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Sample records for brain swelling due

  1. 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

  2. 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

  3. Apnoea and brain swelling in non-accidental head injury

    PubMed Central

    Kemp, A; Stoodley, N; Cobley, C; Coles, L; Kemp, K; Geddes, J

    2003-01-01

    Aims: (1) To identify whether infants and young children admitted to hospital with subdural haematomas (SDH) secondary to non-accidental head injury (NAHI), suffer from apnoea leading to radiological evidence of hypoxic ischaemic brain damage, and whether this is related to a poor prognosis; and (2) to determine what degree of trauma is associated with NAHI. Methods: Retrospective case series (1992–98) with case control analysis of 65 children under 2 years old, with an SDH secondary to NAHI. Outcome measures were presenting symptoms, associated injuries and apnoea at presentation, brain swelling or hypoxic ischaemic changes on neuroimaging, and clinical outcome (KOSCHI). Results: Twenty two children had a history of apnoea at presentation to hospital. Apnoea was significantly associated with hypoxic ischaemic brain damage. Severe symptoms at presentation, apnoea, and diffuse brain swelling/hypoxic ischaemic damage were significantly associated with a poor prognosis. Eighty five per cent of cases had associated injuries consistent with a diagnosis of non-accidental injury. Conclusions: Coma at presentation, apnoea, and diffuse brain swelling or hypoxic ischaemia all predict a poor outcome in an infant who has suffered from SDH after NAHI. There is evidence of associated violence in the majority of infants with NAHI. At this point in time we do not know the minimum forces necessary to cause NAHI. It is clear however that it is never acceptable to shake a baby. PMID:12765909

  4. 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.

  5. 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

  6. Sulfonylurea receptor 1 contributes to the astrocyte swelling and brain edema in acute liver failure.

    PubMed

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

    2014-02-01

    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, nonselective cation (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 threefold 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 cotreatment 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.

  7. [The effect of fenibut on the ultrastructure of the brain mitochondria in traumatic edema and swelling].

    PubMed

    Novikov, V E; Naperstnikov, V V

    1994-01-01

    Rat experiments using electron microscopy have established that profound destructive changes occur in the mitochondria in the intra- and perifocal traumatic area in dynamics of traumatic edema-swelling. With phenibut, 50 mg/kg, there is an increase in the number of mitochondria in the brain tissue of the perifocal area, their destructive changes are less pronounced. It is assumed that the positive effect of phenibut on brain bioenergetic processes in the posttraumatic period is associated with the changes.

  8. 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.

  9. Penis swelling due to foreign body reaction after injection of silicone.

    PubMed

    Plaza, Tobias; Lautenschlager, Stephan

    2010-09-01

    A 19-year-old man presented with phimosis and painful swelling of the penis four weeks after augmentation with silicone in Thailand. Histology revealed a foreign body reaction to silicone. Infectious causes were ruled out. Granulomatous foreign body reactions to silicone are common, but there are few case reports on reactions following silicone injection for penis enlargement. Foreign body reactions should be included in the differential diagnosis of penis swelling.

  10. 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.

  11. 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

  12. “Caught by the Eye of Sound” – Epigastric Swelling due to Xiphisternal Tuberculosis

    PubMed Central

    Grover, Shabnam Bhandari; Arora, Sumit; Kumar, Amit; Grover, Hemal; Katyan, Amit; Nair, Deepthi Mohan

    2017-01-01

    Summary Background Common causes of an epigastric mass include hepatomegaly, pancreatic pseudocyst and epigastric hernia, less common causes being carcinoma of the stomach or pancreas, whereas diseases of the sternum presenting as an epigastric swelling is extremely uncommon. We report a case of tubercular infection of the sternum located in the xiphoid process resulting in its presentation as an epigastric swelling. Case Report A 30-year-old immunocompetent woman with complaints of an epigastric swelling and undocumented pyrexia for four months was referred for sonographic evaluation with a clinical suspicion of an incompletely treated liver abscess. The patient was examined with ultrasound, sternal radiographs, CT and MRI. Ultrasound revealed a heterogeneous epigastric collection with linear echogenic components suggestive of bone fragments. These appearances suggested chronic infective osteomyelitis of the xiphoid process of the sternum. Lateral chest radiograph demonstrated lytic destruction of the xiphisternum. Tubercular etiology was considered and further evaluation with Multidetector Computed tomography (MDCT) and Magnetic Resonance Imaging (MRI) demonstrated erosive osteomyelitis of the xiphoid process with enhancing inflammation and collection in the adjoining soft tissue. Ultrasound-guided aspiration, PCR and Amplified Mycobacterium tuberculosis DNA test confirmed tubercular infection. Conclusions We report a new case of osteo-articular tuberculosis localized to the xiphisternum, a rare clinical entity with an extremely unusual clinical presentation as an epigastric mass. The role of ultrasound in primary diagnosis and as an interventional diagnostic modality for guided aspiration is highlighted. PMID:28217237

  13. 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.

  14. 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

  15. Modification of SRIM-calculated dose and injected ion profiles due to sputtering, injected ion buildup and void swelling

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Toloczko, Mychailo B.; Bailey, Nathan; Garner, Frank A.; Gigax, Jonathan; Shao, Lin

    2016-11-01

    In radiation effects on materials utilizing self-ion irradiations, it is necessary to calculate the local displacement damage level and ion injection profile because of the short distance that self-ions travel in a material and because of the strong variation of displacement rate with depth in a specimen. The most frequently used tool for this is the software package called Stopping and Range of Ions in Matter (SRIM). A SRIM-calculated depth-dependent dose level is usually determined under the implicit assumption that the target does not undergo any significant changes in volume during the process, in particular SRIM ignores the effect of sputtering, injected ions, and void swelling on the redistribution of the dose and injected ion profiles. This approach become increasingly invalid as the ion fluence reaches ever higher levels, especially for low energy ion irradiations. The original surface is not maintained due to sputter-induced erosion, while within the irradiated region of the specimen, injected ions are adding material, and if void swelling is occurring, it is creating empty space. An iterative mathematical treatment of SRIM outputs to produce corrected dose and injected ion profiles based on these phenomenon and without regard to diffusion is presented along with examples of differences between SRIM-calculated values and corrected values over a range of typical ion energies. The intent is to provide the reader with a convenient tool for more accurately calculating dose and injected ion profiles for heavy-ion irradiations.

  16. Modification of SRIM-calculated dose and injected ion profiles due to sputtering, injected ion buildup and void swelling

    SciTech Connect

    Wang, Jing; Toloczko, Mychailo B.; Bailey, Nathan; Garner, Frank A.; Gigax, Jonathan; Shao, Lin

    2016-11-01

    In radiation effects on materials utilizing self-ion irradiations, it is necessary to calculate the local displacement damage level and ion injection profile because of the short distance that self-ions travel in a material and because of the strong variation of displacement rate with depth in a specimen. The most frequently used tool for this is the software package called Stopping and Range of Ions in Matter (SRIM). A SRIM-calculated depth-dependent dose level is usually determined under the implicit assumption that the target does not undergo any significant changes in volume during the process, in particular SRIM ignores the effect of sputtering, injected ions, and void swelling on the redistribution of the dose and injected atom profiles. This approach become increasingly invalid as the ion fluence reaches ever higher levels, especially for low energy ion irradiations. The original surface is not maintained due to sputter-induced erosion, while within the irradiated region of the specimen, injected ions are adding material, and if void swelling is occurring, it is creating empty space. An iterative mathematical treatment of SRIM outputs to produce corrected dose and injected atom profiles is presented along with examples differences between SRIM-calculated values and corrected values over a range of typical ion energies.

  17. 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 ...

  18. Molecular Mechanisms Involved in Tissue Swelling due to Injury and due to Exposure to Low Temperature and Massive Water and Electrolyte Loss in Diarrheal Disorders.

    DTIC Science & Technology

    1981-06-01

    shrink and swell in hyper - and hypotonic solutions when the polymer water system is enclosed in a regular dialysis tubing which is fully permeable to...indicate that a polymer water system can shrink and swell in the same manner as the living cells when they are placed in hyper - or hypotonic solutions...cell water would be highly hypotonic . As a result the cell is expected to shrink in a+normal Ringer solution containing Na of a concen- tration equal

  19. Increased toll-like receptor 4 in cerebral endothelial cells contributes to the astrocyte swelling and brain edema in acute hepatic encephalopathy.

    PubMed

    Jayakumar, Arumugam R; Tong, Xiao Y; Curtis, Kevin M; Ruiz-Cordero, Roberto; Abreu, Maria T; Norenberg, Michael D

    2014-03-01

    Astrocyte swelling and the subsequent increase in intracranial pressure and brain herniation are major clinical consequences in patients with acute hepatic encephalopathy. We recently reported that conditioned media from brain endothelial cells (ECs) exposed to ammonia, a mixture of cytokines (CKs) or lipopolysaccharide (LPS), when added to astrocytes caused cell swelling. In this study, we investigated the possibility that ammonia and inflammatory agents activate the toll-like receptor 4 (TLR4) in ECs, resulting in the release of factors that ultimately cause astrocyte swelling. We found a significant increase in TLR4 protein expression when ECs were exposed to ammonia, CKs or LPS alone, while exposure of ECs to a combination of these agents potentiate such effects. In addition, astrocytes exposed to conditioned media from TLR4-silenced ECs that were treated with ammonia, CKs or LPS, resulted in a significant reduction in astrocyte swelling. TLR4 protein up-regulation was also detected in rat brain ECs after treatment with the liver toxin thioacetamide, and that thioacetamide-treated TLR4 knock-out mice exhibited a reduction in brain edema. These studies strongly suggest that ECs significantly contribute to the astrocyte swelling/brain edema in acute hepatic encephalopathy, likely as a consequence of increased TLR4 protein expression by blood-borne noxious agents.

  20. 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

    2015-06-04

    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.

  1. Leg Swelling

    MedlinePlus

    ... swelling. References Sterns RH. Pathophysiology and etiology of edema in adults. www.uptodate.com/home. Accessed Dec. 29, 2016. Edema. Merck Manual Professional Version. http://www.merckmanuals.com/ ...

  2. Selective vasopressin-1a receptor antagonist prevents brain edema, reduces astrocytic cell swelling and GFAP, V1aR and AQP4 expression after focal traumatic brain injury.

    PubMed

    Marmarou, Christina R; Liang, Xiuyin; Abidi, Naqeeb H; Parveen, Shanaz; Taya, Keisuke; Henderson, Scott C; Young, Harold F; Filippidis, Aristotelis S; Baumgarten, Clive M

    2014-09-18

    A secondary and often lethal consequence of traumatic brain injury is cellular edema that we posit is due to astrocytic swelling caused by transmembrane water fluxes augmented by vasopressin-regulated aquaporin-4 (AQP4). We therefore tested whether vasopressin 1a receptor (V1aR) inhibition would suppress astrocyte AQP4, reduce astrocytic edema, and thereby diminish TBI-induced edematous changes. V1aR inhibition by SR49059 significantly reduced brain edema after cortical contusion injury (CCI) in rat 5h post-injury. Injured-hemisphere brain water content (n=6 animals/group) and astrocytic area (n=3/group) were significantly higher in CCI-vehicle (80.5±0.3%; 18.0±1.4 µm(2)) versus sham groups (78.3±0.1%; 9.5±0.9 µm(2)), and SR49059 blunted CCI-induced increases in brain edema (79.0±0.2%; 9.4±0.8µm(2)). CCI significantly up-regulated GFAP, V1aR and AQP4 protein levels and SR49059 suppressed injury induced up regulation (n=6/group). In CCI-vehicle, sham and CCI-SR49059 groups, GFAP was 1.58±0.04, 0.47±0.02, and 0.81±0.03, respectively; V1aR was 1.00±0.06, 0.45±0.05, and 0.46±0.09; and AQP4 was 2.03±0.34, 0.49±0.04, and 0.92±0.22. Confocal immunohistochemistry gave analogous results. In CCI-vehicle, sham and CCI-SR49059 groups, fluorescence intensity of GFAP was 349±38, 56±5, and 244±30, respectively, V1aR was 601±71, 117.8±14, and 390±76, and AQP4 was 818±117, 158±5, and 458±55 (n=3/group). The results support that edema was predominantly cellular following CCI and documented that V1aR inhibition with SR49059 suppressed injury-induced up regulation of GFAP, V1A and AQP4, blunting edematous changes. Our findings suggest V1aR inhibitors may be potential therapeutic tools to prevent cellular swelling and provide treatment for post-traumatic brain edema.

  3. Brain abscess due to odontogenic infection: a case report

    PubMed Central

    Park, Sung Yong; Suh, Dong Won; Park, Chul Min; Oh, Min Seok

    2014-01-01

    In this report, we describe a case of brain abscess due to odontogenic infection. A 53-year-old female who had been suffering from headache and trismus for two weeks visited the Department of Oral and Maxillofacial Surgery at the Sun Dental Hospital (Daejeon, Korea). Even after several routine tests, we still could not make a diagnosis. However, after the combined multidisciplinary efforts of oral surgeons and neurosurgeons, the patient was treated for odontogenic infection and made an uneventful recovery. Therefore, patients with infections in the head and neck region showing symptoms such as headache, changes in mental state, nausea, vomiting, seizures, hemiplegia, speech disturbance, and visual disturbance, a brain abscess should be included in the list of differential diagnoses. PMID:25045643

  4. Deep brain stimulation in addiction due to psychoactive substance use.

    PubMed

    Kuhn, Jens; Bührle, Christian P; Lenartz, Doris; Sturm, Volker

    2013-01-01

    Addiction is one of the most challenging health problems. It is associated with enormous individual distress and tremendous socioeconomic consequences. Unfortunately, its underlying mechanisms are not fully understood, and pharmacological, psychological, or social interventions often fail to achieve long-lasting remission. Next to genetic, social, and contextual factors, a substance-induced dysfunction of the brain's reward system is considered a decisive factor for the establishment and maintenance of addiction. Due to its successful application and approval for several neurological disorders, deep brain stimulation (DBS) is known as a powerful tool for modulating dysregulated networks and has also been considered for substance addiction. Initial promising case reports of DBS in alcohol and heroin addiction in humans have recently been published. Likewise, results from animal studies mimicking different kinds of substance addiction point in a similar direction. The objective of this review is to provide an overview of the published results on DBS in addiction, and to discuss whether these preliminary results justify further research, given the novelty of this treatment approach.

  5. Extravascular compression of the femoral vein due to wear debris-induced iliopsoas bursitis: a rare cause of leg swelling after total hip arthroplasty.

    PubMed

    Beksaç, Burak; Tözün, Remzi; Baktiroglu, Selcuk; Sener, Nadir; Gonzalez Della Valle, Alejandro

    2007-04-01

    We present a patient with unilateral, spontaneous, late leg swelling that developed 4 years after total hip arthroplasty. The etiology was the compression of the internal iliac vein by a voluminous iliopsoas bursitis caused by polyethylene debris. The expansive lesion was detected by ultrasound, arthrography, and magnetic resonance imaging. An ultrasound-guided aspiration provided transient relief of the patient's symptoms. The patient later required surgical excision through an abdominal approach. A second recurrence was detected and treated with revision surgery. We present the diagnosis and the treatment of this rare cause of late, unilateral leg swelling after total hip arthroplasty together with a review of the literature.

  6. 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 ...

  7. 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.

  8. Cinnamon polyphenols attenuate cell swelling and mitochondrial dysfunction following oxygen-glucose deprivation in glial cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Astrocyte swelling is an integral component of cytotoxic brain edema in ischemic injury. While mechanisms underlying astrocyte swelling are likely multifactorial, oxidative stress and mitochondrial dysfunction are hypothesized to contribute to such swelling. We investigated the protective effects of...

  9. Targeting Epigenetic Mechanisms in Pain Due to Trauma and Traumatic Brain Injury (TBI)

    DTIC Science & Technology

    2015-10-01

    brain or peripheral trauma may support chronic pain. Our work to-date has established a rodent model of TBI in combination with injury to a limb as a...AWARD NUMBER: W81XWH-14-1-0579 TITLE: Targeting Epigenetic Mechanisms in Pain due to Trauma and Traumatic Brain Injury (TBI) PRINCIPAL...SUBTITLE Targeting Epigenetic Mechanisms in Pain due to Trauma and Traumatic Brain Injury (TBI) 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-14-1-0579 5c

  10. Decreased STAT3 Phosphorylation Mediates Cell Swelling in Ammonia-Treated Astrocyte Cultures

    PubMed Central

    Jayakumar, Arumugam R.; Curtis, Kevin M.; Panickar, Kiran S.; Shamaladevi, Nagarajarao; Norenberg, Michael D.

    2016-01-01

    Brain edema, due largely to astrocyte swelling, and the subsequent increase in intracranial pressure and brain herniation, are major complications of acute liver failure (ALF). Elevated level of brain ammonia has been strongly implicated in the development of astrocyte swelling associated with ALF. The means by which ammonia brings about astrocyte swelling, however, is incompletely understood. Recently, oxidative/nitrosative stress and associated signaling events, including activation of mitogen-activated protein kinases (MAPKs), as well as activation of the transcription factor, nuclear factor-kappaB (NF-κB), have been implicated in the mechanism of ammonia-induced astrocyte swelling. Since these signaling events are known to be regulated by the transcription factor, signal transducer and activator of transcription 3 (STAT3), we examined the state of STAT3 activation in ammonia-treated cultured astrocytes, and determined whether altered STAT3 activation and/or protein expression contribute to the ammonia-induced astrocyte swelling. STAT3 was found to be dephosphorylated (inactivated) at Tyrosine705 in ammonia-treated cultured astrocytes. Total STAT3 protein level was also reduced in ammonia-treated astrocytes. We also found a significant increase in protein tyrosine phosphatase receptor type-1 (PTPRT-1) protein expression in ammonia-treated cultured astrocytes, and that inhibition of PTPRT-1 enhanced the phosphorylation of STAT3 after ammonia treatment. Additionally, exposure of cultured astrocytes to inhibitors of protein tyrosine phosphatases diminished the ammonia-induced cell swelling, while cultured astrocytes over-expressing STAT3 showed a reduction in the astrocyte swelling induced by ammonia. Collectively, these studies strongly suggest that inactivation of STAT3 represents a critical event in the mechanism of the astrocyte swelling associated with acute liver failure. PMID:27918421

  11. 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.

  12. 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.

  13. [Three cases of brain injury due to windshield impact (author's transl)].

    PubMed

    Isu, T; Abe, H; Aida, T; Iwakuma, T

    1979-04-01

    Three cases of brain injury due to windshield impact (tempered windshield) were reported. In the case of brain injury, multitude of small cracks injured the frontal lobe through the orbital roof with facial injuries due to windshield impact. Though we are apt to misdiagnose because of very small wounds, the diagnosis can be made easily from the plain film. The craniotomy, with complete removal of glass fragments and dural plasty, must be performed for the purpose of preventing infection and cerebrospinal fluid rhinorrhea. We believe that the use of seat belt and H.P.R. type laminated windshield is the best precaution against the windshield impact.

  14. Activation of the ACE2/Ang-(1-7)/Mas pathway reduces oxygen-glucose deprivation induced tissue swelling, ROS production, and cell death in mouse brain with angiotensin II overproduction

    PubMed Central

    Zheng, Jiaolin; Li, Guangze; Chen, Shuzhen; Chen, Ji; Buck, Joshua; Zhu, Yulan; Xia, Huijing; Lazartigues, Eric; Chen, Yanfang; Olson, James E.

    2014-01-01

    We previously demonstrated that mice which overexpress human renin and angiotensinogen (R+A+) show enhanced cerebral damage in both in vivo and in vitro experimental ischemia models. Angiotensin converting enzyme 2 (ACE2) counteracts the effects of angiotensin (Ang-II) by transforming it into Ang-(1-7), thus reducing the ligand for the AT1 receptor and increasing stimulation of the Mas receptor. Triple transgenic mice, SARA, which specifically overexpress ACE2 in neurons of R+A+ mice were used to study the role of ACE2 in ischemic stroke using oxygen and glucose deprivation (OGD) of brain slices as an in vitro model. We examined tissue swelling, the production of reactive oxygen species (ROS), and cell death in cerebral cortex (CX) and the hippocampal CA1 region during OGD. Expression levels of NADPH oxidase isoforms, Nox2 and Nox4 were measured using western blots. Results show that SARA mice and R+A+ mice treated with the Mas receptor agonist Ang-(1-7) had less swelling, cell death, and ROS production in CX and CA1 areas compared to those in R+A+ animals. Treatment of slices from SARA mice with the Mas antagonist A779 eliminated this protection. Finally, western blots revealed less Nox2 and Nox4 expression in SARA mice compared with R+A+ mice both before and after OGD. We suggest that reduced brain swelling and cell death observed in SARA animals exposed to OGD results from diminished ROS production coupled with lower expression of NADPH oxidases. Thus, the ACE2/Ang-(1-7)/Mas receptor pathway plays a protective role in brain ischemic damage by counteracting the detrimental effects of Ang-II-induced ROS production. PMID:24814023

  15. [Brain abscess due to Fusobacterium necrophorum in a patient with convulsion and no signs of meningitis].

    PubMed

    Shimohata, Mitsuteru; Naruse, Satoshi; Kawasaki, Satoshi; Watanabe, Yumiko; Koyama, Miyako; Ito, Yasushi; Tanaka, Hajime

    2012-01-01

    Here, we report brain abscess due to Fusobacterium necrophorum (F. necrophorum) in a 78-year-old healthy man. He developed convulsion and did not have any signs of meningitis. Although the brain magnetic resonance imaging findings of the left occipital lobe were typical of a brain abscess, his cerebrospinal fluid examination revealed only slight pleocytosis and mild increase in protein levels. Thus, it was difficult to rule out the possibility of metastatic brain tumor; the patient's condition was provisionally diagnosed as symptomatic epilepsy secondary to brain abscess. His convulsion disappeared soon after administration of antiepileptic, antibacterial, and steroid agents. A craniotomy was performed to evacuate the abscess, and F. necrophorum was identified by culturing the abscess contents. After the operation, he was treated with appropriate antibacterial agents, which resulted in resolution of the brain abscess. Although Fusobacterium species are gram-negative anaerobic bacilli commensal of the human oropharynx, we need to recognize that Fusobacterium species can be a primary pathogen causing brain abscesses and may leave residual neurological sequelae without early appropriate treatment.

  16. 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.

  17. 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.

  18. Foot, leg, and ankle swelling

    MedlinePlus

    ... feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... 51. Trayes KP, Studdiford JS, Pickle S, Tully AS. Edema: Diagnosis and management. Am Fam Phys . 2013;88( ...

  19. Infiltration in Swelling Soils

    NASA Astrophysics Data System (ADS)

    Giraldez, Juan V.; Sposito, Garrison

    1985-01-01

    Infiltration phenomena in swelling soils were investigated theoretically. The approach taken consisted of applying both the approximate analytical techniques developed by J.-Y. Parlange and co-workers and conventional finite difference numerical methods to study the generalized Richards equation for one-dimensional infiltration in a swelling soil. Equations were derived for the ponding time and the post-ponding infiltration rate that are generalizations of the Parlange-Smith model expressions for rigid soils. Ponding times for swelling soils were shown to be shorter than those for nonswelling analogs, and post-ponding infiltration rates in swelling soils were shown to approach zero instead of becoming equal to the hydraulic conductivity, as in rigid soils. These results were confirmed, both qualitatively and quantitatively, with the numerical model, which also provided instantaneous moisture profiles and surface swelling predictions in agreement with field observations. A three-parameter infiltration equation proposed recently by J.-Y. Parlange et al. (1982) was generalized to describe swelling soils and shown to be in good agreement with published laboratory and field data. It appears that the generalized analytical model equations developed can be employed conveniently in hydrologic applications which do not require high accuracy in predictions.

  20. Brain strain uncertainty due to shape variation in and simplification of head angular velocity profiles.

    PubMed

    Zhao, Wei; Ji, Songbai

    2017-04-01

    Head angular velocity, instead of acceleration, is more predictive of brain strains. Surprisingly, no study exists that investigates how shape variation in angular velocity profiles affects brain strains, beyond characteristics such as peak magnitude and impulse duration. In this study, we evaluated brain strain uncertainty due to variation in angular velocity profiles and further compared with that resulting from simplifying the profiles into idealized shapes. To do so, we used reconstructed head impacts from American National Football League for shape extraction and simulated head uniaxial coronal rotations from onset to full stop. The velocity profiles were scaled to maintain an identical peak velocity magnitude and duration in order to isolate the shape for investigation. Element-wise peak maximum principal strains from 44 selected impacts were obtained. We found that the shape of angular velocity profile could significantly affect brain strain magnitude (e.g., percentage difference of 4.29-17.89 % in the whole brain relative to the group average, with cumulative strain damage measure (CSDM) uncertainty range of 23.9 %) but not pattern (correlation coefficient of 0.94-0.99). Strain differences resulting from simplifying angular velocity profiles into idealized shapes were largely within the range due to shape variation, in both percentage difference and CSDM (signed difference of 3.91 % on average, with a typical range of 0-6 %). These findings provide important insight into the uncertainty or confidence in the performance of kinematics-based injury metrics. More importantly, they suggest the feasibility to simplify head angular velocity profiles into idealized shapes, at least within the confinements of the profiles evaluated, to enable real-time strain estimation via pre-computation in the future.

  1. Patterns in swelling hydrogels

    NASA Astrophysics Data System (ADS)

    MacMinn, Chris; Bertrand, Thibault; Peixinho, Jorge; Mukhopadhyay, Shomeek

    2016-11-01

    Swelling is a process in which a porous material spontaneously grows by absorbing additional pore fluid. Polymeric hydrogels are highly deformable materials that can experience very large volume changes during swelling. This allows a small amount of dry gel to absorb a large amount of fluid, making gels extremely useful in applications from moisture control to drug delivery. However, a well-known consequence of these extreme volume changes is the emergence of a striking morphological instability. We study the transient mechanics of this instability here by combining a theoretical model with a series of simple experiments, focusing on the extent to which this instability can be controlled by manipulating the rate of swelling.

  2. 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

  3. Psychotic disorder due to traumatic brain injury: analysis of case studies in the literature.

    PubMed

    Fujii, Daryl; Fujii, Daniel C

    2012-01-01

    The present study utilized methodology from a previous descriptive study that analyzed case studies of psychotic disorder due to traumatic brain injury (PD-TBI) reported in psychiatry and neurology journals. The purpose was to replicate findings from the PD-TBI literature and to elucidate a pattern of characteristics that would differentiate PD-TBI from schizophrenia. The findings supported both objectives. PD-TBI data were highly consistent with previous studies: PD-TBI differed from schizophrenia in showing more focal frontal and temporal abnormalities on neurological studies and a lower rate of negative symptoms. The authors discuss implications of these findings for conceptualizing psychosis as a neurobiological syndrome.

  4. 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 ...

  5. 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.

  6. 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

  7. Deficiency of p62/Sequestosome 1 causes hyperphagia due to leptin resistance in the brain.

    PubMed

    Harada, Harumi; Warabi, Eiji; Matsuki, Taizo; Yanagawa, Toru; Okada, Kosuke; Uwayama, Junya; Ikeda, Akira; Nakaso, Kazuhiro; Kirii, Kyoko; Noguchi, Noriko; Bukawa, Hiroki; Siow, Richard C M; Mann, Giovanni E; Shoda, Junichi; Ishii, Tetsuro; Sakurai, Takeshi

    2013-09-11

    The cytoplasmic regulatory protein p62 (Sequestosome 1/A170) is known to modulate various receptor-mediated intracellular signaling pathways. p62 deficiency was shown to result in mature-onset obesity in mice, but the mechanisms underlying this abnormality remained unclear. Here we report that hyperphagia due to central leptin resistance is the cause of obesity in p62(-/-) mice. We found that these mice show hyperphagia. Restriction of food to the amount eaten by wild-type mice prevented excess body weight gain and fat accumulation, suggesting that overfeeding is the primary cause of obesity in p62(-/-) mice. Brain-specific p62 deficiency caused mature-onset obesity to the same extent as in p62(-/-) mice, further supporting a neuronal mechanism as the major cause of obesity in these mice. Immunohistochemical analysis revealed that p62 is highly expressed in hypothalamic neurons, including POMC neurons in the arcuate nucleus. Central leptin resistance was observed even in young preobese p62(-/-) mice. We found a defect in intracellular distribution of the transcription factor Stat3, which is essential for the action of leptin, in p62(-/-) mice. These results indicate that brain p62 plays an important role in bodyweight control by modulating the central leptin-signaling pathway and that lack of p62 in the brain causes leptin resistance, leading to hyperphagia. Thus, p62 could be a clinical target for treating obesity and metabolic syndrome.

  8. [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.

  9. Swelling transition of a clay induced by heating

    PubMed Central

    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

  10. 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…

  11. 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

  12. Postoperative pectoral swelling after shoulder arthroscopy.

    PubMed

    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.

  13. Occurrence of spontaneous and audiogenic seizures following global brain ischaemia due to cardiac arrest.

    PubMed

    Ułamek-Kozioł, Marzena; Kocki, Janusz; Bogucka-Kocka, Anna; Januszewski, Sławomir; Czuczwar, Stanisław J; Pluta, Ryszard

    2015-01-01

    Transient cardiac arrest due to cardiac vessel bundle occlusion was used to produce a rat model of spontaneous and audiogenic seizures. Among the rats, spontaneous seizures were present in 64%, and audiogenic seizures could be evoked in 86%, during two weeks of survival after cardiac arrest, by exposure to a loud sound produced by rattling keys, beginning one day after the post-ischaemic injury. Data from literature suggested a key role for GABA-ergic system widespread dysfunction especially in the hippocampus in post-cardiac arrest onset of audiogenic seizures. Reduced GABA inhibition in the hippocampus seems responsible for audiogenic seizures following cardiac arrest. In summary it may be considered that the occurrence of audiogenic seizures following cardiac arrest is determined not only by a neuronal loss, especially in the hippocampus, but also by a condition of synapse modification by a regenerative phenomenon. Data from our study clearly indicate that global brain ischaemia due to cardiac arrest may induce the susceptibility to spontaneous and audiogenic seizures, but this effect is transient.

  14. 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.

  15. Brain-computer interface controlled functional electrical stimulation device for foot drop due to stroke.

    PubMed

    Do, An H; Wang, Po T; King, Christine E; Schombs, Andrew; Cramer, Steven C; Nenadic, Zoran

    2012-01-01

    Gait impairment due to foot drop is a common outcome of stroke, and current physiotherapy provides only limited restoration of gait function. Gait function can also be aided by orthoses, but these devices may be cumbersome and their benefits disappear upon removal. Hence, new neuro-rehabilitative therapies are being sought to generate permanent improvements in motor function beyond those of conventional physiotherapies through positive neural plasticity processes. Here, the authors describe an electroencephalogram (EEG) based brain-computer interface (BCI) controlled functional electrical stimulation (FES) system that enabled a stroke subject with foot drop to re-establish foot dorsiflexion. To this end, a prediction model was generated from EEG data collected as the subject alternated between periods of idling and attempted foot dorsiflexion. This prediction model was then used to classify online EEG data into either "idling" or "dorsiflexion" states, and this information was subsequently used to control an FES device to elicit effective foot dorsiflexion. The performance of the system was assessed in online sessions, where the subject was prompted by a computer to alternate between periods of idling and dorsiflexion. The subject demonstrated purposeful operation of the BCI-FES system, with an average cross-correlation between instructional cues and BCI-FES response of 0.60 over 3 sessions. In addition, analysis of the prediction model indicated that non-classical brain areas were activated in the process, suggesting post-stroke cortical re-organization. In the future, these systems may be explored as a potential therapeutic tool that can help promote positive plasticity and neural repair in chronic stroke patients.

  16. Neuronal and glial alterations due to focal cortical hypoxia induced by direct cobalt chloride (CoCl2) brain injection.

    PubMed

    Caltana, Laura; Merelli, Amalia; Lazarowski, Alberto; Brusco, Alicia

    2009-05-01

    Ischemic brain injury is a dynamic process that involves oxidative stress, inflammation, and cell death, as well as activation of endogenous adaptive and regenerative mechanisms depending on activation of transcription factors such as hypoxia inducible factor 1-alpha (HIF-1alpha). Because CoCl2 activates HIF-1alpha, we described a new focal-hypoxia model by direct intracerebral CoCl2 injection. Adult male Wistar rats were intracerebrally injected with CoCl2 (2 microl-50 mM), in frontoparietal cortex of right hemisphere, and saline (2 microl) in the contralateral hemisphere. In slides of fixed brains at 1, 6, 9, 24 h or 5 day after treatment, TTC, histochemistry (toluidine blue, Hoescht-33342, TUNEL), immunostaining (HIF-1alpha, GFAP), Lycopersicon esculentum lectin staining, and electron microscopy (EM) were performed. Immediately after 1 h post CoCl2 injection, HIF-1alpha stabilization and neuronal nuclear shrinkage and cromathin condensation were observed by immunostaining and EM, respectively. Neuronal apoptotic nuclear morphology and GFAP immunoreactivity and lectin maximal reactivity were detected during 6-9 h. Ultrastructural alterations of morphology included edematous perinuclear cytoplasm, organelles and endoplasmic reticulum (RE) enlargement, mitochondrial swelling with increased matrix density, and deposits of electron-dense material. Neurons showed particular nuclear indentations. Astrocytes and oligodendrocytes presented alterations in both nuclei and RE with dilated lumen and altered mitochondrias, and all these ultrastructural changes became detectable at day 5. CoCl2 cortical injection mimics focal brain ischemia, inducing neuronal death and glial activation. This model brings the opportunity to develop focal ischemia in selected brain areas to study their functional consequences and potential pharmacological therapies for in vivo models of stroke.

  17. 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

  18. Olanzapine and Betamethasone Are Effective for the Treatment of Nausea and Vomiting due to Metastatic Brain Tumors of Rectal Cancer

    PubMed Central

    Suzuki, M.; Komuro, K.; Ohara, K.

    2014-01-01

    Brain lesions originating from metastasis of colorectal cancer represent 3–5% of all brain metastases and are relatively rare. Of all distant metastases of colorectal cancer, those to the liver are detected in 22–29% of cases, while those to the lungs are detected in 8–18% of cases. In contrast, brain metastasis is quite rare, with a reported incidence ranging from 0.4 to 1.8%. Treatments for metastatic brain tumors include surgery, radiotherapy, chemotherapy and supportive care with steroids, etc. Untreated patients exhibit a median survival of only approximately 1 month. The choice of treatment for brain metastasis depends on the number of lesions, the patient's general condition, nerve findings and presence of other metastatic lesions. We herein report the case of a 78-year-old male who presented with brain metastases originating from rectal carcinoma. He suffered from nausea, vomiting, anorexia and vertigo during body movement. He received antiemetics, glycerol and whole brain radiation therapy; however, these treatments proved ineffective. Olanzapine therapy was started at a dose of 1.25 mg every night. The persistent nausea disappeared the next day, and the frequency of vomiting subsequently decreased. The patient was able to consume solid food. Olanzapine is an antipsychotic that has recently been used as palliative therapy for refractory nausea and vomiting in patients receiving chemotherapy. We consider that olanzapine was helpful as a means of supportive care for the treatment of nausea and vomiting due to brain metastasis. PMID:24574944

  19. Evaluation of linear registration algorithms for brain SPECT and the errors due to hypoperfusion lesions.

    PubMed

    Radau, P E; Slomka, P J; Julin, P; Svensson, L; Wahlund, L O

    2001-08-01

    The semiquantitative analysis of perfusion single-photon emission computed tomography (SPECT) images requires a reproducible, objective method. Automated spatial standardization (registration) of images is a prerequisite to this goal. A source of registration error is the presence of hypoperfusion defects, which was evaluated in this study with simulated lesions. The brain perfusion images measured by 99mTc-HMPAO SPECT from 21 patients with probable Alzheimer's disease and 35 control subjects were retrospectively analyzed. An automatic segmentation method was developed to remove external activity. Three registration methods, robust least squares, normalized mutual information (NMI), and count difference were implemented and the effects of simulated defects were compared. The tested registration methods required segmentation of the cerebrum from external activity, and the automatic and manual methods differed by a three-dimensional displacement of 1.4+/-1.1 mm. NMI registration proved to be least adversely effected by simulated defects with 3 mm average displacement caused by severe defects. The error in quantifying the patient-template parietal ratio due to misregistration was 2.0% for large defects (70% hypoperfusion) and 0.5% for smaller defects (85% hypoperfusion).

  20. 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.

  1. 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

  2. [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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

    The goal of this study is to investigate the impact of electroencephalogram (EEG) electrodes on the visual quality and quantification of 18F-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.

  4. Low-frequency dielectric dispersion of brain tissue due to electrically long neurites

    NASA Astrophysics Data System (ADS)

    Monai, Hiromu; Inoue, Masashi; Miyakawa, Hiroyoshi; Aonishi, Toru

    2012-12-01

    The dielectric properties of brain tissue are important for understanding how neural activity is related to local field potentials and electroencephalograms. It is known that the permittivity of brain tissue exhibits strong frequency dependence (dispersion) and that the permittivity is very large in the low-frequency region. However, little is known with regard to the cause of the large permittivity in the low-frequency region. Here, we postulate that the dielectric properties of brain tissue can be partially accounted for by assuming that neurites are of sufficient length to be “electrically long.” To test this idea, we consider a model in which a neurite is treated as a long, narrow body, and it is subjected to a stimulus created by electrodes situated in the region external to it. With regard to this electric stimulus, the neurite can be treated as a passive cable. Assuming adequate symmetry so that the tissue packed with multiple cables is equivalent to an isolated system consisting of a single cable and a surrounding extracellular resistive medium, we analytically calculate the extracellular potential of the tissue in response to such an externally created alternating-current electric field using a Green's function that we obtained previously. Our results show that brain tissue modeled by such a cable existing within a purely resistive extracellular medium exhibits a large effective permittivity in the low-frequency region. Moreover, we obtain results suggesting that an extremely large low-frequency permittivity can coexist with weak low-pass filter characteristics in brain tissue.

  5. 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

  6. Swelling/deswelling of Toroidal Hydrogels

    NASA Astrophysics Data System (ADS)

    Chang, Ya-Wen; Dimitriyev, Michael; Marquez, Samantha; Goldbart, Paul; Fernandez-Nieves, Alberto

    2014-03-01

    Swelling/deswelling of hydrogel spheres proceeds with the increase/decrease of particle radius that corresponds to the change in overall volume. When the hydrogel has a toroidal geometry, which is characterized by two principal radii -radius from the center of the donut hole to the center of the tube, and the tube radius, it is not obvious how swelling proceeds. We prepare thermo-sensitive poly(N-isopropylacrylamide) pNIPAM toroidal gel particles of different aspect ratios. At equilibrium deswelling, i.e., slow heating rate, we find that the aspect ratio remains constant for both fat and thin tori. This is explained by linear elasticity. On the other hand, when the heating rate is sufficiently high, the toroid buckles due to the presence of a water-impermeable skin layer that develops in the initial deswelling stages. Acknowledgement: We thank Dr. Manuel Marquez, YNano LLC for financial support

  7. Changes in Mice Brain Spontaneous Electrical Activity during Cortical Spreading Depression due to Mobile Phone Radiation

    PubMed Central

    Sallam, Samera M.; Mohamed, Ehab I.; Dawood, Abdel-Fattah B.

    2008-01-01

    The objective of the present study was to investigate changes in spontaneous EEG activity during cortical spreading depression (CSD) in mice brain. The cortical region of anaesthetized mice were exposed to the electromagnetic fields (EMFs) emitted from a mobile phone (MP, 935.2-960.2 MHz, 41.8 mW/cm2). The effect of EMFs on EEG was investigated before and after exposure to different stimuli (MP, 2% KCl, and MP & 2% KCl). The records of brain spontaneous EEG activity, slow potential changes (SPC), and spindle shaped firings were obtained through an interfaced computer. The results showed increases in the amplitude of evoked spindles by about 87%, 17%, and 226% for MP, 2% KCl, and MP & 2% KCl; respectively, as compared to values for the control group. These results showed that the evoked spindle is a more sensitive indicator of the effect of exposure to EMFs from MP. PMID:23675079

  8. 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.

  9. Anatomical compression due to high volume convection-enhanced delivery to the brain

    PubMed Central

    Valles, Francisco; Fiandaca, Massimo S.; Bringas, John; Dickinson, Peter; LeCouteur, Richard; Higgins, Robert; Berger, Mitchel; Forsayeth, John; Bankiewicz, Krystof S.

    2009-01-01

    Objective Our group has pioneered the use of gadolinium liposomes (GDL) in convection-enhanced delivery (CED) using real-time MRI (magnetic resonance imaging) to visualize the distribution of therapeutics in in non-human primate (NHP) and canine brain. We have shown that this procedure is highly predictable and safe. In the course of recent studies, however, we noted that infusion of large volumes caused local anatomical alterations, such as ventricular compression, to occur. This study reports our analysis of CED infusions into normal brains and those compromised by tumors and how monitoring the CED infusion with MRI may be helpful in preventing some complications. Methods A total of fifty-four CED infusions using gadolinium liposomes (GDL) were performed in seven canines and ten NHPs, and monitored using real-time MRI. The canines, harboring brain tumors, received infusions of GDL as well as a chemotherapeutic agent via CED. The NHPs were normal and received GDL infusions alone. Real-time analysis of the CED infusion was carried looking for proper catheter position, and infusion reflux, leakage, and mass effect. Retrospective analysis allowed assessment of CED volume of distribution versus volume of infusion. Results Approximately ten percent of these infusions caused anatomical compression of the ventricles, especially in the canines with tumors. Reflux along the cannula and leakage of infusate into the ventricular CSF or subarachnoid space was seen. Animal behavior, however, did not appear to be affected acutely or during the time course of the study, and no ventricular compression was noted two weeks after the CED infusion on further brain imaging studies. Conclusion These findings illustrate the value of being able to monitor infusions with real time MRI in order to identify phenomena such as reflux along the cannula, leakage of infusate, and ventricular compression. Especially in tumor patients, the latter could be associated with morbidity. PMID:19687704

  10. Nonlinear changes in brain electrical activity due to cell phone radiation.

    PubMed

    Marino, Andrew A; Nilsen, Erik; Frilot, Clifton

    2003-07-01

    We studied the effect of an electromagnetic field from a cellular telephone on brain electrical activity, using a novel analytical method based on a nonlinear model. The electroencephalogram (EEG) from rabbits was embedded in phase space and local recurrence plots were calculated and quantified using recurrence quantitation analysis to permit statistical comparisons between filtered segments of exposed and control epochs from individual rabbits. When the rabbits were exposed to the radiation from a standard cellular telephone (800 MHz band, 600 mW maximum radiated power) under conditions that simulated normal human use, the EEG was significantly affected in nine of ten animals studied. The effect occurred beginning about 100 ms after initiation of application of the field and lasted approximately 300 ms. In each case, the fields increased the randomness in the EEG. A control procedure ruled out the possibility that the observations were a product of the method of analysis. No differences were found between exposed and control epochs in any animal when the experiment was repeated after the rabbits had been sacrificed, indicating that absorption of radiation by the EEG electrodes could not account for the observed effect. No effect was seen when deposition of energy in the brain was minimized by repositioning the radiating antenna from the head to the chest, showing that the type of tissue that absorbed the energy determined the observed changes in the EEG. We conclude that, in normal use, the fields from a standard cellular telephone can alter brain function as a consequence of absorption of energy by the brain.

