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Sample records for causing periorbital swelling

  1. Frontal and orbital bone infarctions causing periorbital swelling in patients with sickle cell anemia

    SciTech Connect

    Garty, I.; Koren, A.; Garzozi, H.

    1984-10-01

    Two cases of unilateral and bilateral periorbital hematomas occurred in patients with sickle cell anemia. The cause of periorbital swelling in these cases was found to be orbital and frontal bone infarctions, respectively, diagnosed by technetium Tc 99m medronate bone scintigraphy. To our knowledge, periorbital bone infarction, as a part of the differential diagnosis of periorbital hematoma and as part of the possible ocular manifestations in patients with sickle cell anemia, has not previously been described.

  2. An unusual case of acute periorbital swelling.

    PubMed

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

    2014-01-01

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

  3. A rare cause of lateral facial swelling.

    PubMed

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

    2014-01-01

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

  4. 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

  5. Periorbital Hyperpigmentation: A Comprehensive Review

    PubMed Central

    Sarkar, Rashmi; Ranjan, Rashmi; Garg, Shilpa; Garg, Vijay K.; Sonthalia, Sidharth; Bansal, Shivani

    2016-01-01

    Periorbital hyperpigmentation is a commonly encountered condition. There is very little scientific data available on the clinical profile and pathogenesis of periorbital hyperpigmentation. Periorbital hyperpigmentation is caused by various exogenous and endogenous factors. The causative factors include genetic or heredity, excessive pigmentation, postinflammatory hyperpigmentation secondary to atopic and allergic contact dermatitis, periorbital edema, excessive vascularity, shadowing due to skin laxity and tear trough associated with aging. There are a number of treatment options available for periorbital hyperpigmentation. Among the available alternatives to treat dark circles are topical depigmenting agents, such as hydroquinone, kojic acid, azelaic acid, and topical retinoic acid, and physical therapies, such as chemical peels, surgical corrections, and laser therapy, most of which are tried scientifically for melasma, another common condition of hyperpigmentation that occurs on the face. The aim of treatment should be to identify and treat the primary cause of hyperpigmentation as well as its contributing factors. PMID:26962392

  6. American kestrel (Falco spaverius) fledgling with severe bilateral periorbital swelling and infection with Mycoplasma buteonis, Avibacterium (Pasteurella) gallinarum, and Staphylococcus pasteuri.

    PubMed

    Bezjian, Marisa; Bezjian, Marisa

    2014-06-01

    Abstract: A female American kestrel (Falco spaverius) fledgling was found on the ground with a suspected trauma to the right eye and open-mouth breathing. During the first 2 days of hospitalization, the bird developed severe bilateral periorbital cellulitis, blepharoedema, and sinusitis. The periocular tissues of the right globe were devitalized and communicated with a fistula at the commissure of the right side of the beak. The blepharoedema of the left eye was aspirated and yielded a dark colored malodorous fluid, which was submitted for aerobic bacterial and Mycoplasma cultures. Results showed a mixed infection with Mycoplasma buteonis, Avibacterium gallinarum, and Staphylococcus pasteuri, all of which are not commonly isolated from birds of prey. With antimicrobial therapy, supportive care, and surgical debridement of the right periocular necrotic tissues and adhesed phthisical globe, the kestrel recovered from this severe mixed upper respiratory infection. PMID:25115041

  7. Periorbital (eyelid) dermatides.

    PubMed

    Wolf, Ronni; Orion, Edith; Tüzün, Yalçın

    2014-01-01

    Physicians in various specialties-and dermatologists in particular-frequently encounter various forms of inflammation of the eyelids and of the anterior surface of the eye. Distinguishing the cause of itchy, painful, red, edematous eyelids is often difficult. Because the uppermost layer of the eyelids is part of the skin that wraps the entire body, almost every skin disease in the textbook can affect the periorbital area as well. In this contribution, we focused on the most common such disorders that require special consideration, as a result of their special appearance, their challenging diagnosis, or the nature of their treatment. We reviewed the key features of several common dermatides that affect the eyelids, such as atopic dermatitis, seborrheic dermatitis, allergic contact dermatitis, airborne contact dermatitis, rosacea, psoriasis, and others. We focused on the special clinical features, causes, and treatments specific to the delicate skin of the eyelids. Because structures of the eye itself (i.e., the conjunctiva, the cornea, the lens, and the retina) may be involved in some of the discussed periorbital skin diseases, we found it useful to add a brief summary of the eyelid complications of those diseases. We then briefly reviewed some acute sight-threatening and even life-threatening infections of the eyelids, although dermatologists are not likely to be the primary care physicians responsible for treating them. PMID:24314387

  8. Swelling

    MedlinePlus

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

  9. 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 ...

  10. Urethroscrotal Fistula: A Rare Cause of Scrotal Swelling

    PubMed Central

    Parlak, Selcuk; Okay, Aysun E.

    2016-01-01

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

  11. Urethroscrotal Fistula: A Rare Cause of Scrotal Swelling

    PubMed Central

    Parlak, Selcuk; Okay, Aysun E.

    2016-01-01

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

  12. Deep venous thrombosis as a cause of stump swelling in two lower extremity amputee patients.

    PubMed

    Chong, D K; Panju, A

    1993-09-01

    Two patients who were initially treated for an infection as a cause for their swollen stump were subsequently found to have deep venous thrombosis. The diagnosis was made noninvasively by compressive ultrasound (CU) scanning. DVT should be considered in the different diagnosis of stump swelling in the otherwise stable, post-rehabilitated lower extremity amputee patient.

  13. Mechanisms involved in the swelling of erythrocytes caused by Pacific and Caribbean ciguatoxins.

    PubMed

    Sauviat, Martin-Pierre; Boydron-Le Garrec, Raphaële; Masson, Jean-Baptiste; Lewis, Richard L; Vernoux, Jean-Paul; Molgó, Jordi; Laurent, Dominique; Benoit, Evelyne

    2006-01-01

    The mechanisms underlying the swelling of frog red blood cells (RBC), induced by Pacific (P-CTX-1) and Caribbean (C-CTX-1) ciguatoxins (CTXs), were investigated by measuring the length, width and surface of their elliptic shape. P-CTX-1 (0.5 to 5 nM) and C-CTX-1 (1 nM) induced RBC swelling within 60 min. The CTXs-induced RBC swelling was blocked by apamin (1 microM) and by Sr(2+) (1 mM). P-CTX-1-induced RBC swelling was prevented and inhibited by H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (27 microM), an inhibitor of soluble guanylate cyclase (sGC), and NOS blockade by NG methyl-l-arginine (l-NMA; 10 microM). Cytochalasin D (cytD, 10 microM) increased RBC surface and mimicked CTX effect but did not prevent the P-CTX-1-induced l-NMA-sensitive extra increase. Calculations revealed that P-CTX-1 and cytD increase RBC total surface envelop and volume. These data strongly suggest that the molecular mechanisms underlying CTXs-induced RBC swelling involve the NO pathway by an activation of the inducible NOS, leading to sGC activation which modulates intracellular cGMP and regulates L-type Ca(2+) channels. The resulting increase in intracellular Ca(2+) content, in turn, disrupts the actin cytoskeleton, which causes a water influx and triggers a Ca(2+)-activated K(+) current through SK2 isoform channels. PMID:16364667

  14. [Thymic cyst--an uncommon cause of neck swelling in children].

    PubMed

    Staníková, A; Jakubíková, J; Spánik, P; Martanovic, P

    2003-07-01

    The thymus cyst, which is difficult to recognize before the operation may occur in children as a painless swelling of the neck An asymptomatic course of about 100 cases has been reported in the English-written literature until 2002. The cyst is localized along the thymopharyngeal duct, i.e. from the mandible angle to the upper mediastinum. The authors describe cases of two patients. In the male patient the swelling resembled pathologically enlarged lymphatic nodes implicating malignant lymphoma. In the female patient the palpation examination of the swelling suggested the presence of lymphangioma. The radiological examination revealed a cystic formation or a liquefied lymphatic node. The operation on the patients revealed polycystic formation containing a clear brown liquid. Histological examination proved the formation to be a thymus cyst. The neck swelling in children may also be caused by developmental errors--a lateral cyst from the brachial arc, lymphangioma, hemangioma, medial cyst, thyroid gland cyst, parathyroid gland cyst, aberrant or ectoscopic thyroid gland, struma, laryngocoele, lymphatic nodopathy, pathologically changes salivary glands, phlegmona or abscess in the parapharyngeal space, teratoma on the neck, benign tumors (dermoid, epidermoid, neurofibroma, lipoma, lymphoma) and malignant tumors (sarcoma, lymph node metastases). The available literature does not describe any case of thymus cyst of the neck, which should be considered in differential diagnosis of swelling of the neck in children diagnosed before the operation. The final diagnosis may be established only after histological examination. Surgical extirpation is the primary therapy of the neck thymus cyst. The authors describe embryology, histology, present a survey of literature and deal with differential diagnosis, diagnosis and therapy of the neck thymus cyst in children.

  15. Periorbital adenocarcinoma in a bearded dragon (Pogona vitticeps).

    PubMed

    Darrow, Brett G; Johnstone McLean, Nancy S; Russman, Shirley E; Schiller, Chris A

    2013-07-01

    A 4.5-year-old female bearded dragon (Pogona vitticeps) presented for periorbital swelling affecting the left eye. A well-organized, hypoechoic mass was noted ventral and medial to the globe on ocular ultrasound. The mass continued to grow despite antibiotic therapy, and an exenteration was performed. The mass was diagnosed via histopathology and immunohistochemical staining as a probable lacrimal gland carcinoma, although a Harderian gland origin could not definitively be ruled out. The tumor recurred following removal, and the lizard died 2 months postoperatively.

  16. Rhinosporidiosis of lacrimal sac: An interesting case of orbital swelling

    PubMed Central

    Basu, Sandip Kanti; Bain, Jayanta; Maity, Kuntal; Chattopadhyay, Debarati; Baitalik, Debasis; Majumdar, Bijay Kumar; Gupta, Vivek; Kumar, Ashwini; Dalal, Bibhas Saha; Malik, Anu

    2016-01-01

    Rhinosporidiosis is a chronic localized granulomatous disease caused by Rhinosporidium seeberi, an aquatic protistan parasite belonging to a clade, Mesomycetozoea. Infestation of Rhinosporidiosis to the eye and adnexa is termed oculosporidiosis, in such cases, conjunctival mucosa is mostly involved; however in our case, it involved only the lacrimal sac and deeper periorbital tissue and presented as a case of orbital swelling. Surgical excision of the lesion was done, postoperatively dapsone therapy was given for 6 months, and the patient responded very well with no recurrence till date. PMID:27003980

  17. Periorbital aesthetic surgery with the KTP laser.

    PubMed

    Ginsbach, G

    1995-01-01

    The eyes are regarded as the windows to the soul. Many expressions of mood may be derived from the appearance of the eyes--mad, sad, bad, criminal, sweet, friendly, mystic. In addition, love and flirtatiousness, self-consciousness, pride, modesty, anger, youth, and age are shown in the expression of our eyes. The eyes and the periorbital region therefore challenge our surgical skill to improve the patient's overall well-being to be looked at each day in the mirror. The potassium titanyl phosphate (KTP) laser in many indications helps us to fulfill the patient's expectations concerning pain, oozing, bruising, swelling, outpatient surgery, and early return to work and normal social activities. With the cutting fiber device, an accurate removal of skin and fat or even tumors is possible in this region with practically no side effects. The frontal lift, eyebrow lift, direct or through coronal incision, as well as temporal lifting are easily accessible and carried out by this device. Glabellar frowns may also be removed endoscopically. Further, the KTP laser may be used for transconjunctival blepharoplasty.

  18. Orbital cellulitis with periorbital abscess secondary to methicillin-resistant Staphylococcus aureus (MRSA) sepsis in an immunocompetent neonate.

    PubMed

    Rao, Lavanya G; Rao, Krishna; Bhandary, Sulatha; Shetty, Priyanka Ranjan

    2015-01-01

    This article advocates the need for early incision and drainage of periorbital abscesses. We report a case of a 1.5-month-old neonate with orbital cellulitis and periorbital abscess, which had rapidly developed over a period of 3 days. Treatment history revealed methicillin-resistant Staphylococcus aureus sepsis treated with intravenous vancomycin, and incision and drainage of abscesses at multiple sites (left parotid region, upper and lower limbs). A small swelling noted on the left temporal region on discharge from the hospital was treated with oral cotrimoxazole. However, it spread rapidly to involve the periorbital tissue and the bones of the orbital walls to form a periorbital abscess and orbital cellulitis. PMID:25899513

  19. Immediate reaction to lidocaine with periorbital edema during upper blepharoplasty

    PubMed Central

    Presman, Benjamin; Vindigni, Vincenzo; Tocco-Tussardi, Ilaria

    2016-01-01

    Introduction Blepharoplasty is the fourth most commonly performed cosmetic surgery in the US, with 207,000 operations in 2014. Lidocaine is the preferred anesthetic agent for blepharoplasty. Presentation of case We describe the unusual case of acute periorbital edema following local anesthesia with lidocaine for upper blepharoplasty. At present, only two other reports of periorbital reactions to lidocaine are present in the literature. The reactions observed are significant palpebral swelling and erythema with scaling of the cheek. Fortunately the swelling, although marked, is transient in nature and resolves almost spontaneously without affecting the visual acuity. Discussion Patients reporting adverse reactions should be screened for allergy according to the standard protocols, but skin testing has only been reported to be positive in less than 10% of all cases and allergy confirmation with IgE is even more rare. Conclusion In clinical practice, we recommend that patient should be informed about the possibility of recurrence of an adverse reaction in case of re-exposure to lidocaine, even in the vast majority of cases where true allergy could not be proven. In case of further need for local anesthesia with history of an adverse event, a different agent may be chosen even from the same class (another amide) as cross-reactions in the amide group are rare. Otherwise, an anesthetic from the ester group can also be safely used. PMID:26785079

  20. Periorbital Injectables: Understanding and Avoiding Complications

    PubMed Central

    Hwang, Catherine J

    2016-01-01

    Periorbital rejuvenation with neurotoxins and dermal fillers address several aging changes. Safe and effective results require a thorough understanding of periorbital anatomy, proper injection techniques, and complications of these products. Prompt recognition and treatment of complications can minimize their adverse impacts. Complications can be divided into ischaemic and non-ischaemic effects. Hylauronidase, an enzyme that degrades hyaluronic acid, may improve outcomes after intravascular hyaluronic acid fillers. PMID:27398006

  1. Popliteal Venous Aneurysm: A Rare Cause of Recurrent Pulmonary Emboli and Limb Swelling

    SciTech Connect

    Russell, David A. Robinson, Graham J.; Johnson, Brian F.

    2008-09-15

    Popliteal venous aneurysm is a rare cause of recurrent pulmonary embolism, although the true incidence of aneurysm is probably underestimated. One-third of patients suffer further embolic events despite therapeutic anticoagulation. We report the case of a 59-year-old male who presented with recurrent PEs over a period of 12 years despite anticoagulation therapy. A thrombophilia screen and abdominal ultrasound were normal at that time. He reattended with recurrent pulmonary emboli, left calf swelling, and a mass in his left popliteal fossa causing limitation of knee movement. Venous duplex and MRI of his popliteal fossa demonstrated a thrombosed true popliteal venous aneurysm with popliteal and superficial femoral vein occlusion. In view of the mass effect we proceeded to surgical excision of his aneurysm after prophylactic placement of an IVC filter. The patient regained normal knee function with intensive inpatient physiotherapy. He has been recommenced on lifelong anticoagulant. The presentation, investigation, and management of the condition are briefly discussed. We suggest that a bilateral lower limb duplex is performed to exclude venous aneurysm in all patients presenting with pulmonary embolism in which an underlying source cannot otherwise be identified and no thrombophilic tendency is detected.

  2. Absolute Ethanol Embolization of Arteriovenous Malformations in the Periorbital Region

    SciTech Connect

    Su, Li-xin; Jia, Ren-Bing; Wang, De-Ming Lv, Ming-Ming Fan, Xin-dong

    2015-06-15

    ObjectiveArteriovenous malformations (AVMs) involving the periorbital region are technically challenging clinical entities to manage. The purpose of the present study was to present our initial experience of ethanol embolization in a series of 16 patients with auricular AVMs and assess the outcomes of this treatment.MethodsTranscatheter arterial embolization and/or direct percutaneous puncture embolization were performed in the 16 patients. Pure or diluted ethanol was manually injected. The follow-up evaluations included physical examination and angiography at 1- to 6-month intervals.ResultsDuring the 28 ethanol embolization sessions, the amount of ethanol used ranged from 2 to 65 mL. The obliteration of ulceration, hemorrhage, pain, infection, pulsation, and bruit in most of the patients was obtained. The reduction of redness, swelling, and warmth was achieved in all the 16 patients, with down-staging of the Schobinger status for each patient. AVMs were devascularized 100 % in 3 patients, 76–99 % in 7 patients, and 50–75 % in 6 patients, according to the angiographic findings. The most common complications were necrosis and reversible blister. No permanent visual abnormality was found in any of the cases.ConclusionEthanol embolization is efficacious and safe in the treatment of AVMs in the periorbital region and has the potential to be accepted as the primary mode of therapy in the management of these lesions.

  3. Subcutaneous emphysema of periorbital region after stainless steel crown preparation in a young child.

    PubMed

    Khandelwal, Vishal; Agrawal, Piyush; Agrawal, Deepak; Nayak, Prathibha Anand

    2013-05-22

    Subcutaneous emphysema occurs when air is forced beneath the tissue, leading to swelling, crepitus on palpation and has the potential to spread along the fascial planes. This report describes the youngest case of subcutaneous emphysema related to dental treatment that has been documented to date. In addition to the patient's age, the case is of interest because periorbital subcutaneous emphysema is a rarest complication of stainless steel crown procedure.

  4. An unusual cause of acute bilateral optic disk swelling with macular star in a 9-year-old girl.

    PubMed

    I-Linn, Zena Lim; Long, Quah Boon

    2007-01-01

    We report a rare case of bilateral optic disk swelling with macular exudates and cottonwool spots secondary to a pheochromocytoma in a 9-year-old girl. Malignant hypertensive changes in the eyes are uncommon and may sometimes resemble neuroretinitis. Overaggressive treatment of malignant hypertension can cause optic nerve infarction, leading to blindness.

  5. Optimizing Reconstruction with Periorbital Transplantation: Clinical Indications and Anatomic Considerations

    PubMed Central

    Sosin, Michael; Mundinger, Gerhard S.; Dorafshar, Amir H.; Iliff, Nicholas T.; Christensen, Joani M.; Christy, Michael R.; Bojovic, Branko

    2016-01-01

    Background: Complex periorbital subunit reconstruction is challenging because the goals of effective reconstruction vary from one individual to another. The purpose of this article is to explore the indications and anatomic feasibility of periorbital transplantation by reviewing our institutional repository of facial injury. Methods: Institutional review board approval was obtained at the R Adams Cowley Shock Trauma Center for a retrospective chart review conducted on patients with periorbital defects. Patient history, facial defects, visual acuity, and periorbital function were critically reviewed to identify indications for periorbital or total face (incorporating the periorbital subunit) vascularized composite allotransplantation. Cadaveric allograft harvest was then designed and performed for specific patient defects to determine anatomic feasibility. Disease conditions not captured by our patient population warranting consideration were reviewed. Results: A total of 7 facial or periorbital transplant candidates representing 6 different etiologies were selected as suitable indications for periorbital transplantation. Etiologies included trauma, burn, animal attack, and tumor, whereas proposed transplants included isolated periorbital and total face transplants. Allograft recovery was successfully completed in 4 periorbital subunits and 1 full face. Dual vascular supply was achieved in 5 of 6 periorbital subunits (superficial temporal and facial vessels). Conclusions: Transplantation of isolated periorbital structures or full face transplantation including periorbital structures is technically feasible. The goal of periorbital transplantation is to re-establish protective mechanisms of the eye, to prevent deterioration of visual acuity, and to optimize aesthetic outcomes. Criteria necessary for candidate selection and allograft design are identified by periorbital defect, periorbital function, ophthalmologic evaluation, and defect etiology. PMID:27014557

  6. Coloration in different areas of facial skin is a cue to health: The role of cheek redness and periorbital luminance in health perception.

    PubMed

    Jones, Alex L; Porcheron, Aurélie; Sweda, Jennifer R; Morizot, Frederique; Russell, Richard

    2016-06-01

    Looking healthy is a desirable trait, and facial skin color is a predictor of perceived health. However, skin conditions that cause dissatisfaction with appearance are specific to particular facial areas. We investigated whether color variation in facial skin is related to perceived health. Study 1 defined three areas based on color differences between faces perceived as healthy or unhealthy: the forehead, periorbital areas, and the cheeks. Periorbital luminance and cheek redness predicted perceived health, as did global skin yellowness. In Study 2, increased luminance and redness caused faces to be perceived as healthier, but only when the increase was in the periorbital and cheek areas, respectively. Manipulating each area separately in Study 3 revealed cheek redness and periorbital luminance equally increased perceived health, with low periorbital luminance more negatively affecting perceptions. These findings show that color variation in facial skin is a cue for health perception in female faces. PMID:26967010

  7. Periorbital Dirofilariasis: A Rare Case from Western India

    PubMed Central

    Kulkarni, Varsha

    2016-01-01

    Dirofilariasis is a zoonotic disease caused commonly by Dirofilaria repens and Dirofilaria immitus. The definitive hosts are domestic dogs and cats. Human beings are accidental dead end hosts, and acquire infestation through mosquito bites. So far, very few cases have been reported from western India. We report a case of a 27-year-old male who presented with preseptal cellulitis right eye and a firm mass in the lower lid. Histopathological examination after surgical excision of the mass revealed a diagnosis of dirofilariasis. Although rare in Western India a diagnosis of dirofilariasis should be considered in cases of preseptal cellulitis associated with a periorbital mass. PMID:27134918

  8. Periorbital cellulitis due to cutaneous anthrax.

    PubMed

    Gilliland, Grant; Starks, Victoria; Vrcek, Ivan; Gilliland, Connor

    2015-12-01

    Virgil's plague of the ancient world, Bacillus anthracis, is rare in developed nations. Unfortunately rural communities across the globe continue to be exposed to this potentially lethal bacterium. Herein we report a case of periorbital cutaneous anthrax infection in a 3-year-old girl from the rural area surrounding Harare, Zimbabwe with a brief review of the literature.

  9. Periorbital Hyperpigmentation in Patients with Xanthelasma Palpebrarum

    PubMed Central

    Kouris, Anargyros; Agiasofitou, Efthymia; Antoniou, Christina; Kontochristopoulos, Georgios

    2016-01-01

    Background: Xanthelasma palpebrarum refers to xanthomas that occur more often near the inner canthus of the eyelid. Periorbital hyperpigmentation presents as a dark area surrounding the eyelids. Objective: In the present study, the authors examined the prevalence and the associated factors of periorbital hyperpigmentation among patients with xanthelasma. Methods: One hundred and fourteen patients with xanthelasma palpebrarum were examined for the presence of dark circles. Detailed questionnaires regarding the history of diabetes, hypothyroidism, smoking status, and weight were completed by all patients. They were also tested for serum lipids (cholesterol, low-density lipoprotein, triglycerides, apolipoprotein A and apolipoprotein B). Results: From the 114 patients with xanthelasma, 94 (82.4%) were diagnosed with periorbital hyperpigmentation. At the time of the survey, 46 patients were smokers (48.9%), 23 of them had hypothyroidism (24.4%), and 16 patients were obese (17%). Only four patients had a history of diabetes. Cholesterol levels were elevated in 65 patients (69.1%). In 52 patients (55.3%), low-density lipoprotein was increased and in 51 patients (54.2%), both cholesterol and low-density lipoprotein were elevated. Apolipoprotein A was increased in 35 patients (37.2%), whereas apolipoprotein B was increased in 23 patients (24.4%). Conclusions: This study showed that a significant number of patients with xanthelasma exhibited periorbital hyperpigmentation. Smoking, obesity, and hyperlipidemia were observed in these patients. PMID:27721911

  10. 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

  11. Premenstrual inguinal swelling and pain caused by endometriosis in the Bartholin gland: a case report.

    PubMed

    Robotti, Guido; Canepari, Elena; Torresi, Mario

    2015-03-01

    Endometriosis is a pathological condition characterized by the presence of endometrial tissue outside the endometrium. The authors describe a case of endometriosis in the Bartholin gland, which was initially diagnosed as a Bartholin gland cyst. The correct diagnosis was later made on the basis of the patient history and the results of the ultrasound examination. Endometriosis in the Bartholin gland should be considered in the presence of dyspareunia, cyclic swelling and pain at the vulvar level, and characteristic ultrasound findings.

  12. Arteriolymphatic Fistula: An Unusual Cause of Spontaneous Swelling in the Left Supraclavicular Region.

    PubMed

    Karuppiah Viswanathan, Ashok Mithra; Irodi, Aparna; Keshava, Shyamkumar N; Aneez, Joseph; Karthik, Gunasekaran

    2016-09-01

    An abnormal fistulous communication between an artery and lymphatic system is a rare occurrence. We report a 38-year-old male presenting with sudden onset, spontaneous, pulsatile swelling in the left supraclavicular region following a recent cardiac catheterisation via right femoral arterial access. On evaluation, he was found to have a femoral arteriolymphatic fistula. He was managed conservatively with ultrasound-guided compression with complete resolution of symptoms at follow-up. This case describes a hitherto unknown complication of percutaneous vascular cannulation presenting in an unusual manner, diagnosed with Doppler Ultrasonography and CT angiography and managed effectively with a non-invasive therapeutic image-guided manoeuvre. PMID:27184364

  13. A case of odontogenic orbital cellulitis causing blindness by severe tension orbit.

    PubMed

    Park, Chang Hyun; Jee, Dong Hyun; La, Tae Yoon

    2013-02-01

    We report a very rare case of odontogenic orbital cellulitis causing blindness by severe tension orbit. A 41-yr old male patient had visited the hospital due to severe periorbital swelling and nasal stuffiness while he was treated for a periodontal abscess. He was diagnosed with odontogenic sinusitis and orbital cellulitis, and treated with antibiotics. The symptoms were aggravated and emergency sinus drainage was performed. On the next day, a sudden decrease in vision occurred with findings of ischemic optic neuropathy and central retinal artery occlusion. Deformation of the eyeball posterior pole into a cone shape was found from the orbital CT. A high-dose steroid was administered immediately resulting in improvements of periorbital swelling, but the patient's vision had not recovered. Odontogenic orbital cellulitis is relatively rare, but can cause blindness via rapidly progressing tension orbit. Therefore even the simplest of dental problems requires careful attention.

  14. Lipoma Arborescens: Review of an Uncommon Cause for Swelling of the Knee

    PubMed Central

    De Vleeschhouwer, M.; Van Den Steen, E.; Vanderstraeten, G.; Huysse, W.; De Neve, J.; Vanden Bossche, L.

    2016-01-01

    Lipoma arborescens is a rare cause of chronic monoarticular arthritis, with only a few cases reported in the literature. It is most commonly seen in the knee, but cases in other joints such as the wrist, shoulder, and elbow have also been described. It is a benign condition, in which the subsynovial tissue is replaced diffusely by mature fat cells. We describe a case involving the knee and discuss the symptoms, diagnosis, and treatment. PMID:27293937

  15. Trabeculectomy trapdoor separation with allergic periorbital dermatitis: an unusual late-onset complication of guarded filtration surgery.

    PubMed

    Ooi, Kenneth G-J; Adler, Paul A; Goldberg, Ivan

    2007-08-01

    Hypotony post trabeculectomy may be the result of excessive aqueous outflow. Herein a case of an elderly man with excessive filtration 2 years post trabeculectomy resulting from trapdoor separation associated with allergic periorbital dermatitis is presented. Quaternary ammonium compounds are a significant cause of allergic periorbital dermatitis. Chronic rubbing associated with allergies to multiple topical quaternary ammonium compound-containing ophthalmic preparations is likely to have contributed to the trapdoor autotrauma and separation in this man with a background of allergic contact dermatitis. PMID:17760641

  16. Reconstruction of periorbital soft tissue defects.

    PubMed

    Berli, Jens U; Merbs, Shannath L; Grant, Michael P

    2014-10-01

    Because of the complex anatomy and fine mechanics of the periorbital soft tissues, the reconstruction of this region can be particularly daunting. Through a structured assessment of the defect, based on subunit analysis and thorough understanding of the surgical layers, we believe to allow the reconstructive surgeon to develop an algorithmic approach to these complex problems. The sequela of a suboptimal reconstruction do not only result in an inferior aesthetic result, but also have the potential for long-term functional problems such as epiphora, dry eye, ptosis, eyelid retraction, and thus requiring secondary surgery. There is no better time to aim for a perfect reconstruction than at the time of the initial surgery. In this chapter, we hope to encourage the reader to strengthen and recapitulate these analytical skills and present the most commonly used and studied techniques to help achieve a reproducible functional and aesthetically appealing result. PMID:25397712

  17. Comprehensive Treatment of Periorbital Region with Hyaluronic Acid

    PubMed Central

    Rocha, Camila Roos Mariano Da; Bastos, Julien Toni De; Silva, Priscila Mara Chaves e

    2015-01-01

    The periorbital subunit is one of the first facial regions to show signs of aging, primarily due to volume depletion of the soft tissue and bony resorption. Surgical and office-based nonsurgical procedures form an important basis for periorbital rejuvenation. It is important to make a detailed clinical evaluation of the patient to indicate the most appropriate procedure to be performed. With the objective of showing a nonsurgical procedure for the rejuvenation of the periorbital area, the authors describe a technique of applying fillers in the upper and lower periorbital regions, paying attention to the anatomy of this facial region and the type of product to be used besides the expected results of the procedure and its possible adverse effects and complications. The nonsurgical rejuvenation of the periorbicular region with hyaluronic acid is a new and innovative technique. In the opinion of the authors, it is a great aesthetic impact area and consequently brings high satisfaction to patients. PMID:26155325

  18. [Poorly healing periorbital wounds. Therapeutic use of maggots].

    PubMed

    Pitz, S; Renieri, G; Gericke, A

    2012-05-01

    The treatment of poorly healing wounds, although not a typical problem in the periorbital area, has been enriched by the option of biosurgery, the therapeutic application of larvae of the blow fly (Lucilia sericata).

  19. Atypical periorbital xanthogranulomas associated with systemic benign lymphoepithelial lesions.

    PubMed

    Butterfield, J H; Bartley, G B

    1994-12-01

    The report reviews the clinical, laboratory, and pathologic features of a 47-year-old woman with systemic benign lymphoepithelial lesions in whom atypical periorbital xanthogranulomas with rare central necrosis subsequently developed.

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

    PubMed

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

    2014-05-01

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

  1. Scrotal swelling

    MedlinePlus

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

  2. Clinical outcome of surgical treatment for periorbital basal cell carcinoma.

    PubMed

    Kakudo, Natsuko; Ogawa, Yutaka; Suzuki, Kenji; Kushida, Satoshi; Kusumoto, Kenji

    2009-11-01

    Basal cell carcinoma (BCC) has a predilection for the periorbital region, which is a special, prominent, cosmetic, functional area to protect the eyeball. For squamous cell carcinoma and melanoma, extensive resection with reconstruction is performed. In contrast, for BCC, resection is often confined to a small to medium-sized area, necessitating higher-quality reconstructive surgery. We analyze the surgical outcomes of treatment for periorbital BCC, and evaluate reconstruction method after resection. Forty-nine patients with periorbital BCC had surgery in our hospital over 20 years. Age, gender of the patients, and size, localization, and histology of the tumor, and surgical procedures, and their early and late complications were analyzed retrospectively. BCC was most frequently occurred in the lower lid (55%), followed by inner canthus (19%), upper lid (17%), and outer canthus (9%). The histologic classifications were solid (80%), morphea (7%), mix (7%), superficial (2%), keratotic (2%), and adenoid (2%). Recurrence of the tumor was observed in 2 advanced cases in patients treated with resection of the tumor including surrounding tissue 5 mm from the margin. A rotation advancement cheek flap procedure was most frequently applied. Horizontal shift of the skin was most effective to prevent postoperative lagophthalmos. BCC occurred most frequently in the lower lid within the periorbital area. Rotation advancement of cheek flap with horizontal shift of the skin is most effective procedure in both appearance and function of the eyelid. PMID:19801921

  3. Intermittent facial swelling

    PubMed Central

    Pope, Charlie; Gopala Pillai, Suresh Kumar

    2014-01-01

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

  4. Foot, leg, and ankle swelling

    MedlinePlus

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

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

    PubMed

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

    2013-01-01

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

  6. Physiological and lifestyle factors contributing to risk and severity of peri-orbital dark circles in the Brazilian population*

    PubMed Central

    Matsui, Mary S; Schalka, Sérgio; Vanderover, Garrett; Fthenakis, Christina G.; Christopher, J; Bombarda, Patricia Camarano Pinto; Bueno, Juliana Regina; Viscomi, Bianca Lenci Inácio; Bombarda Júnior, Mário Sérgio

    2015-01-01

    BACKGROUND Peri-orbital dark circles are a cosmetic concern worldwide, and have been attributed to hyperpigmentation from allergy or atopic dermatitis, blood stasis, structural shadowing effects, and a thin epidermis/dermis under the eye. It is of interest to better understand lifestyle and demographic risk factors and the relative impact of melanin, blood and epidermal/dermal factors on the severity of Peri-orbital dark circles. OBJECTIVE To compare by non-invasive imaging the impact of biological factors to a visual grading scale for Peri-orbital dark circles, and test the correlation of various demographic factors with Peri-orbital dark circles. METHODS Subjects completed a lifestyle and health survey, and Peri-orbital dark circles severity was evaluated using standardized photographs. Hyperspectral image analysis was used to assess the contributions of melanin, blood volume, degree of blood oxygen saturation, and dermal scattering. RESULTS Family history was the most significant risk factor for Peri-orbital dark circles. The average age of onset was 24 years, and earlier onset correlated with higher severity scores. Asthma was significantly associated with Peri-orbital dark circles scores, but self-reported allergy was not. In this study, sleep was not correlated with Peri-orbital dark circles scores. Hyperspectral imaging indicated that melanin was the dominant correlate for Peri-orbital dark circles severity, while oxygen saturation was secondary. The difference between under-eye and cheek measurements for ∆L*and ∆E* were the most significant instrumental parameters correlated with visual assessment of Peri-orbital dark circles severity. CONCLUSION Although typically associated with lack of sleep, risk of Peri-orbital dark circles is primarily hereditary. The main factors contributing to the appearance of Peri-orbital dark circles are melanin and (deoxygenated) blood. PMID:26375218

  7. A temperature-sensitive allele of a putative mRNA splicing helicase down-regulates many cell wall genes and causes radial swelling in Arabidopsis thaliana.

