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Sample records for conventional penetrating keratoplasty

  1. Clinical Outcomes of Penetrating Keratoplasty Performed with the VisuMax Femtosecond Laser System and Comparison with Conventional Penetrating Keratoplasty

    PubMed Central

    Kamiya, Kazutaka; Kobashi, Hidenaga; Shimizu, Kimiya; Igarashi, Akihito

    2014-01-01

    Purpose To assess the clinical outcomes of femtosecond laser-assisted keratoplasty (FLAK) using the VisuMax femtosecond laser system, and to compare them with those of conventional penetrating keratoplasty (PK). Methods We retrospectively examined 20 eyes of 20 consecutive patients undergoing FLAK and 20 eyes of 20 age- and diagnosis-matched patients undergoing conventional PK. We quantitatively assessed corneal astigmatism, refractive astigmatism, and corrected visual acuity, 1, 3, and 6 months postoperatively, and endothelial cell density 6 months postoperatively. Results Corneal and refractive astigmatism after FLAK were significantly lower after FLAK than that after conventional PK at 3 and 6 months postoperatively (p = 0.04 and p = 0.03, respectively, Mann-Whitney U test). FLAK provided significantly faster visual recovery than conventional PK at 1 month postoperatively (p = 0.02), but not at 3 and 6 months postoperatively (p = 0.52 and p = 0.80, respectively). We found no significant differences in the change in endothelial cell density between the two groups (p = 0.30). Conclusions FLAK using the VisuMax femtosecond laser system induces significantly less corneal and refractive astigmatism than conventional PK, and provides significantly faster visual recovery in the early postoperative period, possibly because the geometry of the donor-recipient matching is more physiological and requires less tight sutures. It is suggested that FLAK has advantages over conventional PK, in terms of astigmatism and fast visual recovery. PMID:25126741

  2. Endophthalmitis after penetrating keratoplasty.

    PubMed

    Guss, R B; Koenig, S; De La Pena, W; Marx, M; Kaufman, H E

    1983-05-01

    Of 445 eyes (305 of which were aphakic) that underwent penetrating keratoplasty, 11 developed endophthalmitis, three immediately after surgery, two after subsequent secondary surgery, and six after late ulceration of the transplanted cornea. The diagnosis was based clinically on the loss of the red reflex and vitreous opacification, and was confirmed by culture of vitreous aspirate. All patients who developed endophthalmitis were aphakic and had received corticosteroids at the time of infection; most had undergone previous ocular surgery. These patients differed from those previously described with this condition because neither the donor tissue nor the storage medium was the source of infection. Treatment included intracameral, systemic, and topical administration of antibiotics. When the endophthalmitis originated from a corneal ulcer in a graft, the infected tissue was replaced with a new transplant. Despite treatment, the final visual outcomes were not good. One eye had a final visual acuity of 20/200 and one eye had a final visual acuity of 20/400. Three eyes had light perception and six eyes had no light perception. One eye was eventually enucleated. PMID:6342401

  3. Microbial keratitis after penetrating keratoplasty.

    PubMed

    Bates, A K; Kirkness, C M; Ficker, L A; Steele, A D; Rice, N S

    1990-01-01

    Thirty cases of microbial keratitis after penetrating keratoplasty were reviewed to examine the associated risk factors, the spectrum of pathogens and the prognosis for graft survival and visual outcome. The indications for keratoplasty in this group differed markedly from those for all corneal grafts performed with a much higher incidence of previous microbial keratitis and of herpes simplex keratitis. A positive culture was obtained in 93% of cases and in contrast to microbial keratitis overall, Gram positive organisms predominated particularly streptococcus pneumoniae and staphylococcus aureus. Risk factors identified were loose or broken sutures, graft decompensation and a poor ocular surface environment. There was a poor prognosis for graft survival with only 23% of cases retaining a clear graft. Overall 53% of cases were regrafted. PMID:2323481

  4. Surface keratopathy after penetrating keratoplasty.

    PubMed Central

    Feiz, V; Mannis, M J; Kandavel, G; McCarthy, M; Izquierdo, L; Eckert, M; Schwab, I R; Torabian, S; Wang, J L; Wang, W

    2001-01-01

    PURPOSE: To determine the type and prevalence of epithelial abnormalities in the intermediate postoperative period after penetrating keratoplasty and to define the donor and recipient variables that influence the status of the graft epithelium. DESIGN: Prospective cohort study. METHODS: We prospectively followed the clinical course of 80 patients after penetrating keratoplasty. We monitored the status of the corneal epithelium for 3 months after surgery using slit-lamp biomicroscopy and fluorescein staining of the epithelium. Donor characteristics, recipient preoperative and postoperative variables, and postoperative medications were recorded. Epithelial abnormalities were analyzed against these variables by using univariate and combined statistical models to determine the impact of each variable on postoperative epithelial pathology. Main outcome measures included punctate keratopathy, macro-epithelial defects, hurricane keratopathy, rim defects, and filamentary keratopathy. RESULTS: Sixty-three percent of all patient visits demonstrated punctate epithelial keratopathy (PEK). Hurricane keratopathy (51%) and filamentary keratopathy (14%) constituted the next most commonly observed abnormalities. Older recipient age and the use of topical antibiotics were associated with a higher prevalence of punctate epithelial keratopathy. The odds ratio (OR) for a 1-year increase in age is 1.0276 (95% CI, 1.1013-1.0442), and the OR for using topical antibiotics is 6.9028 (95% CI, 3.1506-15.1239). Use of topical ofloxacin and increased time after surgery were associated with lower prevalence of punctate keratopathy; ORs were 0.9806 (95% CI, 0.9736-0.9876) and 0.3662 (95% CI, 0.1688-0.7943), respectively. Decreased corneal sensation and the presence of anterior blepharitis preoperatively were associated with an increase in hurricane keratopathy; ORs were 8.8265 (CI, 2.3837-32.6835) and 3.2815 (CI, 1.7388-6.1931), respectively. Total storage time for the donor material was also

  5. Descemet stripping automated endothelial keratoplasty in a child after failed penetrating keratoplasty.

    PubMed

    Kymionis, George D; Kankariya, Vardhaman P; Diakonis, Vasilios F; Karavitaki, Alexandra E; Siganos, Charalampos S; Pallikaris, Ioannis G

    2012-02-01

    Use of Descemet stripping automated endothelial keratoplasty (DSAEK) has been reported in children for the treatment of postoperative endothelial decompensation and Descemet membrane break after forceps delivery. Rapid visual recovery and minimally induced postoperative astigmatism make DSAEK preferable to penetrating keratoplasty for the management of isolated endothelial disorders in this age group. We present a case of DSAEK in a 4-year-old boy for the management of irreversible endothelial rejection after penetrating keratoplasty. Three months after the procedure, the cornea remained clear with the donor button in place. PMID:22244506

  6. Spontaneous wound dehiscence after penetrating keratoplasty

    PubMed Central

    Foroutan, Alireza; Tabatabaei, Seyed Ali; Behrouz, Mahmoud Jabbarvand; Zarei, Reza; Soleimani, Mohammad

    2014-01-01

    Spontaneous wound separation may be developed even months after suture removal especially in the context of long-term corticosteroid therapy. A 68-year-old Caucasian woman presented to our cornea clinic with spontaneous wound dehiscence after her third penetrating keratoplasty (PKP) which was performed three years ago. An Ahmed glaucoma valve (New World Medical, Ranchos Cucamonga, CA) was inserted ten months after the third PKP, which successfully controlled intraocular pressure (IOP). At the examination, the last sutures were removed eight months ago and she was using flourometholone 0.1 % (Sina Darou, Tehran, Iran) with a dose of once a day. There was one quadrant of wound dehiscence from 8 to 11 òclock associated with anterior wound gape and severe corneal edema. Resuturing was performed for the patient. At the one month examination, the corneal edema was resolved and best corrected visual acuity was 20/200 mainly due to previous glaucomatous optic neuropathy. Caution about the prolonged use of corticosteroids is necessary. Topical immunosuppressives could be a promising choice in this field. PMID:25349814

  7. Spontaneous wound dehiscence after penetrating keratoplasty.

    PubMed

    Foroutan, Alireza; Tabatabaei, Seyed Ali; Behrouz, Mahmoud Jabbarvand; Zarei, Reza; Soleimani, Mohammad

    2014-01-01

    Spontaneous wound separation may be developed even months after suture removal especially in the context of long-term corticosteroid therapy. A 68-year-old Caucasian woman presented to our cornea clinic with spontaneous wound dehiscence after her third penetrating keratoplasty (PKP) which was performed three years ago. An Ahmed glaucoma valve (New World Medical, Ranchos Cucamonga, CA) was inserted ten months after the third PKP, which successfully controlled intraocular pressure (IOP). At the examination, the last sutures were removed eight months ago and she was using flourometholone 0.1 % (Sina Darou, Tehran, Iran) with a dose of once a day. There was one quadrant of wound dehiscence from 8 to 11 òclock associated with anterior wound gape and severe corneal edema. Resuturing was performed for the patient. At the one month examination, the corneal edema was resolved and best corrected visual acuity was 20/200 mainly due to previous glaucomatous optic neuropathy. Caution about the prolonged use of corticosteroids is necessary. Topical immunosuppressives could be a promising choice in this field. PMID:25349814

  8. Simultaneous Penetrating Keratoplasty and Cataract Surgery

    PubMed Central

    Javadi, Mohammad-Ali; Feizi, Sepehr; Moein, Hamid-Reza

    2013-01-01

    Purpose To determine the clinical outcomes of simultaneous penetrating keratoplasty (PK), cataract removal and intraocular lens implantation (triple procedure), and to compare the safety and efficacy of two different cataract extraction techniques during the course of PK. Methods This retrospective comparative study was conducted on patients who had undergone a triple procedure. The technique of cataract extraction was either open- sky extracapsular cataract extraction (ECCE) or phacoemulsification (PE). In the ECCE group, the posterior chamber intraocular lens (PCIOL) was implanted in the ciliary sulcus, while in the PE group PCIOLs were fixated within the capsular bag. Outcome measures included best spectacle corrected visual acuity (BSCVA), refractive results, graft clarity and complications. Results Seventy-six eyes of 69 consecutive patients with mean age of 61.4±14.2 years were enrolled. Mean follow-up period was 61.4±37.2 months over which mean BSCVA was significantly improved from 1.40±0.68 to 0.44±0.33 LogMAR (P<0.001). Mean postoperative spherical equivalent refractive error was -2.13±3.02 D, which significantly differed from the target refraction (-0.73±0.29 D, P=0.004). At final follow-up, 89.5% of the corneal grafts remained clear. Conclusion The triple procedure is a safe and effective approach to restore vision in patients with coexisting corneal pathologies and cataracts. However, unacceptable postoperative refractive error can be anticipated. PMID:23825711

  9. Mersilene (polyester), a new suture for penetrating keratoplasty.

    PubMed

    Ramselaar, J A; Beekhuis, W H; Rijneveld, W J; van Andel, M V; Dijk, F; Jongebloed, W L

    1992-01-01

    Mersilene (polyester monofilament) seems to be suitable for penetrating keratoplasty because it is strong, shows no degradation by ultraviolet light, is insoluble, so that it can be left in situ, and offers the possibility of regulating postoperative astigmatism by suture adjustment. In 12 patients penetrating keratoplasty was performed with the combined interrupted/running suturing technique, using eight interrupted nylon 10-0 sutures and one running Mersilene 11-0 suture. The results were compared with those of 25 patients in whom eight interrupted nylon 10-0 sutures and one running nylon 11-0 suture were used. Six months after penetrating keratoplasty, no differences could be found between the two groups in keratometric astigmatism, visual acuity or slitlamp findings. In three patients postoperative adjustment of the running Mersilene suture reduced astigmatism by 50, 90 and 100% respectively. In an animal study the behaviour of Mersilene in the cornea was evaluated by slitlamp examination, histology and electron-microscopy. The tissue response to Mersilene was minimal. Considering the resemblance to nylon in clinical findings, minimal tissue response, lack of biodegradation and possibility of regulating postoperative astigmatism by suture adjustment, Mersilene seems to be a suitable material for penetrating keratoplasty. PMID:1305032

  10. Use of penetrating keratoplasty in acute bacterial keratitis.

    PubMed Central

    Hill, J C

    1986-01-01

    Twenty-three patients with bacterial keratitis had penetrating keratoplasties performed for deep indolent ulceration or descemetoceles, during the acute period. The period in hospital (17.6 days) was significantly lower than for a control group (35.4 days) who were treated medically and had subsequent grafts. The number of grafts remaining clear was similar, 70% and 72% respectively. Eleven patients (48%) of those who had an acute graft achieved corrected visual acuities of 6/12 or better. No cases of reinfection occurred and no eyes were lost. Images PMID:3521719

  11. Penetrating keratoplasty and graft rejection in eight horses.

    PubMed

    Makra, Zita; Tuboly, Tamás; Bodó, Gábor

    2013-06-01

    The aim of this study was to describe long-term follow-up and difference in immune reactions in the tear film following penetrating keratoplasty (PK) in horses when differently preserved corneas were utilised. This report describes for the first time the use of corneal grafts preserved in tissue culture media in equine PK. Eight experimental horses with normal eyes were included and freshly harvested, frozen or preserved corneal grafts were used for the PK. The graft-taking technique and storage, PK surgery, postoperative treatments and complications are described. The mean postoperative follow-up time was 286 days. Tear film samples taken before and periodically after surgery were measured for IgM, IgG and IgA contents by direct ELISA. All grafts were incorporated into the donor horse but were rejected to some degree. The differently harvested corneal grafts healed in the same manner and looked similar. Preoperatively, the clear corneas meant low risk for graft failure, and the fresh or stored tissues provided intact endothelium, although there were no clear graft sites postoperatively. The presence of IgA, IgG and IgM was demonstrated in the tear film from the early postoperative period. IgG levels were lower than IgA or IgM and had a constant baseline in every case, as IgA and IgM had great variability with time and an individual pattern in each eye. PMID:23661385

  12. Staged Penetrating Sclerokeratoplasty and Penetrating Keratoplasty for Management of Advanced Acquired Anterior Staphyloma

    PubMed Central

    de la Torre-Gonzalez, Enrique; de León Ascencio, Carolina Ponce

    2011-01-01

    Herein we describe a staged surgical technique consisting of penetrating sclerokeratoplasty (PSKP) followed by penetrating keratoplasty (PKP) and present its clinical course and complications over two years of follow-up. A 23-year-old man presented with cosmetically unacceptable protrusion of the globe corresponding to the cornea and sclera. PSKP was performed transplanting a full-thickness beveled 13 mm corneoscleral tectonic graft. Hypotony developed subsequently and was successfully managed medically, however corneal graft failure occurred. After 15 months, a 7.5 mm PKP was performed for optical reasons, which subsequently remained clear with a healthy epithelium. In this particular case, cosmetic, tectonic, therapeutic, and optical requirements were met. PSKP is a surgical procedure which entails a high rate of complications but may be the only alternative when the main goal of intervention is restoration of the globe in complicated cases such as our patient. PMID:22454726

  13. Long term observation of low-power diode laser welding after penetrating keratoplasty in human patients

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Matteini, Paolo; Pini, Roberto; Menabuoni, Luca; Lenzetti, Ivo

    2010-02-01

    Low power diode laser welding is a recently developed technique used as a support tool for conventional suturing in ophthalmic surgery. The main application is in penetrating keratoplasty: in the last four years (2005-2009), clinical trials were performed at the Ophthalmic Department of Prato, Italy). In penetrating keratoplasty, diode laser welding is used to assure the transplanted corneal button in its final position. The donor tissue is positioned in the recipient eye and 8-16 single stitches are apposed. The surgical wound is then stained with a saturated (10% w/w) sterile water solution of Indocyanine Green (ICG), it is washed with sterile water and then a diode laser (810 nm, 13 W/cm2) is used to induce the sealing of the wound. The laser light induces a thermal effect, localized in the stained tissue. In vivo and ex vivo studies in animal models evidenced that welding induces a modification of the corneal collagen architecture through the wound walls, thus enabling a short healing time and a good restoration of the tissue. In this study on human subjects, we confirmed the results evidenced in animal models, by morphological observations. In two cases out of 60, transplant rejection was observed. It was thus possible to study the efficacy of laser welding in the closure of the wound one year after implant. Direct morphological observation evidenced good strengthens of the welded tissue. Histological analysis pointed out a good restoration of the regular collagen architecture at the external perimeter of the corneal button, where laser welding was performed, showing the occurrence of a correct and effective wound healing process.

  14. Shifting bubble-guided sutureless technique for performing descemetorhexis for retained Descemet's membrane after penetrating keratoplasty.

    PubMed

    Khokhar, Sudarshan; Agarwal, Tushar; Gupta, Shikha; Sehra, Srivats; Panda, Anita

    2014-02-01

    We describe the use of anterior segment optical coherence tomography in the diagnosis of inadvertent retention of Descemet's membrane (DM) after penetrating keratoplasty, and a novel technique for its removal in a case of congenital hereditary endothelial dystrophy. In this technique, we use a modification of the shifting bubble technique, commonly used in deep anterior lamellar keratoplasty where a viscocohesive ophthalmic viscosurgical device is injected into the false anterior chamber which causes migration of the central air bubble placed in the anterior chamber peripherally and helps in confirming the correct space. The DM is then peeled in a circular fashion with the help of 23-G vitreoretinal micro forceps. PMID:23456512

  15. Indications and Visual Outcome of Penetrating Keratoplasty in Tertiary Eye Care Institute in Uttarakhand

    PubMed Central

    Gupta, Neeti; Dhasmana, Renu; Nagpal, Ramesh Chander; Bahadur, Harsh; Maitreya, Amit

    2016-01-01

    Introduction Corneal blindness forms significant proportion of visual blindness in developing countries and penetrating keratoplasty (PK) can restore vision for this. The prognosis of PK is dependent on the corneal diseases responsible for corneal blindness. Aim To evaluate the indications and visual outcome of PK in tertiary eye care institute in Uttarakhand. Materials and Methods Data was reviewed from the medical records of 145 PK done in Department of Ophthalmology, Himalayan Institute of Medical Sciences from January 2012 to October 2014. Analysis of data was done for evaluation of the indications and visual outcome by Paired student’s t-test for hypothesis testing of grouped values of preoperative and last follow-up best corrected visual acuity in cases of optical and therapeutic grafts. A p-value < 0.05 was considered statistically significant. Results In this study data of 145 eyes of 138 patients was reviewed. The most common indication for keratoplasty was corneal scarring including adherent leucoma 48 (33.10%). Therapeutic keratoplasty was done for 33 cases with maximum 30(20.68%) cases of infectious keratitis. One case of tectonic graft was included in therapeutic keratoplasty group for analysis. There was statistically significant difference (p=.0001) in best corrected visual acuity improvement from 1.39 logMAR+ 0.022(SD) preoperatively to 0.367 logMAR+0.44(SD) postoperatively and 1.4 logMAR+.000(SD) preoperatively to 0.16 logMAR+0.57(SD) postoperatively for optical and therapeutic grafts respectively. Conclusion Infective keratitis either active or healed was the major indication for keratoplasty. Poor prognosis indications were most common in this part of the country. The visual outcome following corneal transplantation was encouraging particularly in cases of optical keratoplasty. PMID:27504319

  16. Long-term comparison of full-bed deep anterior lamellar keratoplasty and penetrating keratoplasty in treating keratoconus*

    PubMed Central

    Zhang, Yong-ming; Wu, Shuang-qing; Yao, Yu-feng

    2013-01-01

    Objective: To compare postoperative outcomes of full-bed deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in treating keratoconus. Methods: Seventy-five eyes of 64 patients who received full-bed DALK and 52 eyes of 51 patients who received PK between June 2000 and August 2010 were included in this retrospective study. Full-bed DALK was performed using Yao’s hooking-detaching technique. PK was performed using a standard technique. Intraoperative and postoperative complications, visual acuity, rejection, graft survival, endothelial cell density, corneal sensation recovery, and re-innervation were compared between the two groups. Results: A best correct visual acuity of 0.5 or better was achieved in 90.7% of eyes after full-bed DALK and in 92.3% of eyes after PK (P=0.75). By the fifth postoperative year, graft endothelial cell loss reached 34.6% in the PK group vs. 13.9% in the full-bed DALK group (P<0.001). There were no statistical differences in corneal sensitivity recovery or corneal re-innervation between the groups (P>0.05). Intraoperative microperforation occurred in seven out of 75 (9.3%) eyes with a temporally postoperative double anterior chamber in two eyes in the full-bed DALK group. Postoperative complications in the PK vs. the full-bed DALK groups respectively were: rejection (7.7% vs. 0%, P=0.015), high intraocular pressure (IOP) (46.2% vs. 1.3%, P<0.001), secondary glaucoma (9.6% vs. 0%, P=0.006), complicated cataract (19.2% vs. 0%, P<0.001), and wound dehiscence (9.6% vs. 0%, P=0.006). Conclusions: Both full-bed DALK and PK can offer long-term satisfactory visual outcomes for keratoconus. Graft rejection, secondary glaucoma, complicated cataracts, and constant endothelial cell loss were observed in eyes only after PK. PMID:23645180

  17. Infectious crystalline keratopathy caused by Cladosporium sp. after penetrating keratoplasty: a case report

    PubMed Central

    Stock, Ricardo Alexandre; Bonamigo, Elcio Luiz; Cadore, Emeline; Oechsler, Rafael Allan

    2016-01-01

    Background Infectious crystalline keratopathy is a rare, progressive infection characterized by the insidious progression of branches and crystalline corneal opacities with minimal or no inflammation. This case report describes the evolution of an infectious crystalline keratopathy caused by Cladosporium sp., which developed after tectonic keratoplasty in a patient with a history of ocular trauma. Case presentation A 40-year-old Brazilian male was the victim of firework-induced trauma to the left eye, which resulted in a corneal laceration that could not be sutured as well as a severe traumatic cataract. The patient underwent penetrating keratoplasty and phacoemulsification. During postoperative follow-up, another therapeutic keratoplasty was required because unresponsive infectious keratitis was observed. The infiltrate’s characteristics were suggestive of infectious crystalline keratopathy; in particular, the infiltrate was insidious and progressive, and grayish-white branches appeared in the anterior corneal stroma. As different therapies were administered, inflammatory reactions ranging from mild to severe were observed. The infection was unresponsive to typical antifungal drugs. This lack of response most likely occurred due to steroid treatment and the diffuse corneal spread of an atypical microorganism, which was subsequently identified in culture as Cladosporium sp. After the second therapeutic keratoplasty, the patient’s eye integrity was successfully reestablished. Conclusion This study likely provides the first report describing a case of infectious crystalline keratopathy caused by Cladosporium sp. This case emphasizes the clinical characteristics and outcome of this type of keratitis. PMID:27621671

  18. Penetrating keratoplasty restoring vision in an unusual case of corneal opacity following exposure to Euphorbia latex.

    PubMed

    Dutta, Jayanta; Choudhury, Somnath; Lahiri, Kapildeb; Savale, Smruti; Banerjee, Monideepa; Datta, Himadri

    2015-10-01

    The milky sap of the Euphorbia plant is highly toxic and causes inflammation to the skin and eyes. Damage to the eye ranges from superficial epithelial defects, keratoconjunctivitis, mild to moderate corneal edema, anterior uveitis, Descemet membrane folds, raised intraocular pressure and rarely corneal opacity in severe untreated cases. Here we report a case of visual restoration by optical penetrating keratoplasty in a patient with severe corneal opacity following exposure to Euphorbia latex. PMID:25540165

  19. Laser welding in penetrating keratoplasty and cataract surgery of pediatric patients: early results

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Pini, Roberto; Menabuoni, Luca; Malandrini, Alex; Canovetti, Annalisa; Lenzetti, Ivo; Capozzi, Paolo; Valente, Paola; Buzzonetti, Luca

    2013-03-01

    Diode laser welding of ocular tissues is a procedure that enables minimally invasive closure of a corneal wound. This procedure is based on a photothermal effect: a water solution of Indocyanine Green (ICG) is inserted in the surgical wound, in order to stain the corneal tissue walls. The stained tissue is then irradiated with a low power infrared diode laser, delivering laser light through a 300-μm core diameter optical fiber. This procedure enables an immediate closure of the wounds: it is thus possible to reduce or to substitute the use of surgical threads. This is of particular interest in children, because the immediate closure improves refractive outcome and anti-amblyopic effect; moreover this procedure avoids several general anaesthesia for suture management. In this work, we present the first use of diode laser welding procedure in paediatric patients. 5 selected patients underwent cataract surgery (Group 1), while 4 underwent fs-laserassisted penetrating keratoplasty (Group 2). In Group 1 the conventional surgery procedure was performed, while no stitches were used for the closure of the surgical wounds: these were laser welded and immediately closed. In Group 2 the donor button was sutured upon the recipient by 8 single stitches, instead of 16 single stitches or a running suture. The laser welding procedure was performed in order to join the donor tissue to the recipient bed. Objective observations in the follow up study evidenced a perfect adhesion of the laser welded tissues, no collateral effects and an optimal restoration of the treated tissues.

  20. Efficacy and Safety of Deep Anterior Lamellar Keratoplasty vs. Penetrating Keratoplasty for Keratoconus: A Meta-Analysis

    PubMed Central

    Liu, Hao; Chen, Yihui; Wang, Peng; Li, Bing; Wang, Weifang; Su, Yan; Sheng, Minjie

    2015-01-01

    Purpose To evaluate difference in therapeutic outcomes between deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) for the clinical treatment of keratoconus. Methods A comprehensive search was conducted in Pubmed, EMBASE, Cochrane Library, and Web of science. Eligible studies should include at least one of the following factors: best corrected visual acuity (BCVA), postoperative spherical equivalent (SE), postoperative astigmatism and endothelial cell count (ECC), central corneal thickness (CCT), graft rejection and graft failure, of which BCVA, graft rejection and graft failure were used as the primary outcome measures, and postoperative SE, astigmatism, CCT and ECC as the secondary outcome measures. Given the lack of randomized clinical trials (RCTs), cohort studies and prospective studies were considered eligible. Results Sixteen clinical trials involving 6625 eyes were included in this review, including 1185 eyes in DALK group, and 5440 eyes in PKP group. The outcomes were analyzed using Cochrane Review Manager (RevMan) version 5.0 software. The postoperative BCVA in DALK group was significantly better than that in PKP group (OR = 0.48; 95%CI 0.39 to 0.60; p<0.001). There were fewer cases of graft rejection in DALK group than those in PKP group (OR = 0.28; 95%CI 0.15 to 0.50; p<0.001). Nevertheless the rate of graft failure was similar between DALK and PKP groups (OR = 1.05; 95%CI 0.81 to 1.36; p = 0.73). There were no significant differences in the secondary outcomes of SE (p = 0.70), astigmatism (p = 0.14) and CCT (p = 0.58) between DALK and PKP groups. And ECC in DALK group was significantly higher than PKP group (p<0.001). The postoperative complications, high intraocular pressure (high-IOP) and cataract were analyzed, fewer cases of complications occurred in DALK group than those in PKP group (high-IOP, OR 0.22, 95% CI 0.11–0.44, P<0.001) (cataract, OR 0.22; 95% CI 0.08–0.61, P = 0.004). And no cases of expulsive hemorrhage

  1. Iris-claw, retropupillary-fixated, aphakic intraocular lens implantation for traumatic aphakia following penetrating keratoplasty

    PubMed Central

    Anbari, Anas A.

    2015-01-01

    Summary We report the correction of aphakia using an iris-claw, aphakic intraocular lens (IOL) fixated in a retropupillary location in a 17-year-old young man who suffered blunt trauma to his eye 5 months after penetrating keratoplasty (PKP). There were no intraoperative complications. At 21 months after implantation, the patient’s uncorrected distance visual acuity was 20/28; his corrected distance visual acuity was 20/22, with +0.50 −3.00 × 155. Intraocular pressure was normal, and endothelial cell count was 1798 cells/mm2.

  2. Excimer versus Femtosecond Laser Assisted Penetrating Keratoplasty in Keratoconus and Fuchs Dystrophy: Intraoperative Pitfalls

    PubMed Central

    El-Husseiny, Moatasem; Seitz, Berthold; Langenbucher, Achim; Akhmedova, Elena; Szentmary, Nora; Hager, Tobias; Tsintarakis, Themistoklis; Janunts, Edgar

    2015-01-01

    Purpose. To assess the intraoperative results comparing two non-mechanical laser assisted penetrating keratoplasty approaches in keratoconus and Fuchs dystrophy. Patients and Methods. 68 patients (age 18 to 87 years) with keratoconus or Fuchs dystrophy were randomly distributed to 4 groups. 35 eyes with keratoconus and 33 eyes with Fuchs dystrophy were treated with either excimer laser ([Exc] groups I and II) or femtosecond laser-assisted ([FLAK] groups III and IV) penetrating keratoplasty. Main intraoperative outcome measures included intraoperative decentration, need for additional interrupted sutures, alignment of orientation markers, and intraocular positive pressure (vis a tergo). Results. Intraoperative recipient decentration occurred in 4 eyes of groups III/IV but in none of groups I/II. Additional interrupted sutures were not necessary in groups I/II but in 5 eyes of groups III/IV. Orientation markers were all aligned in groups I/II but were partly misaligned in 8 eyes of groups III/IV. Intraocular positive pressure grade was recognized in 12 eyes of groups I/II and in 19 eyes of groups III/IV. In particular, in group III, severe vis a tergo occurred in 8 eyes. Conclusions. Intraoperative decentration, misalignment of the donor in the recipient bed, and need for additional interrupted sutures as well as high percentage of severe intraocular positive pressure were predominantly present in the femtosecond laser in keratoconus eyes. PMID:26483974

  3. Clinical outcomes of trabeculectomy vs. Ahmed glaucoma valve implantation in patients with penetrating keratoplasty : (Trabeculectomy vs. Ahmed galucoma valve in patients with penetrating keratoplasty).

    PubMed

    Akdemir, Mehmet Orcun; Acar, Banu Torun; Kokturk, Furuzan; Acar, Suphi

    2016-08-01

    The aim of this study was to compare the visual outcomes, intraocular pressure (IOP), and endothelial cell loss caused by trabeculectomy (TRAB) and Ahmed glaucoma valve (AGV) implantation in patients who had previously undergone penetrating keratoplasty (PKP). The data from all patients who underwent surgical treatment of glaucoma after PKP were reviewed at the Cornea Department of Haydarpasa Numune Education and Research Hospital. Eighteen patients who had undergone surgical treatment of glaucoma after PKP were included in this retrospective study. Time between PKP and glaucoma surgeries, visual acuity results, IOP results, endothelial cell counts (ECC) before the surgery, at 1st, 6th, and 12th month of surgery were recorded. Differences between two groups were evaluated. Mean loss of ECC was 315 cells/mm(2) in the AGV group and 197 cells/mm(2) in TRAB group at 12th month of glaucoma surgery. The difference between endothelial cell loss at 12th month of surgery was statistically significant and higher in AGV group (p < 0.001). The decrease in IOP was 64.2 % in AGV group and 46.9 % in TRAB group at 12th month of surgery. Both differences were statistically significant between 2 groups (p = 0.001, 0.001). TRAB successfully decreased both the IOP and endothelial cell loss in patients with post-PKP glaucoma. Ahmed glaucoma valve had a significantly better IOP lowering but higher endothelial cell loss effect. PMID:26646776

  4. Penetrating keratoplasty for treatment of corneal protrusion in a great horned owl (Bubo virginianus).

    PubMed

    Andrew, Stacy E; Clippinger, Tracy L; Brooks, Dennis E; Helmick, Kelly E

    2002-09-01

    A young adult great horned owl (Bubo virginianus) was examined following presumed trauma. The owl had soft tissue injury to its left wing as well as corneal protrusion, lens subluxation, and iridodialysis of the right eye. The bird's eye was treated surgically with a large, rectangular penetrating keratoplasty. Following escape from housing, the bird was found with partial wound dehiscence and iris prolapse 12 days post operation. Surgical repair was performed and healing progressed for 14 days, at which time the transplant dehisced and the globe was exenterated. The patient rehabilitated well until escaping from its cage again 4 weeks later, at which time it sustained an open comminuted humeral fracture and was euthanized. PMID:12236872

  5. Quantification of Collagen Ultrastructure after Penetrating Keratoplasty – Implications for Corneal Biomechanics

    PubMed Central

    Gardner, Steven J.; Kamma-Lorger, Christina S.; Hayes, Sally; Nielsen, Kim; Hjortdal, Jesper; Sorensen, Thomas; Terrill, Nicholas J.; Meek, Keith M.

    2013-01-01

    Purpose To quantify long-term changes in stromal collagen ultrastructure following penetrating keratoplasty (PK), and evaluate their possible implications for corneal biomechanics. Methods A pair of 16 mm post-mortem corneo-scleral buttons was obtained from a patient receiving bilateral penetrating keratoplasty 12 (left)/28 (right) years previously. Small-angle x-ray scattering quantified collagen fibril spacing, diameter and spatial order at 0.5 mm or 0.25 mm intervals along linear scans across the graft margin. Corresponding control data was collected from two corneo-scleral buttons with no history of refractive surgery. Wide-angle x-ray scattering quantified collagen fibril orientation at 0.25 mm (horizontal)×0.25 mm (vertical) intervals across both PK specimens. Quantification of orientation changes in the graft margin were verified by equivalent analysis of data from a 13 year post-operative right PK specimen obtained from a second patient in a previous study, and comparison made with new and published data from normal corneas. Results Marked changes to normal fibril alignment, in favour of tangentially oriented collagen, were observed around the entire graft margin in all PK specimens. The total number of meridional fibrils in the wound margin was observed to decrease by up to 40%, with the number of tangentially oriented fibrils increasing by up to 46%. As a result, in some locations the number of fibrils aligned parallel to the wound outnumbered those spanning it by up to five times. Localised increases in fibril spacing and diameter, with an accompanying reduction in matrix order, were also evident. Conclusions Abnormal collagen fibril size and spatial order within the PK graft margin are indicative of incomplete stromal wound remodelling and the long term persistence of fibrotic scar tissue. Lasting changes in collagen fibril orientation in and around PK wounds may alter corneal biomechanics and compromise the integrity of the graft-host interface in the

  6. Penetrating keratoplasty using femtosecond laser-enabled keratoplasty with zig-zag incisions versus a mechanical trephine in patients with keratoconus

    PubMed Central

    Gaster, Ronald N; Dumitrascu, Oanna; Rabinowitz, Yaron S

    2013-01-01

    Background/aims This paper will compare the visual outcomes of two different penetrating keratoplasty (PKP) techniques in patients with keratoconus. It is a retrospective comparative surgical case series of 116 keratoconus patients (137 eyes) who had PKP at the Cornea Eye Institute, Beverly Hills, California, USA. Methods 56 keratoconus patients (66 eyes) underwent femtosecond laser-enabled keratoplasty (FLEK) with a zig-zag incision configuration. Their visual parameters were compared with those of 60 patients (71 eyes) who had traditional blade mechanical trephination PKP. The range of follow-up was between 3 and 6 months. The main outcome measures included uncorrected visual acuity and best spectacle-corrected visual acuity (BSCVA), manifest refractive spherical equivalent and topographically determined astigmatism. Results BSCVA was significantly better as early as 3 months postoperatively (p=0.001) in the FLEK group. Visual recovery to 20/40 after 3 months was significantly better in the FLEK group (p<0.001). Topographic astigmatism was lower in the FLEK group, but the difference between the two groups reached significance only at 3 months of follow-up (p=0.001). Postoperative complications noted were not different between the two groups. Conclusions Faster visual recovery and better long-term outcomes were observed in keratoconus patients who had FLEK compared with those who had the mechanical PKP procedure with 6 months of postoperative follow-up. PMID:22790433

  7. Endothelial Cell Density to Predict Endothelial Graft Failure After Penetrating Keratoplasty

    PubMed Central

    Lass, Jonathan H.; Sugar, Alan; Benetz, Beth Ann; Beck, Roy W.; Dontchev, Mariya; Gal, Robin L.; Kollman, Craig; Gross, Robert; Heck, Ellen; Holland, Edward J.; Mannis, Mark J.; Raber, Irving; Stark, Walter; Stulting, R. Doyle

    2010-01-01

    Objective To determine whether preoperative and/or postoperative central endothelial cell density (ECD) and its rate of decline postoperatively are predictive of graft failure caused by endothelial decompensation following penetrating keratoplasty to treat a moderate-risk condition, principally, Fuchs dystrophy or pseudophakic corneal edema. Methods In a subset of Cornea Donor Study participants, a central reading center determined preoperative and postoperative ECD from available specular images for 17 grafts that failed because of endothelial decompensation and 483 grafts that did not fail. Results Preoperative ECD was not predictive of graft failure caused by endothelial decompensation (P = .91). However, the 6-month ECD was predictive of subsequent failure (P < .001). Among those that had not failed within the first 6 months, the 5-year cumulative incidence (±95% confidence interval) of failure was 13% (±12%) for the 33 participants with a 6-month ECD of less than 1700 cells/mm2 vs 2%(±3%) for the 137 participants with a 6-monthECDof 2500 cells/mm2 or higher. After 5 years’ follow-up, 40 of 277 participants (14%) with a clear graft had an ECD below 500 cells/mm2. Conclusions Preoperative ECD is unrelated to graft failure from endothelial decompensation, whereas there is a strong correlation of ECD at 6 months with graft failure from endothelial decompensation. A graft can remain clear after 5 years even when the ECD is below 500 cells/mm2. PMID:20065219

  8. Abiotrophia defectiva causing infectious crystalline keratopathy and corneal ulcer after penetrating keratoplasty: a case report

    PubMed Central

    2013-01-01

    Background Infectious crystalline keratopathy is commonly caused by Streptococcus viridans and other gram positive organisms. We present the first case of infectious crystalline keratopathy that developed into a corneal ulcer and grew Abiotrophia defectiva which responded well to topical and systemic antimicrobial therapy and did not require re-grafting. A 78-year-old man underwent penetrating keratoplasty for pseudophakic bullous keratopathy. He presented 1.5 years later with infectious crystalline keratopathy which progressed to a corneal ulcer. The patient received topical fortified vancomycin and moxifloxacin, as well as oral moxifloxacin. Findings The corneal ulcer base was cultured and grew A. defectiva, or nutritionally deficient streptococcus. Complete resolution of the corneal infiltrates was obtained within three months. Conclusions Nutritionally deficient streptococcus has been implicated in numerous human diseases, including endocarditis, and is increasingly being recognized as an important pathogen. This represents the second reported case of A. defectiva causing infectious crystalline keratopathy in humans and the first case of A. defectiva successfully treated with antibiotics. This case shows that aggressive antibiotic therapy can be effective in A. defectiva-associated infectious crystalline keratopathy. PMID:23514629

  9. Laser Scanning In Vivo Confocal Microscopy of Clear Grafts after Penetrating Keratoplasty

    PubMed Central

    Wang, Dai; Song, Peng; Wang, Shuting; Sun, Dapeng; Wang, Yuexin; Zhang, Yangyang

    2016-01-01

    Purpose. To evaluate the changes of keratocytes and dendritic cells in the central clear graft by laser scanning in vivo confocal microscopy after penetrating keratoplasty (PK). Methods. Thirty adult subjects receiving PK at Shandong Eye Institute and with clear grafts and no sign of immune rejection after surgery were recruited into this study, and 10 healthy adults were controls. The keratocytes and dendritic cells in the central graft were evaluated by laser scanning confocal microscopy, as well as epithelium cells, keratocytes, corneal endothelium cells, and corneal nerves (especially subepithelial plexus nerves). Results. Median density of subepithelial plexus nerves, keratocyte density in each layer of the stroma, and density of corneal endothelium cells were all lower in clear grafts than in controls. The dendritic cells of five (16.7%) patients were active in Bowman's membrane and stromal membrane of the graft after PK. Conclusions. Activated dendritic cells and Langerhans cells could be detected in some of the clear grafts, which indicated that the subclinical stress of immune reaction took part in the chronic injury of the clear graft after PK, even when there was no clinical rejection episode. PMID:27034940

  10. Customized photorefractive keratectomy to correct high ametropia after penetrating keratoplasty: A pilot study

    PubMed Central

    De Rosa, Giuseppe; Boccia, Rosa; Santamaria, Carmine; Fabbozzi, Lorenzo; De Rosa, Luigi; Lanza, Michele

    2014-01-01

    Purpose To evaluate preliminarily the safety and efficacy of customized photorefractive keratectomy (PRK) to correct ametropia and irregular astigmatism after penetrating keratoplasty (PK). Methods This pilot study included five eyes of five patients with a mean spherical equivalent of −5.1 ± 1.46 D (range from −2.75 to −6.50 D). In all cases, ametropia and irregular astigmatism was corrected with topography-guided customized PRK. Ocular examinations with topographic analysis were performed preoperatively as well as at 1, 3 and 6 months after surgery. Results All eyes gained postoperatively at least three Snellen lines of uncorrected visual acuity. Mean refractive spherical equivalent was 0.62 ± 0.63 D (range from −0.25 to −1.75 D) at 6 months postoperatively. Conclusion Our pilot study suggests that customized PRK can be a safe and effective method for treating ametropia and irregular astigmatisms after PK. Future studies with larger samples and longer follow-ups should be performed to confirm these results. PMID:25151176

  11. Intraocular pressure measurement after penetrating keratoplasty: minified Goldmann applanation tonometer, pneumatonometer, and Tono-Pen versus manometry.

    PubMed Central

    Ménage, M J; Kaufman, P L; Croft, M A; Landay, S P

    1994-01-01

    The accuracy of intraocular pressure measurement with the minified Goldmann applanation tonometer, the pneumatonometer, and the Tono-Pen tonometer were compared in post-mortem human eyes which had undergone penetrating keratoplasty. Enucleated post-mortem human eyes underwent same sized (7.75 mm) or 0.5 mm oversized (8.25 mm) autologous penetrating keratoplasty. Intraocular pressure was then set and measured manometrically while being determined successively with each tonometer over the range of 0-65 mm Hg. Linear regression analysis comparing tonometric and manometric readings showed: (1) minified Goldmann applanation tonometer-slope 0.985 and 0.944, intercept 1.64 and 2.55 mm Hg, correlation coefficient 0.99 and 0.99 in same sized and oversized grafted eyes respectively; (2) pneumatonometer-slope 1.008 and 0.990, intercept 3.37 and 3.69 mm Hg, correlation coefficient 0.99 and 0.98; (3) Tono-Pen-slope 1.061 and 1.002, intercept 5.01 and 4.06 mm Hg, correlation coefficient 0.97 and 0.98. We concluded that the minified Goldmann applanation tonometer is as accurate or more accurate than the pneumatonometer and the Tono-Pen in post-mortem post-keratoplasty human eyes, and may be an economical, convenient alternative to the latter two instruments in clinical practice. PMID:7947545

  12. Trends in penetrating keratoplasty in the United States 1980-2005.

    PubMed

    Ghosheh, Faris R; Cremona, Federico A; Rapuano, Christopher J; Cohen, Elisabeth J; Ayres, Brandon D; Hammersmith, Kristin M; Raber, Irving M; Laibson, Peter R

    2008-06-01

    In this review, we analyze the trends in corneal transplantation over the past 25 years in the United States. The most dramatic change was the progressive sharp increase in the number of corneal transplants performed during the 1980s, corresponding with the rise of pseudophakic bullous keratopathy (PBK) as the leading indication for keratoplasty. More recently, there has been a steady annual decline in total keratoplasties for more than a decade, corresponding with a decline in the cases performed for PBK, which still accounts for the highest percentage of cases done. Regrafts have been an increasingly important indication for keratoplasty, as older grafts fail. Keratoconus, Fuchs dystrophy, and other inherited diseases have remained consistent indications for keratoplasty during the last quarter century. PMID:18084724

  13. Comparison the post operative refractive errors in same size corneal transplantation through deep lamellar keratoplasty and penetrating keratoplasty methods after sutures removing in keratoconus patients

    PubMed Central

    Razmjoo, Hasan; Ghoreishi, Seyed Mohammad; Ashtari, Alireza; Ghafouri, Iman; Mamousi, Bashir

    2016-01-01

    Background: Corneal transplantation is a surgery in which cornea is replaced by a donated one and can be completely penetrating keratoplasty (PK) or included a part of cornea deep lamellar keratoplasty (DLK). Although the functional results are limited by some complications, it is considered as one of the most successful surgeries. This study aimed to compare the refractive errors after same size corneal transplantation through DLK and PK methods in keratoconus patients over 20 years. Materials and Methods: This descriptive, analytical study was conducted in Feiz Hospital, Sadra and Persian Clinics of Isfahan in 2013–2014. In this study, 35 patients underwent corneal transplantation by PK and 35 patients by DLK, after removing the sutures, the patients were compared in terms of best corrected visual acuity (BCVA) and refractive errors. Data were analyzed using Chi-square and t Student tests by SPSS software. Results: The BCVA mean in DLK and PK groups was 6/10 ± 2/10 and 5/10 ± 2/10, respectively, with no significant difference (P = 0.4). The results showed 9 cases of DLK and 6 cases of PK had normal (8/10 ≤ BCVA) visual acuity (25.7% vs. 17.1%), 24 cases of DLK and 27 cases of PK had mild vision impairment (68.6% vs. 77.1%) and 2 cases of the DLK group and 2 cases of PK had moderate vision impairment, (5.7% vs. 5.7%), there was no significant difference in “BCVA” (P = 0.83). Conclusions: Both methods were acceptably effective in improving BCVA, but according to previous articles (5,9,10) the DLK method due to fewer complications and less risk of rejection was superior to another method and in the absence of any prohibition this method is recommended. PMID:27099852

  14. Safety of prophylactic intracameral moxifloxacin ophthalmic solution after cataract surgery in patients with penetrating keratoplasty

    PubMed Central

    Arslan, Osman Sevki; Arici, Ceyhun; Unal, Mustafa; Cicik, Erdogan; Mangan, Mehmet Serhat; Atalay, Eray

    2014-01-01

    AIM To determine the safety of prophylactic intracameral moxifloxacin after cataract surgery in patients with penetrating keratoplasty (PKP). METHODS In this retrospective study of consecutive patients who had phacoemulsification cataract surgery after PKP, were treated with intracameral moxifloxacin 0.5% ophthalmic solution (0.5 mg/0.1 mL). The main outcome measures were anterior chamber reaction, best corrected visual acuity (BCVA), corneal endothelial cell count (ECC), and central corneal thickness (CCT). RESULTS Fifty-five patients were recruited (26 males, 29 females). The mean age was 54.36±4.97y (range 45-64y). All eyes had improved postoperative BCVA. The mean BCVA was 0.25 preoperatively and 0.57 postoperatively, which was statistically significant (P<0.001). One eye had 3+, 7 eyes had 2+, 12 eyes had 1+ and 8 eyes had trace amount of aqueous cells on the first day after surgery. All eyes had no anterior chamber cells at subsequent follow up examinations. Effective phacoemulsification time was 4.33±1.01s. The mean ECC was 2340.20 cells/mm2 preoperatively and 1948.75 cells/mm2 1mo postoperatively (P<0.001). The increase of 21.09 µm in postoperative pachymetry 1mo after surgery was statistically significant (P<0.001). CONCLUSION No untoward effects were observed after intracameral injection of moxifloxacin (0.5 mg/0.1 mL) in terms of anterior chamber reaction, CCT, ECC, and visual rehabilitation at the conclusion of cataract surgery in patients with PKP. PMID:25349795

  15. Corneal Graft Rejection Ten Years after Penetrating Keratoplasty in the Cornea Donor Study

    PubMed Central

    Dunn, Steven P.; Gal, Robin L.; Kollman, Craig; Raghinaru, Dan; Dontchev, Mariya; Blanton, Christopher L.; Holland, Edward J; Lass, Jonathan H.; Kenyon, Kenneth R.; Mannis, Mark J; Mian, Shahzad I.; Rapuano, Christopher J.; Stark, Walter J.; Beck, Roy W.

    2015-01-01

    Purpose To assess the effect of donor and recipient factors on corneal allograft rejection and evaluate whether a rejection event was associated with graft failure. Methods 1,090 subjects undergoing penetrating keratoplasty for a moderate risk condition (principally Fuchs’ dystrophy or pseudophakic corneal edema) were followed for up to 12 years. Associations of baseline recipient and donor factors with the occurrence of a rejection event were assessed in univariate and multivariate proportional hazards models. Results Among 651 eyes with a surviving graft at 5 years, the 10-year graft failure (± 99% CI) rates were 12% ± 4% among eyes with no rejection events in the first 5 years, 17% ± 12% in eyes with at least one probable, but no definite rejection event, and 22% ± 20% in eyes with at least one definite rejection event. The only baseline factor significantly associated with a higher risk of definite graft rejection was a preoperative history of glaucoma, particularly when prior glaucoma surgery had been performed and glaucoma medications were being used at time of transplant (10-year incidence 35% ± 23% compared with 14% ± 4% in eyes with no history of glaucoma/intraocular pressure treatment, p=0.008). Conclusion Those patients who experienced a definite rejection event frequently went on to graft failure raising important questions as to how we might change acute and long-term corneal graft management. Multivariate analysis indicated that the prior use of glaucoma medications and glaucoma filtering surgery was a significant risk factor related to a definite rejection event. PMID:25119961

  16. Effect of Donor Graft Quality on Clinical Outcomes After Penetrating Keratoplasty for Keratoconus

    PubMed Central

    Feizi, Sepehr; Javadi, Mohammad Ali; Ghasemi, Hassan; Javadi, Fatemeh

    2015-01-01

    Purpose: To evaluate the effect of donor and eye bank characteristics on graft rating and clinical outcomes after penetrating keratoplasty (PK) for keratoconus. Methods: This retrospective interventional case series included 252 keratoconic eyes which underwent PK. Donor data included age and sex, cause of death, death-to-preservation time, preservation-to-surgery time, epithelial and stromal status, endothelial cell density (ECD) and morphology, and graft rating. Postoperative outcomes included visual acuity, refractive error, epithelial problems, suture-related complications, graft rejection, and graft transparency. Multivariate regression analysis assessed correlations between donor and eye bank characteristics and graft quality, and postoperative outcomes. Results: Mean recipient and donor age was 29.7 ± 10.0 and 26.2 ± 8.8 years, respectively and mean follow-up period was 66.7 ± 38.5 months. Death-to-preservation time was significantly associated with the presence of graft epithelial sloughing (P = 0.005) and stromal cloudiness (P < 0.001). Donor age significantly influenced ECD (P = 0.02), mean cell area (P = 0.04), and hexagonality (P = 0.01). The presence of epithelial defects on postoperative day 1 correlated significantly with death-to-preservation time (P = 0.004). Graft stromal edema on postoperative day 1 was significantly associated with graft epithelial sloughing (P < 0.001). Postoperative visual and refractive outcomes, complications, and graft survival were not correlated with any donor or eye bank factors. Conclusion: Donor and eye bank variables affected the quality of donor corneas and early postoperative course. However, their long term effect on clinical outcomes, complications, and graft survival were insignificant. PMID:27051479

  17. Trans-scleral diode laser cyclophotocoagulation for refractory glaucoma after high-risk penetrating keratoplasty.

    PubMed

    Rodríguez-García, Alejandro; González-González, Luis Alonso; Carlos Alvarez-Guzmán, J

    2016-06-01

    To analyze the intraocular pressure reduction, number of anti-glaucoma medications needed, and post-operative complications of trans-scleral diode laser cyclophotocoagulation (DCPC) in patients with high-risk penetrating keratoplasty (PKP) and secondary refractory glaucoma. Prospective interventional, longitudinal, non-comparative series of cases, including 16 eyes of 15 patient's post-PKP on maximal anti-glaucoma medical therapy with intraocular pressures above 22 mmHg. All patients received 18 shots, 360° peri-limbal (avoiding the long posterior ciliary nerves and arteries at 3 and 9 o'clock positions) of trans-scleral DCPC (2000 mW, time: 2.0 s/shot). There was a 55.5 % reduction (total of 14.0 mmHg) of the mean pre-operative IOP (31.5 mmHg) after the first diode laser application (p = 0.0020). Re-treatment was required in 31.2 % of eyes over a mean period of 10.7 months. In these five eyes, the mean pre-operative IOP was 40.4 mmHg, which decreased to 15.0 mmHg post-therapy, and a mean IOP reduction of 25.4 mmHg (p = 0.0218). There was a 51.0 % reduction in the mean number of medications used after the first, and a 57.1 % reduction after a second laser application. The incidence of failure (IOP ≥ 22 mmHg or need of additional medical therapy) from initial intervention to loss of follow-up was 1.3 % per person-month. DCPC effectively reduces the intraocular pressure and the number of anti-glaucoma medications with few complications in patients after high-risk PKP and secondary glaucoma. Only, one-third of the eyes needed a second intervention to control the intraocular pressure. Post-DCPC complications were limited to phthisis bulbi and endothelial dysfunction, one eye each. Please check and confirm the author names and initials are correct. Also, kindly confirm the details in the metadata are correct. PMID:26419547

  18. Quantitative & qualitative analysis of endothelial cells of donor cornea before & after penetrating keratoplasty in different pathological conditions

    PubMed Central

    Gupta, Aruna K.R.; Gupta, Roopam K.R.

    2016-01-01

    Background & objectives: Endothelial cells of the donor cornea are known to be affected quantitatively and qualitatively in different pathological conditions after penetrating keratoplasty (PK) and this has direct effect on the clarity of vision obtained after PK. This study was undertaken to analyze the qualitative and quantitative changes in donor endothelial cells before and after PK in different pathological conditions. Methods: A prospective investigational analysis of 100 consecutive donor corneas used for penetrating keratoplasty between June 2006 and June 2008, was conducted. The patients were evaluated on the first day, at the end of first week, first month, third and six months and one year. Results: A decrease was observed in endothelial cell count in all pathological conditions. After one year of follow up the loss was 33.1 per cent in corneal opacity, 45.9 per cent in acute infective keratitis (AIK), 58.5 per cent in regrafts, 28.5 per cent in pseudophakic bullous keratopathy (PBK), 37 per cent in descemetocele, 27 per cent in keratoconus and 35.5 per cent in aphakic bullous keratopathy (ABK) cases. Interpretation & conclusions: The endothelial cell loss was highest in regraft cases which was significant (P<0.05), while the least endothelial cell loss was seen in keratoconus cases. The cell loss was associated with increase in coefficient of variation (CV), i.e. polymegathism and pleomorphism. Inspite of this polymegathism and pleomorphism, the clarity of the graft was maintained. PMID:27121519

  19. Clinical presentation, risk factors and treatment outcomes of first allograft rejection after penetrating keratoplasty in early and late postoperative period

    PubMed Central

    Perera, C; Jhanji, V; Lamoureux, E; Pollock, G; Favilla, I; Vajpayee, R B

    2012-01-01

    Purpose Corneal graft rejection is the most common reason for the failure of an allograft corneal transplant. We undertook this study to identify and compare risk factors and treatment outcomes for early and late corneal graft rejections after optical penetrating keratoplasty. Methods A retrospective case file analysis of 880 primary penetrating keratoplasties was performed at a tertiary ophthalmic care centre. Patients were divided into early rejectors (rejection episode within 6 months postoperatively) and late rejectors (rejection episode after 6 months postoperatively). Main parameters evaluated were demographics, preoperative diagnosis and clinical signs, donor tissue details, surgical technique, details of rejection episode, treatment, and outcome information. Results A total of 156 patients with rejection episodes were identified. Of these, 42 (26.9%) patients experienced early rejection episodes and 114 (73.1%) patients experienced late rejection episodes. Preoperative donor and recipient characteristics, surgical technique, and clinical presentation of graft rejection were found to be similar between both groups after a Bonferroni correction was applied (P>0.005). Treatment outcomes of graft rejections were not significantly different (P=0.46) between early and late rejectors, with 83% of patients responding to rejection treatment (80% early rejectors; 85% late rejectors). Conclusion Patients with early and late graft rejection have similar characteristics and both groups respond to treatment equally. PMID:22344190

  20. Outcome of therapeutic penetrating keratoplasty in a tertiary eye care center in Nepal

    PubMed Central

    Bajracharya, Leena; Gurung, Reeta

    2015-01-01

    Background Corneal ulcer is an important cause of blindness in developing countries. Therapeutic keratoplasty for infective keratitis is a frequently performed surgery in these countries. Objective To find out the outcome of therapeutic keratoplasty for infective keratitis. Methods Records of 5 years were reviewed of patients who underwent therapeutic keratoplasty from 2006 to 2010. Data collected included demographic parameters, indications for surgery, microbiology of the ulcers, type of surgery performed, and donor tissue details. In the follow-up period, ocular status was evaluated in terms of eradication of disease, anatomic success, graft clarity, visual acuity, and development of glaucoma and cataract. Results In all, 180 eyes of 180 patients were enrolled in the study; 59.4% of the patients were male. Average age was 44.4±16.7 years. Overall, 71% of infective keratitis was perforated. A total of 101 (56%) eyes were positive for organisms of which 49 showed pure fungus and 49 showed pure bacteria. The commonest fungus and bacteria isolated were Aspergillus and Streptococcus, respectively. Average follow-up period was 29±23 months. Overall cure rate of infection was 88.8%, anatomical success rate was 89.5%, and graft clarity was 37.2%. Overall, 43.4% had secondary glaucoma. In the postoperative course, 65.8% of phakic eyes had developed cataract. In all, 38.6% of graft had endothelial failure and 24% of the graft failed due to late infective keratitis. Overall functional success with a visual acuity above 6/60 was 25.4%. Bacterial keratitis had a significantly higher cure rate, anatomical success, and graft clarity compared to fungal keratitis. Conclusion Therapeutic keratoplasty is an important procedure to save the eye and preserve vision in severe infective keratitis. There is a high incidence of postoperative glaucoma, cataract, and graft failure in such a surgery. Bacterial keratitis has a better outcome than fungal keratitis. PMID:26673279

  1. The Effect of Donor Diabetes History on Graft Failure and Endothelial Cell Density Ten Years after Penetrating Keratoplasty

    PubMed Central

    Lass, Jonathan H.; Riddlesworth, Tonya D.; Gal, Robin L.; Kollman, Craig; Benetz, Beth A.; Price, Francis W.; Sugar, Alan; Terry, Mark A.; Soper, Mark; Beck, Roy W.

    2014-01-01

    Objective To examine the long term effect of donor diabetes history on graft failure and endothelial cell density (ECD) after penetrating keratoplasty (PKP) in the Cornea Donor Study Design Multi-center prospective, double-masked, controlled clinical trial Participants 1090 subjects undergoing PKP for a moderate risk condition, principally Fuchs’ dystrophy or pseudophakic/aphakic corneal edema (PACE), were enrolled by 105 surgeons from 80 clinical sites in the United States. Methods Corneas from donors 12 to 75 years old were assigned by 43 eye banks to participants without respect to recipient factors. Donor and recipient diabetes status was determined from existing medical records. Images of the central endothelium were obtained preoperatively (baseline) and at intervals for ten years postoperatively and analyzed by a central image analysis reading center to determine ECD. Main Outcome Measure(s) Time to graft failure (regraft or cloudy cornea for 3 consecutive months) and ECD. Results There was no statistically significant association of donor diabetes history with 10-year graft failure, baseline ECD, 10-year ECD or ECD values longitudinally over time in unadjusted analyses nor after adjusting for donor age and other significant covariates. The 10-year graft failure rate was 23% in the 199 cases receiving a cornea from a donor with diabetes versus 26% in the 891 cases receiving a cornea from a donor without diabetes (95% confidence interval for the difference: −10% to +6%; unadjusted p = 0.60). Baseline ECD (p=0.71), 10-year ECD (p>0.99), and changes in ECD over 10 years (p=0.86) were similar comparing donor diabetes and no-diabetes groups. Conclusions and Relevance The study results do not suggest an association between donor diabetes and PKP outcome. However, the assessment of donor diabetes was imprecise and based on historical data only. The increasing frequency of diabetes in the aging population in the United States affects the donor pool, thus the

  2. Keratoplasty postoperative treatment update.

    PubMed

    Shimmura-Tomita, Machiko; Shimmura, Shigeto; Satake, Yoshiyuki; Shimazaki-Den, Seika; Omoto, Masahiro; Tsubota, Kazuo; Shimazaki, Jun

    2013-11-01

    Immunosuppressive therapy is the main postoperative treatment for keratoplasty, but there are considerable differences in protocols for the use of steroids and other immunosuppressants. Therefore, we conducted 2 prospective randomized clinical trials and 1 prospective nonrandomized clinical trial on keratoplasty postoperative treatment. One study evaluated the efficacy and safety of long-term topical corticosteroids after a penetrating keratoplasty was performed. Patients who underwent keratoplasty and maintained graft clarity for >1 year were randomly assigned to either a steroid or a no-steroid group. At the 12-month follow-up, the no-steroid group developed significantly more endothelial rejection than did the steroid group. A second study elucidated the effectiveness and safety of systemic cyclosporine in high-risk corneal transplantation. The patients were assigned to a systemic cyclosporine or control group. At a mean follow-up of 42.7 months, no difference was observed in the endothelial rejection rates and graft clarity loss between the 2 groups. A third study elucidated the effectiveness and the safety of systemic tacrolimus in high-risk corneal transplantation. Of 11 consecutive eyes decompensated despite systemic cyclosporine treatment, there was no irreversible rejection in eyes treated with tacrolimus, which was significantly better than in previous penetrating keratoplasty with systemic cyclosporine treatment. Prognosis after keratoplasty in patients with keratoconus is relatively good, but special attention is required for patients with atopic dermatitis. Postkeratoplasty atopic sclerokeratitis (PKAS) is a severe form of sclerokeratitis after keratoplasty in atopic patients. Our retrospective study showed that 35 eyes of 29 patients from a total of 247 keratoconus eyes undergoing keratoplasty were associated with atopic dermatitis, of which 6 eyes of 5 patients developed PKAS. Eyes with PKAS had a significantly higher incidence of atopic blepharitis

  3. A comparative, retrospective, observational study of the clinical and microbiological profiles of post-penetrating keratoplasty keratitis

    PubMed Central

    Lin, I-Huang; Chang, Yi-Sheng; Tseng, Sung-Huei; Huang, Yi-Hsun

    2016-01-01

    Infectious keratitis after penetrating keratoplasty (PK) is a devastating condition that may result in graft failure and poor visual outcome. In this study, we retrospectively reviewed the medical records of patients who underwent PK between 2009 and 2014, and recorded those who developed infectious keratitis. We compared the predisposing factors and organisms isolated to those identified in our previous study, conducted between 1989 and 1994. The incidence of post-PK infectious keratitis decreased from 11.6% (41 out of 354 cases, 1989–1994) to 6.5% (9 out of 138 cases, 2009–2014). Graft epithelial defect and suture-related problems remained the leading two risk factors of infectious keratitis after PK. Gram-positive and Gram-negative bacterial infection decreased from 58.5% and 46.3% to 11.1% and 22.2%, respectively (P = 0.023 and P = 0.271). In contrast, fungus infection increased from 9.8% to 66.7% (P = 0.001); fungi have become the major pathogen for post-PK infectious keratitis. In conclusion, while the incidence of post-PK infectious keratitis has decreased over time, the number and frequency of fungal infections have significantly increased in the recent study period. Clinicians should be aware of the shifting trend in pathogens involved in post-PK infectious keratitis. PMID:27587283

  4. Systemic Immunosuppression in High-Risk Penetrating Keratoplasty: A Systematic Review.

    PubMed

    Bali, Shveta; Filek, Richard; Si, Francie; Hodge, William

    2016-04-01

    Cornea transplantation has a high success rate and typically only requires topical immunomodulation. However, in high-risk cases, systemic immunosuppression can be used. We conducted a systematic review on the efficacy and side effects of systemic immunosuppression for high-risk cornea transplantation. The study population was 18 years old or older with a high-risk transplant (two or more clock hours of cornea vascularization or a previous failed graft or a graft needed because of herpes simplex keratitis). A comprehensive search strategy was performed with the help of an information specialist and content experts from ophthalmology. All study designs were accepted for assessment. Level 1 and level 2 screening was performed by two reviewers followed by data abstraction. Forest plots were created whenever possible to synthesize treatment effects. Quality assessment was done with a Downs and Blacks score. From 1,150 articles, 29 were ultimately used for data abstraction. The odds ratios (ORs) for clear graft survival in cyclosporine and controls were 2.43 (95% CI: 1.00 - 5.88) and 3.64 (95% CI: 1.48 - 8.91) for rejection free episodes. Mycophenolate mofetil (MMF) significantly improved the rejection free graft survival rates at 1 year (OR: 4.05, 95% CI: 1.83 - 8.96). The overall results suggested that both systemic cyclosporine and MMF improved 1-year rejection free graft survival in high-risk keratoplasty. Cyclosporine also significantly improved clear graft survival rates at 1 year; however, there were insufficient data to analyze the same in the MMF group. Higher quality studies are needed to understand this issue better. PMID:26985246

  5. Systemic Immunosuppression in High-Risk Penetrating Keratoplasty: A Systematic Review

    PubMed Central

    Bali, Shveta; Filek, Richard; Si, Francie; Hodge, William

    2016-01-01

    Cornea transplantation has a high success rate and typically only requires topical immunomodulation. However, in high-risk cases, systemic immunosuppression can be used. We conducted a systematic review on the efficacy and side effects of systemic immunosuppression for high-risk cornea transplantation. The study population was 18 years old or older with a high-risk transplant (two or more clock hours of cornea vascularization or a previous failed graft or a graft needed because of herpes simplex keratitis). A comprehensive search strategy was performed with the help of an information specialist and content experts from ophthalmology. All study designs were accepted for assessment. Level 1 and level 2 screening was performed by two reviewers followed by data abstraction. Forest plots were created whenever possible to synthesize treatment effects. Quality assessment was done with a Downs and Blacks score. From 1,150 articles, 29 were ultimately used for data abstraction. The odds ratios (ORs) for clear graft survival in cyclosporine and controls were 2.43 (95% CI: 1.00 - 5.88) and 3.64 (95% CI: 1.48 - 8.91) for rejection free episodes. Mycophenolate mofetil (MMF) significantly improved the rejection free graft survival rates at 1 year (OR: 4.05, 95% CI: 1.83 - 8.96). The overall results suggested that both systemic cyclosporine and MMF improved 1-year rejection free graft survival in high-risk keratoplasty. Cyclosporine also significantly improved clear graft survival rates at 1 year; however, there were insufficient data to analyze the same in the MMF group. Higher quality studies are needed to understand this issue better. PMID:26985246

  6. Femtosecond laser enabled keratoplasty for advanced keratoconus

    PubMed Central

    Shivanna, Yathish; Nagaraja, Harsha; Kugar, Thungappa; Shetty, Rohit

    2013-01-01

    Purpose: To assess the efficacy and advantages of femtosecond laser enabled keratoplasty (FLEK) over conventional penetrating keratoplasty (PKP) in advanced keratoconus. Materials and Methods: Detailed review of literature of published randomized controlled trials of operative techniques in PKP and FLEK. Results: Fifteen studies were identified, analyzed, and compared with our outcome. FLEK was found to have better outcome in view of better and earlier stabilization uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and better refractive outcomes with low astigmatism as compared with conventional PKP. Wound healing also was noticed to be earlier, enabling early suture removal in FLEK. Conclusions: Studies relating to FLEK have shown better results than conventional PKP, however further studies are needed to assess the safety and intraoperative complications of the procedure. PMID:23925340

  7. Do topical ophthalmic corticosteroids suppress the hypothalmic-pituitary-adrenal axis in post-penetrating keratoplasty patients?