  11. Role of MicroRNAs in innate neuroprotection mechanisms due to preconditioning of the brain

    PubMed Central

    Jimenez-Mateos, Eva M.

    2015-01-01

    Insults to the brain that are sub-threshold for damage activate endogenous protective pathways, which can temporarily protect the brain against a subsequent harmful episode. This mechanism has been named as tolerance and its protective effects have been shown in experimental models of ischemia and epilepsy. The preconditioning-stimulus can be a short period of ischemia or mild seizures induced by low doses of convulsant drugs. Gene-array profiling has shown that both ischemic and epileptic tolerance feature large-scale gene down-regulation but the mechanism are unknown. MicroRNAs are a class of small non-coding RNAs of ~20–22 nucleotides length which regulate gene expression at a post-transcriptional level via mRNA degradation or inhibition of protein translation. MicroRNAs have been shown to be regulated after non-harmful and harmful stimuli in the brain and to contribute to neuroprotective mechanisms. This review focuses on the role of microRNAs in the development of tolerance following ischemic or epileptic preconditioning. PMID:25954143

  12. Congenital osteolytic dural fibrosarcoma presenting as a scalp swelling.

    PubMed

    Brohi, Shams Raza; Dilber, Muzamil

    2012-08-01

    An extremely rare case of congenital dural fibrosarcoma is reported in a 2 months old child who presented with scalp swelling since birth. CT scan revealed an osteolytic lesion compressing the underlying atrophic brain. Tumour was completely excised and duroplasty was done with a patch graft. Postoperative CSF leak was managed with aspirations and lumbar puncture.

  13. 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.

  14. Non-isothermal extrudate swell

    NASA Astrophysics Data System (ADS)

    Konaganti, Vinod Kumar; Derakhshandeh, Maziar; Ebrahimi, Marzieh; Mitsoulis, Evan; Hatzikiriakos, Savvas G.

    2016-12-01

    The non-isothermal extrudate swell of a high molecular weight high-density polyethylene (HDPE) in long capillary and slit dies is studied numerically (ANSYS POLYFLOW®) using an integral K-BKZ constitutive model including crystallization kinetics, determined experimentally. The Nakamura model is used for crystallization of the HDPE, where the crystallization rate parameter is evaluated by using the well-known Ziabicki equation. This non-isothermal extrudate swell phenomenon is simulated using the pseudo-time integral K-BKZ model with the Wagner damping function along with the differential form of the Nakamura model to account for the crystallization of the extrudate. The swell measurements were carried out under non-isothermal conditions by extruding the polymer melt at 200 °C through long capillary and slit dies to ambient air at 25 °C, 110 °C, and 200 °C. The numerical results are found to be in excellent agreement with experimental observations.

  15. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ischemi...

  17. Osmotic swelling characteristics of glial cells in the murine hippocampus, cerebellum, and retina in situ.

    PubMed

    Hirrlinger, Petra G; Wurm, Antje; Hirrlinger, Johannes; Bringmann, Andreas; Reichenbach, Andreas

    2008-05-01

    Glial cells are proposed to play a major role in the ionic and osmotic homeostasis in the CNS. Swelling of glial cells contributes to the development of edema in neural tissue under pathological conditions such as trauma and ischemia. In this study, we compared the osmotic swelling characteristics of murine hippocampal astrocytes, cerebellar Bergmann glial cells, and retinal Müller glial cells in acutely isolated tissue slices in response to hypoosmotic stress and pharmacological blockade of Kir channels. Hypoosmotic challenge induced an immediate swelling of somata in the majority of Bergmann glial cells and hippocampal astrocytes investigated, whereas Müller cell bodies displayed a substantial delay in the onset of swelling and hippocampal astroglial processes remained unaffected. Blockade of Kir channels under isoosmotic conditions had no swelling-inducing effect in Müller cell somata but caused a swelling in brain astrocytic somata and processes. Blockade of Kir channels under hypoosmotic conditions induced an immediate and strong swelling in Müller cell somata, but had no cumulative effect to brain astroglial somata. No regulatory volume decrease could be observed in all cell types. The data suggest that Kir channels are differently implicated in cell volume homeostasis of retinal Müller cells and brain astrocytes and that Müller cells and brain astrocytes differ in their osmotic swelling properties.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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...

  4. Swelling

    MedlinePlus

    ... the following: Acute glomerulonephritis Burns , including sunburn Chronic kidney disease Heart failure Liver failure from cirrhosis Nephrotic syndrome Poor nutrition Pregnancy Thyroid disease Too little albumin in the blood ( ...

  5. Precipitants of hepatic encephalopathy induce rapid astrocyte swelling in an oxidative stress dependent manner.

    PubMed

    Lachmann, Vera; Görg, Boris; Bidmon, Hans Jürgen; Keitel, Verena; Häussinger, Dieter

    2013-08-15

    Hepatic encephalopathy (HE) is seen as the clinical manifestation of a low grade cerebral edema with formation of reactive oxygen and nitrogen species (RNOS). Astrocyte swelling is a crucial event and in cultured astrocytes HE-relevant factors almost instantaneously induce the formation of RNOS. However, short term effects of ammonia, inflammatory cytokines and RNOS on the volume of astrocytes and other brain cells as well as the underlying mechanisms are largely unknown, although a pathogenic link between RNOS formation and swelling in HE has been proposed. This issue was addressed in the present study by means of live-cell volume microscopy of brain cells in vitro. Ammonia, diazepam and pro-inflammatory cytokines such as tumor-necrosis factor-α (TNF-α), interferon-γ, interleukin-1β induced within 20min astrocyte swelling by about 25% accompanied by nuclear swelling of similar magnitude. Astrocyte swelling in response to NH4Cl, TNF-α or diazepam was abolished by the antioxidant epigallocatechin-gallate pointing to an involvement of RNOS. NH4Cl-induced astrocyte swelling was sensitive to inhibition of glutamine synthetase, NADPH oxidase or nitric oxide synthases. In line with a NMDA receptor-, prostanoid- and Ca(2+)-dependence of NH4Cl-induced RNOS formation, Ca(2+) chelation and inhibition of NMDA receptors or cyclooxygenase suppressed NH4Cl-induced astrocyte swelling, whereas the Ca(2+)-ionophore ionomycin, NMDA, glutamate and prostanoids induced rapid astrocyte swelling. NH4Cl also induced swelling of cultured microglia in a glutamine-synthesis dependent way, but had no effect on cell volume of cultured neurons. It is concluded that the pathways which trigger RNOS formation in astrocytes also trigger astrocyte swelling, whereas conversely and as shown previously hypoosmotic astrocyte swelling can induce RNOS formation. This establishes a complex interplay with an auto-amplificatory loop between RNOS formation and astrocyte swelling as an important event in

  6. Swelling-resistant nuclear fuel

    DOEpatents

    Arsenlis, Athanasios [Hayward, CA; Satcher, Jr., Joe; Kucheyev, Sergei O [Oakland, CA

    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. Indolent palatal swelling: Catch 22

    PubMed Central

    Sharma, Preeti; Wadhwan, Vijay; Kumar, K. V. Arun; Venkatesh, Arvind; Thapa, Timsy

    2016-01-01

    We present an interesting but intriguing case of an indolent palatal swelling. The lesion was asymptomatic causing little discomfort to the patient and thus was an incidental clinical finding. Provisional diagnosis was a benign, minor salivary gland tumor. Clinical differential diagnoses included benign lymphoepithelial lesion or mucus extravasation phenomenon. Nevertheless, we also considered malignancies such as mucoepidermoid carcinoma, lymphoma, and neoplasm of the maxillary sinus. However, the histopathology revealed a rare clinicopathologic entity prompting immediate treatment of the lesion. PMID:28356700

  8. 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.

  9. Brain-Derived Neurotrophic Factor Serum Levels and Hippocampal Volume in Mild Cognitive Impairment and Dementia due to Alzheimer Disease

    PubMed Central

    Borba, Ericksen Mielle; Duarte, Juliana Avila; Bristot, Giovana; Scotton, Ellen; Camozzato, Ana Luiza; Chaves, Márcia Lorena Fagundes

    2016-01-01

    Background/Aims Hippocampal atrophy is a recognized biomarker of Alzheimer disease (AD) pathology. Serum brain-derived neurotrophic factor (BDNF) reduction has been associated with neurodegeneration. We aimed to evaluate BDNF serum levels and hippocampal volume in clinical AD (dementia and mild cognitive impairment [MCI]). Methods Participants were 10 patients with MCI and 13 with dementia due to AD as well as 10 healthy controls. BDNF serum levels were determined by ELISA and volumetric measures with NeuroQuant®. Results MCI and dementia patients presented lower BDNF serum levels than healthy participants; dementia patients presented a smaller hippocampal volume than MCI patients and healthy participants. Discussion The findings support that the decrease in BDNF might start before the establishment of neuronal injury expressed by the hippocampal reduction. PMID:28101102

  10. The Economic Burden of Traumatic Brain Injury Due to Fatal Traffic Accidents in Shahid Rajaei Trauma Hospital, Shiraz, Iran

    PubMed Central

    Kavosi, Zahra; Jafari, Abdosaleh; Hatam, Nahid; Enaami, Meysam

    2015-01-01

    Background: Traumatic Brain Injuries (TBIs) as a result of traffic accidents are one of the major causes of deaths, which lead to the loss of individuals’ productive and working years of life. Objectives: This study aimed to calculate the economic burden of traumatic brain injuries in fatal crashes at Shahid Rajaei Trauma Hospital, Shiraz, Iran for a period of five years. Patients and Methods: In this descriptive, cross-sectional study the population included people who had died as a result of TBIs during 2009 to 2013 in Shiraz Shahid Rajaei Trauma Hospital. Cost and demographic data were obtained from the participants’ medical records using data gathering forms, and some other information was also collected via telephone calls to the victims’ families. Economic burden of TBIs due to traffic accidents, which led to death, was estimated using the human capital as direct costs of treatment, and the number of potential years of life lost and lost productivity as indirect costs. Results: Deaths resulting from TBIs due to traffic accidents in Shiraz imposed 6.2 billion Rials (511000 USD) of hospital costs, 6390 potential years of life lost, and 506 billion Rials (20 million USD) of productivity lost. In the present study, the mean age of the individuals who died was 38.4 ± 19.41 and the productivity lost per capita was 1.8 billion Rials (73000 USD). Conclusions: The findings of this study indicated that the economic burden of TBIs was high in fatal accidents in Fars Province so that it was equivalent to 0.00011% of Iran’s Gross Domestic Product (GDP) in 2013. Therefore, more attention has to be paid to the rules to prevent the fatal accidents. PMID:25834791

  11. 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

  12. 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.

  13. Swelling-induced surface instabilities in growing poroelastic polymer networks

    NASA Astrophysics Data System (ADS)

    Hennessy, Matthew G.; Vitale, Alessandra; Cabral, Joao T.; Matar, Omar K.

    2016-11-01

    The swelling that occurs when a deformable polymer network absorbs solvent can generate large compressive stresses which, in turn, can lead to a rich variety of surface instabilities. In this talk, we will discuss recent experiments by our group which suggest that the growth of a polymer network by photopolymerisation and the onset of swelling-induced surface instabilities can simultaneously occur and drive the self-assembly of complex three-dimensional structures. In addition, we will present a theoretical model of photopolymersation that captures the growth, swelling, and mechanical response of the polymer network. The model is based on an Eulerian formulation of nonlinear poroelasticity. The transport of monomer is described by a generalisation of Darcy's law that accounts for flow due to gradients in the pressure and composition. A combination of asymptotic analysis and finite-element simulations is used to explore the coupling between growth and instability as well as the resulting surface morphologies.

  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. Neck swelling with renal stone.

    PubMed

    Khan, M K; Taous, A; Sultana, S Z; Sharif, A; Hossain, M M; Mostafa, G; Hussain, M A; Azim, M A; Siddique, M A

    2010-10-01

    Since the advent of screening of calcium and imaging techniques (CT and MRI), hyperparathyroidism has been detected with increasing frequency. Although in the past, most patients present with severe bone and renal diseases, a large number of patients are asymptomatic. Number of parathyroid glands and their ectopic locations in individuals are the problem of its management. Parathyroid adenoma or hyperplasia may be a part of Multiple Endocrine neoplasia type II. This is the story of a boy of 18 years who had got admitted in the department of Otolaryngology, Mymensingh Medical College Hospital with the complaints of a neck swelling, abdominal discomfort, inability to walk, frequency of micturation for almost same duration of 1 year. After search, hypercalcaemia, bilateral renal stone, raised parathormone level and enlarged one parathyroid gland in lower pole of left thyroid lobe was identified. Clinically it was diagnosed as parathyroid adenoma which was proved histologically after surgical excision. Many controversies still exist regarding the treatment policy of parathyroid adenoma.

  16. Obstructive hydrocephalus due to CNS toxocariasis.

    PubMed

    Choi, Jae-Hwan; Cho, Jae-Wook; Lee, Jae-Hyeok; Lee, Sang Weon; Kim, Hak-Jin; Choi, Kwang-Dong

    2013-06-15

    A 46-year-old man developed intermittent headache, diplopia, and visual obscuration for two months. Funduscopic examination showed optic disk swelling in both eyes. Brain MRI exhibited hydrocephalus and leptomeningeal enhancement at the prepontine cistern, left cerebellopontine angle cistern and bilateral cerebral hemisphere, and hemosiderin deposition along the cerebellar folia. CSF analysis revealed an elevated opening pressure with xanthochromic appearance and small amount of red blood cells. Antibody titer against Toxocariasis using ELISA was elevated both in blood and CSF. Obstructive hydrocephalus and hemosiderin deposition in this case may result from the active inflammatory process due to CNS toxocariasis within the subarachnoid space.

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

    PubMed

    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.

  18. 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

  19. Endocrine response to acute changes of brain blood flow due to lower body negative pressure in man.

    PubMed

    Tigranian, R A; Jarullin, K; Kalita, N; Simonov, L; Vigas, M

    1985-06-01

    The decrease of brain flow due to lower body negative pressure (LBNP) was used to study the role of cerebral glucopenia in the activation of anterior pituitary function in 10 young healthy men. During LBNP with a maximum negative pressure of--50 mm Hg the changes in heart rate, blood pressure cerebral blood flow (with the aid of rheoencephalography) and electrocardiogram were recorded and the levels of hGH, ACTH, hPRL, insulin and cortisol were measured with the aid of radioimmunoassay. During the first investigation an infusion of 20% glucose (1 g per min for first 30 min and 0.5 g per min for next 30 min) was used, while during the second investigation (one week later) the infusion of saline was applied. It was found that the infusion of glucose prevented the increase of hGH which was observed only during the infusion of saline. No differences in the level of ACTH, cortisol and hPRL were observed between the investigations with glucose and saline infusion. The increased level of insulin was related to the level of glucose during the infusion, while no changes were found during saline infusion. It was suggested that the increase of hGH level during LBNP resulted from glucopenia in cerebral tissue.

  20. Somato-axodendritic release of oxytocin into the brain due to calcium amplification is essential for social memory.

    PubMed

    Higashida, Haruhiro

    2016-07-01

    Oxytocin (OT) is released into the brain from the cell soma, axons, and dendrites of neurosecretory cells in the hypothalamus. Locally released OT can activate OT receptors, form inositol-1,4,5-trisphosphate and elevate intracellular free calcium (Ca(2+)) concentrations [(Ca(2+)) i ] in self and neighboring neurons in the hypothalamus, resulting in further OT release: i.e., autocrine or paracrine systems of OT-induced OT release. CD38-dependent cyclic ADP-ribose (cADPR) is also involved in this autoregulation by elevating [Ca(2+)] i via Ca(2+) mobilization through ryanodine receptors on intracellular Ca(2+) pools that are sensitive to both Ca(2+) and cADPR. In addition, it has recently been reported that heat stimulation and hyperthermia enhance [Ca(2+)] i increases by Ca(2+) influx, probably through TRPM2 cation channels, suggesting that cADPR and TRPM2 molecules act as Ca(2+) signal amplifiers. Thus, OT release is not simply due to depolarization-secretion coupling. Both of these molecules play critical roles not only during labor and milk ejection in reproductive females, but also during social behavior in daily life in both genders. This was clearly demonstrated in CD38 knockout mice in that social behavior was impaired by reduction of [Ca(2+)] i elevation and subsequent OT secretion. Evidence for the associations of CD38 with social behavior and psychiatric disorder is discussed, especially in subjects with autism spectrum disorder.

  1. Eosinophilic Granuloma Presenting as Palatal Swelling

    PubMed Central

    Babu, B. Balaji; Nadendla, Lakshmi Kavitha; Madki, Pooja

    2016-01-01

    Swellings involving palate can be challenging to diagnose for the clinician as they have wide range of origin which can result from developmental, inflammatory, reactive or a neoplastic process. The clinical presentation of these swellings is similar and difficult to differentiate from each other. So it is important to take proper history from the patient and subject the patient to appropriate laboratory and radiographic investigations and finally biopsy is mandatory for accurate diagnosis. Thus, this article highlights on various common palatal swellings, their clinical presentation, and differential diagnosis helpful for proper diagnosis of swellings associated with palate. PMID:27891486

  2. 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.

  3. In vivo magnetic resonance imaging investigating the development of experimental brain metastases due to triple negative breast cancer.

    PubMed

    Hamilton, Amanda M; Foster, Paula J

    2017-02-01

    Triple negative breast cancer (TNBC), when associated with poor outcome, is aggressive in nature with a high incidence of brain metastasis and the shortest median overall patient survival after brain metastasis development compared to all other breast cancer subtypes. As therapies that control primary cancer and extracranial metastatic sites improve, the incidence of brain metastases is increasing and the management of patients with breast cancer brain metastases continues to be a significant clinical challenge. Mouse models have been developed to permit in depth evaluation of breast cancer metastasis to the brain. In this study, we compare the efficiency and metastatic potential of two experimental mouse models of TNBC. Longitudinal MRI analysis and end point histology were used to quantify initial cell arrest as well as the number and volume of metastases that developed in mouse brain over time. We showed significant differences in MRI appearance, tumor progression and model efficiency between the syngeneic 4T1-BR5 model and the xenogeneic 231-BR model. Since TNBC does not respond to many standard breast cancer treatments and TNBC brain metastases lack effective targeted therapies, these preclinical TNBC models represent invaluable tools for the assessment of novel systemic therapeutic approaches. Further pursuits of therapeutics designed to bypass the blood tumor barrier and permit access to the brain parenchyma and metastatic cells within the brain will be paramount in the fight to control and treat lethal metastatic cancer.

  4. Stress response of bovine artery and rat brain tissue due to combined translational shear and fixed unconfined compression

    NASA Astrophysics Data System (ADS)

    Leahy, Lauren

    During trauma resulting from impacts and blast waves, sinusoidal waves permeate the brain and cranial arterial tissue, both non-homogeneous biological tissues with high fluid contents. The experimental shear stress response to sinusoidal translational shear deformation at 1 Hz and 25% strain amplitude and either 0% or 33% compression is compared for rat brain tissue and bovine aortic tissue. Both tissues exhibit Mullins effect in shear. Harmonic wavelet decomposition, a novel application to the mechanical response of these tissues, shows significant 1 Hz and 3 Hz components. The 3 Hz component magnitude in brain tissue, which is much larger than in aortic tissue, may correlate to interstitial fluid induced drag forces that decrease on subsequent cycles perhaps because of damage resulting in easier fluid movement. The fluid may cause the quasiperiodic, viscoelastic behavior of brain tissue. The mechanical response differences under impact may cause shear damage between arterial and brain connections.

  5. Hygro-thermal mechanical behavior of Nafion during constrained swelling

    NASA Astrophysics Data System (ADS)

    Silberstein, Meredith N.; Boyce, Mary C.

    Durability is a major limitation of current proton exchange membrane fuel cells. Mechanical stress due to hygro-thermal cycling is one failure mechanism of the polymer electrolyte membrane. In previous work the cyclic rate, temperature, and hydration dependent elastic-viscoplastic mechanical behavior of Nafion has been extensively investigated in uniaxial and biaxial tension, serving as a data basis and means of validation for a three-dimensional constitutive model. Here, the important effect of loading via constrained swelling is studied. Specifically, two types of loading are investigated: partially constrained swelling via a bimaterial swelling test and hygro-thermal cycling within a fuel cell. The bimaterial swelling conditions are examined via experiments in conjunction with modeling. Nafion/GDL bimaterial strips were hydrated and observed to curl significantly with the membrane on the convex side due to the large Nafion hygro-expansion coefficient. Upon drying the bimaterial strips developed a slight reverse curvature with the membrane on the concave side due to the plastic deformation which had occurred in the membrane during hydration. Finite element simulations utilizing the Nafion constitutive model successfully predicted the behavior during hydration and drying, providing insight on the constrained swelling physics and the ability of the model to predict such events. Simulations of in situ fuel cell hygro-thermal cycling are performed via a simplified two-dimensional fuel cell model. The simulation results confirm the finding of other studies that a tensile stress develops in the membrane during drying. Further, a concentration of negative hydrostatic pressure is found to develop just inside the channel region in the dried state supporting the theory of hygro-thermal driven mechanical stresses causing pinhole formation in the channel. The amplitude of the pressure cycling is found to be large and sensitive to both hygro-thermal ramp time and hold time

  6. Hand Swelling during Exercise: A Concern?

    MedlinePlus

    Diseases and Conditions Edema What causes hand swelling during exercise? I walk several times a week, and my fingers get puffy to the ... Original article: http://www.mayoclinic.org/diseases-conditions/edema/expert-answers/hand-swelling/FAQ-20058255 . Mayo Clinic ...

  7. Bilateral parotid swelling: a radiological review

    PubMed Central

    Gadodia, A; Bhalla, A S; Sharma, R; Thakar, A; Parshad, R

    2011-01-01

    Bilateral parotid swelling is not an uncommon occurrence and may pose a challenge for clinicians and radiologists. Numerous causes of bilateral parotid swellings have been identified. The purpose of this pictorial review is to display this wide array with a focus on multimodality approach. PMID:21960397

  8. 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

  9. Brain energy metabolism spurns fatty acids as fuel due to their inherent mitotoxicity and potential capacity to unleash neurodegeneration.

    PubMed

    Schönfeld, Peter; Reiser, Georg

    2017-03-30

    The brain uses long-chain fatty acids (LCFAs) to a negligible extent as fuel for the mitochondrial energy generation, in contrast to other tissues that also demand high energy. Besides this generally accepted view, some studies using cultured neural cells or whole brain indicate a moderately active mitochondrial β-oxidation. Here, we corroborate the conclusion that brain mitochondria are unable to oxidize fatty acids. In contrast, the combustion of liver-derived ketone bodies by neural cells is long-known. Furthermore, new insights indicate the use of odd-numbered medium-chain fatty acids as valuable source for maintaining the level of intermediates of the citric acid cycle in brain mitochondria. Non-esterified LCFAs or their activated forms exert a large variety of harmful side-effects on mitochondria, such as enhancing the mitochondrial ROS generation in distinct steps of the β-oxidation and therefore potentially increasing oxidative stress. Hence, the question arises: Why do in brain energy metabolism mitochondria selectively spurn LCFAs as energy source? The most likely answer are the relatively higher content of peroxidation-sensitive polyunsaturated fatty acids and, the low antioxidative defense in brain tissue. There are two remarkable peroxisomal defects, one relating to α-oxidation of phytanic acid and the other to uptake of very long-chain fatty acids (VLCFAs) which lead to pathologically high tissue levels of such fatty acids. Both, the accumulation of phytanic acid and that of VLCFAs give an enlightening insight into harmful activities of fatty acids on neural cells, which possibly explain why evolution has prevented brain mitochondria from the equipment of with significant β-oxidation enzymatic capacity.

  10. Unexpected death in persons with symptomatic epilepsy due to glial brain tumors: a report of two cases and review of the literature.

    PubMed

    Büttner, A; Gall, C; Mall, G; Weis, S

    1999-03-15

    Two cases of unexpected death in persons with epileptic seizures due to a brain tumor are presented which encompassed an astrocytoma WHO grade II and an anaplastic astrocytoma WHO grade III. A 35-year-old man was found somnolent and disoriented at home. A computed tomography (CT) scan revealed a tumor of the right frontal lobe suggestive for an oligodendroglioma. During an angiographic examination the patient experienced an epileptic seizure. Some weeks later, the man was found dead in front of his house with a fresh bite mark of the tongue. Neuropathological examination revealed an astrocytoma WHO grade II of the right frontal lobe. A 47-year-old man plunged into a swimming-pool and was found submerged some minutes later. After resuscitation he survived comatose for 8 days but finally died due to severe hypoxic brain damage. He had been operated on a brain tumor of the temporal lobe 1 year before the accident. Neuropathological examination revealed residual tumor tissue at the operation site corresponding to an anaplastic astrocytoma WHO grade III. Although rare, death in persons with epileptic seizures due to brain tumors is an important mechanism of death encountered by the forensic pathologist.

  11. Effect of swelling pressure on local volume change in unsaturated sand-bentonite buffer material

    SciTech Connect

    Shooshpasha, I.; Mohamed, A.M.O.; Yong, R.N.; Onofrei, C.

    1996-08-01

    This study was designed to investigate the effect of swelling pressure on local volume changes in unsaturated sand-bentonite based buffer material used in a nuclear fuel waste disposal vault. A laboratory mixture of sodium bentonite and graded silica sand in equal proportion by dry weight was used in both ambient and elevated temperatures experiments. At high water content locations within the tested specimens, the density was reduced by 3.57% from its initial values due to swelling. The swelling pressure as a function of distance was calculated by 4 different models. The calculated results have indicated that the density distribution within the specimen is affected by swelling potential distribution. The calculated swelling pressure values vary as a function of water content, reaching 1 MPa at the source of water intake, i.e., at high water content zone, and 2 MPa at the heater side, i.e., at low water content zone.

  12. Influence of the lateral ventricles and irregular skull base on brain kinematics due to sagittal plane head rotation.

    PubMed

    Ivarsson, J; Viano, D C; Lövsund, P

    2002-08-01

    Two-dimensional physical models of the human head were used to investigate how the lateral ventricles and irregular skull base influence kinematics in the medial brain during sagittal angular head dynamics. Silicone gel simulated the brain and was separatedfrom the surrounding skull vessel by paraffin that provided a slip interface between the gel and vessel. A humanlike skull base model (HSB) included a surrogate skull base mimicking the irregular geometry of the human. An HSBV model added an elliptical inclusion filled with liquid paraffin simulating the lateral ventricles to the HSB model. A simplified skull base model (SSBV) included ventricle substitute but approximated the anterior and middle cranial fossae by a flat and slightly angled surface. The models were exposed to 7600 rad/s2 peak angular acceleration with 6 ms pulse duration and 5 deg forced rotation. After 90 deg free rotation, the models were decelerated during 30 ms. Rigid body displacement, shear strain and principal strains were determined from high-speed video recorded trajectories of grid markers in the surrogate brains. Peak values of inferior brain surface displacement and strains were up to 10.9X (times) and 3.3X higher in SSBV than in HSBV. Peak strain was up to 2.7X higher in HSB than in HSBV. The results indicate that the irregular skull base protects nerves and vessels passing through the cranial floor by reducing brain displacement and that the intraventricular cerebrospinal fluid relieves strain in regions inferior and superior to the ventricles. The ventricles and irregular skull base are necessary in modeling head impact and understanding brain injury mechanisms.

  13. The excessively small ventricle on computed axial tomography of the brain.

    PubMed

    Hahn, F J; Schapiro, R L

    1976-01-01

    Computed axial tomography has made it possible to observe excessively small ventricles in a variety of disorders of the CNS. This finding is presumably due to non-specific and diffuse swelling of brain parenchyma, and is illustrated in cases of trauma, neoplasm, encephalitis, pseudotumor cerebri, metabolic disorder, and probable dilantin effect. It is likely that other causes will be encountered in the future.

  14. Inhibitors of the mitochondrial permeability transition reduce ammonia-induced cell swelling in cultured astrocytes.

    PubMed

    Reddy, Pichili V B; Rama Rao, Kakulavarapu V; Norenberg, Michael D

    2009-09-01

    Ammonia is the principal neurotoxin implicated in the pathogenesis of hepatic encephalopathy, and astrocytes are the neural cells predominantly affected in this condition. Astrocyte swelling (cytotoxic edema) represents a critical component of the brain edema in acute form of hepatic encephalopathy (acute liver failure, ALF). Although mechanisms of astrocyte swelling by ammonia are not completely understood, cultured astrocytes exposed to pathophysiological levels of ammonia develop the mitochondrial permeability transition (mPT), a process that was shown to result in astrocyte swelling. Cyclosporin A (CsA), a traditional inhibitor of the mPT, was previously shown to completely block ammonia-induced astrocyte swelling in culture. However, the efficacy of CsA to protect cytotoxic brain edema in ALF is problematic because it poorly crosses the blood-brain barrier, which is relatively intact in ALF. We therefore examined the effect of agents that block the mPT but are also known to cross the blood-brain barrier, including pyruvate, magnesium, minocycline, and trifluoperazine on the ammonia-induced mPT, as well as cell swelling. Cultured astrocytes exposed to ammonia for 24 hr displayed the mPT as demonstrated by a CsA-sensitive dissipation of the mitochondrial inner membrane potential. Pyruvate, minocycline, magnesium, and trifluoperazine significantly blocked the ammonia-induced mPT. Ammonia resulted in a significant increase in cell volume, which was blocked by the above-mentioned agents to a variable degree. A regression analysis indicated a high correlation between the effectiveness of reducing the mPT and cell swelling. Our data suggest that all these agents have therapeutic potential in mitigating brain edema in ALF.

  15. 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

  16. 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.

  17. Acute care alternate-level-of-care days due to delayed discharge for traumatic and non-traumatic brain injuries.

    PubMed

    Amy, Chen; Zagorski, Brandon; Chan, Vincy; Parsons, Daria; Vander Laan, Rika; Colantonio, Angela

    2012-05-01

    Alternate-level-of-care (ALC) days represent hospital beds that are taken up by patients who would more appropriately be cared for in other settings. ALC days have been found to be costly and may result in worse functional outcomes, reduced motor skills and longer lengths of stay in rehabilitation. This study examines the factors that are associated with acute care ALC days among patients with acquired brain injury (ABI). We used the Discharge Abstract Database to identify patients with ABI using International Classification of Disease-10 codes. From fiscal years 2007/08 to 2009/10, 17.5% of patients with traumatic and 14% of patients with non-traumatic brain injury had at least one ALC day. Significant predictors include having a psychiatric co-morbidity, increasing age and length of stay in acute care. These findings can inform planning for care of people with ABI in a publicly funded healthcare system.

  18. 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

  19. Radiation preparation and swelling behavior of sodium carboxymethyl cellulose hydrogels

    NASA Astrophysics Data System (ADS)

    Liu, Pengfei; Zhai, Maolin; Li, Jiuqiang; Peng, Jing; Wu, Jilan

    2002-03-01

    Sodium carboxymethyl cellulose (CMC) is a kind of degraded polymer under γ-irradiation. However, in this work, it has been found that CMC crosslinks partially to form hydrogel by radiation technique at more than 20% CMC aqueous solution. The gel fraction increases with the dose. The crosslinking reaction of CMC is promoted in the presence of N 2 or N 2O due to the increase of free radicals on CMC backbone, but gel fraction of CMC hydrogel is not high (<40%). Some important values related to this kind of new CMC hydrogel synthesized under different conditions, such as radiation yield of crosslinking G( x), gelation dose Rg, number average molecular weight of network Mc were calculated according to the Charlesby-Pinner equation. The results indicated that although crosslinked CMC hydrogel could be prepared by radiation method, the rate of radiation degradation of CMC was faster than that of radiation crosslinking due to the character of CMC itself. Swelling dynamics of CMC hydrogel and its swelling behavior at different conditions, such as acidic, basic, inorganic salt as well as temperature were also investigated. Strong acidity, strong basicity, small amount of inorganic salts and lower temperature can reduce swelling ratio.

  20. 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

  1. Protective effects of melatonin and vitamin E in brain damage due to gamma radiation: an experimental study.

    PubMed

    Erol, Fatih S; Topsakal, Cahide; Ozveren, M Faik; Kaplan, Metin; Ilhan, Nevin; Ozercan, I Hanifi; Yildiz, Oguz G

    2004-01-01

    Gamma radiation is known to cause serious damage in the brain, and many agents have been used for neuroprotection. In this study, lipid peroxidation levels and histopathological changes in brain tissues of whole-body irradiated rats with likely radiation injury were compared to those with melatonin and vitamin E protection. Forty rats in four equal groups were used. The control group received neither radiation nor medication. The remaining groups received doses of 720 cGy in two equal fractions 12 h apart. The second group received radiation but no medication, the third received radiation plus 100 mg/kg per day of vitamin E i.p., and the fourth received radiation plus 100 mg/kg per day of melatonin i.p. over 5 days. On the 10th postoperative day, all the rats were decapitated and specimens from parietal cortices were analyzed for tissue malondialdehyde (MDA) levels and histopathological changes. Increases in MDA were relatively well prevented by melatonin treatment but less so with vitamin E therapy. On histopathological examination, melatonin significantly reduced the rates of edema, necrosis, and neuronal degeneration, whereas vitamin E reduced only necrosis. Neither substance was capable of preventing vasodilatation. In conclusion, melatonin may be useful in preventing the pathological changes of secondary brain damage as a result of free oxygen radicals generated by irradiation.

  2. Morphing of geometric composites via residual swelling.

    PubMed

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

    2015-08-07

    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.

  3. 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

  4. 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.

  5. Mechanisms affecting swelling in alloys with precipitates

    SciTech Connect

    Mansur, L.K.; Haynes, M.R.; Lee, E.H.

    1980-01-01

    In alloys under irradiation many mechanisms exist that couple phase instability to cavity swelling. These are compounded with the more familiar mechanisms associated with point defect behavior and the evolution of microstructure. The mechanisms may be classified according to three modes of operation. Some affect cavity swelling directly by cavity-precipitate particle association, others operate indirectly by precipitate-induced changes in sinks other than cavities and finally there are mechanisms that are mediated by precipitate-induced changes in the host matrix. The physics of one mechanism of each type is developed in detail and the results compared where possible to experimental measurements. In particular, we develop the theory necessary to treat the effects on swelling of precipitation-induced changes in overall sink density; precipitation-induced changes in point defect trapping by solute depletion and creation of precipitate particle-matrix interfacial trap sites.

  6. Cyclic swelling as a phenomenon inherent to biodegradable polyesters.

    PubMed

    Dittrich, Milan; Snejdrova, Eva

    2014-11-01

    The aim of this study is to evaluate and describe the phenomenon and mechanism of the spontaneous cyclic swelling and deswelling of linear and branched aliphatic polyesters in the aqueous medium. The fluctuation of gel volume in one or several cycles as an inherent property of biodegradable and bioerodible materials has not yet been described. We have observed the process at linear and branched polyesters of aliphatic α-hydroxy acids. The period of duration of cycles was in order of hours to days, as influenced by the size of the bodies ranging from 25 to 1000 mg, the temperature in the range of 7°C-42°C, ionic strength, and pH value. The results demonstrated that swelling is accompanied by hydrolysis of ester bonds with the development of small water-soluble osmotically active molecules. After reaching a higher degree of swelling, the obstruction effect of the gel decreases and the diffusion of soluble degradation products from the body to the environment prevails. A decrease in osmotic pressure inside the body and a decrease in the hydrophilic character of the gel matrix result in deswelling by a collapse of the structure, probably due to hydrophobic interactions of nonpolar polyester chains.

  7. 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.

  8. 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.

  9. 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

  10. PFAPA with facial swelling- a new association?

    PubMed

    Khodaghalian, B; Tewary, K K; Narchi, H

    2013-05-01

    PFAPA (periodic fever, apthous stomatitis, pharyngitis, cervical adenitis) is a rare condition of unknown cause affecting children. Although the exact etiology is unknown, inflammatory, immunological or genetic causes have been suggested. The diagnosis is made by exclusion of other causes of periodic fever. Although management is essentially symptomatic, single corticosteroid dose, tonsillectomy and Cimetidine has been shown to be associated with resolution of symptoms. Although abdominal pain and genital ulcers have been reported in association with PFAPA, unilateral transient facial swelling has not been previously reported. The authors present a hitherto unreported association of PFAPA with recurrent episodes of unilateral facial swelling.

  11. 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.

  12. Dart model for irradiation-induced swelling of dispersion fuel elements including aluminum-fuel interaction

    SciTech Connect

    Rest, J.; Hofman, G.L.

    1997-06-01

    The Dispersion Analysis Research Tool (DART) contains models for fission-gas induced fuel swelling, interaction of fuel with the matrix aluminum, resultant reaction-product swelling, and calculation of the stress gradient within the fuel particle. The effects of an aluminide shell on fuel particle swelling are evaluated. Validation of the model is demonstrated by a comparison of DART calculations of fuel swelling of U{sub 3}SiAl-Al and U{sub 3}Si{sub 2}-Al for various dispersion fuel element designs with the data. DART results are compared with data for fuel swelling Of U{sub 3}SiAl-Al in plate, tube, and rod configurations as a function of fission density. Plate and tube calculations were performed at a constant fuel temperature of 373 K and 518 K, respectively. An irradiation temperature of 518 K results in a calculated aluminide layer thickness for the Russian tube that is in the center of the measured range (16 {mu}m). Rod calculations were performed with a temperature gradient across the rod characterized by surface and central temperatures of 373 K and 423 K, respectively. The effective yield stress of irradiated Al matrix material and the aluminide was determined by comparing the results of DART calculations with postirradiation immersion volume measurement of U{sub 3}SiAl plates. The values for the effective yield stress were used in all subsequent simulations. The lower calculated fuel swelling in the rod-type element is due to an assumed biaxial stress state. Fuel swelling in plates results in plate thickness increase only. Likewise, in tubes, only the wall thickness increases. Irradiation experiments have shown that plate-type dispersion fuel elements can develop blisters or pillows at high U-235 burnup when fuel compounds exhibiting breakaway swelling are used at moderate to high fuel volume fractions. DART-calculated interaction layer thickness and fuel swelling follows the trends of the observations. 3 refs., 2 figs.

  13. Foot Swelling during Air Travel: A Concern?

    MedlinePlus

    Diseases and Conditions Edema What causes leg and foot swelling during air travel? Answers from Sheldon G. Sheps, M.D. Leg and foot ... 191. Sterns RH. Clinical manifestations and diagnosis of edema in adults. http://www.uptodate.com/home. Accessed ...

  14. Bilateral Parotid Swelling in Polycystic Ovarian Syndrome.

    PubMed

    Yakubov, Yakov; Mandel, Louis

    2016-05-01

    Polycystic ovarian syndrome (PCOS) is recognized by the presence of polycystic ovaries, irregular menstruation, and increased androgen levels. Many patients have insulin resistance or impaired glucose tolerance and an associated development of type 2 diabetes mellitus. A patient with PCOS is presented whose cosmetic concerns centered on the prolonged existence of substantial bilateral parotid swelling. The pathophysiology, diagnosis, and therapy of sialosis are discussed.

  15. Structural and functional improvements due to robot-assisted gait training in the stroke-injured brain.

    PubMed

    Yang, Hea Eun; Kyeong, Sunghyon; Lee, Seung Hwa; Lee, Won-Jae; Ha, Sang Won; Kim, Seung Min; Kang, Hyunkoo; Lee, Won Min; Kang, Chang Soon; Kim, Dae Hyun

    2017-01-10

    Robot-assisted gait training (RAGT) can improve walking ability after stroke. Because the underlying mechanisms are still unknown, we analyzed changes in post-stroke injured brains after RAGT. Ten non-ambulatory patients receiving inpatient rehabilitation were examined within 3 months of stroke onset. RAGT consisted of 45min of training, 3days per week. We acquired diffusion tensor imaging (DTI) data before and after 20 sessions of RAGT. Fractional anisotropy (FA) maps were then used to determine neural changes after RAGT. Fugl-Meyer motor assessment of the lower extremity, motricity index of the lower extremity, functional ambulation category, and trunk control tests were also conducted before training, after 10 and 20 RAGT sessions, and at the 1-month follow-up. After RAGT, the supplementary motor area of the unaffected hemisphere showed increased FA, but the internal capsule, substantia nigra, and pedunculopontine nucleus of the affected hemisphere showed decreased FA. All clinical outcome measures improved after 20 sessions of RAGT. Our findings indicate that RAGT can facilitate plasticity in the intact supplementary motor area, but not the injured motor-related areas, in the affected hemisphere.

  16. Postmortem angiography in computed tomography and magnetic resonance imaging in a case of fatal hemorrhage due to an arterio-venous malformation in the brain.

    PubMed

    Franckenberg, Sabine; Schulze, Claudia; Bolliger, Stephan A; Gascho, Dominic; Thali, Michael J; Flach, Patricia M

    2015-05-01

    Autopsy is the traditional gold standard for determining the cause and manner of death in a forensic death investigation. However, postmortem imaging plays an ever-growing role in preliminary examination, even replacing conventional autopsy in some cases. This case report presents a case of massive intra-axial brain hemorrhage due to an arterio-venous malformation. The cause and manner of death were exclusively determined by postmortem radiology. Based on radiological findings, the autopsy was considered redundant and cancelled by the public prosecutor.

  17. Brain damage in dogs immediately following pulsatile and non-pulsatile blood flows in extracorporeal circulation

    PubMed Central

    Sanderson, J. M.; Wright, G.; Sims, F. W.

    1972-01-01

    The brains of dogs subjected to total cardiac bypass were examined for early signs of ischaemic nerve cell changes. Diffuse nerve cell changes were found immediately following two- and three-hour non-pulsatile perfusions but not following pulsatile perfusions of the same durations. The nerve cell changes found in the brains were acute cell swelling and early ischaemic cell change. Acute cell swelling was found only in the cerebellar Purkinje cells. Ischaemic cell change was found in several regions of the brain but the cerebral cortex and cerebellar Purkinje cells were most frequently affected. Diffuse nerve cell changes are attributed to non-pulsatile blood flow but some complicating factors are recognized. Focal lesions found in three brains may have been due to embolism by blood cell aggregates and/or gas microbubbles. Images PMID:5039442

  18. A fatal presentation of dermatomyositis with facial swelling.

    PubMed

    Dwivedi, Nishant; Michael, Christie; Lew, D Betty; Arnold, Sandra; Igarashi, Masanori; Bertorini, Tulio; Thompson, Jerome W; Myers, Linda K; Brown, Monica L

    2012-05-01

    Juvenile dermatomyositis (JDM) is the most common inflammatory autoimmune myopathy in children. Most common presentations consist of heliotrophic rash and/or gottron's papules in addition to proximal muscle weakness. A typical presentations have been reported. We present a 13-year-old African American male who presented with a two-week history of bilateral periorbital edema that was unresponsive to glucocorticoids. He had elevated transaminases but no detectable muscle weakness. A muscle biopsy was consistent with juvenile dermatomyositis. This case highlights the need to consider dermatomyositis in cases of facial swelling and the use of aggressive immunosuppressive therapies due to its associated vasculopathies.

  19. 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.