    PubMed

    Howles, Paul A; Gebbie, Leigh K; Collings, David A; Varsani, Arvind; Broad, Ronan C; Ohms, Stephen; Birch, Rosemary J; Cork, Ann H; Arioli, Tony; Williamson, Richard E

    2016-05-01

    The putative RNA helicase encoded by the Arabidopsis gene At1g32490 is a homolog of the yeast splicing RNA helicases Prp2 and Prp22. We isolated a temperature-sensitive allele (rsw12) of the gene in a screen for root radial swelling mutants. Plants containing this allele grown at the restrictive temperature showed weak radial swelling, were stunted with reduced root elongation, and contained reduced levels of cellulose. The role of the protein was further explored by microarray analysis. By using both fold change cutoffs and a weighted gene coexpression network analysis (WGCNA) to investigate coexpression of genes, we found that the radial swelling phenotype was not linked to genes usually associated with primary cell wall biosynthesis. Instead, the mutation has strong effects on expression of secondary cell wall related genes. Many genes potentially associated with secondary walls were present in the most significant WGCNA module, as were genes coding for arabinogalactans and proteins with GPI anchors. The proportion of up-regulated genes that possess introns in rsw12 was above that expected if splicing was unrelated to the activity of the RNA helicase, suggesting that the helicase does indeed play a role in splicing in Arabidopsis. The phenotype may be due to a change in the expression of one or more genes coding for cell wall proteins.

  8. Ammonia-induced Na,K-ATPase/ouabain-mediated EGF receptor transactivation, MAPK/ERK and PI3K/AKT signaling and ROS formation cause astrocyte swelling.

    PubMed

    Dai, Hongliang; Song, Dan; Xu, Junnan; Li, Baoman; Hertz, Leif; Peng, Liang

    2013-11-01

    Ammonia toxicity is clinically important and biologically poorly understood. We reported previously that 3mM ammonia chloride (ammonia), a relevant concentration for hepatic encephalopathy studies, increases production of endogenous ouabain and activity of Na,K-ATPase in astrocytes. In addition, ammonia-induced upregulation of gene expression of α2 isoform of Na,K-ATPase in astrocytes could be inhibited by AG1478, an inhibitor of the EGF receptor (EGFR), and by PP1, an inhibitor of Src, but not by GM6001, an inhibitor of metalloproteinase and shedding of growth factor, suggesting the involvement of endogenous ouabain-induced EGF receptor transactivation. In the present cell culture study, we investigated ammonia effects on phosphorylation of EGF receptor and its intracellular signal pathway towards MAPK/ERK1/2 and PI3K/AKT; interaction between EGF receptor, α1, and α2 isoforms of Na,K-ATPase, Src, ERK1/2, AKT and caveolin-1; and relevance of these signal pathways for ammonia-induced cell swelling, leading to brain edema, an often fatal complication of ammonia toxicity. We found that (i) ammonia increases EGF receptor phosphorylation at EGFR(845) and EGFR(1068); (ii) ammonia-induced ERK1/2 and AKT phosphorylation depends on the activity of EGF receptor and Src, but not on metalloproteinase; (iii) AKT phosphorylation occurs upstream of ERK1/2 phosphorylation; (iv) ammonia stimulates association between the α1 Na,K-ATPase isoform, Src, EGF receptor, ERK1/2, AKT and caveolin-1; (v) ammonia-induced ROS production might occur later than EGFR transactivation; (vi) both ammonia induced ERK phosphorylation and ROS production can be abolished by canrenone, an inhibitor of ouabain, and (vii) ammonia-induced cell swelling depends on signaling via the Na,K-ATPase/ouabain/Src/EGF receptor/PI3K-AKT/ERK1/2, but in response to 3mM ammonia it does not appear until after 12h. Based on literature data it is suggested that the delayed appearance of the ammonia-induced swelling at

  9. Swelling-resistant nuclear fuel

    DOEpatents

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

    2011-12-27

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

  10. 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.

  11. Botfly larva masquerading as periorbital cellulitis: identification by point-of-care ultrasonography.

    PubMed

    Minakova, Elena; Doniger, Stephanie J

    2014-06-01

    Myiasis, or the infiltration of the botfly larvae, is a relatively frequent problem encountered by travelers to parts of Latin America. This is a novel case report that documents a Dermatobia hominis infestation of the left facial region with secondary periorbital cellulitis diagnosed by point-of-care ultrasonography.

  12. Periorbital cellulitis in children: Analysis of outcome of intravenous antibiotic therapy.

    PubMed

    Gonçalves, Rita; Menezes, Carlos; Machado, Rute; Ribeiro, Isabel; Lemos, José A

    2016-08-01

    Periorbital cellulitis is a relatively common ocular disease in the pediatric population. Early diagnosis of this disease with a prompt intervention is critical to avoid vision and life-threatening complications. In the last years, medical therapy has been expanding for the treatment of orbital cellulitis, instead of the standard surgical approach. The purpose of this study was to describe the outcome of treatment with intravenous antibiotic of periorbital cellulitis in children. A retrospective review of all children admitted with periorbital cellulitis in our hospital between January 2002 and July 2013 was conducted. Cases were divided in two subgroups, pre-septal and post-septal infection. The demographics, clinical findings, treatment and outcomes were analyzed. In total 110 children were included, 93 with pre-septal and 17 with post-septal cellulitis. The mean age was 3.5 years in children with pre-septal cellulitis and 5.5 years in those with post-septal cellulitis (p = 0.149). For both subgroups the most common predisposing factor was sinusitis. Intravenous antibiotic therapy was successful in all except one patient with an orbital abscess who required surgical intervention. In our study complete recovery was achieve in all (except for one) children with periorbital cellulitis treated with intravenous antibiotics only. PMID:27192038

  13. SYNERESIS AND SWELLING OF GELATIN.

    PubMed

    Kunitz, M

    1928-11-20

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

  14. 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.

  15. Secretory vesicle swelling by atomic force microscopy.

    PubMed

    Cho, Sang-Joon; Jena, Bhanu P

    2006-01-01

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

  16. Mitosis is swell.

    PubMed

    Zatulovskiy, Evgeny; Skotheim, Jan M

    2015-11-23

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

  17. Mitosis is swell

    PubMed Central

    Zatulovskiy, Evgeny

    2015-01-01

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

  18. Bifurcated Superficial Temporal Artery Island Flap for the Reconstruction of a Periorbital Burn: An Innovation

    PubMed Central

    Elbatawy, Amr; Aly, Gaber M.; Ayad, Wael; Helmy, Yasser; Helmy, Emad; Sholkamy, Khallad; Dahshan, Hazem; Al-Hady, Abdallah

    2016-01-01

    Background: Facial burns represent between one-fourth and one-third of all burns. The long-term sequelae of periorbital burns include significant ectropion and lagophthalmos as a result of secondary burn contractures in the lower and upper eyelids, in addition to complete or incomplete alopecia of the eyebrows. Methods: A retrospective study of 14 reconstructive procedures for 12 postburn faces was conducted with all procedures performed since 2010 at the Department of Plastic Surgery, Al-Hussein University Hospital, and at the Craniofacial Unit, Nasser Institute Hospital. Four patients experienced chemical burns, and 8 patients experienced thermal burns. All patients underwent periorbital reconstruction using a bifurcated superficial temporal artery island flap to reconstruct the eyebrows, correct the lagophthalmos, and release the ectropion in both the upper and the lower eyelids. Two patients underwent bilateral periorbital flap reconstruction. The mean age of patients was 29 years, and the study was conducted on 8 males and 4 females. Patient satisfaction was assessed using a questionnaire completed by all patients postoperatively. Results: The complete release of both the upper and the lower eyelids was achieved in all cases, together with ideal replacement of brow hair; no complications were noted, apart from one case in which a loss of hair density in the new eyebrow was observed, combined with the partial loss of the flap in the lower eyelid. Patient satisfaction results were collected and assembled in a table. Conclusion: A bifurcated superficial temporal artery island flap is an innovative flap for reconstructing both burned eyebrows and eyelids. PMID:27482487

  19. [Nasal endoscopic surgery for osteoid osteoma of the periorbital skull base: a case report].

    PubMed

    Huang, Yun; Zhu, Xinhua; Liu, Yuehui

    2016-02-01

    Osteoid osteoma was first reported in 1935 by Jaffe. It is a kind of benign bone disease with the limitation of well-defined lesions. It is rarely seen in the periorbital region. The only symptom of the patient was unilateral proptosis of right. The result of MRI examination was cystic masses in the edge of the right orbit. The tumor was complete removed by the nasal endoscopic approach during the surgery. Pathology result was reported as osteoid osteoma. There was no significant complications of diplopia, visual acuity decreased, enophthalmos, cerebrospinal fluid leakage and others. PMID:27373105

  20. Treatment of a periorbital cyst in a dog by creation of a permanent drainage opening.

    PubMed

    Kaiser, S; Driesen, A; Malberg, S; Kramer, M; Thiel, C

    2015-01-01

    An inflammatory periorbital cyst with secondary pressure atrophy of the maxilla was treated by surgical creation of a drainage opening to the nasal cavity in a 4-year-old Yorkshire Terrier. Following treatment, clinical signs resolved and computed tomography 5 weeks after surgery confirmed the permanence of the drainage opening. Eight months later, the dog showed no clinical abnormalities. Therefore, the procedure described in this report may offer a suitable treatment option in cases where the cyst's size or localization prevents complete excision.

  1. Clinical Photography for Periorbital and Facial Aesthetic Practice.

    PubMed

    Nair, Akshay Gopinathan; Santhanam, Aparna

    2016-01-01

    External cutaneous photography involves photographic documentation, which helps in treatment planning, documentation of facial features, teaching, publishing and pre- and post-procedural comparisons. The key is not simply documenting, but documenting it the right way and ensuring that photography is standardised and reproducible. In this review, basic photography techniques, standardised and reproducible angles such as frontal, oblique and lateral views and specific photographic angles for conditions such as facial rejuvenation are discussed. Use of photography accessories and a few tips on how to click good photographs in the examination room and how to achieve consistency in standardised photography are also presented. External photography in ophthalmic and facial plastic surgery like any other speciality too has standardised guidelines. Even small variations cause a drastic change in the photos and it's clinical and research value. Unless stringent criteria are met, the photographs lose their relevance and impact. PMID:27398013

  2. Clinical Photography for Periorbital and Facial Aesthetic Practice.

    PubMed

    Nair, Akshay Gopinathan; Santhanam, Aparna

    2016-01-01

    External cutaneous photography involves photographic documentation, which helps in treatment planning, documentation of facial features, teaching, publishing and pre- and post-procedural comparisons. The key is not simply documenting, but documenting it the right way and ensuring that photography is standardised and reproducible. In this review, basic photography techniques, standardised and reproducible angles such as frontal, oblique and lateral views and specific photographic angles for conditions such as facial rejuvenation are discussed. Use of photography accessories and a few tips on how to click good photographs in the examination room and how to achieve consistency in standardised photography are also presented. External photography in ophthalmic and facial plastic surgery like any other speciality too has standardised guidelines. Even small variations cause a drastic change in the photos and it's clinical and research value. Unless stringent criteria are met, the photographs lose their relevance and impact.

  3. Clinical Photography for Periorbital and Facial Aesthetic Practice

    PubMed Central

    Nair, Akshay Gopinathan; Santhanam, Aparna

    2016-01-01

    External cutaneous photography involves photographic documentation, which helps in treatment planning, documentation of facial features, teaching, publishing and pre- and post-procedural comparisons. The key is not simply documenting, but documenting it the right way and ensuring that photography is standardised and reproducible. In this review, basic photography techniques, standardised and reproducible angles such as frontal, oblique and lateral views and specific photographic angles for conditions such as facial rejuvenation are discussed. Use of photography accessories and a few tips on how to click good photographs in the examination room and how to achieve consistency in standardised photography are also presented. External photography in ophthalmic and facial plastic surgery like any other speciality too has standardised guidelines. Even small variations cause a drastic change in the photos and it's clinical and research value. Unless stringent criteria are met, the photographs lose their relevance and impact. PMID:27398013

  4. Retained periorbital and intracranial air-gun pellets causing sclopetaria and visual loss☆

    PubMed Central

    Al-Amry, Mohammad; Al-Taweel, Hassan; Al-Enazi, Nawaf; Alrobaian, Malek; Al-Othaimeen, Saleh

    2013-01-01

    Three healthy males presented on separate occasions to the emergency room at the King Khaled Eye Specialist Hospital (KKESH) after sustaining trauma by air-gun pellets. Clinical examination indicated sclopetaria in all the cases. The foreign bodies (air-gun pellets) were imbedded in different locations (subconjunctival, intraorbital, and intracranial). All cases resulted in a profound and permanent visual loss. The management of this traumatic injury is discussed and concurs with the published literature. PMID:25278803

  5. Cheek and periorbital peculiar discoid lupus erythematosus: rare clinical presentation mimicking tinea faciei, cutaneous granulomatous disease or blepharitis.

    PubMed

    Nakamura, Satoshi; Yamada, Tomoko; Umemoto, Naoka; Nakamura, Toshinobu; Wakatabi, Koji; Iida, Eri; Masaki, Masumi; Kakurai, Maki; Demitsu, Toshio

    2015-01-01

    We present clinically peculiar facial discoid lupus erythematosus (DLE) that mimicked tinea faciei. Although DLE is a chronic autoimmune dermatosis, it has a variety of rare clinical presentations, including periorbital DLE, comedonic DLE and hypertrophic DLE recently. In this case, a scaly, erythematous lesion on the eyelid and the central healed, mildly elevated, annularly distributed facial DLE mimicked tinea faciei, complicating our diagnosis.

  6. The Swelling of Olympic Gels

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  7. Doppler-assisted vascular pedicle flaps in eyelid and periorbital reconstruction.

    PubMed

    Yeatts, R P; Newsom, R W; Matthews, B L

    1996-09-01

    The use of a transcutaneous ultrasonic Doppler flow detector to identify the supratrochlear and superficial temporal arteries permits the design of narrow-based, thin-tipped forehead flaps for use in medial canthal and eyelid reconstruction. In the 13 cases described, the axial, vascular supply of a proposed myocutaneous forehead flap was determined with a transcutaneous ultrasonic Doppler flow detector permitting narrow-based pedicle widths of 0.8 to 1.2 cm. The design of the distal portion of the flap was determined by the primary defect. The width of the flap varied from 1.5 to 4.0 cm, with the flap's axial length limited only by the hairline. This use of the ultrasonic Doppler flow detector, permitting narrow-based, thin-tipped vascular pedicle flaps, has assisted in refining the concept of forehead flaps and has made these flaps an acceptable primary reconstructive technique in the periorbital region. PMID:8790111

  8. Bilateral periorbital necrotizing fasciitis following exposure to Holi colors: a case report.

    PubMed

    Chauhan, Deepender; Arora, Ritu; Das, Sima; Shroff, Daraius; Narula, Ritesh

    2007-01-01

    Holi festival is celebrated in India traditionally by applying colors on one another. Various ocular adverse effects of these colors have been reported including conjunctivitis and corneal abrasion. We report a case of bilateral periorbital necrotizing fasciitis, following exposure to Holi colors. General physicians might encounter more such cases after exposure to Holi colors. In India, these colors are prepared on a small scale and lack any quality checks. Use of such toxic colors should be discouraged, and all doctors should caution people against using synthetic dyes. This case report highlights the need to put manufacturing of Holi colors under guidelines of the Food and Drug Cosmetic Act and the Bureau of Indian Standards. PMID:17699947

  9. Late periorbital haemorrhage following functional endoscopic sinus surgery: a caution for potential day case surgery

    PubMed Central

    Arya, Arvind Kumar; Machin, David; Al-Jassim, Hadi

    2006-01-01

    Background Orbital complications following functional endoscopic sinus surgery (FESS) are fortunately rare. They are usually easily and rapidly recognizable. Case presentation We present an unusual case of a forty-five year old woman who underwent routine FESS and was not packed nasally after the procedure. Six hours later she started bleeding and nasal packs were inserted. She soon developed unilateral periorbital bruising and within hours her condition had worsened so much that the viability of the eye was thrown into question. She underwent medial and lateral canthotomies and made an uneventful post-operative recovery. Conclusion This rare case demonstrates that late, brisk post-operative bleeding can occur after FESS with potentially catastrophic consequences. Clinicians should be aware that discharging patients after FESS too early may lead to medico-legal problems. PMID:16734910

  10. Bilateral periorbital necrotizing fasciitis following exposure to Holi colors: A case report

    PubMed Central

    Arora, Ritu; Das, Sima; Shroff, Daraius; Narula, Ritesh

    2007-01-01

    Holi festival is celebrated in India traditionally by applying colors on one another. Various ocular adverse effects of these colors have been reported including conjunctivitis and corneal abrasion. We report a case of bilateral periorbital necrotizing fasciitis, following exposure to Holi colors. General physicians might encounter more such cases after exposure to Holi colors. In India, these colors are prepared on a small scale and lack any quality checks. Use of such toxic colors should be discouraged, and all doctors should caution people against using synthetic dyes. This case report highlights the need to put manufacturing of Holi colors under guidelines of the Food and Drug Cosmetic Act and the Bureau of Indian Standards. PMID:17699947

  11. Bilateral periorbital necrotizing fasciitis following exposure to Holi colors: a case report.

    PubMed

    Chauhan, Deepender; Arora, Ritu; Das, Sima; Shroff, Daraius; Narula, Ritesh

    2007-01-01

    Holi festival is celebrated in India traditionally by applying colors on one another. Various ocular adverse effects of these colors have been reported including conjunctivitis and corneal abrasion. We report a case of bilateral periorbital necrotizing fasciitis, following exposure to Holi colors. General physicians might encounter more such cases after exposure to Holi colors. In India, these colors are prepared on a small scale and lack any quality checks. Use of such toxic colors should be discouraged, and all doctors should caution people against using synthetic dyes. This case report highlights the need to put manufacturing of Holi colors under guidelines of the Food and Drug Cosmetic Act and the Bureau of Indian Standards.

  12. Neck Swelling (Symptom Checker)

    MedlinePlus

    ... You may have a viral illness or, rarely, GERMAN MEASLES (RUBELLA). If you have a facial rash, ... see your doctor. Stay away from pregnant women. German measles can harm unborn children and cause complications, ...

  13. Foot swelling (image)

    MedlinePlus

    ... buildup of fluid in the body is called edema. Edema is commonly seen in the feet and ankles, ... particularly noticeable in these locations. Common causes of edema are prolonged standing, prolonged sitting, pregnancy, being overweight, ...

  14. The superiority of combined continuous wave Doppler examination over periorbital Doppler for the detection of extracranial carotid disease.

    PubMed Central

    Trockel, U; Hennerici, M; Aulich, A; Sandmann, W

    1984-01-01

    Non-invasive examination of 431 vessels in 333 patients with cerebrovascular disease in all stages was performed in order to compare the reliability of the periorbital Doppler test alone and together with the more difficult insonation of the carotid arteries in the neck (combined Doppler). These findings were compared with those of subsequent arteriography. Extracranial obstructive (greater than 50%) carotid disease was detected with 100% sensitivity by the combined Doppler, but with only 48% sensitivity by the periorbital indirect test. The specific ability of both methods to identify non-stenotic carotid arteries (less than 50%) was similar at about 98%. Only the combined Doppler examination reliably differentiated various degrees of obstruction, comparable to that obtained with arteriography. Non-obstructive plaques could not be detected or excluded by either Doppler test. More refined methods will be necessary for their evaluation. Images PMID:6693913

  15. Cheek and periorbital peculiar discoid lupus erythematosus: rare clinical presentation mimicking tinea faciei, cutaneous granulomatous disease or blepharitis.

    PubMed

    Nakamura, Satoshi; Yamada, Tomoko; Umemoto, Naoka; Nakamura, Toshinobu; Wakatabi, Koji; Iida, Eri; Masaki, Masumi; Kakurai, Maki; Demitsu, Toshio

    2015-01-01

    We present clinically peculiar facial discoid lupus erythematosus (DLE) that mimicked tinea faciei. Although DLE is a chronic autoimmune dermatosis, it has a variety of rare clinical presentations, including periorbital DLE, comedonic DLE and hypertrophic DLE recently. In this case, a scaly, erythematous lesion on the eyelid and the central healed, mildly elevated, annularly distributed facial DLE mimicked tinea faciei, complicating our diagnosis. PMID:25969679

  16. Malignant hair follicle tumors of the periorbital region: A review of literature and suggestion of a management guideline.

    PubMed

    Sia, Paul Ikgan; Figueira, Edwin; Allende, Alexandra; Selva, Dinesh

    2016-06-01

    Malignant hair follicle tumors are rare skin adnexal malignancies that have a predilection for the head and neck region. They can be categorized into a number of different subtypes. Histologically, they are distinct from their benign counterpart. To the best of our knowledge, there is no extensive review of these malignancies, especially in the periorbital region. We aim to provide a literature review and a guideline for management of these malignant tumors in the periorbital region. Database from Medline, PubMed, Embase, and Google Scholar were consulted. A total of 16 cases from the literature on hair follicle malignancies in the periorbital region were included in this review. The clinical presentations, diagnostic patterns, investigations used, and best management approach of these tumors are discussed. The American Joint Committee on Cancer (AJCC) 7(th) edition carcinoma of the eyelid staging system was used to describe their behaviors. We recommend wide excision surgery and a close follow-up for these tumors. Tumors presenting with a late stage require work-up for distant metastasis and consideration for exenteration procedures. The role of radiotherapy and chemotherapy in this context is still uncertain.

  17. Malignant hair follicle tumors of the periorbital region: A review of literature and suggestion of a management guideline.

    PubMed

    Sia, Paul Ikgan; Figueira, Edwin; Allende, Alexandra; Selva, Dinesh

    2016-06-01

    Malignant hair follicle tumors are rare skin adnexal malignancies that have a predilection for the head and neck region. They can be categorized into a number of different subtypes. Histologically, they are distinct from their benign counterpart. To the best of our knowledge, there is no extensive review of these malignancies, especially in the periorbital region. We aim to provide a literature review and a guideline for management of these malignant tumors in the periorbital region. Database from Medline, PubMed, Embase, and Google Scholar were consulted. A total of 16 cases from the literature on hair follicle malignancies in the periorbital region were included in this review. The clinical presentations, diagnostic patterns, investigations used, and best management approach of these tumors are discussed. The American Joint Committee on Cancer (AJCC) 7(th) edition carcinoma of the eyelid staging system was used to describe their behaviors. We recommend wide excision surgery and a close follow-up for these tumors. Tumors presenting with a late stage require work-up for distant metastasis and consideration for exenteration procedures. The role of radiotherapy and chemotherapy in this context is still uncertain. PMID:27171562

  18. A recent case of periorbital necrotizing fasciitis--presentation to definitive reconstruction within an in-theater combat hospital setting.

    PubMed

    Casey, Kevin; Cudjoe, Peter; Green, J Marshall; Valerio, Ian L

    2014-07-01

    First described in 1924, necrotizing fasciitis (NF) is a rapidly progressing, severe suppurative infection of the superficial fascia, often associated with vascular thrombosis and necrosis of the overlying skin. Despite advances in medical therapy, the mortality remains high, with rates exceeding 25 to 50% in some studies. Early diagnosis and treatment is paramount in the management of this serious infection and should include wide surgical debridement and drainage of all necrotic tissues, coupled with aggressive parenteral antibiotics. This infectious process has been commonly associated with traumatic events in patients with compromised immune systems, diabetes, chronic steroid use, and alcoholism. The common microbacterial organisms associated with necrotizing fasciitis include Streptococcus pyogenes and Staphylococcus aureus and less commonly, facultative and anaerobic microorganisms. Most cases typically present in the extremities, trunk, and/or groin regions. Although this virulent soft tissue infection can occur within the face and neck areas, cases of isolated periorbital NF have been relatively uncommon. However, head and neck cases of NF have had high associated morbidity and mortality rates. In recent publications, the reported mortality rate for isolated periorbital NF was not insignificant, ranging from 8.5 to 12.5%. The prognosis, morbidity, and mortality rates will be greatly increased in those patients who present late in the infectious phase, have a delay in diagnosis and/or treatment, or who demonstrate extension of this virulent infection into the face, cervical, or sternal/mediastinal regions. An aggressive multimodal approach is required in treating periorbital necrotizing infection, with the main tenant remaining wide and adequate surgical debridement of affected tissues. This difficult clinical situation can create a subsequent challenge with respect to achieving good functional and cosmetic outcomes in those patients with periorbital NF

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

    PubMed

    Nakanishi, Haruka; Tono, Tetsuya; Ibusuki, Shoichiro

    2015-01-01

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

  20. Postoperative Submandibular Gland Swelling following Craniotomy under General Anesthesia

    PubMed Central

    Nakanishi, Haruka; Tono, Tetsuya; Ibusuki, Shoichiro

    2015-01-01

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

  1. 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.

  2. The Freestyle Facial Artery Perforator Flap for Reconstruction of Simultaneous Periorbital and Cheek Defects.

    PubMed

    Horta, Ricardo; Teixeira, Sergio; Nascimento, Ricardo; Silva, Alvaro; Amarante, Jose

    2016-07-01

    The reconstruction of defects involving the nasolabial, paranasal, and periorbital regions may be challenging, because they often involve more than one facial aesthetic unit, and can lead to functional problems. An average of 5 facial artery perforators of caliber >0.5 mm can be found above the mandible. A reference point for the location of the most constantly encountered perforator was suggested as being 1.5 cm lateral to the oral commissure, and at its same level in height or slightly inferior to the commissure. Based on injection studies, it is known that these perforators can supply an average area of 8 cm. The authors have extended the use of the freestyle perforator flap in a 87-year-old woman presented with an advanced melanoma of the paranasal area and nasolabial region (Breslow depth: 9 mm; Clark level V). Complete resection of the lesion with 3 cm oncological margins was performed. One-stage reconstruction with superior cosmetic results was achieved. The need for a perforator dissection is not necessarily a drawback, and classic concerns should be abandoned. The face is highly vascularized, and flap congestion is a rare event, usually a consequence of excessive pedicle trimming. Although technically more demanding, it should become one of the first reconstructive options when dealing with similar defects, if our results are confirmed in larger series. PMID:27391517

  3. Cavernous sinus thrombosis caused by a dental infection: a case report.

    PubMed

    Yeo, Gi-Sung; Kim, Hyun Young; Kim, HyunYoung; Kwak, Eun-Jung; Jung, Young-Soo; Park, Hyung-Sik; Jung, Hwi-Dong

    2014-08-01

    Cavernous sinus thrombosis not only presents with constitutional symptoms including fever, pain and swelling but also with specific findings such as proptosis, chemosis, periorbital swelling, and cranial nerve palsies. It is known to occur secondary to the spread of paranasal sinus infections in the nose, ethmoidal and sphenoidal sinuses. However, paranasal sinus infection of dental origin is rare. The following is a case of cavernous sinus thrombosis due to the spread of an abscess in the buccal and pterygomandibular spaces via buccal mucosal laceration. PMID:25247150

  4. A Comparative Study of Two Modalities, 4% Hydroquinone Versus 30% Salicylic Acid in Periorbital Hyperpigmentation and Assessment of Quality of Life Before and After Treatment

    PubMed Central

    Ranjan, Rashmi; Sarkar, Rashmi; Garg, Vijay Kumar; Gupta, Tanvi

    2016-01-01

    Background: Periorbital hyperpigmentation (POH) is a common hyperpigmentary problem of the face, which can be psychologically distressing and it can influence an individual's quality of life. However, this condition has received less attention in literature. Aims and Objectives: To study the clinico-etiological features and the effect of two therapeutic modalities on the quality of life in patients of POH before and after treatment. Materials and Methods: Fifty patients attending the outpatient clinic of Dermatology Department, with clinically evident POH were included. All patients were divided randomly into two groups of 25 each and one group was treated with 4% hydroquinone and another group with 30% salicylic acid for 12 weeks. Assessment with visual analog scale (VAS) was done at 4, 6, and 12 weeks, and outcome of the patients was analyzed statistically. Results: Majority of the cases, i.e. 26 (52%) were in the age group of 20–30 years. Females comprised 74% of the study population. On VAS, most of the patients showed mild improvement (10–30%) at 12 weeks of treatment in both the groups. Separately, both the treatments significantly improved the dermatological life quality index of the patients although there was no significant difference found between the two groups. Conclusion: POH is less responsive to standard treatments due to its multifactorial etiology and deposition of melanin in both dermis and epidermis. However, even the mild to moderate improvement in appearance can cause an improvement in the quality of life of the patients. PMID:27512187

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

    MedlinePlus

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

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

  7. Bilateral periorbital and cervicofacial emphysema following retinal surgery and fluid gas exchange in a case of inadvertent globe perforation

    PubMed Central

    Asnani, Haresh T; Mehta, Vinod C; Nair, Akshay Gopinathan; Jain, Vandana

    2015-01-01

    Surgical emphysema is defined as gas or air trapped in the subcutaneous tissue plane. Here, we report a rare case of bilateral periorbital and cervicofacial subcutaneous emphysema following a vitreoretinal surgery for inadvertent globe perforation during the administration of peribulbar anesthesia. This condition, although self-resolving when restricted to the subcutaneous plane has the potential to spread into deeper tissue planes such as the retropharyngeal space. The presence of crepitus helps to distinguish it from angioneurotic edema. Ophthalmologists must be sensitive to the fact that surgical emphysema can be a very rare, but possible complication of an intraocular surgery following globe perforation. PMID:26265649

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

    NASA Technical Reports Server (NTRS)

    Martin, S. F.; Feynman, J.

    1993-01-01

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

  9. 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

  10. 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.

  11. Malignant cerebral swelling following cranioplasty.

    PubMed

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

    2016-07-01

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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. Swelling-shrinkage measurements of bentonite using coupled environmental scanning electron microscopy and digital image analysis.

    PubMed

    Montes-H, G

    2005-04-01

    The swelling clays have been proposed as engineered barriers in geological disposal systems for waste because these materials are assumed to build a better impermeable zone around wastes by swelling. However, the swelling potential of soils is also considered a prevalent cause of damage to buildings and constructions. For these reasons, it is fundamental to investigate the physicochemical and mechanical behavior of swelling clays. In the current study, the swelling-shrinkage potential (aggregates scale) was estimated using an environmental scanning electron microscope (ESEM) coupled with a digital image analysis (DIA) program (Visilog). In fact, the isolated aggregates of raw and cation-exchanged bentonite were directly observed at different relative humidities in an ESEM chamber. Then the "Visilog" software was used to estimate the percent augmentation of the aggregate surface as a function of time and as a function of relative humidity. This estimation allows for the calculation of the swelling-shrinkage potential (%) of bentonite. Finally, a kinetic model of first order was tested to fit the kinetic experimental data of swelling-shrinkage potential. The results show that ESEM-DIA coupling can be a powerful method of estimating the swelling-shrinkage potential of expansive clays. In addition, the exponential models fit well with the kinetic experimental data. PMID:15752813

  18. 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.

  19. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-11-01

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

  20. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1990-11-01

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

  1. 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.

  2. Acquired, Idiopathic, Patterned Facial Pigmentation (AIPFP) Including Periorbital Pigmentation and Pigmentary Demarcation Lines on Face Follows the Lines of Blaschko on Face

    PubMed Central

    Sarma, Nilendu; Chakraborty, Sayantani; Bhattacharya, Sneha Ranjan

    2014-01-01

    Background: Acquired, non-nevoid, apparently idiopathic facial pigmentation are distributed over some specific locations like periorbital area, zygomatic area, malar area, root of nose, perioral and mandibular area. Periorbital pigmentation is the most well known entity in this group. These are bilaterally distributed homogenously diffuse gray to dark gray or slate-gray colored patches showing progressive intensification of pigmentation. These are often considered as physiologic or constitutional pigmentation. Some portions of the margins of these patches were described previously as pigmentary demarcation line (PDL- F, G, H). Aim: To analyze the distributional patterns of acquired, apparently idiopathic facial pigmentations and to evaluate the etiologic aspects of these conditions. Materials and Methods: Spatial patterns, distribution, and orientation were analyzed among 187 individuals with idiopathic non-nevoid, facial pigmentation. Observed patterns were compared with various pigmentary nevi and Blaschko's lines on face. Results: It was found that most of the idiopathic facial pigmentary alterations including periorbital pigmentation and PDL on face had specific patterned distribution that had high similarity to that of the pigmentary nevi and Blaschko's lines on face. Conclusion: It is hypothesized here that phenotypic expression of acquired patterned pigmentation (AIFPFP) is due to genetically determined increased pigmentary functional activity to various known and unknown yet natural factors like UV rays and aging. Mosaicism was a definite possibility. We also consider that the patterns actually reflected the normal patterns of embryological human pigmentation on face. PMID:24470659

  3. Climatology of Global Swell-Atmosphere Interaction

    NASA Astrophysics Data System (ADS)

    Semedo, Alvaro

    2016-04-01

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

  4. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1991-01-01

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

  5. Swelling kinetics of tea in hot water.

    PubMed

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

    2016-01-01

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

  6. Swelling kinetics of tea in hot water.

    PubMed

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

    2016-01-01

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

  7. Influence of binary swelling solvents: Mechanism of action

    SciTech Connect

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

    1995-12-31

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

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

    NASA Astrophysics Data System (ADS)

    Kanguzhin, Baltabek; Zhapsarbayeva, Lyailya

    2016-08-01

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

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

    NASA Astrophysics Data System (ADS)

    Johnson, Lee James

    2001-08-01

    then shown to correlate to mitochondrial swelling, as observed with electron microscopy. The system is finally used to study mitochondrial and cellular swelling. Evidence of the susceptibility of certain hippocampal regions, CA1 and the dentate gyrus, to exhibit mitochondrial swelling as the result of oxygen and glucose deprivation is presented. In addition, for the first time, the time course of mitochondrial swelling is seen. Finally, experiments with scatter imaging and measurement of nitric oxide with carbon fiber electrodes demonstrate a clear link between nitric oxide and cellular swelling. A potential mechanism of the action of nitric oxide is evaluated. Nitric oxide appears to act to cause cellular swelling without the release of glutamate. The use of targeted nitric oxide inhibitors may be useful for the reduction of edema.

