WorldWideScience

Sample records for effects host penetration

  1. Active penetration of Trypanosoma cruzi into host cells: historical considerations and current concepts

    Directory of Open Access Journals (Sweden)

    Tecia Maria Ulisses Carvalho

    2013-01-01

    Full Text Available A significant number of scientific groups working on several countries have made efforts to better understand the process of invasion of several types of host cells by Trypanosoma cruzi, the etiologic agent of Chagas disease. In this mini-review we analyze the two mechanisms of invasion considered to be relevant: active penetration and endocytosis. The term active penetration is considered in view of its original description by Dvorak and co-workers. Taking into consideration all results obtained we conclude that endocytosis, with its many variations, is the only mechanism used by T. cruzi to invade host cells.

  2. Penetration effect in uniaxial anisotropic metamaterials

    Science.gov (United States)

    Vytovtov, K.; Barabanova, E.; Zouhdi, S.

    2018-02-01

    Plane harmonic wave propagation along an interface between vacuum and a semi-infinite anisotropic metamaterial is considered. Possibility of penetration effect in the considered case is studied. It is shown that there is a bulk wave within the anisotropic metamaterial with an arbitrary orientation of the anisotropy axis. It is also proved that a reflected wave must propagate perpendicularly to the interface in the case of the extraordinary wave. Moreover, no wave is reflected in the case of ordinary wave propagation.

  3. Vehicle effects on human stratum corneum absorption and skin penetration.

    Science.gov (United States)

    Zhang, Alissa; Jung, Eui-Chang; Zhu, Hanjiang; Zou, Ying; Hui, Xiaoying; Maibach, Howard

    2017-05-01

    This study evaluated the effects of three vehicles-ethanol (EtOH), isopropyl alcohol (IPA), and isopropyl myristate (IPM)-on stratum corneum (SC) absorption and diffusion of the [(14)C]-model compounds benzoic acid and butenafine hydrochloride to better understand the transport pathways of chemicals passing through and resident in SC. Following application of topical formulations to human dermatomed skin for 30 min, penetration flux was observed for 24 h post dosing, using an in vitro flow-through skin diffusion system. Skin absorption and penetration was compared to the chemical-SC (intact, delipidized, or SC lipid film) binding levels. A significant vehicle effect was observed for chemical skin penetration and SC absorption. IPA resulted in the greatest levels of intact SC/SC lipid absorption, skin penetration, and total skin absorption/penetration of benzoic acid, followed by IPM and EtOH, respectively. For intact SC absorption and total skin absorption/penetration of butenafine, the vehicle that demonstrated the highest level of sorption/penetration was EtOH, followed by IPA and IPM, respectively. The percent doses of butenafine that were absorbed in SC lipid film and penetrated through skin in 24 h were greatest for IPA, followed by EtOH and IPM, respectively. The vehicle effect was consistent between intact SC absorption and total chemical skin absorption and penetration, as well as SC lipid absorption and chemical penetration through skin, suggesting intercellular transport as a main pathway of skin penetration for model chemicals. These results suggest the potential to predict vehicle effects on skin permeability with simple SC absorption assays. As decontamination was applied 30 min after chemical exposure, significant vehicle effects on chemical SC partitioning and percutaneous penetration also suggest that skin decontamination efficiency is vehicle dependent, and an effective decontamination method should act on chemical solutes in the lipid domain.

  4. Effect of Liquid Penetrant Sensitivity on Probability of Detection

    Science.gov (United States)

    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.

  5. Penetration Enhancement Effect of Turpentine Oil on Transdermal ...

    African Journals Online (AJOL)

    Purpose: To prepare transdermal films of ketorolac tromethamine (KT) and study the effect of turpentine oil as a penetration enhancer for the drug. Methods: Transdermal films of KT were prepared with Carbopol-934 and ethyl cellulose, with turpentine oil as the penetration enhancer, using solvent evaporation method.

  6. Myosins XI modulate host cellular responses and penetration resistance to fungal pathogens

    Science.gov (United States)

    Yang, Long; Qin, Li; Liu, Guosheng; Peremyslov, Valera V.; Dolja, Valerian V.; Wei, Yangdou

    2014-01-01

    The rapid reorganization and polarization of actin filaments (AFs) toward the pathogen penetration site is one of the earliest cellular responses, yet the regulatory mechanism of AF dynamics is poorly understood. Using live-cell imaging in Arabidopsis, we show that polarization coupled with AF bundling involves precise spatiotemporal control at the site of attempted penetration by the nonadapted barley powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh). We further show that the Bgh-triggered AF mobility and organelle aggregation are predominately driven by the myosin motor proteins. Inactivation of myosins by pharmacological inhibitors prevents bulk aggregation of organelles and blocks recruitment of lignin-like compounds to the penetration site and deposition of callose and defensive protein, PENETRATION 1 (PEN1) into the apoplastic papillae, resulting in attenuation of penetration resistance. Using gene knockout analysis, we demonstrate that highly expressed myosins XI, especially myosin XI-K, are the primary contributors to cell wall-mediated penetration resistance. Moreover, the quadruple myosin knockout mutant xi-1 xi-2 xi-i xi-k displays impaired trafficking pathway responsible for the accumulation of PEN1 at the cell periphery. Strikingly, this mutant shows not only increased penetration rate but also enhanced overall disease susceptibility to both adapted and nonadapted fungal pathogens. Our findings establish myosins XI as key regulators of plant antifungal immunity. PMID:25201952

  7. Attachment, penetration and early host defense mechanisms during the infection of filamentous brown algae by Eurychasma dicksonii.

    Science.gov (United States)

    Tsirigoti, Amerssa; Beakes, Gordon W; Hervé, Cécile; Gachon, Claire M M; Katsaros, Christos

    2015-05-01

    Eurychasma dicksonii is one of the most common and widespread marine pathogens and attacks a broad spectrum of more than 45 brown algal species. The present study focuses on the mechanism used by the pathogen to attach on the host cell wall and force its way into algal cells. Ultrastructural examination revealed a needle-like structure which develops within the attached spore and extends along its main axis. Particular cell wall modifications are present at the basal part of the spore (adhesorium pad) and guide the needle-like tool to penetrate perpendicularly the host cell wall. The unique injection mechanism is shared with Haptoglossa species which suggests that this is an important characteristic of early diverging oomycetes. Furthermore, the encystment and adhesion mechanism of E. dicksonii shows significant similarities with other oomycetes, some of which are plant pathogens. Staining and immunolabelling techniques showed the deposition of β-1,3-glucans on the host cell wall at the pathogen penetration site, a strategy similar to physical responses previously described only in infected plant cells. It is assumed that the host defense in terms of callose-like deposition is an ancient response to infection.

  8. Monitoring the appositions of posterior graft-host junctions with anterior segment optical coherence tomogram after penetrating keratoplasty.

    Science.gov (United States)

    Raj, Anuradha; Dhasmana, Renu; Bahadur, Harsh; Nagpal, R C

    2017-04-01

    This study aimed to monitor the graft-host junction's (GHJ's) apposition with anterior segment optical coherence tomogram after penetrating keratoplasty (PK) and correlate the analysis with the preoperative diagnosis. Fifty-one eyes of 50 patients with various preoperative diagnosis of adherent leucoma, pseudophakic bullous keratopathy, corneal opacity or scarring, graft failure, corneal dystrophy and anterior staphyloma, who underwent PK for optical purposes were reviewed retrospectively. Based on the age, the patients were divided into groups 1 and II: those aged ≤40 and >40 years, respectively. Anterior segment optical coherence tomography was done for all these eyes to evaluate the posterior graft-host junction. All graft-host junction patterns were classified as well apposed, and malapposed with various components like hill, gap, step and tag. The comparisons of various clinical parameters were done for the various malapposed junction groups (hill, gap, step and tag). A total of 408 graft-host junction cross sections of 51 eyes were analysed. Amongst them 70 (17.15 %) sections were well apposed, and 338 (82.84 %) were malapposed. Most frequent type of malapposition was hill: 164 sections (40.19 %) followed by step: 139 sections (34.06 %). The distribution of graft-host junction alignment patterns varied amongst all the indications. Patients with preoperative diagnosis of adherent leucoma and corneal dystrophy had predominantly steps pattern in 65 (40.62 %) and 12 (75 %) sections, respectively. Hill pattern was seen predominantly in PBK, corneal opacity, graft failure and anterior staphyloma in 55 (42.96 %), 16 (40 %), 22 (45.83 %) and 8 (50 %) sections, respectively. Comparisons of various clinical characteristics like intraocular pressure, central corneal thickness, best-corrected visual acuity, astigmatism and size of graft with the various malapposed patterns showed significant differences in best-corrected visual acuity and keratometric

  9. Effects of soap-water wash on human epidermal penetration.

    Science.gov (United States)

    Zhu, Hanjiang; Jung, Eui-Chang; Phuong, Christina; Hui, Xiaoying; Maibach, Howard

    2016-08-01

    Skin decontamination is a primary interventional method used to decrease dermal absorption of hazardous contaminants, including chemical warfare agents, pesticides and industrial pollutants. Soap and water wash, the most common and readily available decontamination system, may enhance percutaneous absorption through the "wash-in effect." To understand better the effect of soap-water wash on percutaneous penetration, and provide insight to improving skin decontamination methods, in vitro human epidermal penetration rates of four C(14) -labeled model chemicals (hydroquinone, clonidine, benzoic acid and paraoxon) were assayed using flow-through diffusion cells. Stratum corneum (SC) absorption rates of these chemicals at various hydration levels (0-295% of the dry SC weights) were determined and compared with the results of the epidermal penetration study to clarify the effect of SC hydration on skin permeability. Results showed accelerated penetration curves of benzoic acid and paraoxon after surface wash at 30 min postdosing. Thirty minutes after washing (60 min postdosing), penetration rates of hydroquinone and benzoic acid decreased due to reduced amounts of chemical on the skin surface and in the SC. At the end of the experiment (90 min postdosing), a soap-water wash resulted in lower hydroquinone penetration, greater paraoxon penetration and similar levels of benzoic acid and clonidine penetration compared to penetration levels in the non-wash groups. The observed wash-in effect agrees with the enhancement effect of SC hydration on the SC chemical absorption rate. These results suggest SC hydration derived from surface wash to be one cause of the wash-in effect. Further, the occurrence of a wash-in effect is dependent on chemical identity and elapsed time between exposure and onset of decontamination. By reducing chemical residue quantity on skin surface and in the SC reservoir, the soap-water wash may decrease the total quantity of chemical absorbed in the

  10. Cutaneous Penetration-Enhancing Effect of Menthol: Calcium Involvement.

    Science.gov (United States)

    Joshi, Amit; Joshi, Abhay; Patel, Hiren; Ponnoth, Dovenia; Stagni, Grazia

    2017-07-01

    Menthol is a naturally occurring terpene used as a penetration enhancer in topical and transdermal formulations. Literature shows a growing interest in menthol's interactions with the transient receptor potential melastatin 8. A decrease in extracellular Ca 2+ due to the activation of the transient receptor potential melastatin 8 receptor produces inhibition of E-cadherin expression that is responsible for cell-cell adhesion. Because calcium is present in the entire epidermis, the purpose of this study is to evaluate whether the aforementioned properties of menthol are also related to its penetration-enhancing effects. We formulated 16 gels: (i) drug-alone (diphenhydramine or lidocaine), (ii) drug with menthol, (iii) drug, menthol, and calcium channel blocker (CCB; verapamil or diltiazem), and (iv) drug and CCB. In vitro studies showed no effect of the CCB on the release of the drugs either with or without menthol. In vivo experiments were performed for each drug/menthol/CCB combination gel by applying 4 formulations on a shaved rabbit's dorsum on the same day. Dermis concentration profiles were assessed with microdialysis. The gels containing menthol showed higher penetration of drugs than those without whereas the addition of the CCB consistently inhibited the penetration-enhancing effects of menthol. In summary, these findings strongly support the involvement of calcium in the penetration-enhancing effect of menthol. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  11. Biological effect of penetration controlled irradiation with ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Atsushi; Shimizu, Takashi; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Watanabe, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Yamashita, Takao

    1997-03-01

    To investigate the effect of local irradiation with ion beams on biological systems, technique for penetration controlled irradiation has been established. The range in a target was controlled by changing the distance from beam window in the atmosphere, and could be controlled linearly up to about 31 {mu}m in biological material. In addition, the effects of the penetration controlled irradiations with 1.5 MeV/u C and He ions were examined using tobacco pollen. The increased frequency of leaky pollen produced by ion beams suggests that the efficient pollen envelope damages would be induced at the range-end of ion beams. (author)

  12. Cell penetrating peptides to dissect host-pathogen protein-protein interactions in Theileria -transformed leukocytes

    KAUST Repository

    Haidar, Malak

    2017-09-08

    One powerful application of cell penetrating peptides is the delivery into cells of molecules that function as specific competitors or inhibitors of protein-protein interactions. Ablating defined protein-protein interactions is a refined way to explore their contribution to a particular cellular phenotype in a given disease context. Cell-penetrating peptides can be synthetically constrained through various chemical modifications that stabilize a given structural fold with the potential to improve competitive binding to specific targets. Theileria-transformed leukocytes display high PKA activity, but PKAis an enzyme that plays key roles in multiple cellular processes; consequently genetic ablation of kinase activity gives rise to a myriad of confounding phenotypes. By contrast, ablation of a specific kinase-substrate interaction has the potential to give more refined information and we illustrate this here by describing how surgically ablating PKA interactions with BAD gives precise information on the type of glycolysis performed by Theileria-transformed leukocytes. In addition, we provide two other examples of how ablating specific protein-protein interactions in Theileria-infected leukocytes leads to precise phenotypes and argue that constrained penetrating peptides have great therapeutic potential to combat infectious diseases in general.

  13. Clinical effect of femtosecond laser assisted penetrating corneal transplantation operation

    Directory of Open Access Journals (Sweden)

    Hong-Jian Zhou

    2014-10-01

    Full Text Available AIM: To observe the clinical effect of femtosecond laser assisted penetrating keratoplasty. METHODS: Twenty-four cases(24 eyeswith corneal lesions were performed with femtosecond laser assisted penetrating keratoplasty. Preoperative and postoperative endothelial cell density and visual quality were compared.RESULTS: One week after operation, corneal grafts were clear in 21 eyes(87.5%, mild cloudy in 3 eyes(12.5%; visual acuity ≥0.5 in 18 eyes(75.0%, 0.2~0.4 in 6 eyes(25.0%. After 3mo the mean corneal astigmatism was 2.16±0.21D(range 2.25~3.09D. Compared to conventional penetrating keratoplasty which mean corneal astigmatism was average 3.67±0.38D after operation, there was significant difference between two groups(PPCONCLUSION: Femtosecond laser assisted penetrating corneal transplantation operation can improve patient's visual quality. And compared to traditional penetrating keratoplasty astigmatism decreased significantly, incision can be made in individual shape more precisely and neatly.

  14. Effects of exogenous oxytocin on cervical penetration of Iranian ewes

    African Journals Online (AJOL)

    ... has no significant effect on induced cervix penetration by OT. Therefore, this dose is the applicable dose for the cervix dilation and transcervical artificial insemination and embryo recovery in Iranian ewes. Key words: Iranian ewes, oxytocin, cervical dilation, transcervical artificial insemination, transcervical embryo transfer.

  15. Correlation between the graft–host junction of penetrating keratoplasty by anterior segment-optical coherence tomography and the magnitude of postoperative astigmatism

    Directory of Open Access Journals (Sweden)

    Ghada Azab Nassar

    2017-01-01

    Full Text Available Purpose: This study aimed to evaluate the alignment pattern of the graft–host junction after penetrating keratoplasty (PK by anterior segment-optical coherence tomography (AS-OCT and to correlate this pattern with the magnitude of postoperative astigmatism. Methods: This retrospective observational study was carried out on forty patients who underwent PK from February 2013 to August 2014. AS-OCT was performed, and the graft–host junctions were classified into well-apposed junction, malapposed junction, and equally apposed junction. Mal-apposition is subdivided into gap and protrusion. The correlations between clinical characteristics, wound profiles from the AS-OCT, and the magnitude of postoperative astigmatism by Sirius camera (Costruzione Strumenti Oftalmici [CSO], Florence, Italy (CSO, Sirius, were analyzed. Results: Graft–host junctions from forty patients were analyzed; 18 eyes had well-apposed junctions, ten eyes had malapposed junctions, and 12 had equally apposed junctions. The mean cylinder was −9.44 ± −4.00D in well-apposed group, −13.40 ± −5.01D in malapposed group, and −4.67 ± −0.94D in equally apposed group. Alignment pattern of the graft–host junction correlated significantly with the magnitude of astigmatism (P = 0.034. Preoperative corneal diseases did not have an effect on the magnitude of astigmatism (P = 0.123. Conclusion: The alignment pattern of the graft–host junction by AS-OCT can explain the postoperative astigmatism after PK where it correlates significantly with the magnitude of astigmatism.

  16. Penetration and Effectiveness of Micronized Copper in Refractory Wood Species.

    Directory of Open Access Journals (Sweden)

    Chiara Civardi

    Full Text Available The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP, which is being impregnated with micronized copper (MC wood preservatives since 2006. These formulations are composed of copper (Cu carbonate particles (CuCO3·Cu(OH2, with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH2 particles that successively release Cu2+ ions (reservoir effect. The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect.

  17. Effect of collagen shields on corneal epithelialization following penetrating keratoplasty.

    Science.gov (United States)

    Ruffini, J J; Aquavella, J V; LoCascio, J A

    1989-01-01

    To evaluate the effects of collagen shields on corneal epithelial healing following keratoplasty, we conducted a prospective study of 89 consecutive penetrating keratoplasty patients over a 9-month period, applying collagen shields in alternate cases. Eyes were evaluated on the first and on the eighth postoperative day. The appearance of the epithelium was graded on a scale from 0 to 4. Independent variables, such as donor age, patient age, patient and donor sex, death to preservation time, and donor time in K-Sol media prior to surgery, were also evaluated. Donor corneas treated with collagen demonstrated less epithelial staining and smaller epithelial defects on the first day following surgery. The results were evaluated with a Student's t test and were found to be significant (P less than 0.001). We conclude that the application of porcine collagen shields following keratoplasty is an effective means of encouraging reepithelialization of the graft.

  18. Calculation of the Effect of Random Superfluid Density on the Temperature Dependence of the Penetration Depth

    Energy Technology Data Exchange (ETDEWEB)

    Lippman, Thomas; Moler, Kathryn A.

    2012-07-20

    Microscopic variations in composition or structure can lead to nanoscale inhomogeneity in superconducting properties such as the magnetic penetration depth, but measurements of these properties are usually made on longer length scales. We solve a generalized London equation with a non-uniform penetration depth {lambda}(r), obtaining an approximate solution for the disorder-averaged Meissner screening. We find that the effective penetration depth is different from the average penetration depth and is sensitive to the details of the disorder. These results indicate the need for caution when interpreting measurements of the penetration depth and its temperature dependence in systems which may be inhomogeneous.

  19. Effect of Corneal Thickness on the Penetration of Topical Vancomycin.

    Science.gov (United States)

    Spierer, Oriel; Regenbogen, Michael; Lazar, Moshe; Yatziv, Yossi

    2015-10-01

    To study the influence of corneal thickness on intraocular penetration of topical ophthalmic drops, using vancomycin 50 mg/mL drops as a model. The study included 58 eyes of 58 patients undergoing phacoemulsification cataract extraction. The central corneal thickness was measured by ultrasonic pachymetry on the day of surgery. Thirty minutes before the surgery, one drop of topical vancomycin 50 mg/mL was instilled three times with 10-minute intervals: 30 minutes, 20 minutes, and 10 minutes before the surgery. At the beginning of surgery, a small specimen of aqueous humor was aspirated and sent to the laboratory for measurement of drug concentration to determine the effect of corneal thickness on vancomycin concentration in the anterior chamber. There was insufficient amount of aqueous humor for analysis in 9 samples, leaving a total of 49 samples. The mean central corneal thickness was 539.7 (±39.5) μm (range, 458 to 635 μm). The mean vancomycin concentration in the anterior chamber was 0.220 (±0.209) μg/mL. There was no significant association between vancomycin concentration and corneal thickness (r = -0.07, p = 0.62, Pearson correlation). When patients were divided into three groups based on the mean (±1 SD) central corneal thickness, no significant differences in vancomycin concentrations (in micrograms per milliliter) were encountered: 0.267 (±0.247) (for corneal thickness thickness of 500.2 to 579.2 μm), and 0.200 (±0.160) (for corneal thickness >579.2 μm) (p = 0.73, analysis of variance). Corneal thickness does not influence the penetration of topically applied vancomycin into the anterior chamber.

  20. Effect of Drainage Conditions on Cone Penetration Testing in Silty Soils

    DEFF Research Database (Denmark)

    Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2011-01-01

    This paper discusses the challenges that occur when performing Cone Penetration Tests (CPT) in silty soil due to changes in drainage conditions. In this paper, CPT results from various papers and researchers are collected and interpreted. Results from cone penetrations tests with various...... penetration rates is analysed, and it is shown how the changes in drainage condition, caused by the change in penetration rate, affects the plot in the soil classification charts. In addition, the effect on changes in penetration rate is compared for clay and silt, respectively, where the silty soil is more...... susceptible towards change in penetration rate. A normalized penetration rate is implemented in order to compare various cone resistance results, and hence investigate the changes from undrained to partially drained and from partially drained to fully drained....

  1. Simple Amides of Oleanolic Acid as Effective Penetration Enhancers

    Science.gov (United States)

    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

  2. The Effect of Bacteria Penetration on Chalk Permeability

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Shapiro, Alexander; Nielsen, Sidsel Marie

    Bacteria selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery. Bacteria can plug the water-bearing zones of a reservoir, thus altering the flow paths and improving sweep efficiency. It is known that the bacteria can penetrate deeply...... into reservoirs, however, a complete understanding of the penetration behavior of bacteria is lacking, especially in chalk formations where the pore throat sizes are almost comparable with the sizes of bacteria vegetative cells. This study investigates the penetration of bacteria into chalk. Two bacteria types......, the spore forming Bacillus licheniformis 421 and the non-spore forming Pseudomonas putida K12, were used. The core plugs were Stevns Klint outcrop with initial permeability at 2-4 mD. The results revealed that bacteria were able to penetrate and to be transported through the chalk. Furthermore, a higher...

  3. The Lightning Electromagnetic Pulse Coupling Effect Inside the Shielding Enclosure With Penetrating Wire

    Science.gov (United States)

    Jiao, Xue; Yang, Bo

    2017-10-01

    To study the lightning electromagnetic pulse (LEMP) coupling and protection problems of shielding enclosure with penetrating wire, we adopt the model with proper size which is close to the practical engineering and the two-step finite-difference time-domain (FDTD) method is used for calculation in this paper. It is shown that the coupling voltage on the circuit lead inside the enclosure increases about 34 dB, when add 1.0 m long penetrating wire at the aperture, comparing with the case without penetrating wire. Meanwhile, the waveform, has the same wave outline as the lightning current source, shows that the penetrating wire brings a large number of low frequency component into the enclosure. The coupling effect in the enclosure will reduce greatly when penetrating wire has electrical connection with the enclosure at the aperture and the coupling voltage increase only about 12 dB than the case without penetrating wire. Moreover, the results show that though the waveguide pipe can reduce the coupling effect brought by the penetrating wire, the exposing part of penetrating wire can increase the coupling when the penetrating wire outside the enclosure is longer than the waveguide pipe and the longer the exposing part is, the stronger the coupling is.

  4. Effect of Different Agitation Techniques on the Penetration of Irrigant and Sealer into Dentinal Tubules.

    Science.gov (United States)

    Gu, Yu; Perinpanayagam, Hiran; Kum, David J W; Yoo, Yeon-Jee; Jeong, Jin-Sun; Lim, Sang-Min; Chang, Seok-Woo; Baek, Seung-Ho; Zhu, Qiang; Kum, Kee-Yeon

    2017-02-01

    The aim of this study was to compare the effectiveness of five intracanal agitation techniques on the penetration of irrigant and sealer into dentinal tubules. Intracanal agitation techniques could promote chemomechanical debridement and the sealing of root canals during endodontic treatment. However, there is limited evidence for the agitation effect of Nd:YAP laser. Human maxillary premolars with single straight canals (N = 60) were prepared with ProTaper Next(®) NiTi rotary files (Dentsply Maillefer) up to X4 (ISO 40 size). Rhodamine B-labeled sodium hypochlorite was used for final irrigation together with the conventional syringe (control), sonic, ultrasonic, Nd:YAP laser, or V-Clean™ endodontic agitation system. All canals were obturated with gutta-percha and fluorescein isothiocyanate-labeled AH Plus sealer. Transverse sections were obtained at 2, 5, and 8 mm from the apex and observed under confocal laser scanning microscopy. Maximum penetration depth and penetration percentage of both irrigant and sealer were recorded. Kruskal-Wallis and Mann-Whitney tests were performed for multiple comparisons. The Spearman coefficient was calculated to confirm correlations between irrigant and sealer penetration. Laser agitation attained the most irrigant and sealer penetration depth and penetration percentage (p penetration percentage than the control group at 2 mm from the apex (p penetration correlated significantly for all agitation techniques (p penetration of irrigant and sealer at one or more sectioned levels from the apex.

  5. A Genetic Screen for Pathogenicity Genes in the Hemibiotrophic Fungus Colletotrichum higginsianum Identifies the Plasma Membrane Proton Pump Pma2 Required for Host Penetration.

    Science.gov (United States)

    Korn, Martin; Schmidpeter, Johannes; Dahl, Marlis; Müller, Susanne; Voll, Lars M; Koch, Christian

    2015-01-01

    We used insertional mutagenesis by Agrobacterium tumefaciens mediated transformation (ATMT) to isolate pathogenicity mutants of Colletotrichum higginsianum. From a collection of 7200 insertion mutants we isolated 75 mutants with reduced symptoms. 19 of these were affected in host penetration, while 17 were affected in later stages of infection, like switching to necrotrophic growth. For 16 mutants the location of T-DNA insertions could be identified by PCR. A potential plasma membrane H(+)-ATPase Pma2 was targeted in five independent insertion mutants. We genetically inactivated the Ku80 component of the non-homologous end-joining pathway in C. higginsianum to establish an efficient gene knockout protocol. Chpma2 deletion mutants generated by homologous recombination in the ΔChku80 background form fully melanized appressoria but entirely fail to penetrate the host tissue and are non-pathogenic. The ChPMA2 gene is induced upon appressoria formation and infection of A. thaliana. Pma2 activity is not important for vegetative growth of saprophytically growing mycelium, since the mutant shows no growth penalty under these conditions. Colletotrichum higginsianum codes for a closely related gene (ChPMA1), which is highly expressed under most growth conditions. ChPMA1 is more similar to the homologous yeast genes for plasma membrane pumps. We propose that expression of a specific proton pump early during infection may be common to many appressoria forming fungal pathogens as we found ChPMA2 orthologs in several plant pathogenic fungi.

  6. Dermal in vitro penetration of methiocarb, paclobutrazol, and pirimicarb: effect of nonylphenolethoxylate and protective gloves.

    Science.gov (United States)

    Nielsen, J B; Andersen, H R

    2001-02-01

    Dermal exposure has become the major route of human occupational exposure to pesticides. Detergents are used as part of formulated pesticide products and are known to change the barrier properties of human skin in vitro. However, studies on the influence of detergents as well as protective glove materials on dermal penetration of pesticides are scarce. In an experiment using in vitro static diffusion cells mounted with human skin, we evaluated the effect of nonylphenol-ethoxylate on dermal penetration of three extensively used pesticides--methiocarb, paclobutrazol, and pirimicarb--and the protection against dermal penetration offered by protective gloves made of latex or nitrile. There was a general tendency, though not statistically significant for all pesticides, for nonylphenolethoxylate to decrease the percutaneous penetration of the three pesticides. The nitrile generally offered better protection against percutaneous penetration of pesticides than did latex, but the degree of protection decreased over time and depended on the pesticides used.

  7. GHG effects of spinning reserve for high penetration renewables

    Energy Technology Data Exchange (ETDEWEB)

    Louis Wibberley; Peter Scaife; Joe Winsen

    2008-03-15

    This study gives a high level assessment of the greenhouse gas cost implications of providing additional backup for intermittent renewable power at a high level (20%) of penetration. The report considers international experience with higher levels of renewable generation, the Australian electricity system, and the current and likely future levels of renewables on the grids. To enable coal to provide back up/spinning reserve with a high degree of flexibility it is proposed that direct injected coal engines and novel gasification/gas engine combinations be considered. 31 refs., 17 figs., 6 tabs.

  8. Dermal In Vitro Penetration of Methiocarb, Paclobutrazol, and Pirimicarb: Effect of Nonylphenolethoxylate and Protective Gloves

    National Research Council Canada - National Science Library

    Jesper Bo Nielsen; Helle Raun Andersen

    2001-01-01

    .... In an experiment using in vitro static diffusion cells mounted with human skin, we evaluated the effect of nonylphenolethoxylate on dermal penetration of three extensively used pesticides-methiocarb...

  9. [Filtering facepieces: effect of oily aerosol load on penetration through the filtering material].

    Science.gov (United States)

    Plebani, Carmela; Listrani, S; Di Luigi, M

    2010-01-01

    Electrostatic filters are widely used in applications requiring high filtration efficiency and low pressure drop. However various studies showed that the penetration through electrostatic filters increases during exposure to an aerosol flow. This study investigates the effects of prolonged exposure to an oily aerosol on the penetration through filtering facepieces available on the market. Some samples of FFP1, FFP2 and FFP3 filtering facepieces were exposed for 8 hours consecutively to a paraffin oil polydisperse aerosol. At the end of the exposure about 830 mg of paraffin oil were deposited in the facepiece. All the examined facepieces showed penetration values that increased with paraffin oil load while pressure drop values were substantially the same before and after exposure. The measured maximum penetration values did not exceed the maximum penetration values allowed by the European technical standards, except in one case. According to the literature, 830 mg of oil load in a facepiece is not feasible in workplaces over an eight- hour shift. However, the trend of the penetration versus exposure mass suggests that if the load increases, the penetration may exceed the maximum allowed values. For comparison a mechanical filter was also studied. This showed an initial pressure drop higher than FFP2 filtering facepieces characterized by comparable penetration values. During exposure the pressure drop virtually doubled while penetration did not change. The increase in penetration with no increase in pressure drop in the analyzed facepieces indicates that it is necessary to comply with the information supplied by the manufacturer that restricts their use to a single shift.

  10. A cyclohexanecarboxamide derivative with inhibitory effects on Schistosoma mansoni cercarial serine protease and penetration of mice skin by the parasite.

    Science.gov (United States)

    Bahgat, Mahmoud; Aboul-Enein, Mohamed N; El Azzouny, Aida A; Maghraby, Amany; Ruppel, Andreas; Soliman, Wael M

    2009-01-01

    A cyclohexanecarboxamide derivative, N-phenyl-N-[1-(piperidine-1-carbonyl)cyclohexyl] benzamide (MNRC-5), was evaluated for its inhibitory effects on Schistosoma mansoni cercarial serine protease activity and cercarial penetration. MNRC-5 exerted an inhibitory effect on S. mansoni cercarial serine protease at serial concentrations of the specific chromogenic substrate Boc-Val-Leu-Gly-Arg-PNA for such enzyme family and the inhibitory coefficient (Ki) value was deduced. Moreover, topical treatment of mice tails with the most potent inhibitory concentration of MNRC-5 formulated in jojoba oil successfully blocked cercarial penetration as demonstrated by a significant reduction (75%; p jojoba oil base containing no MNRC-5. In addition, the IgM and IgG reactivities to crude S. mansoni cercarial, worm and egg antigens were generally lower in sera from treated infected mice than untreated infected mice. In conclusion, we report on a new serine protease inhibitor capable for blocking penetration of host skin by S. mansoni cercariae as measured by lowering worm burden and decrease in the levels of both IgM and IgG towards different bilharzial antigens upon topical treatment.

  11. Quantum shielding effects on the Gamow penetration factor for nuclear fusion reaction in quantum plasmas

    Science.gov (United States)

    Lee, Myoung-Jae; Jung, Young-Dae

    2017-01-01

    The quantum shielding effects on the nuclear fusion reaction process are investigated in quantum plasmas. The closed expression of the classical turning point for the Gamow penetration factor in quantum plasmas is obtained by the Lambert W-function. The closed expressions of the Gamow penetration factor and the cross section for the nuclear fusion reaction in quantum plasmas are obtained as functions of the plasmon energy and the relative kinetic energy by using the effective interaction potential with the WKB analysis. It is shown that the influence of quantum screening suppresses the Sommerfeld reaction factor. It is also shown that the Gamow penetration factor increases with an increase of the plasmon energy. It is also shown that the quantum shielding effect enhances the deuterium formation by the proton-proton reaction in quantum plasmas. In addition, it is found that the energy dependences on the reaction cross section and the Gamow penetration factor are more significant in high plasmon-energy domains.

  12. A Molecular Interpretation on the Different Penetration Enhancement Effect of Borneol and Menthol towards 5-Fluorouracil

    Directory of Open Access Journals (Sweden)

    Ran Wang

    2017-12-01

    Full Text Available Borneol and menthol are terpenes that are widely used as penetration enhancers in transdermal drug delivery. To explore their penetration-enhancement effects on hydrophilic drugs, 5-fluorouracil (5-FU was selected as a model drug. An approach that combined in vitro permeation studies and coarse-grained molecular dynamics was used to investigate their penetration-enhancement effect on 5-FU. The results showed that although both borneol and menthol imparted penetration-enhancement effects on 5-FU, these differed in terms of their mechanism, which may account for the observed variations in penetration-enhancement effects. The main mechanism of action of menthol involves the disruption of the stratum corneum (SC bilayer, whereas borneol involves multiple mechanisms, including the disruption of the SC bilayer, increasing the diffusion coefficient of 5-FU, and inducing the formation of transient pores. The findings of the present study improve our understanding of the molecular mechanism that is underlying 5-FU penetration-enhancement by borneol and menthol, which may be utilized in future investigations and applications.

  13. The Effect of Different Suturing Techniques on Astigmatism after Penetrating Keratoplasty

    OpenAIRE

    Kim, Sang Jin; Wee, Won Ryang; Lee, Jin Hak; Kim, Mee Kum

    2008-01-01

    The purpose of this study was to compare the effects on astigmatism after penetrating keratoplasty with three different suture techniques. In this prospective study, 38 eyes of 38 patients underwent penetrating keratoplasty with three suturing techniques: interrupted, single running, and double running. Topographic astigmatism was measured at 2, 6, 12, and 18 months after keratoplasty. During 18 months after surgery, the interrupted suture group had higher astigmatism than the double running ...

  14. Thermal-Hydraulic Integral Effect Test with the ATLS for Investigation on CEDM Penetration Nozzle Integrity

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyoungho; Seokcho; Park, Hyunsik; Choi, Namhyun; Park, Yusun; Kim, Jongrok; Bae, Byounguhn; Kim, Yeonsik; Choi, Kiyong; Song, Chulhwa [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    In this study, thermal-hydraulic integral effect test with the ATLAS (Advanced Thermal-Hydraulic Test Loop for Accident Simulation) was performed for simulating a failure of CEDM penetration nozzle. The main objectives of the present test were not only to provide physical insight into the system response during a failure of CEDM penetration nozzle but also to establish an integral effect test database for the validation of the safety analysis codes. Furthermore, present experimental data were utilized to resolve the safety issue raised by the PWSCC at the CEDM penetration nozzle of the YGN-3. Thermal-hydraulic integral effect test with the ATLAS was performed for simulating a failure of CEDM penetration nozzle. Failure of two penetration nozzles of the CEDM in the APR1400 was simulated. Initial and boundary conditions were determined with respect to the reference conditions of the APR1400. However, with an aim of corresponding to the YGN-3 situation, the safety injection water was supplied via CLI mode. Compared to the cold leg break SBLOCA, the consequences of the event were milder in terms of a loop seal clearance, break flow rate, collapsed water level, and PCT. This could be mainly attributed to the small break flow rate in case of the failure in the RPV upper head. Present experimental data were utilized to resolve the safety issue raised by the PWSCC at the CEDM penetration nozzle of the YGN-3.

  15. The Effect and Mechanism of Transdermal Penetration Enhancement of Fu's Cupping Therapy: New Physical Penetration Technology for Transdermal Administration with Traditional Chinese Medicine (TCM) Characteristics.

    Science.gov (United States)

    Xie, Wei-Jie; Zhang, Yong-Ping; Xu, Jian; Sun, Xiao-Bo; Yang, Fang-Fang

    2017-03-27

    In this paper, a new type of physical penetration technology for transdermal administration with traditional Chinese medicine (TCM) characteristics is presented. Fu's cupping therapy (FCT), was established and studied using in vitro and in vivo experiments and the penetration effect and mechanism of FCT physical penetration technology was preliminarily discussed. With 1-(4-chlorobenzoyl)-5-methoxy-2-methylindole-3-ylacetic acid (indomethacin, IM) as a model drug, the establishment of high, medium, and low references was completed for the chemical permeation system via in vitro transdermal tests. Furthermore, using chemical penetration enhancers (CPEs) and iontophoresis as references, the percutaneous penetration effect of FCT for IM patches was evaluated using seven species of in vitro diffusion kinetics models and in vitro drug distribution; the IM quantitative analysis method in vivo was established using ultra-performance liquid chromatography-tandem mass spectrometry technology (UPLC-MS/MS), and pharmacokinetic parameters: area under the zero and first moment curves from 0 to last time t (AUC0-t, AUMC0-t), area under the zero and first moment curves from 0 to infinity (AUC0-∞, AUMC0-∞), maximum plasma concentration (Cmax) and mean residence time (MRT), were used as indicators to evaluate the percutaneous penetration effect of FCT in vivo. Additionally, we used the 3(K) factorial design to study the joint synergistic penetration effect on FCT and chemical penetration enhancers. Through scanning electron microscopy (SEM) and transmission electron microscope (TEM) imaging, micro- and ultrastructural changes on the surface of the stratum corneum (SC) were observed to explore the FCT penetration mechanism. In vitro and in vivo skin permeation experiments revealed that both the total cumulative percutaneous amount and in vivo percutaneous absorption amount of IM using FCT were greater than the amount using CPEs and iontophoresis. Firstly, compared with the

  16. STUDIES ON ENERGY PENETRATION AND MARANGONI EFFECT DURING LASER MELTING PROCESS

    Directory of Open Access Journals (Sweden)

    K. ANTONY

    2015-04-01

    Full Text Available Many additive manufacturing processes use energy from laser beam to melt powder particles to form layered objects. This paper mainly focused its attention on some of the major factors which plays a vital role during laser melting, namely energy penetration, shrinkage, absorptivity and marangoni effect. A study was performed to simulate and validate the effect of energy density on Marangoni effect and energy penetration. Analytical solutions to moving heat source problems were developed and their effects on process parameters viz. energy penetration through a layer of powder particles were validated. The numerical investigations demonstrated the significant effect of energy density on laser beam towards the laser track. Finally, experiments were performed to validate the simulations using Nd: YAG laser on SS316L powder particles. Thus this study would enable in optimizing the process parameters of the additive manufacturing process.

  17. The effect of a speaking valve on laryngeal aspiration and penetration in children with tracheotomies.

    Science.gov (United States)

    Ongkasuwan, Julina; Turk, Catherine L; Rappazzo, Christina A; Lavergne, Katherine A; Smith, E O'Brian; Friedman, Ellen M

    2014-06-01

    Alterations in swallowing can occur after tracheotomy and can result in varying degrees of aspiration. In tracheotomized adult patients, use of a Passy Muir Speaking Valve (PMV) has been shown to decrease laryngeal penetration and aspiration of foods and liquids. The objective of this study was to determine if the PMV has a similar effect on laryngeal penetration and aspiration in tracheotomized children. This is a prospective case-control study. Pediatric patients with tracheotomies who were able to tolerate the PMV were identified. Modified barium swallow (MBS) was performed with and without the PMV. Two consistencies, thin liquids and purées, were used. Two speech language pathologists (SLPs), who were blinded to the PMV status, reviewed the recorded MBSs. Three swallows of each consistency were graded on an 8 point Penetration-Aspiration Scale. Residue in the vallecula, piriform sinuses, and posterior pharyngeal wall was graded. Twelve patients were included for analysis. Laryngeal penetration and aspiration was decreased with purées over liquids (P = 0.5 and P = 0.005, respectively) with either the sham valve or the PMV. The presence of the PMV decreased piriform sinus residue (P = 0.01); however, it did not demonstrate a decrease in laryngeal aspiration or penetration. Unlike in adults, the presence of PMV did not decrease laryngeal aspiration or penetration in children with tracheotomies. It did, however, improve piriform sinus residue. 3b. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  18. Numerical analysis on effective electric field penetration depth for interdigital impedance sensor

    Science.gov (United States)

    Kim, Chon-ung; Li, Guofeng; Li, Jie; Jong, Hakchol; Ro, Cholwu; Song, Yunho; Pak, Gilhung; Im, Songil

    2013-03-01

    Interdigital (finger-like) electrodes are widely used for electrical impedance and capacitance tomography of composite dielectric materials and complex insulating structures. Because of their advantages, they are now effectively introduced as capacitance sensors into a variety of industrial branches, agriculture, medical science, biological engineering, military branches, etc. In order to effectively apply the so-called interdigital impedance sensors in practice, of great importance is to optimize the sensor design parameters such as the electric field penetration depth, signal strength and so on. The general design principles of the interdigital capacitance sensor have been discussed for a long time by many researchers. However, there is no consensus on the definition of the effective electric field penetration depth of interdigital electrode. This paper discusses how to determine the effective electric field penetration depth of interdigital sensor on the basis of the refractive principle of electric field intensity and the FEM analyses of electric field distribution and capacitance for the sensor model.

  19. Adsorbate-metal bond effect on empirical determination of surface plasmon penetration depth.

    Science.gov (United States)

    Kegel, Laurel L; Menegazzo, Nicola; Booksh, Karl S

    2013-05-21

    The penetration depth of surface plasmons is commonly determined empirically from the observed response for adsorbate loading on gold surface plasmon resonance (SPR) substrates. However, changes in the SPR spectrum may originate from both changes in the effective refractive index near the metal surface and changes in the metal permittivity following covalent binding of the adsorbate layer. Herein, the significance of incorporating an additional adsorbate-metal bonding effect in the calculation is demonstrated in theory and in practice. The bonding effect is determined from the nonzero intercept of a SPR shift versus adsorbate thickness calibration and incorporated into the calculation of penetration depth at various excitation wavelengths. Determinations of plasmon penetration depth with and without the bonding response for alkanethiolate-gold are compared and are shown to be significantly different for a thiol monolayer adsorbate system. Additionally, plasmon penetration depth evaluated with bonding effect compensation shows greater consistency over different adsorbate thicknesses and better agreement with theory derived from Maxwell's equation, particularly for adsorbate thicknesses that are much smaller (<5%) than the plasmon penetration depth. The method is also extended to a more practically applicable polyelectrolyte multilayer adsorbate system.

  20. Effect of Penetrating Keratoplasty and Keratoprosthesis Implantation on the Posterior Segment of the Eye

    Science.gov (United States)

    Črnej, Alja; Omoto, Masahiro; Dohlman, Thomas H.; Gonzalez-Andrades, Miguel; Paschalis, Eleftherios I.; Cruzat, Andrea; Vu, T. H. Khanh; Doorenbos, Marianne; Chen, Dong Feng; Dohlman, Claes H.; Dana, Reza

    2016-01-01

    Purpose To compare the effects of post-penetrating keratoplasty (PK) and post-keratoprosthesis (KPro) surgery-related inflammation on the posterior segment of the eye and to assess inhibition of tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL-1β) on these effects. Methods BALB/C (syngeneic) or C57BL/6 (allogeneic) corneas were transplanted onto BALB/C host beds as part of PK or miniature KPro (m-KPro) implantation. Intraocular pressure (IOP) was measured via an intracameral pressure sensor; tissues were harvested and analyzed 8 weeks after surgery. Expression of TNFα and IL-1β in the retina was analyzed using real-time quantitative (q)PCR. Optic nerve degeneration (axon count, circularity, and area) was assessed quantitatively using ImageJ software. After m-KPro implantation, mice were treated with saline, anti-TNFα, or anti-IL-1β antibody, and axonal loss was assessed after 10 weeks. Results Mean IOP was within normal limits in the operated and fellow eyes in all groups. The mRNA expression of TNFα and IL-1β was highest in m-KPro groups with either syngeneic or an allogeneic carrier. We observed optic nerve degeneration in both allogeneic PK and m-KPro implanted eyes with an allogeneic carrier. However, TNFα blockade significantly reduced axonal loss by 35%. Conclusions Allogeneic PK and m-KPro implants with an allogeneic carrier lead to chronic inflammation in the posterior segment of the eye, resulting in optic nerve degeneration. In addition, blockade of TNFα prevents axonal degeneration in this preclinical model of allogeneic m-KPro (alloKPro) implantation. PMID:27054516

  1. Transdermal permeation of drugs with differing lipophilicity: Effect of penetration enhancer camphor.

    Science.gov (United States)

    Xie, Feng; Chai, Jia-Ke; Hu, Quan; Yu, Yong-Hui; Ma, Li; Liu, Ling-Ying; Zhang, Xu-Long; Li, Bai-Ling; Zhang, Dong-Hai

    2016-06-30

    The aim of the present study was to investigate the potential application of (+)-camphor as a penetration enhancer for the transdermal delivery of drugs with differing lipophilicity. The skin irritation of camphor was evaluated by in vitro cytotoxicity assays and in vivo transdermal water loss (TEWL) measurements. A series of model drugs with a wide span of lipophilicity (logP value ranging from 3.80 to -0.95), namely indometacin, lidocaine, aspirin, antipyrine, tegafur and 5-fluorouracil, were tested using in vitro transdermal permeation experiments to assess the penetration-enhancing profile of camphor. Meanwhile, the in vivo skin microdialysis was carried out to further investigate the enhancing effect of camphor on the lipophilic and hydrophilic model drugs (i.e. lidocaine and tegafur). SC (stratum corneum)/vehicle partition coefficient and Fourier transform infrared spectroscopy (FTIR) were performed to probe the regulation action of camphor in the skin permeability barrier. It was found that camphor produced a relatively low skin irritation, compared with the frequently-used and standard penetration enhancer laurocapram. In vitro skin permeation studies showed that camphor could significantly facilitate the transdermal absorption of model drugs with differing lipophilicity, and the penetration-enhancing activities were in a parabola curve going downwards with the drug logP values, which displayed the optimal penetration-enhancing efficiency for the weak lipophilic or hydrophilic drugs (an estimated logP value of 0). In vivo skin microdialysis showed that camphor had a similar penetration behavior on transdermal absorption of model drugs. Meanwhile, the partition of lipophilic drugs into SC was increased after treatment with camphor, and camphor also produced a shift of CH2 vibration of SC lipid to higher wavenumbers and decreased the peak area of the CH2 vibration, probably resulting in the alteration of the skin permeability barrier. This suggests that

  2. Penetration Enhancing Effect of Polysorbate 20 and 80 on the In ...

    African Journals Online (AJOL)

    Purpose: To investigate the penetration enhancing effect of two polysorbates - polyoxyethylene 20 (POE-20) and polyoxyethylene 80 (POE-80) - on the in vitro percutaneous absorption of ascorbic acid (AA). Methods: For the permeation experiments, Franz diffusion cell covered with aluminum foil providing an effective ...

  3. Effective Retinal Penetration of Lipophilic and Lipid-Conjugated Hydrophilic Agents Delivered by Engineered Liposomes.

    Science.gov (United States)

    Lee, Junsung; Goh, Unbyeol; Lee, Hyoung-Jin; Kim, Jiyoung; Jeong, Moonkyoung; Park, Ji-Ho

    2017-02-06

    Efficient delivery of drugs to the retina is critical but difficult to achieve with current methods. There have been a number of attempts to use intravitreal injection of liposomes, artificial vesicles composed of a phospholipid bilayer, to overcome the limitations of conventional intravitreal injection (short retention time, toxicity, poor penetration, etc.). Here, we report an optimal liposomal formulation that can diffuse through the vitreous humor, deliver the incorporated agents to all retinal layers effectively, and maintain them for a relatively long time. We first delivered lipophilic compounds and phospholipid-conjugated hydrophilic agents to the inner limiting membrane using engineered liposomes. Subsequently, the agents penetrated the retina deeply, presumably via extracellular vesicles, nanoscale vesicles secreted from retinal-associated cells. These results suggest that this engineered liposomal formulation can leverage the biological transport system for effective retinal penetration of lipophilic and lipid-conjugated agents.

  4. EFFECT OF TEMPERATURE AND HOST GENOTYPE ON ...

    African Journals Online (AJOL)

    Disease development in plants involves various inter-related processes each of which may be. influenced by environmental factors as well as host and pathogen genotypes Temperature in the range of 20~25°C was reported to be optimum for urediniospore germination of groundnut rust. (Subrahmanyam and McDonald ...

  5. The effect of penetrating trunk trauma and mechanical ventilation on ...

    African Journals Online (AJOL)

    2010-10-08

    Oct 8, 2010 ... Controls. Fig. 3. Dynamometry results for lower limbs at 6 months after discharge (data expressed as means) (L = left; R = right; Quads = quadriceps muscle; Hams = hamstring muscle; *p<0.05; SV = mechanical ventilation <5 days; LV = mechanical ventilation ≥5 days). The effect.indd 30. 8/10/10 8:40:01 ...

  6. Penetration enhancing effects of selected natural oils utilized in topical dosage forms.

    Science.gov (United States)

    Viljoen, Joe M; Cowley, Amé; du Preez, Jan; Gerber, Minja; du Plessis, Jeanetta

    2015-01-01

    Various natural products, including oils, have been utilized as penetration enhancers due to their "safety profiles". These oils contain fatty acids promoting skin permeability through lipid fluidization within the stratum corneum; and might therefore be able to effectively enhance transdermal drug delivery. We investigated possible penetration enhancing properties of selected oils, utilizing flurbiprofen as marker compound in emulgel formulations. The formulations were compared to a liquid paraffin emulgel and a hydrogel to establish any significant penetration enhancing effects. Gas chromatographic analysis of the natural oils was performed at ambient temperature to determine the fatty acid composition in each selected natural oils. Franz cell diffusion studies and tape stripping methods were employed to study delivery of the marker into, and through the skin. The following rank order for the emulgel flux-values was obtained: Hydrogel > olive oil > liquid paraffin > coconut oil > grape seed oil > Avocado oil ≥ Crocodile oil > Emu oil. Results suggested that oils containing predominantly mono-unsaturated oleic acid, on average increased the flux of the marker to a larger extent than oils containing an almost even mixture of both mono- and poly-unsaturated fatty acids. Oils comprising saturated fatty acids (SFAs) with alkyl chains between C12 and C14, increased the marker flux to a higher extent than oils containing C16-C18 SFAs. Effects observed for branched fatty acids, however, did not vary significantly from effects for unbranched fatty acids with the same carbon chain length. Natural oils possess penetration enhancing effects.

  7. The effect of different suturing techniques on astigmatism after penetrating keratoplasty.

    Science.gov (United States)

    Kim, Sang Jin; Wee, Won Ryang; Lee, Jin Hak; Kim, Mee Kum

    2008-12-01

    The purpose of this study was to compare the effects on astigmatism after penetrating keratoplasty with three different suture techniques. In this prospective study, 38 eyes of 38 patients underwent penetrating keratoplasty with three suturing techniques: interrupted, single running, and double running. Topographic astigmatism was measured at 2, 6, 12, and 18 months after keratoplasty. During 18 months after surgery, the interrupted suture group had higher astigmatism than the double running suture group. There was no significant difference in the amounts of astigmatism during the first year after keratoplasty between the single running and the double running suture group. However, at 18 months after surgery, when all sutures were out, the double running suture group (3.60+/-1.58 diopters) showed significantly less astigmatism than the single running group (5.65+/-1.61 diopters). In conclusion, post-keratoplasty astigmatism was the least in the double running suture group of the three suturing techniques at 18 months after penetrating keratoplasty.

  8. Effects of extratropical solar penetration on North Atlantic Ocean circulation and climate

    Science.gov (United States)

    Liang, Xi; Wu, Lixin

    2015-01-01

    Effects of extratropical solar penetration on the North Atlantic Ocean circulation and climate are investigated using a coupled ocean-atmosphere model. In this model, solar penetration generates basinwide cooling and warming in summer and winter, respectively. Associated with SST changes, annual mean surface wind stress is intensified in both the subtropical and subpolar North Atlantic, which leads to acceleration of both subtropical and subpolar gyres. Owing to warming in the subtropics and significant saltiness in the subpolar region, potential density decreases (increases) in the subtropical (subpolar) North Atlantic. The north-south meridional density gradient is thereby enlarged, accelerating the Atlantic meridional overturning circulation (AMOC). In addition, solar penetration reduces stratification in the upper ocean and favors stronger vertical convection, which also contributes to acceleration of the AMOC.

  9. Effects of egg shell quality and washing on Salmonella Infantis penetration.

    Science.gov (United States)

    Samiullah; Chousalkar, K K; Roberts, J R; Sexton, M; May, D; Kiermeier, A

    2013-07-15

    The vast majority of eggs in Australia are washed prior to packing to remove dirt and fecal material and to reduce the microbial contamination of the egg shell. The egg contents can be an ideal growth medium for microorganisms which can result in human illness if eggs are stored improperly and eaten raw or undercooked, and it is estimated that egg-related salmonellosis is costing Australia $44 million per year. Egg shell characteristics such as shell thickness, amount of cuticle present, and thickness of individual egg shell layers can affect the ease with which bacteria can penetrate the egg shell and washing could partially or completely remove the cuticle layer. The current study was conducted to investigate the effects of egg washing on cuticle cover and effects of egg shell quality and cuticle cover on Salmonella Infantis penetration of the egg shell. A higher incidence of unfavorable ultrastructural variables of the mammillary layer such as late fusion, type B bodies, type A bodies, poor cap quality, alignment, depression, erosion and cubics were recorded in Salmonella penetrated areas of egg shells. The influence of egg washing on the ability of Salmonella Infantis on the egg shell surface to enter the egg internal contents was also investigated using culture-based agar egg penetration and real-time qPCR based experiments. The results from the current study indicate that washing affected cuticle cover. There were no significant differences in Salmonella Infantis penetration of washed or unwashed eggs. Egg shell translucency may have effects on Salmonella Infantis penetration of the egg shell. The qPCR assay was more sensitive for detection of Salmonella Infantis from egg shell wash and internal contents than traditional microbiological methods. The agar egg and whole egg inoculation experiments indicated that Salmonella Infantis penetrated the egg shells. Egg washing not only can be highly effective at removing Salmonella Infantis from the egg shell surface

  10. A Preliminary Investigation of the Effect of Bumpers as a Means of Reducing Projectile Penetration

    Science.gov (United States)

    Funkhouser, John O.

    1961-01-01

    The results of an investigation to determine the effect of bumpers on projectile penetration indicate that for impact velocities up to 12,500 feet per second, the penetration of 0.062-inch-diameter copper projectiles in to aluminum targets can be definitely reduced by using a properly selected bumper spaced a short distance in front of the main target surface. Bumpers and main targets were made of 2024-T4 aluminum alloy, and spherical projectiles made of 0.062-inch-diameter copper were used in all tests.

  11. Effects of suture site or penetration depth on anchor location in all-inside meniscal repair.

    Science.gov (United States)

    Uchida, Ryohei; Mae, Tatsuo; Hiramatsu, Kunihiko; Iuchi, Ryo; Kinugasa, Kazutaka; Shino, Konsei; Yoshikawa, Hideki; Nakata, Ken

    2016-12-01

    To evaluate the effects of suture site or penetration depth on anchor location in all-inside meniscal repair. Eight fresh-frozen cadaveric knees were evaluated after meniscal repair using eight FasT-Fix360 (FF360) devices (Smith & Nephew Endoscopy, Andover, MA) (16 anchors) for each knee. The penetration depth was 14mm, the distance same from the periphery to insertion point, in four knees (Group A) and that in the remaining four knees (Group B) was 18mm. The anchor location in two groups was evaluated after attentive dissection. Of 32 anchors for the medial meniscus, 94% were on the capsule, including the superficial medial collateral ligament (sMCL) in both groups. For the lateral meniscus, 47% anchors in Group A and 44% anchors in Group B were on the capsule. Total three anchors were over the lateral collateral ligament (LCL), whereas 15 anchors were behind the popliteus tendon (POP). Although all three anchors settled in the subcutaneous fat were in Group B, no significant difference was observed in anchor location between two groups. Secure fixation to thin membranous tissue can be achieved for the medial meniscal repair using FF360, while some were located in/on bunchy LCL or POP in lateral meniscal repair. Only anchors with additional four-millimeter penetration depth were in the subcutaneous fat, although there was no effect of the penetration depth to anchor location. Clinically, for lateral meniscal repair, penetrating toward POP/LCL should be avoided and four-millimeter deeper penetration depth might be a risk for the subcutaneous irritation. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Transdermal drug delivery of labetalol hydrochloride: Feasibility and effect of penetration enhancers

    Directory of Open Access Journals (Sweden)

    Saqib Zafar

    2010-01-01

    Full Text Available Objectives : The objective of this study is to investigate the feasibility of transdermal drug delivery of Labetalol Hydrochloride (LHCl and to study the effect of different penetration enhancers on the skin permeability of LHCl. Methods : The permeability experiments were conducted using a horizontal glass diffusion cell with a diffusional area of 2.37 cm-2 on albino rat skin. The effect of various penetration enhancers namely turpentine oil, dimethyl formamide (DMF, menthol, dimethyl sulfoxide, pine oil, and 2-pyrollidone, and the effect of the concentration of drug and enhancer in the donor phase on the skin permeability of LHCl was studied. Results : The apparent partition coefficient of the drug was found to be 6.95, suggesting it to be a lipophilic drug. The preliminary skin permeation studies revealed that the permeation of LHCL through albino rat skin was moderate (Kp = 6.490 Χ 10 -2 cm hr -1 from isotonic phosphate buffer of pH 7.4. An appreciable increase in the LHCl permeability coefficient was observed on using a co-solvent (ethanol 95% with the penetration enhancers in the donor phase. DMSO (10% v/v was found to be the most effective enhancer for Labetalol hydrochloride (Enhancement Factor = 1.165. An increase in the concentration of drug and enhancer in the donor cell accentuated the permeability coefficient of LHCl. Conclusions : It was concluded that LHCl could be delivered via the dermal route with the use of 10% DMSO as the penetration enhancer.

  13. The Economic Effect of Education in an Information Technology-Penetrating Economy: Evidence from Hong Kong

    Science.gov (United States)

    Chan, Chi Wai

    2010-01-01

    This article examines the economic effect of education in terms of its impact on the earnings of workers in an information technology (IT)-diffusing economy, based on data from Hong Kong's 2006 by-census and survey on the usage and penetration of IT in industries. Education enhances the productivity of workers and increases their lifetime incomes.…

  14. The mechanical effects of different levels of cement penetration at the cement-bone interface

    NARCIS (Netherlands)

    Waanders, D.; Janssen, D.W.; Mann, K.A.; Verdonschot, Nicolaas Jacobus Joseph

    2010-01-01

    The mechanical effects of varying the depth of cement penetration in the cement–bone interface were investigated using finite element analysis (FEA) and validated using companion experimental data. Two FEA models of the cement–bone interface were created from micro-computed tomography data and the

  15. Effect of oral acyclovir after penetrating keratoplasty for herpetic keratitis: a placebo-controlled multicenter trial.

    NARCIS (Netherlands)

    Rooij, J.G.M. van; Rijneveld, W.J.; Remeijer, L.; Volker-Dieben, H.J.; Eggink, C.A.; Geerards, A.J.; Mulder, P.G.H.; Doornenbal, P.; Beekhuis, W.H.

    2003-01-01

    OBJECTIVE: To determine the prophylactic effect of oral acyclovir on the recurrence rate of herpetic eye disease after penetrating keratoplasty. DESIGN: A randomized, double-masked, placebo-controlled multicenter trial. PARTICIPANTS: Sixty-eight consecutive patients (68 eyes) with corneal opacities

  16. Nanocrystals for dermal penetration enhancement - Effect of concentration and underlying mechanisms using curcumin as model.

    Science.gov (United States)

    Vidlářová, Lucie; Romero, Gregori B; Hanuš, Jaroslav; Štěpánek, František; Müller, Rainer H

    2016-07-01

    Nanocrystals have received considerable attention in dermal application due to their ability to enhance delivery to the skin and overcome bioavailability issues caused by poor water and oil drug solubility. The objective of this study was to investigate the effect of nanocrystals on the mechanism of penetration behavior of curcumin as a model drug. Curcumin nanocrystals were produced by the smartCrystals® process, i.e. bead milling followed by high pressure homogenization. The mean particle size of the curcumin crystals was about 200nm. Stabilization was performed with alkyl polyglycoside surfactants. The distribution of curcumin within the skin was determined in vitro on cross-sections of porcine skin and visualized by fluorescent microscopy. The skin penetration profile was analyzed for the curcumin nanosuspension with decreasing concentrations (2%, 0.2%, 0.02% and 0.002% by weight) and compared to nanocrystals in a viscous hydroxypropylcellulose (HPC) gel. This study demonstrated there was minor difference between low viscous nanosuspension and the gel, but low viscosity seemed to favor skin penetration. Localization of curcumin was observed in the hair follicles, also contributing to skin uptake. Looking at the penetration of curcumin from formulations with decreasing nanocrystal concentration, formulations with 2%, 0.2% and 0.02% showed a similar penetration profile, whereas a significantly weaker fluorescence was observed in the case of a formulation containing 0.002% of curcumin nanocrystals. In this study we have shown that curcumin nanocrystals prepared by the smartCrystal® process are promising carriers in dermal application and furthermore, we identified the ideal concentration of 0.02% nanocrystals in dermal formulations. The comprehensive study of decreasing curcumin concentration in formulations revealed that the saturation solubility (Cs) is not the only determining factor for the penetration. A new mechanism based also on the concentration of the

  17. The Penetration Effects on Tandem-X Elevation Using the Gnss and Laser Altimetry Measurements in Antarctica

    Science.gov (United States)

    Zhao, J.; Floricioiu, D.

    2017-09-01

    Synthetic Aperture Radar (SAR) has been widely used in many different fields, such as geoscience, climate monitoring, security-related applications. However, over natural terrain the radar signal has the ability to penetrate the ground surface which can cause the bias in the elevation measurements. The aim of the paper is to assess the SAR signal penetration effect on the TanDEM-X absolute elevation over ice and snow covered areas and it presents the results concerning the X-band SAR signal penetration effect on dry snow areas and blue ice region. Additionally, the relationship between SAR signal penetration depth and backscattering coefficient is exploited and discussed. In this paper, two study sites, Schirmacher area and Recovery Ice Stream are selected and it is found that the general X-band SAR signal penetration depth is around 3-7 meter on dry snow area while no penetration depth is expected on the blue-ice region.

  18. Near-infrared photonic energy penetration: can infrared phototherapy effectively reach the human brain?

    Science.gov (United States)

    Henderson, Theodore A; Morries, Larry D

    2015-01-01

    Traumatic brain injury (TBI) is a growing health concern effecting civilians and military personnel. Research has yielded a better understanding of the pathophysiology of TBI, but effective treatments have not been forthcoming. Near-infrared light (NIR) has shown promise in animal models of both TBI and stroke. Yet, it remains unclear if sufficient photonic energy can be delivered to the human brain to yield a beneficial effect. This paper reviews the pathophysiology of TBI and elaborates the physiological effects of NIR in the context of this pathophysiology. Pertinent aspects of the physical properties of NIR, particularly in regards to its interactions with tissue, provide the background for understanding this critical issue of light penetration through tissue. Our recent tissue studies demonstrate no penetration of low level NIR energy through 2 mm of skin or 3 cm of skull and brain. However, at 10–15 W, 0.45%–2.90% of 810 nm light penetrated 3 cm of tissue. A 15 W 810 nm device (continuous or non-pulsed) NIR delivered 2.9% of the surface power density. Pulsing at 10 Hz reduced the dose of light delivered to the surface by 50%, but 2.4% of the surface energy reached the depth of 3 cm. Approximately 1.22% of the energy of 980 nm light at 10–15 W penetrated to 3 cm. These data are reviewed in the context of the literature on low-power NIR penetration, wherein less than half of 1% of the surface energy could reach a depth of 1 cm. NIR in the power range of 10–15 W at 810 and 980 nm can provide fluence within the range shown to be biologically beneficial at 3 cm depth. A companion paper reviews the clinical data on the treatment of patients with chronic TBI in the context of the current literature. PMID:26346298

  19. Ibrutinib Effective against Graft-Versus-Host Disease

    Science.gov (United States)

    A Cancer Currents blog post on results from a small clinical trial showing that ibrutinib can effectively treat graft-versus-host-disease, a common and serious complication of allogeneic stem cell transplants.

  20. Effect of sodium lauryl sulfate (SLS) on in vitro percutaneous penetration of water, hydrocortisone and nickel

    DEFF Research Database (Denmark)

    Frankild, S; Andersen, Klaus Ejner; Nielsen, Gunnar

    1995-01-01

    The dose- and time-related effect of sodium lauryl sulfate (SLS) on in vitro percutaneous penetration was studied using 3 radiolabeled tracer compounds with different physicochemical properties: tritiated water, hydrocortisone and nickel. Human cadaver abdominal skin from caucasian women was used....../damaging effect on the skin barrier. It should be kept in mind that the model uses a dead skin membrane without the barrier repair mechanisms of live skin....

  1. Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment.

    Science.gov (United States)

    Leite-Silva, V R; Sanchez, W Y; Studier, H; Liu, D C; Mohammed, Y H; Holmes, A M; Ryan, E M; Haridass, I N; Chandrasekaran, N C; Becker, W; Grice, J E; Benson, H A E; Roberts, M S

    2016-07-01

    Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaired skin of volunteers, without or with occlusion. We also observed no apparent toxicity in the viable epidermis below the application sites. These findings were validated by ex vivo human skin studies in which zinc penetration was assessed by multiphoton tomography with fluorescence lifetime imaging as well as Zinpyr-1 staining and toxicity was assessed by MTS assays in zinc oxide treated skin cryosections. In conclusion, applications of zinc oxide nanoparticles under occlusive in-use conditions to volunteers are not associated with any measurable zinc oxide penetration into, or local toxicity in the viable epidermis below the application site. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Effect of Different Irrigation Systems on Sealer Penetration into Dentinal Tubules.

    Science.gov (United States)

    Generali, Luigi; Cavani, Francesco; Serena, Valentina; Pettenati, Corinne; Righi, Elena; Bertoldi, Carlo

    2017-04-01

    Different irrigation systems have been developed to improve the efficacy and distribution of the irrigants. The aim of this study was to compare the effect of conventional endodontic needle irrigation with other irrigant delivery and/or agitation systems on sealer penetration into dentinal tubules. Fifty single-rooted teeth with round-shaped root canals were distributed in 5 homogeneous groups characterized by the different cleansing system used: conventional endodontic needle irrigation, EndoActivator, Irrisafe, Self-Adjusting File, and EndoVac. After instrumentation, all teeth were filled by Thermafil obturators and rhodamine B dye labeled TopSeal sealer. Teeth were transversally sectioned at 2-, 5-, and 7-mm levels from the apex and observed under confocal laser scanning microscope. Maximum, mean, and percentage of sealer penetration inside tubules around the root canal were measured. Moreover, the integrity of the sealer layer perimeter was evaluated. No significant differences both in mean (p > .05) and in maximum penetration depth (p > .05) were observed among groups, whereas both parameters showed an increased trend within each group from the 2- to the 7-mm level from apex. Similarly, the percentage of penetration around the root canal wall did not differ among groups (p > .05) and showed an increasing trend within each group from the apical to the coronal portion of the canal. Sealer penetration into dentinal tubules is not affected by the irrigant delivery and/or agitation systems studied. Thermafil with TopSeal technique achieves complete sealer perimeter integrity in all groups. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. Screening Effect of Plasma Flow on RMP Penetration in EXTRAP T2R

    Science.gov (United States)

    Frassinetti, Lorenzo; Olofsson, Erik; Brunsell, Per; Menmuir, Sheena; Drake, James

    2011-10-01

    The penetration of resonant magnetic perturbations (RMP) can be screened by plasma flow and the understanding of this phenomenon is important for ELM mitigation techniques. This work studies the screening effect in EXTRAP T2R. EXTRAP T2R is equipped with a feedback system able to suppress all error fields and to produce one or more external perturbations in a controlled fashion. The EXTRAP T2R feedback system is used to generate a RMP that interacts with the dynamics of its corresponding tearing mode (TM). The level of RMP penetration is quantified by analyzing the RMP effect on the TM amplitude and velocity. To study the screening effect, the flow is changed by applying a second perturbation that is non resonant (non-RMP). This produces the flow reduction without perturbing significantly the other parameters. By modifying the amplitude of the non-RMP, an experimental study of the flow effect on the RMP penetration is performed. Experimental results are compared with the model described in [Fitzpatrick R et al., Phys. Plasmas 8, 4489 (2001)].

