-ray diffraction were combined in order to characterize lignocellulosic biomass from poplar trees and how it changes during treatment with the ionic liquid 1-n-ethyl-3-methylimidazolium acetate (EMIMAC) at room temperature. The EMIMAC penetrates the cell wall from the lumen, swelling the cell wall by about a factor of two towards the empty lumen. However, the middle lamella remains unchanged, preventing the cell wall from swelling outwards. During this swelling, most of the cellulose microfibrils are solubi-lized but chain migration is restricted and a small percentage of microfibrils persist. When the EMIMAC is expelled, the cellulose recrystallizes as microfibrils of cellulose I. There is little change in the relative chemical composition of the cell wall after treatment. The action of EMIMAC on the poplar cell wall at room temperature would therefore appear to be a reversible swelling and a reversible decrystallization of the cell wall. PMID:21247757

  16. Patterned dual pH-responsive core-shell hydrogels with controllable swelling kinetics and volumes.

    PubMed

    Plunkett, Kyle N; Moore, Jeffrey S

    2004-08-01

    Dual pH-responsive core-shell hydrogels containing both a vinyl pyridine component and a 2-dimethylaminoethyl methacrylate component were prepared using an in situ photopolymerization process. Complementary photomasks were utilized to prepare hydrogels with core/shell volume ratios of 2:1, 1:1, and 1:2. Depending on the location of each polymer component, dramatically different swelling profiles were achieved. Selective swelling of the shell followed by the core components allowed the hydrogel to expand with the usual kinetics; however, by switching the location of each polymer component and swelling the core first, swelling rates decreased by over 1 order of magnitude and were dependent on the shell component's volume. The ability to pattern core/shell volumes also provided the ability to fabricate hydrogels that possess a constant maximum diameter but different cutoff points between its first and its second transition volumes. These materials may be of interest for controlled release applications. PMID:15274549

  17. Dissolution And Swelling Studies Of Poly(Methyl Methacrylate) Resist Films

    NASA Astrophysics Data System (ADS)

    Papanu, J. S.; Manjkow, J.; Hess, D. W.; Soong, D. S.; Bell, A. T.

    1987-08-01

    The swelling and dissolution of thin film poly(methyl methacrylate), PMMA, in methyl isobutyl ketone (MIBK), and in solvent/nonsolvent mixtures of MIBK/methanol and methyl ethyl ketone/isopropanol have been investigated. Films were monitored using in situ ellipsometry. Parametric studies of the effects of molecular weight, molecular weight distribution, softbaking quench rate, solvent size, and temperature were performed with MIBK. These parameters were shown to have a significant effect on dissolution. The effects of solvent composition and temperature on swelling and dissolution were investigated with the binary solvents. Ternary diagrams based on Flory-Huggins interaction parameters were used to interpret the thermodynamics of swelling and dissolution. A narrow transition region (NTR) where the developer changed from a swelling to dissolving agent with a small change in composition or temperature was observed.

  18. Coupling behavior of the pH/temperature sensitive hydrogels for the inhomogeneous and homogeneous swelling

    NASA Astrophysics Data System (ADS)

    Mazaheri, H.; Baghani, M.; Naghdabadi, R.; Sohrabpour, S.

    2016-08-01

    In this work, a model is developed to continuously predict homogeneous and inhomogeneous swelling behavior of pH/temperature sensitive PNIPAM hydrogels. Employing the model, homogeneous swelling of the pH/temperature sensitive hydrogel is investigated for free and biaxial constrained swelling cases. Comparing the model results with the experimental data available in the literature, the validity of the model is confirmed. The model is then employed to investigate inhomogeneous swelling of a spherical shell on a hard core both analytically and numerically for pH or temperature variations. In this regard, numerical tools are developed via preparing a user defined subroutine in ABAQUS software. Then, the complicated problem of contact between the hydrogel shell and a micro-channel with rigid walls is also investigated. Considering the results, we can say that the model is applicable for solving engineering boundary value problem of pH/temperature sensitive hydrogels.

  19. Influence of nickel and beryllium content on swelling behavior of copper irradiated with fast neutrons

    SciTech Connect

    Singh, B.N.; Garner, F.A.; Edwards, D.J.; Evans, J.H.

    1996-10-01

    In the 1970`s, the effects of nickel content on the evolution of dislocation microstructures and the formation and growth of voids in Cu-Ni alloys were studied using 1 MeV electrons in a high voltage electron microscope. The swelling rate was found to decrease rapidly with increasing nickel content. The decrease in the swelling rate was associated with a decreasing void growth rate with increasing nickel content at irradiation temperatures up to 450{degrees}C. At 500{degrees}C, both void size and swelling rate were found to peak at 1 and 2% Ni, respectively, and then to decrease rapidly with increasing nickel content. However, recent work has demonstrated that the swelling behavior of Cu-5%Ni irradiated with fission neutrons is very similar for that of pure copper. The present experiments were designed to investigate this apparent discrepancy.

  20. Bilayer mass transport model for determining swelling and diffusion in coated, ultrathin membranes.

    PubMed

    Nadermann, Nichole K; Chan, Edwin P; Stafford, Christopher M

    2015-02-18

    Water transport and swelling properties of an ultrathin, selective polyamide layer with a hydrophilic polymer coating, i.e., a polymer bilayer, are studied using quartz crystal microbalance with dissipation (QCM-D). Specifically, QCM-D is used to measure the dynamic and equilibrium change in mass in a series of differential sorption experiments to determine the dependence of the apparent diffusion coefficient and equilibrium swelling of the bilayer as a function of the water vapor activity. To determine transport properties specific to the polyamide layer, sorption kinetics of the bilayer was modeled with a bilayer mass transport model. The swelling and water diffusion coefficients are interpreted according to the Painter-Shenoy polymer network swelling model and the solution-diffusion model, respectively.

  1. X-ray diffraction study of the kinetics of myelin lattice swelling. Effect of divalent cations.

    PubMed Central

    Padrón, R; Mateu, L; Kirschner, D A

    1979-01-01

    The time-course of myelin lattice swelling and its reversal in dissected peripheral nerves was determined by small-angle x-ray diffraction using a position-sensitive proportional detector. The process of swelling can take place either in several hours or in less than 1 h depending on pretreatment of the nerves. The reversal of swelling was always completed within 1 h. The rapid structural transitions involved the disordering of membrane pairs as indicated by the transient appearance of a continuous intensity distribution similar to the membrane pair transform for myelin. The slow transitions involved the gradual replacement of the discrete reflections from the native structure by the reflections from the swollen lattice. Myelin membrane arrays reformed in normal Ringer's solution were much more stable to subsequent swelling than arrays reformed in Ca+2 and Mg+2-free Ringer's. These results suggest that these ions participate in stabilizing the interactions between the external surfaces of adjacent membrane pairs. PMID:122265

  2. Solvent Swelling as a Means to Modify the Properties of Polymer Thin Films

    NASA Astrophysics Data System (ADS)

    Clough, Andrew; Tsui, Ophelia; Chowdhury, Mithun; Jahanshahi, Kaiwan; Reiter, Guenter

    2012-02-01

    It has been observed that sample preparation can influence certain properties of polymer films. In particular, spin-coating from solutions of different solvent qualities result in films with different chain conformations. We surmise that upon formation by spin-coating, the chain conformation of a film is still adjustable by means of solvent swelling, resulting in modifications to the amount of entanglement and free volume. Initial measurements of thermal expansion upon heating after swelling suggest that there is a difference between polystyrene films swelled with a good solvent and a θ solvent. We have begun a more detailed investigation by studying the effect of swelling on the dewetting behaviors. Preliminary data indicates that the quality of the solvent affects both the dewetting hole size and aging rate of the film.