    PubMed Central

    Sandhu, S S; Smith, J M; Doherty, M; James, A; Figueiredo, F C

    2012-01-01

    Purpose To establish whether hypothalmic-pituitary-adrenal axis suppression is possible secondary to long-term topical ophthalmic corticosteroid use in patients who have undergone penetrating keratoplasty (PKP). Methods Patients who had undergone a PKP and had been using corticosteroid-based eye drops continuously for more than 6 months, with no history of concomitant steroid (oral, inhaled, or cutaneous) use, were included within the study. A low-dose short Synacthen (LDSST) test was performed in each patient followed later by a short Synacthen test (SST). The mean SST and LDSST after 30 min were calculated along with their corresponding 95% confidence intervals (CIs). Correlation between both baseline SST and baseline LDSST with duration of treatment was determined using Spearman's correlation. Results In all, 20 patients were included within the study. The mean duration treatment was 28.2 months (range 11–96 months). All patients had normal baseline cortisol levels in both SST and LDSST tests. The mean 30 min SST was 753.8 nmol/l (95%CI: 696.6 nmol/l, 811.0 nmol/l) and no patients displayed inadequate adrenal response. The mean 30 min LDSST was 709.8 nmol/l (95%CI: 665.1 nmol/l, 754.5 nmol/l) and only one patient had an inadequate adrenal response. There was no correlation between baseline SST or LDSST and duration of treatment. Conclusions This study found no evidence that patients using continuous long-term corticosteroid eye drops after PKP experienced inadequate adrenal response. We did not find any evidence of a negative correlation between length of treatment and SST or LDSST measurements at baseline. PMID:22344184

  8. Evolution of endothelial keratoplasty.

    PubMed

    Price, Francis W; Price, Marianne O

    2013-11-01

    Endothelial keratoplasty has evolved into a popular alternative to penetrating keratoplasty (PK) for the treatment of endothelial dysfunction. Although the earliest iterations were challenging and were not widely adopted, the iteration known as Descemet stripping endothelial keratoplasty (DSEK) has gained widespread acceptance. DSEK combines a simplified technique for stripping dysfunctional endothelium from the host cornea and microkeratome dissection of the donor tissue, a step now commonly completed in advance by eye bank technicians. Studies show that a newer endothelial keratoplasty iteration, known as Descemet membrane endothelial keratoplasty (DMEK), provides an even faster and better visual recovery than DSEK does. In addition, DMEK significantly reduces the risk of immunologic graft rejection episodes compared with that in DSEK or in PK. Although the DMEK donor tissue, consisting of the bare endothelium and Descemet membrane without any stroma, is more challenging to prepare and position in the recipient eye, recent improvements in instrumentation and surgical techniques are increasing the ease and the reliability of the procedure. DSEK successfully mitigates 2 of the main liabilities of PK: ocular surface complications and structural problems (including induced astigmatism and perpetually weak wounds), whereas DMEK further mitigates the 2 principal remaining liabilities of PK: immunologic graft reactions and secondary glaucoma from prolonged topical corticosteroid use. PMID:24104929

  9. Deep Anterior Lamellar Keratoplasty: Indications, Surgical Techniques and Complications

    PubMed Central

    Karimian, Farid; Feizi, Sepehr

    2010-01-01

    The concept of lamellar keratoplasty (LK) is not new. However, it had been abandoned and largely replaced by the time-honored technique of penetrating keratoplasty (PK) because LK is technically demanding, time consuming and gives suboptimal visual outcomes due to interface irregularity arising from manual lamellar dissection. Recent improvements in surgical instruments and introduction of new techniques of maximum depth of corneal dissection as well as inherent advantages such as preservation of globe integrity and elimination of endothelial graft rejection have resulted in a re-introduction of LK as an acceptable alternative to conventional PK. This review article describes the indications, different techniques, clinical outcomes and complications of deep anterior LK. PMID:20543934

  10. Long-Term Safety and Visual Outcomes of Transscleral Sutured Posterior Chamber IOLs and Penetrating Keratoplasty Combined with Transscleral Sutured Posterior Chamber IOLs

    PubMed Central

    Nottage, Jennifer Marie; Bhasin, Vikram; Nirankari, Verinder S.

    2009-01-01

    Purpose: To evaluate the outcomes of consecutive patients who underwent transscleral sutured posterior chamber intraocular lens (TS PCIOL) implantation as well as patients who had combined penetrating keratoplasty (PK) and TS PCIOL. Methods: Data from all patients who had sutured PCIOL insertion performed by the same surgeon (V.S.N.) between January 2003 and June 2007 were compiled and analyzed. Results: Group 1 consisted of 69 eyes of 67 patients who had TS PCIOL only. Mean age was 65.1 years, and mean follow-up was 14.25 months. Mean best spectacle-corrected visual acuity (BSCVA) was 20/80 preoperatively and 20/40 postoperatively. Group 2 consisted of 38 eyes of 37 patients who had combined PK and TS PCIOL. Mean age was 70.21 years, and mean follow-up was 14.29 months. Mean BSCVA was <20/250 preoperatively and between 20/70 and 20/80 postoperatively. In both groups, there were no reported cases of choroidal hemorrhage or hyphema. There was one case (0.9%) of suture erosion (group 1). There were no redislocations, lens tilting, suture breakage, or graft rejections. Postoperative complications included uveitis in 1 eye (0.9%), glaucoma in 5 (4.7%), cystoid macular edema in 6 (5.6%), and retinal detachment in 2 (1.9%). Conclusions: The TS PCIOL procedure, as done by the ab externo method, is safe and effective. It has few intraoperative or postoperative complications, and it improves visual acuity in patients requiring either TS PCIOL alone or combined PK and TS PCIOL. Ultimately, in considering TS PCIOL, patient selection, surgical method, and the surgeon’s comfort with the technique must be weighed. PMID:20126501

  11. Effects of Cataract Surgery on Endothelium in Transplanted Corneal Grafts: Comparison of Extracapsular Cataract Extraction and Phacoemulsification for Complicated Cataract after Penetrating Keratoplasty

    PubMed Central

    Zhou, Hong-Wei; Xie, Li-Xin

    2016-01-01

    Background: The endothelium should be carefully evaluated when choosing a surgical technique for cataract removal. Therefore, we aimed to study the effects of different cataract surgery techniques on endothelial cell loss in transplanted corneal grafts. Methods: A total of 54 patients who received complicated cataract surgery in post-penetrating keratoplasty (PKP) eyes at the Shandong Eye Institute between February 2001 and June 2014 were included, and clinical records were reviewed. Baseline demographic details, clinical characteristics, endothelial cell density (ECD), and best-corrected visual acuity (BCVA) were recorded. Wilcoxon rank-sum test and Wilcoxon signed-rank test were used to test the equality of medians. A regression model was constructed to compare the reduced rate of ECD. Results: Of the 54 eyes included in this study, extracapsular cataract extraction (ECCE) was performed in 34 eyes of 33 patients (ECCE group) whereas phacoemulsification was performed in 20 eyes of 20 patients (phacoemulsification group). There was no significant difference in the median age (P = 0.081) or preoperative ECD (P = 0.585) between the two groups. At 6 months after cataract surgery, ECD in ECCE group was significantly higher than that in phacoemulsification group (P = 0.043). In addition, the endothelial cell loss rate in ECCE group was significantly lower than that in phacoemulsification group at 2 months (P = 0.018), 4 months (P < 0.001), and 6 months (P < 0.001) after cataract surgery. Endothelial cell loss rate after cataract surgery increased over the 6-month study duration in both ECCE group (P < 0.001) and phacoemulsification group (P < 0.001), but phacoemulsification resulted in a greater reduction in ECD than that of ECCE in transplanted corneal grafts (P < 0.001). There was no significant difference in postoperative BCVA between the two groups (P = 0.065). Conclusion: ECCE is more suitable than phacoemulsification in cataract surgery in complicated cataract

  12. [Keratoplasty combined with cataract surgery].

    PubMed

    Muraine, M; Gueudry, J; Retout, A; Genevois, O

    2012-09-01

    Corneal pathologies leading to keratoplasty are often associated with cataract and combined surgery is therefore mandatory. Triple procedure with penetrating keratoplasty and concurrent cataract extraction followed by intra ocular lens (IOL) implantation is usually the preferential choice because visual rehabilitation is theoretically more rapid. Surgeons have to be aware of surgical conditions during open-sky surgery because vitreous pressure is not counterbalanced by anterior chamber pressure. Today, many surgeons prefer non-simultaneous procedures with cataract surgery performed months after grafting because of the improvement in spherical refractive error. More recently, new triple procedures, Descemet's stripping automated keratoplasty and concurrent cataract surgery have gained popularity, especially in patients with Fuchs dystrophy associated with cataract. Surgery starts with phacoemulsification, followed by endothelium exchange through a 3 to 5 mm incision. Advantages against classic triple procedure are quick visual rehabilitation, fewer induced refractive errors, minimal postoperative discomfort and corneal integrity. Surgeons have to consider an eventual postoperative hyperopic shift secondary to corneal lenticule shape when choosing adequate intraocular lens. PMID:22921023

  13. Indications for and techniques of keratoplasty at Vietnam National Institute of Ophthalmology

    PubMed Central

    Dong, Pham Ngoc; Han, Truong Nhu; Aldave, Anthony J.; Chau, Hoang Thi Minh

    2016-01-01

    AIM To report the indications for and techniques of corneal transplantation at Vietnam National Institute of Ophthalmology (VNIO) over a period of 12y (2002-2013). METHODS Records of patients who had undergone corneal transplantation at VNIO from January 1, 2002 to January 1, 2014 were reviewed to determine the indication for and type of corneal transplant performed. Patient age, gender, indication for corneal transplantation and surgical technique were recorded and analyzed. RESULTS Corneal transplantation were underwent in 1390 eyes of 1278 patients with a mean age of 44.9±18.1y during the period under review. The most common indication was infectious corneal ulcer (n=670; 48.2%), followed by corneal scar (n=333, 24.0%), corneal dystrophy (n=138, 9.9%) and failed graft (n=112, 8.1%). Nearly all procedures performed were penetrating keratoplasty (n=1300, 93.5%), with a few lamellar keratoplasty procedures performed: lamellar keratoplasty (n=52, 3.7%), Descemet's stripping automated endothelial keratoplasty (n=27, 1.9%) and deep anterior lamellar keratoplasty (n=11, 0.8%). CONCLUSION While the most common indication for keratoplasty was infectious keratitis, nearly all indications for corneal transplantation were managed with penetrating keratoplasty. However, lamellar keratoplasty techniques, including deep anterior lamellar keratoplasty and Descemet's stripping automated endothelial keratoplasty, are being performed with increasing frequency for isolated stromal and endothelial disorders, respectively. PMID:27158606

  14. Measuring skin penetration by confocal Raman microscopy (CRM): correlation to results from conventional experiments

    NASA Astrophysics Data System (ADS)

    Lunter, Dominique; Daniels, Rolf

    2016-03-01

    Confocal Raman microscopy has become an advancing technique in the characterization of drug transport into the skin. In this study the skin penetration of a local anesthetic from a semisolid preparation was investigated. Furthermore, the effect of the chemical enhancers propylene glycol and POE-23-lauryl ether on its penetration was investigated. The results show that confocal Raman microscopy may provide detailed information on the penetration of APIs into the skin and may elucidate their distribution within the skin with high resolution. The results of the CRM analysis are fully in line with those of conventional permeation and penetration experiments.

  15. Canopy penetration and deposition of barrier sprays from electrostatic and conventional sprayers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experimental study was conducted to investigate the effectiveness of barrier sprays from electrostatic and conventional sprayers through measurement of penetration into and deposition on to natural vegetation. Two conventional and three electrostatic sprayers were used in the study. One sprayer...

  16. Current techniques of lamellar keratoplasty for keratoconus

    PubMed Central

    Spadea, Leopoldo; Rosa, Victoria De

    2016-01-01

    In recent years, there has been a considerable interest regarding the concept of lamellar keratoplasty (LK), which contributed in spreading the use of this procedure in the treatment of keratoconus. This is a new frontier in corneal surgery that minimizes trauma on the recipient patient since it works on a “closed bulb”. The LK surgery, in fact, aims to selectively replace diseased corneal stroma, leaving the healthy endothelium. The main advantage of LK is to avoid major causes of failure of penetrating keratoplasty as immunological rejection, and the late mismatch in the transplanted cornea, thus increasing the life of transplantation. In the last decade, several techniques of LK have been proposed, depending on how the anterior portion of the recipient cornea is removed. This article, through a literary research reviews the various emerging techniques of anterior lamellar surgery for the management of keratoconus, analyzing their indications, visual outcomes, and rate of complications. PMID:26837393

  17. [Refractive changes after Descemet membrane endothelial keratoplasty].

    PubMed

    Röck, T; Bartz-Schmidt, K U; Röck, D; Yoeruek, E

    2014-01-01

    Penetrating keratoplasty has different refractive disadvantages in contrast to posterior lamellar keratoplasty. For example, a decentered corneal trephination and a tilted trephination or unevenly tightened corneal sutures can cause an uncontrolled high astigmatism as well as a refractive change. Also the postoperative refraction may change over time as a result of wound healing, suture loosening or suture removal. The aim of this retrospective study was to investigate a possible refractive change after Descemet membrane endothelial keratoplasty (DMEK). A total of 139 pseudophakic eyes from 125 patients with endothelial decompensation had undergone DMEK surgery at the Tübingen Eye Clinic. After a mean postoperative time of 13.15 ± 2.98 months after DMEK discreet mean changes in the spherical equivalent of + 0.37 ± 0.87 diopters and the cylinder to - 0.45 ± 0.57 diopters were observed. The mean central corneal thickness decreased from 670 ± 70 µm to 544 ± 55 µm. In conclusion after DMEK a discreet induced hyperopic refractive shift due to the reversal of stromal swelling was observed. PMID:23989219

  18. Lamellar keratoplasty in keratoconus.

    PubMed

    Vancea, P P; Schwartzenberg, T

    1979-11-01

    The authors present the results of 11 keratoplasties in cases of keratoconus, comparing the visual acuity and the ocular refraction before and after the operation (ophtalmometry, objective and subjective refractometry). The statistical data indicate a meaningful flattening of the corneal curvature (12.84 dpt average) and a mean reduction of the myopia for 8.227 dpt. In fact, the basic regular astigmatism of the cornea had not been altered. The mean visual acuity was 0.68 (with an improvement of 0.495). No further damage of acuity had been observed. After 10 to 69 months a medical checkup revealed transparent grafts in five cases; four presented small maculae; one, thin folds of Descemet's membrane. Based on the authors' experience and on the literature, the paper recommends lamellar keratoplasty in cases of keratoconus, the surgeon must choose the appropriate moment in the course of the development of this disease. PMID:395850

  19. Canopy penetration and deposition of barrier sprays from electrostatic and conventional sprayers.

    PubMed

    Hoffmann, W C; Farooq, M; Walker, T W; Fritz, B; Szumlas, D; Quinn, B; Bernier, U; Hogsette, J; Lan, Y; Huang, Y; Smith, V L; Robinson, C A

    2009-09-01

    An experimental study was conducted to investigate the usefulness of electrostatic and conventional sprayers for barrier applications. Two conventional and three electrostatic sprayers were used in the study. Usefulness of the sprayers was rated based on penetration of spray into and deposition onto 2 sides of leaves on natural vegetation. Bifenthrin (Talstar adulticide) was applied at labeled rate, fluorescent dye was added to the tank mix as tracer, and all sprayers applied the dye and insecticide at the same rate. The results indicated that sprayers producing larger droplets produced significantly higher deposition on vegetation in barrier applications than the sprayers producing smaller droplets. Sprayers with higher air velocity at the nozzle discharge proved significantly better for barrier sprays than the sprayers with lower air velocity. Electrostatic sprayers did not show any improvement in deposition on vegetation or in penetration into vegetation over the conventional sprayers. There was no difference in deposition between truck-mounted and backpack sprayers. PMID:19852223

  20. On Evaluating Cycling and Movement of Conventional Generators for Balancing Services with Large Solar Penetration

    SciTech Connect

    Diao, Ruisheng; Lu, Shuai; Ma, Jian

    2012-05-07

    Abstract— The increasing uncertainty caused by a higher penetration level of renewable energy points to the need for sufficient balancing services to ensure secure operation. It is thus of necessity to accurately quantify these services and evaluate the cycling and movement of conventional generators providing load following and regulation services for optimally planning and scheduling multiple resources. This paper first introduces a systematic approach to calculating load following and regulation requirements with a large amount of solar integration. Then, two methods to quantitatively determine the cycling of conventional generators are proposed, including (1) mileage and number of direction changes in balancing service and (2) ramp statistics (or half-cycle) analysis. The proposed methods are tested on the NV Energy power system model. Simulation results demonstrate a significant impact of increased solar capacity on balancing service and cycling of conventional generators. Busy hours are identified for different study scenarios with various solar penetration levels. This study provides a basis for evaluating the wear and tear of the conventional generators in the solar integration process in the Nevada power system. Index Terms—balancing requirement, conventional generator, cycling and movement, load following, regulation, renewable energy, solar integration

  1. A case of acute postoperative keratitis after deep anterior lamellar keratoplasty by multidrug resistant Klebsiella

    PubMed Central

    Bajracharya, Leena; Sharma, Binita; Gurung, Reeta

    2015-01-01

    A healthy lady of 42 years underwent deep anterior lamellar keratoplasty for granular dystrophy. The very next day, it was complicated by development of infectious keratitis. The organism was identified as multidrug resistant Klebsiella pneumoniae. Donor corneal button may be implicated in the transmission of infection in an otherwise uneventful surgery and follow-up. Nosocomial infections are usually severe, rapidly progressive and difficult to treat. Finally, the lady had to undergo therapeutic penetrating keratoplasty for complete resolution of infection. PMID:26044477

  2. Keratoplasty for keratomalacia in preschool children

    PubMed Central

    Vajpayee, R B; Vanathi, M; Tandon, R; Sharma, N; Titiyal, J S

    2003-01-01

    Aim: To study the results of surgical management of keratomalacia in children. Methods: A clinical case series of all children with keratomalacia, admitted to an Indian centre during the period from June 2000 to June 2001 is presented. The parameters evaluated were demographic data, systemic associations, and results of medical and surgical intervention. Results: 29 children with keratomalacia ranging from 2 months to 5 years of age (mean 1.8 (SD 1.4) years) were included in the study. All children belonged to families of lower socioeconomic status. 27 patients (93.1%) had not been immunised at all. The systemic diseases precipitating the onset of keratomalacia included measles (41.37%), pneumonia (31.03%), and acute diarrhoea (37.93%). 36 eyes (66.7%) had total corneal melting and 11 (20.3%) eyes had paracentral corneal melting. In 15 eyes (27.8%) an emergency tectonic penetrating keratoplasty was performed of which only five grafts (33.3%) remained clear at a mean follow up of 7.3 (6.8) months (range 3–24 months). Seven eyes underwent optical penetrating keratoplasty, of which four grafts (57.14%) remained clear at a mean follow up of 6.4 (3.6) months (range 3–12 months). None of these could achieve a visual acuity better than 6/60. Conclusions: Corneal grafting surgery in keratomalacia is associated with poor visual outcome. PMID:12714386

  3. Blowout Fracture after Descemet's Stripping Automated Endothelial Keratoplasty

    PubMed Central

    Tachibana, Eri; Koh, Shizuka; Maeda, Naoyuki; Nishida, Kohji

    2014-01-01

    We present the case of an 86-year-old woman who developed a blowout fracture after Descemet's stripping automated endothelial keratoplasty (DSAEK). Sixteen months after DSAEK, she suffered a blow to her left eye caused by a fall. Computed tomography confirmed the presence of a blowout fracture of the inferior wall of the left orbit with soft tissue prolapsing into the orbit. The patient complained of no abnormal symptoms, and her operated cornea was intact and clear. There was no abnormal finding in both the anterior and posterior segments. This case highlights that the DSAEK technique provides adequate tectonic stability of the globe throughout the traumatic event in contrast to penetrating keratoplasty, which can lead to devastating vision damage after trauma. PMID:25759661

  4. Blowout Fracture after Descemet's Stripping Automated Endothelial Keratoplasty.

    PubMed

    Tachibana, Eri; Koh, Shizuka; Maeda, Naoyuki; Nishida, Kohji

    2014-01-01

    We present the case of an 86-year-old woman who developed a blowout fracture after Descemet's stripping automated endothelial keratoplasty (DSAEK). Sixteen months after DSAEK, she suffered a blow to her left eye caused by a fall. Computed tomography confirmed the presence of a blowout fracture of the inferior wall of the left orbit with soft tissue prolapsing into the orbit. The patient complained of no abnormal symptoms, and her operated cornea was intact and clear. There was no abnormal finding in both the anterior and posterior segments. This case highlights that the DSAEK technique provides adequate tectonic stability of the globe throughout the traumatic event in contrast to penetrating keratoplasty, which can lead to devastating vision damage after trauma. PMID:25759661

  5. Fungal interface keratitis by Candida orthopsilosis following deep anterior lamellar keratoplasty

    PubMed Central

    Wessel, Julia M; Bachmann, Björn O; Meiller, Ralph; Kruse, Friedrich E

    2013-01-01

    A 39-year-old male patient underwent uncomplicated deep anterior lamellar keratoplasty due to keratoconus. On day 5 after surgery, small whitish infiltrates developed in the corneal interface. The diagnosis of fungal keratitis was made when the culture medium of the graft grew Candida after the surgical intervention. Despite intensive antimycotic treatment and irrigation of the interface, the infiltrates persisted and eventually enlarged. Therefore, revision surgery with penetrating keratoplasty was performed. Microbiological analysis showed Candida orthopsilosis in the culture of the excised graft button. Histopathological staining of the excised graft showed periodic acid–Schiff-positive and Grocott methenamine silver-positive clusters of yeast between Descemet's membrane and the deep corneal stroma with focal perforations through Descemet's membrane. The treatment of mycotic keratitis caused by C orthopsilosis is challenging. Antimycotic treatment was unsuccessful in this case. Progression of the keratitis and perforation of Descemet's membrane suggest that early surgical intervention by penetrating keratoplasty is required. PMID:23349184

  6. Ocular biomechanical measurements on post-keratoplasty corneas using a Scheimpflug-based noncontact device

    PubMed Central

    Modis, Laszlo; Hassan, Ziad; Szalai, Eszter; Flaskó, Zsuzsanna; Berta, Andras; Nemeth, Gabor

    2016-01-01

    AIM To analyse ocular biomechanical properties, central corneal thickness (CCT) and intraocular pressure (IOP) in post-keratoplasty eyes, as compared to normal subjects, with a new Scheimpflug-based technology. Moreover, biomechanical data were correlated with the size and age of the donor and recipient corneas. METHODS Measurements were conducted on 46 eyes of 46 healthy patients without any corneal pathology (age: 53.83±20.8y) and 30 eyes of 28 patients after penetrating keratoplasty (age: 49.43±21.34y). Ten biomechanical parameters, the CCT and IOP were recorded by corneal visualization scheimpflug technology (CorVis ST) using high-speed Scheimpflug imaging. Keratometry values were also recorded using Pentacam HR system. Scheimpflug measurements were performed after 43.41±40.17mo (range: 11-128mo) after the keratoplasty and after 7.64±2.34mo (range: 5-14mo) of suture removal. RESULTS Regarding the device-specific biomechanical parameters, the highest concavity time and radius values showed a significant decrease between these two groups (P=0.01 and P<0.001). None of other biomechanical parameters disclosed a significant difference. The CCT showed a significant difference between post-keratoplasty eyes as compared to normal subjects (P=0.003) using the CorVis ST device. The IOP was within the normal range in both groups (P=0.84). There were no significant relationships between the keratometric data, the size of the donor and recipient, age of the donor and recipient and biomechanical properties obtained by CorVis ST. CONCLUSION The ocular biomechanics remain stable after penetrating keratoplasty according to the CorVis ST measurements. Only two from the ten device-specific parameters have importance in the follow-up period after penetrating keratoplasty. PMID:26949641

  7. Descemet stripping automated endothelial keratoplasty in pediatric age group☆

    PubMed Central

    Madi, Silvana; Santorum, Paolo; Busin, Massimo

    2012-01-01

    Purpose To report the outcomes of DSAEK surgery performed in pediatric patients. Design Noncomparative interventional case series. Subjects and methods All pediatric patients (age up to 16 years) undergoing Descemet automated stripping endothelial keratoplasty (DSAEK) at our Institution since January 2008 have been enrolled in a prospective study. A standard DSAEK, involving delivery of an 8.5–9.5 mm graft by Busin glide, was performed under general anesthesia in 19 eyes of 11 pediatric patients (congenital hereditary endothelial dystrophy n = 13; congenital glaucoma n = 2; posterior polymorphous dystrophy n = 2, and failed penetrating keratoplasty n = 2). Slit-lamp examination, refraction and visual acuity as well as endothelial cell density were evaluated preoperatively as well as 1, 3, 6, 12, and 18 months postoperatively. Results All surgical procedures were uneventful. Graft detachment occurred in 4 cases and was managed successfully with repeat air injection. All corneas cleared within a week from surgery. Follow-up was 3–18 months. At last follow-up examination, best-corrected visual acuity (BCVA) was better than 20/40 in 8 of the 13 cases of patients old enough to assess vision. A graft rejection episode was seen in 1 case within 3 months from surgery but was reverted with steroidal treatment. No graft failures were observed. Conclusions DSAEK is an appropriate surgical intervention for children with corneal endothelial failure. In contrast to penetrating keratoplasty (PK), DSAEK is performed under “closed system” conditions, thus minimizing intraoperative risks. Finally, healing is much faster than with PK and all sutures can be removed within 2–4 weeks from surgery, thus allowing fast visual recovery and prompt starting of amblyopia treatment. PMID:23961011

  8. Penetrator reliability investigation and design exploration : from conventional design processes to innovative uncertainty-capturing algorithms.

    SciTech Connect

    Martinez-Canales, Monica L.; Heaphy, Robert; Gramacy, Robert B.; Taddy, Matt; Chiesa, Michael L.; Thomas, Stephen W.; Swiler, Laura Painton; Hough, Patricia Diane; Lee, Herbert K. H.; Trucano, Timothy Guy; Gray, Genetha Anne

    2006-11-01

    This project focused on research and algorithmic development in optimization under uncertainty (OUU) problems driven by earth penetrator (EP) designs. While taking into account uncertainty, we addressed three challenges in current simulation-based engineering design and analysis processes. The first challenge required leveraging small local samples, already constructed by optimization algorithms, to build effective surrogate models. We used Gaussian Process (GP) models to construct these surrogates. We developed two OUU algorithms using 'local' GPs (OUU-LGP) and one OUU algorithm using 'global' GPs (OUU-GGP) that appear competitive or better than current methods. The second challenge was to develop a methodical design process based on multi-resolution, multi-fidelity models. We developed a Multi-Fidelity Bayesian Auto-regressive process (MF-BAP). The third challenge involved the development of tools that are computational feasible and accessible. We created MATLAB{reg_sign} and initial DAKOTA implementations of our algorithms.

  9. Adult keratoplasty: has the prognosis improved in the last 25 years?

    PubMed

    Price, Francis W; Price, Marianne O

    2008-06-01

    Adult keratoplasty outcomes have significantly improved in the past quarter century as a result of new pharmaceuticals, advanced surgical devices, better understanding of what causes graft failure, and targeted techniques for selective replacement of only diseased corneal layers. Prevention and treatment of graft rejection, which has long been a leading cause of graft failure, has improved with the development of innovative topical and systemic immuno-suppressants. New methods for preventing and treating ocular surface complications have been devised, and limbal stem cell grafts have significantly improved management of severe ocular surface disease. Improved intraocular lens designs cause less corneal damage and have increased corneal graft survival. Non-steroidal anti-inflammatory (NSAID) eyedrops and more complete vitrectomies have reduced the incidence of chronic cystoid macular edema, which could prevent eyes with clear grafts from regaining useful vision. Patients with keratoconus or corneal scars can now benefit from advanced anterior lamellar keratoplasty techniques, which reduce the risk of immunologic rejection and endothelial failure, while matching the visual outcomes achieved with penetrating keratoplasty. Patients with endothelial dysfunction can now benefit from advanced endothelial keratoplasty techniques, which provide more rapid visual recovery, minimize induced astigmatism and ocular surface problems, and virtually eliminate the risk of wound rupture from minor trauma. Finally, femtosecond lasers now provide transplant surgeons with a precise tool for creating complex, interlocking corneal incisions that may facilitate wound healing. PMID:18196207

  10. Tono-Pen tonometry in normal and in post-keratoplasty eyes.

    PubMed Central

    Geyer, O; Mayron, Y; Loewenstein, A; Neudorfer, M; Rothkoff, L; Lazar, M

    1992-01-01

    Oculab Tono-Pen tonometry was compared with Goldmann applanation tonometry in 82 eyes of 82 patients with normal corneas and in 54 eyes of 54 patients who had undergone penetrating keratoplasty and whose corneas did not preclude the use of Goldmann tonometer. We found that the intraocular pressure (IOP) in 48% of the eyes with normal corneas and in 57% after keratoplasty has different measurements with Goldmann and Tono-Pen pressures of 3 mm Hg or more. Despite the correlation between the Goldmann tonometer and the Tono-Pen in the group of eyes with normal corneas (r = 0.83) as well as in the group of eyes after keratoplasty (r = 0.79) the Tono-Pen tended to significantly overestimate the Goldmann tonometer reading (p < 0.0001). The mean difference between the two instruments was highest across the lower IOP range (< 9 mm Hg) in the group of eyes after keratoplasty. Because the mean absolute values of the paired differences between Goldmann and Tono-Pen measurements varied significantly across all IOP intervals it was not possible to establish a correction factor which could be used when comparing the two measurements. Based on this study the Tono-Pen consistently overestimated the actual IOP in an unpredictable manner. Where possible Goldmann measurements of the IOP are still to be preferred. PMID:1420058

  11. Current Approaches for Management of Postpenetrating Keratoplasty Astigmatism

    PubMed Central

    Feizi, Sepehr; Zare, Mohammad

    2011-01-01

    A successful corneal graft requires both clarity and an acceptable refraction. A clear corneal graft may be an optical failure if high astigmatism limits visual acuity. Intraoperative measures to reduce postkeratoplasty astigmatism include round and central trephination of cornea with an adequate size, appropriate sutures with evenly distributed tension, and perfect graft-host apposition. Suture manipulation has been described for minimising early postoperative astigmatism. If significant astigmatism remains after suture removal, which cannot be corrected by optical means, then further surgical procedures containing relaxing incisions, compression sutures, laser refractive surgery, insertion of intrastromal corneal ring segments, wedge resection, and toric intraocular lens implantation can be performed. When astigmatism cannot be reduced using one or more abovementioned approaches, repeat penetrating keratoplasty should inevitably be considered. However, none of these techniques has emerged as an ideal one, and corneal surgeons may require combining two or more approaches to exploit the maximum advantages. PMID:21811668

  12. Deep anterior lamellar keratoplasty in the management of keratoconus.

    PubMed

    Fogla, Rajesh

    2013-08-01

    Advanced cases of keratoconus often require surgical intervention to restore corneal anatomy and improve eyesight. Penetrating keratoplasty (PK) although commonly performed has potential risk of immunological rejection and is now no longer automatically the first choice of surgery. DALK procedures have evolved, which allows surgical replacement of recipient's corneal stroma, leaving behind healthy descemet membrane (DM) and endothelium. This reduces the risk of allograft endothelial rejection and late graft failure. In recent times, DALK techniques have led to significant improvements in visual outcome and current results are comparable to PK. Big bubble technique of DALK has become the most popular among the various surgical techniques described. Manual near DM DALK also gives good outcome although the visual recovery is often delayed. Future integration of femtosecond laser technology along with diagnostic imaging technology is likely to further improve outcomes of DALK in keratoconus. PMID:23925339

  13. Expanding the scope of lamellar keratoplasty.

    PubMed Central

    Rich, L F

    1999-01-01

    PURPOSE: To investigate whether applications of current technology, such as cryolathe and excimer laser, might improve outcomes and increase use of lamellar keratoplasty. METHODS: Six studies were performed, beginning with animals and progressing to human subjects. The first study compared cryolathed with hand-dissected rabbit corneas to ascertain which created a smoother donor interface. The second animal pilot study was done to determine whether thickness of donor cornea resection could be accurately predicted with the cryolathe. A prospective animal trial was then undertaken to compare lamellar keratoplasty outcomes using cryolathed versus hand-dissected tissue. The fourth work extrapolated previous animal findings to lamellar keratoplasty in human disease. Finally, two ongoing studies are described. The first explores the possibility of sutureless lamellar keratoplasty. The second utilizes the excimer laser to dissect the recipient stromal bed. RESULTS: The initial animal pilot study demonstrated a clearer stromal surface in cryolathed versus hand-dissected corneal tissue. The second pilot showed that plano-powered donor tissue could be generated to predetermined thickness. The prospective animal trial revealed that clear grafts of intended thickness could be obtained with cryolathing. Human studies suggested that lamellar keratoplasty using cryolathe-prepared donor tissue may offer superior results to free-hand dissection. Finally, one ongoing study indicates that sutureless lamellar keratoplasty is untenable, and the other shows that clear grafts can be obtained by combining cryolathed donor tissue with recipient photoablation. CONCLUSION: This body of work demonstrates that use of new lamellar keratoplasty technology may offer expanded scope and better outcomes than traditional lamellar keratoplasty techniques. Images FIGURE 1 FIGURE 3 FIGURE 4A FIGURE 4B FIGURE 8A FIGURE 8B FIGURE 9 FIGURE 10 FIGURE 10B FIGURE 11A FIGURE 11B FIGURE 12A FIGURE 12B FIGURE 13

  14. Development of Selective Lamellar Keratoplasty within an Asian Corneal Transplant Program: The Singapore Corneal Transplant Study (An American Ophthalmological Society Thesis)

    PubMed Central

    Tan, Donald; Ang, Marcus; Arundhati, Anshu; Khor, Wei-Boon

    2015-01-01

    Purpose: To evaluate outcomes of anterior lamellar keratoplasty (ALK) and endothelial keratoplasty (EK) within the Singapore Corneal Transplant Study (SCTS), with the hypothesis that both ALK and EK are able to provide equivalent or improved clinical outcomes, compared to penetrating keratoplasty (PK), and to determine changing trends globally with other international databases. Methods: Clinical data on all transplants performed was derived from our SCTS database, a prospective national keratoplasty registry, and clinical outcomes (graft survival, endothelial cell loss, complications, visual acuity) were compared between PK, ALK, and EK. Global trends on indications and forms of keratoplasty performed in 2011/2012 were obtained from national keratoplasty or eye banking registries, corneal/ophthalmological societies, national eye banks, and national ophthalmic institutions. Results: Global rates of EK surgery vary widely, from 52% (Sweden) to 0% (South Africa), with higher adoption by industrialized countries. ALK adoption rates similarly vary from 28.7% (China) to 1.0% (Philippines). SCTS data show high adoption rates in Singapore: EK 44% and ALK 28%. Our surgical modifications to big-bubble deep anterior lamellar keratoplasty (DALK) surgery resulted in visual outcomes matching PK, and a low conversion to PK of 2.1%, whereas our evolving approaches to donor insertion in Descemet’s stripping automated endothelial keratoplasty (DSAEK) show significant reduction in 1-year postoperative endothelial cell loss rates from 60% (folding), to 22% to 30% (Sheets Glide), to 15% (EndoGlide inserter). Conclusion: Improvements in various forms of ALK and EK surgery can lead to better visual outcomes, longer graft survival, and reduced complications, as compared to PK. Global trends suggest adoption of these procedures at different rates. PMID:26755854

  15. Investigation on penetration of three conventional foodstuffs packaging polymers with two different thicknesses by larvae and adults of major species of stored-product pest insects.

    PubMed

    Allahvaisi, Somayeh; Purmirza, Ali Asghar; Safaralizade, Mohamad Hasan

    2009-01-01

    Despite modern methods of packaging, stored agricultural products are still under attack by stored-insect pests. Therefore, determination of the best polymer and appropriate thickness inhibiting the penetration of the insects must be considered. In this study, we investigated the ability of penetration and the rates of contamination by nine important stored product pest insects for three conventional flexible polymers (polyethylene, cellophane and polypropylene) at two thicknesses (16.5 and 29 microm), which are used as pouches for packing of agricultural products. We used adults of T. castaneum (Coleoptera), S. granarius (Coleoptera), R. dominica (Coleoptera), C. maculates (Coleoptera), O. surinamensis (Coleoptera), and larvae of P. interpunctella (Lepidoptera), E. kuehniella (Lepidoptera), S. cerealella (Lepidoptera) and T. granarium (Coleoptera). Results showed that for most of the species penetration occurred between 4 days and 2 weeks, but there were significant differences (p < or = 0.05) in the penetration of three polymers (cellophane, polyethylene and polypropylene) by the insects. Among the polymers, polyethylene with a thickness of 16.5 microm showed the highest degree of penetration and was the most unsuitable polymer for packaging of foodstuffs. Application of this polymer led to a complete infestation of the product and a lot of punctures were created by the insects. In contrast, no penetration was observed in polypropylene polymer with a thickness of 29 microm. Furthermore, adults and larvae of all species showed a much lower penetration when there was no food present in the pouches and this was the case for all polymers tested. PMID:20222605

  16. Differential impact of high and low penetrance TNFRSF1A gene mutations on conventional and regulatory CD4+ T cell functions in TNFR1-associated periodic syndrome.

    PubMed

    Pucino, Valentina; Lucherini, Orso Maria; Perna, Francesco; Obici, Laura; Merlini, Giampaolo; Cattalini, Marco; La Torre, Francesco; Maggio, Maria Cristina; Lepore, Maria Teresa; Magnotti, Flora; Galgani, Mario; Galeazzi, Mauro; Marone, Gianni; De Rosa, Veronica; Talarico, Rosaria; Cantarini, Luca; Matarese, Giuseppe

    2016-05-01

    TNFR-associated periodic syndrome is an autoinflammatory disorder caused by autosomal-dominant mutations in TNFRSF1A, the gene encoding for TNFR superfamily 1A. The lack of knowledge in the field of TNFR-associated periodic syndrome biology is clear, particularly in the context of control of immune self-tolerance. We investigated how TNF-α/TNFR superfamily 1A signaling can affect T cell biology, focusing on conventional CD4(+)CD25(-) and regulatory CD4(+)CD25(+) T cell functions in patients with TNFR-associated periodic syndrome carrying either high or low penetrance TNFRSF1A mutations. Specifically, we observed that in high penetrance TNFR-associated periodic syndrome, at the molecular level, these alterations were secondary to a hyperactivation of the ERK1/2, STAT1/3/5, mammalian target of rapamycin, and NF-κB pathways in conventional T cells. In addition, these patients had a lower frequency of peripheral regulatory T cells, which also displayed a defective suppressive phenotype. These alterations were partially found in low penetrance TNFR-associated periodic syndrome, suggesting a specific link between the penetrance of the TNFRSF1A mutation and the observed T cell phenotype. Taken together, our data envision a novel role for adaptive immunity in the pathogenesis of TNFR-associated periodic syndrome involving both CD4(+) conventional T cells and Tregs, suggesting a novel mechanism of inflammation in the context of autoinflammatory disorders. PMID:26598380

  17. Outcomes of femtosecond laser-assisted mushroom-configuration keratoplasty in advanced keratoconus.

    PubMed

    Fung, S S M; Aiello, F; Maurino, V

    2016-04-01

    PurposeTo evaluate the long-term outcomes after femtosecond laser (FSL)-assisted mushroom-configuration keratoplasty in advanced keratoconus.Patients and methodsThirteen eyes with Amsler-Krumeich stage IV keratoconus underwent FSL-assisted mushroom-configuration penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK) at a tertiary referral centre. Preoperative risk factors included low orneal thickness, high keratometry measurements, previous hydrops, and central stromal scarring. Main outcome measures were visual acuity and refractive outcome.ResultsThe median follow-up was 33 months (range: 4-43). Preoperatively, the mean corrected distance visual acuity (CDVA) was 1.22±0.47 LogMAR (range: 0.5-1.9 LogMAR), mean minimum corneal thickness was 282±100.8 μm (range: 147-478 μm), and mean average keratometric (K) value was 63.4±7.63 dioptre (D; range: 57.0-75.7 D). Four patients underwent PKP and nine underwent DALK (two converted to PKP). Five patients subsequently underwent a modified arcuate mushroom interface dissection (AMID) procedure for astigmatic correction. At the final follow-up, the mean CDVA was 0.05±0.13 LogMAR (range: -0.10 to 0.20 LogMAR), mean spherical equivalent was -3.21±3.21D, mean cylindrical refractive error was 3.23±2.20 D, and mean average K was 43.1±1.53 D. Complications included early graft dehiscence, corneal vascularisation, stromal rejection, and sclerokeratitis. Sutures were completely removed at the mean 18.4 months for PKP and 9.1 months for DALK postoperatively.ConclusionFSL-assisted mushroom-configuration keratoplasty is feasible and safe in patients with stage IV keratoconus. AMID could further enhance the refractive outcome safely. PMID:26795410

  18. [Complications of Descemet's membrane endothelial keratoplasty].

    PubMed

    Spaniol, K; Borrelli, M; Holtmann, C; Schrader, S; Geerling, G

    2015-12-01

    Descemet's membrane endothelial keratoplasty (DMEK) is a relatively new, but now established surgical procedure to cure corneal endothelial disorders. However, there are donor- and recipient-associated sources of potential complications, some of which can be identified and addressed prior to the procedure and others that may lead to intra- or postoperative problems. Preoperatively, risk factors for a limited visual outcome (ocular comorbidities, previous ocular surgery, subepithelial/stromal scars) and the specific indication for DMEK should be discussed with the patient. Intraoperatively, young donor age can be associated with a particularly elastic graft, which may be difficult to unfold. Such transplants are not appropriate for particularly difficult recipient situations (very opaque cornea, history of vitreoretinal surgery). Postoperatively, transplant dehiscence is the most common complication, which in many cases can be managed by reinjection of air (or a 20 % SF6 gas/air mix) into the anterior chamber. An elevation of the intraocular pressure after DMEK is often caused by a reaction to topical steroid therapy. Although immune rejections after DMEK are less likely than after Descemet's stripping automated endothelial keratoplasty (DSAEK) and perforating keratoplasty, adequate treatment with topical steroidal drugs is recommended. These common and several rare complications are discussed in this review. PMID:26597643

  19. Root distribution in a California semi-arid oak savanna ecosystem as determined by conventional sampling and ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Koteen, L. E.; Raz-Yaseef, N.; Baldocchi, D. D.

    2011-12-01

    Koteen, Laura E., Raz-Yaseef, Naama, and Dennis D. Baldocchi University of California, Berkeley California's blue oak, Quercus douglasii, is a unique tree in several ways. Despite the intense heat of California's central valley and Sierra foothills, and absence of precipitation during dry summer months, blue oaks are winter deciduous, and rely on a suite of drought adaptation measures for highly-efficient water use. To date, much more is known about aboveground dynamics in semi-arid oak savanna ecosystems than belowground. Yet, the root system is instrumental in ensuring oak survival and in determining the magnitude and timing of land-atmospheric fluxes via its control of water and nutrient supply to aboveground processes and soil moisture content. Tree root distribution is notoriously heterogeneous. Therefore a comprehensive sampling effort is needed in order to optimally represent it. To further understand the patterns of water use in oak savanna ecosystems in the Sierra foothills of California, we have sought to characterize the root system by depth. To accomplish this goal, we have sampled the root system using conventional sampling methods (i.e. pit and core sampling), in conjunction with ground penetrating radar (GPR). Using both methods together made it possible to compensate for the limitations of each: Fine roots can only be detected by conventional sampling, and involve time intensive work in the lab, limiting sample size. GPR, on the other hand, allows for much greater spatial coverage and therefore more comprehensive characterization of the coarse root component. An extensive field campaign was executed during May 2011. 7 tree areas where chosen, representing the range of tree sizes and composition at the research site: 2 small trees, 2 large trees and 2 tree clusters. One additional very large tree that has undergone extensive additional physiological measurements was also chosen in order to posit and test hypotheses about linkages among root, soil

  20. Boston type 1 keratoprosthesis for failed keratoplasty.

    PubMed

    Hager, Jonathan L; Phillips, David L; Goins, Kenneth M; Kitzmann, Anna S; Greiner, Mark A; Cohen, Alex W; Welder, Jeffrey D; Wagoner, Michael D

    2016-02-01

    The purpose of this study was to evaluate the outcomes of the Boston type 1 keratoprosthesis (Kpro-1) in eyes with failed keratoplasty. A retrospective review was performed of every patient treated with a Kpro-1 at a tertiary eye care center between January 1, 2008 and July 1, 2013. Eyes with a failed keratoplasty originally performed for corneal edema, trauma, or keratoconus were included in the statistical analysis. The main outcome measures were visual outcome, prosthesis retention, and postoperative complications. Twenty-four eyes met the inclusion criteria, including 13 eyes with corneal edema, 8 eyes with trauma, and 3 eyes with keratoconus. After a mean follow-up period of 28.9 months (range 7-63 months), the median best corrected visual acuity (BCVA) was 20/125. The BCVA was ≥20/40 in 4 (16.7 %) eyes, ≥20/70 in 9 (37.5 %) eyes, and ≥20/200 in 14 (58.3 %) eyes. Overall, the postoperative BCVA improved in 17 (70.9 %) eyes, was unchanged in 3 (12.5 %) eyes, and was worse in 4 (16.7 %) eyes. The initial Kpro-1 was retained in 22 (91.7 %) eyes, and was successfully repeated in the other 2 eyes. One or more serious prosthesis- or sight-threatening complications occurred in 8 (33.3 %) eyes. These included 1 case of wound dehiscence leading to prosthesis extrusion, 1 case of fungal keratitis leading to prosthesis extrusion, 4 cases of endophthalmitis, and 5 retinal detachments. The Boston Kpro-1 is associated with an excellent prognosis for prosthesis retention and satisfactory visual improvement in eyes with previous failed keratoplasty. PMID:25975459

  1. A Two-Piece Microkeratome-Assisted Mushroom Keratoplasty Improves the Outcomes and Survival of Grafts Performed in Eyes with Diseased Stroma and Healthy Endothelium (An American Ophthalmological Society Thesis)

    PubMed Central

    Busin, Massimo; Madi, Silvana; Scorcia, Vincenzo; Santorum, Paolo; Nahum, Yoav

    2015-01-01

    Purpose: To test the hypothesis that a new microkeratome-assisted penetrating keratoplasty (PK) technique employing transplantation of a two-piece mushroom-shaped graft may result in better visual outcomes and graft survival rates than those of conventional PK. Methods: Retrospective chart review of 96 eyes at low risk and 76 eyes at high risk for immunologic rejection (all with full-thickness central corneal opacity and otherwise healthy endothelium) undergoing mushroom PK between 2004 and 2012 at our Institution. Outcome measures were best-corrected visual acuity (BCVA), refraction, corneal topography, endothelial cell density, graft rejection, and survival probability. Results: Five years postoperatively, BCVA of 20/40 and 20/20 was recorded in 100% and over 50% of eyes, respectively. Mean spherical equivalent of refractive error did not vary significantly over a 5-year period; astigmatism averaged always below 4 diopters, with no statistically significant change over time, and was of the regular type in over 90% of eyes. Endothelial cell density decreased to about 40% of the eye bank count 2 years after mushroom PK and did not change significantly thereafter. Five years postoperatively, probabilities of graft immunologic rejection and graft survival were below 5% and above 95%, respectively. There was no statistically significant difference in endothelial cell loss, graft rejection, and survival probability between low-risk and high-risk subgroups. Conclusions: Refractive and visual outcomes of mushroom PK compare favorably with those of conventional full-thickness keratoplasty. In eyes at high risk for immunologic rejection, mushroom PK provides a considerably higher probability of graft survival than conventional PK. PMID:26538771

  2. Liquid-phase penetration under unsteady in-cylinder conditions: Soy- and Cuphea-derived biodiesel fuels vs. conventional diesel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accelerated dilution of engine-lubrication oil is a significant potential issue when fueling with biodiesel. Biodiesel produced from some feedstocks is less volatile than conventional diesel, which makes wall-impingement of liquid fuel more likely, a problem that could be exacerbated by advanced in...

  3. Traumatic graft dehiscence after anterior lamellar keratoplasty.

    PubMed

    Prasher, Pawan; Muftuoglu, Orkun; Mootha, V Vinod

    2009-02-01

    A 64-year-old man underwent anterior lamellar keratoplasty using the Melles technique for corneal scar secondary to healed bacterial keratitis in the left eye. Two months postoperatively, the patient presented with blurry vision in the left eye after a fall in the bathroom. The uncorrected visual acuity was 20/400 in the left eye, and the external examination showed periorbital swelling with ecchymosis. Slit-lamp examination revealed an absent graft, a circular crater in the center, and a fragment of suture on the temporal edge of the crater. The Seidel test was negative, and there was no sign of infection. The anterior segment optical coherence tomography showed intact residual stroma with slight forward protrusion. The patient underwent repeat anterior lamellar corneal transplantation with improvement in uncorrected visual acuity of 20/100 and best spectacle-corrected visual acuity of 20/70 in the left eye 3 months postoperatively. PMID:19158577

  4. Evolution of keratoplasty: from darkness to light.

    PubMed

    Bhartiya, Shibal; Gupta, Noopur

    2012-10-01

    The story of the evolution of corneal grafting reads like a modem day epic: Complete with a cast of larger than life heroes, brilliant and heroic feats, inspired by the mundane. The history is also peppered with dismal, heart rending failures, foolhardy ventures, and the ultimate triumph of the indomitable human spirit over all odds. This review aims to highlight the significant milestones in the rich history of corneal transplantation, and to pay tribute to the many inspired and dedicated pioneers in this field for their perseverance and superior wisdom. It is also a salute and memorial to the patients who reposed their trust in the corneal surgeons, subjecting themselves to the trauma of surgery, often with less than optimal results. It was their collective, relentless toil and dynamic vision which has resulted in the state of the art surgical techniques which are the basis of modern day keratoplasty. PMID:23738408

  5. Alternaria keratitis after deep anterior lamellar keratoplasty.

    PubMed

    Naik, Mekhla; Mohd Shahbaaz; Sheth, Jay; Sunderamoorthy, S K

    2014-01-01

    To describe a case of Alternaria keratitis in a 30-year-old male patient who presented with bilateral vascularised central corneal opacity and underwent deep anterior lamellar keratoplasty (DALK) in the left eye. Patient was treated for recurrent epithelial defect with a bandage contact lens in the follow-up visits after DALK. Subsequently, patient presented with pigmented fungal keratitis, which on culture examination of the corneal scrapping demonstrated Alternaria species. Patient had to undergo a repeat DALK as the keratitis did not resolve with medical therapy alone. Patient did not have a recurrence for 11 months following the regraft. This case report highlights the importance of considering the Alternaria species as a possibile cause of non-resolving fungal keratitis after DALK. PMID:24669155

  6. Phototherapeutic keratectomy for recurrent granular dystrophy in postpenetrating keratoplasty eyes

    PubMed Central

    Rathi, Varsha M; Taneja, Mukesh; Murthy, Somasheila I; Bagga, Bhupesh; Vaddavalli, Pravin Krishna; Sangwan, Virender S

    2016-01-01

    Purpose: The purpose is to assess the clinical and visual outcome after phototherapeutic keratectomy (PTK) procedure in eyes with prior penetrating keratoplasty (PKP) for granular corneal dystrophy (GCD) and the time of performance of repeat PTK for recurrence. Methods: PTK was performed for visually significant recurrence: A reduction in best-corrected visual acuity (BCVA) by >2 lines over BCVA before recurrence was considered as visually significant recurrence. Three eyes had amniotic membrane patch performed with PTK. The main outcome measures were a recurrence of GCD, clinical course, and visual outcome. Intervals between repeat PTK procedures were noted. Results: Six patients (n = 10 eyes; males: 4, mean age 39 ± 13.97 years) underwent PTK. The mean pachymetry before first PTK was 527.1 ± 34 microns. The mean duration between PKP and first PTK was 85.1 months (range: 37–108 months). Two and three PTK procedures were done for seven and five eyes, respectively. Mean duration between first and second and second and third PTK was 62.12 ± 34.41 and 42.8 ± 13.54 months respectively. The average cut depth was 43.66 ± 19.57, 75 ± 43.30 and 39 ± 19.79 microns after the first, second and third PTK procedures, respectively. All eyes had a corneal haze. Prefirst PTK mean BCVA was 20/200 and improved significantly after the first two PTK procedures to 20/40 and after the third PTK procedure to 20/32 (P < 0.001). Five eyes had hyperopia. One acute graft rejection was managed successfully at 5 months with medical therapy. Conclusion: Multiple PTK procedures can be performed safely with improved visual acuity in grafts without compromising graft survival. PMID:27050350

  7. Holographic neural networks versus conventional neural networks: a comparative evaluation for the classification of landmine targets in ground-penetrating radar images

    NASA Astrophysics Data System (ADS)

    Mudigonda, Naga R.; Kacelenga, Ray; Edwards, Mark

    2004-09-01

    This paper evaluates the performance of a holographic neural network in comparison with a conventional feedforward backpropagation neural network for the classification of landmine targets in ground penetrating radar images. The data used in the study was acquired from four different test sites using the landmine detection system developed by General Dynamics Canada Ltd., in collaboration with the Defense Research and Development Canada, Suffield. A set of seven features extracted for each detected alarm is used as stimulus inputs for the networks. The recall responses of the networks are then evaluated against the ground truth to declare true or false detections. The area computed under the receiver operating characteristic curve is used for comparative purposes. With a large dataset comprising of data from multiple sites, both the holographic and conventional networks showed comparable trends in recall accuracies with area values of 0.88 and 0.87, respectively. By using independent validation datasets, the holographic network"s generalization performance was observed to be better (mean area = 0.86) as compared to the conventional network (mean area = 0.82). Despite the widely publicized theoretical advantages of the holographic technology, use of more than the required number of cortical memory elements resulted in an over-fitting phenomenon of the holographic network.

  8. Hydrophilic Acrylic Intraocular Lens Opacification after Descemet Stripping Automated Endothelial Keratoplasty

    PubMed Central

    Norouzpour, Amir; Zarei-Ghanavati, Siamak

    2016-01-01

    Purpose: To report hydrophilic acylic intraocular lens (IOL) opacification after Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) in an eye with multiple prior intraocular surgeries and iatrogenic aniridia. Case Report: A 34-year-old woman with history of penetrating keratoplasty (PKP) for advanced keratoconus and subsequent Urrets-Zavalia Syndrome (UZS) underwent phacoemulsification and hydrophilic acrylic IOL implantation for her cataract. In order to control post-PKP glaucoma, multiple glaucoma surgeries including two glaucoma drainage implants were performed. As the original corneal graft failed, the patient subsequently underwent re-PKP. Four years later, she underwent DSAEK for treatment of the second graft failure. Ten months after DSAEK, a double semi-circular pattern of IOL opacification was observed on the anterior surface of the IOL. The patient did not report any complaints and we decided not to exchange the IOL. Conclusion: In an eye with UZS and iatrogenic aniridia, IOL opacification may result from direct contact between the IOL surface and exogenous air. Aniridia can be a risk factor for development of IOL opacification after DSAEK. Further studies are required to confirm this hypothesis. PMID:27413506

  9. Improved method of laser thermal keratoplasty to overcome presbyopia

    NASA Astrophysics Data System (ADS)

    Rodgers, K. Jonathan; Glen, Harry G.; Salz, James J.; Maguen, Ezra; Berry, Michael J.

    2011-03-01

    Optimal keratoplasty (Opti-K®) is an improved method of laser thermal keratoplasty (LTK) that is performed using a continuous wave (cw) laser for anterior stromal heating together with a sapphire applanation window for epithelial protection. Opti-KK® has been used to improve uncorrected near visual acuity (UNVA) in emmetropic presbyopes while retaining or even improving uncorrected distance visual acuity (UDVA) - a truly optimal result that is linked to corneal multifocality produced by optimal keratoplasty. Opti-KK® has also been used to improve both UDVA and UNVA in hyperopic presbyopes. The safety and effectiveness of Opti-KK® have been evaluated in a Nassau clinical study and in an ongoing U.S. Clinical Trial. The procedure is noninvasive, simple, rapid, comfortable and repeatable. Although Opti-KK® VA improvements are temporary, treatments can be repeated whenever needed to maintain "vision rejuvenationK®".

  10. Contact Lens Visual Rehabilitation in Keratoconus and Corneal Keratoplasty

    PubMed Central

    Ozkurt, Yelda; Atakan, Mehmet; Gencaga, Tugba; Akkaya, Sezen

    2012-01-01

    Keratoconus is the most common corneal distrophy. It's a noninflammatory progressive thinning process that leads to conical ectasia of the cornea, causing high myopia and astigmatism. Many treatment choices include spectacle correction and contact lens wear, collagen cross linking, intracorneal ring segments implantation and finally keratoplasty. Contact lenses are commonly used to reduce astigmatism and increase vision. There are various types of lenses are available. We reviewed soft contact lenses, rigid gas permeable contact lenses, piggyback contact lenses, hybrid contact lenses and scleral-semiscleral contact lenses in keratoconus management. The surgical option is keratoplasty, but even after sutur removal, high astigmatism may stil exists. Therefore, contact lens is an adequate treatment option to correct astigmatism after keratoplasty. PMID:22292112

  11. Intracameral air following pneumatic noncontact tonometry in a recently post–perforating keratoplasty patient

    PubMed Central

    Vámosi, Péter

    2014-01-01

    Purpose The purpose of this report is to highlight the potential risk of noncontact tonometry after routine uncomplicated penetrating keratoplasty (PK). Case report After uncomplicated PK for keratoconus, routine noncontact tonometry was performed on the second postoperative day. In spite of the adequately closed wound and the tight suture, temporary wound dehiscence occurred, and two-thirds of the anterior chamber was occupied by air. The running suture remained intact, and the Seidel test was negative. One week postoperatively, the patient’s corrected distance visual acuity was 0.4 (0.4 logMAR), and the air bubble had absorbed. Conclusion This is the first report to conclude that noncontact tonometry may not be sufficiently safe in the early postoperative period in normal PK cases. To prevent possible wound opening, we suggest the use of other tonometry methods during the first several months after PK. PMID:24790404

  12. Non-Descemet Stripping Automated Endothelial Keratoplasty for Bullous Keratopathy in Buphthalmic Eye

    PubMed Central

    Hirano, Koji; Kachi, Shu; Matsuura, Masako; Kawase, Kazuhide

    2016-01-01

    Purpose To report the 2-year follow-up findings in a patient with buphthalmic bullous keratopathy (BK) who was successfully treated with non-Descemet stripping automated endothelial keratoplasty (nDSAEK). Methods A 39-year-old man had an endothelial graft of 8.0 mm diameter placed uneventfully using the nDSAEK method for phakic BK with buphthalmos of the left eye. He had had a penetrating keratoplasty in the right eye due to aphakic BK 5 years earlier, which, however, resulted in the invasion of blood vessels and graft failure. Since the left eye was phakic, Descemetorhexis was not performed because the instruments might touch the crystalline lens. The best-corrected visual acuity (BCVA), intraocular pressure (IOP), and endothelial cell density (ECD) were determined at 2 weeks, and at 1, 3, 6, 12, 18 and 24 months after nDSAEK. Results Twenty-four months after nDSAEK, his left cornea and lens remained clear, and the decimal BCVA was 0.8. However, the ECD of the graft had decreased from 2,274 cells/mm2 before nDSAEK to 539 cells/mm2 24 months after the surgery, and the rate of decrease appeared to be slightly faster than that of former reports. An IOP of $1003e;30 mm Hg was recorded at around 2 months after the surgery, but was well controlled by tapering the topical steroids and the addition of topical brinzolamide and latanoprost. Conclusion Our findings show that nDSAEK can be successfully used to treat buphthalmic BK. We recommend that nDSAEK be considered especially in phakic eyes with a smooth posterior surface around the pupillary area. PMID:27462256

  13. Pachymetry-guided intrastromal air injection ("pachy-bubble") for deep anterior lamellar keratoplasty.

    PubMed

    Ghanem, Ramon C; Ghanem, Marcielle A

    2012-09-01

    To evaluate an innovative technique for intrastromal air injection to achieve deep anterior lamellar keratoplasty (DALK) with bare Descemet membrane (DM). Thirty-four eyes with anterior corneal pathology, including 27 with keratoconus, underwent DALK. After 400 μm trephination with a suction trephine, ultrasound pachymetry was performed 0.8 mm internally from the trephination groove in the 11 to 1 o'clock position. In this area, a 2-mm incision was created, parallel to the groove, with a micrometer diamond knife calibrated to 90% depth of the thinnest measurement. A cannula was inserted through the incision and 0.5 mL of air was injected to dissect the DM from the stroma. After peripheral paracentesis, anterior keratectomy was carried out to bare the DM. A 0.25-mm oversized graft was sutured in place. Overall, 94.1% of eyes achieved DALK. Bare DM was achieved in 30 eyes, and a pre-DM dissection was performed in 2 eyes. Air injection was successful in detaching the DM (achieving the big bubble) in 88.2% of the eyes. In keratoconus eyes, the rate was 88.9%. All cases but one required a single air injection to achieve DM detachment. Microperforations occurred in 5 cases: 3 during manual layer-by-layer dissection after air injection failed to detach the DM, 1 during removal of the residual stroma after big-bubble formation, and 1 during the diamond knife incision. Two cases (5.9%) were converted to penetrating keratoplasty because of macroperforations. The technique was reproducible, safe, and highly effective in promoting DALK with bare DM. PMID:22367050

  14. A Method to Prepare a Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) Graft Using Donor Corneas With Narrow Scleral Rims

    PubMed Central

    Lin, Tzu-Yu; Hwang, Yih-Shiou; Ma, David Hui-Kang

    2015-01-01

    Abstract Donor corneas with narrow scleral rims are often disqualified for Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK), mainly because of fluid leak and low pressure when they are mounted onto an artificial anterior chamber (AAC). This report describes a novel method to tight-lock a donor cornea with a narrow scleral rim so that microkeratome cutting is possible, allowing a DSAEK procedure to be completed. A 50-year-old male suffering from Epstein–Barr virus (EBV) endotheliitis with resulting corneal edema in his left eye was the subject of this study. His best corrected visual acuity (BCVA) was 20/600. The patient underwent a DSAEK procedure; however, the microkeratome cutting of the donor cornea initially failed due to its narrow scleral rim, which caused the balance salt solution (BSS) to leak out of the AAC. A doughnut-shaped cushion was made from a surgical glove, which enabled a tight lock of the cornea to the AAC, enabling the chamber pressure to be raised and the microkeratome cutting to be completed. A subsequent DSAEK procedure was performed uneventfully. Postoperatively, the patient received oral valganciclovir 450 mg b.i.d. to prevent EBV recurrence. The graft remained clear at 5 months post-op, and the patient's BCVA improved to 6/7.5. His endothelial count was 1830, which was ∼ 79% of the original value. Inserting a self-made cushion can enable donor corneas with narrow scleral rims to be used in DSAEK procedures and avoids unwanted switching from endothelial keratoplasty to penetrating keratoplasty (PKP). PMID:26426641

  15. Deep Anterior Lamellar Keratoplasty Using Irradiated Acellular Cornea with Amniotic Membrane Transplantation for Intractable Ocular Surface Diseases

    PubMed Central

    Wee, Sung Wook; Choi, Sang Uk

    2015-01-01

    Purpose To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) when sterile gamma-irradiated acellular corneal tissues (VisionGraft) are used in combination with amniotic membrane transplantation (AMT) for intractable ocular surface diseases. Methods The medical records of fifteen patients who had DALK with AMT were retrospectively reviewed. Indications for surgery included ocular burn, bacterial keratitis, herpes simplex virus keratitis, corneal opacity with Stevens-Johnson syndrome, Mooren's ulcer, idiopathic myxoid degeneration of corneal stroma, and recurrent band keratopathy. DALK was performed using partial-thickness acellular corneal tissue and a temporary amniotic membrane patch was added at the end of the operation. Results All cases that underwent DALK with AMT became epithelialized within 2 postoperative weeks. Twelve patients showed favorable outcomes without graft rejection, corneal opacification, or neovascularization. The other three grafts developed corneal opacification and neovascularization, and required additional penetrating keratoplasty (PK). Unlike the results of previous PKs, there were no graft rejections and the graft clarity was well-maintained in these three cases for at least 8 months after PK. Conclusions DALK using sterile acellular corneal tissues in combination with AMT may be a good therapeutic strategy for treating intractable ocular surface diseases because of lowered immune rejection, fibroblast activation, and facilitation of epithelialization. Furthermore, DALK can help stabilize the ocular surface, prolong graft survival, and may allow better outcomes when combined with subsequent PK. PMID:25829823

  16. Severe penetrating ocular injury from ninja stars in two children.

    PubMed

    Jeng, B H; Steinemann, T L; Henry, P; Brodsky, M C

    2001-01-01

    The authors describe two cases of penetrating ocular trauma in children resulting from ninja stars. In the first case, despite a scleral laceration, loss of iris tissue, and a vitreous hemorrhage, the child had a good result with a final best corrected visual acuity of 20/20. Unfortunately, the child in the second case did not fare as well. In this case, the child suffered a large corneal laceration and traumatic cataract. He ultimately required a penetrating keratoplasty, and he is currently being treated for amblyopia, strabismus, and elevated intraocular pressures. His best corrected visual acuity is 20/70. PMID:11475403

  17. The Penetration Behavior of an Annular Gas-Solid Jet Impinging on a Liquid Bath: Comparison with a Conventional Circular Jet

    NASA Astrophysics Data System (ADS)

    Park, Sung Sil; Dyussekenov, Nurzhan; Sohn, H. Y.

    2010-02-01

    The top-blow injection technique of a gas-solid mixture through a circular lance is used in the Mitsubishi Continuous Smelting Process. One of the inherent problems associated with this injection is the severe erosion of the hearth refractory below the lances. A new configuration of the lance to form an annular gas-solid jet rather than a circular jet was designed in the laboratory scale. With this new configuration, solid particles leave the lance at a much lower velocity than the gas, and the penetration behavior of the jet is significantly different than with the circular lance in which the solid particles leave the lance at the same high velocity as the gas. The results of cold model tests using an air-sand jet issuing from a circular lance and an annular lance into a water bath showed that the penetration of the annular jet is much less sensitive to the variations in particle feed rate as well as gas velocity than that of the circular jet. Correlation equations for the penetration depth for both circular and annular jets show agreement among the experimentally obtained values.

  18. Histological changes and wound healing response following noncontact holmium: YAG laser thermal keratoplasty.

    PubMed Central

    Koch, D D

    1996-01-01

    PURPOSE: To evaluate acute histological changes and the induced wound healing response in corneal tissue following noncontact holmium:YAG laser thermal keratoplasty (LTK). METHODS: LTK using 10 pulses and a range of radiant energies was performed on 3 human corneas one day prior ro their removal at penetrating keratoplasty. Rabbit corneas were treated with 10-pulse and 5-pulse LTK and followed for up to 3 months. Tissues were studies with light and transmission electron microscopy and immunohistochemistry. RESULTS: The amount of acute tissue injury increased with increasing pulse radiant energy. In human corneas, changes in the irradiated zones included epithelial cell injury and death loss of fine filamentous structure in Bowman's layer, disruption of stromal lamallae, and keratocyte injury and death. In the rabbit corneas, similar acute changes were noted. By 3 weeks, epithelial hyperplasia and stromal contraction were present. Wound healing in the rabbit corneas included repair of the epithelial attachment complex, keratocyte activation, synthesis of type I collagen, partial restoration of stromal keratan sulfate and type VI collagen, and retrocorneal membrane formation. Compared to 10-pulse treatments, 5-pulse treatments produced less acute tissue injury and had more rapid restoration of normal stromal architecture. CONCLUSION: Noncontact LTK produces acute epithelial and stromal tissue changes and in rabbit corneas stimulates a brisk wound healing response. These changes could contribute to postoperative regression of induced refractive correction. Further work is required to determine if reductions in the magnitude of acute tissue injury and induced wound healing response will enhance the efficacy and stability of LTK. Images FIGURE 1A FIGURE 1B FIGURE 2A FIGURE 2B FIGURE 3A FIGURE 3B FIGURE 4A FIGURE 4B FIGURE 4C FIGURE 4D FIGURE 5A FIGURE 5B FIGURE 5C FIGURE 5D FIGURE 6A FIGURE 6B FIGURE 6C FIGURE 6D FIGURE 7A FIGURE 7B FIGURE 8A FIGURE 8B FIGURE 8C FIGURE

  19. [Corneal reinnervation after lamellar keratoplasty in comparison with epikeratophakia and photorefractive keratectomy].

    PubMed

    Böhm, A; Kohlhaas, M; Kliefoth, U; Draeger, J; Lombardi, M; Abbondanza, M; Zuppardo, M; Görne, M

    1994-10-01

    Corneal sensitivity was examined with the Draeger aesthesiometer in 8 patients after lamellar keratoplasty, 7 patients after epikeratophakia and 82 patients after photorefractive keratectomy. We examined 9 different points in each cornea. The corneal sensitivity of patients after lamellar keratoplasty was normal 1 year after operation. A correlation with the depth of the lamellar dissection was demonstrated. Patients with lamellar keratoplasty with pterygium showed a sensitivity decrease in the nasal parts of the lenticule even after one year. Three years after epikeratophakia the corneal center was still not sensitive. After photorefractive keratectomy of more than 10 D, corneal hyposensitivity was shown even 2 years after operation. PMID:7812096

  20. Hybrid Technique of Lamellar Keratoplasty (DMEK-S)

    PubMed Central

    Studeny, Pavel; Liehneova, Katerina; Vokrojova, Magdalena; Kuchynka, Pavel

    2013-01-01

    Purpose: To evaluate the outcomes of the hybrid technique of posterior lamellar keratoplasty (DMEK-S). Materials and Methods: 71 eyes of 55 patients enrolled in a single-center study underwent posterior lamellar keratoplasty with a hybrid lamella DMEK-S implanted using a solution implantation technique, owing to endothelial dysfunction. The outcome measures studied were visual acuity and endothelial cell density. Results: The rate of endothelial cell loss caused by surgery was 43.8%. During followups, we observed the stabilization of postoperative findings, or at minimum a very low rate of corneal endothelial cell loss. The UCDVA and BCDVA dramatically improved postoperatively. The rebubbling rate in our group of patients was 61.9%. We replaced the lamella due to its failure or malfunction in 17 patients (23.9%). Conclusion: In summary, DMEK-S combines the advantages of DSEK/DSAEK and DMEK. The central zone of bare Descemet's membrane and endothelium allows for very good visual outcomes, and the peripheral rim allows for better manipulation of the lamella during implantation. It is an effective method of treating the endothelial dysfunction of various etiologies, but the high complication rate needs to be addressed before widespread implementation of the technique in the future. PMID:23840937

  1. Ultrastructural analysis of the decellularized cornea after interlamellar keratoplasty and microkeratome-assisted anterior lamellar keratoplasty in a rabbit model.