  4. Effective thermal penetration depth in photo-irradiated ex vivo human tissues.

    Science.gov (United States)

    Stolik, Suren; Delgado, José Alberto; Anasagasti, Lorenzo; Pérez, Arllene Mariana

    2011-10-01

    In this work, a model of bioheat distribution is discussed for ex vivo human tissue samples, and the thermal penetration depth measurements performed on several tissues are presented. Optical radiation is widely applied in the treatment and diagnosis of different pathologies. A power density of incident light at 100 mW/cm(2) is sufficiently high enough to induce a temperature increase of >5°C in irradiated human tissue. In this case, knowledge of the thermal properties of the tissue is needed to achieve a better understanding of the therapeutic effects. The application of the diffusion approximation of the radiative transfer equation for the distribution of optical radiation, the experimental setup, and the results thereof are presented and discussed. The effective thermal penetration depth in the studied tissues has been determined to be in the range of 4.3-7.0 mm. The effective thermal penetration depth has been defined, and this could be useful for developing models to describe the thermal effects with a separate analysis of the tissue itself and the blood that irrigates it.

  5. Insurance penetration and economic growth in Africa: Dynamic effects analysis using Bayesian TVP-VAR approach

    Directory of Open Access Journals (Sweden)

    D.O. Olayungbo

    2016-12-01

    Full Text Available This paper examines the dynamic interactions between insurance and economic growth in eight African countries for the period of 1970–2013. Insurance demand is measured by insurance penetration which accounts for income differences across the sample countries. A Bayesian Time Varying Parameter Vector Auto regression (TVP-VAR model with stochastic volatility is used to analyze the short run and the long run among the variables of interest. Using insurance penetration as a measure of insurance to economic growth, we find positive relationship for Egypt, while short-run negative and long-run positive effects are found for Kenya, Mauritius, and South Africa. On the contrary, negative effects are found for Algeria, Nigeria, Tunisia, and Zimbabwe. Implementation of sound financial reforms and wide insurance coverage are proposed recommendations for insurance development in the selected African countries.

  6. Percutaneous penetration enhancement effect of essential oil of mint (Mentha haplocalyx Briq. on Chinese herbal components with different lipophilicity

    Directory of Open Access Journals (Sweden)

    Jingyan Wang

    2014-10-01

    Conclusions: Mint oil at proper concentration could effectively facilitate percutaneous penetration of both lipophilic and hydrophilic drugs, and exhibit higher efficiency for moderate hydrophilic drugs. Mechanisms of penetration enhancement by mint oil could be explained with saturation solubility, SC/vehicle partition coefficient and the secondary structure change of SC.

  7. Multifaceted effects of host plants on entomopathogenic nematodes.

    Science.gov (United States)

    Hazir, Selcuk; Shapiro-Ilan, David I; Hazir, Canan; Leite, Luis G; Cakmak, Ibrahim; Olson, Dawn

    2016-03-01

    The success of parasites can be impacted by multi-trophic interactions. Tritrophic interactions have been observed in parasite-herbivore-host plant systems. Here we investigate aspects of multi-trophic interactions in a system involving an entomopathogenic nematode (EPN), its insect host, and host plant. Novel issues investigated include the impact of tritrophic interactions on nematode foraging behavior, the ability of EPNs to overcome negative tritrophic effects through genetic selection, and interactions with a fourth trophic level (nematode predators). We tested infectivity of the nematode, Steinernema riobrave, to corn earworm larvae (Helicoverpa zea) in three host plants, tobacco, eggplant and tomato. Tobacco reduced nematode virulence and reproduction relative to tomato and eggplant. However, successive selection (5 passages) overcame the deficiency; selected nematodes no longer exhibited reductions in phenotypic traits. Despite the loss in virulence and reproduction nematodes, first passage S. riobrave was more attracted to frass from insects fed tobacco than insects fed on other host plants. Therefore, we hypothesized the reduced virulence and reproduction in S. riobrave infecting tobacco fed insects would be based on a self-medicating tradeoff, such as deterring predation. We tested this hypothesis by assessing predatory success of the mite Sancassania polyphyllae and the springtail Sinella curviseta on nematodes reared on tobacco-fed larvae versus those fed on greater wax moth, Galleria mellonella, tomato fed larvae, or eggplant fed larvae. No advantage was observed in nematodes derived from tobacco fed larvae. In conclusion, our results indicated that insect-host plant diet has an important effect on nematode foraging, infectivity and reproduction. However, negative host plant effects, might be overcome through directed selection. We propose that host plant species should be considered when designing biocontrol programs using EPNs. Copyright © 2016

  8. Field Test Evaluation of Effect on Cone Resistance Caused by Change in Penetration Rate

    DEFF Research Database (Denmark)

    Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2012-01-01

    This paper presents how a change in cone penetration rate affects the measured cone resistance during cone penetration testing in silty soils. Regardless of soil, type the standard rate of penetration is 20 mm/s and it is generally accepted that undrained penetration occurs in clay while drained...... in the laboratory. A change in the measured cone resistance occurs by lowering the penetration rate. This is caused by the changes in drainage conditions. Compared to the normal penetration rate of 20 mm/s, this paper illustrates that lowering the penetration rate leads to an increase in the cone resistance from 1...

  9. Transdermal delivery of dimethyl fumarate for Alzheimer's disease: Effect of penetration enhancers.

    Science.gov (United States)

    Ameen, Dina; Michniak-Kohn, Bozena

    2017-08-30

    Dimethyl fumarate (DMF) is an orally administered drug with neuroprotective and immunomodulatory activities. It has potential uses in the treatment of neurodegenerative diseases such as Alzheimer's disease (AD). The objective of this study was to investigate the feasibility of transdermal delivery of DMF by studying the effect of different penetration enhancers on the skin permeation of DMF. The permeation of saturated DMF solutions was investigated in propylene glycol (PG) with varying concentrations of each of the following enhancers: Polysorbate 80 (T80), N-methyl pyrrolidone (NMP), laurocapram (Azone ®) (Az), Transcutol P (Tc), Terpineol (Terp), and cineole (Cin) using vertical Franz diffusion cells and human cadaver skin. The results showed that all penetration enhancers improved the rate of permeation of DMF. The rank order for the highest concentration of each enhancer was as follows: Cin > Az>TC > Terp>T80≥NMP. The most effective penetration enhancer was shown to be 5% cineole with a 5.3-fold increase in the enhancement ratio (ER). The amounts of drug delivered suggest that DMF is a potential candidate for transdermal drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Comparative analysis of the effects of CO2 fractional laser and sonophoresis on human skin penetration with 5-aminolevulinic acid.

    Science.gov (United States)

    Choi, J H; Shin, E J; Jeong, K H; Shin, M K

    2017-11-01

    Successful delivery of a photosensitizer into the skin is an important factor for effective photodynamic therapy (PDT). The effective method to increase drug penetration within short incubation time overcoming skin barrier have been investigated. This study was performed to analyze and compare the effectiveness of ablative fractional laser (FXL) pretreatment and/or sonophoresis for enhancing the penetration of 5-aminolevulinic acid (ALA) into human skin in vivo. Twenty-four identical 1 × 1 cm(2) treatment areas were mapped on the backs of ten healthy male subjects. Each area received FXL pretreatment and/or sonophoresis with different energy settings and ALA incubation times. After treatments, porphyrin fluorescence reflecting the ALA penetration were measured. Application of ablative CO2 FXL pretreatment resulted to higher fluorescence intensities than the non-treatment group. Incubation times were positively correlated with the increments of ALA penetration. However, increasing pulse energy or combining with sonophoresis did not show additional positive effects on ALA penetration. Ablative CO2 FXL pretreatment effectively facilitated ALA penetration in human skin in vivo. Ablative CO2 FXL alone without sonophoresis setting pulse energy of 10 and 20 mJ with more than 60 min of ALA incubation time could be an ideal setting for ALA penetration.

  11. Microscopic Driving Parameters-Based Energy-Saving Effect Analysis under Different Electric Vehicle Penetration

    Directory of Open Access Journals (Sweden)

    Enjian Yao

    2013-01-01

    Full Text Available Due to the rapid motorization over the recent years, China's transportation sector has been facing an increasing environmental pressure. Compared with gasoline vehicle (GV, electric vehicle (EV is expected to play an important role in the mitigation of CO2 and other pollution emissions, and urban air quality improvement, for its zero emission during use and higher energy efficiency. This paper aims to estimate the energy saving efficiency of EV, especially under different EV penetration and road traffic conditions. First, based on the emission and electricity consumption data collected by a light-duty EV and a light duty GV, a set of electricity consumption rate models and gasoline consumption rate models are established. Then, according to the conversion formula of coal equivalent, these models are transformed into coal equivalent consumption models, which make gasoline consumption and electricity consumption comparable. Finally, the relationship between the EV penetration and the reduction of energy consumption is explored based on the simulation undertaken on the North Second Ring Road in Beijing. The results show that the coal equivalent consumption will decrease by about 5% with the increases of EV penetration by 10% and the maximum energy-saving effect can be achieved when the traffic volume is about 4000 pcu/h.

  12. Effect of Different Irrigating Solutions on Depth of Penetration of Sealer into Dentinal Tubules: A Confocal Microscopic Study.

    Science.gov (United States)

    Thota, Murali Mohan; Sudha, Kakollu; Malini, D L; Madhavi, Singiri Bindhu

    2017-01-01

    The aim of the study was to evaluate the effect of different irrigating solutions used in final irrigation on depth of sealer penetration into dentinal tubules. Thirty recently extracted, human mandibular premolar teeth with single canals were randomly divided into two groups, and one of the two irrigants was used in each group - Group A (Chitosan) and Group B (Ethylenediaminetetraacetic acid). All the teeth were obturated with gutta-percha and AH 26(®) sealer labeled with fluorescent dye. The teeth were sectioned at distances 2, 5, and 8 mm from the root apex. Maximum depth of sealer penetration was measured using confocal laser scanning microscopy. Statistical analysis used One-way analysis of variance and t-test. At coronal third depth, the sealer penetration was greater in ethylenediaminetetraacetic acid (EDTA) group; however, depth of sealer penetration was greater at apical third in chitosan group. Final irrigation with EDTA and chitosan after the use of sodium hypochlorite affected sealer penetration.

  13. Effect of Host Condition on Intestinal Parasite Load and Prevalence ...

    African Journals Online (AJOL)

    Host condition had effect on therate of infection and greater effect on intestinal parasite load in Malapterurus electricus . These vary among sex, sizes and weights of conspecific individuals. This was investigated over a period of two years.A total of 340 fishes from the lagoon were caught and dissected for intestinal helminth ...

  14. The barley (Hordeum vulgare) cellulose synthase-like D2 gene (HvCslD2) mediates penetration resistance to host-adapted and nonhost isolates of the powdery mildew fungus.

    Science.gov (United States)

    Douchkov, Dimitar; Lueck, Stefanie; Hensel, Goetz; Kumlehn, Jochen; Rajaraman, Jeyaraman; Johrde, Annika; Doblin, Monika S; Beahan, Cherie T; Kopischke, Michaela; Fuchs, René; Lipka, Volker; Niks, Rients E; Bulone, Vincent; Chowdhury, Jamil; Little, Alan; Burton, Rachel A; Bacic, Antony; Fincher, Geoffrey B; Schweizer, Patrick

    2016-10-01

    Cell walls and cellular turgor pressure shape and suspend the bodies of all vascular plants. In response to attack by fungal and oomycete pathogens, which usually breach their host's cell walls by mechanical force or by secreting lytic enzymes, plants often form local cell wall appositions (papillae) as an important first line of defence. The involvement of cell wall biosynthetic enzymes in the formation of these papillae is still poorly understood, especially in cereal crops. To investigate the role in plant defence of a candidate gene from barley (Hordeum vulgare) encoding cellulose synthase-like D2 (HvCslD2), we generated transgenic barley plants in which HvCslD2 was silenced through RNA interference (RNAi). The transgenic plants showed no growth defects but their papillae were more successfully penetrated by host-adapted, virulent as well as avirulent nonhost isolates of the powdery mildew fungus Blumeria graminis. Papilla penetration was associated with lower contents of cellulose in epidermal cell walls and increased digestion by fungal cell wall degrading enzymes. The results suggest that HvCslD2-mediated cell wall changes in the epidermal layer represent an important defence reaction both for nonhost and for quantitative host resistance against nonadapted wheat and host-adapted barley powdery mildew pathogens, respectively. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  15. Evaluation of the Effective Moisture Penetration Depth Model for Estimating Moisture Buffering in Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Woods, J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Winkler, J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Christensen, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-01-01

    This study examines the effective moisture penetration depth (EMPD) model, and its suitability for building simulations. The EMPD model is a compromise between the simple, inaccurate effective capacitance approach and the complex, yet accurate, finite-difference approach. Two formulations of the EMPD model were examined, including the model used in the EnergyPlus building simulation software. An error in the EMPD model we uncovered was fixed with the release of EnergyPlus version 7.2, and the EMPD model in earlier versions of EnergyPlus should not be used.

  16. Studying the effectiveness of penetration enhancers to deliver retinol through the stratum cornum by in vivo confocal Raman spectroscopy.

    Science.gov (United States)

    Mélot, Mickaël; Pudney, Paul D A; Williamson, Ann-Marie; Caspers, Peter J; Van Der Pol, Andre; Puppels, Gerwin J

    2009-08-19

    The purpose of this study is to monitor in vivo the effect of chemical penetration enhancers on the delivery of trans-retinol into human skin. Chemical penetration enhancers reversibly alter barrier properties of the SC by disruption of the membrane structures or maximising drug solubility with the skin. So far, most of permeation or penetration experiments are performed in vitro. Raman spectroscopy is uniquely placed to be able to measure biological processes in vivo and this paper shows for the first time that the effect of penetration enhancer on the delivery of trans-retinol can successfully be measured in vivo using this technique. Here, the volar forearm of volunteers was treated with four formulations. One formulation is a highly effective model delivery system identified from ex vivo experiments: trans-retinol in Propylene Glycol (PG)/ethanol, with PG being a well-known and efficient penetration enhancer. The other three formulations are based on 0.3% trans-retinol in Caprylic/Capric Acid Triglyceride (MYRITOL 318), an oil commonly used in skin creams but in two of them a specific penetration enhancer is added. One contains a lipid extractor, Triton X 100, whereas another formulation contains a lipid fluidiser, Oleic Acid. Solutions were applied once and measurements were performed up to 6 h after treatment. Remarkable differences in the delivery of trans-retinol between formulation with or without penetration enhancer can clearly be seen. Moreover, the type of penetration enhancer is also shown to influence the delivery. While using the Oleic Acid, which is a lipid fluidiser, a better delivery of trans-retinol in the skin can be detected. For the first time, the effect of penetration enhancer on the delivery of trans-retinol has been monitored, non invasively in vivo, with time.

  17. Host Genetic and Environmental Effects on Mouse Cecum Microbiota

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, James H [ORNL; Foster, Carmen M [ORNL; Vishnivetskaya, Tatiana A [ORNL; Campbell, Alisha G [ORNL; Yang, Zamin Koo [ORNL; Wymore, Ann [ORNL; Palumbo, Anthony Vito [ORNL; Podar, Mircea [ORNL

    2012-01-01

    The mammalian gut harbors complex and variable microbial communities, across both host phylogenetic space and conspecific individuals. A synergy of host genetic and environmental factors shape these communities and account for their variability, but their individual contributions and the selective pressures involved are still not well understood. We employed barcoded pyrosequencing of V1-2 and V4 regions of bacterial small subunit ribosomal RNA genes to characterize the effects of host genetics and environment on cecum assemblages in 10 genetically distinct, inbred mouse strains. Eight of these strains are the foundation of the Collaborative Cross (CC), a panel of mice derived from a genetically diverse set of inbred founder strains, designed specifically for complex trait analysis. Diversity of gut microbiota was characterized by complementing phylogenetic and distance-based, sequence-clustering approaches. Significant correlations were found between the mouse strains and their gut microbiota, reflected by distinct bacterial communities. Cohabitation and litter had a reduced, although detectable effect, and the microbiota response to these factors varied by strain. We identified bacterial phylotypes that appear to be discriminative and strain-specific to each mouse line used. Cohabitation of different strains of mice revealed an interaction of host genetic and environmental factors in shaping gut bacterial consortia, in which bacterial communities became more similar but retained strain specificity. This study provides a baseline analysis of intestinal bacterial communities in the eight CC progenitor strains and will be linked to integrated host genotype, phenotype and microbiota research on the resulting CC panel.

  18. The Effects of Hygrothermal Aging on the Impact Penetration Resistance of Triaxially Braided Composites

    Science.gov (United States)

    Pereira, J. Michael; Revilock, Duane M.; Ruggeri, Charles R.; Roberts, Gary D.; Kohlman, Lee W.; Miller, Sandi G.

    2016-01-01

    An experimental study was conducted to measure the effects of long term hygrothermal aging on the impact penetration resistance of triaxially braided polymer composites. Flat panels of three different materials were subjected to repeated cycles of high and low temperature and high and low humidity for two years. Samples of the panels were periodically tested under impact loading during the two year time period. The purpose of the study was to identify and quantify any degradation in impact penetration resistance of these composites under cyclic temperature and humidity conditions experienced by materials in the fan section of commercial gas turbine engines for a representative aircraft flight cycle. The materials tested consisted of Toray ® T700S carbon fibers in a 2D triaxial braid with three different resins, Cycom® PR520, a toughened resin, Hercules® 3502, an untoughened resin and EPON 862, intermediate between the two. The fiber preforms consisted of a quasi-isotropic 0/+60/-60 braid with 24K tows in the axial direction and 12K tows in the bias directions. The composite panels were manufactured using a resin transfer molding process producing panels with a thickness of 0.125 inches. The materials were tested in their as-processed condition and again after one year and two years of aging (1.6 years in the case of E862). The aging process involved subjecting the test panels to two cycles per day of high and low temperature and high and low humidity. A temperature range of -60degF to 250degF and a humidity range of 0 to 85% rh was used to simulate extreme conditions for composite components in the fan section of a commercial gas turbine engine. Additional testing was conducted on the as-processed PR520 composite under cryogenic conditions. After aging there was some change in the failure pattern, but there was no reduction in impact penetration threshold for any of the three systems, and in the case of the 3502 system, a significant increase in penetration

  19. Bidirectional anatomical effects in a mistletoe-host relationship: Psittacanthus schiedeanus mistletoe and its hosts Liquidambar styraciflua and Quercus germana.

    Science.gov (United States)

    Cocoletzi, Eliezer; Angeles, Guillermo; Ceccantini, Gregório; Patrón, Araceli; Ornelas, Juan Francisco

    2016-06-01

    During the interactions between a parasitic plant and its host, the parasite affects its host morphologically, anatomically, and physiologically, yet there has been little focus on the effect of hosts on the parasite. Here, the functional interactions between the hemiparasitic mistletoe Psittacanthus schiedeanus and its hosts Liquidambar styraciflua and Quercus germana were interpreted based on the anatomical features of the vascular tissues. Using standard techniques for light and transmission electron microscopy, we studied the effects of P. schiedeanus on the phloem anatomy of Liquidambar styraciflua and Quercus germana and vice versa. The phloem of P. schiedeanus has larger sieve elements, companion cells, and sieve plate areas when it is parasitizing L. styraciflua than Q. germana; however, the parasite produces systemic effects on the phloem of its hosts, reducing the size of phloem in L. styraciflua but increasing it in Q. germana. Those seem to be the bidirectional effects. No direct connections between the secondary phloem of the parasite and that of its hosts were observed. Parenchymatic cells of L. styraciflua in contact with connective parenchyma cells of the parasite develop half-plasmodesmata, while those of Q. germana do not. The bidirectional effects between the parasite and its hosts comprise modifications in secondary phloem that are potentially affected by the phenology of its hosts, a combination of hormonal agents such as auxins, and the symplasmic or apoplasmic pathway for solutes import. © 2016 Botanical Society of America.

  20. Effect of tool rotational speed and penetration depth on dissimilar aluminum alloys friction stir spot welds

    Directory of Open Access Journals (Sweden)

    Joaquín M. Piccini

    2017-03-01

    Full Text Available In the last years, the automotive industry is looking for the use of aluminum parts in replace of steel parts in order to reduce the vehicles weight. These parts have to be joined, for instance, by welding processes. The more common welding process in the automotive industry is the Resistance Spot Welding (RSW technique. However, RSW of aluminum alloys has many disadvantages. Regarding this situation, a variant of the Friction Stir Welding process called Friction Stir Spot Welding (FSSW has been developed, showing a strong impact in welding of aluminum alloys and dissimilar materials in thin sheets. Process parameters affect the characteristics of the welded joints. However, the information available on this topic is scarce, particularly for dissimilar joints and thin sheets. The aim of this work was to study the effect of the rotational speed and the tool penetration depth on the characteristics of dissimilar FSS welded joints. Defects free joints have been achieved with higher mechanical properties than the ones reported. The maximum fracture load was 5800 N. It was observed that the effective joint length of the welded spots increased with the tool penetration depth, meanwhile the fracture load increased and then decreased. Finally, welding at 1200 RPM produced welded joints with lower mechanical properties than the ones achieved at 680 and 903 RPM.

  1. Effect of Size, Surface Charge, and Hydrophobicity of Poly(amidoamine) Dendrimers on Their Skin Penetration

    Science.gov (United States)

    Yang, Yang; Sunoqrot, Suhair; Stowell, Chelsea; Ji, Jingli; Lee, Chan-Woo; Kim, Jin Woong; Khan, Seema A.; Hong, Seungpyo

    2012-01-01

    The barrier functions of the stratum corneum (SC) and the epidermal layers present a tremendous challenge in achieving effective transdermal delivery of drug molecules. Although a few reports have shown that poly(amidoamine) (PAMAM) dendrimers are effective skin penetration enhancers, little is known regarding the fundamental mechanisms behind the dendrimer-skin interactions. In this paper, we have performed a systematic study to better elucidate how dendrimers interact with skin layers depending on their size and surface groups. Franz diffusion cells and confocal microscopy were employed to observe dendrimer interactions with full-thickness porcine skin samples. We have found that smaller PAMAM dendrimers (generation 2 (G2)) penetrate the skin layers more efficiently than the larger ones (G4). We have also found that G2 PAMAM dendrimers that are surface modified by either acetylation or carboxylation exhibit increased skin permeation and likely diffuse through an extracellular pathway. In contrast, amine-terminated dendrimers show enhanced cell internalization and skin retention but reduced skin permeation. In addition, conjugation of oleic acid (OA) to G2 dendrimers increases their 1-octanol/PBS partition coefficient, resulting in increased skin absorption and retention. Here we report that size, surface charge, and hydrophobicity directly dictate the permeation route and efficiency of dendrimer translocation across the skin layers, providing a design guideline for engineering PAMAM dendrimers as a potential transdermal delivery vector. PMID:22621160

  2. Evaluation of skin permeation and analgesic activity effects of carbopol lornoxicam topical gels containing penetration enhancer.

    Science.gov (United States)

    Al-Suwayeh, Saleh A; Taha, Ehab I; Al-Qahtani, Fahad M; Ahmed, Mahrous O; Badran, Mohamed M

    2014-01-01

    The current study was designed to develop a topical gel formulation for improved skin penetration of lornoxicam (LOR) for enhancement of its analgesic activity. Moreover, the effect of different penetration enhancers on LOR was studied. The LOR gel formulations were prepared by using hydroxylpropyl methylcellulose (HPMC) and carbopol. The carbopol gels in presence of propylene glycol (PG) and ethanol were developed. The formulated gels were characterized for pH, viscosity, and LOR release using Franz diffusion cells. Also, in vitro skin permeation of LOR was conducted. The effect of hydroxypropyl β-cyclodextrin (HP β-CD), beta-cyclodextrin (β-CD), Tween 80, and oleic acid on LOR permeation was evaluated. The optimized LOR gel formulation (LORF8) showed the highest flux (14.31 μg/cm(2)/h) with ER of 18.34 when compared to LORF3. Incorporation of PG and HP β-CD in gel formulation (LORF8) enhanced the permeation of LOR significantly. It was observed that LORF3 and LORF8 show similar analgesic activity compared to marketed LOR injection (Xefo). This work shows that LOR can be formulated into carbopol gel in presence of PG and HP β-CD and may be promising in enhancing permeation.

  3. Evaluation of Skin Permeation and Analgesic Activity Effects of Carbopol Lornoxicam Topical Gels Containing Penetration Enhancer

    Directory of Open Access Journals (Sweden)

    Saleh A. Al-Suwayeh

    2014-01-01

    Full Text Available The current study was designed to develop a topical gel formulation for improved skin penetration of lornoxicam (LOR for enhancement of its analgesic activity. Moreover, the effect of different penetration enhancers on LOR was studied. The LOR gel formulations were prepared by using hydroxylpropyl methylcellulose (HPMC and carbopol. The carbopol gels in presence of propylene glycol (PG and ethanol were developed. The formulated gels were characterized for pH, viscosity, and LOR release using Franz diffusion cells. Also, in vitro skin permeation of LOR was conducted. The effect of hydroxypropyl β-cyclodextrin (HP β-CD, beta-cyclodextrin (β-CD, Tween 80, and oleic acid on LOR permeation was evaluated. The optimized LOR gel formulation (LORF8 showed the highest flux (14.31 μg/cm2/h with ER of 18.34 when compared to LORF3. Incorporation of PG and HP β-CD in gel formulation (LORF8 enhanced the permeation of LOR significantly. It was observed that LORF3 and LORF8 show similar analgesic activity compared to marketed LOR injection (Xefo. This work shows that LOR can be formulated into carbopol gel in presence of PG and HP β-CD and may be promising in enhancing permeation.

  4. Vehicle and enhancer effects on human skin penetration of aminophylline from cream formulations: evaluation in vivo.

    Science.gov (United States)

    Wang, Lai-Hao; Wang, Chia-Chen; Kuo, Su-Ching

    2007-01-01

    The effects of four essential oils (rosemary, ylang, lilacin, and peppermint oils), and three plant oils (jojoba oil, corn germ oil, and olive oil) on the permeation of aminophylline were studied using human skin. The permeation effects of these oils were compared with those of three chemical penetration enhancers. Although all oils enhanced the permeation of aminophylline, their effects were less than that of ethanol. Jojoba oil was found to be the most active, causing about a 32% peak height decrease of N-H bending absorbances in comparison with the control, while peppermint, lilacin, rosemary, and ylang oils caused 28%, 24%, 18%, and 12% peak height decreases, respectively. Microemulsions containing 10% jojoba oil and 30% corn germ oil were found to be superior vehicles for the percutaneous absorption of aminophylline. Comparision with results obtained from high-performance liquid chromatography shows good agreement.

  5. Femtosecond Laser-Assisted Intrastromal Relaxing Incisions After Penetrating Keratoplasty: Effect of Incision Depth.

    Science.gov (United States)

    Wetterstrand, Olli; Holopainen, Juha M; Krootila, Kari

    2015-07-01

    To correlate the efficacy of femtosecond laser-assisted intrastromal relaxing incisions after penetrating keratoplasty with the posterior depth of corneal incisions. Twenty eyes of 20 patients were treated for regular postoperative penetrating keratoplasty astigmatism. Sutures had been removed and refraction had stabilized. Ultrasound pachymetry was used to calculate incisional depth. Femtosecond laser-assisted paired arcuate incisions were made inside the graft stroma, leaving 90 µm of intact anterior cornea including epithelium. The intact posterior corneal margin was 10% of the measured corneal thickness for 10 patients (10% group) and 125 µm for the remaining 10 patients (125-µm group). Follow-up visits consisted of biomicroscopy, intraocular pressure measurement, fundus examination, and topographic evaluation using anterior segment optical coherence tomography at 1 and 3 months. Postoperative corneal thickness and the depth of incisions were measured with optical coherence tomography. Corrected distance visual acuity improved from 0.5 to 0.3 logMAR (Snellen: 20/63 to 20/40, P astigmatism (P incisions is correlated with the posterior depth of the incisions. The deeper incisions were more effective. Copyright 2015, SLACK Incorporated.

  6. Production of dissolvable microneedles using an atomised spray process: effect of microneedle composition on skin penetration.

    Science.gov (United States)

    McGrath, Marie G; Vucen, Sonja; Vrdoljak, Anto; Kelly, Adam; O'Mahony, Conor; Crean, Abina M; Moore, Anne

    2014-02-01

    Dissolvable microneedles offer an attractive delivery system for transdermal drug and vaccine delivery. They are most commonly formed by filling a microneedle mold with liquid formulation using vacuum or centrifugation to overcome the constraints of surface tension and solution viscosity. Here, we demonstrate a novel microneedle fabrication method employing an atomised spray technique that minimises the effects of the liquid surface tension and viscosity when filling molds. This spray method was successfully used to fabricate dissolvable microneedles (DMN) from a wide range of sugars (trehalose, fructose and raffinose) and polymeric materials (polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylmethylcellulose and sodium alginate). Fabrication by spraying produced microneedles with amorphous content using single sugar compositions. These microneedles displayed sharp tips and had complete fidelity to the master silicon template. Using a method to quantify the consistency of DMN penetration into different skin layers, we demonstrate that the material of construction significantly influenced the extent of skin penetration. We demonstrate that this spraying method can be adapted to produce novel laminate-layered as well as horizontally-layered DMN arrays. To our knowledge, this is the first report documenting the use of an atomising spray, at ambient, mild processing conditions, to create dissolvable microneedle arrays that can possess novel, laminate layering. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Effect of internal short fibers, steel reinforcement, and surface layer on impact and penetration resistance of concrete

    Directory of Open Access Journals (Sweden)

    Ali Abd_Elhakam Aliabdo

    2013-09-01

    Full Text Available This paper presents an experimental program to investigate the impact and penetration resistance of concrete. The research work is divided into two approaches. These approaches are effect of concrete constituents and effect of surface layer. Effect of concrete aggregate type, w/c ratio, fiber type, fiber shape, fiber volume fraction, and steel reinforcement is considered in the first approach. The second approach includes using fiber reinforced concrete and glass fiber reinforced polymer as surface layers. The evaluating tests include standard impact test according to ASTM D 1557 and suggested simulated penetration test to measure the impact and penetration resistance of concrete. The test results of plain and fibrous concrete from ASTM D 1557 method indicated that steel fiber with different configurations and using basalt have a great positive effect on impact resistance of concrete. Moreover, the simulated penetration test indicates that steel fibers are more effective than propylene fibers, type of coarse aggregate has negligible effect, and steel fiber volume fraction has a more significant influence than fiber shape for reinforced concrete test panels. Finally, as expectable, surface properties of tested concrete panels have a significant effect on impact and penetration resistance.

  8. Bystander Host Cell Killing Effects of Clostridium perfringens Enterotoxin

    Directory of Open Access Journals (Sweden)

    Archana Shrestha

    2016-12-01

    Full Text Available Clostridium perfringens enterotoxin (CPE binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease.

  9. Penetration equations

    Energy Technology Data Exchange (ETDEWEB)

    Young, C.W. [Applied Research Associates, Inc., Albuquerque, NM (United States)

    1997-10-01

    In 1967, Sandia National Laboratories published empirical equations to predict penetration into natural earth materials and concrete. Since that time there have been several small changes to the basic equations, and several more additions to the overall technique for predicting penetration into soil, rock, concrete, ice, and frozen soil. The most recent update to the equations was published in 1988, and since that time there have been changes in the equations to better match the expanding data base, especially in concrete penetration. This is a standalone report documenting the latest version of the Young/Sandia penetration equations and related analytical techniques to predict penetration into natural earth materials and concrete. 11 refs., 6 tabs.

  10. The Effect of Tax Havens on Host Country Welfare

    OpenAIRE

    Thomas A. Gresik; Schindler, Dirk; Schjelderup, Guttorm

    2015-01-01

    Multinational corporations can shift income into low-tax countries through transfer pricing and debt financing. While most developed countries use thin capitalization rules to limit the extent to which a subsidiary can be financed with internal debt, a number of developing countries do not. In this paper, we analyze the effect on FDI and host country welfare of thin capitalization rules when multinationals can also shift income via transfer prices. We show that while permissive...

  11. The Effect of Tax Havens on Host Country Welfare

    OpenAIRE

    Thomas A. Gresik; Schindler, Dirk; Schjelderup, Guttorm

    2015-01-01

    Multinational corporations can shift income into low-tax countries through transfer pricing and debt financing. While most developed countries use thin capitalization rules to limit the extent to which a subsidiary can be financed with internal debt, a number of developing countries do not. In this paper, we analyze the effect on FDI and host country welfare of thin capitalization rules when multinationals can also shift income via transfer prices. We show that while permissive thin capitaliz...

  12. Effects of the preparation technique and type of material on the penetrability of sealants.

    Science.gov (United States)

    Cho, John S; Covey, David; Abdelmegid, Faika; Salama, Fouad

    2015-01-01

    The purpose of this in vitro study was to compare the penetration of 2 resin-based and 2 glass ionomer sealants into fissures after either conventional or mechanical preparation. All the materials placed in the conventionally prepared and mechanically prepared fissures penetrated the fissures beyond the standard (0.5-mm) reference line used in this study. For 1 glass ionomer sealant, the number of specimens showing complete penetration of sealant was significantly greater (P sealants.

  13. Fly ash effect on hatching, mortality and penetration of root-knot nematode (Meloidogyne incognita in pumpkin roots

    Directory of Open Access Journals (Sweden)

    Gufran Ahmad

    2016-09-01

    Full Text Available An experiment was conducted to observe the effect of fly ash on hatching, mortality and penetration of root-knot nematode (Meloidogyne incognita in pumpkin roots. For hatching experiment different fly ash-extract concentrations (5, 10, 20, 30, 40, and 50% were prepared. Hatching was significantly reduced in all concentrations, maximum being at 50% concentration. The mortality (% of juveniles was observed in 1, 2, 3, 4, 5, 6 and 7th days with different levels (5, 10, 20, 30, 40 and 50 % of fly ash-extract. All the levels were found harmful to juveniles. As the level was increased, the killing percentage of juveniles was also increased. Highest mortality was observed in 7th day with 50% level.For the penetration experiment, fly ash was mixed with soil to prepare different concentrations (5, 10, 20, 30, 40, and 50%. Seeds of pumpkin were grown in coffee cups filled with different mixtures. At two leaf stage, seedlings were inoculated with 2000 larvae. The penetrated larvae in roots were observed after 1, 2, 3, 4, 5, 6 and 7 days. Root penetration was found inversely proportional to concentration. Significant results in the suppression of nematode penetration were noted up to 40% concentration. However, none of the juveniles was penetrated at 50% concentration.International Journal of Environment Vol.5(3 2016, pp.66-73

  14. [The effect of epidermal growth factor on keratocytes during healing of corneal penetrating incision].

    Science.gov (United States)

    Usuki, Y; Katakami, C; Yamamoto, M

    1995-11-01

    We investigated the effect of epidermal growth factor (EGF) on keratocytes during corneal wound healing focusing on cell proliferation. A penetrating linear incision was made in the center of rabbit corneas. The corneas were then treated with eye drops of recombinant human EGF (10 micrograms/ml) or physiological saline (control) four times a day. After 1, 2, 3, and 7 days, the corneas were excised, labeled with 3H-thymidine (10 microCi/ml) at 37 degrees C for 4 hours and subjected to autoradiography. The results demonstrated increased number of keratocytes incorporating 3H-thymidine on the 1st, 2nd, 3rd and 7th days of healing and accelerated stromal wound healing in corneas treated with EGF compared with the controls. Thus, EGF stimulates of proliferation keratocyte and promotes corneal stromal wound healing.

  15. Effect of olive oil on transdermal penetration of flurbiprofen from topical gel as enhancer.

    Science.gov (United States)

    Hussain, Abid; Khan, Gul Majid; Jan, Syed Umer; Shah, Shefaatullah; Shah, Kifayatullah; Akhlaq, Muhammad; Rahim, Nouman; Nawaz, Asif; Wahab, Abdul

    2012-04-01

    The present study was conducted to formulate and evaluate flurbiprofen transdermal gel. A standard calibration curve was constructed to obtain a regression line equation to be used for finding out the concentration of drug in samples. Olive oil was used as penetration enhancer and was added in different concentrations to some selected formulations to see its enhancement effect on in vitro drug release profiles. The prepared gels were evaluated for several physico-chemical parameters to justify their suitability for topical use. The in vitro drug release studies were carried out by using Franz cell diffusion apparatus across both synthetic membrane and excised albino rabbit skin. In order to investigate the drug release mechanism a kinetic approach was made by employing Korsmeyer kinetic model to the in vitro drug release profiles of flurbiprofen. The flurbiprofen topical gels were successfully prepared and could be beneficial for topical use.

  16. Effects of basic human values on host community acculturation orientations.

    Science.gov (United States)

    Sapienza, Irene; Hichy, Zira; Guarnera, Maria; Nuovo, Santo Di

    2010-08-01

    Although literature provides evidence for the relationship between values and acculturation, the relationship between host community acculturation orientations has not yet been investigated. In this study we tested the effects of four high-order values (openness to change, self-transcendence, conservation, and self-enhancement, devised according to Schwartz's model) on host community acculturation orientations towards immigrants (devised according the interactive acculturation model) in the public domain of employment and the private domain of endogamy/exogamy. Participants were 264 Italian University students, who completed a questionnaire containing the Portrait Values Questionnaire, a measure of personal values, and the Host Community Acculturation Scale, aimed at measuring Italian acculturation strategies towards three groups of immigrants: Immigrants (the general category), Chinese (the valued immigrant group), and Albanians (the devalued immigrant group). Results showed that personal values are related to the adoption of acculturation orientations: In particular, the values that mostly impacted on acculturation orientations were self-transcendence and conservation. Values concerning self-transcendence encourage the adoption of integrationism, integrationism-transformation, and individualism and reduce the adoption of assimilationism, segregationism, and exclusionism. Values concerning conservation encourage the adoption of assimilation, segregation and exclusion orientations and reduce the adoption of both types of integrationism and individualism. Minor effects were found regarding self-enhancement and openness to change.

  17. [Effect of terpene penetration enhancer and its mechanisms on membrane fluidity and potential of HaCaT keratinocytes].

    Science.gov (United States)

    Lan, Yi; Wang, Jing-yan; Liu, Yan; Ru, Qing-guo; Wang, Yi-fei; Yu, Jing-xin; Wu, Qing

    2015-02-01

    The aim of this paper was to investigate the effect of terpene penetration enhancers on membrane fluidity and membrane potential using HaCaT keratinocytes, and study the potential mechanisms of these terpene compounds using as natural transdermal penetration enhancer. Six terpene compounds, namely menthol, limonene, 1,8-cineole, menthone, terpinen-4-ol and pulegone, were chosen in this study on account of their good penetration-enhancement activities. The cytotoxicity of these terpene compounds was measured using an MTT assay. The fluorescence recovery after photobleaching (FRAP) technique was employed to measure the change of membrane fluidity of HaCaT cells. The flow cytometer was used to study the alteration of membrane fluidity of HaCaT cells, and investigate the effect of terpene compounds on intracellular Ca2+. It was found that 6 terpene compounds possessed low cytotoxicity in comparison to the well-established and standard penetration enhancer azone. Those terpene compounds could significantly enhance HaCaT cells membrane fluidity and decrease HaCaT cells membrane potentials. Meanwhile, after treated with various terpene compounds, the Ca2(+)-ATPase activity and intracellular Ca2+ of HaCaT cells was decreased significantly. Terpene penetration enhancers perhaps changed the membrane fluidity and potentials of HaCaT cells by altering the Ca2+ balance of the cell inside and outside, resulting in the low skin permeability to increase the drug transdermal absorption.

  18. Novel secretory protein Ss-Caf1 of the plant-pathogenic fungus Sclerotinia sclerotiorum is required for host penetration and normal sclerotial development.

    Science.gov (United States)

    Xiao, Xueqiong; Xie, Jiatao; Cheng, Jiasen; Li, Guoqing; Yi, Xianhong; Jiang, Daohong; Fu, Yanping

    2014-01-01

    To decipher the mechanism of pathogenicity in Sclerotinia sclerotiorum, a pathogenicity-defective mutant, Sunf-MT6, was isolated from a T-DNA insertional library. Sunf-MT6 could not form compound appressorium and failed to induce lesions on leaves of rapeseed though it could produce more oxalic acid than the wild-type strain. However, it could enter into host tissues via wounds and cause typical necrotic lesions. Furthermore, Sunf-MT6 produced fewer but larger sclerotia than the wild-type strain Sunf-M. A gene, named Ss-caf1, was disrupted by T-DNA insertion in Sunf-MT6. Gene complementation and knockdown experiments confirmed that the disruption of Ss-caf1 was responsible for the phenotypic changes of Sunf-MT6. Ss-caf1 encodes a secretory protein with a putative Ca(2+)-binding EF-hand motif. High expression levels of Ss-caf1 were observed at an early stage of compound appressorium formation and in immature sclerotia. Expression of Ss-caf1 without signal peptides in Nicotiana benthamiana via Tobacco rattle virus-based vectors elicited cell death. These results suggest that Ss-caf1 plays an important role in compound appressorium formation and sclerotial development of S. sclerotiorum. In addition, Ss-Caf1 has the potential to interact with certain host proteins or unknown substances in host cells, resulting in subsequent host cell death.

  19. The Effects of Geometry on Skin Penetration and Failure of Polymer Microneedles

    Science.gov (United States)

    Gittard, Shaun D; Chen, Bo; Xu, Huadong; Ovsianikov, Aleksandr; Chichkov, Boris N; Monteiro-Riviere, Nancy A; Narayan, Roger J

    2012-01-01

    Microneedles are small-scale devices that may be used for drug delivery and biosensing. In this study, the forces required for mechanical failure, the modes of mechanical failure, as well as the mechanisms for microneedle penetration into porcine skin were examined. Microneedles produced from the acrylate-based polymer e-Shell 200 using an indirect rapid prototyping approach involving two-photon polymerization and poly(dimethylsiloxane) micromolding were found to possess sufficient strength for penetration of porcine skin. The failure forces were an order of magnitude greater than the forces necessary for full insertion into the skin. Bending was the most common form of failure; an increasing aspect ratio and a decreasing tip diameter were associated with lower failure forces. Video captured during skin penetration revealed that microneedle penetration into the skin occurred by means of a series of insertions and not by means of a single insertion event. Images obtained during and after skin penetration confirmed microneedle penetration of skin as well as transdermal delivery of lucifer yellow dye. These findings shed insight into the mechanisms of microneedle penetration and failure, facilitating design improvements for polymer microneedles. PMID:23543070

  20. The Effect of Arrow Mass and Shape on Penetration into a Target

    Science.gov (United States)

    Shyam, S.; Gurram, A.; Madireddy, S.

    2016-12-01

    We conducted an archery experiment in order to quantify how aerodynamic design impacted the depth of arrow impact. Research shows that the smaller the surface area of an object, the more easily it travels through the air and the deeper it penetrates a target (Benson 2014). Momentum also affects how far and fast the arrow will go and therefore, how deep it will penetrate into the target. Therefore, a combination of an arrow with greater momentum and better aerodynamics will help the arrow fly faster and penetrate the target deeper. Mass, velocity, momentum, acceleration, force, and drag are the factors that acted on our experiment and produced its results. We hypothesized that the arrow with a thin shaft and pointed arrowhead would penetrate deepest, as opposed to both arrows with no arrowheads or arrows with thick shafts and blunt arrowheads. We tested our hypothesis by having a well-trained archer shoot different types of arrows into a target. We used arrows with shaft lengths of 7 cm and 5.3 cm, coupled with either pointed, blunt, or no arrowhead. We measured the time to target and arrow penetration (in cm) to see which style reached the target the fastest and penetrated the deepest. The results demonstrated that arrows with thin shafts and pointed arrowheads penetrated our target the deepest, followed by arrows with thick shafts and blunt arrowheads. Arrows with thin shafts and blunt arrowheads came after, and arrows with thick shafts and pointed arrowheads came last in depth of penetration. The arrows with no arrowheads either barely penetrated the target, or bounced back. We were able to conclude that the thinner the shaft and the more pointed the arrowhead, the better the arrow cuts the air. This is because, according to the principles of aerodynamics, it creates less drag since the surface area is smaller. However, mass also plays an important role in force through momentum, which also significantly affected our results.

  1. The effect of fissure morphology and eruption time on penetration and adaptation of pit and fissure sealants: An SEM study

    Directory of Open Access Journals (Sweden)

    Grewal N

    2008-06-01

    Full Text Available This study was designed to examine the effect of fissure morphology on penetration and adaptation of fissure sealants and their relationship with the eruption time of tooth. Materials and Methods: One hundred and fifty extracted molars and premolars were divided into two groups on the basis of their eruption time. The two groups were further divided into five subgroups on the basis of fissure morphology. An scanning electron microscopic analysis of penetration and adaptation of sealant was done. Observations and Results: V- and U-shaped fissures were found to have the maximum penetration. Penetration was very poor for I- and IK-types of fissures. No significant difference in penetration was found in relation to eruption time. Adaptation of sealant was not affected by any of the factors. Conclusion: Even the well-applied sealant does not necessarily provide complete obturation of pits and fissures, thus necessitating periodical clinical observation to determine the success or potential failure of the sealant treatment.

  2. Effect of penetrating ionising radiation on the mechanical properties of pericardium

    Energy Technology Data Exchange (ETDEWEB)

    Daar, Eman, E-mail: e.daar@surrey.ac.u [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Woods, E. [Royal Free Hampstead NHS Trust, Pond Street, Hampstead, London NW3 2QG (United Kingdom); Keddie, J.L. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Nisbet, A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Royal Surrey County Hospital, Guildford (United Kingdom); Bradley, D.A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2010-07-21

    The pericardium is an anistropic composite material made up of collagen and elastin fibres embedded in an amorphous matrix mainly composed of proteoglycan and hyaluronan. The collagen fibres are arranged in layers, with different directions of alignment in each layer, giving rise to interesting mechanical properties of pericardium, including the ability to undergo large deformation during performance of regular physiological functions. The present study aims to investigate the effect of penetrating photon ionising radiation on bovine pericardium tissue, being part of a study of the effect of cardiac doses received in breast radiotherapy and the possibility that this can give rise to cardiovascular complications. Irradiation doses in the range 5-80 Gy were used. To characterise the various mechanical properties [elastic modulus, stress relaxation, ultimate tensile strength (UTS) and fracture] a uniaxial tensile test method was applied. The preliminary results reflect the wide inter-sample variations that are expected in dealing with tissues, with only a weak indication of increase in the UTS of the pericardium tissue with increase in radiation dose. Such an effect has also been observed by others, with reduction in UTS at doses of 80 Gy.

  3. The effect of topical autologous serum on graft re-epithelialization after penetrating keratoplasty.

    Science.gov (United States)

    Chen, Yan-Ming; Hu, Fung-Rong; Huang, Jehn-Yu; Shen, Elizabeth P; Tsai, Tzu-Yun; Chen, Wei-Li

    2010-09-01

    To analyze factors influencing corneal graft re-epithelialization after penetrating keratoplasty (PK) and evaluate the effect of topical autologous serum in promoting graft re-epithelialization. Prospective interventional study. We analyzed 165 eyes of 165 patients who underwent PK between January 1, 2005 and December 31, 2007. Patients were divided into 2 groups according to routine use or non-use of postoperative 20% topical autologous serum. Postoperative slit-lamp examination after fluorescein staining was performed, and graft re-epithelialization time was recorded. Recipient/donor characteristics, surgical variables, and topical use of autologous serum were analyzed for their effects on post-PK graft re-epithelialization. Statistical analysis was performed by univariate and multivariate regression analysis using the ordinal logistic fit model to assess the potential risk factors influencing graft re-epithelialization after PK. In univariate analysis, diabetes mellitus (DM), longer death-to-storage time and death-to-surgery time of the donor, and larger recipient size significantly delayed graft re-epithelialization (P healing effect of autologous serum is particularly significant in diabetic recipients and larger grafts. Several factors may influence graft re-epithelialization after PK. Graft re-epithelialization time was longer in diabetic recipients and larger grafts. Use of autologous serum may be a beneficial strategy in these patients with potentially delayed epithelial healing. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  4. Effect of penetrating ionising radiation on the mechanical properties of pericardium

    Science.gov (United States)

    Daar, Eman; Woods, E.; Keddie, J. L.; Nisbet, A.; Bradley, D. A.

    2010-07-01

    The pericardium is an anistropic composite material made up of collagen and elastin fibres embedded in an amorphous matrix mainly composed of proteoglycan and hyaluronan. The collagen fibres are arranged in layers, with different directions of alignment in each layer, giving rise to interesting mechanical properties of pericardium, including the ability to undergo large deformation during performance of regular physiological functions. The present study aims to investigate the effect of penetrating photon ionising radiation on bovine pericardium tissue, being part of a study of the effect of cardiac doses received in breast radiotherapy and the possibility that this can give rise to cardiovascular complications. Irradiation doses in the range 5-80 Gy were used. To characterise the various mechanical properties [elastic modulus, stress relaxation, ultimate tensile strength (UTS) and fracture] a uniaxial tensile test method was applied. The preliminary results reflect the wide inter-sample variations that are expected in dealing with tissues, with only a weak indication of increase in the UTS of the pericardium tissue with increase in radiation dose. Such an effect has also been observed by others, with reduction in UTS at doses of 80 Gy.

  5. Effect of welding parameters of the Nd:YAG laser on the penetration depth of cobalt chromium alloys.

    Science.gov (United States)

    Vlachogianni, V; Clark, R K F; Juszczyk, A S; Radford, D R

    2012-03-01

    The aim of the investigation was to study the effect of the laser welding parameters of energy and spot diameter on the penetration depth of the weld of cast Co-Cr alloy when a single weld was performed. Within the limitations of the study as voltage increased and the spot diameter decreased, penetration depth increased. However, SEM investigation showed more defects in the welded area under these circumstances. The clinical significance is that during selection of the welding parameters the thickness of the components to be welded should be considered to achieve an extended welded area without the induction of micro-structural defects.

  6. Effects of Simulated Microgravity on a Host-Pathogen System

    Science.gov (United States)

    Gilbert, Rachel; Lo, Rachel; Bhattacharya, Sharmila

    2017-01-01

    While it has been shown that decades of astronauts and cosmonauts can suffer from illnesses both during and after spaceflight, the underlying causes are still poorly understood, due in part to the fact that there are so many variables to consider when investigating the human immune system in a complex environment. Invertebrates have become popular models for studying human disease because they are cheap, highly amenable to experimental manipulation, and have innate immune systems with a high genetic similarity to humans. Fruit flies (Drosophila melanogaster) have been shown to experience a dramatic shift in immune gene expression following spaceflight, but are still able to fight off infections when exposed to bacteria. However, the common bacterial pathogen Serratia marcescens was shown to become more lethal to fruit flies after being cultured in space, suggesting that not only do we need to consider host changes in susceptibility, but also changes in the pathogen itself after spaceflight conditions. Being able to simulate spaceflight conditions in a controlled environment on the ground gives us the ability to not only evaluate the effects of microgravity on the host immune system, but also how the microorganisms that cause immune disorders are being affected by these drastic environmental shifts. In this study, I use a ground-based simulated microgravity environment to examine the genetic changes associated with increased S. marcescens virulence in order to understand how microgravity is affecting this pathogen, as well as how these genetic changes influence and interact with the host immune system. This study will provide us with more directed approaches to studying the effects of spaceflight on human beings, with the ultimate goal of being able to counteract immune dysfunction in future space exploration.

  7. Penetration effect of prostaglandin E2 gel on oral mucosa of rats

    Directory of Open Access Journals (Sweden)

    Rafinus Arifin

    2012-09-01

    Full Text Available Background: Several researches reported that Prostaglandin E2 (PGE2 injection on buccal mucosa combined with orthodontic pressure can faster tooth movement but has disadvantages such as high alveolar bone and root resorption furthermore pain from injection needle. PGE2 gel was made to better replace the lacks of injectable PGE2. Purpose: This research was aimed to prove that PGE 2 gel can penetrate rat’s oral mucosa effecting the appearance of PMN cells. Methods: This research was an in vivo laboratory experiment using 36 Sprague Dawley rats which were divided into 3 groups: normal group, topical PGE2 gel group after 1, 2, 4, 8 hours (4 subgroups, and topical gel without PGE2 group after 1, 2, 4, 8 hours (4 subgroups. Each group consists of 4 rats, therefore the total sample for all research groups were 36 rats. Gel with 25 µg/mL of PGE2 and gel without PGE2 were applied on oral mucosa for 2 minutes. Then, the rats were sacrificed after 1 hour, 2 hours, 4 hours, and 8 hours application. After that, the samples were prepared for histological examination with Hematoxyllin and Eosin. The picture were taken with OptiLab View and PMN cells amount were counted with light microscope, set 400 times of magnification. Results: Penetration effect of PGE2 gel on rat’s oral mucosa result in PMN inflammation cells distribution. One-way ANOVA showed no significant difference on PMN cells count in rats’ lower jaws between groups of normal and gel without PGE2. There was significant difference between groups of PGE2 gel and gel without PGE2 (p=0,001. PGE2 gel application showed PGE2 as inflammatory media, even though administered topically. Conclusion: PGE2 gel can penetrate rat’s oral mucosa, effecting PMN cells 1, 2, 4 and 8 hours after application of PGE2 gel.Latar belakang: Beberapa penelitian melaporkan bahwa injeksi (Prostaglandin E2 PGE2pada mukosa bukal yang dikombinasikan dengan tekanan ortodonti dapat mempercepat pergerakan gigi, tapi

  8. Evaluation of geometrical effects of microneedles on skin penetration by CT scan and finite element analysis.

    Science.gov (United States)

    Loizidou, Eriketi Z; Inoue, Nicholas T; Ashton-Barnett, Johnny; Barrow, David A; Allender, Chris J

    2016-10-01

    Computerized tomography scan (CT scan) imaging and finite element analysis were employed to investigate how the geometric composition of microneedles affects their mechanical strength and penetration characteristics. Simulations of microneedle arrays, comprising triangular, square and hexagonal microneedle base, revealed a linear dependence of the mechanical strength to the number of vertices in the polygon base. A laser-enabled, micromoulding technique was then used to fabricate 3×3 microneedle arrays, each individual microneedle having triangular, square or hexagonal base geometries. Their penetration characteristics into ex-vivo porcine skin, were investigated for the first time by CT scan imaging. This revealed greater penetration depths for the triangular and square-based microneedles, demonstrating CT scan as a powerful and reliable technique for studying microneedle skin penetration. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. A comparative study on the transdermal penetration effect of gaseous and aqueous plasma reactive species

    Science.gov (United States)

    Liu, Xin; Gan, Lu; Ma, Mingyu; Zhang, Song; Liu, Jingjing; Chen, Hongxiang; Liu, Dawei; Lu, Xinpei

    2018-02-01

    To improve the depth of plasma active species in the skin, it is very important to develop skin disease treatment using plasma. In this article, an air plasma source was used to work directly with the skin of a mouse. A tortuous pathway, hair follicles, electroporation and a microneedle do not aid the transdermal delivery of gaseous plasma active species, therefore these gaseous plasma active species cannot penetrate mouse skin with a thickness of ~0.75 mm. The plasma activated water (PAW) produced by the air plasma source was used to study the transdermal penetration of the aqueous plasma activated species. This aqueous plasma activated species can penetrate the skin through hair follicles, intercellular and transcellular routes. The pH of the PAW did not affect the penetration efficiency of the aqueous plasma active species.

  10. Effective Moisture Penetration Depth Model for Residential Buildings: Sensitivity Analysis and Guidance on Model Inputs

    Energy Technology Data Exchange (ETDEWEB)

    Woods, Jason D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Winkler, Jonathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-01-31

    Moisture buffering of building materials has a significant impact on the building's indoor humidity, and building energy simulations need to model this buffering to accurately predict the humidity. Researchers requiring a simple moisture-buffering approach typically rely on the effective-capacitance model, which has been shown to be a poor predictor of actual indoor humidity. This paper describes an alternative two-layer effective moisture penetration depth (EMPD) model and its inputs. While this model has been used previously, there is a need to understand the sensitivity of this model to uncertain inputs. In this paper, we use the moisture-adsorbent materials exposed to the interior air: drywall, wood, and carpet. We use a global sensitivity analysis to determine which inputs are most influential and how the model's prediction capability degrades due to uncertainty in these inputs. We then compare the model's humidity prediction with measured data from five houses, which shows that this model, and a set of simple inputs, can give reasonable prediction of the indoor humidity.

  11. Effects of various penetration enhancers on percutaneous absorption of piroxicam from emulgels.

    Science.gov (United States)

    Shokri, J; Azarmi, Sh; Fasihi, Z; Hallaj-Nezhadi, S; Nokhodchi, A; Javadzadeh, Y

    2012-10-01

    A suitable emulgel formulation of piroxicam was prepared and its percutaneous permeation was investigated using Wistar rat skin and diffusion cell technique. The concentrations of the drug in receptor phase of diffusion cells were measured using HPLC method. The effect of three types of penetration enhancers (Myrj 52, cineol and Transcutol P) with different concentrations on transdermal permeation of the drug was also evaluated. Flux, Kp and enhancement ratios (ERs) of piroxicam in the presence of enhancers was measured and compared with emulgel base alone and simple commercial gel. The results showed a significant enhancement in the flux from emulgel base compared to hydroalcoholic gel formulation (9.91 folds over simple gel). The highest enhancement ratio (ER=3.11) was observed for Myrj 52 at the concentration of 0.25%. Higher concentrations of Myrj 52did not show any enhancement in the drug flux due to micelle formation and solubilization of the drug by micelles. The increase in solubility, in turn, increases the saturated concentration and reduces the thermodynamic activity of the drug. Transcutol(®) P with concentrations higher than 0.25% w/w showed burst transportation of the drug through the skin. All concentrations of cineol and Transcutol did not show any enhancing effects over emulgel base alone (ER <1).

  12. Skin penetration and antioxidant effect of cosmeto-textiles with gallic acid.

    Science.gov (United States)

    Alonso, C; Martí, M; Barba, C; Lis, M; Rubio, L; Coderch, L

    2016-03-01

    In this work, the antioxidant gallic acid (GA) has been encapsulated in microspheres prepared with poly-ε-caprolactone (PCL) and incorporated into polyamide (PA) obtaining the cosmeto-textile. The topical application of the cosmeto-textile provides a reservoir effect in the skin delivery of GA. The close contact of the cosmeto-textile, containing microsphere-encapsulated GA (ME-GA), with the skin and their corresponding occlusion, may be the main reasons that explain the crossing of active principle (GA) through the skin barrier, located in the stratum corneum, and its penetration into the different compartments of the skin, epidermis and dermis. An ex vivo assessment was performed to evaluate the antioxidant effect of the ME-GA on the stratum corneum (SC) using the thiobarbituric acid-reactive species (TBARS) test. The test is based on a non-invasive ex vivo methodology that evaluates lipid peroxides formed in the outermost layers of the SC from human volunteers after UV radiation to determine the effectiveness of an antioxidant. In this case, a ME-GA cosmeto-textile or ME-GA formulation were applied to the skin in vivo and lipid peroxidation (LPO) in the horny layer were determined after UV irradiation. This methodology may be used as a quality control tool to determine ex vivo the percentage of LPO inhibition on human SC for a variety of antioxidants that are topically applied, in this case GA. Results show that LPO formation was inhibited in human SC when GA was applied directly or embedded in the cosmeto-textile, demonstrating the effectiveness of both applications. The percentage of LPO inhibition obtained after both topical applications was approximately 10% for the cosmeto-textile and 41% for the direct application of microspheres containing GA. This methodology could be used to determine the effectiveness of topically applied antioxidants encapsulated in cosmeto-textiles on human SC. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. In vitro evaluation of cutaneous penetration of acyclovir from semisolid commercial formulations and relation with its effective antiviral concentration

    Directory of Open Access Journals (Sweden)

    Rafaela Martins Sponchiado

    Full Text Available ABSTRACT The evaluation of drug permeation/penetration of semisolid formulations into animal skin can be useful to supplement the pharmaceutical equivalence. This paper describes the in vitro assessment of acyclovir (ACV into porcine skin from commercial formulations with etermination of drug concentration in different layers of cutaneous tissue to correlate with effective antiviral concentration in order to improve the equivalence decision. Studies were conducted using Franz cells and porcine skin. Selected pharmaceutical creams containing ACV had identical (reference and generic and different (similar excipients. A software program was employed for the simulation of antiviral effectiveness in the skin. Regarding ACV skin penetration, the first batch of the generic product showed a significant difference from reference and similar products, while in the second batch all products demonstrated equivalent drug penetration in the skin. Simulation studies suggest that formulations analysed exhibit a pharmacological effect even when in contact with Herpes simplex strains of high IC50 (inhibitory concentration required to reduce viral replication by 50%. According to results, it can be assumed that the in vitro cutaneous permeation/penetration study does not supply sensitivity information regarding small alterations of ACV semisolid formulations due to the variability inherent to the method, although it can be relevant to pharmaceutical equivalence studies in the development of semisolid products.

  14. Compared performance of penetrometers and effect of soil water content on penetration resistance measurements

    Directory of Open Access Journals (Sweden)

    Edison Aparecido Mome Filho

    2014-06-01

    Full Text Available Modern agriculture techniques have a great impact on crops and soil quality, especially by the increased machinery traffic and weight. Several devices have been developed for determining soil properties in the field, aimed at managing compacted areas. Penetrometry is a widely used technique; however, there are several types of penetrometers, which have different action modes that can affect the soil resistance measurement. The objective of this study was to compare the functionality of two penetrometry methods (manual and automated mode in the field identification of compacted, highly mechanized sugarcane areas, considering the influence of soil water volumetric content (θ on soil penetration resistance (PR. Three sugarcane fields on a Rhodic Eutrudrox were chosen, under a sequence of harvest systems: one manual harvest (1ManH, one mechanized harvest (1MH and three mechanized harvests (3MH. The different degrees of mechanization were associated to cumulative compaction processes. An electronic penetrometer was used on PR measurements, so that the rod was introduced into the soil by hand (Manual and by an electromechanical motor (Auto. The θ was measured in the field with a soil moisture sensor. Results showed an effect of θ on PR measurements and that regression models must be used to correct data before comparing harvesting systems. The rod introduction modes resulted in different mean PR values, where the "Manual" overestimated PR compared to the "Auto" mode at low θ.

  15. Effect of Penetration Enhancer Containing Vesicles on the Percutaneous Delivery of Quercetin through New Born Pig Skin

    Directory of Open Access Journals (Sweden)

    Maria Manconi

    2011-08-01

    Full Text Available Quercetin (3,3′,4′,5,7-pentahydroxyflavone exerts multiple pharmacological effects: anti-oxidant activity, induction of apoptosis, modulation of cell cycle, anti-mutagenesis, and anti-inflammatory effect. In topical formulations quercetin inhibits oxidative skin damage and the inflammatory processes induced by solar UV radiation. In this work, quercetin (2 mg/mL was loaded in vesicular Penetration Enhancer containing Vesicles (PEVs, prepared using a mixture of lipids (Phospholipon® 50, P50 and one of four selected hydrophilic penetration enhancers: Transcutol® P, propylene glycol, polyethylene glycol 400, and Labrasol® at the same concentration (40% of water phase. Photon Correlation Spectroscopy results showed a mean diameter of drug loaded vesicles in the range 80–220 nm. All formulations showed a negative surface charge and incorporation efficiency in the range 48–75%. Transmission Electron Microscopy confirmed that size and morphology varied as a function of the used penetration enhancer. The influence of PEVs on ex vivo quercetin (transdermal delivery was evaluated using Franz-type diffusion cells, new born pig skin and Confocal Laser Scanning Microscopy. Results showed that drug delivery is affected by the penetration enhancer used in the PEVs' formulation.

  16. The effect of dexamethasone/cell-penetrating peptide nanoparticles on gene delivery for inner ear therapy.

    Science.gov (United States)

    Yoon, Ji Young; Yang, Keum-Jin; Park, Shi-Nae; Kim, Dong-Kee; Kim, Jong-Duk

    Dexamethasone (Dex)-loaded PHEA-g-C18-Arg8 (PCA) nanoparticles (PCA/Dex) were developed for the delivery of genes to determine the synergistic effect of Dex on gene expression. The cationic PCA nanoparticles were self-assembled to create cationic micelles containing an octadecylamine (C18) core with Dex and an arginine 8 (Arg8) peptide shell for electrostatic complexation with nucleic acids (connexin 26 [Cx26] siRNA, green fluorescent protein [GFP] DNA or brain-derived neurotrophic factor [BDNF] pDNA). The PCA/Dex nanoparticles conjugated with Arg8, a cell-penetrating peptide that enhances permeability through a round window membrane in the inner ear for gene delivery, exhibited high uptake efficiency in HEI-OC1 cells. This potential carrier co-delivering Dex and the gene into inner ear cells has a diameter of 120-140 nm and a zeta potential of 20-25 mV. Different types of genes were complexed with the Dex-loaded PCA nanoparticle (PCA/Dex/gene) for gene expression to induce additional anti-inflammatory effects. PCA/Dex showed mildly increased expression of GFP and lower mRNA expression of inflammatory cytokines (IL1b, IL12, and INFr) than did Dex-free PCA nanoparticles and Lipofectamine(®) reagent in HEI-OC1 cells. In addition, after loading Cx26 siRNA onto the surface of PCA/Dex, Cx26 gene expression was downregulated according to real-time polymerase chain reaction for 24 h, compared with that using Lipofectamine reagent. After loading BDNF DNA into PCA/Dex, increased expression of BDNF was observed for 30 h, and its signaling pathway resulted in an increase in phosphorylation of Akt, observed by Western blotting. Thus, Dex within PCA/Dex/gene nanoparticles created an anti-inflammatory effect and enhanced gene expression.

  17. Conjugation to the cell-penetrating peptide TAT potentiates the photodynamic effect of carboxytetramethylrhodamine.

    Directory of Open Access Journals (Sweden)

    Divyamani Srinivasan

    2011-03-01

    Full Text Available Cell-penetrating peptides (CPPs can transport macromolecular cargos into live cells. However, the cellular delivery efficiency of these reagents is often suboptimal because CPP-cargo conjugates typically remain trapped inside endosomes. Interestingly, irradiation of fluorescently labeled CPPs with light increases the release of the peptide and its cargos into the cytosol. However, the mechanism of this phenomenon is not clear. Here we investigate the molecular basis of the photo-induced endosomolytic activity of the prototypical CPPs TAT labeled to the fluorophore 5(6-carboxytetramethylrhodamine (TMR.We report that TMR-TAT acts as a photosensitizer that can destroy membranes. TMR-TAT escapes from endosomes after exposure to moderate light doses. However, this is also accompanied by loss of plasma membrane integrity, membrane blebbing, and cell-death. In addition, the peptide causes the destruction of cells when applied extracellularly and also triggers the photohemolysis of red blood cells. These photolytic and photocytotoxic effects were inhibited by hydrophobic singlet oxygen quenchers but not by hydrophilic quenchers.Together, these results suggest that TAT can convert an innocuous fluorophore such as TMR into a potent photolytic agent. This effect involves the targeting of the fluorophore to cellular membranes and the production of singlet oxygen within the hydrophobic environment of the membranes. Our findings may be relevant for the design of reagents with photo-induced endosomolytic activity. The photocytotoxicity exhibited by TMR-TAT also suggests that CPP-chromophore conjugates could aid the development of novel Photodynamic Therapy agents.

  18. Investigation of effects of terpene skin penetration enhancers on stability and biological activity of lysozyme.

    Science.gov (United States)

    Varman, Rahul M; Singh, Somnath

    2012-12-01

    The transport of proteins through skin can be facilitated potentially by using terpenes as chemical enhancers. However, we do not know about the effects of these enhancers on the stability and biological activity of proteins which is crucial for the development of safe and efficient formulations. Therefore, this project investigated the effects of terpene-based skin penetration enhancers which are reported as nontoxic to the skin (e.g., limonene, p-cymene, geraniol, farnesol, eugenol, menthol, terpineol, carveol, carvone, fenchone, and verbenone), on the conformational stability and biological activity of a model protein lysozyme. Terpene (5% v/v) was added to lysozyme solution and kept for 24 h (the time normally a transdermal patch remains) for investigating conformational stability profiles and biological activity. Fourier transform infrared spectrophotometer was used to analyze different secondary structures, e.g., α-helix, β-sheet, β-turn, and random coil. Conformational changes were also monitored by differential scanning calorimeter by determining midpoint transition temperature (Tm) and calorimetric enthalpy (ΔH). Biological activity of lysozyme was determined by measuring decrease in A (450) when it was added to a suspension of Micrococcus lysodeikticus. The results of this study indicate that terpenes 9, 10, and 11 (carvone, L-fenchone, and L-verbenone) decreased conformational stability and biological activity of lysozyme significantly (p terpenes used in this study. It is concluded that smaller terpenes containing ketones with low lipophilicity (log K (ow) ∼2.00) would be optimal for preserving conformational stability and biological activity of lysozyme in a transdermal formulation containing terpene as permeation enhancer.