  3. Effect of irradiation temperature on void swelling of China Low Activation Martensitic steel (CLAM)

    SciTech Connect

    Zhao Fei; Qiao Jiansheng; Huang Yina; Wan Farong Ohnuki, Soumei

    2008-03-15

    CLAM is one composition of a Reduced Activation Ferritic/Martensitic steel (RAFM), which is being studied in a number of institutes and universities in China. The effect of electron-beam irradiation temperature on irradiation swelling of CLAM was investigated by using a 1250 kV High Voltage Electron Microscope (HVEM). In-situ microstructural observations indicated that voids formed at each experimental temperature - 723 K, 773 K and 823 K. The size and number density of voids increased with increasing irradiation dose at each temperature. The results show that CLAM has good swelling resistance. The maximum void swelling was produced at 723 K; the swelling was about 0.3% when the irradiation damage was 13.8 dpa.

  4. Swelling and Thermo-Mechanical Behavior of Smectitic Clay in the San Andreas Fault at Parkfield/California

    NASA Astrophysics Data System (ADS)

    Hofmann, H.; Schleicher, A. M.; van der Pluijm, B. A.

    2011-12-01

    There is growing agreement that smectitic clays play a key role in the behavior of fault rocks from the SAFOD (San Andreas Fault Observatory at Depth) borehole at Parkfield, California. In this study, we focus on the swelling behavior of Mg-rich smectite from the central deformation zone at 3298.4 m, in order to evaluate the occurrence and intake of water in smectite, and its relation to fault zone weakening processes. Understanding swelling behavior is also critical for meaningful laboratory experiments on clay-rich fault rocks. A textured sample of the clay size fraction (< 2 micron) of the sample was measured by X-ray diffraction (XRD) under controlled temperature and humidity conditions, at temperatures of 25°C, 50°C, 75°C, and 95°C, and humidity ranging from 10% Relative Humidity (RH) to 98 %RH. The air-dried sample shows a smectite phase with a characteristic interlayer distance (d-value) of 1.1 nm that increases to 1.4 nm after ethylene glycolization, indicating 1 to 1.5 H2O in the interlayer. With increasing temperatures to 95°C and humidity up to 95 %RH, all samples show similar x-ray patterns, with a stable smectite phase during the entire hydration/heating process. With increasing humidity under isothermal conditions, the hydration of interlayer cations and the particle orientation increases, indicated by increasing d-values and increasing intensities. On the other hand, the intensities under stable humidity and increasing temperature decrease due to lattice distortion and scattering effects. At 25°C and 10 %RH, the sample is a mix of dehydrated smectite (1.1 nm) and 1H2O (1.2 nm) in the interlayer space, which increases to 1.3 nm at 20 % and 30 %RH. Between 30 and 95 %RH, there is a slow transition from 1.3 nm to 1.4 nm (1 H2O to 1.5 H2O). The patterns at 50°C, 75°C and 95°C show similar behavior with slightly lower interlayer spacing. At 95°C, an additional peak appeared with increasing humidity, indicating the formation of an additional

  5. [Traumatic brain injury].

    PubMed

    Hackenberg, K; Unterberg, A

    2016-02-01

    Since traumatic brain injury is the most common cause of long-term disability and death among young adults, it represents an enormous socio-economic and healthcare burden. As a consequence of the primary lesion, a perifocal brain edema develops causing an elevation of the intracranial pressure due to the limited intracranial space. This entails a reduction of the cerebral perfusion pressure and the cerebral blood flow. A cerebral perfusion deficit below the threshold for ischemia leads to further ischemic lesions and to a progression of the contusion. As the irreversible primary lesion can only be inhibited by primary prevention, the therapy of traumatic brain injury focuses on the secondary injuries. The treatment consists of surgical therapy evacuating the space-occupying intracranial lesion and conservative intensive medical care. Due to the complex pathophysiology the therapy of traumatic brain injury should be rapidly performed in a neurosurgical unit. PMID:26810405

  6. Brain iron homeostasis.

    PubMed

    Moos, Torben

    2002-11-01

    [125I]transferrin in the brain. Some of the 59Fe was detected in CSF in a fraction less than 30 kDa (III). It was estimated that the iron-binding capacity of transferrin in CSF was exceeded, suggesting that iron is transported into the brain in a quantity that exceeds that of transferrin. Accordingly, it was concluded that the paramount iron transport across the BBB is the result of receptor-mediated endocytosis of iron-containing transferrin by capillary endothelial cells, followed by recycling of transferrin to the blood and transport of non-transferrin-bound iron into the brain. It was found that retrograde axonal transport in a cranial motor nerve is age-dependent, varying from almost negligible in the neonatal brain to high in the adult brain. The principle sources of extracellular transferrin in the brain are hepatocytes, oligodendrocytes, and the choroid plexus. As the passage of liver-derived transferrin into the brain is restricted due to the BBB, other candidates for binding iron in the interstitium should be considered. In vitro studies have revealed secretion of transferrin from the choroid plexus and oligodendrocytes. The second part of the thesis encompasses the circulation of iron in the extracellular fluids of the brain, i.e. the brain interstitial fluid and the CSF. As the latter receives drainage from the interstitial fluid, the CSF of the ventricles can be considered a mixture of these fluids, which may allow for analysis of CSF in matters that relate to the brain interstitial fluid. As the choroid plexus is known to synthesize transferrin, a key question is whether transferrin of the CSF might play a role for iron homeostasis by diffusing from the ventricles and subarachnoid space to the brain interstitium. Intracerebroventricular injection of [59Fe125I]transferrin led to a higher accumulation of 59Fe than of [125I]transferrin in the brain. Except for uptake and axonal transport by certain neurons with access to the ventricular CSF, both iron and

  7. Towards a system-paced near-infrared spectroscopy brain-computer interface: differentiating prefrontal activity due to mental arithmetic and mental singing from the no-control state

    NASA Astrophysics Data System (ADS)