  20. Effects of estradiol on ischemic factor-induced astrocyte swelling and AQP4 protein abundance.

    PubMed

    Rutkowsky, Jennifer M; Wallace, Breanna K; Wise, Phyllis M; O'Donnell, Martha E

    2011-07-01

    In the early hours of ischemic stroke, cerebral edema forms as Na, Cl, and water are secreted across the blood-brain barrier (BBB) and astrocytes swell. We have shown previously that ischemic factors, including hypoxia, aglycemia, and arginine vasopressin (AVP), stimulate BBB Na-K-Cl cotransporter (NKCC) and Na/H exchanger (NHE) activities and that inhibiting NKCC and/or NHE by intravenous bumetanide and/or HOE-642 reduces edema and infarct in a rat model of ischemic stroke. Estradiol also reduces edema and infarct in this model and abolishes ischemic factor stimulation of BBB NKCC and NHE. There is evidence that NKCC and NHE also participate in ischemia-induced swelling of astrocytes. However, little is known about estradiol effects on astrocyte cell volume. In this study, we evaluated the effects of AVP (100 nM), hypoxia (7.5% O(2)), aglycemia, hypoxia (2%)/aglycemia [oxygen glucose deprivation (OGD)], and estradiol (1-100 nM) on astrocyte cell volume using 3-O-methyl-d-[(3)H]glucose equilibration methods. We found that AVP, hypoxia, aglycemia, and OGD (30 min to 5 h) each significantly increased astrocyte cell volume, and that estradiol (30-180 min) abolished swelling induced by AVP or hypoxia, but not by aglycemia or OGD. Bumetanide and/or HOE-642 also abolished swelling induced by AVP but not aglycemia. Abundance of aquaporin-4, known to participate in ischemia-induced astrocyte swelling, was significantly reduced following 7-day but not 2- or 3-h estradiol exposures. Our findings suggest that hypoxia, aglycemia, and AVP each contribute to ischemia-induced astrocyte swelling, and that the edema-attenuating effects of estradiol include reduction of hypoxia- and AVP-induced astrocyte swelling and also reduction of aquaporin-4 abundance.

  1. 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

  2. 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.

  3. Capillary rise and swelling in cellulose sponges

    NASA Astrophysics Data System (ADS)

    Ha, Jonghyun; Kim, Jungchul; Kim, Ho-Young

    2015-11-01

    A cellulose sponge, which is a mundane example of a porous hydrophilic structure, can absorb and hold a significant amount of liquid. We present the results of experimental and theoretical investigation of the dynamics of the capillary imbibition of various aqueous solutions in the sponge that swells at the same time. We find that the rate of water rise against the resistance caused by gravitational and viscous effects deviates from Washburn's rule beyond a certain threshold height. We rationalize the novel power law of the rise height versus time by combining Darcy's law with hygroscopic swelling equation and also predict the threshold height. The scaling law constructed through this work agrees well with the experimental results, shedding light on the physics of capillary flow in deforming porous media.

  4. Genital swellings in silvered langurs: what do they indicate?

    PubMed

    Shelmidine, Nichole; Borries, Carola; Koenig, Andreas

    2007-05-01

    The occurrence of genital swellings was examined in adult female silvered langurs (Trachypithecus cristatus). In contrast to the exaggerated swellings found in cercopithecines and apes, genital swellings in silvered langurs are confined to the vulva and the surrounding perineum, but they may nevertheless convey information similar to that of exaggerated swellings (i.e., correlate with the receptive period and fertility). If so, genital swellings would be expected to occur most frequently in cycling females, and sexual behavior and male interest should most frequently involve females with swellings. Swellings during gestation, if they occur at all, should be most pronounced at the beginning. Swelling sizes (in three size categories) in nine adult females were examined throughout different reproductive states (cycling, pregnant, and lactating), and in relation to proceptivity, receptivity, and attractivity. Data were collected from November 2002 through March 2004 (on 500 of the 502 calendar days) at the Wildlife Conservation Society's Bronx Zoo. Female sexual behavior (proceptivity and receptivity) and male inspection (attractivity) were recorded each day for 6 hr by video camera (2,948 hr total) and analyzed as present or absent for each female day. Swellings were assessed directly (not from videotapes). In contrast to the predictions, swellings occurred significantly less frequently in cycling females (compared to pregnant females) and no regular, cyclic pattern could be detected. Some females conceived without a swelling. Female attractivity was independent of swellings but coincided with proceptive behavior. Swellings occurred most frequently in pregnant females, especially toward the end of the gestation period. Therefore, genital swellings in silvered langurs are not similar to exaggerated swellings or the smaller genital swellings that have been described for some other primates. It is currently not clear what they signal to conspecifics. Male behavior needs

  5. 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

  6. 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

  7. Evaluation of ettringite-related swelling mechanisms for treated chromite ore processing residue.

    PubMed

    Moon, Deok Hyun; Wazne, Mahmoud; Dermatas, Dimitris; Sanchez, Adriana M; Cheong, Kyung Hoon; Park, Jeong-Hun

    2015-01-01

    Accelerated one-dimensional unconfined swell tests were conducted for ferrous sulfate chromite ore processing residue (COPR) field-treated samples. The field-treated samples were subjected to wet and dry cycles over 100 days to accelerate the lithification of the samples. Parallel laboratory experiments were performed to investigate the effects of mineralogy on COPR swell under controlled conditions. The field and laboratory samples were treated with ferrous sulfate at a ferrous-to-Cr(6+) molar stoichiometric ratios of eight (8×) and five (5×). X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) analyses were used to investigate the mineralogical changes upon treatment. The swell results indicated that significant COPR swelling was observed in all of the tested samples. The swelling was more pronounced in the 5× treated COPR sample than in the 8× treated COPR sample. Moreover, the laboratory-treated samples showed greater swelling behavior as compared with the field-treated samples, which was most probably due to the high dry density of the COPR, indicating that dry density was a more dominant factor than lithification. XRPD and SEM-EDX results confirmed that significant ettringite formation occurred in all treated samples.

  8. 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.

  9. [Extensive swelling reaction after a pentavalent vaccination].

    PubMed

    Gébus, M; Barbier, C; Bost-Bru, C; Michard-Lenoir, A P; Plantaz, D

    2015-09-01

    Injection site reactions (ISRs) are quite common side effects defined by a local adverse drug reaction directly caused by a vaccine. Twenty-four hours after an intramuscular injection (in the deltoid muscle) of the diphtheria, tetanus, acellular pertussis, inactivated poliomyelitis, Haemophilus influenza type b (DTPCa-Hib) combined vaccine, a 3-year-old boy developed fever. A few hours later, local redness and swelling appeared at the injection site, with rapid extension to the entire limb, it was pain-free, and no other clinical anomalies were present. The patient received intravenous antibiotics for suspected cellulitis. The progression was favorable in 12h (apyrexia and decreased limb swelling), allowing the intravenous antibiotic treatment to be discontinued. Since the child was in excellent general health and recovery was fast, an ISR was diagnosed. Extensive limb swelling is frequent, mostly after the fourth dose of DTPCa-Hib. Deltoid muscle injection of DTP vaccine increases the risk of ISR compared to injection in the thigh, before the age of 3 years. The introduction of acellular pertussis vaccine decreased the risk of general side effects but may increase the risk of ISR. These reactions disappear with symptomatic treatment and do not contraindicate the product.

  10. 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.

  11. Synergistic action of hypoosmolarity and glutamine in inducing acute swelling of retinal glial (Müller) cells.

    PubMed

    Karl, Anett; Wurm, Antje; Pannicke, Thomas; Krügel, Katja; Obara-Michlewska, Marta; Wiedemann, Peter; Reichenbach, Andreas; Albrecht, Jan; Bringmann, Andreas

    2011-02-01

    High blood ammonia, elevated glutamine, and hyponatremia are pathogenic factors contributing to astrocytic swelling and brain edema in liver failure. We investigated the effects of hypoosmolarity, ammonia, and glutamine on the induction of glial cell swelling in freshly isolated slices of the rat retina. Glutamine, but not ammonia or hypoosmolarity per se, evoked a rapid (within one minute) swelling of retinal glial (Müller) cell bodies under hypoosmotic conditions. Under isoosmotic conditions, glutamine evoked a delayed swelling after 10 min of exposure. The effect of glutamine was concentration-dependent, with half-maximal and maximal effects at ∼ 0.1 and 0.5 mM. Glutamine in hypoosmotic solution induced a dissipation of the mitochondrial membrane potential. The effects on the mitochondrial membrane potential and the glial soma size were reduced by (i) agents which inhibit the transfer of glutamine into mitochondria and its hydrolysis there, (ii) inhibition of the mitochondrial permeability transition, (iii) inhibitors of oxidative-nitrosative stress, and (iv) inhibitors of phospholipase A(2) and cyclooxygenase. Glutamine-induced glial swelling was also prevented by ATP and adenosine, acting at adenosine A(1) receptors. The data suggest that hypoosmolarity accelerates the swelling-inducing effect of glutamine on retinal glial cells, and that swelling induction by glutamine is mediated by inducing oxidative-nitrosative stress, inflammatory lipid mediators, and mitochondrial dysfunction.

  12. 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

  13. Modeling multidomain hydraulic properties of shrink-swell soils

    NASA Astrophysics Data System (ADS)

    Stewart, Ryan D.; Abou Najm, Majdi R.; Rupp, David E.; Selker, John S.

    2016-10-01

    Shrink-swell soils crack and become compacted as they dry, changing properties such as bulk density and hydraulic conductivity. Multidomain models divide soil into independent realms that allow soil cracks to be incorporated into classical flow and transport models. Incongruously, most applications of multidomain models assume that the porosity distributions, bulk density, and effective saturated hydraulic conductivity of the soil are constant. This study builds on a recently derived soil shrinkage model to develop a new multidomain, dual-permeability model that can accurately predict variations in soil hydraulic properties due to dynamic changes in crack size and connectivity. The model only requires estimates of soil gravimetric water content and a minimal set of parameters, all of which can be determined using laboratory and/or field measurements. We apply the model to eight clayey soils, and demonstrate its ability to quantify variations in volumetric water content (as can be determined during measurement of a soil water characteristic curve) and transient saturated hydraulic conductivity, Ks (as can be measured using infiltration tests). The proposed model is able to capture observed variations in Ks of one to more than two orders of magnitude. In contrast, other dual-permeability models assume that Ks is constant, resulting in the potential for large error when predicting water movement through shrink-swell soils. Overall, the multidomain model presented here successfully quantifies fluctuations in the hydraulic properties of shrink-swell soil matrices, and are suitable for use in physical flow and transport models based on Darcy's Law, the Richards Equation, and the advection-dispersion equation.

  14. "Spontaneous" CSF Fistula due to Transtegmental Brain Herniation in Combination with Signs of Increased Intracranial Pressure and Petrous Bone Hyperpneumatization: An Illustrative Case Report.

    PubMed

    Rivera, Diones; Fermin-Delgado, Rafael; Stoeter, Peter

    2014-12-01

    Background and Importance Transtegmental brain herniation into the petrous bone is a rare cause of rhinoliquorrhea. Our case presents a combination of several typical clinical and imaging findings illustrating the ongoing etiologic discussion of such cerebrospinal fluid (CSF) fistulas. Clinical Presentation A 53-year-old man presented with nasal discharge after a strong effort to suppress coughing. Imaging revealed a transtegmental herniation of parts of the inferior temporal gyrus into the petrous bone and in addition a combination of signs of chronically increased intracranial pressure and a hyperpneumatization of the petrous bone. The fistula was closed by a middle cranial fossa approach. Conclusion The case illustrates the two main predisposing factors for development of petrous bone CSF fistulas: increased intracranial pressure and thinning of the tegmental roof due to extensive development of air cells. Because the CSF leakage repair does not change the underlying cause, patients have to be informed about the possibility of developing increased intracranial pressure and recurrences of brain herniations at other sites.

  15. “Spontaneous” CSF Fistula due to Transtegmental Brain Herniation in Combination with Signs of Increased Intracranial Pressure and Petrous Bone Hyperpneumatization: An Illustrative Case Report

    PubMed Central

    Rivera, Diones; Fermin-Delgado, Rafael; Stoeter, Peter

    2014-01-01

    Background and Importance Transtegmental brain herniation into the petrous bone is a rare cause of rhinoliquorrhea. Our case presents a combination of several typical clinical and imaging findings illustrating the ongoing etiologic discussion of such cerebrospinal fluid (CSF) fistulas. Clinical Presentation A 53-year-old man presented with nasal discharge after a strong effort to suppress coughing. Imaging revealed a transtegmental herniation of parts of the inferior temporal gyrus into the petrous bone and in addition a combination of signs of chronically increased intracranial pressure and a hyperpneumatization of the petrous bone. The fistula was closed by a middle cranial fossa approach. Conclusion The case illustrates the two main predisposing factors for development of petrous bone CSF fistulas: increased intracranial pressure and thinning of the tegmental roof due to extensive development of air cells. Because the CSF leakage repair does not change the underlying cause, patients have to be informed about the possibility of developing increased intracranial pressure and recurrences of brain herniations at other sites. PMID:25485224

  16. Role of Defects in Swelling and Creep of Irradiated SiC

    SciTech Connect

    Szlufarska, Izabela; Voyles, Paul; Sridharan, Kumar; Katoh, Yutai

    2016-01-16

    Silicon carbide is a promising cladding material because of its high strength and relatively good corrosion resistance. However, SiC is brittle and therefore SiC-based components need to be carefully designed to avoid cracking and failure by fracture. In design of SiC-based composites for nuclear reactor applications it is essential to take into account how mechanical properties are affected by radiation and temperature, or in other words, what strains and stresses develop in this material due to environmental conditions. While thermal strains in SiC can be predicted using classical theories, radiation-induced strains are much less understood. In particular, it is critical to correctly account for radiation swelling and radiation creep, which contribute significantly to dimensional instability of SiC under radiation. Swelling typically increases logarithmically with radiation dose and saturates at relatively low doses (damage levels of a few dpa). Consequently, swelling-induced stresses are likely to develop within a few months of operation of a reactor. Radiation-induced volume swelling in SiC can be as high as 2%, which is significantly higher than the cracking strain of 0.1% in SiC. Swelling-induced strains will lead to enormous stresses and fracture, unless these stresses can be relaxed via some other mechanism. An effective way to achieve stress relaxation is via radiation creep. Although it has been hypothesized that both radiation swelling and radiation creep are driven by formation of defect clusters, existing models for swelling and creep in SiC are limited by the lack of understanding of specific defects that form due to radiation in the range of temperatures relevant to fuel cladding in light water reactors (LWRs) (<1000°C). For example, defects that can be detected with traditional transmission electron microscopy (TEM) techniques account only for 10-45% of the swelling measured in irradiated SiC. Here, we have undertaken an integrated experimental and

  17. Acute fatal parainfectious cerebellar swelling in two children. A rare or an overlooked situation?

    PubMed

    Roulet Perez, E; Maeder, P; Cotting, J; Eskenazy-Cottier, A C; Deonna, T

    1993-12-01

    We report 2 previously healthy children who developed sudden unexpected respiratory arrest and brain death, during a presumed Epstein-Barr meningitis in one case and a multisystemic infection of unknown etiology in the other. Diffuse swelling of the cerebellum with upward transtentorial and downward tonsillar herniation, shown by brain CT-scan and MRI obtained after the acute event, was the most probable cause of death. Review of CT images performed before or at the onset of deterioration already showed discrete signs of early upward herniation of the cerebellar vermis that were initially overlooked. At autopsy in the first case, an acute lymphomonocytic meningoencephalitis with predominant involvement of the cerebellum was observed. Few similar cases were found in the literature, indicating that acute cerebellar swelling is either a very rare or an unrecognized, possibly preventable cause of death in acute inflammatory or non-inflammatory encephalopathies in children.

  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. 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

  20. Anisotropic swelling behavior of the cornea.

    PubMed

    Matsuura, Toyoaki; Ikeda, Hitoe; Idota, Naokazu; Motokawa, Ryuhei; Hara, Yoshiaki; Annaka, Masahiko

    2009-12-24

    The phase equilibrium property and structural and dynamical properties of pig cornea were studied by macroscopic observation of swelling behavior, dynamic light scattering (DLS), and small-angle X-ray scattering (SAXS) under various conditions. It was found that the corneal gel collapses into a compact state isotropically or anisotropically depending on the external conditions. The corneal gel collapses uniformly into a compact state at a temperature above 55 degrees C because of the denaturation of collagen, whereas it collapses along an axis parallel to the optic axis with increasing NaCl concentration. Anisotropic deswelling was also observed during desiccation. SAXS measurements revealed that the periodicity of the collagen fiber of the cornea does not change even at higher NaCl concentration, which indicates that hydration and dehydration resulting from changes in salt concentration simply cause swelling and deswelling of the glycosaminoglycan (GAG), which is located between the regular two-dimensional lattices of collagen fibers, which obliges the change in thickness. From observations of the dynamics of light scattered by the corneal gel, intensity autocorrelation functions that revealed two independent diffusion coefficients were obtained. Divergent behavior in the measured total scattered light intensities and diffusion coefficients with varying temperature was observed. That is, a slowing of the dynamic modes accompanied by increased "static" scattered intensities was observed. This is indicative of the occurrence of a phase transition as a function of temperature.

  1. Counterion-induced swelling of ionic microgels

    NASA Astrophysics Data System (ADS)

    Denton, Alan R.; Tang, Qiyun

    2016-10-01

    Ionic microgel particles, when dispersed in a solvent, swell to equilibrium sizes that are governed by a balance between electrostatic and elastic forces. Tuning of particle size by varying external stimuli, such as pH, salt concentration, and temperature, has relevance for drug delivery, microfluidics, and filtration. To model swelling of ionic microgels, we derive a statistical mechanical theorem, which proves exact within the cell model, for the electrostatic contribution to the osmotic pressure inside a permeable colloidal macroion. Applying the theorem, we demonstrate how the distribution of counterions within an ionic microgel determines the internal osmotic pressure. By combining the electrostatic pressure, which we compute via both Poisson-Boltzmann theory and molecular dynamics simulation, with the elastic pressure, modeled via the Flory-Rehner theory of swollen polymer networks, we show how deswelling of ionic microgels with increasing concentration of particles can result from a redistribution of counterions that reduces electrostatic pressure. A linearized approximation for the electrostatic pressure, which proves remarkably accurate, provides physical insight and greatly eases numerical calculations for practical applications. Comparing with experiments, we explain why soft particles in deionized suspensions deswell upon increasing concentration and why this effect may be suppressed at higher ionic strength. The failure of the uniform ideal-gas approximation to adequately account for counterion-induced deswelling below close packing of microgels is attributed to neglect of spatial variation of the counterion density profile and the electrostatic pressure of incompletely neutralized macroions.

  2. 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

  3. NFκB in the Mechanism of Ammonia-Induced Astrocyte Swelling in Culture

    PubMed Central

    Sinke, A.P.; Jayakumar, A.R.; Panickar, K.S.; Moriyama, M.; Reddy, P.V.B.; Norenberg, M.D.

    2008-01-01

    Astrocyte swelling and brain edema are major neuropathological findings in the acute form of hepatic encephalopathy (fulminant hepatic failure, FHF), and substantial evidence supports the view that elevated brain ammonia level is an important etiological factor in this condition. Although the mechanism by which ammonia brings about astrocyte swelling remains to be determined, oxidative/nitrosative stress and mitogen-activated protein kinases (MAPKs) have been considered as important elements in this process. One factor known to be activated by both oxidative stress and MAPKs is nuclear factor κB (NFκB), a transcription factor that activates many genes, including inducible nitric oxide synthase (iNOS). Since the product of iNOS, nitric oxide (NO), is known to cause astrocyte swelling, we examined the potential involvement of NFκB in ammonia-induced astrocyte swelling. Western blot analysis of cultured astrocytes showed a significant increase in NFκB nuclear translocation (a measure of NFκB activation) from 12 h to 2 days after treatment with NH4Cl (5 mM). Cultures treated with antioxidants, including superoxide dismutase, catalase and vitamin E, as well as the MAPKs inhibitors SB239063 (an inhibitor of p38-MAPK), and SP600125 (an inhibitor of c-Jun N-terminal kinase, JNK) significantly diminished NFκB activation by ammonia, supporting a role of oxidative stress and MAPKs in NFκB activation. The activation of NFκB was associated with increased iNOS protein expression and NO generation, and these changes were blocked by BAY 11-7082, an inhibitor of NFκB. Additionally, ammonia-induced astrocyte swelling was inhibited by the NFκB inhibitors BAY 11-7082 and SN-50, thereby implicating NFκB in the mechanism of astrocyte swelling. Our studies indicate that cultured astrocytes exposed to ammonia display NFκB activation, which is likely a consequence of oxidative stress and activation of MAPKs. NFκB activation appears to contribute to the mechanism of ammonia

  4. Heat-flow anomaly and residual topography in the Mascarene hotspot swell (Indian Ocean)

    NASA Astrophysics Data System (ADS)

    Chiozzi, P.; Verdoya, M.

    2017-03-01

    We review the sea-bottom heat-flow determinations and present a new heat-flow observation on the Mauritius island, which is part of the long-lived Reunion hotspot track. The marine heat flow is on average 66 ± 11 mW m-2 and is consistent with the on-land value of 61 ± 18 mW m-2 found in Mauritius. Since these values do not significantly deviate from the reference cooling-plate model, lithosphere erosion does not seem a likely mechanism for the swell formation. The lack of significant reheating due to a mantle plume impacting the lithosphere base is confirmed by thermal modelling. Moreover, the coherency between on-land and marine data is argument against advective redistribution of heat near the axis of the swell. We also analyse the large-scale features of the ocean lithosphere, which are not simply a function of the plate cooling and can reflect variations in mantle dynamic topography. The predicted topography variation along the swell shows amplitude and wavelength comparable to other hotspots. Both the topographic swell magnitude and the wavelength increase northwards with the increase of the age of volcanism. The estimated flux of material from the mantle follows the same trend, being larger in the northern part of the swell. The result that residual topography and the buoyancy flux are smaller at the active volcano of Reunion could be evidence that the activity of the plume has decreased with time.

  5. Swelling behavior of chitosan hydrogels in ionic liquid-water binary systems.

    PubMed

    Spinks, Geoffrey M; Lee, Chang Kee; Wallace, Gordon G; Kim, Sun I; Kim, Seon Jeong

    2006-10-24

    The swelling behavior of chitosan hydrogels in ionic liquid-water binary systems was studied using hydrophilic room-temperature ionic liquids (RTILs) to elucidate the swelling mechanism of chitosan hydrogels. No penetration of RTIL into a dry chitosan material was observed. Swelling was achieved by soaking in water-RTIL binary mixtures, with larger swelling observed at higher water contents. In one instance, the binary mixture was acidic and produced larger than expected swelling due to the dissociation of the amine groups in the chitosan. The equilibrium binary system content behavior of the chitosan hydrogels depended upon the amount of free water, which is a measure of the number of water molecules that do not interact with the ionic liquid. After evaporation of water, remnant RTIL remained in the chitosan network and hardness testing indicated a plasticization effect, suggesting that the RTIL molecularly mixed with the chitosan. Chitosan hydrogels containing only RTIL were prepared by dropping pure RTIL onto a fully preswollen hydrogel followed by water evaporation. This method may be a useful means for preparing air-stable swollen chitosan gels.

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

    PubMed

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

    2014-06-06

    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.

  7. 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

  8. 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.

  9. The relation between composition and swelling in clays

    USGS Publications Warehouse

    Foster, Margaret D.

    1955-01-01

    The phenomenon of swelling is associated with the hydration of clays; however, all clays do not swell when hydrated. those of the kaolin group, for example, exhibit little or no swelling on hydration. Sodiwm montmoillonite, on the other hand, characteristically swells in water to many times its dry volume. Calcium and magnesium montmorillonite and the hydrous micas, or so called illites, fall between these two extremes in swelling properties, but are, in general, much closer to kaolinite than to sodium montmorillonite in their increase in volume on hydration. These differences in the swelling characteristics of different clays may be related to their chemical composition, to the kind and degree of isomorphous replacements in their structure, and to the amount and nature of their associated exchangeable cations. 

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. 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

  15. 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

  16. Kinetics of dextran crosslinking by epichlorohydrin: a rheometry and equilibrium swelling study.

    PubMed

    Emami Meybodi, Zahraalsadat; Imani, Mohammad; Atai, Mohammad

    2013-02-15

    Curing behavior and gel properties of dextran are investigated during its crosslinking by epichlorohydrin (ECH) using rheometry and equilibrium swelling studies. Each ECH/anhydroglucose unit of different molar ratio (0.16-0.99) was added to a known volume of aqueous dextran solution (25%, w/w) in the presence of sodium hydroxide (1.2-3.6 M) as a catalyst. Gel point was investigated as a function of the reactants concentration. The rheological behavior of the curing gels was evaluated using a rheokinetic model. Swelling behavior of the cured, cylindrical specimens was also studied gravimetrically. Increasing NaOH and ECH concentrations significantly increased the crosslinking reaction rate leading to shorter gel points, which was attributed to more ionization of hydroxyl functional groups of dextran due to higher NaOH concentrations. Degree of swelling vs. the reaction time was decreased sharply as a direct function of increasing NaOH and ECH concentrations up to certain levels, which then leveled off. In contrast, higher NaOH concentrations increased the swelling ratio probably due to the alkaline induced degradation of dextran chains.

  17. Swelling and thermodynamic studies of temperature responsive 2-hydroxyethyl methacrylate/itaconic acid copolymeric hydrogels prepared via gamma radiation

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida L. J.; Mićić, Maja M.; Filipović, Jovanka M.; Suljovrujić, Edin H.

    2007-08-01

    The copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization. Swelling and thermodynamic properties of PHEMA and copolymeric P(HEMA/IA) hydrogels with different IA contents (2, 3.5 and 5 mol%) were studied in a wide pH and temperature range. Initial studies of so-prepared hydrogels show interesting pH and temperature sensitivity in swelling and drug release behavior. Special attention was devoted to temperature investigations around physiological temperature (37 °C), where small changes in temperature significantly influence swelling and drug release of these hydrogels. Due to maximum swelling of hydrogels around 40 °C, the P(HEMA/IA) hydrogel containing 5 mol% of IA without and with drug-antibiotic (gentamicin) were investigated at pH 7.40 and in the temperature range 25-42 °C, in order to evaluate their potential for medical applications.

  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.

  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. Scrotal Lymphangioma – A Rare Cause of Scrotal Swelling

    PubMed Central

    Nain Rattan, Kamal; S Malik, Vivek; Garsa, Vipin

    2013-01-01

    Lymphangioma is an extremely rare cause of scrotal swelling. We are reporting such a tumor in a one and half year old child presenting with a painless, progressive scrotal swelling. The mass was evaluated and excised completely. Histopathology confirmed it as Lymphangioma. PMID:23277887

  1. Swelling kinetics of microgels embedded in a polyacrylamide hydrogel matrix.

    PubMed

    Huang, Na; Guan, Ying; Zhu, X X; Zhang, Yongjun

    2014-06-23

    Composite hydrogels--macroscopic hydrogels with embedded microgel particles--are expected to respond to external stimuli quickly because microgels swell much faster than bulky gels. In this work, the kinetics of the pH-induced swelling of a composite hydrogel are studied using turbidity measurements. The embedded microgel is a pH- and thermosensitive poly(N-isopropylacrylamide-co-acrylic acid) microgel and the hydrogel matrix is polyacrylamide. A rapid pH-induced swelling of the embedded microgel particles is observed, confirming that composite hydrogels respond faster than ordinary hydrogels. However, compared with the free microgels, the swelling of the embedded microgel is much slower. Diffusion of OH(-) into the composite hydrogel film is identified as the main reason for the slow swelling of the embedded microgel particles, as the time of the pH-induced swelling of this film is comparable to that of OH(-) diffusion into the film. The composition of the hydrogel matrix does not significantly change the characteristic swelling time of the composite hydrogel film. However, the swelling pattern of the film changes with composition of the hydrogel matrix.

  2. Sex steroids inhibit osmotic swelling of retinal glial cells.

    PubMed

    Neumann, Florian; Wurm, Antje; Linnertz, Regina; Pannicke, Thomas; Iandiev, Ianors; Wiedemann, Peter; Reichenbach, Andreas; Bringmann, Andreas

    2010-04-01

    Osmotic swelling of glial cells may contribute to the development of retinal edema. We investigated whether sex steroids inhibit the swelling of glial somata in acutely isolated retinal slices and glial cells of the rat. Superfusion of retinal slices or cells from control animals with a hypoosmolar solution did not induce glial swelling, whereas glial swelling was observed in slices of postischemic and diabetic retinas. Progesterone, testosterone, estriol, and 17beta-estradiol prevented glial swelling with half-maximal effects at approximately 0.3, 0.6, 6, and 20 microM, respectively. The effect of progesterone was apparently mediated by transactivation of metabotropic glutamate receptors, P2Y1, and adenosine A1 receptors. The data suggest that sex steroids may inhibit cytotoxic edema in the retina.

  3. 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

  4. 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.

  5. 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.

  6. Swelling agent adopted decal transfer method for membrane electrode assembly fabrication

    NASA Astrophysics Data System (ADS)

    Cho, Doo Hee; Lee, So Young; Shin, Dong Won; Hwang, Doo Sung; Lee, Young Moo

    2014-07-01

    The decal transfer method is regarded as an effective membrane electrode assembly (MEA) fabrication method for industrial processes due to the improved adhesion between the catalyst layers and the hydrocarbon membrane. In this study, three swelling agents (ethanol, 1,5-pentanediol and glycerol) are introduced to the conventional decal methods in order to improve both the transfer ratio of electrodes on the membrane surface and the electrochemical properties. These swelling agents affect the surface energy differences between the swollen catalyst layer and the membrane substrate. Swelling agents also change the structure of the catalyst layer during the preparation (hot pressing) of the MEA. Changing the catalyst layer structure by introducing swelling agents diminishes the charge transfer resistance and internal resistances of MEAs. These improved electrochemical properties lead to the remarkably enhanced single cell performance of a SPAES MEA of 1380 mA cm-2 at 0.6 V, compared to a SPAES MEA fabricated by the conventional decal method (500 mA cm-2).

  7. 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.

  8. 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.

  9. The Mouse Murr1 Gene Is Imprinted in the Adult Brain, Presumably Due to Transcriptional Interference by the Antisense-Oriented U2af1-rs1 Gene

    PubMed Central

    Wang, Youdong; Joh, Keiichiro; Masuko, Sadahiko; Yatsuki, Hitomi; Soejima, Hidenobu; Nabetani, Akira; Beechey, Colin V.; Okinami, Satoshi; Mukai, Tsunehiro

    2004-01-01

    The mouse Murr1 gene contains an imprinted gene, U2af1-rs1, in its first intron. U2af1-rs1 shows paternal allele-specific expression and is transcribed in the direction opposite to that of the Murr1 gene. In contrast to a previous report of biallelic expression of Murr1 in neonatal mice, we have found that the maternal allele is expressed predominantly in the adult brain and also preferentially in other adult tissues. This maternal-predominant expression is not observed in embryonic and neonatal brains. In situ hybridization experiments that used the adult brain indicated that Murr1 gene was maternally expressed in neuronal cells in all regions of the brain. We analyzed the developmental change in the expression levels of both Murr1 and U2af1-rs1 in the brain and liver, and we propose that the maternal-predominant expression of Murr1 results from transcriptional interference of the gene by U2af1-rs1 through the Murr1 promoter region. PMID:14673161

  10. Chocolate swelling during storage caused by fat or moisture migration.

    PubMed

    Svanberg, L; Lorén, N; Ahrné, L

    2012-11-01

    Quantification of swelling in dark chocolate subjected to fat or moisture migration was conducted using a new method based on confocal chromatic displacement sensor. The nondestructive method allowed for the height profile of dark chocolate samples to be scanned with a sensitivity of ± 2.8 μm. By performing multiple scans on each sample prior to and after being subjected to fat or moisture migration, the induced swelling could be quantified. Applying the new method on confectionery systems revealed that fat and moisture migration generate different swelling behavior/kinetics in dark chocolate during storage. Moisture migration resulted in a rapid swelling once a water activity of 0.8 was reached in the chocolate, probably by interaction and absorption of moisture by the particulate solids. Fat migration also affected the swelling behavior in chocolate, possibly by inducing phase transitions in the continuous cocoa butter phase. Migrating fat also proved to induce a more pronounced swelling than the same amount of absorbed moisture which further consolidated that the observed swelling caused by fat or moisture migration is a result of significant different mechanisms.

  11. [Successful treatment for disseminated intra-vascular coagulation due to sepsis and brain abscess with low molecular weight heparin in a patient with antiphospholipid syndrome].

    PubMed

    Hiroishi, K; Shigenobu, Y; Asai, M; Tsuzuki, Y; Hayashi, N; Tominaga, K; Matsui, K; Hada, T; Higashino, K

    1999-02-01

    The management of disseminated intravascular coagulation (DIC) in a 22-year-old female patient with antiphospholipid syndrome is reported. Gabexate mesilate was given by continuous drip infusion at 1.5 g/day. No effect was seen, therefore Dalteparin sodium (DS) was administered by continuous drip infusion at 70 U/kg/day. The DIC score improved gradually during the first 4 days to normalization by 10 days. However, convulsive seizure was developed. Computed tomographic scan of brain demonstrated brain abscess at lt-basal ganglia. Continuous drainage was performed while administered continuous drip infusion of DS. Follow-up CT after operation showed reduction of low density area which means brain abscess. Finding in this case suggest that DS may play a role in the management of DIC accompanying intracranial infection.

  12. Drainage and Landscape Evolution in the Bighorn Basin Accompanying Advection of the Yellowstone Hotspot Swell Through North America

    NASA Astrophysics Data System (ADS)

    Guerrero, E. F.; Meigs, A.

    2012-12-01

    basin is an ideal location to quantify long wavelength dynamic topography due to its low relief. Long river profiles streams that are transverse to the topographic swell in the basin suggest a transient advective signal preserved as profile knickpoints. Abandoned strath terraces, stream piracy, drainage reorganization, and lateral channel migration within the Bighorn Basin are all consistent indicators of the advection of a topographic swell. However, the lack of a high-resolution absolute age chronology precludes us from attributing the primary landscape and drainage forcing to climate change or dynamic topography. Our future work will focus on the timing of geomorphic and river profile evolution to disentangle competing effects of topographic advection, climate, and other factors.

  13. Enhanced resistance of CXCR3 deficient mice to ocular HSV-1 infection is due to control of replication in the brain ependyma.

    PubMed

    Kroll, Chandra M; Zheng, Min; Carr, Daniel J J

    2014-11-15

    CXCR3 deficient (CXCR3(-/-)) mice are resistant to ocular HSV-1 infection in that less mice develop encephalitis and succumb to infection in comparison to wild type (WT) animals. A region of the brain previously identified to be crucial for development of encephalitis was evaluated in HSV-1-infected CXCR3(-/-) and WT mice. In this region, known as the ependyma, viral titer, infiltrating leukocyte populations, and key anti-viral cytokine message levels were evaluated. We found that CXCR3(-/-) mice possessed significantly less HSV-1 and expressed significantly more IFN-β mRNA in the brain ependyma compared to WT animals during the development of encephalitis.

  14. Orbital sarcoidosis presenting as diffuse swelling of the lower eyelid.

    PubMed

    Lee, Jeong Kyu; Moon, Nam Ju

    2013-02-01

    The author reports a case of orbital Sarcoidosis in a 70-year-old female that initially presented as diffuse swelling of the lower eyelid. The patient complained of painless swelling of the left lower lid without palpable mass, and a computerized tomography (CT) scan of the orbit was unremarkable. A serum angiotensin converting enzyme level was elevated, and hilar lymphadenopathy was noted on the chest CT. The patient underwent surgical debulking for histologic confirmation, which led to a final diagnosis of sarcoidosis involving the orbital fat. Unexplained chronic eyelid swelling without a mass should be considered a possible ophthalmic manifestation of orbital sarcoidosis.

  15. 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.

  16. Dosimetric effects of swelling or shrinking tissue during helical tomotherapy breast irradiation: A phantom study.

    PubMed

    Klepper, Rudolf; Höfel, Sebastian; Botha, Ulrike; Köhler, Peter; Zwicker, Felix

    2014-07-08

    During radiation therapy of the female breast, the actual target volume compared to the planning target volume may change due to swelling or shrinking of the tissue. Under- or overdosage is to be expected, especially when performing IMRT or tomotherapy techniques. The objective of this study is to develop a model-based quantification of these dose effects, with a particular focus on the changes in the surface dose. A cylindrical phantom was used as an artificial surrogate of the human torso. By adding and removing Superflab layers of various thicknesses, both radial breast swelling and shrinking could be simulated. The effects on dose distribution were evaluated using film dosimetry. The results were compared to dose calculations. To estimate the true surface doses, we subtracted the influence of the film material on air measurements. During a swelling of 5, 10, and 15 mm, the planning target volume was consistently underdosed by 2%, 5%, and 7% of the prescribed dose, respectively. Swelling led to reduced dose values of up to 72%, 55%, and 50% at the outer edge of the actual target volume. The measured surface dose decreased successively from 31% to 23%. During shrinking, the dose in the planning target volume increased successively from 100% to 106%. The measured surface doses increased from 29% to 36%. The calculated dose values agreed with the measured values within error limits. During radiotherapy of the female breast, new planning appears to be essential for radial tissue swelling of 5 mm or more because of severe underdosing. Shrinking leads to moderate overdosing and an increased surface dose. In addition, caution is advised when removing bolus material with respect to the planned situation.

  17. Dosimetric effects of swelling or shrinking tissue during helical tomotherapy breast irradiation. A phantom study.

    PubMed

    Klepper, Rudolf; Höfel, Sebastian; Botha, Ulrike; Köhler, Peter; Zwicker, Felix

    2014-07-01

    During radiation therapy of the female breast, the actual target volume compared to the planning target volume may change due to swelling or shrinking of the tissue. Under- or overdosage is to be expected, especially when performing IMRT or tomotherapy techniques. The objective of this study is to develop a model-based quantification of these dose effects, with a particular focus on the changes in the surface dose. A cylindrical phantom was used as an artificial surrogate of the human torso. By adding and removing Superflab layers of various thicknesses, both radial breast swelling and shrinking could be simulated. The effects on dose distribution were evaluated using film dosimetry. The results were compared to dose calculations. To estimate the true surface doses, we subtracted the influence of the film material on air measurements. During a swelling of 5, 10, and 15 mm, the planning target volume was consistently underdosed by 2%, 5%, and 7% of the prescribed dose, respectively. Swelling led to reduced dose values of up to 72%, 55%, and 50% at the outer edge of the actual target volume. The measured surface dose decreased successively from 31% to 23%. During shrinking, the dose in the planning target volume increased successively from 100% to 106%. The measured surface doses increased from 29% to 36%. The calculated dose values agreed with the measured values within error limits. During radiotherapy of the female breast, new planning appears to be essential for radial tissue swelling of 5 mm or more because of severe underdosing. Shrinking leads to moderate overdosing and an increased surface dose. In addition, caution is advised when removing bolus material with respect to the planned situation. PACS numbers: 87.53.Bn, 87.55.dk, 87.55.D.

  18. 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.

  19. Controlling the swelling and wettability of weak polyelectrolyte brushes

    NASA Astrophysics Data System (ADS)

    Gurtowski, Richard; Jing, Benxin; Zhu, Elaine

    2011-03-01

    Weak polyelectrolytes (PE) of tunable ionization shows great potential as ``smart'' polymer materials for diverse applications from drug delivery to energy storage. However, the conformational dynamics of surfaced-tethered weak PE chains remain inadequately understood due to the complexity of their dynamic charge states in response to solvation and surface immobilization conditions. In this work, we investigate the wetting and swelling characteristics of poly(2-vinyl pyridine) (P2VP) brushes grafted to a gold substrate by AFM and water contact angle measurements. We observe the collapse of P2VP brushes, accompanied with increased surface hydrophobicity, as increasing solution pH across a critical transition pH, which is considerably lower than the pKa of free P2VP chains in bulk solution. Surprisingly, the broadness of the transition pH range shows a strong dependence with brush thickness, but not grafting density, suggesting a distribution of chain ionization along grafted P2VP brushes. We further manipulate P2VP brush structures by applying ac-electric fields across the brushes to make tunable and switchable polymer surfaces.

  20. Serum albumin induces osmotic swelling of rat retinal glial cells.

    PubMed

    Löffler, Silvana; Wurm, Antje; Kutzera, Franziska; Pannicke, Thomas; Krügel, Katja; Linnertz, Regina; Wiedemann, Peter; Reichenbach, Andreas; Bringmann, Andreas

    2010-03-04

    Edema in the ischemic neural tissue develops by increased vascular permeability associated with extravasation of albumin, and by glial swelling. Here, we show that bovine serum albumin acutely administered to slices of the rat retina causes swelling of glial somata under hypoosmotic conditions. The effect of albumin was dose-dependent, with half-maximal and maximal effects at 10 nM and 1 microM, respectively, and was mediated by activation of transforming growth factor-beta receptor type II, oxidative stress, and the production of arachidonic acid and prostaglandins. Albumin-induced glial swelling was prevented by glutamate and purinergic receptor agonists. The data suggest that serum albumin may induce glial swelling in the presence of osmotic gradients.

  1. Coupled Hydro-Mechanical Model of Bentonite Hydration and Swelling

    NASA Astrophysics Data System (ADS)

    Hancilova, Ilona; Hokr, Milan

    2016-10-01

    This paper deals with the modelling of coupled hydro-mechanical processes at the buffer and host rock interface (bentonite and granite) in the context of the safe disposal of spent nuclear fuel. Granite, as one of the barriers, includes fractures which are the source for hydration of bentonite and its subsequent swelling. It affects the mechanical behaviour and possibly the stability of the whole system. A non-linear solution for the stress-deformation problem with swelling was developed. This solution is coupled with the non-linear diffusion problem (for unsaturated flow). The swelling is defined using a coefficient dependent on water content according to literature data, with the effective Young's modulus decreasing close to zero corresponding to the plastic state. Results confirm the expected non-uniform saturation, swelling, and stresses in bentonite and small contribution to a fracture displacement.

  2. 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.

  3. Mechanically Robust, Negative-Swelling, Mussel-Inspired Tissue Adhesives

    PubMed Central

    Barrett, Devin G.; Bushnell, Grace G.

    2013-01-01

    Most synthetic polymer hydrogel tissue adhesives and sealants swell considerably in physiologic conditions, which can result in mechanical weakening and adverse medical complications. Herein, we describe the synthesis and characterization of mechanically tough zero- or negative-swelling mussel-inspired surgical adhesives based on catechol-modified amphiphilic poly(propylene oxide)-poly(ethylene oxide) block copolymers. The formation, swelling, bulk mechanical, and tissue adhesive properties of the resulting thermosensitive gels were characterized. Catechol oxidation at or below room temperature rapidly resulted in a chemically cross-linked network, with subsequent warming to physiological temperature inducing a thermal hydrophobic transition in the PPO domains and providing a mechanism for volumetric reduction and mechanical toughening. The described approach can be easily adapted for other thermally sensitive block copolymers and cross-linking strategies, representing a general approach that can be employed to control swelling and enhance mechanical properties of polymer hydrogels used in a medical context. PMID:23184616

  4. 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

  5. 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.