  10. Monitoring austral and cyclonic swells in the "Iles Eparses" (Mozambique channel) from microseismic noise

    NASA Astrophysics Data System (ADS)

    Barruol, Guilhem; Davy, Céline; Fontaine, Fabrice R.; Schlindwein, V.; Sigloch, K.

    2016-04-01

    We deployed five broadband three-components seismic stations in the Iles Eparses in the south-west Indian Ocean and on Mayotte Island, between April 2011 and January 2014. These small and remote oceanic islands suffer the effects of strong ocean swells that affect their coastal environments but most islands are not instrumented by wave gauges to characterize the swells. However, wave action on the coast causes high levels of ground vibrations in the solid earth, so-called microseismic noise. We use this link between the solid earth and ocean wave activity to quantify the swells locally. Spectral analyses of the continuous seismic data show clear peaks in the 0.05-0.10 Hz frequency band (periods between 10 and 20 s), corresponding to the ocean wave periods of the local swells. We analyze an example of austral swell occurring in August 2013 and a cyclonic event (Felleng) that developed in January 2013, and quantify the ground motion at each station induced by these events. In both cases, we find a linear polarization in the horizontal plane with microseismic amplitude directly correlated to the swell height (as predicted by the global swell model WaveWatchIII), and a direction of polarization close to the predicted swell propagation direction. Although this analysis has not been performed in real time, it demonstrates that terrestrial seismic stations can be efficiently used as wave gauges, and are particularly well suited for quantifying extreme swell events. This approach may therefore provide useful and cheaper alternatives to wave buoys for monitoring swells and the related environmental processes such as beach erosion or coral reef damages.

  11. 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.

  12. 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.

  13. 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.

  14. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1991-08-01

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

  15. Morphing of geometric composites via residual swelling.

    PubMed

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

    2015-08-01

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

  16. Swelling and Contraction of Corn Mitochondria 1

    PubMed Central

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

    1966-01-01

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

  17. Swell-Dissipation Function for Wave Models

    NASA Astrophysics Data System (ADS)

    Babanin, A.

    2012-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Althans, Daniel; Langenbach, Kai; Enders, Sabine

    2012-06-01

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

  19. Stress-enhanced swelling of metal during irradiation

    SciTech Connect

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

    1980-04-01

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

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

    PubMed

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

    2016-08-01

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

  1. 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

  2. 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

  3. Swelling of pH-sensitive hydrogels.

    PubMed

    Drozdov, A D; deClaville Christiansen, J

    2015-02-01

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

  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. 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.

  6. 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

  7. Swelling of plasma-polymerized tetrafluoroethylene films

    SciTech Connect

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

    1991-11-25

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

  8. Subconjuctival Loa loa with Calabar swelling.

    PubMed

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

    2008-08-01

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

  9. Fibromatosis Colli - A Rare Cytological Diagnosis In Infantile Neck Swellings

    PubMed Central

    Jetley, Sujata; Jairajpuri, Zeeba; Husain, Musharraf

    2014-01-01

    Fibromatosis colli or sternocleidomastoid tumour is a rare cause of benign neck mass in infants. It is a self limiting fibroblastic lesion usually presenting with torticollis and a history of birth trauma.It is one of the few causes in which Fine Needle Aspiration Cytology (FNAC) is indicated in a neonate to confirm the diagnosis and to differentiate it from other congenital, inflammatory and neoplastic causes. FNAC provides a rapid, cost-effective, reliable, non invasive method of diagnosis resulting in conservative management of these lesions. We present two interesting cases of neck swelling in infants where FNAC performed as the first diagnostic procedure was instrumental in establishing the diagnosis of fibromatosis colli thus avoiding unnecessary surgical intervention. PMID:25584233

  10. 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

  11. Size distribution of black spot defects and their contribution to swelling in irradiated SiC

    NASA Astrophysics Data System (ADS)

    Tyburska-Püschel, B.; Zhai, Y.; He, L.; Liu, C.; Boulle, A.; Voyles, P. M.; Szlufarska, I.; Sridharan, K.

    2016-08-01

    Experimental and modeling efforts were combined to investigate the role of black spot defects (BSD) in swelling of carbon- and krypton-irradiated 4H-SiC. Samples were exposed to conditions favoring BSD formation: irradiation at temperatures 600-950 °C and damage levels of 0.4-0.8 dpa. The maximum XRD swelling values, corrected for the effect of the rigid substrate, of 0.58% for C and 0.75% for Kr-irradiation were measured at the lowest irradiation temperature of 600 °C and decreased with increasing temperature. The swelling values estimated from TEM are on the same order of magnitude, but usually 40-70% lower than those measured by XRD. The contribution of BSDs to the overall swelling is 62% and the remainder of the swelling is caused by isolated point defects. The obtained results contribute to understanding of what defect types account for swelling and how their concentration evolves with the irradiation temperature and damage level.

  12. Pinch and swell structures: evidence for brittle-viscous behaviour in the middle crust

    NASA Astrophysics Data System (ADS)

    Gardner, R.; Piazolo, S.; Daczko, N.

    2015-04-01

    The flow properties of middle to lower crustal rocks are commonly represented by viscous flow. However, examples of pinch and swell structures found in a mid-crustal high strain zone at St. Anne Point (Fiordland, New Zealand) suggest pinch and swell structures are initiated by brittle failure of the more competent layer in conjunction with material softening. On this basis we develop a flexible numerical model using brittle-viscous flow where Mohr-Coulomb failure is utilised to initiate pinch and swell structure development. Results show that pinch and swell structures develop in a competent layer in both Newtonian and non-Newtonian flow provided the competent layer has enough viscosity contrast and initially fails brittlely. The degree of material softening after initial failure is shown to impact pinch and swell characteristics with high rates of material softening causing the formation of thick necks between swells by limiting the successful localisation of strain. The flow regime and yielding characteristics of the matrix do not impact pinch and swell structure formation itself, so long as the matrix is less competent. To aid analysis of the structures and help derive the flow properties of rocks in the field, we define three stages of pinch and swell development and offer suggestions for measurements to be made in the field. Our study suggests that Mohr-Coulomb behaviour combined with viscous flow is an appropriate way to represent the heterogeneous rocks of the middle to lower crust. This type of mid-crustal rheological behaviour has significant influence on the localization of strain at all scales. For example, inclusion of Mohr-Coulomb brittle failure with viscous flow in just some mid-crustal layers within a crustal scale model will result in strain localisation throughout the whole crustal section allowing the development of through-going high strain structures from the upper crust into the middle and lower crust. This localization then has a significant

  13. Acute unilateral parotid gland swelling after lateral decubitus position under general anesthesia.

    PubMed

    Postaci, Aysun; Aytac, Ismail; Oztekin, Cetin Volkan; Dikmen, Bayazit

    2012-07-01

    Acute swelling of the parotid gland after general anesthesia (commonly known as anesthesia mumps or acute postoperative sialadenitis) is a rare but declared complication of anesthesia. The etiology is not clear, but some possible causes such as obstruction of glandular excretory ducts caused by patient position and increase in the viscosity of the saliva because of acute dehydratation and/or medications like atropin have been proposed. We report a swelling in the left preauricular and postauricular region extending to the angle of the mandibule in a 35-year-old patient after left lateral decubitus position for laparoscopic nephrectomy.

  14. Acute unilateral parotid gland swelling after lateral decubitus position under general anesthesia

    PubMed Central

    Postaci, Aysun; Aytac, Ismail; Oztekin, Cetin Volkan; Dikmen, Bayazit

    2012-01-01

    Acute swelling of the parotid gland after general anesthesia (commonly known as anesthesia mumps or acute postoperative sialadenitis) is a rare but declared complication of anesthesia. The etiology is not clear, but some possible causes such as obstruction of glandular excretory ducts caused by patient position and increase in the viscosity of the saliva because of acute dehydratation and/or medications like atropin have been proposed. We report a swelling in the left preauricular and postauricular region extending to the angle of the mandibule in a 35-year-old patient after left lateral decubitus position for laparoscopic nephrectomy. PMID:23162409

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  16. Effect of grain morphology on gas bubble swelling in UMo fuels - A 3D microstructure dependent Booth model

    NASA Astrophysics Data System (ADS)

    Hu, Shenyang; Burkes, Douglas; Lavender, Curt A.; Joshi, Vineet

    2016-11-01

    A three dimensional microstructure dependent swelling model is developed for studying the fission gas swelling kinetics in irradiated nuclear fuels. The model is extended from the Booth model [1] in order to investigate the effect of heterogeneous microstructures on gas bubble swelling kinetics. As an application of the model, the effect of grain morphology, fission gas diffusivity, and spatially dependent fission rate on swelling kinetics are simulated in UMo fuels. It is found that the decrease of grain size, the increase of grain aspect ratio for the grain having the same volume, and the increase of fission gas diffusivity (fission rate) cause the increase of swelling kinetics. Other heterogeneities such as second phases and spatially dependent thermodynamic properties including diffusivity of fission gas, sink and source strength of defects could be naturally integrated into the model to enhance the model capability.

  17. 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.

  18. Stress Singularities in Swelling Soft Solids

    NASA Astrophysics Data System (ADS)

    Goriely, Alain; Weickenmeier, Johannes; Kuhl, Ellen

    2016-09-01

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

  19. Morphological effect on swelling behaviour of hydrogel

    NASA Astrophysics Data System (ADS)

    Yacob, Norzita; Hashim, Kamaruddin

    2014-02-01

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

  20. Molecular accessibility in solvent swelled coals

    SciTech Connect

    Kispert, L.D.

    1993-02-01

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

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  3. Controlling morphology in swelling-induced wrinkled surfaces

    NASA Astrophysics Data System (ADS)

    Breid, Derek Ronald

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

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

    PubMed

    Bell, C L; Peppas, N A

    1996-01-01

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

  5. Shape instability on swelling of a stretched nematic elastomer filament.

    PubMed

    Cheewaruangroj, N; Terentjev, E M

    2015-10-01

    Liquid crystalline elastomers combine the ordering properties of liquid crystals with elasticity of crosslinked polymer networks. In monodomain (permanently aligned) elastomers, altering the orientational (nematic) order causes changes in the equilibrium sample length, which is the basis of the famous effect of large-amplitude reversible mechanical actuation. The stimulus for this effect could be a change in temperature, or illumination by light in photosensitized elastomers, but equally the nematic order changes by mixing with a solvent. This work theoretically investigates a competition between the spontaneous contraction on swelling of a monodomain nematic elastomer and the externally imposed stretching. We find that this competition leads to bistability in the system and allows a two-phase separation between a nematic state with lower swelling and an isotropic state with higher solvent concentration. We calculated the conditions in which the instability occurs as well as the mechanical and geometric parameters of equilibrium states. Being able to predict how this instability arises will provide opportunities for exploiting nematic elastomer filaments.

  6. Quantitative analyses of extrudate swell for polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Kejian; Sun, Chongxiao

    2009-07-01

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

  7. Mineralogy-swelling potential relationships for expansive shales

    USGS Publications Warehouse

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

    2000-01-01

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

  8. [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.

  9. Swelling induced by alpha decay in monazite and zirconolite ceramics: A XRD and TEM comparative study

    NASA Astrophysics Data System (ADS)

    Deschanels, X.; Seydoux-Guillaume, A. M.; Magnin, V.; Mesbah, A.; Tribet, M.; Moloney, M. P.; Serruys, Y.; Peuget, S.

    2014-05-01

    Zirconolite and monazite matrices are potential ceramics for the containment of actinides (Np, Cm, Am, Pu) which are produced over the reprocessing of spent nuclear fuel. Actinides decay mainly through the emission of alpha particles, which in turn causes most ceramics to undergo structural and textural changes (amorphization and/or swelling). In order to study the effects of alpha decays on the above mentioned ceramics two parallel approaches were set up. The first involved the use of an external irradiation source, Au, which allowed the deposited recoil energy to be simulated. The second was based on short-lived actinide doping with 238Pu, (i.e. an internal source), via the incorporation of plutonium oxide into both the monazite and zirconolite structures during synthesis. In both types of irradiation experiments, the zirconolite samples became amorphous at room temperature with damage close to 0.3 dpa; corresponding to a critical dose of 4 × 1018 α g-1 (i.e. ∼1.3 × 1021 keV cm-3). Both zirconolite samples also showed the same degree of macroscopic swelling at saturation (∼6%), with ballistic processes being the predominant damaging effect. In the case of the monazite however, the macroscopic swelling and amorphization were dependent on the nature of the irradiation. Externally, (Au), irradiated samples became amorphous while also demonstrating a saturation swelling of up to 8%. In contrast to this, the swelling of the 238Pu doped samples was much smaller at ∼1%. Also, unlike the externally (Au) irradiated monazite these 238Pu doped samples remained crystalline up to 7.5 × 1018 α g-1 (0.8 dpa). XRD, TEM and swelling measurements were used to fully characterize and interpret this behavior. The low swelling and the conservation of the crystalline state of 238Pu doped monazite samples indicates that alpha annealing took place within this material.

  10. Urinary retention secondary to acute vasculitic penile swelling in a pediatric patient.

    PubMed

    Farkas, Nicholas; Black, John; Gupta, Ashish

    2016-03-01

    Acute urinary retention secondary to vasculitic penile swelling in children is extremely rare. Henoch-Schönlein purpura is a self-limiting IgA-mediated cutaneous vasculitis, which can cause soft tissue edema. Acute urinary retention requires urgent intervention to prevent obstructive uropathy. Suprapubic catheterization provides an effective management strategy in the emergency setting. PMID:27014447

  11. 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.

  12. Swelling transition of a clay induced by heating.

    PubMed

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

    2012-01-01

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

  13. Swelling transition of a clay induced by heating.

    PubMed

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Kimoto, T.; Shiraishi, H.

    1985-07-01

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

  15. 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.

  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. Effects of tunneling on groundwater flow and swelling of clay-sulfate rocks

    NASA Astrophysics Data System (ADS)

    Butscher, Christoph; Einstein, Herbert H.; Huggenberger, Peter

    2011-11-01

    Swelling of clay-sulfate rocks is a major threat in tunneling. It is triggered by the transformation of the sulfate mineral anhydrite into gypsum as a result of water inflow in anhydrite-containing layers after tunnel excavation. The present study investigates the hydraulic effects of tunneling on groundwater flow and analyzes how hydraulic changes caused by excavation lead to water inflow into anhydrite-containing layers in the tunnel area. Numerical groundwater models are used to conduct scenario simulations that allow one to relate hydrogeological conditions to rock swelling. The influence of the topographic setting, the excavation-damaged zone around the tunnel, the sealing effect of the tunnel liner, and the geological configuration are analyzed separately. The analysis is performed for synthetic situations and is complemented by a case study from a tunnel in Switzerland. The results illustrate the importance of geological and hydraulic information when assessing the risk of swelling at an actual site.

  18. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-05-29

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

  19. Molecular accessibility in solvent swelled coal

    SciTech Connect

    Kispert, L.D.

    1992-08-01

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

  20. Bimodal swelling responses in microgel thin films.

    PubMed

    Sorrell, Courtney D; Lyon, L Andrew

    2007-04-26

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

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

    PubMed

    Ghorpade, Ashok

    2015-01-01

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

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

    PubMed

    Mohamed Mokhtarudin, M J; Payne, S J

    2015-05-01

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

  3. Irradiation creep relaxation of void swelling-driven stresses

    NASA Astrophysics Data System (ADS)

    Hall, M. M.

    2013-01-01

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

  4. 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.

  5. 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

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

    SciTech Connect

    Doetschman, D.C.

    1992-11-06

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

  7. A simple model for the swelling of polymer networks

    SciTech Connect

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

    1993-07-15

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

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

    NASA Astrophysics Data System (ADS)

    Serafeimidis, Konstantinos

    2015-04-01

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

  9. 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

  10. Clay swelling — A challenge in the oilfield

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

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

  13. Disease prevalence and snail predation associated with swell-generated damage on the threatened coral, Acropora palmata (Lamarck)

    USGS Publications Warehouse

    Bright, Allan J.; Rogers, Caroline S.; Brandt, Marilyn E.; Muller, Erinn; Smith, Tyler B.

    2016-01-01

    Disturbances such as tropical storms cause coral mortality and reduce coral cover as a direct result of physical damage. Storms can be one of the most important disturbances in coral reef ecosystems, and it is crucial to understand their long-term impacts on coral populations. The primary objective of this study was to determine trends in disease prevalence and snail predation on damaged and undamaged colonies of the threatened coral species, Acropora palmata, following an episode of heavy ocean swells in the US Virgin Islands (USVI). At three sites on St. Thomas and St. John, colonies of A. palmata were surveyed monthly over 1 year following a series of large swells in March 2008 that fragmented 30–93% of colonies on monitored reefs. Post-disturbance surveys conducted from April 2008 through March 2009 showed that swell-generated damage to A. palmata caused negative indirect effects that compounded the initial direct effects of physical disturbance. During the 12 months after the swell event, white pox disease prevalence was 41% higher for colonies that sustained damage from the swells than for undamaged colonies (df = 207, p = 0.01) with greatest differences in disease prevalence occurring during warm water months. In addition, the corallivorous snail, Coralliophila abbreviata, was 46% more abundant on damaged corals than undamaged corals during the 12 months after the swell event (df = 207, p = 0.006).

  14. Swelling of two-dimensional polymer rings by trapped particles.

    PubMed

    Haleva, E; Diamant, H

    2006-09-01

    The mean area of a two-dimensional Gaussian ring of N monomers is known to diverge when the ring is subject to a critical pressure differential, p c ~ N -1. In a recent publication (Eur. Phys. J. E 19, 461 (2006)) we have shown that for an inextensible freely jointed ring this divergence turns into a second-order transition from a crumpled state, where the mean area scales as [A]~N-1, to a smooth state with [A]~N(2). In the current work we extend these two models to the case where the swelling of the ring is caused by trapped ideal-gas particles. The Gaussian model is solved exactly, and the freely jointed one is treated using a Flory argument, mean-field theory, and Monte Carlo simulations. For a fixed number Q of trapped particles the criticality disappears in both models through an unusual mechanism, arising from the absence of an area constraint. In the Gaussian case the ring swells to such a mean area, [A]~ NQ, that the pressure exerted by the particles is at p c for any Q. In the freely jointed model the mean area is such that the particle pressure is always higher than p c, and [A] consequently follows a single scaling law, [A]~N(2) f (Q/N), for any Q. By contrast, when the particles are in contact with a reservoir of fixed chemical potential, the criticality is retained. Thus, the two ensembles are manifestly inequivalent in these systems. PMID:17028790

  15. 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

  16. Analysis and prediction of ocean swell using instrumented buoys

    NASA Technical Reports Server (NTRS)

    Mettlach, Theodore; Wang, David; Wittmann, Paul

    1994-01-01

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

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

    PubMed

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

    2016-08-01

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

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

    PubMed

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

    2016-08-01

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

  19. Skeletogenesis in the swell shark Cephaloscyllium ventriosum.

    PubMed

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

    2007-05-01

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

  20. 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

  1. 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.

  2. Modeling Coal Matrix Shrinkage and Differential Swelling with CO2 Injection for Enhanced Coalbed Methane Recovery and Carbon Sequestration Applications

    SciTech Connect

    L. J. Pekot; S. R. Reeves

    2002-03-31

    Matrix shrinkage and swelling can cause profound changes in porosity and permeability of coalbed methane reservoirs during depletion or when under CO{sub 2} injection processes, with significant implication for primary or enhanced methane recovery. Two models that are used to describe these effects are discussed. The first was developed by Advanced Resources International (ARI) and published in 1990 by Sawyer, et al. The second model was published by Palmer and Mansoori in 1996. This paper shows that the two provide equivalent results for most applications. However, their differences in formulation cause each to have relative advantages and disadvantages under certain circumstances. Specifically, the former appears superior for undersaturated coalbed methane reservoirs while the latter would be better if a case is found where matrix swelling is strongly disproportional to gas concentration. Since its presentation in 1996, the Palmer and Mansoori model has justifiably received much critical praise. However, the model developed by ARI for the COMET reservoir simulation program has been in use since 1990, and has significant advantages in certain settings. A review of data published by Levine in 1996 reveals that carbon dioxide causes a greater degree of coal matrix swelling compared to methane, even when measured on a unit of concentration basis. This effect is described in this report as differential swelling. Differential swelling may have important consequences for enhanced coalbed methane and carbon sequestration projects. To handle the effects of differential swelling, an extension to the matrix shrinkage and swelling model used by the COMET simulator is presented and shown to replicate the data of Levine. Preliminary field results from a carbon dioxide injection project are also presented in support of the extended model. The field evidence supports that considerable changes to coal permeability occur with CO{sub 2} injection, with significant implication for

  3. 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

  4. Ion irradiation studies on the void swelling behavior of a titanium modified D9 alloy

    NASA Astrophysics Data System (ADS)

    Balaji, S.; Mohan, Sruthi; Amirthapandian, S.; Chinnathambi, S.; David, C.; Panigrahi, B. K.

    2015-12-01

    The sensitivity of Positron Annihilation Spectroscopy (PAS) for probing vacancy defects and their environment is well known. Its applicability in determination of swelling and the peak swelling temperature was put to test in our earlier work on ion irradiated D9 alloys [1]. Upon comparison with the peak swelling temperature determined by conventional step height measurements it was found that the peak swelling temperature determined using PAS was 50 K higher. It was conjectured that the positrons trapping in the irradiation induced TiC precipitation could have caused the shift. In the present work, D9 alloys have been implanted with 100 appm helium ions and subsequently implanted with 2.5 MeV Ni ions up to peak damage of 100 dpa. The nickel implantations have been carried out through a range of temperatures between 450 °C and 650 °C. The evolution of cavities and TiC precipitates at various temperatures has been followed by TEM and this report provides an experimental verification of the conjecture.

  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. The effects of temperature and inhibitors on HCO3-stimulated swelling and ion uptake of monkey cerebral cortex.

    PubMed

    Bourke, R S; Kimelberg, H K; Nelson, L R

    1976-03-26

    In the presence of high concentrations of K+, additions of HCO3- as low as 0.35 mM caused a 23% increase in swelling, and concomitant increases in the chloride content of incubating monkey cerebrocortical slices. The uptake of chloride was accompanied by increased uptake of sodium and was highly temperature dependent, showing a marked activation at approximately 30 degrees C. A similar temperature activation was also found for a Mg2+-dependent, HCO3-stimulated ATPase activity in monkey cerebral cortex, consistent with a possible role for this enzyme in the K+ and HCO3-dependent swelling process and its associated ion movements. K+-dependent, HCO3-stimulated cerebrocortical tissue swelling with uptake of Na+ and Cl- was inhibited by acetazolamide indicating that carbonic anhydrase was also involved. The addition of ouabain also inhibited swelling and K+ and Cl- uptake at low concentrations, but led to increased swelling at higher concentrations ( greater than 10 mum). A similar biphasic effect on swelling was also seen following addition of ethacrynic acid. PMID:130962

  7. Hyperspectral laboratory and airborne measurements as tools for local mapping of swelling soils in Orléans area (France)

    NASA Astrophysics Data System (ADS)

    Grandjean, Gilles; Dufrechou, Gregory; Hohmann, Audrey

    2013-04-01

    Swelling soils contain clay minerals that change volume with water content and cause extensive and expensive damage on infrastructures. Based on spatial distribution of infrastructure damages and existing geological maps, the Bureau de Recherches Géologiques et Minières (BRGM, the French Geological Survey) published in 2010 a 1:50 000 swelling hazard map of France. This map indexes the territory to low, intermediate, or high swell susceptibility, but does not display smallest and isolated clays lithologies. At local scale, identification of clay minerals and characterization of swell potential of soils using conventional soil analysis (DRX, chemical, and geotechnical analysis) are slow, expensive, and does not permit integrated measurements. Shortwave infrared (SWIR: 1100-2500 nm) spectral domains are characterized by significant spectral absorption bands that provide an underused tool for estimate the swell potential of soils. Reflectance spectroscopy, using an ASD Fieldspec Pro spectrometer, permits a rapid and less expensive measurement of soil reflectance spectra in the field and laboratory. In order to produce high precision map of expansive soils, the BRGM aims to optimize laboratory reflectance spectroscopy for mapping swelling soils. Geotechnical use of laboratory reflectance spectroscopy for local characterization of swell potential of soils could be assessable from an economical point of view. A new high resolution airborne hyperspectral survey (covering ca. 280 km², 380 channels ranging from 400 to 2500 nm) located at the W of Orléans (Loiret, France) will also be combined with field and laboratory measurements to detect and map swelling soils.

  8. A solitary facial nodular swelling - A case report of intramuscular cysticercosis in buccinator muscle

    PubMed Central

    Dysanoor, Sujatha; Pol, Jyoti

    2013-01-01

    Taenia solium, the larvae of pork tapeworm can cause the parasitic infection known as cysticercosis. It is commonly seen in developing countries. The condition rarely involves orofacial region and represents a difficulty in clinical diagnosis. We present a case report of a healthy middle aged female patient who had a painless swelling on right side of face. The ultrasound examination revealed an intramuscular cysticercosal cyst.

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

    PubMed

    Andersson, M; Axelsson, A; Zacchi, G

    1998-01-01

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

  10. Lethal liquorice lollies (liquorice abuse causing pseudohyperaldosteronism).

    PubMed

    Robles, B J Flores; Sandoval, A R Hurtarte; Dardon, J D Penate; Blas, C Alonso

    2013-09-19

    A 47-year-old woman was admitted to the emergency department with a history of asthenia, periorbital and lower limbs oedema, associated with hypokalaemia and increased blood pressure levels. Metabolic and renal causes were initially investigated as thyroid disease, Cushing syndrome and tubulopathies were excluded during the first week of admission. However, further questioning of the patient, revealed that she had been consuming several sachets of raw liquorice lollies (ignored amount) obtained from a herbalist a month ago. Based on the history and clinical findings, liquorice poisoning was highly suspected; an apparent mineralocorticoid excess secondary to ingestion of liquorice. Afterwards, levels of aldosterone and plasma renin activity were measured and found low 3 weeks later; therefore, our clinical suspicion was established. During the patient's stay at the hospital, liquorice was stopped and potassium supplements were started. Subsequently, a week after, the patient fully recovered without any significant sequelae.

  11. 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.

  12. Influence of Shrinkage and Swelling Properties of Coal on Geologic Sequestration of Carbon Dioxide

    SciTech Connect

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

    2007-05-01

    The potential for enhanced methane production and geologic sequestration of carbon dioxide in coalbeds needs to be evaluated before large-scale sequestration projects are undertaken. Geologic sequestration of carbon dioxide in deep unmineable coal seams with the potential for enhanced coalbed methane production has become a viable option to reduce greenhouse gas emissions. The coal matrix is believed to shrink during methane production and swell during the injection of carbon dioxide, causing changes in tlie cleat porosity and permeability of the coal seam. However, the influence of swelling and shrinkage, and the geomechanical response during the process of carbon dioxide injection and methane recovery, are not well understood. A three-dimensional swelling and shrinkage model based on constitutive equations that account for the coupled fluid pressure-deformation behavior of a porous medium was developed and implemented in an existing reservoir model. Several reservoir simulations were performed at a field site located in the San Juan basin to investigate the influence of swelling and shrinkage, as well as other geomechanical parameters, using a modified compositional coalbed methane reservoir simulator (modified PSU-COALCOMP). The paper presents numerical results for interpretation of reservoir performance during injection of carbon dioxide at this site. Available measured data at the field site were compared with computed values. Results show that coal swelling and shrinkage during the process of enhanced coalbed methane recovery can have a significant influence on the reservoir performance. Results also show an increase in the gas production rate with an increase in the elastic modulus of the reservoir material and increase in cleat porosity. Further laboratory and field tests of the model are needed to furnish better estimates of petrophysical parameters, test the applicability of thee model, and determine the need for further refinements to the mathematical

  13. 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.

  14. Molecular accessibility in solvent swelled coal. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1992-11-01

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

  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. PMID:27401424

  16. Swelling and Contraction of Phaseolus Hypocotyl Mitochondria 1

    PubMed Central

    Earnshaw, M. J.; Truelove, B.

    1968-01-01

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

  17. 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...

  18. 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

  19. 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.

  20. 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.

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

    SciTech Connect

    Kispert, L.D.

    1991-12-31

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

  2. 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

  3. Disassembly of actin structures by nanosecond pulsed electric field is a downstream effect of cell swelling.

    PubMed

    Pakhomov, Andrei G; Xiao, Shu; Pakhomova, Olga N; Semenov, Iurii; Kuipers, Marjorie A; Ibey, Bennett L

    2014-12-01

    Disruption of the actin cytoskeleton structures was reported as one of the characteristic effects of nanosecond-duration pulsed electric field (nsPEF) in both mammalian and plant cells. We utilized CHO cells that expressed the monomeric fluorescent protein (mApple) tagged to actin to test if nsPEF modifies the cell actin directly or as a consequence of cell membrane permeabilization. A train of four 600-ns pulses at 19.2 kV/cm (2 Hz) caused immediate cell membrane poration manifested by YO-PRO-1 dye uptake, gradual cell rounding and swelling. Concurrently, bright actin features were replaced by dimmer and uniform fluorescence of diffuse actin. To block the nsPEF-induced swelling, the bath buffer was isoosmotically supplemented with an electropore-impermeable solute (sucrose). A similar addition of a smaller, electropore-permeable solute (adonitol) served as a control. We demonstrated that sucrose efficiently blocked disassembly of actin features by nsPEF, whereas adonitol did not. Sucrose also attenuated bleaching of mApple-tagged actin in nsPEF-treated cells (as integrated over the cell volume), although did not fully prevent it. We conclude that disintegration of the actin cytoskeleton was a result of cell swelling, which, in turn, was caused by cell permeabilization by nsPEF and transmembrane diffusion of solutes which led to the osmotic imbalance. PMID:24507565

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

    PubMed

    Xu, Wenhai; Que Hee, Shane S

    2008-01-01

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

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

    PubMed

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

    2010-11-01

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

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

    PubMed

    Xu, Wenhai; Que Hee, Shane S

    2008-01-01

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

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

    Bodkin, PA; Labram, EK; Shetty, A

    2013-01-01

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

  9. Unusual case of focal neck swelling: Phlebectasia of internal jugular vein with intracranial extension

    PubMed Central

    Malik, Virender; Kumari, Abha; Murthy, TVSP

    2015-01-01

    Internal jugular vein (IJV) phlebectasia is rare in occurrence and is frequently misdiagnosed and managed inappropriately. It commonly presents as a unilateral neck swelling which typically increases in size with valsalva maneuver. Although, the most common cause of a focal neck swelling, which increases in size with valsalva maneuver is laryngocele, the possibility of phlebectasia of IJV should always be borne in mind, especially in child. Owing to the rarity of this condition, a high index of suspicion is required to recognize the same and managed appropriately. We present a case of phlebectasia of the right IJV with intracranial extension and discuss its management. The case is being reported in view of its clinical rarity (the intracranial extension being extremely rare) and to highlight the available management strategies. PMID:25664271

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

    PubMed

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

    2015-01-01

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

  11. Model for incorporating fuel swelling and clad shrinkage effects in diffusion theory calculations (LWBR Development Program)

    SciTech Connect

    Schick, W.C. Jr.; Milani, S.; Duncombe, E.

    1980-03-01

    A model has been devised for incorporating into the thermal feedback procedure of the PDQ few-group diffusion theory computer program the explicit calculation of depletion and temperature dependent fuel-rod shrinkage and swelling at each mesh point. The model determines the effect on reactivity of the change in hydrogen concentration caused by the variation in coolant channel area as the rods contract and expand. The calculation of fuel temperature, and hence of Doppler-broadened cross sections, is improved by correcting the heat transfer coefficient of the fuel-clad gap for the effects of clad creep, fuel densification and swelling, and release of fission-product gases into the gap. An approximate calculation of clad stress is also included in the model.

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

    PubMed

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

    1989-02-10

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

  13. Cytological diagnosis of bancroftian filariasis presented as a subcutaneous swelling in the cubital fossa: an unusual presentation.

    PubMed

    Pandey, Pinki; Dixit, Alok; Chandra, Subrat; Tanwar, Aparna

    2015-04-01

    Filariasis is a disabling parasitic disease and the prevalence of lymphatic filariasis caused by Wuchereria bancrofti is quite high in India. However, W. bancrofti presenting as a subcutaneous swelling and a demonstration of microfilariae in cytological smears from upper extremity lesions is extremely rare. We report a case of 20-year-old male who presented with a small subcutaneous swelling near medial aspect of the left cubital fossa. The wet mount preparation showed many motile microfilariae. Cytology smears revealed a large number of sheathed microfilariae with the tail tip free of nucleus, identified as W. bancrofti without significant inflammatory cell infiltrate. Indirect ELISA was highly positive for specific recombinant W. bancrofti filarial antigen (WL-L2). The role of cytology cannot be underestimated in clinically unanticipated cases of bancroftian filariasis, especially with the amicrofilaremic state. Filariasis should always be considered in the differential diagnosis during cytological evaluation of any swelling, especially in endemic areas. PMID:26634138

  14. Cytological diagnosis of bancroftian filariasis presented as a subcutaneous swelling in the cubital fossa: an unusual presentation

    PubMed Central

    Pandey, Pinki; Dixit, Alok; Chandra, Subrat; Tanwar, Aparna

    2015-01-01

    Filariasis is a disabling parasitic disease and the prevalence of lymphatic filariasis caused by Wuchereria bancrofti is quite high in India. However, W. bancrofti presenting as a subcutaneous swelling and a demonstration of microfilariae in cytological smears from upper extremity lesions is extremely rare. We report a case of 20-year-old male who presented with a small subcutaneous swelling near medial aspect of the left cubital fossa. The wet mount preparation showed many motile microfilariae. Cytology smears revealed a large number of sheathed microfilariae with the tail tip free of nucleus, identified as W. bancrofti without significant inflammatory cell infiltrate. Indirect ELISA was highly positive for specific recombinant W. bancrofti filarial antigen (WL-L2). The role of cytology cannot be underestimated in clinically unanticipated cases of bancroftian filariasis, especially with the amicrofilaremic state. Filariasis should always be considered in the differential diagnosis during cytological evaluation of any swelling, especially in endemic areas. PMID:26634138

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

    PubMed

    Meychik, N R; Yermakov, I P

    2001-02-01

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

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

    NASA Astrophysics Data System (ADS)

    Jaeger, F.; Schaumann, G. E.