    PubMed

    Hashimoto, Yoshihide; Hattori, Shinya; Sasaki, Shuji; Honda, Takako; Kimura, Tsuyoshi; Funamoto, Seiichi; Kobayashi, Hisatoshi; Kishida, Akio

    2016-01-01

    The decellularized cornea has received considerable attention for use as an artificial cornea. The decellularized cornea is free from cellular components and other immunogens, but maintains the integrity of the extracellular matrix. However, the ultrastructure of the decellularized cornea has yet to be demonstrated in detail. We investigated the influence of high hydrostatic pressure (HHP) on the decellularization of the corneal ultrastructure and its involvement in transparency, and assessed the in vivo behaviour of the decellularized cornea using two animal transplantation models, in relation to remodelling of collagen fibrils. Decellularized corneas were prepared by the HHP method. The decellularized corneas were executed by haematoxylin and eosin and Masson's trichrome staining to demonstrate the complete removal of corneal cells. Transmission electron microscopy revealed that the ultrastructure of the decellularized cornea prepared by the HHP method was better maintained than that of the decellularized cornea prepared by the detergent method. The decellularized cornea after interlamellar keratoplasty and microkeratome-assisted anterior lamellar keratoplasty using a rabbit model was stable and remained transparent without ultrastructural alterations. We conclude that the superior properties of the decellularized cornea prepared by the HHP method were attributed to the preservation of the corneal ultrastructure. PMID:27291975

  2. Ultrastructural analysis of the decellularized cornea after interlamellar keratoplasty and microkeratome-assisted anterior lamellar keratoplasty in a rabbit model

    PubMed Central

    Hashimoto, Yoshihide; Hattori, Shinya; Sasaki, Shuji; Honda, Takako; Kimura, Tsuyoshi; Funamoto, Seiichi; Kobayashi, Hisatoshi; Kishida, Akio

    2016-01-01

    The decellularized cornea has received considerable attention for use as an artificial cornea. The decellularized cornea is free from cellular components and other immunogens, but maintains the integrity of the extracellular matrix. However, the ultrastructure of the decellularized cornea has yet to be demonstrated in detail. We investigated the influence of high hydrostatic pressure (HHP) on the decellularization of the corneal ultrastructure and its involvement in transparency, and assessed the in vivo behaviour of the decellularized cornea using two animal transplantation models, in relation to remodelling of collagen fibrils. Decellularized corneas were prepared by the HHP method. The decellularized corneas were executed by haematoxylin and eosin and Masson’s trichrome staining to demonstrate the complete removal of corneal cells. Transmission electron microscopy revealed that the ultrastructure of the decellularized cornea prepared by the HHP method was better maintained than that of the decellularized cornea prepared by the detergent method. The decellularized cornea after interlamellar keratoplasty and microkeratome-assisted anterior lamellar keratoplasty using a rabbit model was stable and remained transparent without ultrastructural alterations. We conclude that the superior properties of the decellularized cornea prepared by the HHP method were attributed to the preservation of the corneal ultrastructure. PMID:27291975

  3. Scanning electron microscope and dye penetration test: comparison of root canal preparation with 15 F CO2 laser microprobe versus conventional method--in vivo study

    NASA Astrophysics Data System (ADS)

    Kesler, Gavriel; Koren, Rumelia; Kesler, Anat; Hay, Nissim; Gal, Rivka

    1999-05-01

    The study was conducted on 30 vital maxillary or mandibulary teeth destined for extraction due to periodontal problems. 21 were experimentally treated with pulsed CO2 laser delivered by a newly developed fiber and 9 teeth represented the control group. The micro probe is a flexible, hollow, metal fiber, 300 μm in diameter and 20 mm in length, coupled onto a handpiece, with the following radiation parameters: wavelength-10.6μm pulse duration-50m.sec; energy per pulses 0.25 joule; energy density-360 J/cm2 per pulse; power on tissue-5W. The laser group was divided into three, receiving 20, 40 or 60 pulses, respectively. On light microscopy: in all the control group cases, large amount of residual pulp tissue was seen, it was diminished in some of the low energy group and was totally eradicated in the high energy group. This was confirmed by the scanning electron microscope (SEM) examination. The dentin tubuli were partly occluded with the low energy levels and completely with the high levels, as shown by the high-speed centrifuge dye penetration test and by the SEM tests.

  4. Descemet's Stripping Automated Endothelial Keratoplasty Tissue Insertion Devices

    PubMed Central

    Khan, Salman Nasir; Shiakolas, Panos S.; Mootha, Venkateswara Vinod

    2015-01-01

    This review study provides information regarding the construction, design, and use of six commercially available endothelial allograft insertion devices applied for Descemet's stripping automated endothelial keratoplasty (DSAEK). We also highlight issues being faced in DSAEK and discuss the methods through which medical devices such as corneal inserters may alleviate these issues. Inserter selection is of high importance in the DSAEK procedure since overcoming the learning curve associated with the use of an insertion device is a time and energy consuming process. In the present review, allograft insertion devices were compared in terms of design, construction material, insertion technique, dimensions, incision requirements and endothelial cell loss to show their relative merits and capabilities based on available data in the literature. Moreover, the advantages/disadvantages of various insertion devices used for allograft insertion in DSAEK are reviewed and compared. The information presented in this review can be utilized for better selection of an insertion device for DSAEK. PMID:27051492

  5. Post conductive keratoplasty visualization of rabbit cornea by multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Lo, Wen; Wang, Tsung-Jen; Hu, Fung-Rong; Dong, Chen-Yuan

    2007-07-01

    Conductive keratoplasty (CK) is a new refractive surgery for presbyopia and hyperopia patients. By applying radio frequency current at the peripheral regions of cornea, collagen, the most abundant composition of corneal stroma, shrinks due to the heat generated. The shrinkage at the periphery alters the corneal architecture and achieves clearer focus for near vision. In this work we use multiphoton microscopy to observe the post surgery structure variation at both submicron resolution and over a large region within the tissue. Since collagen can be induced to generate strong second harmonic generation (SHG) signal, multiphoton excitation provide direct visualization of collagen orientation within corneal stroma. In addition, since the SHG intensity of collagen tissue deteriorates with increasing thermal damage [1-3], our methodology can be used to characterize the extent of corneal stroma damage from the CK procedure. Finally, the influence of CK on the morphology and distribution of keratocytes can also be investigated by detecting multiphoton excited autofluorescence from the cells.

  6. [Triple Descemet membrane endothelial keratoplasty : Indications, variations and results].

    PubMed

    Girbardt, C; Wiedemann, P; Nestler, A

    2016-03-01

    When Descemet membrane endothelial keratoplasty (DMEK) is indicated in patients with phakic eyes, a combination with phacoemulsification and intraocular lens implantation in one sitting should be considered as a triple DMEK. The best possible preoperative deswelling of the cornea should be strived for in order to allow sufficient viewing conditions for the individual stages of cataract surgery. Furthermore, technical details, e.g. regulation of pupillary width also must be considered. The power of the intraocular lens has to be adjusted in order to compensate for the shift of refraction towards hyperopic values induced by DMEK surgery. A rapid and clear improvement in visual acuity can normally be achieved after a triple DMEK. There seem to be no disadvantages compared with a two-stage procedure for DMEK and cataract surgery. PMID:26857142

  7. Femtosecond Laser Assisted Deep Anterior Lamellar Keratoplasty Outcomes and Healing Patterns Compared to Manual Technique

    PubMed Central

    Alio, Jorge L.; Abdelghany, Ahmed A.; Barraquer, Rafael; Hammouda, Laila M.; Sabry, Ahmed M.

    2015-01-01

    The purpose of the study is to report the visual, refractive, and wound healing pattern outcomes of femtosecond assisted deep anterior lamellar keratoplasty (DALK) compared to the conventional manual technique. DALK was performed on 50 eyes of 47 advanced keratoconus patients. The patients were divided into two groups, 25 eyes each, depending on whether femtosecond assisted or manual DALK technique was performed for the side cut of the procedure only. Patients were followed up at 1 month, 6 months, and 1 year for visual acuity, clinical refraction, corneal cylinder, date of suture removal, and side cut corneal healing pattern according to new grading classification of the side cut scar (Grade 0 = transparent scar, 1 = faint healing opacity, 2 = evident healing opacity, 3 = significant opacity with some cosmetic imbalance, and 4 = highly significant opacity with very significant cosmetic imbalance). Outcomes are reported at one year. In conclusion, femtosecond assisted and manual DALK show comparable visual and refractive outcomes but femtosecond assisted DALK shows more evident corneal wound healing patterns at the side cut. This observation may indicate that an activated cornea wound healing might allow earlier suture removal when femtosecond technology is used to perform the side cut for DALK. PMID:26557663

  8. A Biodegradable, Sustained-Released, Prednisolone Acetate Microfilm Drug Delivery System Effectively Prolongs Corneal Allograft Survival in the Rat Keratoplasty Model

    PubMed Central

    Liu, Yu-Chi; Peng, Yan; Lwin, Nyein Chan; Venkatraman, Subbu S.

    2013-01-01

    Frequent and long-term use of topical corticosteroids after corneal transplantation is necessary to prevent graft rejection. However, it relies heavily on patient compliance, and sustained therapeutic drug levels are often not achieved with administration of topical eye drops. A biodegradable drug delivery system with a controlled and sustained drug release may circumvent these limitations. In this study, we investigated the efficacy of a prednisolone acetate (PA)-loaded poly (d,l-lactide-co-ε-caprolactone) (PLC) microfilm drug delivery system on promoting the survival of allogeneic grafts after penetrating keratoplasty (PK) using a rat model. The drug release profiles of the microfilms were characterized (group 1). Subsequently, forty-eight PK were performed in four experimental groups: syngeneic control grafts (group 2), allogeneic control grafts (group 3), allogeneic grafts with subconjunctivally-implanted PA microfilm (group 4), and allogeneic grafts with PA eye drops (group 5; n = 12 in each). PA-loaded microfilm achieved a sustained and steady release at a rate of 0.006–0.009 mg/day, with a consistent aqueous drug concentration of 207–209 ng/ml. The mean survival days was >28 days in group 2, 9.9±0.8 days in group 3, 26.8±2.7 days in group 4, and 26.4±3.4 days in group 5 (P = 0.023 and P = 0.027 compared with group 3). Statistically significant decrease in CD4+, CD163+, CD 25+, and CD54+ cell infiltration was observed in group 4 and group 5 compared with group 3 (P<0.001). There was no significant difference in the mean survival and immunohistochemical analysis between group 4 and group 5. These results showed that sustained PA-loaded microfilm effectively prolongs corneal allograft survival. It is as effective as conventional PA eye drops, providing a promising clinically applicable alternative for patients undergoing corneal transplantation. PMID:23940573

  9. Personalised lamellar keratoplasty and keratopigmentation in Asian corneal leucoma patients

    PubMed Central

    Liu, Xin; Shen, Jun-Hui; Zhou, Qi; Liu, Zhen-Xing; Tang, Shen-Fei; Chen, Ran-Ran; Sui, Gui-Qin; Bi, Yan-Long

    2015-01-01

    Objective: To describe a personalised lamellar keratoplasty (LK) associated with the keratopigmentation (KTP) technique for corneal leucoma among Asian patients. Methods: This report was a non-randomised, retrospective clinical study performed in 32 consecutive eyes of 32 patients to improve cosmetic appearance. Twenty-two patients underwent LK combined with KTP, either by intralamellar or superficial route. Ten patients underwent the single personalised keratopigmentation method. The subjective and objective cosmetic results, ocular irritation, colour fading, neovascularisation formation and incidence of immune rejection were evaluated until three years after surgery. Results: No complications occurred, and the corneal leucoma was successfully stained with India ink in all 32 patients. Most of the patients showed good cosmetic appearance. Pain, conjunctival congestion, corneal edema and foreign body sensation disappeared gradually within two to three weeks after surgery in all patients. Graft swelling, non-healing, or detaching was not observed during follow-up. However, two patients had slight opacity three years after LK. Colour fading was observed in one patient who underwent intralamellar corneal staining 10 months after surgery. Re-staining was performed. Conclusion: KTP combined with personalised LK is an effective personalised technique that presents long-standing colour staining and good cosmetic efficacy. PMID:26309607

  10. OPTICS OF CONDUCTIVE KERATOPLASTY: IMPLICATIONS FOR PRESBYOPIA MANAGEMENT

    PubMed Central

    Hersh, Peter S

    2005-01-01

    Purpose To define the corneal optics of conductive keratoplasty (CK) and assess the clinical implications for hyperopia and presbyopia management. Methods Four analyses were done. (1) Multifocal effects: In a prospective study of CK, uncorrected visual acuity (UCVA) for a given refractive error in 72 postoperative eyes was compared to control eyes. (2) Surgically induced astigmatism (SIA): 203 eyes were analyzed for magnitude and axis of SIA. (3) Higher-order optical aberrations: Corneal higher-order optical aberrations were assessed for 36 eyes after CK and a similar patient population after hyperopic laser in situ keratomileusis (LASIK). (4) Presbyopia clinical trial: Visual acuity, refractive result, and patient questionnaires were analyzed for 150 subjects in a prospective, multicenter clinical trial of presbyopia management with CK. Results (1) 63% and 82% of eyes after CK had better UCVA at distance and near, respectively, than controls. (2) The mean SIA was 0.23 diopter (D) steepening at 175° (P < .001); mean magnitude was 0.66 D (SD, 0.43 D). (3) After CK, composite fourth- and sixth-order spherical aberration increased; change in (Z12) spherical aberration alone was not statistically significant. When compared to hyperopic LASIK, there was a statistically significant increase in composite fourth- and sixth-order spherical aberration (P < .01) and spherical aberration (Z12) alone (P < .02); spherical aberration change was more prolate after CK. (4) After the CK monovision procedure, 80% of patients had J3 or better binocular UCVA at near; 84% of patients were satisfied. Satisfaction was associated with near UCVA of J3 or better in the monovision eye (P = .001) and subjectively good postoperative depth perception (P = .038). Conclusions CK seems to produce functional corneal multifocality with definable introduction of SIA and higher-order optical aberrations, and development of a more prolate corneal contour. These optical factors may militate toward

  11. Regression of Urrets-Zavalia Syndrome After Deep Lamellar Keratoplasty for Keratoconus: A Case Study

    PubMed Central

    Spadea, Leopoldo; Viola, Mariangela; Viola, Giovanna

    2008-01-01

    We report a case of pharmacologic regression of Urrets-Zavalia syndrome, following deep lamellar keratoplasty for severe keratoconus. Sympatholytic and parasympathomimetic drops were administered and a progressive reduction of mydriasis and restoring of pupillary kinetics were observed. Four years after surgery, it was resulting in only slight residual anisocoria. PMID:19516912

  12. ENDOTHELIAL KERATOPLASTY: CLINICAL OUTCOMES IN THE TWO YEARS FOLLOWING DEEP LAMELLAR ENDOTHELIAL KERATOPLASTY (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS)

    PubMed Central

    Terry, Mark A.

    2007-01-01

    Purpose To evaluate the clinical outcome of small-incision, deep lamellar endothelial keratoplasty (DLEK) for the treatment of endothelial dysfunction. Methods A prospective series of 79 eyes that underwent DLEK by a single surgeon was evaluated. Best spectacle-corrected visual acuity (BSCVA), refractive astigmatism, and central endothelial cell density (ECD) were measured preoperatively and at 6, 12, and 24 months. Results Data was available on 78 eyes (99%) at 6 months, 77 eyes (97%) at 1 year, and 79 eyes (100%) at 2 years. Mean BSCVA preoperatively of 20/71 improved to 20/42 by 6 months and remained stable. Eliminating eyes with known retinal disease, BSCVA of 20/40 or better was present in 60% (40 of 67) of eyes at 6 months, 74% (49 of 66) of eyes at 1 year, and 79% (53 of 68) of eyes at 2 years. Refractive astigmatism preoperatively was .91 ±.78 diopters and was unchanged by surgery over time with results at 6 months of 1.11 ±.76 (P = .052, power = .43), 1 year 1.04 ±.80 (P =.287, power = .06), and 2 years 1.10 ±.70 (P =.467, power = .22). The mean donor ECD preoperatively was 2819 ± 225 (2389 to 3385) cells/mm2, and this decreased by 26% at 6 months (2095 ± 380) (1097 to 2920) (P = .0001; 95% confidence interval [CI] = 643–809), 3% fewer at 1 year (2009 ± 393) (612 to 2723) (P = .054, power = .5), and 17% fewer at 2 years (1536 ± 547) (500 to 2546) (P < .001, 95% CI = 368–585). Complications included one primary graft failure and 4 dislocations into the anterior chamber. Conclusions DLEK provides improved vision and minimal refractive astigmatic change, but progressive ECD decrease over time is of concern. PMID:18427629

  13. Penetrating trauma

    PubMed Central

    Kuhajda, Ivan; Zarogoulidis, Konstantinos; Kougioumtzi, Ioanna; Huang, Haidong; Li, Qiang; Dryllis, Georgios; Kioumis, Ioannis; Pitsiou, Georgia; Machairiotis, Nikolaos; Katsikogiannis, Nikolaos; Papaiwannou, Antonis; Lampaki, Sofia; Zaric, Bojan; Branislav, Perin; Dervelegas, Konstantinos; Porpodis, Konstantinos

    2014-01-01

    Pneumothorax occurs when air enters the pleural space. Currently there is increasing incidence of road traffic accidents, increasing awareness of healthcare leading to more advanced diagnostic procedures, and increasing number of admissions in intensive care units are responsible for traumatic (non iatrogenic and iatrogenic) pneumothorax. Pneumothorax has a clinical spectrum from asymptomatic patient to life-threatening situations. Diagnosis is usually made by clinical examination and imaging techniques. In our current work we focus on the treatment of penetrating trauma. PMID:25337403

  14. Penetrating trauma.

    PubMed

    Kuhajda, Ivan; Zarogoulidis, Konstantinos; Kougioumtzi, Ioanna; Huang, Haidong; Li, Qiang; Dryllis, Georgios; Kioumis, Ioannis; Pitsiou, Georgia; Machairiotis, Nikolaos; Katsikogiannis, Nikolaos; Papaiwannou, Antonis; Lampaki, Sofia; Zaric, Bojan; Branislav, Perin; Dervelegas, Konstantinos; Porpodis, Konstantinos; Zarogoulidis, Paul

    2014-10-01

    Pneumothorax occurs when air enters the pleural space. Currently there is increasing incidence of road traffic accidents, increasing awareness of healthcare leading to more advanced diagnostic procedures, and increasing number of admissions in intensive care units are responsible for traumatic (non iatrogenic and iatrogenic) pneumothorax. Pneumothorax has a clinical spectrum from asymptomatic patient to life-threatening situations. Diagnosis is usually made by clinical examination and imaging techniques. In our current work we focus on the treatment of penetrating trauma. PMID:25337403

  15. Penetrant-Indication-Measuring Compass

    NASA Technical Reports Server (NTRS)

    Schaefer, Lloyd

    1991-01-01

    Modified drafting compass well suited to measurement of length of crack or width of area stained by penetrant-dye-inspection method. Equipped with any of variety of standard curved or straight pointed tips. Modification consists in coating tips with dye that fluoresces light pink under same ultraviolet inspection light causing penetrant dye to fluoresce yellow green. Used in locations inaccessible to conventional fluorescent comparator. Eliminates errors of optical distortion in comparator, also eliminates errors of interpolation.

  16. Development of a new superficial punch for Descemet's Membrane Endothelial Keratoplasty donor tissue preparation.

    PubMed

    Ruzza, Alessandro; Parekh, Mohit; Salvalaio, Gianni; Ferrari, Stefano; Ponzin, Diego

    2016-04-01

    Endothelial Keratoplasty (EK) is a corneal surgical procedure that allows a selective transplantation of the posterior layer of the cornea. Descemet's Membrane Endothelial Keratoplasty (DMEK) is one of the EK procedures in which the diseased Descemet's Membrane and the endothelium are replaced with a healthy donor tissue. To achieve this, the donor cornea is cut superficially from the endothelial side and the tissue can be separated using specific instruments like Pierse Notched, Acute or Fogla forceps. However, the pressure required to punch the superficial layer has always been a challenge and therefore a calibrated device to punch and excise the required superficial layer has been designed. This new model of punch will help to identify the peripheral edge of the DMEK lenticule which in turn helps to excise the tissue exclusively, further reducing the donor tissue wastage, as seen with the current tissue preparation methods. PMID:26305003

  17. Keratorefractive Effect of High Intensity Focused Ultrasound Keratoplasty on Rabbit Eyes

    PubMed Central

    Du, Zhiyu; Zhang, Dan; Zhang, Yu

    2016-01-01

    Purpose. To evaluate high intensity focused ultrasound (HIFU) as an innovation and noninvasive technique to correct presbyopia by altering corneal curvature in the rabbit eye. Methods. Eighteen enucleated rabbit eyes were treated with a prototype HIFU keratoplasty. According to the therapy power, these eyes were divided three groups: group 1 (1 W), group 2 (2 W), and group 3 (3 W). The change in corneal power was quantified by a Sirius Scheimpflug camera. Light microscopy (LM) and transmission electron microscopy (TEM) were performed to determine the effect on the corneal stroma. Results. In the treated eyes, the corneal curvature increases from 49.42 ± 0.30 diopters (D) and 48.00 ± 1.95 D before procedure to 51.37 ± 1.11 D and 57.00 ± 1.84 D after HIFU keratoplasty application in groups 1 and 3, respectively. The major axis and minor axis of the focal region got longer when the powers of the HIFU got increased; the difference was statistically significant (p < 0.05). LM and TEM showed HIFU-induced shrinkage of corneal stromal collagen with little disturbance to the underlying epithelium. Conclusions. We have preliminarily exploited HIFU to establish a new technique for correcting presbyopia. HIFU keratoplasty will be a good application prospect for treating presbyopia. PMID:27382486

  18. Descemet's Stripping Automated Endothelial Keratoplasty versus Descemet's Membrane Endothelial Keratoplasty in the Fellow Eye for Fuchs Endothelial Dystrophy: A Retrospective Study

    PubMed Central

    Bhandari, Vipul; Reddy, Jagdeesh K.; Relekar, Kirti; Prabhu, Vijayalakshmi

    2015-01-01

    Aim. To evaluate visual outcome and endothelial cell density (ECD) after Descemet's Membrane Endothelial Keratoplasty (DMEK) in comparison with Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) in the fellow eye for Fuchs endothelial dystrophy (FED). Design. Single-centre, retrospective case series. Methods. 30 eyes of 30 patients undergoing DMEK, who completed a 1-year follow-up, were compared with 30 fellow eyes which underwent DSAEK for bilateral FED. Main outcome measures studied included Best Corrected Visual Acuity (BCVA) and ECD during a 1-year follow-up period. Results. BCVA improved from 0.78 ± 0.35 logMAR, and 0.73 ± 0.31 logMAR before surgery to 0.22 ± 0.1 logMAR and 0.35 ± 0.12 logMAR 6 months after DMEK and DSEK, respectively (P < 0.001). At one year after surgery, the BCVA was maintained at 0.21 ± 0.12 logMAR and 0.34 ± 0.1 logMAR, respectively, after DMEK and DSAEK. A statistically better visual outcome was observed after DMEK compared to DSAEK (P < 0.05) in fellow eyes. Conclusions. DMEK provided better visual rehabilitation when compared to DSAEK. Nevertheless, there were no significant differences with regard to the ECD within a 1-year follow-up. PMID:26636101

  19. Spontaneous Corneal Clearance in the Presence of a Partially Detached Graft after Non-Descemet Stripping Automated Endothelial Keratoplasty

    PubMed Central

    Droutsas, Konstantinos; Lazaridis, Apostolos; Koutsandrea, Chrysanthi; Chatzistefanou, Klio I.; Moschos, Marilita M.; Sekundo, Walter

    2016-01-01

    Purpose To report the explantation of a detached and opaque donor disc as an alternative to secondary keratoplasty in a case of persistent graft detachment followed by spontaneous clearance of the recipient cornea after non-Descemet stripping automated endothelial keratoplasty (non-DSAEK). Results Four months after graft explantation, BSCVA was 0.5 and endothelial cell density (ECD) was 1,221 cells/m2. After 13 months, BSCVA was still 0.6 while ECD had fell to 800, and 2 years later, the endothelium decompensated. BSCVA was 0.3 and ECD was not measurable. Conclusions To our knowledge this is the first report of explantation of an endothelial graft as an alternative to re-keratoplasty in a case of spontaneous corneal clearance. This minimally invasive treatment may be considered in similar cases. However, due to the ongoing loss of endothelial cells after endothelial keratoplasty, a re-keratoplasty may still be needed in the long term PMID:27403133

  20. Common complications of deep lamellar keratoplasty in the early phase of the learning curve

    PubMed Central

    Hosny, Mohamed

    2011-01-01

    Purpose: To evaluate and record the common complications that face surgeons when they perform their first few series of deep lamellar keratoplasty and measures to avoid these. Setting: Dar El Oyoun Hospital, Cairo, Egypt. Methods: Retrospective study of the first 40 eyes of 40 patients carried out by two corneal surgeons working in the same center. All patients were planned to undergo a deep anterior lamellar keratoplasty using the big bubble technique. Twelve patients suffered from keratoconus while 28 patients had anterior corneal pathologies. Recorded complications were classified as either intraoperative or postoperative. Results: Perforation of Descemet’s membrane was the most common intraoperative complication. It occurred in nine eyes (22.5%): five eyes (12.5%) had microperforations while four eyes (10%) had macroperforations, three eyes (7.5%) had central perforations, and six eyes (15%) had peripheral perforations. Other complications included incomplete separation of Descemet’s membrane and remnants of peripheral stromal tissue. Postoperative complications included double anterior chamber which occurred in four eyes (10%) and Descemet’s membrane corrugations. Postoperative astigmatism ranged from 1.25 to 4.5 diopters with a mean of 2.86 diopters in the whole series, but in the six cases with identified residual stroma in the periphery of the host bed, the astigmatism ranged from 2.75 to 4.5 diopters with a mean of 3.62 diopters. Conclusion: Deep lamellar keratoplasty is sensitive to procedural details. Learning the common complications and how to avoid them helps novice surgeons to learn the procedure faster. PMID:21750612

  1. Femtosecond laser assisted design of sutureless intrastromal graft as an alternative to partial thickness keratoplasty

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Durkee, Heather; Pini, Roberto; Canovetti, Annalisa; Malandrini, Alex; Lenzetti, Ivo; Rubino, Pierangela; Leaci, Rosachiara; Neri, Alberto; Scaroni, Patrizia; Menabuoni, Luca; Macaluso, Claudio

    2014-02-01

    Minimally invasive laser assisted surgery in ophthalmology is continuously developing in order to find new surgical approaches, preserve patient tissue and improve surgical results in terms of cut precision, restoration of visual acuity, and invasiveness. In order to achieve these goals, the current approach in corneal transplant is lamellar keratoplasty, where only the anterior or posterior part of the patient's cornea is substituted depending on the lesion or pathology. In this work, we present a novel alternative approach: a case study of intrastromal sutureless transplant, where a portion of the anterior stroma of a donor cornea was inserted into the stroma of the recipient cornea, aiming to restore the correct thickness of the patient's cornea. The patient cornea was paracentrally thin, as the result of a trophic ulcer due to ocular pemphigoid. A discoid corneal graft from the anterior stroma of a donor eye was prepared: a femtosecond laser cut with a trapezoidal profile (thickness was 300 μm, minor and major basis were 3.00 and 3.50 mm, respectively). In the recipient eye, an intrastromal cut was also performed with the femtosecond laser using a specifically designed mask; the cut position was 275 μm in depth. The graft was loaded into an injector and inserted as an intrastromal presbyopic implant. The postoperative analysis evidenced a clear and stable graft that selectively restored corneal thickness in the thinned area. Intrastromal corneal transplant surgery is a minimally invasive alternative to anterior or posterior lamellar keratoplasty in select cases. We believe that Sutureless Intrastromal Laser Keratoplasty (SILK) could open up new avenues in the field of corneal transplantation by fully utilizing the potential and precision of existing lasers.

  2. [Corneal infiltrates after keratoplasty caused by tissue inclusions of corn starch glove powder. An intraoperative complication].

    PubMed

    Mittelviefhaus, H

    1993-12-01

    Corneal infiltrations after keratoplasty may be the first sign of postoperative infection. We report on our findings of unusual corneal infiltrations, which were caused by contamination of the corneal tissue with remnants of latex glove powder. The diagnosis was proved by the specific distribution pattern and the clinical course. Infiltrates of decreasing size were observed in the area of all four temporarily supporting single-stitch sutures of the transplant and at the first stitches of the permanent running corneal sutures. There is no treatment necessary, but the infiltrates have to be differentiated from infection. Improvement of operative habits and techniques can avoid this complication. PMID:8124042

  3. Current Concepts in the Management of Unique Post-keratoplasty Infections

    PubMed Central

    Schallhorn, Julie M.

    2015-01-01

    As corneal transplantation has evolved, the spectrum of post-surgical infection has changed and often presents a diagnostic and therapeutic challenge. Lamellar techniques hold the potential of improved outcomes and decreased post-operative complications, however, they create a lamellar interface, which is a potential space for sequestration of infectious organisms. In addition, while keratoprosthesis offers vision to patients who are poor candidates for traditional keratoplasty, infectious complications can be severe and sight threatening. Although antimicrobials remain the mainstay of treatment, definitive management often requires surgical intervention. PMID:26618075

  4. Observation on ultrastructure and histopathology of cornea following femtosecond laser-assisted deep lamellar keratoplasty for acute corneal alkaline burns

    PubMed Central

    Li, Wen-Jing; Hu, Yu-Kun; Song, Hui; Gao, Xiao-Wei; Zhao, Xu-Dong; Dong, Jing; Guo, Yun-Lin; Cai, Yan

    2016-01-01

    AIM To demonstrate the changes in ultrastructure and histopathology of the cornea in acute corneal alkaline burns after femtosecond laser-assisted deep lamellar keratoplasty. METHODS The New Zealand white rabbits treated with alkaline corneal burn were randomized into two groups, Group A (16 eyes) with femtosecond laser-assisted deep lamellar keratoplasty 24h after burn and Group B (16 eyes) without keratoplasty as controls. All eyes were evaluated with transmission electron microscopy (TEM) at 1, 2, 3, and 4wk follow-up, then all corneas were tested by hematoxylin and eosin staining histology. RESULTS The corneal grafts in Group A were transparent, while those in Group B showed corneal stromal edema and loosely arranged collagen fibers. One week after treatment, TEM revealed the intercellular desmosomes in the epithelial layers and intact non-dissolving nuclei in Group A. At week 4, the center of the corneas in Group A was transparent with regularly arranged collagen fibers and fibroblasts in the stroma. In Group B, squamous cells were observed on the corneal surface and some epithelial cells were detached. CONCLUSION Femtosecond laser-assisted deep lamellar keratoplasty can suppress inflammatory responses, prevent toxic substance-induced injury to the corneal endothelium and inner tissues with quicker recovery and better visual outcomes. PMID:27162716

  5. Big bubble deep anterior lamellar keratoplasty for management of deep fungal keratitis.

    PubMed

    Gao, Hua; Song, Peng; Echegaray, Jose J; Jia, Yanni; Li, Suxia; Du, Man; Perez, Victor L; Shi, Weiyun

    2014-01-01

    Objective. To evaluate the therapeutic effect of big bubble deep anterior lamellar keratoplasty (DALK) in patients with deep fungal keratitis. Methods.Consecutive patients who had DALK for deep fungal keratitis at Shandong Eye Hospital between July 2011 and December 2012 were included. In all patients, the infiltration depth was more than 4/5ths of the corneal thickness. DALK surgery was performed with bare Descemet membrane (DM) using the big bubble technique. Corrected distance visual acuity (CDVA), graft status, and intraoperative and postoperative complications were monitored. Results. Big bubble DALK was performed in 23 patients (23 eyes). Intraoperative perforation of the DM occurred in two eyes (8.7%) during stromal dissection. The patients received lamellar keratoplasty with an air bubble injected into the anterior chamber. Double anterior chamber formed in 3 eyes (13.0%). Mean CDVA of the patients without cataract, amblyopia, and fungal recurrence was improved from preoperative HM/20 cm-1.0 (LogMAR) to 0.23 ± 0.13 (LogMAR) at the last followup (P < 0.01). Fungal recurrence was found in two patients (8.7%). Corneal stromal graft rejection was noted in one patient (4.3%). Conclusions. DALK using the big bubble technique seems to be effective and safe in the treatment of deep fungal keratitis unresponsive to medication. PMID:25105019

  6. Opacification of hydrophilic intraocular lenses after Descemet stripping automated endothelial keratoplasty

    PubMed Central

    Morgan-Warren, Peter J; Andreatta, Walter; Patel, Amit K

    2015-01-01

    Purpose Opacification of hydrophilic acrylic intraocular lenses (IOLs) is an emerging complication following Descemet stripping automated endothelial keratoplasty (DSAEK). We report six cases and review the current literature. Methods In this retrospective, noncomparative, observational case series, patients with IOL opacification after previous DSAEK surgery were identified from corneal clinic records. Case notes were reviewed for demographic details, indication for DSAEK, IOL model, incidence of rebubbling, and postoperative course. Results Six patients developed IOL opacification after DSAEK. All patients had Fuchs’ endothelial dystrophy and had previously received hydrophilic acrylic IOL models. Central anterior IOL opacification was noted in all six cases. Five cases (83%) had required rebubbling due to dislocated graft tissue, and one had an early postoperative intraocular pressure (IOP) rise. Five cases (83%) were managed conservatively, and one case with a failed graft underwent redo DSAEK and IOL exchange. Conclusion Repeated exposure to intracameral air, raised IOP, and other patient influences may be major etiological factors for IOL opacification after DSAEK. We advise avoiding hydrophilic acrylic IOL models in patients who may require future endothelial keratoplasty. PMID:25709389

  7. Anterior surface opacification of intraocular lenses after Descemet's stripping automated endothelial keratoplasty.

    PubMed

    Ní Mhéalóid, Áine; Fulcher, Tim; O'Keefe, Michael

    2015-01-01

    Descemet's stripping automated endothelial keratoplasty (DSAEK) is today recognised as the surgical procedure of choice for corneal endothelial dysfunction. The triple procedure (either staged or combined), whereby cataract surgery can be performed at the same time as endothelial keratoplasty, is well suited for patients with Fuch's endothelial dystrophy with decreased vision due to endothelial guttata, early stromal oedema and cataract formation. Recognised complications of DSAEK include donor graft detachment/dislocation, primary graft failure and pupillary block by air. Intraocular lens (IOL) opacification is a complication that is becoming apparent in patients who have undergone DSAEK and, to date, no definitive mechanism of such opacification has been discovered. Primary postoperative optic opacification of hydrophilic acrylic IOL designs has been attributed to the formation of calcium phosphate deposits. This has led to changes in lens designs, manufacturing processes and packaging. Secondary calcification is thought to be caused by environmental factors unrelated to the IOL model, such as breakdown of the blood-aqueous barrier. In this report, four cases of IOL anterior surface opacification are described in patients who required both cataract surgery and DSAEK. Only one case had cataract surgery and DSAEK performed concurrently, with the remainder having DSAEK performed at variable timeframes after cataract surgery. PMID:26677158

  8. Penetration of concrete targets

    SciTech Connect

    Forrestal, M.J.; Cargile, J.D.; Tzou, R.D.Y.

    1993-08-01

    We developed penetration equations for ogive-nosed projectiles that penetrated concrete targets after normal impact. Our penetration equations predict axial force on the projectile nose, rigid-body motion, and final penetration depth. For target constitutive models, we conducted triaxial material experiments to confining pressures of 600 MPa and curve-fit these data with a linear pressure-volumetric strain relation and with a linear Mohr-Coulomb, shear strength-pressure relation. To verify our penetration equations, we conducted eleven penetration experiments with 0.90 kg, 26.9-mm-diameter, ogive-nosed projectiles into 1.37-m-diameter concrete targets with unconfined compressive strengths between 32-40 MPa. Predictions from our penetration equation are compared with final penetration depth measurements for striking velocities between 280--800 m/s.

  9. Deep anterior lamellar keratoplasty in case of Hurler-Scheie syndrome.

    PubMed

    Sati, Alok; Ramappa, Muralidhar; Chaurasia, Sunita; Prasad, Sitarama M

    2014-01-01

    A 12-year-old boy with Hurler-Scheie syndrome (H/S syndrome) reported with reduced vision in both the eyes for past few years. Deep anterior lamellar keratoplasty (DALK) was performed for visual rehabilitation in his left eye. During surgery, the predescemet's plane was reached by meticulously dissecting the lamellar fibres using a manual technique. Histopathology of the dissected cornea showed the presence of numerous alcian blue positive deposits corroborating with the diagnosis of mucopolysaccharidosis (MPS). Postoperative course was uneventful. One year following surgery, the graft was clear and had a visual acuity of 20/50 with +1.00 170° - 0.75 refractive correction. Endothelial cell count, as measured by non-contact specular microscopy, was 2473.4 cells/mm(2). This case report highlights the application of DALK in a case of MPS-related corneal stromal opacification. PMID:24706723

  10. Fluorescent penetrant inspection

    NASA Technical Reports Server (NTRS)

    Sastri, Sankar

    1990-01-01

    The purpose of this experiment is to familiarize the student with fluorescent penetrant inspection and to relate it to classification of various defects. The penetrant method of nondestructive testing is a method for finding discontinuities open to the surface in solids and essentially nonporous bodies. The method employs a penetrating liquid which is applied over the surface and enters the discontinuity or crack. After the excess of penetrant has been cleaned from the surface, the penetrant which exudes or is drawn back out of the crack indicates the presence and location of a discontinuity. The experimental procedure is described.

  11. FAA fluorescent penetrant activities

    SciTech Connect

    Moore, D.G.; Larson, B.F.

    1997-11-01

    The Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) and the Center for Aviation Systems Reliability (CASR) are currently working to develop a liquid penetrant inspection (LPI) system evaluation capability that will support the needs of the penetrant manufacturers, commercial airline industry and the FAA. The main focus of this facility is to support the evaluation of penetrant inspection materials, penetrant systems and to apply resources to support industry needs. This paper discusses efforts to create such a facility and an initial project to produce fatigue crack specimens for evaluation of Type 1 penetrant sensitivities.

  12. Descemet-membrane endothelial keratoplasty in patients with retinal comorbidity-a prospective cohort study

    PubMed Central

    Spaniol, Kristina; Holtmann, Christoph; Schwinde, Jan-Hendrik; Deffaa, Sophia; Guthoff, Rainer; Geerling, Gerd

    2016-01-01

    AIM To investigate indications, surgical challenges, and outcome of Descemet-membrane endothelial keratoplasty (DMEK) in patients with retinal comorbidities (RC). METHODS In a prospective cohort study, 8 eyes of 8 DMEK-patients with known RC were compared to 38 eyes of 38 DMEK-patients without RC. The duration of surgery, the degree of difficulty graded by the surgeon, and the complications through DMEK-surgery were analyzed for each patient. The best-corrected visual acuity (BCVA), the endothelial cell count, the intraocular pressure, and the subjective satisfaction was evaluated after a 6-month follow-up. Data were compared applying the non-parametric Wilcoxon-, Chi-square- and Fisheŕs-exact-test with P≤0. 05 as level of significance. RESULTS RC-patients had dry age-related macular degeneration (n=4) or history of pars-plana vitrectomy (n=4). The main indication for DMEK was pain due to bullous keratopathy for the RC-patients (n=7, 88%) and visual impairment due to Fuchs endothelial keratoplasty for the non-RC-patients (n=33, 87%). The BCVA increased for both groups (P=0.01, P<0.001) and all corneas cleared. For the RC-patients, the subjective satisfaction improved significantly (P=0.02). Oil-filling and missing support of the vitreous body complicated surgery in vitrectomized eyes. CONCLUSION DMEK is a favorable technique to treat endothelial disorders even if patients suffer from a retinal comorbidity. By enhancing the corneal clarity, it enables retinal examination or intraocular surgery and increases the patientś satisfaction. However, in vitrectomized or silicone-oil filled eyes, the duration of surgery and degree of complexity are increased. An experienced surgeon should perform DMEK in these patients. Clinical trial registration number: DRKS00007566. PMID:27158608

  13. Refractive keratoplasty

    SciTech Connect

    Schwab, I.R. )

    1987-01-01

    This book contains 12 chapters. Some of the titles are: Perspectives on refractive surgery; Radial keratotomy; The refractive aspects of corneal transplantation; Wedge resection and relating incisions; Laser surgery of the cornea; and All plastic corneal lenses.

  14. Femtosecond laser-assisted keratoplasty combined with cataract extraction in a patient with keratoconus and oculocutaneous albinism

    PubMed Central

    Pásztor, Dorottya; Kolozsvári, Bence Lajos; Losonczy, Gergely; Fodor, Mariann

    2016-01-01

    In this study, we present a case of a 58-year-old male patient with oculocutaneous albinism, keratoconus, total cataract, and glaucoma originating from father-daughter incest. He underwent femtosecond laser-assisted keratoplasty with “open-sky” cataract extraction and posterior chamber intraocular lens implantation. One week after surgery his uncorrected visual acuity improved from hand motion to 20/200. Six months later corneal K values were 49.1 D in the flat and 50.0 D in the steep meridian. The graft had a central corneal thickness of 488 µm and was well fitted. The patient's quality of life improved substantially due to the surgery. To the best of our knowledge, this is the first report on the association of albinism with advanced keratoconus, total cataract, and glaucoma. Moreover, no previous report on femtosecond laser-assisted keratoplasty using VisuMax femtosecond laser system with “open-sky” cataract extraction is available in the literature. The VisuMax femtosecond laser-assisted keratoplasty ensures fast patient rehabilitation in such challenging cases. PMID:27146942

  15. Femtosecond laser-assisted keratoplasty combined with cataract extraction in a patient with keratoconus and oculocutaneous albinism.

    PubMed

    Pásztor, Dorottya; Kolozsvári, Bence Lajos; Losonczy, Gergely; Fodor, Mariann

    2016-03-01

    In this study, we present a case of a 58-year-old male patient with oculocutaneous albinism, keratoconus, total cataract, and glaucoma originating from father-daughter incest. He underwent femtosecond laser-assisted keratoplasty with "open-sky" cataract extraction and posterior chamber intraocular lens implantation. One week after surgery his uncorrected visual acuity improved from hand motion to 20/200. Six months later corneal K values were 49.1 D in the flat and 50.0 D in the steep meridian. The graft had a central corneal thickness of 488 µm and was well fitted. The patient's quality of life improved substantially due to the surgery. To the best of our knowledge, this is the first report on the association of albinism with advanced keratoconus, total cataract, and glaucoma. Moreover, no previous report on femtosecond laser-assisted keratoplasty using VisuMax femtosecond laser system with "open-sky" cataract extraction is available in the literature. The VisuMax femtosecond laser-assisted keratoplasty ensures fast patient rehabilitation in such challenging cases. PMID:27146942

  16. Session: Hard Rock Penetration

    SciTech Connect

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  17. Electrospun nanofibrous SF/P(LLA-CL) membrane: a potential substratum for endothelial keratoplasty

    PubMed Central

    Chen, Junzhao; Yan, Chenxi; Zhu, Mengyu; Yao, Qinke; Shao, Chunyi; Lu, Wenjuan; Wang, Jing; Mo, Xiumei; Gu, Ping; Fu, Yao; Fan, Xianqun

    2015-01-01

    Background Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF) has good biocompatibility but poor mechanical properties, while poly(l-lactic acid-co-ε-caprolactone) (P(LLA-CL)) has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL) can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty. Methods Five scaffolds containing different SF:P(LLA-CL) blended ratios (100:0, 75:25, 50:50, 25:75, 0:100) were manufactured. A human corneal endothelial (B4G12) cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test), cell proliferation (Ki-67, BrdU staining), and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction. Results Different blended ratios of scaffolds had different light transmittance properties. The 25:75 blended ratio membrane had the best transmittance among these scaffolds. All electrospun nanofibrous membranes showed improved speed of cell adherence when compared with the control group, especially when the P(LLA-CL) ratio increased. The 25:75 blended ratio membranes also had the highest cell proliferation. B4G12 cells could form a monolayer on all scaffolds, and most functional genes were also stably expressed on all

  18. Factors associated with graft survival and endothelial cell density after Descemet's stripping automated endothelial keratoplasty.

    PubMed

    Ishii, Nobuhito; Yamaguchi, Takefumi; Yazu, Hiroyuki; Satake, Yoshiyuki; Yoshida, Akitoshi; Shimazaki, Jun

    2016-01-01

    Postoperative endothelial cell loss leads to graft failure after corneal transplantation, and is one of the important issues for long-term prognosis. The objective of this study was to identify clinical factors affecting graft survival and postoperative endothelial cell density (ECD) after Descemet's stripping automated endothelial keratoplasty (DSAEK). A total of 198 consecutive Japanese patients (225 eyes) who underwent DSAEK were analysed using Cox proportional hazard regression and multiple linear regression models. The candidate factors included recipient age; gender; diagnosis; pre-existing iris damage state, scored based on its severity; the number of previous intraocular surgeries; graft ECD; graft diameter; simultaneous cataract surgery; surgeons experience; intraoperative iris damage; postoperative rebubbling; and graft rejection. Eyes with higher pre-existing iris damage score and more number of previous intraocular surgery had a significantly higher risk of graft failure (HR = 8.53; P < 0.0001, and HR = 2.66; P = 0.026, respectively). Higher pre-existing iris damage score, lower graft ECD, and smaller graft diameter were identified as significant predisposing factors for lower postoperative ECD. The results show that iris damage status before DSAEK may be clinically useful in predicting the postoperative course. Avoiding intraoperative iris damage, especially in eyes with low ECD can change the prognosis of future DSAEK. PMID:27121659

  19. Patch Grafting Using a Cryopreserved Descemet Stripping Automated Endothelial Keratoplasty Flap for Treating Corneal Perforation

    PubMed Central

    Okada, Arisa; Sano, Ichiya; Ikeda, Yoshifumi; Fujihara, Etsuko; Tanito, Masaki

    2016-01-01

    A 73-year-old woman with a corneal perforation of undetermined etiology was treated with corneal patch grafting. A residual partial-thickness corneal button obtained during a previous Descemet stripping automated endothelial keratoplasty (DSAEK) surgery and stored at −80°C in Optisol GS for 3 months was used as a patch graft. Five days postoperatively, the anterior chamber was reformed and the perforation was masked by the donor cornea. During the next several weeks, gradual displacement of the anterior edge of the donor cornea in the limbal direction occurred. Seven weeks postoperatively, further displacement of the donor cornea resulted in unmasking of the perforated area. At this time, the corneal defect was closed by stromal scar tissue and corneal epithelium. Five months postoperatively, best corrected visual acuity was 1.0 without marked astigmatism and intraocular pressure was 9 mm Hg in the left eye. From this case, we learned that cryopreserved DSAEK flaps stored longer than reported previously can be used as patch grafts to treat emergency conditions. Scar tissue can fill a corneal stromal defect 1 mm in diameter during temporary patch grafting for less than 2 months. PMID:27462245

  20. Optimising deep anterior lamellar keratoplasty (DALK) using intraoperative online optical coherence tomography (iOCT)

    PubMed Central

    Steven, Philipp; Le Blanc, Carolin; Lankenau, Eva; Krug, Marc; Oelckers, Stefan; Heindl, Ludwig M; Gehlsen, Uta; Huettmann, Gereon; Cursiefen, Claus

    2014-01-01

    Background/aims To describe the use of intraoperative online optical coherence tomography (iOCT) for improving deep anterior lamellar keratoplasty (DALK) surgery. Methods Retrospective case series of 6 eyes of 6 male patients with keratokonus, corneal dystrophy or herpetic stromal scars undergoing DALK were investigated using intraoperative optical coherence tomography and postsurgical image/video analysis. Main outcome measures were: visibility of surgical steps, especially, assessment of placement depth of injection needle, preparation of bare Descemet's membrane and drainage of interface fluid. Results iOCT enables real-time visualisation of all surgical steps of DALK procedure in all patients. Placement of air injection needle above Descemet's membrane was reliably monitored as was presence of bare Descemet's membrane and potential interface fluid. Conclusions iOCT assists with visualisation of injection needle placement and with assessment of bare Descemet's membrane as well as interface fluid during the DALK procedure. Overall iOCT may be a helpful device that supports surgeons in all steps of DALK procedure. PMID:24590554

  1. A novel method in preparation of acellularporcine corneal stroma tissue for lamellar keratoplasty

    PubMed Central

    Shao, Yi; Tang, Jing; Zhou, Yueping; Qu, Yangluowa; He, Hui; Liu, Qiuping; Tan, Gang; Li, Wei; Liu, Zuguo

    2015-01-01

    Our objective was to develop a novel lamellar cornealbiomaterial for corneal reconstruction.Theporcine acellular corneal stroma discs (ACSDs) were prepared from de-epithelized fresh porcine corneas (DFPCs) by incubation with 100% fresh human serum and additional electrophoresis at 4°C. Such manipulation removed theanterior corneal stromal cells without residual of DNA content and α-Galantigen. Human serum decellularizing activity on porcineanterior corneal stroma cells is through apoptosis, and associated with the presence of α-Gal epitopes in anterior stroma. ACSDs displayed similar optical, biomechanical properties and ultrastructure to DFPCs, and showed good histocompatibility in rabbit corneal stromal pockets and anterior chamber. Rabbit corneallamellar keratoplasty (LKP) using ACSDs showed no rejection and high transparency of cornea at 2 months after surgery. In vivo confocal laser scanning microscopy and immunostaining analysis showed complete re-epithelization and stromal cell in growth of ACSDs without inflammatory cell infiltration, new blood vessel ingrowth and excessive wound healing. In conclusion, this novel decellularization method may be valuable for preparation of xenogenic corneal tissue for clinical application, ACSDs resulted from this method may be served as a matrix equivalent for LKP in corneal xenotransplantation. PMID:26885261

  2. Superficial Anterior Lamellar Keratoplasty (SALK) for Trauma-induced Post Refractive Surgery Corneal Opacity

    PubMed Central

    Ganger, Anita; Tandon, Radhika; Vanathi, M.; Sagar, Pardeep

    2016-01-01

    Purpose: To report a case of post laser in situ keratomileusis (LASIK), nebulomacular corneal opacity following a trauma induced flap dehiscence and was managed with superficial anterior lamellar keratoplasty (SALK). Case Report: A 32-year-old female underwent LASIK 2.5 years back, with a postoperative unaided visual acuity (VA) of 6/6 in both eyes. She was involved in a road traffic accident and sustained blunt trauma to the right eye 5 months before. At the time of presentation, the VA was 1/60 in the right eye. Slit lamp examination revealed flap dehiscence, stromal scar and descemet folds in that eye. There was a small macular scar in the parafoveal area due to a resolved Berlin's edema. SALK was performed in the affected eye. Unaided VA of 6/36 was noted on post- operative day 1. After 4 weeks of SALK surgery, best corrected VA was 6/24. Conclusion: This case highlights that flap adhesions are not very strong even years after LASIK and SALK may be an effective treatment option for post refractive surgery corneal opacities. PMID:27621794

  3. Incidental central tear in Descemet membrane endothelial complex during Descemet membrane endothelial keratoplasty

    PubMed Central

    Mittal, Vikas; Mittal, Ruchi; Jain, Rajat; Sangwan, Virender S

    2014-01-01

    Descemet membrane endothelial keratoplasty (DMEK) was performed in a 70-year-old man diagnosed with pseudophakic bullous keratopathy. During Descemet endothelial complex (DEC) preparation, a central tear was noticed in the DMEK graft. However, the surgery was continued. On sixth postoperative day, a small fluid pocket was observed between the DEC and the posterior host stroma in inferior third of the graft area. It was, however, decided to observe it for spontaneous attachment. At 2 weeks, the inferior DEC detachment had increased with overlying corneal oedema. Descemetopexy with 100% air was performed the same day which reattached the DEC. Subsequently, DEC remained attached and at the last follow-up of 2 months, DEC was well opposed with a clear overlying cornea. The final best-corrected Snellen's visual acuity was 20/60. A small tear in the DEC does not necessitate tissue replacement and a good anatomical and visual outcome can be achieved in such cases. PMID:24973345

  4. Deployable Wireless Camera Penetrators

    NASA Technical Reports Server (NTRS)

    Badescu, Mircea; Jones, Jack; Sherrit, Stewart; Wu, Jiunn Jeng

    2008-01-01

    A lightweight, low-power camera dart has been designed and tested for context imaging of sampling sites and ground surveys from an aerobot or an orbiting spacecraft in a microgravity environment. The camera penetrators also can be used to image any line-of-sight surface, such as cliff walls, that is difficult to access. Tethered cameras to inspect the surfaces of planetary bodies use both power and signal transmission lines to operate. A tether adds the possibility of inadvertently anchoring the aerobot, and requires some form of station-keeping capability of the aerobot if extended examination time is required. The new camera penetrators are deployed without a tether, weigh less than 30 grams, and are disposable. They are designed to drop from any altitude with the boost in transmitting power currently demonstrated at approximately 100-m line-of-sight. The penetrators also can be deployed to monitor lander or rover operations from a distance, and can be used for surface surveys or for context information gathering from a touch-and-go sampling site. Thanks to wireless operation, the complexity of the sampling or survey mechanisms may be reduced. The penetrators may be battery powered for short-duration missions, or have solar panels for longer or intermittent duration missions. The imaging device is embedded in the penetrator, which is dropped or projected at the surface of a study site at 90 to the surface. Mirrors can be used in the design to image the ground or the horizon. Some of the camera features were tested using commercial "nanny" or "spy" camera components with the charge-coupled device (CCD) looking at a direction parallel to the ground. Figure 1 shows components of one camera that weighs less than 8 g and occupies a volume of 11 cm3. This camera could transmit a standard television signal, including sound, up to 100 m. Figure 2 shows the CAD models of a version of the penetrator. A low-volume array of such penetrator cameras could be deployed from an

  5. Image-guided modified deep anterior lamellar keratoplasty (DALK) corneal transplant using intraoperative optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Tao, Yuankai K.; LaBarbera, Michael; Ehlers, Justis P.; Srivastava, Sunil K.; Dupps, William J.

    2015-03-01

    Deep anterior lamellar keratoplasty (DALK) is an alternative to full-thickness corneal transplant and has advantages including the absence of allograft rejection; shortened duration of topical corticosteroid treatment and reduced associated risk of glaucoma, cataract, or infection; and enables use of grafts with poor endothelial quality. DALK begins by performing a trephination of approximately 80% stromal thickness, as measured by pachymetry. After removal of the anterior stoma, a needle is inserted into the residual stroma to inject air or viscoelastic to dissect Descemet's membrane. These procedures are inherently difficult and intraoperative rates of Descemet's membrane perforation between 4-39% have been reported. Optical coherence tomography (OCT) provides high-resolution images of tissue microstructures in the cornea, including Descemet's membrane, and allows quantitation of corneal layer thicknesses. Here, we use crosssectional intraoperative OCT (iOCT) measurements of corneal thickness during surgery and a novel micrometeradjustable biopsy punch to precision-cut the stroma down to Descemet's membrane. Our prototype cutting tool allows us to establish a dissection plane at the corneal endothelium interface, mitigates variability in cut-depths as a result of tremor, reduces procedure complexity, and reduces complication rates. iOCT-guided modified DALK procedures were performed on 47 cadaveric porcine eyes by non-experts and achieved a perforation rate of ~5% with a mean corneal dissection time <18 minutes. The procedure was also successful performed on a human donor eye without perforation. Our data shows the potential for iOCT-guided precision anterior segment surgery without variability as a result of tremor and improvements to standard clinical care.

  6. Deep Anterior Lamellar Keratoplasty Using the Big-Bubble Technique in Keratoconus

    PubMed Central

    Javadi, Mohammad-Ali; Feizi, Sepehr; Jamali, Hossein; Mirbabaee, Firooz

    2009-01-01

    Purpose To evaluate the visual outcomes and complications of deep anterior lamellar keratoplasty (DALK) using the big-bubble technique in patients with keratoconus. Methods In this case series, 104 eyes of 99 patients with moderate to advanced keratoconus underwent DALK. All subjects were contact lens intolerant or had unacceptable spectacle-corrected visual acuity. DALK was performed using the big-bubble technique. Full thickness donor corneas devoid of Descemet’s membrane (DM) were sutured to the recipient bed. Best spectacle-corrected visual acuity (BSCVA), refractive status, and intra- and postoperative complications were evaluated. Results Patients were male in 62.5%. Mean age of patients was 26.2±7.79 (range 15–46) years at the time of DALK and were followed for 23.07±8.1 (range 9–42) months. Mean BSCVA increased from 1.23±0.4 logMAR to 0.26±0.2 logMAR at final follow-up (P<0.001). Postoperative mean spherical equivalent refractive error and refractive and keratometric astigmatism were −3.41±3.1 D, 3.07±2.4 D, and 3.64±2.2 D, respectively. Bared DM was achieved in 86 (82.7%) eyes. Main complications encountered included filamentary keratitis (19.2%), non-endothelial graft rejection (14.4%), and suture abscess (10.6%). Conclusion DALK using the bigbubble technique appears to be a safe and effective procedure in patients with keratoconus. PMID:23056667

  7. A Novel Tectonic Keratoplasty with Femtosecond Laser Intrastromal Lenticule for Corneal Ulcer and Perforation

    PubMed Central

    Jiang, Yang; Li, Ying; Liu, Xiao-Wei; Xu, Jing

    2016-01-01

    Background: Small incision refractive lenticule extraction (SMILE) is an effective laser procedure that treats myopia. This research was to describe a novel approach to treat corneal ulcer or perforation using the corneal lenticules obtained from SMILE and to evaluate the safety and effectiveness of tectonic keratoplasty with femtosecond laser intrastromal lenticule (TEKIL). Methods: A total of twenty patients (22 eyes) were monitored for at least 6 months and were assessed using slit lamp microscopy, optical coherence tomography, and best-corrected visual acuity (BCVA). Postoperative complications throughout the study period were recorded. Results: Corneal ulcer in 14 patients (16 eyes) and corneal perforation in six patients (6 eyes) were treated with TEKIL. The patients were ten females and ten males, with a mean age of 58.5 ± 16.3 years (range: 16–81 years). In this study, the most causes of corneal ulcer or perforation were immunologic causes (54.5%). After TEKIL procedure, global integrity was achieved in all cases. No immune rejection or perforation was detected. The mean BCVA improved from 0.17 ± 0.20 preoperatively to 0.27 ± 0.25 postoperatively at the final follow-up (t = 2.095, P = 0.052). The postoperative BCVA improved in 12 eyes (54.5%) and maintained in nine eyes (40.9%). Vision function successfully maintained in all eyes (100%). In three cases, corneal ulcers were treated by reoperation of TEKIL at 3 months after the initial surgery for the reason that the residual corneal thickness was <250 μm. Conclusions: TEKIL seems to be an effective treatment for corneal ulcer and perforation in the condition of emergency and donor shortage. PMID:27453231

  8. Risk Factors for Eye Bank Preparation Failure of Descemet Membrane Endothelial Keratoplasty Tissue

    PubMed Central

    VIANNA, LUCAS M.M.; STOEGER, CHRISTOPHER G.; GALLOWAY, JOSHUA D.; TERRY, MARK; COPE, LESLIE; BELFORT, RUBENS; JUN, ALBERT S.

    2016-01-01

    PURPOSE To assess the results of a single eye bank preparing a high volume of Descemet membrane endothelial keratoplasty (DMEK) tissues using multiple technicians to provide an overview of the experience and to identify possible risk factors for DMEK preparation failure. DESIGN Cross-sectional study. METHODS SETTING Lions VisionGift and Wilmer Eye Institute at Johns Hopkins Hospital. STUDY POPULATION All 563 corneal tissues processed by technicians at Lions VisionGift for DMEK between October 2011 and May 2014 inclusive. OBSERVATION PROCEDURES Tissues were divided into 2 groups: DMEK preparation success and DMEK preparation failure. MAIN OUTCOME MEASURES We compared donor characteristics, including past medical history. RESULTS The overall tissue preparation failure rate was 5.2%. Univariate analysis showed diabetes mellitus (P = .000028) and its duration (P = .023), hypertension (P = .021), and hyperlipidemia or obesity (P = .0004) were more common in the failure group. Multivariate analysis showed diabetes mellitus (P = .0001) and hyperlipidemia or obesity (P = .0142) were more common in the failure group. Elimination of tissues from donors either with diabetes or with hyperlipidemia or obesity reduced the failure rate from 5.2% to 2.2%. Trends toward lower failure rates occurring with increased technician experience also were found. CONCLUSIONS Our work showed that tissues from donors with diabetes mellitus (especially with longer disease duration) and hyperlipidemia or obesity were associated with higher failure rates in DMEK preparation. Elimination of tissues from donors either with diabetes mellitus or with hyperlipidemia or obesity reduced the failure rate. In addition, our data may provide useful initial guidelines and benchmark values for eye banks seeking to establish and maintain DMEK programs. PMID:25640409

  9. Complications and management in Descemet's stripping endothelial keratoplasty: Analysis of consecutive 430 cases

    PubMed Central

    Basak, Samar K; Basak, Soham

    2014-01-01

    Purpose: To analyze the complications and their managements in Descemet's stripping endothelial keratoplasty (DSEK) in consecutive 430 cases by single surgeon in a tertiary eye hospital. Materials and Methods: 430 eyes of 366 patients with endothelial dysfunctions scheduled for DSEK, were analyzed retrospectively. In all cases donor dissection was performed manually, and ‘Taco’ insertion and unfolding technique was used. Intra-operative and postoperative complications with their managements and outcomes were reviewed retrospectively. Periodic endothelial cell density was analyzed for each patient till the last visit. Follow-up period was between 3 to 60 months (mean 18.7 months). Results: 13 (3.0%) eyes had operative complications during donor dissection and 16 (3.7%) had during recipient procedure. In 7 (1.6%) eyes, donor lenticule was replaced with a new one during the surgery. In early postoperative period, 21 (4.9%) eyes had donor dislocation and 12 (2.8%) eyes had air-induced pupillary block; and they were managed immediately. 2 cases had primary graft failure and in 1 case had postoperative bacterial endophthalmitis requiring evisceration. In late postoperative period, 48 (11.3%) eyes had secondary glaucoma and 14 (3.3%) eyes had late secondary graft failure. Endothelial rejection occurred in 5 (1.2%) cases. Mean endothelial cell loss was 19.7% after 3 months and 54.2% after 5 years. Total graft failure in this series was 31 (7.2%) and in 17 cases re-DSEK was performed successfully. Conclusions: Both operative and postoperative complications do occur in DSEK. Most of these complications can be managed by medical or appropriate surgical means. Some of the complications can be avoided and reduced with experience. PMID:24008797

  10. Deep Anterior Lamellar Keratoplasty in Keratoconic Patients with versus without Vernal Keratoconjunctivitis

    PubMed Central

    Feizi, Sepehr; Javadi, Mohammad Ali; Javadi, Fatemeh; Jafarinasab, Mohammad Reza

    2015-01-01

    Purpose: To compare the clinical outcomes of deep anterior lamellar keratoplasty (DALK) for keratoconus in patients with vernal keratoconjunctivitis (VKC) versus those without VKC. Methods: In this retrospective comparative study, records of 262 eyes with keratoconus (Group 1) and 28 keratoconic eyes with VKC (Group 2) that had undergone DALK were compiled. Reviewed parameters included length of follow-up, best-corrected visual acuity (BCVA), refractive error, complications and cumulative graft survival. Results: Mean duration of follow-up was 38.6 ± 20.2 and 34.4 ± 20.9 months in groups 1 and 2, respectively (P = 0.21). Mean post-operative BCVA was 0.19 ± 0.11 and 0.20 ± 0.15 logMAR, in groups 1 and 2 (P = 0.79). BCVA≥20/40 was achieved in 91.6 and 88.5% of eyes in groups 1 and 2, respectively (P = 0.48). Epithelial problems were encountered in 31.3 and 42.9% of operated eyes, respectively (P = 0.16). Vascularization of suture tracts and stitch abscesses were encountered more frequently in the eyes with VKC (P = 0.01 and <0.001, respectively). At the 33-month follow-up examination, rejection-free graft survival rates were 56.0% in group 1 and 33.3% in group 2, with mean durations of 41.0 and 32.1 months, respectively (P = 0.15). Graft survival rates were 98.1% in group 1 and 95.0% in group 2, with mean durations of 88.6 and 88.4 months, respectively (P = 0.74). Conclusion: Clinical outcomes of DALK in keratoconic eyes with VKC were comparable to those in eyes with keratoconus alone. However, complications such as suture tract vascularization and stitch abscesses were more common when VKC coexisted, necessitating closer monitoring. PMID:26425311

  11. Two cases of ultrathin Descemet stripping automated endothelial keratoplasty utilizing a graft that had undergone radial keratotomy.

    PubMed

    Nahum, Yoav; Ponzin, Diego; Busin, Massimo

    2016-02-01

    This is a report of two cases in which tissue that had undergone radial keratotomy (RK) was utilized for double-pass ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK). Postoperative slit-lamp examination, visual acuity, anterior segment optical coherence tomography, and specular microscopy were available 30 months after surgery. Both corneas from a donor, who had undergone RK several years before his demise, and were otherwise suitable for endothelial keratoplasty were prepared for UT-DSAEK using double-pass dissection using first a 300 mm microkeratome head and then a 130μm microkeratome head (ALTK system, Moria, Antony, France). After the second cut, the tissue was punched to 9.0 mm and transplanted in two eyes with endothelial decompensation according to standard technique. As early as 3 months after surgery, both patients had 20/25 best-corrected visual acuity, which remained stable for the following 27 months. Postoperative endothelial cell loss was 34% and 57% at 2.5 years. In conclusion, post-RK donor tissue can be used for UT-DSAEK. PMID:27050357

  12. Two cases of ultrathin Descemet stripping automated endothelial keratoplasty utilizing a graft that had undergone radial keratotomy

    PubMed Central

    Nahum, Yoav; Ponzin, Diego; Busin, Massimo

    2016-01-01

    This is a report of two cases in which tissue that had undergone radial keratotomy (RK) was utilized for double-pass ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK). Postoperative slit-lamp examination, visual acuity, anterior segment optical coherence tomography, and specular microscopy were available 30 months after surgery. Both corneas from a donor, who had undergone RK several years before his demise, and were otherwise suitable for endothelial keratoplasty were prepared for UT-DSAEK using double-pass dissection using first a 300 mm microkeratome head and then a 130μm microkeratome head (ALTK system, Moria, Antony, France). After the second cut, the tissue was punched to 9.0 mm and transplanted in two eyes with endothelial decompensation according to standard technique. As early as 3 months after surgery, both patients had 20/25 best-corrected visual acuity, which remained stable for the following 27 months. Postoperative endothelial cell loss was 34% and 57% at 2.5 years. In conclusion, post-RK donor tissue can be used for UT-DSAEK. PMID:27050357

  13. Elevated Intraocular Pressure after Descemet Stripping Automated Endothelial Keratoplasty in Patients with a Trabeculectomy: A Case Series

    PubMed Central

    Chan, Elsie; Ang, Ghee Soon; George Kong, Yu Xiang

    2015-01-01

    ABSTRACT We report a case series of three patients with previous trabeculectomies who developed elevated intraocular pressure (IOP) in the immediate postoperative period after routine Descemet stripping automated endothelial keratoplasty (DSAEK). All patients had functioning trabeculectomies preoperatively, and developed elevated IOP between 41 and 69 mm Hg within 24 hours following DSAEK surgery. The IOP was successfully controlled in all patients with topical IOP-lowering medications and oral acetazolamide, with the addition of ocular massage and release of aqueous for two patients. Thereafter, all patients maintained well-controlled IOPs. Patients with trabeculectomies should be followed-up closely immediately after DSAEK to monitor for raised IOP. The mechanism for this pressure rise is uncertain, but may involve air in the trabeculectomy sclerostomy or bleb resulting in blockage of aqueous flow. How to cite this article: Sheales MPH, Chan E, Ang GS, Kong YXG. Elevated Intraocular Pressure after Descemet Stripping Automated Endothelial Keratoplasty in Patients with a Trabeculectomy: A Case Series. J Curr Glaucoma Pract 2015;9(3):100-103. PMID:26997845

  14. Descemet Stripping Automated Endothelial Keratoplasty for Endothelial Dysfunction in Xeroderma Pigmentosum: A Clinicopathological Correlation and Review of Literature.