  6. The Effect of Elasticityon the Extrudate Swell of Molten Polymers

    NASA Astrophysics Data System (ADS)

    Hatzikiriakos, Savvas; Konaganti, Vinod Kumar; UBC Team

    2016-11-01

    The extrudate swell of an industrial grade high molecular weight high-density polyethylene (HDPE) in capillary dies is studied using the integral K-BKZ constitutive model. The non-linear viscoelastic flow properties of the polymer resin are studied for a broad range of large step shear strains and high shear rates using the cone partitioned plate (CPP) geometry of the stress/strain controlled rotational rheometer. This allowed the determination of the rheological parameters accurately, in particular the damping function, which is proven to be the most important in simulating transient flows such as extrudate swell. A series of simulations performed using the integral K-BKZ Wagner model with different values of the Wagner exponent n, ranging from n = 0.15 to 0.5, demonstrates that the extrudate swell predictions are extremely sensitive to the Wagner damping function exponent. Using the correct n - value resulted in extrudate swell predictions that are in excellent agreement with experimental measurements. .

  7. Swelling of ultrathin crosslinked polyamide water purification membranes

    NASA Astrophysics Data System (ADS)

    Chan, Edwin; Stafford, Christopher

    2013-03-01

    Polyamide (PA) ultrathin films represent the state-of-the-art nanofiltration and reverse osmosis membranes used in water desalination. The performance of these materials, such as permselectivity, is intimately linked with extent of swelling of the PA network. Thus, quantifying their swelling behavior would be a useful and simple route to understanding the specific network structural parameters that control membrane performance. In this work, we measure the swelling behavior of PA ultrathin films using X-ray reflectivity as a function of water hydration. By applying the Flory-Rehner theory used to describe the swelling behavior of polymer networks, we quantify the PA network properties including Flory interaction parameter and the monomer units between crosslinks. Finally, we demonstrate application of this measurement approach for characterizing the network properties of different types of PA ultrathin films relevant to water purification and discuss the relationship between network and transport properties. Materials Science and Engineering Division

  8. 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.

  9. 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...

  10. Swell and Sea in the Emerging Arctic Ocean

    DTIC Science & Technology

    2014-01-01

    GeophysicalResearchLetters RESEARCHLETTER 10.1002/2014GL059983 Key Points: • Surface waves in the Arctic Ocean increase during periods of sea ice ...fetch in the Arctic , because the swell is regionally driven. This suggests that further reductions in seasonal ice cover in the future will result in... ice sea swell Figure 2. Time series of Arctic Ocean wave conditions. Hourly values for (a) significant wave height, (b) wind speed at 10 m reference

  11. Labial swelling: a rare presentation of pubic bone tuberculosis.

    PubMed

    Shende, Prajakta; Gandhewar, Manisha; Gaikwad, Pradip; Nanaware, Sandip; Risbud Joshi, Prachi

    2016-09-14

    Tuberculosis (TB), being a global health problem, represents variedly. Its presentation as a labial swelling secondary to pubic bone TB has been reported rarely in literature. We report a case of pubic bone TB presenting as a labial swelling in a woman of reproductive age. Early diagnosis with fine needle aspiration cytology, acid-fast bacillus (AFB) staining, AFB culture and magnetic resonance imaging with early initiation of treatment resulted in a favourable outcome.

  12. The Effects of Iron Oxidation State on Clay Swelling,

    DTIC Science & Technology

    1983-03-07

    swelling, montmorillonite , nontronite, smectite, water, DLVO theory, surface charge, dissolution, methods, aluminum, silicon, inert atmosphere. 2G...that many physical properties of bulk water are changed when it is adsorbed between layers of Na4- montmorillonite (e.g., Oster and Low, 1964; Kolaian...Na+- montmorillonite accounted for about 13% of the total water content in the free-swelling state. We can therefore express the total water content

  13. Cytotoxic edema: mechanisms of pathological cell swelling

    PubMed Central

    Liang, Danny; Bhatta, Sergei; Gerzanich, Volodymyr; Simard, J. Marc

    2009-01-01

    Cerebral edema is caused by a variety of pathological conditions that affect the brain. It is associated with two separate pathophysiological processes with distinct molecular and physiological antecedents: those related to cytotoxic (cellular) edema of neurons and astrocytes, and those related to transcapillary flux of Na+ and other ions, water, and serum macromolecules. In this review, the authors focus exclusively on the first of these two processes. Cytotoxic edema results from unchecked or uncompensated influx of cations, mainly Na+, through cation channels. The authors review the different cation channels that have been implicated in the formation of cytotoxic edema of astrocytes and neurons in different pathological states. A better understanding of these molecular mechanisms holds the promise of improved treatments of cerebral edema and of the secondary injury produced by this pathological process. PMID:17613233

  14. 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.

  15. Field-Based Mantle Rheometry over the Hawaiian Swell

    NASA Astrophysics Data System (ADS)

    Ribe, N. M.; Asaadi, N.; Sobouti, F.

    2011-12-01

    Depending on their physical and chemical conditions, mantle rocks can deform either by diffusion creep (with a linear relationship between strain rate ˙ {ɛ } and stress &sigma) or by nonlinear dislocation creep. However, reliable maps showing where in the mantle each of these mechanisms is dominant are difficult to construct, primarily because standard geodynamical, seismological, and mineral physics methods for inferring mantle rheology are indirect. It is therefore desirable to identify regions where the operative deformation mechanism can be inferred directly from surface geophysical observations alone. We suggest that one such region is the uppermost mantle beneath the Hawaiian swell. We identify a new observable quantity, the rate of downstream decay of the swell topography, that depends only on the value of the exponent n in the rheological law ˙ {ɛ }∝σ n of the low-density material compensating the swell. Fluid-mechanical models for the lateral spreading of that material show that the swell topography decays as the downstream distance to the power -1/(3n + 2), indicating that the decay rate is a sensitive rheological probe. Quantitative comparison of the observed swell topography with the model predictions shows that the swell's shape is poorly explained by diffusion creep, and requires a dislocation creep rheology. The rheology inferred from the comparison is reasonably compatible with laboratory deformation data for both olivine and clinopyroxene.

  16. Rapid Eye Movement Sleep Deprivation Associated Increase in Na-K ATPase Activity in the Rat Brain is Due to Noradrenaline Induced α1-Adrenoceptor Mediated Increased α-Subunit of the Enzyme.

    PubMed

    Amar, Megha; Mallick, Birendra Nath

    2015-08-01

    Rapid eye movement sleep (REMS) modulates Na-K ATPase activity and maintains brain excitability. REMS deprivation (REMSD)-associated increased Na-K ATPase activity is mediated by noradrenaline (NA) acting on α1-adrenoceptor (AR) in the brain. It was shown that NA-induced increased Na-K ATPase activity was due to allosteric modulation as well as increased turnover of the enzyme. Although the former has been studied in detail, our understanding on the latter was lacking, which we have studied. Male Wistar rats were REMS deprived for 4-days by classical flower-pot method; suitable control experiments were conducted. In another set, α1-AR antagonist prazosin (PRZ) was i.p. injected 48 h REMSD onward. At the end of experiments rats were sacrificed by cervical dislocation and brains were removed. Synaptosomes prepared from the brains were used to estimate Na-K ATPase activity as well as protein expressions of different isoforms of the enzyme subunits using western blot. REMSD significantly increased synaptosomal Na-K ATPase activity and that was due to differential increase in the expressions of α1-, α2- and α3-isoforms, but not that of β1- and β2-isoforms. PRZ reduced the REMSD-induced increased Na-K ATPase activity and protein expressions. We also observed that the increased Na-K ATPase subunit expression was not due to enhanced mRNA synthesis, which suggests the possibility of post-transcriptional regulation. Thus, the findings suggest that REMSD-associated increased Na-K ATPase activity is due to elevated level of α-subunit of the enzyme and that is induced by NA acting on α1-AR mediated mRNA-stabilization.

  17. Partial trisomy due to a de novo duplication 22q11.1-22q13.1: a cat-eye syndrome variant with brain anomalies.

    PubMed

    Karcaaltincaba, D; Ceylaner, S; Ceylaner, G; Dalkilic, S; Karli-Oguz, K; Kandemir, O

    2010-01-01

    We report a case of partial trisomy 22q with de novo duplication of chromosomal region 22q11.1-22q13.1, also confirmed by microarray comparative genomic hybridization (Array-CGH) analysis. The fetus had interhemispheric cyst and corpus callosum agenesis diagnosed by MRI which has not been reported in the literature. This novel phenotype differs from the reported cat eye syndromes by the absence of heart defects and the presence of brain anomalies.

  18. Influence of swelling on water transport through PVA-based membrane

    NASA Astrophysics Data System (ADS)

    Praptowidodo, Veronica S.

    2005-04-01

    Dehydration of ethanol is studied using various PVA-based membranes. Due to its high solubility in water, PVA membrane has a great extent of swelling in ethanol-water mixture, resulting in a remarkable decline of selectivity. To restrict the extent of swelling, PVA membranes were chemically modified by crosslinking reaction by glutaraldehyde. Crosslinking reaction was conducted by using two concentrations of glutaraldehyde, i.e. 0.025 and 0.100% by weight, and the degree of crosslinking was varied by changing the reaction time. The difference degree of crosslinking was examined by the extent of swelling. Those modified membranes were performed by pervaporation to study the effect of crosslinking on separation process. Crosslinked PVA-membrane with 26.5% swelling degree, produced flux 0.28 kg/m 2 h, and separation factor 104 at the condition of pervaporation at 40 °C and 0.4 mbar downstream pressure, using feed solution 90 wt% of ethanol. The present of charged groups in PVA-N and PVA-It membranes decrease the swelling degree to 15.65 and 14.00%, respectively. At feed concentration of ethanol 96% by pervaporation, PVA membrane with swelling degree 26.5%, produced flux, J=0.279 kg/m 2 h and separation factor, α=107; PVA-N membrane flux, J=0.123 kg/m 2 h and separation factor, α=216; PVA-It membrane flux, J=0.119 kg/m 2 h and separation factor, α=228. The present of charged groups increase selectivity, however it decrease flux. By decreasing down stream pressure from 0.4 to 0.14 mbar at the same pervaporation condition, the membrane selectivity changed to a higher values, PVA membrane flux, J=0.189 kg/m 2 h and separation factor, α=335; PVA-N membranes flux, J=0.089 kg/m 2 h and separation factor α=709; PVA-It membranes flux, J=0.086 kg/m 2 h and separation factor α=837. The presence of charged groups in polymers and the down stream pressure influence potentially to improve membrane selectivity. Substitution of anionic and cationic charged groups to PVA

  19. 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

  20. Reduced grey matter metabolism due to white matter edema allows optimal assessment of brain tumors on 18F-FDG-PET.

    PubMed

    Pourdehnad, Michael; Basu, Sandip; Duarte, Paulo; Okpaku, Aubrey S; Saboury, Babak; Hustinx, Roland; Alavi, Abass

    2011-01-01

    The main aim of this research was to demonstrate that the cortical and subcortical grey matter hypometabolism as revealed by fluorine-18 fluorodesoxyglucose-positron emission tomography ((18)F-FDG-PET) imaging in brain tumors is related to associated edema as demonstrated by magnetic resonance imaging (MRI). This in turn enhances the ability to assess disease activity in the tumor and the degree of loss of cerebral function in the adjacent and distant structures. We evaluated brain T1 and T2 weighted MRI and (18)F-FDG-PET scans of 29 patients (19 adult, 10 pediatric) with history of brain tumor. Tumor histology types included 21 gliomas, 1 melanoma, 1 primitive neuroectodermal tumor, 3 medulloblastomas and 3 ependymomas. The majority of scans were performed within the same week (94% <1 month. The extent of hypo and hypermetabolism was assessed on the (18)F-FDG-PET scans. A template of 12 regions of interest (ROI) was applied and the laterality indices of the regional counts (signal intensity) were computed. Extent of edema, enhancement, and anatomical change were assessed on the MRI scans. Extent of edema in the same ROI was evaluated by a 6-point semiquantitative scale and laterality indices were generated. Metabolic activity of the grey matter was correlated with the extent of edema using these indices. In all cases where edema was present, significant hypometabolism was observed in the adjacent structures. Overall, there was a strong correlation between the extent of edema and severity of hypometabolism (r=0.92, P=0.01). This was true regardless of the location of edema, whether there was history of radiation treatment (r=0.91, P=0.03), or not (r=0.97, P=0.17). In conclusion, edema independent of underlying variables appeared to contribute significantly to cortical and sub-cortical grey matter hypometabolism observed in patients with brain tumors. This would indicate that brain tumors can be successfully assessed by (18)F-FDG-PET and therefore the efforts for

  1. 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

  2. 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

  3. What can asymmetry tell us? Investigation of asymmetric versus symmetric pinch and swell structures in nature and simulation

    NASA Astrophysics Data System (ADS)

    Gardner, Robyn; Piazolo, Sandra; Daczko, Nathan

    2015-04-01

    Pinch and swell structures occur from microscopic to landscape scales where a more competent layer in a weaker matrix is deformed by pure shear, often in rifting environments. The Anita Shear Zone (ASZ) in Fiordland, New Zealand has an example of landscape scale (1 km width) asymmetric pinch and swell structures developed in ultramafic rocks. Field work suggests that the asymmetry is a result of variations in the surrounding 'matrix' flow properties as the ultramafic band is surrounded to the east by an orthogneiss (Milford Orthogneiss) and to the west by a paragneiss (Thurso Paragneiss). In addition, there is a narrow and a much wider shear zone between the ultramafics and the orthogneiss and paragneiss, respectively. Detailed EBSD analysis of samples from a traverse across the pinch and swell structure indicate the ultramafics in the shear zone on the orthogneiss side have larger grain size than the ultramafics in the shear zone on the paragneiss side. Ultramafic samples from the highly strained paragneiss and orthogneiss shear zones show dislocation creep behaviour, and, on the paragneiss side, also significant deformation by grain boundary sliding. To test if asymmetry of pinch and swell structures can be used to derive the rheological properties of not only the pinch and swell lithologies, but also of the matrix, numerical simulations were performed. Numerical modelling of pure shear (extension) was undertaken with (I) initially three layers and then (II) five layers by adding soft high strain zones on both sides of the rheological hard layer. The matrix was given first symmetric, then asymmetric viscosity. Matrix viscosity was found to impact the formation of pinch and swell structures with the weaker layer causing increased tortuosity of the competent layer edge due to increased local differential stress. Results highlight that local, rheologically soft layers and the relative viscosity of matrix both impact significantly the shape and symmetry of developing

  4. 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.

  5. Dynamics of Swelling and Drying in a Spherical Gel

    NASA Astrophysics Data System (ADS)

    Bertrand, Thibault; Peixinho, Jorge; Mukhopadhyay, Shomeek; MacMinn, Christopher W.

    2016-12-01

    Swelling is a volumetric-growth process in which a porous material expands by spontaneous imbibition of additional pore fluid. Swelling is distinct from other growth processes in that it is inherently poromechanical: local expansion of the pore structure requires that additional fluid be drawn from elsewhere in the material, or into the material from across the boundaries. Here, we study the swelling and subsequent drying of a sphere of hydrogel. We develop a dynamic model based on large-deformation poromechanics and the theory of ideal elastomeric gels, and we compare the predictions of this model with a series of experiments performed with polyacrylamide spheres. We use the model and the experiments to study the complex internal dynamics of swelling and drying, and to highlight the fundamentally transient nature of these strikingly different processes. Although we assume spherical symmetry, the model also provides insight into the transient patterns that form and then vanish during swelling as well as the risk of fracture during drying.

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

    PubMed

    Nestle, Nikolaus; Häberle, Karl

    2009-11-03

    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.

  7. Generation of continental rifts, basins, and swells by lithosphere instabilities

    NASA Astrophysics Data System (ADS)

    Fourel, LoïC.; Milelli, Laura; Jaupart, Claude; Limare, Angela

    2013-06-01

    Continents may be affected simultaneously by rifting, uplift, volcanic activity, and basin formation in several different locations, suggesting a common driving mechanism that is intrinsic to continents. We describe a new type of convective instability at the base of the lithosphere that leads to a remarkable spatial pattern at the scale of an entire continent. We carried out fluid mechanics laboratory experiments on buoyant blocks of finite size that became unstable due to cooling from above. Dynamical behavior 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 interior region. In the outer annulus, upwellings and downwellings take the form of periodically spaced radial spokes. The interior region hosts the more familiar convective pattern of polygonal cells. In 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. Simple scaling laws for the dimensions and spacings of the convective structures are derived. For the subcontinental lithospheric mantle, these dimensions 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.

  8. [A pathogenetic hypothesis based on the use of chlorpromazine of organic disorders probably due to microcirculatory changes].

    PubMed

    Malossi, M

    1993-01-01

    In the introduction it is noted that, in the physiopathology, specific pathogenetic elements are missing concerning irritative stimulation, turbid fat pathosis, digital hippocratism of chronic affections (for example, pulmonary affections), the most frequent onset of telarche and of the swelling of the areola of the breast on the left hemithorax in the premenstrual syndrome, fibrosis, cyrrosis, certain types of insipid diabetes, etc. In the opinion of the author, the use of chloropromazine, in doses that have proved to be harmless, has contributed to the clearing up of some questions concerning a few pathologies of internal organs: the liver, the spleen, the brain-and enable us to pose some hypotheses about the swelling of the liver, the origin of scleroses and cirrhoses and some splenic and encephalic swellings. The author suggests that the fundamental reason is to be sought in changes in the microcirculation which are linked to insufficient capillary and sinusoidal circulation. Two cases of insipid diabetes are mentioned which were treated with chloropromazine and for which an improvement in the trophism of the diencephalic cells was hypothesized, due to an improvement in the local circulation. A similar physiopathological microcirculatory behaviour is attributed to digital hippocratism, the P. Marie and Bamberger syndrome (similar to those determined by cyanotic congenital cardiopathies), both due to chronic suppurative processes, and the slightly more frequent onset of telarche on the left hemithorax. It is expected that other pathologies may be explained by a similar physiopathological mechanism, malignant tumor inclusive.

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

    NASA Astrophysics Data System (ADS)

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

    Swelling values have been determined for a set of commercial alloys irradiated to a peak fluence of 1.8 × 10 23 n/cm 2 (E >0.1 MeV) over the temperature range of 400 to 650°C. The alloys studied fall into three classes: the ferritic alloys AISI 430F, AISI 416, EM-12, H-11 and 2 {1}/{4}Cr-1Mo; the superalloys Inconel 718 and Inconel X-750; and the refractory alloys TZM and Nb-1Zr. All of these 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.

  10. 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.

  11. 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.

  12. OXIDATIVE PHOSPHORYLATION IN MITOCHONDRIA FROM LIVERS SHOWING CLOUDY SWELLING

    PubMed Central

    Fonnesu, Alberto; Severi, Clara

    1956-01-01

    Using succinate and α-ketoglutarate as substrates, oxidative phosphorylation has been measured in mitochondria isolated from livers showing cloudy swelling. This cellular change was obtained by injecting rats with S. typhi murium toxin and guinea pigs with diphtheria toxin. It has been found that phosphorylation associated with the oxidation of either of these substrates was partially inhibited in mitochondria from livers showing cloudy swelling, while the oxygen consumption was unchanged. Thus, the P:O ratios for both succinate and α-ketoglutarate were lower in mitochondria from treated animals than they were in normal mitochondria. Dephosphorylation of ATP was not significantly modified in mitochondria from livers showing cloudy swelling as compared with normal controls. No dephosphorylation of AMP and G-6-P was observed either in normal mitochondria or in mitochondria from treated animals. PMID:13331961

  13. Extracellular norepinephrine, norepinephrine receptor and transporter protein and mRNA levels are differentially altered in the developing rat brain due to dietary iron deficiency and manganese exposure.

    PubMed

    Anderson, Joel G; Fordahl, Steven C; Cooney, Paula T; Weaver, Tara L; Colyer, Christa L; Erikson, Keith M

    2009-07-24

    Manganese (Mn) is an essential trace element, but overexposure is characterized by Parkinson's like symptoms in extreme cases. Previous studies have shown that Mn accumulation is exacerbated by dietary iron deficiency (ID) and disturbances in norepinephrine (NE) have been reported. Because behaviors associated with Mn neurotoxicity are complex, the goal of this study was to examine the effects of Mn exposure and ID-associated Mn accumulation on NE uptake in synaptosomes, extracellular NE concentrations, and expression of NE transport and receptor proteins. Sprague-Dawley rats were assigned to four dietary groups: control (CN; 35 mg Fe/kg diet), iron-deficient (ID; 6 mg Fe/kg diet), CN with Mn exposure (via the drinking water; 1 g Mn/L) (CNMn), and ID with Mn (IDMn). (3)H-NE uptake decreased significantly (R=-0.753, p=0.001) with increased Mn concentration in the locus coeruleus, while decreased Fe was associated with decreased uptake of (3)H-NE in the caudate putamen (R=0.436, p=0.033) and locus coeruleus (R=0.86; p<0.001). Extracellular concentrations of NE in the caudate putamen were significantly decreased in response to Mn exposure and ID (p<0.001). A diverse response of Mn exposure and ID was observed on mRNA and protein expression of NE transporter (NET) and alpha(2) adrenergic receptor. For example, elevated brain Mn and decreased Fe caused an approximate 50% decrease in NET and alpha(2) adrenergic receptor protein expression in several brain regions, with reductions in mRNA expression also observed. These data suggest that Mn exposure results in a decrease in NE uptake and extracellular NE concentrations via altered expression of transport and receptor proteins.

  14. Water uptake and swelling in single trabeculæ from human femur head

    PubMed Central

    Marinozzi, Franco; Bini, Fabiano; Marinozzi, Andrea

    2014-01-01

    The swelling of air-dried single trabeculae from human femur heads was obtained by complete immersion in water and the dimensional changes of the samples were measured over time. The experimental results were analyzed under the viewpoint of the diffusion through a porous material. The dimensional changes of the single trabeculae were 0.26 ± 0.15 percent (length), 0.45 ± 0.25 percent (width) and 1.86 ± 0.97 percent (thickness). The diffusion coefficients were then calculated from the swelling recorded over time and a value of (4.12 ± 0.8) x 10−10(m2s−1) (mean ± standard deviation) was found.   Since the dimensional variations of the specimens is due to the swelling of the collagen bone matrix, this technique could offer new insights for (1) a selective characterization of bone microstructure at the collagen matrix level and (2) the dynamics of diffusion through bone tissue. PMID:24553097

  15. 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%.

  16. The theory of degassing and swelling of a supersaturated-by-gas solution

    NASA Astrophysics Data System (ADS)

    Kuchma, A. E.; Shchekin, A. K.; Bulgakov, M. Yu.

    2017-02-01

    The kinetic theory of degassing and swelling of a supersaturated-by-gas liquid solution under decompression has been formulated. The theory is based on the extended excluded volume approach to kinetics of gas-bubble nucleation. A description of the nucleation stage of supercritical gas-bubble formation with nonstationary nonuniform diffusion shells around the bubbles and mean-field mixing of the dissolved gas concentration at outer parts of the shells due to their stochastic overlapping has been built. In this way, the theory embraces the cases with any degree of initial gas supersaturation and deviation from the steady-state diffusion. It has been shown that the effects of nonstationary diffusion may be very significant in the growth of bubbles and, in particular, are responsible for a significant swelling of a supersaturated-by-gas liquid solution. Distribution of supercritical bubbles in sizes and gas concentration profiles at any moment of the nucleation stage as well as duration of the nucleation stage and the swelling ratio at the end of nucleation stage have been found.

  17. Space-time structure of long ocean swell fields

    NASA Astrophysics Data System (ADS)

    Delpey, Matthias T.; Ardhuin, Fabrice; Collard, Fabrice; Chapron, Bertrand

    2010-12-01

    The space-time structure of long-period ocean swell fields is investigated, with particular attention given to features in the direction orthogonal to the propagation direction. This study combines space-borne synthetic aperture radar (SAR) data with numerical model hindcasts and time series recorded by in situ instruments. In each data set the swell field is defined by a common storm source. The correlation of swell height time series is very high along a single great circle path with a time shift given by the deep water dispersion relation of the dominant swells. This correlation is also high for locations situated on different great circles in entire ocean basins. Given the Earth radius R, we define the distance from the source Rα and the transversal angle β so that α and β would be equal the colatitude and longitude for a storm centered on the North Pole. Outside of land influence, the swell height field at time t, Hss(α, β,t) is well approximated by a function Hss,0(t - Rα/Cg)/? times another function r2 (β), where Cg is a representative group speed. Here r2 (β) derived from SAR data is very broad, with a width at half the maximum that is larger than 70°, and varies significantly from storm to storm. Land shadows introduce further modifications so that in general r2 is a function of β and α. This separation of variables and the smoothness of the Hss field, allows the estimation of the full field of Hss from sparse measurements, such as wave mode SAR data, combined with one time series, such as that provided by a single buoy. A first crude estimation of a synthetic Hss field based on this principle already shows that swell hindcasts and forecasts can be improved by assimilating such synthetic observations.

  18. Swelling behavior of a simple ferritic alloy. [Fe-10% Cr

    SciTech Connect

    Horton, L.L.; Bentley, J.

    1983-01-01

    The swelling behavior which results from simulated fusion environment irradiation of Fe-10% Cr has been characterized with transmission electron microscopy. Specimens were bombarded at 850 K with: a triple-beam of He/sup +/, D/sup +//sub 2/, and 4 MeV Fe/sup + +/ ions to 0.3, 1, 3, 10, 30, and 100 dpa, a dual-beam of He/sup +/ and 4 MeV Fe/sup + +/ ions to 30 and 100 dpa; and a single-beam of 4 MeV Fe/sup + +/ ions to 30 dpa. The helium and hydrogen injection rates were approx. 10 appm He/dpa and approx. 40 appm D/dpa. Cavities were observed for damage levels of 3 dpa and greater. The swelling was <0.1% for damage levels <30 dpa, but at 100 dpa, there was an increase in the swelling to 2.5% for the triple-beam irradiation and 1.2% for the dual-beam irradiation. The swelling rates between 30 and 100 dpa correlate well with calculated values assuming a steady-state swelling-rate regime has been reached. Calculations show the rapid cavity growth associated with this swelling increase cannot be attributed to equilibrium bubble growth. For all of the bombardments, the cavities with a diameter greater than 10 nm had a truncated octahedral morphology with (111) facets and (100) truncations. Measurements indicate that the surface energy relationship was ..gamma../sub 111/approx. =0.8 ..gamma../sub 100/ for these cavities. At 30 dpa, the cavities in the specimen irradiated with the single-beam technique were larger and had a lower concentration than the specimens irradiated with specimens irradiated with the dual- and triple-ion beams suggests that deuterium has an effect on the damage microstructures in Fe-10% Cr.

  19. 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.

  20. Strategies used to inhibit postoperative swelling following removal of impacted lower third molar

    PubMed Central

    Sortino, Francesco; Cicciù, Marco

    2011-01-01

    Postoperative swelling following different surgical strategies is an area of great interest. The main part of literature on the topic deals with swelling after extraction of low impacted third molar. In this review, we have analyzed publications of the last 20 years with a pubmed search using the following key words: impacted third molar, swelling third molar, wisdom tooth, edema jaw, corticosteroids and extraction third molar, antibiotic prophylaxis and tooth extraction. Attention has often been focused on corticosteroid therapy administered by diverse routes (orally, IV, IM, topically) and at different time schedules (before or after surgery or both). This investigation revealed how the use of different molecules and dosages makes the obtained results hardly comparable. Similar conclusions can be drawn from studies aimed at evaluating the efficacy of antibiotic therapy administered either before or after surgery. A complete review has also to take into account different surgical strategies used including various flaps, no traumatic osteothomy, and primary or secondary closure. The use of pharmacological therapy and application of an ice pack is critical in the postoperative period and has always provided positive results. However, even if it is difficult to come to definite conclusions, due to the variability of the design of studies analyzed, the postoperative discomfort identified with edema, pain and trismus following wisdom tooth removal is influenced by various factors such as the difficulty of the surgical procedure involved, age and gender of the patient, and experience of the surgeon. The pharmacological therapy when performed with corticosteroids seems to improve control of the postoperative swelling related with this kind of surgeries. PMID:22135686

  1. Pediatric Sialadenosis Due to Valproic Acid.

    PubMed

    Derin, Hatice; Derin, Serhan; Oltulu, Pembe; Özbek, Orhan; Çaksen, Hüseyin

    2016-12-23

    Sialadenosis is a rare entity characterized by bilateral diffuse, painless swelling of the parotid glands. Its etiology is not clear; however, it may occur due to adverse effects of some drugs. To our knowledge, sialadenosis due to valproic acid has not been reported in the literature up to date in any child. In this article, the authors presented a child who developed sialadenosis due to valproic acid, and improved after stopping use of the drug.

  2. In aging, the vulnerability of rat brain mitochondria is enhanced due to reduced level of 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNP) and subsequently increased permeability transition in brain mitochondria in old animals.

    PubMed

    Krestinina, Olga; Azarashvili, Tamara; Baburina, Yulia; Galvita, Anastasia; Grachev, Dmitry; Stricker, Rolf; Reiser, Georg

    2015-01-01

    Aging is accompanied by progressive dysfunction of mitochondria associated with a continuous decrease of their capacity to produce ATP. Mitochondria isolated from brain of aged animals show an increased mitochondrial permeability transition pore (mPTP) opening. We recently detected new regulators of mPTP function in brain mitochondria, the enzyme 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and its substrates 2', 3'-cAMP and 2', 3'-cNADP, and the neuronal protein p42(IP4). Here, we compared parameters of mPTP opening in non-synaptic brain mitochondria isolated from young and old rats. In mitochondria from old rats (>18 months), mPTP opening occurred at a lower threshold of Ca(2+) concentration than in mitochondria from young rats (<3 months). mPTP opening in mitochondria from old rats was accelerated by 2', 3'-cAMP, which further lowered the threshold Ca(2+) concentration. In non-synaptic mitochondria from old rats, the CNP level was decreased by 34%. Lowering of the CNP level in non-synaptic mitochondria with aging was accompanied by decreased levels of voltage-dependent anion channel (VDAC; by 69%) and of p42(IP4) (by 59%). Thus, reduced levels of CNP in mitochondria could lead to a rise in the concentration of the mPTP promoter 2', 3'-cAMP. The level of CNP and p42(IP4) and, probably VDAC, might be essential for myelination and electrical activity of axons. We propose that in aging the reduction in the level of these proteins leads to mitochondrial dysfunction, in particular, to a decreased threshold Ca(2+) concentration to induce mPTP opening. This might represent initial steps of age-related mitochondrial dysfunction, resulting in myelin and axonal pathology.

  3. 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

  4. Near-infrared spectroscopy (NIRS)-based eyes-closed brain-computer interface (BCI) using prefrontal cortex activation due to mental arithmetic

    PubMed Central

    Shin, Jaeyoung; Müller, Klaus-R; Hwang, Han-Jeong

    2016-01-01

    We propose a near-infrared spectroscopy (NIRS)-based brain-computer interface (BCI) that can be operated in eyes-closed (EC) state. To evaluate the feasibility of NIRS-based EC BCIs, we compared the performance of an eye-open (EO) BCI paradigm and an EC BCI paradigm with respect to hemodynamic response and classification accuracy. To this end, subjects performed either mental arithmetic or imagined vocalization of the English alphabet as a baseline task with very low cognitive loading. The performances of two linear classifiers were compared; resulting in an advantage of shrinkage linear discriminant analysis (LDA). The classification accuracy of EC paradigm (75.6 ± 7.3%) was observed to be lower than that of EO paradigm (77.0 ± 9.2%), which was statistically insignificant (p = 0.5698). Subjects reported they felt it more comfortable (p = 0.057) and easier (p < 0.05) to perform the EC BCI tasks. The different task difficulty may become a cause of the slightly lower classification accuracy of EC data. From the analysis results, we could confirm the feasibility of NIRS-based EC BCIs, which can be a BCI option that may ultimately be of use for patients who cannot keep their eyes open consistently. PMID:27824089

  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. Uncommon inflammatory swelling of the lips: orofacial granulomatosis.

    PubMed

    Hafiz, Abdul; Mufeed, Abdulla; Kandasamy, Gopinath; Krishnapillai, Rekha

    2016-01-12

    Orofacial granulomatosis (OFG) is an unusual condition associated with permanent or recurrent swelling of orofacial tissues together with oral mucosal ulceration and a variety of orofacial characteristics. The chronic inflammation inherent to OFG often displays granulomas in the subepithelial stroma. We present a case of OFG and its management. The patient responded to intralesional injections of corticosteroids.

  7. 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...

  8. 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)

  9. 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.

  10. Absorption and swelling characteristics of silver (I) antimicrobial wound dressings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An important characteristic of moist wound dressings is their ability to swell and absorb exudates from the wound, while maintaining a moist atmosphere at the wound site. At the Southern Regional Research Center (SRRC), we have previously developed antimicrobial silver-sodium-carboxymethylated (CM)-...

  11. Sternocostoclavicular Joint Swelling; Diagnosis of a Neglected Entity

    PubMed Central

    Sharma, Deep; Dhiman, Pooja; Menon, Jagdish; Krishna, Komuravalli Varun

    2015-01-01

    Background: Sternocostoclavicular joint (SCCJ) swelling is an underdiagnosed, albeit important entity in clinical practice. The present study was conducted in order to identify the incidence and common causes of this entity. Methods: Patients presenting to the Orthopaedic Clinic with a swelling of the sternocostoclavicular joint, during the study period of two years were included, and detailed history was obtained from the patient. Baseline investigations (total and differential leukocyte count, ESR, CRP, X-ray and CT) wereperformed. Magnetic resonance imaging,FNAC or joint aspiration was performed whenever clinically or radiologically indicated. Results: A total of 21 patients were enrolled into the study for a duration of 2 years. Patients mainly presented with both pain and swelling of the SCCJ with predominant right sided involvement. Osteoarthritis was the most frequent diagnosis followed by infections, primary bone/cartilage tumor, and metastasis. Conclusions: Although most of the patients with SCCJ swelling have a benign etiology, it is not wise to dismiss thisswelling as degenerative changes. Serious conditions like septic arthritis or neoplasia, may masquerade with similar presentations such as osteoarthritis. It would be therefore imperative to rule out all of these potentially life threatening conditions using thorough clinic-radiological workups. PMID:26110174

  12. Bulk Etch Rate and Swell Rate of CR-39

    NASA Astrophysics Data System (ADS)

    Clarkson, David; Ume, Rubab; Sheets, Rebecca; Regan, Sean; Sangster, Craig; Padalino, Stephen; McLean, James

    2016-10-01

    The use of CR-39 plastic as a Solid State Nuclear Track Detector is an effective technique for obtaining data in high-energy particle experiments including inertial confinement fusion. To reveal particle tracks after irradiation, CR-39 is chemically etched in NaOH at 80°C, producing micron-scale signal pits at the nuclear track sites. The development of these pits depends on both the bulk etch rate and the faster etch rate along the track, and is complicated by swelling as water is absorbed. Contrary to common etching models, we find the bulk etch rate to be depth dependent within 15 μ m of the surface, as revealed by swelling TASTRACK CR-39 pieces to their maximum capacity prior to etching. The bulk etch rate was measured using the standard mass method as well as the fission fragment track diameter method. Combining models of swelling and etching rates predicts the progress of bulk etching during a standard etch, without pre-swelling. This result has implications for the understanding the chemistry of the etch process, as well as the outcome of CR-39 surface preparation methods. Funded in part by a LLE contract through the DOE.

  13. Hydrogel films and coatings by swelling-induced gelation.

    PubMed

    Moreau, David; Chauvet, Caroline; Etienne, François; Rannou, François P; Corté, Laurent

    2016-11-22

    Hydrogel films used as membranes or coatings are essential components of devices interfaced with biological systems. Their design is greatly challenged by the need to find mild synthesis and processing conditions that preserve their biocompatibility and the integrity of encapsulated compounds. Here, we report an approach to produce hydrogel films spontaneously in aqueous polymer solutions. This method uses the solvent depletion created at the surface of swelling polymer substrates to induce the gelation of a thin layer of polymer solution. Using a biocompatible polymer that self-assembles at high concentration [poly(vinyl alcohol)], hydrogel films were produced within minutes to hours with thicknesses ranging from tens to hundreds of micrometers. A simple model and numerical simulations of mass transport during swelling capture the experiments and predict how film growth depends on the solution composition, substrate geometry, and swelling properties. The versatility of the approach was verified with a variety of swelling substrates and hydrogel-forming solutions. We also demonstrate the potential of this technique by incorporating other solutes such as inorganic particles to fabricate ceramic-hydrogel coatings for bone anchoring and cells to fabricate cell-laden membranes for cell culture or tissue engineering.

  14. 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.

  15. Irradiated PVAl membrane swelled with chitosan solution as dermal equivalent

    NASA Astrophysics Data System (ADS)

    Rodas, A. C. D.; Ohnuki, T.; Mathor, M. B.; Lugao, A. B.

    2005-07-01

    Synthetic membranes as dermal equivalent can be applied at in vitro studies for developing new transdermal drugs or cosmetics. These membranes could be composed to mimic the dermis and seed cultivated keratinocytes as epidermal layer on it. The endothelial cells ingrowth to promote neovascularization and fibroblasts ingrowth to promote the substitution of this scaffold by natural components of the dermis. As, they can mimic the scaffold function of dermis; the membranes with biological interaction could be used for in vivo studies as dermal equivalent. For this application, poly(vinyl alcohol) (PVAl) membranes crosslinked by gamma radiation were swelled with chitosan solution. PVAl do not interact with the organism when implanted and is intended to mimic the mechanical characteristics of the dermal scaffold. The chitosan as a biocompatible biosynthetic polysaccharide were incorporated into PVAl membranes to improve the organism response. Degradation of chitosan by the organism occurs preferably by hydrolysis or enzymatic action, for example, by lysozyme. For this purpose the swelling kinetic of PVAl membranes with chitosan solution were performed and it was verified their degradation in vitro. The results showed that the swelling equilibrium of the PVAl membranes with chitosan membranes was reached in 120 h with average swelling of 1730%. After swelling, PVAl and chitosan/PVAl membranes were dried and immersed in phosphate buffer solution pH 5.7 and pH 7.4, with and without lysozyme, as those pH values are the specific physiologic pH for external skin and the general physiological pH for the organism, respectively. It was verified that the pure PVAl membrane did not showed change in their mass during 14 days. PVAl membranes swelled with chitosan solution showed mass decrease from 1 to 14 days inside these solutions. The highest mass decrease was verified at pH 5.7 in phosphate buffer solution without lysozyme. The smallest mass decrease was verified at pH 7.4 in

  16. Poly(Vinyl Alcohol)/Poly(Acrylic Acid) Hydrogel in a dc Electric Field: Swelling, Shape Change, and Actuation Characteristics

    PubMed Central

    2014-01-01

    Poly(vinyl alcohol) (PVA)/Poly(acrylic acid) (PAA) hydrogel can be utilized as a biomimetic actuator and coating material for tissue-implant interface, when employing an electrical stimulus. The swelling, shape change, and actuation characteristics of PVA/PAA hydrogel in a range of dc electrical fields were determined to find the optimal electric field for the hydrogel application as biomimetic actuator and coating materials. The hydrogel samples were prepared by dissolving PVA and PAA in deionized water at 4 wt% and mixed together at 1:1 ratio. Two custom made experimental setups were fabricated; one used for the measurement of swelling ratio of the hydrogels; and the other used for the shape changes or actuation characteristics of the hydrogels. Swelling experiments show increased swelling ratios of the hydrogel due to 10 V, 20 V, and 30 V electric fields. The rate of increment of the swelling ratio of hydrogel samples under 10V was higher compare to those samples under 20 V and 30 V. The width and height changes of rectangular shapes and maximum deflection along the length of hydrogel sample due to a range of electric fields (0-30V) were measured using an optical microscope. Incremental shape change up to a specific threshold value (around 10V) was observed due to electric stimulus. Electrostatic actuation pressure of hydrogel samples under 10V was higher compare to those samples under 20 V and 30 V. These results suggested that optimal performance of PVA/PAA hydrogel can be achieved around 10V. PMID:25478321

  17. Swelling of Erectile Nasal Tissue Induced by Human Sexual Pheromone.

    PubMed

    Mazzatenta, Andrea; De Luca, C; Di Tano, A; Cacchio, M; Di Giulio, C; Pokorski, Mieczyslaw

    2016-01-01

    Most chemically mediated sexual communication in humans remains uncharacterized. Yet the study of sexual communication is decisive for understanding sexual behavior and evolutive mechanisms in our species. Here we provide the evidence to consider 4,16-androstadien-3-one (AND) as a man's sexual pheromone. Our experiment provides support for the physiological effect of AND on nasal airway resistance (Rna) in women, as assessed by anterior rhinomanometry. We found that AND administration increased the area of turbinate during the ovulatory phase, resulting in an increase of Rna. Thus, we discovered that minute amounts of AND, acting through neuroendocrine brain control, regulate Rna and consequently affect the sexual physiology and behavior. Fascinatingly, this finding provides the evidence of the preservation of chemosexual communication in humans, which it has been largely neglected due to its unconscious perception and concealed nature. Therefore, chemical communication is a plesiomorphic evolutive phenomenon in humans.

  18. Crossing Swell and Origins: Global View from ASAR Wave Mode Fireworks

    NASA Astrophysics Data System (ADS)

    Wang, He; Mouche, Alexis; Husson, Romain; Chapron, Bertrand; Yang, Jingsong

    2016-08-01

    Crossing swell, is a complicated sea state characterized by the co-existence of swell systems generating from different swell origins. Although many investigations have focused on the global swell climatology, our understanding of global statistical distribution for the crossing swell is still limited. In this paper, we present a global view of crossing swell using 10-years Synthetic Aperture Radar (SAR) derived directional swell spectra from Envisat ASAR in Wave Mode from 2003 to 2011. In contrast to analyze the directly but occasionally SAR captured sea state of crossing swell, we employ an approach of propagating observed swell taking advantage of the internal consistency of swells. Results reveal three dominated crossing swell areas termed "crossing swell pools", in Pacific, Atlantic and Indian Oceans. The pool in Atlantic Ocean shows a relative stable behaviour for all seasons, in contrast to the one in Indian Ocean with seasonal occurrence and the one in Pacific Ocean shrinking during boreal summer. The sources of the crossing swell are also inferred from ASAR wave mode data, and its global distribution analysis results indicate good agreement with the seasonal variation of crossing swell pools.

  19. Tuning Smart Microgel Swelling and Responsive Behavior through Strong and Weak Polyelectrolyte Pair Assembly

    PubMed Central

    Costa, Eunice; Lloyd, Margaret M.; Chopko, Caroline; Aguiar-Ricardo, Ana; Hammond, Paula T.