    2009-04-01

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

  17. Swelling of phospholipid membranes by divalent metal ions depends on the location of the ions in the bilayers.

    PubMed

    Alsop, Richard J; Maria Schober, Rafaëla; Rheinstädter, Maikel C

    2016-08-10

    The Hofmeister series illustrates how salts produce a wide range of effects in biological systems, which are not exclusively explained by ion charge. In lipid membranes, charged ions have been shown to bind to lipids and either hydrate or dehydrate lipid head groups, and also to swell the water layer in multi-lamellar systems. Typically, Hofmeister phenomena are explained by the interaction of the ions with water, as well as with biological interfaces, such as proteins or membranes. We studied the effect of the divalent cations Mg(2+), Ca(2+), Fe(2+), and Zn(2+) on oriented, stacked, phospholipid bilayers made of dimyristoylphosphatidylcholine (DMPC). Using high-resolution X-ray diffraction, we observed that the cations lead to a swelling of the water layer between the bilayers, without causing significant changes to the bilayer structure. The cations swelled the bilayers in different amounts, in the order Fe(2+) > Mg(2+) > Ca(2+) > Zn(2+). By decomposing the total bilayer electron density into different molecular groups, Zn(2+) and Ca(2+) were found to interact with the glycerol groups of the lipid molecules and cause minor swelling of the bilayers. Mg(2+) and Fe(2+) were found to position near the phosphate groups and cause a strong increase in the number of hydration water molecules. Our results present a molecular mechanism-of-action for the Hofmeister series in phospholipid membranes. PMID:27453289

  18. 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

  19. Molecular accessibility in solvent swelled coals. Final report

    SciTech Connect

    Kispert, L.D.

    1994-04-01

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

  20. Obvious optic disc swelling in a patient with cryopyrin-associated periodic syndrome

    PubMed Central

    Kawai, Mariko; Yoshikawa, Tadanobu; Nishikomori, Ryuta; Heike, Toshio; Takahashi, Kanji

    2013-01-01

    Cryopyrin-associated periodic syndrome (CAPS) is a group of rare hereditary autoinflammatory diseases caused by mutations of the NLRP3 gene, and leads to excessive production of the proinflammatory cytokine, interleukin-lβ. A 35-year-old male presented with recurrent symptoms of urticarial-like rash, periodic fever, arthralgia, headache, and eye redness. His best-corrected visual acuity was 1.0 OD and 0.9 OS. Slit-lamp examination showed conjunctival and episcleral injection in both eyes. Ophthalmoscopy revealed obvious bilateral optic disc swelling and retinal vascular sheathing around the optic discs. Spectral domain optical coherence tomography also showed obvious optic disc swelling. Steroid and nonsteroidal anti-inflammatory drugs did not improve these symptoms. Genetic testing detected a heterozygous mutation of c.907G>A. Thus, the patient was genetically confirmed with CAPS. Visual acuity did not decrease for 3 years, although the optic discs became white in color. CAPS should therefore be distinguished from other disorders when examining optic disc swelling and/or uveitis patients with urticarial-like rash and periodic fever. PMID:23966762

  1. 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%.

  2. A transverse isotropic model for microporous solids: Application to coal matrix adsorption and swelling

    NASA Astrophysics Data System (ADS)

    Espinoza, D. N.; Vandamme, M.; Dangla, P.; Pereira, J.-M.; Vidal-Gilbert, S.

    2013-12-01

    Understanding the adsorption-induced swelling in coal is critical for predictable and enhanced coal bed methane production. The coal matrix is a natural anisotropic disordered microporous solid. We develop an elastic transverse isotropic poromechanical model for microporous solids which couples adsorption and strain through adsorption stress functions and expresses the adsorption isotherm as a multivariate function depending on fluid pressure and solid strains. Experimental data from the literature help invert the anisotropic adsorptive-mechanical properties of Brzeszcze coal samples exposed to CO2. The main findings include the following: (1) adsorption-induced swelling can be modeled by including fluid-specific and pressure-dependent adsorption stress functions into equilibrium equations, (2) modeling results suggest that swelling anisotropy is mostly caused by anisotropy of the solid mechanical properties, and (3) the total amount of adsorbed gas measured by immersing coal in the adsorbate overestimates adsorption amount compared to in situ conditions up to ˜20%. The developed fully coupled model can be upscaled to determine the coal seam permeability through permeability-stress relationships.

  3. Re-Evaluation of Sarcolemma Injury and Muscle Swelling in Human Skeletal Muscles after Eccentric Exercise

    PubMed Central

    Yu, Ji-Guo; Liu, Jing-Xia; Carlsson, Lena; Thornell, Lars-Eric; Stål, Per S.

    2013-01-01

    The results regarding the effects of unaccustomed eccentric exercise on muscle tissue are often conflicting and the aetiology of delayed onset muscle soreness (DOMS) induced by eccentric exercise is still unclear. This study aimed to re-evaluate the paradigm of muscular alterations with regard to muscle sarcolemma integrity and fibre swelling in human muscles after voluntary eccentric exercise leading to DOMS. Ten young males performed eccentric exercise by downstairs running. Biopsies from the soleus muscle were obtained from 6 non-exercising controls, 4 exercised subjects within 1 hour and 6 exercised subjects at 2–3 days and 7–8 days after the exercise. Muscle fibre sarcolemma integrity, infiltration of inflammatory cells and changes in fibre size and fibre phenotype composition as well as capillary supply were examined with specific antibodies using enzyme histochemistry and immunohistochemistry. Although all exercised subjects experienced DOMS which peaked between 1.5 to 2.5 days post exercise, no significant sarcolemma injury or inflammation was detected in any post exercise group. The results do not support the prevailing hypothesis that eccentric exercise causes an initial sarcolemma injury which leads to subsequent inflammation after eccentric exercise. The fibre size was 24% larger at 7–8 days than at 2–3 days post exercise (p<0.05). In contrast, the value of capillary number per fibre area tended to decrease from 2–3 days to 7–8 days post exercise (lower in 5 of the 6 subjects at 7–8 days than at 2–3 days; p<0.05). Thus, the increased fibre size at 7–8 days post exercise was interpreted to reflect fibre swelling. Because the fibre swelling did not appear at the time that DOMS peaked (between 1.5 to 2.5 days post exercise), we concluded that fibre swelling in the soleus muscle is not directly associated with the symptom of DOMS. PMID:23614012

  4. 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.

  5. 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.

  6. Geoid height versus topography for oceanic plateaus and swells

    NASA Technical Reports Server (NTRS)

    Sandwell, David T.; Mackenzie, Kevin R.

    1989-01-01

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

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

    SciTech Connect

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

    1981-01-01

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

  8. Non-breaking swell dissipation from synthethic aperture radar

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    SciTech Connect

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

    2006-11-27

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

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

    PubMed

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

    2012-10-15

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

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

    PubMed

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

    2012-02-01

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

  12. Shrinkage and Swelling of Coal Induced by Desorption and Sorption of Fluids: Theoretical Model and Interpretation of a Field Project

    SciTech Connect

    Siriwardane, H.J.; Gondle, R.K.; Smith, D.H.

    2009-01-01

    Geologic sequestration in deep unmineable coal seams and enhanced coalbed methane production is a promising choice, economically and environmentally, to reduce anthropogenic gases such as carbon dioxide in the atmosphere. Unmineable coal seams are typically known to adsorb large amounts of carbon dioxide in comparison to the sizeable amounts of sorbed methane, which raises the potential for large scale sequestration projects. During the process of sequestration, carbon dioxide is injected into the coalbed and desorbed methane is produced. The coal matrix is believed to shrink when a gas is desorbed and swell when a gas is sorbed, sometimes causing profound changes in the cleat porosity and permeability of the coal seam. These changes may have significant impact on the reservoir performance. Therefore, it is necessary to understand the combined influence of swelling and shrinkage, and geomechanical properties including elastic modulus, cleat porosity, and permeability of the reservoir. The present paper deals with the influence of swelling and shrinkage on the reservoir performance, and the geomechanical response of the reservoir system during the process of geologic sequestration of carbon dioxide and enhanced coalbed methane production in an actual field project located in northern New Mexico. A three-dimensional swelling and shrinkage model was developed and implemented into an existing reservoir model to understand the influence of geomechanical parameters, as well as swelling and shrinkage properties, on the reservoir performance. Numerical results obtained from the modified simulator were compared to available measured values from that site and previous studies. Results show that swelling and shrinkage, and the combination of geomechanical and operational parameters, have a significant influence on the performance of the reservoir system.

  13. [Cat Scratch Disease as a differential diagnosis in a patient with swelling in the groin].

    PubMed

    Makki, Ahmad; Murra, May; Sommer, Thorbjørn

    2014-08-11

    at Scratch Disease is caused by the bacteria Bartonella henselae and presents in patients exposed to a scratch/bite from cats. We present a case with a 12-year-old boy with an enlarged inguinal lymph node, initially suspected to be a femoral hernia by ultrasonography. Histologic examination of an inguinal lymph node showed necrosis and B. henselae infection. It is important with a thorough anamnesis including any history of animal bites/scratch and it should be kept in mind as a differential diagnosis in patients with swelling in the groin, despite the rare diagnosis of this disease.

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

    PubMed

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

    2015-03-28

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

  15. 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.

  16. Linear Viscoelasticity and Swelling of Polyelectrolyte Complex Coacervates

    NASA Astrophysics Data System (ADS)

    Hamad, Fawzi; Colby, Ralph

    2012-02-01

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

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

    PubMed

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

    2015-05-01

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

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

    PubMed

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

    2015-05-01

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

  19. 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...

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

    PubMed

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

    2016-07-01

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

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

    PubMed

    Loescher, A; Edmondson, H D

    1988-04-01

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

  2. 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)

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

    PubMed

    Strijbos, Ruben M; Zwaard, Ton M

    2015-01-01

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

  4. Anomalous swelling behavior of FM 5055 carbon phenolic composite

    NASA Technical Reports Server (NTRS)

    Stokes, E. H.

    1992-01-01

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

  5. 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.

  6. Case of a non-pulsatile groin swelling.

    PubMed

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

    2002-12-01

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

  7. In situ microscopy reveals reversible cell wall swelling in kelp sieve tubes: one mechanism for turgor generation and flow control?

    PubMed

    Knoblauch, Jan; Tepler Drobnitch, Sarah; Peters, Winfried S; Knoblauch, Michael

    2016-08-01

    Kelps, brown algae (Phaeophyceae) of the order Laminariales, possess sieve tubes for the symplasmic long-distance transport of photoassimilates that are evolutionarily unrelated but structurally similar to the tubes in the phloem of vascular plants. We visualized sieve tube structure and wound responses in fully functional, intact Bull Kelp (Nereocystis luetkeana [K. Mertens] Postels & Ruprecht 1840). In injured tubes, apparent slime plugs formed but were unlikely to cause sieve tube occlusion as they assembled at the downstream side of sieve plates. Cell walls expanded massively in the radial direction, reducing the volume of the wounded sieve elements by up to 90%. Ultrastructural examination showed that a layer of the immediate cell wall characterized by circumferential cellulose fibrils was responsible for swelling and suggested that alginates, abundant gelatinous polymers of the cell wall matrix, were involved. Wall swelling was rapid, reversible and depended on intracellular pressure, as demonstrated by pressure-injection of silicon oil. Our results revive the concept of turgor generation and buffering by swelling cell walls, which had fallen into oblivion over the last century. Because sieve tube transport is pressure-driven and controlled physically by tube diameter, a regulatory role of wall swelling in photoassimilate distribution is implied in kelps.

  8. In situ microscopy reveals reversible cell wall swelling in kelp sieve tubes: one mechanism for turgor generation and flow control?

    PubMed

    Knoblauch, Jan; Tepler Drobnitch, Sarah; Peters, Winfried S; Knoblauch, Michael

    2016-08-01

    Kelps, brown algae (Phaeophyceae) of the order Laminariales, possess sieve tubes for the symplasmic long-distance transport of photoassimilates that are evolutionarily unrelated but structurally similar to the tubes in the phloem of vascular plants. We visualized sieve tube structure and wound responses in fully functional, intact Bull Kelp (Nereocystis luetkeana [K. Mertens] Postels & Ruprecht 1840). In injured tubes, apparent slime plugs formed but were unlikely to cause sieve tube occlusion as they assembled at the downstream side of sieve plates. Cell walls expanded massively in the radial direction, reducing the volume of the wounded sieve elements by up to 90%. Ultrastructural examination showed that a layer of the immediate cell wall characterized by circumferential cellulose fibrils was responsible for swelling and suggested that alginates, abundant gelatinous polymers of the cell wall matrix, were involved. Wall swelling was rapid, reversible and depended on intracellular pressure, as demonstrated by pressure-injection of silicon oil. Our results revive the concept of turgor generation and buffering by swelling cell walls, which had fallen into oblivion over the last century. Because sieve tube transport is pressure-driven and controlled physically by tube diameter, a regulatory role of wall swelling in photoassimilate distribution is implied in kelps. PMID:26991892

  9. [Reconstructions after periorbital burn injuries].

    PubMed

    Klett, A; Rebane, R

    2013-01-01

    Nowadays burn patients who also have periocular symptoms are usually treated by reconstructive surgeons and the role of the ophthalmic surgeon has decreased.Although periocular complications occur in a minority of burned patients, they pose a greater challenge in surgical and non-surgical treatment. Chemical, electrical and thermal burns can lead to disfiguring scar formations and delayed treatment can lead to devastating ocular complications. Achieving a successful reconstruction requires a comprehensive approach, entailing many advanced techniques with an emphasis on preserving function and balancing intricate aesthetic requirements. The theory is illustrated in this article with clinical examples. PMID:23345146

  10. 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.

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

    NASA Astrophysics Data System (ADS)

    Yu, Ho

    1980-11-01

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

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

    PubMed

    Segad, M; Cabane, B; Jönsson, Bo

    2015-10-21

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

  13. Osteoma Presenting as a Painless Solitary Mastoid Swelling

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2010-04-01

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

  15. 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

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

    NASA Astrophysics Data System (ADS)

    Choi, Young Joon; Hulsen, Martien A.

    2011-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  18. 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.

  19. Ion implantation induced swelling in 6H-SiC

    SciTech Connect

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

    1997-06-01

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

  20. 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.

  1. 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

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

    PubMed

    Zou, Maggie; Reid, Diane; Ravichandran, Duraisamy

    2015-01-01

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

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

    PubMed

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

    2016-11-01

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

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

    SciTech Connect

    Doetschman, D.C.

    1994-10-26

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

  5. Xanthogranulomatous Osteomyelitis Presenting as Swelling in Right Tibia

    PubMed Central

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

    2011-01-01

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

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

    PubMed

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

    1982-09-01

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

  7. Molecular accessibility in solvent swelled coals. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1993-02-01

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

  8. Theoretical and numerical studies of die swell flow

    NASA Astrophysics Data System (ADS)

    Al-Muslimawi, Alaa H.

    2016-08-01

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

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

    PubMed

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

    2015-06-01

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

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

    PubMed

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

    2016-06-01

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

  11. 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.

  12. Conceptual design of a device to measure hand swelling in a micro-gravity environment

    NASA Technical Reports Server (NTRS)

    Hysinger, Christopher L.

    1993-01-01

    In the design of pressurized suits for use by astronauts in space, proper fit is an important consideration. One particularly difficult aspect of the suit design is the design of the gloves. If the gloves of the suit do not fit properly, the grip strength of the astronaut can be decreased by as much as fifty percent. These gloves are designed using an iterative process and can cost over 1.5 million dollars. Glove design is further complicated by the way the body behaves in a micro-gravity environment. In a micro-gravity setting, fluid from the lower body tends to move into the upper body. Some of this fluid collects in the hands and causes the hands to swell. Therefore, a pair of gloves that fit well on earth may not fit well when they are used in space. The conceptual design process for a device which can measure the swelling that occurs in the hands in a micro-gravity environment is described. This process involves developing a specifications list and function structure for the device and generating solution variants for each of the sub functions. The solution variants are then filtered, with the variants that violate any of the specifications being discarded. After acceptable solution variants are obtained, they are combined to form design concepts. These design concepts are evaluated against a set of criteria and the design concepts are ranked in order of preference. Through this process, the two most plausible design concepts were an ultrasonic imaging technique and a laser mapping technique. Both of these methods create a three dimensional model of the hand, from which the amount of swelling can be determined. In order to determine which of the two solutions will actually work best, a further analysis will need to be performed.

  13. Effects of Temperature and Gas Composition on Reduction and Swelling of Magnetite Concentrates

    NASA Astrophysics Data System (ADS)

    Kapelyushin, Yury; Sasaki, Yasushi; Zhang, Jianqiang; Jeong, Sunkwang; Ostrovski, Oleg

    2016-08-01

    The gaseous reduction of magnetite ore concentrates was studied using CO-CO2 and CO-CO2-H2 gas mixtures at different temperatures and gas compositions. The reduction of magnetite ore by CO-CO2 gas mixture was examined at temperatures 973 K to 1173 K (700 °C to 900 °C) at CO/CO2 ratio 80/20, and at varied CO/CO2 ratio from 60/40 to 85/15 at 1023 K (750 °C). In the reduction of magnetite ore by CO-CO2-H2 gas mixture, temperature was 1173 K (800 °C) and hydrogen content changed from 5 to 25 vol pct at constant CO/CO2 ratio of 80/20. Reduction of magnetite ore did not go to completion in both CO-CO2 and CO-CO2-H2 gas mixtures. Addition of H2 to the CO-CO2 gas mixture accelerated the reduction in the first 10 to 30 minutes of reaction. However, the degree of reduction by gas containing 5 to 25 vol pct H2 after 60 to 120 minutes of reaction was in the range 60 to 65 pct, while the degree of reduction by CO-CO2 gas (80 vol pct CO) after 120 minutes of reaction was close to 70 pct. Significant swelling of magnetite ore pellets was observed in the reduction by CO-CO2 gas mixture. Addition of H2 to the CO-CO2 gas mixture decreased swelling. Swelling of magnetite ore during the reduction was attributed to the breakout of iron layer caused by the increase of the inner pressure in the voids at the wüstite/iron phase boundary.

  14. 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.

  15. 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.

  16. 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

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

    NASA Astrophysics Data System (ADS)

    Wang, Weili; Forget, Philippe; Guan, Changlong

    2016-04-01

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

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

    PubMed

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

    2003-10-01

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

  19. External jugular vein aneurysm: a rare cause of neck swelling. A report of three patients.

    PubMed

    Azghari, A; Belmir, H; Kharroubi, A; El Khaloufi, S; El Idrissi, R; Lekehal, B; Sefiani, Y; El Mesnaoui, A; Ammar, F; Bensaid, Y

    2011-12-01

    Venous aneurysms are a relatively rare pathology, far less common than arterial aneurysms. Unrelated to either age or gender, they can affect any vein, including cervical, thoracic, visceral, and lower limb veins. Aneurysmal dilatations in cervical veins are rare due to low pressure in the vena cava system; they can involve any vein but most frequently are observed on the internal and external jugular veins. This report of three patients highlights some of the specific diagnostic and therapeutic features of this pathology. PMID:21885226

  20. Isolated retroperitoneal hydatid cyst in a child: a rare cause of acute scrotal swelling?

    PubMed

    Khan, Rizwan Ahmad; Wahab, Shagufta; Chana, Rajendra Singh; Fareed, Rehan

    2010-08-01

    Hydatidosis affects almost every region of the body. Although adults are mostly affected, children also suffer from the disease especially in endemic areas. The usual affected location is the liver, lung, spleen, brain, and kidney. We report a hydatid cyst located in a retroperitoneal location presenting with a sudden scrotal extension in a 7-year-old child. The finding presented a diagnostic dilemma vis-à-vis obstructed inguinal hernia.

  1. Hydrocele of the Canal of Nuck (Female Hydrocele): A Rare Differential for Inguino-Labial Swelling.

    PubMed

    Sarkar, Santanu; Panja, Soumyajyoti; Kumar, Sandeep

    2016-02-01

    The inguinal canal is traversed by the spermatic cord in men and the round ligament of uterus in women. The round ligament is attached to the uterine cornu near the origin of fallopian tube at one end and to the ipsilateral labia majora at the other. The round ligament accompanies a pouch of parietal peritoneum in the inguinal canal, which is known as 'canal of nuck'. It is analogous to the processus vaginalis in males. Incomplete obliteration of the peritoneal pouch causes indirect inguinal hernia or hydrocele of the canal of nuck; a very rare condition in women. As these types of cases are rarely seen in surgical practice we present a case of such little-known developmental disorder in a three-year-old girl. She presented with irreducible, tender right inguino-labial swelling with tachycardia simulating incarcerated inguinal hernia, which necessitates emergency surgical exploration. On exploration it was found to be an encysted hydrocele of canal of nuck; so although rare, this entity should be considered in differential diagnosis in a female child presented with inguino-labial swelling.

  2. Swelling and Gas Evolution in Irradiated Organic Matrix COMPOSITES—A Review

    NASA Astrophysics Data System (ADS)

    Evans, D.

    2010-04-01

    When irradiated with high energy particles, all organic materials produce gas as a result of bond scission or nuclear displacement reactions that may occur and the rate of gas evolution can be related to the chemical structure of the material. The relationship between rate of gas evolution and temperature of irradiation is complex, but it is believed that providing the material is irradiated at a temperature below its Tg, there is little influence of temperature on the total gas evolved. A number of investigators have considered the possibility that radiolytic gases, if not lost by normal diffusion processes, will be trapped within the material and so causes the resin to `swell'. There is a particular concern that when materials are irradiated at low temperatures, gases may be released suddenly as the material is warmed, minimising the possibility of loss by diffusion and so leading to an increase in dimensions. This paper reviews the literature on gas evolution and any associated swelling that may occur and for epoxies, correlates gas evolution rates with chemical structure.

  3. Hydrocele of the Canal of Nuck (Female Hydrocele): A Rare Differential for Inguino-Labial Swelling

    PubMed Central

    Panja, Soumyajyoti; Kumar, Sandeep

    2016-01-01

    The inguinal canal is traversed by the spermatic cord in men and the round ligament of uterus in women. The round ligament is attached to the uterine cornu near the origin of fallopian tube at one end and to the ipsilateral labia majora at the other. The round ligament accompanies a pouch of parietal peritoneum in the inguinal canal, which is known as ‘canal of nuck’. It is analogous to the processus vaginalis in males. Incomplete obliteration of the peritoneal pouch causes indirect inguinal hernia or hydrocele of the canal of nuck; a very rare condition in women. As these types of cases are rarely seen in surgical practice we present a case of such little-known developmental disorder in a three-year-old girl. She presented with irreducible, tender right inguino-labial swelling with tachycardia simulating incarcerated inguinal hernia, which necessitates emergency surgical exploration. On exploration it was found to be an encysted hydrocele of canal of nuck; so although rare, this entity should be considered in differential diagnosis in a female child presented with inguino-labial swelling. PMID:27042529

  4. Distinctive neck swelling in a patient with a vein of Galen arteriovenous malformation.

    PubMed

    Agarwal, Arnav; Firdouse, Mohammed; De Almeida, Claudia Lace; Mondal, Tapas

    2015-06-01

    A vein of Galen arteriovenous malformation (VGAM) is a rare intracranial shunt lacking a capillary bed and resulting in subsequent aneurysmal enlargement. VGAM has been previously reported to present as cardiovascular abnormalities, including increased right-sided cardiac load and pressure, cardiac dilatation, pulmonary hypertension and retrograde flow into the aortic arch. We report the first case of VGAM presenting as a gross right-sided neck swelling in a 39-week-old immediately at birth. Transthoracic echocardiography detected dilatation of the superior vena cava and innominate vein, increased right ventricular and pulmonary arterial pressure, and retrograde flow into the aortic arch. Follow-up neck ultrasound revealed tortuous carotid artery and bilateral dilatation of neck veins. Transcranial ultrasound revealed abnormally dilated vessels posterior to the third ventricle, confirming VGAM. Our case demonstrates that while the differential diagnoses of neck swelling are extensive, such a presentation upon Doppler and echocardiographic investigation, may be suggestive of extracardiac causes such as VGAM. The management of such a condition remains critical due to risk of hemorrhage and extensive cerebral involvement.

  5. Anisotropic swelling and microcracking of neutron irradiated Ti3AlC2-Ti5Al2C3 materials

    DOE PAGES

    Ang, Caen K.; Silva, Chinthaka M.; Shih, Chunghao Phillip; Koyanagi, Takaaki; Katoh, Yutai; Zinkle, Steven J.

    2015-12-17

    Mn + 1AXn (MAX) phase materials based on Ti–Al–C have been irradiated at 400 °C (673 K) with fission neutrons to a fluence of 2 × 1025 n/m2 (E > 0.1 MeV), corresponding to ~ 2 displacements per atom (dpa). We report preliminary results of microcracking in the Al-containing MAX phase, which contained the phases Ti3AlC2 and Ti5Al2C3. Equibiaxial ring-on-ring tests of irradiated coupons showed that samples retained 10% of pre-irradiated strength. Volumetric swelling of up to 4% was observed. Phase analysis and microscopy suggest that anisotropic lattice parameter swelling caused microcracking. Lastly, variants of titanium aluminum carbide may bemore » unsuitable materials for irradiation at light water reactor-relevant temperatures.« less

  6. Drug-Loaded Nanoparticles from 'Ershiwuwei Shanhu' Pill Induced Cellular Swelling of SH-SY5Y Neuroblastoma Cells.

    PubMed

    Liu, Yali; Song, Xiaoping; Zheng, Siting; Luo, Yuandai; Wang, Leyu; Huang, Fukai; Qiu, Xiaozhong

    2016-03-01

    Drug-loaded nanoparticles from 'Ershiwuwei Shanhu' Pill (ESP) inducing cellular swelling of the SH-SY5Y neuroblastoma cells were investigated. Electron microscope was used to observe nanoparticles existing in the freeze-dried supernatant of 'Ershiwuwei Shanhu' Pill. Drug-free nanoparticles were obtained from the solution of drug-loaded nanoparticles via dialysis. The size and zeta potential of two kinds of nanoparticles were tested by granularmetric analysis and surface charge analysis. Results showed that nanoparticles could penetrate into cellular nucleus and caused cell swelling. CCK8 analysis implied that low concentration of drug-free nanoparticles from 'Ershiwuwei Shanhu' Pill can induce cell proliferation of the SH-SY5Y neuroblastoma cells, while drug-loaded nanoparticles can reduce cell viability through NF-κB pathway. Drug-loaded nanoparticles existed in 'Ershiwuwei Shanhu' pill might play a vital role during pharmacotherapy, which served as nanocarriers in delivering drugs into cells.

  7. The engineering significance of shrinkage and swelling soils in blast damage investigations

    SciTech Connect

    Vitton, S.J.; Harris, W.W.

    1996-12-01

    In the US each year it has been estimated that expansive soils cause approximately $9.0 billion in damage to buildings, roads, airports, and other facilities. This figure alone exceeds the damage estimate for earthquakes, floods, tornadoes, and hurricanes combined. Unfortunately, some cases of expansive soil damage (swelling) are blamed on rock blasting operations if the blasting operations are located within the immediate area. While simple tests, such as the Atterberg limits test, can characterize a soil as expansive, it does not necessarily answer the question whether the foundation soils are causing distresses to a structure. In particular, it appears that once a soil has been labeled as nonexpansive it is no longer considered as a problem soil, in which case blast vibrations become the prime suspect. It should be emphasized, however, that even non-plastic soils, those soils with low to nonexistent plastic indexes, can exhibit significant shrinkage characteristics that can result in significant damage to structures. While expansive soil is a function of the mineralogy of the soil particles, i.e., swelling clay minerals, shrinkage is caused by the loss of moisture from soil as capillary pressures exceed the cohesion or tensile strength and is therefore a function of the soils particle size and its pore size distribution. This is a significant problem for all fine grained soils regardless of the soil`s mineralogy. It`s particularly important for regions of the US that typically have a positive water balance but experience significant drought periods when soil moisture is lost.

  8. 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

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

    PubMed

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

    2015-01-01

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

  10. On sorption and swelling of CO2 in clays

    DOE PAGES

    Busch, A.; Bertier, P.; Gensterblum, Y.; Rother, G.; Spiers, C. J.; Zhang, M.; Wentinck, H. M.

    2016-03-23

    One well-studied technology is the geological storage of carbon dioxide (CO2), and a number of demonstration projects around the world have proven its feasibility and challenges. Storage conformance and seal integrity are among the most important aspects, as they determine risk of leakage as well as limits for storage capacity and injectivity. By providing evidence for safe storage is critical for improving public acceptance. Most caprocks are composed of clays as dominant mineral type which can typically be illite, kaolinite, chlorite or smectite. A number of recent studies addressed the interaction between CO2 and these different clays and it wasmore » shown that clay minerals adsorb considerable quantities of CO2. For smectite this uptake can lead to volumetric expansion followed by the generation of swelling pressures. On the one hand CO2 adsorption traps CO2, on the other hand swelling pressures can potentially change local stress regimes and in unfavourable situations shear-type failure is assumed to occur. Moreover, for storage in a reservoir having high clay contents the CO2 uptake can add to storage capacity which is widely underestimated so far. Smectite-rich seals in direct contact with a dry CO2 plume at the interface to the reservoir might dehydrate leading to dehydration cracks. Such dehydration cracks can provide pathways for CO2 ingress and further accelerate dewatering and penetration of the seal by supercritical CO2. At the same time, swelling may also lead to the closure of fractures or the reduction of fracture apertures, thereby improving seal integrity. Finally, the goal of this communication is to theoretically evaluate and discuss these scenarios in greater detail in terms of phenomenological mechanisms, but also in terms of potential risks or benefits for carbon storage.« less

  11. Swelling of the vesicle is prerequisite for PTH secretion.

    PubMed

    Lim, S K; Kwon, Y H; Song, Y D; Lee, H C; Ryu, K J; Huh, K B; Park, C S

    1996-02-01

    Unlike most secretory cells, high extra cellular calcium inhibits rather than stimulates hormonal secretion in several cells such as parathyroid cells, Juxtaglomerular cells and osteoclast. To gain further insight into the common but unique stimulus-secretion coupling mechanism in these cells, bovine parathyroid slices were incubated in various conditions of Krebs-Ringer (KR) solution containing essential amino acids. Parathyroid cells showed the inverse dependency of secretion on extra cellular calcium concentration as we expected. Ammonium acetate overcame the inhibitory effect of 2.5 mM of calcium and the maximum effect was as much as the five times of the basal value, while there was a little additive effect under 0 mM CaCl2. PTH secretion was biphasic according to the change of extra cellular osmolarity and the lowest response was observed at 300 mOsm/l. In Na-rich KR solution, high concentration of nigericin (> 10(-4)M) completely overcame the inhibitory effect of 2.5 mM CaCl2 and the maximum stimulatory effect was 8 times greater whereas it was only 2 times greater without CaCl2. In K-rich KR solution that abolished the K-gradient between the extra cellular solution and the cytoplasm, the rate of PTH secretion increased, and furthermore the addition of nigericin increased the rate of secretion significantly. The results above suggested that the osmotic swelling of the secretory vesicle in parathyroid cells might promote exocytosis as in Juxtaglomerular cells. We propose that the swelling of the vesicle is also prerequisite for secretion in several cells inhibited paradoxically by Ca++, whatever the signal transduction pathway for swelling of the secretory granules induced by the lowering of Ca++ in cytoplasm are.

  12. 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.

  13. Determination of yeast mitochondrial KHE activity, osmotic swelling and mitophagy.

    PubMed

    Nowikovsky, Karin; Devenish, Rodney J; Froschauer, Elisabeth; Schweyen, Rudolf J

    2009-01-01

    The mitochondrial K(+)/H(+) exchanger (KHE) is a key regulator of mitochondrial K(+), the most abundant cellular cation, and thus for volume control of the organelle. Downregulation of the mitochondrial KHE results in osmotic swelling and autophagic degradation of the organelle. This chapter describes methods to shut-off expression of Mdm38p, an essential factor of the mitochondrial KHE, and to observe the cellular consequences thereof, in particular changes in KHE activity and morphogenetic changes of mitochondria by applying new techniques developed in our laboratories. PMID:19426875

  14. Cornea, and the swelling of polyelectrolyte gels of biological interest

    NASA Astrophysics Data System (ADS)

    Elliott, Gerald F.; Hodson, Stuart A.

    1998-10-01

    Biological polyelectrolyte gels consist of insoluble aggregates of molecules which collectively form structural fibrils and these fibrils, or their chemically bound side chains, have a net electrical charge. These gels may be visualized as negatively charged fibrils immersed in aqueous solutions which include free diffusible ions (mainly sodium, potassium and chloride). All living cells and most of the extracellular spaces of the body are polyelectrolyte gels and they strive to swell by the absorption of additional fluid because of the Donnan potentials generated by their fixed charge. We review Donnan swelling using the cornea of the eye as prime material. Donnan swelling requires knowledge of only one parameter such as: (a) the electrical potential within the gel or (b) the distribution of any mobile ion inside and outside the gel or (c) measurement of the gel pressure or (d) the fixed charge density on the fibrils, in order to calculate all the other relevant factors. We describe the conditions (which usually exist in biological tissue) when the microscopic distribution of the fixed charge density within the gel is not important to the Donnan phenomena. Fixed charge density is generated by two sources: permanent negative charges in the structural fibrils and transient mobile ion binding to the fibrils. Ion binding to large molecules is reviewed. In the case of the cornea, transient mobile ion binding is the predominant factor in generating fixed charge density under physiological conditions. An irreversible thermodynamic treatment of gel swelling shows the intrinsic instability of polyelectrolyte gels and suggests new ways of approaching a microscopic model for osmosis. In order to stabilize the two forces (osmotic potential and chemical potential) which generate the polyelectrolyte gel instability we review the types of third forces which must be present in order to stabilize biological gels. These third forces include van der Waal's force, metabolically driven

  15. A young boy with a maxillary swelling and closed rhinolalia.

    PubMed

    Thomas, Shaji; Nair, Preeti; Kumar, Anil; Hegde, Karthik; Singh, Vikram

    2011-01-01

    Non-Hodgkin's lymphoma belongs to a group of lymphoid neoplasia that is diverse in the manner of presentation, response to therapy and progress. The most common region for extranodal lymphoma is the gastrointestinal tract while for oral cavity buccal vestibule, posterior hard palate or gingiva is the common site. The maxilla is affected more commonly than the mandible. The oral picture being the sole manifestation highlights the importance of bearing this entity in the differential diagnosis of swelling in the jaws. PMID:22715226

  16. Dynamic measurement of starch granule swelling during microwave heating.

    PubMed

    Casasnovas, Johnny; Anantheswaran, Ramaswamy C

    2016-10-20

    The size of starch granules in dilute aqueous suspension was measured in-line during gelatinization in a microwave-heated, well-mixed system. The results were compared with those of a previous study conducted with conventional heating. For the starches used (common corn, waxy maize, and cross-linked waxy maize), no significant difference was found between microwave and conventional heating in terms of maximum diameter, temperature of maximum rate of diameter increase, or diameter vs. temperature behavior. These results suggest that there are no differences in the swelling behavior of common and modified maize starches between microwave and conventional heating. PMID:27474654

  17. 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.