  19. Effect of Different Skin Penetration Promoters in Halobetasol Propionate Permeation and Retention in Human Skin

    Directory of Open Access Journals (Sweden)

    Paulina Carvajal-Vidal

    2017-11-01

    Full Text Available Halobetasol propionate (HB is a potent synthetic corticosteroid used against inflammatory skin diseases, such as dermatitis, eczema, and psoriasis, among others. The aim of this study is to define how the presence of different skin penetration enhancers (nonane, menthone, limonene, azone, carene, decanol, linoleic acid and cetiol affects the penetration and retention in skin of HB. To determine drug penetration through skin, 5% of each promoter was used in an ex vivo system with human skin on Franz cells. The results showed that the highest permeation occurs in the presence of menthone, followed by nonane. Permeation parameters were determined. The in vivo test was assessed, and the formulation containing HB-menthone presented better anti-inflammatory efficacy. These results are useful to generate a specific treatment according to each patient’s needs, and the inflammatory characteristics of the disease.

  20. Effect of Penetration Enhancers on the Percutaneous Delivery of Pain Management Actives.

    Science.gov (United States)

    Trimble, John; Light, Bob

    2016-01-01

    Transdermal compositions for pain management are comprised of nonsteroidal anti-inflammatory drugs, opioid drugs, and adjuvant drugs acting on: voltage-gated channels, gamma-aminobutyric acid receptors, acute musculoskeletal pain, and as an antidepressant. In this work, baclofen, bupivacaine, cyclobenzaprine, diclofenac, gabapentin, ibuprofen, ketamine, and pentoxifylline were loaded in transdermal compositions, prepared using a mixture of lipids (isopropyl palmitate and mineral oil) and one of two selected penetration enhancer mixtures: alkyl dimethicone, phenyl trimethicone, and polyoxyethylene sorbitan monostearate; and cetostearyl polyoxyethylene ether and ethylene oxide/propylene oxide copolymer. The influence of penetration enhancers on transdermal delivery was evaluated using Franz-type diffusion cells and Normal Human 3D Model of Epidermal Tissue. Results showed that drug delivery is affected by the penetration enhancer used in the transdermal composition. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

  1. Effective depth-of-penetration range due to hardness variation for different lots of nominally identical target material

    Directory of Open Access Journals (Sweden)

    Patrick Frueh

    2016-04-01

    A linear regression analysis of penetration vs. hardness shows that a target hardness increase within the given range of 280–330 BHN may result in a reduction of penetration depth of about 5.8 mm at constant velocity. This is equal to a change of −12% at an impact velocity of 1250 m/s. A multiple linear regression analysis included also the influence of yaw angle and impact velocity. It shows that small yaw angles and slight variations of impact velocities provide a smaller variation of the semi-infinite penetration depths than a variation of target hardness within a typical specification span of 50 BHN. For such a span a change in penetration of approximately −4.8 mm due to hardness variation is found, whereas 1° of yaw angle or −10 m/s of velocity variation gives a change of about −1.0 mm respectively −0.9 mm. For the given example, the overwhelming part of the variation is to be attributed to hardness effects – 4.8 mm out of 5.8 mm (83%. For nominally identical target material the target hardness thus influences the ballistic test results more severely than the typical scatter in impact conditions.

  2. Effects of HMO market penetration on physicians' work effort and satisfaction.

    Science.gov (United States)

    Hadley, J; Mitchell, J M

    1997-01-01

    We investigate whether geographic variations in health maintenance organization (HMO) market penetration are associated with three aspects of physicians' practices: number of hours worked per year, number of patients seen per week, and satisfaction with the current practice. Based on multivariate regression analysis of data for 4,373 patient care physicians (under age forty-five) from a national random sample surveyed in 1991, we estimate that a doubling of the average level of HMO penetration is associated with statistically significant differences of 4 percent fewer annual hours, 13.7 percent fewer patients seen per week, and a 20 percent greater likelihood of not being very satisfied with one's current practice.

  3. Horizontal transmission success of Nosema bombi to its adult bumble bee hosts: effects of dosage, spore source and host age.

    Science.gov (United States)

    Rutrecht, S T; Klee, J; Brown, M J F

    2007-11-01

    Parasite transmission dynamics are fundamental to explaining the evolutionary epidemiology of disease because transmission and virulence are tightly linked. Horizontal transmission of microsporidian parasites, e.g. Nosema bombi, may be influenced by numerous factors, including inoculation dose, host susceptibility and host population heterogeneity. Despite previous studies of N. bombi and its bumble bee hosts, neither the epidemiology nor impact of the parasite are as yet understood. Here we investigate the influence N. bombi spore dosage (1000 to 500,000 spores), spore source (Bombus terrestris and B. lucorum isolates) and host age (2- and 10-day-old bees) have on disease establishment and the presence of patent infections in adult bumble bees. Two-day-old bees were twice as susceptible as their 10-day-old sisters, and a 5-fold increase in dosage from 100,000 to 500,000 spores resulted in a 20-fold increase in the prevalence of patent infections. While intraspecific inoculations were 3 times more likely to result in non-patent infections there was no such effect on the development of patent infections. These results suggest that host-age and dose are likely to play a role in N. bombi's evolutionary epidemiology. The relatively low levels of horizontal transmission success are suggestive of low virulence in this system.

  4. Detrimental effects of host anemone bleaching on anemonefish populations

    Science.gov (United States)

    Saenz-Agudelo, P.; Jones, G. P.; Thorrold, S. R.; Planes, S.

    2011-06-01

    Coral bleaching and related reef degradation have caused significant declines in the abundance of reef-associated fishes. Most attention on the effects of bleaching has focused on corals, but bleaching is also prevalent in other cnidarians, including sea anemones. The consequences of anemone bleaching are unknown, and the demographic effects of bleaching on associated fish recruitment, survival, and reproduction are poorly understood. We examined the effect of habitat degradation including host anemone bleaching on fish abundance, egg production, and recruitment of the panda anemonefish ( Amphiprion polymnus) near Port Moresby, Papua New Guinea. Following a high-temperature anomaly in shallow waters of the region, most shallow anemones to a depth of 6 m (approximately 35% of all the anemones in this area) were severely bleached. Anemone mortality was low but bleached anemones underwent a ~34% reduction in body size. Total numbers of A. polymnus were not affected by bleaching and reduction in shelter area. While egg production of females living in bleached anemones was reduced by ~38% in 2009 compared to 2008, egg production of females on unbleached anemones did not differ significantly between years. Total recruitment in 2009 was much lower than in 2008. However, we found no evidence of recruiting larvae avoiding bleached anemones at settlement suggesting that other factors or different chemical cues were more important in determining recruitment than habitat quality. These results provide the first field evidence of detrimental effects of climate-induced bleaching and habitat degradation on reproduction and recruitment of anemonefish.

  5. [The visual functional therapeutic effects of deep lamellar keratoplasty and penetrating keratoplasty for fungal corneal ulcer].

    Science.gov (United States)

    Lu, Qin-kang; Tong, Qi-hu; Lai, Xiao-ming; Wang, Hui-yun; Zhao, Na

    2011-05-01

    To investigate the visual functional therapeutic effects of deep lamellar keratoplasty (DLK) and penetrating keratoplasty (PK) on perforated fungal keratitis. 64 patients (64 eyes) of fungal corneal ulcer in Ophthalmology Center of Ningbo Yinzhou People Hospital from 2004 to 2009 were retrospected, of which undergo DLK (36 patients, 36 eyes) and PK (28 patients, 28 eyes), and followed up by 12 to 24 months. Check two sets of patients' VA and refraction before operation, and analyze the best-corrected visual acuity (BCVA), corneal refraction changes, corneal endothelium counting and complications, using χ(2) test and t-test. The BCVA after the operation of two sets are both improved, 32 eyes of DLK set were above 0.4, 19 eyes of PK set were above 0.4, of which the DKL set is a bit better than PK set (χ(2) = 4.304, P > 0.05). The astigmatism of DLK set is smaller than the PK set after operation, and there is significant difference (χ(2) = 4.98, P astigmatism of two sets on the average were all no more than 5.00 D. The reject reaction of keratoplasty of DLK is less than PK, there is obviously significant difference (χ(2) = 34.17, P < 0.05). There is less complications of DLK than PK for fungal corneal ulcer. DLK can reduce the occurrence of reject reaction of endothelium type, and the BCVA, refraction of DLK after operation is similar to PK, the incidence rate of surgical operation failure is low.

  6. Effects of penetrating traumatic brain injury on event segmentation and memory.

    Science.gov (United States)

    Zacks, Jeffrey M; Kurby, Christopher A; Landazabal, Claudia S; Krueger, Frank; Grafman, Jordan

    2016-01-01

    Penetrating traumatic brain injury (pTBI) is associated with deficits in cognitive tasks including comprehension and memory, and also with impairments in tasks of daily living. In naturalistic settings, one important component of cognitive task performance is event segmentation, the ability to parse the ongoing stream of behavior into meaningful units. Event segmentation ability is associated with memory performance and with action control, but is not well assessed by standard neuropsychological assessments or laboratory tasks. Here, we measured event segmentation and memory in a sample of 123 male military veterans aged 59-81 who had suffered a traumatic brain injury as young men, and 34 demographically similar controls. Participants watched movies of everyday activities and segmented them to identify fine-grained or coarse-grained events, and then completed tests of recognition memory for pictures from the movies and of memory for the temporal order of actions in the movies. Lesion location and volume were assessed with computed tomography (CT) imaging. Patients with traumatic brain injury were impaired on event segmentation. Those with larger lesions had larger impairments for fine segmentation and also impairments for both memory measures. Further, the degree of memory impairment was statistically mediated by the degree of event segmentation impairment. There was some evidence that lesions to the ventromedial prefrontal cortex (vmPFC) selectively impaired coarse segmentation; however, lesions outside of a priori regions of interest also were associated with impaired segmentation. One possibility is that the effect of vmPFC damage reflects the role of prefrontal event knowledge representations in ongoing comprehension. These results suggest that assessment of naturalistic event comprehension can be a valuable component of cognitive assessment in cases of traumatic brain injury, and that interventions aimed at event segmentation could be clinically helpful

  7. Effects of Penetrating Traumatic Brain Injury on Event Segmentation and Memory

    Science.gov (United States)

    Zacks, Jeffrey M.; Kurby, Christopher A.; Landazabal, Claudia S.; Krueger, Frank; Grafman, Jordan

    2015-01-01

    Penetrating traumatic brain injury is associated with deficits in cognitive tasks including comprehension and memory, and also with impairments in tasks of daily living. In naturalistic settings, one important component of cognitive task performance is event segmentation, the ability to parse the ongoing stream of behavior into meaningful units. Event segmentation ability is associated with memory performance and with action control, but is not well assessed by standard neuropsychological assessments or laboratory tasks. Here, we measured event segmentation and memory in a sample of 123 male military veterans aged 59–81 who had suffered a traumatic brain injury as young men, and 34 demographically similar controls. Participants watched movies of everyday activities and segmented them to identify fine-grained or coarse-grained events, and then completed tests of recognition memory for pictures from the movies and of memory for the temporal order of actions in the movies. Lesion location and volume were assessed with computed tomography imaging. Patients with traumatic brain injury were impaired on event segmentation. Those with larger lesions had larger impairments for fine segmentation and also impairments for both memory measures. Further, the degree of memory impairment was statistically mediated by the degree of event segmentation impairment. There was some evidence that lesions to the ventromedial prefrontal cortex (vmPFC) selectively impaired coarse segmentation; however, lesions outside of a priori regions of interest also were associated with impaired segmentation. One possibility is that the effect of vmPFC damage reflects the role of prefrontal event knowledge representations in ongoing comprehension. These results suggest that assessment of naturalistic event comprehension can be a valuable component of cognitive assessment in cases of traumatic brain injury, and that interventions aimed at event segmentation could be clinically helpful. PMID:26704077

  8. The Effects of Aphid Traits on Parasitoid Host Use and Specialist Advantage.

    Science.gov (United States)

    Gagic, Vesna; Petrović-Obradović, Olivera; Fründ, Jochen; Kavallieratos, Nickolas G; Athanassiou, Christos G; Starý, Petr; Tomanović, Željko

    2016-01-01

    Specialization is a central concept in ecology and one of the fundamental properties of parasitoids. Highly specialized parasitoids tend to be more efficient in host-use compared to generalized parasitoids, presumably owing to the trade-off between host range and host-use efficiency. However, it remains unknown how parasitoid host specificity and host-use depends on host traits related to susceptibility to parasitoid attack. To address this question, we used data from a 13-year survey of interactions among 142 aphid and 75 parasitoid species in nine European countries. We found that only aphid traits related to local resource characteristics seem to influence the trade-off between host-range and efficiency: more specialized parasitoids had an apparent advantage (higher abundance on shared hosts) on aphids with sparse colonies, ant-attendance and without concealment, and this was more evident when host relatedness was included in calculation of parasitoid specificity. More traits influenced average assemblage specialization, which was highest in aphids that are monophagous, monoecious, large, highly mobile (easily drop from a plant), without myrmecophily, habitat specialists, inhabit non-agricultural habitats and have sparse colonies. Differences in aphid wax production did not influence parasitoid host specificity and host-use. Our study is the first step in identifying host traits important for aphid parasitoid host specificity and host-use and improves our understanding of bottom-up effects of aphid traits on aphid-parasitoid food web structure.

  9. HCV tumor promoting effect is dependent on host genetic background.

    Directory of Open Access Journals (Sweden)

    Naama Klopstock

    Full Text Available BACKGROUND: The hepatitis C virus (HCV is one of the major risk factors for the development of hepatocellular carcinoma (HCC. Nevertheless, transgenic mice which express the whole HCV polyprotein (HCV-Tg do not develop HCC. Whereas chronic HCV infection causes inflammation in patients, in HCV-Tg mice, the host immune reaction against viral proteins is lacking. We aimed to test the role of HCV proteins in HCC development on the background of chronic inflammation in vivo. METHODOLOGY/PRINCIPAL FINDINGS: We crossed HCV-Tg mice that do not develop HCC with the Mdr2-knockout (Mdr2-KO mice which develop inflammation-associated HCC, to generate Mdr2-KO/HCV-Tg mice. We studied the effect of the HCV transgene on tumor incidence, hepatocyte mitosis and apoptosis, and investigated the potential contributing factors for the generated phenotype by gene expression and protein analyses. The Mdr2-KO/HCV-Tg females from the N2 generation of this breeding (having 75% of the FVB/N genome and 25% of the C57BL/6 genome produced significantly larger tumors in comparison with Mdr2-KO mice. In parallel, the Mdr2-KO/HCV-Tg females had an enhanced inflammatory gene expression signature. However, in the N7 generation (having 99.2% of the FVB/N genome and 0.8% of the C57BL/6 genome there was no difference in tumor development between Mdr2-KO/HCV-Tg and Mdr2-KO animals of both sexes. The HCV transgene was similarly expressed in the livers of Mdr2-KO/HCV-Tg females of both generations, as revealed by detection of the HCV transcript and the core protein. CONCLUSION: These findings suggest that the HCV transgene accelerated inflammation-associated hepatocarcinogenesis in a host genetic background-dependent manner.

  10. Some observations on the effect of grass-seed penetration On the ...

    African Journals Online (AJOL)

    If sheep other than the smooth coated indigenous types are introduced in these areas, the seeds of H contortus, through hydroscopic action, penetrate the skin and if present in any numbers, may render the carcuse unattractive and cause festering. The dressing out percentage is also lowered, and a carcase with a great ...

  11. Anion effects on the cyclobis(paraquat-p-phenylene) host

    DEFF Research Database (Denmark)

    Andersen, Sissel Stenbæk; Jensen, Morten; Sørensen, Anne

    2012-01-01

    Binding studies between the electron accepting host cyclobis(paraquat-p-phenylene) and a series of electron donors in the presence of differently sized counteranions reveal that both the nature and the concentration of the anion have a large impact on the association strength of the resulting host...

  12. Calcium Lactate addition in Bioconcrete: Effect on Compressive strength and Water penetration

    Directory of Open Access Journals (Sweden)

    Irwan J.M

    2016-01-01

    Full Text Available This paper presents compressive strength and water penetration of bioconcrete with addition of calcium lactate. Bioconcrete has higher engineering concrete properties and durability compared to normal concrete but the natural production of calcium carbonate is limited to the calcium content in cement. Therefore, additional calcium is added as an additional calcium source to study the influence towards compressive strength and water penetration. The bacteria used in this research are Enterococcus faecalis and Bacillus sp. Calcium lactate was added into concrete mix in concentrations of 0.001mol/l, 0.005mol/l and 0.01mol/l of liquid used. The concentration of bacteria added into the mix is by partial replacement of water used in casting, which are 3% for Enterococcus faecalis and 5% for Bacillus sp. Both compressive strength and water penetration test used cubes of 150mm × 150mm × 150mm. The cubes were tested after 28 days. The result of compressive strength for control is 36 MPa while partial replacement of bacteria yields 38.2 MPa for 3% Enterococcus faecalis and 37.0 MPa for 5% Bacillus sp. Calcium lactate with 0.005 mol/L has the best performance with 42.8 MPa for Enterococcus faecalis and 39.6 MPa for Bacillus sp. Whereas for water penetration, the best concentration of calcium lactate which yielded the lowest water penetration is 0.01 mol/l for both Enterococcus faecalis and Bacillus sp which are 8.7 cm and 8 cm respectively. The addition of calcium lactate into bioconcrete is quite promising for improvement of concrete properties and durability.

  13. Effects of acidic precipitation on host-parasite interactions

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, D.S.

    1974-01-01

    During the past decade, the average acidity of rain and snow increased by 1-2 pH units in many parts of Europe and North America. Little is known of the effects of acid rain resulting from dissolution of sulfur dioxide on biological systems. The effects of simulated sulfuric acid rain on four host-pathogen system were studied. Plants were exposed in greenhouse and field to simulated rain of pH 3.2 or pH 6.0 in amounts and intervals common to weather patterns of the eastern United States. Simulated acid rain resulted in: (1) an 86% inhibition in telia production of Cronartium fusiforme on willow oak (Quercus phellos); (2) a 66% inhibition in the production of root-knot nematodes (Meloidogyne hapla) on field grown kidney beans (Phaseolus vulgaris Red Kidney); (3) a 20% decrease in the severity of Uromyces phaseoli infection of field grown kidney beans; and (4) either stimulated or inhibited development of halo blight on kidney bean (caused by Pseudomonas phaseolicola) depending upon the segment of the disease cycle in which the stress occurred: (a) simulated acid rain before inoculation stimulated disease development; (b) suspension of inoculum in acid rain decreased inoculum potential; and (c) acid rain after infection inhibited disease development. Results suggest that the pH of rain is a new environmental parameter of concern to plant pathologists.

  14. Intraocular pressure-lowering effect of oral paracetamol and its in vitro corneal penetration properties

    Directory of Open Access Journals (Sweden)

    Mohamed N

    2013-01-01

    Full Text Available Nabiel Mohamed, David MeyerDivision of Ophthalmology, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, South AfricaBackground: Several studies have confirmed the ability of cannabinoids to reduce intraocular pressure. Experimental data recently demonstrated unequivocally that the analgesic effect of paracetamol is due to its indirect action on cannabinoid receptors. The question then arises as to whether paracetamol can reduce intraocular pressure via its effect on intraocular cannabinoid receptors.Methods: A 2-week, prospective, randomized, controlled, single-center, parallel-group pilot study was carried out to determine the efficacy and safety of paracetamol 1 g orally administered every 6 hours in adult patients with primary or secondary open angle glaucoma as compared with topical levobunolol 0.5% twice a day. Patient well-being was closely monitored throughout the study and focused on hepatic safety in accordance with Drug-Induced Liver Injury Network criteria. The in vitro diffusion kinetics of acetaminophen in a phosphate-buffered solution in rabbit and human corneas was also investigated, with the view to a topical application.Results: Eighteen adult patients were enrolled in the study, with nine in the topical levobunolol group and nine in the oral paracetamol group. In the levobunolol group, the mean reduction in intraocular pressure at day 7 was 7.5 mmHg (P < 0.008 and at day 14 was 9.1 mmHg (P < 0.005, from a mean baseline intraocular pressure of 29.6 mmHg. The corresponding figures for the paracetamol group were 8.8 mmHg (P < 0.0004 at day 7 and 6.5 mmHg (P < 0.004 at day 14, from a mean baseline intraocular pressure of 29.4 mmHg. Both study regimens were well tolerated. No serious treatment-related adverse events were reported in either of the treatment groups. Liver function tests, systolic/diastolic blood pressure, or heart rate remained unchanged in both groups during the 2 weeks of the study. In

  15. Host-mediated effects of phytonutrients in ruminants: A review.

    Science.gov (United States)

    Oh, J; Wall, E H; Bravo, D M; Hristov, A N

    2017-07-01

    Plants produce an extensive array of organic compounds derived from secondary metabolism that may be useful in animal nutrition because of their chemical makeup. These plant-derived bioactive compounds, also referred to as phytonutrients (PN) or phytobiotics, have been shown to express antimicrobial activities against a wide range of bacteria, yeast, and fungi and have been investigated as rumen modifiers in ruminant nutrition. Studies have reported that PN may inhibit deamination of AA and methanogenesis in the rumen and shift fermentation toward propionate and butyrate. Most of the experiments, however, have been conducted in vitro, and responses have been highly variable and inconsistent in animal experiments. In addition, some studies have reported that PN had positive effects on productivity, although rumen fermentation was not affected. Other than antimicrobial effects in the gut, PN are known to bind specific receptors expressed in neurons, intestines, and other cells and exhibit related physiological effects in nonruminants. The receptor-mediated effects include immune responses, oxidative stress, and insulin secretion and activity. Some PN, due to their phenolic nature, are likely less susceptible to microbial degradation in the rumen and may exhibit activities postruminally, similar to their mode of action in nonruminant species. This opens a new area of research in ruminants, including effects of PN on the animal's immune system, postruminal nutrient use, and animal physiology. Although limited, studies with ruminants provide first evidence of PN's regulatory effects on the host responses. For example, PN were reported to regulate immune cells related to adaptive and innate immunity in challenged or nonchallenged dairy cows. Supplementation of PN reduced oxidative stress by decreasing lipid peroxidation and increasing endogenous antioxidants in ruminants. Additionally, insulin secretion and sensitivity were reportedly regulated by PN in dairy cows. The

  16. Effective Ancillary Services Market Designs on High Wind Power Penetration Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ela, E.; Kirby, B.; Navid, N.; Smith, J. C.

    2011-12-01

    This paper focuses on how the ancillary service market designs are implemented and how they may require changes on systems with greater penetrations of variable renewable energy suppliers, in particular wind power. Ancillary services markets have been developed in many of the restructured power system regions throughout the world. Ancillary services include the services that support the provision of energy to support power system reliability. The ancillary services markets are tied tightly to the design of the energy market and to the physics of the system and therefore careful consideration of power system economics and engineering must be considered in their design. This paper focuses on how the ancillary service market designs are implemented and how they may require changes on systems with greater penetrations of variable renewable energy suppliers, in particular wind power.

  17. Intrabronchial Microdialysis: Effects of Probe Localization on Tissue Trauma and Drug Penetration into the Pulmonary Epithelial Lining Fluid

    DEFF Research Database (Denmark)

    Rottbøll, Lisa Amanda Holm; Skovgaard, Kerstin; Barington, Kristiane

    2015-01-01

    (PELF). The objective of this study was to investigate the effect of intrabronchial microdialysis on the integrity of the bronchial epithelium. Microdialysis sampling in PELF in proximal (n=4) and distal bronchi (n=4) was performed after intravenous inulin and florfenicol administration in anaesthetized...... pigs. Inulin was used as a marker molecule of permeability of the epithelium, and florfenicol was used as test drug. Bronchial tissue was examined by histopathology (distal and proximal bronchi) and gene expression analysis (RT-qPCR, proximal bronchi) at the termination of the experiment (6.5hr...... probes suggesting initiation of an inflammatory response. The observed up-regulation is considered to have limited impact on drug penetration during short-term studies. Inulin penetrated the respiratory epithelium in both proximal and distal bronchi without any correlation to histopathological lesions...

  18. The effect of floral resources on parasitoid and host longevity

    DEFF Research Database (Denmark)

    Sigsgaard, Lene; Betzer, Cathrine; Naulin, Cyril

    2013-01-01

    to increase functional biodiversity, the longevity of C. aretas and its host A. comariana was assessed on 5 flowering species: buckwheat, Fagopyrum esculentum Moench (Caryophyllales: Polygonaceae); borage, Borago officinalis L. (Boraginaceae); strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae...

  19. Evidence of anti-inflammatory effect and percutaneous penetration of a topically applied fish oil preparation: a photoacoustic spectroscopy study

    Science.gov (United States)

    Ames, Franciele Q.; Sato, Francielle; de Castro, Lidiane V.; de Arruda, Laura L. M.; da Rocha, Bruno A.; Cuman, Roberto K. N.; Baesso, Mauro L.; Bersani-Amado, Ciomar A.

    2017-05-01

    This paper investigates the topical anti-inflammatory effect of a fish oil preparation (FOP) in a croton oil (CO) model of skin inflammation. The photoacoustic spectroscopy (PAS) was applied to estimate the percutaneous penetration of the FOP and as a model to evaluate the topical inflammatory response. After applying CO, the groups of mice received a topical application of a FOP on the left ear. The right ear received the vehicle that was used to dilute the CO. After 6 h, ear tissue was collected to determine the percent inhibition of edema, myeloperoxidase (MPO) activity, and cytokine levels and to perform PAS measurements. Treatment with FOP reduced edema and MPO activity, which was at least partially attributed to a decrease in the levels of tumor necrosis factor, interleukin-1β, interleukin-6, keratinocyte-derived chemokine, and monocyte chemoattractant protein-1. The topically applied FOP penetrated into the tissue and decreased the area of the bands that characterize inflamed tissue. The present results demonstrated the topical anti-inflammatory effect of the FOP. PAS suggests that FOP anti-inflammatory activity is linked with its ability to penetrate through the skin.

  20. Analytical and experimental studies on the strain rate effects in penetration of 10wt % ballistic gelatin

    Science.gov (United States)

    Liu, L.; Jia, Z.; Ma, X. L.; Fan, Y. R.

    2013-07-01

    This work concentrates on modeling the super-elastic behavior of 10wt% ballistic gelatin at 4°C and the mechanical responses at quasi-static and high-speed penetrations. Uniaxial compression and simple shearing experiments were carried out to determine the moduli in Mooney-Rivlin model describing the elastic behavior of gelatin at low strain rates. The failure mode is determined to be elastic fracture as the tensile stretch ratio exceeds a critical value. For high compression strain rates, the available results from the split Hopkinson pressure bar (SHPB) experiments for 10wt% gelatin were carefully examined and assessed. Linear relationship between the moduli and the strain rate is established. Based on these material parameters, an analytic solution of stress for the quasi-static and quasi-dynamic expansion of spherical cavity in gelatin is derived. As a consequence, the work needed to open unit volume of cavity, Ps, which is the key parameter in studying penetration problems, is linearly increasing with the characteristic strain rate. The application of Ps to our quasi-static and high-speed penetration experiments is discussed and assessed.

  1. The effects of host age, host nuclear background and temperature on phenotypic effects of the virulent Wolbachia strain popcorn in Drosophila melanogaster.

    Science.gov (United States)

    Reynolds, K Tracy; Thomson, Linda J; Hoffmann, Ary A

    2003-07-01

    Because of their obligate endosymbiotic nature, Wolbachia strains by necessity are defined by their phenotypic effects upon their host. Nevertheless, studies on the influence of host background and environmental conditions upon the manifestation of Wolbachia effects are relatively uncommon. Here we examine the behavior of the overreplicating Wolbachia strain popcorn in four different Drosophila melanogaster backgrounds at two temperatures. Unlike other strains of Wolbachia in Drosophila, popcorn has a major fitness impact upon its hosts. The rapid proliferation of popcorn causes cells to rupture, resulting in the premature death of adult hosts. Apart from this effect, we found that popcorn delayed development time, and host background influenced both this trait and the rate of mortality associated with infection. Temperature influenced the impact of popcorn upon host mortality, with no reduction in life span occurring in flies reared at 19 degrees. No effect upon fecundity was found. Contrary to earlier reports, popcorn induced high levels of incompatibility when young males were used in tests, and CI levels declined rapidly with male age. The population dynamics of popcorn-type infections will therefore depend on environmental temperature, host background, and the age structure of the population.

  2. Larval size in acanthocephalan parasites: Influence of intraspecific competition and effects on intermediate host behavioural changes

    Directory of Open Access Journals (Sweden)

    Dianne Lucile

    2012-08-01

    Full Text Available Abstract Background Parasites often face a trade-off between exploitation of host resources and transmission probabilities to the next host. In helminths, larval growth, a major component of adult parasite fitness, is linked to exploitation of intermediate host resources and is influenced by the presence of co-infecting conspecifics. In manipulative parasites, larval growth strategy could also interact with their ability to alter intermediate host phenotype and influence parasite transmission. Methods We used experimental infections of Gammarus pulex by Pomphorhynchus laevis (Acanthocephala, to investigate larval size effects on host behavioural manipulation among different parasite sibships and various degrees of intra-host competition. Results Intra-host competition reduced mean P. laevis cystacanth size, but the largest cystacanth within a host always reached the same size. Therefore, all co-infecting parasites did not equally suffer from intraspecific competition. Under no intra-host competition (1 parasite per host, larval size was positively correlated with host phototaxis. At higher infection intensities, this relationship disappeared, possibly because of strong competition for host resources, and thus larval growth, and limited manipulative abilities of co-infecting larval acanthocephalans. Conclusions Our study indicates that behavioural manipulation is a condition-dependant phenomenon that needs the integration of parasite-related variables to be fully understood.

  3. Sex-specific effects of a parasite evolving in a female-biased host population

    Directory of Open Access Journals (Sweden)

    Duneau David

    2012-12-01

    Full Text Available Abstract Background Males and females differ in many ways and might present different opportunities and challenges to their parasites. In the same way that parasites adapt to the most common host type, they may adapt to the characteristics of the host sex they encounter most often. To explore this hypothesis, we characterized host sex-specific effects of the parasite Pasteuria ramosa, a bacterium evolving in naturally, strongly, female-biased populations of its host Daphnia magna. Results We show that the parasite proliferates more successfully in female hosts than in male hosts, even though males and females are genetically identical. In addition, when exposure occurred when hosts expressed a sexual dimorphism, females were more infected. In both host sexes, the parasite causes a similar reduction in longevity and leads to some level of castration. However, only in females does parasite-induced castration result in the gigantism that increases the carrying capacity for the proliferating parasite. Conclusions We show that mature male and female Daphnia represent different environments and reveal one parasite-induced symptom (host castration, which leads to increased carrying capacity for parasite proliferation in female but not male hosts. We propose that parasite induced host castration is a property of parasites that evolved as an adaptation to specifically exploit female hosts.

  4. The effects of host age, host nuclear background and temperature on phenotypic effects of the virulent Wolbachia strain popcorn in Drosophila melanogaster.

    OpenAIRE

    Reynolds, K. Tracy; Thomson, Linda J; Ary A Hoffmann

    2003-01-01

    Because of their obligate endosymbiotic nature, Wolbachia strains by necessity are defined by their phenotypic effects upon their host. Nevertheless, studies on the influence of host background and environmental conditions upon the manifestation of Wolbachia effects are relatively uncommon. Here we examine the behavior of the overreplicating Wolbachia strain popcorn in four different Drosophila melanogaster backgrounds at two temperatures. Unlike other strains of Wolbachia in Drosophila, popc...

  5. Effect of two ram sperm capacitating media on acrosome reaction and zona-free hamster oocyte penetration test

    Directory of Open Access Journals (Sweden)

    Silvia Ferrari

    2000-01-01

    Full Text Available An in vitro zona-free hamster oocyte penetration test was utilized in 24 trials in order to evaluate the capacitation media used for ram sperm. A pool of fresh semen was collected from three crossed breed rams. Two semen drops were washed by centrifugation and incubated in high ionic strength treatment (HIS or in a defined medium with HEPES, on heat ewe serum and heparin. After the incubation to promote capacitation, simplified triple-stain technique was used to evaluate the spontaneous acrosome reaction of the capacitated sperm. Superovulation in 96 golden hamsters was induced by PMSG and hCG. The oocytes were treated with hyaluronidase and trypsin to remove, respectively, the cumulus cells and the zona pellucida. Oocytes and capacitated sperm were incubated during 3 hours for further penetration. Then, oocytes were fixed and stained, being evaluated under phase contrast microscope. No significant statistical difference (p >; 0.05 was found between media, concerning the penetration rate of the capacitated sperm and between number of sperm viable with acrosome reaction after the capacitation treatment using two different media. It was concluded that both media utilized were effective in capacitating ram sperm.

  6. Effect of ultrasonic streaming on intra-dentinal disinfection and penetration of calcium hydroxide paste in endodontic treatment

    Directory of Open Access Journals (Sweden)

    Marcela Paola Castro ARIAS

    Full Text Available ABSTRACT Objective The antimicrobial effect of ultrasonic agitation of calcium hydroxide (CH pastes in infected bovine dentin and their penetrability were evaluated using confocal laser scanning microscopy (CLSM and microbiological culture. Material and Methods Fifty-two bovine teeth were infected with Enterococcus faecalis using a new contamination protocol; then they received CH paste and were divided into groups with or without ultrasound. Ultrasonic agitation was conducted for 1 min with a plain point insert. After 15 d, the CLSM analyzed the viable and dead bacteria with Live and Dead assay. The dentinal wall debris was collected by burs, and the colony forming units (CFU/mL were counted. The penetrability of the paste inside dentinal tubules was tested using the B-rodamine dye. Results The calcium hydroxide paste showed better results with the use of ultrasonic agitation (p<0.05. Conclusion The ultrasonic agitation of CH paste increased its antimicrobial action and was responsible for intradentinal penetration with the fulfilment of the tubules.

  7. Effects of Pulsed Nd:YAG Laser Welding Parameters on Penetration and Microstructure Characterization of a DP1000 Steel Butt Joint

    National Research Council Canada - National Science Library

    Xin Xue; António B Pereira; Jose Amorim; Juan Liao

    2017-01-01

    Of particular importance and interest are the effects of pulsed Nd:YAG laser beam welding parameters on penetration and microstructure characterization of DP1000 butt joint, which is widely used in the automotive industry nowadays...

  8. Tumor-penetrating peptide fused to a pro-apoptotic peptide facilitates effective gastric cancer therapy.

    Science.gov (United States)

    Huang, Ying; Li, Xihan; Sha, Huizi; Zhang, Lianru; Bian, Xinyu; Han, Xiao; Liu, Baorui

    2017-04-01

    KLA (sequence, KLAKLAKKLAKLAK) is a peptide which leads to programmed cell death by disrupting the mitochondrial membrane. However, low penetration in tumors greatly limits its application and efficacy. To develop a KLA-based cancer therapy, KLA-iRGD, a recombinant protein was constructed. It consists of the KLA peptide and iRGD (CRGDKGPDC), a tumor-homing peptide with high penetration into tumor tissue and cells. The conjugated KLA exhibits pro-apoptotic activity to prevent the growth of a tumor once it is inside the cell. Once KLA-iRGD is internalized in cultured tumor cells, via the activation of the receptor neuropilin-1, it spreads extensively throughout the mass of the tumor. The recombinant KLA-iRGD protein showed antitumor activity in vivo in mice and in vitro in tumor cell lines. Repeated treatment with KLA-iRGD greatly prevented tumor growth, resulting in a considerable reduction in tumor volume. According to our data, KLA-iRGD may serve as a potential anticancer agent with limited systemic toxicity and high selectivity for the treatment of MKN45 gastric cancer, which may lead to the enhancement of new targeted anticancer agents.

  9. Effect of host polymer blends to phosphorescence emission | Alias ...

    African Journals Online (AJOL)

    ... pulsed UV excitation source of Xenon lamp. The results shows that there were changing in the phosphorescence emission and life time with difference host polymer. The explanation of phosphorescence emission has been supported by ZINDO calculation. Keywords: luminescence; phosphorescence, polymer blend ...

  10. The effect of host genetics on the gut microbiome

    NARCIS (Netherlands)

    Bonder, Marc Jan; Kurilshchikov, Aleksandr; Tigchelaar-Feenstra, Ettje; Mujagic, Zlatan; Imhann, Floris; Vila, Arnau Vich; Deelen, Patrick; Vatanen, Tommi; Schirmer, Melanie; Smeekens, Sanne P; Zhernakova, Daria V; Jankipersadsing, Soesma A; Jaeger, Martin; Oosting, Marije; Cenit, Maria Carmen; Masclee, Ad A M; Swertz, Morris A; Li, Yang; Kumar, Vinod; Joosten, Leo; Harmsen, Hermie; Weersma, Rinse K; Franke, Lude; Hofker, Marten H; Xavier, Ramnik J; Jonkers, Daisy; Netea, Mihai G; Wijmenga, Cisca; Fu, Jingyuan; Zhernakova, Alexandra

    2016-01-01

    The gut microbiome is affected by multiple factors, including genetics. In this study, we assessed the influence of host genetics on microbial species, pathways and gene ontology categories, on the basis of metagenomic sequencing in 1,514 subjects. In a genome-wide analysis, we identified

  11. Cognitive Penetration and Attention

    Science.gov (United States)

    Gross, Steven

    2017-01-01

    Zenon Pylyshyn argues that cognitively driven attentional effects do not amount to cognitive penetration of early vision because such effects occur either before or after early vision. Critics object that in fact such effects occur at all levels of perceptual processing. We argue that Pylyshyn’s claim is correct—but not for the reason he emphasizes. Even if his critics are correct that attentional effects are not external to early vision, these effects do not satisfy Pylyshyn’s requirements that the effects be direct and exhibit semantic coherence. In addition, we distinguish our defense from those found in recent work by Raftopoulos and by Firestone and Scholl, argue that attention should not be assimilated to expectation, and discuss alternative characterizations of cognitive penetrability, advocating a kind of pluralism. PMID:28275358

  12. EFFECTS OF THE PENETRATION OF WIND POWER IN THE BRAZILIAN ELECTRICITY MARKET

    Directory of Open Access Journals (Sweden)

    Milton M. Herrera

    2016-12-01

    Full Text Available Climate variability has been the main driver for renewables in the Brazilian electricity market. This article analyzes the vulnerabilities of the dependence on hydropower in renewable energy production due to climate variation, as well as wind power penetration in Brazil, given a set of wind industry policies. Despite Brazilian renewable energy increase, the study shows the impact in energy supply in north region, due to the lack of transmission infrastructure. In Brazil, the potential trade-offs between renewables growth, and transmission infrastructure inconsistencies in terms of policy implementation are not yet well analyzed. Simulation results show the potential conflicts between energy policies aimed at increasing the wind power supply and boundaries in transmission infrastructure.

  13. Effect of Impact and Penetration on Microstructural Evolution of High-performance Concretes

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Fei [ORNL; Mattus, Catherine H [ORNL; Wang, Jy-An John [ORNL; Dipaolo, Beverly P [ORNL

    2013-01-01

    Due to the increased concern of public safety in recent years, blast resistance of infrastructures has become an emerging research focus in the cement and concrete industry. Ultra High Performance Concrete (UHPC) with fiber reinforcement usually possesses compressive strengths greater than 200 MPa, which makes them promising candidates for blast-resistant building materials. In the current project, two UHPC materials, Ductal and ERDC-M, were subject to projectile penetration testing. The microstructural evolution due to projectile impact was examined via scanning electron microscopy and X-ray diffraction. Possible phase changes were observed in the impact volume, which was likely a result of the high temperature and high pressure induced by the impact.

  14. Marine Air Penetration: The Effect of Synoptic-scale Change on Regional Climate

    Science.gov (United States)

    Wang, M.; Ullrich, P. A.

    2016-12-01

    Marine air penetration (MAP) around the California San Francisco Bay Delta region has a pronounced impact on local temperature and air quality, and is highly correlated with inland wind penetration and hence wind power generation. Observational MAP criteria are defined based on the 900hPa across-shore wind speed greater than or equal to 3m/s at the Oakland radiosonde station, and a surface temperature difference greater than or equal to 7 degrees Celsius between two California Irrigation Management Information System (CIMIS) stations at Fresno, CA and Lodi, CA. This choice reflects marine cooling of Lodi, and was found to be highly correlated with inland specific humidity and breeze front activity. The observational MAP criteria were tuned based on small biases from Climate Forecast System Reanalysis (CFSR) to selected MAP days from CFSR, to identify synoptic-scale indicators associated with MAP events. A multivariate logistic regression model was constructed based on the selected five synoptic indicators from CFSR and demonstrated good model performance. Two synoptic-scale patterns were identified and analyzed out of the 32 categories from the regression model, suggesting a strong influence from the off-shore trough and the inland thermal ridge on MAP events. Future projection of MAP events included the 21st century Coupled Model Intercomparison Project Phase 5 (CMIP5), and Variable resolution in the Community Earth System Model (VR-CESM). Both showed no statistically significant trend associated with MAP events through the end of this century under both Representative Concentration Pathways (RCP) 2.6 and RCP 8.5.

  15. The effect of skin aging on the percutaneous penetration of chemicals through human skin

    Energy Technology Data Exchange (ETDEWEB)

    Roskos, K.V.

    1989-01-01

    Despite much research into the mechanisms of cutaneous aging and the identification of significant age-associated biological and biophysical changes within the skin, the question how does aging affect percutaneous absorption (PA) in vivo remains unanswered. The author has made in vivo measurements of PA in young (18-40 years) and old (> 65 years) subjects. Standard radiotracer methodology was employed and PA was quantified from the urinary excretion profiles of {sup 14}C radiolabel (corrected for incomplete renal elimination). Testosterone (TST), estradiol (EST), hydrocortisone (HC), benzoic acid (BA), acetylsalicylic acid (ASA) and caffeine (CAFF) have been studied. Penetration of HC, BA, ASA, and CAFF were significantly lower in aged subjects whereas TST and EST absorption were not distinguishable from the young controls. Thus it appears that aging can affect PA in vivo and that relatively hydrophilic compounds may be most sensitive. Work was done to elucidate whether the observations were related to documented skin aging changes. Cutaneous microcirculation efficiency suspected to decline with increasing age, could not be correlated with the observed penetration changes. However, in vivo infrared spectroscopic studies of aged stratum corneum (SC) reveal a decreased amount of epidermal lipid. The diminished lipid content implies a diminished dissolution medium for compounds administered to the skin surface. They hypothesize that the compounds most affected by a loss of SC lipids would be those compounds whose overall solubility is lowest (compounds with lower octanol-water partition coefficients, eg., HC, BA, ASA and CAFF). Conversely, a diminished lipid content may not affect dissolution into the SC of highly lipophilic compounds (e.g., TST and EST).

  16. A model of posttraumatic epilepsy after penetrating brain injuries: effect of lesion size and metal fragments.

    Science.gov (United States)

    Kendirli, M Tansel; Rose, Dominique T; Bertram, Edward H

    2014-12-01

    Penetrating brain injury (PBI) has the highest risk for inducing posttraumatic epilepsy, and those PBIs with retained foreign materials such as bullet fragments carry the greatest risk. This study examines the potential contribution of copper, a major component of bullets, to the development of epilepsy following PBI. Anesthetized adult male rats received a penetrating injury from the dorsal cortex to the ventral hippocampus from a high speed small bit drill. In one group of animals, copper wire was inserted into the lesion. Control animals had only the lesion or the lesion plus stainless steel wire (biologically inert foreign body). From 6 to up to 11 months following the injury the rats were monitored intermittently for the development of epilepsy with video-electroencephalography (EEG). A separate set of animals was examined for possible acute seizures in the week following the injury. Twenty-two of the 23 animals with copper wire developed chronic epilepsy, compared to three of the 20 control rats (lesion and lesion with stainless steel). Copper was associated with more extensive injury. The control rats with epilepsy had larger lesions. In the acute injury group, there was no difference in the incidence of seizures (83% lesion plus stainless steel, 70% lesion plus copper). Copper increases the risk for epilepsy and may increase damage over time, but there were no differences between the groups in the incidence of acute postinjury seizures. Lesion size may contribute to epilepsy development in lesion-only animals. Copper may be an independent risk factor for the development of epilepsy and possible secondary injury, but lesion size also contributes to the development of epilepsy. The consequences of prolonged exposure of the brain to copper observed in these animals may have clinical implications that require further evaluation. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  17. Effects of host heterogeneity on pathogen diversity and evolution

    DEFF Research Database (Denmark)

    Fleming-Davies, Arietta E; Dukic, Vanja; Andreasen, Viggo

    2015-01-01

    strategy for the pathogen: a low-transmission, low-variability type can coexist with the high-transmission type favoured by classical non-heterogeneity models. In addition, this tradeoff can help explain the extensive phenotypic variation we observed in field-collected pathogen isolates, in traits...... affecting virus fitness including transmission and environmental persistence. Similar heterogeneity tradeoffs might be a general mechanism promoting phenotypic variation in any pathogen for which hosts vary continuously in susceptibility.......Phenotypic variation is common in most pathogens, yet the mechanisms that maintain this diversity are still poorly understood. We asked whether continuous host variation in susceptibility helps maintain phenotypic variation, using experiments conducted with a baculovirus that infects gypsy moth...

  18. Phylosymbiosis: Relationships and Functional Effects of Microbial Communities across Host Evolutionary History

    Science.gov (United States)

    Brooks, Andrew W.; Kohl, Kevin D.; Brucker, Robert M.; van Opstal, Edward J.; Bordenstein, Seth R.

    2016-01-01

    Phylosymbiosis was recently proposed to describe the eco-evolutionary pattern, whereby the ecological relatedness of host-associated microbial communities parallels the phylogeny of related host species. Here, we test the prevalence of phylosymbiosis and its functional significance under highly controlled conditions by characterizing the microbiota of 24 animal species from four different groups (Peromyscus deer mice, Drosophila flies, mosquitoes, and Nasonia wasps), and we reevaluate the phylosymbiotic relationships of seven species of wild hominids. We demonstrate three key findings. First, intraspecific microbiota variation is consistently less than interspecific microbiota variation, and microbiota-based models predict host species origin with high accuracy across the dataset. Interestingly, the age of host clade divergence positively associates with the degree of microbial community distinguishability between species within the host clades, spanning recent host speciation events (~1 million y ago) to more distantly related host genera (~108 million y ago). Second, topological congruence analyses of each group's complete phylogeny and microbiota dendrogram reveal significant degrees of phylosymbiosis, irrespective of host clade age or taxonomy. Third, consistent with selection on host–microbiota interactions driving phylosymbiosis, there are survival and performance reductions when interspecific microbiota transplants are conducted between closely related and divergent host species pairs. Overall, these findings indicate that the composition and functional effects of an animal's microbial community can be closely allied with host evolution, even across wide-ranging timescales and diverse animal systems reared under controlled conditions. PMID:27861590

  19. Investigating the potential of essential oils as penetration enhancer for transdermal losartan delivery: Effectiveness and mechanism of action

    Directory of Open Access Journals (Sweden)

    Indu Vashisth

    2014-10-01

    Full Text Available The effect of tea tree oil (TTO, cumin oil (CO, rose oil (RO and aloe vera oil (AVO on the skin permeation of losartan potassium (LP was investigated. In vitro skin permeation studies were carried out using rat skin. The mechanism of skin permeation enhancement of LP by essential oils treatment was evaluated by FTIR, DSC, activation energy measurement and histopathological examination. Both concurrent ethanol/enhancer treatment and neat enhancer pretreatment of rat SC with all the oils produced significance increase in the LP flux over the control. The effectiveness of the oils as the penetration enhancers was found to be in the following descending order: AVO > RO > CO > TTO. However, only AVO was the only enhancer to provide target flux required to deliver the therapeutic transdermal dose of LP. FTIR and DSC spectra of the enhancer treated SC indicated that TTO, CO, RO and AVO increased the LP permeation by extraction of SC lipids. The results of thermodynamic studies and histopathological examination of AVO treated SC suggested additional mechanisms for AVO facilitated permeation i.e. transient reduction in barrier resistance of SC and intracellular transport by dekeratinization of corneocytes which may be attributed to the presence of triglycerides as constituents of AVO. It is feasible to deliver therapeutically effective dose of LP via transdermal route using AVO as penetration enhancer.

  20. Effects of LncRNA-HOST2 on cell proliferation, migration, invasion and apoptosis of human hepatocellular carcinoma cell line SMMC-7721.

    Science.gov (United States)

    Liu, Run-Tian; Cao, Jing-Lin; Yan, Chang-Qing; Wang, Yang; An, Cong-Jing; Lv, Hai-Tao

    2017-04-30

    The present study explored the effect of long non-coding RNA-human ovarian cancer-specific transcript 2 (LncRNA-HOST2) on cell proliferation, migration, invasion and apoptosis of human hepatocellular carcinoma (HCC) cell line SMMC-7721. HCC tissues and adjacent normal tissues from 162 HCC patients were collected. The HCC cell lines were assigned into the control group (regular culture), negative control (NC) group (transfected with siRNA) and experimental group (transfected with Lnc-HOST2 siRNA). Quantitative real-time PCR (qRT-PCR) was used to detect the expression of LncRNA-HOST2. Cell proliferation was detected by CCK-8 and colony-forming assays, cell apoptosis by flow cytometry and cell migration by Scratch test. Transwell assay was used to evaluate cell migration and invasion abilities. LncRNA-HOST2 expression in the HCC tissues increased 2-10 times than that in the adjacent normal tissues. Compared with the HL-7702 cell line, LncRNA-HOST2 expression in HepG2, SMMC-7721 and Huh7 cell lines was all up-regulated, but the SMMC-7721 cell had the highest Lnc-HOST2 expression. The LncRNA-HOST2 expression in the experimental group was down-regulated as compared with the control and NC groups. In comparison with the control and NC groups, cloned cells reduced, cell apoptosis increased, clone-forming ability weakened and inhibitory rate of colony formation increased in the experimental group. The cells migrating and penetrating into the transwell chamber were fewer in the experimental group than those in the control and NC groups. The experimental group exhibited slow wound healing and decreased cell migration area after 48 h. These findings indicate that LncRNA-HOST2 can promote cell proliferation, migration and invasion and inhibit cell apoptosis in human HCC cell line SMMC-7721. © 2017 The Author(s).

  1. Temperature-Mediated Effects of Host Alternation on the Adaptation of Myzus persicae (Hemiptera: Aphididae).

    Science.gov (United States)

    Li, Dan; Zhao, Huiyan; Gao, Huanhuan; Hu, Zuqing; Hu, Xiangshun

    2015-04-01

    Local adaptation, an important phenomenon in ecological speciation, occurs in Myzus persicae (Sulzer), with the tobacco-adapted line proposed as a subspecies. Recent studies showed that temperature could alter the selection strength and direction in host-herbivore interactions. To understand the formation of host-adapted speciation and the effects of temperature on host adaptation, the parthenogenetic progeny of an M. persicae egg were conditioned on two hosts for >10 generations. Then, their life table parameters were studied after reciprocal transfer under a temperature gradient. The results showed that aphids habituated on tobacco (Nicotiana tabacum L.) and rape (Brassica napus L.) had different optimal temperatures, including different upper thresholds of development and reproduction on original and alternative hosts. After habituation for >10 generations, local adaptation of aphids on the host of origin was formed, which was observed as the better performance of the native aphids compared with the foreign ones. The M. persicae that habituated on rape appeared more generalized to the host plants than the aphids that habituated on tobacco. The adaptation patterns of green peach aphids on two hosts varied differentially according to temperature, which verified the temperature-mediated effects of host selection on herbivores, implying the presence of a demographic basis of aphid seasonal migration. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Penetrability of nano-wollastonite into the poplar wood and its effect on wood durability and dimensional stability

    Directory of Open Access Journals (Sweden)

    davoud efhamisisi

    2017-08-01

    Full Text Available In recent years, much attention has been paid to nano technology for improving wood defects. Wollastonite as a mineral is commonly used in the production of plastic, ceramic and concrete. Wollastonite production in nano scale has increased interest in using it. Recently, a large number of studies have been carried out in Iran aiming to improve durability, dimensional stability, and flammability of wood and wood products using nano wollastonite. Based on the promising results obtained in these researchs, this study was conducted as a complementary investigation to verify nano-wollastonite penetrability into the wood as well as its effects on biological durability and dimensional stability. The results showed that nano-wollastonite could not penetrate into the xylem since wood texture serves as a filter against it. The treated samples with nano-wollastonite showed partly resistance against white rotting fungus, but this was lost after a short-time leaching. Nano-wollastonite had no effect on the water absorption and volumetric shrinkage of treated samples. Base on the results of this study, nano-wollastonite is not recommended for wood impregnation industry, at least when raw wood is concerned.

  3. The effect of multiple antireflective coatings and center thickness on resistance of polycarbonate spectacle lenses to penetration by pointed missiles.

    Science.gov (United States)

    Chou, B Ralph; Gupta, Alina; Hovis, Jeffery K

    2005-11-01

    Previous work has shown that the impact resistance to blunt missiles is affected by coatings applied to either CR-39 or polycarbonate lenses. We investigated the effects of multiple antireflection (minimum angle of resolution [MAR]) coatings on the resistance of polycarbonate lenses to puncture on impact by sharp, high-speed missiles. Four groups of surfaced plano polycarbonate lenses were investigated. Two groups had a scratch-resistant (SR) coating applied to both surfaces. One of these groups had a 2-mm center thickness and the other had a 3-mm center thickness. The other two groups of 2-mm and 3-mm thick lenses had a MAR coating applied over the SR coating. The lenses were impacted by a missile consisting of an industrial sewing machine needle mounted in a cylindrical aluminum carrier. The sharp missiles were able to pierce the lenses at speeds between 29.6 m/s and 46.2 m/s. Impact resistance was lowest for the thinner lenses and lenses with a MAR coating. The effect of the MAR and lens thickness was subadditive. We have confirmed previous observations that polycarbonate lenses are more susceptible to penetration by sharp, high-speed missiles than blunt missiles. We have also found that reducing lens center thickness and applying a MAR coating further reduces the penetration resistance. Therefore, the use of 2-mm center thickness and MAR-coated polycarbonate lenses should be discouraged for industrial eye protectors where sharp missile hazards are possible.

  4. Effect of permeation enhancers on the penetration mechanism of transfersomal gel of ketoconazole

    Directory of Open Access Journals (Sweden)

    Reshmy Rajan

    2012-01-01

    Full Text Available The aim of the present research work was to investigate the potential of transfersome formulations for transdermal delivery of Ketoconazole (KTZ. KTZ is a broad-spectrum antifungal agent that is active against a wide variety of fungi and yeasts. It is readily but incompletely absorbed after oral dosing and is highly variable. The transfersomes were formulated by lipid film hydration technique using Rotary vacuum Evaporator. The prepared transfersomes were converted into suitable gel formulation and is evaluated for their gel characteristics like pH, viscosity, spreadability, extrudability, homogeneity, drug content, etc. Suitable essential oils acting as natural permeation enhancers were added to the transfersomal formulation of KTZ for their release studies. Studies proved that addition of suitable permeation enhancers to the transfersomal formulation improved the release and permeation of KTZ, which showed that the permeation enhancers modify the barrier to penetration present in skin without itself undergoing any change. From the various essential oils which are used as permeation enhancers, the formulation containing Eucalyptus oil showed better in vitro release and permeation as compared with other formulations containing different permeation enhancers.

  5. Effects of silicon on the penetration and reproduction events of Meloidogyne exigua on coffee roots

    Directory of Open Access Journals (Sweden)

    Rodrigo Vieira Silva

    2015-06-01

    Full Text Available Considering that the root-knot nematode Meloidogyne exigua has caused great yield losses to coffee production in Brazil, this study aimed to determine whether the penetration and the reproduction events of this nematode on the roots of plants from two coffee cultivars with different levels of basal resistance to this nematode could be affected by silicon (Si. Coffee plants from the cultivars Catuaí and IAPAR 59, which are susceptible and resistant, respectively, to M. exigua, were grown in pots containing Si-deficient soil that was amended with either calcium silicate (+Si or calcium carbonate (–Si. The Si concentration on the root tissue significantly increased by 159 and 97% for the +Si plants from the cultivars Catuaí and IAPAR 59, respectively, compared to the –Si plants of these cultivars. The population of M. exigua, the number of galls and the number of eggs were significantly reduced on the roots of the +Si plants of the cultivars Catuaí and IAPAR 59 compared to the –Si plants of these cultivars. It was concluded that the development and reproduction events of M. exigua were negatively impacted on the roots of coffee plants supplied with Si.

  6. Effect of pretreating of host oil on coprocessing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wender, I.; Tierney, J.W.

    1995-10-01

    A petroleum vacuum resid (1,000 F+) was pretreated by catalytic hydrogenation and hydrocracking reactions and the pretreated resids (host oils) were then coprocessed with coal. The fraction of coal converted to soluble products and the yield of pentane-soluble oils were determined after coprocessing. The phenolic oxygen concentration of the oil product provided a means for estimating the fraction of coal liquids in the products; oils originating from coal had much higher concentrations of phenolic oxygen than those originating from petroleum. Resids that were pretreated by mild temperature hydrogenation reactions, where cracking was suppressed, became better host oils; when these pretreated resids were coprocessed with coal, more of the mixture was converted to tetrahydrofuran-soluble products. Depending on the pretreatment, the pentane-soluble oil yields following thermal coprocessing were either significantly lower or slightly higher than the oil yields obtained with untreated resid. The yield of oils was strongly affected by the concentration of coal in the feed. The presence of small amounts, less than 33% of coal, enhanced the conversion of petroleum resid to oils during coprocessing, although the increases were small. 91 refs.

  7. High-precision measurement of isotope effects on noncovalent host-guest interactions.

    Science.gov (United States)

    Mugridge, Jeffrey S; Bergman, Robert G; Raymond, Kenneth N

    2010-02-03

    The self-assembled supramolecular host [Ga(4)L(6)](12-) can bind cationic guest molecules to both the interior and exterior of the host assembly through noncovalent interactions. Very small equilibrium isotope effects (EIEs) have been precisely measured for the association of benzyltrimethylphosphonium isotopologues to the host exterior surface by adapting an NMR titration method originally developed by the Perrin group for measuring isotope effects on acidity constants. Deuteration of the phosphonium methyl groups was found to have a larger EIE than deuteration at the ring and benzyl positions, suggesting subtle differences in the noncovalent interactions between the host exterior and different guest C-H/D bonds. The application of this method to the measurement of EIEs on noncovalent host-guest interactions demonstrates the generality of this NMR technique in precisely measuring relative equilibrium constants.

  8. Potential Effect and Analysis of High Residential Solar Photovoltaic (PV Systems Penetration to an Electric Distribution Utility (DU

    Directory of Open Access Journals (Sweden)

    Jeffrey Tamba Dellosa

    2016-11-01

    Full Text Available The Renewable Energy Act of 2008 in the Philippines provided an impetus for residential owners to explore solar PV installations at their own rooftops through the Net-Metering policy. The Net-Metering implementation through the law however presented some concerns with inexperienced electric DU on the potential effect of high residential solar PV system installations. It was not known how a high degree of solar integration to the grid can possibly affect the operations of the electric DU in terms of energy load management. The primary objective of this study was to help the local electric DU in the analysis of the potential effect of high residential solar PV system penetration to the supply and demand load profile in an electric distribution utility (DU grid in the province of Agusan del Norte, Philippines. The energy consumption profiles in the year 2015 were obtained from the electric DU operating in the area. An average daily energy demand load profile was obtained from 0-hr to the 24th hour of the day based from the figures provided by the electric DU. The assessment part of the potential effect of high solar PV system integration assumed four potential total capacities from 10 Mega Watts (MW to 40 MW generated by all subscribers in the area under study at a 10 MW interval. The effect of these capacities were measured and analyzed with respect to the average daily load profile of the DU. Results of this study showed that a combined installations beyond 20 MWp coming from all subscribers is not viable for the local electric DU based on their current energy demand or load profile. Based from the results obtained, the electric DU can make better decisions in the management of high capacity penetration of solar PV systems in the future, including investment in storage systems when extra capacities are generated. Article History: Received July 15th 2016; Received in revised form Sept 23rd 2016; Accepted Oct 1st 2016; Available online How to Cite

  9. Effect of existence of cracks in concrete on depth of chloride penetration; Concrete no hibiware ga enbun shinto fukasa ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Iyoda, T.; Uomoto, T. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

    1998-10-01

    The results are reported of chloride penetration tests conducted for concrete without cracks and concrete with cracks for the examination of the effect of cracks on the depth of chloride penetration. It is reported that two types of concrete specimens of water/cement ratios of 50% and 70%, respectively, are prepared with reinforcement bars embedded therein, that they are subjected to bending load tests for crack initiation, and that they are next subjected to chloride penetration tests under conditions where the air temperature is 20degC, the water temperature is 20{+-}3degC, and the chloride concentration level is approximately 3%. It is stated that, as the result of the tests, it is found that the crack-free part of a specimen with cracks is roughly equal to a specimen without cracks in terms of the depth of chloride penetration, irrespective of the water/cement ratios, and that the depth of chloride penetration is in proportion approximately to the square root of the length of time of immersion in salt water. It is pointed out that the effect of cracks on the depth of chloride penetration in the cracked part of a specimen is related to the depth of cracks, but not dependent on the width of cracks on the specimen surface. 4 refs., 9 figs.

  10. Effect of adding powder on joint properties of laser penetration welding for dual phase steel and aluminum alloy

    Science.gov (United States)

    Zhou, D. W.; Liu, J. S.; Lu, Y. Z.; Xu, S. H.

    2017-09-01

    The experiments of laser penetration welding for dual phase steel and aluminum alloy were carried out, and the effect of adding Mn or Si powder on mechanical properties and microstructure of the weld was investigated. Some defects, such as spatter, inclusion, cracks and softening in heat affected zone (HAZ), can be avoided in welding joints, and the increased penetration depth is obtained by adding Mn or Si powder. The average tensile-shear strength of Si-added joint is 3.84% higher than that of Mn-added joint, and the strength of both joints exceeds that of no-added joint. In the case of adding Mn powder, small amount of liquid Al is mixed into steel molten pool, and the Al content increases in both sides of the weld, which leads to the increased weld width in aluminum molten pool. Thus, transverse area increases in jointing steel to aluminum, which is significant for the improved tensile-shear strength of joints. As far as adding Si powder is concerned, it is not the case, the enhancement of the joint properties benefits from improvement of metallurgical reaction.

  11. Penetration of Photovoltaics in Greece

    Directory of Open Access Journals (Sweden)

    Eugenia Giannini

    2015-06-01

    Full Text Available Recently, an interesting experiment was completed in Greece concerning photovoltaic penetration into the electricity production sector. Based on the relevant laws and in accordance to the related European directives, an explosive penetration process was completed in less than three years, resulting in a 7% share of photovoltaics in electricity production instead of the previous negligible share. The legislation was based on licensing simplification and generous feed-in-tariffs. This approach transformed photovoltaic technology from a prohibitively expensive to a competitive one. This work aims to summarize the relevant legislation and illustrate its effect on the resulting penetration. A sigmoid-shape penetration was observed which was explained by a pulse-type driving force. The return on investment indicator was proposed as an appropriate driving force, which incorporates feed-in-tariffs and turnkey-cost. Furthermore, the resulting surcharge on the electricity price due to photovoltaic penetration was also analyzed.

  12. Effect of Energy Storage in Increasing the Penetration of RES in the Remote Island of Agios Efstratios

    DEFF Research Database (Denmark)

    Kyriakidis, Ioannis; Braun, Philipp; Chaudhary, Sanjay

    2012-01-01

    Most of the inhabited Greek islands are not connected to the central electricity grid and their energy needs are satisfied by diesel power stations. The operation of such stations has negative economic and environmental effects related to the high transportation cost of fuels, increasing oil prices...... and emissions. The replacement of fossil fuelled stations with hybrid ones that combine renewable energy technologies with energy storage systems will provide a promising clean energy generation alternative and contribute to the limitation of the aforementioned drawbacks. The current paper deals...... with the integration of such a hybrid power system in the autonomous power system (APS) of the Greek island Agios Efstratios. The objective is to study the effect of energy storage (ES) in increasing the penetration of renewable energy sources (RES) in the hybrid system. Two storage technologies, based on lead...

  13. Penetration of pyrotechnic effects with SWIR laser gated viewing in comparison to VIS and thermal IR bands

    Science.gov (United States)

    Göhler, Benjamin; Lutzmann, Peter

    2016-10-01

    In this paper, the potential capability of short-wavelength infrared laser gated-viewing for penetrating the pyrotechnic effects smoke and light/heat has been investigated by evaluating data from conducted field trials. The potential of thermal infrared cameras for this purpose has also been considered and the results have been compared to conventional visible cameras as benchmark. The application area is the use in soccer stadiums where pyrotechnics are illegally burned in dense crowds of people obstructing visibility of stadium safety staff and police forces into the involved section of the stadium. Quantitative analyses have been carried out to identify sensor performances. Further, qualitative image comparisons have been presented to give impressions of image quality during the disruptive effects of burning pyrotechnics.

  14. TradeWind Deliverable 5.1: Effects of increasing wind power penetration on the power flows in European grids

    DEFF Research Database (Denmark)

    Lemström, Bettina; Uski-Joutsenvuo, Sanna; Holttinen, Hannele

    2008-01-01

    flow simulations with a grid and market model developed in TradeWind Work Package 3, led by Sintef Energy Research. VTT, Sintef Energy Research and Risø have carried out the simulations of the different scenarios, analysed the results and written Chapter 4 about the impact of wind power on cross......This report presents the main activities and results of Work Package 5 – Effects of increasing wind power penetration on the power flows in European grids in the TradeWind project. VTT is the leader of Work Package 5 and carries the overall responsibility of this report. The work is based on power......-border transmission. Risø has written section 4.2 about the impact of prediction errors of wind power production. VTT has carried out the model evaluation described in Chapter 3. Furthermore VTT has analysed the wind speed data, studied the moving weather effects and the capacity factor method presented in section 2...

  15. Effects of Tryptophan Content and Backbone Spacing on the Uptake Efficiency of Cell-Penetrating Peptides

    KAUST Repository

    Rydberg, Hanna A.

    2012-07-10

    Cell-penetrating peptides (CPPs) are able to traverse cellular membranes and deliver macromolecular cargo. Uptake occurs through both endocytotic and nonendocytotic pathways, but the molecular requirements for efficient internalization are not fully understood. Here we investigate how the presence of tryptophans and their position within an oligoarginine influence uptake mechanism and efficiency. Flow cytometry and confocal fluorescence imaging are used to estimate uptake efficiency, intracellular distribution and toxicity in Chinese hamster ovarian cells. Further, membrane leakage and lipid membrane affinity are investigated. The peptides contain eight arginine residues and one to four tryptophans, the tryptophans positioned either at the N-terminus, in the middle, or evenly distributed along the amino acid sequence. Our data show that the intracellular distribution varies among peptides with different tryptophan content and backbone spacing. Uptake efficiency is higher for the peptides with four tryptophans in the middle, or evenly distributed along the peptide sequence, than for the peptide with four tryptophans at the N-terminus. All peptides display low cytotoxicity except for the one with four tryptophans at the N-terminus, which was moderately toxic. This finding is consistent with their inability to induce efficient leakage of dye from lipid vesicles. All peptides have comparable affinities for lipid vesicles, showing that lipid binding is not a decisive parameter for uptake. Our results indicate that tryptophan content and backbone spacing can affect both the CPP uptake efficiency and the CPP uptake mechanism. The low cytotoxicity of these peptides and the possibilities of tuning their uptake mechanism are interesting from a therapeutic point of view. © 2012 American Chemical Society.

  16. Penetration testing using mobile devices

    CSIR Research Space (South Africa)

    Shelembe, S

    2012-10-01

    Full Text Available Slide 3 Previous/traditional methods ? Host-based vulnerability scanning ? Network based vulnerability scanning ? Application scanning ? Web Application Assessment Proxy ? CSIR 2012 Slide 4 Previous/traditional methods ? Advantage: more... Mobile Device Mobile OS Pen-testing application ? How it works Current Android hacking applications: ? WiFi Analyzer ? SpoofApp ? FaceNiff ? Penetrate Pro ? Anti-Android Network Toolkit ? ConnectBot ? Network Discovery ? Wireless Tether...

  17. The effect of final irrigation on the penetrability of an epoxy resin-based sealer into dentinal tubules: a confocal microscopy study.

    Science.gov (United States)

    Jardine, Alexander Pompermayer; Rosa, Ricardo Abreu da; Santini, Manuela Favarin; Wagner, Márcia; Só, Marcus Vinícius Reis; Kuga, Milton Carlos; Pereira, Jefferson Ricardo; Kopper, Patrícia Maria Poli

    2016-01-01

    The aim of this study was to compare the effect of QMix, BioPure MTAD, 17 % EDTA, and saline on the penetrability of a resin-based sealer into dentinal tubules using a confocal laser scanning microscope (CLSM) and to describe the cleaning of root canal walls by SEM. Eighty distobuccal roots from upper molars were selected and randomly divided into four groups (n = 20) before root canal preparation according to the solution used in the final rinse protocol (FRP): QG (QMix), MG (BioPure MTAD), EG (17 % EDTA), and CG (control group: saline). Ten roots of each group were prepared for SEM, and images (×2000) from the canal walls were acquired. The remaining canals were filled with a single gutta-percha cone and AH Plus with 0.1 % Rhodamine B. The specimens were horizontally sectioned at 4 mm from the apex, and the slices were analyzed in CLSM (×10). Sealer penetration was analyzed with Adobe Photoshop software. QG and EG presented similar amounts of sealer penetration (P > .05). MG and CG presented the lowest penetrability values (P < .05). The best results for smear layer removal of the apical third of the root canal were achieved by the QG and EG groups when compared with MG and CG (P < .05). Seventeen percent EDTA and QMix promoted sealer penetration superior to that achieved by BioPure MTAD and saline. Despite studies have not confirmed the relationship between sealing ability of endodontic sealers and their penetration in dentinal tubules, sealer penetration assumes importance, since endodontic sealers, unlike gutta-percha, are able to penetrate in dentinal tubules, isthmus, and accessory canals, filling the root canal system.