    2012-01-01

    The layer-by-layer (LbL) assembly of polyelectrolyte pairs on temperature and pH-sensitive cross-linked poly(N-isopropylacrylamide)-co-(methacrylic acid), poly(NIPAAm-co-MAA), microgels enabled a fine tuning of the gel swelling and responsive behavior according to the mobility of the assembled polyelectrolyte (PE) pair and the composition of the outermost layer. Microbeads with well-defined morphology were initially prepared by synthesis in supercritical carbon dioxide. Upon LbL assembly of polyelectrolytes, interactions between the multilayers and the soft porous microgel led to differences in swelling and thermoresponsive behavior. For the weak PE pairs, namely poly(L-lysine) / poly(L-glutamic acid) and poly(allylamine hydrochloride) / poly(acrylic acid), polycation-terminated microgels were less swollen and more thermoresponsive than native microgel; while polyanion-terminated microgels were more swollen and not significantly responsive to temperature, in a quasi-reversible process with consecutive PE assembly. For the strong PE pair, poly(diallyldimethylammonium chloride) / poly(sodium styrene sulfonate), the differences among polycation and polyanion-terminated microgels are not sustained after the first PE bilayer due to extensive ionic cross-linking between the polyelectrolytes. The tendencies across the explored systems became less noteworthy in solutions with larger ionic strength due to overall charge shielding of the polyelectrolytes and microgel. ATR FT-IR studies correlated the swelling and responsive behavior after LbL assembly on the microgels with the extent of H-bonding and alternating charge distribution within the gel. Thus, the proposed LbL strategy may be a simple and flexible way to engineer smart microgels in terms of size, surface chemistry, overall charge and permeability. PMID:22676290

  20. Swellings of the angle of the mandible in 32 horses (1997-2011).

    PubMed

    Dixon, P M; Loh, N; Barakzai, S Z

    2014-01-01

    Disorders of the horizontal ramus (body) of the equine mandible are well reported, but there is minimal documentation of disorders of the angle of mandible. A retrospective examination of the records of Edinburgh University Equine Hospital (1997-2011) showed that 32 horses were referred due to swellings of the angle of the mandible. The aetiology of these swellings was identified in just 13/32 cases (41%) including fractures (n=2), traumatic, localised periosteal/cortical lesions (n=4), traumatic soft tissue lesions (n=2), neoplasia (n=3), and inflammation of the adjacent salivary gland (n=1) and masseter muscle (n=1). The remaining 19 (59%) cases without a definitive diagnosis showed two patterns of lesions. Twelve cases had localised periosteal/cortical lesions of the ventral aspect of the angle of mandible that were most likely traumatic in origin. The remaining seven undiagnosed cases without mandibular bony changes all had sinus tracts/chronic soft tissue infections on the medial aspect of the angle of the mandible which were believed to be caused by a draining retro-pharyngeal lesion in five cases. Surgical excision of abnormal soft tissues (if present) and bone curettage was the most successful treatment. It was concluded that the aetiology of swellings of the angle of the equine mandible are often obscure; most appear to be traumatic in origin, yet horses seldom develop gross fractures at this site due to the support of the dense surrounding musculo-tendinous structures. A smaller proportion are caused by draining retropharyngeal lesions that respond poorly to medical therapy, but respond well to surgical treatment.

  1. SAR imagery of ocean-wave swell traveling in an arbitrary direction

    NASA Technical Reports Server (NTRS)

    Rufenach, C. L.; Shuchman, R. A.; Lyzenga, D. R.

    1984-01-01

    The intensity wave like patterns observed in Synthetic Aperture Radar (SAR) are known to be caused by two mechanisms: the microwave radar cross sectional amplitude modulation due to tilt and hydrodynamic interaction of the long ocean waves, and intensity modulation due to the motion of the long ocean waves. Two dimensional closed form expressions of intensity wave patterns based on ocean wave swell are developed. They illustrate the relative importance of the amplitude and motion modulations; they also show that velocity bunching and a distortion due to the phase velocity of the ocean wave field are independent of the focus adjustment, provided that the second order temporal effects are neglected. Second order effects are small only over a limited range of ocean/radar parameters.

  2. Developing a swell-dependent surface roughness length for atmosphere-wave-ocean coupled models

    NASA Astrophysics Data System (ADS)

    Rutgersson, Anna; Wu, Lichuan

    2014-05-01

    When modelling the atmosphere and the ocean it is of crucial importance to correctly describe the boundary conditions. The atmospheric-ocean boundary is an important source of turbulence and there is a significant exchange of momentum, heat and moisture. The marine atmospheric boundary layer (MABL) has a considerable impact on global climate atmospheric models as 70 % of the global surface is covered with water. For regional scale models with higher resolution correctly described coupling of spheres is of particular importance in coastal regions due to the greater variability of several parameters. Surface waves can be divided into growing sea (young sea) and decaying sea (swell) with very different impact on the atmosphere. The situation with decaying sea and low wave height has in several experimental investigations been shown to give significantly lower friction at the surface as well as altered wind profiles and atmospheric turbulence. New results using data taken outside Hawaii shows that for high swell waves, wind profiles and turbulence properties are altered similarly as for low swell waves, but the surface friction is significantly enhanced (Rutgersson et al, 2010; Högström et al., 2009; 2012; Smedman et al., 2009). We use a three component regional climate modelling system to investigate the changed surface roughness description. The model covers northern Europe and model components include the atmosphere model RCA (Rossby Centre Climate model), WAM wave model and NEMO ocean model for the Baltic and North Seas. Presently the coupling is focused on introducing wave impact on the atmosphere. Sea surface roughness length is improved to take the variable swell properties into account. Roughness length is expressed in terms of the wave age and significant swell wave height. The impact of improved roughness length on surface fluxes and wind field is investigated as well as the impact on secondary parameters. Högström, U., A. Smedman, E. Sahleé, W

  3. Constraints on Pacific midplate swells from global depth-age and heat flow-age models

    NASA Astrophysics Data System (ADS)

    Stein, Carol A.; Stein, Seth

    provide no evidence for the Darwin Rise being thermally different at present from lithosphere of the same age elsewhere. The situation for the Superswell is similar to that for Hawaii, in that the heat flow data are consistent with those for unperturbed lithosphere, despite the shallow bathymetry. Flexural data for the Superswell indicate that the lithosphere was anomalously weak at the time of seamount loading. This also appears to have been the case for the Darwin Rise, but not for the Hawaiian or other swells. Although the weakness has been interpreted as due to elevated temperatures in the lithosphere, the requited high temperatures should give rise to heat flow much higher than observed. Hence the flexural strength anomaly with respect to Hawaii and other swells suggests that the lithosphere for the Superswell and Darwin Rise has been mechanically weakened by the cumulative action of multiple hot spots.

  4. 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.

  5. Persistent eyelid swelling in a patient with rosacea.

    PubMed

    Morales-Burgos, Adisbeth; Alvarez Del Manzano, Gilberto; Sánchez, Jorge L; Cruz, Carmen L

    2009-03-01

    Persistent facial swelling may occur as a rare complication of rosacea. This finding has been referred to as lymphedematous rosacea, Morbihan's disease or persistent solid facial edema. A literature review for cases of lymphedematous rosacea revealed that the chronic inflammatory process that accompanies the disease contributes to an increase in the permeability of blood vessels. With time, the lymphatic drainage system becomes permanently impaired, leading to fluid accumulation in the affected skin. Herein, we report the case of a 58-year-old female with history of rosacea who developed bilateral periorbital swelling with associated erythema of the conjunctiva (ocular rosacea) over a 4 month period that only responded to oral corticosteroids. Biopsy revealed changes of lymphedematous rosacea.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. The trumpet player with a swelling in the neck

    PubMed Central

    Edmiston, Rachel; Hariri, Ahmad; Karagama, Yakubu

    2015-01-01

    Bilateral neck swelling in patients following valsalva manouveres could lead to a diagnosis of either a pharyngocele or laryngocele. Distinguishing between them can be complicated but is vital given the possibility for an acute airway in patients with laryngoceles. A 20-year-old trumpet player presents with a 5-year history of neck swelling. Clinical suspicion is that of a pharyngocele but imaging introduces some confusion with the diagnosis. Both pharyngoceles and laryngoceles can occur as a result of prolonged positive pressure. Accurate assessment with fibreoptic examination and imaging is needed to confirm the diagnosis. Pharyngoceles are often misdiagnosed as laryngoceles. Though treatment is similar between the two patient groups it is vital that a distinction is made to enable careful observation of the airway in patients with laryngoceles. PMID:25795752

  11. 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.

  12. SWELLING OF ERYTHROCYTES IN SOLUTIONS OF AMMONIUM SALTS

    PubMed Central

    Schiödt, E.

    1933-01-01

    Two rather simple equations have been derived, which make it possible to express in a single number the result of a series of determinations of the volume of erythrocytes swelling in solutions of ammonium salts. In all experiments made with several combinations of different concentrations of permeating and non-permeating salts, the curves calculated from the equations have covered the points found by experiment. PMID:19872754

  13. 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.

  14. 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.

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

    PubMed

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

    2015-06-05

    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.

  16. Unilateral optic disc swelling in a fighter pilot.

    PubMed

    Pokroy, Russell; Barenboim, Erez; Carter, Dan; Assa, Amit; Alhalel, Amir

    2009-10-01

    Optic disc swelling occurs when there is an obstruction to axonal transport at the level of the lamina cribrosa. This may result from compression, ischemia, inflammation, or metabolic and toxic etiologies. Some of these etiologies may be life threatening and others may be self-limited. Thus, differentiating the different etiologies is important, albeit often difficult. We present a case of a 25-yr-old high-performance fighter aviator who presented with unilateral optic disc swelling 2 d after an F-16 flight, in which decompression was suspected. Visual acuity of the affected eye was decreased to 20/25, with enlarged blind spot and shallow arcuate scotomata on visual field testing. Pupil function, brightness intensity, and color vision were normal. Marked swelling of the entire optic disc, retinal flame-shaped hemorrhages, and engorgement of the retinal veins were seen. Since decompression sickness with nitrogen bubbles obstructing the optic nerve head vasculature was suspected, he was treated with hyperbaric oxygen. He rapidly improved, recovering full vision function within 6 d. No concurrent disease was found on extensive investigation. He returned to high-performance aviation 3 mo after onset of symptoms. No recurrence was seen during 3 yr of follow-up.

  17. Bioceramic microneedles with flexible and self-swelling substrate.

    PubMed

    Cai, Bing; Xia, Wei; Bredenberg, Susanne; Li, Hao; Engqvist, Håkan

    2015-08-01

    To reduce the effort required to penetrate the skin and optimize drug release profiles, bioceramic microneedle arrays with higher-aspect-ratio needles and a flexible and self-swelling substrate have been developed. Swelling of the substrate can assist in separating it from the needles and leave them in the skin as a drug depot. The preparation procedures for this bioceramic microneedle are described in the paper. Clonidine hydrochloride, the model drug, was released in a controlled manner by the microneedle device in vitro. Results showed that the microneedle array with a flexible and self-swelling substrate released the drug content faster than the array with a rigid substrate. Disintegration of the needle material and diffusion of the drug molecules are believed as the main control mechanisms of the drug release from these microneedle arrays. Ex vivo skin penetration showed that they can effectively penetrate the stratum corneum without an extra device. This work represents a progression in the improvement of bioceramic microneedles for transdermal drug delivery.

  18. Quantifying Shrink Swell Capacity of Soil Using Soil Moisture Isotherms

    NASA Astrophysics Data System (ADS)

    Rivera, L. D.; Cobos, D. R.; Campbell, C. S.; Morgan, C.

    2013-12-01

    Vertisols, soils instinctively known for their expansive clays that cause them to have a high shrink swell potential, cover 2.4% of the earths ice-free land. In the United States these expansive soils can cause upwards of 6 billion in damages to pavements, foundations, and utility lines annually (Brady & Weil, 2010). Because of this, it is especially important that a soils ability to shrink and swell is well characterized when making engineering decisions. One traditional method for measuring a soil's expansive potential, the Coefficient of Linear Extensibility (COLE), can take weeks to months to complete (Grossman et al., 1968; Schafer and Singer, 1976b). Use of soil moisture isotherms, or the Soil Moisture Characteristic Curve (SMCC), in recent research has shown that the slope of the SMCC is related to a soils swelling potential (McKeen, 1992). The goal of this research is to evaluate the robustness of the relationship between the SMCC and COLE for a set of well-characterized test soils with COLE ranging from 0 to 0.176. If expansive potential can be reliably predicted from the SMCC, then data from recently developed automatic soil moisture isotherm generators could be used to characterize expansive potential with a fraction of the time and effort necessary for traditional techniques.

  19. Water influx and cell swelling after nanosecond electropermeabilization.

    PubMed

    Romeo, Stefania; Wu, Yu-Hsuan; Levine, Zachary A; Gundersen, Martin A; Vernier, P Thomas

    2013-08-01

    Pulsed electric fields are used to permeabilize cell membranes in biotechnology and the clinic. Although molecular and continuum models provide compelling representations of the mechanisms underlying this phenomenon, a clear structural link between the biomolecular transformations displayed in molecular dynamics (MD) simulations and the micro- and macroscale cellular responses observed in the laboratory has not been established. In this paper, plasma membrane electropermeabilization is characterized by exposing Jurkat T lymphoblasts to pulsed electric fields less than 10ns long (including single pulse exposures), and by monitoring the resulting osmotically driven cell swelling as a function of pulse number and pulse repetition rate. In this way, we reduce the complexity of the experimental system and lay a foundation for gauging the correspondence between measured and simulated values for water and ion transport through electropermeabilized membranes. We find that a single 10MV/m pulse of 5ns duration produces measurable swelling of Jurkat T lymphoblasts in growth medium, and we estimate from the swelling kinetics the ion and water flux that follows the electropermeabilization of the membrane. From these observations we set boundaries on the net conductance of the permeabilized membrane, and we show how this is consistent with model predictions for the conductance and areal density of nanoelectropulse-induced lipid nanopores.

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

    PubMed

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

    2005-02-01

    1. Herein we study the effects of the mitochondrial complex II inhibitor malonate on its primary target, the mitochondrion. 2. 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. 3. 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. 4. 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. 5. When GSH concentrations were lowered with buthionine sulphoximine, cytoprotection afforded by Bcl-xL overexpression was not evident anymore. 6. 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.

  1. [Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) associated with swelling in the brainstem: a case report].

    PubMed

    Tani, Hiroki; Nakajima, Hideto; Yamane, Kazushi; Ohnishi, Hiroyuki; Kimura, Fumiharu; Hanafusa, Toshiaki

    2014-01-01

    Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare central nervous system inflammatory disease characterized by the punctate gadolinium enhancement peppering the pons and the cerebellar peduncles as neuroimaging. We report the case of a 66-year-old woman who presented with CLIPPERS associated with swelling in the brainstem. She was hospitalized because of gait ataxia and consciousness disturbance. MRI of the brain showed FLAIR hyperintense lesions in the pons, cerebellar peduncles, cerebellum and the subcortical white matter lesion in the right occipital lobe with significant swelling in the brainstem. Diffusion-weighted MRI did not show an abnormal signal, indicating vasogenic edema. Post-contrast T1-weighted MRI showed enhanced area in the right occipital lobe and panctate gadolinium enhancement peppering brainstem. Treatment with steroids led to rapid improvement. However, she showed exacerbation of clinical and radiological findings during the tapering schedule of steroid. The biopsy from the occipital lobe revealed intense perivascular and parenchymal lymphocytic infiltrates composed of primarily T cells, B cells and macrophages. The patient was diagnosed with CLIPPERS, and treatment with increased dose of corticosteroid induced a clinical improvement. Previous reports well described a characteristic MRI finding of punctate enhancement peppering the pons. In addition, the pons and cerebellar peduncles swelling can occur in this disorder.

  2. 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.

  3. Creep and Sliding in Clay Slopes: Mutual Effects of Interlayer Swelling and Ice Jacking.

    DTIC Science & Technology

    1983-08-24

    project, swelling and freezing, have been treated as well. The extent of swell heave of the montmorillonite clay under investigation depends on the...the amount of clay size particles: up to 70% and the amount of montmorillonite : up to 35%. 1.2. Grain Size Distribution Twelve hydrometer tests were...in physical conditions and exhibit swelling again upon subsequent wetting. Another important swelling parameter is the montmorillonite content, that

  4. Sexual swellings in wild white-handed gibbon females (Hylobates lar) indicate the probability of ovulation.

    PubMed

    Barelli, Claudia; Heistermann, Michael; Boesch, Christophe; Reichard, Ulrich H

    2007-02-01

    Conspicuous sexual swellings in the females of some primate species have been a focus of scientific interest since Darwin first wrote about them in 1871. To understand these visual signals, research focused on exaggerated sexual swellings of Old World primates. However, some primate species develop much smaller sexual swellings and it is as yet unclear if these smaller swellings can serve similar functions as those proposed for exaggerated swellings, i.e. advertising fertility to attract mates. We studied the temporal patterns of sexual swellings, timing of ovulation and female reproductive status in wild white-handed gibbons (Hylobates lar) at Khao Yai National Park, Thailand, where this species has a variable social organization. We established fecal progestogen profiles in fifteen cycles of eight cycling females and, to detect swellings outside the menstrual cycle, five pregnant and six lactating females. In 80% of menstrual cycles, ovulation and maximum swelling phase (duration: Ø 9.3 days; 42.8% of cycle length), overlapped tightly. The probability of ovulation peaked on day 3 of the maximum swelling period. Nevertheless, the temporal relationship between maximum swelling and probability of ovulation varied from day -1 to day 13 of the swelling period and three times ovulations fell outside the maximum swelling phase. The different swellings phases occurred in similar proportions in cycling and pregnant, but not lactating females, which were rarely swollen. Despite their smaller size, gibbons' sexual swellings probably serve functions similar to those suggested for exaggerated swellings by the graded-signal hypothesis, which predicts that sexual swellings indicate the probability of ovulation, without allowing males to pinpoint its exact time.

  5. 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

    2015-07-08

    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.

  6. Neutron Diffraction of Aqueous Tetramethylammonium Chloride (TMA) Solutions and TMA Intercalated Swelling Clays Under Burial Conditions

    NASA Astrophysics Data System (ADS)

    Patel, R.; Howard, C. A.; Greenwell, C.; Youngs, T.; Soper, A. K.; Skipper, N. T.

    2014-12-01

    There is a need for the improvement and optimisation of clay swelling inhibitors for the enhancement of oil and gas exploration. The hydration region of both ions and the possibility of ion pairing in 1 molar aqueous solution of clay swelling inhibitor, tetramethylammonium chloride (TMACl), in D2O, under elevated hydrostatic-pressures and temperatures has been determined with unprecedented detail using a combination of neutron diffraction and small-angle scattering in conjunction with hydrogen/deuterium isotopic labeling. The O-H correlation function (H-bonds) for the water in the 1.0M solution is measured and compared with that for pure D2O. Also investigated is the effect of burial conditions on the d-spacing of TMA-intercalated vermiculite. Contrary to expectations, no aggregation of TMA ions due to hydrophobic interactions is observed, nor are any ionic pairs of TMA+ and Cl- at these burial conditions. The data revealed a more ordered water-water structure with the addition of TMACl from bulk D2O. There is no change in the hydration structure measured at the applied elevated conditions. This is in remarkable contrast to pure water at the same conditions which is well known to be compressible. The dry d-spacing of the TMA-exchanged Eucatex vermiculite is measured at 13.66 Å which increases to 14.03 Å with the addition of D2O. Beyond this, there is no change in d-spacing with increasing pressure and temperature indicating the strength of the TMA ions binding to the clay interlayers and therefore its performance as a clay-swelling inhibitor.

  7. 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

  8. Guest-responsive reversible swelling and enhanced fluorescence in a super-absorbent, dynamic microporous polymer.

    PubMed

    Rao, K Venkata; Mohapatra, Sudip; Maji, Tapas Kumar; George, Subi J

    2012-04-10

    A swell idea! The guest-responsive reversible swelling and fluorescence enhancement of a dynamic, microporous polymer network is presented. Guest-induced breathing of hydrophobic pores imparts multi-functional properties, such as super-absorbency, phase-selective swelling of oil from water and encapsulation of C(60) (see figure), to this soft micro-porous organic polymer.

  9. 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

  10. Partial interruption of axonal transport due to microtubule breakage accounts for the formation of periodic varicosities after traumatic axonal injury.

    PubMed

    Tang-Schomer, Min D; Johnson, Victoria E; Baas, Peter W; Stewart, William; Smith, Douglas H

    2012-01-01

    Due to their viscoelastic nature, white matter axons are susceptible to damage by high strain rates produced during traumatic brain injury (TBI). Indeed, diffuse axonal injury (DAI) is one of the most common features of TBI, characterized by the hallmark pathological profiles of axonal bulbs at disconnected terminal ends of axons and periodic swellings along axons, known as "varicosities." Although transport interruption underlies axonal bulb formation, it is unclear how varicosities arise, with multiple sites accumulating transported materials along one axon. Recently, axonal microtubules have been found to physically break during dynamic stretch injury of cortical axons in vitro. Here, the same in vitro model was used in parallel with histopathological analyses of human brains acquired acutely following TBI to examine the potential role of mechanical microtubule damage in varicosity formation post-trauma. Transmission electron microscopy (TEM) following in vitro stretch injury revealed periodic breaks of individual microtubules along axons that regionally corresponded with undulations in axon morphology. However, typically less than a third of microtubules were broken in any region of an axon. Within hours, these sites of microtubule breaks evolved into periodic swellings. This suggests axonal transport may be halted along one broken microtubule, yet can proceed through the same region via other intact microtubules. Similar axonal undulations and varicosities were observed following TBI in humans, suggesting primary microtubule failure may also be a feature of DAI. These data indicate a novel mechanism of mechanical microtubule damage leading to partial transport interruption and varicosity formation in traumatic axonal injury.

  11. On sorption and swelling of CO2 in clays

    DOE PAGES

    Busch, A.; Bertier, P.; Gensterblum, Y.; ...

    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

  12. Generalized Rate Theory for Void and Bubble Swelling and its Application to Plutonium Metal Alloys

    SciTech Connect

    Allen, P. G.; Wolfer, W. G.

    2015-10-16

    In the classical rate theory for void swelling, vacancies and self-interstitials are produced by radiation in equal numbers, and in addition, thermal vacancies are also generated at the sinks, primarily at edge dislocations, at voids, and at grain boundaries. In contrast, due to the high formation energy of self-interstitials for normal metals and alloys, their thermal generation is negligible, as pointed out by Bullough and Perrin [1]. However, recent DFT calculations of the formation energy of self-interstitial atoms in bcc metals [2,3] have revealed that the sum of formation and migration energies for self-interstitials atoms (SIA) is of the same order of magnitude as for vacancies. This is illustrated in Fig. 1 that shows the ratio of the activation energies for thermal generation of SIA and vacancies. For fcc metals, this ratio is around three, but for bcc metals it is around 1.5. Reviewing theoretical predictions of point defect properties in δ-Pu [4], this ratio could possibly be less than one. As a result, thermal generation of SIA in bcc metals and in plutonium must be taken into considerations when modeling the growth of voids and of helium bubbles, and the classical rate theory (CRT) for void and bubble swelling must be extended to a generalized rate theory (GRT).

  13. Teaching ocean wave forecasting using computer-generated visualization and animation—Part 2: swell forecasting

    NASA Astrophysics Data System (ADS)

    Whitford, Dennis J.

    2002-05-01

    This paper, the second of a two-part series, introduces undergraduate students to ocean wave forecasting using interactive computer-generated visualization and animation. Verbal descriptions and two-dimensional illustrations are often insufficient for student comprehension. Fortunately, the introduction of computers in the geosciences provides a tool for addressing this problem. Computer-generated visualization and animation, accompanied by oral explanation, have been shown to be a pedagogical improvement to more traditional methods of instruction. Cartographic science and other disciplines using geographical information systems have been especially aggressive in pioneering the use of visualization and animation, whereas oceanography has not. This paper will focus on the teaching of ocean swell wave forecasting, often considered a difficult oceanographic topic due to the mathematics and physics required, as well as its interdependence on time and space. Several MATLAB ® software programs are described and offered to visualize and animate group speed, frequency dispersion, angular dispersion, propagation, and wave height forecasting of deep water ocean swell waves. Teachers may use these interactive visualizations and animations without requiring an extensive background in computer programming.

  14. Impact of glissile interstitial loop production in cascades on void ordering and swelling saturation under irradiation

    NASA Astrophysics Data System (ADS)

    Dubinko, V. I.

    1995-08-01

    According to the dislocation model of void ordering and swelling saturation by the present author, these phenomena arise due to the absorption by voids of perfect glissile dislocation loops produced by irradiation. The formation and glide of small interstitial loops has been also confirmed by recent molecular dynamics (MD) studies of displacement cascades. The cascade mechanism of the loop production is shown to explain an absence of visible dislocation loops in some experiments on void lattices, which is a very important argument in favor of the present theory. However, according to the MD simulations, the glide of such loops seems not to depend on the stacking fault energy of the host lattice, contrary to the predictions of the elastic continuum theory. The latter shows that high stacking energy (as in most bcc metals and in fcc Ni and Al) favors the unfaulting of small loops, which seems to be in agreement with experimentally observed void lattice formation in these metals as compared to the resistance of the low stacking energy metals (such as Cu, Ag, Au and most steels) to void lattice formation. This discrepancy between continuum theory and MD simulations shows the need for further studies of displacement cascades, in particular, in more complex systems modeling the effects of impurities on the nature of interstitial clusters. An outstanding problem is to find impurities that can facilitate the unfaulting process and, hence, void ordering and swelling saturation in those fcc metals which are currently supposed to be void lattice resistant.

  15. 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.

  16. Ultrasonic scanning in the evaluation of scrotal swellings.

    PubMed

    Lopatkin, N A; Darenkov, A F; Marinbach, A E; Ignashin, N S

    1982-01-01

    Typical ultrasonic images of normal testes, hydrocele and cysts of the epididymis, tumors and inflammatory diseases of the testis and epididymis, and injuries of the scrotal organs obtained in the study of 137 patients are presented. The method is simple, harmless and informative. Grey scale scanning was carried out using a water bath, which gives more complete data on the structure of the testis and its epididymis as compared to routine B-mode scanning. Ultrasonography is a reliable aid to the urologist in the diagnosis of scrotal swellings.

  17. Upper limb swelling following mastectomy: lymphedema or not?

    PubMed

    Armer, Jane

    2007-04-01

    Having experienced an excisional biopsy, sentinel lymph node biopsy, and mastectomy, BH is at lifetime risk of developing post-breast cancer lymphedema in the arm on the side where her breast cancer was treated. She has two additional risk factors, among those documented in the literature: history of an infection (specifically a systemic infection, significant in that it required hospitalization for intravenous antibiotics) in the postsurgery period, and a moderate increase in bilateral limb volume and weight (body mass index) over the months and years following the breast cancer diagnosis. Further, the patient-reported transient hand swelling on the affected side and gradual weight increase are cues indicating a need for patient vigilance and careful monitoring by the health-care team. Preventing future infections, managing weight at an optimal level, and preventing trauma or injury to the affected arm and chest are important self-management precautions to reduce risk of chronic lymphedema development. BH needs continued support in reviewing evidence-based risk-reduction guidelines and understanding ways to apply them to her lifestyle. In the absence of preoperative baseline or contralateral limb measurements (with circumferences or perometry or water displacement), assessment of limb change at a level identified as diagnostic of lymphedema (commonly, 200-mL volume or 2-cm girth increase from baseline or as compared to the contralateral limb) is very challenging. Without bilateral preop limb measurements for baseline and contralateral limb comparisons, BH might have been diagnosed with lymphedema at postop or at 48 months, when both limbs increased symmetrically. Symptom assessment is also crucial, as symptom report of heaviness and swelling is found to be associated with limb volume changes indicative of lymphedema. Transient hand swelling may be evidence of latent lymphedema and cause for increased risk-reduction education and vigilance in assessment for

  18. Advanced liquefaction using coal swelling and catalyst dispersion techniques

    SciTech Connect

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

    1991-01-01

    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. Work has centered upon obtaining bulk samples of feedstocks for the project, up-dating the background literature, and preparing and testing a computer program to perform material balance calculations for the continuous flow liquefaction unit.

  19. 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.

  20. Preparation and swelling behavior of chitosan-based superporous hydrogels for gastric retention application.

    PubMed

    Park, Hyojin; Park, Kinam; Kim, Dukjoon

    2006-01-01

    Chitosan and glycol chitosan hydrogels were prepared, and their swelling behaviors in acidic solution were studied to investigate their application for gastric retention device. The optimum preparation condition of superporous hydrogels was obtained from the gelation and blowing kinetics measured at varying acidic conditions. Both the swelling rate and swelling ratio of glycol chitosan hydrogels were higher than those of chitosan hydrogels. Swelling behaviors were significantly affected by not only foaming/drying methods but also crosslinking density, as the sizes and structures of pores generated were highly dependent on those preparation conditions. The prepared superporous hydrogels were highly sensitive to pH of swelling media, and showed reversible swelling and de-swelling behaviors maintaining their mechanical stability. The degradation kinetics in simulated gastric fluid was also studied.

  1. Mechanistic interpretation of an observed rate dependence of low temperature swelling of irradiated uranium silicide dispersion fuels

    SciTech Connect

    Rest, J; Hofman, G L

    1990-06-01

    Recent experimental observations on low temperature swelling of irradiated uranium silicide dispersion fuels have indicated that the growth of fission gas bubbles appears to be affected by fission rate. The swelling curve of the material exhibits a distinct knee'' that shifts to higher fission density with increased fission rate due to higher enrichments. Current state-of-the-art models for fission gas behavior do not predict such a dependence. Indirect evidence from various experiments leads the present authors to speculate that a dense network of subgrain boundaries forms at a dose corresponding to the knee'' in the swelling curve, upon which gas bubbles nucleate and then grow at an accelerated rate compared to those in the bulk material. A theoretical formulation is presented wherein the stored energy in the material is concentrated on a network of crystallization'' sites which diminish with dose due to interaction with radiation produced defects (vacancy-impurity pairs). Recrystallization is induced by statistical fluctuations when the energy per site is high enough such that the creation of grain boundary surfaces is offset by the creation of strain free volumes with a resultant net decrease in the free energy of the material. This formulation is shown to provide a reasonable interpretation of the observed phenomena. 11 refs., 7 figs.

  2. Preparation of Silanized-Chitosan via Solution-Casting Method: Study on the Mechanical, Water Adsorption and Swelling Area Properties

    NASA Astrophysics Data System (ADS)

    Saputra, O. A.; Lestari, W. A.; Nauqinida, M.; Prasetyo, W. E.; Handayani, D. S.

    2017-02-01

    Silanizing of chitosan has been prepared using the solution-casting method. The silanizing agent is 3-glycydiloxypropyl trimethoxysilane (GPTMS). The compounding of chitosan/GPTMS was conducted for 1 hour at 80°C by varying GPTMS compound (5-20 wt %) and the final product is referred as Cs/GPTMS. The mechanical properties, including tensile strength, elongation and young modulus were tested according to ASTM D882-02. The addition of 15 % of GPTMS was able to improve the tensile strength value up to 55.66%. However, the elongation decreased to 64.89 %. Moreover, the water adsorption and swelling area properties were studied in this research to evaluate the material ability. Both of water adsorption and swelling area properties decreased by the presence of GPTMS in chitosan. The Cs/GPTMS materials to be promising candidate materials for plastic engineering due to their properties meet the requirement.

  3. 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.

  4. 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.

  5. 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.

  6. Textureless macula swelling detection with multiple retinal fundus images.

    PubMed

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas P; Tobin, Kenneth W; Grisan, Enrico; Favaro, Paolo; Ruggeri, Alfredo; Chaum, Edward

    2011-03-01

    Retinal fundus images acquired with nonmydriatic digital fundus cameras are versatile tools 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 (PoC) applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyze 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 PoC 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 equalizes the image; second, all available views are registered using nonmorphological sparse features; finally, a dense pyramidal optical flow is calculated for all the images and statistically combined to build a naive height 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 μm and to correlate the reconstruction with the swollen location.

  7. Polymer-Induced Swelling of Solid-Supported Lipid Membranes

    PubMed Central

    Kreuzer, Martin; Trapp, Marcus; Dahint, Reiner; Steitz, Roland

    2015-01-01

    In this paper, we study the interaction of charged polymers with solid-supported 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) membranes by in-situ neutron reflectivity. We observe an enormous swelling of the oligolamellar lipid bilayer stacks after incubation in solutions of poly(allylamine hydrochloride) (PAH) in D2O. The positively charged polyelectrolyte molecules interact with the lipid bilayers and induce a drastic increase in their d-spacing by a factor of ~4. Temperature, time, and pH influence the swollen interfacial lipid linings. From our study, we conclude that electrostatic interactions introduced by the adsorbed PAH are the main cause for the drastic swelling of the lipid coatings. The DMPC membrane stacks do not detach from their solid support at T > Tm. Steric interactions, also introduced by the PAH molecules, are held responsible for the stabilizing effect. We believe that this novel system offers great potential for fundamental studies of biomembrane properties, keeping the membrane’s natural fluidity and freedom, decoupled from a solid support at physiological conditions. PMID:26703746

  8. Hydrostatic forces limit swelling of rat ventricular myocardium.

    PubMed

    Pine, M B; Brooks, W W; Nosta, J J; Abelmann, W H

    1981-11-01

    To study ventricular cellular volume regulation when cell membranes and ion pumps cannot prevent swelling, rat ventricular sections were incubated in modified Krebs-Henseleit solutions in which 1) potassium was substituted for sodium, ion for ion; or 2) sodium chloride was reduced to decrease osmolarity to 228, 171, or 114 mosM. Ventricular water, [3H]inulin and [3H]mannitol spaces, potassium, sodium, chloride, and protein contents, and resting transmembrane potentials were measured. Increases in ventricular cellular volume were less than 30% in potassium-substituted and extremely dilute media (114 mosM), in contrast to increases of over 100% in identically treated renal cortical slices. In potassium-substituted solution, the fluid gained by ventricular cells during incubation was hypertonic with respect to the bathing medium. In dilute solution (171 and 114 mosM), ventricular, cellular, and extracellular osmolarities equilibrated only after substantial losses of cellular ions had occurred. These findings support the existence of mechanical limitations to ventricular cellular swelling, which may be caused by a unique network of interstitial collagen present in ventricular myocardium.

  9. Unusual Presentation of Ulcerative Postauricular Swelling as Sebaceous Cell Carcinoma

    PubMed Central

    Chand, Prem; Kumar, Ashok; Singh, Paramjit; Singla, Lakshay

    2016-01-01

    Sebaceous glands have high concentration over head and neck region. Despite high concentration, sebaceous cell adenoma and carcinomas are infrequent. Sebaceous cell carcinoma is an uncommon, cutaneous aggressive tumor arising from the sebaceous glands and seen almost exclusively on the eyelids (75%). It accounts for just 0.2–0.7% of all eyelid tumors in the USA and very few cases that have originated in areas other than the eyelids have been reported. A 67-year-old male presented with swelling (3 cm × 4 cm), on the right postauricular region, since about 1-month. The swelling became ulcerative and associated with progressive tinnitus and hoarseness of voice. The patient was investigated. Fine-needle aspiration cytology suggested sebaceous cell carcinoma. Then excision biopsy was done, and histopathological examination of excised tissue confirmed the diagnosis. Extraorbital sebaceous cell carcinoma is an aggressive and invasive malignancy. It clinically mimics other diseases and is difficult to diagnose. Hence, an accurate and prompt diagnosis is crucial because of its fulminant course, serious associations with Muir-Torre syndrome and high potential for regional and distant metastasis. PMID:27843279

  10. 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.

  11. 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

  12. 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.

  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. The role of grain size in He bubble formation: Implications for swelling resistance

    NASA Astrophysics Data System (ADS)

    El-Atwani, O.; Nathaniel, J. E.; Leff, A. C.; Muntifering, B. R.; Baldwin, J. K.; Hattar, K.; Taheri, M. L.

    2017-02-01

    Nanocrystalline metals are postulated as radiation resistant materials due to their high defect and particle (e.g. Helium) sink density. Here, the performance of nanocrystalline iron films is investigated in-situ in a transmission electron microscope (TEM) using He irradiation at 700 K. Automated crystal orientation mapping is used in concert with in-situ TEM to explore the role of grain orientation and grain boundary character on bubble density trends. Bubble density as a function of three key grain size regimes is demonstrated. While the overall trend revealed an increase in bubble density up to a saturation value, grains with areas ranging from 3000 to 7500 nm2 show a scattered distribution. An extrapolated swelling resistance based on bubble size and areal density indicated that grains with sizes less than 2000 nm2 possess the greatest apparent resistance. Moreover, denuded zones are found to be independent of grain size, grain orientation, and grain boundary misorientation angle.

  15. 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.

  16. Validation and Parameter Sensitivity Tests for Reconstructing Swell Field Based on an Ensemble Kalman Filter.

    PubMed

    Wang, Xuan; Tandeo, Pierre; Fablet, Ronan; Husson, Romain; Guan, Lei; Chen, Ge

    2016-11-25

    The swell propagation model built on geometric optics is known to work well when simulating radiated swells from a far located storm. Based on this simple approximation, satellites have acquired plenty of large samples on basin-traversing swells induced by fierce storms situated in mid-latitudes. How to routinely reconstruct swell fields with these irregularly sampled observations from space via known swell propagation principle requires more examination. In this study, we apply 3-h interval pseudo SAR observations in the ensemble Kalman filter (EnKF) to reconstruct a swell field in ocean basin, and compare it with buoy swell partitions and polynomial regression results. As validated against in situ measurements, EnKF works well in terms of spatial-temporal consistency in far-field swell propagation scenarios. Using this framework, we further address the influence of EnKF parameters, and perform a sensitivity analysis to evaluate estimations made under different sets of parameters. Such analysis is of key interest with respect to future multiple-source routinely recorded swell field data. Satellite-derived swell data can serve as a valuable complementary dataset to in situ or wave re-analysis datasets.

  17. Effects of leaching parameters on swelling behaviors of compacted mudstone used in landfill liner.

    PubMed

    Chen, Hung-Ta; Lin, Tzong-Tzeng; Chang, Juu-En

    2003-03-01

    This study attempt to determine the swelling deformation of compacted mudstone using the free swell test, and the leaching parameters using a pH meter, a conductivity meter, and ion chromatography (IC) techniques. Closely examining chemical characteristics indicated that natural mudstone is saline-alkali soil. The maximum swelling deformation obtained from the free swell test is about 15.7%. The swelling developed relatively rapidly after the start of soaking, stopping after 7 days. The leaching characteristics in compacted mudstone involve the hydrolysis of Na+ ions, the precipitation of CaCO3 and slightly dissolution of Mg2+ ion. The relationship of swelling deformation to sodium adsorption ratio (SAR) value indicated that the SAR value in soaking suspension significantly affects the amount of swelling. Additionally, the pH of the soaking suspension importantly affects swelling behavior. Overall, the early swelling behaviors of compacted mudstone are posited to involve directly the concentration of Na+ ions in the soaking suspension and the precipitation of CaCO3 in compacted mudstone. Furthermore, the very slight swelling after the 3-day soaking is related to the dissolution of Mg2+ ions in compacted mudstone.

  18. Validation and Parameter Sensitivity Tests for Reconstructing Swell Field Based on an Ensemble Kalman Filter

    PubMed Central

    Wang, Xuan; Tandeo, Pierre; Fablet, Ronan; Husson, Romain; Guan, Lei; Chen, Ge

    2016-01-01

    The swell propagation model built on geometric optics is known to work well when simulating radiated swells from a far located storm. Based on this simple approximation, satellites have acquired plenty of large samples on basin-traversing swells induced by fierce storms situated in mid-latitudes. How to routinely reconstruct swell fields with these irregularly sampled observations from space via known swell propagation principle requires more examination. In this study, we apply 3-h interval pseudo SAR observations in the ensemble Kalman filter (EnKF) to reconstruct a swell field in ocean basin, and compare it with buoy swell partitions and polynomial regression results. As validated against in situ measurements, EnKF works well in terms of spatial–temporal consistency in far-field swell propagation scenarios. Using this framework, we further address the influence of EnKF parameters, and perform a sensitivity analysis to evaluate estimations made under different sets of parameters. Such analysis is of key interest with respect to future multiple-source routinely recorded swell field data. Satellite-derived swell data can serve as a valuable complementary dataset to in situ or wave re-analysis datasets. PMID:27898005

  19. Interpretation of Coal-Seam Sequestration Data Using a New Swelling and Shrinkage Model

    SciTech Connect

    Siriwardane, H.J.; Smith, D.H.

    2006-10-01

    This paper deals with the influence of swelling and shrinkage of coal on the production of methane from, and sequestration of carbon dioxide in, a coalbed reservoir. A three-dimensional swelling and shrinkage model was developed. It is based on constitutive equations that account for coupled fluid pressure-deformation behavior of a porous medium that undergoes swelling and shrinkage. The swelling and shrinkage strains are computed on the basis of the amounts of different gases (e.g., CO2, CH4) sorbed or desorbed. The amounts of sorption and desorption are computed from measured isotherms with the aid of the Ideal Adsorbed Solution model for mixed gases. The permeability of the reservoir is modified according to the swelling-shrinkage model. The paper presents numerical results for the influence of swelling and shrinkage on reservoir performance during injection of carbon dioxide. The paper includes results from a number of examples, and analysis of a field injection into a coal seam at a site in the San Juan basin. Results show that with the incorporation of swelling and shrinkage into the analysis, it is possible to get a better history-match of production data. Results also show that coal swelling can reduce the injection volumes of carbon dioxide significantly. The interpretation of field data with the new swelling-shrinkage model shows that the coal swelling during carbon dioxide sequestration in coal-seams is an important factor that can influence field performance.

  20. 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.

  1. 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.; ...

    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

  2. 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.

  3. 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

  4. Biomass-Swelling Assisted Synthesis of Hierarchical Porous Carbon Fibers for Supercapacitor Electrodes.

    PubMed

    Liu, Yang; Shi, Zijun; Gao, Yanfang; An, Weidan; Cao, Zhenzhu; Liu, Jinrong

    2016-02-16

    The preparation of porous materials from renewable energy sources is attracting intensive attention due to in terms of the application/economic advantage, and pore structural design is core in the development of efficient supercapacitors or available porous media. In this work, we focused on the transformation of natural biomass, such as cotton, into more stable porous carbonaceous forms for energy storage in practical applications. Biomorphic cotton fibers are pretreated under the effect of NaOH/urea swelling on cellulose and are subsequently used as a biomass carbon source to mold the porous microtubule structure through a certain degree of calcining. As a merit of its favorable structural features, the hierarchical porous carbon fibers exhibit an enhanced electric double layer capacitance (221.7 F g(-1) at 0.3 A g(-1)) and excellent cycling stability (only 4.6% loss was observed after 6000 cycles at 2 A g(-1)). A detailed investigation displays that biomass-swelling behavior plays a significant role, not only in improving the surface chemical characteristics of biomorphic cotton fibers but also in facilitating the formation of a hierarchical porous carbon fiber structure. In contrast to traditional methods, nickel foams have been used as the collector for supercapacitor that requiring no additional polymeric binders or carbon black as support or conductive materials. Because of the absence of additive materials, we can further enhance capacitance. This remarkable capacitive performance can be due to sufficient void space within the porous microstructure. By effectively increasing the contact area between the carbon surface and the electrolyte, which can reduce the ion diffusion pathway or buffer the volume change during cycling. This approach opens a novel route to produce the abundantly different morphology of porous biomass-based carbon materials and proposes a green alternative method to meet sustainable development needs.

  5. 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.

  6. Ultrastructural alterations of human cortical capillary basement membrane in human brain oedema.

    PubMed

    Castejón, Orlando José

    2014-01-01

    The capillary basement membranes are examined in severe traumatic brain injuries, vascular malformation, congenital hydrocephalus and brain tumours. They exhibit homogeneous and nodular thickening, vacuolization, rarefaction, reduplication, and deposition of collagen fibers. Their average thickness varied according to the aetiology and severity of brain oedema. In moderate brain oedema the thickness ranged from 71.97 to 191.90 nm in width, and in patients with severe brain oedema it varied from 206.66 to 404.22 nm. The basement membrane complex appears apparently intact in moderate oedema, and shows glio-basal dissociation in severe oedema. In areas of highly increased cerebro-vascular permeability, the basement membrane shows matrix disorganization, reduplication, and bifurcations protruding toward the endothelial cells, and acting as abluminal transcapillary channels. In regions of total brain necrosis, its structural stability is lost showing loosening, dissolution and rupture. Basement membrane swelling is due to overhydration of its protein-complex glycoprotein matrix. The thickening, rarefaction and vacuolization are induced by the increased vacuolar and vesicular transendothelial transport. The degenerated basement membrane areas exhibit a finely granular precipitate interpreted as protein, proteoglycan, glycoprotein, and agrin degraded matrix.