  18. Molecular accessibility in solvent swelled coal. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1992-05-29

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

  19. Molecular accessibility in solvent swelled coal. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1992-08-01

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

  20. Equilibrium swelling of elastomeric materials in solvent environments

    SciTech Connect

    Green, P.F.

    1990-03-01

    The equilibrium swelling of silicones, fluorosilicones, VITON and ethylene-propylene-diene (EPDM) elastomers in an environment of the jet fuel JP4 was investigated. The volume of silicone and DPDM elastomers increased by approximately 100% when they were placed in a saturated environment of JP4. Conversely, the volume of the fluorosilicone elastomer increased by approximately 15% and that of VITON less than 1%. In acetone, a commonly used solvent, the equilibrium swelling of VITON and the fluorosilicone elastomer was excessive, on the order of 100%, wheras the silicone and EPDM elastomers exhibited small changes in dimensions. Reasons for these observations are discussed in detail. We also present a simple scheme by which one may, qualitatively, determine the dimensional stability of these elastomers in different solvents if the cohesive energy density of the solvent, which is readily available in a number of handbooks, is known. We also evaluated the vulnerability of some commonly used engineering thermoplastics to JP4. The results are tabulated. 13 refs., 6 figs., 3 tab.

  1. 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.

  2. Swelling Mechanisms of UO2 Lattices with Defect Ingrowths.

    PubMed

    Günay, Seçkin D

    2015-01-01

    The swelling that occurs in uranium dioxide as a result of radiation-induced defect ingrowth is not fully understood. Experimental and theoretical groups have attempted to explain this phenomenon with various complex theories. In this study, experimental lattice expansion and lattice super saturation were accurately reproduced using a molecular dynamics simulation method. Based on their resemblance to experimental data, the simulation results presented here show that fission induces only oxygen Frenkel pairs while alpha particle irradiation results in both oxygen and uranium Frenkel pair defects. Moreover, in this work, defects are divided into two sub-groups, obstruction type defects and distortion type defects. It is shown that obstruction type Frenkel pairs are responsible for both fission- and alpha-particle-induced lattice swelling. Relative lattice expansion was found to vary linearly with the number of obstruction type uranium Frenkel defects. Additionally, at high concentrations, some of the obstruction type uranium Frenkel pairs formed diatomic and triatomic structures with oxygen ions in their octahedral cages, increasing the slope of the linear dependence. PMID:26244777

  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. Hereditary Angioedema Attacks: Local Swelling at Multiple Sites.

    PubMed

    Hofman, Zonne L M; Relan, Anurag; Hack, C Erik

    2016-02-01

    Hereditary angioedema (HAE) patients experience recurrent local swelling in various parts of the body including painful swelling of the intestine and life-threatening laryngeal oedema. Most HAE literature is about attacks located in one anatomical site, though it is mentioned that HAE attacks may also involve multiple anatomical sites simultaneously. A detailed description of such multi-location attacks is currently lacking. This study investigated the occurrence, severity and clinical course of HAE attacks with multiple anatomical locations. HAE patients included in a clinical database of recombinant human C1-inhibitor (rhC1INH) studies were evaluated. Visual analog scale scores filled out by the patients for various symptoms at various locations and investigator symptoms scores during the attack were analysed. Data of 219 eligible attacks in 119 patients was analysed. Thirty-three patients (28%) had symptoms at multiple locations in anatomically unrelated regions at the same time during their first attack. Up to five simultaneously affected locations were reported. The observation that severe HAE attacks often affect multiple sites in the body suggests that HAE symptoms result from a systemic rather than from a local process as is currently believed. PMID:25527240

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Shrinkage/swelling of compacted clayey loose and dense soils

    NASA Astrophysics Data System (ADS)

    Nowamooz, Hossein; Masrouri, Farimah

    2009-11-01

    This Note presents an experimental study performed on expansive compacted loose and dense samples using osmotic oedometers. Several successive wetting and drying cycles were applied in a suction range between 0 and 8 MPa under different values of constant net vertical stress (15, 30, and 60 kPa). During the suction cycles, the dense samples showed cumulative swelling strains, while the loose samples showed volumetric shrinkage accumulation. At the end of the suction cycles, the volumetric strains converged to an equilibrium stage that indicated elastic behavior of the swelling soil for any further hydraulic variations. At this stage, the compression curves for the studied soil at the different imposed suctions (0, 2, and 8 MPa) converged towards the saturated state curve for the high applied vertical stresses. We defined this pressure as the saturation stress(P). The compression curves provided sufficient data to examine the soil mechanical behavior at the equilibrium stage. To cite this article: H. Nowamooz, F. Masrouri, C. R. Mecanique 337 (2009).

  11. Swelling and osmotic flow in a potential host rock

    NASA Astrophysics Data System (ADS)

    Horseman, S. T.; Harrington, J. F.; Noy, D. J.

    Measurements of osmotic and hydraulic permeability are reported for a series of tests conducted on Opalinus Clay samples from the Mt. Terri underground research laboratory in the Jura Mountains of NE Switzerland. Osmotic flow was observed across discs of this clayshale separating 0.245 M NaCl solution from distilled water. Pressure transients monitored during constant flow rate testing were analysed to give permeability and specific storage values. The mean permeability normal to bedding of the two Opalinus Clay specimens was 7.9 × 10 -21 m 2. The mean specific storage based on all reliable determinations was 4.1 × 10 -4 m -1. Values calculated from the steady-state pressure gradients established during constant flow rate testing were very close to those obtained by mathematical analysis of pressure transients. The calculation of the transients was carried out using a new model of flow and solute transport which included terms for the osmotic coupling. The form of the pressure transients and the magnitude of the strain seen during the tests lead to a revision to the definition of solid phase compressibility to incorporate a term dependent upon the osmotic coupling coefficient. Steady-state osmotic flow rates were in the range 0.1-0.6 μL h -1 when the specimens were placed between a sodium chloride solution with a theoretical osmotic pressure of 1.19 MPa and distilled water. Transient flow rates were substantially larger. Membrane efficiencies were found to be relatively low, ranging from 1% to 6% (mean around 4%). The mean osmotic permeability normal to bedding was 3.5 × 10 -22 m 2. Specific storage and pore compressibility values were substantially larger than anticipated, suggesting that the volumetric strain of the clayshale under the conditions of laboratory testing must be largely determined by quasi-elastic deformation processes such as swelling and crack dilation. To test this hypothesis, a 3-D swelling test was performed on a cubic specimen of the same

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

    PubMed Central

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

    2015-01-01

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

  13. Melkerrson-Rosenthal Syndrome, a rare case report of chronic eyelid swelling

    PubMed Central

    2013-01-01

    Abstract Melkerrson-Rosenthal syndrome is a rare disorder of unknown etiology. The classical triad of recurrent facial paralysis, swelling of the face, lips and deep furrowed tongue (Lingua Plicata) is seen in very few cases, majority of the patients often present with one or two symptoms only, which often leads to misdiagnosis and mismanagement. Clinically these symptoms vary from days to years, which further delay the definitive diagnosis and symptoms may eventually become permanent. The cause of this entity is not very well understood, but thought to be attributable to multiple entities including genetic and Infectitious. As this entity has been associated with numerous other clinical entities, diagnosis often remains an exclusion process. Methods: A middle age male with a chronic history of heavy eyelids with skin indurations predominately around left eye was presented to ophthalmology clinic. Physical examination revealed a deep furrowed tongue. The skin biopsy from left eyelid revealed a non-specific granulomatous lesion. The clinical correlation of facial swelling and deep plicated tongue prompted the differential of MRS Results: Histologically a non-specific granulomatous lesion was seen in dermis. As a rule, other causes of granulomatous diseases were ruled out especially Crohn’s disease and sarcoidosis. Polarization failed to reveal any foreign body. Conclusions: The finding of granulomatous lesion and clinical picture led to the definite diagnosis of Melkerrson-Rosenthal syndrome. Association with rosacea was other findings. Clinically his sign and symptoms are under control and no occurrence of symptoms has been noted so far. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1647494495993706 PMID:24225172

  14. Swell dissipation from 10 years of Envisat advanced synthetic aperture radar in wave mode

    NASA Astrophysics Data System (ADS)

    Stopa, Justin E.; Ardhuin, Fabrice; Husson, Romain; Jiang, Haoyu; Chapron, Bertrand; Collard, Fabrice

    2016-04-01

    Swells are found in all oceans and strongly influence the wave climate and air-sea processes. The poorly known swell dissipation is the largest source of error in wave forecasts and hindcasts. We use synthetic aperture radar data to identify swell sources and trajectories, allowing a statistically significant estimation of swell dissipation. We mined the entire Envisat mission 2003-2012 to find suitable storms with swells (13 < T < 18 s) that are observed several times along their propagation. This database of swell events provides a comprehensive view of swell extending previous efforts. The analysis reveals that swell dissipation weakly correlates with the wave steepness, wind speed, orbital wave velocity, and the relative direction of wind and waves. Although several negative dissipation rates are found, there are uncertainties in the synthetic aperture radar-derived swell heights and dissipation rates. An acceptable range of the swell dissipation rate is -0.1 to 6 × 10-7 m-1 with a median of 1 × 10-7 m-1.

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

    NASA Astrophysics Data System (ADS)

    Wangler, Timothy

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

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

    PubMed Central

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

    2005-01-01

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

  17. Longitudinal design for sonographic measurement of median nerve swelling with controlled exposure to physical work using an animal model.

    PubMed

    Roll, Shawn C; Evans, Kevin D; Volz, Kevin R; Sommerich, Carolyn M

    2013-12-01

    In the study described here, we examined the feasibility of a longitudinal design to measure sonographically swelling of the median nerve caused by controlled exposure to a work task and to evaluate the relationship of changes in morphology to diagnostic standards. Fifteen macaques, Macaca fascicularis, pinched a lever in various wrist positions at a self-regulated pace (8 h/d, 5 d/wk, 18-20 wk). Nerve conduction velocity (NCV) and cross-sectional area (CSA) were measured every 2 wk from baseline through working and a 6-wk recovery. Trending across all subjects revealed that NCV slowed and CSA at the carpal tunnel increased in the working arm, whereas no changes were observed in CSA either at the forearm or for any measure in the non-working arm. There was a small negative correlation between NCV and CSA in the working arm. This study provides validation that swelling can be observed using a longitudinal design. Longitudinal human studies are needed to describe the trajectory of nerve swelling for early identification of median nerve pathology.

  18. Synthesis and characterization of fast-swelling porous superabsorbent hydrogel based on starch as a hemostatic agent.

    PubMed

    Mirzakhanian, Zeinab; Faghihi, Khalil; Barati, Abolfazl; Momeni, Hamid Reza

    2015-01-01

    The body can't control massive bleeding without treatment. Different hemostatic agents have been prepared recently, but most of them are ineffective in severe bleeding and expensive or cause safety concerns. In this study, in order to achieve fast control of bleeding, we synthesized and characterized fast-swelling porous superabsorbent hydrogel (FSPSH) and investigated its use as a hemostatic agent. The FSPSH was prepared by grafting acrylic acid and acrylamide onto starch through free-radical polymerization in aqueous solution. The FSPSH was characterized by Fourier transform infrared, X-ray diffraction, field emission scanning electron microscope, and thermogravimetric analysis. Then, temporal swelling behavior and coagulation time experiments were used to predict the in vivo behavior of the FSPSH. The hemocompatibility of synthesized FSPSH was evaluated by hemolysis test and blood cells function. In vivo study using femoral artery injury in rat demonstrated the FSPSH's ability to aid in rapid hemostasis. Furthermore, monitoring the rat on first and seventh day after femoral artery injury also showed no harmful effect. This study indicates that FSPSH adsorbs fluid and swells, thus forms a physical barrier to blood loss. FSPSH, moreover, as hemostat is simple to use, lightweight, stable, and harmless. PMID:26481485

  19. Swelling of ion-irradiated 3C-SiC characterized by synchrotron radiation based XRD and TEM

    NASA Astrophysics Data System (ADS)

    Lin, Yan-Ru; Ho, Chun-Yu; Chuang, Wei-Tsung; Ku, Ching-Shun; Kai, Ji-Jung

    2014-12-01

    An experimental technique was established to characterize irradiation-induced volume swelling through a combined utilization of synchrotron radiation-based X-ray diffraction (XRD) and transmission electron microscopy (TEM). 3C-SiC specimens were irradiated by Si2+ ions (5 MeV) with fluences up to 5 × 1017 ion/cm2 at 1000 °C. In order to avoid the accumulation of implanted Si ions in the SiC layer, specific thicknesses of the epitaxy layer and implanted ion energy were chosen. Unresolvable black spot defects were studied by TEM, and the average size and density were calculated. XRD radial scan results of surface (0 0 2), (1 1 1), (0 2 2), (1 1 3), and (2 0 0) including peak shift and asymmetry peak broadening were observed. Different interplanar spacing information of single crystal SiC can be obtained from this XRD measurement method, making it possible to investigate the lattice expansion and volume swelling more precisely. While TEM provided a direct visualization of the microstructures and the interplanar spacing was measured from HRTEM images. It is suggested that irradiation induced point defects and compressive stress from the Si substrate were the cause of anisotropic (a = b < c) volume swelling of irradiated 3C-SiC in this study.

  20. Coupling pH-responsive polymer brushes to electricity: switching thickness and creating waves of swelling or collapse.

    PubMed

    Dunderdale, Gary J; Fairclough, J Patrick A

    2013-03-19

    Electrolysis of water is proposed as a method to couple the pH-responsive behavior of polymer brushes to an electrical stimulus. It is shown that an electrode in close proximity to a pH-responsive polymer brush can change the local solution pH, inducing either swelling or collapse of the polymer brush. By alternating the bias of the voltage applied to the electrode, either acidic or alkaline conditions can be generated, and reproducible cycles of polymer brush swelling and collapse can be achieved. It was found that the length of time which the electrical stimulus is applied to the electrodes can be as short as 10 s and that, once "switched", polymer brushes remain in the switched state for many minutes after the electrical stimulus is turned off. In other experiments, two electrodes were positioned 10 cm apart with a pH-responsive brush in between. Under these conditions waves of either acidic or alkaline solution pH could be generated which caused a coincident wave of polymer brush swelling or collapse. These waves originate from one electrode and travel across the brush surface toward the opposite electrode with a velocity of ~40 μm s(-1).

  1. Magnetic/pH-sensitive κ-carrageenan/sodium alginate hydrogel nanocomposite beads: preparation, swelling behavior, and drug delivery.

    PubMed

    Mahdavinia, Gholam Reza; Rahmani, Zeinab; Karami, Shiva; Pourjavadi, Ali

    2014-01-01

    This work describes the preparation of magnetic and pH-sensitive beads based on κ-carrageenan and sodium alginate for use as drug-targeting carriers. Physical cross-linking using K(+)/Ca(2+) ions was applied to obtain ionic cross-linked magnetic hydrogel beads. The produced magnetite beads were thoroughly characterized by TEM, SEM/EDS, XRD, FTIR, and VSM techniques. While the water absorbency (WA) of magnetic beads was enhanced by increasing the weight ratio of κ-carrageenan, introducing magnetic nanoparticles caused a decrease in WA capacity from 15.4 to 6.3 g/g. Investigation on the swelling of the hydrogel beads in NaCl, KCl, and CaCl2 solutions revealed the disintegration of beads depending on the composition of hydrogel beads and the type of metal cations in swelling media. The swelling ratio of beads indicated pH-dependent properties with maximum water absorbing at pH 7.4. Also, it was found that the strength of pH-sensitivity of magnetic beads was low for beads with the high content of carrageenan component. The in vitro drug release studies from hydrogels exhibited significant behaviors on the subject of physiological-simulated pH values and external magnetic fields. The maximum cumulative releases obtained were 98 and 43% at pH values 7.4 and 1.2, respectively. The Introducing magnetite nanoparticles influenced the cumulative release of drug. PMID:25197770

  2. Transition from downward to upward air-sea momentum transfer in swell-dominated light wind condition

    NASA Astrophysics Data System (ADS)

    Smedman, Ann-Sofi; Högström, Ulf; Rutgersson, Anna

    2016-04-01

    Atmospheric and surface wave data from two oceanic experiments carried out on FLIP and ASIS platforms are analysed in order to identify swell-related effects on the momentum exchange during low wind speed conditions. The RED experiment was carried out on board an R/P Floating Instrument Platform, FLIP, anchored north east of the Hawaiian island Oahu with sonic anemometers at four levels: 5.1 m, 6.9 m, 9.9 m and 13.8 m respectively. The meteorological conditions were characterized by north- easterly trade wind and with swell present during most of the time. During swell the momentum flux was directed downwards meaning a positive contribution to the stress. The FETCH experiment was carried out in the Gulf of Lion in the north-western Mediterranean Sea. On the ASIS (air-sea interaction spar) buoy a sonic anemometer was mounted at 7 m above the mean surface level. During strong swell conditions the momentum flux was directed upwards meaning a negative contribution to the stress in this case. The downward momentum flux is shown to be a function of the orbital circulation while the upward momentum flux is a function of wave height. The dividing wind speed is found to be 3.5 m/s Conclusion: Wind speed > 3.5 m/s creates waves (ripples) and thus roughness. Combination of orbital motion and asymmetric structure of ripples lead to flow perturbation and downward transport of negative momentum. With low wind speed (no ripples but viscosity) circulations will form above the crest and the trough with opposite direction which will cause a pressure drop in the vertical direction and an upward momentum transport from the water to the air.

  3. Effect of initial total monomer concentration on the swelling behavior of cationic acrylamide-based hydrogels

    SciTech Connect

    Baker, J.P.; Hong, L.H.; Blanch, H.W.; Prausnitz, J.M. . Dept. of Chemical Engineering Lawrence Berkeley Lab., CA . Chemical Sciences Div.)

    1994-03-14

    The aqueous equilibrium swelling properties of a series of lightly-cross-linked cationic hydrogels based on acrylamide and [(methacrylamido) propyl] trimethylammonium chloride (MAPTAC) were measured as a function of initial total monomer concentration % T (w/v) and ionic strength. Swelling is a strong decreasing function of rising % T; the 10 % T hydrogel obtained a 17-fold larger swelling ratio (g of swollen hydrogel/g of dry hydrogel) in pure water compared to the 40 % T hydrogel. Good agreement is obtained between measured swelling equilibria in aqueous sodium chloride and that calculated from a Flory-type swelling model including ideal Donnan equilibria provided that an adjustable parameter is introduced into the swelling model for hydrogels in pure water. The experimental results presented here indicate that network-chain interpenetration increases with rising % T.

  4. A new insight from space into swell propagation and crossing in the global oceans

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Ming

    2016-05-01

    A half-century ago, it was recorded that ocean swells can propagate up to halfway around the globe. However, from a global perspective, how ocean swells propagate in the global oceans has yet to be depicted. To date, synthetic aperture radar (SAR) is the only available remote sensing instrument to measure the two-dimensional information of ocean surface waves. Here a 10 year (2002-2012) global wave data set of the spaceborne advanced SAR on board the European Space Agency's satellite Envisat and the global wind data set of the WindSat were used to (1) depict the propagation routes of ocean swells in the global oceans, (2) identify four distinguished crossing swell "pools," and (3) interpret how these pools are formed. Together, these findings yield a new insight into ocean swells propagation and the consequent occurrence of crossing swells on a global ocean scale from space, which will further deepen our understanding of nature of ocean.

  5. 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.

  6. The correlation between swelling and radiation-induced segregation in iron-chromium-nickel alloys.

    SciTech Connect

    Allen, T. R.; Busby, J. T.; Kenik, E. A.; Was, G. S.

    1998-03-05

    The magnitudes of both void swelling and radiation-induced segregation (RIS) in iron-chromium-nickel alloys are dependent on bulk alloy composition. Because the diffusivity of nickel via the vacancy flux is slow relative to chromium, nickel enriches and chromium depletes at void surfaces during irradiation. This local composition change reduces the subsequent vacancy flux to the void, thereby reducing void swelling. In this work, the resistance to swelling from major element segregation is estimated using diffusivities derived from grain boundary segregation measurements in irradiated iron-chromium-nickel alloys. The resistance to void swelling in iron- and nickel-base alloys correlates with the segregation and both are functions of bulk alloy composition. Alloys that display the greatest amount of nickel enrichment and chromium depletion are found to be most resistant to void swelling, as predicted. Additionally, swelling is shown to be greater in alloys in which the RIS profiles are slow to develop.

  7. Microscale Patterning of Thermoplastic Polymer Surfaces by Selective Solvent Swelling

    PubMed Central

    Rahmanian, Omid; Chen, Chien-Fu; DeVoe, Don L.

    2012-01-01

    A new method for the fabrication of microscale features in thermoplastic substrates is presented. Unlike traditional thermoplastic microfabrication techniques, in which bulk polymer is displaced from the substrate by machining or embossing, a unique process termed orogenic microfabrication has been developed in which selected regions of a thermoplastic surface are raised from the substrate by an irreversible solvent swelling mechanism. The orogenic technique allows thermoplastic surfaces to be patterned using a variety of masking methods, resulting in three-dimensional features that would be difficult to achieve through traditional microfabrication methods. Using cyclic olefin copolymer as a model thermoplastic material, several variations of this process are described to realize growth heights ranging from several nanometers to tens of microns, with patterning techniques include direct photoresist masking, patterned UV/ozone surface passivation, elastomeric stamping, and noncontact spotting. Orogenic microfabrication is also demonstrated by direct inkjet printing as a facile photolithography-free masking method for rapid desktop thermoplastic microfabrication. PMID:22900539

  8. 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.

  9. Mechanical and swelling properties of PDMS interpenetrating polymer networks

    NASA Astrophysics Data System (ADS)

    Cohen, Claude; Yoo, Seong Hyun

    2006-03-01

    Poly(dimethylsiloxane) (PDMS) interpenetrating networks (IPNs) of a large and a small molar mass PDMS were prepared. Six series of IPNs were obtained by first tetra-functionally end-linking long vinyl-terminated PDMS neat or in a 50 per cent solution with unreactive PDMS chains. These networks were then dried and swollen with short reactive telechelic PDMS that were subsequently end-linked. We found that the correlation between modulus (E) and equilibrium swelling (Q) in toluene of the PDMS IPNs obeys a scaling relation identical to that of normal uni-modal PDMS networks. The results of the toughness of the networks represented by the energy required to rupture them were analyzed in terms of a recent model by Okumura (Europhysics Letters 67(3), 470, 2004). A modified version of this model that assumes each component of the double network to be subjected to an equal stress gives a good representation of the data.

  10. Co-hydrogasification of lignocellulosic biomass and swelling coal

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Zheng, N.; Wang, J.

    2016-08-01

    The hydrogasification of pine wood (PW) and rice husk (RH) was carried out in a two-stage fixed-bed reactor to investigate the effects of hydrogen pressure and hydrocracking temperature on the yields of gas and tar compositions. The elevation in hydrogen pressure promoted the conversion of two biomasses, leading to the improvement in gaseous hydrocarbons but resulted in a decrease in the yield of BTX (benzene, toluene and xylene). The increased severity of hydrocracking boosted the yield of methane, ethane and BTX mainly at the expense of heavy compounds in tar for PW under 1 MPa. The co-hydrogasification of biomass and DWG swelling coal chiefly showed a synergistic effect on the yields of BTX and PCX (phenol, cresol and xylenol) at 500 °C hydrocracking temperature under 5 MPa.

  11. Idiopathic facial swelling secondary to sickle cell anaemia

    PubMed Central

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

    2012-01-01

    Sickle cell disease is a common inherited autosomal disease that is characterised by abnormally shaped (sickle-shaped) red blood cells (RBCs). It can involve virtually any organ system. The clinical manifestations of sickle cell disease vary and are classified as vaso-occlusion, chronic anaemia and infection. The imaging appearances of central nervous system and musculoskeletal involvement by sickle cell disease have been well documented; however, involvement of the head and neck region is often unreported, although it is not uncommon. In the head and neck, sickle cell disease can involve the inner ears, orbits, paranasal sinuses, bones, lymph nodes and vessels. This paper describes a case of idiopathic facial swelling associated with sickle cell disease in a young patient. PMID:23060382

  12. Magnetic resonance imaging of clays: swelling, sedimentation, dissolution

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey; Furo, Istvan

    2010-05-01

    measure of clay distribution in extended samples during different physical processes such as swelling, dissolution, and sedimentation on the time scale from minutes to years [1-3]. To characterize the state of colloids that form after/during clay swelling the water self-diffusion coefficient was measured on a spatially resolved manner. Both natural clays and purified and ion-exchanged montmorillonite clays were investigated. The primary variables were clay composition and water ionic strength. These results have a significant impact for engineering barriers for storage of spent nuclear fuel where clay erosion by low salinity water must be addressed. Presented methods were developed under the motivation of using bentonite clays as a buffer medium to build in-ground barriers for the encapsulation of radioactive waste. Nevertheless, the same approaches can be found suitable in other applications in soil and environmental science to study other types of materials as they swell, dissolve, erode, or sediment. Acknowledgements: This work has been supported by the Swedish Nuclear Fuel and Waste Management Co (SKB) and the Swedish Research Council VR. [1] N. Nestle, T. Baumann, R. Niessner, Magnetic resonance imaging in environmental science. Environ. Sci. Techn. 36 154A (2002). [2] S. V. Dvinskikh, K. Szutkowski, I. Furó. MRI profiles over a very wide concentration ranges: application to swelling of a bentonite clay. J. Magn. Reson. 198 146 (2009). [3] S. V. Dvinskikh, I. Furó. Magnetic resonance imaging and nuclear magnetic resonance investigations of bentonite systems. Technical Report, TR-09-27, SKB (2009), www.skb.se.

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  14. Adsorption-induced coal swelling and stress: Implications for methane production and acid gas sequestration into coal seams

    NASA Astrophysics Data System (ADS)

    Cui, Xiaojun; Bustin, R. Marc; Chikatamarla, Laxmi

    2007-10-01

    Sequestration of CO2 and H2S into deep unminable coal seams is an attractive option to reduce their emission into atmosphere and at the same time displace preadsorbed CH4 which is a clean energy resource. High coal seam permeability is required for efficient and practical sequestration of CO2 and H2S and recovery of CH4. However, adsorption of CO2 and H2S into coals induces strong swelling of the coal matrix (volumetric strain) and thus reduces significantly coal permeability by narrowing and even closing fracture apertures. Our experimental data on three western Canadian coals show that the adsorption-induced volumetric strain is approximately linearly proportional to the volume of adsorbed gas, and for the same gas, different coals have very similar volumetric strain coefficient. Impacts of adsorption-induced swelling on stress and permeability around wellbores were analytically investigated using our developed stress and permeability models. Our model results indicate that adsorption-induced volumetric strain has significant controls on stress and permeability of producing and sequestrating coal seams and consequently the potential of acid gas sequestration. Coal seams may undergo >10 times enhancement of permeability around CH4-producing wellbores due to a reduction in effective stress as a result of coal shrinking caused by methane desorption accompanying a reduction in reservoir pressure. Injection of H2S and CO2 on the other hand results in strong sorption-induced swelling and a marked increase in effective stress which in turn leads to a reduction of coal seam permeability of up to several orders of magnitude. Injection of mixtures of N2 and CO2 such as found in flue gas results in weaker swelling, the amount of which varies with gas composition, and provides the greatest opportunity of sequestering CO2 and secondary recovery of CH4 for most coals. Because of the marked swelling of coal in the presence of H2S, even minor amounts of H2S result in a marked

  15. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization.

    PubMed

    Sen, Swati; Kundagrami, Arindam

    2015-12-14

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton's law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization. PMID:26671401

  16. 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.

  17. 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.

  18. 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.

  19. Map Showing Areas Containing Swelling Clay in the Morrison Quadrangle, Jefferson County, Colorado

    USGS Publications Warehouse

    Scott, Glenn R.

    1972-01-01

    Formations that contain clays having swelling pressures higher than 2,500 pounds per square foot (as measured by the Potential Volume Change meter) are listed in order of decreasing swelling pressure: Denver Formation, Pierre Shale, Laramie Formation, Green Mountain Conglomerate, Fox Hills Sandstone, and Arapahoe Formation. Some landslides derived from these formations also contain swelling clay and are mapped with the bedrock formations listed above.

  20. 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.

  1. Experimental investigation of stress effect on swelling and microstructure of Fe-16Cr-15Ni-3Mo-Nb austenitic stainless steel under low-temperature irradiation up to high damage dose in the BOR-60 reactor

    NASA Astrophysics Data System (ADS)

    Neustroev, V. S.; Ostrovsky, Z. E.; Shamardin, V. K.

    2004-08-01

    The present paper was devoted to investigation of the stress effect on swelling and microstructure evolution of the Fe-15.8Cr-15.3Ni-2.8Mo-0.6Nb steel irradiated in the BOR-60 reactor at temperatures from 395 to 410 °C and damage doses from 79 to 98 dpa. Was found out that the stress increase leads to an increase of swelling, that can be associated with a decrease in incubation period with a practically constant swelling rate. Voids concentration increases at the first stage of irradiation when the void sizes are practically constant, and then the concentration reaches some saturation and swelling increase is caused by void growth.

  2. Eddy current sensor for in-situ monitoring of swelling of Li-ion prismatic cells

    SciTech Connect

    Plotnikov, Yuri Karp, Jason Knobloch, Aaron Kapusta, Chris Lin, David

    2015-03-31

    In-situ monitoring an on-board rechargeable battery in hybrid cars can be used to ensure a long operating life of the battery and safe operation of the vehicle. Intercalations of ions in the electrode material during charge and discharge of a Lithium Ion battery cause periodic stress and strain of the electrode materials that can ultimately lead to fatigue resulting in capacity loss and potential battery failure. Currently this process is not monitored directly on the cells. This work is focused on development technologies that would quantify battery swelling and provide in-situ monitoring for onboard vehicle applications. Several rounds of tests have been performed to spatially characterize cell expansion of a 5 Ah cell with a nickel/manganese/cobalt-oxide cathode (Sanyo, Japan) used by Ford in their Fusion HEV battery pack. A collaborative team of researchers from GE and the University of Michigan has characterized the free expansion of these cells to be in the range of 100×125 microns (1% of total cell thickness) at the center point of the cell. GE proposed to use a thin eddy current (EC) coil to monitor these expansions on the cells while inside the package. The photolithography manufacturing process previously developed for EC arrays for detecting cracks in aircraft engine components was used to build test coils for gap monitoring. These sensors are thin enough to be placed safely between neighboring cells and capable of monitoring small variations in the gap between the cells. Preliminary investigations showed that these coils can be less than 100 micron thick and have sufficient sensitivity in a range from 0 to 2 mm. Laboratory tests revealed good correlation between EC and optical gap measurements in the desired range. Further technology development could lead to establishing a sensor network for a low cost solution for the in-situ monitoring of cell swelling during battery operation.

  3. Eddy current sensor for in-situ monitoring of swelling of Li-ion prismatic cells

    NASA Astrophysics Data System (ADS)

    Plotnikov, Yuri; Karp, Jason; Knobloch, Aaron; Kapusta, Chris; Lin, David

    2015-03-01

    In-situ monitoring an on-board rechargeable battery in hybrid cars can be used to ensure a long operating life of the battery and safe operation of the vehicle. Intercalations of ions in the electrode material during charge and discharge of a Lithium Ion battery cause periodic stress and strain of the electrode materials that can ultimately lead to fatigue resulting in capacity loss and potential battery failure. Currently this process is not monitored directly on the cells. This work is focused on development technologies that would quantify battery swelling and provide in-situ monitoring for onboard vehicle applications. Several rounds of tests have been performed to spatially characterize cell expansion of a 5 Ah cell with a nickel/manganese/cobalt-oxide cathode (Sanyo, Japan) used by Ford in their Fusion HEV battery pack. A collaborative team of researchers from GE and the University of Michigan has characterized the free expansion of these cells to be in the range of 100×125 microns (1% of total cell thickness) at the center point of the cell. GE proposed to use a thin eddy current (EC) coil to monitor these expansions on the cells while inside the package. The photolithography manufacturing process previously developed for EC arrays for detecting cracks in aircraft engine components was used to build test coils for gap monitoring. These sensors are thin enough to be placed safely between neighboring cells and capable of monitoring small variations in the gap between the cells. Preliminary investigations showed that these coils can be less than 100 micron thick and have sufficient sensitivity in a range from 0 to 2 mm. Laboratory tests revealed good correlation between EC and optical gap measurements in the desired range. Further technology development could lead to establishing a sensor network for a low cost solution for the in-situ monitoring of cell swelling during battery operation.

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

    PubMed

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

    2009-05-22

    The sexual swellings of female primates have generated a great deal of interest in evolutionary biology. Two hypotheses recently proposed to elucidate their functional significance argue that maximal swelling size advertises either female fertility within a cycle or female quality across cycles. Published evidence favours the first hypothesis, and further indicates that larger swellings advertise higher fertility between cycles. If so, a male preference for large swellings might evolve, driving females to use swellings as quality indicators, as proposed by the second hypothesis. In this paper, we explore this possibility using a combination of empirical field data and mathematical modelling. We first test and find support for three key predictions of the female-quality hypothesis in wild chacma baboons (Papio ursinus): (i) inter-individual differences in swelling size are maintained across consecutive cycles, (ii) females in better condition have larger swellings and higher reproductive success, and (iii) males preferentially choose females with large swellings. We then develop an individual-based simulation model that indicates that females producing larger swellings can achieve higher mating success even when female-female competition is low and within-female variance in the trait is high. Taken together, our findings show that once sexual swellings have evolved as fertility signals, they might, in certain socio-sexual systems, be further selected to act as quality signals. These results, by reconciling two hypotheses, help to clarify the processes underlying sexual swelling evolution. More generally, our findings suggest that mate choice for direct benefits (fertility) can lead to indirect benefits (good genes).