  18. Effect of heat treatment of wood on the morphology, surface roughness and penetration of simulated and human blood.

    Science.gov (United States)

    Rekola, J; Lassila, L V J; Nganga, S; Ylä-Soininmäki, A; Fleming, G J P; Grenman, R; Aho, A J; Vallittu, P K

    2014-01-01

    Wood has been used as a model material for the development of novel fiber-reinforced composite bone substitute biomaterials. In previous studies heat treatment of wood was perceived to significantly increase the osteoconductivity of implanted wood material. The objective of this study was to examine some of the changing attributes of wood materials that may contribute to improved biological responses gained with heat treatment. Untreated and 140°C and 200°C heat-treated downy birch (Betula pubescens Ehrh.) were used as the wood materials. Surface roughness and the effect of pre-measurement grinding were measured with contact and non-contact profilometry. Liquid interaction was assessed with a dipping test using two manufactured liquids (simulated blood) as well as human blood. SEM was used to visualize possible heat treatment-induced changes in the hierarchical structure of wood. The surface roughness was observed to significantly decrease with heat treatment. Grinding methods had more influence on the surface contour and roughness than heat treatment. The penetration of the human blood in the 200°C heat-treated exceeded that in the untreated and 140°C heat-treated materials. SEM showed no significant change due to heat treatment in the dry-state morphology of the wood. The results of the liquid penetration test support previous findings in literature concerning the effects of heat treatment on the biological response to implanted wood. Heat-treatment has only a marginal effect on the surface contour of wood. The highly specialized liquid conveyance system of wood may serve as a biomimetic model for the further development of tailored fiber-composite materials.

  19. Damped long-term host-parasite Red Queen coevolutionary dynamics: a reflection of dilution effects?

    Science.gov (United States)

    Decaestecker, Ellen; De Gersem, Herbert; Michalakis, Yannis; Raeymaekers, Joost A M

    2013-12-01

    An increase in biological diversity leads to a greater stability of ecosystem properties. For host-parasite interactions, this is illustrated by the 'dilution effect': a negative correlation between host biodiversity and disease risk. We show that a similar mechanism might stabilise host-parasite dynamics at a lower level of diversity, i.e. at the level of genetic diversity within host species. A long-term time shift experiment, based on a historical reconstruction of a Daphnia-parasite coevolution, reveals infectivity cycles with more stable amplitude in experienced than in naive hosts. Coevolutionary models incorporating an increase in host allelic diversity over time explain the detected asymmetry. The accumulation of resistance alleles creates an opportunity for the host to stabilise Red Queen dynamics. It leads to a larger arsenal enhancing the host performance in its coevolution with the parasite in which 'it takes all the running both antagonists can do to keep in the same place'. © 2013 John Wiley & Sons Ltd/CNRS.

  20. Effect of pretreating of host oil on coprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Hajdu, P.E.; Tierney, J.W.; Wender, I. [Univ. of Pittsburgh, PA (United States)

    1995-12-31

    The principal objective of this research was to determine if coprocessing performance (i.e., coal conversion and oil yield) could be significantly improved by pretreating the heavy resid prior to reacting it with coal. For this purpose, two petroleum vacuum resids (1000{degrees}F+), one from the Amoco Co. and another from the Citgo Co., were used as such and after they had been pretreated by catalytic hydrogenation and hydrocracking reactions. The pretreatments were aimed at improving the host oil by; (1) converting any aromatic structures in the petroleum to hydroaromatic compounds capable of donating hydrogen, (2) cracking the heavy oil to lower molecular weight material that might serve as a better solvent, (3) reducing the coking propensity of the heavy oil through the hydrogenation of polynuclear aromatic compounds, and (4) removing metals and heteroatoms that might poison a coprocessing catalyst. Highly dispersed catalysts, including fine particle Fe- and Mo-based, and dicobalt octacarbonyl, Co{sub 2}(CO){sub 8}, were used in this study. The untreated and pretreated resids were extensively characterized in order to determine chemical changes brought about by the pretreatments. The modified heavy oils were then coprocessed with an Illinois No. 6 coal as well as with a Wyodak coal, and compared to coprocessing with untreated resids under the same hydroliquefaction conditions. The amount of oil derived from coal was estimated by measuring the level of phenolic oxygen (derived mainly from coal) present in the oil products. Results are presented and discussed.

  1. The Effect of Host-Plant Phylogenetic Isolation on Species Richness, Composition and Specialization of Insect Herbivores: A Comparison between Native and Exotic Hosts.

    Directory of Open Access Journals (Sweden)

    Julio Miguel Grandez-Rios

    Full Text Available Understanding the drivers of plant-insect interactions is still a key issue in terrestrial ecology. Here, we used 30 well-defined plant-herbivore assemblages to assess the effects of host plant phylogenetic isolation and origin (native vs. exotic on the species richness, composition and specialization of the insect herbivore fauna on co-occurring plant species. We also tested for differences in such effects between assemblages composed exclusively of exophagous and endophagous herbivores. We found a consistent negative effect of the phylogenetic isolation of host plants on the richness, similarity and specialization of their insect herbivore faunas. Notably, except for Jaccard dissimilarity, the effect of phylogenetic isolation on the insect herbivore faunas did not vary between native and exotic plants. Our findings show that the phylogenetic isolation of host plants is a key factor that influences the richness, composition and specialization of their local herbivore faunas, regardless of the host plant origin.

  2. The Effect of Host Galaxies on Type Ia Supernovae in the SDSS-II Supernova Survey

    Energy Technology Data Exchange (ETDEWEB)

    Lampeitl, Hubert; /Portsmouth U., ICG; Smith, Mathew; /Cape Town U. /Portsmouth U., ICG; Nichol, Robert C.; /Portsmouth U., ICG; Bassett, Bruce; /South African Astron. Observ. /Cape Town U.; Cinabro, David; /Wayne State U.; Dilday, Benjamin; /Rutgers U., Piscataway; Foley, Ryan J.; /Harvard-Smithsonian Ctr. Astrophys.; Frieman, Joshua A.; /Chicago U. /Fermilab; Garnavich, Peter M.; /Notre Dame U.; Goobar, Ariel; /Stockholm U., OKC; Im, Myungshin; /Seoul Natl. U. /Rutgers U., Piscataway

    2010-05-01

    We present an analysis of the host galaxy dependencies of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2 to 3{sigma}) that SNe Ia are {approx_equal} 0.1 magnitudes brighter in passive host galaxies, than in star-forming hosts, after the SN Ia light curves have been standardized using the light curve shape and color variations: This difference in brightness is present in both the SALT2 and MCLS2k2 light curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R{sub V} {approx_equal} 1, while SNe Ia in star-forming hosts require R{sub V} {approx} 2. The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of > 4{sigma}) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.

  3. Network Penetration Testing and Research

    Science.gov (United States)

    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

  4. Effect of egg washing and correlation between eggshell characteristics and egg penetration by various Salmonella Typhimurium strains.

    Directory of Open Access Journals (Sweden)

    Vaibhav C Gole

    Full Text Available Salmonella is an important foodborne pathogen, causing an estimated 11,992 cases of infection in Australia per year. Egg or egg product related salmonellosis is a major concern for the egg industry. Worldwide, S. Typhimurium is one of the most common serovars identified in Salmonella food poisoning cases. The current study investigated the ability of five S. Typhimurium strains to penetrate washed and unwashed eggs using whole egg and agar egg penetration methods. All S. Typhimurium strains were able to penetrate eggshells and survive in egg albumen (at 20°C according to whole egg penetration results. Polymerase Chain Reaction results demonstrated that S. Typhimurium strain 2 (10(3 and 10(5 CFU/mL, and strain 5 (10(3 and 10(5 CFU/mL egg penetration was significantly higher (p<0.05 in washed eggs when compared to unwashed eggs. Statistical analysis of the agar penetration experiment indicated that S. Typhimurium was able to penetrate washed eggs at a significantly higher rate when compared to unwashed eggs (p<0.05. When compared to unwashed eggs, washed eggs also had significantly damaged cuticles. Statistical analysis also indicated that eggshell penetration by S. Typhimurium was related to various eggshell ultrastructural features such as cap quality, alignment, erosion, confluence, Type B bodies and cuticle cover.

  5. Enhancing Tumor Penetration of Nanomedicines.

    Science.gov (United States)

    Sun, Qingxue; Ojha, Tarun; Kiessling, Fabian; Lammers, Twan; Shi, Yang

    2017-05-08

    Tumor-targeted nanomedicines have been extensively applied to alter the drawbacks and enhance the efficacy of chemotherapeutics. Despite the large number of preclinical nanomedicine studies showing initial success, their therapeutic benefit in the clinic has been rather modest, which is partially due to the inefficient tumor penetration caused by the tumor microenvironment (high density of cells and extracellular matrix, increased interstitial fluid pressure). Furthermore, tumor penetration of nanomedicines is significantly influenced by physicochemical characteristics, such as size, surface chemistry, and shape. The effect of size on tumor penetration has been exploited to design nanomedicines with switchable size to tackle this challenge. Moreover, several pharmacological and physical approaches have been developed to enhance the tumor penetration of nanomedicines, by penetration-promoting ligands, intratumoral drug release, and modulating the tumor microenvironment and vasculature. Overall, these efforts have resulted in nanomedicines with better tumor penetration properties and with enhanced therapeutic efficacy. Future research should be directed to penetration-promoting strategies with broad applicability and with high translational potential.

  6. Intronic microRNAs support their host genes by mediating synergistic and antagonistic regulatory effects

    Directory of Open Access Journals (Sweden)

    Krumsiek Jan

    2010-04-01

    Full Text Available Abstract Background MicroRNA-mediated control of gene expression via translational inhibition has substantial impact on cellular regulatory mechanisms. About 37% of mammalian microRNAs appear to be located within introns of protein coding genes, linking their expression to the promoter-driven regulation of the host gene. In our study we investigate this linkage towards a relationship beyond transcriptional co-regulation. Results Using measures based on both annotation and experimental data, we show that intronic microRNAs tend to support their host genes by regulation of target gene expression with significantly correlated expression patterns. We used expression data of three differentiating cell types and compared gene expression profiles of host and target genes. Many microRNA target genes show expression patterns significantly correlated with the expressions of the microRNA host genes. By calculating functional similarities between host and predicted microRNA target genes based on GO annotations, we confirm that many microRNAs link host and target gene activity in an either synergistic or antagonistic manner. Conclusions These two regulatory effects may result from fine tuning of target gene expression functionally related to the host or knock-down of remaining opponent target gene expression. This finding allows to extend the common practice of mapping large scale gene expression data to protein associated genes with functionality of co-expressed intronic microRNAs.

  7. Effect of EndoActivator and Er,Cr:YSGG laser activation of Qmix, as final endodontic irrigant, on sealer penetration: A Confocal microscopic study.

    Science.gov (United States)

    Chaudhry, Sarika; Yadav, Sudha; Talwar, Sangeeta; Verma, Mahesh

    2017-02-01

    Through chemomechanical debridement of the root canal is a primary requisite for successful endodontic therapy. Thus the aim of this study was to evaluate the effects of using QmiX alone, QmiX with EndoActivator and QmiX with Er,Cr:YSGG laser for final irrigation on sealer penetration into the dentinal tubules. 75 extracted human mandibular premolar teeth were treated with sodium hypochlorite (NaOCl) irrigation. The samples were divided into 5 groups according to the final irrigation solution used: (1) 17% EDTA and 2.5% NaOCl, (2) QmiX (3) QmiX with Er,Cr:YSGG laser and (4) QmiX with EndoActivator (5) 2.5%NaOCl. All teeth were obturated using cold lateral condensation technique with gutta percha and AH 26 sealer (Dentsply; DeTrey,Konstanz, Germany) labeled with Rhodamine B dye. The teeth were sectioned at distances of 2 and 5 from root apex. Total percentage and maximum depth of sealer penetration were measured using confocal laser scanning microscopy. Results of one way Anova analysis showed that there was a significant difference in the percentage and depth of sealer penetration among all groups at 3 and 5 mm level sections (P groups maximum sealer penetration was recorded for Er,Cr:YSGG laser activated group. Greater depth of sealer penetration was recorded at 5mm as compared to 3mm in all the groups. Activation of QMix using EndoActivator and Er,Cr:YSGG laser enhanced the sealer penetration at apical and middle third. Thus Er,Cr:YSGG laser and EndoActivator may act as an appropriate adjunct during chemomechanical preparation of the root canal. Key words:EndoActivator, Er,Cr:YSGG laser, Qmix, confocal microscopy, sealer penetration.

  8. Ex-vivo and live animal models are equally effective training for the management of a penetrating cardiac injury.

    Science.gov (United States)

    Izawa, Yoshimitsu; Hishikawa, Shuji; Muronoi, Tomohiro; Yamashita, Keisuke; Maruyama, Hiroyuki; Suzukawa, Masayuki; Lefor, Alan Kawarai

    2016-01-01

    Live tissue models are considered the most useful simulation for training in the management for hemostasis of penetrating injuries. However, these models are expensive, with limited opportunities for repetitive training. Ex-vivo models using tissue and a fluid pump are less expensive, allow repetitive training and respect ethical principles in animal research. The purpose of this study is to objectively evaluate the effectiveness of ex-vivo training with a pump, compared to live animal model training. Staff surgeons and residents were divided into live tissue training and ex-vivo training groups. Training in the management of a penetrating cardiac injury was conducted for each group, separately. One week later, all participants were formally evaluated in the management of a penetrating cardiac injury in a live animal. There are no differences between the two groups regarding average years of experience or previous trauma surgery experience. All participants achieved hemostasis, with no difference between the two groups in the Global Rating Scale score (ex-vivo: 25.2 ± 6.3, live: 24.7 ± 6.3, p = 0.646), blood loss (1.6 ± 0.7, 2.0 ± 0.6, p = 0.051), checklist score (3.7 ± 0.6, 3.6 ± 0.9, p = 0.189), or time required for repair (101 s ± 31, 107 s ± 15, p = 0.163), except overall evaluation (3.8 ± 0.9, 3.4 ± 0.9, p = 0.037). The internal consistency reliability and inter-rater reliability in the Global Rating Scale were excellent (0.966 and 0.953 / 0.719 and 0.784, respectively), and for the checklist were moderate (0.570 and 0.636 / 0.651 and 0.607, respectively). The validity is rated good for both the Global Rating Scale (Residents: 21.7 ± 5.6, Staff: 28.9 ± 4.7, p = 0.000) and checklist (Residents: 3.4 ± 0.9, Staff Surgeons: 3.9 ± 0.3, p = 0.003). The results of self-assessment questionnaires were similarly high (4.2-4.9) with scores in self-efficacy increased after

  9. Temporal dynamics of direct reciprocal and indirect effects in a host-parasite network.

    Science.gov (United States)

    Pilosof, Shai; Fortuna, Miguel A; Vinarski, Maxim V; Korallo-Vinarskaya, Natalia P; Krasnov, Boris R

    2013-09-01

    1. Temporal variation in the direct and indirect influence that hosts and parasites exert on each other is still poorly understood. However, variation in species' influence due to species and interactions turnover can have important consequences for host community dynamics and/or for parasite transmission dynamics, and eventually for the risk of zoonotic diseases. 2. We used data on a network of small mammals and their ectoparasites surveyed over 6 years to test hypotheses exploring (i) the temporal variability in direct and indirect influences species exert on each other in a community, and (ii) the differences in temporal variability of direct/indirect influences between temporally persistent (TP) and temporally intermittent species. 3. We modelled the temporal variation in (i) direct reciprocal influence between hosts and parasites (hosts providing resources to parasites and parasites exploiting the resources of hosts), using an asymmetry index, and (ii) indirect influence among species within a community (e.g. facilitation of parasite infestation by other parasites), using betweenness centrality. We also correlated asymmetry and centrality to examine the relationship between them. 4. Network dynamics was determined by TP species but even those species had strong among-species heterogeneity in the temporal variation of the direct/indirect effects they exerted. In addition, there was a significant positive linear correlation between asymmetry and centrality. 5. We conclude that the temporal dynamics of host-parasite interactions is driven by TP hosts. However, even within this group of persistent species, some exhibit large temporal variation, such that the functional roles they play (e.g. in promoting parasite transmission) change over time. In addition, parasites having a large negative impact on hosts are also those facilitating the spread of other parasites through the entire host community. Our results provide new insights into community dynamics and can be

  10. Perturbation of host cell cytoskeleton by cranberry proanthocyanidins and their effect on enteric infections.

    Directory of Open Access Journals (Sweden)

    Kevin Harmidy

    Full Text Available Cranberry-derived compounds, including a fraction known as proanthocyanidins (PACs exhibit anti-microbial, anti-infective, and anti-adhesive properties against a number of disease-causing organisms. In this study, the effect of cranberry proanthocyanidins (CPACs on the infection of epithelial cells by two enteric bacterial pathogens, enteropathogenic Escherichia coli (EPEC and Salmonella Typhimurium was investigated. Immunofluorescence data showed that actin pedestal formation, required for infection by enteropathogenic Escherichia coli (EPEC, was disrupted in the presence of CPACs. In addition, invasion of HeLa cells by Salmonella Typhimurium was significantly reduced, as verified by gentamicin protection assay and immunofluorescence. CPACs had no effect on bacterial growth, nor any detectable effect on the production of bacterial effector proteins of the type III secretion system. Furthermore, CPACs did not affect the viability of host cells. Interestingly, we found that CPACs had a potent and dose-dependent effect on the host cell cytoskeleton that was evident even in uninfected cells. CPACs inhibited the phagocytosis of inert particles by a macrophage cell line, providing further evidence that actin-mediated host cell functions are disrupted in the presence of cranberry CPACs. Thus, although CPAC treatment inhibited Salmonella invasion and EPEC pedestal formation, our results suggest that this is likely primarily because of the perturbation of the host cell cytoskeleton by CPACs rather than an effect on bacterial virulence itself. These findings have significant implications for the interpretation of experiments on the effects of CPACs on bacteria-host cell interactions.

  11. Nanoparticles Penetrate into the Multicellular Spheroid-on-Chip: Effect of Surface Charge, Protein Corona, and Exterior Flow.

    Science.gov (United States)

    Huang, Ke; Boerhan, Rena; Liu, Changming; Jiang, Guoqiang

    2017-12-04

    Nanoparticles (NPs) are widely studied as tumor targeted vehicles. The penetration of NPs into the tumor is considered as a major barrier for delivery of NPs into tumor cell and a big challenge to translate NPs from lab to the clinic. The objective of this study is to know how the surface charge of NPs, the protein corona surrounding the NPs, and the fluid flow around the tumor surface affect the penetration and accumulation of NPs into the tumor, through in vitro penetration study based on a spheroid-on-chip system. Surface decorated polystyrene (PS) NPs (100 nm) carrying positive and negative surface charge were loaded to the multicellular spheroids under static and flow conditions, in the presence or absence of serum proteins. NP penetration was investigated by confocal laser microscopy scanning followed with quantitative image analysis. The results reveal that negatively charged NPs are attached more on the spheroid surface and easier to penetrate into the spheroids. Protein corona, which is formed surrounding the NPs in the presence of serum protein, changes the surface properties of the NPs, weakens the NP-cell affinity, and, therefore, results in lower NP concentration on the spheroid surface but might facilitate deeper penetration. The exterior fluid flow enhances the interstitial flow into the spheroid, which benefits the penetration but also strips the NPs (especially the NPs with protein corona) on the spheroid surface, which decreases the penetration flux significantly. The maximal penetration was obtained by applying negatively charged NPs without protein corona under the flow condition. We hope the present study will help to understand the spatiotemporal performance of drug delivery NPs and inform the rational design of NPs with highly defined drug accumulation localized at a target site.

  12. Effect of different potting systems; inoculation time; nematode density and sources of cereal cyst nematode (Heterodera filipjevi) on juvenile penetration into wheat root system.

    Science.gov (United States)

    Pariyar, S R; Dababat, A A; Nicol, J M; Sikora, R A

    2010-01-01

    Investigations were designed to optimize testing systems for screening wheat breeding lines for resistance to Heterodera filipjevi. The effects of: 1) plant potting systems 2) inoculum level and time of inoculation 3) and type of inoculum of H. filipjevi on detection accuracy were examined in growth chamber experiments in Turkey. The rate of nematode penetration in the highly susceptible variety Bezostaya was used as the base measurement of efficacy. The results showed that the highest level of penetration coupled with high level of germination was obtained in plastic tubes (13 cm long x 3 cm in diam.) when compared to both small flower pots (400 cm3) and smaller plastic tubes (10.2 cm long x 0.8 cm in diam.). The highest rate of nematode penetration into wheat root system was obtained by inoculating the seedlings with 1000 J2 per plant. However, inoculation with 200 J2 at sowing or 200 J2 at sowing plus an additional 200 J2 after germination improved percent penetration when compared to inoculation with 600 or 1000 J2/plant at sowing. The test on the optimum form of inoculum showed that inoculating the seedling with J2's gave the highest rate of nematode penetration over inoculum with eggs or cysts. The results of these experiments demonstrated that screening wheat for resistance can be optimized by raising the seedlings in plastic tubes and inoculating them with 400 J2.

  13. Effect of a Fusion Peptide by Covalent Conjugation of a Mitochondrial Cell-Penetrating Peptide and a Glutathione Analog Peptide

    Directory of Open Access Journals (Sweden)

    Carmine Pasquale Cerrato

    2017-06-01

    Full Text Available Previously, we designed and synthesized a library of mitochondrial antioxidative cell-penetrating peptides (mtCPPs superior to the parent peptide, SS31, to protect mitochondria from oxidative damage. A library of antioxidative glutathione analogs called glutathione peptides (UPFs, exceptional in hydroxyl radical elimination compared with glutathione, were also designed and synthesized. Here, a follow-up study is described, investigating the effects of the most promising members from both libraries on reactive oxidative species scavenging ability. None of the peptides influenced cell viability at the concentrations used. Fluorescence microscopy studies showed that the fluorescein-mtCPP1-UPF25 (mtgCPP internalized into cells, and spectrofluorometric analysis determined the presence and extent of peptide into different cell compartments. mtgCPP has superior antioxidative activity compared with mtCPP1 and UPF25 against H2O2 insult, preventing ROS formation by 2- and 3-fold, respectively. Moreover, we neither observed effects on mitochondrial membrane potential nor production of ATP. These data indicate that mtgCPP is targeting mitochondria, protecting them from oxidative damage, while also being present in the cytosol. Our hypothesis is based on a synergistic effect resulting from the fused peptide. The mitochondrial peptide segment is targeting mitochondria, whereas the glutathione analog peptide segment is active in the cytosol, resulting in increased scavenging ability.

  14. Host Plant Effects on Halyomorpha halys (Hemiptera: Pentatomidae) Nymphal Development and Survivorship.

    Science.gov (United States)

    Acebes-Doria, Angelita L; Leskey, Tracy C; Bergh, J Christopher

    2016-03-24

    Halyomorpha halys(Stål) (Hemiptera: Pentatomidae) is a highly polyphagous invasive species and an important pest of orchard crops in the United States. In the Mid-Atlantic region, wild hosts ofH. halysare common in woodlands that often border orchards, andH. halysmovement from them into orchards poses ongoing management issues. To improve our understanding of host plant effects onH. halyspopulations at the orchard-woodland interface, nymphal survivorship, developmental duration, and adult fitness (size and fresh weight) on apple (Malus domesticaBorkh.), peach (Prunus persica(L.) Batsch), Tree of Heaven (Ailanthus altissima(Mill.) Swingle), and northern catalpa (Catalpa speciosa(Warder)) were examined in laboratory studies. Specifically, we investigated nymphal performance on the foliage and fruiting structures of those hosts and on single- versus mixed-host diets, as well as the effects of host phenology on their suitability. Nymphal performance was poor on a diet of foliage alone, regardless of host. When fruiting structures were combined with foliage, peach was highly suitable for nymphal development and survivorship, whereas apple, Tree of Heaven, and catalpa were less so, although nymphal survival on Tree of Heaven was much greater later in the season than earlier. Mixed-host diets yielded increased nymphal survivorship and decreased developmental duration compared with diets of suboptimal single hosts. Adult size and weight were generally greater when they developed from nymphs reared on mixed diets. The implications of our results to the dispersal behavior, establishment, and management ofH. halysare discussed. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Effect of host plant on gypsy moth diet and biological efficacy of Btk preparations

    Directory of Open Access Journals (Sweden)

    Milanović Slobodan

    2006-01-01

    Full Text Available The effect of two host plants, Turkey oak (Quercus cerris L and black poplar (Populus nigra L on gypsy moth (Lymantria dispar L development was researched. The effect of host plant was determined based on the parameters which characterize the diet, growth and efficacy of conversion of ingested food of the third instar caterpillars. Along with the effect on development, the effect of host plant on the efficacy of biological preparation based on the bacterium Bacillus thuringiensis var. kurstaki in gypsy moth caterpillar suppression was also researched. The differences in parameters characterizing the diet, growth, and efficacy of ingested food between experimental groups of caterpillars grown on poplar and Turkey oak leaves are explained by the differences in the chemical composition of the leaves of these tree species. The efficacy of Btk preparation is conditioned by the mechanism and content of different groups of defense substances in the leaves of the applied tree species.

  16. Modelling the effect of structural QSAR parameters on skin penetration using genetic programming

    Science.gov (United States)

    Chung, K. K.; Do, D. Q.

    2010-09-01

    In order to model relationships between chemical structures and biological effects in quantitative structure-activity relationship (QSAR) data, an alternative technique of artificial intelligence computing—genetic programming (GP)—was investigated and compared to the traditional method—statistical. GP, with the primary advantage of generating mathematical equations, was employed to model QSAR data and to define the most important molecular descriptions in QSAR data. The models predicted by GP agreed with the statistical results, and the most predictive models of GP were significantly improved when compared to the statistical models using ANOVA. Recently, artificial intelligence techniques have been applied widely to analyse QSAR data. With the capability of generating mathematical equations, GP can be considered as an effective and efficient method for modelling QSAR data.

  17. Effects of magnetic islands on resonant field penetration and toroidal torques at slow plasma flow

    Science.gov (United States)

    Li, L.; Liu, Y. Q.; Wang, N.; Zhong, F. C.; Luan, Q.; Wang, Y.

    2017-12-01

    The presence of a chain of magnetic islands, produced by externally applied tri-dimensional fields at a rational surface, is numerically found to have significant effects on the resonant response, as well as on the associated toroidal torques, in a toroidal tokamak plasma with conventional aspect ratio, strong shaping, and in the regime of slow toroidal flow. With an ad hoc assumption of the local flattening of the equilibrium pressure profile by the islands, it is found that the primary effect is the increasing of the resonant response by islands, at slow flow, due to the reduction of the favourable average curvature effect. This also leads to the reduction of the toroidal torques, in particular that associated with the neoclassical toroidal viscosity. Partial or complete flattening of the local pressure profile, depending on the island size, results in partial or full recovering of the so called constant-ψ plasma response regime. Computational results are well fitted by analytic models for the two extreme cases: the case of complete flattening and the case of no flattening of the local pressure.

  18. Effects of Sizes and Conformations of Fish-Scale Collagen Peptides on Facial Skin Qualities and Transdermal Penetration Efficiency

    Directory of Open Access Journals (Sweden)

    Huey-Jine Chai

    2010-01-01

    Full Text Available Fish-scale collagen peptides (FSCPs were prepared using a given combination of proteases to hydrolyze tilapia (Oreochromis sp. scales. FSCPs were determined to stimulate fibroblast cells proliferation and procollagen synthesis in a time- and dose-dependent manner. The transdermal penetration capabilities of the fractionationed FSCPs were evaluated using the Franz-type diffusion cell model. The heavier FSCPs, 3500 and 4500 Da, showed higher cumulative penetration capability as opposed to the lighter FSCPs, 2000 and 1300 Da. In addition, the heavier seemed to preserve favorable coiled structures comparing to the lighter that presents mainly as linear under confocal scanning laser microscopy. FSCPs, particularly the heavier, were concluded to efficiently penetrate stratum corneum to epidermis and dermis, activate fibroblasts, and accelerate collagen synthesis. The heavier outweighs the lighter in transdermal penetration likely as a result of preserving the given desired structure feature.

  19. Corneal first-surface aberration analysis of the biomechanical effects of astigmatic keratotomy and a microkeratome cut after penetrating keratoplasty.

    Science.gov (United States)

    Kohnen, Thomas; Bühren, Jens

    2005-01-01

    Astigmatic keratotomy (AK) was performed in a patient after penetrating keratoplasty (PKP) for keratoconus to reduce high post-PKP astigmatism. The procedure led to a significant decrease in astigmatism, but corneal higher-order aberrations (HOAs) increased. After PKP, the patient was scheduled for 2-step laser in situ keratomileusis (LASIK) to correct myopia and astigmatism. One day after the microkeratome cut, a decrease of -2.75 diopters in the spherical equivalent (SE) was noted. Although subjective manifest cylinder and corneal spherical aberrations were marginally affected, a marked decrease in coma and other HOAs could be observed. One month after the cut, the SE was unchanged. Excimer laser ablation was not performed as the patient was satisfied with the result and refused further treatment. This case shows that AK cuts can induce HOAs and a single microkeratome cut performed in corneal grafts can have strong biomechanical effects on lower-order aberrations and HOAs. If LASIK is planned after PKP, a 2-step approach is recommended to anticipate biomechanical effects and avoid overcorrection or undercorrection.

  20. Fullerene C60 Penetration into Leukemic Cells and Its Photoinduced Cytotoxic Effects

    Science.gov (United States)

    Franskevych, D.; Palyvoda, K.; Petukhov, D.; Prylutska, S.; Grynyuk, I.; Schuetze, C.; Drobot, L.; Matyshevska, O.; Ritter, U.

    2017-01-01

    Fullerene C60 as a representative of carbon nanocompounds is suggested to be promising agent for application in photodynamic therapy due to its unique physicochemical properties. The goal of this study was to estimate the accumulation of fullerene C60 in leukemic cells and to investigate its phototoxic effect on parental and resistant to cisplatin leukemic cells. Stable homogeneous water colloid solution of pristine C60 with average 50-nm diameter of nanoparticles was used in experiments. Fluorescent labeled C60 was synthesized by covalent conjugation of C60 with rhodamine B isothiocyanate. The results of confocal microscopy showed that leukemic Jurkat cells could effectively uptake fullerene C60 from the medium. Light-emitting diode lamp (100 mW cm-2, λ = 420-700 nm) was used for excitation of accumulated C60. A time-dependent decrease of viability was detected when leukemic Jurkat cells were exposed to combined treatment with C60 and visible light. The cytotoxic effect of photoexcited C60 was comparable with that induced by H2O2, as both agents caused 50% decrease of cell viability at 24 h at concentrations about 50 μM. Using immunoblot analysis, protein phosphotyrosine levels in cells were estimated. Combined action of C60 and visible light was followed by decrease of cellular proteins phosphorylation on tyrosine residues though less intensive as compared with that induced by H2O2 or protein tyrosine kinase inhibitor staurosporine. All tested agents reduced phosphorylation of 55, 70, and 90 kDa proteins while total suppression of 26 kDa protein phosphorylation was specific only for photoexcited C60.

  1. Titanium Dioxide Nanoparticle Penetration into the Skin and Effects on HaCaT Cells

    Directory of Open Access Journals (Sweden)

    Matteo Crosera

    2015-08-01

    Full Text Available Titanium dioxide nanoparticles (TiO2NPs suspensions (concentration 1.0 g/L in synthetic sweat solution were applied on Franz cells for 24 h using intact and needle-abraded human skin. Titanium content into skin and receiving phases was determined. Cytotoxicity (MTT, AlamarBlue® and propidium iodide, PI, uptake assays was evaluated on HaCat keratinocytes after 24 h, 48 h, and seven days of exposure. After 24 h of exposure, no titanium was detectable in receiving solutions for both intact and damaged skin. Titanium was found in the epidermal layer after 24 h of exposure (0.47 ± 0.33 μg/cm2 while in the dermal layer, the concentration was below the limit of detection. Damaged skin, in its whole, has shown a similar concentration (0.53 ± 0.26 μg/cm2. Cytotoxicity studies on HaCaT cells demonstrated that TiO2NPs induced cytotoxic effects only at very high concentrations, reducing cell viability after seven days of exposure with EC50s of 8.8 × 10−4 M (MTT assay, 3.8 × 10−5 M (AlamarBlue® assay, and 7.6 × 10−4 M (PI uptake, index of a necrotic cell death. Our study demonstrated that TiO2NPs cannot permeate intact and damaged skin and can be found only in the stratum corneum and epidermis. Moreover, the low cytotoxic effect observed on human HaCaT keratinocytes suggests that these nano-compounds have a potential toxic effect at the skin level only after long-term exposure.

  2. Fullerene C60 Penetration into Leukemic Cells and Its Photoinduced Cytotoxic Effects.

    Science.gov (United States)

    Franskevych, D; Palyvoda, K; Petukhov, D; Prylutska, S; Grynyuk, I; Schuetze, C; Drobot, L; Matyshevska, O; Ritter, U

    2017-12-01

    Fullerene C60 as a representative of carbon nanocompounds is suggested to be promising agent for application in photodynamic therapy due to its unique physicochemical properties. The goal of this study was to estimate the accumulation of fullerene C60 in leukemic cells and to investigate its phototoxic effect on parental and resistant to cisplatin leukemic cells. Stable homogeneous water colloid solution of pristine C60 with average 50-nm diameter of nanoparticles was used in experiments. Fluorescent labeled C60 was synthesized by covalent conjugation of C60 with rhodamine B isothiocyanate. The results of confocal microscopy showed that leukemic Jurkat cells could effectively uptake fullerene C60 from the medium. Light-emitting diode lamp (100 mW cm-2, λ = 420-700 nm) was used for excitation of accumulated C60. A time-dependent decrease of viability was detected when leukemic Jurkat cells were exposed to combined treatment with C60 and visible light. The cytotoxic effect of photoexcited C60 was comparable with that induced by H2O2, as both agents caused 50% decrease of cell viability at 24 h at concentrations about 50 μM. Using immunoblot analysis, protein phosphotyrosine levels in cells were estimated. Combined action of C60 and visible light was followed by decrease of cellular proteins phosphorylation on tyrosine residues though less intensive as compared with that induced by H2O2 or protein tyrosine kinase inhibitor staurosporine. All tested agents reduced phosphorylation of 55, 70, and 90 kDa proteins while total suppression of 26 kDa protein phosphorylation was specific only for photoexcited C60.The cytotoxic effect of C60 in combination with visible light irradiation was demonstrated also on leukemic L1210 cells both sensitive and resistant to cisplatin. It was shown that relative value of mitochondrial membrane potential measured with tetramethylrhodamine ethyl ester perchlorate (TMRE) probe was lower in resistant cells in comparison with

  3. Assessment of the percutaneous penetration of indomethacin from soybean oil microemulsion: effects of the HLB value of mixed surfactants.

    Science.gov (United States)

    Chen, Liangmei; Tan, Fengping; Wang, Jinfeng; Liu, Feng

    2012-01-01

    The objective of this study was to evaluate the influence of the ratios or the hydrophile-lipophile balance (HLB) values of Cremophor EL and Span 80 on the phase behavior of the O/W microemulsions and the percutaneous absorption and penetration of indomethacin microemulsions. The existence of microemulsion regions is investigated in quaternary systems composed of soybean oil/Cremophor EL and Span 80 (mixed surfactants)/diethylene glycol monoethyl ether (cosurfactant)/water by constructing pseudo-ternary phase diagrams at various Cremophor EL/Span 80 ratios. In addition, five microemulsion formulations with various mixed surfactants HLB values were evaluated by in vitro penetration experiments using mouse skin and Franz diffusion cells. The flux and amount of indomethacin penetration from 5 microemulsion formulations were significantly different from the control, and the enhance ratios ranged from 2.38 to 4.68 and 2.11 to 4.23, respectively. The HLB value of mixed surfactants in the formulations was a principal factor in determining the percutaneous penetration of the drug. The flux and amount of drug penetration increased gradually with increasing content of the lipophilic surfactant Span 80 and skin retention was highest for mixed surfactants with a HLB value of 7.6. Therefore, it is suggested that the presence of mixed surfactants was beneficial in the formation of O/W microemulsions and enhanced percutaneous penetration of indomethacin.

  4. Effect of the characteristics of granular media on dynamic penetration test - Numerical study using 2D - DEM

    Science.gov (United States)

    Tran, Quoc Anh; Chevalier, Bastien; Breul, Pierre

    2017-06-01

    The paper presents a numerical study on the influence of the properties of granular media on light dynamic penetration test results. A numerical model based on the Discrete Element Method (DEM) in 2 dimensions has been carried out. The model is able to reproduce the penetration tests in dynamic conditions. The model provide for each impact, the load-penetration curve that presents the evolution of reaction forces of granular media acting on the tip of the penetration test. The load - penetration curves are investigated in terms of tip resistance and analyzed by using the Discrete Fourier Transform in order to study the oscillations of the curves. The influence of the properties of granular media on the load-penetration curve has been investigated. We concentrated on the influence of particle friction and sample compacity. Besides the known results obtained in the literature by the dynamic tip resistance analysis for macroscopic response, we found that for a particle friction greater than 0.5, tip resistance and oscillations of signal are stable. Concerning the sample compacity, although variation of volume fraction is tight (ϕ = 0.817 - 0.844), a clear variation in terms of tip resistance and amplitude spectrum is highlighted.

  5. Intellectual Property Rights and the productivity effects of MNE affiliates on host-country firms

    NARCIS (Netherlands)

    Smeets, R.A.L.M.; Vaal, A. de

    2016-01-01

    In this paper we investigate the impact of increased Intellectual Property Rights (IPR) protection on the productivity effects that MNE affiliates exert on local host-country firms. Conceptually, we argue that IPR protection has two opposing effects: On the one hand, it weakens the productivity

  6. Stability, transdermal penetration, and cutaneous effects of ascorbic acid and its derivatives.

    Science.gov (United States)

    Stamford, Nicholas P J

    2012-12-01

    Topically applied antioxidants exert their benefits by offering protection from damaging free radicals and over-the-counter cosmeceuticals incorporating antioxidants are among the most popular anti-aging products available. One potent antioxidant of particular note, vitamin C, has been extensively utilized because it possesses a variety of other cutaneous benefits including photoprotection from UV A & B, neocollagenesis, inhibition of melanogenesis and improvement of a variety of inflammatory skin disorders. However, the instability of this water-soluble vitamin, together with difficulties associated with its topical delivery, has presented issues for the formulation chemist. This article reviews the scientific data and clinical studies that underpin the stability, percutaneous absorption, and cutaneous effects of vitamin C together with its commonly utilized, commercially available derivatives. © 2012 Wiley Periodicals, Inc.

  7. Effect of photon-initiated photoacoustic streaming, passive ultrasonic, and sonic irrigation techniques on dentinal tubule penetration of irrigation solution: a confocal microscopic study.

    Science.gov (United States)

    Akcay, Merve; Arslan, Hakan; Mese, Merve; Durmus, Nazlı; Capar, Ismail Davut

    2016-12-05

    The aim of this in vitro study was to evaluate the efficacy of different irrigation techniques including laser-activated irrigation using an erbium:yttrium-aluminum-garnet (Er:YAG) laser with a novel tip design (photon-induced photoacoustic streaming (PIPS)), Er:YAG laser with Preciso tip, sonic activation, and passive ultrasonic activation on the final irrigation solution penetration into dentinal tubules by using a laser scanning confocal microscope. In this study, 65 extracted single-rooted human mandibular premolars were instrumented up to size 40 and randomly divided into 5 groups (n = 13) based on the activation technique of the final irrigation solution as follows: conventional irrigation (control group), sonic activation, passive ultrasonic activation, Er:YAG-PIPS tip activation, and Er:YAG-Preciso tip activation. In each group, 5 mL of 5% NaOCl labeled with fluorescent dye was used during the activation as the final irrigation solution. Specimens were sectioned at 2.5 and 8 mm from the apex and then examined under a confocal microscope to calculate the dentinal tubule penetration area. Data were analyzed using two-way analysis of variance (ANOVA) and Tukey's post hoc tests (P = 0.05). Both Er:YAG laser (Preciso/PIPS) activations exhibited a significantly higher penetration area than the other groups (P penetration than the sonic activation group and the control group. Statistically significant differences were also found between each root canal third (coronal > middle > apical) (P penetration area into the dentinal tubules. The activation of the irrigant and the creation of the streaming with the Er:YAG laser have a positive effect on the irrigant penetration.

  8. Effects of Endosulfan on Predator-Prey Interactions Between Catfish and Schistosoma Host Snails.

    Science.gov (United States)

    Monde, Concillia; Syampungani, Stephen; Van den Brink, Paul J

    2016-08-01

    The effect of the pesticide endosulfan on predator-prey interactions between catfish and Schistosoma host snails was assessed in static tank experiments. Hybrid catfish (Clarias gariepinus × C. ngamensis) and Bulinus globosus were subjected to various endosulfan concentrations including an untreated control. The 48- and 96-h LC50 values for catfish were 1.0 and Schistosoma host snails using fish may be affected in endosulfan-polluted aquatic systems of Southern Africa because it has been found present at concentrations that are indicated to cause lethal effects on the evaluated hybrid catfish and to inhibit the predation of snails by this hybrid catfish.

  9. Importance Of Penetration Testing For Legacy Operating System

    Directory of Open Access Journals (Sweden)

    Poorvi Bhatt

    2017-12-01

    Full Text Available Penetration testing is very important technique to find vulnerabilities in commercial networks. There are various techniques for ethical hacking via penetration testing. This report explains a white hat hacker approach of penetration testing. I have performed this test on private network where three PCs are connected through LAN via switch and without firewall. This network is not connected with Internet. All the PCs have windows operating system. The attacker host has windows server 2003 with Service Pack1 second host has windows XP with Service Pack 2 and third host has windows 2000 with service pack 4.

  10. Phenological synchrony between a butterfly and its host plants: Experimental test of effects of spring temperature.

    Science.gov (United States)

    Posledovich, Diana; Toftegaard, Tenna; Wiklund, Christer; Ehrlén, Johan; Gotthard, Karl

    2018-01-01

    Climate-driven changes in the relative phenologies of interacting species may potentially alter the outcome of species interactions. Phenotypic plasticity is expected to be important for short-term response to new climate conditions, and differences between species in plasticity are likely to influence their temporal overlap and interaction patterns. As reaction norms of interacting species may be locally adapted, any such climate-induced change in interaction patterns may vary among localities. However, consequences of spatial variation in plastic responses for species interactions are understudied. We experimentally explored how temperature affected synchrony between spring emergence of a butterfly, Anthocharis cardamines, and onset of flowering of five of its host plant species across a latitudinal gradient. We also studied potential effects on synchrony if climate-driven northward expansions would be faster in the butterflies than in host plants. Lastly, to assess how changes in synchrony influence host use we carried out an experiment to examine the importance of the developmental stage of plant reproductive structures for butterfly oviposition preference. In southern locations, the butterflies were well-synchronized with the majority of their local host plant species across temperatures, suggesting that thermal plasticity in butterfly development matches oviposition to host plant development and that thermal reaction norms of insects and plants result in similar advancement of spring phenology in response to warming. In the most northern region, however, relative phenology between the butterfly and two of its host plant species changed with increased temperature. We also show that the developmental stage of plants was important for egg-laying, and conclude that temperature-induced changes in synchrony in the northernmost region are likely to lead to shifts in host use in A. cardamines if spring temperatures become warmer. Northern expansion of butterfly

  11. Effects of vacuum-ultraviolet irradiation on copper penetration into low-k dielectrics under bias-temperature stress

    Energy Technology Data Exchange (ETDEWEB)

    Guo, X.; Zheng, H.; Xue, P.; Shohet, J. L. [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); King, S. W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States); Nishi, Y. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-01-05

    The effects of vacuum-ultraviolet (VUV) irradiation on copper penetration into non-porous low-k dielectrics under bias-temperature stress (BTS) were investigated. By employing x-ray photoelectron spectroscopy depth-profile measurements on both as-deposited and VUV-irradiated SiCOH/Cu stacks, it was found that under the same BTS conditions, the diffusion depth of Cu into the VUV-irradiated SiCOH is higher than that of as-deposited SiCOH. On the other hand, under the same temperature-annealing stress (TS) without electric bias, the Cu distribution profiles in the VUV-irradiated SiCOH were same with that for the as-deposited SiCOH. The experiments suggest that in as-deposited SiCOH, the diffused Cu exists primarily in the atomic state, while in VUV-irradiated SiCOH, the diffused Cu is oxidized by the hydroxyl ions (OH{sup −}) generated from VUV irradiation and exists in the ionic state. The mechanisms for metal diffusion and ion injection in VUV irradiated low-k dielectrics are discussed.

  12. Integral Length Scale Effects on JP-8 Spray Penetration and Ignition at Elevated Pressure and Temperature Conditions

    Science.gov (United States)

    Kurman, Matthew; Tess, Michael; Bravo, Luis; Kweon, Chol-Bum

    2014-11-01

    The effect of the integral length scale on global spray diagnostics was examined for non-reacting and reacting JP-8 sprays. The scales were set by varying the nominal nozzle diameter from 90 μm, 100 μm, and 147 μm, resulting in the ranges of Re (6.7 × 104 - 9.9 × 104) and We (1.3 × 106 - 1.7 × 106) setting the spray in the fully atomization mode. A high temperature (900-1000 K) high pressure (60-100 bar) flow through chamber was used to conduct experiments at relevant compression ignition engine operating conditions. Each fuel injector was characterized with an injection analyzer to determine the rate of injection and injected fuel mass. High speed near simultaneous Mie and schlieren images were acquired to determine the liquid and vapor penetration lengths of the non-reacting spray. Ignition delay experiments were conducted by measuring the start of formation of OH radicals. A numerical investigation was also carried out to provide additional insights into the behavior of each spray with the specified conditions. The quantitative results presented will aid in the overall advancement of fuel injector designs and ultimately lead to optimized engines.

  13. Models for the effects of host movement in vector-borne disease systems.

    Science.gov (United States)

    Cosner, Chris

    2015-12-01

    Host and/or vector movement patterns have been shown to have significant effects in both empirical studies and mathematical models of vector-borne diseases. The processes of economic development and globalization seem likely to make host movement even more important in the future. This article is a brief survey of some of the approaches that have been used to study the effects of host movement in analytic mathematical models for vector-borne diseases. It describes the formulation and interpretation of various types of spatial models and describes a few of the conclusions that can be drawn from them. It is not intended to be comprehensive but rather to provide sufficient background material and references to the literature to serve as an entry point into this area of research for interested readers. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Effects of orchard host plants on the oviposition preference of the oriental fruit moth (Lepidoptera: Tortricidae).

    Science.gov (United States)

    Myers, Clayton T; Hull, Larry A; Krawczyk, Grzegorz

    2006-08-01

    Recently, the oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), has emerged as a major problem on apples (Malus spp.) grown in the mid-Atlantic and midwestern United States, despite its historically important and frequent occurrence as a peach (Prunus spp.) pest. It is possible that host-driven biological phenomena may be contributing to changes in G. molesta population dynamics resulting in outbreaks in apple. Studies were designed to examine the effects of host plants on oviposition behavior, in an effort to clarify the host association status of eastern U.S. populations and also to gain insight into how pest modeling and management efforts may be altered to take into account various host-associated effects. G. molesta adults exhibited ovipositional preference for nonbearing peach trees over nonbearing apple trees in close-range choice tests conducted in the field, regardless of the larval host origin. A significant preference for peach shoots over apple shoots was observed on six of 12 sampling dates with a wild G. molesta population at the interface of adjacent peach and apple blocks. Numbers of eggs found on apple fruit were higher after peach fruit were harvested and apple fruit began to approach maturity (during the flight period for third and fourth brood adults). Possible implications for population modeling and integrated management of G. molesta are discussed.

  15. No Effect of Host Species on Phenoloxidase Activity in a Mycophagous Beetle.

    Directory of Open Access Journals (Sweden)

    Vincent Formica

    Full Text Available Ecological immunology is an interdisciplinary field that helps elucidate interactions between the environment and immune response. The host species individuals experience have profound effects on immune response in many species of insects. However, this conclusion comes from studies of herbivorous insects even though species of mycophagous insects also inhabit many different host species. The goal of this study was to determine if fungal host species as well as individual, sex, body size, and host patch predict one aspect of immune function, phenoloxidase activity (PO. We sampled a metapopulation of Bolitotherus cornutus, a mycophagous beetle in southwestern Virginia. B. cornutus live on three species of fungus that differ in nutritional quality, social environment, and density. A filter paper phenoloxidase assay was used to quantify phenoloxidase activity. Overall, PO activity was significantly repeatable among individuals (0.57 in adult B. cornutus. While there was significant variance among individuals in PO activity, there were surprisingly no significant differences in PO activity among subpopulations, beetles living on different host species, or between the sexes; there was also no effect of body size. Our results suggest that other factors such as age, genotype, disease prevalence, or natal environment may be generating variance among individuals in PO activity.

  16. Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest

    Science.gov (United States)

    The Janzen-Connell (JC) hypothesis provides a powerful framework for explaining the maintenance of tree diversity in tropical forests. Its central tenet -- that recruits experience high mortality near conspecifics and at high densities -- assumes a degree of host specialization in interactions betwe...

  17. Effects of host-plant population size and plant sex on a specialist leaf-miner

    Science.gov (United States)

    Bañuelos, María-José; Kollmann, Johannes

    2011-03-01

    Animal population density has been related to resource patch size through various hypotheses such as those derived from island biogeography and resource concentration theory. This theoretical framework can be also applied to plant-herbivore interactions, and it can be modified by the sex of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size was negatively related to leaf-miner prevalence, with larger egg and mine densities in small populations. Percentage of eggs hatching and developing into mines, and percentage of adult flies emerging from mines also differed among host populations, but were not related to population size or host cover. Feeding punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively correlated with emergence of the larvae. The inverse effects of host population size were not in line with predictions based on island biogeography and resource concentration theory. We discuss how a thorough knowledge of the immigration behaviour of this fly might help to understand the patterns found.

  18. Effects of orchard host plants (apple and peach) on development of oriental fruit moth (Lepidoptera: Tortricidae).

    Science.gov (United States)

    Myers, Clayton T; Hull, Larry A; Krawczyk, Grzegorz

    2007-04-01

    Studies were designed to examine the effects of host plants (apple, Malus domestica Borkh., and peach, Prunus persica L.) on the development of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae). Oriental fruit moth larvae developed faster on peach than on apple, both on fruit as well as on growing terminal shoots. On fruit, these differences were shown to cause significant changes in both the rate (approximately 20-60 degree-days earlier emergence on peach than on apple) and patterns of adult emergence among several cultivars of peaches and apples. Slopes of female emergence plots varied by host in 2003, with emergence occurring over a longer period on peach cultivars than on apple cultivars (with one exception). Slopes of male emergence curves did not differ by cultivar in 2003. These host-driven effects could impact the efficacy of traditional pest management approaches and probably complicate efforts to predictively model G. molesta populations in mixed cultivar orchards. Such developmental effects may help to explain previously observed differences in patterns of pheromone trap captures in peach versus apple orchards. Host-associated effects should be incorporated into future models to develop more realistic predictive tools and thus improve integrated pest management efforts.

  19. Effects of Endosulfan on Predator–Prey Interactions Between Catfish and Schistosoma Host Snails

    NARCIS (Netherlands)

    Monde, Concillia; Syampungani, Stephen; Brink, van den Paul J.

    2016-01-01

    The effect of the pesticide endosulfan on predator–prey interactions between catfish and Schistosoma host snails was assessed in static tank experiments. Hybrid catfish (Clarias gariepinus × C. ngamensis) and Bulinus globosus were subjected to various endosulfan concentrations including an

  20. Effect of host species diversity on multiparasite systems in rodent communities.

    Science.gov (United States)

    Rendón-Franco, Emilio; Muñoz-García, Claudia I; Romero-Callejas, Evangelina; Moreno-Torres, Karla I; Suzán, Gerardo

    2014-01-01

    Reduced species diversity has been suggested to increase transmission rates and prevalence of infectious diseases. While this theory has been studied mostly in single pathogen systems, little is known regarding multiple pathogens systems in vertebrates at the community level. The aim of this study was to evaluate the effect of host richness and diversity on multiple parasite systems on a local scale. We captured small rodents and collected feces in three different vegetation types in a natural protected area in Janos, Chihuahua, Mexico. The flotation technique was used to identify parasite eggs or oocysts. Analysis of linear correlations was conducted between parasite prevalence and host and parasite diversity and richness. Negative correlation was detected between parasite prevalence and host diversity (p = 0.02 r(2) =-0.86), but no significant correlations was detected between parasite prevalence and host richness or parasite diversity or richness. Our study shows that at local scale, host diversity could affect multiple parasite systems in the same way that single pathogens do. Further studies should be performed on larger temporal and spatial scales to more thoroughly investigate the correlation observed in our analysis.

  1. Ripple Effects: An Exclusive Host National Context Produces More Perceived Discrimination among Immigrants

    DEFF Research Database (Denmark)

    Simonsen, Kristina Bakkær

    2016-01-01

    that perceived discrimination should be strongest among immigrants in host national societies with an exclusive self-image. This hypothesis is examined by use of multilevel regressions on cross-national survey data from 18 Western European countries. It is found that where exclusive attitudes are widespread......This article examines the perceived discrimination of immigrants; a group for whom experiences of discrimination can be damaging for their long-term commitment and identification with the national core group. Taking its point of departure in the literature on national identity, the article argues...... in the host population, the percentage of immigrants who perceive themselves to be part of a group discriminated against is significantly greater, all else being equal. In addition, there is a cross-level interaction effect of host national inclusivity and ethnic minority identity which suggests...

  2. Effect of the pretreatment of silicone penetrant on the performance of the chromium-free chemfilm coated on AZ91D magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Shiuan-Ho, E-mail: 1802186169@qq.com [College of Electronic Information and Mechatronic Engineering, Zhaoqing University, Zhaoqing Road, Duanzhou District, Zhaoqing, Guangdong, 526061 (China); Niu, Liyuan [Department of Material Engineer, Zhejiang Industry & Trade Vocational Colledge, WenZhou, 325000 (China); Su, Yichang [Department of Material Engineer, Zhejiang Industry & Trade Vocational Colledge, WenZhou, 325000 (China); College of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 (China); Wang, Wenquan [College of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 (China); Tong, Xian [Department of Material Engineer, Zhejiang Industry & Trade Vocational Colledge, WenZhou, 325000 (China); Li, Guangyu [College of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 (China)

    2016-03-01

    This paper reported a new pretreatment of silicone penetrant for forming the chromium-free chemfilm (chemical conversion coating) on the surface of an AZ91D magnesium (Mg) alloy. Through applying micro current on the pretreatment solution, an uniform mask membrane was created on the surface of a Mg alloy. By using X-ray diffraction (XRD), scanning electron microscope (SEM), and Energy Dispersive Spectrometer (EDS) analyses, the chromium-free chemfilm on a Mg alloy was examined to analyze the performance during initial, middle, and final deposition periods. As a result, the pretreatment of silicone penetrant can effectively prevent the chemfilm from cracking, improve the anticorrosion ability and nucleation rate of the chromium-free chemfilm on a Mg alloy, and make the surface crystallization transform a long strip into short axis shape. - Highlights: • An AZ91D Mg alloy was pretreated by using silicone penetrant. • Surface crystallization of the chemfilm on a silicone-pretreated Mg alloy is smooth. • The pretreatment of silicone penetrant for a Mg alloy enhanced the anticorrosion ability.

  3. Nitrogen and water inputs to tomato plant do not trigger bottom-up effects on a leafminer parasitoid through host and non-host exposures.

    Science.gov (United States)

    Dong, Yong-Cheng; Han, Peng; Niu, Chang-Ying; Zappalà, Lucia; Amiens-Desneux, Edwige; Bearez, Philippe; Lavoir, Anne-Violette; Biondi, Antonio; Desneux, Nicolas

    2017-10-02

    Bottom-up and top-down forces are major components of biological control against pests in an agro-ecosystem. Understanding the multi-trophic interactions between plants and secondary consumers would help optimize pest control strategies. We manipulated nitrogen and/or water inputs to tomato plants (Solanum lycopersicum) to test whether these manipulations could trigger bottom-up effects on the parasitoid Necremnus tutae via host (Tuta absoluta) and/or non-host (Bemisia tabaci) exposures, and compared the control efficacy of N. tutae on T. absoluta in the presence and absence of B. tabaci. The results showed no cascading effects of plant nitrogen and/or water inputs on N. tutae via either host or non-host exposure. The bottom-up force was mitigated by chewing or sap-feeding insect consumers at the second energy level. By contrast, the top-down force on T. absoluta from parasitoids was enhanced by an additionally provided non-host, which could produce alternative food sources extending N. tutae longevity and enhancing the fitness of its offspring. Our results provided evidence for the combination of bottom-up and top-down approaches in tomato integrated pest management programs. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  4. Influence of jet thrust on penetrator penetration when studying the structure of space object blanket

    Directory of Open Access Journals (Sweden)

    N. A. Fedorova

    2014-01-01

    interaction between the penetrator and the soil within the range of 250 and 1500 m/s with Tsiolkovsky number from 0.1 to 0.5. Obtained results show that there are optimal times when the jet thrust engine "switches on" and operates, thus providing a maximum increase in penetration depth. This time optimum is due to two competitive factors associated with the reactive projectile penetration. On the one hand, there is an additional reactive force that contributes to penetration depth increase. On the other one, due to fuel combustion, the penetrator mass decreases, thereby leading to its reduced penetration capability.It was shown that a value of Tsiolkovsky number has a significant influence on the motion of penetrator using a jet engine. With raising Z, a penetration depth increases as well. At initial velocity of 500 m/s and optimal time parameters of reactive pulse, penetration depth increases almost by 40% for Z = 0,1, 90 % for Z = 0,25, and 2.5 times for Z = 0,5. As initial velocity of the penetrator grows, effectiveness of additional reactive acceleration significantly decreases. This is due to decreased relative portion of chemical energy of rocket propellant combustion as compared to the initial kinetic energy of penetrator with its reducing velocity.A conclusion based on research results was drawn up that a penetrator module under examination equipped with the pulse jet engine is an efficient facility for the significant increase of penetration depth in low-strength soil targets. It was emphasized that the maximum increase in penetration depth was reached when a running jet engine makes the penetrator to move in the target rather than at its prestart (before coming in contact with the target.

  5. Equilibrium isotope effects on noncovalent interactions in a supramolecular host-guest system.

    Science.gov (United States)

    Mugridge, Jeffrey S; Bergman, Robert G; Raymond, Kenneth N

    2012-02-01

    The self-assembled supramolecular complex [Ga(4)L(6)](12-) (1; L = 1,5-bis[2,3-dihydroxybenzamido]naphthalene) can act as a molecular host in aqueous solution and bind cationic guest molecules to its highly charged exterior surface or within its hydrophobic interior cavity. The distinct internal cavity of host 1 modifies the physical properties and reactivity of bound guest molecules and can be used to catalyze a variety of chemical transformations. Noncovalent host-guest interactions in large part control guest binding, molecular recognition and the chemical reactivity of bound guests. Herein we examine equilibrium isotope effects (EIEs) on both exterior and interior guest binding to host 1 and use these effects to probe the details of noncovalent host-guest interactions. For both interior and exterior binding of a benzylphosphonium guest in aqueous solution, protiated guests are found to bind more strongly to host 1 (K(H)/K(D) > 1) and the preferred association of protiated guests is driven by enthalpy and opposed by entropy. Deuteration of guest methyl and benzyl C-H bonds results in a larger EIE than deuteration of guest aromatic C-H bonds. The observed EIEs can be well explained by considering changes in guest vibrational force constants and zero-point energies. DFT calculations further confirm the origins of these EIEs and suggest that changes in low-frequency guest C-H/D vibrational motions (bends, wags, etc.) are primarily responsible for the observed EIEs. © 2011 American Chemical Society

  6. Penetration of Milk-Derived Antimicrobial Peptides into Phospholipid Monolayers as Model Biomembranes

    Science.gov (United States)

    Rogalska, Ewa; Więcław-Czapla, Katarzyna

    2013-01-01

    Three antimicrobial peptides derived from bovine milk proteins were examined with regard to penetration into insoluble monolayers formed with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DPPG). Effects on surface pressure (Π) and electric surface potential (ΔV) were measured, Π with a platinum Wilhelmy plate and ΔV with a vibrating plate. The penetration measurements were performed under stationary diffusion conditions and upon the compression of the monolayers. The two type measurements showed greatly different effects of the peptide-lipid interactions. Results of the stationary penetration show that the peptide interactions with DPPC monolayer are weak, repulsive, and nonspecific while the interactions with DPPG monolayer are significant, attractive, and specific. These results are in accord with the fact that antimicrobial peptides disrupt bacteria membranes (negative) while no significant effect on the host membranes (neutral) is observed. No such discrimination was revealed from the compression isotherms. The latter indicate that squeezing the penetrant out of the monolayer upon compression does not allow for establishing the penetration equilibrium, so the monolayer remains supersaturated with the penetrant and shows an under-equilibrium orientation within the entire compression range, practically. PMID:24455264

  7. Ethical hacking and penetration testing guide

    CERN Document Server

    Baloch, Rafay

    2014-01-01

    Requiring no prior hacking experience, Ethical Hacking and Penetration Testing Guide supplies a complete introduction to the steps required to complete a penetration test, or ethical hack, from beginning to end. You will learn how to properly utilize and interpret the results of modern-day hacking tools, which are required to complete a penetration test. The book covers a wide range of tools, including Backtrack Linux, Google reconnaissance, MetaGooFil, dig, Nmap, Nessus, Metasploit, Fast Track Autopwn, Netcat, and Hacker Defender rootkit. Supplying a simple and clean explanation of how to effectively utilize these tools, it details a four-step methodology for conducting an effective penetration test or hack.Providing an accessible introduction to penetration testing and hacking, the book supplies you with a fundamental understanding of offensive security. After completing the book you will be prepared to take on in-depth and advanced topics in hacking and penetration testing. The book walks you through each ...

  8. Prevention of follicular penetration: barrier-enhancing formulations against the penetration of pollen allergens into hair follicles.

    Science.gov (United States)

    Meinke, M C; Patzelt, A; Richter, H; Schanzer, S; Sterry, W; Filbry, A; Bohnsack, K; Rippke, F; Galecka, J; Fölster-Holst, R; Lademann, J

    2011-01-01

    The hair follicles could be a reservoir for topically applied substances. They are not only surrounded by a close network of blood capillaries, which makes them interesting for drug delivery, but they are also the host of dendritic cells, which are important for immunomodulation. Previously, pollen allergens were shown to penetrate into the hair follicles. The application of barrier-enhancing formulations might represent an effective strategy to prevent pollen protein penetration into the hair follicle. In the present study, porcine skin areas were pretreated with 4 barrier-enhancing emulsions. One skin area served as control and remained without pretreatment. Afterwards, fluorescein-isothiocyanate-labeled grass pollen proteins were applied to the porcine skin samples, and their penetration was investigated via fluorescent laser scanning microscopy. It was shown that the barrier-enhancing formulations were able to significantly reduce the penetration of exogenous proteins into the hair follicles, the extent of such reduction depending on the formulation. Copyright © 2011 S. Karger AG, Basel.

  9. Lack of effect of selected sunscreens applied on ex vivo human skin for 5-methyl-aminolevulinic acid penetration and protoporphyrin IX photoactivation.

    Science.gov (United States)

    Osman-Ponchet, Hanan; Sevin, Karine; Gaborit, Alexandre; Kouidhi, Magali; Hanaizi, Johanna; Comby, Pierre; Ruty, Bernard; Bouvier, Guy

    2017-03-01

    Photodynamic therapy (PDT) is a successful treatment for non-melanoma skin cancers. Methyl-aminolevulinate (MAL) is metabolized to protoporphyrin IX (PpIX) which accumulates in the skin lesion and which generates a painful photochemical toxic reaction upon red light exposure. PDT using daylight (DL) exposure is now used to reduce pain and subjects are advised to protect the areas with sunscreen. This work investigated the effect of sunscreen on MAL penetration and PpIX photoactivation in ex vivo human skin. To measure skin penetration of MAL, particle-free sunscreens were applied on ex vivo human skin samples mounted on diffusion cells before application of Metvix cream containing [14C]-MAL for 2.5h. To circumvent the absence of skin penetration of PpIX, skin samples were first treated with microneedles and mounted on diffusion cells before the application of PpIX solution for 1h followed by sunscreens. Skin samples were then exposed to solar simulator for 1h. Concentrations of [14C]-MAL or PpIX were measured in both total skin and receptor liquid. The results showed that the in vitro skin penetration of MAL and the PpIX photoactivation on ex vivo human skin samples are not modified by pretreatments of ex vivo human skin with sunscreens. This study demonstrates that neither in vitro skin penetration of MAL nor PpIX photoactivation were modified by pretreatments with Cetaphil SPF 30 Dermacontrol and Actinica® Lotion SPF 50+. This supports the efficacy and safety of MAL DL-PDT in the clinical situation. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  10. The Impact of IPv6 on Penetration Testing

    NARCIS (Netherlands)

    Ottow, Christiaan; van Vliet, Frank; de Boer, Pieter-Tjerk; Pras, Aiko

    In this paper we discuss the impact the use of IPv6 has on remote penetration testing of servers and web applications. Several modifications to the penetration testing process are proposed to accommodate IPv6. Among these modifications are ways of performing fragmentation attacks, host discovery and

  11. Penetrating Thoracic Injury.

    Science.gov (United States)

    Durso, Anthony M; Caban, Kim; Munera, Felipe

    2015-07-01

    This article discusses the role of radiology in evaluating patients with penetrating injuries to the chest. Penetrating injuries to the chest encompass ballistic and nonballistic injuries and can involve superficial soft tissues of the chest wall, lungs and pleura, diaphragm, and mediastinum. The mechanism of injury in ballistic and nonballistic trauma and the impact the injury trajectory has on imaging evaluation of penetrating injuries to the chest are discussed. The article presents the broad spectrum of imaging findings a radiologist encounters with penetrating injuries to the chest, with emphasis on injuries to the lungs and pleura, diaphragm, and mediastinum. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Invasion, persistence and control in epidemic models for plant pathogens: the effect of host demography.

    Science.gov (United States)

    Cunniffe, Nik J; Gilligan, Christopher A

    2010-03-06

    Many epidemiological models for plant disease include host demography to describe changes in the availability of susceptible tissue for infection. We compare the effects of using two commonly used formulations for host growth, one linear and the other nonlinear, upon the outcomes for invasion, persistence and control of pathogens in a widely used, generic model for botanical epidemics. The criterion for invasion, reflected in the basic reproductive number, R(0), is unaffected by host demography: R(0) is simply a function of epidemiological parameters alone. When, however, host growth is intrinsically nonlinear, unexpected results arise for persistence and the control of disease. The endemic level of infection (I(infinity)) also depends upon R(0). We show, however, that the sensitivity of I(infinity) to changes in R(0) > 1 depends upon which underlying epidemiological parameter is changed. Increasing R(0) by shortening the infectious period results in a monotonic increase in I(infinity). If, however, an increase in R(0) is driven by increases in transmission rates or by decreases in the decay of free-living inoculum, I(infinity) first increases (R(0) 2). This counterintuitive result means that increasing the intensity of control can result in more endemic infection.

  13. The lyme disease pathogen has no effect on the survival of its rodent reservoir host.

    Directory of Open Access Journals (Sweden)

    Maarten J Voordouw

    Full Text Available Zoonotic pathogens that cause devastating morbidity and mortality in humans may be relatively harmless in their natural reservoir hosts. The tick-borne bacterium Borrelia burgdorferi causes Lyme disease in humans but few studies have investigated whether this pathogen reduces the fitness of its reservoir hosts under natural conditions. We analyzed four years of capture-mark-recapture (CMR data on a population of white-footed mice, Peromyscus leucopus, to test whether B. burgdorferi and its tick vector affect the survival of this important reservoir host. We used a multi-state CMR approach to model mouse survival and mouse infection rates as a function of a variety of ecologically relevant explanatory factors. We found no effect of B. burgdorferi infection or tick burden on the survival of P. leucopus. Our estimates of the probability of infection varied by an order of magnitude (0.051 to 0.535 and were consistent with our understanding of Lyme disease in the Northeastern United States. B. burgdorferi establishes a chronic avirulent infection in their rodent reservoir hosts because this pathogen depends on rodent mobility to achieve transmission to its sedentary tick vector. The estimates of B. burgdorferi infection risk will facilitate future theoretical studies on the epidemiology of Lyme disease.

  14. Effects of environmental variation on host-parasite interaction in three-spined sticklebacks (Gasterosteus aculeatus).