    Power, Sarah D.; Kushki, Azadeh; Chau, Tom

    2011-10-01

    Near-infrared spectroscopy (NIRS) has recently been investigated as a non-invasive brain-computer interface (BCI) for individuals with severe motor impairments. For the most part, previous research has investigated the development of NIRS-BCIs operating under synchronous control paradigms, which require the user to exert conscious control over their mental activity whenever the system is vigilant. Though functional, this is mentally demanding and an unnatural way to communicate. An attractive alternative to the synchronous control paradigm is system-paced control, in which users are required to consciously modify their brain activity only when they wish to affect the BCI output, and can remain in a more natural, 'no-control' state at all other times. In this study, we investigated the feasibility of a system-paced NIRS-BCI with one intentional control (IC) state corresponding to the performance of either mental arithmetic or mental singing. In particular, this involved determining if these tasks could be distinguished, individually, from the unconstrained 'no-control' state. Deploying a dual-wavelength frequency domain near-infrared spectrometer, we interrogated nine sites around the frontopolar locations (International 10-20 System) while eight able-bodied adults performed mental arithmetic and mental singing to answer multiple-choice questions within a system-paced paradigm. With a linear classifier trained on a six-dimensional feature set, an overall classification accuracy of 71.2% across participants was achieved for the mental arithmetic versus no-control classification problem. While the mental singing versus no-control classification was less successful across participants (62.7% on average), four participants did attain accuracies well in excess of chance, three of which were above 70%. Analyses were performed offline. Collectively, these results are encouraging, and demonstrate the potential of a system-paced NIRS-BCI with one IC state corresponding to

  8. Magnetic resonance spectroscopy of the ischemic brain under lithium treatment. Link to mitochondrial disorders under stroke.

    PubMed

    Silachev, Denis N; Gulyaev, Mikhail V; Zorova, Ljubava D; Khailova, Ljudmila S; Gubsky, Leonid V; Pirogov, Yury A; Plotnikov, Egor Y; Sukhikh, Gennady T; Zorov, Dmitry B

    2015-07-25

    Recent evidence suggests that mitochondria are one of the main factors in the pathogenesis in different organs including brain. The pathogenesis after brain damage is caused not only by the change in bioenergetics, but also involves impairment of alternative functions of mitochondria, particularly those related to the control of cell death. In this study we evaluated partial metabolic pathways under the simulation of a stroke by using the occlusion of the middle cerebral artery in rats. The analysis shows that the induced switch to a non-oxidative energy metabolism (glycolysis) due to the block of tissue oxygen supply does not ensure the adequate supply of the tissue with ATP. Moreover, the well-known acidification of the ischemic tissue is not associated with the so-called traditionally and incorrectly considered "lactic acidosis" (the generation of lactate from glucose by itself does not lead to excessive generation of protons), but occurs because of the consumption of tissue ATP under its reduced resynthesis. Incubation of mitochondria isolated from normal rat brain at neutral and slightly acidic pH, mimicking the intracellular pH of normal and ischemic tissues correspondingly, revealed serious changes in mitochondrial bioenergetics, partially reflected in the magnitude of respiratory control and the basal and maximally stimulated respiration rates. Measurement of available metabolites by (1)H MR spectra of normal and ischemia-damaged brains showed a significant increase in lactate and myo-inositol and a moderate decrease in N-acetylaspartate 24h after reperfusion. Remarkably, the administration of lithium chloride in the reperfusion phase normalized the levels of metabolites. Moreover, the introduction of lithium salts (chloride or succinate) in the bloodstream, restored after ischemia, reduced both the size of the ischemia-induced brain damage and the degree of brain swelling. Besides, post-ischemic introduction of lithium salts largely restored the

  9. Pinch and swell structures: evidence for brittle-viscous behaviour in the middle crust

    NASA Astrophysics Data System (ADS)

    Gardner, R.; Piazolo, S.; Daczko, N.

    2015-04-01

    The flow properties of middle to lower crustal rocks are commonly represented by viscous flow. However, examples of pinch and swell structures found in a mid-crustal high strain zone at St. Anne Point (Fiordland, New Zealand) suggest pinch and swell structures are initiated by brittle failure of the more competent layer in conjunction with material softening. On this basis we develop a flexible numerical model using brittle-viscous flow where Mohr-Coulomb failure is utilised to initiate pinch and swell structure development. Results show that pinch and swell structures develop in a competent layer in both Newtonian and non-Newtonian flow provided the competent layer has enough viscosity contrast and initially fails brittlely. The degree of material softening after initial failure is shown to impact pinch and swell characteristics with high rates of material softening causing the formation of thick necks between swells by limiting the successful localisation of strain. The flow regime and yielding characteristics of the matrix do not impact pinch and swell structure formation itself, so long as the matrix is less competent. To aid analysis of the structures and help derive the flow properties of rocks in the field, we define three stages of pinch and swell development and offer suggestions for measurements to be made in the field. Our study suggests that Mohr-Coulomb behaviour combined with viscous flow is an appropriate way to represent the heterogeneous rocks of the middle to lower crust. This type of mid-crustal rheological behaviour has significant influence on the localization of strain at all scales. For example, inclusion of Mohr-Coulomb brittle failure with viscous flow in just some mid-crustal layers within a crustal scale model will result in strain localisation throughout the whole crustal section allowing the development of through-going high strain structures from the upper crust into the middle and lower crust. This localization then has a significant

  10. Observations of void swelling in selected austenitic alloys during ion irradiation under a rising temperature ramp

    NASA Astrophysics Data System (ADS)

    Mazey, D. J.; Williams, T. M.; Bolster, D. E. J.

    1988-07-01

    Results are given of a TEM study of the void swelling behaviour of CW AISI 321 (En58B), CW FV548 stainless steel and STA Nimonic PE16 alloy during 46 MeV nickel ion irradiation under a near-linear rising temperature ramp. The dose range for the ramp was 0-75 dpa and four temperature ranges were investigated using 50 ° C intervals from 500-550 ° C, 525-575 ° C, 575-625 ° C and 625-675 ° C. Swelling in CW 321 was found to be no greater than that observed after isothermal irradiation to 75 dpa at temperatures corresponding to the end-of-ramp temperatures. This was not the case for CW FV548 where the swelling for the temperature ranges of 525-575 ° C and 575-625 ° C was slightly greater than that observed under isothermal irradiation to 75 dpa. Swelling in STA PE16 in the lower temperature ranges of 500-550 ° C and 525-575°C was much higher than corresponding isothermal values but in the 600-700 ° C temperature range the swelling was close to isothermal values. The results on PE16 indicate that a steady increase in irradiation temperature from just below or just above the low temperature cut-off into the void swelling region produces a significant increase in swelling with respect to that expected under isothermal conditions. Possible interpretations of the observed swelling behaviour in these alloys are discussed.