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Domal uplifts, volcanism, basin formation and rifting have often struck the same continent in different areas at the same time. Their characteristics and orientations are difficult to reconcile with mantle convection or tectonic forces and suggest a driving mechanism that is intrinsic to the continent. The rifts seem to develop preferentially at high angles to the edge of the continent whereas swells and basins seem confined to the interior. Another intriguing geometrical feature is that the rifts often branch out in complicated patterns at their landward end. In Western Africa, for example, magmatic activity currently occurs in a number of uplifted areas including the peculiar Cameroon Volcanic Line that stretches away from the continental margin over about 1000 km. Magmatic and volcanic activity has been sustained along this line for 70 My with no age progression. The mantle upwelling that feeds the volcanoes is not affected by absolute plate motions and hence is attached to the continent. The Cameroon Volcanic Line extends to the Biu swell to the North and the Jos plateau to the West defining a striking Y-shaped pattern. This structure segues into several volcanic domes including the Air, the Hoggar, the Darfur, the Tibesti and the Haruj domes towards the Mediterranean coast. Another example is provided by North America, where the late Proterozoic-early Ordovician saw the formation of four major basins, the Michigan, Illinois, Williston and Hudson Bay, as well as of major rifts in southern Oklahoma and the Mississipi Valley within a short time interval. At the same time, a series of uplifts developed, such as the Ozark and Nashville domes. Motivated by these observations, we have sought an explanation in the continental lithosphere itself. 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

  6. French Polynesia Hotspot Swells Explained By Dynamic Topography

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  7. 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.

  8. [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.

  9. A mechanism of swelling suppression in phosphorous-modified Fe-Ni-Cr alloys*1

    NASA Astrophysics Data System (ADS)

    Lee, E. H.; Mansur, L. K.

    1986-11-01

    Five simple alloys were ion irradiated at 948 K in an experiment designed to investigate the mechanism of swelling suppression associated wtih phosphorous additions. One of the alloys was the simple ternary Fe-15Ni-13Cr, another had 0.05% P added and the other three had further additions of the phosphide precipitate-forming elements Ti and/or Si. Ion irradiations were carried out with heavy ions only (Ni or Fe) or with heavy ions followed by dual heavy ions and helium. The ternary with and without P swelled readily early in dose with or without helium. The other three alloys only showed swelling in the presence of helium and exhibited a long delay in dose prior to the onset of swelling. These displayed fine distributions of Fe 2P type phosphide precipitates enhanced by irradiation. The phosphide particles gave rise to very high concentrations of stable helium filled cavities at the precipitate matrix interfaces. The results were analyzed in terms of the theory of cavity swelling. The accumulation of the critical number of gas atoms in an individual cavity is required in the theory for point defect driven swelling to begin. It is concluded that the primary mechanism leading to swelling suppression is therefore the dilution of injected helium over a very large number of cavities. It is suggested that this mechanism may offer a key for alloy design for swelling resistance in high helium environments.

  10. 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.

  11. 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...

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

    PubMed

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

    2009-12-01

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

  13. Slow growing, painful, nodular swelling on the buccal mucosa: a case report.

    PubMed

    Austin, Ravi David; Mathew, Philips; Rajathi, Maria J; Murugan, Kandasamy

    2014-01-01

    Nodular swellings of the oral cavity are frequently encountered in dental practice. The disease processes that give rise to nodular swellings in the oral cavity include inflammatory hyperplasias, obstructive minor salivary gland disorders, infections, benign connective tissue neoplasms and salivary gland neoplasms. Understandably, the nature of these entities also varies significantly, ranging from very innocuous to aggressive lesions, underscoring the need for accurate diagnosis.

  14. 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.

  15. 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.

  16. Nanoscale Swelling Heterogeneities in Type I Collagen Fibrils.

    PubMed

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

    2015-06-23

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

  17. Increased Hydrogel Swelling Induced by Absorption of Small Molecules.

    PubMed

    Nam, Changwoo; Zimudzi, Tawanda J; Geise, Geoffrey M; Hickner, Michael A

    2016-06-01

    The water and small molecule uptake behavior of amphiphilic diacrylate terminated poly(dimethylsiloxane) (PDMSDA)/poly(ethylene glycol diacrylate) (PEGDA) cross-linked hydrogels were studied using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. These hydrogel networks absorbed more water as the PEGDA content of the network increased. In contrast to typical osmotic deswelling behavior that occurs when liquid water equilibrated hydrogels are immersed in small molecule solutions with water activities less than unity, water-swollen gels immersed in 2-acrylamido-2-methylpropanesulfonic acid (AMPS-H) solutions rapidly regained their water content within 4 min following an initial deswelling response. In situ ATR-FTIR analysis of the hydrogel film during the dynamic swelling experiment indicated that small molecule absorption into the gel played an important role in inducing gel reswelling in low water activity solutions. This aspect of polymer gel water uptake and interaction with small molecules is important for optimizing hydrogel coatings and hydrophilic polymer applications where there is an interaction between the internal chemical structure of the gel and electrolytes or other molecules in solution. PMID:27159118

  18. 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.

  19. 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.

  20. Inversion of swell frequency from a 1-year HF radar dataset collected in Brittany (France)

    NASA Astrophysics Data System (ADS)

    Wang, Weili; Forget, Philippe; Guan, Changlong

    2014-10-01

    This article presents long period ocean wave (swell) frequencies inverted from a 13-month dataset of high-frequency (HF) phased array radars and an assessment of these estimates by comparison with WAVEWATCH III model data. The method of swell frequency inversion from high-frequency radar sea echo Doppler spectra is described. Radar data were collected from a two-site HF Wellen Radar (WERA) radar system on the west coast of Brittany (France) operating at 12 MHz. A standard beam-forming processing technique has been used to obtain Doppler spectra of processed radar cells. Swell frequencies are obtained from the frequencies of particular spectral peaks of the second-order continuum in hourly averaged Doppler spectra. The data coverage of effective Doppler spectra considered for swell frequency estimates shows the influence of islands and shallow water effects. Swell estimates from both radar stations are in good agreement. The comparison of radar-derived results to WAVEWATCH III (WW3) estimates shows that radar measurements agree quite well with model results. The bias and standard deviation between two estimates are very small for swells with frequency less than 0.09 Hz (period >11 s), whereas radar estimates are generally lower than model estimates for shorter swells, along with higher standard deviation. Statistical analysis suggests that radar measurement uncertainty explains most of the difference between radar and model estimates. For each swell event, time series of frequency exhibits a quasi-linear frequency increase which is associated with the dispersive property of wave phase velocity. The use of swell frequency estimates from both radars on common radar cells only slightly increases the accuracy of swell frequency measurement.

  1. 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.

  2. 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.

  3. Shrinking and swelling clays under droughts: measurements at the Mormoiron test-site and first analyses (Vaucluse, South-East of France)

    NASA Astrophysics Data System (ADS)

    Gourdier, Sébastien; Vandromme, Rosalie; Grandjean, Gilles

    2013-04-01

    In France, exceptional periods of rainfall deficit (1976, 1989 to 1991 and 1996 to 1997) have caused damages to houses due to their vulnerability to shrinking and swelling clays phenomenon. Between 1998 and 2010, BRGM has been producing a national hazard map related to shrinking and swelling clays, built by crossing geological data and information on density of damages for each geological formation (methodology developed since 1995). The intense drought of summer 2003 has pointed out the necessity of a better understanding of this phenomenon. At the request of the French Ministry of Environment, BRGM has developed a new method for measuring the moisture evolution with depth in order to study its impact on the swelling capacity of clayed soil. The site of Mormoiron (Vaucluse, South-East of France) has then been instrumented for that purpose, with moisture sensors (since December 2004) and extensometers (since March 2009) at different depths. These data have been used to test and improve existing empirical models which are supposed to assess settlements and swellings, depending on the soil water content. Compilations of different measurements have shown, after basic processing made on the data (filtering, resampling, etc.), evident correlations between rain and surface displacements. The model finally obtained gives quite good dependence between these two quantities for the uppermost soil layers (0.2m and 0.5m). More research are being undertaken to physically explain this relationship, particularly for deeper layers. These results should lead to propose a calibrated model for predicting soil deformations from climatic data.

  4. [A lupus-vulgaris like atypical mycobacteriosis caused by Mycobacterium xenopi (lupus xenopi)].

    PubMed

    Kiehl, P; Eicher, U; Vakilzadeh, F

    1992-09-01

    A case of lupus-vulgaris-like infection caused by Mycobacterium xenopi in a 62-year-old immunocompetent female patient is presented. A large cutaneous infiltration was seen in the right periorbital region. Histological examination revealed a granulomatous reaction of epithelioid cells and giant cells. M. xenopi was isolated from biopsy material and tuberculosis could be excluded. Isoniazid was effective in healing the lesion within a year. Such infections are well known for other mycobacteria but to our knowledge had not yet been described for M. xenopi. The characteristics of human infections with M. xenopi are summarized in a review of the literature and criteria for the diagnosis of atypical cutaneous mycobacterioses are proposed.

  5. Cell swelling has differential effects on the rapid and slow components of delayed rectifier potassium current in guinea pig cardiac myocytes

    PubMed Central

    1995-01-01

    Cell swelling has been shown to cause activation of a variety of cardiac sarcolemmal ionic conductances including potassium channels. The aim of this study was to investigate the effect of swelling on the two subtypes of delayed rectifier potassium current (IKr and IKs) in single guinea pig myocytes using the whole-cell configuration of the patch clamp technique. When the holding potential was set at -40 mV and stepped to +40 mV for 1 s under isoosmotic conditions (300 mOsm) a delayed rectifier current (IK) was activated (0.86 +/- 0.05 nA; n = 43). Switching to a hypoosmotic solution (200 mOsm) caused a rapid increase in IK to a mean value of 1.43 +/- 0.10 nA (p < 0.05; n = 43). The effect of swelling on the two subtypes of IK was studied by analysis of deactivating tail currents using an envelope of tails protocol (stepping from -40 to +40 mV for 18 different pulse durations between 50 ms and 2.9 s; n = 16). Swelling caused a decrease in current amplitude measured at the end of the pulse (and IKtail) at short durations (< or = 150 ms) however, when the pulse duration was > 1 s swelling caused a significant increase in current. Using a pulse protocol to measure IKr with minimal contamination by IKs (voltage step from -40 to -10 mV for 250 ms) a 50-100 pA current was elicited which could be completely blocked by dofetilide (0.2 microM; n = 3). Introduction of hypoosmotic solution caused a significant decrease in IKr and when dofetilide (0.2 or 1.0 microM) was introduced the current remaining was decreased further (p < 0.05; n = 5), but was not completely blocked, thus suggesting that swelling had decreased the ability of dofetilide to block IKr. Similar results were obtained over a range of dofetilide concentrations and with a second IKr blocker, La3+. In Ca(2+)-free external solutions, pulsing to -10 mV for 500 ms to measure IKr in the absence of IKs, and to +60 mV for 5 s (with 0.2 microM dofetilide) to evoke only IKs, it was clear that swelling significantly

  6. 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.)

  7. 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

  8. Molecular accessibility in solvent swelled coals. Quarterly report, [September--November, 1993

    SciTech Connect

    Kispert, L.D.

    1993-11-01

    This quarter, experiments were performed on the use of binary swelling solvents in molecular accessibility in coal conversion. These experiments consisted of accessibility measurements of spin probe VII (TEMPAMINE) in Toluene swelled Illinois No. 6 APCS coal. The toluene was spiked with amounts of pyridine which ranged in concentration from 500 ppm to 10%. The experiments were done in triplicate to gain information about the experimental error involved in the procedure. It was shown that oscillations occur in the concentration of spin probe retained as the amount of pyridine that is added to the swelling solvent is increased. These oscillations decrease in intensity as the concentration of pyridine in the solvent solution is increased up to 2% pyridine (0.2mLs pyridine in 10mLs toluene). From a 2% pyridine concentration to a 5% concentration, there is no significant change in the retention of spin probe VII. An increase in retention is observed when the concentration of pyridine is increased to 6% and 7% successively, followed by a large decrease at 8% and 9% pyridine. The largest changes in spin probe retention are observed for concentrations of pyridine less than 0.5%. A three fold increase in spin probe retention is observed upon the addition of 500 ppm pyridine in the toluene swelling solvent, which indicates that small amounts of a strong swelling solvent could be used to improve molecular accessibility 91% in coals swelled in an otherwise weak swelling solvent.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Deformation mechanisms in a coal mine roadway in extremely swelling soft rock.

    PubMed

    Li, Qinghai; Shi, Weiping; Yang, Renshu

    2016-01-01

    The problem of roadway support in swelling soft rock was one of the challenging problems during mining. For most geological conditions, combinations of two or more supporting approaches could meet the requirements of most roadways; however, in extremely swelling soft rock, combined approaches even could not control large deformations. The purpose of this work was to probe the roadway deformation mechanisms in extremely swelling soft rock. Based on the main return air-way in a coal mine, deformation monitoring and geomechanical analysis were conducted, as well as plastic zone mechanical model was analysed. Results indicated that this soft rock was potentially very swelling. When the ground stress acted alone, the support strength needed in situ was not too large and combined supporting approaches could meet this requirement; however, when this potential released, the roadway would undergo permanent deformation. When the loose zone reached 3 m within surrounding rock, remote stress p ∞ and supporting stress P presented a linear relationship. Namely, the greater the swelling stress, the more difficult it would be in roadway supporting. So in this extremely swelling soft rock, a better way to control roadway deformation was to control the releasing of surrounding rock's swelling potential. PMID:27547684

  14. 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.

  15. 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.

  16. Overcoming confinement limited swelling in hydrogel thin films using supramolecular interactions.

    PubMed

    Wiener, Clinton G; Weiss, R A; Vogt, Bryan D

    2014-09-21

    The thin film behavior of poly(N-isopropylacrylamide-stat-2-(N-ethylperfluorooctane sulfonamido)ethyl acrylate) (NIPAAm-stat-FOSA) based hydrogels containing 5 mol% FOSA was elucidated using quartz crystal microbalance with dissipation (QCM-D) in combination with spectroscopic ellipsometry (SE) through examination of the lower critical solution temperature (LCST) and temperature dependent swelling for (dry) thicknesses ranging from 10 nm to 121 nm. For all thin films measured, the LCST was shown to slightly increase (>3 °C) in comparison to that of the bulk sample. However for these films, the increase in LCST was statistically identical, irrespective of thickness. Surprisingly, the volumetric swelling of the hydrogel in thin films, even at temperatures less than the LCST, was similar (within 20%) to the volumetric swelling of the bulk hydrogel, despite the expected significant decrease associated with the hydrogel being constrained by the substrate as predicted by one dimensional Flory-Rehner theory. We attribute this enhancement in swelling compared to theoretical expectations to the ability of the hydrophobic crosslinks to re-arrange under stress, which provides a mechanism to alleviate the decreased dimensionality imposed by the substrate; this mechanism is consistent with a large hysteresis in the swelling when cycling between 35 °C and 5 °C. Unlike the LCST, the swelling ratio increases with decreasing film thickness. At low temperatures (below the LCST), the volume swelling ratio increased from 3.9 to 4.9, while at temperatures above the LCST the swelling ratio increased from 1.5 to 2.5 when the film thickness decreased from 121 nm to 10 nm. The combination of facile processing through solution casting without the need for additional crosslinking chemistry and limited thickness dependent variation of swelling and LCST behavior in these physically crosslinked hydrogels makes these materials attractive for applications requiring thermoresponsive soft

  17. Altered swelling and ion fluxes in articular cartilage as a biomarker in osteoarthritis and joint immobilization: a computational analysis

    PubMed Central

    Manzano, Sara; Manzano, Raquel; Doblaré, Manuel; Doweidar, Mohamed Hamdy

    2015-01-01

    In healthy cartilage, mechano-electrochemical phenomena act together to maintain tissue homeostasis. Osteoarthritis (OA) and degenerative diseases disrupt this biological equilibrium by causing structural deterioration and subsequent dysfunction of the tissue. Swelling and ion flux alteration as well as abnormal ion distribution are proposed as primary indicators of tissue degradation. In this paper, we present an extension of a previous three-dimensional computational model of the cartilage behaviour developed by the authors to simulate the contribution of the main tissue components in its behaviour. The model considers the mechano-electrochemical events as concurrent phenomena in a three-dimensional environment. This model has been extended here to include the effect of repulsion of negative charges attached to proteoglycans. Moreover, we have studied the fluctuation of these charges owning to proteoglycan variations in healthy and pathological articular cartilage. In this sense, standard patterns of healthy and degraded tissue behaviour can be obtained which could be a helpful diagnostic tool. By introducing measured properties of unhealthy cartilage into the computational model, the severity of tissue degeneration can be predicted avoiding complex tissue extraction and subsequent in vitro analysis. In this work, the model has been applied to monitor and analyse cartilage behaviour at different stages of OA and in both short (four, six and eight weeks) and long-term (11 weeks) fully immobilized joints. Simulation results showed marked differences in the corresponding swelling phenomena, in outgoing cation fluxes and in cation distributions. Furthermore, long-term immobilized patients display similar swelling as well as fluxes and distribution of cations to patients in the early stages of OA, thus, preventive treatments are highly recommended to avoid tissue deterioration. PMID:25392400

  18. Rhinosporidiosis of Parotid Duct Presenting as Consecutive Bilateral Facial Swelling: A Rare Case Report and Literature Review.

    PubMed

    Sarkar, Santanu; Panja, Soumyajyoti; Bandyopadhyay, Arghya; Roy, Shreosee; Kumar, Sandeep

    2016-03-01

    Rhinosporidiosis is a chronic granulomatous infection caused by Rhinosporidium seeberi. Sporadic cases of rhinosporidiosis has been reported from many countries but is endemic in Southern India (Madurai, Ramnad, Rajapalayam and Sivaganga), Nepal, Bangladesh and Sri Lanka. This disease commonly affects the mucous membrane of the nose or naso-pharynx and presents as a leafy, polypoidal mass. The reported extranasal sites include the oro-pharynx, eye, ear, larynx, trachea, bronchi, skin and genital mucosa. It may also become disseminated to present as a generalized form. In our case a 40-year-old female from rural West Bengal (Eastern India) presented with right sided facial swelling. Our provisional diagnosis was parotid duct cyst on the basis of careful history, scrupulous clinical examination and relevant investigations comprising CECT scan of face. Although Rhinosporidiosis was not taken into consideration in the clinical differential diagnosis, it was eventually diagnosed postoperatively by histopathological examination of surgical specimen. Two months later in follow-up, the same patient presented to us with left sided facial swelling. We managed the left facial swelling successfully with minimally invasive surgery and 100mg twice daily dapsone for 6 months. We present this case firstly because Rhinosporidiosis of parotid duct (stensen's duct) is a rare entity and secondly non-neoplastic cysts of the salivary glands are also uncommon and represent only 2-5% of all salivary gland lesions. Furthermore our case emphasizes that the clinicians should aware of this rare clinical entity specially in endemic areas, because minimally invasive techniques and medications might solve the problem while helping patients to avoid surgical excision. PMID:27134935

  19. Modeling swelling and absorption dynamics for holographic sensing in analytes sensitive photopolymer

    NASA Astrophysics Data System (ADS)

    Liu, Hongpeng; Yu, Dan; Mao, Dongyao; Geng, Yaohui; Wang, Weibo

    2016-06-01

    A theoretical model is developed to describe holographic sensing and swelling of grating fringe in photopolymer. In experiments, diffraction spectrum responses of grating are characterized to exhibit holographic sensing processes. Analytic expressions between swelling of grating fringe and environmental factors, such as relative humidity and organic vapor concentrations, are extracted based on experimental results. The primary factors are introduced into the model to simulate the sensing process, including swelling ratio, nanozeolites dispersion, and organic vapor absorption. Finally, numerical results are presented for improving the sensitivity of holographic sensor. This work can accelerate the development of holographic sensor and provide a theoretical base for exploring sensing mechanism of polymer.

  20. 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.

  1. Mitochondrial swelling and incipient outer membrane rupture in preapoptotic and apoptotic cells.

    PubMed

    Sesso, A; Belizário, J E; Marques, M M; Higuchi, M L; Schumacher, R I; Colquhoun, A; Ito, E; Kawakami, J

    2012-10-01

    Outer mitochondrial membrane (OMM) rupture was first noted in isolated mitochondria in which the inner mitochondrial membrane (IMM) had lost its selective permeability. This phenomenon referred to as mitochondrial permeability transition (MPT) refers to a permeabilized inner membrane that originates a large swelling in the mitochondrial matrix, which distends the outer membrane until it ruptures. Here, we have expanded previous electron microscopic observations that in apoptotic cells, OMM rupture is not caused by a membrane stretching promoted by a markedly swollen matrix. It is shown that the widths of the ruptured regions of the OMM vary from 6 to 250 nm. Independent of the perforation size, herniation of the mitochondrial matrix appeared to have resulted in pushing the IMM through the perforation. A large, long focal herniation of the mitochondrial matrix, covered with the IMM, was associated with a rupture of the OMM that was as small as 6 nm. Contextually, the collapse of the selective permeability of the IMM may precede or follow the release of the mitochondrial proteins of the intermembrane space into the cytoplasm. When the MPT is a late event, exit of the intermembrane space proteins to the cytoplasm is unimpeded and occurs through channels that transverse the outer membrane, because so far, the inner membrane is impermeable. No channel within the outer membrane can expose to the cytoplasm a permeable inner membrane, because it would serve as a conduit for local herniation of the mitochondrial matrix.

  2. Swelling and softening of lithium-ion battery separators in electrolyte solvents

    NASA Astrophysics Data System (ADS)

    Gor, Gennady Y.; Cannarella, John; Leng, Collen Z.; Vishnyakov, Aleksey; Arnold, Craig B.

    2015-10-01

    The mechanical stability of inactive polymeric components (e.g. separator and binder) can play an important role in the long term performance of lithium-ion batteries. Here we investigate the effects of electrolyte solvents on the mechanical properties of a polypropylene battery separator through experimental measurements of thickness and elastic modulus of separator samples immersed in different solvent environments. We find that certain electrolyte solvents such as dimethyl carbonate, diethyl carbonate, and ethyl acetate cause noticeable softening of the separator. However, in other solvent environments such as propylene carbonate and acetonitrile, the separator retains the mechanical properties of a dry material. We show that the mechanical property reduction can be attributed to polymer swelling and explain these observations in the context of the Hildebrand solubility and Flory-Huggins interaction parameters. The solubility/interaction parameter analysis provides a straightforward method for predicting the in situ mechanical behavior of polymer separators in solvent environments. The relationships discussed herein can be used to screen and identify mechanically-stable polymer and electrolyte solvent pairs for use in lithium-ion batteries designed for long life.

  3. Comprehensive Prediction of Large-height Swell-like Waves in East Coast of Korea

    NASA Astrophysics Data System (ADS)

    Kwon, S. J.; Lee, C.; Ahn, S. J.; Kim, H. K.

    2014-12-01

    There have been growing interests in the large-height swell-like wave (LSW) in the east coast of Korea because such big waves have caused human victims as well as damages to facilities such as breakwaters in the coast. The LSW was found to be generated due to an atmospherically great valley in the north area of the East Sea and then propagate long distance to the east coast of Korea in prominently southwest direction (Oh et al., 2010).In this study, we will perform two methods, real-time data based and numerical-model based predictions in order to predict the LSW in the east coast of Korea. First, the real-time data based prediction method uses information which is collected by the directional wave gauge installed near Sokcho. Using the wave model SWAN (Booij et al., 1999) and the wave ray method (Munk and Arthur, 1952), we will estimate wave data in open sea from the real-time data and predict the travel time of LSW from the measurement site (near Sokcho) to several target points in the east coast of Korea. Second, the numerical-model based method uses three different numerical models; WW3 in deep water, SWAN in shallow water, and CADMAS-SURF for wave run-up (CDIT). The surface winds from the 72 hours prediction system of NCEP (National Centers for Environmental Prediction) GFS (Global Forecast System) will be inputted in finer grids after interpolating these in certain domains of WW3 and SWAN models. The significant wave heights and peak wave directions predicted by the two methods will be compared to the measured data of LSW at several target points near the coasts. Further, the prediction method will be improved using more measurement sites which will be installed in the future. ReferencesBooij, N., Ris, R.C., and Holthuijsen, L.H. (1999). A third-generation wave model for coastal regions 1. Model description and validation. J. of Geophysical Research, 103(C4), 7649-7666.Munk, W.H. and Arthur, R.S. (1952). Gravity Waves. 13. Wave Intensity along a Refracted Ray

  4. Matrix Shrinkage and Swelling Effects on Economics of Enhanced Coalbed Methane Production and CO2 Sequestration in Coal

    SciTech Connect

    Gorucu, F.B.; Jikich, S.A.; Bromhal, G.S.; Sams, W.N.; Ertekin, T.; Smith, D.H.

    2005-09-01

    Increases in CO2 levels in the atmosphere and their contributions to global climate change have been a major concern. It has been shown that CO2 injection can enhance the methane recovery from coal. Accordingly, sequestration costs can be partially offset by the value added product. Indeed, coal seam sequestration may be profitable, particularly with the introduction of incentives for CO2 sequestration. Hence, carbon dioxide sequestration in unmineable coals is a very attractive option, not only for environmental reasons, but also for possible economic benefits. Darcy flow through cleats is an important transport mechanism in coal. Cleat compression and permeability changes due to gas sorption desorption, changes of effective stress, and matrix swelling and shrinkage introduce a high level of complexity into the feasibility of a coal sequestration project. The economic effects of carbon dioxide-induced swelling on permeabilities and injectivities has received little (if any) detailed attention. Carbon dioxide and methane have different swelling effects on coal. In this work, the Palmer-Mansoori model for coal shrinkage and permeability increases during primary methane production was re-written to also account for coal swelling caused by carbon dioxide sorption. The generalized model was added to PSU-COALCOMP, a dual porosity reservoir simulator for primary and enhanced coalbed methane production. A standard five-spot of vertical wells and representative coal properties for Appalachian coals were used.[1] Simulations and sensitivity analyses were performed with the modified simulator for nine different parameters, including coal seam and operational parameters and economic criteria. The coal properties and operating parameters that were varied included Young’s modulus, Poisson’s ratio, the cleat porosity, and the injection pressure. The economic variables included CH4 price, CO2 cost, CO2 credit, water disposal cost, and interest rate. Net present value analyses

  5. Swelling and Thermo-Mechanical Behavior of Smectitic Clay in the San Andreas Fault at Parkfield/California

    NASA Astrophysics Data System (ADS)

    Hofmann, H.; Schleicher, A. M.; van der Pluijm, B. A.

    2011-12-01

    water layer with an interlayer spacing of 2 nm, or higher ordering at higher temperatures. All measurements were reversible, reflecting the mineral's memory of natural conditions. Based on our experiments we conclude that i) Mg-rich smectite is stable at least up to 95°C, a temperature close to the depths where the sample was collected, ii) swelling is not affected by increasing temperature, showing that swelling occurs at ~3km depth, iii) particle orientation increases with increasing humidity, suggesting a higher mobility of the single smectite particles caused by the hydration of interlayer cations. With water available at depth and at temperatures of~ 110°C , swelling properties of smectitic gouge material is not negatively affected at these conditions. As interlayer and interparticle friction decreases with increasing water content, the swelling properties of these clays will reduce friction of the fault gouge and thus promote fault creep .

  6. Reversible swelling of the cell wall of poplar biomass by ionic liquid at room temperature

    PubMed Central

    Lucas, Marcel; Wagner, Greg L.; Nishiyama, Yoshiharu; Hanson, Leif; Samayam, Indira P.; Schall, Constance A.; Langan, Paul; Rector, Kirk D.

    2012-01-01

    Time-resolved autofluorescence, Raman microspectroscopy, and scanning microprobe X-ray diffraction were combined in order to characterize lignocellulosic biomass from poplar trees and how it changes during treatment with the ionic liquid 1-n-ethyl-3-methylimidazolium acetate (EMIMAC) at room temperature. The EMIMAC penetrates the cell wall from the lumen, swelling the cell wall by about a factor of two towards the empty lumen. However, the middle lamella remains unchanged, preventing the cell wall from swelling outwards. During this swelling, most of the cellulose microfibrils are solubi-lized but chain migration is restricted and a small percentage of microfibrils persist. When the EMIMAC is expelled, the cellulose recrystallizes as microfibrils of cellulose I. There is little change in the relative chemical composition of the cell wall after treatment. The action of EMIMAC on the poplar cell wall at room temperature would therefore appear to be a reversible swelling and a reversible decrystallization of the cell wall. PMID:21247757

  7. Patterned dual pH-responsive core-shell hydrogels with controllable swelling kinetics and volumes.

    PubMed

    Plunkett, Kyle N; Moore, Jeffrey S

    2004-08-01

    Dual pH-responsive core-shell hydrogels containing both a vinyl pyridine component and a 2-dimethylaminoethyl methacrylate component were prepared using an in situ photopolymerization process. Complementary photomasks were utilized to prepare hydrogels with core/shell volume ratios of 2:1, 1:1, and 1:2. Depending on the location of each polymer component, dramatically different swelling profiles were achieved. Selective swelling of the shell followed by the core components allowed the hydrogel to expand with the usual kinetics; however, by switching the location of each polymer component and swelling the core first, swelling rates decreased by over 1 order of magnitude and were dependent on the shell component's volume. The ability to pattern core/shell volumes also provided the ability to fabricate hydrogels that possess a constant maximum diameter but different cutoff points between its first and its second transition volumes. These materials may be of interest for controlled release applications. PMID:15274549

  8. Dissolution And Swelling Studies Of Poly(Methyl Methacrylate) Resist Films

    NASA Astrophysics Data System (ADS)

    Papanu, J. S.; Manjkow, J.; Hess, D. W.; Soong, D. S.; Bell, A. T.

    1987-08-01

    The swelling and dissolution of thin film poly(methyl methacrylate), PMMA, in methyl isobutyl ketone (MIBK), and in solvent/nonsolvent mixtures of MIBK/methanol and methyl ethyl ketone/isopropanol have been investigated. Films were monitored using in situ ellipsometry. Parametric studies of the effects of molecular weight, molecular weight distribution, softbaking quench rate, solvent size, and temperature were performed with MIBK. These parameters were shown to have a significant effect on dissolution. The effects of solvent composition and temperature on swelling and dissolution were investigated with the binary solvents. Ternary diagrams based on Flory-Huggins interaction parameters were used to interpret the thermodynamics of swelling and dissolution. A narrow transition region (NTR) where the developer changed from a swelling to dissolving agent with a small change in composition or temperature was observed.

  9. 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.

  10. 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.

  11. Bilayer mass transport model for determining swelling and diffusion in coated, ultrathin membranes.

    PubMed

    Nadermann, Nichole K; Chan, Edwin P; Stafford, Christopher M

    2015-02-18

    Water transport and swelling properties of an ultrathin, selective polyamide layer with a hydrophilic polymer coating, i.e., a polymer bilayer, are studied using quartz crystal microbalance with dissipation (QCM-D). Specifically, QCM-D is used to measure the dynamic and equilibrium change in mass in a series of differential sorption experiments to determine the dependence of the apparent diffusion coefficient and equilibrium swelling of the bilayer as a function of the water vapor activity. To determine transport properties specific to the polyamide layer, sorption kinetics of the bilayer was modeled with a bilayer mass transport model. The swelling and water diffusion coefficients are interpreted according to the Painter-Shenoy polymer network swelling model and the solution-diffusion model, respectively.

  12. 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

  13. Solvent Swelling as a Means to Modify the Properties of Polymer Thin Films

    NASA Astrophysics Data System (ADS)

    Clough, Andrew; Tsui, Ophelia; Chowdhury, Mithun; Jahanshahi, Kaiwan; Reiter, Guenter

    2012-02-01

    It has been observed that sample preparation can influence certain properties of polymer films. In particular, spin-coating from solutions of different solvent qualities result in films with different chain conformations. We surmise that upon formation by spin-coating, the chain conformation of a film is still adjustable by means of solvent swelling, resulting in modifications to the amount of entanglement and free volume. Initial measurements of thermal expansion upon heating after swelling suggest that there is a difference between polystyrene films swelled with a good solvent and a θ solvent. We have begun a more detailed investigation by studying the effect of swelling on the dewetting behaviors. Preliminary data indicates that the quality of the solvent affects both the dewetting hole size and aging rate of the film.

  14. 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.

  15. Soft Tissue Swelling Associated with the Use of Recombinant Human Bone Morphogenetic Protein-2 in Long Bone Non-unions

    PubMed Central

    Young, Andrew; Mirarchi, Adam

    2015-01-01

    Introduction: This report describes two cases of long bone non-union associated with the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) and is the first of its kind. The first case describes a 25-year-old male who sustained a left diaphyseal femoral shaft fracture initially treated with operative fixation using an intramedullary nail, which subsequently loosened distally and was treated with exchange nailing and rhBMP-2 application. This patient developed acute local soft tissue inflammation post-operatively. The second case describes a 61-year-old female who sustained a right diaphyseal humeral shaft fracture that was initially treated with intramedullary nail fixation with subsequent distal interlock screw loosening. She underwent nail removal, and compression plating with rhBMP-2 placement, and postoperatively developed severe acute local tissue swelling centered over the rhBMP-2 sponge. Surgeons should be aware that rhBMP-2 may cause local acute tissue swelling and recombinant bone morphogenic proteins such as rhBMP-2 may have a role in the management for atrophic fracture non-unions. The authors recommend careful consideration prior to rhBMP-2 use in long bone non-unions. PMID:27299059

  16. Stabilization of large drainage basins over geological time scales: Cenozoic West Africa, hot spot swell growth, and the Niger River

    NASA Astrophysics Data System (ADS)

    Chardon, Dominique; Grimaud, Jean-Louis; Rouby, Delphine; Beauvais, Anicet; Christophoul, Frédéric

    2016-03-01

    Reconstructing the evolving geometry of large river catchments over geological time scales is crucial to constraining yields to sedimentary basins. In the case of Africa, it should further help deciphering the response of large cratonic sediment routing systems to Cenozoic growth of the basin-and-swell topography of the continent. Mapping of dated and regionally correlated lateritic paleolandscape remnants complemented by onshore sedimentological archives allows the reconstruction of two physiographic configurations of West Africa in the Paleogene. Those reconstructions show that the geometry of the drainage is stabilized by the late early Oligocene (29 Ma) and probably by the end of the Eocene (34 Ma), allowing to effectively link the inland morphoclimatic record to offshore sedimentation since that time, particularly in the case of the Niger catchment—delta system. Mid-Eocene paleogeography reveals the antiquity of the Senegambia catchment back to at least 45 Ma and suggests that a marginal upwarp forming a continental divide preexisted early Oligocene connection of the Niger and Volta catchments to the Equatorial Atlantic Ocean. Such a drainage rearrangement was primarily enhanced by the topographic growth of the Hoggar hot spot swell and caused a stratigraphic turnover along the Equatorial margin of West Africa.