    PubMed

    Vira, Divya; Fernandes, Merle; Mittal, Ruchi

    2016-07-01

    Xeroderma pigmentosum (XP) mainly affects the ocular surface; however, endothelial damage may also occur. We would like to report changes in the endothelial-Descemet layer and review the literature on similar findings in patients with XP, including the role of Descemet stripping automated endothelial keratoplasty (DSAEK) in the management of a 21-year-old man who presented with nonresolving corneal edema in the right eye after excision biopsy for conjunctival intraepithelial neoplasia. His best-corrected visual acuity (BCVA) was 20/200 in the right eye and 20/20 in the left eye. On general examination, there was patchy hyperpigmentation of the exposed areas of skin suggestive of XP. On examination of the right eye, there was stromal edema involving the exposed half of cornea. The left eye appeared normal. Pachymetry readings were 860 and 600 μm in the right and left eye, respectively. Descemet stripping automated endothelial keratoplasty was performed for endothelial dysfunction and the stripped endothelium, and Descemet membrane (DM) was sent for histopathologic evaluation. Postoperatively, the donor lenticule was well apposed and the overlying stromal edema resolved. The patient achieved a BCVA of 20/30 in the right eye without progression of corneal scarring at 1-year follow-up. In the meanwhile, however, the left eye developed corneal edema. Histopathology revealed gross attenuation of endothelial cells with uniform thickness of the DM. Corneal endothelial dysfunction in XP is amenable to treatment with DSAEK. PMID:25996422

  15. Soil penetrometers and penetrability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil penetrometers are useful tools that measure the penetrability, or strength, of a soil. They can be as simple as a rod or shaft with a blunt or sharp end, or complicated mechanically driven instruments with digital data collection systems. Regardless of their design, soil penetrometers measure s...

  16. Penetration resistant barrier

    DOEpatents

    Hoover, William R.; Mead, Keith E.; Street, Henry K.

    1977-01-01

    The disclosure relates to a barrier for resisting penetration by such as hand tools and oxy-acetylene cutting torches. The barrier comprises a layer of firebrick, which is preferably epoxy impregnated sandwiched between inner and outer layers of steel. Between the firebrick and steel are layers of resilient rubber-like filler.

  17. Jet penetration in glass

    SciTech Connect

    Moran, B.; Glenn, L.A.; Kusubov, A.

    1991-05-01

    We describe a phenomenological model which accounts for the mechanical response of glass to intense impulsive loading. An important aspect of this response is the dilatancy accompanying fracture. We have also conducted a number of experiments with 38.1-mm diameter precision shaped charges to establish the performance against various targets and to allow evaluation of our model. At 3 charge diameters standoff, the data indicate that both virgin and damaged glass offer better (Bernoulli-scaled) resistance to penetration than either of 4340 steel, or 6061-T6 aluminum alloy. Time-resolved measurements indicate two distinct phases of jet penetration in glass: An initial hydrodynamic phase, and a second phase characterized by a slower penetration velocity. Our calculations show that at early time, a crater is formed around the jet and only the tip of the undisturbed jet interacts with the glass. At late time the glass has collapsed on the jet and degraded penetration continues via a disturbed and fragmented jet.

  18. Single wall penetration equations

    NASA Technical Reports Server (NTRS)

    Hayashida, K. B.; Robinson, J. H.

    1991-01-01

    Five single plate penetration equations are compared for accuracy and effectiveness. These five equations are two well-known equations (Fish-Summers and Schmidt-Holsapple), two equations developed by the Apollo project (Rockwell and Johnson Space Center (JSC), and one recently revised from JSC (Cour-Palais). They were derived from test results, with velocities ranging up to 8 km/s. Microsoft Excel software was used to construct a spreadsheet to calculate the diameters and masses of projectiles for various velocities, varying the material properties of both projectile and target for the five single plate penetration equations. The results were plotted on diameter versus velocity graphs for ballistic and spallation limits using Cricket Graph software, for velocities ranging from 2 to 15 km/s defined for the orbital debris. First, these equations were compared to each other, then each equation was compared with various aluminum projectile densities. Finally, these equations were compared with test results performed at JSC for the Marshall Space Flight Center. These equations predict a wide variety of projectile diameters at a given velocity. Thus, it is very difficult to choose the 'right' prediction equation. The thickness of a single plate could have a large variation by choosing a different penetration equation. Even though all five equations are empirically developed with various materials, especially for aluminum alloys, one cannot be confident in the shield design with the predictions obtained by the penetration equations without verifying by tests.

  19. Tumor-Penetrating Peptides

    PubMed Central

    Teesalu, Tambet; Sugahara, Kazuki N.; Ruoslahti, Erkki

    2013-01-01

    Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC), contains the integrin-binding RGD motif. RGD mediates tumor-homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR) motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular “zip code” of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies, and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is present in the

  20. Biomechanics of penetrating trauma.

    PubMed

    Yoganandan, N; Pintar, F A

    1997-01-01

    It is well known that injuries and deaths due to penetrating projectiles have become a national and an international epidemic in Western society. The application of biomedical engineering to solve day-to-day problems has produced considerable advances in safety and mitigation/prevention of trauma. The study of penetrating trauma has been largely in the military domain where war-time specific applications were advanced with the use of high-velocity weapons. With the velocity and weapon caliber in the civilian population at half or less compared with the military counterpart, wound ballistics is a largely different problem in today's trauma centers. The principal goal of the study of penetrating injuries in the civilian population is secondary prevention and optimized emergency care after occurrence. A thorough understanding of the dynamic biomechanics of penetrating injuries quantifies missile type, caliber, and velocity to hard and soft tissue damage. Such information leads to a comprehensive assessment of the acute and long-term treatment of patients with penetrating injuries. A review of the relevant military research applied to the civilian domain and presentation of new technology in the biomechanical study of these injuries offer foundation to this field. Relevant issues addressed in this review article include introduction of the military literature, the need for secondary prevention, environmental factors including projectile velocity and design, experimental studies with biological tissues and physical models, and mathematical simulations and analyses. Areas of advancement are identified that enables the pursuit of biomechanics research in order to arrive at better secondary prevention strategies. PMID:9719858

  1. Cost Minimization Analysis of Precut Cornea Grafts in Descemet Stripping Automated Endothelial Keratoplasty

    PubMed Central

    Yong, Kai-Ling; Nguyen, Hai V.; Cajucom-Uy, Howard Y.; Foo, Valencia; Tan, Donald; Finkelstein, Eric A.; Mehta, Jodhbir S.

    2016-01-01

    Abstract Descemet stripping automated endothelial keratoplasty (DSAEK) is the most common corneal transplant procedure. A key step in the procedure is preparing the donor cornea for transplantation. This can be accomplished via 1 of 3 alternatives: surgeon cuts the cornea on the day of surgery, the cornea is precut ahead of time in an offsite facility by a trained technician, or a precut cornea is purchased from an eye bank. Currently, there is little evidence on the costs and effectiveness of these 3 strategies to allow healthcare providers decide upon the preferred method to prepare grafts. The aim of this study was to compare the costs and relative effectiveness of each strategy. The Singapore National Eye Centre and Singapore Eye Bank performed both precut cornea and surgeon-cut cornea transplant services between 2009 and 2013. This study included 110 subjects who received precut cornea and 140 who received surgeon-cut cornea. Clinical outcomes and surgical duration were compared across the strategies using the propensity score matching. The cost of each strategy was estimated using the microcosting and consisted of facility costs and procedural costs including surgical duration. One-way sensitivity analysis and threshold analysis were performed. The cost for DSAEK was highest for the surgeon-cut approach ($13,965 per procedure), followed by purchasing precut corneas ($12,659) and then setting up precutting ($12,421). The higher procedural cost of the surgeon-cut approach was largely due to the longer duration of the procedure (surgeon-cut = 72.54 minutes, precut = 59.45 minutes, P < 0.001) and the higher surgeon fees. There was no evidence of differences in clinical outcomes between grafts that were precut or surgeon-cut. Threshold analysis demonstrated that if the number of cases was below 31 a year, the strategy that yielded the lowest cost was purchasing precut cornea from eye bank. If there were more than 290 cases annually, the cheapest

  2. Cost Minimization Analysis of Precut Cornea Grafts in Descemet Stripping Automated Endothelial Keratoplasty.

    PubMed

    Yong, Kai-Ling; Nguyen, Hai V; Cajucom-Uy, Howard Y; Foo, Valencia; Tan, Donald; Finkelstein, Eric A; Mehta, Jodhbir S

    2016-02-01

    Descemet stripping automated endothelial keratoplasty (DSAEK) is the most common corneal transplant procedure. A key step in the procedure is preparing the donor cornea for transplantation. This can be accomplished via 1 of 3 alternatives: surgeon cuts the cornea on the day of surgery, the cornea is precut ahead of time in an offsite facility by a trained technician, or a precut cornea is purchased from an eye bank. Currently, there is little evidence on the costs and effectiveness of these 3 strategies to allow healthcare providers decide upon the preferred method to prepare grafts.The aim of this study was to compare the costs and relative effectiveness of each strategy.The Singapore National Eye Centre and Singapore Eye Bank performed both precut cornea and surgeon-cut cornea transplant services between 2009 and 2013.This study included 110 subjects who received precut cornea and 140 who received surgeon-cut cornea. Clinical outcomes and surgical duration were compared across the strategies using the propensity score matching. The cost of each strategy was estimated using the microcosting and consisted of facility costs and procedural costs including surgical duration. One-way sensitivity analysis and threshold analysis were performed.The cost for DSAEK was highest for the surgeon-cut approach ($13,965 per procedure), followed by purchasing precut corneas ($12,659) and then setting up precutting ($12,421). The higher procedural cost of the surgeon-cut approach was largely due to the longer duration of the procedure (surgeon-cut = 72.54 minutes, precut = 59.45 minutes, P < 0.001) and the higher surgeon fees. There was no evidence of differences in clinical outcomes between grafts that were precut or surgeon-cut. Threshold analysis demonstrated that if the number of cases was below 31 a year, the strategy that yielded the lowest cost was purchasing precut cornea from eye bank. If there were more than 290 cases annually, the cheapest option would be

  3. Pitfalls in penetrating trauma.

    PubMed

    van Vugt, A B

    2003-08-01

    In Western Europe the most frequent cause of multiple injuries is blunt trauma. Only few of us have experience with penetrating trauma, without exception far less than in the USA or South-Africa. In Rotterdam, the Erasmus Medical Centre is a level I trauma centre, situated directly in the town centre. All penetrating traumas are directly presented to our emergency department by a well organized ambulance service supported by a mobile medical team if necessary. The delay with scoop and run principles is very short for these cases, resulting in severely injured reaching the hospital alive in increasing frequency. Although the basic principles of trauma care according to the guidelines of the Advanced Trauma Life Support (ATLS) (1-2) are the same for blunt and penetrating trauma with regard to priorities, diagnostics and primary therapy, there are some pitfalls in the strategy of management in penetrating trauma one should be aware of. Simple algorithms can be helpful, especially in case of limited experience (3). In case of life-saving procedures, the principles of Damage Control Surgery (DCS) must be followed (4-5). This approach is somewhat different from "traditional" surgical treatment. In the Ist phase prompt interventions by emergency thoracotomy and laparotomy are carried out, with only two goals to achieve: surgical control of haemorrhage and contamination. After temporary life-saving procedures, the 2nd phase is characterized by intensive care treatment, dealing with hypothermia, metabolic acidosis and clotting disturbances. Finally in the 3rd phase, within 6-24 hours, definitive surgical care takes place. In this overview, penetrating injuries of neck, thorax, abdomen and extremities will be outlined. Penetrating cranial injuries, as a neurosurgical emergency with poor prognosis, are not discussed. History and physical examination remain the corner stones of good medical praxis. In a work-up according to ATLS principles airway, breathing and circulation

  4. Ground-penetrating rada

    NASA Astrophysics Data System (ADS)

    Thuma, W. R.

    The theory and applications of digital Ground-Penetrating Radar were discussed at a 5-day seminar held at the China University of Geosciences in Wuhan, People's Republic of China, in April. Cohosted by the Department of Applied Geophysics and Canada-China Geoscience, more than 60 senior geophysicists, engineers, technical specialists, university professors and researchers attended.Focus of the meeting was the expanded uses of the new deep-penetrating fully digital PulseEKKO, which is gaining wide acceptance around the world. Attendees showed intense interest in this new and unique technology. Applications covered were groundwater and mineral exploration; engineering, construction and toxic waste site surveying; tunnel and underground mine probing for potential geological hazards, blind ore zones, karst cavities and solution pathways; and locating buried objects such as petroleum storage tanks, unexploded bombs and archeological remains.

  5. Penetrable wedge analysis

    NASA Astrophysics Data System (ADS)

    Scharstein, Robert W.; Davis, Anthony M.

    1994-07-01

    Two complementary analyses of the time-harmonic scattering by a penetrable wedge are presented. The distance from the apex (appropriately scaled by the wavenumber in the exterior region) of the exciting line source is the single length scale in this infinite-domain boundary value problem. The work summarized herein represents two mathematical approaches (among a series of candidates) to solve this important scattering problem and to visualize the wave physics.

  6. Penetrating extremity trauma.

    PubMed

    Ivatury, Rao R; Anand, Rahul; Ordonez, Carlos

    2015-06-01

    Penetrating extremity trauma (PET) usually becomes less important when present along with multiple truncal injuries. The middle eastern wars documented the terrible mortality and morbidity resulting from PET. Even in civilian trauma, PET can lead to significant morbidity and mortality. There are now well-established principles in the evaluation and management of vascular, bony, soft tissue, and neurologic lesions that will lead to a reduction of the poor outcomes. This review will summarize some of these recent concepts. PMID:25413177

  7. Prediction of alumina penetration

    SciTech Connect

    Mandell, D A

    1993-02-01

    The MESA hydrocode was used to predict two-dimensional tests of L/D 10 and L/D 15 tungsten rods impacting AD 90 alumina with a steel backing. The residual penetration into the steel is the measured quantity in these experiments conducted at the Southwest Research Institute (SWR). The interface velocity as a function of time between an alumina target and a lithium fluoride window, impacted by an alumina disk at velocities between 544 m/s and 2329 m/s, was also predicted. These one-dimensional flyer plate experiments were conducted at Sandia National Laboratories using Coors AD 995 alumina. The material strength and fracture models are important in the prediction of ceramic experiments. The models used in these predictions are discussed. The penetrations in the two-dimensional tests were predicted to 11.4 percent or better. In five of the six experiments, the predicted penetration depth was deeper than the measured value. This trend is expected since the calculation is based on ideal conditions. The results show that good agreement between the 1-D flyer plate data and the MESA predictions exists at the lower impact velocities, but the maximum velocity is overpredicted as the flyer plate velocity increases. At a flyer plate velocity of 2329 m/s the code overpredicted the data by 12.3 percent.

  8. Penetrating cardiac injuries.

    PubMed

    Mittal, V; McAleese, P; Young, S; Cohen, M

    1999-05-01

    Our objective was to determine the influence of several clinical factors on the survival of patients with penetrating wounds to the heart. A retrospective review of 80 consecutive penetrating cardiac injuries treated in a Level II urban trauma center from 1980 through 1994 were examined. Thirty-six patients (45%) had gunshot wounds (including 1 shotgun wound), and 44 (55%) had stab wounds. Intervention consisted of emergency room (ER) or operating room thoracotomy. We measured the effect of several clinical factors on morbidity and patient survival. Survival rate was 17 of 36 (47%) in gunshot injuries and 35 of 44 (80%) in stab injuries, with an overall survival rate of 52 of 80 patients (65%). The average age was 24 years (range, 9-53), and there were 3 female patients. Twelve patients (15%) had multiple cardiac injuries, and 63 (79%) had other associated injuries. Fourteen patients (17%) presented with no blood pressure, and 55 (69%) were hypotensive on admission. ER thoracotomy was performed on 7 of 52 survivors (13%) and 24 of 28 nonsurvivors (86%). Survival after ER thoracotomy was 7 of 31 patients (22%). A selective approach is recommended, because ER thoracotomy has a limited role in penetrating cardiac injury. A high index of suspicion, prompt resuscitation, and immediate definitive surgical management resulted in a high survival rate for these frequently lethal injuries. PMID:10231214

  9. Mars penetrator: Subsurface science mission

    NASA Technical Reports Server (NTRS)

    Lumpkin, C. K.

    1974-01-01

    A penetrator system to emplace subsurface science on the planet Mars is described. The need for subsurface science is discussed, and the technologies for achieving successful atmospheric entry, Mars penetration, and data retrieval are presented.

  10. Simplified analytical model of penetration with lateral loading -- User`s guide

    SciTech Connect

    Young, C.W.

    1998-05-01

    The SAMPLL (Simplified Analytical Model of Penetration with Lateral Loading) computer code was originally developed in 1984 to realistically yet economically predict penetrator/target interactions. Since the code`s inception, its use has spread throughout the conventional and nuclear penetrating weapons community. During the penetrator/target interaction, the resistance of the material being penetrated imparts both lateral and axial loads on the penetrator. These loads cause changes to the penetrator`s motion (kinematics). SAMPLL uses empirically based algorithms, formulated from an extensive experimental data base, to replicate the loads the penetrator experiences during penetration. The lateral loads resulting from angle of attack and trajectory angle of the penetrator are explicitly treated in SAMPLL. The loads are summed and the kinematics calculated at each time step. SAMPLL has been continually improved, and the current version, Version 6.0, can handle cratering and spall effects, multiple target layers, penetrator damage/failure, and complex penetrator shapes. Version 6 uses the latest empirical penetration equations, and also automatically adjusts the penetrability index for certain target layers to account for layer thickness and confinement. This report describes the SAMPLL code, including assumptions and limitations, and includes a user`s guide.

  11. Visco-elastic and thermal-induced damaging in time-dependent reshaping of human cornea after conductive keratoplasty

    NASA Astrophysics Data System (ADS)

    Fraldi, M.; Cutolo, A.; Esposito, L.; D'Amore, A.

    2016-06-01

    With the aim of investigating the role played by both the radiofrequency-induced thermal damaging and the viscoelasticity of the tissue in human cornea surface reshaping—time dependent key factors for the success of the surgical outcome in the short-term post-intervention period—the Conductive Keratoplasty (CK, a surgical technique used for the correction of farsightedness) has been simulated with reference to the protocol adopted for moderate hyperopia. By means of a transient thermal analysis, the amount of the local thermal-induced tissue damaging has been computed in order to remap the constitutive properties of the corneal tissue. Successively, a mechanical non-linear analysis has been performed for predicting the corneal curvature around the optical zone during the post-surgery period. The study aims to contribute some firm thermo-mechanical roots to better understand the corneal tissue response to thermal insults and its reshaping predictability in a long period.

  12. Interface quality of different corneal lamellar–cut depths for femtosecond laser–assisted lamellar anterior keratoplasty

    PubMed Central

    Zhang, Chenxing; Bald, Matthew; Tang, Maolong; Li, Yan; Huang, David

    2015-01-01

    PURPOSE To evaluate interface quality of different corneal lamellar–cut depths with the femtosecond laser and determine a feasible range of depth for femtosecond laser–assisted lamellar anterior keratoplasty. SETTING Casey Eye Institute, Portland, Oregon, USA. DESIGN Experimental study. METHODS Full lamellar cuts were made on 20 deepithelialized human cadaver corneas using the femtosecond laser. The cut depth was 17% to 21% (100 μm), 31%, 35%, 38% to 40%, and 45% to 48% of the central stromal thickness. Scanning electron microscopy images of cap and bed surfaces were subjectively graded for ridge and roughness using a scale of 1 to 5 (1 = best). The graft–host match was evaluated by photography and optical coherence tomography in a simulated procedure. RESULTS The ridge score was correlated with the cut depth (P = .0078, R = 0.58) and better correlated with the percentage cut depth (P = .00024, R = 0.73). The shallowest cuts had the least ridges (score 1.25). The 31% cut depth produced significantly less ridges (score 2.15) than deeper cuts. The roughness score ranged from 2.19 to 3.08 for various depths. A simulated procedure using a 100 μm host cut and a 177 μm (31%) graft had a smooth interface and flush anterior junction using an inverted side-cut design. CONCLUSIONS The femtosecond laser produced more ridges in deeper lamellar cuts. A depth setting of 31% stromal thickness might produce adequate surface quality for femtosecond laser–assisted lamellar anterior keratoplasty. The inverted side-cut design produced good edge apposition even when the graft was thicker than the host lamellar–cut depth. PMID:25747165

  13. Endothelial cell loss and complication rates with combined Descemets stripping endothelial keratoplasty and cataract surgery in a UK centre

    PubMed Central

    Jones, S M; Fajgenbaum, M A; Hollick, E J

    2015-01-01

    Purpose To report 6-month, 1- and 2-year endothelial cell loss (ECL), intra- and postoperative complications in a large series of patients undergoing either Descemets stripping endothelial keratoplasty (DSEK) or a combined phacoemulsification and DSEK in a UK centre. Patients and methods Patients undergoing DSEK with or without concurrent cataract surgery were included in this retrospective study. Surgeries were performed between January 2006 and May 2013. Main outcomes included intra- and postoperative complications and percentage ECL. Results DSEK was performed in 226 eyes (210 patients). Of these, 141 eyes (126 patients) underwent DSEK alone and 85 eyes (84 patients) underwent DSEK combined with cataract surgery. Excluding complex anterior segment pathology the mean percentage ECL at 6, 12 and 24 months was 40.5±13.4, 45.1±14.6 and 53.1±13.0 in the DSEK group and 40.7±15.4, 42.6±15.3 and 49.6±16.5 in patients undergoing the combined procedure, respectively. There was no significant difference in percentage ECL at 6 or 24 months between the two groups both in complex and routine cases. Intraoperative complications occurred in four patients undergoing DSEK and three undergoing combined procedure. Postoperative complication rates did not reach statistical significance between the groups. Conclusion Mean ECL and complication rates were comparable at 6, 12 and 24 months in routine cases undergoing concurrent DSEK with cataract surgery and those undergoing DSEK. These data support the combined procedure in patients requiring both cataract surgery and endothelial keratoplasty. Further collaboration to report endothelial cell counts from other UK centres should be encouraged. PMID:25771818

  14. Simultaneous topography-guided PRK followed by corneal collagen cross-linking after lamellar keratoplasty for keratoconus

    PubMed Central

    Spadea, Leopoldo; Paroli, Marino

    2012-01-01

    Background The purpose of this paper is to report the results of using combined treatment of customized excimer laser-assisted photorefractive keratectomy (PRK) and prophylactic corneal collagen crosslinking (CXL) for residual refractive error in a group of patients who had previously undergone lamellar keratoplasty for keratoconus. Methods The study included 14 eyes from 14 patients who had originally been treated for keratoconus in one eye by excimer laser-assisted lamellar keratoplasty (ELLK), and subsequently presented with residual ametropia (−6.11 D ± 2.48, range −2.50 to −9.50). After a mean 40.1 ± 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided transepithelial excimer laser PRK (central corneal regularization) and corneal CXL induced by riboflavin-ultraviolet A. Results After a mean 15 ± 6.5 (range 6–24) months, all eyes gained at least one Snellen line of uncorrected distance visual acuity (range 1–10). No patient lost lines of corrected distance visual acuity, and four patients gained three lines of corrected distance visual acuity. Mean manifest refractive spherical equivalent was −0.79 ± 2.09 (range +1 to −3.0) D, and topographic keratometric astigmatism was 5.02 ± 2.93 (range 0.8–8.9) D. All the corneas remained clear (haze < 1). Conclusion The combination of customized PRK and corneal CXL provided safe and effective results in the management of corneal regularization for refractive purposes after ELLK for keratoconus. PMID:23152658

  15. Penetrating Fire Extinguisher

    NASA Technical Reports Server (NTRS)

    1985-01-01

    When Feecon Corporation, a manufacturer of fire protection systems, needed a piercing nozzle for larger aircraft, they were assisted by Kennedy Space Center who provided the company with a fire extinguisher with a hard pointed tip that had been developed in case of an orbiter crash landing. The nozzle can penetrate metal skins of aircraft, trains, etc. Feecon obtained a license and now markets its cobra ram piercing nozzle to airport firefighters. Its primary advantage is that the nozzle can be held in one spot during repeated blows of the ram. *This product has been discontinued and is no longer commercially available.

  16. Monolithic ballasted penetrator

    DOEpatents

    Hickerson, Jr., James P.; Zanner, Frank J.; Baldwin, Michael D.; Maguire, Michael C.

    2001-01-01

    The present invention is a monolithic ballasted penetrator capable of delivering a working payload to a hardened target, such as reinforced concrete. The invention includes a ballast made from a dense heavy material insert and a monolithic case extending along an axis and consisting of a high-strength steel alloy. The case includes a nose end containing a hollow portion in which the ballast is nearly completely surrounded so that no movement of the ballast relative to the case is possible during impact with a hard target. The case is cast around the ballast, joining the two parts together. The ballast may contain concentric grooves or protrusions that improve joint strength between the case and ballast. The case further includes a second hollow portion; between the ballast and base, which has a payload fastened within this portion. The penetrator can be used to carry instrumentation to measure the geologic character of the earth, or properties of arctic ice, as they pass through it.

  17. Skin penetration enhancers.

    PubMed

    Lane, Majella E

    2013-04-15

    The skin has evolved to prevent excessive water loss from the internal organs and to limit the ability of xenobiotics and hazardous substances to enter the body. Notwithstanding this barrier function, a number of strategies have been developed by scientists to deliver drugs to and through the skin. The aim of this review is to consider the various types of chemical penetration enhancers (CPEs) which have been investigated in the scientific literature. Potential pathways for CPEs to exert their action are examined with reference to the physical chemistry of passive skin transport. The emphasis is on those studies which have focussed on human and porcine skin because of the limitations associated with skin permeation data collated from other species. Where known, the mechanisms of action of these compounds are also discussed. Examples of enhancers used in commercial topical and transdermal formulations are provided. It is proposed that overall the effects of CPEs on the skin barrier may best be explained by a Diffusion-Partition-Solubility theory. Finally, some of the limitations of studies in the literature are considered and the importance of monitoring the fate of the penetration enhancer as well as the active is highlighted. PMID:23462366

  18. Penetration in GTA welding

    SciTech Connect

    Heiple, C.R.; Burgardt, P.

    1990-01-01

    The size and shape of the weld bead produced in GTA welding depends on the magnitude and distribution of the energy incident on the workpiece surfaces as well as the dissipation of that energy in the workpiece. The input energy is largely controllable through the welding parameters selected, however the dissipation of that energy in the workpiece is less subject to control. Changes in energy dissipation can produce large changes in weld shape or penetration. Heat transport away from the weld pool is almost entirely by conduction, but heat transport in the weld pool is more complicated. Heat conduction through the liquid is an important component, but heat transport by convection (mass transport) is often the dominant mechanism. Convective heat transport is directional and changes the weld pool shape from that produced by conduction alone. Surface tension gradients are often the dominant forces driving fluid flow in GTA weld pools. These gradients are sensitive functions of weld pool chemistry and the energy input distribution to the weld. Experimental and theoretical work conducted primarily in the past decade has greatly enhanced our understanding of weld pool fluid flow, the forces which drive it, and its effects on weld pool shape. This work is reviewed here. While less common, changes in energy dissipation through the unmelted portion of the workpiece can also affect fusion zone shape or penetration. These effects are also described. 41 refs., 9 figs.

  19. Pressure Measurement during Penetration Experiments

    NASA Astrophysics Data System (ADS)

    Krause, C.; Demming, J.; Flecht, T.; Heller, S.

    2014-04-01

    Penetration experiments are common tools for the investigation of physical surface properties. Additionally penetration experiments will find several applications in exploration missions in the near future. A penetration test stand has been flown for the investigation of penetration force reduction under reduced gravity in the 2nd Joint European Partial-G Parabolic Flight Campaign (JEPPF-2) of ESA, CNES and DLR [1]. The main contribution to the bearing resistance of a soil is combined of shaft and base resistance. During the penetration the grains of the granular material will be squeezed into the surrounding material. The penetration will cause a change in the pressure distribution inside the surrounding soil [2],[3]. An experimental setup has been designed and built for understanding and measurement of this induced pressure distribution. In the last year the parabolic flight test stand has been further developed for the measurement of pressure during the penetration process. The main part of the experiments stayed the same with a steel rod penetration into a sample cell measuring the penetration force and recording it in relation to the depth. The sample cell is equipped with a supporting sieving mechanism for sample preparation. The pressure sensors are mounted at the sample cell. During the last test campaigns the principle of measurement has been investigated and first measurements have been performed. In the presentation the measurement principle will be shown and its implementation into the parabolic flight setup. Pressure measurement results on ground tests of different penetrator and tip configurations will be presented.

  20. Penetrating abdominal trauma.

    PubMed

    Henneman, P L

    1989-08-01

    The management of patients with penetrating abdominal trauma is outlined in Figure 1. Patients with hemodynamic instability, evisceration, significant gastrointestinal bleeding, peritoneal signs, gunshot wounds with peritoneal violation, and type 2 and 3 shotgun wounds should undergo emergency laparotomy. The initial ED management of these patients includes airway management, monitoring of cardiac rhythm and vital signs, history, physical examination, and placement of intravenous lines. Blood should be obtained for initial hematocrit, type and cross-matching, electrolytes, and an alcohol level or drug screen as needed. Initial resuscitation should utilize crystalloid fluid replacement. If more than 2 liters of crystalloid are needed to stabilize an adult (less in a child), blood should be given. Group O Rh-negative packed red blood cells should be immediately available for a patient in impending arrest or massive hemorrhage. Type-specific blood should be available within 15 minutes. A patient with penetrating thoracic and high abdominal trauma should receive a portable chest x-ray, and a hemo- or pneumothorax should be treated with tube thoracostomy. An unstable patient with clinical signs consistent with a pneumothorax, however, should receive a tube thoracostomy prior to obtaining roentgenographic confirmation. If time permits, a nasogastric tube and Foley catheter should be placed, and the urine evaluated for blood (these procedures can be performed in the operating room). If kidney involvement is suspected because of hematuria or penetrating trauma in the area of a kidney or ureter in a patient requiring surgery, a single-shot IVP should be performed either in the ED or the operating room. An ECG is important in patients with possible cardiac involvement and in patients over the age of 40 going to the operating room. Tetanus status should be updated, and appropriate antibiotics covering bowel flora should be given. Operative management should rarely be delayed

  1. Water penetration study

    NASA Technical Reports Server (NTRS)

    Lockwood, H. E.

    1973-01-01

    Nine film-filter combinations have been tested for effectiveness in recording water subsurface detail when exposed from an aerial platform over a typical water body. An experimental 2-layer positive color film, a 2-layer (minus blue layer) film, a normal 3-layer color film, a panchromatic black-and-white film, and an infrared film with selected filters were tested. Results have been tabulated to show the relative capability of each film-filter combination for: (1) image contrast in shallow water (0 to 5 feet); (2) image contrast at medium depth (5 to 10 feet); (3) image contrast in deep water (10 feet plus); (4) water penetration; maximum depth where detail was discriminated; (5) image color (the spectral range of the image); (6) vegetation visible above a water background; (7) specular reflections visible from the water surface; and (8) visual compatibility; ease of discriminating image detail. Recommendations for future recording over water bodies are included.

  2. Hydraulic well penetration apparatus

    SciTech Connect

    Schellstede, H.J.; McQueen, R.W.; Peters, A.D.

    1990-05-29

    This patent describes a well penetrator. It comprises: housing means capable of being lowered down the interior of a well casing, a work fluid input means in the housing means,a movable punch member having an inner end and an outer end and being movable between a retracted position and an extended position. The outer end of the movable punch member including casing cutting means for cutting an opening in a casing when moved forcefully outwardly toward the extended position, punch support means supporting the punch member for movement relative to the housing means between the retracted position in which the outer end of the punch member is positioned substantially within the confines of the housing means and the extended position in which the outer end of the punch member is positioned outwardly of the housing means.

  3. Applications of Cell-Penetrating Peptides for Tumor Targeting and Future Cancer Therapies

    PubMed Central

    Regberg, Jakob; Srimanee, Artita; Langel, Ülo

    2012-01-01

    Cell-penetrating peptides provide a highly promising strategy for intracellular drug delivery. One relevant clinical application of cell-penetrating peptides is cancer therapeutics. Peptide based delivery could increase the uptake of drugs in tumor cells and thereby increase the efficacy of the treatment, either of conventional small molecular drugs or oligonucleotide based therapeutics. This review is focused on the cancer applications of cell penetrating peptides as delivery systems; different aspects of drug loading, cargoes and delivery are discussed together with methods for targeted delivery, activatable cell-penetrating peptides and transducible agents coupled to cell-penetrating peptides. PMID:24280701

  4. Universal penetration test apparatus with fluid penetration sensor

    DOEpatents

    Johnson, P.W.; Stampfer, J.F.; Bradley, O.D.

    1999-02-02

    A universal penetration test apparatus is described for measuring resistance of a material to a challenge fluid. The apparatus includes a pad saturated with the challenge fluid. The apparatus includes a compression assembly for compressing the material between the pad and a compression member. The apparatus also includes a sensor mechanism for automatically detecting when the challenge fluid penetrates the material. 23 figs.

  5. Universal penetration test apparatus with fluid penetration sensor

    DOEpatents

    Johnson, Phillip W.; Stampfer, Joseph F.; Bradley, Orvil D.

    1999-01-01

    A universal penetration test apparatus for measuring resistance of a material to a challenge fluid. The apparatus includes a pad saturated with the challenge fluid. The apparatus includes a compression assembly for compressing the material between the pad and a compression member. The apparatus also includes a sensor mechanism for automatically detecting when the challenge fluid penetrates the material.

  6. Top Sounder Ice Penetration

    NASA Astrophysics Data System (ADS)

    Porter, D. L.; Goemmer, S. A.; Sweeney, J. H.

    2014-12-01

    Ice draft measurements are made as part of normal operations for all US Navy submarines operating in the Arctic Ocean. The submarine ice draft data are unique in providing high resolution measurements over long transects of the ice covered ocean. The data has been used to document a multidecadal drop in ice thickness, and for validating and improving numerical sea-ice models. A submarine upward-looking sonar draft measurement is made by a sonar transducer mounted in the sail or deck of the submarine. An acoustic beam is transmitted upward through the water column, reflecting off the bottom of the sea ice and returning to the transducer. Ice thickness is estimated as the difference between the ship's depth (measured by pressure) and the acoustic range to the bottom of the ice estimated from the travel time of the sonar pulse. Digital recording systems can provide the return off the water-ice interface as well as returns that have penetrated the ice. Typically, only the first return from the ice hull is analyzed. Information regarding ice flow interstitial layers provides ice age information and may possibly be derived with the entire return signal. The approach being investigated is similar to that used in measuring bottom sediment layers and will involve measuring the echo level from the first interface, solving the reflection loss from that transmission, and employing reflection loss versus impedance mismatch to ascertain ice structure information.

  7. Electromagnetic Field Penetration Studies

    NASA Technical Reports Server (NTRS)

    Deshpande, M.D.

    2000-01-01

    A numerical method is presented to determine electromagnetic shielding effectiveness of rectangular enclosure with apertures on its wall used for input and output connections, control panels, visual-access windows, ventilation panels, etc. Expressing EM fields in terms of cavity Green's function inside the enclosure and the free space Green's function outside the enclosure, integral equations with aperture tangential electric fields as unknown variables are obtained by enforcing the continuity of tangential electric and magnetic fields across the apertures. Using the Method of Moments, the integral equations are solved for unknown aperture fields. From these aperture fields, the EM field inside a rectangular enclosure due to external electromagnetic sources are determined. Numerical results on electric field shielding of a rectangular cavity with a thin rectangular slot obtained using the present method are compared with the results obtained using simple transmission line technique for code validation. The present technique is applied to determine field penetration inside a Boeing-757 by approximating its passenger cabin as a rectangular cavity filled with a homogeneous medium and its passenger windows by rectangular apertures. Preliminary results for, two windows, one on each side of fuselage were considered. Numerical results for Boeing-757 at frequencies 26 MHz, 171-175 MHz, and 428-432 MHz are presented.

  8. Sidewall penetrator for oil wells

    NASA Technical Reports Server (NTRS)

    Collins, E. R., Jr.

    1981-01-01

    Penetrator bores horizontal holes in well casing to increase trapped oil drainage. Several penetrators operated by common drive are inserted into well at once. Shaft, made from spiraling cable, rotates and thrusts simultaneously through rigid curvilinear guide tube forcing bit through casing into strata. Device pierces more deeply than armor-piercing bullets and shaped explosive charges.

  9. Ground-penetrating radar methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ground-penetrating radar geophysical methods are finding greater and greater use in agriculture. With the ground-penetrating radar (GPR) method, an electromagnetic radio energy (radar) pulse is directed into the subsurface, followed by measurement of the elapsed time taken by the radar signal as it ...

  10. Static penetration resistance of soils

    NASA Technical Reports Server (NTRS)

    Durgunoglu, H. T.; Mitchell, J. K.

    1973-01-01

    Model test results were used to define the failure mechanism associated with the static penetration resistance of cohesionless and low-cohesion soils. Knowledge of this mechanism has permitted the development of a new analytical method for calculating the ultimate penetration resistance which explicitly accounts for penetrometer base apex angle and roughness, soil friction angle, and the ratio of penetration depth to base width. Curves relating the bearing capacity factors to the soil friction angle are presented for failure in general shear. Strength parameters and penetrometer interaction properties of a fine sand were determined and used as the basis for prediction of the penetration resistance encountered by wedge, cone, and flat-ended penetrometers of different surface roughness using the proposed analytical method. Because of the close agreement between predicted values and values measured in laboratory tests, it appears possible to deduce in-situ soil strength parameters and their variation with depth from the results of static penetration tests.

  11. An Earth Penetrating Modeling Assessment

    SciTech Connect

    Stokes, E; Yarrington, P; Glenn, L

    2005-06-21

    Documentation of a study to assess the capability of computer codes to predict lateral loads on earth penetrating projectiles under conditions of non-normal impact. Calculations simulated a set of small scale penetration tests into concrete targets with oblique faces at angles of 15 and 30 degrees to the line-of-flight. Predictive codes used by the various calculational teams cover a wide range of modeling approaches from approximate techniques, such as cavity expansion, to numerical methods, such as finite element codes. The modeling assessment was performed under the auspices of the Phenomenology Integrated Product Team (PIPT) for the Robust Nuclear Earth Penetrator Program (RNEP). Funding for the penetration experiments and modeling was provided by multiple earth penetrator programs.

  12. Skin penetration of silica microparticles.

    PubMed

    Boonen, J; Baert, B; Lambert, J; De Spiegeleer, B

    2011-06-01

    Knowledge about skin penetration of nano- and microparticles is essential for the development of particle-core drug delivery systems and toxicology. A large number of studies have been devoted to metallic particle penetration. However, little work has been published about the importance of chemical material properties of the particles and the skin penetration effect of the applied formulation. Here, we investigated the penetration of 3 microm silica particles in water and in a 65% ethanolic plant extract on ex vivo human skin using scanning electron microscopy. Contrary to most other microsphere skin studies, we observed for the first time that 3 microm silica particles can penetrate the living epidermis. Moreover, when formulated in the ethanolic medium, particles even reach the dermis. The deviating chemical properties of silica compared to previously investigated microparticles (titanium dioxide, zinc oxide) and confounding effect of the formulation in which the silica microparticles are presented, is thus demonstrated. PMID:21699089

  13. Factors associated with graft survival and endothelial cell density after Descemet’s stripping automated endothelial keratoplasty

    PubMed Central

    Ishii, Nobuhito; Yamaguchi, Takefumi; Yazu, Hiroyuki; Satake, Yoshiyuki; Yoshida, Akitoshi; Shimazaki, Jun

    2016-01-01

    Postoperative endothelial cell loss leads to graft failure after corneal transplantation, and is one of the important issues for long-term prognosis. The objective of this study was to identify clinical factors affecting graft survival and postoperative endothelial cell density (ECD) after Descemet’s stripping automated endothelial keratoplasty (DSAEK). A total of 198 consecutive Japanese patients (225 eyes) who underwent DSAEK were analysed using Cox proportional hazard regression and multiple linear regression models. The candidate factors included recipient age; gender; diagnosis; pre-existing iris damage state, scored based on its severity; the number of previous intraocular surgeries; graft ECD; graft diameter; simultaneous cataract surgery; surgeons experience; intraoperative iris damage; postoperative rebubbling; and graft rejection. Eyes with higher pre-existing iris damage score and more number of previous intraocular surgery had a significantly higher risk of graft failure (HR = 8.53; P < 0.0001, and HR = 2.66; P = 0.026, respectively). Higher pre-existing iris damage score, lower graft ECD, and smaller graft diameter were identified as significant predisposing factors for lower postoperative ECD. The results show that iris damage status before DSAEK may be clinically useful in predicting the postoperative course. Avoiding intraoperative iris damage, especially in eyes with low ECD can change the prognosis of future DSAEK. PMID:27121659

  14. A simple rescue maneuver for unfolding and centering a tightly rolled graft in Descemet membrane endothelial keratoplasty.

    PubMed

    Droutsas, Konstantinos; Bertelmann, Thomas; Schroeder, Frank M; Papaconstantinou, Dimitrios; Sekundo, Walter

    2014-01-01

    A 74-year-old man underwent Descemet membrane endothelial keratoplasty (DMEK) for endothelial decompensation due to Fuchs endothelial dystrophy. After descemetorhexis, the DMEK graft was inserted into the anterior chamber. However, unfolding of the graft was not possible as the graft was very tightly rolled together and the anterior chamber deep. After placing a 30G-cannula connected to an air-filled syringe inside the roll's lumen, a small air bubble was injected, which allowed the roll to open up, until it assumed a "taco" configuration around the bubble. Then, the graft was centered by pressing the posterior part of the roll against, and sweeping it over the iris. In the present case a "tight" DMEK roll was successfully unfolded by injection of a single air bubble into the roll's lumen and centered by a "sweeping" the partialy unfolded graft over the iris. This technique allowed a controlled unfolding and centering of the DMEK graft with limited trauma to the donor endothelium and may be applied in cases where other less traumatic maneuvers are not successful. PMID:25368513

  15. Modified tectonic keratoplasty with minimal corneal graft for corneal perforation in severe Stevens - Johnson syndrome: a case series study

    PubMed Central

    2014-01-01

    Background Corneal perforation in severe Stevens-Johnson syndrome (SJS) presenting great therapeutic difficulties, the imperative corneal transplantation always result in graft failure and repeated recurrence of perforation. The aim of this study was to evaluate the effectiveness of a modified small tectonic keratoplasty (MSTK) with minimal corneal graft in the management of refractory corneal perforation in severe SJS. Methods Refractory corneal perforations in ten patients (10 eyes) with severe SJS were mended with a minimal corneal patch graft, under the guidance of anterior chamber optical coherence tomography, combined with conjunctival flap covering. The outcome measures included healing of the corneal perforation, survival of the corneal graft and conjunctival flap, relevant complications, and improvement in visual acuity. Results Corneal perforation healed, and global integrity was achieved in all eyes. No immune rejection or graft melting was detected. Retraction of conjunctival flap occurred in one eye, which was treated with additional procedure. Visual acuity improved in six eyes (60%), unchanged in three eyes (30%) and declined in one eye (10%). Conclusions The MSTK combined with conjunctival flap covering seems to be effective for refractory corneal perforation in severe SJS. PMID:25102918

  16. Projectile penetration into ballistic gelatin.

    PubMed

    Swain, M V; Kieser, D C; Shah, S; Kieser, J A

    2014-01-01

    Ballistic gelatin is frequently used as a model for soft biological tissues that experience projectile impact. In this paper we investigate the response of a number of gelatin materials to the penetration of spherical steel projectiles (7 to 11mm diameter) with a range of lower impacting velocities (<120m/s). The results of sphere penetration depth versus projectile velocity are found to be linear for all systems above a certain threshold velocity required for initiating penetration. The data for a specific material impacted with different diameter spheres were able to be condensed to a single curve when the penetration depth was normalised by the projectile diameter. When the results are compared with a number of predictive relationships available in the literature, it is found that over the range of projectiles and compositions used, the results fit a simple relationship that takes into account the projectile diameter, the threshold velocity for penetration into the gelatin and a value of the shear modulus of the gelatin estimated from the threshold velocity for penetration. The normalised depth is found to fit the elastic Froude number when this is modified to allow for a threshold impact velocity. The normalised penetration data are found to best fit this modified elastic Froude number with a slope of 1/2 instead of 1/3 as suggested by Akers and Belmonte (2006). Possible explanations for this difference are discussed. PMID:24184862

  17. Cooperative Transmembrane Penetration of Nanoparticles

    PubMed Central

    Zhang, Haizhen; Ji, Qiuju; Huang, Changjin; Zhang, Sulin; Yuan, Bing; Yang, Kai; Ma, Yu-qiang

    2015-01-01

    Physical penetration of lipid bilayer membranes presents an alternative pathway for cellular delivery of nanoparticles (NPs) besides endocytosis. NPs delivered through this pathway could reach the cytoplasm, thereby opening the possibility of organelle-specific targeting. Herein we perform dissipative particle dynamics simulations to elucidate the transmembrane penetration mechanisms of multiple NPs. Our simulations demonstrate that NPs’ translocation proceeds in a cooperative manner, where the interplay of the quantity and surface chemistry of the NPs regulates the translocation efficiency. For NPs with hydrophilic surfaces, the increase of particle quantity facilitates penetration, while for NPs with partly or totally hydrophobic surfaces, the opposite highly possibly holds. Moreover, a set of interesting cooperative ways, such as aggregation, aggregation-dispersion, and aggregation-dispersion-reaggregation of the NPs, are observed during the penetration process. We find that the penetration behaviors of multiple NPs are mostly dominated by the changes of the NP-membrane force components in the membrane plane direction, in addition to that in the penetration direction, suggesting a different interaction mechanism between the multiple NPs and the membrane compared with the one-NP case. These results provide a fundamental understanding in the underlying mechanisms of cooperative penetration of NPs, and shed light on the NP-based drug and gene delivery. PMID:26013284

  18. DRAINAGE PIPE DETECTOR: GROUND PENETRATING RADAR SHOWS PROMISE IN LOCATING BURIED SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the more frustrating problems confronting farmers and land improvement contractors in the Midwestern United States involves locating buried agricultural drainage pipes. Conventional geophysical methods, particularly ground penetrating radar (GPR), presently being used for environmental and co...

  19. Inspecting the reactor vessel penetrations

    SciTech Connect

    Bodson, F.; Fleming, K.W.

    1995-08-01

    The susceptibility of Alloy 600 to Primary Water Stress Corrosion Cracking (PWSCC) continues to plague nuclear power plants. Recently, the problem of PWSCC cracking has manifested itself in Control Rod Drive Mechanism (CRDM) head penetrations in nuclear plants in Europe. Framatome has been extensively involved in the performance of both inspections and repairs of CRDM head penetrations at Electricite de France (EdF) plants. B and W Nuclear Technologies (BWNT), building on Framatome technology, has developed a fully integrated service package and robotic manipulator to inspect and repair CRDM head penetrations for US utilities. Reactor vessel bottom penetration are also made of Alloy 600 and to tackle this potential PWSCC problem at EdF plants, Framatome has been performing specific inspections in order to detect the appearance of the phenomenon. This paper describes the overall range of inspection techniques and toolings developed to address these issues.

  20. Ground Penetrating Radar, Barrow, Alaska

    SciTech Connect

    John Peterson

    2015-03-06

    This is 500 MHz Ground Penetrating Radar collected along the AB Line in Intensive Site 1 beginning in October 2012 and collected along L2 in Intensive Site 0 beginning in September 2011. Both continue to the present.

  1. Investigations into Monochloramine Biofilm Penetration

    EPA Science Inventory

    Biofilm in drinking water systems is undesirable. Free chlorine and monochloramine are commonly used as secondary drinking water disinfectants, but monochloramine is perceived to penetrate biofilm better than free chlorine. However, this hypothesis remains unconfirmed by direct b...

  2. Cement penetration after patella venting.

    PubMed

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement. PMID:19010682

  3. LeciPlex, invasomes, and liposomes: A skin penetration study.

    PubMed

    Shah, Sanket M; Ashtikar, Mukul; Jain, Ankitkumar S; Makhija, Dinesh T; Nikam, Yuvraj; Gude, Rajiv P; Steiniger, Frank; Jagtap, Aarti A; Nagarsenker, Mangal S; Fahr, Alfred

    2015-07-25

    The present study compares three vesicular systems, cationic LeciPlex, invasomes, and conventional liposomes for their ability to deliver drugs deep into the skin. Skin penetration ability of the three vesicular systems was studied for two drugs namely idebenone (antioxidant/anticancer) and azelaic acid (antiacne). All systems showed sizes in nanometer range with small polydispersity indices. Vesicular systems were characterized by CryoTEM studies to understand the differences in morphology of the vesicular systems. Ex vivo human skin penetration studies suggested a pattern in penetration of drugs in different layers of the skin: LeciPlex showed higher penetration for idebenone whereas invasomes showed higher penetration of azelaic acid. Ex vivo study using a fluorescent dye (DiI) was performed to understand the differences in the penetration behavior of the three vesicular systems on excised human skin. In vitro cytotoxicity studies on B16F10 melanoma cell lines revealed, when loaded with idebenone, LeciPlex formulations had the superior activity followed by invasomes and liposomes. In vitro antimicrobial study of azelaic acid loaded systems on Propionibacterium acne revealed high antimicrobial activity for DDAB leciplex followed by almost equal activity for invasomes and CTAB LeciPlex followed by liposomes. Whereas antiacne efficacy study in rats for azelaic acid loaded systems, invasomes exhibited the best antiacne efficacy followed by liposomes and LeciPlex. PMID:26002568

  4. Penetration through the Skin Barrier.

    PubMed

    Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke

    2016-01-01

    The skin is a strong and flexible organ with barrier properties essential for maintaining homeostasis and thereby human life. Characterizing this barrier is the ability to prevent some chemicals from crossing the barrier while allowing others, including medicinal products, to pass at varying rates. During recent decades, the latter has received increased attention as a route for intentionally delivering drugs to patients. This has stimulated research in methods for sampling, measuring and predicting percutaneous penetration. Previous chapters have described how different endogenous, genetic and exogenous factors may affect barrier characteristics. The present chapter introduces the theory for barrier penetration (Fick's law), and describes and discusses different methods for measuring the kinetics of percutaneous penetration of chemicals, including in vitro methods (static and flow-through diffusion cells) as well as in vivo methods (microdialysis and microperfusion). Then follows a discussion with examples of how different characteristics of the skin (age, site and integrity) and of the penetrants (size, solubility, ionization, logPow and vehicles) affect the kinetics of percutaneous penetration. Finally, a short discussion of the advantages and challenges of each method is provided, which will hopefully allow the reader to improve decision making and treatment planning, as well as the evaluation of experimental studies of percutaneous penetration of chemicals. PMID:26844902

  5. Demonstration of survivable space penetrator

    NASA Astrophysics Data System (ADS)

    Church, Philip; Huntington-Thresher, William; Bruce, Alan; Penny, Nick; Smith, Alan; Gowan, Rob

    2012-03-01

    This work was performed in support of MoonLITE which is a proposed UK space mission to the moon. The basic premise is to deploy 4 instrumented penetrators, one each on the near-side, farside and at the poles of the moon, with an impact velocity of approximately 300m/s. The primary science aims are to set up a passive seismometer network, investigate the presence of water and volatiles and determine thermal gradients in the lunar soil (i.e. regolith). A key requirement is that the penetrator shell survives the impact together with the instrument payload and supporting subsystems. The material chosen for the penetrator shell was 7075 aluminium alloy, which is a good compromise between high compressive strength and low mass. The baseline penetrator design was evaluated and refined using the DYNA3D hydrocode to determine the survivability of the penetrator in sand at an impact velocity of 300m/s and an attack angle of 8°. The simulations predicted that the penetrator design would survive this severe impact condition which was confirmed by experiments on the Pendine rocket test track.

  6. Validation of an endothelial roll preparation for Descemet Membrane Endothelial Keratoplasty by a cornea bank using "no touch" dissection technique.

    PubMed

    Marty, Anne-Sophie; Burillon, Carole; Desanlis, Adeline; Damour, Odile; Kocaba, Viridiana; Auxenfans, Céline

    2016-06-01

    Descemet Membrane Endothelial Keratoplasty (DMEK) selectively replaces the damaged posterior part of the cornea. However, the DMEK technique relies on a manually-performed dissection that is time-consuming, requires training and presents a potential risk of endothelial graft damages leading to surgery postponement when performed by surgeons in the operative room. To validate precut corneal tissue preparation for DMEK provided by a cornea bank in order to supply a quality and security precut endothelial tissue. The protocol was a technology transfer from the Netherlands Institute for Innovative Ocular Surgery (NIIOS) to Lyon Cornea Bank, after formation in NIIOS to the DMEK "no touch" dissection technique. The technique has been validated in selected conditions (materials, microscope) and after a learning curve, cornea bank technicians prepared endothelial tissue for DMEK. Endothelial cells densities (ECD) were evaluated before and after preparation, after storage and transport to the surgery room. Microbiological and histological controls have been done. Twenty corneas were manually dissected; 18 without tears. Nineteen endothelial grafts formed a double roll. The ECD loss after cutting was 3.3 % (n = 19). After transportation 7 days later, we found an ECD loss of 25 % (n = 12). Three days after cutting and transportation, we found 2.1 % of ECD loss (n = 7). Histology found an endothelial cells monolayer lying on Descemet membrane. The mean thickness was 12 ± 2.2 µm (n = 4). No microbial contamination was found (n = 19). Endothelial roll stability has been validated at 3 days in our cornea bank. Cornea bank technicians trained can deliver to surgeons an ECD controlled, safety and ready to use endothelial tissue, for DMEK by "no touch" technique, allowing time saving, quality and security for surgeons. PMID:26934895

  7. Correlation of anterior segment optical coherence tomography measurements with graft trephine diameter following descemet stripping automated endothelial keratoplasty

    PubMed Central

    2012-01-01

    Background To assess repeatability of the Zhongshan Assessment Program (ZAP) software measurement of Anterior Segment Optical Coherence Tomography (ASOCT) images and correlate with graft trephine diameter following Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) Methods Retrospectively evaluated interventional case series. 121 consecutive eyes undergoing DSAEK over a 26 month period underwent ASOCT imaging 1month after their surgery. ASOCT images were processed using ZAP software which measured the graft and cornea parameters including anterior and posterior graft arc length and cord length, posterior cornea arc length (PCAL) and anterior chamber width. Results The graft measurements showed good repeatability on ASOCT using ZAP with high intra class coefficient and small variation in the coefficient of variation. On ASOCT, the mean recipient PCAL was 12.99+/−0.69mm and the anterior chamber width was 11.16+/−0.57mm. The mean Graft anterior arc length was 9.69+/−0.66mm and the mean Graft anterior cord length was 8.92+/−2.94mm. The mean graft posterior arc length was 9.24+/−0.75mm and the mean graft posterior cord length was 8.15+/−0.57mm. Graft posterior arc length (rho=0.788, p< 0.001) correlated best with intra-operative graft trephine diameter. The mean ratio of posterior graft arc length to PCAL was 0.712 +/− 0.056. Conclusions We have validated the repeatability of the ZAP software for DSAEK graft measurements from ASOCT images and shown that the graft arc length parameters calculated from the ASOCT images correlate well with the intra-operative graft trephine diameter. This software may help surgeons determine the optimal DSAEK graft size based on pre-operative ASOCT measurements of the recipient eye. PMID:22824516

  8. Inhibition of RelA expression via RNA interference induces immune tolerance in a rat keratoplasty model.

    PubMed

    Yang, Jize; Feng, Songfu; Yi, Guoguo; Wu, Wei; Yi, Ruiwen; Lu, Xiaohe; Xu, Wanfu; Qiu, Haijiang

    2016-05-01

    RelA, the most important regulator of NF-kB activity, and its mechanisms in keratoplasty immune rejection have not been fully investigated. In the present study, lentivirus-mediated silencing of RelA expression in a bone marrow-derived dendritic cell (BMDC) model was tested. The BMDCs were transfected with RelA-shRNA to induce an immature, maturation-resistant and tolerogenic phenotype, while not significantly changing IFN-γ, IL-10 and IL-17 expression. A fully allogeneic rat cornea transplant model was established for in vivo studies. The allograft mean survival time (MST) of lv-shRelA-DC injection groups were significantly longer than the untreated BMDC group and control group. The corneal opacity and neovascularization scale of the lv-shRelA-DC injection groups were slight compared to pair control others. Postoperative flow cytometric analysis revealed that the percentage of Treg positive cells was dramatically increased in animals that received an lv-shRelA-DC injection. ELISA and qRT-PCR analyses of serum showed that IFN-γ and IL-17 expression were suppressed by lv-shRelA-DC treatement. In vivo experiments demonstrated that IL-10 induced immunosuppression was partly attributed to injection of lv-shRelA-DC throughout the experiment, differing from the general anti-inflammatory factors. Luciferase and Chromatin IP evaluation showed that RelA knockdown in BMDCs significantly reduces DNA binding to IFN-γ, IL-10 and the IL-17 promoter and inhibited of transcriptional activity. Taken together, this study illustrates a significant role of RelA in mediating the corneal neovascularization by affecting IL-17 expression. Our comprehensive analysis shows that the significant role of RelA provides a novel and feasible therapeutic approach for the prevention of corneal allograft rejection. PMID:27062711

  9. Global cell-by-cell evaluation of endothelial viability after two methods of graft preparation in Descemet membrane endothelial keratoplasty

    PubMed Central

    Bhogal, Maninder; Balda, Maria S; Matter, Karl; Allan, Bruce D

    2016-01-01

    Purpose To describe a novel method of global cell viability assessment for Descemet membrane endothelial keratoplasty (DMEK) and the comparison of two contemporary methods of donor tissue preparation. Methods DMEK transplants were prepared using two different methods: liquid bubble separation and manual peeling (n=8 each group). Samples were incubated with Hoechst, calcein-AM and ethidium homodimer prior to mounting on a curved imaging chamber. Z-stacked fluorescence microscopy images were combined to produce an in-focus global image capable of resolving all cell nuclei. Image processing software was used to define a calcein-positive live cell area, count all cell nuclei within this area and subtract ethidium-positive dead cells to derive the total viable endothelial cell count. Corrected global cell density was calculated by dividing the number of viable cells by the graft area, which had been corrected for imaging a curved surface. Results Corrected global cell density was lower than the central endothelial cell density in both groups: 85.5% of the pre-preparation central endothelial cell density in the peel group and 75.8% in the bubble group. Corrected global cell density was significantly lower in the liquid bubble separation group than in the peel group (p=0.04). Conclusions Eye bank estimations of central endothelial cell density overestimate true cell density after graft preparation in DMEK. A peel method is less damaging and more consistent than a liquid bubble method. Cell loss correlated strongly with the degree of stromal hydration prior to bubble separation in the liquid bubble group. PMID:26740609

  10. Photochemical tissue penetration via photosensitizer for effective drug penetration in a non-vascular tumor.

    PubMed

    Min, Daehong; Jeong, Dooyong; Choi, Myung Gyu; Na, Kun

    2015-06-01

    To improve the tissue penetration efficiency (PE%) of hydrophilic-drugs in non-vascular drug eluting stents (DES), we designed photochemical tissue penetration (PTP) invested DES (PTP-DES). The PTP technology was applied to the stent as a covering membrane to generate singlet oxygen. Singlet oxygen damages the epithelial layer, so the PE% of released drugs could be improved. To prepare the PTP-DES membrane, chlorin e6 (Ce6, photosensitizer) was incorporated in a gemcitabine (GEM) eluting polyurethane (PU) membrane (Ce6-GEM-PU). Ce6-GEM-PU has smooth surface that is ∼40 μm thick. The photoactivity of Ce6 was maintained for 2 weeks (in vitro GEM releasing period). In a separate cell culture system, both 1.5 folds higher PE% and an improved tumor cell growth inhibition effect were shown after light exposure. Additionally, in tissue penetration experimental system, 2 folds increased in the PE% of GEM was induced by laser exposure at 80 J/cm2. Additionally, improved PE% of hydrophilic molecules (Fluorescein and GEM) was confirmed in colon tumor bearing mice. Consequentially, tumor growth, when implanted with Ce6-GEM-PU, was effectively inhibited without significant side effects. Based on these results, we believe that the PTP-DES system has great potential for improving the therapeutic effect of conventional DES. PMID:25818454

  11. Foliar penetration enhanced by biosurfactant rhamnolipid.

    PubMed

    Liu, Haojing; Shao, Bing; Long, Xuwei; Yao, Yang; Meng, Qin

    2016-09-01

    With recent environmental and health concerns, biosurfactants have obtained increasing interest in replacing conventional surfactants for diverse applications. In agriculture, the use of surfactant in stimulating foliar uptake is mainly for wetting leaf surface, resisting deposition/evaporation, enhancing penetration across cuticular membrane (CM) and translocation. This paper aimed to address the improved foliar uptake by rhamnolipid (RL) in comparison with the currently used alkyl polyglucoside (APG). As found, compared with APG at 900mg/L (1×critical micellar concentration, CMC), RL at a much lower concentration of 50mg/L (1×CMC) showed much better wettability and surface activity, indicative of its high effectiveness as surfactants. Its performance on resistance to deposition and evaporation was at least as same as APG. Moreover, RL could significantly improve the penetration of herbicide glyphosate and other two small water-soluble molecules (phenol red and Fe(2+)) across CM at an equivalent efficiency as APG at 1×CMC. Finally, the greatly enhanced herbicidal actitivity of glyphosate on greenhouse plants confirmed that RL and APG could both enhance the foliar uptake including translocation. Overall, RL should be more applicable than APG in agriculture due to its more promising properties on health/environmental friendliness. PMID:27281240

  12. Objective, comparative assessment of the penetration depth of temporal-focusing microscopy for imaging various organs

    NASA Astrophysics Data System (ADS)

    Rowlands, Christopher J.; Bruns, Oliver T.; Bawendi, Moungi G.; So, Peter T. C.

    2015-06-01

    Temporal focusing is a technique for performing axially resolved widefield multiphoton microscopy with a large field of view. Despite significant advantages over conventional point-scanning multiphoton microscopy in terms of imaging speed, the need to collect the whole image simultaneously means that it is expected to achieve a lower penetration depth in common biological samples compared to point-scanning. We assess the penetration depth using a rigorous objective criterion based on the modulation transfer function, comparing it to point-scanning multiphoton microscopy. Measurements are performed in a variety of mouse organs in order to provide practical guidance as to the achievable penetration depth for both imaging techniques. It is found that two-photon scanning microscopy has approximately twice the penetration depth of temporal-focusing microscopy, and that penetration depth is organ-specific; the heart has the lowest penetration depth, followed by the liver, lungs, and kidneys, then the spleen, and finally white adipose tissue.

  13. Objective, comparative assessment of the penetration depth of temporal-focusing microscopy for imaging various organs

    PubMed Central

    Rowlands, Christopher J.; Bruns, Oliver T.; Bawendi, Moungi G.; So, Peter T. C.

    2015-01-01

    Abstract. Temporal focusing is a technique for performing axially resolved widefield multiphoton microscopy with a large field of view. Despite significant advantages over conventional point-scanning multiphoton microscopy in terms of imaging speed, the need to collect the whole image simultaneously means that it is expected to achieve a lower penetration depth in common biological samples compared to point-scanning. We assess the penetration depth using a rigorous objective criterion based on the modulation transfer function, comparing it to point-scanning multiphoton microscopy. Measurements are performed in a variety of mouse organs in order to provide practical guidance as to the achievable penetration depth for both imaging techniques. It is found that two-photon scanning microscopy has approximately twice the penetration depth of temporal-focusing microscopy, and that penetration depth is organ-specific; the heart has the lowest penetration depth, followed by the liver, lungs, and kidneys, then the spleen, and finally white adipose tissue. PMID:25844509

  14. Resuscitative thoracotomy in penetrating trauma.

    PubMed

    Fairfax, Lindsay M; Hsee, Li; Civil, Ian D

    2015-06-01

    The resuscitative thoracotomy (RT) is an important procedure in the management of penetrating trauma. As it is performed only in patients with peri-arrest physiology or overt cardiac arrest, survival is low. Experience is also quite variable depending on volume of penetrating trauma in a particular region. Survival ranges from 0% to as high as 89% depending on patient selection, available resources, and location of RT (operating or emergency rooms). In this article, published guidelines are reviewed as well as outcomes. Technical considerations of RT and well as proper training, personnel, and location are also discussed. PMID:25342073

  15. Mars surface penetrator: System description

    NASA Technical Reports Server (NTRS)

    Manning, L. A. (Editor)

    1977-01-01

    A point design of a penetrator system for a Mars mission is described. A strawman payload which is to conduct measurements of geophysical and meteorological parameters is included in the design. The subsystems used in the point design are delineated in terms of power, mass, volume, data, and functional modes. The prospects for survival of the rigors of emplacement are described. Data handling and communications plans are presented to allow consideration of the requirements placed by the penetrator on the orbiter and ground operations. The point design is technically feasible and the payload selection scientifically desirable.

  16. Detection and sizing of defects in control rod drive mechanism penetrations using eddy current and ultrasonics

    SciTech Connect

    Light, G.M.; Fisher, J.L.; Tennis, R.F.; Stolte, J.S.; Hendrix, G.J.

    1996-08-01

    Over the last two years, concern has been generated about the capabilities of performing nondestructive evaluation (NDE) of the closure-head penetrations in nuclear-reactor pressure vessels. These penetrations are primarily for instrumentation and control rod drive mechanisms (CRDMs) and are usually thick-walled Inconel tubes, which are shrink-fitted into the steel closure head. The penetrations are then welded between the outside surface of the penetration and the inside surface of the closure head. Stress corrosion cracks initiating at the inner surface of the penetration have been reported at several plants. Through-wall cracks in the CRDM penetration or CRDM weld could lead to loss of coolant in the reactor vessel. The CRDM penetration presents a complex inspection geometry for conventional NDE techniques. A thermal sleeve, through which pass the mechanical linkages for operating the control rods, is inserted into the penetration in such a way that only a small annulus (nominally 3 mm) exists between the thermal sleeve and inside surface of the penetration. Ultrasonic (UT) and eddy current testing (ET) techniques that could be used to provide defect detection and sizing capability were investigated. This paper describes the ET and UT techniques, the probes developed, and the results obtained using these probes and techniques on CRDM penetration mock-ups.

  17. Simulation of laser penetration efficiency

    NASA Astrophysics Data System (ADS)

    Semak, V. V.; Miller, T. F.

    2013-09-01

    The results of numerical simulation of laser beam interaction with a hypothetical metallic material with properties similar to a steel alloy are reported. The numerical simulation was performed using a physical model that includes detailed consideration of surface evaporation, evaporative cooling of the surface and evaporation recoil induced melt ejection. The laser beam ‘penetration’ is considered in terms of melting through the sample or drilling through the sample due to both evaporation and recoil ejection of material. As a demonstration of the predictive capabilities of the model, the average velocity of penetration through a material with steel-like properties is numerically predicted for various laser interaction parameters such as, laser beam radius, laser pulse duration (including CW regime), laser pulse energy and pulse repetition. In particular, the average penetration velocities through a sample due to melting are compared for pulsed and CW lasers of the same power. For the sake of another demonstration of penetration simulation, the temporal dynamics of the position of melt front relative to the sample surface irradiated by a laser beam was computed for different laser pulse repetition rates and constant average laser power. An illustration of the penetration efficiency (W parameter) defined as the amount of energy per unit volume delivered into a target in order to achieve either melting of drilling through a target wall is shown in a wide range of laser pulse parameters covering regimes corresponding to domination of melting through and drilling through.

  18. Magnetically-Guided Penetrant Applicator

    NASA Technical Reports Server (NTRS)

    Molina, Orlando G.

    1990-01-01

    Small wheeled vehicle moved inside nonmagnetic enclosure. Miniature magnetically guided truck uses foam-rubber sponge pads to apply penetrant fluid for inspection of welds in hidden surfaces of nonmagnetic tubes. Risk of explosion less than if electric motor used to drive vehicle. Inexpensive to make and made in range of sizes.