  11. Calculation of radiation induced swelling of uranium mononitride using the digital computer program CYGRO 2

    NASA Technical Reports Server (NTRS)

    Davison, H. W.; Fiero, I. B.

    1971-01-01

    Fuel volume swelling and clad diametral creep strains were calculated for five fuel pins, clad with either T-111 (Ta-8W-2.4Hf) or PWC-11 (Nb-1Zr-0.1C). The fuel pins were irradiated to burnups between 2.7 and 4.6%. Clad temperatures were between 1750 and 2400 F (1228 and 1589 K). The maximum percentage difference between calculated and experimentally measured values of volumetric fuel swelling is 60%.

  12. The domesticated brain: genetics of brain mass and brain structure in an avian species

    PubMed Central

    Henriksen, R.; Johnsson, M.; Andersson, L.; Jensen, P.; Wright, D.

    2016-01-01

    As brain size usually increases with body size it has been assumed that the two are tightly constrained and evolutionary studies have therefore often been based on relative brain size (i.e. brain size proportional to body size) rather than absolute brain size. The process of domestication offers an excellent opportunity to disentangle the linkage between body and brain mass due to the extreme selection for increased body mass that has occurred. By breeding an intercross between domestic chicken and their wild progenitor, we address this relationship by simultaneously mapping the genes that control inter-population variation in brain mass and body mass. Loci controlling variation in brain mass and body mass have separate genetic architectures and are therefore not directly constrained. Genetic mapping of brain regions indicates that domestication has led to a larger body mass and to a lesser extent a larger absolute brain mass in chickens, mainly due to enlargement of the cerebellum. Domestication has traditionally been linked to brain mass regression, based on measurements of relative brain mass, which confounds the large body mass augmentation due to domestication. Our results refute this concept in the chicken. PMID:27687864

  13. Multi-hollow polymer microspheres with enclosed surfaces and compartmentalized voids prepared by seeded swelling polymerization method.

    PubMed

    Tian, Qiong; Yu, Demei; Zhu, Kaiming; Hu, Guohe; Zhang, Lifeng; Liu, Yuhang

    2016-07-01

    Multi-hollow particles have drawn extensive research interest due to their high specific areas and abundant inner voids, whereas their convenient synthesis still remains challenging. In this paper, we report a simple and convenient method based on seeded swelling polymerization to prepare the multi-hollow microspheres with enclosed surfaces and compartmentalized voids using monodisperse poly (styrene-co-sodium 4-vinylbenzenesulfonate) microspheres as seed particles. A formation mechanism of the multi-hollow structure was proposed involving the processes of water absorption, coalescence and stabilization of water domains, immobilization of multi-hollow structure, and coverage of surface dimples. The influencing parameters on the morphology of the microspheres, including weight ratio of sodium 4-vinylbenzenesulfonate to styrene in the seed particles, dosage of the swelling monomer and the crosslinking agent were systematically investigated. The internal structure of the resultant microspheres could be tuned from solid to multi-hollow by controlling over these parameters. Multi-hollow microspheres with compartmentalized chambers, smooth surfaces and narrow size distributions were obtained as a result.

  14. A two-scale non-local model of swelling porous media incorporating ion size correlation effects

    NASA Astrophysics Data System (ADS)

    Le, T. D.; Moyne, C.; Murad, M. A.; Lima, S. A.

    2013-12-01

    A new two-scale model is proposed for derivation of the macroscopic modified effective stress principle for swelling porous media saturated by an electrolyte solution containing finite size ions. A non-local pore-scale model is developed within the framework of Statistical Mechanics in conjunction with the thermodynamic approach based on Density Functional Theory leading to a nonlinear integral Fredholm equation of second kind for the ion/nanopore correlation function coupled with Poisson problem for the electric double layer potential. When combined with the fluid equilibrium condition such non-local electrochemical problem gives rise to a constitutive law for the fluid stress tensor in terms of the disjoining pressure which is decomposed into several components of different nature. The homogenization procedure based on formal asymptotic expansions is applied to up-scale the model to the macroscale leading to a two-scale constitutive law for the swelling pressure appearing in the modified effective stress principle with improved accuracy incorporating the deviations from the Gouy-Chapman Poisson-Boltzmann-based theory due to the finite size short-range ion-ion correlation effects. The integro-differential problem posed in a periodic cell is discretized by collocation schemes. Numerical results are obtained for a stratified arrangement of parallel macromolecules showing that the effects of ion-ion correlation forces give rise to anomalous attraction patterns between the particles for divalent ions.

  15. Multi-hollow polymer microspheres with enclosed surfaces and compartmentalized voids prepared by seeded swelling polymerization method.

    PubMed

    Tian, Qiong; Yu, Demei; Zhu, Kaiming; Hu, Guohe; Zhang, Lifeng; Liu, Yuhang

    2016-07-01

    Multi-hollow particles have drawn extensive research interest due to their high specific areas and abundant inner voids, whereas their convenient synthesis still remains challenging. In this paper, we report a simple and convenient method based on seeded swelling polymerization to prepare the multi-hollow microspheres with enclosed surfaces and compartmentalized voids using monodisperse poly (styrene-co-sodium 4-vinylbenzenesulfonate) microspheres as seed particles. A formation mechanism of the multi-hollow structure was proposed involving the processes of water absorption, coalescence and stabilization of water domains, immobilization of multi-hollow structure, and coverage of surface dimples. The influencing parameters on the morphology of the microspheres, including weight ratio of sodium 4-vinylbenzenesulfonate to styrene in the seed particles, dosage of the swelling monomer and the crosslinking agent were systematically investigated. The internal structure of the resultant microspheres could be tuned from solid to multi-hollow by controlling over these parameters. Multi-hollow microspheres with compartmentalized chambers, smooth surfaces and narrow size distributions were obtained as a result. PMID:27046772

  16. Effect of cyclosporin A and trifluoperazine on rat liver mitochondria swelling and lipid peroxidation.

    PubMed

    Nepomuceno, M F; Pereira-da-Silva, L

    1993-10-01

    The effect of cyclosporin A (CsA) or trifluoperazine (TFP) on lipid peroxidation and mitochondrial swelling was determined using liver mitochondria incubated with 30 microM Ca2+ and 250 microM t-butylhydroperoxide or 5 mM inorganic phosphate (P(i)). Lipid peroxidation was not modified by either 1 microM CsA or 40 microM TFP. These compounds presented a distinct effect on mitochondrial permeability. Under oxidative conditions, CsA only showed a transient protective effect whereas TFP completely inhibited mitochondrial swelling. Conversely, CsA was very efficient when Ca2+ and P(i) were used, a condition under which TFP was unable to prevent the swelling. These data are consistent with our previous results (M.F. Nepomuceno, D.V. Macedo and L. Pereira-da-Silva (1991). Brazilian Journal of Medical and Biological Research, 24: 833-836) showing that lipid peroxidation is one among other different components of the permeabilization process. The data suggest that lipid peroxidation is independent of swelling, occurring later than swelling, presumably when the mitochondrial reductant systems are depleted. The differential effects of CsA and TFP suggest that these compounds can be used as specific probes in the elucidation of the two distinct mechanisms responsible for mitochondrial swelling.