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

    PubMed

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

    2011-01-01

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

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

    PubMed

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

    2015-04-01

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

  19. Observations of void swelling in selected austenitic alloys during ion irradiation under a rising temperature ramp

    NASA Astrophysics Data System (ADS)

    Mazey, D. J.; Williams, T. M.; Bolster, D. E. J.

    1988-07-01

    Results are given of a TEM study of the void swelling behaviour of CW AISI 321 (En58B), CW FV548 stainless steel and STA Nimonic PE16 alloy during 46 MeV nickel ion irradiation under a near-linear rising temperature ramp. The dose range for the ramp was 0-75 dpa and four temperature ranges were investigated using 50 ° C intervals from 500-550 ° C, 525-575 ° C, 575-625 ° C and 625-675 ° C. Swelling in CW 321 was found to be no greater than that observed after isothermal irradiation to 75 dpa at temperatures corresponding to the end-of-ramp temperatures. This was not the case for CW FV548 where the swelling for the temperature ranges of 525-575 ° C and 575-625 ° C was slightly greater than that observed under isothermal irradiation to 75 dpa. Swelling in STA PE16 in the lower temperature ranges of 500-550 ° C and 525-575°C was much higher than corresponding isothermal values but in the 600-700 ° C temperature range the swelling was close to isothermal values. The results on PE16 indicate that a steady increase in irradiation temperature from just below or just above the low temperature cut-off into the void swelling region produces a significant increase in swelling with respect to that expected under isothermal conditions. Possible interpretations of the observed swelling behaviour in these alloys are discussed.

  20. 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.

  1. 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%.

  2. Effect of cyclosporin A and trifluoperazine on rat liver mitochondria swelling and lipid peroxidation.

    PubMed

    Nepomuceno, M F; Pereira-da-Silva, L

    1993-10-01

    The effect of cyclosporin A (CsA) or trifluoperazine (TFP) on lipid peroxidation and mitochondrial swelling was determined using liver mitochondria incubated with 30 microM Ca2+ and 250 microM t-butylhydroperoxide or 5 mM inorganic phosphate (P(i)). Lipid peroxidation was not modified by either 1 microM CsA or 40 microM TFP. These compounds presented a distinct effect on mitochondrial permeability. Under oxidative conditions, CsA only showed a transient protective effect whereas TFP completely inhibited mitochondrial swelling. Conversely, CsA was very efficient when Ca2+ and P(i) were used, a condition under which TFP was unable to prevent the swelling. These data are consistent with our previous results (M.F. Nepomuceno, D.V. Macedo and L. Pereira-da-Silva (1991). Brazilian Journal of Medical and Biological Research, 24: 833-836) showing that lipid peroxidation is one among other different components of the permeabilization process. The data suggest that lipid peroxidation is independent of swelling, occurring later than swelling, presumably when the mitochondrial reductant systems are depleted. The differential effects of CsA and TFP suggest that these compounds can be used as specific probes in the elucidation of the two distinct mechanisms responsible for mitochondrial swelling.

  3. 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

  4. Swelling and softening of the cowpea chlorotic mottle virus in response to pH shifts.

    PubMed

    Wilts, Bodo D; Schaap, Iwan A T; Schmidt, Christoph F

    2015-05-19

    Cowpea chlorotic mottle virus (CCMV) forms highly elastic icosahedral protein capsids that undergo a characteristic swelling transition when the pH is raised from 5 to 7. Here, we performed nano-indentation experiments using an atomic force microscope to track capsid swelling and measure the shells' Young's modulus at the same time. When we chelated Ca(2+) ions and raised the pH, we observed a gradual swelling of the RNA-filled capsids accompanied by a softening of the shell. Control experiments with empty wild-type virus and a salt-stable mutant revealed that the softening was not strictly coupled to the swelling of the protein shells. Our data suggest that a pH increase and Ca(2+) chelation lead primarily to a loosening of contacts within the protein shell, resulting in a softening of the capsid. This appears to render the shell metastable and make swelling possible when repulsive forces among the capsid proteins become large enough, which is known to be followed by capsid disassembly at even higher pH. Thus, softening and swelling are likely to play a role during inoculation.

  5. Theoretical basis for an anomalous temperature coefficient in swelling pressure of rabbit corneal stroma.

    PubMed Central

    Kwok, L S; Klyce, S D

    1990-01-01

    In the rabbit corneal stroma, the swelling pressure, P, has been reported to have an anomalous (negative) temperature coefficient, alpha P, contradicting traditional Donnan swelling theory. A parallel-plate, diffuse double layer Gouy-Chapman model was used to resolve this discrepancy. The present model incorporates the possibility that surface charge, sigma, is temperature dependent. It is shown that negative, zero, or positive coefficients of swelling pressure change with temperature are not mutually exclusive conditions, but can be attributed to the same underlying mechanism. For likely values of alpha P(range -7 x 10(-3) K-1 to +3.2 x 10(-3)K-1), the effective stromal charge has a negative temperature dependency, or dln sigma/dT less than 0. The present formalism is robust against variation in assumed alpha P, and is able to simultaneously satisfy the known values of swelling pressure, its thermal dependency, and stromal charge. These results implicate significant coulombic forces behind P. Predicted stromal surface charge is approximately 0.01 Cm-2. The predictions were confirmed with macrocontinuum Donnan swelling theory, suggesting that Donnan osmotic swelling is the principal macroscopic component of P. PMID:2306510

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

    PubMed

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

    2015-08-01

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

  7. 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

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

    NASA Astrophysics Data System (ADS)

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

    2008-07-01

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

  9. Does low-level laser therapy decrease swelling and pain resulting from orthognathic surgery?

    PubMed

    Gasperini, G; Rodrigues de Siqueira, I C; Rezende Costa, L

    2014-07-01

    Low-level laser therapy (LLLT) could be an alternative for the treatment of swelling and pain after orthognathic surgery, but there is a paucity of data in the literature on the effects of its use. This study verified the efficacy of an LLLT protocol to reduce swelling and pain after orthognathic surgery. Ten healthy patients who underwent a bilateral sagittal split with Le Fort I osteotomy were randomly selected for this study. The LLLT protocol consisted of intraoral and extraoral application to one side of the face after surgery (irradiated side); application to the other side was simulated (non-irradiated side). The irradiated and non-irradiated sides were compared regarding the swelling coefficient and were assessed for pain using a visual analogue scale. There were no significant differences between the irradiated and non-irradiated sides regarding swelling and pain in the immediate postoperative assessment. Swelling decreased significantly on the irradiated side in the postoperative assessments on days 3, 7, 15, and 30. Self-reported pain was less intense on the irradiated side at the 24-h (1.2 vs. 3.4) and 3-day (0.6 vs. 2.1) assessments, but at 7 days after surgery neither side showed pain. This LLLT protocol can improve the tissue response and reduce the pain and swelling resulting from orthognathic surgery.

  10. 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

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

    PubMed

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

    2009-06-01

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

  12. Study of equilibrium properties of Cr(III)/polyacrylamide gels by swelling measurement and equilibrium dialysis

    SciTech Connect

    Young, T.S.; Hunt, J.A.; Green, D.W.; Willhite, G.P. )

    1989-08-01

    In observations of the long-term properties of a series of Cr(III)/polyacrylamide (PAAM) gels, the gels either underwent syneresis upon aging or swelled in contact with excess brine. Both syneresis and swelling can substantially change the volume and properties of a gel placed in a formation and therefore influence the effectiveness of a crosslinked-polymer treatment. Efforts were made to develop an understanding of these phenomena and to describe them in terms of the gel's physical and chemical states. A long-term gel's physical and chemical states are characterized by two parameters, effective crosslinking density and chromium density, determined by equilibrium swelling and equilibrium dialysis, respectively. Swelling and syneresis properties were correlated to the effective cross-linking density described in polymer network theory. A model based on Flory and Hermans' swelling equations was developed to calculate the effective crosslinking densities of gels prepared from solution. Attempts were made to relate the swelling and syneresis properties to the compositions of gel systems to allow prediction of long-term stability of a gel based on its composition. An analysis of the amount of chromium that reacted with the PAAM was made by successive equilibrium dialyses of the gel followed by chromium analyses of dialysates by atomic and visible absorptions.

  13. Influence of Water Content on the Mechanical Properties of an Argillaceous Swelling Rock

    NASA Astrophysics Data System (ADS)

    Vergara, Maximiliano R.; Triantafyllidis, Theodoros

    2016-07-01

    This work presents the results of an experimental investigation aimed to study the effect of water on the mechanical properties of a partially saturated argillaceous swelling rock. The mineralogical composition of the rock, in particular the portion of swelling clays, was determined with X-ray diffraction. The water retention curve was estimated using a dew-point potential meter and the swelling behavior of the studied rock was examined by unconfined and oedometric swelling tests. The influence of water on the rock mechanical properties was assessed by means of triaxial tests. The experimental results indicate a strong decrease of strength and stiffness with increasing saturation or decreasing suction. This occurs only within a certain range of saturation. Degradation of the rock properties can be expected for small increments in the water content within this range. At low suction and close to the air-entry value, the stiffness remained constant. As the rock desaturates, the strength and stiffness increase approaching constant values. For suction greater than about 76 MPa, low increase of strength and stiffness was observed. The specimens in the swelling tests reached a saturation degree of 70 % which corresponds to a decrease of strength and stiffness of approximately 80 %. Rock swelling occurring simultaneously with reduction of strength and stiffness, increases deformations and it is an important issue for the stability of excavations.

  14. [A very slow growing ankle swelling in a healthy male].

    PubMed

    Merlo, Christoph; Merlo, Pierina; Holzinger, Fernando; Pranghofer, Sigrid; Pfeiffer, David; Nüesch, Reto

    2014-08-20

    We describe the case report of a 66-year-old man with a very slow growing ankle tumour caused by a subcutaneous fungal abscess. Phaeoacremonium inflatipes, a member of the Dematiaceae family, was identified by needle puncture and culture of the non-odorous creamy yellow brown fluid. The fungal pseudocyst was surgically removed in toto and no further fungicidal drug therapy was required. Human infections by dematiaceous fungi causes subcutaneous phaeohyphomycosis, a rare, deep fungal infection of the skin and subcutaneous tissues usually acquired through traumatic skin lesions. In addition, systemic infections are reported, predominantly in immunosuppressed individuals.

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

    PubMed

    Li, Jingdong; Wu, Xiangqiong; Cui, Tianpen

    2008-02-01

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

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

    PubMed Central

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

    2014-01-01

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

  17. Modeling the controllable pH-responsive swelling and pore size of networked alginate based biomaterials.

    PubMed

    Chan, Ariel W; Neufeld, Ronald J

    2009-10-01

    Semisynthetic network alginate polymer (SNAP), synthesized by acetalization of linear alginate with di-aldehyde, is a pH-responsive tetrafunctionally linked 3D gel network, and has potential application in oral delivery of protein therapeutics and active biologicals, and as tissue bioscaffold for regenerative medicine. A constitutive polyelectrolyte gel model based on non-Gaussian polymer elasticity, Flory-Huggins liquid lattice theory, and non-ideal Donnan membrane equilibria was derived, to describe SNAP gel swelling in dilute and ionic solutions containing uni-univalent, uni-bivalent, bi-univalent or bi-bi-valent electrolyte solutions. Flory-Huggins interaction parameters as a function of ionic strength and characteristic ratio of alginates of various molecular weights were determined experimentally to numerically predict SNAP hydrogel swelling. SNAP hydrogel swells pronouncedly to 1000 times in dilute solution, compared to its compact polymer volume, while behaving as a neutral polymer with limited swelling in high ionic strength or low pH solutions. The derived model accurately describes the pH-responsive swelling of SNAP hydrogel in acid and alkaline solutions of wide range of ionic strength. The pore sizes of the synthesized SNAP hydrogels of various crosslink densities were estimated from the derived model to be in the range of 30-450 nm which were comparable to that measured by thermoporometry, and diffusion of bovine serum albumin. The derived equilibrium swelling model can characterize hydrogel structure such as molecular weight between crosslinks and crosslinking density, or can be used as predictive model for swelling, pore size and mechanical properties if gel structural information is known, and can potentially be applied to other point-link network polyelectrolytes such as hyaluronic acid gel.

  18. First report of external ophthalmomyiasis caused by Lucilia sericata Meigen in a healthy patient without predisposing risk factors.

    PubMed

    Choi, Won; Kim, Ga Eon; Park, Seong Hwan; Shin, Sang Eon; Park, Ji Hye; Yoon, Kyung Chul

    2015-10-01

    A 72-year-old man with no medical history initially presented to the emergency room with severe tearing, redness, foreign body sensation, and pain in the left eye. He reported no previous history of any periocular trauma, malignancy, surgery, or systemic illness. On presentation, the patient only showed left periorbital edema and erythema in the left eyelid with no evidence of any skin malignancy. On slit lamp examination, multiple small whitish motile organisms were observed on the left conjunctival fornices. The organisms were removed, preserved, and identified as the third-stage larvae of Lucilia sericata (green bottle fly). The patient was treated with topical antibiotic and steroid eye drops and the inflammation resolved 1 week after treatment initiation. This is the first report of external ophthalmomyiasis caused by facultative parasite, L. sericata maggots in a healthy patient without any predisposing factors.

  19. Evidence and dating of mid-Cretaceous tectonic activity in the San Rafael Swell, Emery County, Utah

    SciTech Connect

    Eaton, J.G. ); Kirkland, J.I. ); Kauffman, E.G. )

    1990-04-01

    Evidence of tectonic activity in the form of recycled conglomerates has been found in middle Cretaceous deposits on the western flank of the San Rafael Swell. These conglomerates, present in the upper part of the Dakota Formation and in the overlying basal Mancos Shale (Tununk Member), are separated by an earliest Turonian unconformity. The conglomerates appear to be derived from the Lower Cretaceous Buckhorn Conglomerate, or similar conglomerates, which were re-exposed by latest Cenomanian uplift. Coarse clastics provided to the nearshore facies of the Dakota Formation by coastal rivers are preserved as a coarsening upward sequence. Continued uplift eventually caused a local marine regression by temporarily inhibiting the initial (latest Cenomanian) transgression of the Greenhorn Sea. In subaerially exposed environments pebbles and cobbles from the Buckhorn were distributed across the coastal floodplain by rivers. These clasts were reworked into a basal lag deposit when renewed transgression of the Greenhorn Sea occurred during the late early Turonian.

  20. Swelling behavior of ion exchange resins incorporated in tri-calcium silicate cement matrix: I. Chemical analysis

    NASA Astrophysics Data System (ADS)

    Neji, M.; Bary, B.; Le Bescop, P.; Burlion, N.

    2015-12-01

    This paper presents the first part of a theoretical and experimental work aiming at modeling the chemo-mechanical behavior of composites made up of ion exchange resins (IER) solidified in a tri-calcium silicate cement paste (C3S). Because of ion exchange processes, the volume change of the IER may cause internal pressures leading to the degradation of the material. In this study, a predictive modeling is developed for describing the chemical behavior of such material. It is based on thermodynamic equilibria to determine the evolution of the ion exchange processes, and the potential precipitation of portlandite in the composite. In parallel, a phenomenological study has been set up to understand chemical phenomena related to the swelling mechanisms. The model created has been finally implemented in a finite elements software; the simulation of a laboratory test has been performed and the results compared to experimental data.

  1. Clay composition and swelling potential estimation of soils using depth of absorption bands in the SWIR (1100-2500 nm) spectral domain

    NASA Astrophysics Data System (ADS)

    Dufréchou, Grégory; Granjean, Gilles; Bourguignon, Anne

    2014-05-01

    Swelling soils contain clay minerals that change volume with water content and cause extensive and expensive damage on infrastructures. Presence of clay minerals is traditionally a good estimator of soils swelling and shrinking behavior. Montmorillonite (i.e. smectite group), illite, kaolinite are the most common minerals in soils and are usually associated to high, moderate, and low swelling potential when they are present in significant amount. Characterization of swelling potential and identification of clay minerals of soils using conventional analysis are slow, expensive, and does not permit integrated measurements. SWIR (1100-2500 nm) spectral domain are characterized by significant spectral absorption bands related to clay content that can be used to recognize main clay minerals. Hyperspectral laboratory using an ASD Fieldspec Pro spectrometer provides thus a rapid and less expensive field surface sensing that permits to measure soil spectral properties. This study presents a new laboratory reflectance spectroscopy method that used depth of clay diagnostic absorption bands (1400 nm, 1900 nm, and 2200 nm) to compare natural soils to synthetic montmorillonite-illite-kaolinite mixtures. We observe in mixtures that illite, montmorillonite, and kaolinite content respectively strongly influence the depth of absorption bands at 1400 nm (D1400), 1900 nm (D1900), and 2200 nm (D2200). To attenuate or removed effects of abundance and grain size, depth of absorption bands ratios were thus used to performed (i) 3D (using D1900/D2200, D1400/D1900, and D2200/D1400 as axis), and (ii) 2D (using D1400/D1900 and D1900/D2200 as axis) diagrams of synthetic mixtures. In this case we supposed that the overall reduction or growth of depth absorption bands should be similarly affected by the abundance and grain size of materials in soil. In 3D and 2D diagrams, the mixtures define a triangular shape formed by two clay minerals as external envelop and the three clay minerals mixtures

  2. Swelling-activated Ca2+ entry via TRPV4 channel is defective in cystic fibrosis airway epithelia.

    PubMed

    Arniges, Maite; Vázquez, Esther; Fernández-Fernández, José M; Valverde, Miguel A

    2004-12-24

    The vertebrate transient receptor potential cationic channel TRPV4 has been proposed as an osmo- and mechanosensor channel. Studies using knock-out animal models have further emphasized the relevance of the TRPV4 channel in the maintenance of the internal osmotic equilibrium and mechanosensation. However, at the cellular level, there is still one important question to answer: does the TRPV4 channel generate the Ca(2+) signal in those cells undergoing a Ca(2+)-dependent regulatory volume decrease (RVD) response? RVD in human airway epithelia requires the generation of a Ca(2+) signal to activate Ca(2+)-dependent K(+) channels. The RVD response is lost in airway epithelia affected with cystic fibrosis (CF), a disease caused by mutations in the cystic fibrosis transmembrane conductance regulator channel. We have previously shown that the defective RVD in CF epithelia is linked to the lack of swelling-dependent activation of Ca(2+)-dependent K(+) channels. In the present study, we show the expression of TRPV4 in normal human airway epithelia, where it functions as the Ca(2+) entry pathway that triggers the RVD response after hypotonic stress, as demonstrated by TRPV4 antisense experiments. However, cell swelling failed to trigger Ca(2+) entry via TRPV4 channels in CF airway epithelia, although the channel's response to a specific synthetic activator, 4 alpha-phorbol 12,13-didecanoate, was maintained. Furthermore, RVD was recovered in CF airway epithelia treated with 4 alpha-phorbol 12,13-didecanoate. Together, these results suggest that defective RVD in CF airway epithelia might be caused by the absence of a TRPV4-mediated Ca(2+) signal and the subsequent activation of Ca(2+)-dependent K(+) channels. PMID:15489228

  3. An upscaling method and a numerical analysis of swelling/shrinking processes in a compacted bentonite/sand mixture

    NASA Astrophysics Data System (ADS)

    Xie, M.; Agus, S. S.; Schanz, T.; Kolditz, O.

    2004-12-01

    This paper presents an upscaling concept of swelling/shrinking processes of a compacted bentonite/sand mixture, which also applies to swelling of porous media in general. A constitutive approach for highly compacted bentonite/sand mixture is developed accordingly. The concept is based on the diffuse double layer theory and connects microstructural properties of the bentonite as well as chemical properties of the pore fluid with swelling potential. Main factors influencing the swelling potential of bentonite, i.e. variation of water content, dry density, chemical composition of pore fluid, as well as the microstructures and the amount of swelling minerals are taken into account. According to the proposed model, porosity is divided into interparticle and interlayer porosity. Swelling is the potential of interlayer porosity increase, which reveals itself as volume change in the case of free expansion, or turns to be swelling pressure in the case of constrained swelling. The constitutive equations for swelling/shrinking are implemented in the software GeoSys/RockFlow as a new chemo-hydro-mechanical model, which is able to simulate isothermal multiphase flow in bentonite. Details of the mathematical and numerical multiphase flow formulations, as well as the code implementation are described. The proposed model is verified using experimental data of tests on a highly compacted bentonite/sand mixture. Comparison of the 1D modelling results with the experimental data evidences the capability of the proposed model to satisfactorily predict free swelling of the material under investigation. Copyright

  4. Prediction of swelling of 18Cr10NiTi austenitic steel over a wide range of displacement rates

    NASA Astrophysics Data System (ADS)

    Kalchenko, A. S.; Bryk, V. V.; Lazarev, N. P.; Neklyudov, I. M.; Voyevodin, V. N.; Garner, F. A.

    2010-04-01

    The internal components of pressurized water reactors of Russian types WWER-440 and WWER-1000 are constructed of annealed 18Cr10NiTi steel, a close analog to AISI 321. Void swelling of the internals is a concern for plant life extension and predictive equations are required to assess the potential of swelling in critical components such as the baffle ring or reflection shield that surrounds the WWER core. The only previously available swelling data for this steel were derived at higher than PWR-relevant displacement rates in the BOR-60 fast reactor. The swelling equation previously developed from these data does not incorporate the effect of displacement rate on swelling. Using heavy-ion irradiation at very high dpa rates (10 -2 and 10 -3 dpa s -1) and doses (5-100 dpa) and coupling the results to available neutron data a swelling equation has been developed that specifically incorporates the effect of dpa rate on void swelling. Experimental results allow description of the swelling peak, the incubation period and the steady-state swelling rate over a wide range of irradiation temperature. For the first time it appears possible to describe both ion and neutron data on this steel within the framework of a single empirical model. Swelling maps constructed from this model permit forecasting of the behavior of the steel in WWERs under the required irradiation conditions, not only at already attained exposure doses, but more importantly to higher dose levels that will be reached following plant life extension.

  5. Prediction of void swelling in the baffle ring of WWER-1000 reactors for service life of 30-60 years

    NASA Astrophysics Data System (ADS)

    Kalchenko, A. S.; Bryk, V. V.; Lazarev, N. P.; Voyevodin, V. N.; Garner, F. A.

    2013-06-01

    Major internal components of WWER-type nuclear reactors are made from annealed 18Cr10NiTi steel, a close analog to AISI 321. Void swelling of the baffle ring in particular could be a major factor limiting operation of the reactor beyond the current 30 years license. A predictive swelling equation is needed to forecast the spatial variation of swelling so as to identify those areas requiring additional attention. Available data on the swelling of this steel arising from irradiation in the BOR-60 fast reactor was combined with data from a heavy ion accelerator at higher displacement rates to formulate a predictive equation of swelling for the WWER-relevant range of temperature, irradiation dose and dose rates. This equation was used to estimate the swelling distribution over a cross-section of the baffle ring of a WWER reactor during a service life up to 60 years, reaching a local maximum of ˜30% swelling. It was shown that void swelling extends over a larger portion of the baffle ring than previously expected and exhibits a very complex and irregular distribution in response to complex distributions of temperature and dpa rate. Most importantly, as operation is extended beyond 30 years several areas of the ring may experience swelling in excess of 10% where void-induced embrittlement begins and one area may exceed 20% after 45 years, a swelling level where a complete loss of ductility is known to occur.

  6. Numerical Simulation of Injectivity Effects of Mineral Scaling and Clay Swelling in a Fractured Geothermal Reservoir

    SciTech Connect

    Xu, Tianfu; Pruess, Karsten

    2004-05-10

    A major concern in the development of hot dry rock (HDR) and hot fractured rock (HFR) reservoirs is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths such as those caused by thermally-induced stress cracking. Past analyses of HDR and HFR reservoirs have tended to focus primarily on the coupling between hydrology (flow), heat transfer, and rock mechanics. Recent studies suggest that rock-fluid interactions and associated mineral dissolution and precipitation effects could have a major impact on the long-term performance of HFR reservoirs. The present paper uses recent European studies as a starting point to explore chemically-induced effects of fluid circulation in HFR systems. We examine ways in which the chemical composition of reinjected waters can be modified to improve reservoir performance by maintaining or even enhancing injectivity. Chemical manipulations considered here include pH modification and dilution with fresh water. We performed coupled thermo-hydrologic-chemical simulations in which the fractured medium was represented by a one-dimensional MINC model (multiple interacting continua), using the non-isothermal multi-phase reactive geochemical transport code TOUGHREACT. Results indicate that modifying the injection water chemistry can enhance mineral dissolution and reduce clay swelling. Chemical interactions between rocks and fluids will change a HFR reservoir over time, with some changes favorable and others not. A detailed, quantitative understanding of processes and mechanisms can suggest chemical methods for reservoir management, which may be employed to improve the performance of the geothermal system.

  7. Elevation trends and shrink-swell response of wetland soils to flooding and drying

    USGS Publications Warehouse

    Cahoon, Donald R.; Perez, Brian C.; Segura, Bradley D.; Lynch, James C.

    2011-01-01

    Given the potential for a projected acceleration in sea-level rise to impact wetland sustainability over the next century, a better understanding is needed of climate-related drivers that influence the processes controlling wetland elevation. Changes in local hydrology and groundwater conditions can cause short-term perturbations to marsh elevation trends through shrink—swell of marsh soils. To better understand the magnitude of these perturbations and their impacts on marsh elevation trends, we measured vertical accretion and elevation dynamics in microtidal marshes in Texas and Louisiana during and after the extreme drought conditions that existed there from 1998 to 2000. In a Louisiana marsh, elevation was controlled by subsurface hydrologic fluxes occurring below the root zone but above the 4 m depth (i.e., the base of the surface elevation table benchmark) that were related to regional drought and local meteorological conditions, with marsh elevation tracking water level variations closely. In Texas, a rapid decline in marsh elevation was related to severe drought conditions, which lowered local groundwater levels. Unfragmented marshes experienced smaller water level drawdowns and more rapid marsh elevation recovery than fragmented marshes. It appears that extended drawdowns lead to increased substrate consolidation making it less resilient to respond to future favorable conditions. Overall, changes in water storage lead to rapid and large short-term impacts on marsh elevation that are as much as five times greater than the long-term elevation trend, indicating the importance of long-term, high-resolution elevation data sets to understand the prolonged effects of water deficits on marsh elevation change.

  8. Gas swelling and deuterium distribution in beryllium implanted with deuterium ions

    SciTech Connect

    Chernikov, V.N.; Alimov, V.Kh.; Zakharov, A.P.

    1995-09-01

    An extensive TEM study of the microstructure of Be TIP-30 irradiated with 3 and 10 keV D ions up to fluences, {Phi}, in the range from 3 x 10{sup 20} to 8 x 10{sup 21} D/m{sup 2} at temperatures T{sub irr} = 300 K, 500 K and 700 K has been carried out. Depth distributions of deuterium in the form of separate D atoms and D{sub 2} molecules have been investigated by means of SIMS and RGA methods, correspondingly. D ion irradiation is accompanied by blistering and gives rise to different kind of destructions depending mainly on the irradiation temperature. Irradiation with D ions at 300 K leads to the formation of tiny highly pressurized D{sub 2} bubbles reminiscent of He bubbles in Be. Under 3 keV D ion irradiation D{sub 2} bubbles ({bar r}{sub b} {approx} 0.7 nm) appear at a fluence as low as 3x10{sup 20} D/m{sup 2}. Irradiation at 500 K results in the development, along with relatively small facetted bubbles, of larger oblate gas-filled cavities accumulating most of injected D atoms and providing for much higher gas swelling values as compared to irradiation at 300 K. The increase of D and/or T{sub irr}, to 700 K causes the further coarsening of large cavities which are transformed into sub-surface labyrinth structures. D and He ion implantation leads to the enhanced growth of porous microcrystalline layers of c.p.h.-BeO oxide with a microstructure which differs considerably from that of oxide layers on electropolished surfaces of Be. Based on the analysis of experimental data questions of deuterium reemission, thermal desorption and trapping in Be have been discussed in detail.

  9. Molecular accessibility in solvent swelled coals. Quarterly report, [April--June 1993

    SciTech Connect

    Kispert, L.D.

    1993-08-01

    The effect of weathering (oxidation and dehydration upon exposure to air) on the molecular accessibility of potential catalysts was studied by the EPR spin probe technique. Fresh samples of all 8 APCS coals were exposed to air for periods up to 36 days. Weathering produced significant effects on the retention of spin probes in most of the APCS coals under 91 % carbon (dmmf). It was determined that the lower ranked coal (Beulah Zap and Wyodak) under went a structural collapse which precluded retention of even spin probe VIII. However, medium ranked coals exhibited improved retention upon weathering when swelled in toluene. Swelling with pyridine opened up small pores for 81--86% carbon which is not observed for swelling with toluene. Changes in coal structure were successfully followed by the EPR spin probe method. A detailed analysis of the data collected from the swelling of coals oxidized in a moisture free environment was completed to differentiate between weathering and oxidation. Eight vacuum dried APCS coals were oxidized in an enclosed, pure oxygen, moisture free environment, and the effects of oxidation alone on coal structure were studied by the intercalation of EPR spin probes. The data shows a factor of 5 increase in spin probe retention for some coals oxidized in O{sub 2} versus air., suggesting a large increase in oxidized material. Particular care was taken during the swelling procedures to avoid exposure of the coal samples to air or moisture. EPR spectra were then obtained for these 300 samples.

  10. 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. PMID:24702940

  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. Void swelling of an oxide dispersion strengthened ferritic alloy in a high voltage electron microscope

    NASA Astrophysics Data System (ADS)

    Snykers, M.

    1980-03-01

    An oxide dispersion strengthened ferritic alloy with nominal composition Fe-13Cr-3.5Ti-1.5Mo-2TiO 2 and a cast alloy with a composition close to that of the matrix of the oxide dispersion strengthened alloy are irradiated in a high voltage electron microscope in the temperature range 380-550°C. The alloys are doped with 0-30 ppm helium. For alloys containing 10 ppm He a peak swelling temperature at 450°C is found. A maximum swelling of 1.1% is found at an irradiation dose of 20 dpa. In the absence of He no swelling is found in the temperature range 430-470°C. The swelling rate is highest at the onset of swelling. The results obtained here are quite similar to those for some ferritic steels such as FV607, EM 12 and HT9, except for the influence of He and for the dose dependence.

  13. 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

  14. 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

  15. Inhibitors of swelling-activated chloride channels increase infarct size and apoptosis in rabbit myocardium.

    PubMed

    Souktani, Rachid; Ghaleh, Bijan; Tissier, Renaud; d'Anglemont de Tassigny, Alexandra; Aouam, Karim; Bedossa, Pierre; Charlemagne, Danièle; Samuel, Janelyse; Henry, Patrick; Berdeaux, Alain

    2003-10-01

    Apoptosis is a significant contributor to myocardial cell death during ischemia-reperfusion and swelling-activated chloride channels (I(Cl,swell)) contribute to apoptosis. However, the relationship between I(Cl,swell) ischemia-reperfusion and apoptosis remains unknown. To further investigate this, New Zealand rabbits underwent a 20-min coronary artery occlusion (CAO) followed by 72 h of coronary artery reperfusion (CAR). Two I(Cl,swell) blockers, 5-nitro-2-[3-phenylpropylamino]benzoic acid (NPPB) and indanyloxyacetic acid 94 (IAA-94) (both 1 mg/kg), were administered prior to CAO and throughout the 72 h CAR. Infarct size (IS) was increased with NPPB and IAA-94 compared with control (vehicle) rabbits (51 +/- 2% and 48 +/- 3% and vs. 35 +/- 2%, respectively, P < 0.05). Similar results were found when NPPB was administered only during the reperfusion period. The percentage of TUNEL-positive nuclei in the border zone of the infarct was increased with NPPB compared with control (37 +/- 2% vs. 25 +/- 31%, P < 0.05) as well as the number of cytoplasmic histone-associated DNA fragments (0.45 +/- 0.06 vs. 0.33 +/- 0.04 absorbance units, P < 0.05). These findings support the concept that I(Cl,swell) channels play an important role in the determination of myocardial infarct size and apoptosis during ischemia-reperfusion. PMID:14703716

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

    PubMed

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

    2000-07-01

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

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

    PubMed

    Hübel, Niklas; Ullah, Ghanim

    2016-01-01

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

  18. Starch-free grewia gum matrices: Compaction, swelling, erosion and drug release behaviour.

    PubMed

    Nep, E I; Asare-Addo, K; Ghori, M U; Conway, B R; Smith, A M

    2015-12-30

    Polysaccharides are suitable for application as hydrophilic matrices because of their ability to hydrate and swell upon contact with fluids, forming a gel layer which controls drug release. When extracted from plants, polysaccharides often contain significant quantities of starch that impacts upon their functional properties. This study aimed to evaluate differences in swelling, erosion and drug release from matrix tablets prepared from grewia gum (GG) and starch-free grewia gum (GDS) extracted from the stems of Grewia mollis. HPMC was used as a control polymer with theophylline as a model drug. Swelling, erosion, and in-vitro release were performed in deionized water, pH 1.2 and pH 6.8 media. The Vergnaud and Krosmeyer-Peppas model were used for swelling and drug release kinetics, respectively. However, linear regression technique was used to determine the erosion rate. GDS compacts were significantly harder than the native GG and HPMC compacts. GDS matrices exhibited the fastest erosion and drug release in deionised water and phosphate buffer compared with the GG and HPMC. At pH 1.2, GDS exhibited greater swelling than erosion, and drug release was similar to GG and HPMC. This highlights the potential of GDS as a matrix for controlled release similar to HPMC and GG at pH 1.2 but with a more rapid release at pH 6.8. GDS may have wider application in reinforcing compacts with relatively low mechanical strength.