  19. Percutaneous penetration--methodological considerations.

    PubMed

    Holmgaard, Rikke; Benfeldt, Eva; Nielsen, Jesper B

    2014-07-01

    Studies on percutaneous penetration are needed to assess the hazards after unintended occupational skin exposures to industrial products as well as the efficacy after intended consumer exposure to topically applied medicinal or cosmetic products. During recent decades, a number of methods have been developed to replace methods involving experimental animals. The results obtained from these methods are decided not only by the chemical or product tested, but to a significant degree also by the experimental set-up and decisions made by the investigator during the planning phase. The present MiniReview discusses some of the existing and well-known experimental in vitro and in vivo methods for studies of percutaneous penetration together with some more recent and promising methods. After this, some considerations and recommendations about advantages and limitations of the different methods and their relevance for the prediction of percutaneous penetration are given. Which method to prefer will depend on the product to be tested and the question asked. Regulatory guidelines exist for studies on percutaneous penetration, but researchers as well as regulatory bodies need to pay specific attention to the vehicles and solvents used in donor and sampling fluids so that it reflects in-use conditions as closely as possible. Based on available experimental data, mathematical models have been developed to aid predictions of skin penetration. The authors question the general use of the present mathematical models in hazard assessment, as they seem to ignore outliers among chemicals as well as the heterogeneity of skin barrier properties and skin conditions within the exposed populations. PMID:24373389

  20. Penetration below a convective zone

    NASA Astrophysics Data System (ADS)

    Hurlburt, Neal E.; Toomre, Juri; Massaguer, Josep M.; Zahn, Jean-Paul

    1994-01-01

    Two-dimensional numerical simulations are used to investigate how fully compressible nonlinear convection penetrates into a stably stratified zone beneath a stellar convection zone. Estimates are obtained of the extent of penetration as the relative stability S of the stable to the unstable zone is varied over a broad range. The model deals with a perfect gas possessing a constant dynamic viscosity. The dynamics is dominated by downward-directed plumes which can extend far into the stable material and which can lead to the excitation of a broad spectrum of internal gravity waves in the lower stable zone. The convection is highly time dependent, with the close coupling between the lateral swaying of the plumes and the internal gravity waves they generate serving to modulate the strength of the convection. The depth of penetration delta, determined by the position where the time-averaged kinetic flux has its first zero in the stable layer, is controlled by a balance between the kinetic energy carried into the stable layer by the plumes and the buoyancy braking they experience there. A passive scalar is introduced into the unstable layer to evaluate the transport of chemical species downward. Such a tracer is effectively mixed within a few convective overturning times down to a depth of delta within the stable layer. Analytical estimates based on simple scaling laws are used to interpret the variation of delta with S, showing that it first involves an interval of adiabatic penetration if the local Peclet number of the convection exceeds unity, followed by a further thermal adjustment layer, the depths of each interval scaling in turn as S-1 and S-1/4. These estimates are in accord with the penetration results from the simulations.

  1. Akon - A Penetrator for Europa

    NASA Astrophysics Data System (ADS)

    Jones, Geraint

    2016-04-01

    Jupiter's moon Europa is one of the most intriguing objects in our Solar System. This 2000km-wide body has a geologically young solid water ice crust that is believed to cover a global ocean of liquid water. The presence of this ocean, together with a source of heating through tidal forces, make Europa a conceivable location for extraterrestrial life. The science case for exploring all aspects of this icy world is compelling. NASA has selected the Europa Mission (formerly Europa Clipper) to study Europa in detail in the 2020s through multiple flybys, and ESA's JUICE mission will perform two flybys of the body in the 2030s. The US agency has extended to the European Space Agency an invitation to provide a contribution to their mission. European scientists interested in Europa science and exploration are currently organizing themselves, in the framework of a coordinated Europa M5 Inititative to study concurrently the main options for this ESA contribution, from a simple addition of individual instruments to the NASA spacecraft, to a lander to investigate Europa's surface in situ. A high speed lander - a penetrator - is by far the most promising technology to achieve this latter option within the anticipated mass constraints, and studies of such a hard lander, many funded by ESA, are now at an advanced level. An international team to formally propose an Europa penetrator to ESA in response to the anticipated ESA M5 call is growing. The working title of this proposal is Akon (Άκων), named after the highly accurate javelin gifted to Europa by Zeus in ancient Greek mythology. We present plans for the Akon penetrator, which would impact Europa's surface at several hundred metres per second, and travel up to several metres into the moon's subsurface. To achieve this, the penetrator would be delivered to the surface by a dedicated descent module, to be destroyed on impact following release of the penetrator above the surface. It is planned that the instruments to be

  2. Decomposing Composing Conventions.

    ERIC Educational Resources Information Center

    Beers, Terry

    Recent research has invited critiques of the authoritative descriptions of composing found in many rhetoric textbooks. The concept of "convention" may be especially useful in rethinking the teleological basis of these textbook descriptions. Conventions found in composition textbooks need to be unmasked as arbitrary concepts which serve to…

  3. [Penetrating injuries to the pelvis].

    PubMed

    Doll, D; Lenz, S; Exadaktylos, A K; Stettbacher, A; Degiannis, E; Düsel, W; Siewert, J R

    2006-09-01

    As criminality and weapon use increase, general and military surgeons are increasingly confronted with penetrating pelvic injuries both at home and on peacekeeping missions. Penetrating injuries to the iliac vascular axis are associated with considerable mortality, and thus the majority of these emergency patients arrive in a state of deep hypovolemic shock. Concomitant bowel injuries are present in one of five cases, resulting in contamination of the damaged area. Surgical options are simple lateral repair, ligation of the veins, temporary shunt insertion, and prosthetic graft interposition in the injured artery. In extremis ligation of the common or external iliac artery may be the only option to save the patient's life. Surgeons must be aware that damage control surgery and related methods may be needed early on to enable patient survival. PMID:16906417

  4. Weld penetration and defect control

    SciTech Connect

    Chin, B.A.

    1992-05-15

    Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.

  5. Jeeps Penetrating a Hostile Desert

    ERIC Educational Resources Information Center

    Bailey, Herb

    2009-01-01

    Several jeeps are poised at base camp on the edge of a desert aiming to escort one of them as far as possible into the desert, while the others return to camp. They all have full tanks of gas and share their fuel to maximize penetration. In a friendly desert it is best to leave caches of fuel along the way to help returning jeeps. We solve the…

  6. Penetrating eye injury in war.

    PubMed

    Biehl, J W; Valdez, J; Hemady, R K; Steidl, S M; Bourke, D L

    1999-11-01

    The percentage of penetrating eye injuries in war has increased significantly in this century compared with the total number of combat injuries. With the increasing use of fragmentation weapons and possibly laser weapons on the battle-field in the future, the rate of eye injuries may exceed the 13% of the total military injuries found in Operations Desert Storm/Shield. During the Iran-Iraq War (1980-1988), eye injuries revealed that retained foreign bodies and posterior segment injuries have an improved prognosis in future military ophthalmic surgery as a result of modern diagnostic and treatment modalities. Compared with the increasing penetrating eye injuries on the battlefield, advances in ophthalmic surgery are insignificant. Eye armor, such as visors that flip up and down and protect the eyes from laser injury, needs to be developed. Similar eye protection is being developed in civilian sportswear. Penetrating eye injury in the civilian sector is becoming much closer to the military model and is now comparable for several reasons. PMID:10578588

  7. The mechanism of penetration increase in A-TIG welding

    NASA Astrophysics Data System (ADS)

    Zhang, Rui-Hua; Pan, Ji-Luan; Katayama, Seiji

    2011-06-01

    The mechanism of the increasing of A-TIG welding penetration is studied by using the activating flux we developed for stainless steel. The effect of flux on the flow and temperature fields of weld pool is simulated by the PHOENICS software. It shows that without flux, the fluid flow will be outward along the surface of the weld pool and then down, resulting in a flatter weld pool shape. With the flux, the oxygen, which changes the temperature dependence of surface tension grads from a negative value to a positive value, can cause significant changes on the weld penetration. Fluid flow will be inward along the surface of the weld pool toward the center and then down. This fluid flow pattern efficiently transfers heat to the weld root and produces a relatively deep and narrow weld. This change is the main cause of penetration increase. Moreover, arc construction can cause the weld width to become narrower and the penetration to become deeper, but this is not the main cause of penetration increase. The effects of flux on fluid flow of the weld pool surface and arc profiles were observed in conventional TIG welding and in A-TIG welding by using high-speed video camera. The fluid flow behavior was visualized in realtime scale by micro focused X-ray transmission video observation system. The result indicated that stronger inward fluid flow patterns leading to weld beads with narrower width and deeper penetration could be apparently identified in the case of A-TIG welding. The flux could change the direction of fluid flow in welding pool. It has a good agreement with the simulation results.

  8. Network Penetration Testing and Research

    NASA Technical Reports Server (NTRS)

    Murphy, Brandon F.

    2013-01-01

    This paper will focus the on research and testing done on penetrating a network for security purposes. This research will provide the IT security office new methods of attacks across and against a company's network as well as introduce them to new platforms and software that can be used to better assist with protecting against such attacks. Throughout this paper testing and research has been done on two different Linux based operating systems, for attacking and compromising a Windows based host computer. Backtrack 5 and BlackBuntu (Linux based penetration testing operating systems) are two different "attacker'' computers that will attempt to plant viruses and or NASA USRP - Internship Final Report exploits on a host Windows 7 operating system, as well as try to retrieve information from the host. On each Linux OS (Backtrack 5 and BlackBuntu) there is penetration testing software which provides the necessary tools to create exploits that can compromise a windows system as well as other operating systems. This paper will focus on two main methods of deploying exploits 1 onto a host computer in order to retrieve information from a compromised system. One method of deployment for an exploit that was tested is known as a "social engineering" exploit. This type of method requires interaction from unsuspecting user. With this user interaction, a deployed exploit may allow a malicious user to gain access to the unsuspecting user's computer as well as the network that such computer is connected to. Due to more advance security setting and antivirus protection and detection, this method is easily identified and defended against. The second method of exploit deployment is the method mainly focused upon within this paper. This method required extensive research on the best way to compromise a security enabled protected network. Once a network has been compromised, then any and all devices connected to such network has the potential to be compromised as well. With a compromised

  9. Tokamak coordinate conventions: COCOS

    NASA Astrophysics Data System (ADS)

    Sauter, O.; Medvedev, S. Yu.

    2013-02-01

    Dealing with electromagnetic fields, in particular current and related magnetic fields, yields "natural" physical vector relations in 3-D. However, when it comes to choosing local coordinate systems, the "usual" right-handed systems are not necessarily the best choices, which means that there are several options being chosen. In the magnetic fusion community such a difficulty exists for the choices of the cylindrical and of the toroidal coordinate systems. In addition many codes depend on knowledge of an equilibrium. In particular, the Grad-Shafranov axisymmetric equilibrium solution for tokamak plasmas, ψ, does not depend on the sign of the plasma current Ip nor that of the magnetic field B0. This often results in ill-defined conventions. Moreover the sign, amplitude and offset of ψ are of less importance, since the free sources in the equation depend on the normalized radial coordinate. The signs of the free sources, dp/dψ and dF2/dψ (p being the pressure, ψ the poloidal magnetic flux and F=RBφ), must be consistent to generate the current density profile. For example, RF and CD calculations (Radio Frequency heating and Current Drive) require an exact sign convention in order to calculate a co- or counter-CD component. It is shown that there are over 16 different coordinate conventions. This paper proposes a unique identifier, the COCOS convention, to distinguish between the 16 most-commonly used options. Given the present worldwide efforts towards code integration, the proposed new index COCOS defining uniquely the COordinate COnventionS required as input by a given code or module is particularly useful. As codes use different conventions, it is useful to allow different sign conventions for equilibrium code input and output, equilibrium being at the core of any calculations in magnetic fusion. Additionally, given two different COCOS conventions, it becomes simple to transform between them. The relevant transformations are described in detail.

  10. Conventional terrorism and critical care.

    PubMed

    Singer, Pierre; Cohen, Jonathan D; Stein, Michael

    2005-01-01

    Incidents of conventional weapons terror are increasingly part of the reality of the modern world, and in Israel, 19,948 incidents have been reported from September 2000 to December 2003. Most victims are injured in explosions resulting from suicide bombings. Exposure to the blast (primary mechanism of injury) may produce unique injuries affecting gas-containing organs, including perforation of the eardrums (most common injury); pulmonary blast injury, characterized by alveolar capillary disruption and bronchopleural fistulas; and bowel perforation, which is uncommon and may be delayed from 1 to 14 days after the injury. However, most injuries are the result of penetrating trauma (secondary mechanism) resulting from bomb fragments and nails, bolts, and steel pellets embedded in the bomb striking the victim, and blunt trauma (tertiary mechanism) sustained when the victim is propelled against an object by the blast wind. The severity of the injuries is increased when the blast occurs in a confined space. Victims of terror-inflicted injuries have a high Injury Severity Score (30% >16), a high requirement for intensive care unit admission (22.8% in Israel), and have a more prolonged hospital course and higher mortality than victims of any other form of trauma. PMID:15640681

  11. Field measurement of penetrator seismic coupling in sediments and volcanic rocks

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Latham, G. V.; Frohlich, C.

    1979-01-01

    Field experiments were conducted to determine experimentally how well a seismometer installed using a penetrator would be coupled to the ground. A dry lake bed and a lava bed were chosen as test sites to represent geological environments of two widely different material properties. At each site, two half-scale penetrators were fired into the ground, a three-component geophone assembly was mounted to the aft end of each penetrator, and dummy penetrators were fired at various distances to generate seismic signals. The recorded signals were digitized, and cross-spectral analyses were performed to compare the observed signals in terms of power spectral density ratio, coherence and phase difference. The analyses indicate that seismometers deployed by penetrators will be as well coupled to the ground as are seismometers installed by conventional methods for the frequency range of interest in earthquake seismology, although some minor differences were observed at frequencies near the upper limit of the frequency band.

  12. Quality Assessment of Longissimus and Semitendinosus Muscles from Beef Cattle Subjected to Non-penetrative and Penetrative Percussive Stunning Methods

    PubMed Central

    Sazili, A. Q.; Norbaiyah, B.; Zulkifli, I.; Goh, Y. M.; Lotfi, M.; Small, A. H.

    2013-01-01

    This study provides a comparative analysis of the effects of pre-slaughter penetrative and non-penetrative stunning and post-slaughter stunning on meat quality attributes in longissimus lumborum (LL) and semitendinosus (ST) muscles in heifers. Ten animals were assigned to each of four treatment groups: i) animals were subjected to conventional Halal slaughter (a clean incision through the structures at the front of the upper neck - the trachea, oesophagus, carotid arteries and jugular veins) and post-cut penetrating mechanical stun within 10 to 20 s of the neck cut (Unstunned; US); ii) high power non-penetrating mechanical stunning followed by the neck cut (HPNP); iii) low power non-penetrating mechanical stunning followed by the neck cut (LPNP); and iv) penetrative stunning using a captive bolt pistol followed by the neck cut (P). For each carcass, muscle samples were removed within 45 min of slaughter, portioned and analysed for pH, cooking loss, water holding capacity (WHC), tenderness (WBS), lipid oxidation (TBARS) and color, over a two week storage period. Stunning did not affect pH and cooking loss. Significant differences in water holding capacity, tenderness, lipid oxidation and color were present at different storage time points. HPNP stunning resulted in lower WHC and color values, particularly lightness (L*), higher TBARS values and peak force values compared with those stunned using LPNP, P and US. These adverse effects on quality were mostly encountered in the ST muscle. In conclusion, the meat quality achieved using P, LPNP and US treatments was comparable, and no treatment stood out as considerably better than another. PMID:25049845

  13. A Quiet Convention.

    ERIC Educational Resources Information Center

    Suggs, Welch

    2003-01-01

    Describes how discussion of governance and academic standards dominated the proceedings at the first NCAA convention of Myles Brand's presidency. The new president also offered a qualified endorsement of Title IX. (EV)

  14. Cincinnati; Our Convention City

    ERIC Educational Resources Information Center

    Borchin, Anna

    1970-01-01

    During Easter week, 1971, Cincinnati will be the hostess of the 50th anniversary convention of the Catholic Library Association. Items of historical interest concerning the city are briefly described. (NH)

  15. Synthesis and processing of composites by reactive metal penetration

    SciTech Connect

    Loehman, R.E.; Ewsuk, K.G.; Tomsia, A.P.

    1995-05-01

    Ceramic-metal composites are being developed because their high stiffness-to weight ratios, good fracture toughness, and variable electrical and thermal properties give them advantages over more conventional materials. However, because ceramic-metal composite components presently are more expensive than monolithic materials, improvements in processing are required to reduce manufacturing costs. Reactive metal penetration is a promising new method for making ceramic- and metal-matrix composites that has the advantage of being inherently a net-shape process. This technique, once fully developed, will provide another capability for manufacturing the advanced ceramic composites that are needed for many light-weight structural and wear applications. The lower densities of these composites lead directly to energy savings in use. Near-net-shape fabrication of composite parts should lead to additional savings because costly and energy intensive grinding and machining operations are significantly reduced, and the waste generated from such finishing operations is minimized. The goals of this research program are: (1) to identify feasible compositional systems for making composites by reactive metal penetration; (2) to understand the mechanism(s) of composite formation by reactive metal penetration; and (3) to learn how to control and optimize reactive metal penetration for economical production of composites and composite coatings.

  16. Intense X-ray machine for penetrating radiography

    NASA Astrophysics Data System (ADS)

    Lucht, Roy A.; Eckhouse, Shimon

    Penetrating radiography has been used for many years in the nuclear weapons research programs. Infrequently penetrating radiography has been used in conventional weapons research programs. For example the Los Alamos PHERMEX machine was used to view uranium rods penetrating steel for the GAU-8 program, and the Ector machine was used to see low density regions in forming metal jets. The armor/anti-armor program at Los Alamos has created a need for an intense flash X-ray machine that can be dedicated to conventional weapons research. The Balanced Technology Initiative, through DARPA, has funded the design and construction of such a machine at Los Alamos. It will be an 8- to 10-MeV diode machine capable of delivering a dose of 500 R at 1 m with a spot size of less than 5 mm. The machine used an 87.5-stage low inductance Marx generator that charges up a 7.4-(Omega), 32-ns water line. The water line is discharged through a self-breakdown oil switch into a 12.4-(Omega) water line that rings up the voltage into the high impendance X-ray diode. A long (233-cm) vacuum drift tube is used to separate the large diameter oil-insulated diode region from the X-ray source area that may be exposed to high overpressures by the explosive experiments. The electron beam is selffocused at the target area using a low pressure background gas.

  17. Management of penetrating brain injury

    PubMed Central

    Kazim, Syed Faraz; Shamim, Muhammad Shahzad; Tahir, Muhammad Zubair; Enam, Syed Ather; Waheed, Shahan

    2011-01-01

    Penetrating brain injury (PBI), though less prevalent than closed head trauma, carries a worse prognosis. The publication of Guidelines for the Management of Penetrating Brain Injury in 2001, attempted to standardize the management of PBI. This paper provides a precise and updated account of the medical and surgical management of these unique injuries which still present a significant challenge to practicing neurosurgeons worldwide. The management algorithms presented in this document are based on Guidelines for the Management of Penetrating Brain Injury and the recommendations are from literature published after 2001. Optimum management of PBI requires adequate comprehension of mechanism and pathophysiology of injury. Based on current evidence, we recommend computed tomography scanning as the neuroradiologic modality of choice for PBI patients. Cerebral angiography is recommended in patients with PBI, where there is a high suspicion of vascular injury. It is still debatable whether craniectomy or craniotomy is the best approach in PBI patients. The recent trend is toward a less aggressive debridement of deep-seated bone and missile fragments and a more aggressive antibiotic prophylaxis in an effort to improve outcomes. Cerebrospinal fluid (CSF) leaks are common in PBI patients and surgical correction is recommended for those which do not close spontaneously or are refractory to CSF diversion through a ventricular or lumbar drain. The risk of post-traumatic epilepsy after PBI is high, and therefore, the use of prophylactic anticonvulsants is recommended. Advanced age, suicide attempts, associated coagulopathy, Glasgow coma scale score of 3 with bilaterally fixed and dilated pupils, and high initial intracranial pressure have been correlated with worse outcomes in PBI patients. PMID:21887033

  18. Jet penetration of high explosive

    SciTech Connect

    Poulsen, P

    1999-08-11

    It is found that a transition between two flow patterns takes place in thick HE targets. In this case, the jet will initially propagate into the HE at the same rate as into an inert material of the same density. The part of the jet that has stagnated and is flowing nearly co-axially with the incoming jet (but at a much lower speed) is being forced toward the surface of the incoming jet by the pressure of the reaction products but has not as yet made contact. After it makes contact, both axial and perpendicular momentum transfer takes place between the two jet components. After this transition, a new steady state will develop for the propagating jet, with the unperturbed front of the jet propagating at a slower rate than previously. The perturbed front of the jet is still propagating at or near the original rate, having had relatively little axial momentum exchange. However, it has acquired radial momentum and is spreading out as it is propagating; it is therefore becoming less capable of penetrating downstream targets. It is the unperturbed part of the jet that is capable of penetrating downstream targets. A calculational method for predicting this case is presented in this report.

  19. Convention Problems - 1787.

    ERIC Educational Resources Information Center

    Hanson, Deroy L.

    Designed to motivate eighth-grade civics students in the study of the United States Constitution, this game is intended to simulate the basic problems faced by the delegates to the Philadelphia Convention of 1787. The four parts of the game introduce the governmental concepts of the bicameral legislature, the executive branch, the judicial branch,…

  20. Cable Braid Electromagnetic Penetration Model.

    SciTech Connect

    Warne, Larry K.; Langston, William L.; Basilio, Lorena I.; Johnson, W. A.

    2015-06-01

    The model for penetration of a wire braid is rigorously formulated. Integral formulas are developed from energy principles and reciprocity for both self and transfer immittances in terms of potentials for the fields. The detailed boundary value problem for the wire braid is also setup in a very efficient manner; the braid wires act as sources for the potentials in the form of a sequence of line multipoles with unknown coefficients that are determined by means of conditions arising from the wire surface boundary conditions. Approximations are introduced to relate the local properties of the braid wires to a simplified infinite periodic planar geometry. This is used in a simplified application of reciprocity to be able to treat nonuniform coaxial geometries including eccentric interior coaxial arrangements and an exterior ground plane.

  1. Tissue Penetration of Antifungal Agents

    PubMed Central

    Felton, Timothy; Troke, Peter F.

    2014-01-01

    SUMMARY Understanding the tissue penetration of systemically administered antifungal agents is critical for a proper appreciation of their antifungal efficacy in animals and humans. Both the time course of an antifungal drug and its absolute concentrations within tissues may differ significantly from those observed in the bloodstream. In addition, tissue concentrations must also be interpreted within the context of the pathogenesis of the various invasive fungal infections, which differ significantly. There are major technical obstacles to the estimation of concentrations of antifungal agents in various tissue subcompartments, yet these agents, even those within the same class, may exhibit markedly different tissue distributions. This review explores these issues and provides a summary of tissue concentrations of 11 currently licensed systemic antifungal agents. It also explores the therapeutic implications of their distribution at various sites of infection. PMID:24396137

  2. A lightweight ground penetrating radar

    SciTech Connect

    Koppenjan, S.K.; Allen, C.M.; Gardner, D.; Wong, H.R.

    1998-12-31

    The detection of buried objects, particularly unexploded ordnance (UXO), has gained significant interest in the US in the late 1990s. The desire to remediate the thousands of sites worldwide has become an increasing humanitarian concern. The application of radar to this problem has received renewed attention. Bechtel Nevada, Special Technologies Laboratory (STL) has developed several frequency modulated, continuous wave (FM-CW) ground penetrating radar (GPR) units for the US Department of Energy since 1984. To meet these new technical requirements for high resolution data and UXO detection, STL is moving forward with advances to GPR technology, signal processing, and imaging with the development of an innovative system. The goal is to design and fabricate a lightweight, battery operated unit that does not require surface contact and can be operated by a novice user.

  3. Bodily action penetrates affective perception

    PubMed Central

    Rigutti, Sara; Gerbino, Walter

    2016-01-01

    Fantoni & Gerbino (2014) showed that subtle postural shifts associated with reaching can have a strong hedonic impact and affect how actors experience facial expressions of emotion. Using a novel Motor Action Mood Induction Procedure (MAMIP), they found consistent congruency effects in participants who performed a facial emotion identification task after a sequence of visually-guided reaches: a face perceived as neutral in a baseline condition appeared slightly happy after comfortable actions and slightly angry after uncomfortable actions. However, skeptics about the penetrability of perception (Zeimbekis & Raftopoulos, 2015) would consider such evidence insufficient to demonstrate that observer’s internal states induced by action comfort/discomfort affect perception in a top-down fashion. The action-modulated mood might have produced a back-end memory effect capable of affecting post-perceptual and decision processing, but not front-end perception. Here, we present evidence that performing a facial emotion detection (not identification) task after MAMIP exhibits systematic mood-congruent sensitivity changes, rather than response bias changes attributable to cognitive set shifts; i.e., we show that observer’s internal states induced by bodily action can modulate affective perception. The detection threshold for happiness was lower after fifty comfortable than uncomfortable reaches; while the detection threshold for anger was lower after fifty uncomfortable than comfortable reaches. Action valence induced an overall sensitivity improvement in detecting subtle variations of congruent facial expressions (happiness after positive comfortable actions, anger after negative uncomfortable actions), in the absence of significant response bias shifts. Notably, both comfortable and uncomfortable reaches impact sensitivity in an approximately symmetric way relative to a baseline inaction condition. All of these constitute compelling evidence of a genuine top-down effect on

  4. GSTAMIDS ground-penetrating radar: hardware description

    NASA Astrophysics Data System (ADS)

    Sower, Gary D.; Eberly, John; Christy, Ed

    2001-10-01

    The Ground Standoff Mine Detection System (GSTAMIDS) is now in the Engineering, Manufacturing and Development (EMD) Block 0 phase for USA CECOM. The Mine Detection Subsystem (MDS) presently utilizes three different sensor technologies to detect buried anti-tank (AT) land mines; Ground Penetrating Radar (GPR), Pulsed Magnetic Induction (PMI), and passive infrared (IR). The GSTAMIDS hardware and software architectures are designed so that other technologies can readily be incorporated when and if they prove viable. Each sensor suite is designed to detect the buried mines and to discriminate against various clutter and background objects. Sensor data fusion of the outputs of the individual sensor suites then enhances the detection probability while reducing the false alarm rate from clutter objects. The metal detector is an essential tool for buried mine detection, as metal land mines still account for a large percentage of land mines. Technologies such as nuclear quadrupole resonance (NQR or QR) are presently being developed to detect or confirm the presence of explosive material in buried land mines, particularly the so-called plastic mines; unfortunately, the radio frequency signals required cannot penetrate into a metal land mine. The limitation of the metal detector is not in detection of the metal mines, but in the additional detection of metal clutter. A metal detector has been developed using singular value decomposition (SVD) extraction techniques to discriminate the mines from the clutter, thereby greatly reducing false alarm rates. This mine detector is designed to characterize the impulse response function of the metal objects, based on a parametric three-pole model of the response, and to use pattern recognition to determine the match of the responses to known mines. In addition to discrimination against clutter, the system can also generally tell one mine type from another. This paper describes the PMI sensor suite hardware and its physical incorporation

  5. A rheological mechanism of penetrative wear

    NASA Technical Reports Server (NTRS)

    Bates, T. R., Jr.; Ludema, K. C.; Brainard, W. A.

    1974-01-01

    A model is proposed which explains the penetrative wear of a soft material by a harder one. Three distinct modes of penetration are present depending on the applied load. During the most severe penetration plate-like wear debris is ejected at the leading edge of the slider. A series of slip line fields is presented to approximate this debris formation process. Plastic constraint is seen to be an important factor in wear particle formation.

  6. In-place HEPA filter penetration test

    SciTech Connect

    Bergman, W.; Wilson, K.; Elliott, J.

    1997-08-01

    We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in-place penetration test is practical. 14 refs., 14 figs., 3 tabs.

  7. Manual and automatic flight control during severe turbulence penetration

    NASA Technical Reports Server (NTRS)

    Johnston, D. E.; Klein, R. H.; Hoh, R. H.

    1976-01-01

    An analytical and experimental investigation of possible contributing factors in jet aircraft turbulence upsets was conducted. Major contributing factors identified included autopilot and display deficiencies, the large aircraft inertia and associated long response time, and excessive pilot workload. An integrated flight and thrust energy management director system was synthesized. The system was incorporated in a moving-base simulation and evaluated using highly experienced airline pilots. The evaluation included comparison of pilot workload and flight performance during severe turbulence penetration utilizing four control/display concepts: manual control with conventional full panel display, conventional autopilot (A/P-A) with conventional full panel display, improved autopilot (A/P-B) with conventional full panel display plus thrust director display, and longitudinal flight director with conventional full panel display plus thrust director display. Simulation results show improved performance, reduced pilot workload, and a pilot preference for the autopilot system controlling to the flight director command and manual control of thrust following the trim thrust director.

  8. Indications for Corneal Transplantation at a Tertiary Referral Center in Tehran

    PubMed Central

    Zare, Mohammad; Javadi, Mohammad-Ali; Einollahi, Bahram; Baradaran-Rafii, Alireza; Ghanavati, Siamak Zarei; Farsani, Mohammad-Reza Jamshidi; Mohammadi, Parviz; Feizi, Sepehr

    2010-01-01

    Purpose To report the indications and techniques of corneal transplantation at a tertiary referral center in Tehran over a 3-year period. Methods Records of patients who had undergone any kind of corneal transplantation at Labbafinejad Medical Center, Tehran, Iran from March 2004 to March 2007 were reviewed to determine the indications and types of corneal transplantation. Results During this period, 776 eyes of 756 patients (including 504 male subjects) with mean age of 41.3±21.3 years underwent corneal transplantation. The most common indication was keratoconus (n=317, 40.8%) followed by bullous keratopathy (n=90, 11.6%), non-herpetic corneal scars (n=62, 8.0%), infectious corneal ulcers (n=61, 7.9%), previously failed grafts (n=61, 7.9%), endothelial and stromal corneal dystrophies (n=28, 3.6%), and trachoma keratopathy (n=26, 3.3%). Other indications including Terrien’s marginal degeneration, post-LASIK keratectasia, trauma, chemical burns, and peripheral ulcerative keratitis constituted the rest of cases. Techniques of corneal transplantation included penetrating keratoplasty (n=607, 78.2%), deep anterior lamellar keratoplasty (n=108, 13.9%), conventional lamellar keratoplasty (n=44, 5.7%), automated lamellar therapeutic keratoplasty (n=8, 1.0%), and Descemet stripping endothelial keratoplasty (n=6, 0.8%) in descending order. The remaining cases were endothelial keratoplasty and sclerokeratoplasty. Conclusion In this study, keratoconus was the most common indication for penetrating keratoplasty which was the most prevalent technique of corneal transplantation. However, deep anterior lamellar keratoplasty is emerging as a growing alternative for corneal pathologies not involving the endothelium. PMID:22737335

  9. Ground Penetrating Radar in Hydrogeophysics

    SciTech Connect

    Hubbard, Susan; Lambot, S.; Binley, A.; Slob, E.; Hubbard, S.

    2008-01-15

    To meet the needs of a growing population and to provide us with a higher quality of life, increasing pressures are being placed on our environment through the development of agriculture, industry, and infrastructures. Soil erosion, groundwater depletion, salinization, and pollution have been recognized for decades as major threats to ecosystems and human health. More recently, the progressive substitution of fossil fuels by biofuels for energy production and climate change have been recognized as potential threats to our water resources and sustained agricultural productivity. The vadose zone mediates many of the processes that govern water resources and quality, such as the partition of precipitation into infiltration and runoff , groundwater recharge, contaminant transport, plant growth, evaporation, and energy exchanges between the Earth's surface and its atmosphere. It also determines soil organic carbon sequestration and carbon-cycle feedbacks, which could substantially impact climate change. The vadose zone's inherent spatial variability and inaccessibility precludes direct observation of the important subsurface processes. In a societal context where the development of sustainable and optimal environmental management strategies has become a priority, there is a strong prerequisite for the development of noninvasive characterization and monitoring techniques of the vadose zone. In particular, hydrogeophysical approaches applied at relevant scales are required to appraise dynamic subsurface phenomena and to develop optimal sustainability, exploitation, and remediation strategies. Among existing geophysical techniques, ground penetrating radar (GPR) technology is of particular interest for providing high-resolution subsurface images and specifically addressing water-related questions. Ground penetrating radar is based on the transmission and reception of VHF-UHF (30-3000 MHz) electromagnetic waves into the ground, whose propagation is determined by the soil

  10. Ultrasonic/Sonic Impacting Penetrators

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Chang, Zensheu; Sherrit, Stewart; Stark, Randall A.

    2008-01-01

    Ultrasonic/sonic impacting penetrators (USIPs) are recent additions to the series of apparatuses based on ultrasonic/sonic drill corers (USDCs). A USIP enables a rod probe to penetrate packed soil or another substance of similar consistency, without need to apply a large axial force that could result in buckling of the probe or in damage to some buried objects. USIPs were conceived for use in probing and analyzing soil to depths of tens of centimeters in the vicinity of buried barrels containing toxic waste, without causing rupture of the barrels. USIPs could also be used for other purposes, including, for example, searching for pipes, barrels, or other hard objects buried in soil; and detecting land mines. USDCs and other apparatuses based on USDCs have been described in numerous previous NASA Tech Briefs articles. The ones reported previously were designed, variously, for boring into, and/or acquiring samples of, rock or other hard, brittle materials of geological interest. To recapitulate: A USDC can be characterized as a lightweight, low-power, piezoelectrically driven jackhammer in which ultrasonic and sonic vibrations are generated and coupled to a tool bit. As shown in the figure, a basic USDC includes a piezoelectric stack, a backing and a horn connected to the stack, a free mass (free in the sense that it can slide axially a short distance between the horn and the shoulder of tool bit), and a tool bit, i.e., probe for USIP. The piezoelectric stack is driven at the resonance frequency of the stack/horn/backing assembly to create ultrasonic vibrations that are mechanically amplified by the horn. To prevent fracture during operation, the piezoelectric stack is held in compression by a bolt. The bouncing of the free mass between the horn and the tool bit at sonic frequencies generates hammering actions to the bit that are more effective for drilling than is the microhammering action of ultrasonic vibrations in ordinary ultrasonic drills. The hammering actions

  11. Field Measurements of Penetrator Seismic Coupling in Sediments and Volcanic Rocks

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Latham, G. V.; Frohlich, C.; Blanchard, M. B.; Murphy, J. P.

    1979-01-01

    Field experiments were conducted to determine how well a seismometer installed using a penetrator would be coupled to the ground. A dry-lake bed and a lava bed were chosen as test sites to represent geological environments of two widely different material properties. At each site, two half-scale penetrators were fired into the ground, a three-component geophone assembly was mounted to the aft end of each penetrator, and dummy penetrators were at various distances to generate seismic signals. These signals were detected by the penetrator-mounted geophone assembly and by a reference geophone assembly buried or anchored to surface rock and 1-m from the penetrator. The recorded signals were digitized, and cross-spectral analyses were performed to compare the observed signals in terms of power spectral density ratio, coherence, and phase difference. The analyses indicate that seismometers deployed by penetrators will be as well coupled to the ground as are seismometers installed by conventional methods for the frequency range of interest in earthquake seismology.

  12. Instability of a penetrating blade

    NASA Astrophysics Data System (ADS)

    Bigoni, D.; Bosi, F.; Dal Corso, F.; Misseroni, D.

    2014-03-01

    Application of a dead compressive load at the free end of an elastic rod (the ‘blade') induces its penetration into a sliding sleeve ending with a linear elastic spring. Bifurcation and stability analysis of this simple elastic system shows a variety of unexpected behaviors: (i) an increase of buckling load at decreasing of elastic stiffness; (ii) a finite number of buckling loads for a system with infinite degrees of freedom (leading to a non-standard Sturm-Liouville problem); (iii) more than one bifurcation load associated to each bifurcation mode; (iv) a restabilization of the straight configuration after the second bifurcation load associated to the first instability mode; (v) the presence of an Eshelby-like (or configurational) force, deeply influencing stability. Only the first of these behaviors was previously known, the second and third ones disprove common beliefs, the fourth highlights a sort of ‘island of instability', and the last one shows surprising phenomena and effects on stability.

  13. Foliage penetrating radar imaging system

    NASA Astrophysics Data System (ADS)

    Beaudoin, Christopher J.; Gatesman, Andrew J.; Giles, Robert H.; Waldman, Jerry; Testorf, Markus E.; Fiddy, Michael A.; Nixon, William E.

    2002-12-01

    A far-field radar range has been constructed at the University of Massachusetts Lowell Submillimeter-Wave Technology Laboratory to investigate electromagnetic scattering and imagery of threat military targets located in forested terrain. The radar system, operating at X-band, uses 1/35th scale targets and scenes to acquire VHF/UHF signature data. The trees and ground planes included in the measurement scenes have been dielectrically scaled in order to properly model the target/clutter interaction. The signature libraries acquired by the system could be used to help develop automatic target recognition algorithms. The difficulty in target recognition in forested areas is due to the fact that trees can have a signature larger than that of the target. The rather long wavelengths required to penetrate the foliage canopy also complicate target recognition by limiting image resolution. The measurement system and imaging algorithm will be presented as well as a validation of the measurements obtained by comparing measured signatures with analytical predictions. Preliminary linear co-polarization (HH,VV) and cross-polarization (HV,VH) data will be presented on an M1 tank in both forested and open-field scenarios.

  14. Stepped frequency ground penetrating radar

    DOEpatents

    Vadnais, Kenneth G.; Bashforth, Michael B.; Lewallen, Tricia S.; Nammath, Sharyn R.

    1994-01-01

    A stepped frequency ground penetrating radar system is described comprising an RF signal generating section capable of producing stepped frequency signals in spaced and equal increments of time and frequency over a preselected bandwidth which serves as a common RF signal source for both a transmit portion and a receive portion of the system. In the transmit portion of the system the signal is processed into in-phase and quadrature signals which are then amplified and then transmitted toward a target. The reflected signals from the target are then received by a receive antenna and mixed with a reference signal from the common RF signal source in a mixer whose output is then fed through a low pass filter. The DC output, after amplification and demodulation, is digitized and converted into a frequency domain signal by a Fast Fourier Transform. A plot of the frequency domain signals from all of the stepped frequencies broadcast toward and received from the target yields information concerning the range (distance) and cross section (size) of the target.

  15. Penetrating Wounds of Great Vessels

    PubMed Central

    Symbas, P. N.; Kourias, E.; Tyras, D. H.; Hatcher, C. R.

    1974-01-01

    Thirty-six patients with penetrating wounds of the great vessels treated at Grady Memorial Hospital during a 7-year period were reviewed. In more than 50% of the cases, diagnosis of the injury was made at the time of emergency thoracotomy for massive bleeding. In the remaining patients the diagnosis was suspected: 1) when the pulse distal to the vascular injury was absent or weak; 2) when the patient had symptoms and signs of impaired central nervous system perfusion; 3) when the missile had traversed the mediastinum and there was roentgenographic evidence of widening of the mediastinal shadow; or, 4) when a new murmur appeared. In all suspected cases with great vessel injury, the diagnosis was confirmed arteriographically. Arteriography in such patients should be performed to define the type and site of vascular injury so that its repair can be properly planned. Twenty-nine patients recovered from their injury, 6 succumbed as a result of it and 1 required midforearm amputation following repair of a subclavian artery and vein injury. Most of these patients underwent autotransfusion which greatly contributed to their successful outcome. Local temporary shunt was used for protection of the spinal cord and/or brain when impairment of their perfusion was required for the repair of the vascular wounds. ImagesFig. 1.Fig. 3.Fig. 4. PMID:17859862

  16. Transnasal, intracranial penetrating injury treated endoscopically.

    PubMed

    Cetinkaya, Erdem Atalay; Okan, Cinemre; Pelin, Kesapli

    2006-04-01

    Intracranial penetrating injury through the nose is uncommon. We present the case of a four-year-old girl who sustained a transnasal, intracranial penetrating injury with a sharp wooden object. We performed endoscopic removal of the foreign body and repair of the associated cerebrospinal fluid fistula. PMID:16623978

  17. Social Penetration: A Description, Research, and Evaluation.

    ERIC Educational Resources Information Center

    Allensworth, Nicole J.

    Social penetration has been described by S.W. Littlejohn (1992) as "the process of increasing disclosure and intimacy in a relationship." The phrase "social penetration" originated with I. Altman and D. Taylor, the foremost researchers in this area. From other theories, Altman and Taylor developed a unified theory which provided a stable base from…

  18. FRACTIONAL PENETRATION OF PAINT OVERSPRAY ARRESTORS

    EPA Science Inventory

    The report describes the development of fractional penetration curves for liquid droplet penetration of overspray arrestors for discrete droplet diameters from 0.3 to 10 micrometers. (NOTE: Fine particulates are particles with diameters of 10 micrometers or less.) These data poin...

  19. Fluorescent penetration enhancers for transdermal applications.

    PubMed

    Seto, Jennifer E; Polat, Baris E; VanVeller, Brett; Lopez, Renata F V; Langer, Robert; Blankschtein, Daniel

    2012-02-28

    Chemical penetration enhancers are often used to enhance transdermal drug delivery. However, the fundamental mechanisms that govern the interactions between penetration enhancers and skin are not fully understood. Therefore, the goal of this work was to identify naturally fluorescent penetration enhancers (FPEs) in order to utilize well-established fluorescence techniques to directly study the behavior of FPEs within skin. In this study, 12 fluorescent molecules with amphiphilic characteristics were evaluated as skin penetration enhancers. Eight of the molecules exhibited significant activity as skin penetration enhancers, determined using skin current enhancement ratios. In addition, to illustrate the novel, direct, and non-invasive visualization of the behavior of FPEs within skin, three case studies involving the use of two-photon fluorescence microscopy (TPM) are presented, including visualizing glycerol-mitigated and ultrasound-enhanced FPE skin penetration. Previous TPM studies have indirectly visualized the effect of penetration enhancers on the skin by using a fluorescent dye to probe the transdermal pathways of the enhancer. These effects can now be directly visualized and investigated using FPEs. Finally, future studies are proposed for generating FPE design principles. The combination of FPEs with fluorescence techniques represents a useful novel approach for obtaining physical insights on the behavior of penetration enhancers within the skin. PMID:22062691

  20. USDC based rapid penetrator of packed soil

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Chang, Zensheu; Sherrit, Stewart; Badescu, Mircea

    2006-01-01

    Environment protection requires more testing and analysis tools. To detect buried chemical containers or other objects embedded in soil and avoid possible damages of them, a penetrator of packed soil operated using low pushing force was developed. The design was based on a novel driving mechanism of the ultrasonic/sonic driller/corer (USDC) device developed in the NDEAA lab at JPL [Bar-Cohen et al 2001, Bao et al 2003]. In the penetrator, a small free-flying mass is energized by a piezoelectric transducer and impacts a rod probe on its shoulder at frequencies of hundreds times per second. The impacts help the probe to penetrate the packed soil rapidly. A great reduction of the needed pushing force for penetration was achieved. The details of the design of the prototype penetrator and the results of performance tests are presented.

  1. Conventional magnetic superconductors

    DOE PAGESBeta

    Wolowiec, C. T.; White, B. D.; Maple, M. B.

    2015-07-01

    We discuss several classes of conventional magnetic superconductors including the ternary rhodium borides and molybdenum chalcogenides (or Chevrel phases), and the quaternary nickel-borocarbides. These materials exhibit some exotic phenomena related to the interplay between superconductivity and long-range magnetic order including: the coexistence of superconductivity and antiferromagnetic order; reentrant and double reentrant superconductivity, magnetic field induced superconductivity, and the formation of a sinusoidally-modulated magnetic state that coexists with superconductivity. We introduce the article with a discussion of the binary and pseudobinary superconducting materials containing magnetic impurities which at best exhibit short-range “glassy” magnetic order. Early experiments on these materials led tomore » the idea of a magnetic exchange interaction between the localized spins of magnetic impurity ions and the spins of the conduction electrons which plays an important role in understanding conventional magnetic superconductors. Furthermore, these advances provide a natural foundation for investigating unconventional superconductivity in heavy-fermion compounds, cuprates, and other classes of materials in which superconductivity coexists with, or is in proximity to, a magnetically-ordered phase.« less

  2. Conventional magnetic superconductors

    SciTech Connect

    Wolowiec, C. T.; White, B. D.; Maple, M. B.

    2015-07-01

    We discuss several classes of conventional magnetic superconductors including the ternary rhodium borides and molybdenum chalcogenides (or Chevrel phases), and the quaternary nickel-borocarbides. These materials exhibit some exotic phenomena related to the interplay between superconductivity and long-range magnetic order including: the coexistence of superconductivity and antiferromagnetic order; reentrant and double reentrant superconductivity, magnetic field induced superconductivity, and the formation of a sinusoidally-modulated magnetic state that coexists with superconductivity. We introduce the article with a discussion of the binary and pseudobinary superconducting materials containing magnetic impurities which at best exhibit short-range “glassy” magnetic order. Early experiments on these materials led to the idea of a magnetic exchange interaction between the localized spins of magnetic impurity ions and the spins of the conduction electrons which plays an important role in understanding conventional magnetic superconductors. Furthermore, these advances provide a natural foundation for investigating unconventional superconductivity in heavy-fermion compounds, cuprates, and other classes of materials in which superconductivity coexists with, or is in proximity to, a magnetically-ordered phase.

  3. Biodiesel from conventional feedstocks.

    PubMed

    Du, Wei; Liu, De-Hua

    2012-01-01

    At present, traditional fossil fuels are used predominantly in China, presenting the country with challenges that include sustainable energy supply, energy efficiency improvement, and reduction of greenhouse gas emissions. In 2007, China issued The Strategic Plan of the Mid-and-Long Term Development of Renewable Energy, which aims to increase the share of clean energy in the country's energy consumption to 15% by 2020 from only 7.5% in 2005. Biodiesel, an important renewable fuel with significant advantages over fossil diesel, has attracted great attention in the USA and European countries. However, biodiesel is still in its infancy in China, although its future is promising. This chapter reviews biodiesel production from conventional feedstocks in the country, including feedstock supply and state of the art technologies for the transesterification reaction through which biodiesel is made, particularly the enzymatic catalytic process developed by Chinese scientists. Finally, the constraints and perspectives for China's biodiesel development are highlighted. PMID:22085921

  4. Conventional therapies for psoriasis.

    PubMed

    Rebora, A

    2007-01-01

    Conventional treatments of psoriasis include topical and systemic drugs. For sake of brevity, the presentation will deal only with systemic therapy. Three drugs are presently available in Italy: methotrexate, acitretin and cyclosporin A. Their efficacy is almost identical, all of them achieving PASI 75 in about 60% of cases in 12 weeks The indications (which, in Italy, do not include psoriasis for methotrexate), the contraindications, the interactions, the adverse effects and the precautions in their use will be discussed. Methotrexate side effects account for more than 10% of cases and include nausea and vomiting and chiefly increase of blood levels of liver enzymes. Acitretin side effects are numerous and varied, the most severe being increase of liver enzymes and blood lipids, renal impairment, and teratogenicity. Cyclosporin side effects are chiefly hypertension and renal failure. The Author concludes that cyclosporin is the drug with the best efficacy/side effect ratio, though it should be used in selected cases. PMID:17828351

  5. Eggshell penetration of various types of hens' eggs by Salmonella enterica serovar Enteritidis.

    PubMed

    Messens, Winy; Grijspeerdt, Koen; De Reu, Koen; De Ketelaere, Bart; Mertens, Kristof; Bamelis, Flip; Kemps, Bart; De Baerdemaeker, Josse; Decuypere, Eddy; Herman, Lieve

    2007-03-01

    Egg weight, shell thickness, number of pores, cuticle deposition, eggshell strength (dynamic stiffness and damping ratio), and the ability of Salmonella enterica serovar Enteritidis (SE) to penetrate the eggshell were determined. Penetration was assessed by filling the eggs with a selective medium that allowed viewing of Salmonella growth on the inside of the shell and membrane complex. After inoculation of each shell with on average 2.71 log CFU, the eggs were stored for up to 14 days at 20 degrees C and 60% relative humidity. Commercially available eggs were used. At 14 days of storage, only 6.0% of the eggs from free-range hens and 16.0% of the generic (i.e., eggs from hens in conventional battery cages that were given standard feed) white eggs were penetrated. The generic brown, organic, and omega-3-enriched eggs were penetrated at a frequency of 30 to 34%. In a second experiment it was shown that the layer strains of the hen (ISA-Brown Warren versus Bovans Goldline), which were kept in furnished cages, did not affect eggshell penetration by SE. For Bovans Goldline hens, the housing system (furnished cage versus aviary) did not affect penetration, while a trend was visible toward a higher fraction of penetrated eggshells when hens were fed corncob mix rather than standard feed. Eggshell penetration was observed more frequently in the absence of cuticle spots and for eggs having lower dynamic stiffness values. Shell contamination at the end of storage was highly correlated with SE penetration. PMID:17388050

  6. Modeling pollutant penetration across building envelopes

    SciTech Connect

    Liu, De-Ling; Nazaroff, William W.

    2001-04-01

    As air infiltrates through unintentional openings in building envelopes, pollutants may interact with adjacent surfaces. Such interactions can alter human exposure to air pollutants of outdoor origin. We present modeling explorations of the proportion of particles and reactive gases (e.g., ozone) that penetrate building envelopes as air enters through cracks and wall cavities. Calculations were performed for idealized rectangular cracks, assuming regular geometry, smooth inner crack surface and steady airflow. Particles of 0.1-1.0 {micro}m diameter are predicted to have the highest penetration efficiency, nearly unity for crack heights of 0.25 mm or larger, assuming a pressure difference of 4 Pa or greater and a flow path length of 3 cm or less. Supermicron and ultrafine particles are significantly removed by means of gravitational settling and Brownian diffusion, respectively. In addition to crack geometry, ozone penetration depends on its reactivity with crack surfaces, as parameterized by the reaction probability. For reaction probabilities less than {approx}10{sup -5}, penetration is complete for cracks heights greater than 1 mm. However, penetration through mm scale cracks is small if the reaction probability is {approx}10{sup -4} or greater. For wall cavities, fiberglass insulation is an efficient particle filter, but particles would penetrate efficiently through uninsulated wall cavities or through insulated cavities with significant airflow bypass. The ozone reaction probability on fiberglass fibers was measured to be 10{sup -7} for fibers previously exposed to high ozone levels and 6 x 10{sup -6} for unexposed fibers. Over this range, ozone penetration through fiberglass insulation would vary from >90% to {approx}10-40%. Thus, under many conditions penetration is high; however, there are realistic circumstances in which building envelopes can provide substantial pollutant removal. Not enough is yet known about the detailed nature of pollutant penetration

  7. Mechanisms of imiquimod skin penetration.

    PubMed

    Telò, Isabella; Pescina, Silvia; Padula, Cristina; Santi, Patrizia; Nicoli, Sara

    2016-09-10

    Imiquimod (IMQ) ia an immunostimulating drug used for the treatment of neoplastic skin diseases, such as actinic keratosis (AK) and superficial basal cell carcinoma (sBCC), and as adjuvant for vaccination. Imiquimod formulation and skin delivery is highly challenging because of its very low solubility in most pharmaceutical excipients and poor penetration properties. Objectives of the work were: (1) to evaluate IMQ solubility in different solvents and pharmaceutical excipients; (2) to evaluate IMQ skin retention after the application of simple saturated solutions; (3) to evaluate the role of stratum corneum and solvent uptake on IMQ skin retention and (4) to formulate IMQ in microemulsions - prepared using previously investigated components - and compare them with the commercial formulation. The results show that IMQ solubility is not related to the solubility parameter of the solvents considered. The highest solubility was found with oleic acid (74mg/ml); in the case of PEGs, the solubility increased linearly with MW (PEG 200: 1.9mg/ml; PEG 400 7.3mg/ml, PEG 600 12.8mg/ml). Imiquimod skin retention from saturated solutions (Tween 80, oleic acid, propylene glycol, PEG 200, PEG 400, PEG 600, Transcutol, 2-pyrrolidone, DMSO) resulted relatively similar, being 1.6μg/cm(2) in case of oleic acid (solubility 74mg/ml) and 0.18μg/cm(2) in case of propylene glycol (solubility 0.60mg/ml). Permeation experiments on stripped skin (no stratum corneum) and isolated dermis as well as uptake experiments on isolated stratum corneum sheets demonstrated that IMQ accumulation is related to skin solvent uptake. Finally, microemulsions (MEs) prepared with the above-studied components demonstrated a very good performance. In particular, a ME composed of 10% oleic acid, 35% Transcutol, 35% Tween 80 and 20% water is able to accumulate the same amount of drug as the commercial formulation but with far more efficiency, since its concentration was 12 times lower. PMID:27452419

  8. Earthquakes induced by deep penetrating bombing?

    NASA Astrophysics Data System (ADS)

    Balassanian, Serguei Y.

    2005-11-01

    The data of M≥5 earthquakes occurred in one year before and after 4 deep penetrating bombs in the region within 500 km and 1 000 km from the shooting site are presented. The 4 bombs are those happened in 1999 Kosovo of Yugoslavia, the 1991 Baghdad of Iraq, the 2001 Tora Bora of Afghanistan, and the 2003 Kirkuk of Iraq, respectively. The data indicate that the deep penetrating bombs may have remotely triggered some earthquakes. The deep penetrating bombs in seismically active regions should be forbidden.

  9. GNOME: an earth-penetrator code

    SciTech Connect

    Davie, N.T.; Richgels, M.A.

    1983-05-01

    The earth penetrator code GNOME is described, and its capabilities are illustrated by comparisons of computed results with actual field test data. GNOME uses decoupled approximate solution techniques to calculate the rigid body response of an earth penetrator. A modular structured programming method is employed, which allows a variety of pressure generating algorithms to be used without altering the basic program modules which consist of a time integrator and output routines. GNOME calculates axial and lateral loading on a cylindrical penetrator with an ogival or conical nose, but other geometrical shapes may be easily substituted for these by utilizing the modular program structure.

  10. Pressure enhanced penetration with shaped charge perforators

    DOEpatents

    Glenn, Lewis A.

    2001-01-01

    A downhole tool, adapted to retain a shaped charge surrounded by a superatmospherically pressurized light gas, is employed in a method for perforating a casing and penetrating reservoir rock around a wellbore. Penetration of a shaped charge jet can be enhanced by at least 40% by imploding a liner in the high pressure, light gas atmosphere. The gas pressure helps confine the jet on the axis of penetration in the latter stages of formation. The light gas, such as helium or hydrogen, is employed to keep the gas density low enough so as not to inhibit liner collapse.

  11. Measuring fuel contamination using high speed gas chromatography and cone penetration techniques

    SciTech Connect

    Farrington, S.P.; Bratton, W.L.; Akard, M.L.

    1995-10-01

    Decision processes during characterization and cleanup of hazardous waste sites are greatly retarded by the turnaround time and expense incurred through the use of conventional sampling and laboratory analyses. Furthermore, conventional soil and groundwater sampling procedures present many opportunities for loss of volatile organic compounds (VOC) by exposing sample media to the atmosphere during transfers between and among sampling devices and containers. While on-site analysis by conventional gas chromatography can reduce analytical turnaround time, time-consuming sample preparation procedures are still often required, and the potential for loss of VOC is not reduced. This report describes the development of a high speed gas chromatography and cone penetration testing system which can detect and measure subsurface fuel contamination in situ during the cone penetration process.

  12. Laser weld penetration estimation using temperature measurements

    SciTech Connect

    Lankalapalli, K.N.; Tu, J.F.; Leong, K.H.; Gartner, M.

    1997-10-01

    Penetration depth is an important factor critical to the quality of a laser weld. This paper examines the feasibility of using temperature measurements on the bottom surface of the work-piece to estimate weld penetration. A three-dimensional analytical model relating penetration depth, weld bead width and welding speed to temperature distribution at the bottom surface of the workpiece is developed. Temperatures on the bottom surface of the workpiece are measured using infrared thermocouples located behind the laser beam. Experimental results from bead-on-plate welds on low carbon steel plates of varying thickness at different levels of laser power and speeds validate the model and show that the temperature on the bottom surface is a sensitive indicator of penetration depth. The proposed model is computationally efficient and is suitable for on-line process monitoring application.

  13. Non-normal impact of earth penetrators

    SciTech Connect

    Duffey, T.A.; Macek, R.W.

    1996-12-31

    A brief literature review of the general subject of projectile penetration into soil media is presented. Particular emphasis is placed on projectiles impacting soil targets at other than normal incidence and/or at an angle of attack, for which lateral accelerations exist and can dominate the structural response. Comparisons of predicted lateral accelerations with recent earth penetrator experiments are then made using a 3 degree-of-freedom rigid-body approach developed elsewhere to determine the external penetrator loading. Agreement between experimental and calculated accelerations is favorable, but the need to include flexible-body response is indicated. Finally a scheme to incorporate a spherical-cavity-expansion analytical procedure into a detailed finite element model of the penetrator is developed to account for flexible-body response.

  14. Structural response measurements to insure penetrator data integrity

    SciTech Connect

    Bateman, V.I.; Mayes, R.L.; James, G.H. III

    1993-09-01

    Measurements made by a penetrator structure penetration of some medium may not measure the penetration environment directly. In general, the measurements quantify the penetrator`s structural response to the penetrator force environment. This paper reports laboratory testing and analysis techniques that have been used to identify and/or remove highly nonlinear responses which can mask the penetration environments one desires to measure. Results for two penetrator structures are presented. For the first penetrator, shock testing was conducted to determine the cause of accelerometer failure during field tests. For a second penetrator, shock testing was conducted to assist with the interpretation of accelerometer measurements made during field tests for which the penetrator was instrumented with one axial accelerometer. Very high acceleration levels for a data bandwidth of DC to 70 kHz were recorded in these field tests. The laboratory test results for these two penetrators are presented and discussed.

  15. Low Force Penetration of Icy Regolith

    NASA Technical Reports Server (NTRS)

    Mantovani, J. G.; Galloway, G. M.; Zacny, K.

    2016-01-01

    A percussive cone penetrometer measures the strength of granular material by using percussion to deliver mechanical energy into the material. A percussive cone penetrometer was used in this study to penetrate a regolith ice mixture by breaking up ice and decompacting the regolith. As compared to a static cone penetrometer, percussion allows low reaction forces to push a penetrometer probe tip more easily into dry regolith in a low gravity environment from a planetary surface rover or a landed spacecraft. A percussive cone penetrates icy regolith at ice concentrations that a static cone cannot penetrate. In this study, the percussive penetrator was able to penetrate material under 65 N of down-force which could not be penetrated using a static cone under full body weight. This paper discusses using a percussive cone penetrometer to discern changes in the concentration of water-ice in a mixture of lunar regolith simulant and ice to a depth of one meter. The rate of penetration was found to be a function of the ice content and was not significantly affected by the down-force. The test results demonstrate that this method may be ideal for a small platform in a reduced gravity environment. However, there are some cases where the system may not be able to penetrate the icy regolith, and there is some risk of the probe tip becoming stuck so that it cannot be retracted. It is also shown that a percussive cone penetrometer could be used to prospect for water ice in regolith at concentrations as high as 8 by weight.

  16. Penetrating intracranial nail-gun injury to the middle cerebral artery: A successful primary repair

    PubMed Central

    Isaacs, Albert M.; Yuh, Sung-Joo; Hurlbert, R. John; Mitha, Alim P.

    2015-01-01

    Background: Penetrating nail-gun injuries to the head are rare, however, the incidence has been gradually rising over the last decade. While there is a large volume of case reports in the literature, there are only a few incidences of cerebrovascular injury. We present a case of a patient with a nail-gun injury to the brain, which compromised the cerebral vasculature. In this article, we present the case, incidence, pathology, and a brief literature review of penetrating nail-gun injuries to highlight the principles of management pertaining to penetration of cerebrovascular structures. Case Description: A 26-year-old male presented with a penetrating nail-gun injury to his head. There were no neurological deficits. Initial imaging revealed that the nail had penetrated the cranium and suggested the vasculature to be intact. However, due to the proximity of the nail to the circle of Willis the operative approach was tailored in anticipation of a vascular injury. Intraoperatively removal of the foreign body demonstrated a laceration to the M1 branch of the middle cerebral artery (MCA), which was successfully repaired. Conclusion: To our knowledge, this is the first reported case of a vascular arterial injury to the MCA from a nail-gun injury. It is imperative to have a high clinical suspicion for cerebrovascular compromise in penetrating nail-gun injuries even when conventional imaging suggests otherwise. PMID:26500798

  17. Partial penetrance facilitates developmental evolution in bacteria

    PubMed Central

    Eldar, Avigdor; Chary, Vasant; Xenopoulos, Panagiotis; Fontes, Michelle E.; Loson, Oliver C.; Dworkin, Jonathan; Piggot, Patrick; Elowitz, Michael B.

    2009-01-01

    Development normally occurs similarly in all individuals within an isogenic population, but mutations often affect the fate of individual organisms differently1-4. This phenomenon, known as partial penetrance, has been observed in diverse developmental systems. However, it remains unclear how the underlying genetic network specifies the set of possible alternative fates and how the relative frequencies of these fates evolve5-8. Here, we identify a stochastic cell fate determination process that operates in Bacillus subtilis sporulation mutants and show how it allows genetic control of the penetrance of multiple fates. Mutations in an inter-compartmental signaling process generate a set of discrete alternative fates not observed in wild-type cells, including rare formation of two viable “twin” spores, rather than one within a single cell. By genetically modulating chromosome replication and septation, we could systematically tune the penetrance of each mutant fate. Furthermore, signaling and replication perturbations synergize to dramatically increase the penetrance of twin sporulation. These results suggest a potential pathway for developmental evolution between monosporulation and twin sporulation through states of intermediate twin penetrance. Furthermore, time-lapse microscopy of twin sporulation in wild-type Clostridium oceanicum showed a strong resemblance to twin sporulation in these B. subtilis mutants9,10. Together the results suggest that noise can facilitate developmental evolution by enabling the initial expression of discrete morphological traits at low penetrance, and allowing their stabilization by gradual adjustment of genetic parameters. PMID:19578359

  18. Penetration of Bdellovibrio bacteriovorus into Host Cells

    PubMed Central

    Abram, Dinah; e Melo, J. Castro; Chou, D.

    1974-01-01

    Electron microscopy reveals that, in Bdellovibrio infection, after the formation of a passage pore in the host cell wall, the differentiated parasite penetration pole is associated with the host protoplast. This firm contact persists throughout the parasite penetration and after this process is completed. In penetrated hosts this contact is also apparent by phase microscopy. The association between the walls of the parasite and the host at the passage pore, on the other hand, is transient. Bdellovibrio do not penetrate hosts whose protoplast and cell walls are separated by plasmolysis, or in which the membrane-wall relationship is affected by low turgor pressure. It is concluded, therefore, that for penetration to occur it is essential that the host protoplast be within reach of the parasite, so that a firm contact can be established between them. A penetration mechanism is proposed that is effected by forces generated by fluxes of water and solutes due to structural changes in the infected host envelope. These forces cause a differential expansion of the host protoplast and cell wall and their separation from each other around the entry site, while the parasite remains firmly anchored to the host protoplast. Consequently, the parasite ends up enclosed in the expanded host periplasm. The actual entry, therefore, is a passive act of the parasite. Images PMID:4208138

  19. ESD and the Rio Conventions

    ERIC Educational Resources Information Center

    Sarabhai, Kartikeya V.; Ravindranath, Shailaja; Schwarz, Rixa; Vyas, Purvi

    2012-01-01

    Chapter 36 of Agenda 21, a key document of the 1992 Earth Summit, emphasised reorienting education towards sustainable development. While two of the Rio conventions, the Convention on Biological Diversity (CBD) and the United Nations Framework Convention on Climate Change (UNFCCC), developed communication, education and public awareness (CEPA)…

  20. Are cognitive outcome and recovery different in civilian penetrating versus non-penetrating brain injuries?

    PubMed

    Ylioja, Shelley; Hanks, Robin; Baird, Anne; Millis, Scott

    2010-10-01

    The present study sought to determine whether cognitive outcome and course of recovery in civilian penetrating brain injury due to gunshot can be distinguished from that of non-penetrating brain injury due to motor vehicle accident. Matched survivors of penetrating and non-penetrating brain injury were assessed with a brief neuropsychological test battery at inpatient rehabilitation, 1 year post-injury, and 2 years post-injury. The traumatic brain injury groups were found to have patterns of performance marked by reliably distinct differences in isolated areas, with different cognitive predictors of brain injury type present in early versus later recovery. The degree of recovery over the first 2 years appeared to be quite similar for penetrating and non-penetrating injuries. PMID:20924980

  1. Modified deep anterior lamellar keratoplasty for the treatment of advanced keratoconus with steep corneal curvature to help in eliminating the wrinkles in the Descemet's membrane

    PubMed Central

    Khakshoor, Hamid; Eslampoor, Alireza; Rad, Saeed Shokoohi; Vejdani, Amirhossein

    2014-01-01

    Aims: To determine the clinical efficacy of modified deep anterior lamellar keratoplasty (DALK) for the treatment of advanced-stage keratoconus with steep curvature. Materials and Methods: In this interventional, non-comparative case series, 30 patients with advanced stages of keratoconus and curvature of more than 60 D underwent a modified DALK procedure. In this technique, after big-bubble formation, posterior stromal lamella was cut and removed 5 mm centrally (baring Descemet's membrane completely) with posterior stromal layer remaining peripherally. Results: The study included 30 eyes (30 patients with a mean ± SD age of 25 ± 5.4 years). The follow-up examination was performed for all participants up to 12 months after the surgery. The mean uncorrected visual acuity (UCVA) increased from 20/800 before the surgery to a subsequent 3/10 (P =0.12). Likewise, best spectacle corrected visual acuity (BSCVA) improved, reaching 6/10 postoperatively (former quantity 20/200) (P =0.18). In addition, mean keratometry and keratometric astigmatism managed to achieve considerable improvement, from 58.8 ± 5.4 D to 46.5 ± 2.1 D and 7.8 ± 2.1 to 4.54 ± 1.54 D, respectively (P =0.52). Descemet's membrane wrinkling was not seen in any patient postoperatively. Conclusions: This technique is effective in restoring acceptable vision and corneal regularity in advanced cases of keratoconus with a curvature more than 60 D who are also at risk of Descemet's membrane wrinkling after DALK. Therefore, this procedure could prevent from Descemet membrane wrinkling in such cases. PMID:24817742

  2. Urokinase-controlled tumor penetrating peptide.

    PubMed

    Braun, Gary B; Sugahara, Kazuki N; Yu, Olivia M; Kotamraju, Venkata Ramana; Mölder, Tarmo; Lowy, Andrew M; Ruoslahti, Erkki; Teesalu, Tambet

    2016-06-28

    Tumor penetrating peptides contain a cryptic (R/K)XX(R/K) CendR element that must be C-terminally exposed to trigger neuropilin-1 (NRP-1) binding, cellular internalization and malignant tissue penetration. The specific proteases that are involved in processing of tumor penetrating peptides identified using phage display are not known. Here we design de novo a tumor-penetrating peptide based on consensus cleavage motif of urokinase-type plasminogen activator (uPA). We expressed the peptide, uCendR (RPARSGR↓SAGGSVA, ↓ shows cleavage site), on phage or coated it onto silver nanoparticles and showed that it is cleaved by uPA, and that the cleavage triggers binding to recombinant NRP-1 and to NPR-1-expressing cells. Upon systemic administration to mice bearing uPA-overexpressing breast tumors, FAM-labeled uCendR peptide and uCendR-coated nanoparticles preferentially accumulated in tumor tissue. We also show that uCendR phage internalization into cultured cancer cells and its penetration in explants of murine tumors and clinical tumor explants can be potentiated by combining the uCendR peptide with tumor-homing module, CRGDC. Our work demonstrates the feasibility of designing tumor-penetrating peptides that are activated by a specific tumor protease. As upregulation of protease expression is one of the hallmarks of cancer, and numerous tumor proteases have substrate specificities compatible with proteolytic unmasking of cryptic CendR motifs, the strategy described here may provide a generic approach for designing proteolytically-actuated peptides for tumor-penetrative payload delivery. PMID:27106816

  3. NV Energy Solar Integration Study: Cycling and Movements of Conventional Generators for Balancing Services

    SciTech Connect

    Diao, Ruisheng; Lu, Shuai; Etingov, Pavel V.; Ma, Jian; Makarov, Yuri V.; Guo, Xinxin

    2011-07-01

    With an increasing penetration level of solar power in the southern Nevada system, the impact of solar on system operations needs to be carefully studied from various perspectives. Qualitatively, it is expected that the balancing requirements to compensate for solar power variability will be larger in magnitude; meanwhile, generators providing load following and regulation services will be moved up or down more frequently. One of the most important tasks is to quantitatively evaluate the cycling and movements of conventional generators with solar power at different penetration levels. This study is focused on developing effective methodologies for this goal and providing a basis for evaluating the wear and tear of the conventional generators

  4. Polymeric penetration enhancers promote humoral immune responses to mucosal vaccines.

    PubMed

    Klein, Katja; Mann, Jamie F S; Rogers, Paul; Shattock, Robin J

    2014-06-10

    Protective mucosal immune responses are thought best induced by trans-mucosal vaccination, providing greater potential to generate potent local immune responses than conventional parenteral vaccination. However, poor trans-mucosal permeability of large macromolecular antigens limits bioavailability to local inductive immune cells. This study explores the utility of polymeric penetration enhancers to promote trans-mucosal bioavailability of insulin, as a biomarker of mucosal absorption, and two vaccine candidates: recombinant HIV-1 envelope glycoprotein (CN54gp140) and tetanus toxoid (TT). Responses to vaccinating antigens were assessed by measurement of serum and the vaginal humoral responses. Polyethyleneimine (PEI), Dimethyl-β-cyclodextrin (DM-β-CD) and Chitosan enhanced the bioavailability of insulin following intranasal (IN), sublingual (SL), intravaginal (I.Vag) and intrarectal (IR) administration. The same penetration enhancers also increased antigen-specific IgG and IgA antibody responses to the model vaccine antigens in serum and vaginal secretions following IN and SL application. Co-delivery of both antigens with PEI or Chitosan showed the highest increase in systemic IgG and IgA responses following IN or SL administration. However the highest IgA titres in vaginal secretions were achieved after IN immunisations with PEI and Chitosan. None of the penetration enhancers were able to increase antibody responses to gp140 after I.Vag immunisations, while in contrast PEI and Chitosan were able to induce TT-specific systemic IgG levels following I.Vag administration. In summary, we present supporting data that suggest appropriate co-formulation of vaccine antigens with excipients known to influence mucosal barrier functions can increase the bioavailability of mucosally applied antigens promoting the induction of mucosal and systemic antibody responses. PMID:24657807

  5. Synthesis and processing of composites by reactive metal penetration

    SciTech Connect

    Loehman, R.E.; Ewsuk, K.G.; Tomsia, A.P.