  7. 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.

  8. Idiopathic facial swelling secondary to sickle cell anaemia.

    PubMed

    Moghe, Swapnil; Pillai, Ajay; Guru, Kanishka Navin; Nair, Preeti P

    2012-10-10

    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.

  9. 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.

  10. 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.

  11. Swelling and surface modification of ultrathin chitosan films

    NASA Astrophysics Data System (ADS)

    Murray, Chris

    2005-03-01

    Chitosan is a biodegradable polysaccharide derived from seashell waste products. The high water absorbency and biocompatibility of chitosan have enabled its use as a hydrogel in specialty biomedical applications. We present the results of several experiments focused on characterizing properties of ultrathin films of chitosan critical to their use in techniques such as wound dressings, medical implants and drug delivery systems. Uniform thin films with thicknesses of 15 to 600 nm and rms roughness of the order of 1 nm were prepared using techniques previously developed in our research group. The swelling of these films in the presence of high humidity has been characterized using reflection ellipsometry, atomic force microscopy and quartz crystal microbalance techniques. The effects of exposure to elevated temperature and UV/ozone (a common surface modification technique) on the surface properties such as hydrophobicity are described.

  12. Comment on 'Large Swelling and Percolation in Irradiated Zircon'

    SciTech Connect

    Corrales, Louis R.; Weber, William J.; Chartier, Alain; Meis, Constantin; Crocombette, J.-P.

    2003-09-24

    A recent model for the large radiation-induced swelling behavior in irradiated zircon (ZrSiO4) is partially based on results of molecular dynamics simulations of the partial overlap of two collision cascades that predict a densified boundary of polymerized silica and the scattering of the second cascade away from the densified boundary (Trachenko K, Dove M T and Salje E K H 2003 J. Phys.: Condens. Matter 15 L1). These MD simulations are based on an atomic interaction potential for zircon (Trachenko K, Dove MT and Salje EKH 2001 J. Phys.: Condens. Matter 13 1947) for which, according to our analysis, only reproduces some of the crystallographic properties at equilibrium and do not adequately describe the scattering physics for zircon, and on simulation methodologies for which the standard procedures for boundary conditions of energetic events are ill-defined. In fact, the interatomic potential model used by Tranchenko et al yields a significantly more rigid structure, with very high Frenkel defect formation energies and extremely low entropy and specific heat capacity. The synergy of all these unphysical properties for zircon, naturally leads to highly localized collision cascades. Consequently, the reported results of the cascade simulations, which are events far from equilibrium, may be artifacts of both the potential model and simulation methodologies employed. Thus, the structural changes predicted by the simulations must be viewed cautiously, and these simulations results cannot be taken as confirmation of a new scattering physics process that is the basis for the proposed swelling model. In this comment, the deficiencies in the atomic interaction potential and methodologies employed by these authors are critically reviewed, and the validity of the cascade overlap simulations and proposed physics is discussed.

  13. 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.

  14. 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.

  15. Unexpected Swelling of Stiff DNA in a Polydisperse Crowded Environment.

    PubMed

    Kang, Hongsuk; Toan, Ngo Minh; Hyeon, Changbong; Thirumalai, D

    2015-09-02

    We investigate the conformations of DNA-like stiff chains, characterized by contour length (L) and persistence length (lp), in a variety of crowded environments containing monodisperse soft spherical (SS) and spherocylindrical (SC) particles, a mixture of SS and SC, and a milieu mimicking the composition of proteins in the Escherichia coli cytoplasm. The stiff chain, whose size modestly increases in SS crowders up to ϕ ≈ 0.1, is considerably more compact at low volume fractions (ϕ ≤ 0.2) in monodisperse SC particles than in a medium containing SS particles. A 1:1 mixture of SS and SC crowders induces greater chain compaction than the pure SS or SC crowders at the same ϕ, with the effect being highly nonadditive. We also discover a counterintuitive result that the polydisperse crowding environment, mimicking the composition of a cell lysate, swells the DNA-like polymer, which is in stark contrast to the size reduction of flexible polymers in the same milieu. Trapping of the stiff chain in a fluctuating tube-like environment created by large-sized crowders explains the dramatic increase in size and persistence length of the stiff chain. In the polydisperse medium, mimicking the cellular environment, the size of the DNA (or related RNA) is determined by L/lp. At low L/lp, the size of the polymer is unaffected, whereas there is a dramatic swelling at an intermediate value of L/lp. We use these results to provide insights into recent experiments on crowding effects on RNA and also make testable predictions.

  16. 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.

  17. 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.

  18. 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...

  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. 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.

  1. 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.

  2. The swelling of mitochondria from nitrogen gas; a possible cause of reperfusion damage.

    PubMed

    VanDeripe, Donald R

    2004-01-01

    Electron photomicrograph evidence is presented which suggests that the in vivo swelling of mitochondria may result from the uptake of nitrogen gas bubbles which coalesce to fill the intramitochondrial space during tissue anoxia. These observations have led to the hypothesis that nitrogen-filled mitochondria are unable to take up oxygen resulting in cell death. A test of this hypothesis also represents a probable treatment for stroke, namely the total body washout of nitrogen. This can be achieved by the inhalation of an oxygen-helium mixture with exhaled gases shunted to ambient atmosphere. This washout should facilitate nitrogen egress from the interior of affected mitochondria, allow oxygen uptake and a resumption of oxidative metabolism. This hypothesis generally fits well with the literature on luxury perfusion following stroke. In cases of luxury perfusion the venous blood exiting the lesion is red indicating a decreased transfer of oxygen to the extracellular and cytosolic fluids. However, whereas luxury perfusion assumes blood flow adequate for delivery of oxygen to the tissues, this hypothesis interjects a blockade at the level of oxygen uptake into mitochondria, and unless this blockade is reversed it will lead to cell death and brain tissue necrosis in the affected regions.

  3. Can fertility signals lead to quality signals? Insights from the evolution of primate sexual swellings

    PubMed Central

    Huchard, Elise; Courtiol, Alexandre; Benavides, Julio A.; Knapp, Leslie A.; Raymond, Michel; Cowlishaw, Guy

    2009-01-01

    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). PMID:19324772

  4. 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

  5. LRRC8A protein is indispensable for swelling-activated and ATP-induced release of excitatory amino acids in rat astrocytes

    PubMed Central

    Hyzinski-García, María C; Rudkouskaya, Alena; Mongin, Alexander A

    2014-01-01

    In mammals, cellular swelling activates release of small organic osmolytes, including the excitatory amino acids (EAA) glutamate and aspartate, via a ubiquitously expressed volume-regulated chloride/anion channel (VRAC). Pharmacological evidence suggests that VRAC plays plural physiological and pathological roles, including excitotoxic release of glutamate in stroke. However, the molecular identity of this pathway was unknown. Two recent studies discovered that LRRC8 gene family members encode heteromeric VRAC composed of LRRC8A plus LRRC8B-E, which mediate swelling-activated Cl− currents and taurine release in human non-neural cells (Z. Qiu et al. Cell 157: 447, 2014; F.K. Voss et al. Science 344: 634, 2014). Here, we tested the contribution of LRRC8A to the EAA release in brain glia. We detected and quantified expression levels of LRRC8A-E in primary rat astrocytes with quantitative RT-PCR and then downregulated LRRC8A with gene-specific siRNAs. In astrocytes exposed to hypo-osmotic media, LRRC8A knockdown dramatically reduced swelling-activated release of the EAA tracer d-[3H]aspartate. In parallel HPLC assays, LRRC8A siRNA prevented hypo-osmotic media-induced loss of the endogenous intracellular l-glutamate and taurine. Furthermore, downregulation of LRRC8A completely ablated the ATP-stimulated release of d-[3H]aspartate and [14C]taurine from non-swollen astrocytes. Overall, these data indicate that LRRC8A is an indispensable component of a permeability pathway that mediates both swelling-activated and agonist-induced amino acid release in brain glial cells. PMID:25172945

  6. Failed First Craniotomy and Tumor Removal of Parasagittal Meningioma with Severe Peritumoral Brain Edema

    PubMed Central

    Shim, Youngbo

    2016-01-01

    Parasagittal meningioma often presents as peritumoral brain edema (PTBE). The risk of edema increases when the tumor occludes the superior sagittal sinus (SSS). Although PTBE may be expected based on the patient’s symptoms or radiologic findings, extensive brain swelling and extracranial herniation during elective surgery are rare. Herniation during surgery could lead to irreversible neurological damage and even brain rupture. We report a case of a failed routine craniotomy for a parasagittal meningioma with complete occlusion of the posterior third of the SSS in a 30-year-old male patient. The patient developed extensive brain swelling and extracranial herniation during surgery. PMID:27867923

  7. 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.

  8. Acute Submandibular Swelling Complicating Arteriography With Iodide Contrast

    PubMed Central

    Zhang, Guilian; Li, Yaqi; Zhang, Ru; Guo, Yingying; Ma, Zhulin; Wang, Huqing; Zhang, Lei; Li, Tingting

    2015-01-01

    Abstract Iodide mumps is an uncommon condition induced by iodide-containing contrast. We present the first reported case of iodide mumps in mainland China, which occurred after carotid artery intervention. The patient, a 65-year-old Chinese male, had a history of dizziness, hypertension, diabetes, and right arm weakness. He had no history of allergies and had never previously received iodide-containing contrast. The patient's kidney function and other laboratory findings were normal. He underwent stenting of the left internal carotid artery (LICA) opening and received approximately 250 mL of a nonionic contrast agent (ioversol). Approximately 5 hours after angioplasty, bilateral local swellings were noted near the mandible; the masses were moderately firm and nontender. Iodide mumps was diagnosed in the patient. Intravenous dexamethasone (10 mg) was administered. The submandibular glands had shrunk by 11 hours after angioplasty, and they gradually became softer. The mandibular salivary glands had completely recovered by 5 days after surgery. Iodide mumps represents a rare late reaction to iodine-containing contrast media. This condition can occur in any patient receiving any iodinated contrast agent and may recur upon repeated exposure, but self-resolution can be expected within 2 weeks. All clinicians who use contrast media or iodide should be aware of this condition. PMID:26287428

  9. 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.

  10. 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

  11. 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

  12. Calcium-alginate hydrogel swelling models are not pH-dependent.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent article by Koc et al. (2008) reports predictive models for the swelling behavior of calcium-alginate hydrogels in response to changes in pH and temperature. We submit that the reported effect of “pH” on hydrogel swelling is unsupported by the data and is more properly interpreted as the ...

  13. [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.

  14. 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.

  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. Facial swelling secondary to inhaled bronchodilator abuse: catecholamine-induced sialadenosis.

    PubMed

    Loria, R C; Wedner, H J

    1989-04-01

    A patient with asthma presented with a history of recurrent episodes of facial swelling. The swelling occurred in the preauricular area and extended to the angle of the jaw. The patient attributed these episodes to a "food allergy" as they occurred during or immediately following meals. The only medication the patient was using was inhaled epinephrine (Primatene MistR), two puffs, ten to twenty times a day. Subsequent evaluation revealed that the patient had sarcoidosis. Differential diagnosis of the facial swelling included food-related angioedema, sarcoid parotitis, or catecholamine-induced sialadenosis, which is a rare complication associated with excessive catecholamine administration. A gallium-67 citrate scan demonstrated abnormal pulmonary and hilar uptake of the radiotracer, but not lacrimal or parotid gland uptake, strongly arguing against sarcoidosis as the cause of the facial swelling. Episodes of swelling completely abated when the patient stopped using the epinephrine inhalers. At 5 months of follow-up she has had two recurrent episodes of facial swelling, each time associated with the use of inhaled epinephrine. Thus this patient's facial swelling most likely represents catecholamine-induced sialadenosis. This adverse drug reaction, associated with excessive use of inhaled catecholamines must be kept in mind in patients who abuse inhaled beta-adrenergic agonists and report parotid swelling.

  17. 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.

  18. Dynamic Validation of Envisat ASAR Derived Ocean Swell Against Directional Buoy Measurements in Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Wang, He; Mouche, Alexis; Husson, Romain; Chapron, Bertrand

    2016-08-01

    Advanced Synthetic Aperture Radar (ASAR) in wave mode aboard Envisat satellite from ESA provides the unique 10-years swell spectra dataset on a continuous and global basis for scientific community. In this paper, a method of a dynamical validation approach for SAR swell spectra is developed, in which the in situ buoy spectra are reconstructed, partitioned, and retro- propagated to the vicinity of satellite observation along the great circle based upon the linear wave theory. More than 40,000 ASAR-buoy swell partitions are dynamically collocated for the full mission of Envisat, making this study the first to provide detailed quality assessment for ASAR derived ocean swell spectra. Comparison results show a general statistics of 0.40 m, 44.99 m and 16.89 ̊ for swell height, peak wavelength and direction RMSE, indicating a good agreement with buoy in-situ in Pacific Ocean.

  19. Synthesis, characterization and swelling behavior of superabsorbent wheat straw graft copolymers.

    PubMed

    Li, Qian; Ma, Zuohao; Yue, Qinyan; Gao, Baoyu; Li, Wenhong; Xu, Xing

    2012-08-01

    Swelling behavior is an important characteristic for superabsorbents. A wheat straw-based superabsorbent (WS-SAB) was prepared by graft copolymerization of acrylic acid, acrylic amide and dimethyl diallyl ammonium chloride onto the cellulose of wheat straw, and its swelling and deswelling behavior was investigated. The product had a water absorbency of 133.76 g/g in distilled water and 33.83 g/g in 0.9 wt.% NaCl solution. Fourier transform infrared spectroscopy and scanning electron microscopy indicated that the monomers were successfully grafted onto the wheat straw. The largest swelling capacity was at pH 6. The effect of ions on the swelling was in the order: Na(+)>K(+)>Mg(2+)>Ca(2+) and Cl(-)>SO(4)(2-). The swelling capacity did not change after several times of water absorption and release.

  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. Effect of Phbv Content on the Transparency and Swelling Behavior of Polymer/hectorite Nanocomposite Hydrogel

    NASA Astrophysics Data System (ADS)

    Zhang, Qingsong; Zhao, Yiping; Chen, Li

    As a kind of novel biopolymer material with good biodegradability and biocompatibility, poly(β-hydroxybutyrate-co-valerate)(PHBV) was introduced into organic/inorganic network structure of nanocomposite hydrogels prepared by in-situ free-radical polymerization based on monomer N-isopropylacrylamide(NIPAM) and physical cross-linker hectorite. As viewed from appearance of the hydrogels, obvious change occurred from transparent to white with the increase of PHBV content, which reflects the structural shift from homogeneity to inhomogeneity. The swelling ratio and swelling kinetics of thermo-sensitive poly(NIPAM/PHBV/Hectorite) hydrogels with different PHBV content was investigated by gravimetric method. It was found that the incorporation of PHBV decreases the swelling ratio of pure poly(NIPAM/Hectorite) hydrogels on account of hydrophobicity of PHBV. Furthermore, in the case of swelling kinetics, the result of linear regression shows that relaxation of polymer chains of the hydrogels controls the swelling process.

  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. 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.

  4. The Measurement of Polymer Swelling Processes by an Interferometric Method and Evaluation of Diffusion Coefficients

    PubMed Central

    Mráček, Aleš

    2010-01-01

    The amorphous polymer film swelling in a liquid solvent below the glass transition temperature was characterized by a few kinetic parameters (especially the mutual diffusion coefficient of swelling and its mean value) obtained by interference of monochromatic light in the wedge arrangement. This interferometric method allows one to determine the concentration field in the swollen surface layer and consequently to compute the concentration-dependent diffusion coefficient. A software system developed at the Department of Physics and Material Engineering at TBU in Zlin has been used for the evaluation of the main kinetic parameters of the swelling process. The software can be used for the on-line analyses of interferograms during the swelling process. The main application outputs are the computation of the concentration profile, the concentration gradient, the mutual diffusion coefficient of the swelling by the solvent and its mean value. PMID:20386653

  5. 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 ...

  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. 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.

  8. 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.)

  9. 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

  10. Report on fundamental modeling of irradiation-induced swelling and creep in FeCrAl alloys

    SciTech Connect

    Kohnert, Aaron A.; Dasgupta, Dwaipayan; Wirth, Brian; Linton, Kory D.

    2016-09-23

    In order to improve the accident tolerance of light water reactor (LWR) fuel, alternative cladding materials have been proposed to replace zirconium (Zr)-based alloys. Of these materials, there is a particular focus on iron-chromium-aluminum (FeCrAl) alloys due to much slower oxidation kinetics in high-temperature steam than Zr-alloys. This should decrease the energy release due to oxidation and allow the cladding to remain integral longer in the presence of high temperature steam, making accident mitigation more likely. As a continuation of the development for these alloys, the material response must be demonstrated to provide suitable radiation stability, in order to ensure that there will not be significant dimensional changes (e.g., swelling), as well as quantifying the radiation hardening and radiation creep behavior. In this report, we describe the use of cluster dynamics modeling to evaluate the defect physics and damage accumulation behavior of FeCrAl alloys subjected to neutron irradiation, with a particular focus on irradiation-induced swelling and defect fluxes to dislocations that are required to model irradiation creep behavior.

  11. Catalytic activity enhancement by thermal treatment and re-swelling process of natural containing iron-clay for Fenton oxidation.

    PubMed

    Ausavasukhi, Artit; Sooknoi, Tawan

    2014-12-15

    In this research, catalytic activity of the modified natural containing Fe-clay, Fenton-like catalyst, toward successful decolorization of methylene blue (MB) and degradation of phenol (PhOH) was demonstrated. Among the natural containing Fe-clay prepared only by thermal treatment, the sample treated at 500°C provides a high Fenton oxidation activity presumably due to high number of available Fe active sites. However, the efficient use of treated natural containing Fe-clay is restricted due to the loss in BET surface area during thermal treatment process. Interestingly, modification by the thermal treatment and subsequent re-swelling cannot only generate the active Fe species, but also enhance the basal space that facilitates diffusion of the reagents toward the active sites within the clay layers. It is expected that the active Fe species formed and retained by thermal treatment and re-swelling process which is on the surface of the catalyst reacts with hydrogen peroxide and leads to the formation of active oxidant that remove the MB and PhOH.

  12. 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.

  13. 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.

  14. Swelling and mechanical properties of biopolymer hydrogels containing chitosan and bovine serum albumin.

    PubMed

    Butler, Michael F; Clark, Allan H; Adams, Sarah

    2006-11-01

    Experimental and theoretical investigations of the swelling and mechanical properties of hydrogels formed from chitosan, bovine serum albumin (BSA), and chitosan/BSA mixtures cross-linked with genipin were performed. The properties of cross-linked chitosan hydrogels were explained in terms of its polyelectrolyte behavior, which led to a gradual increase in swelling ratio below the pK value, but whereby its swelling ability was eliminated by the presence of salt that screened the charges. Comparison of theoretical and experimental calculations of the swelling ratio, however, indicated that complications arising from wastage of cross-links, and formation of polymerized genipin cross-links must be considered before quantitative prediction can be achieved. Cross-linked BSA hydrogels swelled even in the presence of salt, and a marked increase in swelling was observed below pH = 3 that was explained as the result of an acid induced denaturation of the protein that led to unfolding of the molecule. Swollen BSA hydrogels were mechanically weak, however. Composite gels made from a cross-linked mixture of chitosan and BSA exhibited the swelling behavior of BSA combined with the mechanical properties of chitosan and were therefore considered most suitable for use in a gastric environment.

  15. 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.

  16. Adrenal chromaffin cells do not swell when exposed to nanosecond electric pulses.

    PubMed

    Craviso, Gale L; Fisher, Christa; Chatterjee, Indira; Vernier, P Thomas

    2015-06-01

    High intensity, nanosecond duration electric pulses (NEPs) permeabilize plasma membranes causing osmotic cell swelling that can elicit a wide variety of cellular effects. This study examined the possibility that cell swelling is the mechanism by which 5 ns NEPs trigger the release of catecholamines from neuroendocrine adrenal chromaffin cells. Swelling was assessed by comparing measurements of cell area obtained from bright field images of the cells before and at 10s intervals following exposure of the cells to 5 ns pulses at a field intensity of 5-6 MV/m. The results indicated that chromaffin cells do not swell in response to a single pulse or a train of ten pulses delivered at repetition frequencies of 10 Hz and 1 kHz. Swelling was also not observed in response to a train of 50 pulses whereas Jurkat T lymphoblast cell area increased 15% on average under the same NEP exposure conditions. These results demonstrating that chromaffin cells do not undergo swelling when exposed to 5 ns NEPs have important implications regarding the mechanism by which these pulses stimulate the release of catecholamines from these cells, namely that catecholamine secretion is most likely not caused by cell swelling.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Swelling-induced Cl- current in guinea-pig atrial myocytes: inhibition by glibenclamide.

    PubMed Central

    Sakaguchi, M; Matsuura, H; Ehara, T

    1997-01-01

    1. Whole-cell currents were recorded from guinea-pig atrial myocytes using the patch-clamp technique under conditions designed to block K+ channels, Ca2+ channels and electrogenic transporters. 2. Exposure of atrial myocytes to the hyposmotic external solution (Na+ reduction to about 70% of control) resulted in hyposmotic cell swelling which was associated with activation of an outwardly rectifying Cl- current (ICl,swell). 3. Whereas the activation of ICl,swell was not significantly affected by replacement of ATP in the pipette solution with the non-hydrolysable ATP analogue 5'-adenylyl-imidodiphosphate (AMP-PNP), its activation was greatly reduced in cells dialysed with an ATP-free pipette solution, thus indicating that the activation process of ICl,swell requires the presence of intracellular ATP, but not its hydrolysis. 4. Bath application of glibenclamide produced a concentration-dependent block of ICl,swell with a half-maximal inhibitory concentration (IC50) of 60.0 microM and a Hill coefficient of 2.1. The maximal effect (100% inhibition) was obtained with 500 microM glibenclamide. The steady-state inhibition showed little voltage dependence, while glibenclamide at concentrations of more than 100 microM inhibited the outward ICl,swell more rapidly than the inward ICl,swell. The glibenclamide inhibition was fully reversible after removal of the drug, even when a maximal effect (full inhibition) was achieved at a high drug concentration (500 microM). 5. These results show that (i) glibenclamide is one of the most potent inhibitors of guinea-pig atrial ICl,swell, and (ii) atrial ICl,swell and the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- currents are almost equally sensitive to inhibition by glibenclamide. Images Figure 1 PMID:9409470

  2. Anesthetic concerns in a huge congenital sublingual swelling obscuring airway access

    PubMed Central

    Kumar, Nilesh; Bindra, Ashish; Kumar, Niraj; Yadav, Naveen; Sharma, Shilpa

    2015-01-01

    Presence of intraoral pathology poses a great challenge during management of pediatric airway. We report management of big intraoral cystic swelling physically occupying the entire oral cavity restricting access to airway. Preintubation aspiration of swelling was done to decrease its size and make room for airway manipulation, followed by laryngoscopy and intubation in lateral position. Airway patency is at risk in postoperative period also, in this case, though the swelling decreased in size postoperatively but presence of significant edema required placement of tongue stitch and modified nasopharyngeal airway. Case report highlights simple maneuvers to manage a difficult case. PMID:25829912

  3. 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.

  4. Swell Activity in the Southern Pacific From Seismic and Infrasonic Data

    NASA Astrophysics Data System (ADS)

    Reymond, D.; Barruol, G.; Fontaine, F.; Hyvernaud, O.; Maurer, V.; Maamaatuaiahutapu, K.

    2004-12-01

    A temporary network of 10 broad band seismic stations has been deployed in French Polynesia for the Polynesian Lithosphere and Upper Mantle Experiment (PLUME). The stations are installed either on volcanic islands or on atolls of the various archipelagos of French Polynesia to complement the geographic coverage provided by the permanent stations. At all sites, the proximity of the ocean generates a high microseismic noise level. The power spectral density of the seismic data show clear peaks in the 0.05 to 0.09 Hz frequency range (11 to 20 s period), corresponding to typical swell frequencies. In this single frequency peak, the swell-related seismic signal is elliptically polarized and is contained within the horizontal plane. We measure hourly its amplitude and azimuth and demonstrate that in this frequency range, the amplitude of the microseismic "noise" shows very similar variations from station to station and is strongly correlated with the swell amplitude predicted by the NOAA, wind-derived, "WaveWatch" models. Deducing the swell direction from the ground particle motion has to be done with care since the island ground motion can be strongly controlled by local swell refraction processes. We find cases, however, such as in Tahiti or on roughly circular atolls, for which the azimuth of the incoming swell may be well deduced from the seismic data. This therefore demonstrates that the swell-related seismic signal observed in French Polynesia in the single frequency peak can reliably be used as a proxy for swell amplitude and azimuth. The presence of an infrasonic array installed in Tahiti also provides the opportunity to use microbarometric signal to characterize the swell activity. For a period of low wind (which is a strong noise generator) and high swell, we evidenced a clear correlation between the microseismic and infrasonic noise amplitude, together with the predicted and the locally observed swell amplitudes, suggesting that such infrasonic data can be

  5. 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

  6. 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.

  7. Anomalous Shrinking-Swelling of Nanoconfined End-Charged Polyelectrolyte Brushes: Interplay of Confinement and Electrostatic Effects.

    PubMed

    Chen, Guang; Das, Siddhartha

    2016-07-14

    In this article, we model the structure and configuration of the end-charged polyelectrolyte (PE) brushes grafted on the inner walls of a nanochannel. When the confinement effect is weak, that is, d0 < h/2 (d0 is the PE brush height without electrostatic effects and h is the nanochannel half-height), d < d0 (d is the brush height with the electrostatic effects), that is, the brushes shrink due to the electrostatic effects. Furthermore, for this case, an increase in salt concentration increases d. On the contrary, for the case in which the confinement effect is strong (i.e., d0 > h/2), d > d0 (i.e., the electrostatic effects swell the brushes), and an increase in salt concentration decreases the brush height. These findings reveal that the behavior of the end-charged brushes shows three unique differences when compared to that of the standard PE brushes with charges along their entire backbone. These differences are (a) the presence of a distinct role of the confinement in dictating how the electrostatic effects mediated by the electric double layer govern the height of end-charged brushes, (b) electrostatic-effect-driven shrinking of end-charged brushes for d0 < h/2 (for backbone-charged brushes, the electrostatic effects always swell the brushes), and (c) swelling of end-charged brushes with an increase in salt concentration for d0 < h/2 (backbone-charged brushes always shrink with an increase in salt concentration). Such unique effects of confinement and electrostatics on PE brushes have not been reported previously, and we anticipate that these findings will shed new light on the structure and properties of PE-brush-functionalized nanochannels with implications in applications such as fabrication of functionalized-nanochannel-based nanofluidic diodes, valves, biosensors, current rectifiers, and so forth.

  8. Molecular Mechanisms Involved in Tissue Swelling Due to Injury and Due to Exposure to Low Temperature and Massive Water and Electrolyte Loss in Diarrheal Disorders.

    DTIC Science & Technology

    1985-05-28

    Continue on revese aide It neceeeary aid Identiiy by block number) ion adsorption, water polarization, ATP , cell injury, NMR 20. ABSTRACT (Continue on...K+ and extrude Nat in the presence of ATP . Only "red ghosts" which have re- tained hemoglobin and other cytoplasmic proteins reaccumulate K+ and... ATP content. Both sets of results confirm prediction of the AI hypo- thesis Accession For NfIIS GRAMI DTIC TAB Unannounced 0 Justificatio Distribut

  9. Molecular Mechanisms Involved in Tissue Swelling due to Injury and due to Exposure to Low Temperature and Massive Water and Electrolyte Loss in Diarrheal Disorders,

    DTIC Science & Technology

    1980-10-06

    MNLOV HUIA Ol 1N I ’ 1 1 A111 OFFICE OF NAVAL RESEARCH - BIOPHYSICS PROGRAM - RESEARCH PR.PDSAL 1. TITLE OF RESEARCH PROPOSAL: "Molecular Mecharisms...move- ment and which has some of the characteristics of a metabolic process , such as sen- sitivity to metaolic inhibitors and a Iigh temperature...STREETS MHD.ADMPHA. PENNSYLVANIA 19107 TEiI PONE (21S) 829/ November 10, 1980 Mrs. Farrington Office of Naval Research Code 613 1F 800 N. Quincy St

  10. Molecular Mechanisms Involved in Tissue Swelling due to Injury and due to Exposure to Low Temperature and Massive Water and Electrolyte Loss in Diarrheal Disorders.

    DTIC Science & Technology

    1981-10-01

    of the 0- and Y-carboxyl groups of the muscle cells). (i) Edelmann (5, 6, 7): frozen dried- and dry-cut unfixed and unstained frog mus- cle cells with...single fibers (7). (iii) Edelmann (9), using dispersive x-ray microprobe analysis showed concentration of surrogate Cs, Tl? as well as K in normal Kin...isolated air-dried honey been myofibrils (10). (iv) Edelmann (11), using both x-ray microprobe analysis as well as laser microprobe mass spectrometer

  11. Hydrolytically degradable hyperbranched PEG-polyester adhesive with low swelling and robust mechanical properties.

    PubMed

    Zhang, Hong; Zhao, Tianyu; Duffy, Patrick; Dong, Yixiao; Annaidh, Aisling Ní; O'Cearbhaill, Eoin; Wang, Wenxin

    2015-10-28

    Photocrosslinkable and water soluble hyperbranched PEG-polyester polymers (HPEGDA) have been developed as robust degradable adhesives. The HPEGDA polymers have been synthesized from controlled homopolymerization of poly(ethylene glycol) diacrylate (PEGDA700 ) via in situ deactivation enhanced atom transfer radical polymerization (DE-ATRP). By introducing a high initiator-to-monomer ratio, the obtained HPEGDA polymer is composed of extremely short carbon-carbon backbones interconnected together by the long PEG chains as well as pendent photocrosslinkable acrylate moieties. Due to the extremely short C-C backbone, the long PEG chains can therefore be seen as the main chain, thus, HPEGDA polymers behave more like polyester which is a category of polymers that contain the ester functional group in their main chain. Photo-cured HPEGDA can be readily adhered to tissue forming a patch with robust mechanical and adhesive strengths. The degradation profile by hydrolysis of polyester blocks as well as a significantly low swelling ratio of HPEGDA gels in an aqueous environment allow them to have great potential for sealing and repair of internal tissue. Furthermore, HPEGDA gels appear to have minor significant cytotoxicity in vitro. These unique properties indicate that the reported HPEGDA polymers are well poised for the development of adhesive tissue engineering matrixes, wound dressings, and sealants.

  12. Visual loss and optic nerve head swelling in thiamine deficiency without prolonged dietary deficiency

    PubMed Central

    Gratton, Sean M; Lam, Byron L

    2014-01-01

    Visual loss due to optic neuropathy is a rare manifestation of thiamine deficiency. We report a case of a 39-year-old woman with a body mass index (BMI) of 29 kg/m2 who developed visual loss and bilateral optic nerve head swelling after a short, self-limited gastrointestinal illness. She was disoriented and inattentive and had absent ankle jerk reflexes, diminished sensation in both legs below the knees, and marked truncal ataxia. Magnetic resonance imaging (MRI) showed increased T2-signal in the medial thalami and mammillary bodies. The serum thiamine level was 8 nmol/L (normal 8–30). The diagnosis of thiamine deficiency was made, and the patient’s vision and neurologic symptoms improved significantly with intramuscular thiamine treatment. Thiamine deficiency can occur in the absence of an obvious predisposing factor such as alcoholism or low body weight. The clinician must be aware of the factors that govern vitamin availability and maintain a high index of suspicion to make the diagnosis in such cases. PMID:24899800

  13. Cell swelling, co-transport activation and potassium conductance in isolated perfused rabbit kidney proximal tubules.

    PubMed Central

    Beck, J S; Potts, D J

    1990-01-01

    1. Isolated, perfused rabbit proximal tubules were used to study the effects of activation of the apical membrane sodium co-transporters, and of the effects of osmotically induced cell swelling, upon cell volume, basolateral membrane potential and apparent partial conductance of potassium. 2. Activation of electrogenic apical sodium co-transport caused a depolarization of the basolateral membrane and a reduction of the basolateral apparent potassium transference number. This was followed by a spontaneous partial recovery of potential and increase in apparent potassium transference number. 3. Stimulation of apical sodium co-transport led to a sustained increase in cell volume. 4. A sustained increase in cell volume (of similar magnitude to that seen after activation of apical membrane sodium co-transporters) was also caused by reduction of bath and perfusate osmolality by removal of 89 mmol l-1 mannitol from both lumen and bath solutions. 5. This reduction in bath and perfusate osmolality also led to a basolateral membrane hyperpolarization and an increase in basolateral apparent potassium transference number. 6. These observations support the possibility that some of the partial recovery of basolateral membrane potential (Vb1) during apical sodium co-transport stimulation is due to a cell volume sensitive change in basolateral potassium conductance. PMID:2213582

  14. An analytical approach to the characterization of swelling in clay-bearing stone

    NASA Astrophysics Data System (ADS)

    Moonen, P.; Wangler, T.

    2015-10-01

    Clay minerals that swell when exposed to water play an important role in the deterioration of buildings and monuments, as well as in a number of civil engineering problems. A novel method for the in situ determination of the key properties governing these phenomena has been recently proposed by Scherer and Gonzalez [Geol. Soc. Am. Spec. Pap. 390 (2005) p.51]. A comprehensive relation between the experimental observations and the material properties could however not be established up to now. The present study develops an analytical model in which the interplay between geometrical factors and material properties, as well as initial and boundary conditions is accounted for. An extensive parametric study reveals that the discrepancies between the observations and the modelling approach by Scherer and Gonzalez is due to initial and boundary conditions on the one hand and the dispersion of the moisture front on the other hand. Based on the developed model, recommendations for performing in situ tests are formulated and conditions for the applicability of the more simplified modelling strategy by Scherer and Gonzalez are derived. A comparison with experimental data supports these conclusions.

  15. Organic brain syndrome

    MedlinePlus

    ... the skull causing pressure on brain ( subdural hematoma ) Concussion BREATHING CONDITIONS Low oxygen in the body (hypoxia) ... disease Arrhythmias Chronic subdural hematoma CO2 blood test Concussion Confusion Creutzfeldt-Jakob disease Dementia due to metabolic ...

  16. Fine needle aspiration cytology in isolated thyroid swellings: a prospective two year evaluation.

    PubMed Central

    Al-Sayer, H M; Krukowski, Z H; Williams, V M; Matheson, N A

    1985-01-01

    During 1 September 1981 to August 1982 aspiration cytology was carried out in all isolated thyroid swellings referred to the Aberdeen Thyroid Clinic: cytological findings were not disclosed, did not influence management, and were compared retrospectively with the histological diagnosis. In a total of 70 swellings sensitivity for the detection of neoplasia was 86% and overall accuracy 92%; the positive predictive value was 80% and negative predictive value 96%. During the second year (1 September 1982 to 31 August 1983), when cytological findings were used to influence management, the frequency of operation for isolated thyroid swellings decreased by 25% and the proportion of operations for neoplasia increased from 31% to 50%. In terms of bed occupancy the potentially avoidable surgical workload for benign disease was reduced by 34%. Aspiration cytology, carried out at the first clinic attendance, makes a sound basis for selective surgery and leads to economy in the management of isolated thyroid swellings. PMID:3922546

  17. 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.

  18. 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

  19. 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.

  20. Effects of granule swelling on starch saccharification by granular starch hydrolyzing enzyme.

    PubMed

    Li, Zhaofeng; Cai, Liming; Gu, Zhengbiao; Shi, Yong-Cheng

    2014-08-13

    The effects of granule swelling on enzymatic saccharification of normal corn starch by granular starch hydrolyzing enzyme were investigated. After swelling, Km values for the saccharification of granular starch decreased compared with native granular starch, indicating that granule swelling caused granular starch hydrolyzing enzyme to have higher affinity for starch granules. The partial swelling of starch granules enhanced starch saccharification. Furthermore, the enhancement at an earlier stage of enzymatic reaction was much more significant than that at later stages. For granular starch pretreated at 67.5 °C for 30 min, conversions to glucose after incubation with the enzyme at 32 °C for 4 and 24 h were approximately 3-fold and 26% higher than for native granular starch, respectively. As a result, proper heat pretreatment of granular starch before simultaneous saccharification and fermentation has great potential to facilitate industrial production of ethanol by use of granular starch hydrolyzing enzyme.

  1. 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.

  2. Partial Interruption of Axonal Transport Due to Microtubule Breakage Accounts for the Formation of Periodic Varicosities after Traumatic Axonal Injury

    PubMed Central

    Tang-Schomer, Min D.; Johnson, Victoria E.; Baas, Peter W.; Stewart, William; Smith, Douglas H.

    2012-01-01

    Due to their viscoelastic nature, white matter axons are susceptible to damage by high strain rates produced during traumatic brain injury (TBI). Indeed, diffuse axonal injury (DAI) is one of the most common features of TBI, characterized by the hallmark pathological profiles of axonal bulbs at disconnected terminal ends of axons and periodic swellings along axons, known as “varicosities.” Although transport interruption underlies axonal bulb formation, it is unclear how varicosities arise, with multiple sites accumulating transported materials along one axon. Recently, axonal microtubules have been found to physically break during dynamic stretch-injury of cortical axons in vitro. Here, the same in vitro model was used in parallel with histopathological analyses of human brains acquired acutely following TBI to examine the potential role of mechanical microtubule damage in varicosity formation post-trauma. Transmission electron microscopy (TEM) following in vitro stretch-injury revealed periodic breaks of individual microtubules along axons that regionally corresponded with undulations in axon morphology. However, typically less than a third of microtubules were broken in any region of an axon. Within hours, these sites of microtubule breaks evolved into periodic swellings. This suggests axonal transport may be halted along one broken microtubule, yet can proceed through the same region via other intact microtubules. Similar axonal undulations and varicosities were observed following TBI in humans, suggesting primary microtubule failure may also be a feature of DAI. These data indicate a novel mechanism of mechanical microtubule damage leading to partial transport interruption and varicosity formation in traumatic axonal injury. PMID:22079153

  3. Real-time imaging of exocytotic mucin release and swelling in Calu-3 cells using acridine orange.

    PubMed

    Shumilov, Dmytro; Popov, Alexander; Fudala, Rafal; Akopova, Irina; Gryczynski, Ignacy; Borejdo, Julian; Gryczynski, Zygmunt; Grygorczyk, Ryszard

    2014-03-15

    Mucus secretion is the first-line of defence against the barrage of irritants inhaled into human lungs, but abnormally thick and viscous mucus results in many respiratory diseases. Understanding the processes underlying mucus pathology is hampered, in part, by lack of appropriate experimental tools for labeling and studying mucin granule secretion from live cells with high sensitivity and temporal resolution. In this report we present original spectroscopic properties of acridine orange (AO) which could be utilized to study granule release and mucin swelling with various advanced fluorescence imaging approaches. Low concentration (<200 μM) AO solutions presented absorption maximum at 494 nm, emission maximum at 525 nm and only ∼1.76 ns fluorescence lifetime. By contrast at high concentrations (4-30 mM) favoring formation of AO aggregates, a very different absorption with maximum at ∼440 nm, dramatically red-shifted emission with maximum at 630 nm, and over 10-fold increased fluorescence lifetime (∼20 ns) was observed. To verify potential utility of AO for real-time imaging we have performed confocal, total internal reflection fluorescence (TIRF) and fluorescence lifetime imaging (FLIM) of AO-stained Calu-3 cells. We found similar red-shifted fluorescence spectra and long fluorescence lifetime in intracellular granules as compared to that in the cytoplasm consistent with granular AO accumulation. Mechanical stimulation of Calu-3 cells resulted in multiple exocytotic secretory events of AO-stained granules followed by post-exocytotic swelling of their fluorescently-labeled content that was seen in single-line TIRF images as rapidly-expanding bright-fluorescence patches. The rate of their size expansion followed first-order kinetics with diffusivity of 3.98±0.07×10(-7)c m(2)/s, as expected for mucus gel swelling. This was followed by fluorescence decrease due to diffusional loss of AO that was ∼10-fold slower in the secreted mucus compared to bulk aqueous

  4. An Investigation of the Irradiation Swelling Mechanisms in Refractory Metals at High Temperatures

    DTIC Science & Technology

    1989-06-01

    studied extensively since the 5 first discovery of voids in stainless steel , and also on the available swelling information for refractory metals and...Development of a Theoretical Model for Refractory Metals Since the discovery of voids in irradiated stainless steel by Cawthorne and Fulton (4 3 ) in 1967...damage structure and the observed swelling resistance in FV 448 3 martensitic stainless steel . After neutron irradiation to damage levels of 30

  5. 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%.

  6. Radiation synthesis of poly(2-vinylpyridine) gels and their swelling characteristics

    NASA Astrophysics Data System (ADS)

    Acar, N.

    2002-02-01

    The effect of irradiation under vacuum on thermal properties, and swelling behaviour on Poly(2-vinylpyridine) (P2VP) has been investigated with respect to their swelling properties and network structures. The gel percent of the irradiated P2VP samples was determined by Soxhlet extraction, and UV spectroscopy was used to determine sol percent. The change in glass transition temperature ( Tg) was followed by Differential Scanning Calorimetry before and after soxhlet extraction.

  7. Calculation of the evolution of the fuel microstructure in UMo alloys and implications for fuel swelling.

    SciTech Connect

    Rest, J.; Hofman, G. L.; Konovalov, I.; Maslov, A.

    1999-10-01

    The evolution of a cellular dislocation structure and subsequent recrystallization have been identified as important aspects of the irradiated UMo alloy microstructure that can have a strong impact on dispersion fuel swelling. Dislocation kinetics depends on the preferential bias of dislocations for interstitial compared to vacancies. This paper presents theoretical calculations for the evolution of a cellular dislocation structure, and recrystallization in U-10Mo. Implications for fuel swelling are discussed.

  8. Multicomponent, Multiphase Thermodynamics of Swelling Porous Media With Electroquasistatics. 1. Macroscale Field Equations

    DTIC Science & Technology

    2001-08-08

    entropy inequality with independent variables consistent with several natural systems and apply the resulting constitutive theory near equi- librium...1973. [3] L. S. Bennethum and J. H. Cushman. Multiscale , hybrid mixture theory for swelling systems - I: Balance laws. International Journal of...Engineering Science, 34(2):125–145, 1996. [4] L. S. Bennethum and J. H. Cushman. Multiscale , hybrid mixture theory for swelling systems - II: Constitutive

  9. An Experimental Investigation of Swelling and Elastic Property Changes Resulting from Carbon Dioxide Injection into Prismatic Coal Specimens

    NASA Astrophysics Data System (ADS)

    Dlamini, Bongani

    sample, where corresponding transducers on the other end of the sample receive the signal. Pre-injection measurements of sonic velocity (Vp and Vs) were taken. From sonic velocities (Vp and Vs), other pre-injection properties such as Poisson’s Ratio, shear, bulk and Young’s modulus (dynamic) were calculated. Digital deformation gauges were also strategically placed on the samples to measure strain (swelling) during the injection phase. CO2 was injected into the first sample at high confining pressure and high injection pressure. Injection proceeded for five days for each of the samples (25 hours of actual injection). A maximum increase in compressional velocity of 21% was measured at 12 MPa confining pressure and 4 MPa injection pressure. Increases in elastic moduli were also observed due to CO2 injection. A maximum adsorption strain (swelling) of 0.9% was measured at 12 MPa confining pressure and 4 MPa injection pressure. At high injection pressure (4 MPa) and high confining pressure (12 MPa), the coal started to swell at 5 hours of injection. At low injection pressure (1.8MPa) and low confining pressure (1.8MPa), the coal only started to swell at 10 hours of injection.