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

    PubMed

    Hübel, Niklas; Ullah, Ghanim

    2016-01-01

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

  20. 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

  1. 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.

  2. Exercise-Induced Changes in Caveolin-1, Depletion of Mitochondrial Cholesterol, and the Inhibition of Mitochondrial Swelling in Rat Skeletal Muscle but Not in the Liver.

    PubMed

    Flis, Damian Jozef; Olek, Robert Antoni; Kaczor, Jan Jacek; Rodziewicz, Ewa; Halon, Malgorzata; Antosiewicz, Jedrzej; Wozniak, Michal; Gabbianelli, Rosita; Ziolkowski, Wieslaw

    2016-01-01

    The reduction in cholesterol in mitochondria, observed after exercise, is related to the inhibition of mitochondrial swelling. Caveolin-1 (Cav-1) plays an essential role in the regulation of cellular cholesterol metabolism and is required by various signalling pathways. Therefore, the aim of this study was to investigate the effect of prolonged swimming on the mitochondrial Cav-1 concentration; additionally, we identified the results of these changes as they relate to the induction of changes in the mitochondrial swelling and cholesterol in rat skeletal muscle and liver. Male Wistar rats were divided into a sedentary control group and an exercise group. The exercised rats swam for 3 hours and were burdened with an additional 3% of their body weight. After the cessation of exercise, their quadriceps femoris muscles and livers were immediately removed for experimentation. The exercise protocol caused an increase in the Cav-1 concentration in crude muscle mitochondria; this was related to a reduction in the cholesterol level and an inhibition of mitochondrial swelling. There were no changes in rat livers, with the exception of increased markers of oxidative stress in mitochondria. These data indicate the possible role of Cav-1 in the adaptive change in the rat muscle mitochondria following exercise. PMID:26839631

  3. Roles of basolateral solute uptake via NKCC1 and of myosin II in vasopressin-induced cell swelling in inner medullary collecting duct.

    PubMed

    Chou, Chung-Lin; Yu, Ming-Jiun; Kassai, Eliza M; Morris, Ryan G; Hoffert, Jason D; Wall, Susan M; Knepper, Mark A

    2008-07-01

    Collecting duct cells swell when exposed to arginine vasopressin (AVP) in the presence of a transepithelial osmolality gradient. We investigated the mechanisms of AVP-induced cell swelling in isolated, perfused rat inner medullary collecting ducts (IMCDs) using quantitative video microscopy and fluorescence-based measurements of transepithelial water transport. We tested the roles of transepithelial water flow, basolateral solute entry, and the cytoskeleton (actomyosin). When a transepithelial osmolality gradient was imposed by addition of NaCl to the bath, AVP significantly increased both water flux and cell height. When the osmolality gradient was imposed by addition of mannitol, AVP increased water flux but not cell height, suggesting that AVP-induced cell swelling requires a NaCl gradient and is not merely dependent on the associated water flux. Bumetanide (Na-K-2Cl cotransporter inhibitor) added to the bath markedly diminished the AVP-induced cell height increase. AVP-induced cell swelling was absent in IMCDs from NKCC1-knockout mice. In rat IMCDs, replacement of Na, K, or Cl in the peritubular bath caused significant cell shrinkage, consistent with a basolateral solute transport pathway dependent on all three ions. Immunocytochemistry using an antibody to NKCC1 confirmed basolateral expression in IMCD cells. The conventional nonmuscle myosin II inhibitor blebbistatin also diminished the AVP-induced cell height increase and cell shape change, consistent with a role for the actin cytoskeleton and myosin II. We conclude that the AVP-induced cell height increase is dependent on basolateral solute uptake via NKCC1 and changes in actin organization via myosin II, but is not dependent specifically on increased apical water entry.

  4. Real-time observation of the swelling and hydrolysis of a single crystalline cellulose fiber catalyzed by cellulase 7B from Trichoderma reesei.

    PubMed

    Wang, Jingpeng; Quirk, Amanda; Lipkowski, Jacek; Dutcher, John R; Hill, Christopher; Mark, Adam; Clarke, Anthony J

    2012-06-26

    The biodegradation of cellulose involves the enzymatic action of cellulases (endoglucanases), cellobiohydrolases (exoglucanases), and β-glucosidases that act synergistically. The rate and efficiency of enzymatic hydrolysis of crystalline cellulose in vitro decline markedly with time, limiting the large-scale, cost-effective production of cellulosic biofuels. Several factors have been suggested to contribute to this phenomenon, but there is considerable disagreement regarding the relative importance of each. These earlier investigations were hampered by the inability to observe the disruption of crystalline cellulose and its subsequent hydrolysis directly. Here, we show the application of high-resolution atomic force microscopy to observe the swelling of a single crystalline cellulose fiber and its-hydrolysis in real time directly as catalyzed by a single cellulase, the industrially important cellulase 7B from Trichoderma reesei. Volume changes, the root-mean-square roughness, and rates of hydrolysis of the surfaces of single fibers were determined directly from the images acquired over time. Hydrolysis dominated the early stage of the experiment, and swelling dominated the later stage. The high-resolution images revealed that the combined action of initial hydrolysis followed by swelling exposed individual microfibrils and bundles of microfibrils, resulting in the loosening of the fiber structure and the exposure of microfibrils at the fiber surface. Both the hydrolysis and swelling were catalyzed by the native cellulase; under the same conditions, its isolated carbohydrate-binding module did not cause changes to crystalline cellulose. We anticipate that the application of our AFM-based analysis on other cellulolytic enzymes, alone and in combination, will provide significant insight into the process of cellulose biodegradation and greatly facilitate its application for the efficient and economical production of cellulosic ethanol.

  5. Gold nanorods as nanotransducers to monitor the growth and swelling of ultrathin polymer films.

    PubMed

    Tian, Limei; Fei, Max; Kattumenu, Ramesh; Abbas, Abdennour; Singamaneni, Srikanth

    2012-06-29

    In this work, we demonstrate that plasmonic nanostructures can be employed as nanoscale transducers to monitor the growth and phase transitions in ultrathin polymer films. In particular, gold nanorods with high refractive index sensitivity (~150 nm/refractive index unit (RIU)) were employed to probe the growth and swelling of polyelectrolyte multilayers (PEM). By comparing the wavelength shift and extinction intensity increase of the localized surface plasmon resonance (LSPR) of the gold nanorods coated with PEM in air and water, the swelling of PEM was estimated to be 26% ± 6%. The swelling was quantitatively confirmed with independent thickness measurement of PEM in dry and swollen states using AFM. The deployment of shape-controlled metal nanostructures with high refractive index sensitivity represents a novel and facile approach for monitoring the phase transition in polymers with nanoscale resolution.

  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. 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.

  8. Erythrocyte swelling and membrane hole formation in hypotonic media as studied by conductometry.

    PubMed

    Pribush, A; Meyerstein, D; Hatskelzon, L; Kozlov, V; Levi, I; Meyerstein, N

    2013-02-01

    Hypoosmotic swelling of erythrocytes and the formation of membrane holes were studied by measuring the dc conductance (G). In accordance with the theoretical predictions, these processes are manifested by a decrease in G followed by its increase. Thus, unlike the conventional osmotic fragility test, the proposed methodological approach allows investigations of both the kinetics of swelling and the erythrocyte fragility. It is shown that the initial rate of swelling and the equilibrium size of the cells are affected by the tonicity of a hypotonic solution and the membrane rheological properties. Because the rupture of biological membranes is a stochastic process, a time-dependent increase in the conductance follows an integral distribution function of the membrane lifetime. The main conclusion which stems from reported results is that information about rheological properties of red blood cell (RBC) membranes and the resistivity of RBCs to a certain osmotic shock may be extracted from conductance signals. PMID:23343529

  9. Moisture induced softening and swelling of natural cellulose fibres in composite applications

    NASA Astrophysics Data System (ADS)

    Gamstedt, E. K.

    2016-07-01

    Composites based on natural cellulose fibres are susceptible to moisture. The fibres as well as the composite will inevitably soften and swell as moisture is absorbed. The intention of the present paper is to shed some light on the mechanisms behind softening and swelling. Also references to modelling work are made, to predict the moisture-induced dimensional stability. Characterisation techniques and models of such kind can be useful in choosing suitable fibres for improved moisture resistance, and identifying the main controlling parameters which affect the engineering consequences of moisture absorption. Understanding of the mechanisms and the main contributions to swelling can rationalise materials development. The examples shown in this review attempt to show the benefits by experimental mechanics and modelling in development of moisture resistant cellulose composites.

  10. 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

  11. An ambiguous asymptomatic swelling in the maxillary anterior region—A case report

    PubMed Central

    Surej Kumar, L.K.; Manuel, Suvy; Nair, Bindu J.; Nair S, Vinod

    2016-01-01

    Introduction Glandular odontogenic cyst is a rare and recently recognized type of developmental odontogenic cyst. Being odontogenic in origin, because of the pluripotentiality of the odontogenic epithelium it can show glandular or salivary features. Presentation of a case A 46 year old female patient was referred to the Oral and Maxillofacial Surgery department with chief complaint of painless swelling in the right anterior region of maxilla, radiographically associated with teeth 12, 13. Mucosa over the swelling was slightly bluish in colour and no associated palatal swelling was seen. No incidence of trauma was reported and involved teeth were not mobile. Discussion Although we have many differential diagnoses, our working diagnosis was a periapical cyst, so conventional treatment of root canal treatment, cyst enucleation, and apicoectomy was planned. Conclusion Here we present a case which was initially misdiagnosed and mismanaged but on subsequent histopathologic examination revealed the final diagnosis. PMID:27093689

  12. 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.

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

    PubMed

    Oni, Y; Soboyejo, W O

    2012-01-01

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

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  16. Decreased swelling pressure of rat nucleus pulposus associated with simulated weightlessness

    NASA Technical Reports Server (NTRS)

    Hargens, Alan R.; Mahmood, Mubashar

    1989-01-01

    Data are presented on the effects of actual and simulated weightlessness on the swelling pressure of nucleus pulposus in rats exposed to 12.5 days of flight aboard Cosmos 1887 or to seven days of tail suspension, respectively. The flight-exposed rats were adapted to normal gravity for over 50 hrs prior to sacrifice and tissue harvesting. In the experiments with flight-exposed rats, swelling pressures were 690, 675, and 622 mm Hg for flight rats, synchronous controls, and vivarium controls, respectively. In experiments with simulated weightlessness, swelling pressures were 295, 610, and 527 mm Hg for tail-suspended rats, cage controls, and vivarium controls, respectively, suggesting that fluid moves into the disc during seven days of simulated weightlessness.

  17. 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.

  18. Investigation of the swelling behaviour of hydrogels in aqueous acid or alkaline solutions

    NASA Astrophysics Data System (ADS)

    Althans, Daniel; Enders, Sabine

    2014-09-01

    For development of tailor made drug delivery systems using poly(N-isopropylacrylamide) hydrogels, the influence of acids and bases added to the aqueous solution on the swelling behaviour as function of concentration, temperature and kind of acid or base were investigated experimentally. The selected acids are formic, acetic, propionic, lactic, succinic, α-ketoglutaric and citric acid. The applied bases are sodium and potassium hydroxide. The swelling behaviour was characterised by the degree of swelling and by the uptake of acids by the hydrogel in the swollen state. In the case of weak acids the properties of the swollen hydrogel as well as the phase transition temperature and phase transition acid concentration depends on the type of acids, whereas the properties of the shrunken state do not depend on the acid used. In the case of strong bases, the properties of the shrunken and swollen state depend on the ionic strength, but not on the base applied.

  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. 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.

  1. Thermomechanical model of hydration swelling in smectitic clays: I two-scale mixture-theory approach

    NASA Astrophysics Data System (ADS)

    Murad, Márcio A.

    1999-06-01

    A thermomechanical theory of hydration swelling in smectitic clays is proposed. The clay is treated as a three-scale swelling system wherein macroscopic governing equations are derived by upscaling the microstructure. At the microscale the model has two phases, the disjoint clay platelets and adsorbed water (water between the platelets). At the intermediate (meso) scale (the homogenized microscale) the model consists of clay particles (adsorbed water plus clay platelets) and bulk water. At the macroscale the medium is treated as an homogenized swelling mixture of clay particles and bulk-phase water with thermodynamic properties defined everywhere within the macroscopic body. In Part I, the mesoscopic model governing the swelling of the clay particles is derived using a mixture-theoretic approach and the Coleman and Noll method of exploitation of the entropy inequality. Application of this procedure leads to two-scale governing equations which generalize the classical thermoelastic consolidation model of non-swelling media, as they exhibit additional physico-chemical and viscous-type terms accounting for hydration stresses between the adsorbed fluid and the clay minerals. In Part II the two-scale model is applied to a bentonitic clay used for engineered barrier of nuclear waste repository. The clay buffer is assumed to have monomodal character with most of the water essentially adsorbed. Further, partial results toward a three-scale thermomechanical macroscopic model including the bulk phase next to the swelling particles are derived by homogenizing the two-scale model with the bulk water. A notable consequence of this three-scale approach is that it provides a rational basis for the appearance of a generalized inter-phase mass transfer between adsorbed and bulk water.

  2. Synthesis of superporous hydrogels: hydrogels with fast swelling and superabsorbent properties.

    PubMed

    Chen, J; Park, H; Park, K

    1999-01-01

    We have been interested in the synthesis of hydrogels with fast swelling kinetics and superabsorbent properties. To increase the water absorption rate, interconnected pores were introduced to the hydrogels. Since the pore size in the dried hydrogels is in the order of hundreds of micrometers, these hydrogels are called "superporous" hydrogels. Superporous hydrogels were synthesized by crosslinking polymerization of various vinyl monomers in the presence of gas bubbles formed by the chemical reaction of acid and NaHCO3. The polymerization process was optimized to capture the gas bubbles inside the synthesized hydrogels. The use of the NaHCO3/acid system allowed easy control of timing for gelation and foam formation. We found that PF127 was the best foam stabilizer for most of the monomer systems used in our study. Scanning electron microscope (SEM) pictures showed interconnected pores forming capillary channels. The capillary channels, which were critical for fast swelling, were preserved during drying by dehydrating water-swollen hydrogels with ethanol before drying. The ethanol-dehydrated superporous hydrogels reached equilibrium swelling within minutes. The equilibrium swelling time could be reduced to less than a minute with the use of a wetting agent. In our study, water moisture was used as a wetting agent since the amount of moisture content in the dried hydrogels easily could be controlled. Preparation of superporous hydrogels using the right blowing system, foam stabilizer, drying method, and wetting agent makes it possible to reduce the swelling time to less than a minute regardless of the size of the dried gels. The superporous hydrogels can be used where fast swelling and superabsorbent properties are critical.

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

    PubMed

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

    2016-06-16

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

  4. ESEM study of the humidity-induced swelling of clay film.

    PubMed

    Carrier, Benoit; Wang, Linlin; Vandamme, Matthieu; Pellenq, Roland J-M; Bornert, Michel; Tanguy, Alexandre; Van Damme, Henri

    2013-10-15

    We measured the humidity-induced swelling of thin self-standing films of montmorillonite clay by a combination of environmental scanning electron microscopy (ESEM) and digital image correlation (DIC). The films were about 40 μm thick. They were prepared by depositing and evaporating a suspension of clay and peeling off the highly oriented deposits. The rationale for creating such original samples was to obtain mesoscopic samples that could be used to bridge experimentally the gap between the scale of the clay layer and the engineering scale of a macroscopic clay sample. Several montmorillonite samples were used: the reference clay Swy-2, the same clay homoionized with sodium or calcium ions, and a sodium-exchanged Cloisite. The edges of the clay films were observed by ESEM at various relative humidity values between 14% and 95%. The ESEM images were then analyzed by DIC to measure the swelling or the shrinkage of the films. We also measured the adsorption/desorption isotherms by weighing the film samples in a humidity-controlled environment. In order to analyze our results, we compared our swelling/shrinkage and adsorption/desorption data with previously published data on the interlayer spacing obtained by X-ray diffraction and with numerical estimates of the interlayer water obtained by molecular dynamics simulation. The swelling and the hysteresis of this swelling were found to be comparable for the overall macroscopic films and for the interlayer space. The same correspondence between film and interlayer space was observed for the amount of adsorbed water. This suggests that, in the range of relative humidities values explored, the films behave like freely swelling oriented stacks of clay layers, without any significant contribution from the mesoporosity. The relevance of this result for the behavior of clayey sedimentary rocks and the differences with the behavior of nonoriented samples (powders or compacted powders) are briefly discussed. PMID:24044513

  5. ESEM study of the humidity-induced swelling of clay film.

    PubMed

    Carrier, Benoit; Wang, Linlin; Vandamme, Matthieu; Pellenq, Roland J-M; Bornert, Michel; Tanguy, Alexandre; Van Damme, Henri

    2013-10-15

    We measured the humidity-induced swelling of thin self-standing films of montmorillonite clay by a combination of environmental scanning electron microscopy (ESEM) and digital image correlation (DIC). The films were about 40 μm thick. They were prepared by depositing and evaporating a suspension of clay and peeling off the highly oriented deposits. The rationale for creating such original samples was to obtain mesoscopic samples that could be used to bridge experimentally the gap between the scale of the clay layer and the engineering scale of a macroscopic clay sample. Several montmorillonite samples were used: the reference clay Swy-2, the same clay homoionized with sodium or calcium ions, and a sodium-exchanged Cloisite. The edges of the clay films were observed by ESEM at various relative humidity values between 14% and 95%. The ESEM images were then analyzed by DIC to measure the swelling or the shrinkage of the films. We also measured the adsorption/desorption isotherms by weighing the film samples in a humidity-controlled environment. In order to analyze our results, we compared our swelling/shrinkage and adsorption/desorption data with previously published data on the interlayer spacing obtained by X-ray diffraction and with numerical estimates of the interlayer water obtained by molecular dynamics simulation. The swelling and the hysteresis of this swelling were found to be comparable for the overall macroscopic films and for the interlayer space. The same correspondence between film and interlayer space was observed for the amount of adsorbed water. This suggests that, in the range of relative humidities values explored, the films behave like freely swelling oriented stacks of clay layers, without any significant contribution from the mesoporosity. The relevance of this result for the behavior of clayey sedimentary rocks and the differences with the behavior of nonoriented samples (powders or compacted powders) are briefly discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  8. 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.

  9. Bilateral optic disc swelling as a presenting sign of superior sagittal sinus thrombosis

    PubMed Central

    Pakter, Grant Jason

    2012-01-01

    The case of a 59-year-old Caucasian man who presented with a 6-week history of intermittent blurring of vision and diplopia is reported. Fundoscopy revealed asymmetrical, bilateral optic disc swelling with peripapillary haemorrhages. An initial CT scan and D-dimer level were reported as normal. A subsequent MRI revealed a recanalising superior sagittal sinus thrombosis. Cerebral venous sinus thrombosis is a rare and potentially fatal condition. The author suggests that it should be part of the differential diagnosis of bilateral optic disc swelling and that a normal unenhanced CT scan and D-dimer would not rule out this potentially devastating condition. PMID:22987907

  10. A One-dimensional Transient Model of Down-flow Through a Swelling Packed Porous Bed

    SciTech Connect

    SHADDAY, MARTIN

    2004-08-13

    A transient model of down-flow through an ion exchange column in which the resin swells has been developed. The model is herein described and results are presented. Wall friction can lead to high bed stresses when the resin in columns with high length to diameter ratios swells. These stresses can lead to high and potentially excursive hydraulic pressure drops along a column. A non-dimensional grouping that effectively correlates the final steady-state hydraulic behavior of a column with the resin compressibility, column geometric, and flow parameters has been determined.

  11. 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. PMID:22677026

  12. 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.

  13. 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.

  14. Kinetics of interlayer ion migration in non-swelling clays: An atomic-scale study

    NASA Astrophysics Data System (ADS)

    Lammers, L. N.; Kolluri, K.

    2015-12-01

    Clay-rich geologic repositories serve as hosts for fossil methane reserves and as traps for contaminant radionuclides and sequestered CO2. Despite the abundance of non-swelling clay minerals in sedimentary formations, the mechanisms of ion exchange and mass transport mediated by these minerals are not well understood. Ion exchange kinetics in collapsed clays are characterized by a long tail of slow exchange, which suggests that interlayer ions can exchange with the bulk solution. Recent High-Resolution TEM evidence suggests that Cs+ ion exchange K+ in collapsed interlayers leads to interstratified structures, where entire interlayers are completely exchanged while others remain pristine [Okamura T et al., (2005) Microscopy 6365-72]. This phenomenon could be explained by kinetic feedbacks arising when a larger ion substitutes for a smaller one, although the details of this exchange mechanism are currently unknown. We investigated the kinetics and mechanisms of interlayer cation migration in illite (K0.7Al2[Al0.7Si3.3O10](OH)2) using molecular simulations. A Monte Carlo scheme was used to distribute interlayer K ions, and these ions were found to prefer sites neighboring two or more Al3+ substitutions in the tetrahedral sheets. Interlayer K+ ion migration between stable ditrigonal cavity sites was observed directly in molecular dynamics simulations performed at temperatures ranging from 500 K to 900 K and at constant volume. The Climbing Image Nudged Elastic Band method was used to determine the activation energy barrier on 660 K+ ion migration paths. Interlayer ions were observed to migrate between stable lattice sites with migration barriers of 2.35 ± 1.06 eV. Only about 20% of this variation is statistically explained by the distribution of charge deficit sites in the layer caused by Al3+ substitution for Si4+. Remarkably, we find that migration barriers decrease as we increase interlayer spacing. These results suggest that frayed edge sites - local regions with

  15. Field Method for Measuring the Shrinkage/Swelling Dynamics of Cracks Using a Low-Cost ``Crack-o-meter''

    NASA Astrophysics Data System (ADS)

    Stewart, R. D.; Abou Najm, M. R.; Rupp, D. E.; Selker, J. S.

    2010-12-01

    Shrinking/swelling soils are characterized by transient crack networks which function as dominant controls on the partitioning of surface and subsurface flow, the rate and depth of percolation, and evaporation rates. For such soils, understanding the dynamics of cracks is critical to accurately quantify their influence on groundwater recharge, stream-flow generation, and solute transport, among other component of a site’s hydrology. We propose a low-cost method for measuring transient crack-volume using a sealed plastic bag connected by a hose to a PVC standpipe. The empty bag is placed into the crack, and then water is added via the standpipe, until the bag has expanded to the boundaries of the crack and some water remains in the standpipe. As the crack shrinks or swells, its volume changes, causing water displacement within the bag, which is measured as a corresponding change in water level in the standpipe. An automated level logger within the standpipe is used to record changes in water level, which are converted to volumetric changes from the known internal cross-sectional area of the standpipe. The volume of water filling the bag is accurately measured at the start and completion of the experiment (to check for leakage). Adding the startup volume to the cumulative temporal volumetric change in the standpipe provides a simple and accurate method for monitoring transient crack volume. Currently, the design is undergoing preliminary testing in a field site in Ninhue, Chile, and field and laboratory testing in Corvallis, Oregon. Initial results from the Chilean field site suggest that the crack-o-meters are responding to the closing of cracks, but further effort is needed to calibrate and validate the results. We hope that these low-cost “crack-o-meters” will become useful and simple tools for researchers to quantify temporal changes in crack volume with the objective of incorporating these results into hydrological modeling efforts.

  16. Role of south Indian Ocean swells in modulating the north Indian Ocean wave climate through modelling and remote sensing

    NASA Astrophysics Data System (ADS)

    Samiksha, S. V.; Vethamony, P.; Aboobacker, V. M.; Rashmi, R.

    2012-04-01

    Implementation and validation of a third generation wave model, Wavewatch III was used to study the characteristics of the south Indian ocean swells and their propagation in the north Indian Ocean. The NCEP reanalysis wind data (2.5° x 2.5°) has been used to generate the wind waves for the entire Indian Ocean during 2006 - 2007. The modelled wave parameters have been compared with measured buoy data and with merged altimeter data. The model results show good agreement with the buoy and altimeter data. A case study is carried out to study the propagation of the swells generated at the roaring 40°S in the Indian Ocean during May 2007. The "southern swell" occurred during May 2007 has been successfully reproduced in the wave model, which confirmed by the comparison of modelled significant wave heights with the merged altimeter significant wave heights. These swells were generated in the Atlantic ocean near the southern tip of South Africa and propagated towards the north Indian Ocean. These waves touches the Madagascar region and further hits the La Reunion islands after three days thus creating numerous damages near the islands. The magnitude of the swell is around 15m near the generation area and it reduces to around 6m near the La Reunion islands while propagating towards the north Indian Ocean. Further the swell energy is spataially distributed in the northern and southern Indian Ocean. The study reveals that the swells generated in the roaring forties and propagating in the SW/SSW direction influences more to Bay of Bengal than Arabian Sea. This occurs during pre-monsoon season primarily because large scale winds are weak in the north Indian Ocean during this period and hence swells from south Indian Ocean dominates at this time. The case of "southern swell" also happened to be at the same season. Further wave parameters were extracted at few locations in the northern Indian Ocean to study the impact of May 2007 swells on the wave climate. An average of around

  17. Arm/Hand Swelling and Perceived Functioning among Breast Cancer Survivors 12 Years Post-diagnosis: CALGB 79804

    PubMed Central

    Oliveri, Jill M.; Day, Jeannette M.; Alfano, Catherine M.; Herndon, James E.; Katz, Mira L.; Bittoni, Marisa A.; Donohue, Kathleen; Paskett, Electra D.

    2014-01-01

    Introduction Lymphedema is an under-reported and debilitating consequence of axillary node dissection among breast cancer survivors. This study describes the characteristics of arm and hand swelling in relation to perceived physical and mental health functioning among breast cancer survivors 9–16 years post-diagnosis who previously participated in a clinical trial coordinated by the Cancer and Leukemia Group B (CALGB 8541). Methods Eligible survivors of CALGB 8541 completed questionnaires assessing demographics, arm/hand swelling, perceived physical functioning, and mental health. Results 245 women (94% white, mean age=63, on average 12.4 years post-diagnosis) completed questionnaires (participation rate=78%). Seventy-five women (31%) reported arm/hand swelling since their surgery. Of these women, 76% reported current swelling and half reported constant swelling, mainly in the upper arm. Swelling was reported as mild or moderate in 88% of the women. Women who reported severe swelling had significantly worse physical functioning and trended toward worse depressive symptoms and poorer mental health (lower mental SF-36 scores) as well. Activity-limiting swelling was also significantly associated with worse physical functioning. Although swelling interfered with wearing clothing (36%) and perceptions about general appearance (32%), only 37% of women sought treatment for swelling. Conclusions Arm/hand swelling is a chronic problem for a subgroup of long-term survivors of breast cancer, negatively affecting physical functioning. Implications for Cancer Survivors Educational efforts are needed as part of a comprehensive survivorship care plan to raise awareness about lymphedema so that survivors may identify this complication, seek treatment early, and potentially improve their physical functioning. PMID:18792786

  18. 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.

  19. 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

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

    PubMed

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

    2015-05-19

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

  1. 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...

  2. 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.

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

    PubMed

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

    2013-01-01

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

  4. 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.

  5. 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.

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

    PubMed

    Graf, P; Juto, J E

    1994-01-01

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

  7. Contribution of polymeric swelling to the overall response of capacitive gas sensors.

    PubMed

    Altenberend, U; Oprea, A; Barsan, N; Weimar, U

    2013-08-01

    A new method for investigation of the swelling of polymers on exposure to gas or vapour has been devised and tested. It uses an optical profilometer (based on the chromatic aberration of a lens system) which is integrated into a computer-controlled gas-dosing and mixing setup. Gas and/or vapour concentration-dependent measurements have been carried out for thick layers of the polymers commonly used in gravimetric and capacitive gas sensors: poly(acrylic acid) (PAA), poly(vinyl pyrrolidone) (PVP), poly(ether urethane) (PEUT), and polydimethylsiloxane (PDMS). The thickness of PAA, PVP, and PEUT films changed significantly on exposure to humidity. These data have been used to derive the sorption isotherms of the respective polymers, which were found to be Henry or Flory-Huggins isotherms. Comparison of the geometrical (swelling) responses with capacitive responses revealed a strong correlation. The correlation, which occurs because both types of response are proportional to the water content of the polymer, is also valid for polymers with nonlinear gas responses. Finally the geometrical and electrical characteristics of the capacitive samples were used to explain the dependence of the capacitive response of different polymers on the concentration of the target gas or vapour. In this way was deduced that PDMS, which does not swell on exposure to humidity, swells in the presence of 2,3-dimethylpentane, for which no profilometer evaluations are yet available.

  8. 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.

  9. Evaluation of hypoxic swelling of human cornea with high speed ultrahigh resolution optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Bizheva, Kostadinka; Hyun, Chulho; Eichel, Justin; Hariri, Sepideh; Mishra, Akshaya; Clausi, David; Fieguth, Paul; Simpson, Trefford; Hutchings, Natalie

    2009-02-01

    Hypoxia induced corneal swelling was observed and evaluated in healthy human volunteers by use of high speed, ultrahigh resolution optical coherence tomography (UHROCT). Two dimensional corneal images were acquired at a speed of 47,000 A-scans/s with 3µm x 10µm (axial x lateral) resolution in corneal tissue. The UHROCT tomograms showed clear visualization of all corneal layers, including the Bowman's layer and the Descemet's membrane - Endothelium complex. A segmentation algorithm was developed and used for automatic detection of the boundaries of the different corneal layers and evaluation the individual layer thickness as a function of location. Corneal hypoxia was induced by wear of a soft contact lens (SCL) and an eye patch by 2 healthy volunteers for duration of 3 hours. The thickness of all corneal layers was measured as a function of time, prior to, with and after removal of the SCL. Results from the hypoxia study showed different rates of swelling and de-swelling of the individual corneal layers. About 10% increase in the total cornea thickness was observed, similar to the changes in the stroma, the Bowman's membrane swelled by 20%, while no significant change in the thickness was observed in the Descemet's - Endothelium complex.

  10. 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. PMID:27386731

  11. 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. PMID:27479889

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

    SciTech Connect

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

    1999-08-03

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

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

    NASA Astrophysics Data System (ADS)

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

    2000-03-01

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

  15. 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. PMID:24216230

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  17. 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...

  18. Swelling and polymer erosion for poly(ethylene oxide) tablets of different molecular weights polydispersities.

    PubMed

    Körner, Anna; Larsson, Anette; Andersson, Asa; Piculell, Lennart

    2010-03-01

    The aim of the study was to determine and compare the degree of swelling and the swelling kinetics of poly(ethylene oxide) (PEO) hydrophilic matrix tablets without any additives for matrixes with different molecular weight polydispersities. A wide range of "mixed" polydisperse PEO tablets were obtained by mixing two PEO batches with average molecular weights of 10(5) and 2 x 10(6), respectively. These were compared with "single-batch" tablets with narrower mono-modal molecular weight distributions. A texture analyzer (TA) was used to determine, during the entire dissolution process, the thickness of the "gel" layer, the height of the dry tablet core and the total height of the tablet. The release of polymer from the tablet was also measured using a chromatographic method. Both the swelling histories and the polymer release rates varied strongly with molecular weight and agitation rate, whereas the rate of dissolution of the solid core varied much less with molecular weight. For single-batch and mixed tablets, tuned to give the same release rate, the swelling process was found to be very similar, regardless of the molecular polydispersity (between 1.2 and 8.8). These results support a previously proposed dissolution model with the key assumption of a constant critical viscosity, independent of time or polymer molecular weight, at the surface of the gel layer of a dissolving tablet. PMID:19718760

  19. Protein composition and movements of membrane swellings associated with primary cilia

    PubMed Central

    Mohieldin, Ashraf M.; Haymour, Hanan S.; Lo, Shao T.; AbouAlaiwi, Wissam A.; Atkinson, Kimberly F.; Ward, Christopher J.; Gao, Min; Wessely, Oliver

    2015-01-01

    Dysfunction of many ciliary proteins has been linked to a list of diseases, from cystic kidney to obesity and from hypertension to mental retardation. We previously proposed that primary cilia are unique communication organelles that function as microsensory compartments that house mechanosensory molecules. Here we report that primary cilia exhibit membrane swellings or ciliary bulbs, which based on their unique ultrastructure and motility, could be mechanically regulated by fluid-shear stress. Together with the ultrastructure analysis of the swelling, which contains monosialodihexosylganglioside (GM3), our results show that ciliary bulb has a distinctive set of functional proteins, including GM3 synthase (GM3S), bicaudal-c1 (Bicc1), and polycystin-2 (PC2). In fact, results from our cilia isolation demonstrated for the first time that GM3S and Bicc1 are members of the primary cilia proteins. Although these proteins are not required for ciliary membrane swelling formation under static condition, fluid-shear stress induced swelling formation is partially modulated by GM3S. We therefore propose that the ciliary bulb exhibits a sensory function within the mechano-ciliary structure. Overall, our studies provided an important step towards understanding the ciliary bulb function and structure. PMID:25650235

  20. Effect of silica nanoparticles on clay swelling and aqueous stability of nanoparticle dispersions.

    PubMed

    Pham, Hieu; Nguyen, Quoc P

    2014-01-01

    The results of the effects of electrolyte type and concentration, nanoparticle concentration, pH, and temperature on the mobility and aqueous stability of polyethylene glycol (PEG)-coated silica nanoparticles are presented. Nanoparticle mobility was evaluated based on the ability to inhibit montmorillonite swelling in aqueous solutions through visual swelling tests, and the results were quantified in terms of the swelling index. The presence of PEG-coated silica nanoparticles was found to have a positive influence on the inhibition of clay swelling only in the presence of electrolytes. Quantification of nanoparticle stability in the presence of montmorillonite particles was achieved using ultraviolet-visible (UV-vis) spectrophotometry. At the highest concentration of montmorillonite dispersion studied, interaction between the dispersed montmorillonite particles and PEG-coated silica nanoparticles resulted in nanoparticle aggregation as indicated by increased turbidity and absorbance readings. Both nanoparticle concentration and montmorillonite dispersion concentration, in addition to the presence and concentration of NaCl, were found to strongly influence the stability of the mixture.