    1997-04-01

    Achieving better performance in commercial products and processes often is dependent on availability of new and improved materials. Ceramic-metal composites have advantages over more conventional materials because of their high stiffness-to-weight ratios, good fracture toughness, and because their electrical and thermal properties can be varied through control of their compositions and microstructures. However, ceramic composites will be more widely used only when their costs are competitive with other materials and when designers have more confidence in their reliability. Over the past four years reactive metal penetration has been shown to be a promising technique for making ceramic and metal-matrix composites to near-net-shape with control of both composition and microstructure. It appears that, with sufficient development, reactive metal penetration could be an economical process for manufacturing many of the advanced ceramic composites that are needed for light-weight structural and wear applications for transportation and energy conversion devices. Near-net-shape fabrication of parts is a significant advantage because costly and energy intensive grinding and machining operations are substantially reduced, and the waste generated from such finishing operations is minimized. The most promising compositions to date consist of Al and Al{sub 2}O{sub 3}; thus, these composites should be of particular interest to the aluminum industry. The goals of this ceramic-metal composite research and development program are: (1) to identify compositions favorable for making composites by reactive metal penetration; (2) to understand the mechanism(s) by which these composites are formed; (3) to control and optimize the process so that composites and composite coatings can be made economically; and (4) to apply R&D results to problems of interest to the aluminum industry.

  6. Optimized support vector regression for drilling rate of penetration estimation

    NASA Astrophysics Data System (ADS)

    Bodaghi, Asadollah; Ansari, Hamid Reza; Gholami, Mahsa

    2015-12-01

    In the petroleum industry, drilling optimization involves the selection of operating conditions for achieving the desired depth with the minimum expenditure while requirements of personal safety, environment protection, adequate information of penetrated formations and productivity are fulfilled. Since drilling optimization is highly dependent on the rate of penetration (ROP), estimation of this parameter is of great importance during well planning. In this research, a novel approach called `optimized support vector regression' is employed for making a formulation between input variables and ROP. Algorithms used for optimizing the support vector regression are the genetic algorithm (GA) and the cuckoo search algorithm (CS). Optimization implementation improved the support vector regression performance by virtue of selecting proper values for its parameters. In order to evaluate the ability of optimization algorithms in enhancing SVR performance, their results were compared to the hybrid of pattern search and grid search (HPG) which is conventionally employed for optimizing SVR. The results demonstrated that the CS algorithm achieved further improvement on prediction accuracy of SVR compared to the GA and HPG as well. Moreover, the predictive model derived from back propagation neural network (BPNN), which is the traditional approach for estimating ROP, is selected for comparisons with CSSVR. The comparative results revealed the superiority of CSSVR. This study inferred that CSSVR is a viable option for precise estimation of ROP.

  7. Enhanced chlorhexidine skin penetration with eucalyptus oil

    PubMed Central

    2010-01-01

    Background Chlorhexidine digluconate (CHG) is a widely used skin antiseptic, however it poorly penetrates the skin, limiting its efficacy against microorganisms residing beneath the surface layers of skin. The aim of the current study was to improve the delivery of chlorhexidine digluconate (CHG) when used as a skin antiseptic. Method Chlorhexidine was applied to the surface of donor skin and its penetration and retention under different conditions was evaluated. Skin penetration studies were performed on full-thickness donor human skin using a Franz diffusion cell system. Skin was exposed to 2% (w/v) CHG in various concentrations of eucalyptus oil (EO) and 70% (v/v) isopropyl alcohol (IPA). The concentration of CHG (μg/mg of skin) was determined to a skin depth of 1500 μm by high performance liquid chromatography (HPLC). Results The 2% (w/v) CHG penetration into the lower layers of skin was significantly enhanced in the presence of EO. Ten percent (v/v) EO in combination with 2% (w/v) CHG in 70% (v/v) IPA significantly increased the amount of CHG which penetrated into the skin within 2 min. Conclusion The delivery of CHG into the epidermis and dermis can be enhanced by combination with EO, which in turn may improve biocide contact with additional microorganisms present in the skin, thereby enhancing antisepsis. PMID:20860796

  8. Environmental SEM and dye penetration observation on resin-tooth interface using different light curing method.

    PubMed

    Yoshikawa, Takako; Morigami, Makoto; Sadr, Alireza; Tagami, Junji

    2016-01-01

    The aim of this study was the effects of different light curing methods on marginal sealing and resin composite adaptation to the cavity wall using the dye penetration test and environmental scanning electron microscope (SEM) observations. Cylindrical cavities were prepared on cervical regions. The teeth were restored with Clearfil Liner Bond 2 V adhesive and filled with Clearfil Photo Bright or Palfique Estelite resin composites. These resins were cured with a conventional light-curing method or a slow-start curing method. After thermal cycling, the specimens were subjected to the dye penetration test to evaluate marginal sealing and adaptation of the resin composites to the cavity walls. These resin-tooth interfaces were then observed using environmental SEM. The light-cured resin composite, which exhibited increased contrast ratios during polymerization, suggests high compensation for polymerization stress using the slow-start curing method. There was a high correlation between dye penetration test and environmental SEM observation. PMID:26830828

  9. Penetrators (penetrating sondes) and new possibilities for study of the planets

    NASA Technical Reports Server (NTRS)

    Davydov, V. D.; Skuridin, G. A.

    1979-01-01

    The fields of possible use of penetrators in space research are considered. A survey of the condition of development and plans for use of penetrators abroad is presented and an analysis is given of the significance of scientific problems when probing planets.

  10. Sunshot Initiative High Penetration Solar Portal

    DOE Data Explorer

    The DOE SunShot Initiative is a collaborative national initiative to make solar energy cost-competitive with other forms of energy by the end of the decade. Reducing the installed cost of solar energy systems by about 75% will drive widespread large-scale adoption of this renewable energy and restore U.S. leadership in the global clean energy race. The High Penetration Solar Portal was created as a resource to aggregate the most relevant and timely information related to high penetration solar scenarios and integrating solar into the grid. The site is designed so that utilities, grant awardees, regulators, researchers, and other solar professionals can easily share data, case studies, lessons learned, and demonstration project findings. [from https://solarhighpen.energy.gov/about_the_high_penetration_solar_portal

  11. Compressibility effects in shaped charge jet penetration

    NASA Astrophysics Data System (ADS)

    Haugstad, B. S.

    1981-03-01

    Among other hypotheses, the classical theory of high-speed penetration assumes the incompressibility of both the projectile and target. Employing a simple Murnaghan equation of state, we show here that direct compressibility effects (pv-work) on penetration depth are at most on the order of 10-15% for projectile speeds as high as 104 ms-1. Our results agree closely with similar results by Coombs (private communication, Royal Air Force Research Establishment, 1978), who used a more complex five-parameter equation of state. This indicates that rather simple equations of state may adequately represent essential thermodynamic features of high-speed penetration phenomena. The equation of state employed here furthermore allows approximate analytical results to be derived for both small and large projectile velocities.

  12. METHOD AND APPARATUS FOR EARTH PENETRATION

    DOEpatents

    Adams, W.M.

    1963-12-24

    A nuclear reactor apparatus for penetrating into the earth's crust is described. The apparatus comprises a cylindrical nuclear core operating at a temperature that is higher than the melting temperature of rock. A high-density ballast member is coupled to the nuclear core such that the overall density of the core-ballast assembly is greater than the density of molten rock. The nuclear core is thermally insulated so that its heat output is constrained to flow axially, with radial heat flow being minimized. In operation, the apparatus is placed in contact with the earth's crust at the point desired to be penetrated. The heat output of the reactor melts the underlying rock, and the apparatus sinks through the resulting magma. The fuel loading of the reactor core determines the ultimate depth of crust penetration. (AEC)

  13. Penetration drag in loosely packed granular materials

    NASA Astrophysics Data System (ADS)

    Bless, Stephan; Omidvar, Mehdi; Iskander, Magued; New York University Collaboration

    2015-03-01

    The drag coefficient for penetration of granular materials by conical-nosed penetrators was computed by assuming the particles are non-interacting and rebound elastically off of the advancing penetrator. The solution was C =4 [sin(theta)]**2, where theta is the half angle of the cone. Experiments were conducted in which the drag coefficient was measured over the range 30 to 80 m/s for four types of sand: Ottawa silica sand, crushed quartz glass, coral sand, and aragonite sand. The sands were tested at relative densities of 40 and 80%. The drag coefficients for the low density materials were in excellent agreement with this simple model. The high density material had a drag considerably larger than predicted, presumably because of particle-to-particle interactions.

  14. Penetrative Convection and Zonal Flow on Jupiter

    PubMed

    Zhang; Schubert

    1996-08-16

    Measurements by the Galileo probe support the possibility that the zonal winds in Jupiter's atmosphere originate from convection that takes place in the deep hydrogen-helium interior. However, according to models based on recent opacity data and the probe's temperature measurements, there may be radiative and nonconvective layers in the outer part of the jovian interior, raising the question of how deep convection could extend to the surface. A theoretical model is presented to demonstrate that, because of predominant rotational effects and spherical geometry, thermal convection in the deep jovian interior can penetrate into any outer nonconvective layer. These penetrative convection rolls interact nonlinearly and efficiently in the model to generate and sustain a mean zonal wind with a larger amplitude than that of the nonaxisymmetric penetrative convective motions, a characteristic of the wind field observed at the cloud level on Jupiter. PMID:8688074

  15. Development Of The Nuclear Optical Penetration

    NASA Astrophysics Data System (ADS)

    Inoue, K.; Koike, K.; Imada, Y.

    1984-10-01

    We have developed the nuclear optical penetration to be incorporated in the wall penetration of the shell to introduce a data transmission system using optical fibers into a nuclear power plant with a pressurized water reactor. Radiation-induced coloration in optical glass seriously affects transmission characteristics of optical fibers, whereas it has been revealed that the pure-silica core optical fiber without any dopant in the core has wide applicability in radiation fields thanks to its very low radiation-induced attenuation. The wall penetration of the shell should have airtightness and resistivity to heat, vibration, and pressure, let alone radiation, excellent enough to be invariable in data transmission efficiency even when subjected to severe environmental tests. The sealing modules of this newly developed nuclear optical penetration are hermetically sealed. The gap between the optical fiber rod (100 pm in core diameter and 5 mm in rod diameter) and stainless steel tube is sealed with lamingted glass layer. As the result of He gas leakage test, high airtightness of less than 10 cc/sec was achieved. No thermal deformation of the core was caused by sealing with laminated glass layer, nor was observed transmission loss. Then the sealiing modules were subjected to the irradiation test using 60 Co gamma ray exposure of 2 x 10 rads. Though silica glass layer supporting the fiber rod and sealing glass portion turned blackish purple, transparency of the fiber was not affected. Only less than 0.5 dB of connecting loss was observed at the connecting point with the optical fiber cable. The sealing modules were also found to have resistivity to vibration and pressure as excellent as that of existing nuclear electric penetrations. We expect the nuclear optical fiber penetration will be much effective in improving reliability of data transmission systems using optical fibers in radiation fields.

  16. Surfactant improves irrigant penetration into unoperated sinuses

    PubMed Central

    Rohrer, Joseph W.; Dion, Greg R.; Brenner, Pryor S.; Abadie, Wesley M.; McMains, Kevin C.; Thomas, Roy F.

    2012-01-01

    Background: Saline irrigations are proving to be a valuable intervention in the treatment of chronic sinusitis. The use of surfactants is a well established additive to topical treatments known to reduce surface tension and may prove to be a simple, nonoperative intervention to improve intrasinus douching penetration. Methods: Six 30-mL, flat-bottomed medicine cups with circular holes cut through the bottom center and varying in diameter from 1 to 6 mm were created with punch biopsies. Water, saline, saline/dye, and saline/dye/surfactant were compared for maximum holding pressure via these modeled ostia. Holding pressures also were determined for cups with septal mucosa fused to the bottom with holes ranging from 1 to 6 mm. In addition, analysis was carried out with blood and blood/surfactant. Finally, five thawed, fresh-frozen cadaver heads were evaluated before any sinus surgery with water/dye and water/dye/surfactant for intrasinus penetration. Results: Surfactant significantly improved the ability of all solutions to penetrate ostia in both the plastic cup and fused septal mucosa model. All nonsurfactant-containing solutions were not statistically different from one another, nor did surfactant change the ostial penetration of blood. Surfactant significantly improved the ability of sinus irrigant to penetrate unoperated sinus cavities (3.12 vs 3.5, p = .021). Conclusions: The addition of surfactant to saline irrigation improves ostial penetration in undissected and undiseased cadavers. This has practical implications for unoperated patients seeking care for sinus-related symptoms in that we have now described a method for improving topical treatment of target sinus mucosa prior to surgical intervention. PMID:22643945

  17. Hydraulic well penetration apparatus and method

    SciTech Connect

    Schellstede, H.J.; McQueen, R.W.; Peters, A.D.

    1988-12-13

    This patient describes a method of penetrating a well casing and surrounding earth strata comprising the steps of: positioning a punch member internally of the casing at a desired depth in alignment with strata desired to be penetrated; and forcing the punch member outwardly through the casing to an extended position to effect the provision of an aperture in the casing while simultaneously moving a jet nozzle means outwardly through the punch member while concurrently providing a high pressure liquid jet from the nozzle means to effect the application of force to the casing to weaken the casing and aid the operation of the punch in cutting the case and surrounding strata.

  18. Optical penetration sensor for pulsed laser welding

    DOEpatents

    Essien, Marcelino; Keicher, David M.; Schlienger, M. Eric; Jellison, James L.

    2000-01-01

    An apparatus and method for determining the penetration of the weld pool created from pulsed laser welding and more particularly to an apparatus and method of utilizing an optical technique to monitor the weld vaporization plume velocity to determine the depth of penetration. A light source directs a beam through a vaporization plume above a weld pool, wherein the plume changes the intensity of the beam, allowing determination of the velocity of the plume. From the velocity of the plume, the depth of the weld is determined.

  19. FREEFALL: A seabed penetrator flight code

    SciTech Connect

    Hickerson, J.

    1988-01-01

    This report presents a one-dimensional model and computer program for predicting the motion of seabed penetrators. The program calculates the acceleration, velocity, and depth of a penetrator as a function of time from the moment of launch until the vehicle comes to rest in the sediment. The code is written in Pascal language for use on a small personal computer. Results are presented as printed tables and graphs. A comparison with experimental data is given which indicates that the accuracy of the code is perhaps as good as current techniques for measuring vehicle performance. 31 refs., 12 figs., 5 tabs.

  20. Explosive shaped charge penetration into tuff rock

    SciTech Connect

    Vigil, M.G.

    1988-10-01

    Analysis and data for the use of Explosive Shaped Charges (ESC) to generate holes in tuff rock formation is presented. The ESCs evaluated include Conical Shaped Charges (CSC) and Explosive Formed Projectiles (EFP). The CSCs vary in size from 0.158 to 9.1 inches inside cone diameter. The EFPs were 5.0 inches in diameter. Data for projectile impact angles of 30 and 90 degrees are presented. Analytically predicted depth of penetration data generally compared favorably with experimental data. Predicted depth of penetration versus ESC standoff data and hole profile dimensions in tuff are also presented. 24 refs., 45 figs., 6 tabs.

  1. HMO penetration: has it hurt public hospitals?

    PubMed

    Clement, J P; Grazier, K L

    2001-01-01

    The purpose of this study is to determine the extent to which health maintenance organization (HMO) penetration within the public hospitals' market area affects the financial performance and viability of these institutions, relative to private hospitals. Hospital- and market-specific measures are examined in a fully interacted model of over 2,300 hospitals in 321 metropolitan statistical areas (MSAs) in 1995. Although hospitals located in markets with higher HMO penetration have lower financial performance as reflected in revenues, expenses and operating margin, public hospitals are not more disadvantaged than other hospitals by managed care. PMID:11669291

  2. Penetrating Trauma to the Parotid Gland.

    PubMed

    Tisch, Matthias; Maier, Susanne; Maier, Heinz

    2015-08-01

    Penetrating trauma to the parotid gland may present unique challenges especially when Stensen duct, neurovascular structures, and/or collateral organs are involved. Especially ballistic injuries caused by high-velocity projectiles or fragments of grenades and improvised explosive devices are often associated with massive tissue damage and a high risk of infections and other posttraumatic complications. Because penetrating parotid trauma is not very common, only limited information on the primary treatment of such injuries is available. This article gives a short overview about actual aspects on diagnosis and treatment strategies especially focusing on ballistic parotid injuries. PMID:26372712

  3. The effect of welding parameters on penetration in GTA welds

    SciTech Connect

    Shirali, A.A. ); Mills, K.C. )

    1993-07-01

    The effect of various welding parameters on the penetration of GTA welds has been investigated. Increases in welding speed were found to reduce penetration; however, increases in welding current were observed to increase the penetration in high sulfur (HS) casts and decrease penetration in low sulfur (LS) steels. Plots of penetration as a function of increasing linear energy (the heat supplied per unit length of weld) revealed a similar trend with increased penetration in HS casts, but the penetration in LS casts was unaffected by increases in linear energy. These results support the Burgardt-Heiple proposition that changes in welding parameters on penetration can be explained in terms of their effect, sequentially, on the temperature gradient and the Marangoni forces operating in the weld pool. Increases in arc length were found to decrease weld penetration regardless of the sulfur concentration of the steel, and the effects of electrode geometry and welding position on weld penetration were also investigated.

  4. Single And Multiple Jet Penetration Experiments Into Geologic Materials

    SciTech Connect

    Kuklo, R; Murphy, M J; Rambur, T A; Switzer, L L; Summers, M A

    2003-12-19

    This paper presents the results of experiments that investigate the effect of single and multiple jet penetration into geologic materials. In previous studies of jet penetration into concrete targets, we demonstrated that an enhanced surface crater could be created by the simultaneous penetration of multiple shaped charge jets and that an enhanced target borehole could be created by the subsequent delayed penetration of a single shaped charge jet. This paper describes an extension of the multiple jet penetration research to limestone and granite.

  5. Comparison of Penetration of Irrigant Activated by Traditional Methods with A Novel Technique

    PubMed Central

    Kanumuru, Pavan Kumar; Sooraparaju, Sujatha Gopal; Nujella, Surya Kumari; Reddy, Bala Kasi; Penigalapati, Siva Ram

    2015-01-01

    Introduction The effectiveness of irrigation depends upon various irrigation activation methods & devices used. Aim To compare and evaluate the penetration of irrigant upto working length and into simulated lateral canals using four different irrigation activation techniques. Materials and Methods The root canals of 60 single-rooted teeth were instrumented using the proTaper rotary system. After decalcification of each sample tooth, three simulated lateral canals were created at 2mm, 4mm and 6mm levels from the root apex using a 06-size C+ file. After clearing the samples they were randomly assigned into four experimental groups (n=15) and 1ml of Irrigating Contrast Solution (ICS) was delivered into all samples and then it is activated with 4 different methods Group I-Conventional syringe and needle, Group II - Sonic activation with Endo activator, Group III – Ultrasonic activation with ultrasonic tips and Group IV - Activation using reciprocation movement. All the samples were examined under a stereomicroscope and irrigant penetration was evaluated by means of penetration of ICS. Results Group III and Group IV resulted in better penetration of ICS into lateral canals at 2mm and 4mm depth (p<0.001), when compared with Group I and II. At lateral canals 6mm all the groups except Group I, had shown 100 % penetration. Conclusion The activation of irrigant using reciprocation was able to achieve penetration of irrigating contrast solution both up to the working length and into lateral canals. Hence the clinical significance of this method of irrigant activation is that it can be used for effective penetration of irrigants both upto working length and into lateral canals. PMID:26674879

  6. FRAMEWORK CONVENTION ON CLIMATE CHANGE

    EPA Science Inventory

    The United Nations Framework Convention on ClimateChange is the first binding international legal instrument that deals directly with climate change. The Convention was adopted on 9 May 1992 after negotiations by the UN-sponsored Intergovernmental Negotiating Committee for aFra...

  7. Computed tomographic findings in penetrating peptic ulcer

    SciTech Connect

    Madrazo, B.L.; Halpert, R.D.; Sandler, M.A.; Pearlberg, J.L.

    1984-12-01

    Four cases of peptic ulcer penetrating the head of the pancreas were diagnosed by computed tomography (CT). Findings common to 3 cases included (a) an ulcer crater, (b) a sinus tract, and (c) enlargement of the head of the pancreas. Unlike other modalities, the inherent spatial resolution of CT allows a convenient diagnosis of this important complication of peptic ulcer disease.

  8. 7 CFR 3201.14 - Penetrating lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... The designation can be found in the Comprehensive Procurement Guideline, 40 CFR 247.11. ... Designated Items § 3201.14 Penetrating lubricants. (a) Definition. Products formulated to provide light... the product as a percent of the weight (mass) of the total organic carbon in the finished product....

  9. A Quantitative Analysis of Worldwide VCR Penetration.

    ERIC Educational Resources Information Center

    Lin, Carolyn

    By examining relationships between a host of national policy, domestic economic, media system, and media infrastructure factors, a study assesses possible predictors for videotape cassette recorder (VCR) penetration across 63 countries. Overall statistical results generated through hypothesis testing indicated that these factors were relatively…

  10. Planetary penetrators: Their origins, history and future

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2011-08-01

    Penetrators, which emplace scientific instrumentation by high-speed impact into a planetary surface, have been advocated as an alternative to soft-landers for some four decades. However, such vehicles have yet to fly successfully. This paper reviews in detail, the origins of penetrators in the military arena, and the various planetary penetrator mission concepts that have been proposed, built and flown. From the very limited data available, penetrator developments alone (without delivery to the planet) have required ˜$30M: extensive analytical instrumentation may easily double this. Because the success of emplacement and operation depends inevitably on uncontrollable aspects of the target environment, unattractive failure probabilities for individual vehicles must be tolerated that are higher than the typical '3-sigma' (99.5%) values typical for spacecraft. The two pathways to programmatic success, neither of which are likely in an austere financial environment, are a lucky flight as a 'piggyback' mission or technology demonstration, or with a substantial and unprecedented investment to launch a scientific (e.g. seismic) network mission with a large number of vehicles such that a number of terrain-induced failures can be tolerated.

  11. Subsurface investigation with ground penetrating radar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ground penetrating radar (GPR) data was collected on a small test plot at the OTF/OSU Turfgrass Research & Education Facility in Columbus, Ohio. This test plot was built to USGA standards for a golf course green, with a constructed sand layer just beneath the surface overlying a gravel layer, that i...

  12. Penetrating ocular trauma associated with blank cartridge

    PubMed Central

    2014-01-01

    Background Blank cartridge guns are generally regarded as being harmless and relative safe. However recent published articles demonstrated that the gas pressure from the exploding propellant of blank cartridge is powerful enough to penetrate the thoracic wall, abdominal muscle, small intestine and the skull. And there has been a limited number of case reports of ocular trauma associated with blank cartridge injury. In addition, no report on case with split extraocular muscle injury with traumatic cataract and penetrating corneoscleral wound associated with blank cartridge has been previously documented. This report describes the case of patient who sustained penetrating ocular injury with extraocular muscle injury by a close-distance blank cartridge that required surgical intervention. Case presentation A 20-year-old man sustained a penetrating globe injury in the right eye while cleaning a blank cartridge pistol. His uncorrected visual acuity at presentation was hand motion and he had a flame burn of his right upper and lower lid with multiple missile wounds. On slit-lamp examination, there was a 12-mm laceration of conjunctiva along the 9 o'clock position with two pinhole-like penetrating injuries of cornea and sclera. There was also a 3-mm corneal laceration between 9 o'clock and 12 o'clock and the exposed lateral rectus muscle was split. Severe Descemet's membrane folding with stromal edema was observed, and numerous yellow, powder-like foreign bodies were impacted in the cornea. Layered anterior chamber bleeding with traumatic cataract was also noted. Transverse view of ultrasonography showed hyperechoic foreign bodies with mild reduplication echoes and shadowing. However, a computed tomographic scan using thin section did not reveal a radiopaque foreign body within the right globe. Conclusion To our best knowledge, this is the first case report of split extraocular muscle injury with traumatic cataract and penetrating ocular injury caused by blank cartridge

  13. Aerosol penetration behavior of respirator valves.

    PubMed

    Brosseau, L M

    1998-03-01

    Exhalation and inhalation valves from half-facepiece negative pressure respirators were evaluated for leakage during an 8-hour cyclic breathing test period using two work rates (415 and 622 kg-m/min) and two particle sizes (0.3 and 0.8 micron). Three different models (manufacturers) of exhalation valves were tested, with two lots for each model. Exhalation valve leakage ranged from 0.0 to 0.03%; no failure of exhalation valves occurred. No differences in lot or manufacturer were found. Differences in particle size did not lead to differences in penetration at the lower work rate; at the higher work rate 0.3-micron particles were less penetrating than 0.8-micron particles (0.03 versus 0.06%). When tested for air leakage at a pressure of 2.54 cm H2O, following the National Institute for Occupational Safety and Health certification method, exhalation valves exhibited no leakage either before or after the experiments. Inhalation valves averaged 20% leakage for all experiments; 0.3-micron particles were again less penetrating (13%) than 0.8-micron particles (27%). No inhalation valve failure occurred. No differences in lot (within manufacturer) were found; there were, however, significant differences in particle penetration among the three manufacturers' inhalation valves. Airflow leakage through the inhalation valves did not change during the experimental period, but differed among the three manufacturers. Measurements using airflow leakage and particle penetration produced the same ranking for the three manufacturers' inhalation valves. PMID:9530803

  14. Penetration of tamoxifen citrate loaded ethosomes and liposomes across human skin: a comparative study with confocal laser scanning microscopy.

    PubMed

    Sarwa, Khomendra K; Suresh, Preeti K; Rudrapal, Mithun; Verma, Vinod K

    2014-01-01

    In the present study, ethosomal and liposomal formulations containing tamoxifen citrate were prepared and evaluated for their penetration properties in human cadaver skin using Franz diffusion cell and confocal laser scanning microscope (CLSM). The results clearly revealed that ethosomal vesicles showed a better drug permeation profile than that of liposomal vesicles. In addition, low fluorescence intensity in CLSM was recorded with liposomes as compared to ethosomes, indicating lower cumulative amount of drug permeation from liposomal vesicles. Furthermore, CLSM showed uniform fluorescence intensity across the entire depth of skin in ethosomal treatment, indicating high penetrability of ethosomal vesicles through human cadaver skin. In contrast, low penetrability of conventional liposomal vesicles was recorded as penetration was limited to the 7(th) section (i.e. upper epidermis layer) of skin as evident from visualization of intact liposomal vesicles in CLSM. PMID:24428443

  15. Push-out bond strength and dentinal tubule penetration of different root canal sealers used with coated core materials

    PubMed Central

    Purali, Nuhan; Coşgun, Erdal; Calt, Semra

    2016-01-01

    Objectives The aim of this study was to compare the push-out bond strength and dentinal tubule penetration of root canal sealers used with coated core materials and conventional gutta-percha. Materials and Methods A total of 72 single-rooted human mandibular incisors were instrumented with NiTi rotary files with irrigation of 2.5% NaOCl. The smear layer was removed with 17% ethylenediaminetetraacetic acid (EDTA). Specimens were assigned into four groups according to the obturation system: Group 1, EndoRez (Ultradent Product Inc.); Group 2, Activ GP (Brasseler); Group 3, SmartSeal (DFRP Ltd. Villa Farm); Group 4, AH 26 (Dentsply de Trey)/gutta-percha (GP). For push-out bond strength measurement, two horizontal slices were obtained from each specimen (n = 20). To compare dentinal tubule penetration, remaining 32 roots assigned to 4 groups as above were obturated with 0.1% Rhodamine B labeled sealers. One horizontal slice was obtained from the middle third of each specimen (n = 8) and scanned under confocal laser scanning electron microscope. Tubule penetration area, depth, and percentage were measured. Kruskall-Wallis test was used for statistical analysis. Results EndoRez showed significantly lower push-out bond strength than the others (p < 0.05). No significant difference was found amongst the groups in terms of percentage of sealer penetration. SmartSeal showed the least penetration than the others (p < 0.05). Conclusions The bond strength and sealer penetration of resin-and glass ionomer-based sealers used with coated core was not superior to resin-based sealer used with conventional GP. Dentinal tubule penetration has limited effect on bond strength. The use of conventional GP with sealer seems to be sufficient in terms of push-out bond strength. PMID:27200279

  16. Laryngeal penetration during deglutition in normal subjects of various ages.

    PubMed

    Daggett, Alicia; Logemann, Jeri; Rademaker, Alfred; Pauloski, Barbara

    2006-10-01

    This study examined the frequency of penetration of liquid, paste, and masticated materials into the airway during videofluoroscopic studies of normal swallow in 98 normal subjects who were from 20 to 94 years of age. The purposes of the study were to define frequency and level of penetration using the penetration-aspiration scale as a result of age, bolus volume, viscosity, and gender, and to describe the body's sensorimotor response to the penetration based on audible coughs or throat clearing on the audio channel of each videotaped fluoroscopic study. Frequencies of penetration were defined in relation to bolus volume, age, gender, and bolus viscosity from swallows of 1, 3, 5, and 10 ml and cup-drinking of thin liquids; 3 ml of pudding; (1/4) of a Lorna Doone cookie; and a bite of an apple. Results showed that penetrations were significantly more frequent after age 50 and thick viscosities penetrated only in subjects age 50 and over. For persons under 50, 7.4% of swallows exhibited penetration, while for people age 50 and over, 16.8% of swallows showed penetration. Significantly more penetration occurred on larger liquid boluses. There was no relationship between gender and frequency of penetration. None of the subjects that penetrated showed a sensorimotor response to the penetration, which may relate to the relatively shallow depth of the penetration. PMID:17216388

  17. The inappropriateness of conventional cephalometrics.

    PubMed

    Moyers, R E; Bookstein, F L

    1979-06-01

    1. Cephalometric conventions today may have little basis in either biology or biometrics. 2. There is no theory of cephalometrics, only conventions which involve landmarks and straight lines only. These fail to capture the curving of form and its changes, exclude proper measures of size for bent structures, and misrepresent growth, portraying it as vector displacement rather than a generalized distortion. 3. Conventional cephalometric procedures misinform by fabrication of misleading geometric quantities, by camouflage, particularly of remodeling, by confusion about what is happening (analysis of rotations, treating shape separately from size, and registering angles on landmarks as vertices), and by subtraction as a representation of growth. 4. We suggest that the present systems offer little real hope of improvement sufficient to meet our needs in craniofacial growth research. We call attention to three possible techniques to be included in future cephalometric conventions: (1) tangents and curvatures, (2) Blum's medial axis ("skeleton"), and (3) biorthogonal grids. PMID:287374

  18. Penetration into low-density media: In situ observation of penetration process of various projectiles

    NASA Astrophysics Data System (ADS)

    Kadono, Toshihiko; Niimi, Rei; Okudaira, Kyoko; Hasegawa, Sunao; Tabata, Makoto; Tsuchiyama, Akira

    2012-11-01

    In order to understand the penetration process of projectiles into lower-density targets, we carry out hypervelocity impact experiments using low-density (60 mg cm-3) aerogel targets and various types of projectiles, and observe the track formation process in the targets using a high-speed camera. A carrot shaped track, a bulbous, and a “hybrid” one consisting of bulbous and thin parts, are formed. The results of the high-speed camera observations reveal the similarity and differences on the temporal evolution of the penetration depth and maximum diameter of these tracks. At very early stages of an impact, independent of projectile type, the temporal penetration depth is described by hydrodynamic models for the original projectiles. Afterward, when the breakup of projectiles does not occur, intact projectiles continue to penetrate the aerogels. In the case of the breakup of projectiles, the track expands with a velocity of about a sound velocity of the aerogel at final stages. If there are large fragments, they penetrate deeper and the tracks become a hybrid type. The penetration of the large fragments is described by hydrodynamic models. Based on these results, we discuss the excavation near the impact point by shock waves.

  19. Penetrating Heart Injury due to Screwdriver Assault

    PubMed Central

    Dieng, P. A.; Diop, M. S.; Ciss, A. G.; Ba, P. S.; Diatta, S.; Gaye, M.; Fall, M. L.; Ndiaye, A.; Ndiaye, M.

    2015-01-01

    Penetrating heart injuries cause wounds in the cardiac chambers. Most of them are due to gunshot or stabbing by knives. Screwdriver is an uncommon weapon. Authors report a case of stab wound by screwdriver, treated at cardiovascular center in Dakar. This is a 16-year-old boy who experienced physical aggression. He was assaulted with a screwdriver and had stab wound on the anterior wall of the chest. Physical examination showed a screwdriver penetrating the sternum bone over a right angle. He had a mild pericardial blood effusion and a right ventricle wound 5 mm in diameter with transection of the right coronary vein. The screwdriver was removed without cardiopulmonary bypass (CPB) and the ventricle wound repaired by direct suture of stitches reinforced with Teflon pledgets. The right coronary artery was ligated. Postoperative period was free of events. Screwdriver is uncommonly used as a weapon. It is a dangerous device because of its rigid structure and narrow tip. PMID:25945263

  20. Benchmark field study of deep neutron penetration

    NASA Astrophysics Data System (ADS)

    Morgan, J. F.; Sale, K.; Gold, R.; Roberts, J. H.; Preston, C. C.

    1991-06-01

    A unique benchmark neutron field has been established at the Lawrence Livermore National Laboratory (LLNL) to study deep penetration neutron transport. At LLNL, a tandem accelerator is used to generate a monoenergetic neutron source that permits investigation of deep neutron penetration under conditions that are virtually ideal to model, namely the transport of mono-energetic neutrons through a single material in a simple geometry. General features of the Lawrence Tandem (LATAN) benchmark field are described with emphasis on neutron source characteristics and room return background. The single material chosen for the first benchmark, LATAN-1, is a steel representative of Light Water Reactor (LWR) Pressure Vessels (PV). Also included is a brief description of the Little Boy replica, a critical reactor assembly designed to mimic the radiation doses from the atomic bomb dropped on Hiroshima, and its us in neutron spectrometry.

  1. Benchmark field study of deep neutron penetration

    SciTech Connect

    Morgan, J.F.; Sale, K. ); Gold, R.; Roberts, J.H.; Preston, C.C. )

    1991-06-10

    A unique benchmark neutron field has been established at the Lawrence Livermore National Laboratory (LLNL) to study deep penetration neutron transport. At LLNL, a tandem accelerator is used to generate a monoenergetic neutron source that permits investigation of deep neutron penetration under conditions that are virtually ideal to model, namely the transport of mono-energetic neutrons through a single material in a simple geometry. General features of the Lawrence Tandem (LATAN) benchmark field are described with emphasis on neutron source characteristics and room return background. The single material chosen for the first benchmark, LATAN-1, is a steel representative of Light Water Reactor (LWR) Pressure Vessels (PV). Also included is a brief description of the Little Boy replica, a critical reactor assembly designed to mimic the radiation doses from the atomic bomb dropped on Hiroshima, and its us in neutron spectrometry. 18 refs.

  2. Transorbital Penetrating Intracranial Injury by a Chopstick

    PubMed Central

    Shin, Tae-Hee; Kim, Jong-Hoon; Kwak, Kyung-Woo

    2012-01-01

    A 38-year-old man fell from a chair with a chopstick in his hand. The chopstick penetrated his left eye. He noticed pain, swelling, and numbness around his left eye. On physical examination, a linear wound was noted at the medial aspect of the left eyelid. Noncontrast computed tomography (CT) study showed a linear hypodense structure extending from the medial aspect of the left orbit to the occipital bone, suggesting a foreign body. This foreign body was hyperdense relative to normal parenchyma. From a CT scan with 3-dimensional reconstruction, the foreign body was found to be passing through the optic canal into the cranium. The clear plastic chopstick was withdrawn without difficulty. The patient was discharged home 3 weeks after his surgery. A treatment plan for a transorbital penetrating injury should be determined by a multidisciplinary team, with input from neurosurgeons and ophthalmologists. PMID:23133735

  3. Weld penetration and defect control. Final report

    SciTech Connect

    Chin, B.A.

    1992-05-15

    Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.

  4. Market penetration of new energy technologies

    SciTech Connect

    Packey, D.J.

    1993-02-01

    This report examines the characteristics, advantages, disadvantages, and, for some, the mathematical formulas of forecasting methods that can be used to forecast the market penetration of renewable energy technologies. Among the methods studied are subjective estimation, market surveys, historical analogy models, cost models, diffusion models, time-series models, and econometric models. Some of these forecasting methods are more effective than others at different developmental stages of new technologies.

  5. Corrosion Inhibitors as Penetrant Dyes for Radiography

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    2003-01-01

    Liquid/vapor-phase corrosion inhibitors (LVCIs) have been found to be additionally useful as penetrant dyes for neutron radiography (and perhaps also x-radiography). Enhancement of radiographic contrasts by use of LVCIs can reveal cracks, corrosion, and other defects that may be undetectable by ultrasonic inspection, that are hidden from direct optical inspection, and/or that are difficult or impossible to detect in radiographs made without dyes.

  6. Jet initiation and penetration of explosives

    SciTech Connect

    Mader, C.L.; Pimbley, G.H.

    1983-01-01

    The two-dimensional Eulerian hydrodynamic code 2DE, with the shock initiation of heterogeneous explosive burn model called Forest Fire, is used to model numerically the interaction of jets of steel, copper, tantalum, aluminum, and water with steel, water, and explosive targets. The calculated and experimental critical condition for propagating detonation may be described by the Held V/sup 2/d expression (jet velocity squared times the jet diameter). In PBX 9502, jets initiate an overdriven detonation smaller than the critical diameter, which either fails or enlarges to greater than the critical diameter while the overdriven detonation decays to the C-J state. In PBX 9404, the jet initiates a detonation that propagates only if it is maintained by the jet for an interval sufficient to establish a stable curved detonation front. The calculated penetration velocities into explosives, initiated by a low-velocity jet, are significantly less than for non-reactive solids of the same density. The detonation products near the jet tip have a pressure higher than that of nonreactive explosives, and thus show the jet penetration. At high jet velocities, the calculated penetration velocities are similar for reactive and inert targets.

  7. Jet initiation and penetration of explosives

    SciTech Connect

    Mader, C.L.; Pimbley, G.H.

    1983-01-01

    The two-dimensional Eulerian hydrodynamic code 2DE with the shock initiation of heterogeneous explosive burn model called Forest Fire, is used to model numerically the interaction of jets of steel, copper, tantalum, aluminum, and water with steel, water, and explosive targets. The calculated and experimental critical condition for propagating detonation may be described by the Held V/sup 2/d expression (jet velocity squared times the jet diameter). In PBX 9502, jets initiate an overdriven detonation smaller than the critical diameter, which either fails or enlarges to greater than the critical diameter while the overdriven detonation decays to the C-J state. In PBX 9404, the jet initiates a detonation that propagates only if it is maintained by the jet for an interval sufficient to establish a stable curved detonation front. The calculated penetration velocities into explosives, initiated by a low-velocity jet, are significantly less than for non-reactive solids of the same density. The detonation products near the jet tip have a pressure higher than that of nonreactive explosives, and thus slow the jet penetration. At high jet velocities, the calculated penetration velocities are similar for reactive and inert targets. 8 references, 17 figures, 1 table.

  8. Essential Fatty Acids as Transdermal Penetration Enhancers.

    PubMed

    van Zyl, Lindi; du Preez, Jan; Gerber, Minja; du Plessis, Jeanetta; Viljoen, Joe

    2016-01-01

    The aim of this study was to investigate the effect of different penetration enhancers, containing essential fatty acids (EFAs), on the transdermal delivery of flurbiprofen. Evening primrose oil (EPO), vitamin F, and Pheroid technology all contain fatty acids and were compared using a cream-based formulation. This selection was to ascertain whether EFAs solely, or EFAs in a Pheroid delivery system, would have a significant increase in the transdermal delivery of a compound. Membrane release studies were performed, and the results indicated the following rank order for flurbiprofen release from the different formulations: vitamin F > control > EPO > Pheroid. Topical skin delivery results indicated that flurbiprofen was present in the stratum corneum-epidermis and the epidermis-dermis. The average percentage flurbiprofen diffused to the receptor phase (representing human blood) indicated that the EPO formulation showed the highest average percentage diffused. The Pheroid formulation delivered the lowest concentration with a statistical significant difference (p < 0.05) compared with the control formulation (containing 1% flurbiprofen and no penetration enhancers). The control formulation presented the highest average flux, with the EPO formulation following the closest. It could, thus, be concluded that EPO is the most favorable chemical penetration enhancer when used in this formulation. PMID:26852854

  9. Deep penetration of light into biotissue

    NASA Astrophysics Data System (ADS)

    Bearden, Edward D.; Wilson, James D.; Zharov, Vladimir P.; Lowery, Curtis L.

    2001-07-01

    The results of a study of deep (several centimeters) light penetration into biological tissue are presented in order to estimate its significance to potentially photosensitive structures and processes including the fetal eyes. In order to accomplish this goal, samples of various tissues (fat, muscle, and uterus) from surgical patients and autopsies were examined with a double integrating sphere arrangement to determine their optical properties. The results were implemented in a Monte Carlo modeling program. Next, optical fiber probes were inserted into the uterus and abdominal wall of patients undergoing laparoscopic procedures. The fibers were couples to a photomultiplier tube with intervening filters allowing measurements of light penetration at various wavelengths. To determine the feasibility of stimulation in utero, a xenon lamp and waveguide were used to transilluminate the abdomen of several labor patients. Light in the range of 630 to 670 nm where the eye sensitivity and penetration depth are well matched, will likely provide the best chance of visual stimulation. Fetal heart rate, fetal movement, and fetal magnetoencephalography (SQUID) and electroencephalography (EEG) were observed in different studies to determine if stimulation has occurred. Since internal organs and the fetus are completely dark adapted, the amount of light required to simulate in our opinion could be on the order of 10(superscript -8 Watts.

  10. Drawdown and stream depletion produced by pumping in the vicinity of a partially penetrating stream

    USGS Publications Warehouse

    Butler, J.J., Jr.; Zlotnik, V.A.; Tsou, M.-S.

    2001-01-01

    Commonly used analytical approaches for estimation of pumping-induced drawdown and stream depletion are based on a series of idealistic assumptions about the stream-aquifer system. A new solution has been developed for estimation of drawdown and stream depletion under conditions that are more representative of those in natural systems (finite width stream of shallow penetration adjoining an aquifer of limited lateral extent). This solution shows that the conventional assumption of a fully penetrating stream will lead to a significant overestimation of stream depletion (> 100 %) in many practical applications. The degree of overestimation will depend on the value of the stream leakance parameter and the distance from the pumping well to the stream. Although leakance will increase with stream width, a very wide stream will not necessarily be well represented by a model of a fully penetrating stream. The impact of lateral boundaries depends upon the distance from the pumping well to the stream and the stream leakance parameter. In most cases, aquifer width must be on the order of hundreds of stream widths before the assumption of a laterally infinite aquifer is appropriate for stream-depletion calculations. An important assumption underlying this solution is that stream-channel penetration is negligible relative to aquifer thickness. However, an approximate extension to the case of nonnegligible penetration provides reasonable results for the range of relative penetrations found in most natural systems (up to 85%). Since this solution allows consideration of a much wider range of conditions than existing analytical approaches, it could prove to be a valuable new tool for water management design and water rights adjudication purposes.

  11. The role of testosterone in trichloroethylene penetration in vitro

    SciTech Connect

    McCormick, K.; Abdel-Rahman, M.S. )

    1991-02-01

    Sex differences are known to exist in the metabolism and bioavailability of trichloroethylene (TCE). This study revealed that dermal penetration of ({sup 14}C)TCE in vitro was twofold greater in untreated female than in untreated male Sprague-Dawley rats. Since testosterone has been shown to mediate a wide variety of sex differences, its role in dermal penetration of ({sup 14}C)TCE was investigated. Penetration was measured by using an in vitro evaporation-penetration cell with a 10-hour collection period. Depriving male rats of testosterone (by castration) resulted in increased values for total penetration, area under the curve (AUC), and penetration slopes compared to those found in the female control group. Administration of testosterone to female animals produced values for total penetration, AUC, and penetration slopes significantly lower than those of the female control group.

  12. Scientists Spot 'Switch' That Helps Sperm Penetrate Egg

    MedlinePlus

    ... fullstory_158021.html Scientists Spot 'Switch' That Helps Sperm Penetrate Egg Finding could eventually lead to unisex ... switch" that triggers the sudden tail whip that sperm use to penetrate and fertilize an egg has ...

  13. Mucus-penetrating nanoparticles for vaginal and gastrointestinal drug delivery

    NASA Astrophysics Data System (ADS)

    Ensign-Hodges, Laura

    A method that could provide more uniform and longer-lasting drug delivery to mucosal surfaces holds the potential to greatly improve the effectiveness of prophylactic and therapeutic approaches for numerous diseases and conditions, including sexually transmitted infections and inflammatory bowel disease. However, the body's natural defenses, including adhesive, rapidly cleared mucus linings coating nearly all entry points to the body not covered by skin, has limited the effectiveness of drug and gene delivery by nanoscale delivery systems. Here, we investigate the use of muco-inert mucus-penetrating nanoparticles (MPP) for improving vaginal and gastrointestinal drug delivery. Conventional hydrophobic nanoparticles strongly adhere to mucus, facilitating rapid clearance from the body. Here, we demonstrate that mucoadhesive polystyrene nanoparticles (conventional nanoparticles, CP) become mucus-penetrating in human cervicovaginal mucus (CVM) after pretreatment with sufficient concentrations of Pluronic F127. Importantly, the diffusion rate of large MPP did not change in F127 pretreated CVM, implying there is no affect on the native pore structure of CVM. Additionally, there was no increase in inflammatory cytokine release in the vaginal tract of mice after daily application of 1% F127 for one week. Importantly, HSV virus remains adherent in F127-pretreated CVM. Mucosal epithelia use osmotic gradients for fluid absorption and secretion. We hypothesized that hypotonically-induced fluid uptake could be advantageous for rapidly delivering drugs through mucus to the vaginal epithelium. We evaluated hypotonic formulations for delivering water-soluble drugs and for drug delivery with MPP. Hypotonic formulations markedly increased the rate at which drugs and MPP reached the epithelial surface. Additionally, hypotonic formulations greatly enhanced drug and MPP delivery to the entire epithelial surface, including deep into the vaginal folds (rugae) that isotonic formulations

  14. Mucus-penetrating nanoparticles for vaginal and gastrointestinal drug delivery

    NASA Astrophysics Data System (ADS)

    Ensign-Hodges, Laura

    A method that could provide more uniform and longer-lasting drug delivery to mucosal surfaces holds the potential to greatly improve the effectiveness of prophylactic and therapeutic approaches for numerous diseases and conditions, including sexually transmitted infections and inflammatory bowel disease. However, the body's natural defenses, including adhesive, rapidly cleared mucus linings coating nearly all entry points to the body not covered by skin, has limited the effectiveness of drug and gene delivery by nanoscale delivery systems. Here, we investigate the use of muco-inert mucus-penetrating nanoparticles (MPP) for improving vaginal and gastrointestinal drug delivery. Conventional hydrophobic nanoparticles strongly adhere to mucus, facilitating rapid clearance from the body. Here, we demonstrate that mucoadhesive polystyrene nanoparticles (conventional nanoparticles, CP) become mucus-penetrating in human cervicovaginal mucus (CVM) after pretreatment with sufficient concentrations of Pluronic F127. Importantly, the diffusion rate of large MPP did not change in F127 pretreated CVM, implying there is no affect on the native pore structure of CVM. Additionally, there was no increase in inflammatory cytokine release in the vaginal tract of mice after daily application of 1% F127 for one week. Importantly, HSV virus remains adherent in F127-pretreated CVM. Mucosal epithelia use osmotic gradients for fluid absorption and secretion. We hypothesized that hypotonically-induced fluid uptake could be advantageous for rapidly delivering drugs through mucus to the vaginal epithelium. We evaluated hypotonic formulations for delivering water-soluble drugs and for drug delivery with MPP. Hypotonic formulations markedly increased the rate at which drugs and MPP reached the epithelial surface. Additionally, hypotonic formulations greatly enhanced drug and MPP delivery to the entire epithelial surface, including deep into the vaginal folds (rugae) that isotonic formulations

  15. Capillary Penetration into Inclined Circular Glass Tubes.

    PubMed

    Trabi, Christophe L; Ouali, F Fouzia; McHale, Glen; Javed, Haadi; Morris, Robert H; Newton, Michael I

    2016-02-01

    The spontaneous penetration of a wetting liquid into a vertical tube against the force of gravity and the imbibition of the same liquid into a horizontal tube (or channel) are both driven by capillary forces and described by the same fundamental equations. However, there have been few experimental studies of the transition from one orientation to the other. We report systematic measurements of capillary penetration of polydimethylsiloxane oils of viscosities 9.6, 19.2, and 48.0 mPa·s into glass capillary tubes. We first report the effect of tube radii R between 140 and 675 μm on the dynamics of spontaneous imbibition. We show that the data can be fitted using the exact numerical solution to the governing equations and that these are similar to fits using the analytical viscogravitational approximation. However, larger diameter tubes show a rate of penetration slower than expected using an equilibrium contact angle and the known value of liquid viscosity. To account for the slowness, an increase in viscosity by a factor (η/ρ)(scaling) is needed. We show full agreement with theory requires the ratio R/κ(-1) ∼ 0.1 or less, where κ(-1) is the capillary length. In addition, we propose an experimental method that enables the determination of the dynamic contact angle during imbibition, which gives values that agree with the literature values. We then report measurements of dynamic penetration into the tubes of R = 190 and 650 μm for a range of inclination angles to the horizontal, φ, from 5 to 90°. We show that capillary penetration can still be fitted using the viscogravitational solution, rather than the Bosanquet solution which describes imbibition without gravity, even for inclination angles as low as 10°. Moreover, at these low angles, the effect of the tube radius is found to diminish and this appears to relate to an effective capillary length, κ(-1)(φ) = (γ(LV)/ρg sin φ)(1/2). PMID:26738739

  16. The measurement of creep in ultrahigh molecular weight polyethylene: a comparison of conventional versus highly cross-linked polyethylene.

    PubMed

    Estok, Daniel M; Bragdon, Charles R; Plank, Gordon R; Huang, Anna; Muratoglu, Orhun K; Harris, William H

    2005-02-01

    Quantification of creep of highly cross-linked polyethylene would enable separation of creep from wear when evaluating femoral head penetration into polyethylene. We compared creep magnitude of a highly cross-linked versus conventional polyethylene in the laboratory. Twelve acetabular liners of each material were tested, 6 of which had a 32-mm inner diameter (ID) and 6 had 28-mm ID. Creep was measured using coordinate measuring machines during loading at 2 Hz without motion to 4 million cycles. Penetration into 32-mm ID conventional liners reached 97 microm versus 107 microm for highly cross-linked material, not significant. Penetration into 28-mm conventional liners was 132 microm versus 155 microm for highly cross-linked material (P = .017). Ninety percent of the creep had occurred by 2.5 million cycles. PMID:15902864

  17. NULL convention floating point multiplier.

    PubMed

    Albert, Anitha Juliette; Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069

  18. NULL Convention Floating Point Multiplier

    PubMed Central

    Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069

  19. Verifying Removal Of Red Penetrant Dye From Inspected Welds

    NASA Technical Reports Server (NTRS)

    Torkelson, Jan R.

    1996-01-01

    Clean surface assured for more sensitive inspection with fluorescent penetrant dye. Simple procedure devised to ensure visible (red) penetrant dye used to identify flaws in welded surface completely removed from surface. Consists in applying reversible penetrant developer to surface to be inspected.

  20. Skin accumulation and penetration of a hydrophilic compound by a novel gemini surfactant, sodium dilauramidoglutamide lysine.

    PubMed

    Hikima, Tomohiro; Tamura, Yoshinaga; Yamawaki, Yukio; Yamamoto, Masashi; Tojo, Kakuji

    2013-02-25

    We investigated a novel peptide-based gemini amphiphilic compound, sodium dilauramidoglutamide lysine (DLGL), as a chemical enhancer for the skin penetration of l-ascorbic acid 2-glucoside (AAG). A three-dimensional cultured human skin product, TESTSKIN™ LSE-high (LSE-high), was used as a skin model. The penetration flux of AAG with DLGL and that obtained with sodium lauramidoglutamide (LG) as a conventional surfactant across LSE-high were increased by 12.56 and 69.29 times compared to the control, respectively. The ratio of AAG amount with DLGL in the skin (21.78% total dose) was significantly increased (p<0.05) compared to the control (7.23%) and to the AAG amount with LG (8.13%). The AAG amounts in receptor were 1.06% (control), 3.19% (+DLGL) and 21.00% (+LG). Thus, DLGL preserved AAG in skin, resulting in enhanced AAG penetration flux. However, LG might create the pathways through the skin. We conclude that DLGL is a gemini surfactant that accumulates a hydrophilic compound in skin and enhances the penetration flux. DLGL may therefore be a novel addition agent for skin local therapy. PMID:23291444

  1. Minimum velocity necessary for nonconventional projectiles to penetrate the eye: an experimental study using pig eyes.

    PubMed

    Marshall, John W; Dahlstrom, Dean B; Powley, Kramer D

    2011-06-01

    To satisfy the Criminal Code of Canada's definition of a firearm, a barreled weapon must be capable of causing serious bodily injury or death to a person. Canadian courts have accepted the forensically established criteria of "penetration or rupture of an eye" as serious bodily injury. The minimal velocity of nonconventional ammunition required to penetrate the eye including airsoft projectiles has yet to be established. To establish minimal threshold requirements for eye penetration, empirical tests were conducted using a variety of airsoft projectiles. Using the data obtained from these tests, and previous research using "air gun" projectiles, an "energy density" parameter was calculated for the minimum penetration threshold of an eye. Airsoft guns capable of achieving velocities in excess of 99 m/s (325 ft/s) using conventional 6-mm airsoft ammunition will satisfy the forensically established criteria of "serious bodily injury." The energy density parameter for typical 6-mm plastic airsoft projectiles is 4.3 to 4.8 J/cm². This calculation also encompasses 4.5-mm steel BBs. PMID:21263287

  2. Scalable Method to Produce Biodegradable Nanoparticles that Rapidly Penetrate Human Mucus

    PubMed Central

    Xu, Qingguo; Boylan, Nicholas J.; Cai, Shutian; Miao, Bolong; Patel, Himatkumar; Hanes, Justin

    2013-01-01

    Mucus typically traps and rapidly removes foreign particles from the airways, gastrointestinal tract, nasopharynx, female reproductive tract and the surface of the eye. Nanoparticles capable of rapid penetration through mucus can potentially avoid rapid clearance, and open significant opportunities for controlled drug delivery at mucosal surfaces. Here, we report an industrially scalable emulsification method to produce biodegradable mucus-penetrating particles (MPP). The emulsification of diblock copolymers of poly(lactic-co-glycolic acid) and polyethylene glycol (PLGA-PEG) using low molecular weight (MW) emulsifiers forms dense brush PEG coatings on nanoparticles that allow rapid nanoparticle penetration through fresh undiluted human mucus. In comparison, conventional high MW emulsifiers, such as polyvinyl alcohol (PVA), interrupts the PEG coating on nanoparticles, resulting in their immobilization in mucus owing to adhesive interactions with mucus mesh elements. PLGA-PEG nanoparticles with a wide range of PEG MW (1, 2, 5, and 10 kDa), prepared by the emulsification method using low MW emulsifiers, all rapidly penetrated mucus. A range of drugs, from hydrophobic small molecules to hydrohilic large biologics, can be efficiently loaded into biodegradable MPP using the method described. This readily scalable method should facilitate the production of MPP products for mucosal drug delivery, as well as potentially longer-circulating particles following intravenous administration. PMID:23751567

  3. Market penetration scenarios for fuel cell vehicles

    SciTech Connect

    Thomas, C.E.; James, B.D.; Lomax, F.D. Jr.

    1997-12-31

    Fuel cell vehicles may create the first mass market for hydrogen as an energy carrier. Directed Technologies, Inc., working with the US Department of Energy hydrogen systems analysis team, has developed a time-dependent computer market penetration model. This model estimates the number of fuel cell vehicles that would be purchased over time as a function of their cost and the cost of hydrogen relative to the costs of competing vehicles and fuels. The model then calculates the return on investment for fuel cell vehicle manufacturers and hydrogen fuel suppliers. The model also projects the benefit/cost ratio for government--the ratio of societal benefits such as reduced oil consumption, reduced urban air pollution and reduced greenhouse gas emissions to the government cost for assisting the development of hydrogen energy and fuel cell vehicle technologies. The purpose of this model is to assist industry and government in choosing the best investment strategies to achieve significant return on investment and to maximize benefit/cost ratios. The model can illustrate trends and highlight the sensitivity of market penetration to various parameters such as fuel cell efficiency, cost, weight, and hydrogen cost. It can also illustrate the potential benefits of successful R and D and early demonstration projects. Results will be shown comparing the market penetration and return on investment estimates for direct hydrogen fuel cell vehicles compared to fuel cell vehicles with onboard fuel processors including methanol steam reformers and gasoline partial oxidation systems. Other alternative fueled vehicles including natural gas hybrids, direct injection diesels and hydrogen-powered internal combustion hybrid vehicles will also be analyzed.

  4. Azithromycin pharmacokinetics and penetration to lymph.

    PubMed

    Bergan, T; Jørgensen, N P; Olszewski, W; Zhang, Y

    1992-01-01

    The study of pharmacokinetics of azithromycin and penetration to peripheral human lymph was carried out in 14 healthy male volunteers taking 1 g orally after overnight fasting. Samples were analyzed by microbiological assay. The mean peak concentrations were 0.82 +/- 0.23 mg/l after 1.7 +/- 0.5 h in serum and 0.22 +/- 0.07 mg/l after 3.1 h in lymph. Nine of the 14 subjects showed a second and lower serum peak indicating the existence of enterohepatic circulation. The total areas under the serum concentrations curves (AUCs) till infinity were 7.9 +/- 3.1 mg. h/l compared to 4.4 +/- 1.2 mg.h/l in lymph. The mean lymph AUC was 68.1 +/- 20.7% of the serum AUC indicating a penetration ratio of 0.68. However, the actual amounts penetrating the tissues were much higher than this ratio suggests. Thus, after 6 h 81% of the drug was within the tissue compartment and after 120 h, 63% of the azithromycin was still present in the tissue compartment. The urinary recovery of azithromycin was 14.7 +/- 7.7% during the first 48 h. The serum curves and lymph curves displayed a distinctly slower phase of elimination after 12 h. The mean serum half-life was 5.4 +/- 3.4 h during the first 12 h (after the peak), whereas the value was 44.2 +/- 10.1 h during the interval 12-120 h. The corresponding half-life values for the peripheral lymph were 5.4 +/- 2.2 h and 50.8 +/- 11.6 h. Azithromycin possesses key pharmacokinetic properties that are prerequisites for a convenient once-daily dosage schedule which may improve patient compliance. PMID:1336891

  5. Theme: FFA Conventions and Contests.

    ERIC Educational Resources Information Center

    Garten, Stacy A.; And Others

    1985-01-01

    Theme articles focus on FFA (Future Farmers of America) conventions and contests. They examine FFA as an extracurricular versus intracurricular activity, keeping competition in perspective, contests as student motivators, how a sponsor views FFA, improving the teaching of leadership, benefits of FFA participation, the needs of disadvantaged and…

  6. Hydrogen storage: beyond conventional methods.

    PubMed

    Dalebrook, Andrew F; Gan, Weijia; Grasemann, Martin; Moret, Séverine; Laurenczy, Gábor

    2013-10-01

    The efficient storage of hydrogen is one of three major hurdles towards a potential hydrogen economy. This report begins with conventional storage methods for hydrogen and broadly covers new technology, ranging from physical media involving solid adsorbents, to chemical materials including metal hydrides, ammonia borane and liquid precursors such as alcohols and formic acid. PMID:23964360

  7. Ability Measurement: Conventional or Adaptive?

    ERIC Educational Resources Information Center

    Weiss, David J.; Betz, Nancy E.

    Research to date on adaptive (sequential, branched, individualized, tailored, programmed, response-contingent) ability testing is reviewed and summarized, following a brief review of problems inherent in conventional individual and group approaches to ability measurement. Research reviewed includes empirical, simulation and theoretical studies of…

  8. Effect of Liquid Penetrant Sensitivity on Probability of Detection

    NASA Technical Reports Server (NTRS)

    Parker, Bradford H.

    2008-01-01

    The objective of the task is to investigate the effect of liquid penetrant sensitivity level on probability of crack detection (POD). NASA-STD-5009 currently requires the use of only sensitivity level 4 liquid penetrants. This requirement is based on the fact that the data generated in the NTIAC Nondestructive Evaluation (NDE) Capabilities Data Book was produced using only sensitivity level 4 penetrants. Many NDE contractors supporting NASA Centers routinely use sensitivity level 3 penetrants. Because of the new NASA-STD-5009 requirement, these contractors will have to either shift to sensitivity level 4 penetrants or perform formal POD demonstration tests to qualify their existing process.

  9. Surface penetrators for planetary exploration: Science rationale and development program

    NASA Technical Reports Server (NTRS)

    Murphy, J. P.; Reynolds, R. T.; Blanchard, M. B.; Clanton, U. S.

    1981-01-01

    Work on penetrators for planetary exploration is summarized. In particular, potential missions, including those to Mars, Mercury, the Galilean satellites, comets, and asteroids are described. A baseline penetrator design for the Mars mission is included, as well as potential instruments and their status in development. Penetration tests in soft soil and basalt to study material eroded from the penetrator; changes in the structure, composition, and physical properties of the impacted soil; seismic coupling; and penetrator deflection caused by impacting rocks, are described. Results of subsystem studies and tests are given for design of entry decelerators, high-g components, thermal control, data acquisition, and umbilical cable deployment.

  10. A novel approach to penetrator calculations

    SciTech Connect

    Budge, K.G.

    1998-08-01

    The author presents a novel method for calculating the penetration of soft targets by hard projectiles by using a combination of ALE and contact surface techniques. This method allows the bifurcation in the softer material (at the point of the projectile) to be represented without sacrificing the Lagrangian representation of either the harder material or the contact interface. A series of calculations using this method show good agreement with the experimental data of Forrestal et al. This method may prove useful for a range of semi-fluid/structure interactions with friction, including simulations of manufacturing processes.

  11. Radar penetration in the Amazonian rain forest

    NASA Technical Reports Server (NTRS)

    Pereiradacunha, Roberto; Ford, John

    1986-01-01

    Radar return from vegetation covered terrains is due to three components: the scattering resulting from the top surface of the vegetation canopy (surface scattering); the scattering which occurs within the vegetation layer (volume scattering); and the scattering which takes place at the surface below the vegetation canopy (ground scattering). Through the studies of selected areas in the Amazon Region a case is presented where most of the radar returns observed in radar imagery results from the scattering at the surface below vegetation layer (ground scattering). Thus, radar penetration occurred.

  12. Filter Enhances Fluorescent-Penetrant-Inspecting Borescope

    NASA Technical Reports Server (NTRS)

    Molina, Orlando G.

    1990-01-01

    Slip-on eyepiece for commercial ultraviolet-light borescope reduces both amount of short-wave ultraviolet light that reaches viewer's eye and apparent intensity of unwanted reflections of white light from surfaces undergoing inspection. Fits on stock eyepiece of borescope, which illuminates surface inspected with intense ultraviolet light. Surface, which is treated with fluorescent dye, emits bright-green visible light wherever dye penetrates - in cracks and voids. Eyepiece contains deep-yellow Wratten 15 (G) filter, which attenuates unwanted light strongly but passes yellow-green fluorescence so defects seen clearly.

  13. Cephradine (Velosef) penetration of mandibular bone.

    PubMed

    Middlehurst, R J; Rood, J P

    1990-04-01

    The concentration of cephradine in serum and mandibular bone was assayed in 28 patients undergoing 3rd molar surgery following a single 1 g intravenous injection. Serum and cortical bone samples taken simultaneously, contained mean cephradine concentrations of 42.11 micrograms/ml and 2.61 micrograms/g respectively. These results, when compared with those reported for other bony sites including the femoral head and knee, show a reduced bone penetration with a bone-to-serum ratio of approximately 0.06:1. PMID:2111359

  14. Space station integrated wall design and penetration damage control. Task 3: Theoretical analysis of penetration mechanics

    NASA Technical Reports Server (NTRS)

    Bjorkman, M. D.; Geiger, J. D.; Wilhelm, E. E.

    1987-01-01

    The efforts to provide a penetration code called PEN4 version 10 is documented for calculation of projectile and target states for the impact of 2024-T3 aluminum, R sub B 90 1018 steel projectiles and icy meteoroids onto 2024-T3 aluminum plates at impact velocities from 0 to 16 km/s. PEN4 determines whether a plate is perforated by calculating the state of fragmentation of projectile and first plate. Depth of penetration into the second to n sup th plate by fragments resulting from first plate perforation is determined by multiple cratering. The results from applications are given.

  15. Depth-Penetrating Luminescence Thermography of Thermal- Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Eldridge, Jeffrey

    2005-01-01

    transparent or at least translucent. Conventional thermographic phosphors are not suitable because they are most efficiently excited by ultraviolet light, which does not penetrate thermal- barrier coating materials. (Typical thermal-barrier coating materials include or consist of various formulations of yttria-stabilized zirconia.) Only a small fraction of phosphor candidates have significant excitation at wavelengths long enough (>500 nm) for sufficient penetration of thermal-barrier coatings. One suitable phosphor material . yttria doped with europium (Y2O3:Eu) . has a minor excitation peak at 532 nm and an emission peak at 611 nm. In experiments, this material was incorporated beneath a 100-microns-thick thermal-barrier coating and subjected to excitation and measurement by the luminescence-decay-time technique. These experiments were found to yield reliable temperature values up to 1,100 C. At the time of reporting the information for this article, a search for suitable phosphors other than (Y2O3:Eu) was continuing.

  16. Microbial Penetration through Nutrient-Saturated Berea Sandstone.

    PubMed

    Jenneman, G E; McInerney, M J; Knapp, R M

    1985-08-01

    Penetration times and penetration rates for a motile Bacillus strain growing in nutrient-saturated Berea sandstone cores were determined. The rate of penetration was essentially independent of permeabilities above 100 mdarcys and rapidly declined for permeabilities below 100 mdarcys. It was found that these penetration rates could be grouped into two statistically distinct classes consisting of rates for permeabilities above 100 mdarcys and rates for those below 100 mdarcys. Instantaneous penetration rates were found to be zero order with respect to core length for cores with permeabilities above 100 mdarcys and first order with respect to core length for cores with permeabilities below 100 mdarcys. The maximum observed penetration rate was 0.47 cm . h, and the slowest was 0.06 cm . h; however, these rates may be underestimates of the true penetration rate, since the observed rates included the time required for growth in the flask as well as the core. The relationship of penetration time to the square of the length of the core suggested that cells penetrated high-permeability cores as a band and low-permeability cores in a diffuse fashion. The motile Enterobacter aerogenes strain penetrated Berea sandstone cores three to eight times faster than did the nonmotile Klebsiella pneumoniae strain when cores of comparable length and permeability were used. A penetration mechanism based entirely on motility predicted penetration times that were in agreement with the observed penetration times for motile strains. The fact that nonmotile strains penetrated the cores suggested that filamentous or unrestricted growth, or both, may also be important. PMID:16346858

  17. Microbial Penetration through Nutrient-Saturated Berea Sandstone

    PubMed Central

    Jenneman, Gary E.; McInerney, Michael J.; Knapp, Roy M.

