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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Formulation, in vitro release and transdermal diffusion of salicylic acid and topical niacinamide / by Sarita Jacobs

Jacobs, Sarita January 2009 (has links)
Acne affects as many as 80% of young adults and adolescents all over the world. This detrimental condition can be classified into four stages: (a) open comedo (blackhead), (b) closed comedo (whitehead), (c) papule and (d) pustule (Russell, 2000:357-366). There are various factors that can lead to acne outbreaks which include: (a) hormone level changes during the menstrual cycle in women, (b) certain drugs (i.e. lithium), (c) certain cosmetics and (d) environmental conditions such as humidity (University of Maryland, 2009:1). The skin performs a variety of functions which include the two major functions: (a) the containment and (b) the protection of the internal organs of the body. The containment function relates specifically to the ability of the skin to confine the underlying tissues and restrain their movement from place to place. The protective function, on the other hand, relates to the ability of the skin to act as a microbiological barrier to most micro-organisms; a chemical barrier to exogenous chemical compounds; barrier to radiation and electrical shock; and mechanical barrier to impact (Danckwerts, 1991:315). Niacinamide and salicylic acid were chosen in combination, due to the beneficial effects that they have on acne. Niacinamide has an anti-inflammatory action on acne; which reduces redness, dryness and irritation caused by Propioni-bacterium acnes that live in the clogged pores of pimples (Acnetreatmentlab, 2008:1). Salicylic acid is a keratolytic and keratoplastic agent. It is used in combination with other ingredients to enhance the shedding of corneocytes. This causes penetration into the skin to be very difficult (SAMF, 2005:177). The solubility of niacinamide and salicylic acid in PBS (pH 7.4 at 32°C) were 212.95 mg/ml and 4.07 mg/ml, respectively. The log D values of niacinamide and salicylic acid were determined to be -0.32 and 0.33, respectively. According to the solubility of niacinamide and salicylic acid it was expected that both of the active ingredients would permeate through the skin. However, it is expected that niacinamide will depict enhanced permeation with respect to salicylic acid. The results of the log D for both of the active ingredients indicate that there would not be optimal permeation. This study involved the formulation of four different acne preparations (Pheroid™cream, Pheroid™gel, cream and gel), combining niacinamide and salicylic acid. The evaluation of stability parameters for the different formulations indicated that none of the formulations was stable under the different storage conditions determined by the Medicines Control Council. Nevertheless, the cream and gel were the most stable of the four formulations. Visual assessment of the Pheroid™ formulations with the confocal laser scanning microscopy (CLMS) was conducted and inconclusive evidence to whether the active substances were entrapped within the Pheroids™, was obtained. Franz cell diffusion studies indicated that the cream (in the case of niacinamide) and gel (in the case of salicylic acid) depicted the highest average and median flux from hours 6 to 12. Results of the tape stripping studies showed that with the gel formulation, concentrations of 2.060 ug/ml and 44.749 ug/ml niacinamide were obtained in the epidermis and dermis respectively. After the Pheroid™ gel was applied, tape stripping depicted only 1.587 ug/ml niacinamide in the epidermis with respect to 22.764 ug/ml niacinamide in the dermis. The cream formulation, on the other hand, showed niacinamide concentrations of 2.001 ug/ml in the epidermis and 13.363 ug/ml in the dermis, whereas with the Pheroid™ cream formulation, concentrations of 1.097 ug/ml and 18.061 ug/ml were obtained in the epidermis and dermis respectively. Tape stripping results depicted that with the gel formulation, concentrations of 2.113 ug/ml and 49.519 ug/ml salicylic acid were obtained in the epidermis and dermis respectively, whereas the Pheroid™ gel formulation showed salicylic acid, concentrations of 1.114 ug/ml in the epidermis and 95.360 ug/ml in the dermis. The cream formulation, however, depicted salicylic acid concentrations of 0.758 ug/ml in the epidermis and 44.729 ug/ml in the dermis. Lastly, after the Pheroid™ cream was applied, salicylic acid concentrations of 0.411 ug/ml and 48.424 ug/ml in the epidermis and dermis respectively, were measured. It could, therefore, be concluded that both niacinamide and salicylic acid tend to concentrate more in the dermis, irrespective of the formulation. This may be an advantage since acne is usually targeted in the dermis and epidermis. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.
22

Nešiklio įtakos salicilo rūgšties atpalaidavimui iš pusiau kietų sistemų tyrimas in vitro / Evaluation of vihicle's effect on salicylic acid release in vitro from semi-solid preparations

