The fabrication and characterization of stable core-shell superparamagnetic nanocomposites for potential application in drug delivery

Two systems of core-shell superparamagnetic nanoparticles in the size range 45 to 80 nm have been fabricated by the coating of bare magnetite particles with either mesoporous silica or liposomes and the loading/release of the anti-cancer drug Mitomycin C (MMC) from their surfaces has been investigated. The magnetic cores of size ~ 10 nm were produced by a co-precipitation method in aqueous solution, with the silica coating containing an unstructured network of pores of size around 6 nm carried out using a surfactant-templating approach and the liposome coating achieved by an evaporation-immersion technique of the particles in a lipid solution. Stability measurements using a scanning column magnetometry technique indicated that the lipid-coating of the particles halts the sedimentation otherwise apparent in < 1 hour for the bare magnetite to produce an ultra-stable system and thereby overcome one of the main barriers to potential in-vivo applications. Whilst an increase in stability was also observed in the silica-coated system, it was still unstable over a few hours and will require further investigation. Magnetization curves of the coated systems were indicative of superparamagnetic behavior whilst the in vitro loading and release of MMC resulted in two distinctly different outcomes for the two systems: (i) the silica-coated particles saturated in < 4 hours to a loading of around 7 µg/mg of material, releasing about 6 % at a near constant rate over 48 hours whilst (ii) the lipid-coated particles saturated to around only 4 µg/mg over the same time period but with a subsequent rapid release rate over the first 3 hours to 27 % then rising near-linearly to a value of about 45 % at the 48 hour mark. This gives scope for systems’ to be tuned to the appropriate rate and load delivery as required by clinical need with further investigations underway

Low complexity channel estimation for low-mobility LTE using 4×4 MIMO

Multiple-input multiple-output (MIMO) is a mandatory feature of the Third Generation Partnership Project (3GPP) Long Term Evolution. This work investigates the performance of a low complexity channel estimator for LTE terminals with an emphasis on the 4 × 4 multiple antenna scheme. The presented work extends a promising low-complexity 2 × 2 MIMO channel estimator to the 4 × 4 MIMO case and evaluates its performance at different terminal speeds. The evaluation is done in terms of simulated error performance for coded LTE. We show that the presented channel estimator can be used without a significant performance loss up to about 15-20 km/h, where the approximations done to achieve low complexity start to have a significant impact on the performance

Addition As A Translation Adjustment Technique In The Selected English Translations Of Implicit Direct Object Ellipsis In The Holy Qur’ān

Al-Quran merupakan sebuah daripada buku yang sangat menarik dan kitab bacaan agama yang meluas. Kitab ini yang berunsurkan agama Islam dan budaya Arab, sesetengah konsep dan maknanya mungkin tidak begitu telus kepada penutur bahasa lain, kerana ia berelipsis. The Holy Qur’ān is one of the most fascinating and widely-read religious and divine books. Belonging to Islamic and Arabic cultures, some concepts and meanings of the Qur’ān might not be so transparent to the speakers of other languages, as they are ellipted

Einsatz von equinem Choriongonadotropin (eCG) beim Rind post partum zur Förderung der Ovaraktivität