    1985-01-01

    Penetration times and penetration rates for a motile Bacillus strain growing in nutrient-saturated Berea sandstone cores were determined. The rate of penetration was essentially independent of permeabilities above 100 mdarcys and rapidly declined for permeabilities below 100 mdarcys. It was found that these penetration rates could be grouped into two statistically distinct classes consisting of rates for permeabilities above 100 mdarcys and rates for those below 100 mdarcys. Instantaneous penetration rates were found to be zero order with respect to core length for cores with permeabilities above 100 mdarcys and first order with respect to core length for cores with permeabilities below 100 mdarcys. The maximum observed penetration rate was 0.47 cm · h−1, and the slowest was 0.06 cm · h−1; however, these rates may be underestimates of the true penetration rate, since the observed rates included the time required for growth in the flask as well as the core. The relationship of penetration time to the square of the length of the core suggested that cells penetrated high-permeability cores as a band and low-permeability cores in a diffuse fashion. The motile Enterobacter aerogenes strain penetrated Berea sandstone cores three to eight times faster than did the nonmotile Klebsiella pneumoniae strain when cores of comparable length and permeability were used. A penetration mechanism based entirely on motility predicted penetration times that were in agreement with the observed penetration times for motile strains. The fact that nonmotile strains penetrated the cores suggested that filamentous or unrestricted growth, or both, may also be important. PMID:16346858

  18. Ground penetrating radar for asparagus detection

    NASA Astrophysics Data System (ADS)

    Seyfried, Daniel; Schoebel, Joerg

    2016-03-01

    Ground penetrating radar is a promising technique for detection of buried objects. Recently, radar has more and more been identified to provide benefits for a plurality of applications, where it can increase efficiency of operation. One of these fields is the industrial automatic harvesting process of asparagus, which is performed so far by cutting the soil ridge at a certain height including all the asparagus spears and subsequently sieving the latter out of the soil. However, the height where the soil is cut is a critical parameter, since a wrong value leads to either damage of the roots of the asparagus plants or to a reduced crop yield as a consequence of too much biomass remaining in the soil. In this paper we present a new approach which utilizes ground penetrating radar for non-invasive sensing in order to obtain information on the optimal height for cutting the soil. Hence, asparagus spears of maximal length can be obtained, while keeping the roots at the same time undamaged. We describe our radar system as well as the subsequent digital signal processing steps utilized for extracting the information required from the recorded radar data, which then can be fed into some harvesting unit for setting up the optimal cutting height.

  19. [Delayed brain abscess after penetrating transorbital injury].

    PubMed

    Hiraishi, Tetsuya; Tomikawa, Masaru; Kobayashi, Tsutomu; Kawaguchi, Tadashi

    2007-05-01

    We report a case of brain abscess caused by a penetrating head injury that occurred 9 years earlier. A 14-year-old girl presenting with fever, headache, and stiff neck was admitted to our hospital. She was diagnosed with aseptic meningitis and treated conservatively. Seven days after admission she became stuporous and showed left hemiparesis. Computed tomography (CT) revealed two ring-enhancing masses with perifocal edema in the right frontal lobe. We diagnosed brain abscess and performed right fronto-temporal decompressive craniectomy and stereotactic aspiration, followed by systemic antibiotic therapy. Post-surgery bone window CT revealed a well-defined, low-density foreign body passing from the left orbita to the right frontal lobe through the ethmoid sinus. We learned that the patient had been struck with a plastic chopstick in the left medial eyelid at the age of 5 years. No particular symptoms developed during the following 9 years. After the cerebral edema had diminished over the next 10 days, a second surgery was performed to remove the residual chopstick, repair the fistula at the base of the skull, and perform cranioplasty. The patient was discharged with only slight hyposmia after a 4-week course of antibiotics. This case showed that it is necessary to remove a residual foreign body and to close the dural fistula if there is a possibility of recurrent central nervous system infection. When a child presents with brain abscess, previous penetrating head injury should be considered. PMID:17491344

  20. Asbestos penetration test system for clothing materials

    SciTech Connect

    Bradley, O.D.; Stampfer, J.F.; Sandoval, A.N.; Heath, C.A.; Cooper, M.H.

    1997-04-01

    For hazardous work such as asbestos abatement, there is a need to assess protective clothing fabrics and seam constructions to assure an adequate barrier against hazardous material. The penetration of aerosols through fabrics usually is measured by challenging fabric samples with an aerosol stream at a constant specified airflow. To produce the specified airflow, pressure differentials across the samples often are higher than exist in a work environment. This higher airflow results in higher aerosol velocities through the fabric and, possibly, measured penetration values not representative of those actually experienced in the field. The objective of the reported work was to develop a test method that does not require these higher airflows. The authors have designed and fabricated a new system that tests fabric samples under a low, constant, specified pressure differential across the samples. This differential is adjustable from tenths of a mm Water Gauge (hundredths of an in WG) to over 25-mm WG (1-in WG). The system operates at a pressure slightly lower than its surroundings. Although designed primarily for asbestos, the system is equally applicable to the testing of other aerosols by changing the aerosol generator and detector. Through simple modification of the sample holders, the test apparatus would be capable of evaluating seam and closure constructions.

  1. EFFECTS OF PENETRATIVE CONVECTION ON SOLAR DYNAMO

    SciTech Connect

    Masada, Youhei; Yamada, Kohei; Kageyama, Akira

    2013-11-20

    Spherical solar dynamo simulations are performed. A self-consistent, fully compressible magnetohydrodynamic system with a stably stratified layer below the convective envelope is numerically solved with a newly developed simulation code based on the Yin-Yang grid. The effects of penetrative convection are studied by comparing two models with and without the stable layer. The differential rotation profile in both models is reasonably solar-like with equatorial acceleration. When considering the penetrative convection, a tachocline-like shear layer is developed and maintained beneath the convection zone without assuming any forcing. While the turbulent magnetic field becomes predominant in the region where the convective motion is vigorous, mean-field components are preferentially organized in the region where the convective motion is less vigorous. Particularly in the stable layer, the strong, large-scale field with a dipole symmetry is spontaneously built up. The polarity reversal of the mean-field component takes place globally and synchronously throughout the system regardless of the presence of the stable layer. Our results suggest that the stably stratified layer is a key component for organizing the large-scale strong magnetic field, but is not essential for the polarity reversal.

  2. High Penetration Photovoltaic Case Study Report

    SciTech Connect

    Bank, J.; Mather, B.; Keller, J.; Coddington, M.

    2013-01-01

    Technical concerns with integrating higher penetrations of photovoltaic (PV) systems include grid stability, voltage regulation, power quality (voltage rise, sags, flicker, and frequency fluctuations), and protection and coordination. The current utility grid was designed to accommodate power flows from the central generation source to the transmission system and eventually to the distribution feeders. At the distribution level, the system was designed to carry power from the substation toward the load. Renewable distributed generation, particularly solar PV, provides power at the distribution level challenging this classical paradigm. As these resources become more commonplace the nature of the distribution network and its operation is changing to handle power flow in both directions. This report is focused on large PV installations in which penetration is significantly greater than 15% of maximum daytime feeder load. These case studies are intended to demonstrate success stories with integration of large PV plants at the distribution level as well as some of the solutions used by the utility to ensure safe, reliable operation of both the PV system and the distribution network.

  3. Penetrator Coring Apparatus for Cometary Surfaces

    NASA Technical Reports Server (NTRS)

    Braun, David F.; Heinrich, Michael; Ai, Huirong Anita; Ahrens, Thomas J.

    2004-01-01

    Touch and go impact coring is an attractive technique for sampling cometary nuclei and asteroidal surface on account of the uncertain strength properties and low surface gravities of these objects. Initial coring experiments in low temperature (approx. 153K polycrystalline ice) and porous rock demonstrate that simultaneous with impact coring, measurements of both the penetration strength and constraints on the frictional properties of surface materials can be obtained upon core penetration and core sample extraction. The method of sampling an asteroid, to be deployed, on the now launched MUSES-C mission, employs a small gun device that fires into the asteroid and the resulted impact ejecta is collected for return to Earth. This technique is well suited for initial sampling in a very low gravity environment and deployment depends little on asteroid surface mechanical properties. Since both asteroids and comets are believed to have altered surface properties a simple sampling apparatus that preserves stratigraphic information, such as impact coring is an attractive alternate to impact ejecta collection.

  4. Penetration of projectiles into granular targets

    NASA Astrophysics Data System (ADS)

    Ruiz-Suárez, J. C.

    2013-06-01

    Energetic collisions of subatomic particles with fixed or moving targets have been very valuable to penetrate into the mysteries of nature. But the mysteries are quite intriguing when projectiles and targets are macroscopically immense. We know that countless debris wandering in space impacted (and still do) large asteroids, moons and planets; and that millions of craters on their surfaces are traces of such collisions. By classifying and studying the morphology of such craters, geologists and astrophysicists obtain important clues to understand the origin and evolution of the Solar System. This review surveys knowledge about crater phenomena in the planetary science context, avoiding detailed descriptions already found in excellent papers on the subject. Then, it examines the most important results reported in the literature related to impact and penetration phenomena in granular targets obtained by doing simple experiments. The main goal is to discern whether both schools, one that takes into account the right ingredients (planetary bodies and very high energies) but cannot physically reproduce the collisions, and the other that easily carries out the collisions but uses laboratory ingredients (small projectiles and low energies), can arrive at a synergistic intersection point.

  5. Simulation of Hypervelocity Penetration in Limestone

    SciTech Connect

    Antoun, T; Glenn, L; Walton, O; Goldstein, P; Lomov, I; Liu, B

    2005-05-31

    A parameter study was performed to examine the (shock) damage obtained with long-rod and spherical mono-material penetrators impacting two varieties of limestone. In all cases, the impacts were assumed to be normal to the plane of the rock and at zero angle of attack (in the case of the rods). Impact velocities ranged to 15 km/s but most calculations were performed at 4 and 6 km/s and the penetrator mass was fixed at 1000 kg. For unlined underground structures, incipient damage was defined to occur when the peak stress, {sigma}{sub pk}, exceeds 1 kb (100 MPa) and the applied impulse per unit area, I{sub pk}, exceeds 1 ktap (1 kb-{micro}s). Severe damage was assumed to occur when {sigma}{sub pk} exceeds 1 kb and I{sub pk} exceeds 1000 ktaps. Using the latter definition it was found that severe damage in hard, non-porous limestone with spherical impactors extended to a depth of 9 m on-axis for an impact velocity of 4 km/s and 12 m at 6 km/s. Cylinders with length-to-diameter (L/D) ratio of 8.75 achieved depth to severe damage of 23 m and 40 m, respectively under the same conditions. For a limestone medium with 2% initial gas porosity, the latter numbers were reduced to 12 m and 18 m.

  6. Penetration of projectiles into granular targets.

    PubMed

    Ruiz-Suárez, J C

    2013-06-01

    Energetic collisions of subatomic particles with fixed or moving targets have been very valuable to penetrate into the mysteries of nature. But the mysteries are quite intriguing when projectiles and targets are macroscopically immense. We know that countless debris wandering in space impacted (and still do) large asteroids, moons and planets; and that millions of craters on their surfaces are traces of such collisions. By classifying and studying the morphology of such craters, geologists and astrophysicists obtain important clues to understand the origin and evolution of the Solar System. This review surveys knowledge about crater phenomena in the planetary science context, avoiding detailed descriptions already found in excellent papers on the subject. Then, it examines the most important results reported in the literature related to impact and penetration phenomena in granular targets obtained by doing simple experiments. The main goal is to discern whether both schools, one that takes into account the right ingredients (planetary bodies and very high energies) but cannot physically reproduce the collisions, and the other that easily carries out the collisions but uses laboratory ingredients (small projectiles and low energies), can arrive at a synergistic intersection point. PMID:23660625

  7. More on the penetration of yawed rods

    NASA Astrophysics Data System (ADS)

    Rosenberg, Z.; Dekel, E.; Ashuach, Y.

    2006-08-01

    One of the most complex processes, in the field of terminal ballistics, is that of yawed impact of long rods. In spite of many experimental observations, and some analytical modeling, a clear picture of this issue is still lacking. In order to gain some insight into the operating mechanisms, we developed a simple engineering model which considers the yawed rod as a series of small disks. We then define the effective length and diameter of the rod by considering those disks which are going to hit the initial crater which is opened by the impact. We also performed a series of 3D numerical simulations with various L/D tungsten alloy rods impacting a steel target, at yaws in the full range of 0-90^circ. We analyzed the results of these simulations in terms of the normalized penetration (P/D), where D is the rod diameter, and looked for systematic trends in the results for the various rods. The agreement between our model predictions and both experimental data and simulation results is quite good. Based on this agreement we can highlight some new features of the penetration process of yawed rods.

  8. Singularity of the London Penetration Depth at Quantum Critical Points in Superconductors

    NASA Astrophysics Data System (ADS)

    Chowdhury, Debanjan; Swingle, Brian; Berg, Erez; Sachdev, Subir

    2013-10-01

    We present a general theory of the singularity in the London penetration depth at symmetry-breaking and topological quantum critical points within a superconducting phase. While the critical exponents and ratios of amplitudes on the two sides of the transition are universal, an overall sign depends upon the interplay between the critical theory and the underlying Fermi surface. We determine these features for critical points to spin density wave and nematic ordering, and for a topological transition between a superconductor with Z2 fractionalization and a conventional superconductor. We note implications for recent measurements of the London penetration depth in BaFe2(As1-xPx)2 [K. Hashimoto , Science 336, 1554 (2012)SCIEAS0036-807510.1126/science.1219821].

  9. Impact of short-term storage on frequency response under increasing wind penetration

    NASA Astrophysics Data System (ADS)

    Krishnan, Venkat; Das, Trishna; McCalley, James D.

    2014-07-01

    In this paper, the effort is to study the impact of short-term storage technology in stabilizing the frequency response under increasing wind penetration. The frequency response is studied using Automatic Generation Control (AGC) module, and is quantified in terms of Control Performance Standards (CPS). The single area IEEE Reliability Test System (RTS) was chosen, and battery storage was integrated within the AGC. The battery proved to reduce the frequency deviations and provide good CPS scores with higher penetrations of wind. The results also discuss the ability of the short term storage to benefit the system by reducing the hourly regulation deployment and the cycling undergone by conventional units, by dint of their fast response; and sheds light on the economic implications of their benefits.

  10. Error field penetration and locking to the backward wave

    NASA Astrophysics Data System (ADS)

    Finn, John; Cole, Andrew; Brennan, Dylan

    2015-11-01

    Error field penetration involves driving a stable tearing mode in a rotating toroidal plasma. In this paper it is shown that locking for modes with real frequencies ωr differ from conventional results. The reconnected flux for modes with frequencies +/-ωr in the plasma frame is maximized when the frequency of the stable backward mode (-ωr) in the lab frame is zero, i.e. when v =ωr / k . Notably, the locking torque is exactly zero at v =ωr / k , with a pronounced peak at just higher rotation, leading to a locked state with plasma velocity just above ωr / k . Real frequencies are known to occur due to the Glasser effect for modes in the resistive-inertial (RI) regime. This therefore leads to locking of the plasma velocity to just above v =ωr / k . Also, similar real frequencies can occur in the visco-resistive (VR) regime with pressure, and the locking torque is similar to the RI result. Real frequencies occur due to diamagnetic effects in other tearing mode regimes and also show this effect. Nonlinear effects on the mode amplitude and torque for weakly stable modes or large error fields are discussed. We discuss the possibility of applying external fields of different helicities to drive sheared flows.

  11. Air Quality Improvements of Increased Integration of Renewables: Solar Photovoltaics Penetration Scenarios

    NASA Astrophysics Data System (ADS)

    Duran, P.; Holloway, T.; Brinkman, G.; Denholm, P.; Littlefield, C. M.

    2011-12-01

    Solar photovoltaics (PV) are an attractive technology because they can be locally deployed and tend to yield high production during periods of peak electric demand. These characteristics can reduce the need for conventional large-scale electricity generation, thereby reducing emissions of criteria air pollutants (CAPs) and improving ambient air quality with regard to such pollutants as nitrogen oxides, sulfur oxides and fine particulates. Such effects depend on the local climate, time-of-day emissions, available solar resources, the structure of the electric grid, and existing electricity production among other factors. This study examines the air quality impacts of distributed PV across the United States Eastern Interconnection. In order to accurately model the air quality impact of distributed PV in space and time, we used the National Renewable Energy Lab's (NREL) Regional Energy Deployment System (ReEDS) model to form three unique PV penetration scenarios in which new PV construction is distributed spatially based upon economic drivers and natural solar resources. Those scenarios are 2006 Eastern Interconnection business as usual, 10% PV penetration, and 20% PV penetration. With the GridView (ABB, Inc) dispatch model, we used historical load data from 2006 to model electricity production and distribution for each of the three scenarios. Solar PV electric output was estimated using historical weather data from 2006. To bridge the gap between dispatch and air quality modeling, we will create emission profiles for electricity generating units (EGUs) in the Eastern Interconnection from historical Continuous Emissions Monitoring System (CEMS) data. Via those emissions profiles, we will create hourly emission data for EGUs in the Eastern Interconnect for each scenario during 2006. Those data will be incorporated in the Community Multi-scale Air Quality (CMAQ) model using the Sparse Matrix Operator Kernel Emissions (SMOKE) model. Initial results indicate that PV

  12. The Craft of Writing: Breaking Conventions

    ERIC Educational Resources Information Center

    Paraskevas, Cornelia

    2004-01-01

    The rhetorical power of punctuation conventions as well as the effect of violating those conventions should be explained to the students. The craft in conventions can be found anywhere and all good writers use it in their work.

  13. Penetrating injuries to the thoracic great vessels.

    PubMed

    Demetriades, D

    1997-01-01

    Penetrating injuries to the thoracic great vessels have been diagnosed with increased frequency because of the escalating use of automatic weapons. The overall incidence is 5.3% of gunshot wounds and 2% of stab wounds to the chest. Most of these patients reach the hospital dead or in severe shock. The overall mortality of thoracic aortic injuries is higher than 90% and in subclavian vascular injuries higher than 65%. In the prehospital phase, the "scoop and run" policy offers the best chances of survival and no attempts should be made for any form of stabilization. Investigations should be reserved only for fairly stable patients. Angiography, color flow Doppler, and transesophageal echocardiography may be useful in selected cases. Patients in cardiac arrest or imminent cardiac arrest may benefit from an emergency room thoracotomy. The surgical approach to specific thoracic great vessels is described. PMID:9271743

  14. Deep optical penetration dynamics in photobending.

    PubMed

    Corbett, Daniel; Xuan, Chen; Warner, Mark

    2015-07-01

    We model both the photostationary state and dynamics of an illuminated, photosensitive, glassy liquid crystalline sheet. To illustrate the interplay between local tilt θ of the sheet, effective incident intensity, curvature, and dynamics, we adopt the simplest variation of local incident light intensity with angle, that is, cosθ. The tilt in the stationary state never overshoots the vertical, but maximum curvature could be seen in the middle of the sheet for intense light. In dynamics, overshoot and self-eclipsing arise, revealing how important moving fronts of light penetration are. Eclipsing is qualitatively as in the experiments of Yu et al. [Y. Yu, M. Nakano, and T. Ikeda, Nature (London) 425, 145 (2003)]. PMID:26274300

  15. Obstacle penetrating dynamic radar imaging system

    DOEpatents

    Romero, Carlos E.; Zumstein, James E.; Chang, John T.; Leach, Jr.. Richard R.

    2006-12-12

    An obstacle penetrating dynamic radar imaging system for the detection, tracking, and imaging of an individual, animal, or object comprising a multiplicity of low power ultra wideband radar units that produce a set of return radar signals from the individual, animal, or object, and a processing system for said set of return radar signals for detection, tracking, and imaging of the individual, animal, or object. The system provides a radar video system for detecting and tracking an individual, animal, or object by producing a set of return radar signals from the individual, animal, or object with a multiplicity of low power ultra wideband radar units, and processing said set of return radar signals for detecting and tracking of the individual, animal, or object.

  16. Delineate subsurface structures with ground penetrating radar

    SciTech Connect

    Wyatt, D.E.; Hu, L.Z.; Ramaswamy, M.; Sexton, B.G.

    1992-10-01

    High resolution ground penetrating radar (GPR) surveys were conducted at the Savannah River Site in South Carolina in late 1991 to demonstrate the radar techniques in imaging shallow utility and soil structures. Targets of interest at two selected sites, designated as H- and D-areas, were a buried backfilled trench, buried drums, geologic stratas, and water table. Multiple offset 2-D and single offset 3-D survey methods were used to acquire high resolution radar data. This digital data was processed using standard seismic processing software to enhance signal quality and improve resolution. Finally, using a graphics workstation, the 3D data was interpreted. In addition, a small 3D survey was acquired in The Woodlands, Texas, with very dense spatial sampling. This data set adequately demonstrated the potential of this technology in imaging subsurface features.

  17. Delineate subsurface structures with ground penetrating radar

    SciTech Connect

    Wyatt, D.E. ); Hu, L.Z. ); Ramaswamy, M. ); Sexton, B.G. )

    1992-01-01

    High resolution ground penetrating radar (GPR) surveys were conducted at the Savannah River Site in South Carolina in late 1991 to demonstrate the radar techniques in imaging shallow utility and soil structures. Targets of interest at two selected sites, designated as H- and D-areas, were a buried backfilled trench, buried drums, geologic stratas, and water table. Multiple offset 2-D and single offset 3-D survey methods were used to acquire high resolution radar data. This digital data was processed using standard seismic processing software to enhance signal quality and improve resolution. Finally, using a graphics workstation, the 3D data was interpreted. In addition, a small 3D survey was acquired in The Woodlands, Texas, with very dense spatial sampling. This data set adequately demonstrated the potential of this technology in imaging subsurface features.

  18. Automatic control of oscillatory penetration apparatus

    DOEpatents

    Lucon, Peter A

    2015-01-06

    A system and method for controlling an oscillatory penetration apparatus. An embodiment is a system and method for controlling a sonic drill having a displacement and an operating range and operating at a phase difference, said sonic drill comprising a push-pull piston and eccentrics, said method comprising: operating the push-pull piston at an initial push-pull force while the eccentrics are operated at a plurality of different operating frequencies within the operating range of the sonic drill and measuring the displacement at each operating frequency; determining an efficient operating frequency for the material being drilled and operating the eccentrics at said efficient operating frequency; determining the phase difference at which the sonic drill is operating; and if the phase difference is not substantially equal to minus ninety degrees, operating the push-pull piston at another push-pull force.

  19. Fluorescent Penetrant INSPECTION—CLEANING Study Update

    NASA Astrophysics Data System (ADS)

    Eisenmann, D.; Brasche, L.

    2009-03-01

    Fluorescent penetrant inspection (FPI) is widely used in the aviation industry and other industries for surface-breaking crack detection. As with all inspection methods, adherence to the process parameters is critical to the successful detection of defects. There is variety of lubricants and surface coatings used in the aviation industry which must be removed prior to FPI. Before the FPI process begins, components are cleaned using a variety of cleaning methods which are selected based on the alloy and the soil types which must be removed. It is also important that the cleaning process not adversely affect the FPI process. From the first three phases of this project it has been found that a hot water rinse can aid in the detection process when using this nondestructive method.

  20. Deep optical penetration dynamics in photobending

    NASA Astrophysics Data System (ADS)

    Corbett, Daniel; Xuan, Chen; Warner, Mark

    2015-07-01

    We model both the photostationary state and dynamics of an illuminated, photosensitive, glassy liquid crystalline sheet. To illustrate the interplay between local tilt θ of the sheet, effective incident intensity, curvature, and dynamics, we adopt the simplest variation of local incident light intensity with angle, that is, cosθ . The tilt in the stationary state never overshoots the vertical, but maximum curvature could be seen in the middle of the sheet for intense light. In dynamics, overshoot and self-eclipsing arise, revealing how important moving fronts of light penetration are. Eclipsing is qualitatively as in the experiments of Yu et al. [Y. Yu, M. Nakano, and T. Ikeda, Nature (London) 425, 145 (2003), 10.1038/425145a].

  1. First principles cable braid electromagnetic penetration model

    SciTech Connect

    Warne, Larry Kevin; Langston, William L.; Basilio, Lorena I.; Johnson, William A.

    2016-01-01

    The model for penetration of a wire braid is rigorously formulated. Integral formulas are developed from energy principles for both self and transfer immittances in terms of potentials for the fields. The detailed boundary value problem for the wire braid is also set up in a very efficient manner; the braid wires act as sources for the potentials in the form of a sequence of line multi-poles with unknown coefficients that are determined by means of conditions arising from the wire surface boundary conditions. Approximations are introduced to relate the local properties of the braid wires to a simplified infinite periodic planar geometry. Furthermore, this is used to treat nonuniform coaxial geometries including eccentric interior coaxial arrangements and an exterior ground plane.

  2. Wide band stepped frequency ground penetrating radar

    DOEpatents

    Bashforth, Michael B.; Gardner, Duane; Patrick, Douglas; Lewallen, Tricia A.; Nammath, Sharyn R.; Painter, Kelly D.; Vadnais, Kenneth G.

    1996-01-01

    A wide band ground penetrating radar system (10) embodying a method wherein a series of radio frequency signals (60) is produced by a single radio frequency source (16) and provided to a transmit antenna (26) for transmission to a target (54) and reflection therefrom to a receive antenna (28). A phase modulator (18) modulates those portion of the radio frequency signals (62) to be transmitted and the reflected modulated signal (62) is combined in a mixer (34) with the original radio frequency signal (60) to produce a resultant signal (53) which is demodulated to produce a series of direct current voltage signals (66) the envelope of which forms a cosine wave shaped plot (68) which is processed by a Fast Fourier Transform unit 44 into frequency domain data (70) wherein the position of a preponderant frequency is indicative of distance to the target (54) and magnitude is indicative of the signature of the target (54).

  3. Wide band stepped frequency ground penetrating radar

    DOEpatents

    Bashforth, M.B.; Gardner, D.; Patrick, D.; Lewallen, T.A.; Nammath, S.R.; Painter, K.D.; Vadnais, K.G.

    1996-03-12

    A wide band ground penetrating radar system is described embodying a method wherein a series of radio frequency signals is produced by a single radio frequency source and provided to a transmit antenna for transmission to a target and reflection therefrom to a receive antenna. A phase modulator modulates those portions of the radio frequency signals to be transmitted and the reflected modulated signal is combined in a mixer with the original radio frequency signal to produce a resultant signal which is demodulated to produce a series of direct current voltage signals, the envelope of which forms a cosine wave shaped plot which is processed by a Fast Fourier Transform Unit 44 into frequency domain data wherein the position of a preponderant frequency is indicative of distance to the target and magnitude is indicative of the signature of the target. 6 figs.

  4. First principles cable braid electromagnetic penetration model

    DOE PAGESBeta

    Warne, Larry Kevin; Langston, William L.; Basilio, Lorena I.; Johnson, William A.

    2016-01-01

    The model for penetration of a wire braid is rigorously formulated. Integral formulas are developed from energy principles for both self and transfer immittances in terms of potentials for the fields. The detailed boundary value problem for the wire braid is also set up in a very efficient manner; the braid wires act as sources for the potentials in the form of a sequence of line multi-poles with unknown coefficients that are determined by means of conditions arising from the wire surface boundary conditions. Approximations are introduced to relate the local properties of the braid wires to a simplified infinitemore » periodic planar geometry. Furthermore, this is used to treat nonuniform coaxial geometries including eccentric interior coaxial arrangements and an exterior ground plane.« less

  5. Cell Penetrating Peptides and Cationic Antibacterial Peptides

    PubMed Central

    Rodriguez Plaza, Jonathan G.; Morales-Nava, Rosmarbel; Diener, Christian; Schreiber, Gabriele; Gonzalez, Zyanya D.; Lara Ortiz, Maria Teresa; Ortega Blake, Ivan; Pantoja, Omar; Volkmer, Rudolf; Klipp, Edda; Herrmann, Andreas; Del Rio, Gabriel

    2014-01-01

    Cell penetrating peptides (CPP) and cationic antibacterial peptides (CAP) have similar physicochemical properties and yet it is not understood how such similar peptides display different activities. To address this question, we used Iztli peptide 1 (IP-1) because it has both CPP and CAP activities. Combining experimental and computational modeling of the internalization of IP-1, we show it is not internalized by receptor-mediated endocytosis, yet it permeates into many different cell types, including fungi and human cells. We also show that IP-1 makes pores in the presence of high electrical potential at the membrane, such as those found in bacteria and mitochondria. These results provide the basis to understand the functional redundancy of CPPs and CAPs. PMID:24706763

  6. Pathway Controlled Penetration (PcP)

    SciTech Connect

    Knight, Earl E.; Rougier, Esteban; Zubelewicz, Aleksander

    2012-08-29

    The technical approach employs advanced computational simulation tools to demonstrate how current assets can destroy RWK-RFI-12-0001's HDBT, a tunnel complex with two portals built into the base of a granite mountain. The granite over layer is assumed to be 60 meters thick over both portals and 80 meters over the facility's mission space. Key S&T is the completed development of a highly innovative viscoplastic fracture material model, 3D parallel gas-fracture capabilities into FDEM, and a stochastic handling of the material properties. Phase I - Develop and validate code simulation tools: (1) develop, incorporate and validate AZ-Frac material model for granite; and (2) Develop and incorporate gas-driven-fracture modeling into LANL's FDEM MUNROU code; (3) Develop and incorporate stochastic features into FDEM modeling. Phase II - Conduct PcP analysis on above HDBT: (1) Acquire HDBT design data, develop simulation model; and (2) Evaluate and select most promising defeat alternative. Phase III - Deliver code, train Service target analysts, and conduct simulations against real world HDBTs. PcP uses advanced computer simulations to enhance HDBT functional defeat efforts. Newly developed material models that account for fractural energy coupled with the finite discrete element methodology (FDEM) will provide targeting packages that will create penetration avenues for current or future lethality options. This novel computational approach requires full 3D geologic and structure characterization as well as significant high performance computing capabilities. The goal is to distinctively alter the targeting paradigm by leveraging critical DoD assets along with insitu geologic strata. In other words, assets will utilize underground rock structure to their benefit by creating rubbilization zones that will allow pathway controlled penetration.

  7. Novel penetrating cations for targeting mitochondria.

    PubMed

    Chernyak, Boris V; Antonenko, Yuri N; Domnina, Lidia V; Ivanova, Olga Yu; Lyamzaev, Konstantin G; Pustovidko, Antonina V; Rokitskaya, Tatiana I; Severina, Inna I; Simonyan, Ruben A; Trendeleva, Tatiana A; Zvyagilskaya, Renata A

    2013-01-01

    Novel penetrating cations were used for the design of mitochondria-targeted compounds and tested in model lipid membranes, in isolated mitochondria and in living human cells in culture. Rhodamine-19, berberine and palmatine were conjugated by aliphatic linkers with plastoquinone possessing antioxidant activity. These conjugates (SkQR1,SkQBerb, SkQPalm) and their analogs lacking plastoquinol moiety (C12R1,C10Berb and C10Palm) penetrated bilayer phospholipid membrane in their cationic forms and accumulated in isolated mitochondria or in mitochondria of living cells due to membrane potential negative inside. Reduced forms of SkQR1, SkQBerb and SkQPalm inhibited lipid peroxidation in isolated mitochondria at nanomolar concentrations. In human fibroblasts SkQR1, SkQBerb and SkQPalm prevented fragmentation of mitochondria and apoptosis induced by hydrogen peroxide. SkQR1 was effective at subnanomolar concentrations while SkQberb, SkQPalm and SkQ1 (prototypic conjugate of plastoquinone with dodecyltriphenylphosphonium) were effective at 10-times higher concentrations. The aliphatic conjugates of berberine and palmatine (as well as the conjugates of triphenylphosphonium) induced proton transport mediated by free fatty acids (FA) both in the model and mitochondrial membrane. In mitochondria this process was facilitated by the adenine nucleotide carrier. In contrast to the other cationic conjugates, SkQR1 and C12R1 induced FA-independent proton conductivity due to protonation/deprotonation of the rhodamine residue. This property in combination with the antioxidant activity probably makes rhodamine conjugates highly effective in protection against oxidative stress. The novel cationic conjugates described here are promising candidates for drugs against various pathologies and aging as mitochondria-targeted antioxidants and selective mild uncouplers. PMID:23092317

  8. Evaluation of penetration depth of 2% chlorhexidine digluconate into root dentinal tubules using confocal laser scanning microscope

    PubMed Central

    Latha, Jothi; Velmurugan, Natanasabapathy

    2015-01-01

    Objectives This study evaluated the penetration depth of 2% chlorhexidine digluconate (CHX) into root dentinal tubules and the influence of passive ultrasonic irrigation (PUI) using a confocal laser scanning microscope (CLSM). Materials and Methods Twenty freshly extracted anterior teeth were decoronated and instrumented using Mtwo rotary files up to size 40, 4% taper. The samples were randomly divided into two groups (n = 10), that is, conventional syringe irrigation (CSI) and PUI. CHX was mixed with Rhodamine B dye and was used as the final irrigant. The teeth were sectioned at coronal, middle and apical levels and viewed under CLSM to record the penetration depth of CHX. The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests. Results The mean penetration depths of 2% CHX in coronal, middle and apical thirds were 138 µm, 80 µm and 44 µm in CSI group, respectively, whereas the mean penetration depths were 209 µm, 138 µm and 72 µm respectively in PUI group. Statistically significant difference was present between CSI group and PUI group at all three levels (p < 0.01 for coronal third and p < 0.001 for middle and apical thirds). On intragroup analysis, both groups showed statistically significant difference among three levels (p < 0.001). Conclusions Penetration depth of 2% CHX into root dentinal tubules is deeper in coronal third when compared to middle and apical third. PUI aided in deeper penetration of 2% CHX into dentinal tubules when compared to conventional syringe irrigation at all three levels. PMID:25984477

  9. Modeling of Oblique Penetration into Geologic Targets Using Cavity Expansion Penetrator Loading with Target free-Surface Effects

    SciTech Connect

    Jung, Joe; Longcope, Donald B.; Tabbara, Mazen R.

    1999-05-03

    A procedure has been developed to represent the loading on a penetrator and its motion during oblique penetration into geologic media. The penetrator is modeled with the explicit dynamics, finite element computer program PRONTO 3D and the coupled pressure on the penetrator is given in a new loading option based on a separate cavity expansion (CE) solution that accounts for the pressure-reduction from a nearby target free surface. The free-surface influ- ence distance is selected in a predictive manner by considering the pressure to expand a spherical cavity in a finite radius sphere of the target material. The CE/PRONTO 3D procedure allows a detailed description of the penetrator for predicting shock environments or structural failure dur- ing the entire penetration event and is sufficiently rapid to be used in design optimization. It has been evaluated by comparing its results with data from two field tests of a full-scale penetrator into frozen soil at an impact angles of 49.6 and 52.5 degrees from the horizontal. The measured penetrator rotations were 24 and 22 degrees, respectively. In the simulation, the rotation was21 degrees and predominately resulted from the pressure reduction of the free surface. Good agree- ment was also found for the penetration depth and axial and lateral acceleration at two locations in the penetrator.

  10. The full penetration hole as a stochastic process: controlling penetration depth in keyhole laser-welding processes

    NASA Astrophysics Data System (ADS)

    Blug, A.; Abt, F.; Nicolosi, L.; Heider, A.; Weber, R.; Carl, D.; Höfler, H.; Tetzlaff, R.

    2012-07-01

    Although laser-welding processes are frequently used in industrial production the quality control of these processes is not satisfactory yet. Until recently, the "full penetration hole" was presumed as an image feature which appears when the keyhole opens at the bottom of the work piece. Therefore it was used as an indicator for full penetration only. We used a novel camera based on "cellular neural networks" which enables measurements at frame rates up to 14 kHz. The results show that the occurrence of the full penetration hole can be described as a stochastic process. The probability to observe it increases near the full penetration state. In overlap joints, a very similar image feature appears when the penetration depth reaches the gap between the sheets. This stochastic process is exploited by a closed-loop system which controls penetration depth near the bottom of the work piece ("full penetration") or near the gap in overlap joints ("partial penetration"). It guides the welding process at the minimum laser power necessary for the required penetration depth. As a result, defects like spatters are reduced considerably and the penetration depth becomes independent of process drifts such as feeding rate or pollution on protection glasses.

  11. Stability of Full Penetration, Flat Position Weld Pools

    NASA Technical Reports Server (NTRS)

    Nunes, Arthur C., Jr.; Coan, Al. B.

    1999-01-01

    The dynamics of the dropthrough distance of a full penetration, flat position weld pool is described. Close to incipient root side penetration the dropthrough is metastable, so that a small drop in power can cause a loss of penetration if not followed soon enough by a compensating rise in power. The SPA (Soft Plasma Arc) process with higher pressure on top of the weld pool loses penetration more quickly than the GTA (Gas Tungsten Arc) process. 2195 aluminum-lithium alloy with a lower surface tension loses penetration more quickly than 2219 aluminum alloy. An instance of loss of penetration of a SPA weld in 2195 aluminum-lithium alloy is discussed in the light of the model.

  12. Spatial resolution of MFM measurements of penetration depth

    NASA Astrophysics Data System (ADS)

    Spanton, Eric; Luan, Lan; Kirtley, John; Moler, Kathryn

    2012-02-01

    The penetration depth and its temperature dependence are key ways to characterize superconductors. Measurements of the local Meissner response of a superconductor can determine the local penetration depth. To quantify the spatial resolution of such measurements, we seek to characterize the point spread function of magnetic force microscope (MFM) measurements of the penetration depth both numerically and experimentally. Modeling various geometries of MFM tips (pyramid, dipole, and long thin cylinder) in the presence of various geometries of spatial variation in the penetration depth (point variation, columnar defects, and planar defects or twin boundaries) shows the importance of the MFM tip geometry to achieving both excellent spatial resolution and quantitatively interpretable results. We compare these models to experimental data on pnictides and cuprates to set upper limits on the sub-micron-scale variation of the penetration depth. These results demonstrate both the feasibility and the technical challenges of submicron penetration depth mapping.

  13. Attempts to increase penetration of photoacoustic system using LED array light souce

    NASA Astrophysics Data System (ADS)

    Agano, Toshitaka; Sato, Naoto; Nakatsuka, Hitoshi; Kitagawa, Kazuo; Hanaoka, Takamitsu; Morisono, Koji; Shigeta, Yusuke

    2015-03-01

    When we consider the needle visualization in the field of point of care by utilizing the photoacoustic imaging system, and using the conventional solid state laser light source, the issue arises such as device size and not a green system due to the high power consumption. Therefore, we aimed at an environmentally friendly and compact system with low power consumption by using a NIR-LED array light source. The intensity of NIR-LED light is weak, but, by averaging photoacoustic signals with multiple pulse, we have improved S/N of the photoacoustic signal. As a result, we've achieved penetration depth of 30mm.

  14. Study of Comet Nucleus Gamma-Ray Spectrometer Penetration System

    NASA Technical Reports Server (NTRS)

    Adams, G. L.; Amundsen, R. J.; Beardsley, R. W.; Cash, R. H.; Clark, B. C.; Knight, T. C. D.; Martin, J. P.; Monti, P.; Outteridge, D. A.; Plaster, W. D.

    1986-01-01

    A penetrator system has been suggested as an approach for making in situ measurements of the composition and physical properties of the nucleus of a comet. This study has examined in detail the feasibility of implementing the penetrator concept. The penetrator system and mission designs have been developed and iterated in sufficient detail to provide a high level of confidence that the concept can be implemented within the constraints of the Mariner Mark 2 spacecraft.

  15. 10 CFR 429.23 - Conventional cooking tops, conventional ovens, microwave ovens.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Conventional cooking tops, conventional ovens, microwave... Conventional cooking tops, conventional ovens, microwave ovens. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to conventional cooking tops, conventional...

  16. 10 CFR 429.23 - Conventional cooking tops, conventional ovens, microwave ovens.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Conventional cooking tops, conventional ovens, microwave... Conventional cooking tops, conventional ovens, microwave ovens. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to conventional cooking tops, conventional...

  17. 10 CFR 429.23 - Conventional cooking tops, conventional ovens, microwave ovens.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Conventional cooking tops, conventional ovens, microwave... Conventional cooking tops, conventional ovens, microwave ovens. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to conventional cooking tops, conventional...

  18. The next generation cell-penetrating peptide and carbon dot conjugated nano-liposome for transdermal delivery of curcumin.

    PubMed

    Patra, Santanu; Roy, Ekta; Madhuri, Rashmi; Sharma, Prashant K

    2016-03-01

    To overcome the problems associated with conventional liposomes in transdermal drug delivery like limited penetration ability and poor stability, in this article we report a new generation of cell penetrating peptide polyarginine containing nano-liposomes conjugated with carbon dots. The newly synthesized, cost-effective liposomic precursors were used for the fabrication of liposomes. The resulting liposomes have a bilayer structure like that of conventional liposomes with much smaller size, higher stability, and high penetration ability. The nano-liposomes show high stability at room temperature for three months without any change in size or encapsulation efficiency. The incorporation of carbon dots also opens up their application in fluorescence cell imaging studies, which is very well supported by the fluorescence microscopic analysis of the liposome skin penetration. The as-prepared nano-liposomes do not show any cytotoxicity for MCF-7 cells, even at high concentrations; however, when drug loaded liposomes are applied, they can kill the cancer cells with a high rate. The synthesized nano-liposomes have the potential to be used as an efficient, stable, biocompatible nanocarrier for transdermal drug delivery. PMID:26631310

  19. Conventional and Non-Conventional Drosophila Toll Signaling

    PubMed Central

    Lindsay, Scott A.; Wasserman, Steven A.

    2013-01-01

    The discovery of Toll in Drosophila and of the remarkable conservation in pathway composition and organization catalyzed a transformation in our understanding of innate immune recognition and response. At the center of that picture is a cascade of interactions in which specific microbial cues activate Toll receptors, which then transmit signals driving transcription factor nuclear localization and activity. Experiments gave substance to the vision of pattern recognition receptors, linked phenomena in development, gene regulation, and immunity into a coherent whole, and revealed a rich set of variations for identifying non-self and responding effectively. More recently, research in Drosophila has illuminated the positive and negative regulation of Toll activation, the organization of signaling events at and beneath membranes, the sorting of information flow, and the existence of non-conventional signaling via Toll-related receptors. Here, we provide an overview of the Toll pathway of flies and highlight these ongoing realms of research. PMID:23632253

  20. Dilution Confusion: Conventions for Defining a Dilution

    ERIC Educational Resources Information Center

    Fishel, Laurence A.

    2010-01-01

    Two conventions for preparing dilutions are used in clinical laboratories. The first convention defines an "a:b" dilution as "a" volumes of solution A plus "b" volumes of solution B. The second convention defines an "a:b" dilution as "a" volumes of solution A diluted into a final volume of "b". Use of the incorrect dilution convention could affect…

  1. Characterization of nuclear reactor containment penetrations. Preliminary report

    SciTech Connect

    Bump, T.R.; Seidensticker, R.W.; Shackelford, M.A.; Gambhir, V.K.; McLennan, G.L.

    1984-06-01

    This report summarizes the survey work conducted by Argonne National Laboratory on the design and details of major penetrations in 22 nuclear power plants. The survey includes all containment types and materials in current use. It also includes details of all types of penetrations (except for electrical penetration assemblies and valves) and the seals and gaskets used in them. The report provides a test matrix for testing major penetrations and for testing seals and gaskets in order to evaluate their leakage potential under severe accident conditions.

  2. Analysis of thermal performance of penetrated multi-layer insulation

    NASA Technical Reports Server (NTRS)

    Foster, Winfred A., Jr.; Jenkins, Rhonald M.; Yoo, Chai H.; Barrett, William E.

    1988-01-01

    Results of research performed for the purpose of studying the sensitivity of multi-layer insulation blanket performance caused by penetrations through the blanket are presented. The work described in this paper presents the experimental data obtained from thermal vacuum tests of various penetration geometries similar to those present on the Hubble Space Telescope. The data obtained from these tests is presented in terms of electrical power required sensitivity factors referenced to a multi-layer blanket without a penetration. The results of these experiments indicate that a significant increase in electrical power is required to overcome the radiation heat losses in the vicinity of the penetrations.

  3. Effect of Liquid Penetrant Sensitivity on Probability of Detection

    NASA Technical Reports Server (NTRS)

    Parker, Bradford H.

    2011-01-01

    The objective of the task is to investigate the effect of liquid penetrant sensitivity level on probability of detection (POD) of cracks in various metals. NASA-STD-5009 currently requires the use of only sensitivity level 4 liquid penetrants for NASA Standard Level inspections. This requirement is based on the fact that the data used to establish the reliably detectable flaw sizes penetrant inspection was from studies performed in the 1970s using penetrant deemed to be equivalent only to modern day sensitivity level 4 penetrants. However, many NDE contractors supporting NASA Centers routinely use sensitivity level 3 penetrants. Because of the new NASA-STD-5009 requirement, these contractors will have to either shift to sensitivity level 4 penetrants or perform formal POD demonstration tests to qualify their existing process. We propose a study to compare the POD generated for two penetrant manufactures, Sherwin and Magnaflux, and for the two most common penetrant inspection methods, water washable and post emulsifiable, hydrophilic. NDE vendors local to GSFC will be employed. A total of six inspectors will inspect a set of crack panels with a broad range of fatigue crack sizes. Each inspector will perform eight inspections of the panel set using the combination of methods and sensitivity levels described above. At least one inspector will also perform multiple inspections using a fixed technique to investigate repeatability. The hit/miss data sets will be evaluated using both the NASA generated DOEPOD software and the MIL-STD-1823 software.

  4. Penetration depth scaling for impact into wet granular packings.

    PubMed

    Brzinski, T A; Schug, J; Mao, K; Durian, D J

    2015-02-01

    We present experimental measurements of penetration depths for the impact of spheres into wetted granular media. We observe that the penetration depth in the liquid saturated case scales with projectile density, size, and drop height in a fashion consistent with the scaling observed in the dry case, but with smaller penetrations. Neither viscous drag nor density effects can explain the enhancement to the stopping force. The penetration depth exhibits a complicated dependence on liquid fraction, accompanied by a change in the drop-height dependence, that must be the consequence of accompanying changes in the conformation of the liquid phase in the interstices. PMID:25768493

  5. Implementing the chemical weapons convention

    SciTech Connect

    Kellman, B.; Tanzman, E. A.

    1999-12-07

    In 1993, as the CWC ratification process was beginning, concerns arose that the complexity of integrating the CWC with national law could cause each nation to implement the Convention without regard to what other nations were doing, thereby causing inconsistencies among States as to how the CWC would be carried out. As a result, the author's colleagues and the author prepared the Manual for National Implementation of the Chemical Weapons Convention and presented it to each national delegation at the December 1993 meeting of the Preparatory Commission in The Hague. During its preparation, the Committee of CWC Legal Experts, a group of distinguished international jurists, law professors, legally-trained diplomats, government officials, and Parliamentarians from every region of the world, including Central Europe, reviewed the Manual. In February 1998, they finished the second edition of the Manual in order to update it in light of developments since the CWC entered into force on 29 April 1997. The Manual tries to increase understanding of the Convention by identifying its obligations and suggesting methods of meeting them. Education about CWC obligations and available alternatives to comply with these requirements can facilitate national response that are consistent among States Parties. Thus, the Manual offers options that can strengthen international realization of the Convention's goals if States Parties act compatibly in implementing them. Equally important, it is intended to build confidence that the legal issues raised by the Convention are finite and addressable. They are now nearing competition of an internet version of this document so that interested persons can access it electronically and can view the full text of all of the national implementing legislation it cites. The internet address, or URL, for the internet version of the Manual is http: //www.cwc.ard.gov. This paper draws from the Manual. It comparatively addresses approximately thirty

  6. EDITORIAL: Special section on foliage penetration

    NASA Astrophysics Data System (ADS)

    Fiddy, M. A.; Lang, R.; McGahan, R. V.

    2004-04-01

    Waves in Random Media was founded in 1991 to provide a forum for papers dealing with electromagnetic and acoustic waves as they propagate and scatter through media or objects having some degree of randomness. This is a broad charter since, in practice, all scattering obstacles and structures have roughness or randomness, often on the scale of the wavelength being used to probe them. Including this random component leads to some quite different methods for describing propagation effects, for example, when propagating through the atmosphere or the ground. This special section on foliage penetration (FOPEN) focuses on the problems arising from microwave propagation through foliage and vegetation. Applications of such studies include the estimation for forest biomass and the moisture of the underlying soil, as well as detecting objects hidden therein. In addition to the so-called `direct problem' of trying to describe energy propagating through such media, the complementary inverse problem is of great interest and much harder to solve. The development of theoretical models and associated numerical algorithms for identifying objects concealed by foliage has applications in surveillance, ranging from monitoring drug trafficking to targeting military vehicles. FOPEN can be employed to map the earth's surface in cases when it is under a forest canopy, permitting the identification of objects or targets on that surface, but the process for doing so is not straightforward. There has been an increasing interest in foliage penetration synthetic aperture radar (FOPEN or FOPENSAR) over the last 10 years and this special section provides a broad overview of many of the issues involved. The detection, identification, and geographical location of targets under foliage or otherwise obscured by poor visibility conditions remains a challenge. In particular, a trade-off often needs to be appreciated, namely that diminishing the deleterious effects of multiple scattering from leaves is

  7. Ground Penetrating Radar Technologies in Ukraine

    NASA Astrophysics Data System (ADS)

    Pochanin, Gennadiy P.; Masalov, Sergey A.

    2014-05-01

    Transient electromagnetic fields are of great interest in Ukraine. The following topics are studied by research teams, with high-level achievements all over the world: (i) Ultra-Wide Band/Short-pulse radar techniques (IRE and LLC "Transient Technologies", for more information please visit http://applied.ire.kharkov.ua/radar%20systems_their%20components%20and%20relevant%20technologies_e.html and http://viy.ua); (ii) Ground Penetrating Radar (GPR) with stepped frequency sounding signals (IRE); (iii) Continuous-Wave (CW) radar with phase-shift keying signals (IRE); and (iv) Radio-wave interference investigation (Scientific and Technical Centre of The Subsurface Investigation, http://geophysics.ua). GPR applications are mainly in search works, for example GPR is often used to search for treasures. It is also used to identify leaks and diffusion of petroleum in soil, in storage areas, as well as for fault location of pipelines. Furthermore, GPR is used for the localization of underground utilities and for diagnostics of the technical state of hydro dams. Deeper GPR probing was performed to identify landslides in Crimea. Rescue radar with CW signal was designed in IRE to search for living people trapped under the rubble of collapsed buildings. The fourth version of this radar has been recently created, showing higher stability and noise immunity. Radio-wave interference investigation allows studying the soil down to tens of meters. It is possible to identify areas with increased conductivity (moisture) of the soil. LLC "Transient Technologies" is currently working with Shevchenko Kyiv University on a cooperation program in which the construction of a test site is one of the planned tasks. In the framework of this program, a GPR with a 300 MHz antenna was handed to the geological Faculty of the University. Employees of "Transient Technologies" held introductory lectures with a practical demonstration for students majoring in geophysics. The authors participated to GPR

  8. Residential heating costs: a comparison of geothermal, solar and conventional resources

    SciTech Connect

    Bloomster, C.H.; Garrett-Price, B.A.; Fassbender, L.L.

    1980-08-01

    The costs of residential heating throughout the United States using conventional, solar, and geothermal energy were determined under current and projected conditions. These costs are very sensitive to location - being dependent on the local prices of conventional energy supplies, local solar insolation, cimate, and the proximity and temperature of potential geothermal resources. The sharp price increases in imported fuels during 1979 and the planned decontrol of domestic oil and natural gas prices have set the stage for geothermal and solar market penetration in the 1980's.

  9. Ice-Penetrating Robot for Scientific Exploration

    NASA Technical Reports Server (NTRS)

    Zimmerman, Wayne; Carsey, Frank; French, Lloyd

    2007-01-01

    The cryo-hydro integrated robotic penetrator system (CHIRPS) is a partially developed instrumentation system that includes a probe designed to deeply penetrate the European ice sheet in a search for signs of life. The CHIRPS could also be used on Earth for similar exploration of the polar ice caps especially at Lake Vostok in Antarctica. The CHIRPS probe advances downward by a combination of simple melting of ice (typically for upper, non-compacted layers of an ice sheet) or by a combination of melting of ice and pumping of meltwater (typically, for deeper, compacted layers). The heat and electric power for melting, pumping, and operating all of the onboard instrumentation and electronic circuitry are supplied by radioisotope power sources (RPSs) and thermoelectric converters energized by the RPSs. The instrumentation and electronic circuitry includes miniature guidance and control sensors and an advanced autonomous control system that has fault-management capabilities. The CHIRPS probe is about 1 m long and 15 cm in diameter. The RPSs generate a total thermal power of 1.8 kW. Initially, as this power melts the surrounding ice, a meltwater jacket about 1 mm thick forms around the probe. The center of gravity of the probe is well forward (down), so that the probe is vertically stabilized like a pendulum. Heat is circulated to the nose by means of miniature pumps and heat pipes. The probe melts ice to advance in a step-wise manner: Heat is applied to the nose to open up a melt void, then heat is applied to the side to allow the probe to slip down into the melt void. The melt void behind the probe is allowed to re-freeze. Four quadrant heaters on the nose and another four quadrant heaters on the rear (upper) surface of the probe are individually controllable for steering: Turning on two adjacent nose heaters on the nose and two adjacent heaters on the opposite side at the rear causes melt voids to form on opposing sides, such that the probe descends at an angle from

  10. Conventionalism and integrable Weyl geometry

    NASA Astrophysics Data System (ADS)

    Pucheu, M. L.

    2015-03-01

    Since the appearance of Einstein's general relativity, gravitation has been associated to the space-time curvature. This theory introduced a geometrodynamic language which became a convenient tool to predict matter behaviour. However, the properties of space-time itself cannot be measurable by experiments. Taking Poincaré idea that the geometry of space-time is merely a convention, we show that the general theory of relativity can be completely reformulated in a more general setting, a generalization of Riemannian geometry, namely, the Weyl integrable geometry. The choice of this new mathematical language implies, among other things, that the path of particles and light rays should now correspond to Weylian geodesies. Such modification in the dynamic of bodies brings a new perception of physical phenomena that we will explore.

  11. Radiological Evaluation of Penetration of the Irrigant according to Three Endodontic Irrigation Techniques

    PubMed Central

    Benkiran, Imane; El Ouazzani, Amal

    2016-01-01

    Introduction. This experimental study is to compare radiographs based on the penetration depth of the irrigant following three final irrigation techniques. Material and Method. A sample of sixty teeth with single roots were prepared with stainless steel K files followed by mechanized Ni-Ti files iRace® under irrigation with 2.5% sodium hypochlorite. Radiopaque solution was utilized to measure the penetration depth of the irrigant. Three irrigation techniques were performed during this study: (i) passive irrigation, (ii) manually activated irrigation, and (iii) passive irrigation with an endodontic needle CANAL CLEAN®. Radiographs were performed to measure the length of irrigant penetration in each technique. Results. In comparison, passive irrigation with a conventional syringe showed infiltration of the irrigant by an average of 0.682 ± 0.105, whereas the manually activated irrigation technique indicated an average of 0.876 ± 0.066 infiltration. Irrigation with an endodontic syringe showed an average infiltration of 0.910 ± 0.043. The results revealed highly significant difference between the three irrigation techniques (α = 5%). Conclusion. Adding manual activation to the irrigant improved the result by 20%. This study indicates that passive irrigation with an endodontic needle has proved to be the most effective irrigation technique of the canal system. PMID:27433162

  12. Experiments in Support of Pressure Enhanced Penetration with Shaped Charge Perforators

    SciTech Connect

    Glenn, L.A.; Chase, J.B.; Barker, J.; Leidel, D.J.

    1999-11-01

    Computational analysis demonstrated that the penetration of a shaped charge could be substantially enhanced by imploding the liner in a high pressure light gas atmosphere. The gas pressure helps confine the jet on the axis of penetration in the latter stages of formation. A light gas, such as helium or hydrogen, is required in order to keep the gas density low enough so as not to inhibit liner collapse. These results have now been confirmed by experiment. Identical 5-foot long guns, each containing 37 perforators at a shot density of 12 SPF, were inserted in two API Section 1 concrete targets, poured on the same day and cured for the same period. One of the guns was fired with interior ambient (0.1 MPa) air pressure and the other with helium at 13.8 MPa (2,000 psia). The average penetration from the 37 perforations with the helium system increased 40.3% over that obtained with the conventional system.

  13. Enabling Greater Penetration of Solar Power via the Use of CSP with Thermal Energy Storage

    SciTech Connect

    Denholm, P.; Mehos, M.

    2011-11-01

    At high penetration of solar generation there are a number of challenges to economically integrating this variable and uncertain resource. These include the limited coincidence between the solar resource and normal demand patterns and limited flexibility of conventional generators to accommodate variable generation resources. Of the large number of technologies that can be used to enable greater penetration of variable generators, concentrating solar power (CSP) with thermal energy storage (TES) presents a number of advantages. The use of storage enables this technology to shift energy production to periods of high demand or reduced solar output. In addition, CSP can provide substantial grid flexibility by rapidly changing output in response to the highly variable net load created by high penetration of solar (and wind) generation. In this work we examine the degree to which CSP may be complementary to PV by performing a set of simulations in the U.S. Southwest to demonstrate the general potential of CSP with TES to enable greater use of solar generation, including additional PV.

  14. Ground penetrating radar characterization of a landfill

    NASA Astrophysics Data System (ADS)

    Yochim, April Theresa

    Ground penetrating radar was investigated in an active landfill to determine if the in-situ water content could be measured. Water content is an important parameter in predicting the generation of landfill gas (LFG), an important renewable energy source. Unfortunately, predicting the quantity of LFG is difficult due to the heterogeneities present in a landfill and the lack of in-situ input parameters. GPR is a non-invasive, near-surface geophysical technique that provides high resolution images of dielectric properties in the earth's subsurface. A transmitter emits high frequency (10 - 1000 MHz) electromagnetic pulses through the subsurface, with the receiver recording the echo. Specialized software is then used to create images of the subsurface. The challenge with using GPR in landfills is the heterogeneity of the subsurface and the clay cap linear covering landfills, both affecting the transmission of the electromagnetic pulses. The use of GPR in a landfill was evaluated at the Region of Waterloo's Waste Management Centre. Measurements were completed using both the surface and the borehole approach. The results indicated that a borehole GPR can be used, with successful measurement of water content a function of borehole separation distance and frequency of the electromagnetic pulses. The developed approach was confirmed at the City of Hamilton's Glanbrook Landfill. The successful comparison of in-situ water content values to laboratory determined values at both landfills shows that GPR can be used to measure in-situ water content.

  15. Universal framework for unmanned system penetration testing

    NASA Astrophysics Data System (ADS)

    Kobezak, Philip; Abbot-McCune, Sam; Tront, Joseph; Marchany, Randy; Wicks, Alfred

    2013-05-01

    Multiple industries, from defense to medical, are increasing their use of unmanned systems. Today, many of these systems are rapidly designed, tested, and deployed without adequate security testing. To aid the quick turnaround, commercially available subsystems and embedded components are often used. These components may introduce security vulnerabilities particularly if the designers do not fully understand their functionality and limitations. There is a need for thorough testing of unmanned systems for security vulnerabilities, which includes all subsystems. Using a penetration testing framework would help find these vulnerabilities across different unmanned systems applications. The framework should encompass all of the commonly implemented subsystems including, but not limited to, wireless networks, CAN buses, passive and active sensors, positioning receivers, and data storage devices. Potential attacks and vulnerabilities can be identified by looking at the unique characteristics of these subsystems. The framework will clearly outline the attack vectors as they relate to each subsystem. If any vulnerabilities exist, a mitigation plan can be developed prior to the completion of the design phase. Additionally, if the vulnerabilities are known in advance of deployment, monitoring can be added to the design to alert operators of any attempted or successful attacks. This proposed framework will help evaluate security risks quickly and consistently to ensure new unmanned systems are ready for deployment. Verifying that a new unmanned system has passed a comprehensive security evaluation will ensure greater confidence in its operational effectiveness.

  16. Pavement thickness evaluation using ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Harris, Dwayne Arthur

    Accurate knowledge of pavement thickness is important information to have both at a network and project level. This information aids in pavement management and design. Much of the time this information is missing, out of date, or unknown for highway sections. Current technologies for determining pavement thickness are core drilling, falling weight deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavement thickness information; however, it is also time consuming, labor intensive, intrusive to traffic, destructive, and limited in coverage. FWD provides nondestructive estimates of both a surface thickness and total pavement structure thickness, including pavement, base and sub-base. On the other hand, FWD is intrusive to traffic and affected by the limitations and assumptions the method used to estimate thickness. GPR provides pavement surface course thickness estimates with excellent data coverage at highway speed. Yet, disadvantages include the pavement thickness estimation being affected by the electrical properties of the pavement, limitations of the system utilized, and heavy post processing of the data. Nevertheless, GPR has been successfully utilized by a number of departments of transportation (DOTs) for pavement thickness evaluation. This research presents the GPR thickness evaluation methods, develops GPRPAVZ the software used to implement the methodologies, and addresses the quality of GPR pavement thickness evaluation.

  17. Ground-penetrating radar: use and misuse

    NASA Astrophysics Data System (ADS)

    Olhoeft, Gary R.

    1999-10-01

    Ground penetrating radar (GPR) has been used to explore the subsurface of the earth since 1929. Over the past 70 years, it has been widely used, misused and abused. Use includes agriculture, archaeology, environmental and geotechnical site characterization, minerals, groundwater and permafrost exploration, tunnel, utility, and unexploded ordnance location, dam inspection, and much more. Misuse includes mistaking above ground reflections for subsurface events or mapping things from off to the side as if they were directly below, synthetic aperture processing of dispersive data, minimum phase deconvolution, locating objects smaller than resolution limits of the wavelength in the ground, ignoring Fresnel zone limitations in mapping subsurface structure, processing radar data through seismic software packages without allowing for the differences, mapping the bottom of metal pipes from the top, claiming to see through thousands of feet of sediments, and more. GPR is also being abused as the regulatory environment changes and the radiofrequency spectrum is becoming more crowded by cellular phones, pagers, garage door openers, wireless computer networks, and the like. It is often thought to be a source of interference (though it never is) and it is increasingly interfered with by other radiofrequency transmitters.

  18. Adsorption of polymer chains at penetrable interfaces

    SciTech Connect

    Gerasimchuk, I. V.; Sommer, J.-U.; Gerasimchuk, V. S.

    2011-03-15

    We investigate the problem of adsorption (localization) of polymer chains in the system of two penetrable interfaces within the mean-field approximation. The saturation of the polymer system in the limit case of zero bulk concentration is studied. We find the exact solution of this mean-field polymer adsorption problem that opens the possibility to treat various localization problems for polymer chains in such environments using appropriate boundary conditions. The exact solution is controlled by a single scaling variable that describes the coupling between the interfaces due to the polymer chains. We obtain a nonmonotonic behavior of the amount of adsorbed polymers as a function of the distance between the interfaces. This leads to a high-energy and a low-energy phase for the double layer with respect to the amount of polymers localized. At the saturation point, we find the total energy of the system and determine the force acting between the interfaces to be strictly attractive and to monotonically decay to zero when the interface distance increases.

  19. Low Force Icy Regolith Penetration Technology

    NASA Technical Reports Server (NTRS)

    Metzger, P. T.; Galloway, G. M.; Mantovani, J. G.; Zacny, K.; Zacny, Kris; Craft, Jack

    2011-01-01

    Recent data from the Moon, including LCROSS data, indicate large quantities of water ice and other volatiles frozen into the soil in the permanently shadowed craters near the poles. If verified and exploited, these volatiles will revolutionize spaceflight as an inexpensive source of propellants and other consumables outside Earth's gravity well. This report discusses a preliminary investigation of a method to insert a sensor through such a soiVice mixture to verify the presence, nature, and concentration of the ice. It uses percussion to deliver mechanical energy into the frozen mixture, breaking up the ice and decompacting the soil so that only low reaction forces are required from a rover or spacecraft to push the sensor downward. The tests demonstrate that this method may be ideal for a small platform in lunar gravity. However, there are some cases where the system may not be able to penetrate the icy soil, and there is some risk ofthe sensor becoming stuck so that it cannot be retracted, so further work is needed. A companion project (ISDS for Water Detection on the Lunar Surface) has performed preliminary investigation of a dielectric/thermal sensor for use with this system.

  20. Membranotropic Cell Penetrating Peptides: The Outstanding Journey

    PubMed Central

    Falanga, Annarita; Galdiero, Massimiliano; Galdiero, Stefania

    2015-01-01

    The membrane bilayer delimits the interior of individual cells and provides them with the ability to survive and function properly. However, the crossing of cellular membranes constitutes the principal impediment to gaining entry into cells, and the potential therapeutic application of many drugs is predominantly dependent on the development of delivery tools that should take the drug to target cells selectively and efficiently with only minimal toxicity. Cell-penetrating peptides are short and basic peptides are widely used due to their ability to deliver a cargo across the membrane both in vitro and in vivo. It is widely accepted that their uptake mechanism involves mainly the endocytic pathway, the drug is catched inside endosomes and lysosomes, and only a small quantity is able to reach the intracellular target. In this wide-ranging scenario, a fascinating novel hypothesis is that membranotropic peptides that efficiently cross biological membranes, promote lipid-membrane reorganizing processes and cause a local and temporary destabilization and reorganization of the membrane bilayer, may also be able to enter cells circumventing the endosomal entrapment; in particular, by either favoring the escape from the endosome or by direct translocation. This review summarizes current data on membranotropic peptides for drug delivery. PMID:26512649

  1. Field Dependent Penetration Depth in YBCO

    NASA Astrophysics Data System (ADS)

    Carrington, A.; Giannetta, R.; Salamon, M. B.; Ginsberg, D. M.; Kim, J. T.

    1997-03-01

    An important step to understanding the nature of superconductivity in cuprate superconductors was the observation of a linear temperature dependence of the penetration depth (λ_ab) in YBCO(W.N. Hardy et al.) Phys. Rev. Lett. 70, 3999 (1993)., which strongly suggests the presence of line nodes in the order parameter, consistent with a d-wave pairing state. Recent theoretical work(S.K. Yip and J.A. Sauls, Phys. Rev. Lett. 69), 2264 (1992). has claimed that the magnetic field dependence of λ_ab at low temperature also uniquely depends on the symmetry of the order parameter. To investigate these effects we have built an apparatus, based on a RF tunnel diode oscillator,to measure with high precision both the temperature and field dependence of λ in small single crystal samples. Particular attention has been paid to reducing extraneous frequency shifts originating from the field/temperature dependence of the oscillator circuit. The sample rests on a moveable stage whose temperature may be varied indepndently of the resonator, so that the background may be measured in-situ. Results will be presented for YBCO at temperatures down to 1.3 K and fields up to H_c1(T), and their implications for the the pairing state in the cuprates discussed. This work was supported by NSF Grant # DMR-89-20538 and STCS/NSF DMR 91-20000.

  2. 40 CFR 1065.376 - Chiller NO2 penetration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Chiller NO2 penetration. 1065.376... Chiller NO2 penetration. (a) Scope and frequency. If you use a chiller to dry a sample upstream of a NOX measurement instrument, but you don't use an NO2-to-NO converter upstream of the chiller, you must...

  3. Mars penetrator umbilical. [to study geophysical properties of Mars

    NASA Technical Reports Server (NTRS)

    Barns, C. E.

    1979-01-01

    The device proposed to gather subsurface data on the planet Mars is a ballistic probe which penetrates the soil after a free fall through the Martian atmosphere. Highlights of the design, development, and testing of several features of the Mars Surface Penetration Probe are outlined.

  4. 46 CFR 174.225 - Hull penetrations and shell connections.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Hull penetrations and shell connections. 174.225 Section 174.225 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... § 174.225 Hull penetrations and shell connections. Each overboard discharge and shell connection...

  5. 46 CFR 174.225 - Hull penetrations and shell connections.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Hull penetrations and shell connections. 174.225 Section 174.225 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... § 174.225 Hull penetrations and shell connections. Each overboard discharge and shell connection...

  6. 46 CFR 174.225 - Hull penetrations and shell connections.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Hull penetrations and shell connections. 174.225 Section 174.225 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... § 174.225 Hull penetrations and shell connections. Each overboard discharge and shell connection...

  7. 46 CFR 174.225 - Hull penetrations and shell connections.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Hull penetrations and shell connections. 174.225 Section 174.225 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... § 174.225 Hull penetrations and shell connections. Each overboard discharge and shell connection...

  8. 46 CFR 174.225 - Hull penetrations and shell connections.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Hull penetrations and shell connections. 174.225 Section 174.225 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... § 174.225 Hull penetrations and shell connections. Each overboard discharge and shell connection...

  9. 40 CFR 1065.376 - Chiller NO2 penetration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Chiller NO2 penetration. 1065.376... Chiller NO2 penetration. (a) Scope and frequency. If you use a chiller to dry a sample upstream of a NOX measurement instrument, but you don't use an NO2-to-NO converter upstream of the chiller, you must...

  10. 40 CFR 1065.376 - Chiller NO2 penetration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Chiller NO2 penetration. 1065.376... Chiller NO2 penetration. (a) Scope and frequency. If you use a chiller to dry a sample upstream of a NOX measurement instrument, but you don't use an NO2-to-NO converter upstream of the chiller, you must...

  11. 40 CFR 1065.376 - Chiller NO2 penetration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Chiller NO2 penetration. 1065.376... Chiller NO2 penetration. (a) Scope and frequency. If you use a chiller to dry a sample upstream of a NOX measurement instrument, but you don't use an NO2-to-NO converter upstream of the chiller, you must...