Nevecka, Andrius 30 June 2014 (has links)
Darbo tikslas: įvertinti gamybinėse vaistinėse pagamintų tepalų su salicilo rūgštimi kokybę nustatant veikliosios medžiagos atpalaidavimą in vitro ir pasiūlyti alternatyvios sudėties ir gamybos technologijos puskietes sistemas, pasižyminčias ne mažesniu salicilo rūgšties atpalaidavimu in vitro. Darbo uždaviniai: 1. Parinkti ir pritaikyti salicilo rūgšties kiekybinės analizės metodiką; 2. Parinkti tinkamas sąlygas salicilo rūgšties atpalaidavimo iš tepalų tyrimams in vitro; 3. Ištirti salicilo rūgšties atpalaidavimą in vitro iš Lietuvos vaistinėse pagamintų tepalų; 4. Sumodeliuoti alternatyvios sudėties puskietes sistemas su salicilo rūgštimi, jas pagaminti ir įvertinti jų kokybę; 5. Ištirti salicilo rūgšties atpalaidavimą in vitro iš sumodeliuotų puskiečių sistemų bei palyginti gautus atpalaidavimo rezultatus su vaistinėse pagamintų tepalų atpalaidavimo rezultatais. Metodai: Salicilo rūgšties išsiskyrimas iš puskiečių sistemų tirtas naudojant modifikuotas Franz tipo celes. Salicilo rūgštis kiekybiškai nustatyta spektrofotometrijos metodu naudojant spektrofotometrą Agilent 8453, bangos ilgis 296 nm. Kalibracinio grafiko koncentracija ribose 0,005-0,03 mg/ml. Tepalų kokybė nustatyta vertinant tepalo pH ir dinaminę klampą. Rezultatai: po 4 h 5 % salicilo rūgšties tepalai atpalaidavo salicilo rūgšties: LSMU vaistinės- 3,36±0,16 %, “Ąžuolyno” vaistinės- 2,54±0,12 %, UAB “VJV“- 2,71±0,20 %, eksperimentinis 1,89±0,14 %, tepalai, pagaminti sudėtines medžiagas sumaišius grūstuvėje... [toliau žr. visą tekstą] / Objective of work: to evaluate quality of salicylic acid ointments manufactured by pharmacies by assessing release of salicylic acid in vitro and suggest alternative composition and technique semi- solid preparation, characterized by the same or better release of salicylic acid. Main tasks: 1. To select and adapt a suitable method for quantity analysis for salicylic acid; 2. To select appropriate conditions for salicylic acid release in vitro from semi- solid preparation; 3. To research release of salicylic acid in vitro from semi-solid preparations made by Lithuanian pharmacies; 4. To formulate semi- solid preparations containing salicylic acid and evaluate quality; 5. To research release of salicylic acid in vitro from formulated semi- solid preparations and compare release results with release results of semi- solid preparations made by Lithuanian pharmacies. Methods: release of salicylic acid from semi- solid preparations executed by using modificated vertical diffusion Franz cells. The quantity analysis executed by using spectrophotometric methods. UV- Vis spectrophotometer Agilent 8453, wavelength 296 nm, calibration curve within 0,005- 0,03 mg/ml. Ointments quality evaluated by pH and dynamic viscosity. Results: after 4 h 5 % salicylic acid ointments released salicylic acid: LSMU pharmacy‘s ointment- 3,36 %, “Ąžuolyno” pharmacy‘s ointment- 2,54 %, UAB “VJV“ ointment- 2,71 %, experimental ointment- 1,89 %; ointments made by mixing in mortar with glycerol- 2,27 %... [to full text]
23

Amino acid derivatives of aminosalicylic acids

Hull, Robert Lee, January 1952 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1952. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 52-54).
24

The hydrogen bond formation of various alcohols with salicylic acid, catechol and hydroquinone in nonaqueous solution

Chulkaratana, Sunis, January 1961 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1961. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 27).
25

Hydrogen peroxide assisted heterogeneous photocatalytic oxidation of salicylic acid with novel oscillatory flow photocatalytic reactor /

Lee, Michael Ho Kei. January 2005 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 92-94). Also available in electronic version.
26

Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis

Naidoo, Ronishree 10 August 2012 (has links)
Eucalyptus species form an integral part of the South African forestry industry and their uses extend from paper and pulp production to the synthesis of essential oils which are used in various cosmetic products. Throughout their lifetime these hosts are naturally challenged with various pests and pathogens, most of which cause devastating diseases. An approach to curb the spread of pathogens is to enhance the defence response of the host. Most of the information pertaining to defence against pathogens stems from studies conducted in model organisms such as Arabidopsis, however such information is scarce in woody species such as Eucalyptus. It is understood, from model systems, that once the pathogen is perceived by the host, a cascade of defences are initiated such as the activation of salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signalling pathways. These pathways in turn activate the expression of genes involved in limiting the spread of the pathogen such as pathogenesis-related (PR) proteins. Certain PR genes have also been shown to be markers of the induction of a specific pathway e.g. PR2 is a marker for the SA pathway. This study aimed to elucidate marker genes specific to the SA (PR1, PR2 and PR5) and JA (PR3, PR4 and LOX) signalling pathways in Eucalyptus grandis using the genome sequence, bioinformatics tools and sequence information from other plant species. A co-phylogenetic approach using neighbour joining analysis and maximum likelihood was used to identify and add confidence in the selection of putative orthologs. Following the selection of orthologous markers, the expression profile of these candidate genes was assessed using Reverse transcriptase quantitative PCR (RT-qPCR). Transcript profiling was conducted under mock induction of the signalling pathways as well as under pathogen stress. For the mock induction of the pathways, the expression profiles of the putative marker genes were investigated under various concentrations of the inducer and at various time points. In the interaction with Chrysoporthe austroafricana it was observed that the SA signalling pathway could have a role in facilitating resistance due to the expression profile observed for EgrPR2. In the tolerant genotype (TAG5) this gene was induced at an earlier time point as opposed to the susceptible genotype (ZG14). These putative markers could provide a diagnostic tool for the screening of pathogen challenged eucalypts to determine which signalling pathway(s) are activated against various pathogens. In addition, this research adds to our knowledge of defence responses in E. grandis by elucidating genes that can be used as targets for improving resistance. Additionally this study provides a stepping stone for understanding mechanisms to curb future tree diseases. / Dissertation (MSc)--University of Pretoria, 2014. / Genetics / Unrestricted
27