    Science.gov (United States)

    Scharsack, Jörn P; Franke, Frederik; Erin, Noémi I; Kuske, Andra; Büscher, Janine; Stolz, Hendrik; Samonte, Irene E; Kurtz, Joachim; Kalbe, Martin

    2016-08-01

    Recent research provides accumulating evidence that the evolutionary dynamics of host-parasite adaptations strongly depend on environmental variation. In this context, the three-spined stickleback (Gasterosteus aculeatus) has become an important research model since it is distributed all over the northern hemisphere and lives in very different habitat types, ranging from marine to freshwater, were it is exposed to a huge diversity of parasites. While a majority of studies start from explorations of sticklebacks in the wild, only relatively few investigations have continued under laboratory conditions. Accordingly, it has often been described that sticklebacks differ in parasite burden between habitats, but the underlying co-evolutionary trajectories are often not well understood. With the present review, we give an overview of the most striking examples of stickleback-parasite-environment interactions discovered in the wild and discuss two model parasites which have received some attention in laboratory studies: the eye fluke Diplostomum pseudospathacaeum, for which host fish show habitat-specific levels of resistance, and the tapeworm Schistocephalus solidus, which manipulates immunity and behavior of its stickleback host to its advantage. Finally, we will concentrate on an important environmental variable, namely temperature, which has prominent effects on the activity of the immune system of ectothermic hosts and on parasite growth rates. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

  15. The effects of host obscuration on searches for tidal disruption events

    Science.gov (United States)

    Roth, Nathaniel; Mushotzky, Richard; Gezari, Suvi; van Velzen, Sjoert

    2018-01-01

    Tidal disruptions of stars by super-massive black holes (TDEs) offer opportunities to learn about black hole demographics and stellar dynamics. However, matching the observed TDE rate to that predicted by theory has remained a challenge, as most surveys to-date have found fewer flares than expected. Some of this discrepancy may relate to nuclear obscuration in host galaxies. This includes the effects of dust at optical and ultraviolet wavelengths, and the effects of neutral gas at x-ray wavelengths. I will discuss procedures to correct the observed TDE rate within existing and upcoming surveys to the intrinsic per-galaxy rate by accounting for host obscuration. I will also discuss how reddening might affect TDE selection criteria, and I will make predictions for the population of infrared TDE light echoes.

  16. Trypanosoma cruzi: effect of phenothiazines on the parasite and its interaction with host cells

    Directory of Open Access Journals (Sweden)

    Solange L. de Castro

    1992-06-01

    Full Text Available Phenothiazines were observed to have a direct effect on Trypanosoma cruzi and on its in vitro interaction with host cells. They caused lysis of trypomastigotes (50 uM/24 h and,to a lesser extent, epimastigote proliferation. Treatment of infected peritoneal macrophages with 12.5 uM chlorpromazine or triflupromazine inhibited the infection; this effect was found to be partially reversible if the drugs were removed after 24 h of treatment. At 60 uM, the drugs caused damage to amastigotes interiorized in heart muscle cells. However, the narrow margin of toxity between anti-trypanossomal activity and damage to host cells mitigates against in vivo investigation at the present time. Possible hypothesis for the mechanism of action of phenothiazines are discussed.

  17. Effects of simulated rain acidified with sulfuric acid on host-parasite interactions

    Science.gov (United States)

    D. S. Shriner

    1976-01-01

    Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The effects of simulated rain acidified with sulfuric acid were studied on several host-parasite systems. Plants were exposed, in greenhouse or field, to simulated rain of pH 3.2 ? 0.1 or pH 6.0 ? 0.2. Simulated "rain" of pH 3.2 resulted...

  18. Effect of varying lanthanide local coordination sphere on luminescence properties illustrated by selected inorganic and organic rare earth complexes synthesized in sol-gel host glasses

    Energy Technology Data Exchange (ETDEWEB)

    Zaitoun, M.A., E-mail: zaitoun444@yahoo.com [Department of Chemistry, Mutah University, P.O Box. 7, Karak (Jordan); Al-Tarawneh, S. [Department of Chemistry, Mutah University, P.O Box. 7, Karak (Jordan)

    2011-08-15

    Inorganic and organic ligands were carefully selected to illustrate the effect of modifications in the local field environment around the rare earth lanthanide (III) on its emission properties. In this article two strategies were employed to enhance emission of lanthanides encapsulated in sol-gel glass. (i) Changing the symmetry around the lanthanide, which was diagnosed by changing the local environment around the lanthanide using different inorganic counter ions (acetate, nitrate and chloride) these ligands differ in their affinity toward the lanthanide first coordination sphere. The ligand that penetrates the lanthanide more results in more asymmetric environment and thus results in higher emission. The aim of this part was to demonstrate the change of symmetry on emission in the absence of energy transfer. Our results indicate that the acetate ion has the highest affinity toward the first coordination sphere followed by the nitrate while the chloride showed the lowest affinity. Penetration by the ligands ofthe lanthanide also results in removing OH quenchers surrounding the lanthanide and this further explains the boost in emission. (ii) A bulky organic ligand that forms a complex with the lanthanide is used. The organic ligand separates the lanthanide ion from inner O-H oscillators. In this case the chelating organic chromophore with suitable photophysical properties was employed to sensitize the lanthanide and thus energy transfer occurs via the antenna effect. The organic ligand absorbs UV light, then energy is transferred to the lanthanide and finally the lanthanide emits in the visible region. The first coordination environment surrounding europium was controlled by the ligand selection and the outer sphere was modified by doping the synthesized complexes in an optically transparent sol-gel glass host. The glass network carefully prepared by sol-gel process is effective in preventing free oxygen and water from attacking lanthanide -complexes without loss

  19. The effect of heritability and host genetics on the gut microbiota and metabolic syndrome.

    Science.gov (United States)

    Lim, Mi Young; You, Hyun Ju; Yoon, Hyo Shin; Kwon, Bomi; Lee, Jae Yoon; Lee, Sunghee; Song, Yun-Mi; Lee, Kayoung; Sung, Joohon; Ko, GwangPyo

    2017-06-01

    Metabolic syndrome (MetS) arises from complex interactions between host genetic and environmental factors. Although it is now widely accepted that the gut microbiota plays a crucial role in host metabolism, current knowledge on the effect of host genetics on specific gut microbes related to MetS status remains limited. Here, we investigated the links among host genetic factors, gut microbiota and MetS in humans. We characterised the gut microbial community composition of 655 monozygotic (n=306) and dizygotic (n=74) twins and their families (n=275), of which approximately 18% (121 individuals) had MetS. We evaluated the association of MetS status with the gut microbiota and estimated the heritability of each taxon. For the MetS-related and heritable taxa, we further investigated their associations with the apolipoprotein A-V gene ( APOA5 ) single nucleotide polymorphism (SNP) rs651821, which is known to be associated with triglyceride levels and MetS. Individuals with MetS had a lower gut microbiota diversity than healthy individuals. The abundances of several taxa were associated with MetS status; Sutterella , Methanobrevibacter and Lactobacillus were enriched in the MetS group, whereas Akkermansia , Odoribacter and Bifidobacterium were enriched in the healthy group. Among the taxa associated with MetS status, the phylum Actinobacteria, to which Bifidobacterium belongs, had the highest heritability (45.7%). Even after adjustment for MetS status, reduced abundances of Actinobacteria and Bifidobacterium were significantly linked to the minor allele at the APOA5 SNP rs651821. Our results suggest that an altered microbiota composition mediated by a specific host genotype can contribute to the development of MetS. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  20. Effects of Host Phylogeny and Habitats on Gut Microbiomes of Oriental River Prawn (Macrobrachium nipponense.

    Directory of Open Access Journals (Sweden)

    Tzong-Der Tzeng

    Full Text Available The gut microbial community is one of the richest and most complex ecosystems on earth, and the intestinal microbes play an important role in host development and health. Next generation sequencing approaches, which rapidly produce millions of short reads that enable the investigation on a culture independent basis, are now popular for exploring microbial community. Currently, the gut microbiome in fresh water shrimp is unexplored. To explore gut microbiomes of the oriental river prawn (Macrobrachium nipponense and investigate the effects of host genetics and habitats on the microbial composition, 454 pyrosequencing based on the 16S rRNA gene were performed. We collected six groups of samples, including M. nipponense shrimp from two populations, rivers and lakes, and one sister species (M. asperulum as an out group. We found that Proteobacteria is the major phylum in oriental river prawn, followed by Firmicutes and Actinobacteria. Compositional analysis showed microbial divergence between the two shrimp species is higher than that between the two populations of one shrimp species collected from river and lake. Hierarchical clustering also showed that host genetics had a greater impact on the divergence of gut microbiome than host habitats. This finding was also congruent with the functional prediction from the metagenomic data implying that the two shrimp species still shared the same type of biological functions, reflecting a similar metabolic profile in their gut environments. In conclusion, this study provides the first investigation of the gut microbiome of fresh water shrimp, and supports the hypothesis of host species-specific signatures of bacterial community composition.

  1. Effects of maternal diet and host quality on oviposition patterns and offspring performance in a seed beetle (Coleoptera: Bruchidae)

    Science.gov (United States)

    González-Teuber, Marcia; Segovia, Ricardo; Gianoli, Ernesto

    2008-07-01

    In seed beetles, oviposition decisions may influence the offspring phenotype because eggs constitute the initial resources available for larval development. We tested the effects of host quality variations (small vs. large seeds of the host plant Calystegia sepium, Convolvulaceae) on oviposition patterns and offspring performance of the seed beetle Megacerus eulophus. We also manipulated the maternal diet: high diet quality vs. low diet quality to evaluate possible interactive effects of the maternal nutritional environment and host quality on oviposition patterns. We further assessed the consequences of egg size variation in offspring size. Female M. eulophus fed with high-quality diet (H-diet) laid more eggs and lived longer than females fed with low-quality diet (P-diet). Fecundity decreased under a low-quality host for both maternal diets. The occurrence of maternal environmental effects on egg size plasticity was detected. Under conditions of low-quality host, mothers fed with the high-quality diet produced bigger eggs in comparison with a high-quality host, whereas females fed with the low-quality diet produced smaller ones. Regardless of these differences observed in egg size depending on the maternal diet, progeny emerging from small seeds (low-quality host) showed a similar performance at emergence. Offspring traits were only significantly affected by host quality. Beetles emerging from large seeds had greater body weight and length than those reared on small seeds. Variations in oviposition patterns in response to host quality are discussed.

  2. Effect of bacterial and host factors on Helicobacter pylori eradication therapy.

    Science.gov (United States)

    Uotani, Takahiro; Miftahussurur, Muhammad; Yamaoka, Yoshio

    2015-01-01

    A clearer understanding of the factors affecting the cure rate of Helicobacter pylori infection might lead to the development of novel prevention strategies and therapeutic targets. This review covers two important issues that affect the eradication of H. pylori: bacterial and host factors. Several virulence factors have been shown to be predictors for gastroduodenal diseases. Successful treatment of H. pylori infection also depends on host genetic factors such as CYP2C19 and IL-1B. The latest evidence on host genetic factors is discussed. The authors identify three main targets for achieving effective eradication therapy. The first therapeutic target is to identify counter measures for antibiotic-resistant H. pylori strains. Thus, antibiotic susceptibility should be checked in all patients, ideally, before the start of eradication treatment. The second therapeutic target is the inhibition of acid suppression. Maintaining a high intragastric pH for 24 h increases the effectiveness of some antibiotics and the eradication effects for H. pylori. The third therapeutic target is to identify high-risk groups; the CYP2C19 and IL-1B polymorphisms are candidates for significant risk factors. A personalized medical approach will likely increase the cure rate of H. pylori infection.

  3. The effect of host cluster gravitational tidal forces on the internal dynamics of spiral galaxies

    Science.gov (United States)

    Mayer, Alexander

    2013-04-01

    New empirical observation by Bidin, Carraro, Mendez & Smith finds ``a lack of dark matter in the Solar neighborhood" (2012 ApJ 751, 30). This, and the discovery of a vast polar structure of Milky Way satellites by Pawlowski, Pflamm-Altenburg & Kroupa (2012 MNRAS 423, 1109), conflict with the prevailing interpretation of the measured Galactic rotation curve. Simulating the dynamical effects of host cluster tidal forces on galaxy disks reveals radial migration in a spiral structure and an orbital velocity that accelerates with increasing galactocentric radial coordinate. A virtual ``toy model,'' which is based on an Earth-orbiting system of particles and is physically realizable in principle, is available at GravitySim.net. Given the perturbing gravitational effect of the host cluster on a spiral galaxy disk and that a similar effect does not exist for the Solar System, the two systems represent distinct classes of gravitational dynamical systems. The observed `flat' and accelerating rotation curves of spiral galaxies can be attributed to gravitational interaction with the host cluster; no `dark matter halo' is required to explain the observable.

  4. Endomorphin-1 analogues (MELs) penetrate the blood-brain barrier and exhibit good analgesic effects with minimal side effects.

    Science.gov (United States)

    Wang, Yuan; Liu, Xin; Wang, Dan; Yang, Junxian; Zhao, Long; Yu, Jing; Wang, Rui

    2015-10-01

    Endomorphins are endogenous opioid peptides in mammals and display a strong antinociceptive effect after central administration. However, the clinical usage of these peptides is limited because of their diminished analgesic effect following systemic injection and their inability to cross the blood-brain barrier. In this study, we characterized the in vivo effects of four novel endomorphin-1 analogues (termed MELs), which previously showed potential as highly potent analgesics with a good pharmacological profile in vitro. The analogues were administered intravenously to several rodent pain models to examine their antinociception and blood-brain barrier permeability. The tested peptides, especially MEL1214, showed good analgesic activity and blood-brain barrier permeability. Behavioral studies showed dose-dependent analgesic effect after systematic administration of MEL1214 in the tested pain models. Pre-treatment of subcutaneous administration of naloxone methiodide did not affect the antinociception of these peptides. As compared to morphine, MEL1214 was less prone to induce tolerance after consecutive intravenous administration for 5 days. Gastrointestinal transit was evaluated by the isolated colon response and bead expulsion to determine the potential constipation effect. In contrast to morphine, MEL1214 produced no significant constipation effect at an equivalent dose. MEL1214 shows promise as a suitable compound to treat pain with reduced side effects, and exhibits good potential to be further developed as a novel opioid analgesic in pain treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Effect of lactoferrin protein on red blood cells and macrophages: mechanism of parasite-host interaction.

    Science.gov (United States)

    Anand, Namrata; Kanwar, Rupinder K; Dubey, Mohan Lal; Vahishta, R K; Sehgal, Rakesh; Verma, Anita K; Kanwar, Jagat R

    2015-01-01

    Lactoferrin is a natural multifunctional protein known to have antitumor, antimicrobial, and anti-inflammatory activity. Apart from its antimicrobial effects, lactoferrin is known to boost the immune response by enhancing antioxidants. Lactoferrin exists in various forms depending on its iron saturation. The present study was done to observe the effect of lactoferrin, isolated from bovine and buffalo colostrum, on red blood cells (RBCs) and macrophages (human monocytic cell line-derived macrophages THP1 cells). Lactoferrin obtained from both species and in different iron saturation forms were used in the present study, and treatment of host cells were given with different forms of lactoferrin at different concentrations. These treated host cells were used for various studies, including morphometric analysis, viability by MTT assay, survivin gene expression, production of reactive oxygen species, phagocytic properties, invasion assay, and Toll-like receptor-4, Toll-like receptor-9, and MDR1 expression, to investigate the interaction between lactoferrin and host cells and the possible mechanism of action with regard to parasitic infections. The mechanism of interaction between host cells and lactoferrin have shown various aspects of gene expression and cellular activity depending on the degree of iron saturation of lactoferrin. A significant increase (Plactoferrin when compared with an untreated control group. However, there was no significant (P>0.05) change in percentage viability in the different groups of host cells treated, and no downregulation of survivin gene expression was found at 48 hours post-incubation. Upregulation of the Toll-like receptor and downregulation of the P-gp gene confirmed the immunomodulatory potential of lactoferrin protein. The present study details the interaction between lactoferrin and parasite host cells, ie, RBCs and macrophages, using various cellular processes and expression studies. The study reveals the possible mechanism of

  6. Effect of lactoferrin protein on red blood cells and macrophages: mechanism of parasite–host interaction

    Science.gov (United States)

    Anand, Namrata; Kanwar, Rupinder K; Dubey, Mohan Lal; Vahishta, R K; Sehgal, Rakesh; Verma, Anita K; Kanwar, Jagat R

    2015-01-01

    Background Lactoferrin is a natural multifunctional protein known to have antitumor, antimicrobial, and anti-inflammatory activity. Apart from its antimicrobial effects, lactoferrin is known to boost the immune response by enhancing antioxidants. Lactoferrin exists in various forms depending on its iron saturation. The present study was done to observe the effect of lactoferrin, isolated from bovine and buffalo colostrum, on red blood cells (RBCs) and macrophages (human monocytic cell line-derived macrophages THP1 cells). Methods Lactoferrin obtained from both species and in different iron saturation forms were used in the present study, and treatment of host cells were given with different forms of lactoferrin at different concentrations. These treated host cells were used for various studies, including morphometric analysis, viability by MTT assay, survivin gene expression, production of reactive oxygen species, phagocytic properties, invasion assay, and Toll-like receptor-4, Toll-like receptor-9, and MDR1 expression, to investigate the interaction between lactoferrin and host cells and the possible mechanism of action with regard to parasitic infections. Results The mechanism of interaction between host cells and lactoferrin have shown various aspects of gene expression and cellular activity depending on the degree of iron saturation of lactoferrin. A significant increase (Plactoferrin when compared with an untreated control group. However, there was no significant (P>0.05) change in percentage viability in the different groups of host cells treated, and no downregulation of survivin gene expression was found at 48 hours post-incubation. Upregulation of the Toll-like receptor and downregulation of the P-gp gene confirmed the immunomodulatory potential of lactoferrin protein. Conclusion The present study details the interaction between lactoferrin and parasite host cells, ie, RBCs and macrophages, using various cellular processes and expression studies. The study

  7. Curb Challenges of the “Trojan Horse” Approach: Smart Strategies in Achieving Effective yet Safe Cell-penetrating Peptide-based Drug Delivery

    Science.gov (United States)

    Huang, Yongzhuo; Jiang, Yifan; Wang, Huiyuan; Wang, Jianxin; Shin, Meong Cheol; Byun, Youngro; He, Huining; Liang, Yanqin; Yang, Victor C.

    2013-01-01

    Cell-penetrating peptide (CPP)-mediated intracellular drug delivery system, often specifically termed as “the Trojan horse approach”, has become the “holy grail” in achieving effective delivery of macromolecular compounds such as proteins, DNA, siRNAs, and drug carriers. It is characterized by the unique cell- (or receptor-), temperature-, and payload-independent mechanisms, therefore offering potent means to improve poor cellular uptake of a variety of macromolecular drugs. Nevertheless, this “Trojan horse” approach also acts like a double-edged sword, causing serious safety and toxicity concerns to normal tissues or organs for in vivo application, due to lack of target selectivity of the powerful cell penetrating activity. To overcome this problem of potent yet non-selective penetration vs. targeting delivery, a number of “smart” strategies have been developed in recent years, including controllable CPP-based drug delivery systems based on various stimuli-responsive mechanisms. This review article provides a fundamental understanding of these smart systems, as well as a discussion of their real-time in vivo applicability. PMID:23369828

  8. A preliminary assessment of the effects of heat flux distribution and penetration on the creep rupture of a reactor vessel lower head

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.Y.; Bentz, J.; Simpson, R. [Sandia National Labs., Albuquerque, NM (United States); Witt, R. [Univ. of Wisconsin, Madison, WI (United States)

    1997-02-01

    The objective of the Lower Head Failure (LHF) Experiment Program is to experimentally investigate and characterize the failure of the reactor vessel lower head due to thermal and pressure loads under severe accident conditions. The experiment is performed using 1/5-scale models of a typical PWR pressure vessel. Experiments are performed for various internal pressure and imposed heat flux distributions with and without instrumentation guide tube penetrations. The experimental program is complemented by a modest modeling program based on the application of vessel creep rupture codes developed in the TMI Vessel Investigation Project. The first three experiments under the LHF program investigated the creep rupture of simulated reactor pressure vessels without penetrations. The heat flux distributions for the three experiments are uniform (LHF-1), center-peaked (LHF-2), and side-peaked (LHF-3), respectively. For all the experiments, appreciable vessel deformation was observed to initiate at vessel wall temperatures above 900K and the vessel typically failed at approximately 1000K. The size of failure was always observed to be smaller than the heated region. For experiments with non-uniform heat flux distributions, failure typically occurs in the region of peak temperature. A brief discussion of the effect of penetration is also presented.

  9. Effect of technique of sealer agitation on percentage and depth of MTA Fillapex sealer penetration: A comparative in-vitro study

    Science.gov (United States)

    Nikhil, Vineeta; Bansal, Parul; Sawani, Shefali

    2015-01-01

    Aim: To compare the effect of three root canal sealer activation techniques on percentage and depth of sealer penetration of MTA Fillapex and AH Plus sealers. Materials and Methods: Sixty teeth prepared till F5 ProTaper size were divided into three equal groups on the basis of sealer activation technique (G1: Ultrasonics, G2: Lentulo spiral, and G3: Counter-clockwise rotary motion). Each group was further divided into two equal subgroups on the basis of type of sealer used: AH Plus (Denstply, Konstanz, Germany) or MTA Fillapex (Angelus, Londrina, PR, Brazil) and obturated with gutta-percha. Horizontal sections at 3 and 6 mm from the apex were obtained and the percentage and depth of penetration of sealers into dentinal tubules were measured using confocal laser scanning microscopy (CLSM). Statistical analysis was performed utilizing Kruskal-Wallis and Mann-Whitney U tests with a significance level of 5%. Results: G1 showed significantly (P 0.05) between G2 and G3. Conclusion: Percentage and depth of sealer penetration are influenced by the type of sealer used sealer activation technique and by the root canal level. Ultrasonic method of sealer activation and MTA Fillapex showed the best results. PMID:25829689

  10. Title: Investigating the effects of a penetrating vessel occlusion with a multi-scale microvasculature model of the human cerebral cortex.

    Science.gov (United States)

    El-Bouri, Wahbi K; Payne, Stephen J

    2018-01-19

    The effect of the microvasculature on observed clinical parameters, such as cerebral blood flow, is poorly understood. This is partly due to the gap between the vessels that can be individually imaged in humans and the microvasculature, meaning that mathematical models are required to understand the role of the microvasculature. As a result, a multi-scale model based on morphological data was developed here that is able to model large regions of the human microvasculature. From this model, a clear layering of flow (and 1-dimensional depth profiles) was observed within a voxel, with the flow in the microvasculature being driven predominantly by the geometry of the penetrating vessels. It also appears that the pressure and flow are decoupled, both in healthy vasculatures and in those where occlusions have occurred, again due to the topology of the penetrating vessels shunting flow between them. Occlusion of a penetrating arteriole resulted in a very high degree of overlap of blood pressure drop with experimentally observed cell death. However, drops in blood flow were far more widespread, providing additional support for the theory that pericyte controlled regulation on the capillary scale likely plays a large part in the perfusion of tissue post-occlusion. Copyright © 2018. Published by Elsevier Inc.

  11. Curb challenges of the "Trojan Horse" approach: smart strategies in achieving effective yet safe cell-penetrating peptide-based drug delivery.

    Science.gov (United States)

    Huang, Yongzhuo; Jiang, Yifan; Wang, Huiyuan; Wang, Jianxin; Shin, Meong Cheol; Byun, Youngro; He, Huining; Liang, Yanqin; Yang, Victor C

    2013-10-01

    Cell-penetrating peptide (CPP)-mediated intracellular drug delivery system, often specifically termed as "the Trojan horse approach", has become the "holy grail" in achieving effective delivery of macromolecular compounds such as proteins, DNA, siRNAs, and drug carriers. It is characterized by the unique cell- (or receptor-), temperature-, and payload-independent mechanisms, therefore offering potent means to improve poor cellular uptake of a variety of macromolecular drugs. Nevertheless, this "Trojan horse" approach also acts like a double-edged sword, causing serious safety and toxicity concerns to normal tissues or organs for in vivo application, due to lack of target selectivity of the powerful cell penetrating activity. To overcome this problem of potent yet non-selective penetration vs. targeting delivery, a number of "smart" strategies have been developed in recent years, including controllable CPP-based drug delivery systems based on various stimuli-responsive mechanisms. This review article provides a fundamental understanding of these smart systems, as well as a discussion of their real-time in vivo applicability. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Pathogen- and Host-Directed Antileishmanial Effects Mediated by Polyhexanide (PHMB.

    Directory of Open Access Journals (Sweden)

    Rebuma Firdessa

    Full Text Available Cutaneous leishmaniasis (CL is a neglected tropical disease caused by protozoan parasites of the genus Leishmania. CL causes enormous suffering in many countries worldwide. There is no licensed vaccine against CL, and the chemotherapy options show limited efficacy and high toxicity. Localization of the parasites inside host cells is a barrier to most standard chemo- and immune-based interventions. Hence, novel drugs, which are safe, effective and readily accessible to third-world countries and/or drug delivery technologies for effective CL treatments are desperately needed.Here we evaluated the antileishmanial properties and delivery potential of polyhexamethylene biguanide (PHMB; polyhexanide, a widely used antimicrobial and wound antiseptic, in the Leishmania model. PHMB showed an inherent antileishmanial activity at submicromolar concentrations. Our data revealed that PHMB kills Leishmania major (L. major via a dual mechanism involving disruption of membrane integrity and selective chromosome condensation and damage. PHMB's DNA binding and host cell entry properties were further exploited to improve the delivery and immunomodulatory activities of unmethylated cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN. PHMB spontaneously bound CpG ODN, forming stable nanopolyplexes that enhanced uptake of CpG ODN, potentiated antimicrobial killing and reduced host cell toxicity of PHMB.Given its low cost and long history of safe topical use, PHMB holds promise as a drug for CL therapy and delivery vehicle for nucleic acid immunomodulators.

  13. Pathogen- and Host-Directed Antileishmanial Effects Mediated by Polyhexanide (PHMB).

    Science.gov (United States)

    Firdessa, Rebuma; Good, Liam; Amstalden, Maria Cecilia; Chindera, Kantaraja; Kamaruzzaman, Nor Fadhilah; Schultheis, Martina; Röger, Bianca; Hecht, Nina; Oelschlaeger, Tobias A; Meinel, Lorenz; Lühmann, Tessa; Moll, Heidrun

    2015-01-01

    Cutaneous leishmaniasis (CL) is a neglected tropical disease caused by protozoan parasites of the genus Leishmania. CL causes enormous suffering in many countries worldwide. There is no licensed vaccine against CL, and the chemotherapy options show limited efficacy and high toxicity. Localization of the parasites inside host cells is a barrier to most standard chemo- and immune-based interventions. Hence, novel drugs, which are safe, effective and readily accessible to third-world countries and/or drug delivery technologies for effective CL treatments are desperately needed. Here we evaluated the antileishmanial properties and delivery potential of polyhexamethylene biguanide (PHMB; polyhexanide), a widely used antimicrobial and wound antiseptic, in the Leishmania model. PHMB showed an inherent antileishmanial activity at submicromolar concentrations. Our data revealed that PHMB kills Leishmania major (L. major) via a dual mechanism involving disruption of membrane integrity and selective chromosome condensation and damage. PHMB's DNA binding and host cell entry properties were further exploited to improve the delivery and immunomodulatory activities of unmethylated cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN). PHMB spontaneously bound CpG ODN, forming stable nanopolyplexes that enhanced uptake of CpG ODN, potentiated antimicrobial killing and reduced host cell toxicity of PHMB. Given its low cost and long history of safe topical use, PHMB holds promise as a drug for CL therapy and delivery vehicle for nucleic acid immunomodulators.

  14. Simulated effects of host fish distribution on juvenile unionid mussel dispersal in a large river

    Science.gov (United States)

    Daraio, J.A.; Weber, L.J.; Zigler, S.J.; Newton, T.J.; Nestler, J.M.

    2012-01-01

    Larval mussels (Family Unionidae) are obligate parasites on fish, and after excystment from their host, as juveniles, they are transported with flow. We know relatively little about the mechanisms that affect dispersal and subsequent settlement of juvenile mussels in large rivers. We used a three-dimensional hydrodynamic model of a reach of the Upper Mississippi River with stochastic Lagrangian particle tracking to simulate juvenile dispersal. Sensitivity analyses were used to determine the importance of excystment location in two-dimensional space (lateral and longitudinal) and to assess the effects of vertical location (depth in the water column) on dispersal distances and juvenile settling distributions. In our simulations, greater than 50% of juveniles mussels settled on the river bottom within 500 m of their point of excystment, regardless of the vertical location of the fish in the water column. Dispersal distances were most variable in environments with higher velocity and high gradients in velocity, such as along channel margins, near the channel bed, or where effects of river bed morphology caused large changes in hydraulics. Dispersal distance was greater and variance was greater when juvenile excystment occurred in areas where vertical velocity (w) was positive (indicating an upward velocity) than when w was negative. Juvenile dispersal distance is likely to be more variable for mussels species whose hosts inhabit areas with steeper velocity gradients (e.g. channel margins) than a host that generally inhabits low-flow environments (e.g. impounded areas).

  15. Metasploit penetration testing cookbook

    CERN Document Server

    Agarwal, Monika

    2013-01-01

    This book follows a Cookbook style with recipes explaining the steps for penetration testing with WLAN, VOIP, and even cloud computing. There is plenty of code and commands used to make your learning curve easy and quick.This book targets both professional penetration testers as well as new users of Metasploit, who wish to gain expertise over the framework and learn an additional skill of penetration testing, not limited to a particular OS. The book requires basic knowledge of scanning, exploitation, and the Ruby language.

  16. Endophyte isolate and host grass effects on Chaetocnema pulicaria (Coleoptera: Chrysomelidae) feeding.

    Science.gov (United States)

    Ball, Olivier J P; Gwinn, Kimberly D; Pless, Charles D; Popay, Alison J

    2011-04-01

    Endophytic fungi belonging to the genus Neotyphodium, confer resistance to infected host grasses against insect pests. The effect of host species, and endophtye species and strain, on feeding and survival of the corn flea beetle, Chaetocnema pulicaria Melsheimer (Coleoptera: Chrysomelidae) was investigated. The grass-endophyte associations included natural and artificially derived associations producing varying arrays of common endophyte-related alkaloids or alkaloid groups, peramine, lolitrem B, ergovaline, and the lolines. Preference and nonpreference tests showed that C. pulicaria feeding and survival were reduced by infection of tall fescue with the wild-type strain of N. coenophialum, the likely mechanism being antixenosis rather than antibiosis. In the preference tests, endophyte and host species effects were observed. Of the 10 different Neotyphodium strains tested in artificially derived tall fescue associations, eight strongly deterred feeding by C. pulicaria, whereas the remaining two strains had little or no effect on feeding. Infection of tall fescue with another fungal symbiont, p-endophyte, had no effect. Perennial ryegrass, Lolium perenne L., infected with six strains of endophyte, was moderately resistant to C. pulicaria compared with endophyte-free grass, but four additional strains were relatively inactive. Six Neotyphodium-meadow fescue, Festuca pratensis Huds., associations, including the wild-type N. uncinatum-meadow fescue combination, were resistant, whereas three associations were not effective. Loline alkaloids seemed to play a role in antixenosis to C. pulicaria. Effects not attributable to the lolines or any other of the alkaloids examined also were observed. This phenomenon also has been reported in tests with other insects, and indicates the presence of additional insect-active factors.

  17. Investigations on THM effects in buffer, EDZ and argillaceous host rock. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jobmann, M.; Breustedt, M.; Li, S.; Polster, M.; Schirmer, S.

    2013-11-15

    especially valid for the most reactive rock components, which are the fine grained clay matrix and the organic components. A high amount of organic compounds is characteristic for clay formations. If the thermal maturation is advanced, an additional artificial heating over longer periods of time may have the effect that the limit where oil generation starts is exceeded. It is still to be clarified whether the heat input from the waste canisters is so high that this limit is exceeded and that oil in an amount worth extracting is generated. Depending on the pressure and temperature conditions, a mineral transformation or the formation of new minerals may occur, which would change the chemical and mineralogical conditions. Artificial heating could accelerate transformation processes and change the retardation properties of the host rock. Currently, there is no information available about the potential changes of the host rock properties due to the specific heat input of a repository in a clay formation in Germany. One important task to be performed with regard to the German safety requirements is the demonstration of the integrity of the geotechnical barriers and of the geological barrier. The only way to demonstrate the long-term integrity of the geological barrier is to carry out predictive calculations. These kinds of calculations must have a sound basis of rock-specific constitutive laws together with a well calibrated parameter set that represent the real physical host rock behaviour. To identify suitable constitutive laws and corresponding parameters, insitu experiments are being performed in the Mt. Terri and Meuse/Haute-Marne URLs in Switzerland and France. These experiments are well equipped with sensing systems that allow a comparison of measured and simulated results for rock parameter identification and corresponding model calibration.

  18. The host with the most? The effects of the Olympic Games on happiness

    OpenAIRE

    Dolan, Paul; Kavetsos, Georgios; Krekel, Christian; Mavridis, Dimitris; Metcalfe, Robert M.; Senik-Leygonie, Claudia; Szymanski, Stefan; Ziebarth, Nicolas

    2016-01-01

    We show that hosting the Olympic Games in 2012 had a positive impact on the life satisfaction and happiness of Londoners during the Games, compared to residents of Paris and Berlin. Notwithstanding issues of causal inference, the magnitude of the effects is equivalent to moving from the bottom to the fourth income decile. But they do not last very long: the effects are gone within a year. These conclusions are based on a novel panel survey of 26,000 individuals who were interviewed during the...

  19. Fluorescent Penetration Enhancers for Transdermal Applications

    Science.gov (United States)

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

    2011-01-01

    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 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 skin. PMID:22062691

  20. Impact of Renewable Energy Sources Penetration in a Microgrid

    National Research Council Canada - National Science Library

    N. Ravi; Y. Sumanth

    2014-01-01

    ... (Renewable Energy Sources) penetration in grid connected and islanded operation, and also shows the effect of wind and solar penetration individually and as well as coupled along with backup protection...

  1. Penetration testing with Perl

    CERN Document Server

    Berdeaux, Douglas

    2014-01-01

    If you are an expert Perl programmer interested in penetration testing or information security, this guide is designed for you. However, it will also be helpful for you even if you have little or no Linux shell experience.

  2. Proteases of Sporothrix schenckii: Cytopathological effects on a host-cell model.

    Science.gov (United States)

    Sabanero López, Myrna; Flores Villavicencio, Lérida L; Soto Arredondo, Karla; Barbosa Sabanero, Gloria; Villagómez-Castro, Julio César; Cruz Jiménez, Gustavo; Sandoval Bernal, Gerardo; Torres Guerrero, Haydee

    Sporotrichosis is a fungal infection caused by the Sporothrix schenckii complex. The adhesion of the fungus to the host tissue has been considered the key step in the colonization and invasion, but little is known about the early events in the host-parasite interaction. To evaluate the proteolytic activity of S. schenckii on epithelial cells. The proteolytic system (at pH 5 and 7) was evaluated using azocoll and zymograms. The host-parasite interaction and epithelial cell response were also analyzed by examining the microfilament cytoskeleton using phalloidin-FITC and transmission electron microscopy. Finally, the metabolic activity was determined using an XTT assay. The zymograms showed that S. schenckii yeast cells possess high intracellular and extracellular proteolytic activities (Mr≥200, 116, 97, and 70kDa) that are pH dependent and are inhibited by PMSF and E64, which act on serine and cysteine-type proteases. During the epithelial cell-protease interaction, the cells showed alterations in the microfilament distribution, as well as in the plasma membrane structure. Moreover, the metabolic activity of the epithelial cells decreased 60% without a protease inhibitor. Our data demonstrate the complexity of the cellular responses during the infection process. This process is somehow counteracted by the action of proteases inhibitors. Furthermore, the results provide critical information for understanding the nature of host-fungus interactions and for searching a new effective antifungal therapy, which includes protease inhibitors. Copyright © 2017 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. The direct effects of male killer infection on fitness of ladybird hosts (Coleoptera: Coccinellidae).

    Science.gov (United States)

    Elnagdy, S; Majerus, M E N; Gardener, M; Lawson Handley, L-J

    2013-08-01

    Male killing bacteria are common in insects and are thought to persist in host populations primarily by indirect fitness benefits to infected females, whereas direct fitness effects are generally assumed to be neutral or deleterious. Here, we estimated the effect of male killer infection on direct fitness (number of eggs laid, as a measure of fecundity, together with survival) and other life-history traits (development time and body size) in seven ladybird host/male killer combinations. Effects of male killers on fecundity ranged, as expected, from costly to neutral; however, we found evidence of reduced development time and increased survival and body size in infected strains. Greater body size in Spiroplasma-infected Harmonia axyridis corresponded to greater ovariole number and therefore higher potential fecundity. To our knowledge, this is the first report of direct benefits of male killer infection after explicitly controlling for indirect fitness effects. Neutral or deleterious fitness effects of male killer infection should not therefore be automatically assumed. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  4. Non-Covalent Interactions and Impact of Charge Penetration Effects in Linear Oligoacene Dimers and Single Crystals

    KAUST Repository

    Ryno, Sean

    2016-05-18

    Non-covalent interactions determine in large part the thermodynamic aspects of molecular packing in organic crystals. Using a combination of symmetry-adapted perturbation theory (SAPT) and classical multipole electrostatics, we describe the interaction potential energy surfaces for dimers of the oligoacene family, from benzene to hexacene. An analysis of these surfaces and a thorough assessment of dimers extracted from the reported crystal structures underline that high-order interactions (i.e., three-body non-additive interactions) must be considered in order to rationalize the details of the crystal structures. A comparison of the SAPT electrostatic energy with the multipole interaction energy demonstrates the importance of the contribution of charge penetration, which is shown to account for up to 50% of the total interaction energy in dimers extracted from the experimental single crystals; in the case of the most stable co-facial model dimers, this contribution is even larger than the total interaction energy. Our results highlight the importance of taking account of charge penetration in studies of the larger oligoacenes.

  5. Effects of pond salinization on survival rate of amphibian hosts infected with the chytrid fungus.

    Science.gov (United States)

    Stockwell, Michelle Pirrie; Storrie, Lachlan James; Pollard, Carla Jean; Clulow, John; Mahony, Michael Joseph

    2015-04-01

    The chytrid fungus Batrachochytrium dendrobatidis has been implicated in the decline and extinction of amphibian populations worldwide, but management options are limited. Recent studies show that sodium chloride (NaCl) has fungicidal properties that reduce the mortality rates of infected hosts in captivity. We investigated whether similar results can be obtained by adding salt to water bodies in the field. We increased the salinity of 8 water bodies to 2 or 4 ppt and left an additional 4 water bodies with close to 0 ppt and monitored salinity for 18 months. Captively bred tadpoles of green and golden bell frog (Litoria aurea) were released into each water body and their development, levels of B. dendrobatidis infection, and survival were monitored at 1, 4, and 12 months. The effect of salt on the abundance of nontarget organisms was also investigated in before and after style analyses. Salinities remained constant over time with little intervention. Hosts in water bodies with 4 ppt salt had a significantly lower prevalence of chytrid infection and higher survival, following metamorphosis, than hosts in 0 ppt salt. Tadpoles in the 4 ppt group were smaller in length after 1 month in the release site than those in the 0 and 2 ppt groups, but after metamorphosis body size in all water bodies was similar . In water bodies with 4 ppt salt, the abundance of dwarf tree frogs (Litoria fallax), dragonfly larvae, and damselfly larvae was lower than in water bodies with 0 and 2 ppt salt, which could have knock-on effects for community structure. Based on our results, salt may be an effective field-based B. dendrobatidis mitigation tool for lentic amphibians that could contribute to the conservation of numerous susceptible species. However, as in all conservation efforts, these benefits need to be weighed against negative effects on both target and nontarget organisms. © 2014 Society for Conservation Biology.

  6. Immunoregulatory Effects Triggered by Lactic Acid Bacteria Exopolysaccharides: New Insights into Molecular Interactions with Host Cells.

    Science.gov (United States)

    Laiño, Jonathan; Villena, Julio; Kanmani, Paulraj; Kitazawa, Haruki

    2016-08-15

    Researchers have demonstrated that lactic acid bacteria (LAB) with immunomodulatory capabilities (immunobiotics) exert their beneficial effects through several molecules, including cell wall, peptidoglycan, and exopolysaccharides (EPS), that are able to interact with specific host cell receptors. EPS from LAB show a wide heterogeneity in its composition, meaning that biological properties depend on the strain and. therefore, only a part of the mechanism of action has been elucidated for these molecules. In this review, we summarize the current knowledge of the health-promoting actions of EPS from LAB with special focus on their immunoregulatory actions. In addition, we describe our studies using porcine intestinal epithelial cells (PIE cells) as a model to evaluate the molecular interactions of EPS from two immunobiotic LAB strains and the host cells. Our studies showed that EPS from immunobiotic LAB have anti-inflammatory capacities in PIE cells since they are able to reduce the production of inflammatory cytokines in cells challenged with the Toll-like receptor (TLR)-4-agonist lipopolysaccharide. The effects of EPS were dependent on TLR2, TLR4, and negative regulators of TLR signaling. We also reported that the radioprotective 105 (RP105)/MD1 complex, a member of the TLR family, is partially involved in the immunoregulatory effects of the EPS from LAB. Our work described, for the first time, that LAB and their EPS reduce inflammation in intestinal epithelial cells in a RP105/MD1-dependent manner. A continuing challenge for the future is to reveal more effector-receptor relationships in immunobiotic-host interactions that contribute to the beneficial effects of these bacteria on mucosal immune homeostasis. A detailed molecular understanding should lead to a more rational use of immunobiotics in general, and their EPS in particular, as efficient prevention and therapies for specific immune-related disorders in humans and animals.

  7. Habitat amount modulates the effect of patch isolation on host-parasitoid interactions

    Directory of Open Access Journals (Sweden)

    Valérie eCoudrain

    2014-06-01

    Full Text Available 1.Habitat amount and patch isolation are important determinants of biodiversity and ecosystem functioning. We studied the separate and interactive effects of these two components of habitat fragmentation on host-parasitoid interactions in a replicated landscape-scale study. 2.We used trap-nesting solitary bees, wasps and their natural enemies as study system. We exposed trap nests in 30 tree patches in agricultural landscapes in northern Switzerland. Study sites were either (i adjacent to forest (adjacent, (ii distant from forest but connected through woody elements (connected or (iii distant from forest with no connecting woody elements (isolated. Independent of the three levels of isolation, the amount of woody habitat in the landscapes covered a gradient from 4 to 74%. 3.Host and parasitoid species richness increased with the amount of habitat in the landscape and was strongly reduced at isolated compared to adjacent and connected sites. Loss of host species richness was 21% at isolated compared to non-isolated sites, whereas parasitoid species richness decreased by 68%, indicating that the higher trophic level was more adversely affected by isolation. Most importantly, habitat amount and isolation had a pronounced interactive effect on parasitism: while isolation resulted in a strong decrease in parasitism in landscapes with low habitat amount, this effect was mitigated by high habitat amount. These interactive effects were consistent across the three years of the study. 4.The observed interplay between habitat amount and patch isolation may explain the often conflicting results in the habitat fragmentation literature and should be considered in future research on multitrophic communities and ecosystem functioning in fragmented landscapes.

  8. Immunoregulatory Effects Triggered by Lactic Acid Bacteria Exopolysaccharides: New Insights into Molecular Interactions with Host Cells

    Directory of Open Access Journals (Sweden)

    Jonathan Laiño

    2016-08-01

    Full Text Available Researchers have demonstrated that lactic acid bacteria (LAB with immunomodulatory capabilities (immunobiotics exert their beneficial effects through several molecules, including cell wall, peptidoglycan, and exopolysaccharides (EPS, that are able to interact with specific host cell receptors. EPS from LAB show a wide heterogeneity in its composition, meaning that biological properties depend on the strain and. therefore, only a part of the mechanism of action has been elucidated for these molecules. In this review, we summarize the current knowledge of the health-promoting actions of EPS from LAB with special focus on their immunoregulatory actions. In addition, we describe our studies using porcine intestinal epithelial cells (PIE cells as a model to evaluate the molecular interactions of EPS from two immunobiotic LAB strains and the host cells. Our studies showed that EPS from immunobiotic LAB have anti-inflammatory capacities in PIE cells since they are able to reduce the production of inflammatory cytokines in cells challenged with the Toll-like receptor (TLR-4-agonist lipopolysaccharide. The effects of EPS were dependent on TLR2, TLR4, and negative regulators of TLR signaling. We also reported that the radioprotective 105 (RP105/MD1 complex, a member of the TLR family, is partially involved in the immunoregulatory effects of the EPS from LAB. Our work described, for the first time, that LAB and their EPS reduce inflammation in intestinal epithelial cells in a RP105/MD1-dependent manner. A continuing challenge for the future is to reveal more effector-receptor relationships in immunobiotic-host interactions that contribute to the beneficial effects of these bacteria on mucosal immune homeostasis. A detailed molecular understanding should lead to a more rational use of immunobiotics in general, and their EPS in particular, as efficient prevention and therapies for specific immune-related disorders in humans and animals.

  9. Host size influences the effects of four isolates of an amphibian chytrid fungus.

    Science.gov (United States)

    Burrow, Angela K; Rumschlag, Samantha L; Boone, Michelle D

    2017-11-01

    Understanding factors that influence host-pathogen interactions is key to predicting outbreaks in natural systems experiencing environmental change. Many amphibian population declines have been attributed to an amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd). While this fungus is widespread, not all Bd-positive populations have been associated with declines, which could be attributed to differences in pathogen virulence or host susceptibility. In a laboratory experiment, we examined the effects of Bd isolate origin, two from areas with Bd-associated amphibian population declines (El Copé, Panama, and California, USA) and two from areas without Bd-related population declines (Ohio and Maine, USA), on the terrestrial growth and survival of American toad (Anaxyrus americanus) metamorphs reared in larval environments with low or high intraspecific density. We predicted that (1) Bd isolates from areas experiencing declines would have greater negative effects than Bd isolates from areas without declines, and (2) across all isolates, growth and survival of smaller toads from high-density larval conditions would be reduced by Bd exposure compared to larger toads from low-density larval conditions. Our results showed that terrestrial survival was reduced for smaller toads exposed to Bd with variation in the response to different isolates, suggesting that smaller size increased susceptibility to Bd. Toads exposed to Bd gained less mass, which varied by isolate. Bd isolates from areas with population declines, however, did not have more negative effects than isolates from areas without recorded declines. Most strikingly, our study supports that host condition, measured by size, can be indicative of the negative effects of Bd exposure. Further, Bd isolates' impact may vary in ways not predictable from place of origin or occurrence of disease-related population declines. This research suggests that amphibian populations outside of areas experiencing Bd

  10. Expected Effect of Deleterious Mutations on Within-Host Adaptation of Pathogens

    Science.gov (United States)

    2015-01-01

    ABSTRACT Adaptation is a common theme in both pathogen emergence, for example, in zoonotic cross-species transmission, and pathogen control, where adaptation might limit the effect of the immune response and antiviral treatment. When such evolution requires deleterious intermediate mutations, fitness ridges and valleys arise in the pathogen's fitness landscape. The effect of deleterious intermediate mutations on within-host pathogen adaptation is examined with deterministic calculations, appropriate for pathogens replicating in large populations with high error rates. The effect of deleterious intermediate mutations on pathogen adaptation is smaller than their name might suggest: when two mutations are required and each individual single mutation is fully deleterious, the pathogen can jump across the fitness valley by obtaining two mutations at once, leading to a proportion of adapted mutants that is 20-fold lower than that in the situation where the fitness of all mutants is neutral. The negative effects of deleterious intermediates are typically substantially smaller and outweighed by the fitness advantages of the adapted mutant. Moreover, requiring a specific mutation order has a substantially smaller effect on pathogen adaptation than the effect of all intermediates being deleterious. These results can be rationalized when the number of routes of mutation available to the pathogen is calculated, providing a simple approach to estimate the effect of deleterious mutations. The calculations discussed here are applicable when the effect of deleterious mutations on the within-host adaptation of pathogens is assessed, for example, in the context of zoonotic emergence, antigenic escape, and drug resistance. IMPORTANCE Adaptation is critical for pathogens after zoonotic transmission into a new host species or to achieve antigenic immune escape and drug resistance. Using a deterministic approach, the effects of deleterious intermediate mutations on pathogen adaptation

  11. Developing an Efficient and Cost Effective Ground-Penetrating Radar Field Methodology for Subsurface Exploration and Mapping of Cultural Resources on Public Lands

    National Research Council Canada - National Science Library

    Conyers, Lawrence B

    2006-01-01

    .... A new, emerging technology is the use of ground penetrating radar (GPR). However, in using this device due to the number of variables that can impact energy penetration and resolution, researchers are often not guaranteed a successful survey...

  12. Effects of immunosuppression on avian coccidiosis: cyclosporin A but not hormonal bursectomy abrogates host protective immunity.

    Science.gov (United States)

    Lillehoj, H S

    1987-01-01

    The effects of cyclosporin A (CsA) treatment and hormonal bursectomy on Eimeria tenella infection of chickens were investigated to evaluate the role of humoral antibody and cell-mediated immunity (CMI) in the host protective immunity to an intestinal protozoan disease, coccidiosis. Hormonal bursectomy had no significant effect on the host response to E. tenella. CsA treatment had a differential effect on the course of disease depending on how CsA was given relative to infection. Daily administration of CsA for 7 days beginning 1 day before primary infection with E. tenella enhanced disease resistance, whereas a single dose of CsA given before primary infection enhanced disease susceptibility compared with that of untreated controls. Chickens treated with CsA during the primary infection were resistant to reinfection at 5 weeks post-primary infection. Treatment of chickens immune to E. tenella with CsA at the time of secondary infection abrogated their resistance to reinfection despite the presence of high levels of coccidia-specific secretory immunoglobulin A and serum immunoglobulin G. Splenic lymphocytes obtained after CsA treatment demonstrated a substantially depressed concanavalin A response, but not a depressed lipopolysaccharide response. Because CsA was not directly toxic to parasites in vivo when administered during the secondary infection, these results suggest that CsA interacts with the immune system to allow priming during the primary infection, while interfering with the effector function of CMI during the secondary infection. Taken together, present findings indicate that CMI plays a major role in host protective immunity to E. tenella. PMID:3496277

  13. Effect of lactoferrin protein on red blood cells and macrophages: mechanism of parasite–host interaction

    Directory of Open Access Journals (Sweden)

    An

    2015-07-01

    Full Text Available Namrata Anand,1 Rupinder K Kanwar,2 Mohan Lal Dubey,1 R K Vahishta,3 Rakesh Sehgal,1,* Anita K Verma,4 Jagat R Kanwar2,*1Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; 2Nanomedicine Laboratory of Immunology and Molecular Biomedical Research, School of Medicine, Molecular and Medical Research Strategic Research Centre, Faculty of Health, Deakin University, Geelong, VIC, Australia; 3Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, 4Nanobiotech Laboratory, Department of Zoology, Kirorimal College, University of Delhi, Delhi, India*These authors contributed equally to this workBackground: Lactoferrin is a natural multifunctional protein known to have antitumor, antimicrobial, and anti-inflammatory activity. Apart from its antimicrobial effects, lactoferrin is known to boost the immune response by enhancing antioxidants. Lactoferrin exists in various forms depending on its iron saturation. The present study was done to observe the effect of lactoferrin, isolated from bovine and buffalo colostrum, on red blood cells (RBCs and macrophages (human monocytic cell line-derived macrophages THP1 cells.Methods: Lactoferrin obtained from both species and in different iron saturation forms were used in the present study, and treatment of host cells were given with different forms of lactoferrin at different concentrations. These treated host cells were used for various studies, including morphometric analysis, viability by MTT assay, survivin gene expression, production of reactive oxygen species, phagocytic properties, invasion assay, and Toll-like receptor-4, Toll-like receptor-9, and MDR1 expression, to investigate the interaction between lactoferrin and host cells and the possible mechanism of action with regard to parasitic infections.Results: The mechanism of interaction between host cells and lactoferrin have shown various aspects of gene

  14. City Branding : The effects of hosting sporting events: An empirical study of Singapore

    OpenAIRE

    Hansen, Matthew; Lee, Yen Wiee

    2010-01-01

    There is a growing amount of literature that investigates the various strategies and effects of city branding, but only a limited amount of research has been carried out pertaining to how sporting events can be used as a tool for city branding in a real world setting. By conducting an empirical study of Singapore, this study aims to contribute to the ongoing discussion on city branding by identifying how evaluations of a city differ for certain dimensions of its overall brand when it hosts di...

  15. Effect of Maruca vitrata (Lepidoptera: Crambidae) host plants on life-history parameters of the parasitoid Apanteles taragamae (Hymenoptera: Braconidae)

    NARCIS (Netherlands)

    Dannon, A.E.; Tamo, M.; Agboton, C.; Huis, van A.; Dicke, M.

    2012-01-01

    The effect of four host plant species of the herbivore Maruca vitrata Fabricius (Lepidoptera: Crambidae) on development time, longevity, fecundity and sex ratio of the parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) was investigated under laboratory conditions. The larvae were

  16. Penetrating keratoplasty in the cat. A clinically applicable model.

    Science.gov (United States)

    Bahn, C F; Meyer, R F; MacCallum, D K; Lillie, J H; Lovett, E J; Sugar, A; Martonyi, C L

    1982-06-01

    A series of 28 consecutive penetrating keratoplasties were performed on adult cats. Donor corneas (n = 14) were maintained in culture medium for 14--24 hours prior to transplantation. Rotational autografts (n = 7) were used to control for cell loss caused by culture maintenance as well as for the effects of surgery. Additional homografts (n = 7) were transplanted following removal of the corneal endothelium to study the extent of host corneal endothelial cell regeneration. Pre- and post-operative endothelial cell counts of the homografts made from specular micrographs demonstrated an average cell loss of 30% one month following surgery. A similar 30% average cell loss was present in the rotational autografts. Clinically, both homografts and autografts remained clear and were near normal in thickness. Homografts lacking endothelium exhibited persistent, severe edema that correlated with the inability of the host corneal endothelium to resurface the graft. Clinical and morphologic evidence of mild homograft rejection as observed in 15% of the animals that received normal homografts. Corneal endothelial cell loss following penetrating keratoplasty in the cat approximates that observed following the same procedure in the human. Additionally, regenerative capacity of the corneal endothelium in the cat, like that of the human, is limited. These features suggest that this cooperative, hardy animal is an excellent model in which to study many aspects of corneal transplantation that have direct application to the treatment of human corneal disease.

  17. Indirect effects of parasitism: costs of infection to other individuals can be greater than direct costs borne by the host.

    Science.gov (United States)

    Granroth-Wilding, Hanna M V; Burthe, Sarah J; Lewis, Sue; Herborn, Katherine A; Takahashi, Emi A; Daunt, Francis; Cunningham, Emma J A

    2015-07-22

    Parasitic infection has a direct physiological cost to hosts but may also alter how hosts interact with other individuals in their environment. Such indirect effects may alter both host fitness and the fitness of other individuals in the host's social network, yet the relative impact of direct and indirect effects of infection are rarely quantified. During reproduction, a host's social environment includes family members who may be in conflict over resource allocation. In such situations, infection may alter how resources are allocated, thereby redistributing the costs of parasitism between individuals. Here, we experimentally reduce parasite burdens of parent and/or nestling European shags (Phalacrocorax aristotelis) infected with Contracaecum nematodes in a factorial design, then simultaneously measure the impact of an individual's infection on all family members. We found no direct effect of infection on parent or offspring traits but indirect effects were detected in all group members, with both immediate effects (mass change and survival) and longer-term effects (timing of parents' subsequent breeding). Our results show that parasite infection can have a major impact on individuals other than the host, suggesting that the effect of parasites on population processes may be greater than previously thought. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  18. A Model of Post-Traumatic Epilepsy After Penetrating Brain Injuries: Effect of Lesion Size and Metal Fragments

    Science.gov (United States)

    Kendirli, M. Tansel; Rose, Dominique T.; Bertram, Edward H.

    2014-01-01

    Objective Penetrating brain injury (PBI) has the highest risk for inducing post-traumatic epilepsy and retained foreign materials such as bullet fragments carry the greatest risk. This study examines the potential contribution of copper, a major component of bullets, to the development of epilepsy following PBI. Methods Anesthetized adult male rats received a penetrating injury from the dorsal cortex to the ventral hippocampus from a high speed small bit drill. In one group of animals, copper wire was inserted into the lesion. Control animals had only the lesion or the lesion plus stainless steel wire (biologically inert foreign body). From 6 to up to 11 months following the injury the rats were monitored intermittently for the development of epilepsy with video-EEG. A separate set of animals was examined for possible acute seizures in the week following the injury. Results 22 of the 23 animals with copper wire developed chronic epilepsy compared to 3 of the 20 control rats (lesion and lesion with stainless steel). Copper was associated with more extensive injury. The control rats with epilepsy had larger lesions. In the acute injury group, there was no difference in the incidence of seizures (83% lesion plus stainless steel, 70% lesion plus copper). Conclusions Copper increases the risk for epilepsy and may increase damage over time, but there were no differences between the groups in the incidence of acute post-injury seizures. Lesion size may contribute to epilepsy development in lesion only animals. Copper maybe an independent risk factor for the development of epilepsy and possible secondary injury, but lesion size also contributes to the development of epilepsy. The consequences of prolonged exposure of the brain to copper observed in these animals may have clinical implications that require further evaluation. PMID:25470332

  19. Mobile termination and mobile penetration

    OpenAIRE

    Hurkens, Sjaak; Jeon, Doh-Shin

    2009-01-01

    In this paper, we study how access pricing affects network competition when subscription demand is elastic and each network uses non-linear prices and can apply termination-based price discrimination. In the case of a fixed per minute termination charge, we find that a reduction of the termination charge below cost has two oppos- ing effects: it softens competition but helps to internalize network externalities. The former reduces mobile penetration while the latter boosts it. We find that fi...

  20. Dynamic Response of Graphitic Flakes in Nematic Liquid Crystals: Confinement and Host Effect

    Directory of Open Access Journals (Sweden)

    Weiwei Tie

    2017-09-01

    Full Text Available Electric field-induced reorientation of suspended graphitic (GP flakes and its relaxation back to the original state in a nematic liquid crystal (NLC host are of interest not only in academia, but also in industrial applications, such as polarizer-free and optical film-free displays, and electro-optic light modulators. As the phenomenon has been demonstrated by thorough observation, the detailed study of the physical properties of the host NLC (the magnitude of dielectric anisotropy, elastic constants, and rotational viscosity, the size of the GP flakes, and cell thickness, are urgently required to be explored and investigated. Here, we demonstrate that the response time of GP flakes reorientation associated with an NLC host can be effectively enhanced by controlling the physical properties. In a vertical field-on state, higher dielectric anisotropy and higher elasticity of NLC give rise to quicker reorientation of the GP flakes (switching from planar to vertical alignment due to the field-induced coupling effect of interfacial Maxwell-Wagner polarization and NLC reorientation. In a field off-state, lower rotational viscosity of NLC and lower cell thickness can help to reduce the decay time of GP flakes reoriented from vertical to planar alignment. This is mainly attributed to strong coupling between GP flakes and NLC originating from the strong π-π interaction between benzene rings in the honeycomb-like graphene structure and in NLC molecules. The high-uniformity of reoriented GP flakes exhibits a possibility of new light modulation with a relatively faster response time in the switching process and, thus, it can show potential application in field-induced memory and modulation devices.

  1. Airborne ground penetrating radar: practical field experiments

    CSIR Research Space (South Africa)

    Van Schoor, Michael

    2013-10-01

    Full Text Available The performance of ground penetrating radar (GPR) under conditions where the ground coupling of the antenna is potentially compromised is investigated. Of particular interest is the effect of increasing the distance between the antennae...

  2. Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize

    OpenAIRE

    Jordaan, Elizabeth M.; De Waele, D.

    1988-01-01

    The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae inf...

  3. Efectos de tratamientos de labranza sobre la resistencia a la penetración de un Andisol Effects of tillage treatments on penetration resistance on an andisol

    Directory of Open Access Journals (Sweden)

    Jiménez Javier

    1992-06-01

    Full Text Available Se evaluó el efecto sobre la resistencia a la penetración de cuatro implementos de labranza (arado de cinceles, arado de discos, rastrillo californiano y arado rotatorio en un Andisol (Andic-Eutropept serie Tibaitatá. Para las medidas, se utilizó un penetrómetro registrador digital. Los resultados mostraron que los tratamientos que involucraron arado rotatorio y arado de discos y rastrillo fueron los que causaron el mayor grado de aflojamiento del suelo. Sin embargo, dichos tratamientos fueron los más susceptibles a la compactación por pase de llantas. No se pudo concluir lo planteado por la literatura de que el fondo de surco de arado es una zona de alto
    riesgo de compactación del subsuelo. La resistencia a la penetración resultó un buen indicador para evaluar efectos físicos sobre el suelo causarlos por implementos de labranza y él tránsito de maquinaria.The effects on Cone Penetration Resistance caused by four tillage implements (chisel plow, disk plough, disk harrow and rotatiller were assesed on an Andisol, using a digital penetrometer. The results showed the treatments using rota-tiller and those using disk plough and disk harrow caused
    the maximun soilloosening. However those treatments were the most sensitive to compaction due to the traffic of tractor
    wheels. This work did not present conclusive evidence that bottom of furrow made by disk plough is a place of high risk for subsoil cornpactlon. Cone penetration resistance looks like a good index to assess changes in physical properties of the soil caused by tillage operations and machinery traffic.

  4. Taser penetrating ocular injury.

    Science.gov (United States)

    Ng, Weng; Chehade, Mark

    2005-04-01

    To describe the presentation and treatment of a Taser penetrating ocular injury. Case report. A 50-year-old man with a Taser injury 1.5 cm below the right lower eyelid margin was admitted to the emergency department of a tertiary hospital. The case report describes the ophthalmic assessment, investigation, treatment, and outcome of the Taser barb penetrating ocular injury. The Taser has a fish hook barb that caused a full-thickness wound adequately large for vitreous to escape when the Taser was removed. Consequently, the scleral wound was repaired and cryopexy was performed. The affected eye made a satisfactory recovery, and the visual acuity was 6/9 with a pinhole 1 week after operation. Any Taser injury around the orbits should raise the suspicion of a penetrating ocular injury. In likely cases, removal of the Taser should be performed in an operating theater under general anesthesia.

  5. Application of 2D electrical resistivity imaging and cone penetration test (CPT) to assess the harzadous effect of near surface water on foundations in Lagos Nigeria

    Science.gov (United States)

    Adewoyin, O. O.; Joshua, E. O.; Akinyemi, M. L.; Omeje, M.; Joel, E. S.

    2017-05-01

    Adequate information on the condition of the subsurface is very important for site evaluation for engineering purposes. In this study two dimensional (2D) geoelectrical resistivity survey and cone penetration tests were conducted to study the hazardous effect of excess near surface water on the foundation of building in a reclaimed land located at Victoria Island area of Lagos State. The results of the inverted 2D geoelectrical resistivity data revealed three distinct geoelectrical layers characterized by low to moderate electrical resistivity of 2.23 and 129Ωm and 9.46 to 636Ωm respectively. The topsoil is characterized by wet sandy soil, which is underlain by sandy clay and banded at the below by a geologic formation of low resistivity which is suspected to be clay. The clay material may be responsible for the excess water retention observed in the area. The CPT method on the other hand revealed a geological formation of low resistance to penetration between 2-3 kg/cm2 from the topsoil to a depth of 7 m, which may be the effect of excess water in the near surface. This study revealed that the foundation of building may not be founded directly on the soil in any reclaimed land as this may result in collapse as a result of upward migration of water to the near surface.

  6. Small alteration - big impacts: effects of small-scale riparian forest management on host-parasite dynamics in streams.

    Science.gov (United States)

    Lagrue, C; Besson, A A; Lecerf, A

    2018-01-01

    Environmental changes and ecological disturbances can have large and unpredictable effects on parasite dynamics. Increasing human impacts on freshwater ecosystems through land use may thus modify the distribution and abundance of parasites and have cascading effects on host populations. Here we tested the effects of small-scale riparian forest management on the nematode Cystidicoloides ephemeridarum and its insect intermediate host Ephemera danica in forested streams. We assessed the impacts of harvesting riparian trees on parasite prevalence and abundance concomitantly with host densities. We also looked at upstream and downstream reaches to document potential cascading effects on unaltered stream sections mediated by aerial dispersal of adult mayfly or downstream drift of E. danica larvae. We show that host densities and parasite levels (prevalence and abundance) increased significantly following riparian tree removal. Overall, parasite densities showed a 6- to 66-fold increase in harvested reaches compared to upstream, pristine reaches. Similar effects were also clear downstream of the disturbance. Thus, despite the small extent of riparian forest alteration along the study streams, both parasite and intermediate host were strongly affected. Small-scale riparian forest management may thus have large, unforeseen impacts on some aspects of freshwater ecosystem structure and functioning that are often ignored. Generally, understanding how human perturbations influence parasites is vital when trying to predict overall impacts on ecosystem structure and functioning, and how changes in infection dynamics may further affect host species.

  7. Penetration Testing In System Administration

    Directory of Open Access Journals (Sweden)

    Muhammad Zunnurain Hussain

    2017-06-01

    Full Text Available In this paper Authors will be discussing the penetration testing in system administration and challenges faced by the industry in securing the data and information using different techniques. Penetration Testing is modern technique of assessing the vulnerabilities in the system. It has been performed to explore all the loop holes in the system and the tester behave like an attacker. All the potential weaknesses access to data manually or automatically being checked and verifies by the tester. The purpose of this activity is to gather all the required information to secure the data before real attack effects the system during the process port scanning and other activities were performed and finally as report will be made to suggest improvement in the system to secure it. It is very challenging these days to secure the communication between two users although people use different encryption techniques 1.

  8. Partial blood meal, carbohydrate availability, and bloodfeeding-postponement effects on human host avidity and deet repellency in Aedes albopictus.

    Science.gov (United States)

    Xue, Rui-De; Barnard, Donald R

    2009-12-01

    Host avidity and deet repellency were measured in partially bloodfed Aedes albopictus provided 10% sucrose, water, or nothing when access to a human host was postponed for 1 to 72 h after a partial blood meal. Carbohydrate availability and postfeeding time influenced host avidity, but partial blood meal effects were not significant. Mean host avidity declined significantly between hours 1 and 6 (range 50-18%) but increased significantly between hours 24 (54%) and 72 (68%) after a partial blood meal. Females provided sucrose solution and females denied sucrose or water showed the least (29%) and most (39%) host avidity, regardless of other treatment effects. The longest and shortest deet protection times were 8.5 h against females provided sucrose and 7.3 h against females denied sucrose or water, respectively. Denial of carbohydrate sustenance significantly increased host avidity and deet repellency in partially bloodfed female Ae. albopictus, whereas sucrose availability led to reduced host responding activity and decreased repellency of deet.

  9. High-velocity penetrators

    Science.gov (United States)

    Lundgren, Ronald G.

    This paper summarizes the results of studies, coupled with a series of tests, that investigated rigid-body projectiles (penetrators) at high (up to 5500 ft/sec) velocities. Before these studies, it had been hypothesized that a velocity limit would be reached at which increasing the velocity would not commensurately increase depth of penetration into a target. It was further inferred that a given velocity/ penetration depth curve would avalanche into the hydrodynamic regime; that is, increasing the velocity past a certain point would decrease penetration performance. The test series utilized 1/2-in., 3-in., and 5 1/2-in. diameter, ogive-nose steel projectiles and grout and concrete targets. The tests confirmed that penetration depth increased as striking velocity increased to 4000 ft/sec. However, beyond striking velocities of 4000 ft/sec, asymmetric erosion and indentation of the projectile nose from the aggregate caused the projectile trajectories to deviate severely from the target centerline. These trajectory deviations caused the projectile to exit the side of the target, severely bend, break, or exhibit decreased penetration performance, confirming the hypothesis. Clearly, these results were dependent on the specific material and geometric parameters. The projectiles had 3.0 and 4.25 CRH (Caliber-Radius-Head) nose shapes and were heat-treated to R(sub c) 38-40. The grout targets had a maximum aggregate diameter of 3/16 in. and a nominal unconfined compressive strength of 2.5 ksi. The concrete targets had a maximum aggregate diameter of 3/4 in. and unconfined compressive strength of 5.5 ksi.

  10. Does ligand-receptor mediated competitive effect or penetrating effect of iRGD peptide when co-administration with iRGD-modified SSL?