  17. Swelling and Softening of the Cowpea Chlorotic Mottle Virus in Response to pH Shifts

    PubMed Central

    Wilts, Bodo D.; Schaap, Iwan A.T.; Schmidt, Christoph F.

    2015-01-01

    Cowpea chlorotic mottle virus (CCMV) forms highly elastic icosahedral protein capsids that undergo a characteristic swelling transition when the pH is raised from 5 to 7. Here, we performed nano-indentation experiments using an atomic force microscope to track capsid swelling and measure the shells’ Young’s modulus at the same time. When we chelated Ca2+ ions and raised the pH, we observed a gradual swelling of the RNA-filled capsids accompanied by a softening of the shell. Control experiments with empty wild-type virus and a salt-stable mutant revealed that the softening was not strictly coupled to the swelling of the protein shells. Our data suggest that a pH increase and Ca2+ chelation lead primarily to a loosening of contacts within the protein shell, resulting in a softening of the capsid. This appears to render the shell metastable and make swelling possible when repulsive forces among the capsid proteins become large enough, which is known to be followed by capsid disassembly at even higher pH. Thus, softening and swelling are likely to play a role during inoculation. PMID:25992732

  18. Swelling and softening of the cowpea chlorotic mottle virus in response to pH shifts.

    PubMed

    Wilts, Bodo D; Schaap, Iwan A T; Schmidt, Christoph F

    2015-05-19

    Cowpea chlorotic mottle virus (CCMV) forms highly elastic icosahedral protein capsids that undergo a characteristic swelling transition when the pH is raised from 5 to 7. Here, we performed nano-indentation experiments using an atomic force microscope to track capsid swelling and measure the shells' Young's modulus at the same time. When we chelated Ca(2+) ions and raised the pH, we observed a gradual swelling of the RNA-filled capsids accompanied by a softening of the shell. Control experiments with empty wild-type virus and a salt-stable mutant revealed that the softening was not strictly coupled to the swelling of the protein shells. Our data suggest that a pH increase and Ca(2+) chelation lead primarily to a loosening of contacts within the protein shell, resulting in a softening of the capsid. This appears to render the shell metastable and make swelling possible when repulsive forces among the capsid proteins become large enough, which is known to be followed by capsid disassembly at even higher pH. Thus, softening and swelling are likely to play a role during inoculation.

  19. Theoretical basis for an anomalous temperature coefficient in swelling pressure of rabbit corneal stroma.

    PubMed Central

    Kwok, L S; Klyce, S D

    1990-01-01

    In the rabbit corneal stroma, the swelling pressure, P, has been reported to have an anomalous (negative) temperature coefficient, alpha P, contradicting traditional Donnan swelling theory. A parallel-plate, diffuse double layer Gouy-Chapman model was used to resolve this discrepancy. The present model incorporates the possibility that surface charge, sigma, is temperature dependent. It is shown that negative, zero, or positive coefficients of swelling pressure change with temperature are not mutually exclusive conditions, but can be attributed to the same underlying mechanism. For likely values of alpha P(range -7 x 10(-3) K-1 to +3.2 x 10(-3)K-1), the effective stromal charge has a negative temperature dependency, or dln sigma/dT less than 0. The present formalism is robust against variation in assumed alpha P, and is able to simultaneously satisfy the known values of swelling pressure, its thermal dependency, and stromal charge. These results implicate significant coulombic forces behind P. Predicted stromal surface charge is approximately 0.01 Cm-2. The predictions were confirmed with macrocontinuum Donnan swelling theory, suggesting that Donnan osmotic swelling is the principal macroscopic component of P. PMID:2306510

  20. Does low-level laser therapy decrease swelling and pain resulting from orthognathic surgery?

    PubMed

    Gasperini, G; Rodrigues de Siqueira, I C; Rezende Costa, L

    2014-07-01

    Low-level laser therapy (LLLT) could be an alternative for the treatment of swelling and pain after orthognathic surgery, but there is a paucity of data in the literature on the effects of its use. This study verified the efficacy of an LLLT protocol to reduce swelling and pain after orthognathic surgery. Ten healthy patients who underwent a bilateral sagittal split with Le Fort I osteotomy were randomly selected for this study. The LLLT protocol consisted of intraoral and extraoral application to one side of the face after surgery (irradiated side); application to the other side was simulated (non-irradiated side). The irradiated and non-irradiated sides were compared regarding the swelling coefficient and were assessed for pain using a visual analogue scale. There were no significant differences between the irradiated and non-irradiated sides regarding swelling and pain in the immediate postoperative assessment. Swelling decreased significantly on the irradiated side in the postoperative assessments on days 3, 7, 15, and 30. Self-reported pain was less intense on the irradiated side at the 24-h (1.2 vs. 3.4) and 3-day (0.6 vs. 2.1) assessments, but at 7 days after surgery neither side showed pain. This LLLT protocol can improve the tissue response and reduce the pain and swelling resulting from orthognathic surgery.

  1. Size distribution of black spot defects and their contribution to swelling in irradiated SiC

    NASA Astrophysics Data System (ADS)

    Tyburska-Püschel, B.; Zhai, Y.; He, L.; Liu, C.; Boulle, A.; Voyles, P. M.; Szlufarska, I.; Sridharan, K.

    2016-08-01

    Experimental and modeling efforts were combined to investigate the role of black spot defects (BSD) in swelling of carbon- and krypton-irradiated 4H-SiC. Samples were exposed to conditions favoring BSD formation: irradiation at temperatures 600-950 °C and damage levels of 0.4-0.8 dpa. The maximum XRD swelling values, corrected for the effect of the rigid substrate, of 0.58% for C and 0.75% for Kr-irradiation were measured at the lowest irradiation temperature of 600 °C and decreased with increasing temperature. The swelling values estimated from TEM are on the same order of magnitude, but usually 40-70% lower than those measured by XRD. The contribution of BSDs to the overall swelling is 62% and the remainder of the swelling is caused by isolated point defects. The obtained results contribute to understanding of what defect types account for swelling and how their concentration evolves with the irradiation temperature and damage level.