  10. 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

  11. A novel thermal swelling model for a rechargeable lithium-ion battery cell

    NASA Astrophysics Data System (ADS)

    Oh, Ki-Yong; Epureanu, Bogdan I.

    2016-01-01

    The thermal swelling of rechargeable lithium-ion battery cells is investigated as a function of the charge state and the charge/discharge rate. The thermal swelling shows significant dependency on the state of charge and the charge rate. The thermal swelling follows a quadratic form at low temperatures, and shows linear characteristics with respect to temperature at high temperatures in free-swelling conditions. Moreover, the equivalent coefficient of thermal expansion is much larger than that of each electrode and host materials, suggesting that the separator and the complex shape of the cell play a critical role in thermal expansion. Based on the experimental characterization, a novel thermal swelling model is proposed. The model introduces an equivalent coefficient of thermal expansion for the cell and also considers the temperature distribution throughout the battery by using heat transfer theory. The comparison between the proposed model and experiments demonstrates that the model accurately predicts thermal swelling at a variety of charge/discharge rates during operation and relaxation periods. The model is relatively simple yet very accurate. Hence, it can be useful for battery management applied to prolong the cycle life of cells and packs.

  12. Physical indicators of cartilage health: the relevance of compliance, thickness, swelling and fibrillar texture.

    PubMed

    Broom, Neil D; Flachsmann, René

    2003-06-01

    This study uses a bovine patella model to compare the relative merits of on-bone compliance and thickness measurements, free-swelling behaviour, and structural imaging with differential interference contrast (DIC) light microscopy to assess the biomechanical normality of the cartilage matrix. The results demonstrate that across a spectrum of cartilage tissues from immature, mature, through to mildly degenerate, and all with intact articular surfaces, there is a consistent pattern of increased free swelling of the isolated general matrix with age and degeneration. High swelling was always associated with major structural alterations of the general matrix that were readily imaged using DIC light microscopy. Conversely, for all tissue groups, no relationship was observed between thickness vs. compliance and compliance vs. general matrix swelling. Only in the proximal aspects of the normal mature and degenerate tissues was there a correlation between thickness and general matrix swelling. Free-swelling measurements combined with fibrillar texture imaging using DIC light microscopy are therefore recommended as providing a reliable and quick method of assessing the biomechanical condition of the cartilage general matrix.

  13. Hygroscopic Swelling Determination of Cellulose Nanocrystal (CNC) Films by Polarized Light Microscopy Digital Image Correlation.

    PubMed

    Shrestha, Shikha; Diaz, Jairo A; Ghanbari, Siavash; Youngblood, Jeffrey P

    2017-04-11

    The coefficient of hygroscopic swelling (CHS) of self-organized and shear-oriented cellulose nanocrystal (CNC) films was determined by capturing hygroscopic strains produced as result of isothermal water vapor intake in equilibrium. Contrast enhanced microscopy digital image correlation enabled the characterization of dimensional changes induced by the hygroscopic swelling of the films. The distinct microstructure and birefringence of CNC films served in exploring the in-plane hygroscopic swelling at relative humidity values ranging from 0% to 97%. Water vapor intake in CNC films was measured using dynamic vapor sorption (DVS) at constant temperature. The obtained experimental moisture sorption and kinetic profiles were analyzed by fitting with Guggenheim, Anderson, and deBoer (GAB) and Parallel Exponential Kinetics (PEK) models, respectively. Self-organized CNC films showed isotropic swelling, CHS ∼0.040 %strain/%C. By contrast, shear-oriented CNC films exhibited an anisotropic swelling, resulting in CHS ∼0.02 and ∼0.30 %strain/%C, parallel and perpendicular to CNC alignment, respectively. Finite element analysis (FEA) further predicted moisture diffusion as the predominant mechanism for swelling of CNC films.

  14. Local versus global mechanical effects of intramural swelling in carotid arteries.

    PubMed

    Sorrentino, T A; Fourman, L; Ferruzzi, J; Miller, K S; Humphrey, J D; Roccabianca, S

    2015-04-01

    Glycosaminoglycans (GAGs) are increasingly thought to play important roles in arterial mechanics and mechanobiology. We recently suggested that these highly negatively charged molecules, well known for their important contributions to cartilage mechanics, can pressurize intralamellar units in elastic arteries via a localized swelling process and thereby impact both smooth muscle mechanosensing and structural integrity. In this paper, we report osmotic loading experiments on murine common carotid arteries that revealed different degrees and extents of transmural swelling. Overall geometry changed significantly with exposure to hypo-osmotic solutions, as expected, yet mean pressure-outer diameter behaviors remained largely the same. Histological analyses revealed further that the swelling was not always distributed uniformly despite being confined primarily to the media. This unexpected finding guided a theoretical study of effects of different distributions of swelling on the wall stress. Results suggested that intramural swelling can introduce highly localized changes in the wall mechanics that could induce differential mechanobiological responses across the wall. There is, therefore, a need to focus on local, not global, mechanics when examining issues such as swelling-induced mechanosensing.

  15. Reliability and validity of measurements of facial swelling with a stereophotogrammetry optical three-dimensional scanner.

    PubMed

    van der Meer, Wicher J; Dijkstra, Pieter U; Visser, Anita; Vissink, Arjan; Ren, Yijin

    2014-12-01

    Volume changes in facial morphology can be assessed using the 3dMD DSP400 stereo-optical 3-dimensional scanner, which uses visible light and has a short scanning time. Its reliability and validity have not to our knowledge been investigated for the assessment of facial swelling. Our aim therefore was to assess them for measuring changes in facial contour, in vivo and in vitro. Twenty-four healthy volunteers with and without an artificial swelling of the cheek were scanned, twice in the morning and twice in the afternoon (in vivo measurements). A mannequin head was scanned 4 times with and without various externally applied artificial swellings (in vitro measurements). The changes in facial contour caused by the artificial swelling were measured as the change in volume of the cheek (with and without artificial swelling in place) using 3dMD Vultus software. In vivo and in vitro reliability expressed in intraclass correlations were 0.89 and 0.99, respectively. In vivo and in vitro repeatability coefficients were 5.9 and 1.3 ml, respectively. The scanner underestimated the volume by 1.2 ml (95% CI -0.9 to 3.4) in vivo and 0.2 ml (95% CI 0.02 to 0.4) in vitro. The 3dMD stereophotogrammetry scanner is a valid and reliable tool to measure volumetric changes in facial contour of more than 5.9 ml and for the assessment of facial swelling.

  16. Swelling of 316 stainless steel and D9 cladding in FFTF (Fast Flux Test Facility)

    SciTech Connect

    Makenas, B.J.

    1986-02-01

    A data base of cladding swelling measurements from postirradiation examinations of FFTF 316 stainless steel clad fuel pins has been developed which is now sufficiently large to compare to previously published cladding swelling data. This comparison of data was motivated by the observation, in the early cycles of FFTF operation, that design swelling correlations had to be adjusted to account for the observed length increases of driver assembly ducts. These original correlations had been developed from nonfueled EBR-II irradiation tests. The recent data indicate that FFTF and EBR-II cladding, from actual fuel pins with similar heats of steel, behave almost identically with respect to fast fluence. The FFTF data further suggest that, above approx.490/sup 0/C, 316 stainless steel (SS) swells in a manner which is essentially independent of irradiation temperature. A comparison of immersion density measurements with the length increases for FFTF driver fuel pins has also shown the 316 SS cladding swelling behavior to be essentially isotropic. D9 cladding (a titanium modified variant of 316 SS) has also been irradiated in FFTF. The data base here is limited, but is large enough to establish the superiority of D9 over 316 SS as an FFTF fuel pin cladding from a swelling point of view.

  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. Remarkable swelling capability of amino acid based cross-linked polymer networks in organic and aqueous medium.

    PubMed

    Roy, Saswati Ghosh; Haldar, Ujjal; De, Priyadarsi

    2014-03-26

    This work reports design and synthesis of side chain amino acid based cross-linked polymeric gels, able to switch over from organogel to hydrogel by a simple deprotection reaction and showing superabsorbancy in water. Amino acid based methacrylate monomers, tert-butoxycarbonyl (Boc)-l/d-alanine methacryloyloxyethyl ester (Boc-l/d-Ala-HEMA), have been polymerized in the presence of a cross-linker via conventional free radical polymerization (FRP) and the reversible addition-fragmentation chain transfer (RAFT) technique for the synthesis of cross-linked polymer gels. The swelling behaviors of these organogels are investigated in organic solvents, and they behave as superabsorbent materials for organic solvents such as dichloromethane, acetone, tetrahydrofuran, etc. Swollen cross-linked polymer gels release the absorbed organic solvent rapidly. After Boc group deprotection from the pendant alanine moiety, the organogels transform to the hydrogels due to the formation of side chain ammonium (-NH3(+)) groups, and these hydrogels showed a significantly high swelling ratio (∼560 times than their dry volumes) in water. The morphology of organogels and hydrogels is studied by field emission scanning electron microscopy (FE-SEM). Amino acid based cross-linked gels could find applications as absorbents for oil spilled on water as well as superabsorbent hydrogels.

  19. 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 ...

  20. Hypotonic hyponatremia by primary polydipsia caused brain death in a 10-year-old boy

    PubMed Central

    Ko, A Ra; Kim, Soo Jung; Jung, Mo Kyung; Kim, Ki Eun; Chae, Hyun Wook; Kim, Duk Hee; Kim, Ho-Seong

    2015-01-01

    Hypotonic hyponatremia by primary polydipsia can cause severe neurologic complications due to cerebral edema. A 10-year-and-4-month-old boy with a psychiatric history of intellectual disability and behavioral disorders who presented with chief complaints of seizure and mental change showed severe hypotonic hyponatremia with low urine osmolality (serum sodium, 101 mmol/L; serum osmolality, 215 mOsm/kg; urine osmolality, 108 mOsm/kg). The patient had been polydipsic for a few months prior, and this had been worse in the previous few days. A diagnosis of hypotonic hyponatremia caused by primary polydipsia was made. The patient was in a coma, and developed respiratory arrest and became brain death shortly after admission, despite the treatment. The initial brain magnetic resonance imaging showed severe brain swelling with tonsillar and uncal herniation, and the patient was declared as brain death. It has been reported that antidiuretic hormone suppression is inadequate in patients with chronic polydipsia, and that this inadequate suppression of antidiuretic hormone is aggravated in patients with acute psychosis. Therefore, hyponatremia by primary polydipsia, although it is rare, can cause serious and life-threatening neurologic complications. PMID:26512354

  1. Quantitative Mapping of Trimethyltin Injury in the Rat Brain Using Magnetic Resonance Histology

    PubMed Central

    Johnson, G. Allan; Calabrese, Evan; Little, Peter B.; Hedlund, Laurence; Qi, Yi; Badea, Alexandra

    2014-01-01

    The growing exposure to chemicals in our environment and the increasing concern over their impact on health have elevated the need for new methods for surveying the detrimental effects of these compounds. Today’s gold standard for assessing the effects of toxicants on the brain is based on hematoxylin and eosin (H&E)-stained histology, sometimes accompanied by special stains or immunohistochemistry for neural processes and myelin. This approach is time-consuming and is usually limited to a fraction of the total brain volume. We demonstrate that magnetic resonance histology (MRH) can be used for quantitatively assessing the effects of central nervous system toxicants in rat models. We show that subtle and sparse changes to brain structure can be detected using magnetic resonance histology, and correspond to some of the locations in which lesions are found by traditional pathological examination. We report for the first time diffusion tensor image-based detection of changes in white matter regions, including fimbria and corpus callosum, in the brains of rats exposed to 8 mg/Kg and 12 mg/Kg trimethyltin. Besides detecting brain-wide changes, magnetic resonance histology provides a quantitative assessment of dose-dependent effects. These effects can be found in different magnetic resonance contrast mechanisms, providing multivariate biomarkers for the same spatial location. In this study, deformation-based morphometry detected areas where previous studies have detected cell loss, while voxel-wise analyses of diffusion tensor parameters revealed microstructural changes due to such things as cellular swelling, apoptosis, and inflammation. Magnetic resonance histology brings a valuable addition to pathology with the ability to generate brain-wide quantitative parametric maps for markers of toxic insults in the rodent brain. PMID:24631313

  2. Controversies in the Management of Traumatic Brain Injury.

    PubMed

    Jinadasa, Sayuri; Boone, M Dustin

    2016-09-01

    Traumatic brain injury (TBI) is a physical insult (a bump, jolt, or blow) to the brain that results in temporary or permanent impairment of normal brain function. TBI describes a heterogeneous group of disorders. The resulting secondary injury, namely brain swelling and its sequelae, is the reason why patients with these vastly different initial insults are homogenously treated. Much of the evidence for the management of TBI is poor or conflicting, and thus definitive guidelines are largely unavailable for clinicians at this time. A substantial portion of this article focuses on discussing the controversies in the management of TBI.

  3. Response of PWR Baffle-Former Bolt Loading to Swelling, Irradiation Creep and Bolt Replacement as Revealed Using Finite Element Modeling

    SciTech Connect

    Simonen, Edward P.; Garner, Francis A.; Klymyshyn, Nicholas A.; Toloczko, Mychailo B.

    2005-10-01

    Baffle-former bolts in pressurized water reactors (PWRs) tend to degrade with aging, partially due to radiation-induced hardening and also due to the often complex stress history of the bolt in response to time-dependent and spatial gradients in temperature and neutron flux-spectra that can alter the stress distribution of the bolts. The time-integrated stresses must play some role in bolt cracking, however, and therefore it is of interest to study the time dependence of bolt stresses even for idealized cases. These stresses have been quantified in the present analysis using newly developed material constitutive equations for swelling and creep at light-water reactor (LWR)-relevant temperatures and dose rates. ABAQUS finite element calculations demonstrate that irradiation creep in the absence of void swelling tends to relax bolt tension before 10 dpa. Subsequent differential swelling leads to an increase in bolt tension, but only to stresses below the yield strength and usually below the initial bolt loading. Various assumed bolt replacement scenarios are considered with respect to their consequences on future failure possibilities.

  4. 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 ...

  5. 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, ...

  6. Brain components

    MedlinePlus Videos and Cool Tools

    The brain is composed of more than a thousand billion neurons. Specific groups of them, working in concert, provide ... of information. The 3 major components of the brain are the cerebrum, cerebellum, and brain stem. The ...

  7. 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.

  8. Integrated hydrogeological and geochemical processes in swelling clay-sulfate rocks

    NASA Astrophysics Data System (ADS)

    Schweizer, Daniel; Butscher, Christoph; Blum, Philipp

    2015-04-01

    The swelling of clay-sulfate rocks is a well-known problem in tunnel engineering where it poses a severe threat to important infrastructure. However, recently it was also encountered in an entirely different setting: The inaccurate implementation of geothermal installations in the town Staufen, Germany, led to water inflow into clay-sulfate rocks, resulting in heavy swelling. The swelling caused uplift rates of the ground surface exceeding 1 cm month-1, and severely damaged over 250 houses. The underlying processes of clay-sulfate rock swelling are complex and not yet sufficiently understood. In particular, hydraulic and geochemical processes in the zone of swelling are difficult to assess and the additional impact of constructional measures, such as borehole drilling, remains mostly unknown. The transformation of anhydrite into gypsum as a result of water influx is considered to be the main mechanism contributing to the swelling process, leading to an increase in volume of up to 60 %. This transformation process is decoupled: Anhydrite is dissolved and the pore-water concentration of sulfate increases; the dissolved sulfate may be transported with groundwater flow and finally precipitates as gypsum. Hence, groundwater flow and geochemistry of the pore-water play an essential role in the swelling processes. In fact, the swelling of clay-sulfate rocks is likely initiated by a change in geochemistry brought about by a change in hydraulic conditions. Thus, the main objective of this project is to quantify groundwater flux and geochemical reactions within swelling zones influenced by engineering activities, such as geothermal drillings. Additionally, reaction rates of anhydrite dissolution and gypsum precipitation at the field scale are to be compared with reaction rates determined in laboratory experiments. This study investigates the significance of (1) the local geological setting, (2) hydrology and geochemistry of the swelling zone and (3) their modification upon

  9. [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.

  10. Swelling-Induced Folding in Confined Nanoscale Responsive Polymer Gels

    DTIC Science & Technology

    2010-03-16

    is a weak cat- ionic polymer that exhibits dramatic globulecoil transformation due to the protonation of the pyridine group below pH 4.0.5456 As a...on the pyridine ring.57 In the protonated state (below pH 4.0), the electrostatic in- teraction between the positively charged pyridine units and...re- moves hydrogen bonding and introduces Coulombic repulsion between protonated pyridine groups and the substrate. For this control system with

  11. Perineal swelling, intermenstrual cycle, and female sexual behavior in bonobos (Pan paniscus).

    PubMed

    Paoli, T; Palagi, E; Tacconi, G; Tarli, S Borgognini

    2006-04-01

    Many reports have claimed that the duration of the swelling cycle in female bonobos (Pan paniscus) is longer than that of chimpanzees, and that the bonobo maximum swelling phase is markedly prolonged. Field data on intermenstrual intervals (IMIs) in female bonobos are limited and restricted to interswelling intervals (ISIs), which are assumed to reflect the IMI, though a direct comparison between the duration of ISIs and IMIs is still lacking. Reports on bonobo sexual activity as a function of the swelling phase are often contradictory. Moreover, the function of female homosexual interactions (genito-genital (GG) rubbing) is still debated. This study examines the reliability of the ISI as an approximation of the IMI, and the attractivity of female sexual swellings for other individuals. An analysis of 51 ISI-IMI pairs showed that ISIs are a fair representation of the reproductive cycle. The cycle length was 35.6+/-1.1 SE days relying on the ISI, whereas it was 35.0+/-1.1 SE days considering the IMI. This result is similar to the cycle length reported for chimpanzees. Female homosexual interactions and copulatory rates were higher during maximum tumescence, suggesting that the sexual swelling may be attractive for both males and other females. Furthermore, the GG-rubbing was performed free of a hierarchical postural imposition, and was not correlated with affinitive interactions. We suggest that GG-rubbing, which is generally the most frequent female sexual interaction, is a tool for social assessments among females.

  12. Utility of ultrasonography for diagnosis of superficial swellings in buffalo (Bubalus bubalis)

    PubMed Central

    ABOUELNASR, Khaled; EL-SHAFAEY, El-Sayed; MOSBAH, Esam; EL-KHODERY, Sabry

    2016-01-01

    We studied 72 buffalo with superficial swellings in the head (n=4), neck (n=5), chest wall (n=4), abdominal wall (n=28), limbs (n=16), gluteal region (n=8), perineal region (n=6) and udder (n=1). Ultrasonographically, the swellings varied according to type, duration, content and location. The clinical use of ultrasound to assess these superficial swellings allowed diagnosis of abscesses (n=21), hematomas (n=11), hernias (n=17), bursitis (n=13), urethral diverticula (n=6) and tumors (n=4). Ultrasonography could precisely discriminate each lesion type (sensitivity, 71–100%; specificity, 75–100%; odds ratio, 1.0–8.4; Confidence Interval, 74.2–20; and P value 0.001). The specificity for ultrasonographic evaluation of superficial swellings was 100% for hernias, urethral diverticula and tumors, whilst the lowest specificity was recorded for hematomas (75%) and abscesses (92%). In conclusion, ultrasonography provides a precise, non-invasive and fast technique for the evaluation, classification and subsequent treatment of a variety of superficial swellings in buffalo. PMID:27181085

  13. Aqueous thiocyanate-urea solution as a powerful non-alkaline swelling agent for cellulose fibres.

    PubMed

    Mahmud-Ali, Amalid; Bechtold, Thomas

    2015-02-13

    For many applications cellulose fibres are treated with concentrated solutions of swelling agents to increase reactivity and to achieve reorganisation of fibre structure. Representative examples are caustic soda, potassium hydroxide solution or liquid ammonia. These highly concentrated media bear considerable safety hazards during the technical handling thus alternative swelling agents are of interest. The thiocyanate-urea system investigated in this work offers high swelling potential for regenerated cellulose fibres. Experiments with different cations of M(+) in M(+) SCN(-) demonstrate the significant influence of the cation on the degree of fibre swelling. In concentrated NaSCN/urea solutions, at 80 °C, lyocell fibres expand the diameter from 12-14 to 100 μm. The treatment in the swelling agent also led to a significant increase in the water retention value which was accompanied by a strength loss of 20-40% of the initial value. FTIR analysis of treated fibres did not indicate substantial changes in structure of the cellulose polymer. Limited weight loss of up to 20% was observed despite the high expansion of the fibre.

  14. Effectiveness of Submucosal Dexamethasone to Control Postoperative Pain & Swelling in Apicectomy of Maxillary Anterior Teeth

    PubMed Central

    Shah, Shahzad Ali; Khan, Irfanullah; Shah, Humera Shahzad

    2011-01-01

    Purpose The purpose of this study was to evaluate the effect of submucosal dexamethasone injection to control postoperative pain and swelling in apicectomy of maxillary anterior teeth. Methods A randomized, controlled trial comprising 60 adult patients (68.3% male, 31.7% female) with no local or systemic problems was conducted. Patients were randomly divided into two groups: Group A was given 4mg dexamethasone injection perioperatively. Group B (control group) was treated conventionally without any steroid injection. Postoperative pain and swelling was evaluated using a visual analog scale (VAS). Objective measurements of facial pain and swelling were performed daily up to six days postoperatively. Results Dexamethasone group showed significant reduction in pain and swelling postoperatively compared with the control. Conclusion Submucosal dexamethasone 4mg injection is an effective therapeutic strategy for swift and comfortable improvement after surgical procedure and has a significant effect on reducing postoperative pain and swelling. The treatment offers a simple, safe, painless, noninvasive and cost effective therapeutic option for moderate and severe cases. PMID:23267293

  15. Characterization and swelling-deswelling properties of wheat straw cellulose based semi-IPNs hydrogel.

    PubMed

    Liu, Jia; Li, Qian; Su, Yuan; Yue, Qinyan; Gao, Baoyu

    2014-07-17

    A novel wheat straw cellulose-g-poly(potassium acrylate)/polyvinyl alcohol (WSC-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) hydrogel was prepared by polymerizing wheat straw and an aqueous solution of acrylic acid (AA), and further semi-interpenetrating with PVA occurred during the chemosynthesis. The swelling and deswelling properties of WSC-g-PKA/PVA semi-IPNs hydrogel and WSC-g-PKA hydrogel were studied and compared in various pH solutions, salt solutions, temperatures, particle sizes and ionic strength. The results indicated that both hydrogels had the largest swelling capacity at pH=6, and the effect of ions on the swelling of hydrogels was in the order: Na(+)>K(+)>Mg(2+)>Ca(2+). The Schott's pseudo second order model can be effectively used to evaluate swelling kinetics of hydrogels. Moreover, the semi-IPNs hydrogel had improved swelling-deswelling properties compared with that of WSC-g-PKA hydrogel.

  16. Water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels

    NASA Astrophysics Data System (ADS)

    Wang, Qingguo; Zhou, Xue; Zeng, Jinxia; Wang, Jizeng

    2016-02-01

    In this paper, the electron beam irradiation technology being more suitable for the industry application is explored to fabricate the acrylic acid (AAc) monomer-grafted polyvinyl alcohol (PVA-g-AAc) hydrogels. ATR-IR spectra of the PVA-g-AAc hydrogels shows an obvious absorption peak of the sbnd Cdbnd O group at 1701 cm-1, indicating that the AAc monomers were grafted onto the PVA macromolecules. This paper also studied some effects of the mass ratio of PVA/AAc, pH of buffer solution and irradiation dosage on the water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels. The water swelling ratio of PVA-g-AAc hydrogels decreases with increased irradiation dosage and mass ratio of PVA/AAc, whereas swelling ratio increases with increased pH of buffer solution and soaking time. The water-swelling behavior of PVA-g-AAc hydrogels occurred easily in an alkaline environment, particularly in a buffer solution with pH 9.2. Both PVA-g-AAc hydrogels (PVA/AAc = 1/5, w/w) irradiated with 5 kilogray (kGy) and PVA-g-AAc hydrogels (PVA/AAc = 1/1, w/w) irradiated with 15 kGy could easily absorb water and lead to high water swelling ratios (up to about 600%), which are potential candidates to meet the requirements for some biomedical applications.

  17. Myosin light chain kinase and Src control membrane dynamics in volume recovery from cell swelling

    PubMed Central

    Barfod, Elisabeth T.; Moore, Ann L.; Van de Graaf, Benjamin G.; Lidofsky, Steven D.

    2011-01-01

     The expansion of the plasma membrane, which occurs during osmotic swelling of epithelia, must be retrieved for volume recovery, but the mechanisms are unknown. Here we have identified myosin light chain kinase (MLCK) as a regulator of membrane internalization in response to osmotic swelling in a model liver cell line. On hypotonic exposure, we found that there was time-dependent phosphorylation of the MLCK substrate myosin II regulatory light chain. At the sides of the cell, MLCK and myosin II localized to swelling-induced membrane blebs with actin just before retraction, and MLCK inhibition led to persistent blebbing and attenuated cell volume recovery. At the base of the cell, MLCK also localized to dynamic actin-coated rings and patches upon swelling, which were associated with uptake of the membrane marker FM4-64X, consistent with sites of membrane internalization. Hypotonic exposure evoked increased biochemical association of the cell volume regulator Src with MLCK and with the endocytosis regulators cortactin and dynamin, which colocalized within these structures. Inhibition of either Src or MLCK led to altered patch and ring lifetimes, consistent with the concept that Src and MLCK form a swelling-induced protein complex that regulates volume recovery through membrane turnover and compensatory endocytosis under osmotic stress. PMID:21209319

  18. Couplings between swelling and shear in saturated slit nanopores: a molecular simulation study.

    PubMed

    Hoang, Hai; Galliero, Guillaume

    2015-01-01

    In this article, the coupling between swelling and shear in liquid saturated slit nanopores is studied using molecular dynamics simulations on Lennard-Jones systems. First, the consistency of the simulations using thermodynamics and direct routes is validated when dealing separately with swelling and shear. Then, the coupling between swelling and shear is explored by displacing the solid walls in one direction while letting them move freely on the other. Results indicate that shear can induce swelling and vice versa because of the confined fluid phase structure. This phenomenon, which is neglected in poromechanics modeling, may be non-negligible in highly structured microporous systems, such as clays. It implies that the response to a variation in the external load can be a combination of volumetric and shear deformations, because of the fluid. Finally, we explore the behavior induced by solid walls moving at a constant velocity. Interestingly, when the wall velocity exceeds the swelling velocity, the instantaneous states of the system are no longer at equilibrium and the averaged pore width slightly increases with increasing shear rate.

  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. Ontogenetic aspects of traumatic brain edema--facts and suggestions.

    PubMed

    Bauer, R; Walter, B; Fritz, H; Zwiener, U

    1999-02-01

    Diffuse brain swelling (DBS) after severe traumatic brain injury (TBI) occurs more commonly in children than adults. Most of the recent clinical studies suggest that young children are more negatively affected by DBS. Until now studies in young animals in which the pathophysiology of DBS was evaluated remained seldom. However, pathogenetic mechanisms of edema formation after TBI in the immature brain appeared to be different in comparison to adult brains. There are evidences that vasogenic as well as cytotoxic edema components may be responsible for the development of DBS. Besides mechanical disturbance, the blood-brain barrier seems to be strongly endangered by oxidative stress after TBI because regional antioxidative capacity is obviously diminished. In addition, cytotoxic components of DBS may be caused by at least two different mechanisms. First, it was shown that a sustained posttraumatic cerebral hypoperfusion occurs in the immature brain. Moreover, a transient increase of NMDA receptor expression at this period of life may be responsible for an increased threat of intracellular sodium ion accumulation in brain cells. Obviously, brain swelling can be detrimental because it can elevate intracranial pressure, impair CBF, and may represent ongoing secondary brain injury.

  1. Swelling behavior of halthane 73-18 polyurethane adhesive in dimethyl sulfoxide (DMSO)

    SciTech Connect

    LeMay, J. D., LLNL

    1996-06-01

    To insure safe performance during the launch and flight of the W79 Artillery Fired Atomic Projectile (AFAP), the assembly gaps in the high explosive assembly were filled with a continuous film of polyurethane elastomer adhesive called Halthane 73-18. To disassemble bonded weapons like the W79, Lawrence Livermore and Mason & Hanger, Pantex Plant have developed a chemical dissolution process that safely removes the high explosive, thereby facilitating the recovery of the pit. The solvent of choice for the W79 AFAP was dimethyl sulfoxide (DMSO). In the W79 dissolution process, a continuous spray of DMSO is emitted through nozzles mounted in manifold assembly that encircles the HE assembly. The operating pressure and temperature of the DMSO are less than 100 psig and less than 160{degrees}F. Although warm DMSO readily dissolves the LX-10{sup 1} explosive, it cannot dissolve the Halthane 73-18 adhesive due to its chemically crosslinked structure. DMSO does, however, swell the Halthane adhesive. The resulting swollen films are soft and unable to support their own weight, yet they are not necessarily so fragile that they will tear or shred readily under the force of the DMSO spray. Indeed, the swollen Halthane films encountered in several W79 Type 6B 2048 units tested in the Pantex Workstation proved to be quite tenacious. They remained intact under the action of DMSO spray and became an encapsulating barrier that shielded the remaining undissolved HE. This effectively stopped the dissolution process, forcing manual removal in order to complete the dissolution process. By comparison, the swollen Halthane film was readily shredded and eliminated under the action of the DMSO spray nozzles in tests at LLNL in workstation of a different design. This apparent difference in response is the subject of this report.

  2. 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

  3. 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.

  4. 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

  5. Swelling of radiation crosslinked acrylamide-based microgels and their potential applications

    NASA Astrophysics Data System (ADS)

    Abd El-Rehim, H. A.

    2005-10-01

    Crosslinked polyacrylamide PAAm and acrylamide-Na-acrylate P(AAm-Na-AAc) microgels were prepared by electron beam irradiation. It was found that the dose required for crosslinking depends on the polymer moisture content, so that the dose to obtain PAAm of maximum gel fraction was over 40 and 20 kGy for dry and moist PAAm, respectively. The structural changes in irradiated PAAm were investigated using FTIR and SEM. The swelling property of such microgels in distilled water and real urine solution was determined and crosslinked polymers reached their equilibrium swelling state in a few minutes. As the gel content and crosslinking density decrease, the swelling of the microgels increases. The ability of the microgels to absorb and retain large amount of solutions suggested their possible uses in horticulture and in hygienic products such as disposable diapers.

  6. Irradiation swelling behavior and its dependence on temperature, dose rate and dislocation structure evolution

    SciTech Connect

    Surh, M P; Sturgeon, J B; Wolfer, W G

    2004-01-16

    The microstructural evolution of high purity steel under irradiation is modeled including a dislocation density that evolves simultaneously with void nucleation and growth. The predicted void swelling trends versus temperature, flux, and time are compared to experiment and to earlier calculations with a fixed dislocation density. The behavior is further analyzed within a simplified picture of segregation of irradiation defects to microstructural sinks. Agreement with experimental swelling behavior improves when dislocations co-evolve with the void content versus simulations with a fixed dislocation density. The time-dependent dislocation content dictates the rate of void nucleation and shapes the overall void size distribution so as to give steady swelling behavior over long times.

  7. Assessment of fission-gas-induced transient swelling in metallic fuel

    SciTech Connect

    Sevy, R H; Cahalan, J E

    1985-03-01

    A model for fission-gas-induced transient swelling in metallic fuel is described. An observation that the strength of metallic fuel becomes very small at a temperature several hundred degrees below the solidus forms the basis for an assumption that, above this temperature, the fuel proceeds through a series of stress-free equilibrium states for a large range of heating rates. Gas bubble coalescence and growth and any effects from ingested sodium are ignored such that the model may tend to underestimate swelling in some circumstances. The fuel swelling model is used to predict the reactivity effect of fission-gas-induced axial expansion of metallic fuel during transient overpower excursions. Comparisons to oxide fuel behavior are made. Sensitivity of results to metallic fuel modeling assumptions are assessed in a parametric study.

  8. Effect of doping swelling polymer cladding with phthalocyanine dye in plastic optical fiber humidity sensors

    NASA Astrophysics Data System (ADS)

    Morisawa, Masayuki; Yokomori, Haruyuki

    2011-05-01

    We have developed and tested plastic optical fiber (POF)-type humidity sensors, which consist of a dye-doped swelling polymer cladding. POF-type humidity sensors consist of a hydroxyethyl cellulose or polyvinylpyrrolidone (PVP) cladding layer that surrounds a poly(methyl methacrylate) core. The operation of these sensors is based on the change in refractive index caused by swelling of the cladding layer. To improve the sensitivity of the humidity sensor, we have investigated the effect of doping the cladding polymer with phthalocyanine dye. The results indicate that the POF-type humidity sensor using PVP is three times more sensitive for relative humidities above 80% when the dyedoped swelling-polymer cladding is used.

  9. Screening of Potential O-Ring Swelling Additives for Ultraclean Transportation Fuels

    SciTech Connect

    Baltrus, J.P.; Link, D.D.; Zandhuis, P.H.; Gormley, R.J.; Anderson, R.R.

    2007-03-01

    Several classes of organic compounds and mixtures of organic compounds were evaluated as potential additives to Fischer-Tropsch fuels to promote swelling of nitrile rubber o-rings that come in contact with the fuels. Computational modeling studies were also carried out to predict which compounds might be best at promoting o-ring swelling. The combined experimental-theoretical approach showed that steric factors strongly influence the interactions between additives and the nitrile sites in the rubber that result in swelling. Select compounds incorporating both oxygenate and aromatic functionalities appear to be the best candidates for additives because of a "dual" interaction between complementary functionalities on these compounds and the nitrile rubber.

  10. Geophysics and Nanosciences: Nano to Micro to Meso to Macro Scale Swelling Soils

    NASA Astrophysics Data System (ADS)

    Cushman, J.

    2003-04-01

    We use statistical mechanical simulations of nanoporous materials to motivate a choice of independent constitutive variables for a multiscale mixture theory of swelling soils. A video will illustrate the structural behavior of fluids in nanopores when they are adsorbed from a bulk phase vapor to form capillaries on the nanoscale. These simulations suggest that when a swelling soil is very dry, the full strain tensor for the liquid phase should be included in the list of independent variables in any mixture theory. We use this information to develop a three-scale (micro, meso, macro) mixture theory for swelling soils. For a simplified case, we present the underlying multiscale field equations and constitutive theory, solve the resultant well posed system numerically, and present some graphical results for a drying and shrinking body.

  11. Severe facial swelling in a pregnant woman after using hair dye.

    PubMed

    van Genderen, Michel E; Carels, Ginette; Lonnee, Edward R; Dees, Adriaan

    2014-03-31

    A 33-year-old Caucasian pregnant woman (26 weeks' gestation) presented to the emergency department. She had a 2-day history of severe itching of the scalp and steadily worsening swelling of the face over the previous 12 h, which had extended to the neck. She had no difficulty breathing. The itching and swelling had developed 3 days after she had used hair dye. The patient had no history of allergic responses to hair dye or black henna tattoos. A diagnosis of type IV delayed hypersensitivity reaction was made. Permanent hair dyes are the most frequently used professional hair dyes and are most commonly based on paraphenylenediamine (PPD) or related chemicals. PPD is known to be one of the most potent allergens which cause allergic contact dermatitis. After treatment with intravenous antihistamines and steroids, the facial swelling reduced and the patient had completely recovered by the following day.

  12. The Effect of Swelling Ratio on the Coulter Underestimation of Hydrogel Microsphere Diameters

    PubMed Central

    Pellegrini, Michael; Cherukupalli, Abhimanyu; Medini, Michael; Falkowski, Ron

    2015-01-01

    It has been demonstrated that the diameters of porous particles are underestimated by Coulter measurements. This phenomenon has also been observed in hydrogel particles, but not characterized. Since the Coulter principle uses the displacement of electrolyte to determine particle size, electrolyte contained within the swelled hydrogel microparticles results in an underestimate of actual particle diameters. The increased use of hydrogel microspheres in biomedical applications has led to the increased application of the Coulter principle to evaluate the size distribution of microparticles. A relationship between the swelling ratio of the particles and their reported Coulter diameters will permit calculation of the actual diameters of these particles. Using polyethylene glycol diacrylate hydrogel microspheres, we determined a correction factor that relates the polymer swelling ratio and the reported Coulter diameters to their actual size. PMID:26414785

  13. Swelling and morphology of the skin layer of polyamide composite membranes: an atomic force microscopy study.

    PubMed

    Freger, Viatcheslav

    2004-06-01

    The paper introduces a new methodology for studying polyamide composite membranes for reverse osmosis (RO) and nanofiltration (NF) in liquid environments. The methodology is based on atomic force microscopy of the active layer, which had been separated from the support and placed on a solid substrate. The approach was employed to determine the thickness, interfacial morphology, and dimensional changes in solution (swelling) of polyamide films. The face (active) and back (facing the support) surfaces of the RO films appeared morphologically similar, in agreement with the recently proposed model of skin formation. Measured thickness and swelling data in conjunction with the intrinsic permeability of the membranes suggest that the selective barrier in RO membrane constitutes only a fraction of the polyamide skin, whereas NF membranes behave as nearly uniform films. For NF membranes, there was reasonable correlation between the changes in the swelling and in the permeability of the membrane and the salinity and pH of the feed.

  14. NEUTRON-INDUCED SWELLING OF Fe-Cr BINARY ALLOYS IN FFTF AT ~400 DEGREES C

    SciTech Connect

    Garner, Francis A.; Greenwood, Lawrence R.; Okita, Taira; Sekimura, Naoto; Wolfer, W. G.

    2002-12-31

    The purpose of this effort is to determine the influence of dpa rate, He/dpa ratio and composition on the void swelling of simple binary Fe-Cr alloys. Contrary to the behavior of swelling of model fcc Fe-Cr-Ni alloys irradiated in the same FFTF-MOTA experiment, model bcc Fe-Cr alloys do not exhibit a dependence of swelling on dpa rate at approximately 400 degrees C. This is surprising in that an apparent flux-sensitivity was observed in an earlier comparative irradiation of Fe-Cr binaries conducted in EBR-II and FFTF. The difference in behavior is ascribed to the higher helium generation rates of Fe-Cr alloys in EBR-II compared to that of FFTF, and also the fact that lower dpa rates in FFTF are accompanied by progressively lower helium generation rates.

  15. Study on swelling behaviour of hydrogel based on acrylic acid and pectin from dragon fruit

    NASA Astrophysics Data System (ADS)

    Abdullah, Mohd Fadzlanor; Lazim, Azwani Mat

    2014-09-01

    Biocompatible hydrogel based on acrylic acid (AA) and pectin was synthesized using gamma irradiation technique. AA was grafted onto pectin backbone that was extracted from dragon fruit under pH 3.5 and extracts and ethanol ratios (ER) 1:0.5. The optimum hydrogel system with high swelling capacity was obtained by varying the dose of radiation and ratio of pectin:AA. FTIR-ATR spectroscopy was used to verify the interaction while thermal properties were analyzed by TGA and DSC. Swelling studies was carried out in aqueous solutions with different pH values as to determine the pH sensitivity. The results show that the hydrogel with a ratio of 2:3 (pectin:AA) and 30 kGy radiation dose has the highest swelling properties at pH of 10.

  16. Severe facial swelling in a pregnant woman after using hair dye

    PubMed Central

    van Genderen, Michel E; Carels, Ginette; Lonnee, Edward R; Dees, Adriaan

    2014-01-01

    A 33-year-old Caucasian pregnant woman (26 weeks’ gestation) presented to the emergency department. She had a 2-day history of severe itching of the scalp and steadily worsening swelling of the face over the previous 12 h, which had extended to the neck. She had no difficulty breathing. The itching and swelling had developed 3 days after she had used hair dye. The patient had no history of allergic responses to hair dye or black henna tattoos. A diagnosis of type IV delayed hypersensitivity reaction was made. Permanent hair dyes are the most frequently used professional hair dyes and are most commonly based on paraphenylenediamine (PPD) or related chemicals. PPD is known to be one of the most potent allergens which cause allergic contact dermatitis. After treatment with intravenous antihistamines and steroids, the facial swelling reduced and the patient had completely recovered by the following day. PMID:24686800

  17. Evaluation of an Acute RNAi-Mediated Therapeutic for Visual Dysfunction Associated with Traumatic Brain Injury

    DTIC Science & Technology

    2013-10-01

    water from the brain to the blood and significantly impacts on brain swelling. We also show cognitive improvement in mice with focal cerebral...brain injury ( TBI ) is the leading cause of death in children and young adults globally. Malignant cerebral edema plays a major role in the...pathophysiology which evolves after severe TBI . Added to this is the significant morbidity and mortality from cerebral edema associated with acute stroke

  18. Influence of sodium dodecyl sulfate on swelling, erosion and release behavior of HPMC matrix tablets containing a poorly water-soluble drug.

    PubMed

    Zeng, Aiguo; Yuan, Bingxiang; Fu, Qiang; Wang, Changhe; Zhao, Guilan

    2009-01-01

    The effect of sodium dodecyl sulfate (SDS) on the swelling, erosion and release behavior of HPMC matrix tablets was examined. Swelling and erosion of HPMC matrix tablets were determined by measuring the wet and subsequent dry weights of matrices. The rate of uptake of the dissolution medium by the matrix was quantified using a square root relationship whilst the erosion of the polymer was described using the cube root law. The extent of swelling decreased with increasing SDS concentrations in the dissolution medium but the rate of erosion was found to follow a reverse trend. Such phenomena might have been caused by the attractive hydrophobic interaction between HPMC and SDS as demonstrated by the cloud points of the solutions containing both the surfactant and polymer. Release profiles of nimodipine from HPMC tablets in aqueous media containing different concentrations of SDS were finally studied. Increasing SDS concentrations in the medium was shown to accelerate the release of nimodipine from the tablets, possibly due to increasing nimodipine solubility and increasing rate of erosion by increasing SDS concentrations in the dissolution medium.