Investigating the Role of the Arabidopsis Homologue of the Human G3BP in RNA Metabolism, Cellular Stress Responses and Innate Immunity

Abulfaraj, Aala A. 04 1900 (has links)
Mitogen-activated protein kinases (MAPKs) belong to the most conserved signaling pathways and are found in all eukaryotes, including humans where they play important roles in various diseases and cancer. Stimulation of this signal transduction pathway by microbe-associated molecular patterns (MAMP) results in a multitude of events to regulate innate immune responses in Arabidopsis thaliana stimulating large-scale changes in gene expression. Starting from a phosphoproteomic screen in Arabidopsis thaliana wild type and mpk3, mpk4 and mpk6 mutants following microbe-associated molecular pattern (MAMP) treatment, several novel chromatin-associated proteins were identified that are differentially phosphorylated by stress-induced protein kinases. Arabidopsis Ras GTPase-activating protein SH3-domain-binding protein (AtG3BP-1) is a downstream putative substrate of the MAMP-stimulated MAPK pathway that is phosphorylated by MPK3, 4 and 6 in in vitro kinase assays. AtG3BP1 belongs to a highly conserved family of RNA-binding proteins in eukaryotes that link kinase receptormediated signaling to RNA metabolism. Here, we report the characterization of the Arabidopsis homolog of human G3BP1 in plant innate immunity. AtG3BP1 negatively regulates plant immunity and defense immune responses. Atg3bp1 mutant lines show constitutive stomata closure, expression of a number of key defense marker genes, and accumulate salicylic acid but not jasmonic acid. Furthermore, Atg3bp1 plants exhibit enhanced resistance to the biotrophic pathogen Pseudomonas syringae pv. tomato. Pathogen resistance was mediated by stomatal and apoplastic immunity in Atg3bp1. More generally, our data reinforce that AtG3BP1 is a key mediator of plant defense responses and transient expression of AtG3BP1 delivered striking disease resistance in the absence of yield penalty, highlighting a potential application of this gene in crop protection.
28

The Milk Withholding Time of Salicylic Acid for Treatment of Digital Dermatitis in Dairy Cattle

Wirt, Kelsey Marie January 2020 (has links)
Digital dermatitis is a top cause of lameness in dairy cattle that results in ulcerative lesions on the feet. Topical salicylic acid has been shown to provide similar efficacy to the antibiotic drugs used previously, but there is no milk withholding time established in the United States. The objective of this study was to provide data in order to establish this withholding period. A secondary objective was to evaluate outcomes among treatments. Treatment groups were topical applications of the following drugs: salicylic acid paste, salicylic acid powder, and tetracycline. The lesions were scored at day 0, day 7, and day 28 post-treatment. Milk samples were collected the day before treatment, 4 hours, 8 hours, 24 hours, 36 hours, and 48 hours post-treatment. Results indicated that most cows did not show detectable levels of salicylic acid after 24 hours.
29

The effect of lipo-chitooligosaccharide from Bradyrhizobium japonicum, on soybean salicylic acid, pathogenesis-related protein activity and gene expression /

Lindsay, John Keldeagh. January 2007 (has links)
No description available.
30

Use of Transposon Screening for Salicylic Acid-Assisted Desiccation Killing in Salmonella

Elliott, Shannon D 01 August 2023 (has links) (PDF)
Salmonella enterica serovar Typhimurium is one of the most prevalent food-borne pathogens, affecting millions around the world every year, making it a threat to global health. Salmonella possesses the ability to survive the normally lethal condition of desiccation, however, discovery of the genes and mechanisms behind this phenomenon are still ongoing. Using a transposon mutagenesis approach to construct a broad transposon library, this study aimed to uncover genes that may be contributing to changes in Salmonella’s survivability under desiccation, particularly when exposed to the antimicrobial molecule salicylic acid. Building on previous findings showing salicylic acid can alter cell viability through differential gene regulation, transposon mutants were exposed to salicylic acid and subsequently desiccated to screen for mutants that displayed an alteration in survival phenotypes. This work identified a transposon mutant with an interruption of the porin-coding gene ompC that displayed an augmented survivability phenotype under these conditions, leading to further exploration into the origin of this phenomenon.

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