  12. Rock penetration : finite element sensitivity and probabilistic modeling analyses.

    SciTech Connect

    Fossum, Arlo Frederick

    2004-08-01

    This report summarizes numerical analyses conducted to assess the relative importance on penetration depth calculations of rock constitutive model physics features representing the presence of microscale flaws such as porosity and networks of microcracks and rock mass structural features. Three-dimensional, nonlinear, transient dynamic finite element penetration simulations are made with a realistic geomaterial constitutive model to determine which features have the most influence on penetration depth calculations. A baseline penetration calculation is made with a representative set of material parameters evaluated from measurements made from laboratory experiments conducted on a familiar sedimentary rock. Then, a sequence of perturbations of various material parameters allows an assessment to be made of the main penetration effects. A cumulative probability distribution function is calculated with the use of an advanced reliability method that makes use of this sensitivity database, probability density functions, and coefficients of variation of the key controlling parameters for penetration depth predictions. Thus the variability of the calculated penetration depth is known as a function of the variability of the input parameters. This simulation modeling capability should impact significantly the tools that are needed to design enhanced penetrator systems, support weapons effects studies, and directly address proposed HDBT defeat scenarios.

  13. An explosive acoustic telemetry system for seabed penetrators

    SciTech Connect

    Hauser, G.C.; Hickerson, J.

    1988-04-01

    This report discusses the design and past applications of an explosive acoustic telemetry system (EATS) for gathering and transmitting data from seabed penetrators. The system was first fielded in 1982 and has since been used to measure penetrator performance on three other occasions. Descriptions are given of the mechanical hardware, system electronics, and software.

  14. Shape optimization of high-speed penetrators: a review

    NASA Astrophysics Data System (ADS)

    Ben-Dor, Gabi; Dubinsky, Anatoly; Elperin, Tov

    2012-12-01

    In spite of a large number of publications on shape optimization of penetrating projectiles there are no dedicated surveys of these studies. The goal of the present review is to close this gap. The review includes more than 50 studies published since 1980 and devoted to solving particular problems of shape optimization of high-speed penetrators. We analyze publications which employed analytical and numerical method for shape optimization of high-speed penetrators against concrete, metal, fiber-reinforced plastic laminate and soil shields. We present classification of the mathematical models used for describing interaction between a penetrator and a shield. The reviewed studies are summarized in the table where we display the following information: the model; indicate whether the model accounts for or neglects friction at the surface of penetrator; criterion for optimization (depth of penetration into a semi-infinite shield, ballistic limit velocity for a shield having a finite thickness, several criteria); class of considered shapes of penetrators (bodies of revolution, different classes of 3-D bodies, etc.); method of solution (analytical or numerical); in comments we present additional information on formulation of the optimization problem. The survey also includes discussion on certain methodological facets in formulating shape optimization problems for high-speed penetrators.

  15. Penetration mechanics research in the former Soviet Union

    NASA Astrophysics Data System (ADS)

    Isbell, W. M.; Anderson, C. E.; Asay, J. R.; Bless, S. J.; Grady, D. E.

    1992-09-01

    Recently published papers by scientists from the former Soviet Union reveal to Western researchers a mature body of highly inventive and dedicated research. To analyze and assess this work, a group of six internationally recognized U.S. experts in the field of penetration mechanics and hypervelocity impact reviewed hundreds of unclassified documents. Five broad, sometimes overlapping, research areas were chosen for assessment: hypervelocity impact capabilities; penetration mechanics experiments at ordnance velocities; analytical penetration mechanics; material response to high-velocity impact and penetration; and numerical simulations of penetration physics. Both similarities and differences between Soviet and Western research were noted and characterized, with particular attention paid to potential breakthrough technologies. Leading Soviet scientists and their organizations were identified, as were areas of potentially fruitful collaboration between researchers from the former Soviet Union and the United States. Soviet breakthroughs in penetration mechanics technology that far out-distanced Western efforts were not found, though potential breakthroughs were noted in several areas, including penetration models of brittle materials (principally ceramics), superdeep penetration of particles, and very-high-velocity electromagnetic launchers.

  16. Multidisciplinary Team Treatment of Penetrating Head and Neck Trauma.

    PubMed

    Li, Lili; Li, Hongxing; Yang, Kongbin

    2016-09-01

    Penetrating head and neck trauma could cause significant mortality because of many important structures located in the brain and neck. Although high-velocity penetrating brain injury is often reported, reports of low-velocity, combined head and neck penetrating injury are rare. Hereby, the authors present a case of an old man who had encountered a serious accident, a 29-cm iron fork penetrated into his neck, through the skull base and into brain. After treatment by multidisciplinary team, the patient was in rehabilitation. The multidisciplinary team assists rapid diagnosis and treatment of penetrating neck and head injury is the key to ensure a good outcome. Therefore, as the authors face such patients again, a multidisciplinary team is needed. PMID:27428914

  17. Penetration of varnishes into demineralized root dentine in vitro.

    PubMed

    Arends, J; Duschner, H; Ruben, J L

    1997-01-01

    In this paper the penetration of three different varnishes employed in caries prevention (Duraphat, Fluor Protector and Cervitec) into demineralized dentine is quantified using confocal laser scanning microscopy. The results show that the varnish penetration into lesions about 85 microns in depth if for Cervitec about 35 microns and considerably less for Duraphat and Fluor Protector. The penetration is into the dentinal tubules and is influenced by dentinal tubule direction. The drying procedure--pretreatment of the dentine--influences the penetration, though sizeably only for Cervitec applications. This paper shows that varnish penetration into the tissue and presumably 'sealing' tubules completely or partly is valuable with respect to root caries prevention and hypersensitivity. PMID:9165191

  18. Evaporation and skin penetration characteristics of mosquito repellent formulations

    SciTech Connect

    Reifenrath, W.G.; Hawkins, G.S.; Kurtz, M.S.

    1989-03-01

    Formulations of the mosquito repellent N,N-diethyl-3-methylbenzamide (deet) in combination with a variety of additives were developed to control repellent evaporation and percutaneous penetration. Deet was also formulated with the repellent dimethyl phthalate to study the interaction of the two compounds on the skin. The evaporation and penetration processes were evaluated on whole and split-thickness pig skin using radiolabeled repellents with an in vitro apparatus. Under essentially still air and air flow conditions, one of the deet formulations resulted in significantly reduced total evaporation and percutaneous penetration of deet as compared to unformulated repellent. When deet and dimethyl phthalate were combined, neither repellent affected the total amount of evaporation and penetration of the other compound. However, initial percutaneous penetration and evaporation rates were slightly less and decayed less rapidly than when both chemicals were tested separately at the same dose. These results indicated a degree of competition of the two compounds for the same avenues of loss.

  19. Penetrator mission concepts for exploration of the Galilean satellites

    NASA Technical Reports Server (NTRS)

    Friedlander, A. L.; Niehoff, J. C.; Davis, D. R.

    1976-01-01

    Penetrators are elongated missile-shaped objects designed to implant scientific instrumentation to depths of 1 to 15 meters in a wide variety of soil. A typical penetrator weighs 35 kg and impacts the surface at 150 m/sec oriented as close as possible to vertical. A spacecraft bus carries the penetrators to the target body, controls their deployment, and serves as a data communications relay. The analysis addresses the question of basic feasibility and covers such topics as trajectory requirements and delivered mass capability, deployment modes and penetrator retro sizing, impact site accessibility, guidance and control, and penetrator/bus communications. We conclude that such missions, while difficult in many respects, appear to be technically feasible in the context of Jovian system exploration in the post-1985 time period.

  20. Droplet Impact and Penetration on a Series of Capillary Tubes

    NASA Astrophysics Data System (ADS)

    Hosseini, Saman; Dalili, Alireza; Ashgriz, Nasser; Chandra, Sanjeev

    2013-11-01

    A series of experiments were carried out in which a single droplet of water was deposited onto a substrate having a series of closely spaced parallel-holes to represent a simple porous media. At the center of the width of the 0.6'' × 0.5'' × 0.3'' poly-carbonate substrate seven through-holes each with a diameter of 300 μm and distance of 300 μm from one another were drilled in a straight line. Droplets with diameters of 3.2 and 2.0 mm were released from heights of 1, 3 and 5 cm. Using a high-speed camera the impact, spreading and capillary penetration of the droplets into the holes were videotaped. Two different penetration regimes were observed based on the impact velocity. At low droplet impact velocities, the penetration was mainly due to capillary forces, while at higher impact velocities the penetration occurred at two stages. The first stage was inertia driven, while the second stage was capillary driven penetration. The threshold velocity for liquid penetration into the holes was formulated. Inertia forces were used to describe the linear portion of penetration and the Lucas-Washburn equation was used to characterize the non-linear (capillary) part of penetration. The distance of penetration as a function of time was worked out using this equation. Droplet oscillation on the top of the parallel holes was observed as well. It was evident that the area of the penetration inside the holes played a major role in the kinetic energy dissipation and the damping of the oscillation.

  1. High-performance TSD bits improve penetration rate. [Thermally Stable Diamond

    SciTech Connect

    Cohen, J.H.; Maurer, W.C. ); Westcott, P.A. )

    1993-04-12

    Optimizing the number, size, and orientation of clutters on thermally stable diamond (TSD) bits increases penetration rate and extends bit life. The use of optimized TSD (also commonly referred to as thermally stable product or TSP) bits on high-power drilling motors can greatly reduce drilling time for harsh-environment wells, such as deep gas wells. The power delivered to the rock governs drilling rate, and at high speed the optimized TSD bits are capable of effectively delivering power to drill the rock. This article reviews a 3-year project to develop advanced thermally stable diamond bits that can operate at a power level 5-10 times greater than that typically delivered by conventional rotary drilling. These bits are designed to operate on advanced drilling motors that drill three to six times faster than rotary drilling. These advanced bits and motors are especially designed for use in slim-hole and horizontal drilling applications. The TSD bit design parameters which were varied during the tests were cutter size, shape, density (number of cutters), and orientation. Drilling tests in limestone, sandstone, marble, and granite blocks showed that these optimized bits drilled many of these rocks at 500-1,000 ft/hr compared to 50-100 ft/hr for conventional rotary drilling. A sensitivity model showed that doubling the rate of penetration significantly reduced the time to drill a well and reduced costs by 13 %.

  2. Conventional treatments for ankylosing spondylitis

    PubMed Central

    Dougados, M; Dijkmans, B; Khan, M; Maksymowych, W; van der Linden, S.; Brandt, J

    2002-01-01

    Management of ankylosing spondylitis (AS) is challenged by the progressive nature of the disease. To date, no intervention is available that alters the underlying mechanism of inflammation in AS. Currently available conventional treatments are palliative at best, and often fail to control symptoms in the long term. Current drug treatment may perhaps induce a spurious state of "disease remission," which is merely a low level of disease activity. Non-steroidal anti-inflammatory drugs are first line treatment, but over time, the disease often becomes refractory to these agents. Disease modifying antirheumatic drugs are second line treatment and may offer some clinical benefit. However, conclusive evidence of the efficacy of these drugs from large placebo controlled trials is lacking. Additionally, these drugs can cause treatment-limiting adverse effects. Intra-articular corticosteroid injection guided by arthrography, computed tomography, or magnetic resonance imaging is an effective means of reducing inflammatory back pain, but controlled studies are lacking. A controlled study has confirmed moderate but significant efficacy of intravenous bisphosphonate (pamidronate) treatment in patients with AS; further evaluation of bisphosphonate treatment is warranted. Physical therapy and exercise are necessary adjuncts to pharmacotherapy; however, the paucity of controlled data makes it difficult to identify the best way to administer these interventions. Surgical intervention may be required to support severe structural damage. Thus, for patients with AS, the future of successful treatment lies in the development of pharmacological agents capable of both altering the disease course through intervention at sites of disease pathogenesis, and controlling symptoms. PMID:12381510

  3. Severe accident testing of electrical penetration assemblies

    SciTech Connect

    Clauss, D.B. )

    1989-11-01

    This report describes the results of tests conducted on three different designs of full-size electrical penetration assemblies (EPAs) that are used in the containment buildings of nuclear power plants. The objective of the tests was to evaluate the behavior of the EPAs under simulated severe accident conditions using steam at elevated temperature and pressure. Leakage, temperature, and cable insulation resistance were monitored throughout the tests. Nuclear-qualified EPAs were produced from D. G. O'Brien, Westinghouse, and Conax. Severe-accident-sequence analysis was used to generate the severe accident conditions (SAC) for a large dry pressurized-water reactor (PWR), a boiling-water reactor (BWR) Mark I drywell, and a BWR Mark III wetwell. Based on a survey conducted by Sandia, each EPA was matched with the severe accident conditions for a specific reactor type. This included the type of containment that a particular EPA design was used in most frequently. Thus, the D. G. O'Brien EPA was chosen for the PWR SAC test, the Westinghouse was chosen for the Mark III test, and the Conax was chosen for the Mark I test. The EPAs were radiation and thermal aged to simulate the effects of a 40-year service life and loss-of-coolant accident (LOCA) before the SAC tests were conducted. The design, test preparations, conduct of the severe accident test, experimental results, posttest observations, and conclusions about the integrity and electrical performance of each EPA tested in this program are described in this report. In general, the leak integrity of the EPAs tested in this program was not compromised by severe accident loads. However, there was significant degradation in the insulation resistance of the cables, which could affect the electrical performance of equipment and devices inside containment at some point during the progression of a severe accident. 10 refs., 165 figs., 16 tabs.

  4. Market penetration of biodiesel and ethanol

    NASA Astrophysics Data System (ADS)

    Szulczyk, Kenneth Ray

    This dissertation examines the influence that economic and technological factors have on the penetration of biodiesel and ethanol into the transportation fuels market. This dissertation focuses on four aspects. The first involves the influence of fossil fuel prices, because biofuels are substitutes and have to compete in price. The second involves biofuel manufacturing technology, principally the feedstock-to-biofuel conversion rates, and the biofuel manufacturing costs. The third involves prices for greenhouse gas offsets. The fourth involves the agricultural commodity markets for feedstocks, and biofuel byproducts. This dissertation uses the Forest and Agricultural Sector Optimization Model-Greenhouse Gas (FASOM-GHG) to quantitatively examine these issues and calculates equilibrium prices and quantities, given market interactions, fossil fuel prices, carbon dioxide equivalent prices, government biofuel subsidies, technological improvement, and crop yield gains. The results indicate that for the ranges studied, gasoline prices have a major impact on aggregate ethanol production but only at low prices. At higher prices, one runs into a capacity constraint that limits expansion on the capacity of ethanol production. Aggregate biodiesel production is highly responsive to gasoline prices and increases over time. (Diesel fuel price is proportional to the gasoline price). Carbon dioxide equivalent prices expand the biodiesel industry, but have no impact on ethanol aggregate production when gasoline prices are high again because of refinery capacity expansion. Improvement of crop yields shows a similar pattern, expanding ethanol production when the gasoline price is low and expanding biodiesel. Technological improvement, where biorefinery production costs decrease over time, had minimal impact on aggregate ethanol and biodiesel production. Finally, U.S. government subsidies have a large expansionary impact on aggregate biodiesel production. Finally, U.S. government

  5. Ground penetrating radar field evaluation in Angola

    NASA Astrophysics Data System (ADS)

    Walls, Richard; Brown, Todd; Clodfelter, Fred; Coors, Jeff; Laudato, Stephen; Lauziere, Steve; Patrikar, Ajay; Poole, Michael; Price, Mike

    2006-05-01

    Deminers around the globe are still using handheld metal detectors that lack the capability to distinguish mines from clutter, detect mines containing very little metal, or find mines buried at deeper depths. In the southern African country of Angola, many areas and roads are impassable due to the threat of anti-tank landmines. Some of these mines are undetectable using current metal detector technology. The US Army has funded the development of the NIITEK ground penetrating radar (GPR) for detection of anti-tank (AT) landmines. This radar detects metal and plastic mines as well as mines that are buried too deep for handheld metal detectors to find. The US Department of Defense Humanitarian Demining (HD) Research & Development Program focuses on developing, testing, demonstrating, and validating new technology for immediate use in humanitarian demining operations around the globe. The HD team provided funding and guidance to NIITEK Incorporated for development of a prototype system called Mine Stalker - a relatively light-weight, remote-controlled vehicle outfitted with the NIITEK GPR, detection algorithms, and a marking system. Individuals from the HD team, NIITEK Inc, and the non-governmental organization Meschen Gegen Minen (MgM) participated in a field evaluation of the Mine Stalker in Angola. The primary aim was to evaluate the effectiveness and reliability of the NIITEK GPR under field conditions. The Mine Stalker was extremely reliable during the evaluation with no significant maintenance issues. All AT mines used to verify GPR performance were detected, even when buried to depths as deep as 25-33cm.

  6. Prediction of Drug Penetration in Tuberculosis Lesions.

    PubMed

    Sarathy, Jansy P; Zuccotto, Fabio; Hsinpin, Ho; Sandberg, Lars; Via, Laura E; Marriner, Gwendolyn A; Masquelin, Thierry; Wyatt, Paul; Ray, Peter; Dartois, Véronique

    2016-08-12

    The penetration of antibiotics in necrotic tuberculosis lesions is heterogeneous and drug-specific, but the factors underlying such differential partitioning are unknown. We hypothesized that drug binding to macromolecules in necrotic foci (or caseum) prevents passive drug diffusion through avascular caseum, a critical site of infection. Using a caseum binding assay and MALDI mass spectrometry imaging of tuberculosis drugs, we showed that binding to caseum inversely correlates with passive diffusion into the necrotic core. We developed a high-throughput assay relying on rapid equilibrium dialysis and a caseum surrogate designed to mimic the composition of native caseum. A set of 279 compounds was profiled in this assay to generate a large data set and explore the physicochemical drivers of free diffusion into caseum. Principle component analysis and modeling of the data set delivered an in silico signature predictive of caseum binding, combining 69 molecular descriptors. Among the major positive drivers of binding were high lipophilicity and poor solubility. Determinants of molecular shape such as the number of rings, particularly aromatic rings, number of sp(2) carbon counts, and volume-to-surface ratio negatively correlated with the free fraction, indicating that low-molecular-weight nonflat compounds are more likely to exhibit low caseum binding properties and diffuse effectively through caseum. To provide simple guidance in the property-based design of new compounds, a rule of thumb was derived whereby the sum of the hydrophobicity (clogP) and aromatic ring count is proportional to caseum binding. These tools can be used to ensure desirable lesion partitioning and guide the selection of optimal regimens against tuberculosis. PMID:27626295

  7. Groundwater contamination downstream of a contaminant penetration site. II. Horizontal penetration of the contaminant plume

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    2002-01-01

    Part I of this study (Rubin, H.; Buddemeier, R.W. Groundwater Contamination Downstream of a Contaminant Penetration Site Part 1: Extension-Expansion of the Contaminant Plume. J. of Environmental Science and Health Part A (in press).) addressed cases, in which a comparatively thin contaminated region represented by boundary layers (BLs) developed within the freshwater aquifer close to contaminant penetration site. However, at some distance downstream from the penetration site, the top of the contaminant plume reaches the top or bottom of the aquifer. This is the location of the "attachment point," which comprises the entrance cross section of the domain evaluated by the present part of the study. It is shown that downstream from the entrance cross section, a set of two BLs develop in the aquifer, termed inner and outer BLs. It is assumed that the evaluated domain, in which the contaminant distribution gradually becomes uniform, can be divided into two sections, designated: (a) the restructuring section, and (b) the establishment section. In the restructuring section, the vertical concentration gradient leads to expansion of the inner BL at the expense of the outer BL, and there is almost no transfer of contaminant mass between the two layers. In the establishment section, each of the BLs occupies half of the aquifer thickness, and the vertical concentration gradient leads to transfer of contaminant mass from the inner to the outer BL. By use of BL approximations, changes of salinity distribution in the aquifer are calculated and evaluated. The establishment section ends at the uniformity point, downstream from which the contaminant concentration profile is practically uniform. The length of the restructuring section, as well as that of the establishment section, is approximately proportional to the aquifer thickness squared, and is inversely proportional to the transverse dispersivity. The study provides a convenient set of definitions and terminology that are

  8. The Incidence of Acetabular Osteolysis in Young Patients With Conventional versus Highly Crosslinked Polyethylene

    PubMed Central

    Mall, Nathan A.; Nunley, Ryan M.; Zhu, Jin Jun; Maloney, William J.; Barrack, Robert L.

    2010-01-01

    Background Osteolysis is a major mode of hip implant failure. Previous literature has focused on the amount of polyethylene wear comparing highly crosslinked polyethylene (HXPLE) with conventional liners but has not clarified the relative incidence of osteolysis with these two liners. Questions/purposes We determined (1) the incidence of osteolysis in HXLPE versus conventional polyethylene (CPE), (2) the ability to detect and evaluate the size of lytic lesions using radiographs compared with CT scans, (3) head penetration in hips without and with lysis, and (4) determined whether acetabular position, head size, and UCLA activity score contributed to lysis. Methods We compared head penetration and osteolysis on plain radiographs and presence and volume of osteolysis on CT scans in 48 patients with HXLPE (mean, 46.5 years) and 50 patients with CPE (mean, 43.2 years). The minimum followup was 5 years (average, 7.2 years; range, 5.1–10.9 years), Results Osteolysis was apparent on CT in a larger number of patients with CPE liners than HXLPE liners: 12 of 50 (24%) versus one of 48 (2%), respectively. We found no correlation between head penetration and volume of osteolytic lesions. Head penetration was greater in patients with osteolysis. Smaller head sizes were associated with greater wear and those with osteolysis had smaller head sizes; however, there was no difference in acetabular component position or UCLA activity in those with lysis compared with those without. Conclusions HXLPE diminished the incidence of osteolysis, but the lack of correlation between penetration and volume of osteolysis suggests other factors other than wear contribute to the development of osteolysis. Level of Evidence Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. PMID:20824407

  9. 40 CFR 401.16 - Conventional pollutants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Conventional pollutants. 401.16 Section... STANDARDS GENERAL PROVISIONS § 401.16 Conventional pollutants. The following comprise the list of conventional pollutants designated pursuant to section 304(a)(4) of the Act: 1. Biochemical oxygen demand...

  10. 32 CFR 643.128 - Veterans' conventions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 4 2014-07-01 2013-07-01 true Veterans' conventions. 643.128 Section 643.128... ESTATE Additional Authority of Commanders § 643.128 Veterans' conventions. Without reference to higher... veterans' organizations for use at State or national conventions or for national youth, athletic,...

  11. 32 CFR 643.128 - Veterans' conventions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 4 2013-07-01 2013-07-01 false Veterans' conventions. 643.128 Section 643.128... ESTATE Additional Authority of Commanders § 643.128 Veterans' conventions. Without reference to higher... veterans' organizations for use at State or national conventions or for national youth, athletic,...

  12. 32 CFR 643.128 - Veterans' conventions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Veterans' conventions. 643.128 Section 643.128... ESTATE Additional Authority of Commanders § 643.128 Veterans' conventions. Without reference to higher... veterans' organizations for use at State or national conventions or for national youth, athletic,...

  13. 32 CFR 643.128 - Veterans' conventions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 4 2012-07-01 2011-07-01 true Veterans' conventions. 643.128 Section 643.128... ESTATE Additional Authority of Commanders § 643.128 Veterans' conventions. Without reference to higher... veterans' organizations for use at State or national conventions or for national youth, athletic,...

  14. 32 CFR 643.128 - Veterans' conventions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Veterans' conventions. 643.128 Section 643.128... ESTATE Additional Authority of Commanders § 643.128 Veterans' conventions. Without reference to higher... veterans' organizations for use at State or national conventions or for national youth, athletic,...

  15. Division Reports from the 2005 AECT Convention

    ERIC Educational Resources Information Center

    TechTrends: Linking Research & Practice to Improve Learning, 2006

    2006-01-01

    The Association for Educational Communication & Technology held its International Convention in Orlando, Florida, October 18-22, 2005. The convention theme was "Exploring the Vision". Division report highlights include: (1) Reflections on a Convention: A Vision Explored (Wes Miller); (2) Definition and Terminology Committee (Al Januszewski); (3)…

  16. Investigation on penetration model of shaped charge jet in water

    NASA Astrophysics Data System (ADS)

    Shi, Jinwei; Luo, Xingbai; Li, Jinming; Jiang, Jianwei

    2016-01-01

    To analyze the process of jet penetration in water medium quantitatively, the properties of jet penetration spaced target with water interlayer were studied through test and numerical simulation. Two theoretical models of jet penetration in water were proposed. The theoretical model 1 was established considering the impact of the shock wave, combined with the shock equation Rankine-Hugoniot and the virtual origin calculation method. The theoretical model 2 was obtained by fitting theoretical analysis and numerical simulation results. The effectiveness and universality of the two theoretical models were compared through the numerical simulation results. Both the models can reflect the relationship between the penetration velocity and the penetration distance in water well, and both the deviation and stability of theoretical model 1 are better than 2, the lower penetration velocity, and the larger deviation of the theoretical model 2. Therefore, the theoretical model 1 can reflect the properties of jet penetration in water effectively, and provide the reference of model simulation and theoretical research.

  17. Laboratory technique for simulation of projectile penetration into geological targets

    SciTech Connect

    Setchell, R.E.; Guzman, J.A.

    1983-01-01

    A new approach to laboratory-scale experiments on high-velocity penetration of projectiles into geological materials is demonstrated. This method utilizes a commercial accelerometer mounted within a small penetrator model that impacts a sample of target material. As in previous laboratory-scale experiments at high velocities, a compressed-gas gun is used in a reverse-ballistics configuration to accelerate a geological sample into an initially stationary penetrator. The present approach provides an acceleration history during the penetration, rather than displacement or velocity data as in these previous studies. Two experiments were conducted at each of two impact velocities using a conical-nosed penetrator and a simulated soft-sandstone target. The recorded accelerometer signals show high-frequency transducer resonances superimposed on the response expected for rigid-body acceleration. Direct numerical techniques are used to extract the rigid-body acceleration history. In addition to demonstrating the effectiveness of this approach, the present results provide useful information on how peak penetrator forces vary with impact velocity during conical-nosed penetration into the simulated sandstone.

  18. Sensitivity and comparison evaluation of Saturn 5 liquid penetrants

    NASA Technical Reports Server (NTRS)

    Jones, G. H.

    1973-01-01

    Results of a sensitivity and comparison evaluation performed on six liquid penetrants that were used on the Saturn 5 vehicle and other space hardware to detect surface discontinuities are described. The relationship between penetrant materials and crack definition capabilities, the optimum penetrant materials evaluation method, and the optimum measurement methods for crack dimensions were investigated. A unique method of precise developer thickness control was envolved, utilizing clear radiographic film and a densitometer. The method of evaluation included five aluminum alloy, 2219-T87, specimens that were heated and then quenched in cold water to produce cracks. The six penetrants were then applied, one at a time, and the crack indications were counted and recorded for each penetrant for comparison purposes. Measurements were made by determining the visual crack indications per linear inch and then sectioning the specimens for a metallographic count of the cracks present. This method provided a numerical approach for assigning a sensitivity index number to the penetrants. Of the six penetrants evaluated, two were not satisfactory (one was not sufficiently sensitive and the other was to sensitive, giving false indications). The other four were satisfactory with approximately the same sensitivity in the range of 78 to 80.5 percent of total cracks detected.

  19. Mechanism and determinants of nanoparticle penetration through human skin.

    PubMed

    Labouta, Hagar I; el-Khordagui, Labiba K; Kraus, Tobias; Schneider, Marc

    2011-12-01

    The ability of nanoparticles to penetrate the stratum corneum was the focus of several studies. Yet, there are controversial issues available for particle penetration due to different experimental setups. Meanwhile, there is little known about the mechanism and determinants of their penetration. In this paper the penetration of four model gold nanoparticles of diameter 6 and 15 nm, differing in surface polarity and the nature of the vehicle, through human skin was studied using multiphoton microscopy. This is in an attempt to profoundly investigate the parameters governing particle penetration through human skin. Our results imply that nanoparticles at this size range permeate the stratum corneum in a similar manner to drug molecules, mainly through the intercellular pathways. However, due to their particulate nature, permeation is also dependent on the complex microstructure of the stratum corneum with its tortuous aqueous and lipidic channels, as shown from our experiments performed using skin of different grades of barrier integrity. The vehicle (toluene-versus-water) had a minimal effect on skin penetration of gold nanoparticles. Other considerations in setting up a penetration experiment for nanoparticles were also studied. The results obtained are important for designing a new transdermal carrier and for a basic understanding of skin-nanoparticle interaction. PMID:22064944

  20. Mechanism and determinants of nanoparticle penetration through human skin

    NASA Astrophysics Data System (ADS)

    Labouta, Hagar I.; El-Khordagui, Labiba K.; Kraus, Tobias; Schneider, Marc

    2011-12-01

    The ability of nanoparticles to penetrate the stratum corneum was the focus of several studies. Yet, there are controversial issues available for particle penetration due to different experimental setups. Meanwhile, there is little known about the mechanism and determinants of their penetration. In this paper the penetration of four model gold nanoparticles of diameter 6 and 15 nm, differing in surface polarity and the nature of the vehicle, through human skin was studied using multiphoton microscopy. This is in an attempt to profoundly investigate the parameters governing particle penetration through human skin. Our results imply that nanoparticles at this size range permeate the stratum corneum in a similar manner to drug molecules, mainly through the intercellular pathways. However, due to their particulate nature, permeation is also dependent on the complex microstructure of the stratum corneum with its tortuous aqueous and lipidic channels, as shown from our experiments performed using skin of different grades of barrier integrity. The vehicle (toluene-versus-water) had a minimal effect on skin penetration of gold nanoparticles. Other considerations in setting up a penetration experiment for nanoparticles were also studied. The results obtained are important for designing a new transdermal carrier and for a basic understanding of skin-nanoparticle interaction.

  1. Proton Radiography of Shape Charge Jets Penetrating Teflon and Explosive

    NASA Astrophysics Data System (ADS)

    Ferm, Eric N.; Burkett, Michael W.; Hull, Larry M.; Marr-Lyon, Mark; McNeil, Wendy V.; Morris, Chris L.; Rightley, Paul M.; Lansce Proton Radiography Team

    2011-06-01

    We have used proton radiography at the Los Alamos Neutron Science Center to observe viper shaped charge jets penetrating inert and explosive materials. A viper jet was observed penetrating both Teflon and PBX 9501. Radiographs captured the penetration events at several times and are analyzed to determine the density of the materials imaged at each time. The interfaces and shock waves in the flow are clearly evident in the images. Multiple time images allow the determination of the velocities of the interfaces and shock waves. Comparisons are made in the Teflon case with estimates of penetration rates and densities using the quasi-steady approximation analysis used in many terminal ballistics models. The PBX 9501 clearly detonated from the impact of the shape charge jet tip traveling at 9.1 mm/s. The detonation wave is examined to see what support it obtains from the pursing jet and the jet is examined to find the influence of the explosive products on penetration velocity. This experiment gives us experimental results of in-situ penetration process that can be used to verify common modeling techniques and fluid mechanic calculations of the penetration process.

  2. Cell-penetrating peptides transport therapeutics into cells.

    PubMed

    Ramsey, Joshua D; Flynn, Nicholas H

    2015-10-01

    Nearly 30years ago, certain small, relatively nontoxic peptides were discovered to be capable of traversing the cell membrane. These cell-penetrating peptides, as they are now called, have been shown to not only be capable of crossing the cell membrane themselves but can also carry many different therapeutic agents into cells, including small molecules, plasmid DNA, siRNA, therapeutic proteins, viruses, imaging agents, and other various nanoparticles. Many cell-penetrating peptides have been derived from natural proteins, but several other cell-penetrating peptides have been developed that are either chimeric or completely synthetic. How cell-penetrating peptides are internalized into cells has been a topic of debate, with some peptides seemingly entering cells through an endocytic mechanism and others by directly penetrating the cell membrane. Although the entry mechanism is still not entirely understood, it seems to be dependent on the peptide type, the peptide concentration, the cargo the peptide transports, and the cell type tested. With new intracellular disease targets being discovered, cell-penetrating peptides offer an exciting approach for delivering drugs to these intracellular targets. There are hundreds of cell-penetrating peptides being studied for drug delivery, and ongoing studies are demonstrating their success both in vitro and in vivo. PMID:26210404

  3. Counselling framework for moderate-penetrance cancer-susceptibility mutations.

    PubMed

    Tung, Nadine; Domchek, Susan M; Stadler, Zsofia; Nathanson, Katherine L; Couch, Fergus; Garber, Judy E; Offit, Kenneth; Robson, Mark E

    2016-09-01

    The use of multigene panels for the assessment of cancer susceptibility is expanding rapidly in clinical practice, particularly in the USA, despite concerns regarding the uncertain clinical validity for some gene variants and the uncertain clinical utility of most multigene panels. So-called 'moderate-penetrance' gene mutations associated with cancer susceptibility are identified in approximately 2-5% of individuals referred for clinical testing; some of these mutations are potentially actionable. Nevertheless, the appropriate management of individuals harbouring such moderate-penetrance genetic variants is unclear. The cancer risks associated with mutations in moderate-penetrance genes are lower and different than those reported for high-penetrance gene mutations (such as mutations in BRCA1 and BRCA2, and those associated with Lynch syndrome). The extrapolation of guidelines for the management of individuals with high-penetrance variants of cancer-susceptibility genes to the clinical care of patients with moderate-penetrance gene mutations could result in substantial harm. Thus, we provide a framework for clinical decision-making pending the development of a sufficient evidence base to document the clinical utility of the interventions for individuals with inherited moderate-penetrance gene mutations associated with an increased risk of cancer. PMID:27296296

  4. Penetration of the LCLS Injector Shield Wall at Sector 20

    SciTech Connect

    Dowell, D

    2010-12-10

    Penetrations through the LCLS injector shield wall are needed for the alignment of the accelerator, a diagnostic laser beam and utilities, and are shown in figure 1. The 1-inch diameter LCLS injector beam tube is blocked by the PPS stopper when the injector side of the wall is occupied. The two 3-inch diameter penetrations above and to the left of the beam tube are used by Precision Alignment and will be open only during installation of the injector beamline. Additional 3-inch diameter penetrations are for laser beams which will be used for electron beam diagnostics. These will not be plugged when the injector occupied. Other penetrations for the RF waveguide and other utilities are approximately 13-inch from the floor and as such are far from the line-of-sight of any radiation sources. The waveguide and utility penetrations pass only through the thicker wall as shown in the figure. The principal issue is with the two laser penetrations, since these will be open when the linac is operating and people are in the LCLS injector area. A principal concern is radiation streaming through the penetrations due to direct line-of sight of the PEP-2 lines. To answer this, fans of rays were traced through the 3-inch diameter laser penetrations as shown in Figures 2 and 3. Figure 2 gives the top view of the shield walls, the main linac and PEP-2 lines, and the ray-fans. The fans appear to originate between the walls since their angular envelope is defined by the greatest angle possible when rays are just on the 3-inch diameter at the inner most and outermost wall surfaces. The crossovers of all possible rays lie half way between these two surfaces. As the end-on view of Figure 3 clearly shows, there is no direct line-of-sight through the laser penetrations of the PEP-2 or linac beamlines.

  5. THE KINETICS OF PENETRATION : VIII. TEMPORARY ACCUMULATION.

    PubMed

    Osterhout, W J; Kamerling, S E

    1934-03-20

    A model is described which throws light on the mechanism of accumulation. In the model used an external aqueous phase A is separated by a non-aqueous phase B (representing the protoplasm) from the artificial sap in C. A contains KOH and C contains HCl: they tend to mix by passing through the non-aqueous layer but much more KOH moves so that most of the KCl is formed in C, where the concentration of potassium becomes much greater than in A. This accumulation is only temporary for as the system approaches equilibrium the composition of A approaches identity with that of C, since all the substances present can pass through the non-aqueous layer. Such an approach to equilibrium may be compared to the death of the cell as the result of which accumulation disappears. During the earlier stages of the experiment potassium tends to go in as KOH and at the same time to go out as KCl. These opposing tendencies do not balance until the concentration of potassium inside becomes much greater than outside (hence potassium accumulates). The reason is that KCl, although its driving force be great, moves very slowly in B because its partition coefficient is low and in consequence its concentration gradient in B is small. This illustrates the importance of partition coefficients for penetration in models and in living cells. It also indicates that accumulation depends on the fact that permeability is greater for the ingoing compound of the accumulating substance than for the outgoing compound. Other things being equal, accumulation is increased by maintaining a low pH in C. Hence we may infer that anything which checks the production of acid in the living cell may be expected to check accumulation and growth. This model recalls the situation in Valonia and in most living cells where potassium accumulates as KCl, perhaps because it enters as KOH and forms KA in the sap (where A is an organic anion). In some plants potassium accumulates as KA but when HCl exists in the external

  6. Numerical Modelling of Ground Penetrating Radar Antennas

    NASA Astrophysics Data System (ADS)

    Giannakis, Iraklis; Giannopoulos, Antonios; Pajewski, Lara

    2014-05-01

    Numerical methods are needed in order to solve Maxwell's equations in complicated and realistic problems. Over the years a number of numerical methods have been developed to do so. Amongst them the most popular are the finite element, finite difference implicit techniques, frequency domain solution of Helmontz equation, the method of moments, transmission line matrix method. However, the finite-difference time-domain method (FDTD) is considered to be one of the most attractive choice basically because of its simplicity, speed and accuracy. FDTD first introduced in 1966 by Kane Yee. Since then, FDTD has been established and developed to be a very rigorous and well defined numerical method for solving Maxwell's equations. The order characteristics, accuracy and limitations are rigorously and mathematically defined. This makes FDTD reliable and easy to use. Numerical modelling of Ground Penetrating Radar (GPR) is a very useful tool which can be used in order to give us insight into the scattering mechanisms and can also be used as an alternative approach to aid data interpretation. Numerical modelling has been used in a wide range of GPR applications including archeology, geophysics, forensic, landmine detection etc. In engineering, some applications of numerical modelling include the estimation of the effectiveness of GPR to detect voids in bridges, to detect metal bars in concrete, to estimate shielding effectiveness etc. The main challenges in numerical modelling of GPR for engineering applications are A) the implementation of the dielectric properties of the media (soils, concrete etc.) in a realistic way, B) the implementation of the geometry of the media (soils inhomogeneities, rough surface, vegetation, concrete features like fractures and rock fragments etc.) and C) the detailed modelling of the antenna units. The main focus of this work (which is part of the COST Action TU1208) is the accurate and realistic implementation of GPR antenna units into the FDTD

  7. Transorbital Orbitocranial Penetrating Injury with an Iron Rod.

    PubMed

    Agrawal, Amit; Reddy, V Umamaheswara; Kumar, S Satish; Hegde, Kishor V; Rao, G Malleswara

    2016-06-01

    Transorbital orbitocranial penetrating injuries (TOPIs) are relatively rare, can be caused by high-speed projectile foreign bodies to low-energy trauma (which is rarer), and account for 24% of penetrating head injuries in adults and approximately 45% in children. We report an uncommon nonfatal case of TOPI where a 16-year-old male child sustained injury due to accidental penetration of metal bar into the forehead. A bicoronal flap was raised to remove the metal bar. The patient recovered well, had normal vision, and doing well at follow-up. PMID:27162571

  8. Penetration into limestone targets with ogive-nose steel projectiles

    SciTech Connect

    Frew, D.J.; Green, M.L.; Forrestal, M.J.; Hanchak, S.J.

    1996-12-01

    We conducted depth of penetration experiments into limestone targets with 3.0 caliber-radius-head, 4340 Rc 45 steel projectiles. Powder guns launched two projectiles with length-to-diameter ratios of ten to striking velocities between 0.4 and 1.5 km/s. Projectiles had diameters and masses of 12.7 mm, 0. 117 kg and 25.4 mm, 0.610 kg. Based on data sets with these two projectile scales, we proposed an empirical penetration equation that described the target by its density and an empirical strength constant determined from penetration depth versus striking velocity data.

  9. Penetrating facial injury with an "Airsoft" pellet: a case report.

    PubMed

    Strong, Ben; Coady, Martin

    2014-11-01

    Airsoft is a recreational combat sport that originated in Japan in the 1970s and is currently increasing in popularity in the UK. Participants use air or electrically powered weapons to fire small plastic pellets at a controlled pressure. UK law strictly regulates the maximum muzzle velocity and the type of ammunition used in these weapons. A search of published papers found several reports of penetrating ocular injuries caused by Airsoft pellets, but no reports of penetrating injuries to other areas of the body. We report the case of a 25-year-old man who sustained a penetrating injury to the cheek after being shot with an Airsoft weapon. PMID:24930055

  10. Investigations of impact biomechanics for penetrating ballistic cases.

    PubMed

    Awoukeng-Goumtcha, A; Taddei, L; Tostain, F; Roth, S

    2014-01-01

    This study aims to investigate the penetration of a projectile into a surrogate human tissue numerically, using Finite Element (FE) simulation. 20% Balistic Gelatin material (BG) is simulated with an elasto-plastic hydrodynamic constitutive law, and then impacted by steel spheres at different velocities. The results from the FE simulations are compared with existing experimental data and other analytical equations from the literature. To our knowledge, this is the first study to investigate a projectile penetration by numerical simulation, and then compare the results with analytical and experimental data from previous studies. This developed model gives encouraging results for further investigations of penetrating impact of projectile in the human body. PMID:25226933

  11. Toroidal modeling of penetration of the resonant magnetic perturbation field

    SciTech Connect

    Liu Yueqiang; Kirk, A.

    2013-04-15

    A toroidal, quasi-linear model is proposed to study the penetration dynamics of the resonant magnetic perturbation (RMP) field into the plasma. The model couples the linear, fluid plasma response to a toroidal momentum balance equation, which includes torques induced by both fluid electromagnetic force and by (kinetic) neoclassical toroidal viscous (NTV) force. The numerical results for a test toroidal equilibrium quantify the effects of various physical parameters on the field penetration and on the plasma rotation braking. The neoclassical toroidal viscous torque plays a dominant role in certain region of the plasma, for the RMP penetration problem considered in this work.

  12. Penetrating Trauma to the Ureter, Bladder, and Urethra

    PubMed Central

    Zaid, Uwais B.; Bayne, David B.; Harris, Catherine R.; Alwaal, Amjad; McAninch, Jack W.; Breyer, Benjamin N.

    2015-01-01

    We describe the epidemiology, diagnosis, and management of adult civilian penetrating trauma to the ureter, bladder, and urethra. Trauma is a significant source of death and morbidity. Genitourinary injuries are present in 10% of penetrating trauma cases. Prompt recognition and appropriate management of genitourinary injuries, which are often masked or overlooked due to concomitant injuries, is essential to minimize morbidity. Penetrating trauma most commonly results from gunshot wounds or stab wounds. Compared to blunt trauma, these typically require surgical exploration. An understanding of anatomy and a high index of suspicion are necessary for prompt recognition of genitourinary injuries. PMID:26623247

  13. Generating penetration path hypotheses for decision support in multiple trauma.

    PubMed Central

    Ogunyemi, O.; Kaye, J.; Webber, B.; Clarke, J. R.

    1995-01-01

    We present a 3D graphical system that allows users to visualize different penetration path hypotheses for (multiple) gunshot or stab wounds, using a 3D graphical model of a human body with appropriate anatomical structures. The system also identifies the anatomical structures associated with each hypothesis. The various penetration path hypotheses follow from a combinatorial analysis of the set of surface wounds. The affected structures are determined by performing a detailed interpenetration analysis between 3D models of a penetration path and each anatomical structure within the body. Images Figure 2 Figure 3 PMID:8563315

  14. The effect of the Rim Cutter on cement pressurization and penetration on cemented acetabular fixation in total hip arthroplasty: an in vitro study.

    PubMed

    Smith, B N; Lee, A J C; Timperley, A J; Whitehouse, S L; Crawford, R W

    2010-01-01

    The Rim Cutter (Stryker Orthopedics, Mahwah, New Jersey) is a tool designed to cut a ledge inside the rim of the acetabulum, onto which a precisely trimmed, cemented, flanged cup can be fitted. The aim was to investigate the effect of the Rim Cutter on the intra-acetabular cement mantle pressure and the depth of cement penetration during cup insertion. The study had two parts. In the first part, hemi-pelvis models were fitted with pressure sensors. Pressure in the acetabulum was measured on insertion of a conventional cemented flanged cup with and without the use of a Rim Cutter to prepare the rim of the acetabulum. The second part assessed cement penetration when the same cups were inserted into a foam shell model. The shell was mounted in a jig and had holes drilled in it; the distance that cement penetrated into the holes was measured. A significant increase in cement pressure at the apex (p = 0.04) and the rim (p = 0.004) is seen when the Rim Cutter is used. Cement penetration in the Rim Cutter group was significantly increased at the rim of the acetabulum (p = 0.003). Insertion of a flanged cup after the acetabulum is prepared with the Rim Cutter leads to a significant increase in cement pressure and penetration during cup insertion in vitro when compared with conventional flanged cups. PMID:21053777

  15. Time delay of interplanetary magnetic field penetration into Earth's magnetotail

    NASA Astrophysics Data System (ADS)

    Rong, Z. J.; Lui, A. T. Y.; Wan, W. X.; Yang, Y. Y.; Shen, C.; Petrukovich, A. A.; Zhang, Y. C.; Zhang, T. L.; Wei, Y.

    2015-05-01

    Many previous studies have demonstrated that the interplanetary magnetic field (IMF) can control the magnetospheric dynamics. Immediate magnetospheric responses to the external IMF have been assumed for a long time. The specific processes by which IMF penetrates into magnetosphere, however, are actually unclear. Solving this issue will help to accurately interpret the time sequence of magnetospheric activities (e.g., substorm and tail plasmoids) exerted by IMF. With two carefully selected cases, we found that the penetration of IMF into magnetotail is actually delayed by 1-1.5 h, which significantly lags behind the magnetotail response to the solar wind dynamic pressure. The delayed time appears to vary with different auroral convection intensity, which may suggest that IMF penetration in the magnetotail is controlled considerably by the dayside reconnection. Several unfavorable cases demonstrate that the penetration lag time is more clearly identified when storm/substorm activities are not involved.

  16. Simple Amides of Oleanolic Acid as Effective Penetration Enhancers

    PubMed Central

    Bednarczyk-Cwynar, Barbara; Partyka, Danuta; Zaprutko, Lucjusz

    2015-01-01

    Transdermal transport is now becoming one of the most convenient and safe pathways for drug delivery. In some cases it is necessary to use skin penetration enhancers in order to allow for the transdermal transport of drugs that are otherwise insufficiently skin-permeable. A series of oleanolic acid amides as potential transdermal penetration enhancers was formed by multistep synthesis and the synthesis of all newly prepared compounds is presented. The synthetized amides of oleanolic acid were tested for their in vitro penetration promoter activity. The above activity was evaluated by means of using the Fürst method. The relationships between the chemical structure of the studied compounds and penetration activity are presented. PMID:26010090

  17. Subungual penetration of dibutyl phthalate in human fingernails.

    PubMed

    Jackson, E M

    2008-01-01

    Dibutyl phthalate (DBP) has a wide variety of manufacturing applications and is used in both commercial and consumer products. Results of animal reproductive toxicity and teratogenicity animal studies have not been consistent in identifying DBP as a reproductive toxicant. Expert reviews for its use in consumer products have consistently concluded that it is not a reproductive risk to consumers. Results from a subungual penetration study of 100% fluid DBP applied to human fingernails showed levels of penetration at the limits of chemical detection. Even if DBP penetrated the human fingernail, its rapid metabolism by the human body would prevent its having any toxic reproductive effects. Furthermore, DBP functions as a plasticizer in consumer products such as cosmetic nail products (nail polish, basecoats, topcoats, nail hardeners), resulting in its becoming unavailable for subungual penetration seconds after application of the cosmetic nail product since it is then trapped in the rapidly forming coating. PMID:17912019

  18. Zn Penetration in Liquid Metal Embrittled TWIP Steel

    NASA Astrophysics Data System (ADS)

    Kang, Heeseung; Cho, Lawrence; Lee, Changwook; De Cooman, Bruno C.

    2016-06-01

    Hot-dip Zn-coated high manganese twinning-induced plasticity (TWIP) steel is sensitive to liquid metal embrittlement (LME). The microstructure of Zn-coated TWIP steel after brittle fracture at 1123 K (850 °C) was investigated. The grain boundaries at the tip of the Zn penetration were analyzed by electron microscopy and atom probe tomography. Γ-(Fe,Mn)3Zn10 was found at the tip of the Zn penetration in the TWIP steel, implying that liquid Fe- and Mn-saturated Zn-rich alloy had percolated along the grain boundaries to the tip of the Zn penetration. Evidence for extensive Zn grain boundary diffusion ahead of the Zn-rich alloy percolation path was also observed. Both the Stoloff-Johnson-Westwood-Kamdar model and the Krishtal-Gordon-An model for LME crack formation are compatible with the present in-depth microanalysis of the Zn penetration.

  19. Overview of foliage/ground penetration and interferometric SAR experiments

    NASA Astrophysics Data System (ADS)

    Giglio, Dominick A.

    1994-06-01

    This paper describes foliage/ground-penetration radar experiments and interferometric synthetic aperture radar experiments sponsored by the Advanced Research Projects Agency in 1992-3. In the foliage/ground penetration experiments, airborne synthetic aperture radar data have been collected at a variety of sites in three bands, 20-90 MHz, 100-500 MHz, and 1200-1300 MHz. Foliage penetration data were collected on Panamanian rain forest and on Northern Maine woods, and ground penetration data were collected on buried objects in a desert site in Arizona. Interferometric SAR data have been collected on various terrain to extract terrain height, and on military vehicles such as tanks and trucks to assess the utility of height information for target detection and recognition.

  20. Penetration analysis of projectile with inclined concrete target

    NASA Astrophysics Data System (ADS)

    Kim, S. B.; Kim, H. W.; Yoo, Y. H.

    2015-09-01

    This paper presents numerical analysis result of projectile penetration with concrete target. We applied dynamic material properties of 4340 steels, aluminium and explosive for projectile body. Dynamic material properties were measured with static tensile testing machine and Hopkinson pressure bar tests. Moreover, we used three concrete damage models included in LS-DYNA 3D, such as SOIL_CONCRETE, CSCM (cap model with smooth interaction) and CONCRETE_DAMAGE (K&C concrete) models. Strain rate effect for concrete material is important to predict the fracture deformation and shape of concrete, and penetration depth for projectiles. CONCRETE_DAMAGE model with strain rate effect also applied to penetration analysis. Analysis result with CSCM model shows good agreement with penetration experimental data. The projectile trace and fracture shapes of concrete target were compared with experimental data.

  1. Ten self-inflicted intracranial penetrating nail gun injuries

    PubMed Central

    Yuh, Sung-Joo; Alaqeel, Ahmed

    2015-01-01

    Penetrating craniocerebral injuries from nail gun use are rare. We describe a case of 10 self-inflicted nail gun injuries with intracranial penetrations. We also review the literature and discuss management strategies of such craniocerebral trauma. A 33-year-old male with a long-standing history of severe depression took a nail gun and sustained 10 penetrating intracranial injuries. Initial neuroimaging revealed 10 penetrating nails, all sparing the major cerebral vasculature. Immediate surgical removal was undertaken in the surgical suite using a combination of craniotomies, craniectomies, and blind removal. Intracranial injuries from self-inflicted nail gun misuse is becoming increasingly more frequent. Initial appropriate clinical decision-making are critical in preventing further cortical or vascular damage. PMID:26166596

  2. Neuropsychiatric changes following penetrating head injury in children

    PubMed Central

    Badhiwala, Jetan H.; Blackham, Janet R.; Bhardwaj, Ratan D.

    2014-01-01

    Background: Penetrating head injuries demand the prompt attention of a neurosurgeon. While most neurosurgical centers are experienced in the acute management of these injuries, less is known about the long-term neuropsychiatric sequelae of penetrating head trauma. In adults, direct injury to the frontal lobe classically has been associated with mental status changes. However, there is less published data in children. Case Description: We report the case of a 12-year-old boy who suffered a penetrating head injury to the frontal lobes secondary to a self-inflicted gunshot wound, and experienced subsequent resolution of pre-existing bipolar disorder and new onset of attention deficit hyperactivity disorder. Conclusion: Children with penetrating head injury require close multidisciplinary follow-up in order to monitor, and accordingly implement management strategies, for associated sequelae, including behavioral and neuropsychiatric changes. PMID:25422782

  3. Transmission System Performance Analysis for High-Penetration Photovoltaics

    SciTech Connect

    Achilles, S.; Schramm, S.; Bebic, J.

    2008-02-01

    This study is an assessment of the potential impact of high levels of penetration of photovoltaic (PV) generation on transmission systems. The effort used stability simulations of a transmission system with different levels of PV generation and load.

  4. Age-related percutaneous penetration part 1: skin factors.

    PubMed

    Konda, S; Meier-Davis, S R; Cayme, B; Shudo, J; Maibach, H I

    2012-05-01

    Changes in the skin that occur in the elderly may put them at increased risk for altered percutaneous penetration from pharmacotherapy along with potential adverse effects. Skin factors that may have a role in age-related percutaneous penetration include blood flow, pH, skin thickness, hair and pore density, and the content and structure of proteins, glycosaminoglycans (GAGs), water, and lipids. Each factor is examined as a function of increasing age along with its potential impact on percutaneous penetration. Additionally, topical drugs that successfully overcome the barrier function of the skin can still fall victim to cutaneous metabolism, thereby producing metabolites that may have increased or decreased activity. This overview discusses the current data and highlights the importance of further studies to evaluate the impact of skin factors in age-related percutaneous penetration. PMID:22622279

  5. Space station integrated wall design and penetration damage control

    NASA Technical Reports Server (NTRS)

    Coronado, A. R.; Gibbins, M. N.; Wright, M. A.; Stern, P. H.

    1987-01-01

    A methodology was developed to allow a designer to optimize the pressure wall, insulation, and meteoroid/debris shield system of a manned spacecraft for a given spacecraft configuration and threat environment. The threat environment consists of meteoroids and orbital debris, as specified for an arbitrary orbit and expected lifetime. An overall probability of no penetration is calculated, as well as contours of equal threat that take into account spacecraft geometry and orientation. Techniques, tools, and procedures for repairing an impacted and penetrated pressure wall were developed and tested. These techniques are applied from the spacecraft interior and account for the possibility of performing the repair in a vacuum. Hypervelocity impact testing was conducted to: (1) develop and refine appropriate penetration functions, and (2) determine the internal effects of a penetration on personnel and equipment.

  6. Urgent Intracranial Carotid Artery Decompression after Penetrating Head Injury

    PubMed Central

    Kim, Seong Joon

    2013-01-01

    We describe a case of intracranial carotid artery occlusion due to penetrating craniofacial injury by high velocity foreign body that was relieved by decompressive surgery. A 46-year-old man presented with a penetrating wound to his face. A piece of an electric angular grinder disc became lodged in the anterior skull base. Computed tomography revealed that the disc had penetrated the unilateral paraclinoid and suprasellar areas without flow of the intracranial carotid artery on the lesion side. The cavernous sinus was also compromised. Removal of the anterior clinoid process reopened the carotid blood flow, and the injection of glue into the cavernous sinus restored complete hemostasis during extraction of the fragment from the face. Digital subtraction angiography revealed complete recanalization of the carotid artery without any evidence of dissection. Accurate diagnosis regarding the extent of the compromised structures and urgent decompressive surgery with adequate hemostasis minimized the severity of penetrating damage in our patient. PMID:23634269

  7. Probabilistic simulation for flaw acceptance by dye-penetrant inspection

    NASA Technical Reports Server (NTRS)

    Russell, D. A.; Keremes, J. J.

    1990-01-01

    This paper examines the problems encountered in assessing the reliability of dye-penetrant nondestructive inspection (NDI) techniques in preventing failures due to undetected surface flaws, as well as from flaw acceptance (Fitness-For-Purpose). A Monte Carlo simulation procedure which includes the major variables of the problem is presented as a means of quantifying reliability. Some issues associated with distribution selection are examined. A methodology for selecting the penetrant type and flaw acceptance size for the specific components analyzed using the simulation is proposed. Current methodology limitations are discussed along with possible future effort. Penetrant selection and acceptable sizes of detected flaws are based on a probabilistic assessment of the effect of component and dye-penetrant system variables on structural reliability.

  8. Zn Penetration in Liquid Metal Embrittled TWIP Steel

    NASA Astrophysics Data System (ADS)

    Kang, Heeseung; Cho, Lawrence; Lee, Changwook; De Cooman, Bruno C.

    2016-04-01

    Hot-dip Zn-coated high manganese twinning-induced plasticity (TWIP) steel is sensitive to liquid metal embrittlement (LME). The microstructure of Zn-coated TWIP steel after brittle fracture at 1123 K (850 °C) was investigated. The grain boundaries at the tip of the Zn penetration were analyzed by electron microscopy and atom probe tomography. Γ-(Fe,Mn)3Zn10 was found at the tip of the Zn penetration in the TWIP steel, implying that liquid Fe- and Mn-saturated Zn-rich alloy had percolated along the grain boundaries to the tip of the Zn penetration. Evidence for extensive Zn grain boundary diffusion ahead of the Zn-rich alloy percolation path was also observed. Both the Stoloff-Johnson-Westwood-Kamdar model and the Krishtal-Gordon-An model for LME crack formation are compatible with the present in-depth microanalysis of the Zn penetration.

  9. Evidence of effective penetration of Listeria monocytogenes biofilms by disinfectant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The generation of protective biofilms by microorganisms that aggregate on food processing equipment surfaces is a major contributing factor to contamination and disinfection failure in meat and poultry processing facilities. Traditional disinfectants and cleaners do not effectively penetrate the bi...

  10. Maximum Photovoltaic Penetration Levels on Typical Distribution Feeders: Preprint

    SciTech Connect

    Hoke, A.; Butler, R.; Hambrick, J.; Kroposki, B.

    2012-07-01

    This paper presents simulation results for a taxonomy of typical distribution feeders with various levels of photovoltaic (PV) penetration. For each of the 16 feeders simulated, the maximum PV penetration that did not result in steady-state voltage or current violation is presented for several PV location scenarios: clustered near the feeder source, clustered near the midpoint of the feeder, clustered near the end of the feeder, randomly located, and evenly distributed. In addition, the maximum level of PV is presented for single, large PV systems at each location. Maximum PV penetration was determined by requiring that feeder voltages stay within ANSI Range A and that feeder currents stay within the ranges determined by overcurrent protection devices. Simulations were run in GridLAB-D using hourly time steps over a year with randomized load profiles based on utility data and typical meteorological year weather data. For 86% of the cases simulated, maximum PV penetration was at least 30% of peak load.

  11. Geometry-dependent penetration fields in superconducting Bi2Sr2CaCu2O8+δ platelets

    SciTech Connect

    By: Curran, P. J.; Clem, J. R.; Bending, S. J.; Tsuchiya, Y.; Tamegai, T.

    2010-10-01

    Magneto-optical imaging has been used to study vortex penetration into regular polygon-shaped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} platelets with various geometries (disks, pentagons, squares, and triangles) but known fixed areas. In all cases we observe an exponential dependence of the field of first penetration, H{sub p}, on temperature, consistent with a dominant Bean-Livingston barrier for pancake vortices at our measurement temperatures (45-80 K). However, the penetration field consistently decreases with decreasing degree of sample symmetry, in stark contrast to conventional estimates of demagnetization factors using equivalent ellipsoids based on inscribed circles, which predict the reverse trend. Surprisingly, this observation does not appear to have been reported in the literature before. We demonstrate empirically that estimates using equivalent ellipsoids based on circumscribed circles predict the correct qualitative experimental trend in H{sub p}. Our work has important implications for the estimation of appropriate effective demagnetization factors for flux penetration into arbitrarily shaped superconducting bodies.

  12. Geometry-dependent penetration fields of superconducting Bi2Sr2CaCu2O8+δ platelets

    SciTech Connect

    Curran, P. J.; Clem, J. R.; Bending, S. J.; Tsuchiya, Y.; Tamegai, T.

    2010-10-01

    Magneto-optical imaging has been used to study vortex penetration into regular polygon-shaped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} platelets with various geometries (disks, pentagons, squares, and triangles) but known fixed areas. In all cases we observe an exponential dependence of the field of first penetration, H{sub p}, on temperature, consistent with a dominant Bean-Livingston barrier for pancake vortices at our measurement temperatures (45-80 K). However, the penetration field consistently decreases with decreasing degree of sample symmetry, in stark contrast to conventional estimates of demagnetization factors using equivalent ellipsoids based on inscribed circles, which predict the reverse trend. Surprisingly, this observation does not appear to have been reported in the literature before. We demonstrate empirically that estimates using equivalent ellipsoids based on circumscribed circles predict the correct qualitative experimental trend in Hp. Our work has important implications for the estimation of appropriate effective demagnetization factors for flux penetration into arbitrarily shaped superconducting bodies.

  13. Development and testing of a Europa Penetrator for Astrobiology

    NASA Astrophysics Data System (ADS)

    Vijendran, S.; Perkinson, M.-C.; Waugh, L.; Ratcliffe, A.; Kennedy, T.; Church, P.; Fielding, J.; Taylor, N.

    2014-04-01

    Two phases of Penetrator development activities have been funded by ESA. The first phase focussed on the mission and system definition of a penetrator and delivery system for a mission to Europa and the second phase provided an update of the penetrator design for a larger suite of instruments focused on astrobiology and the demonstration of key system technologies through a programme of small scale and full scale testing. The science focus for the Europa penetrator is Astrobiology while the key science goals can be achieved within the first day of operation but a longer lifetime is required for the transmission of the science data to the orbiter. The extreme temperature environment of the Europan surface drove the design to a solution of a Penetrator with two separate bays. The front bay will be a short lifetime bay which will sample the surface and complete all analysis and data transfer within 10 hours. The rear bay is a warm bay which will house EPSC Abstracts Vol. 9, EPSC2014-642, 2014 European Planetary Science Congress 2014 c Author(s) 2014 EPSC European Planetary Science Congress the penetrator support systems required to transmit all collected data to the orbiter. The scientific instruments housed by the penetrator includeds a optical microimager, a habitability package and a mass spectrometer. A drilling and sampling mechanism is used for accessing the icy material outside the Penetrator for analysis. Small scale trails have been undertaken at the University of Cambridge Cavendish Laboratory to validate the impact modelling techniques and the robustness of critical components. A range of trials have been carried out to assess survivability of key elements of the design, including the sampling mechanism, potting compounds, accelerometers, shell, batteries and Torlon suspension springs. Full scale trials have been carried out to test the overall structural integrity of the system and the penetration profile. This programme was carried out in June 2013 at the

  14. Comparing the shear strength of grouted fractures: conventional methods vs biomineralisation

    NASA Astrophysics Data System (ADS)

    El Mountassir, G.; Tobler, D. J.; Moir, H.; Lunn, R. J.; Phoenix, V. R.

    2011-12-01

    For many engineering applications, such as geological disposal of nuclear waste, underground railways etc., it is necessary to limit fluid flow through fractures. The particle size of conventional cementitious grouts limits the size of fractures into which they can penetrate. To address this issue increasingly microfine and ultrafine cement grouts are becoming commercially available. Despite this the radius of penetration remains dependent on the grout viscosity alongside injection pressure, pumping rate, grout setting time and grout cohesion. As such lower viscosity aqueous solutions may have a greater radius of penetration potentially requiring fewer injection points. In addition cementitious grouts typically undergo volumetric shrinkage during setting. In many applications this change in volume may not be of particular importance but in others where a very low hydraulic conductivity is a critical design criterion, as in nuclear waste repositories, this reduction in volume may be highly significant. This study investigates the use of microbially induced carbonate precipitation (MCP) as a technique for grouting fine aperture rock fractures. Artificial fractures were created in granite cores and were subjected to conventional cementitious grouting methods and MCP. Following treatment the hydraulic and mechanical properties of the grouted fractures were investigated. The mechanical properties of grouts after setting is not usually considered to be a significant issue, but in applications which consider much longer timescales (100,000 years) grouts which result in fractures with improved strength and lower hydraulic conductivity are likely to be preferred.

  15. Solar energy market penetration models - Science or number mysticism

    NASA Technical Reports Server (NTRS)

    Warren, E. H., Jr.

    1980-01-01

    The forecast market potential of a solar technology is an important factor determining its R&D funding. Since solar energy market penetration models are the method used to forecast market potential, they have a pivotal role in a solar technology's development. This paper critiques the applicability of the most common solar energy market penetration models. It is argued that the assumptions underlying the foundations of rigorously developed models, or the absence of a reasonable foundation for the remaining models, restrict their applicability.

  16. Gastric ulcer penetrating to liver diagnosed by endoscopic biopsy

    PubMed Central

    Kayacetin, Ertugrul; Kayacetin, Serra

    2004-01-01

    Liver penetration is a rare but serious complication of peptic ulcer disease. Usually the diagnosis is made by operation or autopsy. Clinical and laboratory data were no specific. A 64-year-old man was admitted with upper gastrointestinal bleeding. Hepatic penetration was diagnosed as the cause of bleeding. Endoscopy showed a large gastric ulcer with a pseudotumoral mass protruding from the ulcer bed. Definitive diagnosis was established by endoscopic biopsies of the ulcer base. PMID:15188520

  17. Evaluation of percutaneous penetration of natural rubber latex proteins.

    PubMed

    Hayes, B B; Afshari, A; Millecchia, L; Willard, P A; Povoski, S P; Meade, B J

    2000-08-01

    Latex allergy is recognized worldwide as a serious health risk. To date, exposure assessment and intervention strategies have focused primarily on respiratory protection; this work evaluates the potential role of dermal protein penetration in the development of latex allergy. In vitro penetration models using flow-through diffusion cells and both human surgical specimens and hairless guinea pig skin (CrL: IAF/HA) demonstrated iodinated latex proteins (ammoniated and non-ammoniated) penetrating into and through both intact and abraded skin. Although less than 1% penetration was observed with intact skin, up to 23% of latex proteins applied to abraded skin were recovered from receptor fluid within 24 h of exposure. Phosphoimaging of the concentrated effluent revealed proteins ranging in size from 3 to 26 kDa. Using a (3)H(2)O penetration assay to evaluate barrier integrity, the amount of latex protein penetration was found to positively correlate with the degree of dermabrasion. Immunohistochemistry of the skin localized latex proteins in the Langerhans cell-rich epidermis and in the dermis. Both in vitro penetration studies and immunohistochemistry supported the use of hairless guinea pig skin as a surrogate for human skin in evaluating latex protein penetration. In studies performed in vivo, 35% of hairless guinea pigs topically exposed to latex proteins (100 microg) 5 days per week for 3 months demonstrated elevations in latex-specific IgG1. The implication for these data is that the skin is not only a plausible route for latex sensitization but can be a major exposure route when the integument has been compromised. PMID:10910983

  18. Penetrating nontorso trauma: the head and the neck

    PubMed Central

    Ball, Chad G.

    2015-01-01

    Summary Acute penetrating injuries to the head and neck cause considerable anxiety for most clinicians owing to concern for airway control and neurologic injury and to limited clinician experience in most centres. This article discusses an organized approach to the evaluation and initial treatment of penetrating injuries to the head and neck based on regional anatomy and clinical examination. The approach is particularly helpful in the context of ongoing hemorrhage and/or airway compromise. PMID:26022154

  19. Effect of DOP heterodispersion on HEPA-filter-penetration measurements

    SciTech Connect

    Bergman, W.; Biermann, A.

    1984-08-09

    The accuracy of the standard US test method for certifying High-Efficiency Particulate Air (HEPA) filters has been in question since the finding by Hinds, et al. that the dioctyl phthalate (DOP) aerosol used in the test is not monodisperse as had been assumed and that particle-size analyzers, or owls, could not distinguish between different particle-size distributions with the same owl reading. We have studied theoretically and experimentally the filter efficiency for different DOP size distributions with the same owl reading. Our studies show that the effect of varying DOP size distributions on the measured HEPA-filter penetration depends on the light-scattering-photometer response and on the HEPA-filter penetration curve, both measured as a function of particle size. HEPA-filter penetration for a heterodisperse DOP aerosol may be increased, decreased, or remain the same when compared to the filter penetration for monodisperse aerosols. Using experimental HEPA-filter penetration and photometer response curves, we show that heterodisperse DOP aerosols (D/sub cmd/ 0.19 and sigma g = 1.4) yield 24% lower penetrations than that for monodisperse DOP aerosols (D/sub cmd/ = 0.3 and sigma g = 1.0). This surprisingly small effect of the DOP heterodispersion on HEPA-filter penetration is due to the response function of the owl that is similar to the response of the photometer. Changes in the particle-size distribution are therefore seen in a similar fashion by both the photometer and the owl. We also show that replacing the owl with modern particle-size spectrometers may lead to large errors in filter penetration because the particle-size spectrometers do not provide measurements that correspond to the photometer measurements. 15 references, 16 figures.

  20. Probabilistic predictions of penetrating injury to anatomic structures.

    PubMed Central

    Ogunyemi, O.; Webber, B.; Clarke, J. R.

    1997-01-01

    This paper presents an interactive 3D graphical system which allows the user to visualize different bullet path hypotheses and stab wound paths and computes the probability that an anatomical structure associated with a given penetration path is injured. Probabilities can help to identify those anatomical structures which have potentially critical damage from penetrating trauma and differentiate these from structures that are not seriously injured. Images Figure 3 Figure 4 PMID:9357718