  2. Study of equilibrium properties of Cr(III)/polyacrylamide gels by swelling measurement and equilibrium dialysis

    SciTech Connect

    Young, T.S.; Hunt, J.A.; Green, D.W.; Willhite, G.P. )

    1989-08-01

    In observations of the long-term properties of a series of Cr(III)/polyacrylamide (PAAM) gels, the gels either underwent syneresis upon aging or swelled in contact with excess brine. Both syneresis and swelling can substantially change the volume and properties of a gel placed in a formation and therefore influence the effectiveness of a crosslinked-polymer treatment. Efforts were made to develop an understanding of these phenomena and to describe them in terms of the gel's physical and chemical states. A long-term gel's physical and chemical states are characterized by two parameters, effective crosslinking density and chromium density, determined by equilibrium swelling and equilibrium dialysis, respectively. Swelling and syneresis properties were correlated to the effective cross-linking density described in polymer network theory. A model based on Flory and Hermans' swelling equations was developed to calculate the effective crosslinking densities of gels prepared from solution. Attempts were made to relate the swelling and syneresis properties to the compositions of gel systems to allow prediction of long-term stability of a gel based on its composition. An analysis of the amount of chromium that reacted with the PAAM was made by successive equilibrium dialyses of the gel followed by chromium analyses of dialysates by atomic and visible absorptions.

  3. Influence of Water Content on the Mechanical Properties of an Argillaceous Swelling Rock

    NASA Astrophysics Data System (ADS)

    Vergara, Maximiliano R.; Triantafyllidis, Theodoros

    2016-07-01

    This work presents the results of an experimental investigation aimed to study the effect of water on the mechanical properties of a partially saturated argillaceous swelling rock. The mineralogical composition of the rock, in particular the portion of swelling clays, was determined with X-ray diffraction. The water retention curve was estimated using a dew-point potential meter and the swelling behavior of the studied rock was examined by unconfined and oedometric swelling tests. The influence of water on the rock mechanical properties was assessed by means of triaxial tests. The experimental results indicate a strong decrease of strength and stiffness with increasing saturation or decreasing suction. This occurs only within a certain range of saturation. Degradation of the rock properties can be expected for small increments in the water content within this range. At low suction and close to the air-entry value, the stiffness remained constant. As the rock desaturates, the strength and stiffness increase approaching constant values. For suction greater than about 76 MPa, low increase of strength and stiffness was observed. The specimens in the swelling tests reached a saturation degree of 70 % which corresponds to a decrease of strength and stiffness of approximately 80 %. Rock swelling occurring simultaneously with reduction of strength and stiffness, increases deformations and it is an important issue for the stability of excavations.

  4. Migrating Oligodendrocyte Progenitor Cells Swell Prior to Soma Dislocation

    PubMed Central

    Happel, Patrick; Möller, Kerstin; Schwering, Nina K.; Dietzel, Irmgard D.

    2013-01-01

    The migration of oligodendrocyte progenitor cells (OPCs) to the white matter is an indispensable requirement for an intact brain function. The mechanism of cell migration in general is not yet completely understood. Nevertheless, evidence is accumulating that besides the coordinated rearrangement of the cytoskeleton, a finetuned interplay of ion and water fluxes across the cell membrane is essential for cell migration. One part of a general hypothesis is that a local volume increase towards the direction of movement triggers a mechano-activated calcium influx that regulates various procedures at the rear end of a migrating cell. Here, we investigated cell volume changes of migrating OPCs using scanning ion conductance microscopy. We found that during accelerated migration OPCs undergo an increase in the frontal cell body volume. These findings are supplemented with time lapse calcium imaging data that hint an increase in calcium content the frontal part of the cell soma. PMID:23657670

  5. An in-situ nano-scale swelling-filling strategy to improve overall performance of Nafion membrane for direct methanol fuel cell application

    NASA Astrophysics Data System (ADS)

    Li, Jing; Fan, Kun; Cai, Weiwei; Ma, Liying; Xu, Guoxiao; Xu, Sen; Ma, Liang; Cheng, Hansong

    2016-11-01

    A novel in-situ nano-scale swelling-filling (SF) strategy is proposed to modify commercial Nafion membranes for performance enhancement of direct methanol fuel cells (DMFCs). A Nafion membrane was filled in-situ with proton conductive macromolecules (PCMs) in the swelling process of a Nafion membrane in a PCM solution. As a result, both proton conductivity and methanol-permeation resistivity of the SF-treated Naifion membrane was substantially improved with the selectivity nearly doubled compared to the original Nafion membrane. The mechanical strength of the optimal SF treated Nafion membrane was also enforced due to the strong interaction between the PCM fillers and the Nafion molecular chains. As a result, a DMFC equipped with the SF-treated membrane yielded a 33% higher maximum power density than that offered by the DMFC with the original Nafion membrane.

  6. Brain Power.

    ERIC Educational Resources Information Center

    Albrecht, Karl

    2002-01-01

    Reviews significant findings of recent brain research, including the concept of five minds: automatic, subconscious, practical, creative, and spiritual. Suggests approaches to training the brain that are related to this hierarchy of thinking. (JOW)

  7. Brain Basics

    MedlinePlus

    ... have been linked to many mental disorders, including autism , obsessive compulsive disorder (OCD) , schizophrenia , and depression . Brain ... studies show that brain growth in children with autism appears to peak early. And as they grow ...

  8. Brain components

    MedlinePlus

    ... 3 major components of the brain are the cerebrum, cerebellum, and brain stem. The cerebrum is divided into left and right hemispheres, each ... gray matter) is the outside portion of the cerebrum and provides us with functions associated with conscious ...

  9. Brain Diseases

    MedlinePlus

    The brain is the control center of the body. It controls thoughts, memory, speech, and movement. It regulates the function of many organs. When the brain is healthy, it works quickly and automatically. However, ...

  10. Brain abscess

    MedlinePlus

    Tunkel AR. Brain abscess. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice ... Philadelphia, PA: Elsevier Saunders; 2015:chap 92. Tunkel AR, Scheld WM. Brain abscess. In: Winn HR, ed. ...

  11. Multifaceted roles for astrocytes in spreading depolarization: A target for limiting spreading depolarization in acute brain injury?

    PubMed

    Seidel, Jessica L; Escartin, Carole; Ayata, Cenk; Bonvento, Gilles; Shuttleworth, C William

    2016-01-01

    Spreading depolarizations (SDs) are coordinated waves of synchronous depolarization, involving large numbers of neurons and astrocytes as they spread slowly through brain tissue. The recent identification of SDs as likely contributors to pathophysiology in human subjects has led to a significant increase in interest in SD mechanisms, and possible approaches to limit the numbers of SDs or their deleterious consequences in injured brain. Astrocytes regulate many events associated with SD. SD initiation and propagation is dependent on extracellular accumulation of K(+) and glutamate, both of which involve astrocytic clearance. SDs are extremely metabolically demanding events, and signaling through astrocyte networks is likely central to the dramatic increase in regional blood flow that accompanies SD in otherwise healthy tissues. Astrocytes may provide metabolic support to neurons following SD, and may provide a source of adenosine that inhibits neuronal activity following SD. It is also possible that astrocytes contribute to the pathophysiology of SD, as a consequence of excessive glutamate release, facilitation of NMDA receptor activation, brain edema due to astrocyte swelling, or disrupted coupling to appropriate vascular responses after SD. Direct or indirect evidence has accumulated implicating astrocytes in many of these responses, but much remains unknown about their specific contributions, especially in the context of injury. Conversion of astrocytes to a reactive phenotype is a prominent feature of injured brain, and recent work suggests that the different functional properties of reactive astrocytes could be targeted to limit SDs in pathophysiological conditions.