    Science.gov (United States)

    Zhang, Wei-Qiang; Yu, Ke-Fu; Zhong, Ting; Luo, Li-Min; Du, Ruo; Ren, Wei; Huang, Dan; Song, Ping; Li, Dan; Zhao, Yang; Wang, Chao; Zhang, Xuan

    2015-12-01

    Ligand-mediated targeting of anticancer therapeutic agents is a useful strategy for improving anti-tumor efficacy. It has been reported that co-administration of a tumor-penetrating peptide iRGD (CRGDK/RGPD/EC) enhances the efficacy of anticancer drugs. Here, we designed an experiment involving co-administration of iRGD-SSL-DOX with free iRGD to B16-F10 tumor bearing mice to examine the action of free iRGD. We also designed an experiment to investigate the location of iRGD-modified SSL when co-administered with free iRGD or free RGD to B16-F10 tumor bearing nude mice. Considering the sequence of iRGD, we selected the GPDC, RGD and CRGDK as targeting ligands to investigate the targeting effect of these peptides compared with iRGD on B16-F10 and MCF-7 cells, with or without enzymatic degradation. Finally, we selected free RGD, free CRGDK and free iRGD as ligand to investigate the inhibitory effect on RGD-, CRGDK- or iRGD-modified SSL on B16-F10 or MCF-7 cells. Our results indicated that iRGD targeting to tumor cells was ligand-receptor mediated involving RGD to αv-integrin receptor and CRGDK to NRP-1 receptor. Being competitive effect, the administration of free iRGD would not be able to further enhance the anti-tumor activity of iRGD-modified SSL. There is no need to co-administrate of free iRGD with the iRGD-modified nanoparticles for further therapeutic benefit.

  11. Effect of landscape features on the relationship between Ixodes ricinus ticks and their small mammal hosts.

    Science.gov (United States)

    Perez, Grégoire; Bastian, Suzanne; Agoulon, Albert; Bouju, Agnès; Durand, Axelle; Faille, Frédéric; Lebert, Isabelle; Rantier, Yann; Plantard, Olivier; Butet, Alain

    2016-01-15

    The consequences of land use changes are among the most cited causes of emerging infectious diseases because they can modify the ecology and transmission of pathogens. This is particularly true for vector-borne diseases which depend on abiotic (e.g. climate) and biotic conditions (i.e. hosts and vectors). In this study, we investigated how landscape features affect the abundances of small mammals and Ixodes ricinus ticks, and how they influence their relationship. From 2012 to 2014, small mammals and questing I. ricinus ticks were sampled in spring and autumn in 24 sites located in agricultural and forest landscapes in Brittany, France. We tested the effects of landscape features (composition and configuration) on the abundances of small mammal species and immature ticks and their relationship. Additionally, we quantified the larval tick burden of small mammals in 2012 to better describe this relationship. The nymph abundance was positively influenced by the larval occurrence and the wood mouse Apodemus sylvaticus abundance the previous spring because they hosted tenfold more larvae than the bank vole Myodes glareolus. The bank vole abundance in spring and autumn had a negative and positive effect, respectively, on the nymph abundance. In agricultural landscapes, wood mice were positively influenced by woodland cover and woodland/hedgerow-grassland ecotone, whereas bank voles showed the opposite or non-significant responses to these landscape variables. The woodland cover had a positive effect on immature ticks. The landscape configuration, likely by affecting the landscape connectivity, influences the small mammal communities in permanent habitats. Our study showed that the wood mouse, due to its dominance and to its tolerance to ticks, feeds a substantial proportion of larvae. The acquired resistance to ticks in the bank vole can reduce its role as a trophic resource over time. The nymph abundance seems indirectly influenced by landscape features via their

  12. Session: Hard Rock Penetration

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Ground penetrating radar

    CERN Document Server

    Daniels, David J

    2004-01-01

    Ground-penetrating radar has come to public attention in recent criminal investigations, but has actually been a developing and maturing remote sensing field for some time. In the light of recent expansion of the technique to a wide range of applications, the need for an up-to-date reference has become pressing. This fully revised and expanded edition of the best-selling Surface-Penetrating Radar (IEE, 1996) presents, for the non-specialist user or engineer, all the key elements of this technique, which span several disciplines including electromagnetics, geophysics and signal processing. The

  14. Sphere impact and penetration into wet sand

    KAUST Repository

    Marston, J. O.

    2012-08-07

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  15. A multicomponent microemulsion using rational combination strategy improves lung cancer treatment through synergistic effects and deep tumor penetration.

    Science.gov (United States)

    Qu, Ding; Guo, Mengfei; Qin, Yue; Wang, Lixiang; Zong, Bing; Chen, Yunyan; Chen, Yan

    2017-11-01

    Previously, we have developed a multicomponent-based microemulsion composed of etoposide, coix seed oil, and ginsenoside Rh2 (ECG-MEs). In this study, our goal was to validate the feasibility of ECG-MEs in lung cancer treatment and explore the mechanism underling the enhanced antitumor efficacy. The optimal weight ratio of ginsenoside Rh2 (G-Rh2) in ECG-MEs was determined as 3% (wt%), that was capable of forming the microemulsion readily with small particle size and high drug encapsulation efficiency. In cellular studies, the intracellular fluorescence of human non-small cell lung cancer (A549) cells treated with fluorescein isothiocyanate-labeled ECG-MEs (FITC/ECG-MEs) was significantly higher than that of various controls, leading to the obviously synergistic anticancer activities in cytotoxicity and in vitro cell apoptosis induction. The anticancer efficacy in vivo results showed that ECG-MEs markedly inhibited the growth of A549 tumor xenografts, potently induced tumor cells apoptosis, and obviously prolonged the survival time of mice. Of note, the mechanisms of enhanced anticancer efficiency were connected with the small size-mediated deep tumor penetration and increase in serum concentration of T helper 1 (Th1) cytokines. In summary, ECG-MEs exerting the rational drug combination strategy offers a solid evidence for lung cancer treatment, and has a promising potential for clinical application.

  16. Effects of Host-rock Fracturing on Elastic-deformation Source Models of Volcano Deflation.

    Science.gov (United States)

    Holohan, Eoghan P; Sudhaus, Henriette; Walter, Thomas R; Schöpfer, Martin P J; Walsh, John J

    2017-09-08

    Volcanoes commonly inflate or deflate during episodes of unrest or eruption. Continuum mechanics models that assume linear elastic deformation of the Earth's crust are routinely used to invert the observed ground motions. The source(s) of deformation in such models are generally interpreted in terms of magma bodies or pathways, and thus form a basis for hazard assessment and mitigation. Using discontinuum mechanics models, we show how host-rock fracturing (i.e. non-elastic deformation) during drainage of a magma body can progressively change the shape and depth of an elastic-deformation source. We argue that this effect explains the marked spatio-temporal changes in source model attributes inferred for the March-April 2007 eruption of Piton de la Fournaise volcano, La Reunion. We find that pronounced deflation-related host-rock fracturing can: (1) yield inclined source model geometries for a horizontal magma body; (2) cause significant upward migration of an elastic-deformation source, leading to underestimation of the true magma body depth and potentially to a misinterpretation of ascending magma; and (3) at least partly explain underestimation by elastic-deformation sources of changes in sub-surface magma volume.

  17. Effects of Host Diet on Romanomermis culicivorax, a Mermithid Parasite of Mosquitoes.

    Science.gov (United States)

    Gordon, R; Squires, J M; Babie, S J; Burford, I R

    1981-07-01

    When larval mosquitoes (Aedes aegypti) infected with the mermithid nematode Romanomermis culicivorax were fed on a diet low in quantity or protein content or both, the number of postparasites which emerged from the hosts decreased and host mortality increased marginally. Parasitic development was prolonged and became asynchronous in nutritionally deprived hosts. Nematodes emerged from insects infected by more than one nematode before the remaining juveniles comprising such infections had completed parasitic development; this resulted in substantial reductions in postparasite nttmbers. Host development was retarded by low protein and/or reduced diets. Postparasites emerging from second and third instars were reduced in size and in the amount of stored nutriment compared to those recovered from hosts fed on a high protein diet ad libitum. A greater proportion of the rnermithids developed into males in hosts fed on reduced diets but not in hosts fed on low protein diets.

  18. Correction of astigmatism after penetrating keratoplasty by relaxing incision with compression suture: a comparison between the guiding effect of photokeratoscope and of computer-assisted videokeratography.

    Science.gov (United States)

    Chang, Sheng-Ming; Su, Chuan-Yi; Lin, Chang-Ping

    2003-07-01

    To report the results of astigmatism correction after penetrating keratoplasty by relaxing incision with compression suture and to compare the guiding ability of a photokeratoscope with that of computer-assisted videokeratography. In the two independent retrospective series, 11 eyes received a relaxing incision with compression suture guided by photokeratoscope or computer-assisted videokeratography. In 22 eyes, the relaxing incision with compression suture showed a mean 56% reduction in astigmatism and 78% reduction in vector-calculated astigmatism. The mean postoperative visual acuity was improved 2.92 Landolt lines. The 11 eyes in which treatment was guided by photokeratoscope demonstrated a mean reduction of 50% and 71% in astigmatism and vector-calculated astigmatism, respectively, and visual acuity increased 2.44 Landolt lines. Another 11 eyes in which treatment was guided by computer-assisted videokeratography achieved a mean reduction of 67% and 90% in astigmatism and vector-calculated astigmatism, respectively, together with 3.41 Landolt lines improvement in visual acuity. There were no significant differences in astigmatism correction and visual acuity improvement between the two groups. The results demonstrate that the relaxing incision with compression suture is an effective and safe procedure for correcting high astigmatism after penetrating keratoplasty. The two instruments have no significant difference in their guiding capacities for this procedure.

  19. Assessment of penetrant and vehicle mixture properties on transdermal permeability using a mixed effect pharmacokinetic model of ex vivo porcine skin.

    Science.gov (United States)

    Chittenden, Jason T; Riviere, Jim E

    2016-10-01

    The accurate prediction of the rate and extent of transdermal absorption from topical exposure to chemical mixtures would be beneficial in risk assessment and drug delivery applications. The isolated perfused porcine skin flap (IPPSF) has been used as an ex vivo model for assessing transdermal absorption from topical exposures. A mixed effect, pharmacokinetic tissue model was used to model finite dose, transdermal, absorption data from IPPSF experiments for 12 penetrants dosed in up to 10 different vehicles. The model was able to identify permeability constant, while accounting for between and within unit variability, across the entire data set. This approach provides a platform for exploring the relationship between covariates (chemical descriptors and functions thereof) and the model parameters. Successive models were employed that reduced the overall variability in the parameter estimate by modeling the parameters as functions of the covariates. Log kp was initially modeled as a function of LogP and MW of the pure penetrant (adjusted r2  = 0.48). The addition of mixture factors to account for the different dosing vehicles further improved the relationship: to r2  = 0.56 with Connolly molecular area (CMA) and r2  = 0.78 with the further addition of total polar surface area difference (TPSAd). The pharmacokinetic model and quantitative structure property relationship (QSPR) developed for the IPPSF may be relevant to clinical transdermal formulation development. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Effectiveness of ants as pollinators of Lobularia maritima: effects on main sequential fitness components of the host plant.

    Science.gov (United States)

    Gómez, J M

    2000-01-01

    The effectiveness of ants as pollinators of Lobularia maritima (Cruciferae) was experimentally analyzed by assessing (1) their quantitative importance at flowers; (2) their effect on host plant seed production; (3) their effect on the performance of host plant progeny, estimated as seed germination, seedling emergence, seedling survival to flowering, and (4) the overall effect of ants on a cumulative, more realistic measure of plant fitness related to the recruitment probability. Flowers of L. maritima were visited during the 2 years of study (1996 and 1997) by more than 50 pollinator species belonging to about 30 families of disparate taxonomic affiliation, notably ants and flies. There was significant seasonal variability in insect abundance and type. Ants, especially Camponotus micans (Formicidae), visited the flowers of L. maritima in summer, representing 81.2% of the visits during this season. This ant species acted as a pollinator of L. maritima, with flowers visited exclusively by ants producing significantly more seeds than flowers from which all pollinators were excluded, whereas flowers visited by only winged insects did not differ from self-pollination. Ant-pollinated flowers produced seeds with a germination rate comparable to the other treatments. Moreover, seedlings from these seeds emerged as fast, and survived at the same rate as controls. Consequently, both ants and winged insects had similar overall effects on host plant recruitment probability (0.6 and 0.7% of initial ovules produced flowering offspring, respectively), a result similar to that of open-pollinated flowers (1.0%). This study demonstrated that the overall effectiveness of the ant C. micans as a summer pollinator of L. maritima was as high as that of other winged insects, contributing not only to the seed production of this crucifer but also to the recruitment of new flowering offspring.

  1. in penetrating abdominal trauma

    African Journals Online (AJOL)

    particularly in trauma surgery. The benefits of ERAS/ERPs are well established. They have shown faster physiological patient recovery, and reduced length of hospital stay without. Enhanced recovery after surgery (ERAS) in penetrating abdominal trauma: A prospective single-center pilot study. TRAUMA. M R Moydien, R ...

  2. Penetration resistant barrier

    Science.gov (United States)

    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.

  3. Host finding by Uscana lariophaga (Hymenoptera: Trichogrammatidae) in stored cowpea : the effect of distance, time interval, host patch size and spatial orientation

    NARCIS (Netherlands)

    Stolk, C.; Ghimire, M.N.; Souquié, S.; Werf, van der W.; Huis, van A.

    2005-01-01

    Host finding and parasitization by Uscana lariophaga Steffan, a potential biocontrol agent of the storage pest Callosobruchus maculatus (Fabricius), were investigated in stored cowpea. Host finding was shown to be a function of distance, time, host patch size and the spatial position of U.

  4. Visual Rehabilitation After Penetrating Keratoplasty.

    Science.gov (United States)

    Asena, Leyla; Altınörs, Dilek D

    2016-11-01

    Here, our aim was to report our treatment strategies and their results performed for visual rehabilitation after penetrating keratoplasty. The medical records of 98 patients (54 male/44 female), with results from 104 eyes, who underwent penetrating keratoplasty between January 2013 and January 2015 at the Baskent University Faculty of Medicine, Department of Ophthalmology were reviewed. Patient age, indication for penetrating keratoplasty, interventions performed for visual rehabilitation, follow-up duration, topographic and refractive astigmatism at the end of follow-up, and final best corrected visual acuity results were recorded. Mean age of patients was 54 ± 23 years. Indications for penetrating keratoplasty included keratoconus, Fuchs endothelial dystrophy, pseudophakic bullous keratopathy, and corneal scarring. The mean duration of follow-up was 23 ± 11.5 months. Topography-guided suture adjustment and selective suture removal were performed 2 to 6 weeks and after 3 months in eyes with more than 3 diopters of corneal astigmatism in patients who had continuous and interrupted sutures. Spectacle correction was administered for 86 eyes (83%), and contact lenses including rigid gas-permeable and scleral lenses were fitted in 18 eyes (17%) in patients who were unsatisfied with spectacle correction. Relaxing corneal incisions were performed in 23 eyes (22%), and toric intraocular lens implantations were performed in 34 eyes (33%) with cataracts. The mean topographic and absolute refractive astigmatism at the end of follow-up was 3.4 ± 2.6 and 3.6 ± 1.9 diopters. Topography-guided suture adjustment and selective suture removal are effective for minimizing early postoperative astigmatism. If significant astigmatism remains after suture removal, which cannot be corrected by optical means, then further surgical procedures including relaxing incisions and toric intraocular lens implantation can be performed.

  5. Tumor penetrating peptides

    Directory of Open Access Journals (Sweden)

    Tambet eTeesalu

    2013-08-01

    Full Text Available 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

  6. [Effects of Frankincense and Myrrh essential oil on transdermal absorption in vitro of Chuanxiong and penetration mechanism of skin blood flow].

    Science.gov (United States)

    Zhu, Xiao-Fang; Luo, Jing; Guan, Yong-Mei; Yu, Ya-Ting; Jin, Chen; Zhu, Wei-Feng; Liu, Hong-Ning

    2017-02-01

    The aim of this paper was to explore the effects of Frankincense and Myrrh essential oil on transdermal absorption in vitro of Chuanxiong, and to investigate the possible penetration mechanism of their essential oil from the perspective of skin blood perfusion changes. Transdermal tests were performed in vitro with excised mice skin by improved Franz diffusion cells. The cumulative penetration amounts of ferulic acid in Chuanxiong were determined by HPLC to investigate the effects of Frankincense and Myrrh essential oil on transdermal permeation properties of Chuanxiong. Simultaneously, the skin blood flows were determined by laser flow doppler. The results showed that the cumulative penetration amount of ferulic acid in Chuanxiong was (8.13±0.76) μg•cm⁻² in 24 h, and was (48.91±4.87), (57.80±2.86), (63.34±4.56), (54.17±4.40), (62.52±7.79) μg•cm⁻² respectively in Azone group, Frankincense essential oil group, Myrrh essential oil, frankincense and myrrh singly extracted essential oil mixture group, and frankincense and myrrh mixed extraction essential oil group. The enhancement ratios of each essential oil groups were 7.68, 8.26, 7.26, 8.28, which were slightly greater than 6.55 in Azone group. In addition, as compared with the conditions before treatment, there were significant differences and obvious increasing trend in blood flow of rats in Frankincense essential oil group, Myrrh essential oil group, frankincense and myrrh singly extracted essential oil mixture group, and frankincense and myrrh mixed extraction essential oil group when were dosed at 10, 20, 30, 10 min respectively, indicating that the skin blood flows were increased under the effects of Frankincense and Myrrh essential oil to a certain extent. Thus, Frankincense and Myrrh essential oil had certain effect on promoting permeability of Chuanxiong both before and after drug combination, and may promote the elimination of drugs from epidermis to dermal capillaries through increase of

  7. The effect of high-pressure devitrification and densification on ballistic-penetration resistance of fused silica

    Science.gov (United States)

    Avuthu, Vasudeva Reddy

    perhaps alpha-quartz) within fused silica during ballistic impact. To rationalize the findings obtained, the all-atom molecular-level computational analysis is complemented by a series of quantum-mechanics density functional theory (DFT) computations. The latter computations enable determination of the relative potential energies of the fused silica, alpha-quartz and stishovite under ambient pressure (i.e. under their natural densities) as well as under imposed (as high as 50 GPa) pressures (i.e. under higher densities) and shear strains. In addition, the transition states associated with various fused-silica devitrification processes were identified. In the second part of the present work, the molecular-level computational results obtained in the first portion of the work are used to enrich a continuum-type constitutive model (that is, the so-called Johnson-Holmquist-2, JH2, model) for fused silica. Since the aforementioned devitrification and permanent-densification processes modify the response of fused silica to the pressure as well as to the deviatoric part of the stress, changes had to be made in both the JH2 equation of state and the strength model. To assess the potential improvements with respect to the ballistic-penetration resistance of this material brought about by the fused-silica devitrification and permanent-densification processes, a series of transient non-linear dynamics finite element analyses of the transverse impact of a fused-silica test plate with a solid right-circular cylindrical steel projectile was conducted. The results obtained revealed that, provided the projectile incident velocity and, hence, the attendant pressure, is sufficiently high, fused silica can undergo impact-induced energy-consuming devitrification, which improves its ballistic-penetration resistance.

  8. The effect of Bulgarian propolis against Trypanosoma cruzi and during its interaction with host cells

    Directory of Open Access Journals (Sweden)

    Andréia Pires Dantas

    2006-03-01

    Full Text Available Propolis has shown activity against pathogenic microorganisms that cause diseases in humans and animals. The ethanol (Et-Blg and acetone (Ket-Blg extracts from a Bulgarian propolis, with known chemical compositions, presented similar activity against tissue culture-derived amastigotes. The treatment of Trypanosoma cruzi-infected skeletal muscle cells with Et-Blg led to a decrease of infection and of the intracellular proliferation of amastigotes, while damage to the host cell was observed only at concentration 12.5 times higher than those affecting the parasite. Ultrastructural analysis of the effect of both extracts in epimastigotes revealed that the main targets were the mitochondrion and reservosomes. Et-Blg also affected the mitochondrion-kinetoplast complex in trypomastigotes, offering a potential target for chemotherapeutic agents.

  9. Anti-Leishmania activity of new ruthenium(II) complexes: Effect on parasite-host interaction.

    Science.gov (United States)

    Costa, Mônica S; Gonçalves, Yasmim G; Nunes, Débora C O; Napolitano, Danielle R; Maia, Pedro I S; Rodrigues, Renata S; Rodrigues, Veridiana M; Von Poelhsitz, Gustavo; Yoneyama, Kelly A G

    2017-10-01

    Leishmaniasis is a parasitic disease caused by protozoa of the genus Leishmania. The many complications presented by the current treatment - including high toxicity, high cost and parasite resistance - make the development of new therapeutic agents indispensable. The present study aims to evaluate the anti-Leishmania potential of new ruthenium(II) complexes, cis‑[RuII(η2-O2CR)(dppm)2]PF6, with dppm=bis(diphenylphosphino)methane and R=4-butylbenzoate (bbato) 1, 4-(methylthio)benzoate (mtbato) 2 and 3-hydroxy-4-methoxybenzoate (hmxbato) 3, in promastigote cytotoxicity and their effect on parasite-host interaction. The cytotoxicity of complexes was analyzed by MTT assay against Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis, Leishmania (Leishmania) infantum promastigotes and the murine macrophage (RAW 264.7). The effect of complexes on parasite-host interaction was evaluated by in vitro infectivity assay performed in the presence of two different concentrations of each complex: the promastigote IC50 value and the concentration nontoxic to 90% of RAW 264.7 macrophages. Complexes 1-3 exhibited potent cytotoxic activity against all Leishmania species assayed. The IC50 values ranged from 7.52-12.59μM (complex 1); 0.70-3.28μM (complex 2) and 0.52-1.75μM (complex 3). All complexes significantly inhibited the infectivity index at both tested concentrations. The infectivity inhibitions ranged from 37 to 85%. Interestingly, the infectivity inhibitions due to complex action did not differ significantly at either of the tested concentrations, except for the complex 1 against Leishmania (Leishmania) infantum. The infectivity inhibitions resulted from reductions in both percentage of infected macrophages and number of parasites per macrophage. Taken together the results suggest remarkable leishmanicidal activity in vitro by these new ruthenium(II) complexes. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Effects of copper nanoparticle exposure on host defense in a murine pulmonary infection model

    Directory of Open Access Journals (Sweden)

    Grassian Vicki H

    2011-09-01

    Full Text Available Abstract Background Human exposure to nanoparticles (NPs and environmental bacteria can occur simultaneously. NPs induce inflammatory responses and oxidative stress but may also have immune-suppressive effects, impairing macrophage function and altering epithelial barrier functions. The purpose of this study was to assess the potential pulmonary effects of inhalation and instillation exposure to copper (Cu NPs using a model of lung inflammation and host defense. Methods We used Klebsiella pneumoniae (K.p. in a murine lung infection model to determine if pulmonary bacterial clearance is enhanced or impaired by Cu NP exposure. Two different exposure modes were tested: sub-acute inhalation (4 hr/day, 5 d/week for 2 weeks, 3.5 mg/m3 and intratracheal instillation (24 hr post-exposure, 3, 35, and 100 μg/mouse. Pulmonary responses were evaluated by lung histopathology plus measurement of differential cell counts, total protein, lactate dehydrogenase (LDH activity, and inflammatory cytokines in bronchoalveolar lavage (BAL fluid. Results Cu NP exposure induced inflammatory responses with increased recruitment of total cells and neutrophils to the lungs as well as increased total protein and LDH activity in BAL fluid. Both inhalation and instillation exposure to Cu NPs significantly decreased the pulmonary clearance of K.p.-exposed mice measured 24 hr after bacterial infection following Cu NP exposure versus sham-exposed mice also challenged with K.p (1.4 × 105 bacteria/mouse. Conclusions Cu NP exposure impaired host defense against bacterial lung infections and induced a dose-dependent decrease in bacterial clearance in which even our lowest dose demonstrated significantly lower clearance than observed in sham-exposed mice. Thus, exposure to Cu NPs may increase the risk of pulmonary infection.

  11. Decrease of memory retention in a parasitic wasp: an effect of host manipulation by Wolbachia?

    Science.gov (United States)

    Kishani Farahani, Hossein; Ashouri, Ahmad; Goldansaz, Seyed Hossein; Shapiro, Martin S; Pierre, Jean-Sebastien; van Baaren, Joan

    2017-08-01

    Several factors, such as cold exposure, aging, the number of experiences and viral infection, have been shown to affect learning ability in different organisms. Wolbachia has been found worldwide as an arthropod parasite/mutualist symbiont in a wide range of species, including insects. Differing effects have been identified on physiology and behavior by Wolbachia. However, the effect of Wolbachia infection on the learning ability of their host had never previously been studied. The current study carried out to compare learning ability and memory duration in 2 strains of the parasitoid Trichogramma brassicae: 1 uninfected and 1 infected by Wolbachia. Both strains were able to associate the novel odors with the reward of an oviposition into a host egg. However, the percentage of females that responded to the experimental design and displayed an ability to learn in these conditions was higher in the uninfected strain. Memory duration was longer in uninfected wasps (23.8 and 21.4 h after conditioning with peppermint and lemon, respectively) than in infected wasps (18.9 and 16.2 h after conditioning with peppermint and lemon, respectively). Memory retention increased in response to the number of conditioning sessions in both strains, but memory retention was always shorter in the infected wasps than in the uninfected ones. Wolbachia infection may select for reduced memory retention because shorter memory induces infected wasps to disperse in new environments and avoid competition with uninfected wasps by forgetting cues related to previously visited environments, thus increasing transmission of Wolbachia in new environments. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  12. Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host-parasite interactions.

    Science.gov (United States)

    Tao, Leiling; Gowler, Camden D; Ahmad, Aamina; Hunter, Mark D; de Roode, Jacobus C

    2015-10-22

    Host-parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host-parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host-parasite systems. © 2015 The Author(s).

  13. Harnessing the Effect of Adoptively Transferred Tumor-Reactive T Cells on Endogenous (Host-Derived Antitumor Immunity

    Directory of Open Access Journals (Sweden)

    Yolanda Nesbeth

    2010-01-01

    Full Text Available Adoptive T cell transfer therapy, the ex vivo activation, expansion, and subsequent administration of tumor-reactive T cells, is already the most effective therapy against certain types of cancer. However, recent evidence in animal models and clinical trials suggests that host conditioning interventions tailored for some of the most aggressive and frequent epithelial cancers will be needed to maximize the benefit of this approach. Similarly, the subsets, stage of differentiation, and ex vivo expansion procedure of tumor-reactive T cells to be adoptively transferred influence their in vivo effectiveness and may need to be adapted for different types of cancer and host conditioning interventions. The effects of adoptively transferred tumor-reactive T cells on the mechanisms of endogenous (host-derived antitumor immunity, and how to maximize their combined effects, are further discussed.

  14. Parental effects on the larval performance of a tapeworm in its copepod first host.

    Science.gov (United States)

    Benesh, D P

    2013-08-01

    Parents can influence the phenotype of their offspring through various mechanisms, besides the direct effect of heredity. Such parental effects are little explored in parasitic organisms, perhaps because in many parasites, per capita investment into offspring is low. I investigated whether parental identity, beyond direct genetic effects, could explain variation in the performance of the tapeworm Schistocephalus solidus in its first intermediate host, a copepod. I first determined that two breeding worms could be separated from one another after ~48 h of in vitro incubation and that the isolated worms continued producing outcrossed eggs, that is, rates self-fertilization did not increase after separation. Thus, from a breeding pair, two sets of genetically comparable eggs can be collected that have unambiguous parental identities. In an infection experiment, I found that the development of larval worms tended to vary between the two parental worms within breeding pairs, but infection success and growth rate in copepods did not. Accounting for this parental effect decreased the estimated heritability for development by nearly half. These results suggest that larval performance is not simply a function of a worm's genotype; who mothered or fathered an offspring can also affect offspring fitness, contradicting the perhaps naïve idea that parasites simply produce large quantities of uniformly low-quality offspring. © 2013 The Author. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  15. Percutaneous Penetration - Methodological Considerations

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... 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....

  16. Effects of Intra- and Interpatch Host Density on Egg Parasitism by Three Species of Trichogramma

    Science.gov (United States)

    Grieshop, Matthew J.; Flinn, Paul W.; Nechols, James R.

    2010-01-01

    Host-foraging responses to different intra- and interpatch densities were used to assess three Trichogramma spp. (Hymenoptera: Trichogrammatidae) Trichogramma deion Pinto and Oatman, T. ostriniae Pang and Chen, and T. pretiosum Riley — as potential biological control agents for the Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). Single naïve females were allowed 6 h to forage in Plexiglas arenas with four different spatial arrangements of host eggs, nine single-egg patches), nine four-egg patches, 36 single-egg patches, and 36 four-egg patches. No significant differences were found among species in the number of patches parasitized. As expected, all three species parasitized the most eggs in the 36 four-egg patch treatment and the least in the nine single-egg patch treatment. T. deion parasitized significantly more eggs than T. pretiosum on the nine four-egg patches. T. ostriniae parasitized significantly more patches when intrapatch density was greater, regardless of interpatch density. In contrast, T. deion only parasitized more patches at the greater intrapatch density when the interpatch density was low. Patch density had no effect on T. pretiosum. The spatial pattern of parasitism was more aggregated for T. deion and T. ostriniae in the 36 four-egg patches treatment compared to the 36 single-egg patches treatment. Therefore, intrapatch density was more important than interpatch density for T. ostriniae, and potentially for T. deion, but not for T. pretiosum. T. deion may be the best candidate for augmentative biological control because it parasitized either slightly or significantly more eggs than the other two species in all four treatments. Furthermore, the pattern of parasitism by T. deion in the 36 four-egg patches treatment was the most aggregated among the three species, suggesting a more thorough searching pattern. In contrast, T. pretiosum had the least aggregated pattern of parasitism and therefore may have used a more

  17. The herbaceous landlord: integrating the effects of symbiont consortia within a single host

    Directory of Open Access Journals (Sweden)

    Roo Vandegrift

    2015-11-01

    Full Text Available Plants are typically infected by a consortium of internal fungal associates, including endophytes in their leaves, as well as arbuscular mycorrhizal fungi (AMF and dark septate endophytes (DSE in their roots. It is logical that these organisms will interact with each other and the abiotic environment in addition to their host, but there has been little work to date examining the interactions of multiple symbionts within single plant hosts, or how the relationships among symbionts and their host change across environmental conditions. We examined the grass Agrostis capillaris in the context of a climate manipulation experiment in prairies in the Pacific Northwest, USA. Each plant was tested for presence of foliar endophytes in the genus Epichloë, and we measured percent root length colonized (PRLC by AMF and DSE. We hypothesized that the symbionts in our system would be in competition for host resources, that the outcome of that competition could be driven by the benefit to the host, and that the host plants would be able to allocate carbon to the symbionts in such a way as to maximize fitness benefit within a particular environmental context. We found a correlation between DSE and AMF PRLC across climatic conditions; we also found a fitness cost to increasing DSE colonization, which was negated by presence of Epichloë endophytes. These results suggest that selective pressure on the host is likely to favor host/symbiont relationships that structure the community of symbionts in the most beneficial way possible for the host, not necessarily favoring the individual symbiont that is most beneficial to the host in isolation. These results highlight the need for a more integrative, systems approach to the study of host/symbiont consortia.

  18. Python penetration testing essentials

    CERN Document Server

    Mohit

    2015-01-01

    If you are a Python programmer or a security researcher who has basic knowledge of Python programming and want to learn about penetration testing with the help of Python, this book is ideal for you. Even if you are new to the field of ethical hacking, this book can help you find the vulnerabilities in your system so that you are ready to tackle any kind of attack or intrusion.

  19. Study of Penetration Technology

    Science.gov (United States)

    1976-11-01

    projectile behavior made conclusions from S versus Vo data difficult ta draw. In 1957 Allen, Mayfield, and Morrison (Reference 14) reported what were...plane as the actual nose base, but the tip was forward of the actual tip. The components of and othe point of tangency were xsymt equal tose vapes oern...other hand, attempts to predict the penetration behavior from statically measured soil properties. Deapite the rather strong assumptions involved in

  20. Effects of Non-Susceptible Hosts on the Infection with Trypanosoma cruzi of the Vector Triatoma infestans: an Experimental Model

    Directory of Open Access Journals (Sweden)

    Vázquez Diego P

    1999-01-01

    Full Text Available We tested experimentally the effects of the presence of non-susceptible hosts on the infection with Trypanosoma cruzi of the vector Triatoma infestans. The experiment consisted in two treatments: with chickens, including two chickens (non-susceptible hosts and two infected guinea pigs (susceptible hosts, and without chickens, including only two infected guinea pigs. The hosts were held unrestrained in individual metal cages inside a closed tulle chamber. A total of 200 uninfected T. infestans third instar nymphs were liberated in each replica, collected on day 14, and examined for infection and blood meal sources on day 32-36. The additional presence of chickens relative to infected guinea pigs: (a significantly modified the spatial distribution of bugs; (b increased significantly the likelihoods of having a detectable blood meal on any host and molting to the next instar; (c did not affect the bugs' probability of death by predation; and (d decreased significantly the overall percentage of T. infestans infected with T. cruzi. The bugs collected from inside or close to the guinea pigs' cages showed a higher infection rate (71-88% than those collected from the chickens' cages (22-32%. Mixed blood meals on chickens and guinea pigs were detected in 12-21% of bugs. Although the presence of chickens would decrease the overall percentage of infected bugs in short term experiments, the high rate of host change of T. infestans would make this difference fade out if longer exposure times had been provided.

  1. Finding and recognition of the bovine host by the cercariae of Schistosoma spindale.

    Science.gov (United States)

    Haas, W; Granzer, M; Brockelman, C R

    1990-01-01

    The cercaria of Schistosoma spindale finds and identifies its bovine host with at least five behavioral phases. (1) Dispersal in and selection of midwater and water surface as the microhabitat are achieved by an intermittent swimming behavior with a weak geonegative but not photopositive orientation. (2) Attachments are stimulated by host-specific higher temperatures of the substrate but not by chemical host signals. (3) Remaining of the attached cercariae on the substrate is stimulated by host-specific higher temperatures of the substrate; chemical host signals have no effect. (4) The creeping of the cercariae is directed to the higher temperature in thermal gradients as weak as 0.07 degrees C/mm. Chemical gradients had no effect on the creeping direction. This behavior may enable the cercariae to migrate along hairs to the host's skin surface. (5) Penetrations are stimulated by the free fatty acid fraction of bovine skin-surface lipids. The characteristics of the stimulating fatty acids are the same as those identified for other schistosome species. Higher temperatures of the substrate alone do not stimulate penetrations. S. spindale cercariae do not use as many chemical host cues as stimuli for the identification of their host as do S. mansoni cercariae. S. spindale seems to be adapted to hairy hosts that are infected in shallow, muddy waters. The low host specificity of the cercarial host-finding behavior is compensated by an intimate parasite-snail intermediate host relationship, resulting in a high cercarial production of up to greater than 7,000 cercariae per snail per day.

  2. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...

  3. Effects of cyanobacteria Synechocystis spp. in the host-parasite model Crassostrea gasar–Perkinsus marinus

    Energy Technology Data Exchange (ETDEWEB)

    Queiroga, Fernando Ramos [Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba (Brazil); Marques-Santos, Luis Fernando [Laboratório de Biologia Celular e do Desenvolvimento (LABID), Departamento de Biologia Molecular, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba (Brazil); Hégaret, Hélène [Laboratoire des Sciences de l' Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER, Institut Universitaire Européen de la Mer, Technopôle Brest-Iroise, 29280, Plouzané (France); Sassi, Roberto [Laboratório de Ambientes Recifais e Biotecnologia de Microalgas (LARBIM), Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba (Brazil); Farias, Natanael Dantas; Santana, Lucas Nunes [Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba (Brazil); and others

    2017-06-15

    cyanobacteria; while neither the WCs nor the ECPs modified phagocytosis of the biological particles, zymosan and P. marinus. Our results suggest a negative effect of cyanobacteria from the Synechocystis genus on host immune cells, in contrast to a more beneficial effect on the parasite cell, which could together disrupt the balance of the host-parasite interaction and make oysters more susceptible to P. marinus as well as opportunistic infections.

  4. Does Size Really Matter? The Steric Isotope Effect in a Supramolecular Host?Guest Exchange Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Mugridge, Jeffrey; Bergman, Robert; Raymond, Kenneth

    2010-01-29

    Isotope effects (IEs), which arise from differences in zero point energies (ZPEs) between a parent and isotopically substituted bond, have been used extensively by chemists to probe molecular interactions and reactivity. Due to the anharmonicity of the C-H/D vibrational potential energy function and the lower ZPE of a C-D bond, the average C-D bond length is typically {approx}0.005 {angstrom} shorter than an equivalent C-H bond. It is this difference in size that is often invoked to explain the observation of secondary, inverse kinetic isotope effects (KIEs) in chemical processes which proceed through a sterically strained transition state. This so-called 'steric isotope effect' (SIE) has been observed in processes such as the racemization of ortho-substituted biphenyls[6] and phenanthrenes, ring flipping of cyclophanes, and more recently in the deslipping of rotaxanes, where substitution of the sterically less demanding deuterium for protium results in rate accelerations for these processes. Herein, we use deuterium substitution in a cationic guest molecule to probe the sensitivity limits of the guest exchange process from a highly-charged supramolecular host.

  5. Assessing the effects of climate on host-parasite interactions: a comparative study of European birds and their parasites.

    Directory of Open Access Journals (Sweden)

    Anders Pape Møller

    Full Text Available BACKGROUND: Climate change potentially has important effects on distribution, abundance, transmission and virulence of parasites in wild populations of animals. METHODOLOGY/PRINCIPAL FINDING: Here we analyzed paired information on 89 parasite populations for 24 species of bird hosts some years ago and again in 2010 with an average interval of 10 years. The parasite taxa included protozoa, feather parasites, diptera, ticks, mites and fleas. We investigated whether change in abundance and prevalence of parasites was related to change in body condition, reproduction and population size of hosts. We conducted analyses based on the entire dataset, but also on a restricted dataset with intervals between study years being 5-15 years. Parasite abundance increased over time when restricting the analyses to datasets with an interval of 5-15 years, with no significant effect of changes in temperature at the time of breeding among study sites. Changes in host body condition and clutch size were related to change in temperature between first and second study year. In addition, changes in clutch size, brood size and body condition of hosts were correlated with change in abundance of parasites. Finally, changes in population size of hosts were not significantly related to changes in abundance of parasites or their prevalence. CONCLUSIONS/SIGNIFICANCE: Climate change is associated with a general increase in parasite abundance. Variation in laying date depended on locality and was associated with latitude while body condition of hosts was associated with a change in temperature. Because clutch size, brood size and body condition were associated with change in parasitism, these results suggest that parasites, perhaps mediated through the indirect effects of temperature, may affect fecundity and condition of their hosts. The conclusions were particularly in accordance with predictions when the restricted dataset with intervals of 5-15 years was used, suggesting

  6. Stress responses in Streptococcus species and their effects on the host.

    Science.gov (United States)

    Nguyen, Cuong Thach; Park, Sang-Sang; Rhee, Dong-Kwon

    2015-11-01

    Streptococci cause a variety of diseases, such as dental caries, pharyngitis, meningitis, pneumonia, bacteremia, endocarditis, erysipelas, and necrotizing fasciitis. The natural niche of this genus of bacteria ranges from the mouth and nasopharynx to the skin, indicating that the bacteria will inevitably be subjected to environmental changes during invasion into the host, where it is exposed to the host immune system. Thus, the Streptococcus-host interaction determines whether bacteria are cleared by the host's defenses or whether they survive after invasion to cause serious diseases. If this interaction was to be deciphered, it could aid in the development of novel preventive and therapeutic agents. Streptococcus species possess many virulent factors, such as peroxidases and heat-shock proteins (HSPs), which play key roles in protecting the bacteria from hostile host environments. This review will discuss insights into the mechanism(s) by which streptococci adapt to host environments. Additionally, we will address how streptococcal infections trigger host stress responses; however, the mechanism by which bacterial components modulate host stress responses remains largely unknown.

  7. Host phenology and leaf effects on susceptibility of California bay laurel to Phytophthora ramorum

    Science.gov (United States)

    Steven F. Johnston; Michael F. Cohen; Tamas Torok; Ross K. Meentemeyer; Nathan E. Rank

    2016-01-01

    Spread of the plant pathogen Phytophthora ramorum, causal agent of the forest disease sudden oak death, is driven by a few competent hosts that support spore production from foliar lesions. The relationship between traits of a principal foliar host, California bay laurel (Umbellularia californica), and susceptibility to

  8. Effects of host species and population density on Anoplophora glabripennis flight propensity

    Science.gov (United States)

    Joseph A. Francese; David R. Lance; Baode Wang; Zhichun Xu; Alan J. Sawyer; Victor C. Mastro

    2007-01-01

    Anoplophora glabripennis Motschulsky (Coleoptera: Cerambycidae), the Asian longhorned beetle (ALB) is a pest of hardwoods in its native range of China. While the host range of this pest has been studied extensively, its mechanisms for host selection are still unknown. Our goal was to study the factors influencing movement and orientation of adult ALB...

  9. Effect of joint design and welding type on the flexural strength and weld penetration of Ti-6Al-4V alloy bars.

    Science.gov (United States)

    Simamoto Júnior, Paulo Cézar; Resende Novais, Veridiana; Rodrigues Machado, Asbel; Soares, Carlos José; Araújo Raposo, Luís Henrique

    2015-05-01

    Framework longevity is a key factor for the success of complete-arch prostheses and commonly depends on the welding methods. However, no consensus has been reached on the joint design and welding type for improving framework resistance. The purpose of this study was to assess the effect of different joint designs and welding methods with tungsten inert gas (TIG) or laser to join titanium alloy bars (Ti-6Al-4V). Seventy titanium alloy bar specimens were prepared (3.18 mm in diameter × 40.0 mm in length) and divided into 7 groups (n=10): the C-control group consisting of intact specimens without joints and the remaining 6 groups consisting of specimens sectioned perpendicular to the long-axis and rejoined using an I-, X30-, or X45-shaped joint design with TIG welding (TI, TX30, and TX45) or laser welding (LI, LX30, and LX45). The specimens were tested with 3-point bending. The fracture surfaces were first evaluated with stereomicroscopy to measure the weld penetration area and then analyzed with scanning electron microscopy (SEM). The data were statistically analyzed with 2-way ANOVA and the Tukey post hoc test, 1-way ANOVA and the Dunnett test, and the Pearson correlation test (α=.05). Specimens from the X30 and X45 groups showed higher flexural strength (Pwelded area (Pwelding type. TIG welded groups showed significantly higher flexural strength than the laser groups (PTIG welding also resulted in higher welded areas than laser welding for the I-shaped specimens. No significant differences were found for the weld penetration area in the X45 group, either for laser or TIG welding. SEM analysis showed more pores at the fracture surfaces of the laser specimens. Fracture surfaces indicative of regions of increased ductility were detected for the TIG specimens. TIG welding resulted in higher flexural strength for the joined titanium specimens than laser welding. For both welding methods, X30- and X45-shaped joint designs resulted in higher flexural strength and

  10. Differential Effects of Lichens versus Liverworts Epiphylls on Host Leaf Traits in the Tropical Montane Rainforest, Hainan Island, China

    Directory of Open Access Journals (Sweden)

    Lingyan Zhou

    2014-01-01

    Full Text Available Epiphylls widely colonize vascular leaves in moist tropical forests. Understanding the effects of epiphylls on leaf traits of host plants is critical for understanding ecological function of epiphylls. A study was conducted in a rain forest to investigate leaf traits of the host plants Photinia prunifolia colonized with epiphyllous liverworts and foliicolous lichens as well as those of uncolonized leaves. Our results found that the colonization of lichens significantly decreased leaf water content (LWC, chlorophyll (Chl a and a + b content, and Chl a/b of P. prunifolia but increased Chl b content, while that of liverworts did not affect them as a whole. The variations of net photosynthetic rates (Pn among host leaves colonized with different coverage of lichens before or after removal treatment (a treatment to remove epiphylls from leaf surface were greater than that colonized with liverworts. The full cover of lichens induced an increase of light compensation point (LCP by 21% and a decrease of light saturation point (LSP by 54% for their host leaves, whereas that of liverworts displayed contrary effects. Compared with the colonization of liverworts, lichens exhibited more negative effects on the leaf traits of P. prunifolia in different stages of colonization. The results suggest that the responses of host leaf traits to epiphylls are affected by the epiphyllous groups and coverage, which are also crucial factors in assessing ecofunctions of epiphylls in tropical forests.

  11. The effect of short-range host odor stimuli on host fruit finding and feeding behavior of plum curculio adults (Coleoptera: Curculionidae).

    Science.gov (United States)

    Butkewich, S L; Prokopy, R J

    1993-04-01

    In laboratory assays, we investigated responses of female plum curculios (PCs),Conotrachelus nenuphar (Herbst), to host and nonhost fruit or leaf odor when PCs were crawling on experimental tree branchlets or twigs. In choice tests where test specimens were hung from the ends of a wooden crosspiece, PCs made significantly more visits to host plum fruit than to plum leaves, nonhost tomato fruit, wax models of plum fruit, or blanks (wire). In similar tests, PCs made significantly more visits to plum leaves compared to nonhost maple leaves or to blanks. PCs in test chambers that contained host or nonhost odor were significantly more prone to feed on wax plum models in the presence of odor from host fruit or host leaves compared to odor from nonhost fruit or leaves or a water blank. In choice tests offering alternating cluster types on an apple branchlet, PCs visited leaf clusters bearing a host apple fruit more than leaf clusters without a fruit. In tests to assay the distance at which PCs can detect an individual host fruit, PCs crawled from the central stem of an apple branchlet onto a side stem significantly more often when an apple fruit on a side stem was hung 2 cm from the central stem compared to 4 or 8 cm away. Our combined results suggest that PCs use host fruit odor to locate host fruit at close range.

  12. Effect of the host specific treatment in the phagocytosis of Trypanosoma cruzi blood forms by mouse peritoneal macrophages

    Directory of Open Access Journals (Sweden)

    Eliane Lages-Silva

    1990-12-01

    Full Text Available Single doses of drugs active aginst Trypanosoma cruzi (megazol, nifurtimox and benznidazole induce a rapid clearence of the blood parasites in experimentally infected mice. Furthermore, the in vitro phagocytosis and intracellular destruction by mouse peritoneal macrophage of blood forms collected from the treatment animals is strongly enhanced as compared with parasites from untreated controls. The uptake of the blood forms by macrophages is significantly higher with megazol than with benznidazole and nifurtimox, a finding that concurs with data showing that megazol is also the most active compound in the living host. The possibility that macrophages participate in a synergic effect between the host immune response and chemotherapeutic effect is discussed.

  13. Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits

    Directory of Open Access Journals (Sweden)

    Azucena Canto

    2017-07-01

    Full Text Available We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants.

  14. Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits.

    Science.gov (United States)

    Canto, Azucena; Herrera, Carlos M; Rodriguez, Rosalina

    2017-01-01

    We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants.

  15. Intestinal microbiota-related effects on graft-versus-host disease

    Science.gov (United States)

    Shono, Yusuke; Docampo, Melissa D.; Peled, Jonathan U.; Perobelli, Suelen M.; Jenq, Robert R.

    2016-01-01

    Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an increasingly important treatment for conditions including hematopoietic malignancies and inherited hematopoietic disorders, and is considered to be the most effective form of tumor immunotherapy available to date. However, graft-versus-host disease (GVHD) remains a major source of morbidity and mortality following allo-HSCT, and understanding the mechanisms of GVHD has been highlighted as a key research priority. During development of GVHD, activation of various immune cells, especially donor T cells, leads to damage of target organs including skin, liver, hematopoietic system, and of particular clinical importance, gut. In addition to histocompatibility complex differences between the donor and recipient, pre-transplant conditioning with chemotherapy and irradiation also contributes to GVHD by damaging the gut, resulting in systemic exposure to microbial products normally confined to the intestinal lumen. The intestinal microbiota is a modulator of gastrointestinal immune homeostasis. It also promotes the maintenance of epithelial cells. Recent reports provide growing evidence of the impact of intestinal microbiota on GVHD pathophysiology. This review summarizes current knowledge of changes and effects of intestinal microbiota in the setting of allo-HSCT. We will also discuss potential future strategies of intestinal-microbiota manipulation that might be advantageous in decreasing allo-HSCT related morbidity and mortality. PMID:25812838

  16. Behavioral Effects of the Fungal Pathogen Batrachochytrium Dendrobatidis on the Crayfish Host Procambarus Alleni

    Science.gov (United States)

    Waggett, R. J.; Virgl, E. J.; McMahon, T. A.

    2016-02-01

    The chytrid fungus Batrachochytrium dendrobatidis (Bd) is a parasite implicated in local and global amphibian declines. Although it is considered to be an amphibian specialist, co-occurring species such as the crayfish species Procambarus alleni and Procambarus clarkii have been identified as Bd hosts and potential vectors in the spread and transmission of Bd to amphibians. Procambarus alleni is a freshwater crayfish species native to Florida and popular in the aquarium trade due to its distinctive blue coloration. Although many behavioral and physiological studies have been conducted on the congener, Procambarus clarkii, an introduced species found in many niches throughout the United States, few comparative studies have involved P. alleni. Here, we have quantified the escape behavior kinetics of healthy, lab-reared and wild-caught P. alleni (juvenile and adult) using high speed videography and motion analysis. Kinetic parameters analyzed included velocity, acceleration, net to gross displacement ratios (NGDR), response latency, number of thrusts per response and total distance jumped. Further, we exposed wild-caught P. alleni to cultured Bd and quantified the behavioral effects 24 hours and 1 week following exposure. Data on the survival and behavioral changes of P. alleni could provide insight on the potential toxic effects of Bd and the tendency toward Bd transmission.

  17. An insect-tapeworm model as a proxy for anthelminthic effects in the mammalian host.

    Science.gov (United States)

    Woolsey, Ian David; Fredensborg, Brian L; Jensen, Per M; Kapel, Christian M O; Meyling, Nicolai V

    2015-07-01

    Invertebrate models provide several important advantages over their vertebrate counterparts including fewer legislative stipulations and faster, more cost-effective experimental procedures. Furthermore, various similarities between insect and mammalian systems have been highlighted. To obtain maximum use of invertebrate models in pharmacology, their fidelity as analogues of vertebrate systems requires verification. We utilised a flour beetle (Tenebrio molitor)-tapeworm (Hymenolepis diminuta) model to evaluate the efficacy of known anthelmintic compounds, praziquantel, mebendazole and levamisole against H. diminuta cysticercoid larvae in vitro. Inhibition of cysticercoid activity during the excystation procedure was used as a proxy for worm removal. The effects of the three compounds mirrored their relative efficacy in treatment against adult worms in mammalian systems; however, further study is required to determine the fidelity of this model in relation to dose administered. The model precludes comparison of consecutive daily administration of pharmaceuticals in mammals due to cysticercoids not surviving outside of the host for multiple days. Treatment of beetles in vivo, followed by excystation of cysticercoids postdissection could potentially allow for such comparisons. Further model validation will include analysis of pharmaceutical efficacy in varying H. diminuta isolates and pharmaceutical dilution in solvents other than water. Notwithstanding, our results demonstrate that this model holds promise as a method to efficiently identify promising new cestocidal candidates.

  18. Effects of simulated acidic rain on host-parasite interactions in plant diseases

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, D.S.

    1978-01-01

    The effects of simulated rain acidified with sulfuric acid were studied on five host-parasite systems. Plants were exposed in greenhouse or field to simulated rain of pH 3.2 or pH 6.0 in amounts and intervals common to weather patterns of North Carolina. Simulated acidic rain resulted in: (1) an 86 percent inhibition of the number of telia produced by Cronartium fusiforme on willow oak (Quercus phellos); (2) a 66 percent inhibition in the reproduction of root-knot nematode (Meloidogyne hapla) on field-grown kidney beans (Phaseolus vulgaris ''Red Kidney''); (3) a 29 percent decrease in the percentage of leaf area of field-grown kidney beans affected by Uromyces phaseoli; and (4) either stimulated or inhibited development of halo blight on kidney bean (caused by Pseudomonas phaseolicola), depending upon the stage of the disease cycle in which the treatments were applied. The effect varied as follows: (1) simulated acidic rain applied to plants before inoculation increased disease severity by 42 percent; (2) suspension of bacteria in acidic rain resulted in no infection; and (3) acidic rain applied to plants after infection inhibited disease development by 22 percent. Results suggest that the acidity of rain is an environmental parameter which should be of concern to plant pathologists and agricultural and forest ecologists.

  19. Tick-borne encephalitis transmission risk: its dependence on host population dynamics and climate effects.

    Science.gov (United States)

    Palo, R Thomas

    2014-05-01

    Tick-borne encephalitis (TBE) is a human disease caused by a flavivirus that is spread by ticks (Ixodes ricinus). In 2011 and 2012, the highest TBE incidence ever was recorded in Sweden. It has been proposed that warmer spring temperatures result in higher survival of ticks and thus high incidence of TBE. Here, analyses were done of time series of TBE for 1976-2011 in relation to the North Atlantic Oscillation (NAO), mean summer temperatures, and yearly number of harvested European hare (Lepus europeaus), roe deer (Capreolus capreolus), and red fox (Vulpes vulpes) in the County of Stockholm, the area with most TBE cases in recent years in Sweden. The results show that the winter NAO index or winter temperature has no significant effect on the variation in wildlife numbers harvested or TBE cases over time. Mean summer temperature above 12°C had a slight effect, but a multivariate model revealed that only the numbers of European hare and red fox remained in the model and explained 64.4% of the variation in TBE cases. Ticks do not seem to be as sensitive to climate variations as anticipated, even though that summer temperature has increased by 2°C during the time period studied here. Instead, TBE cases seem to be more dependent on host population dynamics than on climate factors.

  20. Confinement Effects on Host Chain Dynamics in Polymer Nanocomposite Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Kyle J. [Department; Glynos, Emmanouil [Department; Maroulas, Serafeim-Dionysios [Department; Narayanan, Suresh [Advanced; Sakellariou, Georgios [Department; Green, Peter F. [Department; National

    2017-09-07

    Incorporating nanoparticles (NPs) within a polymer host to create polymer nanocomposites (PNCs) while having the effect of increasing the functionality (e.g., sensing, energy conversion) of these materials influences other properties. One challenge is to understand the effects of nanoparticles on the viscosity of nanoscale thick polymer films. A new mechanism that contributes to an enhancement of the viscosity of nanoscale thick polymer/nanoparticle films is identified. We show that while the viscosities of neat homopolymer poly(2-vinylpyridine) (P2VP) films as thin as 50 nm remained the same as the bulk, polymer/nanoparticle films containing P2VP brush-coated gold NPs, spaced 50 nm apart, exhibited unprecedented increases in viscosities of over an order of magnitude. For thicker films or more widely separated NPs, the chain dynamics and viscosities were comparable to the bulk values. These results - NP proximities and suppression of their dynamics - suggest a new mechanism by which the viscosities of polymeric liquids could be controlled for nanoscale applications.

  1. Current concepts in cancer: effects of cancer and cancer treatment on the nutrition of the host

    Energy Technology Data Exchange (ETDEWEB)

    Costa, G.; Donaldson, S.S.

    1979-06-28

    The growth of cancer in man leads to destruction of tissues and alterations of functions. The consequences of this process, culminating in overt cachexia and death, are so varied that cancer has replaced syphilis as the great imitator. Many of the manifestations of cachexia (weakness, anorexia, depletion and translocation of host component, and loss of immunocompetence) resemble malnutrition and are accountable for, in many patients, by poor nutritional intake, neoplastic invasion of the gastrointestinal tract or creation by the tumor of abnormal routes through which nutrients can be lost. The development of cachexia, nevertheless, bears no simple relation to caloric intake, tumor burden, tumor cell type or anatomic site of involvement. Indeed, it has long been apparent that, in many patients succumbing to cancer, if the same lesions were composed of scar tissue rather than neoplastic cells, the affected individuals might not only be alive but in reasonably good health. Distant metabolic effects of cancers have therefore come into focus, are well documented and are known collectively as paraneoplastic syndromes. They imply release by the tumor of chemically identifiable toxic mediators. Recently, a third mechanism has been recognized as an important determinant of cachexia and malnutrition: cancer treatment. As our tools have become more powerful and our philosophies more agressive,the effects of therapy on normal cell populations have become visible. The present paper discusses the most important manifestations of cachexia that resemble malnutrition. Technics of nutritional assessment and intervention that have proved successful in patients with cancer are also briefly discussed.

  2. Are ant feces nutrients for plants? A metabolomics approach to elucidate the nutritional effects on plants hosting weaver ants

    DEFF Research Database (Denmark)

    Vidkjær, Nanna Hjort; Wollenweber, Bernd; Gislum, René

    2015-01-01

    interactions involving other ant species that have demonstrated the transfer of nutrients from ants to plants. In this 7-months study, a GC–MS-based metabolomics approach along with an analysis of total nitrogen and carbon levels was used to study metabolic changes in ant-hosting Coffea arabica plants compared...... with control plants. The results showed elevated levels of total nitrogen, amino acids, fatty acids, caffeine, and secondary metabolites of the phenylpropanoid pathway in leaves from ant-hosting plants. Minor effects were observed for sugars, whereas little or no effect was observed for organic acids, despite......Weaver ants (genus Oecophylla) are tropical carnivorous ant species living in high numbers in the canopies of trees. The ants excrete copious amounts of fecal matter on leaf surfaces, and these feces may provide nutrients to host trees. This hypothesis is supported by studies of ant-plant...

  3. Host and parasite thermal ecology jointly determine the effect of climate warming on epidemic dynamics.

    Science.gov (United States)

    Gehman, Alyssa-Lois M; Hall, Richard J; Byers, James E

    2018-01-23

    Host-parasite systems have intricately coupled life cycles, but each interactor can respond differently to changes in environmental variables like temperature. Although vital to predicting how parasitism will respond to climate change, thermal responses of both host and parasite in key traits affecting infection dynamics have rarely been quantified. Through temperature-controlled experiments on an ectothermic host-parasite system, we demonstrate an offset in the thermal optima for survival of infected and uninfected hosts and parasite production. We combine experimentally derived thermal performance curves with field data on seasonal host abundance and parasite prevalence to parameterize an epidemiological model and forecast the dynamical responses to plausible future climate-warming scenarios. In warming scenarios within the coastal southeastern United States, the model predicts sharp declines in parasite prevalence, with local parasite extinction occurring with as little as 2 °C warming. The northern portion of the parasite's current range could experience local increases in transmission, but assuming no thermal adaptation of the parasite, we find no evidence that the parasite will expand its range northward under warming. This work exemplifies that some host populations may experience reduced parasitism in a warming world and highlights the need to measure host and parasite thermal performance to predict infection responses to climate change.

  4. Effects of host injury on susceptibility of marine reef fishes to ectoparasitic gnathiid isopods

    Science.gov (United States)

    Jenkins, William G.; Demopoulos, Amanda W.J.; Sikkel, Paul C.

    2017-01-01

    The importance of the role that parasites play in ecological communities is becoming increasingly apparent. However much about their impact on hosts and thus populations and communities remains poorly understood. A common observation in wild populations is high variation in levels of parasite infestation among hosts. While high variation could be due to chance encounter, there is increasing evidence to suggest that such patterns are due to a combination of environmental, host, and parasite factors. In order to examine the role of host condition on parasite infection, rates of Gnathia marleyi infestation were compared between experimentally injured and uninjured fish hosts. Experimental injuries were similar to the minor wounds commonly observed in nature. The presence of the injury significantly increased the probability of infestation by gnathiids. However, the level of infestation (i.e., total number of gnathiid parasites) for individual hosts, appeared to be unaffected by the treatment. The results from this study indicate that injuries obtained by fish in nature may carry the additional cost of increased parasite burden along with the costs typically associated with physical injury. These results suggest that host condition may be an important factor in determining the likelihood of infestation by a common coral reef fish ectoparasite, G. marleyi.

  5. Effect of sexual segregation on host-parasite interaction: model simulation for abomasal parasite dynamics in alpine ibex (Capraibex).

    Science.gov (United States)

    Ferrari, Nicola; Rosà, Roberto; Lanfranchi, Paolo; Ruckstuhl, Kathreen E

    2010-09-01

    We investigated whether sexual segregation might affect parasite transmission and host dynamics, hypothesising that if males are the more heavily infected sex and more responsible for the transmission of parasite infections, female avoidance of males and the space they occupy could reduce infection rates. A mathematical model, simulating the interaction between abomasal parasites and a hypothetical alpine ibex (Capraibex) host population composed of its two sexes, was developed to predict the effect of different degrees of sexual segregation on parasite intensity and on host abundance. The results showed that when females tended to be segregated from males, and males were distributed randomly across space, the impact of parasites was the lowest, resulting in the highest host abundance, with each sex having the lowest parasite intensity. The predicted condition that minimises the impact of parasites in our model was the one closest to that observed in nature where females actively seek out the more segregated sites while males are less selective in their ranging behaviour. The overlapping of field observation with the predicted optimal strategy lends support to our idea that there might be a connection between parasite transmission and sexual segregation. Our simulations provide the biological boundaries of host-parasite interaction needed to determine a parasite-mediated effect on sexual segregation and a formalised null hypothesis against which to test future field experiments. Copyright (c) 2010 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  6. Electrical penetration graph studies to investigate the effects of cyantraniliprole on feeding behavior of Myzus persicae (Hemiptera: Aphididae) on Capsicum annuum.

    Science.gov (United States)

    Jacobson, Alana L; Kennedy, George G

    2014-05-01

    The anthranilic diamide insecticide cyantraniliprole has been shown to suppress aphid and whitefly populations as well as reduce transmission of plant viruses by thrips and whiteflies when taken up systemically by the plant. In this study, electrical penetration graphing (EPG) was used to compare effects of cyantraniliprole on feeding behavior of Myzus persicae with those of the neonicotinoid insecticide imidacloprid applied as a soil drench to pepper plants two-, six-, and ten-days post-treatment. Significant reductions in the total amount of time spent probing, mean number of phloem feeding events, and mean number of intracellular punctures were observed on both cyantraniliprole- and imidacloprid-treated plants, compared to aphids that fed on plants treated only with water. Imidacloprid treatment also caused a significant reduction in the total number of probes relative to the water treated control. The effects of cyantraniliprole were statistically significant only in assays conducted at ten-days post-treatment, whereas the effects of imidacloprid on aphid feeding were significant in assays conducted at two-, six-, and ten-days post-treatment. These findings document significant effects of cyantraniliprole on feeding by Myzus persicae. © 2013 Society of Chemical Industry.

  7. Penetrating ureteral trauma

    Directory of Open Access Journals (Sweden)

    Gustavo P. Fraga

    2007-04-01

    Full Text Available OBJECTIVE: The purpose of this series is to report our experience in managing ureteral trauma, focusing on the importance of early diagnosis, correct treatment, and the impact of associated injuries on the management and morbid-mortality. MATERIALS AND METHODS: From January 1994 to December 2002, 1487 laparotomies for abdominal trauma were performed and 20 patients with ureteral lesions were identified, all of them secondary to penetrating injury. Medical charts were analyzed as well as information about trauma mechanisms, diagnostic routine, treatment and outcome. RESULTS: All patients were men. Mean age was 27 years. The mechanisms of injury were gunshot wounds in 18 cases (90% and stab wounds in two (10%. All penetrating abdominal injuries had primary indication of laparotomy, and neither excretory urography nor computed tomography were used in any case before surgery. The diagnosis of ureteric injury was made intra-operatively in 17 cases (85%. Two ureteral injuries (10% were initially missed. All patients had associated injuries. The treatment was dictated by the location, extension and time necessary to identify the injury. The overall incidence of complications was 55%. The presence of shock on admission, delayed diagnosis, Abdominal Trauma Index > 25, Injury Severity Score > 25 and colon injuries were associated to a high complication rate, however, there was no statistically significant difference. There were no mortalities in this group. CONCLUSIONS: A high index of suspicion is required for diagnosis of ureteral injuries. A thorough exploration of all retroperitoneal hematoma after penetrating trauma should be an accurate method of diagnosis; even though it failed in 10% of our cases.

  8. Penetrating Fire Extinguisher

    Science.gov (United States)

    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.

  9. Parasite host range and the evolution of host resistance

    NARCIS (Netherlands)

    Gorter, F.A.; Hall, A.R.; A., Buckling; P.D., Scanlan

    2015-01-01

    Parasite host range plays a pivotal role in the evolution and ecology of hosts
    and the emergence of infectious disease. Although the factors that promote
    host range and the epidemiological consequences of variation in host range
    are relatively well characterized, the effect of parasite

  10. Invasive insect effects on nitrogen cycling and host physiology are not tightly linked.

    Science.gov (United States)

    Rubino, Lucy; Charles, Sherley; Sirulnik, Abby G; Tuininga, Amy R; Lewis, James D

    2015-02-01

    Invasive insects may dramatically alter resource cycling and productivity in forest ecosystems. Yet, although responses of individual trees should both reflect and affect ecosystem-scale responses, relationships between physiological- and ecosystem-scale responses to invasive insects have not been extensively studied. To address this issue, we examined changes in soil nitrogen (N) cycling, N uptake and allocation, and needle biochemistry and physiology in eastern hemlock (Tsuga canadensis (L) Carr) saplings, associated with infestation by the hemlock woolly adelgid (HWA) (Adelges tsugae Annand), an invasive insect causing widespread decline of eastern hemlock in the eastern USA. Compared with uninfested saplings, infested saplings had soils that exhibited faster nitrification rates, and more needle (15)N uptake, N and total protein concentrations. However, these variables did not clearly covary. Further, within infested saplings, needle N concentration did not vary with HWA density. Light-saturated net photosynthetic rates (Asat) declined by 42% as HWA density increased from 0 to 3 adelgids per needle, but did not vary with needle N concentration. Rather, Asat varied with stomatal conductance, which was highest at the lowest HWA density and accounted for 79% of the variation in Asat. Photosynthetic light response did not differ among HWA densities. Our results suggest that the effects of HWA infestation on soil N pools and fluxes, (15)N uptake, needle N and protein concentrations, and needle physiology may not be tightly coupled under at least some conditions. This pattern may reflect direct effects of the HWA on N uptake by host trees, as well as effects of other scale-dependent factors, such as tree hydrology, affected by HWA activity. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Host-plant-mediated effects of Nadefensin on herbivore and pathogen resistance in Nicotiana attenuata

    Directory of Open Access Journals (Sweden)

    Baldwin Ian T

    2008-10-01

    Full Text Available Abstract Background The adage from Shakespeare, "troubles, not as single spies, but in battalions come," holds true for Nicotiana attenuata, which is commonly attacked by both pathogens (Pseudomonas spp. and herbivores (Manduca sexta in its native habitats. Defense responses targeted against the pathogens can directly or indirectly influence the responses against the herbivores. Nadefensin is an effective induced defense gene against the bacterial pathogen Pseudomonas syringae pv tomato (PST DC3000, which is also elicited by attack from M. sexta larvae, but whether this defense protein influences M. sexta's growth and whether M. sexta-induced Nadefensin directly or indirectly influences PST DC3000 resistance are unknown. Results M. sexta larvae consumed less on WT and on Nadefensin-silenced N. attenuata plants that had previously been infected with PST DC3000 than on uninfected plants. WT plants infected with PST DC3000 showed enhanced resistance to PST DC3000 and decreased leaf consumption by M. sexta larvae, but larval mass gain was unaffected. PST DC3000-infected Nadefensin-silenced plants were less resistant to subsequent PST DC3000 challenge, and on these plants, M. sexta larvae consumed less and gained less mass. WT and Nadefensin-silenced plants previously damaged by M. sexta larvae were better able to resist subsequent PST DC3000 challenges than were undamaged plants. Conclusion These results demonstrate that Na-defensin directly mediates defense against PST DC3000 and indirectly against M. sexta in N. attenuata. In plants that were previously infected with PST DC3000, the altered leaf chemistry in PST DC3000-resistant WT plants and PST DC3000-susceptible Nadefensin-silenced plants differentially reduced M. sexta's leaf consumption and mass gain. In plants that were previously damaged by M. sexta, the combined effect of the altered host plant chemistry and a broad spectrum of anti-herbivore induced metabolomic responses was more

  12. Older Is Not Wiser, Immunologically Speaking: Effect of Aging on Host Response to Clostridium difficile Infections.

    Science.gov (United States)

    Shin, Jae Hyun; High, Kevin P; Warren, Cirle A

    2016-07-01

    Clostridium difficile infection (CDI) is the most common cause of antibiotic-associated diarrhea and a significant burden on the health care system. Aging has been identified in the literature as a risk factor for CDI as well as adverse outcome from CDI. Although this effect of advanced age on CDI could be partially explained by clinical factors associated with aging, biologic factors are important. Innate immune system, responsible for immediate response to acute infections, plays a major role in CDI pathogenesis. Impairment in function of innate immunity with aging, demonstrated in other infection models, may lead to worse outcome with CDI. C. difficile toxin-specific antibody response protects the host against initial and recurrent infections as shown in observational studies and clinical trial. Effect of aging on antibody response to CDI has not been demonstrated, but the results from vaccine studies in other infections suggest a negative effect on humoral immunity from aging. Although intestinal microbiota from healthy people confers resistance to CDI by preventing C. difficile colonization, changes in composition of microbiota with aging may affect that resistance and increase risk for CDI. There are also age-associated changes in physiology, especially of the gastrointestinal tract, that may play a role in CDI risk and outcomes. In this review, we will first discuss the epidemiology of CDI in the elderly people, then the alteration in innate immunity, humoral response, and microbiota that increases susceptibility to CDI and severe disease and lastly, the physiological and functional changes that may modify outcomes of infection. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Emerging dangers: deadly effects of an emergent parasite in a new pollinator host.