  19. Purinergic receptor activation inhibits osmotic glial cell swelling in the diabetic rat retina.

    PubMed

    Wurm, Antje; Iandiev, Ianors; Hollborn, Margrit; Wiedemann, Peter; Reichenbach, Andreas; Zimmermann, Herbert; Bringmann, Andreas; Pannicke, Thomas

    2008-10-01

    The anti-inflammatory glucocorticoid, triamcinolone acetonide, is used clinically for the rapid resolution of diabetic macular edema. Osmotic swelling of glial cells may contribute to the development of retinal edema. Triamcinolone inhibits the swelling of retinal glial cells of diabetic rats. Here, we determined whether the effect of triamcinolone is mediated by a receptor-dependent mechanism. Hyperglycemia was induced in rats with streptozotocin injection. After 6-10 months, the swelling properties of glial cells in retinal slices upon hypotonic challenge were determined. Nucleotide-degrading ecto-enzymes were immunostained in retinal slices and glial cells. Hypotonic challenge did not change the size of glial cell bodies from control retinas but induced swelling of cells from diabetic animals. Triamcinolone inhibited glial cell swelling; this effect was prevented by a selective antagonist of adenosine A1 receptors, an inhibitor of nucleoside transporters, inhibitors of adenylyl cyclase and protein kinase A activation, and inhibitors of potassium and chloride channels. In diabetic (but not control) retinas, the effect of triamcinolone apparently involves extracellular nucleotide degradation. Glial cells from diabetic retinas displayed immunolabeling against nucleoside triphosphate diphosphohydrolase-1 (NTPDase1) which was not observed in control retinas. The mRNA expression for NTPDase1 was significantly increased in the retina of diabetic rats. It is suggested that triamcinolone induces the release and formation of endogenous adenosine that subsequently activates A1 receptors resulting in ion efflux through potassium and chloride channels and prevention of osmotic swelling. Whereas adenosine is liberated via facilitated transport in control retinas, an extracellular formation of adenosine contributes to the effect of triamcinolone in diabetic retinas.

  20. Relationship between swelling of hydroxypropylmethylcellulose and the Hansen and Karger partial solubility parameters.

    PubMed

    Navarro-Lupión, Francisco-Javier; Bustamante, Pilar; Escalera, Begoña

    2005-07-01

    A model that relates the equilibrium swelling of hydroxypropylmethylcellulose to the partial solubility parameters of both the polymer and the solvents is proposed to interpret and correlate the experimental data. The non-specific interactions are expressed as the dispersion delta(d) and polar delta(p) solubility parameters of Hansen, or as a combination of both. Hydrogen bonding is represented by the acidic delta(a) and the basic delta(b) Karger solubility parameters. The results are compared with models including the same parameters for non-specific interactions (delta(d) and delta(p)) and the Hansen hydrogen bonding parameter delta(h). Equilibrium swelling of this hydrophilic polymer that is widely used in drug formulation is measured in pure solvents covering a wide polarity range. In a qualitative way, swelling increases in solvents with higher Hildebrand solubility parameters and stronger hydrogen bonding capability, and it decreases in non-polar solvents. Single polarity indexes, such as the Hildebrand solubility parameter or the partition coefficient (PC), do not fit well the overall experimental data. The best correlations were obtained with the proposed model, providing at the same time an interpretation consistent with the physical meaning of the terms included in the equation. Swelling increases as the non-specific interactions of the polymer and the solvents become alike, and as the Lewis acid-base interactions of the polymer (1) and the solvent (2) represented by the products delta(1a)delta(2b) and delta(1b)delta(2a) become greater. Conversely, hydrogen bonding self association of the solvents (the product delta(1a)delta(1b)) lowers swelling. The results show that the Karger hydrogen bonding parameters provide a better approach than the Hansen hydrogen bonding parameter to correlate the swelling behavior of a hydrophilic polymer.

  1. In vitro measurement of nucleus pulposus swelling pressure: A new technique for studies of spinal adaptation to gravity

    NASA Technical Reports Server (NTRS)

    Hargens, A. R.; Glover, M. G.; Mahmood, M. M.; Gott, S.; Garfin, S. R.; Ballard, R.; Murthy, G.; Brown, M. D.

    1992-01-01

    Swelling of the intervertebral disc nucleus pulposus is altered by posture and gravity. We have designed and tested a new osmometer for in vitro determination of nucleus pulposus swelling pressure. The functional principle of the osmometer involves compressing a sample of nucleus pulposus with nitrogen gas until saline pressure gradients across a 0.45 microns Millipore filter are eliminated. Swelling pressure of both pooled dog and pooled pig lumbar disc nucleus pulposus were measured on the new osmometer and compared to swelling pressures determined using the equilibrium dialysis technique. The osmometer measured swelling pressures comparable to those obtained by the dialysis technique. This osmometer provides a rapid, direct, and accurate measurement of swelling pressure of the nucleus pulposus.

  2. Large Plunging Ranula Presenting as Isolated Neck Swelling: Steps in Diagnosis and Surgical Steps in Management

    PubMed Central

    Malik, Neelima A.; Patil, Pankaj; Chapi, Mouneshkumar Devendrappa

    2015-01-01

    Ranula is a salivary gland cyst which typically present as localized superficial swelling over the floor of mouth. Complex or plunging ranulas develop when the mucus extravasation extends through or around the mylohyoid muscle, deeper into the neck, and present with neck lump along with or without swelling over floor of mouth. We report a case of large plunging ranula presenting as an isolated large neck mass in a 38-year-old female patient. The steps in diagnosis and surgical steps in management of the pathology are systematically described. PMID:26266141

  3. Effect of initial oxygen content on the void swelling behavior of fast neutron irradiated copper

    SciTech Connect

    Zinkle, S.J.; Garner, F.A.

    1998-03-01

    Density measurements were performed on high purity copper specimens containing {le}10 wt.ppm and {approximately}120 wt.ppm oxygen following irradiation in FFTF MOTA 2B. Significant amounts of swelling were observed in both the oxygen-free and oxygen-doped specimens following irradiation to {approximately}17 dpa at 375 C and {approximately}47 dpa at 430 C. Oxygen doping up to 360 appm (90 wt.ppm) did not significantly affect the void swelling of copper for these irradiation conditions.

  4. Edge wave response on a barred beach with wind-sea and swell forcing

    NASA Astrophysics Data System (ADS)

    Contardo, Stephanie; Symonds, Graham; Segura, Laura

    2015-04-01

    The occurrence of short period wind-sea associated with a diurnal sea breeze, superimposed on longer period swell in South West Western Australia provides an opportunity to observe the response of infragravity (0.01-0.05 Hz) waves, in the nearshore, to both wind-sea and swell forcing. An alongshore array of pressure sensors and a cross-shore array of current velocity and pressure sensors are deployed at Secret Harbour, a barred beach near Perth. The observations show a stronger infragravity response to longer period incident swell than to short period wind-sea. Infragravity waves at Secret Harbour are generated by two mechanisms: breakpoint forcing and bound wave release. Breakpoint forcing is observed with both swell and wind-sea forcing while bound wave release is only observed in the presence of swell. Two mechanisms generate free infragravity waves during swell periods while only one mechanism is in place during wind-sea periods, providing an explanation for the stronger response to swell than wind-sea. Free infragravity waves propagating offshore after reflection at the shoreline are called leaky waves; those which are trapped to the shoreline by refraction are called edge waves. At Secret Harbour, both edge waves and leaky waves are detected. Leaky waves dominate with swell forcing while edge waves dominate with wind-sea forcing. Amongst edge waves, mode 0 waves are found to dominate in the absence of wind-sea, while higher mode edge waves dominate when wind-sea is present. We calculate the expected wavenumber-frequency distribution of edge wave and leaky wave energy, based on resonance conditions, using wave period, incidence angle and directional spreading, as proposed by Bowen and Guza (1978). Observations and predictions are in good agreement. However the model can be improved by quantifying the infragravity energy generated by both infragravity wave generation mechanisms. Bowen, A. J., and R. T. Guza (1978), Edge waves and surf beat, Journal of

  5. Monitoring mitochondrial membranes permeability in live neurons and mitochondrial swelling through electron microscopy analysis.

    PubMed

    Arrázola, Macarena S; Inestrosa, Nibaldo C

    2015-01-01

    Maintenance of mitochondrial membrane integrity is essential for mitochondrial function and neuronal viability. Apoptotic stimulus or calcium overload leads to mitochondrial permeability transition pore (mPTP ) opening and induces mitochondrial swelling, a common feature of mitochondrial membrane permeabilization. The first phenomenon can be evaluated in cells loaded with the dye calcein -AM quenched by cobalt, and mitochondrial swelling can be detected by electron microscopy through the analysis of mitochondrial membrane integrity. Here, we describe a live cell imaging assay to detect mitochondrial permeability transition and the development of a detailed analysis of morphological and ultrastructural changes that mitochondria undergo during this process.

  6. Impetigo presenting as an acute necrotizing swelling of the lower lip in an adult patient.

    PubMed

    Ghafoor, Mohammed; Halsnad, Moorthy; Fowell, Christopher; Millar, Brian G

    2012-06-01

    The authors present an unusual case of an acute swelling of the lower lip and septicemia in a 35-year-old, recent immigrant male arriving from India. The patient presented in our emergency department with a 48-hour history of a worsening, painful swelling of the lower lip. On presentation, he was pyrexial and the lip was found to be acutely inflamed with honey-colored crusting, pustular lesions, and induration . A diagnosis of impetigo leading to necrosis of the lip was established, a rare phenomenon potentially resulting in significant tissue destruction. Appropriate medical management achieved a good outcome and prevented disabling tissue loss of the orofacial region.

  7. Characterizing swells in the southern Pacific from seismic and infrasonic noise analyses

    NASA Astrophysics Data System (ADS)

    Barruol, Guilhem; Reymond, Dominique; Fontaine, Fabrice R.; Hyvernaud, Olivier; Maurer, Vincent; Maamaatuaiahutapu, Keitapu

    2006-03-01

    A temporary network of 10 broad-band seismic stations has been installed in French Polynesia for the Polynesian Lithosphere and Upper Mantle Experiment (PLUME). All the seismic stations were installed either on volcanic islands or on atolls of the various archipelagos of French Polynesia in a manner which complements the geographic coverage provided by the regional permanent stations. The primary aim of PLUME is to image the upper mantle structures related to plate motion and hotspot activity. However, because of its proximity to all sites, the ocean is responsible for a high level of noise in the seismic data and we show that these data can also be used to analyse ocean wave activity. The power spectral density (PSD) analyses of the seismic data recorded in French Polynesia show clear peaks in the 0.05-0.10 Hz band (periods between 10 and 20 s), which corresponds to swell frequencies. Clear peaks in this frequency band are also observed in infrasonic data recorded on Tahiti. Ground motion analysis shows that the swell-related seismic noise (SRSN) is linearly polarized in the horizontal plane and its amplitude decreases rapidly with the distance from the shore. The microseismic and the infrasonic `noise' amplitudes show very similar variations from station to station and both are strongly correlated with the swell amplitudes predicted by the National Oceanic and Atmospheric Administration (NOAA), wind-forced, `WaveWatch' models. The swell direction can be estimated from SRSN polarization analysis but this has to be done with care since, for some cases, the ground motions are strongly controlled by the islands' anisometric shapes and by swell refraction processes. We find cases, however, such as Tahiti or roughly circular Tuamotu atolls, where the azimuth of the swell is in good agreement with the seismic estimates. We, therefore, demonstrate that the SRSN and the infrasonic signal observed in French Polynesia can be used in such cases as a proxy for swell amplitude

  8. Diffusion and Equilibrium Swelling of Macromolecular Networks by Their Linear Homologs.

    DTIC Science & Technology

    1982-10-01

    inversely proportional toLLthe molecular wei ht of PD N 1473 EDIToNm OF INov a i SonsoLETEt /U I , j ’Po t* t 6/N1 0 102. 1- 0 14- 6601 SE6CURITY...should then provide a powerful measure of the entropic contribu- tions to the free energy of swelling for molecular networks in contact with compatible...restraints from molecular entanglements and the C 2 term in the strain- energy function. The degree of swelling with liquids having a molecular weight

  9. Swelling and collapse of polyelectrolyte gels in equilibrium with monovalent and divalent electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Yin, De-Wei; Olvera de la Cruz, Monica; de Pablo, Juan J.

    2009-11-01

    The swelling of polyelectrolyte (PE) gels by 1:1 and 2:1 salts is studied via osmotic ensemble Monte Carlo simulations at constant osmotic pressure and electrolyte chemical potential of a reservoir phase in equilibrium with a model PE network. Large molecular weight gels exhibit a remarkable swelling response to small changes in 2:1 salt concentration. Gel collapse is accompanied by the formation of a previously unknown heterogeneous nanostructure, predicted by theory and observed in simulations, consisting of regions dense in monomers coexisting with regions rich in mono- and divalent ions.

  10. Elastic, permeability and swelling properties of human intervertebral disc tissues: A benchmark for tissue engineering.

    PubMed

    Cortes, Daniel H; Jacobs, Nathan T; DeLucca, John F; Elliott, Dawn M

    2014-06-27

    The aim of functional tissue engineering is to repair and replace tissues that have a biomechanical function, i.e., connective orthopaedic tissues. To do this, it is necessary to have accurate benchmarks for the elastic, permeability, and swelling (i.e., biphasic-swelling) properties of native tissues. However, in the case of the intervertebral disc, the biphasic-swelling properties of individual tissues reported in the literature exhibit great variation and even span several orders of magnitude. This variation is probably caused by differences in the testing protocols and the constitutive models used to analyze the data. Therefore, the objective of this study was to measure the human lumbar disc annulus fibrosus (AF), nucleus pulposus (NP), and cartilaginous endplates (CEP) biphasic-swelling properties using a consistent experimental protocol and analyses. The testing protocol was composed of a swelling period followed by multiple confined compression ramps. To analyze the confined compression data, the tissues were modeled using a biphasic-swelling model, which augments the standard biphasic model through the addition of a deformation-dependent osmotic pressure term. This model allows considering the swelling deformations and the contribution of osmotic pressure in the analysis of the experimental data. The swelling stretch was not different between the disc regions (AF: 1.28±0.16; NP: 1.73±0.74; CEP: 1.29±0.26), with a total average of 1.42. The aggregate modulus (Ha) of the extra-fibrillar matrix was higher in the CEP (390kPa) compared to the NP (100kPa) or AF (30kPa). The permeability was very different across tissue regions, with the AF permeability (64 E(-16)m(4)/Ns) higher than the NP and CEP (~5.5 E(-16)m(4)/Ns). Additionally, a normalized time-constant (3000s) for the stress relaxation was similar for all the disc tissues. The properties measured in this study are important as benchmarks for tissue engineering and for modeling the disc's mechanical

  11. Data-Enhanced Modeling of Sea and Swell on the Continental Shelf

    DTIC Science & Technology

    2016-06-07

    Data-Enhanced Modeling of Sea and Swell on the Continental Shelf William C. O’Reilly and Thomas H.C. Herbers U.S. Naval Postgraduate School Dept. of...we will identify the types of wave data (eg. remotely sensed or in situ) and measurement locations (e.g. at the offshore model boundary or in the...TITLE AND SUBTITLE Data-Enhanced Modeling of Sea and Swell on the Continental Shelf 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

  12. Bowing-reactivity trends in EBR-II assuming zero-swelling ducts

    SciTech Connect

    Meneghetti, D.

    1994-03-01

    Predicted trends of duct-bowing reactivities for the Experimental Breeder Reactor II (EBR-II) are correlated with predicted row-wise duct deflections assuming use of idealized zero-void-swelling subassembly ducts. These assume no irradiation induced swellings of ducts but include estimates of the effects of irradiation-creep relaxation of thermally induced bowing stresses. The results illustrate the manners in which at-power creeps may affect subsequent duct deflections at zero power and thereby the trends of the bowing component of a subsequent power reactivity decrement.

  13. Changes in triphasic mechanical properties of proteoglycan-depleted articular cartilage extracted from osmotic swelling behavior monitored using high-frequency ultrasound.

    PubMed

    Wang, Q; Zheng, Y P; Niu, H J

    2010-03-01

    This study aims to obtain osmosis-induced swelling strains of normal and proteoglycan (PG) depleted articular cartilage using an ultrasound system and to investigate the changes in its mechanical properties due to the PG depletion using a layered triphasic model. The swelling strains of 20 cylindrical cartilage-bone samples collected from different bovine patellae were induced by decreasing the concentration of bath saline and monitored by the ultrasound system. The samples were subsequently digested by a trypsin solution for approximately 20 min to deplete proteoglycans, and the swelling behaviors of the digested samples were measured again. The bi-layered triphasic model proposed in our previous study (Wang et al., J Biomech Eng-Trans ASME 2007; 129: 413-422) was used to predict the layered aggregate modulus Ha from the data of depth-dependent swelling strain, fixed charge density and water content. It was found that the region near the bone, for the normal specimens, had a significantly higher aggregate modulus (Ha1 = 20.6 +/- 18.2 MPa) in comparison with the middle zone and the surface layer (Ha2 = 7.8 +/- 14.5 MPa and Ha3 = 3.6 +/- 3.2 MPa, respectively) (p < 0.001). The normalized thickness of the deep layer h1 was 0.68 +/- 0.20. After the trypsin digestion, the parametric values decreased to Ha1 = 13.6 +/- 9.6 MPa, Ha2 = 6.7 +/- 11.5 MPa, Ha3 = 2.7 +/- 3.2 MPa, and h1 = 0.57 +/- 0.28. Other models were also used to analyze data and the results were compared. This study showed that high-frequency ultrasound measurement combined with the triphasic modeling was capable of nondestructively quantifying the alterations in the layered mechanical properties of the proteoglycan-depleted articular cartilage.

  14. Engineering the van der Waals interaction in cross-linking-free hydroxide exchange membranes for low swelling and high conductivity.

    PubMed

    Gu, Shuang; Skovgard, Jason; Yan, Yushan S

    2012-05-01

    What a swell for hydroxides: The typical trade-off between swelling control and ion conductivity in ion-conducting polymer membranes is overcome by enhancement of van der Waals interactions among polymer chains. Using a quaternary phosphonium-functionalized polymer, the simple combination of high electron density of the polymer and large dipole moment of the functional group leads to low membrane swelling, high hydroxide conductivity, and excellent hydroxide exchange membrane fuel cell performance.

  15. 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

  16. 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

  17. Theoretical analysis of swelling characteristics of cylindrical uranium dioxide fuel pins with a niobium - 1-percent-zirconium clad

    NASA Technical Reports Server (NTRS)

    Saltsman, J. F.

    1973-01-01

    The relations between clad creep strain and fuel volume swelling are shown for cylindrical UO2 fuel pins with a Nb-1Zr clad. These relations were obtained by using the computer code CYGRO-2. These clad-strain - fuel-volume-swelling relations may be used with any fuel-volume-swelling model, provided the fuel volume swelling is isotropic and independent of the clad restraints. The effects of clad temperature (over a range from 118 to 1642 K (2010 to 2960 R)), pin diameter, clad thickness and central hole size in the fuel have been investigated. In all calculations the irradiation time was 500 hours. The burnup rate was varied.

  18. Molecular dynamics simulation of C/Si ratio effect on the irradiation swelling of β-SiC

    NASA Astrophysics Data System (ADS)

    Li, Yingying; Xiao, Wei; Li, Huailin

    2016-11-01

    The C/Si atom ratio effect on the irradiation swelling of β-SiC is studied using molecular dynamics (MD) simulations. The irradiation swelling decreases with the increase of C/Si ratio under the same irradiation conditions. The carbon cluster is the key issue for the irradiation swelling of non-stoichiometric SiC. The carbon cluster size increases with the increase of C/Si ratio and the number of cluster decreases with the increase of C/Si ratio after irradiation process. An analytical model is established to describe the C/Si ratio effect on irradiation swelling and it fits the MD data well.

  19. Hydrological modeling in swelling/shrinking peat soils

    NASA Astrophysics Data System (ADS)

    Camporese, M.; Ferraris, S.; Putti, M.; Salandin, P.; Teatini, P.

    2006-06-01

    Peatlands respond to natural hydrologic cycles of precipitation and evapotranspiration with reversible deformations due to variations of water content in both the unsaturated and saturated zone. This phenomenon results in short-term vertical displacements of the soil surface that superimpose to the irreversible long-term subsidence naturally occurring in drained cropped peatlands because of bio-oxidation of the organic matter. These processes cause changes in the peat structure, in particular, soil density and void ratio. The consequential changes in the hydrological parameters need to be incorporated in water flow dynamical models. In this paper, we present a new constitutive relationship for the soil shrinkage characteristic (SSC) in peats by describing the variation of porosity with moisture content. This model, based on simple physical considerations, is valid for both anisotropic and isotropic three-dimensional peat deformations. The capability of the proposed SSC to accurately describe the deformation dynamics has been assessed by comparison against a set of laboratory experimental results recently published. The constitutive relationship has been implemented into a Richards' equation-based numerical code and applied for the simulation of the peat soil dynamics as observed in a peatland south of the Venice Lagoon, Italy, in an ad hoc field experiment where the relevant parameters are continuously measured. The modeling results match well a large set of field data encompassing a period of more than 50 days and demonstrate that the proposed approach allows for a reliable reproduction of the soil vertical displacement dynamics as well as the hydrological behavior in terms of, for example, water flow, moisture content, and suction.

  20. Delayed effort-induced swelling with myofasciitis and systemic manifestations: A so far unrecognized type of pressure-induced urticaria

    PubMed Central

    Bursztejn, Anne-Claire; Lipsker, Dan

    2017-01-01

    Abstract Diseases characterized by recurrent symptoms with prolonged intervals without any clinical manifestations can pose diagnostic difficulties. Some diagnoses will be obvious but other situations can be very challenging. To nosologically delineate a new entity characterized by recurrent flares of induration of the forearms and legs with swelling of the extremities accompanied by intense fatigue and variable other symptoms. Retrospective observational study of patients recorded from 2000 to 2015. All patients included were seen during a consultation at the Dermatology Department of the University Hospital of Strasbourg, France. We retrieved the medical records from patients seen and recorded over the last 16 years having induration of the extremities, the forearm and the legs occurring between 4 and 12 hours after a physical effort accompanied by systemic signs that lasted for a few days. We analyzed in detail the clinical and biological features, evolution, and treatments of these patients. We included 6 males, with a mean age of 47 years; mean age at disease onset was 42. All patients were initially misdiagnosed as having rheumatic disorders. The mean delay before diagnosis was 5 years. The main complaint was painful induration or muscle soreness of the forearms and the legs associated with transient functional impairment and prolonged asthenia for a mean duration of 3.5 days. Induration of the deep soft tissues was very suggestive of myofasciitis. The delay between the triggering physical effort and the swelling was between 6 and 12 hours. Physical effort as triggering factor was never spontaneously mentioned. Two patients had partial response to high dose antihistamines and 2 other patients to the interleukin-1 inhibitor anakinra. One patient responded to hydroxychloroquine. The very stereotypical presentation in those 6 patients suggests that this is a recognizable entity characterized by effort-induced induration of forearms and/or legs, due to deep

  1. Swelling of clay-sulfate rocks and groundwater flow in tunnel engineering

    NASA Astrophysics Data System (ADS)

    Butscher, C.; Huggenberger, P.

    2009-12-01

    The governing goal of the presented study is to contribute to a better understanding of the complex coupled hydromechanical and geochemical processes that occur during rock swelling in clay-sulfate rocks. The swelling of clay-sulfate rocks, which produces major difficulties and high additional costs during tunnel construction and maintenance, is a well known threat in tunneling (Einstein, 1996). This threat is mostly counteracted on an engineering, technical level by constructive measures (Anagnostou, 2007). However, the processes which trigger these phenomena are at present far from being comprehensively understood. In this study, we aim to introduce a novel approach to this problem. We assume that groundwater circulation plays a major role in understanding the involved processes, and that changes in groundwater flow patterns induced by the tunnel excavation are responsible for the swelling phenomena. Generally, the swelling is caused by the transformation of anhydrite into gypsum under water uptake (hydration of anhydrite), entailing a 60% volume increase. However, the transformation takes place not in a direct, but in an indirect way, making a detour via anhydrite solution, transport of the solutes with groundwater flow, and precipitation at a different place. For this reason, the dynamics of groundwater flow in particular was taken into consideration in this study. The study is part of a project carried out at the Chienberg road tunnel in Switzerland (Huggenberger and Butscher, 2008). In this tunnel, swelling phenomena associated with heave of the tunnel invert and at the surface were observed during construction at two sections comprising clay-sulfate rocks. The study was designed to investigate the regional and local groundwater circulation systems and to link them to the observed swelling. In particular, the role of the topographic and geological framework (Tóth, 1995), the effects of heterogeneity and anisotropy, as well as scale effects were investigated

  2. Sequential deposition: optimization of solvent swelling for high-performance polymer solar cells.

    PubMed

    Liu, Yao; Liu, Feng; Wang, Hsin-Wei; Nordlund, Dennis; Sun, Zhiwei; Ferdous, Sunzida; Russell, Thomas P

    2015-01-14

    Organic solar cells based on a typical DPP polymer were systematically optimized by a solvent swelling assisted sequential deposition process. We investigated the influence of solvent swelling on the morphology and structure order of the swollen film and the resultant device performance. Morphological and structural characterization confirmed the realization of ideal bulk heterojunctions using a suitable swelling solvent. A trilayered morphology was also found with the conjugated polymer concentrated bottom layer, PC71BM concentrated top layer, and interpenetrated networks of donor and acceptor in the middle by solvent swelling instead of thermal annealing in the sequential solution processing method. We proposed a simple strategy to optimize the sequential deposition fabricated devices by tuning the concentration of the PC71BM solution instead of thermal annealing. The best device showed a PCE of 7.59% with a Voc of 0.61 V, Jsc of 17.95 mA/cm(2), and FF of 69.6%, which is the highest reported efficiency for devices fabricated by a sequential processing method and among the best results for DPP polymers.

  3. Effect of electrolytes on colloidal stability and swelling of hydroxypropyl cellulose microgels

    NASA Astrophysics Data System (ADS)

    Mithra, K.; Khandai, Santripti; Jena, Sidhartha S.

    2016-05-01

    Hydroxypropyl Cellulose (HPC) microgels were prepared by emulsion polymerization method. The volume phase transition temperature (VPTT) and swelling properties were investigated using Dynamic Light Scattering (DLS). The VPTT for the HPC microgels was found to be˜44°C. Microgel particles swelled˜'3' times of their original size on decreasing temperature from 50°C to 25 °C. In addition we have also studied the effect of salts, sodium nitrate and sodium bromide in the Hofmeister series on deswelling and colloidal stability of HPC microgels using DLS and turbidity measurements respectively. M icrogel particles swelled in presence of NaN03 when its concentration was increased from 10-4 to 0.5 M and deswelled beyond it. As oppose to this, swelling of microgels in presence of NaBr was seen only upto 10-3 M and beyond which deswelling of microgels was observed. The results obtained are consistent with Hofmeister series of anions. Turbidity results showed that the colloidal stability of HPC microgel dispersion was dependent on ionic strength and type of added salt. For both salts, stability of microgels was found to decrease with rise in salt concentration.

  4. SWELLING OF PEATS IN LIQUID METHYL, TETRAMETHYLENE AND PROPYL SULFOXIDES AND IN LIQUID PROPYL SULFONE

    EPA Science Inventory

    The interactions of methyl, tetramethylene, and propyl sulfoxides and propyl sulfone during sorption onto four de-waxed, acid-form peats have been studied by means of swelling measurements. The results for sulfoxides are displayed as het-eromolecular sorption isotherms, which plo...

  5. A dual thermal and photo-switchable shrinking-swelling supramolecular peptide dendron gel.

    PubMed

    Xie, Fan; Qin, Long; Liu, Minghua

    2016-01-18

    A supramolecular dendron gel was fabricated through the co-assembly of an L-glutamic acid terminated amphiphilic dendron and a positively charged azobenzene derivative, which showed a dual thermal and photo-switched reversible volume phase transition or shrinking/swelling.

  6. Prediction of postoperative facial swelling, pain and trismus following third molar surgery based on preoperative variables

    PubMed Central

    de Souza-Santos, Jadson A.; Martins-Filho, Paulo R.; da Silva, Luiz C.; de Oliveira e Silva, Emanuel D.; Gomes, Ana C.

    2013-01-01

    Objective: This paper investigates the relationship between preoperative findings and short-term outcome in third molar surgery. Study design: A prospective study was carried out involving 80 patients who required 160 surgical extractions of impacted mandibular third molars between January 2009 and December 2010. All extractions were performed under local anesthesia by the same dental surgeon. Swelling and maximal inter-incisor distance were measured at 48 h and on the 7th day postoperatively. Mean visual analogue pain scores were determined at four different time periods. Results: One-hundred eight (67.5%) of the 160 extractions were performed on male subjects and 52 (32.5%) were performed on female subjects. Median age was 22.46 years. The amount of facial swelling varied depending on gender and operating time. Trismus varied depending on gender, operating time and tooth sectioning. The influence of age, gender and operating time varied depending on the pain evaluation period (p < 0.05). Conclusions: Short-term outcomes of third molar operations (swelling, trismus and pain) differ depending on the patients’ characteristics (age, gender and body mass index). Moreover, surgery characteristics such as operating time and tooth sectioning were also associated with postoperative variables. Key words:Third molar extraction, pain, swelling, trismus, postoperative findings, prediction. PMID:23229245

  7. Reversible Structural Swell-Shrink and Recoverable Optical Properties in Hybrid Inorganic-Organic Perovskite.

    PubMed

    Zhang, Yupeng; Wang, Yusheng; Xu, Zai-Quan; Liu, Jingying; Song, Jingchao; Xue, Yunzhou; Wang, Ziyu; Zheng, Jialu; Jiang, Liangcong; Zheng, Changxi; Huang, Fuzhi; Sun, Baoquan; Cheng, Yi-Bing; Bao, Qiaoliang

    2016-07-26

    Ion migration in hybrid organic-inorganic perovskites has been suggested to be an important factor for many unusual behaviors in perovskite-based optoelectronics, such as current-voltage hysteresis, low-frequency giant dielectric response, and the switchable photovoltaic effect. However, the role played by ion migration in the photoelectric conversion process of perovskites is still unclear. In this work, we provide microscale insights into the influence of ion migration on the microstructure, stability, and light-matter interaction in perovskite micro/nanowires by using spatially resolved optical characterization techniques. We observed that ion migration, especially the migration of MA(+) ions, will induce a reversible structural swell-shrink in perovskites and recoverably affect the reflective index, quantum efficiency, light-harvesting, and photoelectric properties. The maximum ion migration quantity in perovskites was as high as approximately 30%, resulting in lattice swell or shrink of approximately 4.4%. Meanwhile, the evidence shows that ion migration in perovskites could gradually accelerate the aging of perovskites because of lattice distortion in the reversible structural swell-shrink process. Knowledge regarding reversible structural swell-shrink and recoverable optical properties may shed light on the development of optoelectronic and converse piezoelectric devices based on perovskites.

  8. Challenges and limitations in studying the shrink-swell and crack dynamics of vertisol soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The need to study the shrink-swell and crack properties of vertic soils has long been recognized given their dynamics in time and space, which modifies the physical properties that impact water and air movement in the soil, flow of water into the subsoil and ground water, and generally alter the hyd...

  9. SWELL1, a plasma membrane protein, is an essential component of volume-regulated anion channel

    PubMed Central

    Qiu, Zhaozhu; Dubin, Adrienne E.; Mathur, Jayanti; Tu, Buu; Reddy, Kritika; Miraglia, Loren J.; Reinhardt, Jürgen; Orth, Anthony P.; Patapoutian, Ardem

    2014-01-01

    Summary Maintenance of a constant cell volume in response to extracellular or intracellular osmotic changes is critical for cellular homeostasis. Activation of a ubiquitous volume-regulated anion channel (VRAC) plays a key role in this process; however, its molecular identity in vertebrates remains unknown. Here, we used a cell-based fluorescence assay and performed a genome-wide RNAi screen to find components of VRAC. We identified SWELL1 (LRRC8A), a member of a four-transmembrane protein family with unknown function, as essential for hypotonicity-induced iodide influx. SWELL1 is localized to the plasma membrane, and its knockdown dramatically reduces endogenous VRAC currents and regulatory cell volume decrease in various cell types. Furthermore, point mutations in SWELL1 cause a significant change in VRAC anion selectivity, demonstrating that SWELL1 is an essential VRAC component. These findings enable further molecular characterization of the VRAC channel complex and genetic studies for understanding the function of VRAC in normal physiology and disease. PMID:24725410

  10. Manual lymph drainage efficiently reduces postoperative facial swelling and discomfort after removal of impacted third molars.

    PubMed

    Szolnoky, G; Szendi-Horváth, K; Seres, L; Boda, K; Kemény, L

    2007-09-01

    The removal of wisdom teeth is often associated with severe postoperative edema and pain, and operation on the third molar can cause local inflammation that impairs lymph transport. The objective of the study was to assess the efficacy of manual lymph drainage (MLD) in reducing swelling following bilateral wisdom tooth removal. Ten consecutive patients with bilateral impacted wisdom teeth that required surgical removal were enrolled in the study. Each patient was postoperatively treated with MLD (after Vodder's method) on one side of the neck region with the untreated contralateral side as a control. Swelling was evaluated using a tape-measure placed in contact with the skin. The six landmarks of measurement included tragus-lip junction, tragus-pogonion, mandibular angle-external corner of eye, mandibular angle-ala nasi, mandibular angle-lip junction, and mandibular angle-median point of chin. Subjective assessment of MLD was conducted with self-evaluation using a visual analogue bar scale (VAS, range 0-100 mm). Of the 6 linear measurements, 4 lines (2, 4, 5, 6) showed a significant reduction of swelling on the side of MLD compared to the untreated side. Mean score of VAS of pretreatment condition was 35.5 +/- 20.60 mm that decreased to 22 +/- 19.32 mm measured after MLD (p=0.0295). This initial study demonstrates that MLD may promote an improvement of lymph circulation and work in an adjunctive role for reduction of postoperative swelling and pain following removal of impacted third molars.

  11. Swelling suppression in phosphorous-modified Fe-Cr-Ni alloys during neutron irradiation

    SciTech Connect

    Lee, E.H.; Packan, N.H.

    1988-01-01

    Phosphorous-containing austenitic alloys in the solution annealed condition were irradiated at 745--760/degree/K. The alloys were variations on Fe--13Cr--15Ni--0.05P with respective additions of 0.8 Si, 0.2 Ti, or 0.8 Si /plus/ 0.2 Ti; also included were low (0.01) and zero P compositions (all values in wt. %). The reference ternary and the two phosphorous-only variations contained little precipitation and numerous voids and swelled rapidly, while the three variants containing P with Si and/or Ti showed little or no void formation and profuse phosphide precipitation. Results indicate that phosphorous in solution alone does not have a major influence on void swelling, whereas fine-scale phosphide precipitation is quite effective at eliminating void formation. The principal mechanism restricting swelling is the effect of the dense precipitate microstructure. These precipitates foster profuse cavity nucleation which in turn dilutes the helium atoms (and more time) in order for individual cavities to surpass their critical size and number of gas atoms necessary for subsequent growth as voids. This mechanism for swelling suppression was not found to be particularly sensitive to moderate variations in either the dislocation or cavity densities; the mechanism is strongest at elevated temperature where the critical quantities are large and is less effective at lower temperatures where the critical quantities are small. 19 refs., 10 figs., 3 tabs.

  12. Thermal Expansion and Swelling of Cured Epoxy Resin Used in Graphite/Epoxy Composite

    NASA Technical Reports Server (NTRS)

    Adamson, M. J.

    1979-01-01

    The thermal expansion and swelling of resin material as influenced by variations in temperature during moisture absorption is discussed. Comparison measurements using composites constructed of graphite fibers and each of two epoxy resin matrices are included. Polymer theory relative to these findings is discussed and modifications are proposed.

  13. Permeability and selectivity of reverse osmosis membranes: correlation to swelling revisited.

    PubMed

    Dražević, Emil; Košutić, Krešimir; Freger, Viatcheslav

    2014-02-01

    Membrane swelling governs both rejection of solutes and permeability of polymeric membranes, however very few data have been available on swelling in water of salt-rejecting reverse osmosis (RO) membranes. This study assesses swelling, thickness and their relation to water permeability for four commercial polyamide (PA) RO membranes (SWC4+, ESPA1, XLE and BW30) using atomic force microscopy (AFM) and attenuated total reflection Fourier transform IR spectroscopy (ATR-FTIR). ATR-FTIR offered a significantly improved estimate of the actual barrier thickness of PA, given AFM is biased by porosity ("fluffy parts") or wiggling of the active layer or presence of a coating layer. Thus obtained intrinsic permeability (permeability times thickness) and selectivity of aromatic polyamides plotted versus swelling falls well on a general trend, along with previously reported data on several common materials showing RO and NF selectivity. The observed general trend may be rationalized by viewing the polymers as a random composite medium containing molecularly small pores. The results suggest that the combination of a rigid low dielectric matrix, limiting the pore size, with multiple hydrophilic H-bonding sites may be a common feature of RO/NF membranes, allowing both high permeability and selectivity.

  14. Harnessing Buckling to Design Architected Materials that Exhibit Effective Negative Swelling.

    PubMed

    Liu, Jia; Gu, Tianyu; Shan, Sicong; Kang, Sung H; Weaver, James C; Bertoldi, Katia

    2016-08-01

    Inspired by the need to develop materials capable of targeted and extreme volume changes during operation, numerical simulations and experiments are combined to design a new class of soft architected materials that achieve a reduction of projected surface-area coverage during swelling.

  15. Gas-bubble growth mechanisms in the analysis of metal fuel swelling

    SciTech Connect

    Gruber, E.E.; Kramer, J.M.

    1986-06-01

    During steady-state irradiation, swelling rates associated with growth of fission-gas bubbles in metallic fast reactor fuels may be expected to remain small. As a consequence, bubble-growth mechanisms are not a major consideration in modeling the steady-state fuel behavior, and it is usually adequate to consider the gas pressure to be in equilibrium with the external pressure and surface tension restraint. On transient time scales, however, various bubble-growth mechanisms become important components of the swelling rate. These mechanisms include growth by diffusion, for bubbles within grains and on grain boundaries; dislocation nucleation at the bubble surface, or ''punchout''; and bubble growth by creep. Analyses of these mechanisms are presented and applied to provide information on the conditions and the relative time scales for which the various processes should dominate fuel swelling. The results are compared to a series of experiments in which the swelling of irradiated metal fuel was determined after annealing at various temperatures and pressures. The diffusive growth of bubbles on grain boundaries is concluded to be dominant in these experiments.

  16. The swelling mechanism of cathodes in Li/(CFx)(sub n) cells

    NASA Technical Reports Server (NTRS)

    Margalit, Nehemiah; Baxam, Carl C.

    1992-01-01

    Active material particles spatial arrangement in combination with the nature of the electrochemical reduction mechanism were found to be the major cause of excessive swelling in cathodes in Li/(CF(x))n cells. A better understanding of the chemical reaction mechanism, a possible new role for the carbon, and a model for cathode growth are discussed.

  17. Swelling in light water reactor internal components: Insights from computational modeling

    SciTech Connect

    Stoller, Roger E.; Barashev, Alexander V.; Golubov, Stanislav I.

    2015-08-01

    A modern cluster dynamics model has been used to investigate the materials and irradiation parameters that control microstructural evolution under the relatively low-temperature exposure conditions that are representative of the operating environment for in-core light water reactor components. The focus is on components fabricated from austenitic stainless steel. The model accounts for the synergistic interaction between radiation-produced vacancies and the helium that is produced by nuclear transmutation reactions. Cavity nucleation rates are shown to be relatively high in this temperature regime (275 to 325°C), but are sensitive to assumptions about the fine scale microstructure produced under low-temperature irradiation. The cavity nucleation rates observed run counter to the expectation that void swelling would not occur under these conditions. This expectation was based on previous research on void swelling in austenitic steels in fast reactors. This misleading impression arose primarily from an absence of relevant data. The results of the computational modeling are generally consistent with recent data obtained by examining ex-service components. However, it has been shown that the sensitivity of the model s predictions of low-temperature swelling behavior to assumptions about the primary damage source term and specification of the mean-field sink strengths is somewhat greater that that observed at higher temperatures. Further assessment of the mathematical model is underway to meet the long-term objective of this research, which is to provide a predictive model of void swelling at relevant lifetime exposures to support extended reactor operations.

  18. Lipid diffusion and swelling in a phase separated biocompatible thermoplastic elastomer.

    PubMed

    Fittipaldi, Mauro; Grace, Landon R

    2016-12-01

    Lipid uptake was analyzed via gravimetric measurements in a biocompatible poly(styrene-block-isobutylene-block-styrene) (SIBS) copolymer. Absorption followed Fickian diffusion behavior very closely, although some deviation was noticed once saturation was reached. Diffusion parameters of three different SIBS formulations were calculated and used to predict the behavior of a fourth type based on molecular weight and relative polystyrene content. SIBS with lower polystyrene content and molecular weight showed lower physical stability and developed surface cracks that propagated with exposure to the lipid medium. Saturation lipid content varied from 45% to 63% by weight and was inversely related to polystyrene content, suggesting most of the plasticization is occurring in the isobutylene phase of SIBS. Moreover, swelling of specimens was monitored throughout the immersion in the lipid medium and ranged from 32% to 58%. Swelling in formulations with lower hard phase (polystyrene) was significantly higher than the swelling in SIBS with higher hard phase content. This is consistent with lipid-induced plasticization occurring in the soft (polyisobutylene) segments, relaxing the polymer network and leading to increased swelling and lipid uptake. The biocompatibility and tailorability of SIBS through control of hard/soft phase ratio offer significant advantages for in vivo applications. However, the lipophilic nature of the material and the associated degradation may render the polymer unusable in certain applications. The predictive model of lipid uptake introduced here will allow more accurate evaluation of lipid susceptibility during the preliminary design phase of SIBS-based in vivo structures.

  19. Effect of yttrium additions on void swelling in Liquid Metal Fast Breeder Reactor candidate cladding alloys

    SciTech Connect

    Hopson, R.D.

    1981-10-01

    Candidate Liquid Metal Fast Breeder Reactor cladding alloys AL1 (Fe-26% Ni-9% Cr) and AL2 (Fe-35% Ni-12% Cr) without and with the addition of 0.1% yttrium were bombarded by 4 MeV/sup 56/Fe/sup 2 +/ ions without and with simultaneous bombardment by 0.4 MeV /sup 4/He/sup +/ ions. These bombardments were conducted at various irradiation temperatures to determine the effect of yttrium on void swelling. The addition of yttrium decreased peak swelling for 4 MeV /sup 56/Fe/sup 2 +/ ion bombarded AL1 and AL2 by 28% and 20%, respectively. In all cases where similar sample comparisons were made (i.e., undoped with undoped and doped with doped) and where bombardment conditions were similar (i.e., single with single beam and dual with dual beam), AL1 showed less peak swelling than did AL2. Simultaneously implanting helium during heavy-ion bombardment increased peak swelling in undoped and doped AL1 by factors of 2.3 and 2.6, respectively.

  20. Hyperelastic modeling of swelling in fibrous soft tissue with application to tracheal angioedema.

    PubMed

    Gou, Kun; Pence, Thomas J

    2016-01-01

    Angioedema, the rapid swelling of under-skin tissue, is typically triggered by complex biochemical processes that disrupt an original steady state filtration of liquid through the tissue. Swelling stabilizes once a new steady state is achieved in which the tissue has significantly increased liquid content. These processes are controlled by events at the molecular to the cellular length scale. For describing consequences at organ level length scales it is useful to invoke consolidated continuum mechanics treatments within a generalized hyperelastic framework. We describe the challenges associated with such modeling and demonstrate their use in the context of tracheal angioedema. The trachea is modeled as a two layered cylindrical tube. The inner layer and outer layer represent the soft mucosal tissue and the stiffer cartilaginous tissue respectively. Axially oriented fibers contribute anisotropy to the inner layer, and the swelling is largely confined to this layer. A boundary value problem is formulated; existence and uniqueness is verified. Numerical solutions track airway constriction as a function of mucosal swelling.