  12. Brain Aneurysm

    MedlinePlus

    A brain aneurysm is an abnormal bulge or "ballooning" in the wall of an artery in the brain. They are sometimes called berry aneurysms because they ... often the size of a small berry. Most brain aneurysms produce no symptoms until they become large, ...

  13. Neuroprotection of Selective Brain Cooling After Penetrating Ballistic-like Brain Injury in Rats.

    PubMed

    Wei, Guo; Lu, Xi-Chun M; Shear, Deborah A; Yang, Xiaofang; Tortella, Frank C

    2011-01-01

    Induced hypothermia has been reported to provide neuroprotection against traumatic brain injury. We recently developed a novel method of selective brain cooling (SBC) and demonstrated its safety and neuroprotection efficacy in a rat model of ischemic brain injury. The primary focus of the current study was to evaluate the potential neuroprotective efficacy of SBC in a rat model of penetrating ballistic-like brain injury (PBBI) with a particular focus on the acute cerebral pathophysiology, neurofunction, and cognition. SBC (34°C) was induced immediately after PBBI, and maintained for 2 hours, followed by a spontaneous re-warming. Intracranial pressure (ICP) and regional cerebral blood flow were monitored continuously for 3 hours, and the ICP was measured again at 24 hours postinjury. Brain swelling, blood-brain barrier permeability, intracerebral hemorrhage, lesion size, and neurological status were assessed at 24 hours postinjury. Cognitive abilities were evaluated in a Morris water maze task at 12-16 days postinjury. Results showed that SBC significantly attenuated PBBI-induced elevation of ICP (PBBI = 33.2 ± 10.4; PBBI + SBC = 18.8 ± 6.7 mmHg) and reduced brain swelling, blood-brain barrier leakage, intracerebral hemorrhage, and lesion volume by 40%-45% for each matrix, and significantly improved neurologic function. However, these acute neuroprotective benefits of SBC did not translate into improved cognitive performance in the Morris water maze task. These results indicate that 34°C SBC is effective in protecting against acute brain damage and related neurological dysfunction. Further studies are required to establish the optimal treatment conditions (i.e., duration of cooling and/or combined therapeutic approaches) needed to achieve significant neurocognitive benefits.

  14. Subacute brain atrophy after radiation therapy for malignant brain tumor

    SciTech Connect

    Asai, A.; Matsutani, M.; Kohno, T.; Nakamura, O.; Tanaka, H.; Fujimaki, T.; Funada, N.; Matsuda, T.; Nagata, K.; Takakura, K.

    1989-05-15

    Brain atrophy with mental and neurologic deterioration developing a few months after radiation therapy in patients without residual or recurrent brain tumors has been recognized. Two illustrative case reports of this pathologic entity are presented. Six autopsy cases with this entity including the two cases were reviewed neurologically, radiographically, and histopathologically. All patients presented progressive disturbances of mental status and consciousness, akinesia, and tremor-like involuntary movement. Computerized tomography (CT) demonstrated marked enlargement of the ventricles, moderate widening of the cortical sulci, and a moderately attenuated CT number for the white matter in all six patients. Four of the six patients had CSF drainage (ventriculoperitoneal shunt or continuous lumbar drainage), however, none of them improved. Histologic examination demonstrated swelling and loss of the myelin sheath in the white matter in all patients, and reactive astrocytosis in three of the six patients. Neither prominent neuronal loss in the cerebral cortex or basal ganglia, nor axonal loss in the white matter was generally identified. The blood vessels of the cerebral cortex and white matter were normal. Ependymal layer and the surrounding brain tissue were normal in all patients. These findings suggested that this pathologic condition results from demyelination secondary to direct neurotoxic effect of irradiation. The authors' previous report was reviewed and the differential diagnoses, the risk factors for this pathologic entity, and the indication for radiation therapy in aged patients with a malignant brain tumor are discussed.

  15. [Species Determination and Spectral Characteristics of Swelling Clay Minerals in the Pliocene Sandstones in Xinghai, Qinghai].

    PubMed

    Wang, Chao-wen; Chen, Jiang-jun; Fang, Qian; Yin, Ke; Hong, Han-lie

    2015-10-01

    X-ray diffraction (XRD) and Fourier infrared absorption spectroscopy (FTIR) were conducted to deepen our research on specific species and spectral characteristics of swelling clay minerals in the Pliocene sandstones in Xinghai, Qinghai province. XRD results show that swelling clay minerals are dominant clay minerals in the sandstones, which can be up to 97% in percentage. XRD patterns show 060 reflections of the samples occur both remarkably at 1.534 Å and 1.498 Å, indicating the samples contain physical mixtures of trioctahedral and dioctahedral swelling clay minerals, respectively. Further treatment of Li-300 degrees C heat and glycerol saturation shows the swelling clay minerals collapse to 9.3-9.9 Å with a partial expansion to -18 Å. This indicates the swelling clay minerals dominate montmorillonite and contain minor saponite. The montmorillonite shows no swelling after Li-300 degrees C heat and glycerol saturation because of Li+ inserting into the octahedral layers, which balances the layer charge caused by the substitution of Mg to Al. FTIR results show the samples are composed of a kind of phyllosilicate with absorbed and structural water, which is in agreement with the results of XRD. Absorbed peaks at 913, 842, 880 cm(-1), corresponding to OH associated with Al-Al, Al-Mg, and Al-Fe pairs, further indicates the minerals are dominant dioctahedron in structure. Meanwhile, absorbed peaks at 625 and 519 cm(-1), corresponding to coupled Si-O and Al-O-Si deformation, indicates parts of Si is replaced by Al in tetrahedron. The spectral characteristics of the samples are against the presence of beidellite and nontronite based on the results of XRD and FTIR, while demonstrating an,existence of montmorillonite. This study, to distinguish the specific species of swelling clay species in clay minerals, would be of great importance when using clay mineralogy to interpret provenance and climatic information.