    Science.gov (United States)

    Graystock, Peter; Yates, Kathryn; Darvill, Ben; Goulson, Dave; Hughes, William O H

    2013-10-01

    There is growing concern about the threats facing many pollinator populations. Emergent diseases are one of the major threats to biodiversity and a microsporidian parasite, Nosema ceranae, has recently jumped host from the Asian to the Western honeybee, spreading rapidly worldwide, and contributing to dramatic colony losses. Bumblebees are ecologically and economically important pollinators of conservation concern, which are likely exposed to N. ceranae by sharing flowers with honeybees. Whilst a further intergeneric jump by N. ceranae to infect bumblebees would be potentially serious, its capacity to do this is unknown. Here we investigate the prevalence of N. ceranae in wild bumblebees in the UK and determine the infectivity of the parasite under controlled conditions. We found N. ceranae in all seven wild bumblebee species sampled, and at multiple sites, with many of the bees having spores from this parasite in their guts. When we fed N. ceranae spores to bumblebees under controlled conditions, we confirmed that the parasite can infect bumblebees. Infections spread from the midgut to other tissues, reduced bumblebee survival by 48% and had sub-lethal effects on behaviour. Although spore production appeared lower in bumblebees than in honeybees, virulence was greater. The parasite N. ceranae therefore represents a real and emerging threat to bumblebees, with the potential to have devastating consequences for their already vulnerable populations. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Confinement Effects on Host Chain Dynamics in Polymer Nanocomposite Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Kyle J. [Department; Glynos, Emmanouil [Department; Maroulas, Serafeim-Dionysios [Department; Narayanan, Suresh [Advanced; Sakellariou, Georgios [Department; Green, Peter F. [Department; National

    2017-09-06

    Incorporating nanoparticles (NPs) within a polymer host to create polymer nanocomposites (PNCs) while having the effect of increasing the functionality (e.g.: sensing, energy conversion) of these materials, introduces additional complications with regard to the processing-morphology-function behavior. A primary challenge is to understand and control the viscosity of a PNC with decreasing film thickness confinement for nanoscale applications. Using a combination of X-ray photon correlation spectroscopy (XPCS) and X-ray standing wave based resonance enhanced XPCS to study the dynamics of neat poly-2-vinyl pyridine (P2VP) chains and the nanoparticle dynamics, respectively, we identified a new mechanism that dictates the viscosity of PNC films in the nanoscale regime. We show that while the viscosities of neat P2VP films as thin as 50 nm remained the same as the bulk, PNC films containing P2VP brush-coated gold NPs, spaced 50 nm apart, exhibited unprecedented increases in viscosities of over an order of magnitude. For thicker films or more widely separated NPs, the chain dynamics and viscosities were equal to the bulk values. These results -NP proximities and suppression of their dynamics -suggest a new mechanism by which the viscosities of polymeric liquids could be controlled for 2D and 3D nanoscale applications.

  15. The effect of gluten on the host-microbial metabolism assessed by urinary metabolomics

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Frandsen, Henrik Lauritz; Gøbel, Rikke Juul

    A gluten-free diet clearly improves the life of patients with celiac disease, but the scientific evidence supporting possible health benefits of a gluten-free diet for non-celiac adults is limited. Therefore, as urine reflects the host and gut microbial metabolism, the study aimed to assess...... the long-term metabolic effect of gluten on the urine metabolome of non-celiac individuals by a cross-over intervention study (gluten-poor and gluten rich, respectively) using a non-targeted metabolomics approach. Fifty-one non-celiac adult participants (30 female, 21 male) were randomized to either...... a gluten-rich (21.6±5.7g/day) or a gluten-poor (~1g/day) diet for 8 weeks, crossing over to the other diet after 6 weeks washout. Urine samples were standardised collected at the beginning and end of each diet intervention period and were analysed by gas chromatography mass spectrometry (GC-MS) and liquid...

  16. Effects of formulation and host nematode density on the ability of in vitro-produced pasteuria endospores to control its host Belonolaimus longicaudatus.

    Science.gov (United States)

    Luc, John E; Pang, Wenjing; Crow, William T; Giblin-Davis, Robin M

    2010-06-01

    The effect of nematode population density at the time of application and formulations of in vitro-produced Pasteuria spp. endospores on the final population density of Belonolaimus longicaudatus was studied in an 84-d-long pot bioassay. The experiment utilized a factorial design consisting of 30 or 300 B. longicaudatus /100 cm(3) of sandy soil and three formulations of in vitro-produced Pasteuria spp. endospores (nontreated, granular, or liquid). No differences were observed in percent endospore attachment between nematode inoculum levels during either trial. Granular and liquid formulations of in vitro-produced endospores suppressed nematode population densities by 22% and 59% in the first trial and 20% and 63% in the second, respectively compared with the nontreated control. The liquid formulation increased percent endospore attachment by 147% and 158%, respectively, compared with the granular formulation. The greatest root retention by the host plant was observed at the lower B. longicaudatus inoculation level following application of the liquid formulation. While both the granular and liquid formulations reduced B. longicaudatus population densities in the soil, the liquid spore suspension was most effective.

  17. Mannose-specific interactions of Lactobacillus plantarum in the intestine : bacterial genes, molecular host responses and potential probiotic effects

    NARCIS (Netherlands)

    Pretzer, G.

    2008-01-01

    One potential mechanism by which probiotic microorganisms may exert beneficial health effects to the host is the inhibition of intestinal infections by competitive exclusion of pathogenic bacteria. This concept may also be applicable for mannose-specific adhesion to the epithelial surface, which has

  18. Effect of Heat Input During Disk Laser Bead-On-Plate Welding of Thermomechanically Rolled Steel on Penetration Characteristics and Porosity Formation in the Weld Metal

    Directory of Open Access Journals (Sweden)

    Lisiecki A.

    2016-03-01

    Full Text Available The paper presents a detailed analysis of the influence of heat input during laser bead-on-plate welding of 5.0 mm thick plates of S700MC steel by modern Disk laser on the mechanism of steel penetration, shape and depth of penetration, and also on tendency to weld porosity formation. Based on the investigations performed in a wide range of laser welding parameters the relationship between laser power and welding speed, thus heat input, required for full penetration was determined. Additionally the relationship between the laser welding parameters and weld quality was determined.

  19. Effects of host migration, diversity and aquaculture on sea lice threats to Pacific salmon populations.

    Science.gov (United States)

    Krkosek, Martin; Gottesfeld, Allen; Proctor, Bart; Rolston, Dave; Carr-Harris, Charmaine; Lewis, Mark A

    2007-12-22

    Animal migrations can affect disease dynamics. One consequence of migration common to marine fish and invertebrates is migratory allopatry-a period of spatial separation between adult and juvenile hosts, which is caused by host migration and which prevents parasite transmission from adult to juvenile hosts. We studied this characteristic for sea lice (Lepeophtheirus salmonis and Caligus clemensi) and pink salmon (Oncorhynchus gorbuscha) from one of the Canada's largest salmon stocks. Migratory allopatry protects juvenile salmon from L. salmonis for two to three months of early marine life (2-3% prevalence). In contrast, host diversity facilitates access for C. clemensi to juvenile salmon (8-20% prevalence) but infections appear ephemeral. Aquaculture can augment host abundance and diversity and increase parasite exposure of wild juvenile fish. An empirically parametrized model shows high sensitivity of salmon populations to increased L. salmonis exposure, predicting population collapse at one to five motile L. salmonis per juvenile pink salmon. These results characterize parasite threats of salmon aquaculture to wild salmon populations and show how host migration and diversity are important factors affecting parasite transmission in the oceans.

  20. Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize.

    Science.gov (United States)

    Jordaan, E M; De Waele, D

    1988-10-01

    The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae.

  1. Effects of host plants on digestive enzymatic activities and some components involved in intermediary metabolism of Chrysodeixis chalcites (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    M. Mardani-Talaee

    2014-12-01

    Full Text Available Chrysodeixis chalcites (Esper is a serious pest that causes devastating damages in infested areas to many fruits, vegetables, ornamental crops and weeds. In the current study, effects of three host plants including lemon balm (Melissa officinalis L.; corn (Zea mays L. and dill (Anethum graveolens L. were determined on digestive enzyme activities and intermediary metabolism of C. chalcites larvae. The highest activities of α-amylase, glucosidases and specific proteases were observed in the larvae fed on dill. Our results showed that C. chalcites larvae had the highest TAG-lipase activity on corn in comparison with other host plants. Significant differences were found among enzymatic activities of acid (ACP and alkaline phosphatases, aspartate aminotransferases and lactate dehydrogenase (LDH in the haemolymph of C. chalcites larvae reared on lemon balm, corn and dill, respectively, although activity of alanine aminotransferase showed no statistically significant differences among different host plants. The enzymatic activity of ACP significantly decreased on dill in comparison with lemon balm and corn. The activity of LDH significantly increased on dill compared with other host plants. These results revealed that dill (A. graveolens is the most appropriate host plant for larvae of C. chalcites as evidenced by the highest digestive enzyme activities and intermediary metabolism.

  2. Penetration resistance according to penetration rate, cone base size and different soil conditions

    Directory of Open Access Journals (Sweden)

    Daniel Dias Valadão Junior

    2014-06-01

    Full Text Available This study aimed to evaluate the effect of penetration rate and the size of the cone base on the resistance to penetration under different soil moistures and soil bulk density. The experimental design was completely randomized in a 4x2x2x2 factorial arrangement, with the factors, soil bulk density of 1.0; 1.2; 1.4 and 1.6 Mg m-3, soil moisture at the evaluation of 0.16 and 0.22 kg kg-1, penetration rates of 0.166 and 30 mm s-1 and areas of the cone base of 10.98 and 129.28 mm² resulting in 32 treatments with 8 replicates. To ensure greater uniformity and similarity to field conditions, samples passed through cycles of wetting and drying. Only the interaction of the four factors was not significant. Resistance values varied with the density of the soil, regardless of moisture and penetration rate. Soil penetration resistance was influenced by the size of the cone base, with higher values for the smallest base independent of moisture and soil bulk density. The relationship between resistance to penetration and moisture is not always linear, once it is influenced by soil bulk density. Reduction in the area of the cone leads to an increase in the soil resistance to penetration.

  3. Impact of Wind Shear and Tower Shadow Effects on Power System with Large Scale Wind Power Penetration

    DEFF Research Database (Denmark)

    Hu, Weihao; Su, Chi; Chen, Zhe

    2011-01-01

    presents a simulation model of a variable speed wind farm with permanent magnet synchronous generators (PMSGs) and fullscale back-to-back converters in the simulation tool of DIgSILENT/PowerFactory. In this paper, the impacts of wind shear and tower shadow effects on the small signal stability of power...

  4. Independent regulation of reovirus membrane penetration and apoptosis by the mu1 phi domain.

    Directory of Open Access Journals (Sweden)

    Pranav Danthi

    2008-12-01

    Full Text Available Apoptosis plays an important role in the pathogenesis of reovirus encephalitis. Reovirus outer-capsid protein mu1, which functions to penetrate host cell membranes during viral entry, is the primary regulator of apoptosis following reovirus infection. Ectopic expression of full-length and truncated forms of mu1 indicates that the mu1 phi domain is sufficient to elicit a cell death response. To evaluate the contribution of the mu1 phi domain to the induction of apoptosis following reovirus infection, phi mutant viruses were generated by reverse genetics and analyzed for the capacity to penetrate cell membranes and elicit apoptosis. We found that mutations in phi diminish reovirus membrane penetration efficiency by preventing conformational changes that lead to generation of key reovirus entry intermediates. Independent of effects on membrane penetration, amino acid substitutions in phi affect the apoptotic potential of reovirus, suggesting that phi initiates apoptosis subsequent to cytosolic delivery. In comparison to wild-type virus, apoptosis-defective phi mutant viruses display diminished neurovirulence following intracranial inoculation of newborn mice. These results indicate that the phi domain of mu1 plays an important regulatory role in reovirus-induced apoptosis and disease.

  5. Effect of endophytic Bacillus cereus ERBP inoculation into non-native host: Potentials and challenges for airborne formaldehyde removal.

    Science.gov (United States)

    Khaksar, Gholamreza; Treesubsuntorn, Chairat; Thiravetyan, Paitip

    2016-10-01

    Phytoremediation could be a cost-effective, environmentally friendly approach for the treatment of indoor air. However, some drawbacks still dispute the expediency of phytotechnology. Our objectives were to investigate the competency of plant growth-promoting (PGP) endophytic Bacillus cereus ERBP (endophyte root blue pea), isolated from the root of Clitoria ternatea, to colonize and stabilize within Zamioculcas zamiifolia and Euphorbia milii as non-native hosts without causing any disease or stress symptoms. Moreover, the impact of B. cereus ERBP on the natural shoot endophytic community and for the airborne formaldehyde removal capability of non-native hosts was assessed. Non-native Z. zamiifolia was effectively inoculated with B. cereus ERBP through soil as the most efficient method of endophyte inoculation. Denaturing gradient gel electrophoresis profiling of the shoot endophytic community verified the colonization and stability of B. cereus ERBP within its non-native host during a 20-d fumigation period without interfering with the natural shoot endophytic diversity of Z. zamiifolia. B. cereus ERBP conferred full protection to its non-native host against formaldehyde phytotoxicity and enhanced airborne formaldehyde removal of Z. zamiifolia whereas non-inoculated plants suffered from formaldehyde phytotoxicity because their natural shoot endophytic community was detrimentally affected by formaldehyde. In contrast, B. cereus ERBP inoculation into non-native E. milii deteriorated airborne formaldehyde removal of the non-native host (compared to a non-inoculated one) as B. cereus ERBP interfered with natural shoot endophytic community of E. milii, which caused stress symptoms and stimulated ethylene biosynthesis. Non-native host inoculation with PGP B. cereus ERBP could bear potentials and challenges for airborne formaldehyde removal. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  6. Effects of simulated rain acidified with sulfuric acid on host-parasite interactions

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, D.S.

    1977-01-01

    Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The effects of simulated rain acidified with sulfuric acid were studied on several host-parasite systems. Plants were exposed in greenhouse or field to simulated rain of pH 3.2 +- 0.1 or pH 6.0 +- 0.2. Simulated rain of pH 3.2 resulted in: (1) an 86% inhibition in telia production of Cronartium fusiforme on Quercus phellos; (2) a 66% inhibition of reproduction of Meloidogyne hapla on field-grown Phaseolus vulgaris; (3) a 10% decrease in the severity of Uromyces phaseoli on field-grown Phaseolus vulgaris; and (4) an inhibition of Rhizobium nodulation of Phaseolus vulgaris and Glycine max by an average of 73%. Effects on halo blight of kidney bean (caused by Pseudomonas phaseolicola) depended upon the segment of the disease cycle in which the rain occurred: simulated rain of pH 3.2 applied to plants before inoculation stimulated disease development; suspension of inoculum in rain of pH 3.2 decreased inoculum potential; and rain of pH 3.2 applied to plants after infection inhibited disease development. Scanning electron microscopy of epicuticular waxes on leaves of Quercus phellos and Phaseolus vulgaris showed marked erosion of those surfaces by rain of pH 3.2, indicating possible influences on the structure and function of plant cuticles. These results suggest that the acidity of rain is a new parameter of environmental concern, and underline the need for study of the consequences of prolonged exposure of both agronomic and natural ecosystems to this stress factor.

  7. Effects of simulated rain acidified with sulfuric acid on host-parasite interactions

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, D.S.

    1976-01-01

    Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The effects of simulated rain acidified with sulfuric acid were studied on several host-parasite systems. Plants were exposed, in greenhouse or field, to simulated rain of pH 3.2+ or - 0.1 or pH 6.0 + or - 0.2. Simulated rain of pH 3.2 resulted in: an 86% inhibition in telia production of Cronartium fusiforme on Quercus phellos; a 66% inhibition of reproduction of Meloidogyne hapla on field-grown Phaseolus vulgaris; a 10% decrease in the severity of Uromyces phaseoli on field-grown Phaseolus vulgaris; and an inhibition of Rhizobium nodulation of Phaseolus vulgaris and Glycine max by an average of 73%. Effects on halo blight of kidney bean (caused by Pseudomonas phaseolicola) depended upon the segment of the disease cycle in which the rain occurred: simulated rain of pH 3.2 applied to plants before inoculation stimulated disease development; suspension of inoculum in ''rain'' of pH 3.2 decreased inoculum potential; and (c) ''rain'' of pH 3.2 applied to plants after infection inhibited disease development. Scanning electron microscopy of epicuticular waxes on leaves of Quercus phellos and Phaseolus vulgaris showed marked erosion of those surfaces by rain of pH 3.2, indicating possible influences on the structure and function of plant cuticles.

  8. Effect of Ramping Requirement and Price Cap on Energy Price in a System with High Wind Penetration

    OpenAIRE

    Martin, Sebastián; Smeers, Yves; Aguado, José de

    2015-01-01

    The European power market is currently retiring or mothballing large capacities of conventional plants, and at the same time incorporating a significant amount of non-dispatchable renewable generation, in particular wind. We analyse the mothballing process (and the resulting system) and study how they are affected by a price cap implemented in the energy only market, and by a possible implementation of ramping products in the system. Sebastian Martin, Yves Smeers, and Jose Aguado. Effect o...

  9. Ballistic-type field penetration into metals illustrated by high- and low-frequency size-effect measurements in silver

    DEFF Research Database (Denmark)

    Gantmakher, V. F.; Lebech, Jens; Bak, Christen Kjeldahl

    1979-01-01

    structure of the field is eliminated because it takes a finite time for an electron to pass the effective region of the trajectory when compared to the time variation of the applied field. Hence only the field between the splash positions remains. The role of different types of trajectories under...... these conditions are discussed on the basis of Pippard's ineffectiveness concept. The Fermi velocities along the belly orbit (B→∥[001]) in silver are extracted from the high-frequency spectra....

  10. The Effect of Anthelmintic Treatment on Coccidia Oocyst Shedding in a Wild Mammal Host with Intermittent Cestode Infection

    Directory of Open Access Journals (Sweden)

    Radovan Václav

    2014-01-01

    Full Text Available While hosts are routinely exploited by a community of parasite species, the principles governing host responses towards parasites are unclear. Identifying the health outcomes of coinfections involving helminth macroparasites and microparasites is one area of importance for public and domestic animal health. For instance, it is controversial how deworming programmes affect incidence and severity of such important microparasite diseases as malaria. One problem is that most study systems involve domestic and laboratory animals with conditions hardly comparable to those of free-living animals. Here, we study the effect of anthelmintic treatment on coccidia infection intensity in wild Alpine marmots, M. marmota. Our results lend support to the hypothesis that helminth infection has a positive effect on concurrent microparasite infection. However, our work also points to the fact that within-host interactions between helminths and microparasites are context-dependent and can turn to negative ones once helminth burdens increase. Our study suggests that coccidia benefit from intermittent helminth infection in marmots due to the protective effects of helminth infection only during the early phase of the host’s active season. Also, the marmot’s response towards coccidia infection appears optimal only under no helminth infection when the host immune response towards coccidia would not be compromised, thereby pointing to the importance of regular intestinal helminth elimination by marmots just before hibernation.

  11. Myelopotentiating effect of curcumin in tumor-bearing host: Role of bone marrow resident macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Vishvakarma, Naveen Kumar; Kumar, Anjani; Kumar, Ajay; Kant, Shiva [School of Biotechnology, Banaras Hindu University, Varanasi-221 005, U.P. (India); Bharti, Alok Chandra [Division of Molecular Oncology, Institute of Cytology and Preventive Oncology, Noida, UP (India); Singh, Sukh Mahendra, E-mail: sukhmahendrasingh@yahoo.com [School of Biotechnology, Banaras Hindu University, Varanasi-221 005, U.P. (India)

    2012-08-15

    The present investigation was undertaken to study if curcumin, which is recognized for its potential as an antineoplastic and immunopotentiating agent, can also influence the process of myelopoiesis in a tumor-bearing host. Administration of curcumin to tumor-bearing host augmented count of bone marrow cell (BMC) accompanied by an up-regulated BMC survival and a declined induction of apoptosis. Curcumin administration modulated expression of cell survival regulatory molecules: Bcl2, p53, caspase-activated DNase (CAD) and p53-upregulated modulator of apoptosis (PUMA) along with enhanced expression of genes of receptors for M-CSF and GM-CSF in BMC. The BMC harvested from curcumin-administered hosts showed an up-regulated colony forming ability with predominant differentiation into bone marrow-derived macrophages (BMDM), responsive for activation to tumoricidal state. The number of F4/80 positive bone marrow resident macrophages (BMM), showing an augmented expression of M-CSF, was also augmented in the bone marrow of curcumin-administered host. In vitro reconstitution experiments indicated that only BMM of curcumin-administered hosts, but not in vitro curcumin-exposed BMM, augmented BMC survival. It suggests that curcumin-dependent modulation of BMM is of indirect nature. Such prosurvival action of curcumin is associated with altered T{sub H1}/T{sub H2} cytokine balance in serum. Augmented level of serum-borne IFN-γ was found to mediate modulation of BMM to produce enhanced amount of monokines (IL-1, IL-6, TNF-α), which are suggested to augment the BMC survival. Taken together the present investigation indicates that curcumin can potentiate myelopoiesis in a tumor-bearing host, which may have implications in its therapeutic utility. Highlights: ► Curcumin augments myelopoiesis in tumor-bearing host. ► Bone marrow resident macrophages mediate curcumin-dependent augmented myelopoiesis. ► Serum borne cytokine are implicated in modulation of bone marrow resident

  12. Dynamic effects of parasitism by an endoparasitoid wasp on the development of two host species: implications for host quality and parasitoid fitness

    NARCIS (Netherlands)

    Harvey, J.A.

    2000-01-01

    1. The study reported here examined growth and developmental interactions between the gregarious larval koinobiont endoparasitoid Cotesia glomerata (Hymenoptera: Braconidae) and two of its hosts that vary considerably in growth potential: Pieris rapae and the larger P. brassicae (Lepidoptera:

  13. The effects of chemical and physical penetration enhancers on the percutaneous permeation of lidocaine through equine skin

    Science.gov (United States)

    2014-01-01

    Background The effect of physical and chemical permeation enhancers on in vitro transdermal permeation of lidocaine was investigated in the horse. Therefore, the effect of six vehicles (phosphate-buffered saline (PBS), 50% ethanol, 50% propylene glycol, 50% isopropylalcohol, 50% isopropylalcohol/isopropylmyristate and 50% dimethylsulfoxide) was examined as well as the effect of microneedle pretreatment with different needle lengths on transdermal drug delivery of lidocaine. The skin was obtained from the thorax of six Warmblood horses and was stored up to two weeks at - 20°C. Franz-type diffusion cells were used to study the transdermal permeation through split skin (600 μm thickness). The amount of lidocaine in the receptor fluid was determined by UV–VIS high-performance liquid chromatography. Results All investigated vehicle supplementations diminished the transdermal flux of lidocaine through equine skin in comparison to pure PBS except dimethylsulfoxide, which resulted in comparable permeation rates to PBS. The maximum flux (Jmax) was 1.6-1.8 fold lower for lidocaine applied in 50% ethanol, propylene glycol, isopropylalcohol and isopropylalcohol/isopropylmyristate. A significant higher Jmax of lidocaine was observed when lidocaine was applied in PBS onto microneedle pretreated skin with similar permeation rates in both needle lengths. After 6 hours, 1.7 fold higher recovery rates were observed in the microneedle pretreated skin samples than in the untreated control samples. The lagtimes were reduced to 20–50% in the microneedle pretreated skin samples. Conclusion Microneedles represent a promising tool for transdermal lidocaine application in the horse with a rapid systemic bioavailability. PMID:24950611

  14. Effects of shortened host life span on the evolution of parasite life history and virulence in a microbial host-parasite system

    Directory of Open Access Journals (Sweden)

    Koella Jacob C

    2009-03-01

    Full Text Available Abstract Background Ecological factors play an important role in the evolution of parasite exploitation strategies. A common prediction is that, as shorter host life span reduces future opportunities of transmission, parasites compensate with an evolutionary shift towards earlier transmission. They may grow more rapidly within the host, have a shorter latency time and, consequently, be more virulent. Thus, increased extrinsic (i.e., not caused by the parasite host mortality leads to the evolution of more virulent parasites. To test these predictions, we performed a serial transfer experiment, using the protozoan Paramecium caudatum and its bacterial parasite Holospora undulata. We simulated variation in host life span by killing hosts after 11 (early killing or 14 (late killing days post inoculation; after killing, parasite transmission stages were collected and used for a new infection cycle. Results After 13 cycles (≈ 300 generations, parasites from the early-killing treatment were less infectious, but had shorter latency time and higher virulence than those from the late-killing treatment. Overall, shorter latency time was associated with higher parasite loads and thus presumably with more rapid within-host replication. Conclusion The analysis of the means of the two treatments is thus consistent with theory, and suggests that evolution is constrained by trade-offs between virulence, transmission and within-host growth. In contrast, we found little evidence for such trade-offs across parasite selection lines within treatments; thus, to some extent, these traits may evolve independently. This study illustrates how environmental variation (experienced by the host can lead to the evolution of distinct parasite strategies.

  15. Size-dependent penetration of carbon dots inside the ferritin nanocages: evidence for the quantum confinement effect in carbon dots.

    Science.gov (United States)

    Bhattacharya, Arpan; Chatterjee, Surajit; Prajapati, Roopali; Mukherjee, Tushar Kanti

    2015-05-21

    The origin of the excitation wavelength (λex)-dependent photoluminescence (PL) of carbon dots (CDs) is poorly understood and still remains obscured. This phenomenon is often explained on the basis of surface trap/defect states, while the effect of quantum confinement is highly neglected in the literature. Here, we have shown that the λex-dependent PL of CDs is mainly due to the inhomogeneous size distribution. We have demonstrated the λex-dependent PL quenching of CDs inside the ferritin nanocages through selective optical excitation of differently sized CDs. It has been observed that Fe(3+) ions of ferritin effectively quench the PL of CDs due to static electron transfer, which is driven by favorable electrostatic interactions. However, control experiment with aqueous Fe(3+) ions in bulk medium revealed λex-independent PL quenching of CDs. The λex-dependent PL quenching of CDs by Fe(3+) ions of ferritin has been rationalized on the basis of a different extent of accessibility of Fe(3+) ions by differently sized CDs through the funnel-shaped ferritin channels. PL microscopy of individual CDs has been performed to get further information about their inherent PL properties at single dot resolution. Our results have shown that these hydrophilic CDs can be used as potential iron sensors in biological macromolecules.

  16. Do host-associated gut microbiota mediate the effect of an herbicide on disease risk in frogs?

    Science.gov (United States)

    Knutie, Sarah A; Gabor, Caitlin R; Kohl, Kevin D; Rohr, Jason R

    2018-03-01

    Environmental stressors, such as pollutants, can increase disease risk in wildlife. For example, the herbicide atrazine affects host defences (e.g. resistance and tolerance) of the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), but the mechanisms for these associations are not entirely clear. Given that pollutants can alter the gut microbiota of hosts, which in turn can affect their health and immune systems, one potential mechanism by which pollutants could increase infection risk is by influencing host-associated microbiota. Here, we test whether early-life exposure to the estimated environmental concentration (EEC; 200 μg/L) of atrazine affects the gut bacterial composition of Cuban tree frog (Osteopilus septentrionalis) tadpoles and adults and whether any atrazine-induced change in community composition might affect host defences against Bd. We also determine whether early-life changes in the stress hormone corticosterone affect gut microbiota by experimentally inhibiting corticosterone synthesis with metyrapone. With the exception of changing the relative abundances of two bacterial genera in adulthood, atrazine did not affect gut bacterial diversity or community composition of tadpoles (in vivo or in vitro) or adults. Metyrapone did not significantly affect bacterial diversity of tadpoles, but significantly increased bacterial diversity of adults. Gut bacterial diversity during Bd exposure did not predict host tolerance or resistance to Bd intensity in tadpoles or adults. However, early-life bacterial diversity negatively predicted Bd intensity as adult frogs. Specifically, Bd intensity as adults was associated negatively with the relative abundance of phylum Fusobacteria in the guts of tadpoles. Our results suggest that the effect of atrazine on Bd infection risk is not mediated by host-associated microbiota because atrazine does not affect microbiota of tadpoles or adults. However, host-associated microbes seem important in host resistance

  17. The effects of seasonality on host-bat fly ecological networks in a temperate mountain cave.

    Science.gov (United States)

    Rivera-García, Karina D; Sandoval-Ruiz, César A; Saldaña-Vázquez, Romeo A; Schondube, Jorge E

    2017-04-01

    Changes in the specialization of parasite-host interactions will be influenced by variations in host species composition. We evaluated this hypothesis by comparing the composition of bats and bat flies within a roost cave over one annual. Five bat and five bat fly species occupied the cave over the course of the study. Bat species composition was 40% different in the rainy season compared with the dry-cold and dry-warm seasons. Despite the incorporation of three new bat species into the cave during the rainy season, bat fly species composition was not affected by seasonality, since the bats that arrived in the rainy season only contributed one new bat fly species at a low prevalence. Bat-bat fly ecological networks were less specialized in the rainy season compared with the dry-cold and dry-warm seasons because of the increase of host overlap among bat fly species during this season. This study suggests that seasonality promote: (1) differences in host species composition, and (2) a reduction in the specialization of host-parasite ecological networks.

  18. Effects of Wing Leading Edge Penetration with Venting and Exhaust Flow from Wheel Well at Mach 24 in Flight

    Science.gov (United States)

    Gnoffo, Peter A.

    2003-01-01

    A baseline solution for CFD Point 1 (Mach 24) in the STS-107 accident investigation was modified to include effects of: (1) holes through the leading edge into a vented cavity; and (2) a scarfed, conical nozzle directed toward the centerline of the vehicle from the forward, inboard corner of the landing gear door. The simulations were generated relatively quickly and early in the investigation because simplifications were made to the leading edge cavity geometry and an existing utility to merge scarfed nozzle grid domains with structured baseline external domains was implemented. These simplifications in the breach simulations enabled: (1) a very quick grid generation procedure; and (2) high fidelity corroboration of jet physics with internal surface impingements ensuing from a breach through the leading edge, fully coupled to the external shock layer flow at flight conditions. These simulations provided early evidence that the flow through a two-inch diameter (or larger) breach enters the cavity with significant retention of external flow directionality. A normal jet directed into the cavity was not an appropriate model for these conditions at CFD Point 1 (Mach 24). The breach diameters were of the same order or larger than the local, external boundary-layer thickness. High impingement heating and pressures on the downstream lip of the breach were computed. It is likely that hole shape would evolve as a slot cut in the direction of the external streamlines. In the case of the six-inch diameter breach the boundary layer is fully ingested. The intent of externally directed jet simulations in the second scenario was to approximately model aerodynamic effects of a relatively large internal wing pressure, fueled by combusting aluminum, which deforms the corner of the landing gear door and directs a jet across the windside surface. These jet interactions, in and of themselves, were not sufficiently large to explain observed aerodynamic behavior.

  19. A negative effect of Campylobacter capsule on bacterial interaction with an analogue of a host cell receptor.

    Science.gov (United States)

    Rubinchik, Sona; Seddon, Alan M; Karlyshev, Andrey V

    2014-05-31

    Campylobacter jejuni (C. jejuni) is the leading causative agent of bacterial gastrointestinal infections. The rise of antibiotic resistant forms of this pathogen necessitates the development of novel intervention strategies. One approach is the design of drugs preventing bacterial attachment to host cells. Although some putative C. jejuni adhesins have been identified, the molecular mechanisms of their interaction with host cells and their role in pathogenesis remain to be elucidated. C. jejuni adhesion may also be modulated by a bacterial capsule. However, the role of this structure in adhesion was not clear due to conflicting results published by different research groups. The aim of this study was to clarify the role of capsule in bacterial interaction with host cells by using an in vitro model of adhesion and an analogue of a host cell receptor. In this study, we developed an in vitro bacterial adhesion assay, which was validated using various tests, including competitive inhibition studies, exoglycosydase treatment and site-directed mutagenesis. We demonstrate that PEB3 is one of the cell surface glycoproteins required for bacterial interaction with an analogue of a host cell receptor. In contrast, JlpA glycoprotein adhesin is not required for such interaction. We demonstrate that the production of capsule reduces bacterial attachment, and that the genes involved in capsule and PEB3 adhesin biosynthesis are differentially regulated. In this study we report an in vitro model for the investigation of bacterial interaction with analogs of host cell receptors. The results suggest an interfering effect of capsule on bacterial attachment. In addition, using a liquid culture, we demonstrate differential expression of a gene involved in capsule production (kpsM) and a gene encoding a glycoprotein adhesin (peb3). Further studies are required in order to establish if these genes are also differentially regulated during the infection process. The results will assist in

  20. Effect of Exopolysaccharides on Phage-Host Interactions in Lactococcus lactis

    Science.gov (United States)

    Deveau, Hélène; Van Calsteren, Marie-Rose; Moineau, Sylvain

    2002-01-01

    In this study, we report that Lactococcus lactis strains producing exopolysaccharides (EPS) are sensitive to virulent phages. Eight distinct lytic phages (Q61 to Q68) specifically infecting Eps+ strains were isolated in 47 buttermilk samples obtained from 13 North American factories. The eight phages were classified within the 936 species by the multiplex PCR method, indicating that these phages are not fundamentally distinct from those infecting Eps− L. lactis strains. The host range of these phages was determined with 19 Lactococcus strains, including 7 Eps+ and 12 Eps− cultures. Three phages (Q62, Q63, and Q64) attacked only the Eps+ strain SMQ-419, whereas the five other phages (Q61, Q65, Q66, Q67, and Q68) infected only the Eps+ strain SMQ-420. The five other Eps+ strains (H414, MLT2, MLT3, SMQ-461, and SMQ-575) as well as the 12 Eps− strains were insensitive to these phages. The monosaccharide composition of the polymer produced by the seven Eps+ strains was determined. The EPS produced by strains MLT3, SMQ-419, and SMQ-575 contained glucose, galactose, and rhamnose. The EPS fabricated by H414 contained only galactose. The EPS made by MLT2, SMQ-420, and SMQ-461 contained glucose and galactose. These findings indicate that the sugar composition of the EPS has no effect on phage sensitivity. The plasmid encoding the eps operon was cured from the two phage-sensitive strains. The cured derivatives were still phage sensitive, which indicates that EPS are not necessary for phage infection. Phage adsorption assays showed that the production of EPS does not confer a significant phage resistance phenotype. PMID:12200288

  1. Effects of host-plant population size and plant sex on a specialist leaf-miner

    DEFF Research Database (Denmark)

    Bañuelos, María-José; Kollmann, Johannes Christian

    2011-01-01

    was negatively related to leaf-miner prevalence, with larger egg and mine densities in small populations. Percentage of eggs hatching and developing into mines, and percentage of adult flies emerging from mines also differed among host populations, but were not related to population size or host cover. Feeding......Animal population density has been related to resource patch size through various hypotheses such as those derived from island biogeography and resource concentration theory. This theoretical framework can be also applied to planteherbivore interactions, and it can be modified by the sex...... of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different...

  2. The Effect of Novolac and Graphite Polycrystal on the Acetone Penetration and Thermal Resistance of Nanocomposites Based on Nitrile Rubber

    Directory of Open Access Journals (Sweden)

    Rasool Mahboudi

    2015-03-01

    Full Text Available Developments of high diffusive environments in coincidence with emerging fluids with strong ability to destroy polymeric systems have resulted in rapid deformation and destruction of polymeric parts when in contact with such aggressive environments. Therefore, nowadays, there is a great need to develop highly resistant materials towards aggressive chemicals and harsh conditions. In this paper the effect of graphite polycrystal powders and novolac type phenolic resin has been experimentally studied towards acetone diffusion and thermal stability of polyacrylonitrile butadiene rubber/novolac/graphite polycrystal nanocomposites. The results obtained from dynamic mechanical thermal analysis (DMTA and swelling in acetone showed that after 32 h samples reached to 94.2% of final swelling state. By using Avrami equation and swelling experimental data, the functionality of Ln(m/m0 to novolac and graphite polycrystal weight fraction and test duration time were evaluated. This theoretical equation evaluated and predicted the amount of Ln(m/m0 with 5.92% error after 32 h. Increases in graphite polycrystal content were followed by decreases in diffusion of acetone and modulus, before glass transition temperature, and increased thermal stability and thermal resistance of the nanocomposites. Increases in novolac content by 35 wt%, decreased glass transition temperature, thermal stability and thermal resistance of the nanocomposites. In nanocomposite, containing 45 wt% of novolac, dynamic mechanical thermal analysis (DMTA data and scanning electron microscope (SEM images showed phase separation of thermoset and elastomer in the nanocomposite blend.

  3. Effect of reproductive mode on host plant utilization of melon aphid (Hemiptera: Aphididae).

    Science.gov (United States)

    Liu, Xiangdong; Gao, Xue

    2010-12-01

    Variation in the reproductive mode of melon aphid Aphis gossypii Glover occurred on the large geographic scale, but the performance of different reproductive modes to use host plant is poorly understood. Life tables of melon aphid population that undergo the anholocyclic, androcyclic, and intermediate reproductive mode were conducted on different host plants. The results showed that the anholocyclic and androcyclic strains could become adults and produce offspring on cotton Gossypium hirsutum L., whereas the intermediate strain could not. The survival rate, net reproductive rate (R(0)), and intrinsic rate of natural increase (r(m)) of the androcyclic strain on cotton were significantly greater than that of the anholocyclic strain. The three strains could aptly use cucurbits host plants including cucumber Cucumis sativa L., pumpkin Cucurbita moschata (Duchesne ex Lam.), and zucchini Cucurbita pepo L.; survival rate and R(0) were not significantly different on these two host plants. Moreover, the r(m) of the anholocyclic strain on cucumber and the androcyclic strain on pumpkin and zucchini were significantly greater than that of the other two strains. The abilities of the three strains to use a host plant were flexible, because their r(m) on pumpkin or zucchini became equal after rearing for four successive generations; furthermore, the intermediate strain attained the ability to use cotton, and the performance of anholocyclic and intermediate strains to use cotton also significantly increased after feeding on pumpkin or zucchini for one or three generations. It was concluded that the reproductive mode and feeding experience affected the performance of melon aphid to use a host plant. © 2010 Entomological Society of America

  4. Cost-effective expression and purification of antimicrobial and host defense peptides in Escherichia coli

    DEFF Research Database (Denmark)

    Bommarius, B.; Jenssen, Håvard; Elliott, M.

    2010-01-01

    Cationic antimicrobial host defense peptides (HDPs) combat infection by directly killing a wide variety of microbes, and/or modulating host immunity. HDPs have great therapeutic potential against antibioticresistant bacteria, viruses and even parasites, but there are substantial roadblocks to the...... in large-scale under Good Laboratory Manufacturing Practice (GMP) conditions for therapeutic application in humans....... to their therapeutic application. High manufacturing costs associated with amino acid precursors have limited the delivery of inexpensive therapeutics through industrial-scale chemical synthesis. Conversely, the production of peptides in bacteria by recombinant DNA technology has been impeded by the antimicrobial...

  5. Penetration Tester's Open Source Toolkit

    CERN Document Server

    Faircloth, Jeremy

    2011-01-01

    Great commercial penetration testing tools can be very expensive and sometimes hard to use or of questionable accuracy. This book helps solve both of these problems. The open source, no-cost penetration testing tools presented do a great job and can be modified by the user for each situation. Many tools, even ones that cost thousands of dollars, do not come with any type of instruction on how and in which situations the penetration tester can best use them. Penetration Tester's Open Source Toolkit, Third Edition, expands upon existing instructions so that a professional can get the most accura

  6. Design of a dual-ligand system using a specific ligand and cell penetrating peptide, resulting in a synergistic effect on selectivity and cellular uptake.

    Science.gov (United States)

    Takara, Kazuhiro; Hatakeyama, Hiroto; Ohga, Noritaka; Hida, Kyoko; Harashima, Hideyoshi

    2010-08-30

    In this study, a dual-ligand liposomal system comprised of a specific ligand and a cell penetrating peptide (CPP) is described to enhance selectivity and cellular uptake. Dual-ligand PEGylated liposomes were prepared by modifying the end of the PEG with an NGR motif peptide, followed by a surface coating of the liposomes with stearylated oligoarginine (STR-RX). The NGR motif recognizes CD13, a marker protein located on tumor endothelial cells. A suitable number of RX units was determined to be R4, since it can be masked by the PEG aqueous layer. Although no enhanced cellular uptake was observed when a single modification of PEGylated liposomes with either NGR- or STR-R4 was used, the dual-modification with NGR and STR-R4 stimulated uptake of PEGylated liposomes by CD13 positive cells, and this uptake was superior to that obtained by PEG-unmodified liposomes modified with STR-R4. The dual-ligand system shows a synergistic effect on cellular uptake. Collectively, the dual-ligand system promises to be useful in the development efficient and specific drug delivery systems. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Bodily action penetrates affective perception.

    Science.gov (United States)

    Fantoni, Carlo; 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

  8. Bodily action penetrates affective perception

    Directory of Open Access Journals (Sweden)

    Carlo Fantoni

    2016-02-01

    Full Text Available 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

  9. Sequential Delivery of Host-Induced Virulence Effectors by Appressoria and Intracellular Hyphae of the Phytopathogen Colletotrichum higginsianum

    Science.gov (United States)

    Kleemann, Jochen; Neumann, Ulla; van Themaat, Emiel Ver Loren; van der Does, H. Charlotte; Hacquard, Stéphane; Stüber, Kurt; Will, Isa; Schmalenbach, Wolfgang; Schmelzer, Elmon; O'Connell, Richard J.

    2012-01-01

    Phytopathogens secrete effector proteins to manipulate their hosts for effective colonization. Hemibiotrophic fungi must maintain host viability during initial biotrophic growth and elicit host death for subsequent necrotrophic growth. To identify effectors mediating these opposing processes, we deeply sequenced the transcriptome of Colletotrichum higginsianum infecting Arabidopsis. Most effector genes are host-induced and expressed in consecutive waves associated with pathogenic transitions, indicating distinct effector suites are deployed at each stage. Using fluorescent protein tagging and transmission electron microscopy-immunogold labelling, we found effectors localised to stage-specific compartments at the host-pathogen interface. In particular, we show effectors are focally secreted from appressorial penetration pores before host invasion, revealing new levels of functional complexity for this fungal organ. Furthermore, we demonstrate that antagonistic effectors either induce or suppress plant cell death. Based on these results we conclude that hemibiotrophy in Colletotrichum is orchestrated through the coordinated expression of antagonistic effectors supporting either cell viability or cell death. PMID:22496661

  10. Physical Penetration Testing: A Whole New Story in Penetration Testing

    NARCIS (Netherlands)

    Dimkov, T.; Pieters, Wolter

    2011-01-01

    Physical penetration testing plays an important role in assuring a company that the security policies are properly enforced and that the security awareness of the employees is on the appropriate level. In physical penetration tests the tester physically enters restricted locations and directly

  11. The penetrating depth analysis of Lunar Penetrating Radar onboard Chang’e-3 rover

    Science.gov (United States)

    Xing, Shu-Guo; Su, Yan; Feng, Jian-Qing; Dai, Shun; Xiao, Yuan; Ding, Chun-Yu; Li, Chun-Lai

    2017-04-01

    Lunar Penetrating Radar (LPR) has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from noise. First, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method (CCM) is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m ({\\varepsilon }r=6.6) and from 13.0 m to 17.5 m ({\\varepsilon }r=2.3), respectively.

  12. Temperature Effects on Phase Relations in Ultramafic-Hosted Hydrothermal Systems

    Science.gov (United States)

    Seyfried, W. E.; Foustoukos, D. I.; Fu, Q.

    2005-12-01

    The effect of temperature on alteration processes in ultramafic hosted hydrothermal systems is significant and manifest by complex changes in secondary mineralization and the composition of coexisting fluids, as suggested by recent experimental and theoretical data. At relatively high temperatures (400C) olivine recrystallization reactions are sluggish, generally limiting mass transfer. In SiO2 bearing fluids, such as the case for the Rainbow hydrothermal system (36N, MAR), evidence indicates olivine recrystallization to a more fayalite-rich phase and talc, enhancing olivine stability at reaction zone conditions. These phases plus tremolite play a key role in maintaining fluid acidity, accounting for the unusually high levels of dissolved metals that characterize the high temperature Rainbow vent fluids. In contrast, hydrothermal alteration of ultramafic rocks by seawater at temperatures below 300C generally results in high pH fluids, serpentinization of olivine and coexisting pyroxene, and Ca for Mg exchange in the fluid. Data also indicate potentially high dissolved H2 and low dissolved Fe and total dissolved sulfide species. Analogous processes likely characterize subseafloor reaction zones at the Lost City Hydrothermal Field (LCHF), which lies on the Atlantis Massif at 30N, 15 km west of the Mid-Atlantic Ridge. Indeed, geochemical modeling of the Lost City vent fluid chemistry suggests subseafloor temperatures of approximately 200C, which are considerably greater than the measured vent fluid temperatures (40 to 90C), suggesting conductive cooling and seawater mixing effects; processes consistent with the reported mineralization of chimney structures. Available data also suggest moderately high fluid/rock mass ratios, which in combination with reaction zone temperature estimates make it unlikely that hydrothermal circulation can be a direct result of the exothermic nature of the conversion of olivine to serpentine. Accordingly, alternative heat sources need to

  13. Effect of host insect sterols on the development and sterol composition of Steinernema feltiae.

    Science.gov (United States)

    Morrison, A H; Ritter, K S

    1986-05-01

    Steinernema feltiae (= Neoaplectana carpocapsae), 'All' strain, was propagated in larvae of the corn earworm, Heliothis zea, which contained various sterols, in order to determine how the sterol composition of the host affects the growth, development and sterol composition of this insect-parasitic nematode. S. feltiae completed its life cycle normally in insects containing primarily cholesterol, cholestanol or 7-dehydrocholesterol, although the sterol composition of the dauer stage was affected by the sterol composition of the host. When the nematode was reared in insects containing primarily cholesterol, 55% of the sterol in the dauers was cholesterol and the other 46% was lathosterol. In contrast, cholestanol (70%) and lathostetrol (31%) were the sterols present in nematodes reared in H. zea containing primarily cholestanol. Cholestanol (43%), lathosterol (34%), campestanol and/or another 24-methylsterol (23%) and cholesterol (1%) were the sterols present in nematodes reared in H. zea containing campestanol and cholestanol as its major sterols. Lathosterol was the major sterol present in nematodes reared in H. zea containing principally 7-dehydrochlesterol. Therefore, in each case, S. feltiae metabolized some host sterol to lathosterol but the relative percentage of lathosterol in the nematode increased as it was exposed to delta 0-, delta 5- and delta 5,7-sterols, respectively. The ability of S. feltiae to utilize different host sterols may, in part, explain its success in parasitizing a wide variety of insects.

  14. Effect of fire on a seed bank pathogen and on seeds of its host Bromus tectorum

    Science.gov (United States)

    J. Beckstead; S.E. Meyer; L.E. Street; P.S. Allen

    2010-01-01

    The generalist pathogen Pyrenophora semeniperda (Brittlebank and Adam) Shoemaker occurs primarily in cheatgrass (Bromus tectorum L.) seed banks, where it causes high seed mortality (Beckstead et al. 2007; Meyer et al. 2007). How does fire impact survival of a fungal seed pathogen, P. semeniperda, versus survival of the seeds of its cheatgrass host, the invasive Bromus...

  15. Plant-feeding nematodes in coastal sand dunes: occurrence, host specificity and effects on plant growth

    NARCIS (Netherlands)

    Brinkman, E.P.; Duyts, H.; Karssen, G.; Stoel, C.D.; Putten, van der W.H.

    2015-01-01

    Aims Coastal sand dunes have a well-established abiotic gradient from beach to land and a corresponding spatial gradient of plant species representing succession in time. Here, we relate the distribution of plant-feeding nematodes with dominant plant species in the field to host specialization and

  16. Great spotted cuckoo nestlings have no antipredatory effect on magpie or carrion crow host nests in southern Spain.

    Directory of Open Access Journals (Sweden)

    Manuel Soler

    Full Text Available Host defences against cuckoo parasitism and cuckoo trickeries to overcome them are a classic example of antagonistic coevolution. Recently it has been reported that this relationship may turn to be mutualistic in the case of the carrion crow (Corvus corone and its brood parasite, the great spotted cuckoo (Clamator glandarius, given that experimentally and naturally parasitized nests were depredated at a lower rate than non-parasitized nests. This result was interpreted as a consequence of the antipredatory properties of a fetid cloacal secretion produced by cuckoo nestlings, which presumably deters predators from parasitized host nests. This potential defensive mechanism would therefore explain the detected higher fledgling success of parasitized nests during breeding seasons with high predation risk. Here, in a different study population, we explored the expected benefits in terms of reduced nest predation in naturally and experimentally parasitized nests of two different host species, carrion crows and magpies (Pica pica. During the incubation phase non-parasitized nests were depredated more frequently than parasitized nests. However, during the nestling phase, parasitized nests were not depredated at a lower rate than non-parasitized nests, neither in magpie nor in carrion crow nests, and experimental translocation of great spotted cuckoo hatchlings did not reveal causal effects between parasitism state and predation rate of host nests. Therefore, our results do not fit expectations and, thus, do not support the fascinating possibility that great spotted cuckoo nestlings could have an antipredatory effect for host nestlings, at least in our study area. We also discuss different possibilities that may conciliate these with previous results, but also several alternative explanations, including the lack of generalizability of the previously documented mutualistic association.

  17. Great spotted cuckoo nestlings have no antipredatory effect on magpie or carrion crow host nests in southern Spain.

    Science.gov (United States)

    Soler, Manuel; de Neve, Liesbeth; Roldán, María; Pérez-Contreras, Tomás; Soler, Juan José

    2017-01-01

    Host defences against cuckoo parasitism and cuckoo trickeries to overcome them are a classic example of antagonistic coevolution. Recently it has been reported that this relationship may turn to be mutualistic in the case of the carrion crow (Corvus corone) and its brood parasite, the great spotted cuckoo (Clamator glandarius), given that experimentally and naturally parasitized nests were depredated at a lower rate than non-parasitized nests. This result was interpreted as a consequence of the antipredatory properties of a fetid cloacal secretion produced by cuckoo nestlings, which presumably deters predators from parasitized host nests. This potential defensive mechanism would therefore explain the detected higher fledgling success of parasitized nests during breeding seasons with high predation risk. Here, in a different study population, we explored the expected benefits in terms of reduced nest predation in naturally and experimentally parasitized nests of two different host species, carrion crows and magpies (Pica pica). During the incubation phase non-parasitized nests were depredated more frequently than parasitized nests. However, during the nestling phase, parasitized nests were not depredated at a lower rate than non-parasitized nests, neither in magpie nor in carrion crow nests, and experimental translocation of great spotted cuckoo hatchlings did not reveal causal effects between parasitism state and predation rate of host nests. Therefore, our results do not fit expectations and, thus, do not support the fascinating possibility that great spotted cuckoo nestlings could have an antipredatory effect for host nestlings, at least in our study area. We also discuss different possibilities that may conciliate these with previous results, but also several alternative explanations, including the lack of generalizability of the previously documented mutualistic association.

  18. Implementation of the effects of physicochemical properties on the foliar penetration of pesticides and its potential for estimating pesticide volatilization from plants.

    Science.gov (United States)

    Lichiheb, Nebila; Personne, Erwan; Bedos, Carole; Van den Berg, Frederik; Barriuso, Enrique

    2016-04-15

    Volatilization from plant foliage is known to have a great contribution to pesticide emission to the atmosphere. However, its estimation is still difficult because of our poor understanding of processes occurring at the leaf surface. A compartmental approach for dissipation processes of pesticides applied on the leaf surface was developed on the base of experimental study performed under controlled conditions using laboratory volatilization chamber. This approach was combined with physicochemical properties of pesticides and was implemented in SURFATM-Pesticides model in order to predict pesticide volatilization from plants in a more mechanistic way. The new version of SURFATM-Pesticide model takes into account the effect of formulation on volatilization and leaf penetration. The model was evaluated in terms of 3 pesticides applied on plants at the field scale (chlorothalonil, fenpropidin and parathion) which display a wide range of volatilization rates. The comparison of modeled volatilization fluxes with measured ones shows an overall good agreement for the three tested compounds. Furthermore the model confirms the considerable effect of the formulation on the rate of the decline in volatilization fluxes especially for systemic products. However, due to the lack of published information on the substances in the formulations, factors accounting for the effect of formulation are described empirically. A sensitivity analysis shows that in addition to vapor pressure, the octanol-water partition coefficient represents important physicochemical properties of pesticides affecting pesticide volatilization from plants. Finally the new version of SURFATM-Pesticides is a prospecting tool for key processes involved in the description of pesticide volatilization from plants. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Effects of juvenile host density and food availability on adult immune response, parasite resistance and virulence in a Daphnia-parasite system.

    Directory of Open Access Journals (Sweden)

    Corine N Schoebel

    Full Text Available Host density can increase infection rates and reduce host fitness as increasing population density enhances the risk of becoming infected either through increased encounter rate or because host condition may decline. Conceivably, potential hosts could take high host density as a cue to up-regulate their defence systems. However, as host density usually covaries with food availability, it is difficult to examine the importance of host density in isolation. Thus, we performed two full-factorial experiments that varied juvenile densities of Daphnia magna (a freshwater crustacean and food availability independently. We also included a simulated high-density treatment, where juvenile experimental animals were kept in filtered media that previously maintained Daphnia at high-density. Upon reaching adulthood, we exposed the Daphnia to their sterilizing bacterial parasite, Pasteuria ramosa, and examined how the juvenile treatments influenced the likelihood and severity of infection (Experiment I and host immune investment (Experiment II. Neither juvenile density nor food treatments affected the likelihood of infection; however, well-fed hosts that were well-fed as juveniles produced more offspring prior to sterilization than their less well-fed counterparts. By contrast, parasite growth was independent of host juvenile resources or host density. Parasite-exposed hosts had a greater number of circulating haemocytes than controls (i.e., there was a cellular immune response, but the magnitude of immune response was not mediated by food availability or host density. These results suggest that density dependent effects on disease arise primarily through correlated changes in food availability: low food could limit parasitism and potentially curtail epidemics by reducing both the host's and parasite's reproduction as both depend on the same food.

  20. Modified suturing contact lens for penetrating keratoplasty.

    Science.gov (United States)

    Kramer, S G; Stewart, H L

    1978-11-01

    The authors have previously described a suturing contact lens that protects the corneal endothelium by aiding in the maintenance of the anterior chamber during penetrating keratoplasty. This report describes structural modifications of the suturing contact lens, which improve its stability and effectiveness. An additional configuration for use in corneal lacerations is presented.

  1. Tree root mapping with ground penetrating radar

    CSIR Research Space (South Africa)

    Van Schoor, Abraham M

    2009-09-01

    Full Text Available In this paper, the application of ground penetrating radar (GPR) for the mapping of near surface tree roots is demonstrated. GPR enables tree roots to be mapped in a non-destructive and cost-effective manner and is therefore a useful prospecting...

  2. Host species and environmental effects on bacterial communities associated with Drosophila in the laboratory and in the natural environment.

    Directory of Open Access Journals (Sweden)

    Fabian Staubach

    Full Text Available The fruit fly Drosophila is a classic model organism to study adaptation as well as the relationship between genetic variation and phenotypes. Although associated bacterial communities might be important for many aspects of Drosophila biology, knowledge about their diversity, composition, and factors shaping them is limited. We used 454-based sequencing of a variable region of the bacterial 16S ribosomal RNA gene to characterize the bacterial communities associated with wild and laboratory Drosophila isolates. In order to specifically investigate effects of food source and host species on bacterial communities, we analyzed samples from wild Drosophila melanogaster and D. simulans collected from a variety of natural substrates, as well as from adults and larvae of nine laboratory-reared Drosophila species. We find no evidence for host species effects in lab-reared flies; instead, lab of origin and stochastic effects, which could influence studies of Drosophila phenotypes, are pronounced. In contrast, the natural Drosophila-associated microbiota appears to be predominantly shaped by food substrate with an additional but smaller effect of host species identity. We identify a core member of this natural microbiota that belongs to the genus Gluconobacter and is common to all wild-caught flies in this study, but absent from the laboratory. This makes it a strong candidate for being part of what could be a natural D. melanogaster and D. simulans core microbiome. Furthermore, we were able to identify candidate pathogens in natural fly isolates.

  3. Host Species and Environmental Effects on Bacterial Communities Associated with Drosophila in the Laboratory and in the Natural Environment

    Science.gov (United States)

    Staubach, Fabian; Baines, John F.; Künzel, Sven; Bik, Elisabeth M.; Petrov, Dmitri A.

    2013-01-01

    The fruit fly Drosophila is a classic model organism to study adaptation as well as the relationship between genetic variation and phenotypes. Although associated bacterial communities might be important for many aspects of Drosophila biology, knowledge about their diversity, composition, and factors shaping them is limited. We used 454-based sequencing of a variable region of the bacterial 16S ribosomal RNA gene to characterize the bacterial communities associated with wild and laboratory Drosophila isolates. In order to specifically investigate effects of food source and host species on bacterial communities, we analyzed samples from wild Drosophila melanogaster and D. simulans collected from a variety of natural substrates, as well as from adults and larvae of nine laboratory-reared Drosophila species. We find no evidence for host species effects in lab-reared flies; instead, lab of origin and stochastic effects, which could influence studies of Drosophila phenotypes, are pronounced. In contrast, the natural Drosophila–associated microbiota appears to be predominantly shaped by food substrate with an additional but smaller effect of host species identity. We identify a core member of this natural microbiota that belongs to the genus Gluconobacter and is common to all wild-caught flies in this study, but absent from the laboratory. This makes it a strong candidate for being part of what could be a natural D. melanogaster and D. simulans core microbiome. Furthermore, we were able to identify candidate pathogens in natural fly isolates. PMID:23967097

  4. Particle penetration and radiation effects

    CERN Document Server

    Sigmund, Peter

    This book, which has evolved from the author’s lectures at the University of Copenhagen and the University of Southern Denmark, draws on his experience as an active researcher in the interaction of charged particles with matter over more than forty years. The emphasis is on the theoretical description of fundamental phenomena, and much attention has been given to classic topics such as: Rutherford scattering; the theory of particle stopping as developed by Bohr, Bethe, Bloch and Lindhard; the statistical description of energy loss as developed by Bohr, Bothe, Williams and Landau; and numerous more recent developments. An attempt has been made to provide at least one complete derivation of a theoretical description for all central aspects. The presentation is intended to respect the ideas of the original authors, but much effort has been invested in establishing a unified and appealing notation consistent with present-day standards. It is intended that this volume will satisfy a long-standing need for a text...

  5. The brain-penetrating CXCR4 antagonist, PRX177561, increases the antitumor effects of bevacizumab and sunitinib in preclinical models of human glioblastoma

    Directory of Open Access Journals (Sweden)

    Giovanni Luca Gravina

    2017-01-01

    Full Text Available Abstract Background Glioblastoma recurrence after treatment with the anti-vascular endothelial growth factor (VEGF antibody bevacizumab is characterized by a highly infiltrative and malignant behavior that renders surgical excision and chemotherapy ineffective. It has been demonstrated that anti-VEGF/VEGFR therapies control the invasive phenotype and that relapse occurs through the increased activity of CXCR4. We therefore hypothesized that combining bevacizumab or sunitinib with the novel CXCR4 antagonist, PRX177561, would have superior antitumor activity. Methods The effects of bevacizumab, sunitinib, and PRX177561 were tested alone or in combination in subcutaneous xenografts of U87MG, U251, and T98G cells as well as on intracranial xenografts of luciferase tagged U87MG cells injected in CD1-nu/nu mice. Animals were randomized to receive vehicle, bevacizumab (4 mg/kg iv every 4 days, sunitinib (40 mg/kg po qd, or PRX177561 (50 mg/kg po qd. Results The in vivo experiments demonstrated that bevacizumab and sunitinib increase the in vivo expression of CXCR4, SDF-1α, and TGFβ1. In addition, we demonstrate that the co-administration of the novel brain-penetrating CXCR4 antagonist, PRX177561, with bevacizumab or sunitinib inhibited tumor growth and reduced the inflammation. The combination of PRX177561 with bevacizumab resulted in a synergistic reduction of tumor growth with an increase of disease-free survival (DSF and overall survival (OS, whereas the combination of PRX177561 with sunitinib showed a mild additive effect. Conclusions The CXC4 antagonist PRX177561 may be a valid therapeutic complement to anti-angiogenic therapy, particularly when used in combination with VEGF/VEGFR inhibitors. Therefore, this compound deserves to be considered for future clinical evaluation.

  6. Is Black Hole Growth a Universal Process? Exploring Selection Effects in Measurements of AGN Accretion Rates and Host Galaxies.

    Science.gov (United States)

    Jones, Mackenzie

    2018-01-01

    At the center of essentially every massive galaxy is a monstrous black hole producing luminous radiation driven by the accretion of gas. By observing these active galactic nuclei (AGN) we may trace the growth of black holes across cosmic time. However, our knowledge of the full underlying AGN population is hindered by complex observational biases. My research aims to untangle these biases by using a novel approach to simulate the impact of selection effects on multiwavelength observations.The most statistically powerful studies of AGN to date come from optical spectroscopic surveys, with some reporting a complex relationship between AGN accretion rates and host galaxy characteristics. However, the optical waveband can be strongly influenced by selection effects and dilution from host galaxy star formation. I have shown that accounting for selection effects, the Eddington ratio distribution for optically-selected AGN is consistent with a broad power-law, as seen in the X-rays (Jones et al. 2016). This suggests that a universal Eddington ratio distribution may be enough to describe the full multiwavelength AGN population.Building on these results, I have expanded a semi-numerical galaxy formation simulation to include this straightforward prescription for AGN accretion and explicitly model selection effects. I have found that a simple model for AGN accretion can broadly reproduce the host galaxies and halos of X-ray AGN, and that different AGN selection techniques yield samples with very different host galaxy properties (Jones et al. 2017). Finally, I will discuss the capabilities of this simulation to build synthetic multiwavelength SEDs in order to explore what AGN populations would be detected with the next generation of observatories. This research is supported by a NASA Jenkins Graduate Fellowship under grant no. NNX15AU32H.

  7. Effects of Host Plant on Development and Body Size of Three Haplotypes of Bactericera cockerelli (Hemiptera: Triozidae).

    Science.gov (United States)

    Mustafa, T; Horton, D R; Swisher, K D; Zack, R S; Munyaneza, J E

    2015-06-01

    Potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), is an economic pest of solanaceous crops in North and Central America, and in New Zealand. Four genetic haplotypes of the psyllid have been identified in North America. Three of these haplotypes (Central, Western, and Northwestern) are common on potato crops within the major potato-growing regions of Idaho, Oregon, and Washington. Within this growing region, a weedy perennial nightshade, Solanum dulcamara (bittersweet nightshade), has been identified to be an important overwintering host and spring or summer source of psyllids colonizing potato fields. It is unclear whether bittersweet nightshade is a highly suitable host plant for all three haplotypes known to occur in the Pacific Northwest. The objective of the present study was to examine developmental traits and adult body size of all three haplotypes of psyllids reared on potato and bittersweet nightshade. Averaged over haplotype, development times were longer for psyllids reared on nightshade than potato. Duration of the preoviposition period, egg incubation requirements, nymphal development time, and total developmental time averaged 7.4, 5.9, 23.5, and 29.5 d on nightshade and 4.9, 5.5, 22.3, and 27.9 d on potato, respectively. The largest host effects were found for the Central haplotype, which exhibited a substantially extended (by over 5 d) preoviposition period on nightshade compared with potato. Averaged over host plant, nymphal and total development times of the Northwestern haplotype were longer (25.5 and 31.1 d, respectively) than those of the Western and Central haplotypes. The Northwestern haplotype was largest in overall body size, while the Central haplotype had the smallest overall body size, irrespective of host plant. Both sexes exhibited this trend. Published by Oxford University Press on behalf of Entomological Society of America 2015.This work is written by US Government employees and is in the public domain in

  8. Top Sounder Ice Penetration

    Science.gov (United States)

    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.

  9. Effect of Whole-abdominal Irradiation on Penetration Depth of Doxorubicin in Normal Tissue After Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) in a Post-mortem Swine Model.

    Science.gov (United States)

    Khosrawipour, Veria; Khosrawipour, Tanja; Hedayat-Pour, Yousef; Diaz-Carballo, David; Bellendorf, Alexander; Böse-Ribeiro, Hugo; Mücke, Ralph; Mohanaraja, Nirushika; Adamietz, Irenäus Anton; Fakhrian, Khashayar

    2017-04-01

    This study was performed to evaluate the impact of whole-abdominal irradiation on local penetration of doxorubicin into the peritoneum and the abdominal organs in a post-mortem swine model. Doxorubicin was aerosolized into the abdominal cavity of swine at a pressure of 12 mmHg CO2 at room temperature (25°). One swine was subjected to pressurized intraperitoneal aerosol chemotherapy (PIPAC) using Micropump(©) without irradiation; the second one received 2 Gy and the third one 7 Gy whole-abdominal irradiation, 15 min prior to PIPAC application. Samples of the peritoneal surface were extracted at different positions from within the abdominal cavity. In-tissue doxorubicin penetration was measured using fluorescence microscopy on frozen thin sections. The depth of penetration of doxorubicin was found to be wide-ranging, between 17 μm on the surface of the stomach and 348 μm in the small intestine. The penetration depth into the small intestine was 348 μm, 312 μm and 265 μm for PIPAC alone, PIPAC with 2 Gy irradiation and PIPAC with 7 Gy irradiation, respectively (ppenetration into the liver was 64 μm, 55 μm and 40 μm, respectively (p=0.05). Irradiation was not found to increase the depth of doxorubicin penetration into normal tissue in the post-mortem swine model. A reduction of doxorubicin penetration was observed after application of higher irradiation doses. Further studies are warranted to determine if irradiation can be used safely as chemopotentiating agent for patients with peritoneal metastases treated with PIPAC. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  10. An Earth Penetrating Modeling Assessment

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Modelling within Host Parasite Dynamics of Schistosomiasis

    Directory of Open Access Journals (Sweden)

    Edward T. Chiyaka

    2010-01-01

    Full Text Available Schistosomiasis infection is characterized by the presence of adult worms in the portal and mesenteric veins of humans as part of a complex migratory cycle initiated by cutaneous penetration of the cercariae shed by infected freshwater snails. The drug praziquantel is not always effective in the treatment against schistosomiasis at larvae stage. However, our simulations show that it is effective against mature worms and eggs. As a result, the study and understanding of immunological responses is key in understanding parasite dynamics. We therefore introduce quantitative interpretations of human immunological responses of the disease to formulate mathematical models for the within-host dynamics of schistosomiasis. We also use numerical simulations to demonstrate that it is the level of T cells that differentiates between either an effective immune response or some degree of infection. These cells are responsible for the differentiation and recruitment of eosinophils that are instrumental in clearing the parasite. From the model analysis, we conclude that control of infection is much attributed to the value of a function f, a measure of the average number of larvae penetrating a susceptible individual having hatched from an egg released by an infected individual. This agrees with evidence that there is a close association between the ecology, the distribution of infection and the disease.

  12. Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut.

    Science.gov (United States)

    De Waele, D; Jordaan, E M; Basson, S

    1990-07-01

    The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed species; population densities increased in peanut hulls and caused severe damage to seeds of peanut grown after weeds. Roots of purple nutsedge left in the soil suppressed populations of D. destructor and root and pod development in peanut grown after the weed. However, nematode populations in peanut hulls and seeds were not suppressed. Some weed species, especially purple nutsedge which is common in peanut fields, can be used to indicate the presence of D. destructor in the absence of peanut.

  13. Modelling the effect of an alternative host population on the spread of citrus Huanglongbing

    Science.gov (United States)

    d'A. Vilamiu, Raphael G.; Ternes, Sonia; Laranjeira, Francisco F.; de C. Santos, Tâmara T.

    2013-10-01

    The objective of this work was to model the spread of citrus Huanglongbing (HLB) considering the presence of a population of alternative hosts (Murraya paniculata). We developed a compartmental deterministic mathematical model for representing the dynamics of HLB disease in a citrus orchard, including delays in the latency and incubation phases of the disease in the plants and a delay period on the nymphal stage of Diaphorina citri, the insect vector of HLB in Brazil. The results of numerical simulations indicate that alternative hosts should not play a crucial role on HLB dynamics considering a typical scenario for the Recôncavo Baiano region in Brazil . Also, the current policy of removing symptomatic plants every three months should not be expected to significantly hinder HLB spread.

  14. Effect of ambient temperature on competence of deer ticks as hosts for Lyme disease spirochetes.

    OpenAIRE

    Shih, C M; Telford, S R; Spielman, A

    1995-01-01

    We determined whether the temperature of extrinsic incubation affects the competence of vector ticks as hosts for Lyme disease spirochetes (Borrelia burgdorferi). Larval Ixodes dammini ticks that had engorged on spirochete-infected C3H mice were incubated continuously at various temperatures, and the gut contents of the resulting nymphs were examined for spirochetes by direct immunofluorescence microscopy. Spirochetes were present in virtually all nymphs kept at 27 degrees C or less for 6 mon...

  15. Effect of landscape features on the relationship between Ixodes ricinus ticks and their small mammal hosts

    OpenAIRE

    Bastian, Suzanne; Agoulon, Albert; Bouju, Agnès; Durand, Axelle; Faille, Frédéric; Lebert, Isabelle; Rantier, Yann; Plantard, Olivier; Butet, Alain

    2016-01-01

    Background The consequences of land use changes are among the most cited causes of emerging infectious diseases because they can modify the ecology and transmission of pathogens. This is particularly true for vector-borne diseases which depend on abiotic (e.g. climate) and biotic conditions (i.e. hosts and vectors). In this study, we investigated how landscape features affect the abundances of small mammals and Ixodes ricinus ticks, and how they influence their relationship. Methods From 2012...

  16. The effect of nanocrystalline silicon host on magnetic properties of encapsulated iron oxide nanoparticles.

    Science.gov (United States)

    Granitzer, P; Rumpf, K; Gonzalez-Rodriguez, R; Coffer, J L; Reissner, M

    2015-12-21

    The purpose of this work is a detailed comparison of the fundamental magnetic properties of nanocomposite systems consisting of Fe3O4 nanoparticle-loaded porous silicon as well as silicon nanotubes. Such composite structures are of potential merit in the area of magnetically guided drug delivery. For magnetic systems to be utilized in biomedical applications, there are certain magnetic properties that must be fulfilled. Therefore magnetic properties of embedded Fe3O4-nanoparticles in these nanostructured silicon host matrices, porous silicon and silicon nanotubes, are investigated. Temperature-dependent magnetic investigations have been carried out for four types of iron oxide particle sizes (4, 5, 8 and 10 nm). The silicon host, in interplay with the iron oxide nanoparticle size, plays a sensitive role. It is shown that Fe3O4 loaded porous silicon and SiNTs differ significantly in their magnetic behavior, especially the transition between superparamagnetic behavior and blocked state, due to host morphology-dependent magnetic interactions. Importantly, it is found that all investigated samples meet the magnetic precondition of possible biomedical applications of exhibiting a negligible magnetic remanence at room temperature.

  17. Large-Scale Land Acquisition and Its Effects on the Water Balance in Investor and Host Countries

    Science.gov (United States)

    Breu, Thomas; Bader, Christoph; Messerli, Peter; Heinimann, Andreas; Rist, Stephan; Eckert, Sandra

    2016-01-01

    This study examines the validity of the assumption that international large-scale land acquisition (LSLA) is motivated by the desire to secure control over water resources, which is commonly referred to as ‘water grabbing’. This assumption was repeatedly expressed in recent years, ascribing the said motivation to the Gulf States in particular. However, it must be considered of hypothetical nature, as the few global studies conducted so far focused primarily on the effects of LSLA on host countries or on trade in virtual water. In this study, we analyse the effects of 475 intended or concluded land deals recorded in the Land Matrix database on the water balance in both host and investor countries. We also examine how these effects relate to water stress and how they contribute to global trade in virtual water. The analysis shows that implementation of the LSLAs in our sample would result in global water savings based on virtual water trade. At the level of individual LSLA host countries, however, water use intensity would increase, particularly in 15 sub-Saharan states. From an investor country perspective, the analysis reveals that countries often suspected of using LSLA to relieve pressure on their domestic water resources—such as China, India, and all Gulf States except Saudi Arabia—invest in agricultural activities abroad that are less water-intensive compared to their average domestic crop production. Conversely, large investor countries such as the United States, Saudi Arabia, Singapore, and Japan are disproportionately externalizing crop water consumption through their international land investments. Statistical analyses also show that host countries with abundant water resources are not per se favoured targets of LSLA. Indeed, further analysis reveals that land investments originating in water-stressed countries have only a weak tendency to target areas with a smaller water risk. PMID:26943794

  18. Large-Scale Land Acquisition and Its Effects on the Water Balance in Investor and Host Countries.

    Directory of Open Access Journals (Sweden)

    Thomas Breu

    Full Text Available This study examines the validity of the assumption that international large-scale land acquisition (LSLA is motivated by the desire to secure control over water resources, which is commonly referred to as 'water grabbing'. This assumption was repeatedly expressed in recent years, ascribing the said motivation to the Gulf States in particular. However, it must be considered of hypothetical nature, as the few global studies conducted so far focused primarily on the effects of LSLA on host countries or on trade in virtual water. In this study, we analyse the effects of 475 intended or concluded land deals recorded in the Land Matrix database on the water balance in both host and investor countries. We also examine how these effects relate to water stress and how they contribute to global trade in virtual water. The analysis shows that implementation of the LSLAs in our sample would result in global water savings based on virtual water trade. At the level of individual LSLA host countries, however, water use intensity would increase, particularly in 15 sub-Saharan states. From an investor country perspective, the analysis reveals that countries often suspected of using LSLA to relieve pressure on their domestic water resources--such as China, India, and all Gulf States except Saudi Arabia--invest in agricultural activities abroad that are less water-intensive compared to their average domestic crop production. Conversely, large investor countries such as the United States, Saudi Arabia, Singapore, and Japan are disproportionately externalizing crop water consumption through their international land investments. Statistical analyses also show that host countries with abundant water resources are not per se favoured targets of LSLA. Indeed, further analysis reveals that land investments originating in water-stressed countries have only a weak tendency to target areas with a smaller water risk.

  19. Can host density attenuate parasitism?

    National Research Council Canada - National Science Library

    Magalhães, L; Freitas, R; Dairain, A; De Montaudouin, X

    .... Considering that these parasites infect cockles through filtration activity, our first hypothesis was that high host density will have a dilution effect so that infection intensity decreases with host density...

  20. Effects of electron irradiation on resistivity and London penetration depth of Ba1-xKxFe2As2 (x <= 0.34) iron-pnictide superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Cho, K [Ames Laboratory; Konczykowski, M [Laboratoire des Solides Irradies; Murphy, Jason [Ames Laboratory; Kim, H [Ames Laboratory; Tanatar, Makariy A [Ames Laboratory; Straszheim, Warren E [Ames Laboratory; Shen, B [Nanjing University; Wen, H H [Nanjing University; Prozorov, Ruslan [Ames Laboratory

    2014-09-01

    Irradiation with 2.5 MeV electrons at doses up to 5.2×1019 electrons/cm2 was used to introduce pointlike defects in single crystals of Ba1-xKxFe2As2 with x=0.19 (Tc=14K),0.26 (Tc=32K), 0.32 (Tc=37K), and 0.34 (Tc=39K) to study the superconducting gap structure by probing the effect of nonmagnetic scattering on electrical resistivity ρ(T) and London penetration depth λ(T). For all compositions, the irradiation suppressed the superconducting transition temperature Tc and increased resistivity. The low-temperature behavior of λ(T) is best described by the power-law function, Δλ(T)=A(T/Tc)n. While substantial suppression of Tc supports s± pairing, in samples close to the optimal doping, x=0.26, 0.32, and 0.34, the exponent n remained high (n≥3), indicating almost exponential attenuation and thus a robust full superconducting gap. For the x=0.19 composition, which exhibits coexistence of superconductivity and long-range magnetism, the suppression of Tc was much more rapid, and the exponent n decreased toward the s± dirty limit of n=2. In this sample, the irradiation also suppressed the temperature of structural/magnetic transition Tsm from 103 to 98 K, consistent with the itinerant nature of the long-range magnetic order. Our results suggest that underdoped compositions, especially in the coexisting regime, are most susceptible to nonmagnetic scattering and imply that in multiband Ba1-xKxFe2As2 superconductors, the ratio of the interband to intraband pairing strength, as well as the related gap anisotropy, increases upon the departure from the optimal doping.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Structure and development of 'witches' broom' galls in reproductive organs of Byrsonima sericea (Malpighiaceae) and their effects on host plants.

    Science.gov (United States)

    Guimarães, A L A; Neufeld, P M; Santiago-Fernandes, L D R; Vieira, A C M

    2015-03-01

    Galls are anomalies in plant development of parasitic origin that affect the cellular differentiation or growth and represent a remarkable plant-parasite interaction. Byrsonima sericea DC. (Malpighiaceae) is a super host of several different types of gall in both vegetative and reproductive organs. The existence of galls in reproductive organs and their effects on the host plant are seldom described in the literature. In this paper, we present a novel study of galls in plants of the Neotropical region: the 'witches' broom' galls developed in floral structures of B. sericea. The unaffected inflorescences are characterised by a single indeterminate main axis with spirally arranged flower buds. The flower buds developed five unaffected brownish hairy sepals and five pairs of elliptical yellow elaiophores, five yellow fringed petals, 10 stamens and a pistil with superior tricarpellar and trilocular ovary. The affected inflorescences showed changes in architecture, with branches arising from the main axis and flower buds. The flower buds exhibited several morphological and anatomical changes. The sepals, petals and carpels converted into leaf-like structures after differentiation. Stamens exhibited degeneration of the sporogenous tissue and structures containing hyphae and spores. The gynoecium did not develop, forming a central meristematic region, from which emerges the new inflorescence. In this work, we discuss the several changes in development of reproductive structures caused by witches' broom galls and their effects on reproductive success of the host plants. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  3. The effect of water contamination and host-related factors on ectoparasite load in an insectivorous bat.

    Science.gov (United States)

    Korine, Carmi; Pilosof, Shai; Gross, Amit; Morales-Malacara, Juan B; Krasnov, Boris R

    2017-07-22

    We examined the effects of sex, age, and reproductive state of the insectivorous bat Pipistrellus kuhlii on the abundance and prevalence of arthropod ectoparasites (Macronyssidae and Cimicidae) in habitats with either sewage-polluted or natural bodies of water, in the Negev Desert, Israel. We chose water pollution as an environmental factor because of the importance of water availability in desert environments, particularly for P. kuhlii, which needs to drink on a daily basis. We predicted that parasite infestation rates would be affected by both environment and demographic cohort of the host. We found that female bats in the polluted site harbored significantly more mites than female bats in the natural site and that juveniles in the polluted site harbored significantly more cimicid individuals than juveniles in the natural site. We further found that age and sex (host-related factors) affected ectoparasite prevalence and intensity (i.e., the abundance of parasites) in the polluted site. Our results may suggest that the interaction between host-related and environment-related factors affected parasite infestations, with females and young bats being more susceptible to ectoparasites when foraging over polluted water. This effect may be particularly important for bats that must drink or forage above water for other wildlife that depend on drinking water for survival.

  4. Assessing the potential effects of fungicides on nontarget gut fungi (trichomycetes) and their associated larval black fly hosts

    Science.gov (United States)

    Wilson, Emma R.; Smalling, Kelly L.; Reilly, Timothy J.; Gray, Elmer; Bond, Laura; Steele, Lance; Kandel, Prasanna; Chamberlin, Alison; Gause, Justin; Reynolds, Nicole; Robertson, Ian; Novak, Stephen; Feris, Kevin; White, Merlin M.

    2014-01-01

    Fungicides are moderately hydrophobic and have been detected in water and sediment, particularly in agricultural watersheds, but typically are not included in routine water quality monitoring efforts. This is despite their widespread use and frequent application to combat fungal pathogens. Although the efficacy of these compounds on fungal pathogens is well documented, little is known about their effects on nontarget fungi. This pilot study, a field survey in southwestern Idaho from April to December 2010 on four streams with varying pesticide inputs (two agricultural and two reference sites), was conducted to assess nontarget impact of fungicides on gut fungi, or trichomycetes. Tissues of larval black flies (Diptera: Simuliidae), hosts of gut fungi, were analyzed for pesticide accumulation. Fungicides were detected in hosts from streams within agricultural watersheds but were not detected in hosts from reference streams. Gut fungi from agricultural sites exhibited decreased percent infestation, density and sporulation within the gut, and black fly tissues had elevated pesticide concentrations. Differences observed between the sites demonstrate a potential effect on this symbiotic system. Future research is needed to parse out the details of the complex biotic and abiotic relationships; however, these preliminary results indicate that impacts to nontarget organisms could have far-reaching consequences within aquatic ecosystems.

  5. Small and medium-sized enterprises’ exporting: Home and host country motivators effect on first and successive export venture decisions

    Directory of Open Access Journals (Sweden)

    Vassilios Stouraitis

    2016-06-01

    Full Text Available The aim of the paper is to investigate the internationalization (particularly exporting of small and medium-sized enterprises (SMEs taking a sample of United Kingdom (UK SMEs for the use in economic policy, academia and management. It focuses on the critical first and less risky step towards internationalization and separates the motivators into home country and host country. The paper investigates 44 specific, high impact, pre-selected exporting motivators from the literature and tests their effect on the firm’s initial export decision and latest (or sequential export decision. Results show that the first exporting choice affects later exporting choices and both are mostly affected by home country-specific, internal, motivators as opposed to host country-specific reactive motivators. In addition regionalization shows an association as European Union membership of the UK showed a relationship to subsequent entry mode choice. The paper’s results are of use to policy-makers and management.

  6. Non-Fickian diffusion with reaction in glassy polymers with swelling induced by the penetrant - Effects of consecutive and parallel reactions

    NARCIS (Netherlands)

    Kuipers, N.J M; Beenackers, A.A C M

    A mathematical model is presented for non-Fickian diffusion of a penetrant A into a granular glassy polymer containing a reactive group B, resulting in tile desired product P. Further, both a consecutive reaction between A and P (producing X) and a parallel reaction between A and C (producing Y) are

  7. Effect of elevating the skin temperature during topical ALA application on in vitro ALA penetration through mouse skin and in vivo PpIX production in human skin

    NARCIS (Netherlands)

    van den Akker, Johanna T. H. M.; Boot, Kristian; Vernon, David I.; Brown, Stanley B.; Groenendijk, Laurens; van Rhoon, Gerard C.; Sterenborg, Henricus J. C. M.

    2004-01-01

    An approach to induce increased protoporphyrin IX (PpIX) production in aminolevulinic acid (ALA)-based photodynamic therapy (PDT) of skin lesions is to elevate the skin temperature during topical ALA application. Increased skin temperature may increase the ( depth of) penetration of ALA into the

  8. Cooperative Transmembrane Penetration of Nanoparticles

    Science.gov (United States)

    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

  9. Effects of host deprivation and egg expenditure on the reproductive capacity of Mastrus ridibundus, an introduced parasitoid for the biological control of codling moth in California

    NARCIS (Netherlands)

    Hougardy, E.; Bezemer, T.M.; Mills, N.J.

    2005-01-01

    The effect of host deprivation and egg expenditure on egg load, realized fecundity, and parasitism of the ichneumonid Mastrus ridibundus, a gregarious parasitoid introduced for the control of codling moth in California, were investigated under laboratory conditions. Females deprived of hosts had a

  10. Effect of silver ions on the energy transfer from host defects to Tb ions in sol–gel silica glass

    Energy Technology Data Exchange (ETDEWEB)

    Abbass, Abd Ellateef [Department of Physics, University of the Free State, Bloemfontein (South Africa); Department of Physics, Sudan University of Science and Technology (Sudan); Swart, H.C. [Department of Physics, University of the Free State, Bloemfontein (South Africa); Kroon, R.E., E-mail: KroonRE@ufs.ac.za [Department of Physics, University of the Free State, Bloemfontein (South Africa)

    2015-04-15

    Plasmonic metal structures have been suggested to enhance the luminescence from rare-earth (RE) ions, but this enhancement is not yet well understood or applied to phosphor materials. Although some reports using Ag nanoparticles (NPs) in glass have attributed enhancement of RE emission to the strong electric fields associated with Ag NPs, it has also been proposed that the enhancement is instead due to energy transfer from Ag ions to RE ions. Our work using sol–gel silica shows a third possibility, namely that enhancement of the RE (e.g. Tb) emission is due to energy transfer from defects of the host material to the Tb ions, where the addition of Ag influences the silica host defects. The oxidation state of Ag as a function of annealing temperature was investigated by x-ray diffraction, transmission electron microscopy, UV–vis measurements and x-ray photoelectron spectroscopy, while optical properties were investigated using a Cary Eclipse fluorescence spectrophotometer or by exciting samples with a 325 nm He–Cd laser. The results showed that Ag ions have a significant effect on the silica host defects, which resulted in enhancement of the green Tb emission at 544 nm for non-resonant excitation using a wavelength of 325 nm. - Highlights: • Conversion of Ag ions to metallic nanoparticles after annealing of sol–gel silica. • Addition of Ag resulted in enhanced green luminescence from Tb ions in silica. • Enhancement is attributed to the effect of added Ag on the host defects of silica.

  11. Two mistletoes are too many?: Interspecific occurrence of mistletoes on the same host tree

    Directory of Open Access Journals (Sweden)

    Rafael Arruda

    2013-03-01

    Full Text Available Mistletoe can have a major impact on the fitness of the host plant. If there is more than one species of mistletoe on the same host tree, the overall impact might be amplified. We report the occurrence of more than one species of mistletoe on the same host tree. Although it is not a rule in the field, to our knowledge, there have been no studies of this topic. In most cases, two species of mistletoe were recorded on the same host tree, although we recorded three species of mistletoe on one occasion. This demonstrates that different species of mistletoe can be compatible with the same host species. Therefore, compatibility (structural and physiological might be an important factor for the occurrence of mistletoe. Recent studies have shown that if the mistletoe does not "recognize" the host species, the deposited seeds will germinate but the haustorium will not penetrate the host branch. This is probably the primary mechanism in the establishment of more than one species of mistletoe on the same host, which can trigger a cascade of harmful effects for the host species.

  12. The effect of nanocrystalline silicon host on magnetic properties of encapsulated iron oxide nanoparticles

    Science.gov (United States)

    Granitzer, P.; Rumpf, K.; Gonzalez-Rodriguez, R.; Coffer, J. L.; Reissner, M.

    2015-11-01

    The purpose of this work is a detailed comparison of the fundamental magnetic properties of nanocomposite systems consisting of Fe3O4 nanoparticle-loaded porous silicon as well as silicon nanotubes. Such composite structures are of potential merit in the area of magnetically guided drug delivery. For magnetic systems to be utilized in biomedical applications, there are certain magnetic properties that must be fulfilled. Therefore magnetic properties of embedded Fe3O4-nanoparticles in these nanostructured silicon host matrices, porous silicon and silicon nanotubes, are investigated. Temperature-dependent magnetic investigations have been carried out for four types of iron oxide particle sizes (4, 5, 8 and 10 nm). The silicon host, in interplay with the iron oxide nanoparticle size, plays a sensitive role. It is shown that Fe3O4 loaded porous silicon and SiNTs differ significantly in their magnetic behavior, especially the transition between superparamagnetic behavior and blocked state, due to host morphology-dependent magnetic interactions. Importantly, it is found that all investigated samples meet the magnetic precondition of possible biomedical applications of exhibiting a negligible magnetic remanence at room temperature.The purpose of this work is a detailed comparison of the fundamental magnetic properties of nanocomposite systems consisting of Fe3O4 nanoparticle-loaded porous silicon as well as silicon nanotubes. Such composite structures are of potential merit in the area of magnetically guided drug delivery. For magnetic systems to be utilized in biomedical applications, there are certain magnetic properties that must be fulfilled. Therefore magnetic properties of embedded Fe3O4-nanoparticles in these nanostructured silicon host matrices, porous silicon and silicon nanotubes, are investigated. Temperature-dependent magnetic investigations have been carried out for four types of iron oxide particle sizes (4, 5, 8 and 10 nm). The silicon host, in interplay

  13. Effects of near surface soil moisture profiles during evaporation on far-field ground-penetrating radar data: A numerical study

    KAUST Repository

    Moghadas, Davood

    2013-01-01

    We theoretically investigated the effect of vapor flow on the drying front that develops in soils when water evaporates from the soil surface and on GPR data. The results suggest the integration of the full-wave GPR model with a coupled water, vapor, and heat flow model to accurately estimate the soil hydraulic properties. We investigated the Effects of a drying front that emerges below an evaporating soil surface on the far-field ground-penetrating radar (GPR) data. First, we performed an analysis of the width of the drying front in soils with 12 different textures by using an analytical model. Then, we numerically simulated vertical soil moisture profiles that develop during evaporation for the soil textures. We performed the simulations using a Richards flow model that considers only liquid water flow and a model that considers coupled water, vapor, and heat flows. The GPR signals were then generated from the simulated soil water content profiles taking into account the frequency dependency of apparent electrical conductivity and dielectric permittivity. The analytical approach indicated that the width of the drying front at the end of Stage I of the evaporation was larger in silty soils than in other soil textures and smaller in sandy soils. We also demonstrated that the analytical estimate of the width of the drying front can be considered as a proxy for the impact that a drying front could have on far-field GPR data. The numerical simulations led to the conclusion that vapor transport in soil resulted in S-shaped soil moisture profiles, which clearly influenced the GPR data. As a result, vapor flow needs to be considered when GPR data are interpreted in a coupled inversion approach. Moreover, the impact of vapor flow on the GPR data was larger for silty than for sandy soils. These Effects on the GPR data provide promising perspectives regarding the use of radars for evaporation monitoring. © Soil Science Society of America 5585 Guilford Rd., Madison, WI

  14. Tilted Orientation of Photochromic Dyes with Guest-Host Effect of Liquid Crystalline Polymer Matrix for Electrical UV Sensing

    Directory of Open Access Journals (Sweden)

    Amid Ranjkesh

    2015-12-01

    Full Text Available We propose a highly oriented photochromic dye film for an ultraviolet (UV-sensing layer, where spirooxazine (SO derivatives are aligned with the liquid crystalline UV-curable reactive mesogens (RM using a guest-host effect. For effective electrical UV sensing with a simple metal-insulator-metal structure, our results show that the UV-induced switchable dipole moment amount of the SO derivatives is high; however, their tilting orientation should be controlled. Compared to the dielectric layer with the nearly planar SO dye orientation, the photochromic dielectric layer with the moderately tilted dye orientation shows more than seven times higher the UV-induced capacitance variation.

  15. The effect of time delay in plant--pathogen interactions with host demography.

    Science.gov (United States)

    Buonomo, Bruno; Cerasuolo, Marianna

    2015-06-01

    Botanical epidemic models are very important tools to study invasion, persistence and control of diseases. It is well known that limitations arise from considering constant infection rates. We replace this hypothesis in the framework of delay differential equations by proposing a delayed epidemic model for plant--pathogen interactions with host demography. Sufficient conditions for the global stability of the pathogen-free equilibrium and the permanence of the system are among the results obtained through qualitative analysis. We also show that the delay can cause stability switches of the coexistence equilibrium. In the undelayed case, we prove that the onset of oscillations may occur through Hopf bifurcation.

  16. Effects of Gut Microbiota Manipulation by Antibiotics on Host Metabolism in Obese Humans

    DEFF Research Database (Denmark)

    Reijnders, Dorien; Goossens, Gijs H; Hermes, Gerben D A

    2016-01-01

    , and whole-body insulin sensitivity were not altered at 8-week follow-up, despite a still considerably altered microbial composition, indicating that interference with adult microbiota by 7-day antibiotic treatment has no clinically relevant impact on metabolic health in obese humans.......The gut microbiota has been implicated in obesity and cardiometabolic diseases, although evidence in humans is scarce. We investigated how gut microbiota manipulation by antibiotics (7-day administration of amoxicillin, vancomycin, or placebo) affects host metabolism in 57 obese, prediabetic men...

  17. Implementation of a Permeable Membrane Insert-based Infection System to Study the Effects of Secreted Bacterial Toxins on Mammalian Host Cells.

    Science.gov (United States)

    Flaherty, Rebecca A; Lee, Shaun W

    2016-08-19

    Many bacterial pathogens secrete potent toxins to aid in the destruction of host tissue, to initiate signaling changes in host cells or to manipulate immune system responses during the course of infection. Though methods have been developed to successfully purify and produce many of these important virulence factors, there are still many bacterial toxins whose unique structure or extensive post-translational modifications make them difficult to purify and study in in vitro systems. Furthermore, even when pure toxin can be obtained, there are many challenges associated with studying the specific effects of a toxin under relevant physiological conditions. Most in vitro cell culture models designed to assess the effects of secreted bacterial toxins on host cells involve incubating host cells with a one-time dose of toxin. Such methods poorly approximate what host cells actually experience during an infection, where toxin is continually produced by bacterial cells and allowed to accumulate gradually during the course of infection. This protocol describes the design of a permeable membrane insert-based bacterial infection system to study the effects of Streptolysin S, a potent toxin produced by Group A Streptococcus, on human epithelial keratinocytes. This system more closely mimics the natural physiological environment during an infection than methods where pure toxin or bacterial supernatants are directly applied to host cells. Importantly, this method also eliminates the bias of host responses that are due to direct contact between the bacteria and host cells. This system has been utilized to effectively assess the effects of Streptolysin S (SLS) on host membrane integrity, cellular viability, and cellular signaling responses. This technique can be readily applied to the study of other secreted virulence factors on a variety of mammalian host cell types to investigate the specific role of a secreted bacterial factor during the course of infection.

  18. Effect of implantation site and injury condition on host response to human-derived fascia lata ECM in a rat model.

    Science.gov (United States)

    Leigh, Diane R; Baker, Andrew R; Mesiha, Mena; Rodriguez, E Rene; Tan, Carmela D; Walker, Esteban; Derwin, Kathleen A

    2012-03-01

    The host response and remodeling of ECM scaffolds are believed to be critical determinants of success or failure in repair or reconstructive procedures. Host response has been investigated in subcutaneous or abdominal wall implantation models. The extent to which evaluation of the host response to ECM intended for tendon or ligament repair should be performed in an orthotopic site is not known. This study compared the host response to human-derived fascia lata ECM among various implantation sites in the rat model. Results showed that a xenograft in the rat shoulder does not exhibit a different host response at 7 days from xenograft in the body wall, suggesting that either site may be appropriate to study the early host response to biologic grafts as well as the effect of various treatments aimed to modify the early host response. By 28 days, a xenograft in the rat shoulder does elicit a unique host response from that seen in the body wall. Therefore, it may be more appropriate to use an orthotopic shoulder model for investigating the long-term host response and remodeling of biologic grafts to be used for rotator cuff repair. Copyright © 2011 Orthopaedic Research Society.

  19. A Study on Factors Affecting Airborne LiDAR Penetration

    Directory of Open Access Journals (Sweden)

    Wei-Chen Hsu

    2015-01-01

    Full Text Available This study uses data from different periods, areas and parameters of airborne LiDAR (light detection and ranging surveys to understand the factors that influence airborne LiDAR penetration rate. A discussion is presented on the relationships between these factors and LiDAR penetration rate. The results show that the flight height above ground level (AGL does not have any relationship with the penetration rate. There are some factors that should have larger influence. For example, the laser is affected by a wet ground surface by reducing the number of return echoes. The field of view (FOV has a slightly negative correlation with the penetration rate, which indicates that the laser incidence angle close to zero should achieve the best penetration. The vegetation cover rate also shows a negative correlation with the penetration rate, thus bare ground and reduced vegetation in the aftermath of a typhoon also cause high penetration rate. More return echoes could be extracted from the full-waveform system, thereby effectively improving the penetration rate. This study shows that full-waveform LiDAR is an effective method for increasing the number of surface reflected echoes. This study suggests avoiding LiDAR survey employment directly following precipitation to prevent laser echo reduction.

  20. Trypanosoma evansi and surra: a review and perspectives on origin, history, distribution, taxonomy, morphology, hosts, and pathogenic effects.

    Science.gov (United States)

    Desquesnes, Marc; Holzmuller, Philippe; Lai, De-Hua; Dargantes, Alan; Lun, Zhao-Rong; Jittaplapong, Sathaporn

    2013-01-01

    Trypanosoma evansi, the agent of "surra," is a salivarian trypanosome, originating from Africa. It is thought to derive from Trypanosoma brucei by deletion of the maxicircle kinetoplastic DNA (genetic material required for cyclical development in tsetse flies). It is mostly mechanically transmitted by tabanids and stomoxes, initially to camels, in sub-Saharan area. The disease spread from North Africa towards the Middle East, Turkey, India, up to 53° North in Russia, across all South-East Asia, down to Indonesia and the Philippines, and it was also introduced by the conquistadores into Latin America. It can affect a very large range of domestic and wild hosts including camelids, equines, cattle, buffaloes, sheep, goats, pigs, dogs and other carnivores, deer, gazelles, and elephants. It found a new large range of wild and domestic hosts in Latin America, including reservoirs (capybaras) and biological vectors (vampire bats). Surra is a major disease in camels, equines, and dogs, in which it can often be fatal in the absence of treatment, and exhibits nonspecific clinical signs (anaemia, loss of weight, abortion, and death), which are variable from one host and one place to another; however, its immunosuppressive effects interfering with intercurrent diseases or vaccination campaigns might be its most significant and questionable aspect.

  1. Effects of Long-Term Starvation on a Host Bivalve (Codakia orbicularis, Lucinidae) and Its Symbiont Population▿

    Science.gov (United States)

    Caro, Audrey; Got, Patrice; Bouvy, Marc; Troussellier, Marc; Gros, Olivier

    2009-01-01

    The bivalve Codakia orbicularis, hosting sulfur-oxidizing gill endosymbionts, was starved (in artificial seawater filtered through a 0.22-μm-pore-size membrane) for a long-term experiment (4 months). The effects of starvation were observed using transmission electron microscopy, fluorescence in situ hybridization and catalyzed reporter deposition (CARD-FISH), and flow cytometry to monitor the anatomical and physiological modifications in the gill organization of the host and in the symbiotic population housed in bacteriocytes. The abundance of the symbiotic population decreased through starvation, with a loss of one-third of the bacterial population each month, as shown by CARD-FISH. At the same time, flow cytometry revealed significant changes in the physiology of symbiotic cells, with a decrease in cell size and modifications to the nucleic acid content, while most of the symbionts maintained a high respiratory activity (measured using the 5-cyano-2,3-ditolyl tetrazolium chloride method). Progressively, the number of symbiont subpopulations was reduced, and the subsequent multigenomic state, characteristic of this symbiont in freshly collected clams, turned into one and five equivalent genome copies for the two remaining subpopulations after 3 months. Concomitant structural modifications appeared in the gill organization. Lysosymes became visible in the bacteriocytes, while large symbionts disappeared, and bacteriocytes were gradually replaced by granule cells throughout the entire lateral zone. Those data suggested that host survival under these starvation conditions was linked to symbiont digestion as the main nutritional source. PMID:19346359

  2. Trypanosoma evansi and Surra: A Review and Perspectives on Origin, History, Distribution, Taxonomy, Morphology, Hosts, and Pathogenic Effects

    Directory of Open Access Journals (Sweden)

    Marc Desquesnes

    2013-01-01

    Full Text Available Trypanosoma evansi, the agent of “surra,” is a salivarian trypanosome, originating from Africa. It is thought to derive from Trypanosoma brucei by deletion of the maxicircle kinetoplastic DNA (genetic material required for cyclical development in tsetse flies. It is mostly mechanically transmitted by tabanids and stomoxes, initially to camels, in sub-Saharan area. The disease spread from North Africa towards the Middle East, Turkey, India, up to 53° North in Russia, across all South-East Asia, down to Indonesia and the Philippines, and it was also introduced by the conquistadores into Latin America. It can affect a very large range of domestic and wild hosts including camelids, equines, cattle, buffaloes, sheep, goats, pigs, dogs and other carnivores, deer, gazelles, and elephants. It found a new large range of wild and domestic hosts in Latin America, including reservoirs (capybaras and biological vectors (vampire bats. Surra is a major disease in camels, equines, and dogs, in which it can often be fatal in the absence of treatment, and exhibits nonspecific clinical signs (anaemia, loss of weight, abortion, and death, which are variable from one host and one place to another; however, its immunosuppressive effects interfering with intercurrent diseases or vaccination campaigns might be its most significant and questionable aspect.

  3. Morphometric Analysis of the Host Effect on Phenotypical Variation of Belminus ferroae (Hemiptera: Triatominae

    Directory of Open Access Journals (Sweden)

    Claudia Magaly Sandoval Ramirez

    2015-01-01

    Full Text Available The Triatominae subfamily includes hematophagous insects, well known for their role as vectors for the Trypanosoma cruzi parasite, etiologic agent of Chagas’ disease. Belminus ferroae is a triatomine that showed an increased demographic fitness when cockroaches were used as hosts. Here we compare the centroid size (CS and wing shape between B. ferroae parents and three successive generations (O1, O2, and O3 of their offspring fed on cockroaches or mice under laboratory conditions. Morphometric analysis of the wings bugs fed on cockroaches showed a significant reduction in CS in both sexes among all generations. Sexual size dimorphism (SSD was observed in the insects fed on cockroaches (O2 and O3, as well as those bugs fed on mice (O2. Differences in the shape of wings were observed between parental and offspring wings when fed on mice, but not in males (O1, O2, and O3 or females (O1 and O2 fed on cockroaches. There was a greater wing shape similarity between the cockroach-fed offspring and their parents according to the Mahalanobis distances. Our results support the idea of higher adaptation of this Triatominae with arthropod hosts.

  4. Effects of Genetic Variation on the E. coli Host-Circuit Interface

    Directory of Open Access Journals (Sweden)

    Stefano Cardinale

    2013-07-01

    Full Text Available Predictable operation of engineered biological circuitry requires the knowledge of host factors that compete or interfere with designed function. Here, we perform a detailed analysis of the interaction between constitutive expression from a test circuit and cell-growth properties in a subset of genetic variants of the bacterium Escherichia coli. Differences in generic cellular parameters such as ribosome availability and growth rate are the main determinants (89% of strain-specific differences of circuit performance in laboratory-adapted strains but are responsible for only 35% of expression variation across 88 mutants of E. coli BW25113. In the latter strains, we identify specific cell functions, such as nitrogen metabolism, that directly modulate circuit behavior. Finally, we expose aspects of carbon metabolism that act in a strain- and sequence-specific manner. This method of dissecting interactions between host factors and heterologous circuits enables the discovery of mechanisms of interference necessary for the development of design principles for predictable cellular engineering.

  5. Revisiting The First Galaxies: The effects of Population III stars on their host galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Muratov, Alexander L. [U. Michigan, Dept. Astron.; Gnedin, Oleg Y. [U. Michigan, Dept. Astron.; Gnedin, Nickolay Y. [Chicago U., Astron. Astrophys. Ctr.; Zemp, Marcel [Beijing, KITPC

    2013-07-12

    We revisit the formation and evolution of the first galaxies using new hydrodynamic cosmological simulations with the adaptive refinement tree code. Our simulations feature a recently developed model for H2 formation and dissociation, and a star formation recipe that is based on molecular rather than atomic gas. Here, we develop and implement a recipe for the formation of metal-free Population III (Pop III) stars in galaxy-scale simulations that resolve primordial clouds with sufficiently high density. We base our recipe on the results of prior zoom-in simulations that resolved the protostellar collapse in pre-galactic objects. We find the epoch during which Pop III stars dominated the energy and metal budget of the first galaxies to be short-lived. Galaxies that host Pop III stars do not retain dynamical signatures of their thermal and radiative feedback for more than 108 years after the lives of the stars end in pair-instability supernovae, even when we consider the maximum reasonable efficiency of the feedback. Though metals ejected by the supernovae can travel well beyond the virial radius of the host galaxy, they typically begin to fall back quickly, and do not enrich a large fraction of the intergalactic medium. Galaxies with a total mass in excess of 3 × 106 M re-accrete most of their baryons and transition to metal-enriched Pop II star formation.

  6. Effects of Feeding on Different Host Plants and Diets on Bradysia Odoriphaga Population Parameters and Tolerance to Heat and Insecticides.

    Science.gov (United States)

    Zhu, Guodong; Luo, Yin; Xue, Ming; Zhao, Haipeng; Sun, Xia; Wang, Xinhui

    2017-10-17

    Bradysia odoriphaga Yang et Zhang, the Chinese chive root maggot, is a devastating pest of agricultural plants causing significant losses in vegetable crops, edible mushrooms, and humus. To determine the effects of feeding on different host plants and diets on the life parameters of B. odoriphaga and its tolerance to stressful conditions, we analyzed the life-table data of B. odoriphaga reared on Chinese chive (Allium hookeri), Welsh onion (Allium fistulosum), garlic (Allium sativum), oyster mushroom (Pleurotus ostreatus), and humus and assayed its tolerance to heat and insecticides. Furthermore, we assayed the physiological responses of B. odoriphaga reared on different hosts. Development from egg to adult was successfully completed on five hosts. Life table indicated that when reared on Chinese chive and oyster mushroom, B. odoriphaga showed better life parameters (shorter development time, higher survival rate, and fecundity) than on humus and garlic. However, B. odoriphaga larvae fed on humus and garlic better tolerated heat and insecticides than those that were fed Chinese chive and oyster mushroom; larvae survived longer at 38 and 40°C heat shock and at higher insecticide doses. Activities of antioxidant and detoxification enzymes varied significantly in larvae fed on different hosts. Catalase, superoxide dismutase, glutathione S-transferase, and carboxylesterase activities were higher in larva reared on garlic and humus than on Chinese chive and oyster mushroom. These findings indicated that B. odoriphaga preferred liliaceous vegetables and mushroom, and their tolerance against stress increased when reared on humus and garlic. Such basic information can promote targeted pest management in different agricultural fields and allow better understanding of the acclimatization strategy of B. odoriphaga. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please email

  7. Microbial Mitigation-Exacerbation Continuum: A novel framework for microbiome effects on hosts in the face of stress.

    Science.gov (United States)

    David, Aaron S; Thapa-Magar, Khum B; Afkhami, Michelle E

    2018-01-18

    A key challenge to understanding microbiomes and their role in ecological processes is contextualizing their effects on host organisms, particularly when faced with environmental stress. One influential theory, the Stress Gradient Hypothesis, might predict that the frequency of positive interactions increases with stressful conditions such that microbial taxa would mitigate harmful effects on host performance. Yet, equally plausible is that microbial taxa could exacerbate these effects. Here, we introduce the "Mitigation-Exacerbation Continuum" as a novel framework to conceptualize microbial mediation of stress. We (1) use this continuum to quantify microbial mediation of stress for six plant species, and (2) test the association between these continuum values and natural species abundance. We factorially manipulated a common stress (allelopathy) and the presence of soil microbes to quantify microbial effects in benign and stressed environments for two critical early life-history metrics, seed germination and seedling biomass. Although we found evidence of both mitigation and exacerbation among the six species, exacerbation was more common. Across species, the degree of microbial-mediated effects on germination explained >80% of the variation of natural field abundances. Our results suggest a critical role of soil microbes in mediating plant stress responses, and a potential microbial mechanism underlying species abundance. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  8. Host resistance and tolerance of parasitic gut worms depend on resource availability.

    Science.gov (United States)

    Knutie, Sarah A; Wilkinson, Christina L; Wu, Qiu Chang; Ortega, C Nicole; Rohr, Jason R

    2017-04-01

    Resource availability can significantly alter host-parasite dynamics. Abundant food can provide more resources for hosts to resist infections, but also increase host tolerance of infections by reducing competition between hosts and parasites for food. Whether abundant food favors host resistance or tolerance (or both) might depend on the type of resource that the parasite exploits (e.g., host tissue vs. food), which can vary based on the stage of infection. In our study, we evaluated how low and high resource diets affect Cuban tree frog (Osteopilus septentrionalis) resistance and tolerance of a skin-penetrating, gut nematode Aplectana sp. at each stage of the infection. Compared to a low resource diet, a high resource diet enhanced frog resistance to worm penetration and tolerance while worms traveled to the gut. In contrast, a low resource diet increased resistance to establishment of the infection. After the infection established and worms could access food resources in the gut, a high resource diet enhanced host tolerance of parasites. On a high resource diet, parasitized frogs consumed significantly more food than non-parasitized frogs; when food was then restricted, mass of non-parasitized frogs did not change, whereas mass of parasitized frogs decreased significantly. Thus, a high resource diet increased frog tolerance of established worms because frogs could fully compensate for energy lost to the parasites. Our study shows that host-parasite dynamics are influenced by the effect of resource availability on host resistance and tolerance, which depends on when parasites have access to food and the stage of infection.

  9. Mistletoe ecophysiology: Host-parasite interactions

    Science.gov (United States)

    G. Glatzel; B. W. Geils

    2009-01-01

    Mistletoes are highly specialized perennial flowering plants adapted to parasitic life on aerial parts of their hosts. In our discussion on the physiological interactions between parasite and host, we focus on water relations, mineral nutrition, and the effect of host vigour. When host photosynthesis is greatest, the xylem water potential of the host is most negative....

  10. Complex interactive effects of water mold, herbicide, and the fungus Batrachochytrium dendrobatidis on Pacific treefrog Hyliola regilla hosts.

    Science.gov (United States)

    Romansic, John M; Johnson, James E; Wagner, R Steven; Hill, Rebecca H; Gaulke, Christopher A; Vredenburg, Vance T; Blaustein, Andrew R

    2017-03-21

    Infectious diseases pose a serious threat to global biodiversity. However, their ecological impacts are not independent of environmental conditions. For example, the pathogenic fungus Batrachochytrium dendrobatidis (Bd), which has contributed to population declines and extinctions in many amphibian species, interacts with several environmental factors to influence its hosts, but potential interactions with other pathogens and environmental contaminants are understudied. We examined the combined effects of Bd, a water mold (Achlya sp.), and the herbicide Roundup® Regular (hereafter, Roundup®) on larval Pacific treefrog Hyliola regilla hosts. We employed a 2 wk, fully factorial laboratory experiment with 3 ecologically realistic levels (0, 1, and 2 mg l-1 of active ingredient) of field-formulated Roundup®, 2 Achlya treatments (present and absent), and 2 Bd treatments (present and absent). Our results were consistent with sublethal interactive effects involving all 3 experimental factors. When Roundup® was absent, the proportion of Bd-exposed larvae infected with Bd was elevated in the presence of Achlya, consistent with Achlya acting as a synergistic cofactor that facilitated the establishment of Bd infection. However, this Achlya effect became nonsignificant at 1 mg l-1 of the active ingredient of Roundup® and disappeared at the highest Roundup® concentration. In addition, Roundup® decreased Bd loads among Bd-exposed larvae. Our study suggests complex interactive effects of a water mold and a contaminant on Bd infection in amphibian hosts. Achlya and Roundup® were both correlated with altered patterns of Bd infection, but in different ways, and Roundup® appeared to remove the influence of Achlya on Bd.

  11. No measurable adverse effects of Lassa, Morogoro and Gairo arenaviruses on their rodent reservoir host in natural conditions.

    Science.gov (United States)

    Mariën, Joachim; Borremans, Benny; Gryseels, Sophie; Soropogui, Barré; De Bruyn, Luc; Bongo, Gédéon Ngiala; Becker-Ziaja, Beate; de Bellocq, Joëlle Goüy; Günther, Stephan; Magassouba, N'Faly; Leirs, Herwig; Fichet-Calvet, Elisabeth

    2017-04-27

    In order to optimize net transmission success, parasites are hypothesized to evolve towards causing minimal damage to their reservoir host while obtaining high shedding rates. For many parasite species however this paradigm has not been tested, and conflicting results have been found regarding the effect of arenaviruses on their rodent host species. The rodent Mastomys natalensis is the natural reservoir host of several arenaviruses, including Lassa virus that is known to cause Lassa haemorrhagic fever in humans. Here, we examined the effect of three arenaviruses (Gairo, Morogoro and Lassa virus) on four parameters of wild-caught Mastomys natalensis: body mass, head-body length, sexual maturity and fertility. After correcting for the effect of age, we compared these parameters between arenavirus-positive (arenavirus RNA or antibody) and negative animals using data from different field studies in Guinea (Lassa virus) and Tanzania (Morogoro and Gairo viruses). Although the sample sizes of our studies (1297, 749 and 259 animals respectively) were large enough to statistically detect small differences in body conditions, we did not observe any adverse effects of these viruses on Mastomys natalensis. We did find that sexual maturity was significantly positively related with Lassa virus antibody presence until a certain age, and with Gairo virus antibody presence in general. Gairo virus antibody-positive animals were also significantly heavier and larger than antibody-free animals. Together, these results suggest that the pathogenicity of arenaviruses is not severe in M. natalensis, which is likely to be an adaptation of these viruses to optimize transmission success. They also suggest that sexual behaviour might increase the probability of M. natalensis to become infected with arenaviruses.

  12. Penetration of Photovoltaics in Greece

    OpenAIRE

    Eugenia Giannini; Antonia Moropoulou; Zacharias Maroulis; Glykeria Siouti

    2015-01-01

    Recently, an interesting experiment was completed in Greece concerning photovoltaic penetration into the electricity production sector. Based on the relevant laws and in accordance to the related European directives, an explosive penetration process was completed in less than three years, resulting in a 7% share of photovoltaics in electricity production instead of the previous negligible share. The legislation was based on licensing simplification and generous feed-in-tariffs. This approach ...

  13. Corneal epithelium following penetrating keratoplasty.

    OpenAIRE

    Tsubota, K; Mashima, Y; Murata, H; Yamada, M.; Sato, N.

    1995-01-01

    AIMS--This study was designed to observe any changes to the corneal epithelium after penetrating keratoplasty. METHODS--The corneal epithelia of 26 patients were observed by specular microscopy 1 week, 1 month, 3 months, and 6 months following penetrating keratoplasty. RESULTS--After re-epithelialisation was confirmed by biomicroscopy 1 week after surgery, specular microscopy revealed many abnormal cells, including spindle shaped cells, nucleated cells, large cells, as well as irregular cell ...

  14. Enhancing Tumor Penetration of Nanomedicines

    OpenAIRE

    Sun, Qingxue; Ojha, Tarun; Kiessling, Fabian; Lammers, Twan; Shi, Yang

    2017-01-01

    Tumor-targeted nanomedicines have been extensively applied to alter the drawbacks and enhance the efficacy of chemotherapeutics. Despite the large number of preclinical nanomedicine studies showing initial success, their therapeutic benefit in the clinic has been rather modest, which is partially due to the inefficient tumor penetration caused by tumor microenvironment (high density of cells and extracellular matrix, increased interstitial fluid pressure). Furthermore, tumor penetration of na...

  15. Why stay in a bad relationship? The effect of local host phenology on a generalist butterfly feeding on a low-ranked host.

    Science.gov (United States)

    Audusseau, Hélène; de la Paz Celorio-Mancera, Maria; Janz, Niklas; Nylin, Sören

    2016-06-29

    In plant-feeding insects, the evolutionary retention of polyphagy remains puzzling. A better understanding of the relationship between these organisms and changes in the metabolome of their host plants is likely to suggest functional links between them, and may provide insights into how polyphagy is maintained. We investigated the phenological change of Cynoglossum officinale, and how a generalist butterfly species, Vanessa cardui, responded to this change. We used untargeted metabolite profiling to map plant seasonal changes in both primary and secondary metabolites. We compared these data to differences in larval performance on vegetative plants early and late in the season. We also performed two oviposition preference experiments to test females' ability to choose between plant developmental stages (vegetative and reproductive) early and late in the season. We found clear seasonal changes in plant primary and secondary metabolites that correlated with larval performance. The seasonal change in plant metabolome reflected changes in both nutrition and toxicity and resulted in zero survival in the late period. However, large differences among families in larval ability to feed on C. officinale suggest that there is genetic variation for performance on this host. Moreover, females accepted all plants for oviposition, and were not able to discriminate between plant developmental stages, in spite of the observed overall differences in metabolite profile potentially associated with differences in suitability as larval food. In V. cardui, migratory behavior, and thus larval feeding times, are not synchronized with plant phenology at the reproductive site. This lack of synchronization, coupled with the observed lack of discriminatory oviposition, obviously has potential fitness costs. However, this "opportunistic" behavior may as well function as a source of potential host plant evolution, promoting for example the acceptance of new plants.

  16. [Children and adolescents from elsewhere: the violence experienced in their host society and the effects on their health, a literature].

    Science.gov (United States)

    Fournier, Claudia; Hamelin Brabant, Louise; Damant, Dominique; Lessard, Geneviève; Lapierre, Simon; Dubé-Quenum, Mélissa

    2014-01-10

    This integrative literature review aims to present a comprehensive portrayal of social violence experienced by first-generation immigrant children and adolescents, and its effects on their health and well-being. A French and English languages literature search was conducted in eight databases, without restrictions on dates of publication. Thirty studies were selected. Results were summarized according to three aspects: 1) types of violence experienced by young immigrants; 2) conditions under which this violence occurs; 3) effects of such violence on the health and well-being of young immigrants. Immigrant children and adolescents can experience various forms of physical, verbal, and relational violence. This violence seems to be mostly instigated by their peers and it has mainly been studied in terms of discrimination. Victimization may vary depending on factors such as ethnic composition of schools or time of residence in the host society. Violence may have many effects on mental health of immigrant youth: it is associated with both increased psychopathological symptoms and poorer mental health. Finally, the experience of violence is related to a more negative attitude of young immigrants toward their host society and a more positive attitude toward their own cultural community. In addition to its having numerous adverse effects on their mental and social health and well-being, violence may prove to be a key factor in the experience of marginalization of immigrant youth. We propose certain research avenues to explore.

  17. A Unified Model Considering Effects of Droplet Break-Up and Air Entrainment at the Initial Stage of Fuel Spray Penetration

    Directory of Open Access Journals (Sweden)

    S. Jafarmadar

    2014-01-01

    Full Text Available This paper proposes a new unified single model that considers droplet break-up and air entrainment impact on three flow regimes (namely, Stokes, Allen, and Newton in the initial stage of fuel spray penetration. Homotopy perturbation method was used to obtain semianalytical solutions of unified single model on diesel fuel’s spray penetration when the influence of air entrainment is small (up to 0.1-0.2 ms after the start of injection. It is demonstrated that the applied analytical method is very straightforward in comparison with existing techniques. Furthermore, it is decidedly effectual in terms of accuracy and rapid convergence. The formulation of the problem is presented in the text as well as the analytical and numerical procedures.

  18. CELL PENETRATION BY ACIDS : VI. THE CHLOROACETIC ACIDS.

    Science.gov (United States)

    Crozier, W J

    1922-09-20

    Measurements of the penetration of tissue from Chromodoris zebra are believed to show that a determining factor in penetration involves the establishment of a critical pH (near 3.5) in relation to superficial cell proteins. The rapidity with which this state is produced depends upon acid strength, and upon some property of the acid influencing the speed of absorption; hence it is necessary to compare acids within groups of chemical relationship. The actual speed of penetration observed with any acid is dependent upon two influences: preliminary chemical combination with the outer protoplasm, followed by diffusion. The variation of the temperature coefficient of penetration velocity with the concentration of acid, and the effect of size (age) of individual providing the tissue sample agree in demonstrating the significant part played by diffusion. In comparing different acids, however, their mode of chemical union with the protoplasm determines the general order of penetrating ability.

  19. The cone penetration test in unsaturated silty sands

    Directory of Open Access Journals (Sweden)

    Yang Hongwei

    2016-01-01

    Full Text Available Very little is known about how to interpret the cone penetration test (CPT when performed in unsaturated soils. The few published studies on the CPT in unsaturated soils have focused on either clean sands or a silt. In this study new results of laboratory-controlled CPTs in an unsaturated silty sand are presented. The silty sand exhibits hydraulic hysteresis and suction hardening. Suction is observed to have a pronounced affect on measured cone penetration resistance. For an isotropic net confining stress of 60 kPa it is observed that higher suctions give rise to cone penetration resistances that are 50% larger than those for lower suctions. A semi-theoretical correlation is presented that links measured cone penetration resistances to initial relative density and mean effective stress. For this silty sand it is shown that failing to account for suction may result in significant overestimations and unsafe predictions of soil properties from measured cone penetration resistances.

  20. Conceptualizing knowledge transfer between expatriates and host country nationals: The mediating effect of social capital

    Directory of Open Access Journals (Sweden)

    Maimunah Ismail

    2015-12-01

    Full Text Available This paper aims to propose a conceptual model of knowledge transfer by relating two specific personal factors of expatriate and host country national (HCN dyads as antecedents of knowledge transfer, and mediated by social capital factors. An intensive literature review method was employed to identify and analyse relevant literatures. The paper used a dyadic bi-directional approach in theorizing knowledge transfer by integrating the social capital theory, and the anxiety and uncertainty management theory. The paper considers two personal factors (cultural intelligence and knowledge-seeking behaviour and two social capital variables (trust and shared vision as mediators of knowledge transfer. Upon model validation, the paper could offer practical interventions for human resource practitioners and managers to assist multinational corporations towards managing knowledge transfer involving expatriates and HCNs.

  1. The effect of formulation on the penetration of coated and uncoated zinc oxide nanoparticles into the viable epidermis of human skin in vivo.

    Science.gov (United States)

    Leite-Silva, Vânia R; Le Lamer, Marina; Sanchez, Washington Y; Liu, David C; Sanchez, Washington H; Morrow, Isabel; Martin, Darren; Silva, Heron D T; Prow, Tarl W; Grice, Jeffrey E; Roberts, Michael S

    2013-06-01

    The use of nanoparticulate zinc oxide (ZnO-NP) in sunscreens and other cosmetic products has raised public health concerns. The two key issues are the extent of exposure to ZnO-NP and the likely hazard after the application of ZnO-NP in sunscreen and cosmetic products to humans in vivo. Our aims were to assess exposure by the extent of ZnO-NP penetration into the viable epidermis and hazard by changes in the viable epidermal redox state for a number of topical products. Of particular interest is the role of the particle coating, formulation used, and the presence of any enhancers. Multiphoton tomography with fluorescence lifetime imaging microscopy (MPT-FLIM) was used to simultaneously observe ZnO-NP penetration and potential metabolic changes within the viable epidermis of human volunteers after topical application of various ZnO-NP products. Coated and uncoated ZnO-NP remained in the superficial layers of the SC and in the skin furrows. We observed limited penetration of coated ZnO-NP dispersed in a water-in-oil emulsion formulation, which was predominantly localized adjacent to the skin furrow. However, the presence of ZnO-NP in the viable epidermis did not alter the metabolic state or morphology of the cells. In summary, our data suggest that some limited penetration of coated and uncoated ZnO-NP may occur into viable stratum granulosum epidermis adjacent to furrows, but that the extent is not sufficient to affect the redox state of those viable cells. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  2. Solution of the direct problem of induction logging for bed composites with penetration of solution without consideration of the skin effect

    Energy Technology Data Exchange (ETDEWEB)

    Vaksman, K.G.; Afonina, N.M.; Plyusnin, M.I.

    1981-01-01

    Discussed is the solution of the direct problem of induction logging according to the theory of Doll, and the asymptotic formulas are derived for calculating the geometric factors of the beds which permit an increase in the speed and rate of the calculations. A program is described for determining the apparent resistances by any infrared probe in the cross section containing any number of beds with a zone of penetration.

  3. The effect of host factors and capsule composition on the cellular overgrowth on implanted alginate capsules.

    Science.gov (United States)

    King, A; Sandler, S; Andersson, A

    2001-12-05

    Microencapsulation of islets of Langerhans in alginate/poly-L-lysine (PLL)/alginate capsules may provide a method for transplantation in the absence of immunosuppression. The aim of this study was to investigate the problem of overgrowth on implanted capsules with regard to the composition of the capsules and host factors such as cytokine and nitric oxide production. Empty capsules were implanted to C57BL/6 mice for 1, 3, 7, or 28 days. Glucose oxidation rates showed the metabolic activity of the cellular overgrowth on retrieved capsules. DNA content, histological score, and retrieval rates were also measured to assess the overgrowth. It was noted that the pericapsular host reaction arose by day 7 and had not increased further by day 28. Capsules of varying alginate compositions and different concentrations of PLL were implanted for 7 days to either C57BL/6 or Balb/c mice. Capsules were also implanted to mice lacking the inducible nitric oxide synthase enzyme. Glucose oxidation rates, DNA content, and histological score were positively correlated to each other and negatively correlated to retrieval rates. The pericapsular reaction was reduced if PLL was omitted from the capsule or if a high mannuronic acid alginate was used. Balb/c mice had reduced cellular overgrowth on implanted capsules and had reduced mRNA expression of interleukin-1 beta and tumor necrosis factor-alpha in their peritoneal macrophages. The capsular overgrowth seemed more severe in animals lacking inducible nitric oxide synthase compared with wild-type controls. It is concluded that alginate composition, PLL, and recipient factors such as nitric oxide production and cytokine expression affect the cellular overgrowth on implanted alginate capsules. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 57: 374-383, 2001

  4. Herbivore Diet Breadth and Host Plant Defense Mediate the Tri-Trophic Effects of Plant Toxins on Multiple Coccinellid Predators.

    Directory of Open Access Journals (Sweden)

    Angelos Katsanis

    Full Text Available Host plant defenses are known to cascade up food chains to influence herbivores and their natural enemies, but how herbivore and predator traits and identity mediate such tri-trophic dynamics is largely unknown. We assessed the influence of plant defense on aphid and coccinellid performance in laboratory trials with low- vs. high-glucosinolate varieties of Brassica napus, a dietary specialist (Brevicoryne brassicae and generalist (Myzus persicae aphid, and five species of aphidophagous coccinellids. The performance of the specialist and generalist aphids was similar and unaffected by variation in plant defense. Aphid glucosinolate concentration and resistance to predators differed by aphid species and host plant defense, and these effects acted independently. With respect to aphid species, the dietary generalist aphid (vs. specialist had 14% lower glucosinolate concentration and coccinellid predators ate three-fold more aphids. With respect to host plant variety, the high-glucosinolate plants (vs. low increased aphid glucosinolate concentration by 21%, but had relatively weak effects on predation by coccinellids and these effects varied among coccinellid species. In turn, coccinellid performance was influenced by the interactive effects of plant defense and aphid species, as the cascading, indirect effect of plant defense was greater when feeding upon the specialist than generalist aphid. When feeding upon specialist aphids, low- (vs. high- glucosinolate plants increased coccinellid mass gain by 78% and accelerated development by 14%. In contrast, when feeding upon generalist aphids, low- (vs. high- glucosinolate plants increased coccinellid mass gain by only 11% and had no detectable effect on development time. These interactive effects of plant defense and aphid diet breadth on predator performance also varied among coccinellid species; the indirect negative effects of plant defenses on predator performance was consistent among the five

  5. Flux penetrations into two- and three-dimensional nanostructured superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tamegai, T., E-mail: tamegai@ap.t.u-tokyo.ac.jp [Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Tsuchiya, Y.; Tada, S.; Ibuka, J.; Mine, A.; Pyon, S. [Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Mawatari, Y.; Nagasawa, S.; Hidaka, M.; Maezawa, M. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan)

    2014-08-15

    Highlights: • Flux penetrations into two- and three-dimensional nanostructured superconductors are observed by magneto-optical imaging. • In two-dimensional superconducting networks with square holes on square lattice, anomalous diagonal penetrations are observed. • In three-dimensional superconducting shifted strip arrays, various forms of vortex avalanches are observed. - Abstract: We have fabricated two- and three-dimensional nanostructured superconductors, and observed vortex penetrations by magneto-optical imaging. In the case of two-dimensional superconducting networks with square holes on a square lattice, anomalous diagonal penetrations are widely observed. Two kinds of diagonal vortex penetrations at high and low temperatures have been interpreted as originating from the repulsive interaction of vortices and sharp fan-shaped vortex penetration from the corners of the square holes, respectively. In the case of three-dimensional stack of superconducting strip arrays with double and triple layers, vortex avalanches have been observed in a wide temperature and dimension ranges due to enhanced demagnetization effect. While spotlike avalanches are observed when the overlap of strips is small, anomalous linear avalanches traversing many strips in different layers are observed when the overlap is large. In triple-layer strip arrays, in addition to the spotlike and linear avalanches, vortex penetrations along the line of strips are also observed. Origins of the anomalous diagonal penetration and vortex avalanches are discussed.

  6. Skin Penetration Enhancement by Natural Oils for Dihydroquercetin Delivery.

    Science.gov (United States)

    Čižinauskas, Vytis; Elie, Nicolas; Brunelle, Alain; Briedis, Vitalis

    2017-09-12

    Natural oils are commonly used in topical pharmaceutical formulations as emulsifiers, stabilizers or solubility enhancers. They are presented as safe and inert components, mainly used for formulation purposes. It is confirmed that natural oils can affect the skin penetration of various substances. Fatty acids are mainly responsible for this effect. Current understanding lacks reliable scientific data on penetration of natural oils into the skin and their skin penetration enhancement potential. In the current study, fatty acid content analysis was used to determine the principal fatty acids in soybean, olive, avocado, sea-buckthorn pulp, raspberry seed and coconut oils. Time of flight secondary ion mass spectrometry bioimaging was used to determine the distribution of these fatty acids in human skin ex vivo after application of the oils. Skin penetration enhancement ratios were determined for a perspective antioxidant compound dihydroquercetin. The results demonstrated skin penetration of fatty acids from all oils tested. Only soybean and olive oils significantly increased the skin distribution of dihydroquercetin and can be used as skin penetration enhancers. However, no correlation can be determined between the fatty acids' composition and skin penetration enhancement using currently available methodological approaches. This indicates that potential chemical penetration enhancement should be evaluated during formulation of topically applied products containing natural oils.

  7. The Effect of Donor Age on Penetrating Keratoplasty for Endothelial Disease: Graft Survival after 10 Years in the Cornea Donor Study

    Science.gov (United States)

    Mannis, Mark J.; Holland, Edward J; Gal, Robin L.; Dontchev, Mariya; Kollman, Craig; Raghinaru, Dan; Dunn, Steven P.; Schultze, Robert L.; Verdier, David D.; Lass, Jonathan H.; Raber, Irving M.; Sugar, Joel; Gorovoy, Mark S.; Sugar, Alan; Stulting, R. Doyle; Montoya, Monty M.; Penta, Jeffrey G.; Benetz, Beth Ann; Beck, Roy W.

    2013-01-01

    Objective To determine whether the 10-year success rate of penetrating keratoplasty for corneal endothelial disorders is associated with donor age. Design Multi-center, prospective, double-masked clinical trial Participants 1090 participants undergoing penetrating keratoplasty at 80 sites for Fuchs’ dystrophy (62%), pseudophakic/aphakic corneal edema (34%) or another corneal endothelial disorder (4%) and followed for up to 12 years. Methods Forty-three eye banks provided corneas from donors 12 to 75 years old, using a randomized approach to assign donor corneas to study participants, without respect to recipient factors. Surgery and postoperative care were performed according to the surgeons’ usual routines. Main Outcome Measure Graft failure defined as a regraft or in the absence of a regraft, a cloudy cornea that was sufficiently opaque to compromise vision for 3 consecutive months. Results In the primary analysis, the 10-year success rate was 77% for 707 corneas from donors 12 to 65 years old compared with 71% for 383 donors 66 to 75 years old (difference = +6%, 95% confidence interval = −1% to +12%, P=0.11). When analyzed as a continuous variable, higher donor age was associated with lower graft success after the first 5 years (Pcorneas in the United States available for transplant, the Cornea Donor Study results indicate that donor age is not an important factor in most penetrating keratoplasties for endothelial disease. PMID:24246825

  8. Effects of tensile strain on the peculiarities of PEO penetration into the nanoporous structure of PET deformed via the crazing mechanism.

    Science.gov (United States)

    Rukhlya, E G; Yarysheva, L M; Volynskii, A L; Bakeev, N F

    2016-04-14

    Solvent crazing involves the development of a highly dispersed fibrillar-porous structure with dimensions of pores and craze fibrils of about 2-20 nm, and crazing by itself can be treated as a universal method for the development of nanoscale porosity. The penetration and release of poly(ethylene oxide) macromolecules into and from the crazes during the development of the nanoporous structure of poly(ethylene terephthalate) have been studied. In particular, PET has been deformed in dilute or semidilute (unentangled as well as entangled) solutions of PEO (a Mw of 4 and 40 kDa) via the mechanism of solvent crazing. Hydrodynamic coil radii Rh, blob sizes ξ, and concentration ranges (crossover and entanglement concentrations) have been determined for the PEO solutions. The evolution of the craze structure (change in porosity W and pore diameters d) has been described as a function of the tensile strain of PET during its drawing in an adsorption-active medium and in the PEO solutions. PEO has been shown to penetrate into the nanoporous structure of the crazes under the conditions corresponding to Rh≤d and ξ PEO adsorption at the highly developed surface of PET, and the mechanism of PEO transport in the nanopores are equally important factors affecting the direction of the macromolecule mass transfer in the nanopores (penetration or release) and PEO content variation as a function of PET tensile strain.

  9. What does Germany expect to gain from hosting the 2006 Football World Cup – Macroeconomic and Regionaleconomic Effects

    OpenAIRE

    Ahlert, Gerd

    2005-01-01

    The paper will present some estimates of the potential macro- and regionaleconomic effects for the German economy from hosting the football world cup 2006. The results have been prepared in the years 2000 and 2001 using the sport-economic simulation model SPORT (Ahlert 2001). The model has a special focus on analyzing sport-economic activities and has been constructed within the framework of a research project financed by the Ministry of the Interior (Meyer & Ahlert, 2000). It is based on a s...

  10. HDAC Inhibitor Panobinostat Engages Host Innate Immune Defenses to Promote the Tumoricidal Effects of Trastuzumab in HER2(+) Tumors.

    Science.gov (United States)

    Medon, Mikolaj; Vidacs, Eva; Vervoort, Stephin J; Li, Jason; Jenkins, Misty R; Ramsbottom, Kelly M; Trapani, Joseph A; Smyth, Mark J; Darcy, Phillip K; Atadja, Peter W; Henderson, Michael A; Johnstone, Ricky W; Haynes, Nicole M

    2017-05-15

    Histone deacetylase inhibitors (HDACi) may engage host immunity as one basis for their antitumor effects. Herein, we demonstrate an application of this concept using the HDACi panobinostat to augment the antitumor efficacy of trastuzumab (anti-HER2) therapy, through both tumor cell autonomous and nonautonomous mechanisms. In HER2(+) tumors that are inherently sensitive to the cytostatic effects of trastuzumab, cotreatment with panobinostat abrogated AKT signaling and triggered tumor regression in mice that lacked innate and/or adaptive immune effector cells. However, the cooperative ability of panobinostat and trastuzumab to harness host anticancer immune defenses was essential for their curative activity in trastuzumab-refractory HER2(+) tumors. In trastuzumab-resistant HER2(+) AU565(pv) xenografts and BT474 tumors expressing constitutively active AKT, panobinostat enhanced the antibody-dependent cell-mediated cytotoxicity function of trastuzumab. IFNγ-mediated, CXCR3-dependent increases in tumor-associated NK cells underpinned the combined curative activity of panobinostat and trastuzumab in these tumors. These data highlight the immune-enhancing effects of panobinostat and provide compelling evidence that this HDACi can license trastuzumab to evoke NK-cell-mediated responses capable of eradicating trastuzumab-refractory HER2(+) tumors. Cancer Res; 77(10); 2594-606. ©2017 AACR. ©2017 American Association for Cancer Research.

  11. Conducting network penetration and espionage in a global environment

    CERN Document Server

    Middleton, Bruce

    2014-01-01

    When it's all said and done, penetration testing remains the most effective way to identify security vulnerabilities in computer networks. Conducting Network Penetration and Espionage in a Global Environment provides detailed guidance on how to perform effective penetration testing of computer networks-using free, open source, and commercially available tools, including Backtrack, Metasploit, Wireshark, Nmap, Netcat, and Nessus. It also considers exploits and other programs using Python, PERL, BASH, PHP, Ruby, and Windows PowerShell.The book taps into Bruce Middleton's decades of experience wi

  12. Market penetration of new energy technologies

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Simulation of depth of penetration during ballistic impact on thick ...

    Indian Academy of Sciences (India)

    dimensional models; ballistic impact; thick target; depth of penetration. 1. Introduction. Ballistic impact is the study which deals with projectile hitting the target and observing its effects in terms of deformation and fragmentation of the target. The need ...

  14. Evidence Report: Risk of Adverse Health Effects Due to Host-Microorganism Interactions

    Science.gov (United States)

    Ott, C. Mark; Oubre, Cherie; Wallace, Sarah; Mehta, Satish; Pierson, Duane

    2016-01-01

    While preventive measures limit the presence of many medically significant microorganisms during spaceflight missions, microbial infection of crewmembers cannot be completely prevented. Spaceflight experiments over the past 50 years have demonstrated a unique microbial response to spaceflight culture, although the mechanisms behind those responses and their operational relevance were unclear. In 2007, the operational importance of these microbial responses was emphasized as the results of an experiment aboard STS-115 demonstrated that the enteric pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) increased in virulence in a murine model of infection. The experiment was reproduced in 2008 aboard STS-123 confirming this finding. In response to these findings, the Institute of Medicine of the National Academies recommended that NASA investigate this risk and its potential impact on the health of the crew during spaceflight. NASA assigned this risk to the Human Research Program. To better understand this risk, evidence has been collected and reported from both spaceflight analog systems and actual spaceflight including Mir, Space Shuttle, and ISS missions. Although the performance of virulence studies during spaceflight are challenging and often impractical, additional information has been and continues to be collected to better understand the risk to crew health. Still, the uncertainty concerning the extent and severity of these alterations in host-microorganism interactions is very large and requires more investigation as the focus of human spaceflight shifts to longer-duration exploration class missions.

  15. Risk of Adverse Health Effects Due to Host-Microorganism Interactions

    Science.gov (United States)

    Ott, C. Mark; Oubre, Cherie; Castro, Sarah; Mehta, Satish; Pierson, Duane

    2015-01-01

    While preventive measures limit the presence of many medically significant microorganisms during spaceflight missions, microbial infection of crewmembers cannot be completely prevented. Spaceflight experiments over the past 50 years have demonstrated a unique microbial response to spaceflight culture, although the mechanisms behind those re