  16. Modeling the controllable pH-responsive swelling and pore size of networked alginate based biomaterials.

    PubMed

    Chan, Ariel W; Neufeld, Ronald J

    2009-10-01

    Semisynthetic network alginate polymer (SNAP), synthesized by acetalization of linear alginate with di-aldehyde, is a pH-responsive tetrafunctionally linked 3D gel network, and has potential application in oral delivery of protein therapeutics and active biologicals, and as tissue bioscaffold for regenerative medicine. A constitutive polyelectrolyte gel model based on non-Gaussian polymer elasticity, Flory-Huggins liquid lattice theory, and non-ideal Donnan membrane equilibria was derived, to describe SNAP gel swelling in dilute and ionic solutions containing uni-univalent, uni-bivalent, bi-univalent or bi-bi-valent electrolyte solutions. Flory-Huggins interaction parameters as a function of ionic strength and characteristic ratio of alginates of various molecular weights were determined experimentally to numerically predict SNAP hydrogel swelling. SNAP hydrogel swells pronouncedly to 1000 times in dilute solution, compared to its compact polymer volume, while behaving as a neutral polymer with limited swelling in high ionic strength or low pH solutions. The derived model accurately describes the pH-responsive swelling of SNAP hydrogel in acid and alkaline solutions of wide range of ionic strength. The pore sizes of the synthesized SNAP hydrogels of various crosslink densities were estimated from the derived model to be in the range of 30-450 nm which were comparable to that measured by thermoporometry, and diffusion of bovine serum albumin. The derived equilibrium swelling model can characterize hydrogel structure such as molecular weight between crosslinks and crosslinking density, or can be used as predictive model for swelling, pore size and mechanical properties if gel structural information is known, and can potentially be applied to other point-link network polyelectrolytes such as hyaluronic acid gel.

  17. Swelling induced by alpha decay in monazite and zirconolite ceramics: A XRD and TEM comparative study

    NASA Astrophysics Data System (ADS)

    Deschanels, X.; Seydoux-Guillaume, A. M.; Magnin, V.; Mesbah, A.; Tribet, M.; Moloney, M. P.; Serruys, Y.; Peuget, S.

    2014-05-01

    Zirconolite and monazite matrices are potential ceramics for the containment of actinides (Np, Cm, Am, Pu) which are produced over the reprocessing of spent nuclear fuel. Actinides decay mainly through the emission of alpha particles, which in turn causes most ceramics to undergo structural and textural changes (amorphization and/or swelling). In order to study the effects of alpha decays on the above mentioned ceramics two parallel approaches were set up. The first involved the use of an external irradiation source, Au, which allowed the deposited recoil energy to be simulated. The second was based on short-lived actinide doping with 238Pu, (i.e. an internal source), via the incorporation of plutonium oxide into both the monazite and zirconolite structures during synthesis. In both types of irradiation experiments, the zirconolite samples became amorphous at room temperature with damage close to 0.3 dpa; corresponding to a critical dose of 4 × 1018 α g-1 (i.e. ∼1.3 × 1021 keV cm-3). Both zirconolite samples also showed the same degree of macroscopic swelling at saturation (∼6%), with ballistic processes being the predominant damaging effect. In the case of the monazite however, the macroscopic swelling and amorphization were dependent on the nature of the irradiation. Externally, (Au), irradiated samples became amorphous while also demonstrating a saturation swelling of up to 8%. In contrast to this, the swelling of the 238Pu doped samples was much smaller at ∼1%. Also, unlike the externally (Au) irradiated monazite these 238Pu doped samples remained crystalline up to 7.5 × 1018 α g-1 (0.8 dpa). XRD, TEM and swelling measurements were used to fully characterize and interpret this behavior. The low swelling and the conservation of the crystalline state of 238Pu doped monazite samples indicates that alpha annealing took place within this material.

  18. Brain Basics: Know Your Brain

    MedlinePlus

    ... fact sheet is a basic introduction to the human brain. It may help you understand how the healthy ... largest and most highly developed part of the human brain: it consists primarily of the cerebrum ( 2 ) and ...

  19. Swell effect correction for the high-resolution marine seismic data acquired using an airgun and an 8-channel streamer cable

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Young; Koo, Nam-Hyung; Kim, Wonsik; Kim, Byoung-yeop; Cheong, Snons; Kim, Young-Jun

    2015-04-01

    High-resolution marine seismic surveys are used for the imaging of the detailed subsurface geological structure in engineering and marine geological survey. When the sea state gets worse, the quality of the seismic data become worse due to the sea swell. We corrected the swell effect to enhance the quality of seismic data. To remove the swell effect, we picked the sea bottom location automatically, averaged the picked sea bottom times of the adjacent traces and corrected the differences between the calculated and averaged sea bottom location. To make high quality seismic section, we used high-resolution marine 8-channel airgun seismic data acquired off Yeosu, Korea. The energy source was a 30 in3 airgun and the receiver was a 40 m long 8 channel streamer cable with a group interval of 5 m. The offset distance between the source and the first channel was 20 m. The shot interval was 2 seconds corresponding to ~5 m in distance, assuming ship's speed 5 knots. The data were digitally recorded with a sample interval of 0.1 ms and a record length of 1 s. The processing sequence includes basic processing procedures such as gain recovery, deconvolution, frequency filtering, CMP sorting, NMO correction, swell effect correction and stacking. To select sea bottom location for the swell effect correction, we pick maximum amplitude within the expected range including sea bottom location and find the first location at which the amplitude is larger than the threshold that is 40% of the maximum amplitude. We averaged these two-way travel times of sea bottom and corrected the differences. The range of the swell effect correction was -0.5 ~ 0.4 ms. After correction the continuity of reflectors were improved and high quality of the seismic data was produced. This study is a part of a Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (KIGAM), a National Research Laboratory (NRL) project supported by the Ministry of Science and Technology (MOST), and

  20. An upscaling method and a numerical analysis of swelling/shrinking processes in a compacted bentonite/sand mixture

    NASA Astrophysics Data System (ADS)

    Xie, M.; Agus, S. S.; Schanz, T.; Kolditz, O.

    2004-12-01

    This paper presents an upscaling concept of swelling/shrinking processes of a compacted bentonite/sand mixture, which also applies to swelling of porous media in general. A constitutive approach for highly compacted bentonite/sand mixture is developed accordingly. The concept is based on the diffuse double layer theory and connects microstructural properties of the bentonite as well as chemical properties of the pore fluid with swelling potential. Main factors influencing the swelling potential of bentonite, i.e. variation of water content, dry density, chemical composition of pore fluid, as well as the microstructures and the amount of swelling minerals are taken into account. According to the proposed model, porosity is divided into interparticle and interlayer porosity. Swelling is the potential of interlayer porosity increase, which reveals itself as volume change in the case of free expansion, or turns to be swelling pressure in the case of constrained swelling. The constitutive equations for swelling/shrinking are implemented in the software GeoSys/RockFlow as a new chemo-hydro-mechanical model, which is able to simulate isothermal multiphase flow in bentonite. Details of the mathematical and numerical multiphase flow formulations, as well as the code implementation are described. The proposed model is verified using experimental data of tests on a highly compacted bentonite/sand mixture. Comparison of the 1D modelling results with the experimental data evidences the capability of the proposed model to satisfactorily predict free swelling of the material under investigation. Copyright