Ziel des Dissertationsvorhabens ist es, die Hypothese zu überprüfen, dass durch die Gabe von equinem Choriongonadotropin (eCG) am 6. Tag post partum die Ovaraktivität bei der Milchkuh positiv beeinflusst werden kann. Die Untersuchung wurden an 63 Kühen unterschiedlicher Rassen mit ungestörtem und gestörtem Puerperium bis zum 10. Tag post partum durchgeführt. Es gab drei Gruppen von Tieren: Kontroll-Gruppe (keine Behandlung, n = 13), eine Gruppe mit Kühen, die an Tag 6 post partum eCG (480 I. E.) erhielten (n = 25), eine Gruppe mit Kühen, die an Tag 6 post partum GnRH (21µg) (n = 25) appliziert bekamen. Am 6. Tag und 10. Tag nach der Geburt wurde von den Kühen der beiden Behandlungsgruppen Blut aus der Schwanzvene entnommen. Am Tag 10 nach der Geburt wurde bei allen Kühen (Behandlungsgruppen und Kontrollgruppen) Blut aus der Schwanzvene entnommen. Es wurde überprüft, ob die Estradiol-Konzentrationen der Kühe in den Behandlungsgruppen von Tag 6 zu Tag 10 ansteigt und ob am Tag 10 zwischen den Behandlungsgruppen und der Kontrollgruppe Unterschiede vorliegen. Weiterhin wurde überprüft, ob ein Zusammenhang zwischen der Estrogenkonzentration an Tag 10 und der GLDH-Aktivität vorliegt. Folgende Ergebnisse konnten erzielt werden: - In keiner Behandlungsgruppe konnte ein signifikanter Estrogenanstieg ermittelt werden. - Unterschiede zwischen den drei Gruppen lagen nicht vor. Es kann geschlussfolgert werden, dass die Gabe von eCG am 6. Tag post partum nicht zu einer Anregung der Ovarfunktion führt.Objective of this study was to examine the hypothesis if a treatment with equine choriongonadotropin (eCG) during the first 6 days after calving may influence the ovarian activity. The study was performed in 63 post parturient cows of different breeds until day 10 of puerperium. Animals were divided in 3 groups, a control group (no treatment = 13), a group of cows receiving eCG (480 I. E.) (n = 25) and one group of cows receiving GnRH (21 µg) (n = 25) at day 6 of puerperium respectively. At day 6 and 10 after calving blood was taken out of the tail veins of both treatment groups. It was examined if a rise of the estrogen concentration could be detected between day 6 and 10 in the treated cows and the result was compared with the control group. Additionally a correlation between the GLDH-activity and estradiol concentrations was determined in all cows. Following results were determined: -The estradiol concentrations were compared between groups at day 10 of puerperium, but no differences could be shown. -no differences in all three groups could be detected. It may be concluded that an eCG treatment at day 6 post partum does not stimulate ovarian activity

Investigation of the role of exogenous use of sucrose as an osmoprotectant in increasing Azolla filiculoides resistance to air high temperature and salt stress

Influence of 2.75 to 11 moles sucrose as an exogenous osmoprotectant on salt stressed (7.8-9.1 and 18.2 ms/cm) and temperature stressed (42.36°C) Azolla (A. filiculoides Lam.) was studied. Results showed that enriching salt stressed (9.1 ms/cm) Azolla by 5.5 moles sucrose significantly increased survival percent (S%) and freshness percent (F%), in comparison with control treatment in which no sucrose was used. Enriching Azolla media by 2.75, 5.5 and 8.25 moles sucrose in optimum growth condition (24.18C and 0.65 mS/cm), had no significant effects on growth doubling time (D.T), S% and F% in comparison with control. Enriching Azolla media by 11 moles sucrose in optimum growth condition decreased significantly the S% and F%, in comparison with control plots. Enriching Azolla media by 5.5 moles sucrose, in all salinity levels (0.65, 7.8, 9.1 and 18.25 ms/cm), and air temperatures (24.18 and 42.36C), non-increased S% and F% but not significantly and decreased D.T.A positive correlation was observed between high air temperature and medium salinity in Azolla growth

Study of porous magnetic nanocomposites for bio-catalysis and drug delivery

Despite advances in diagnostic procedures and treatments, the overall survival rate from cancer has not improved substantially over the past 30 years. One promising development is the encapsulation of toxic cancer chemotherapeutic reagents within biocompatible nanocomposite materials. The targeted stimuli triggered drug release restrict the toxic drugs to the tumour site, thereby reducing the effects of “free drug” on healthy tissues. One of the most versatile and safe materials used in medicine are iron oxide nanoparticles. This project describes the development of several formulations based on magnetite nanoparticles for drug delivery applications. Utilising magnetic nanoparticles in drug delivery systems allowed for the synergistic effects of hyperthermia and heat triggered drug released. The drug delivery systems developed in this project include magnetoliposomes, magnetic micelles, mesoporous silica-magnetite core-shell nanoparticles, liposome capped mesoporous silica-magnetite core-shell nanoparticles (protocells) and polymer capped mesoporous silica-magnetite core-shell nanoparticles. The drug loading and release profiles of the developed nanomaterials were assessed using two different anticancer drugs; Mitomycin C (MMC) and Doxorubicin (DOX). The drug loading content and drug loading efficiency for different nanocomposites ranged from 0.48 to 10.30% and 16.16 to 85.85%, respectively. Drug release profiles were studied in vitro at 37°C at pH 5.5 and pH 7.4 and at hyperthermia elevated temperature of 43°C to evaluate the effects of pH and temperature on the release profiles. An AC magnetic field with frequency of 406 kHz and variable field of up to 200 G was used to induce magnetic heating and keep the temperature within hyperthermia treatment range. Compared to uncapped mesoporous silica nanoparticles capping the mesopores of the silica nanoparticles with liposome or polymer reduced the drug release by 52.7% and 41.5%, respectively. The efficacy of doxorubicin-containing nanoparticles were evaluated in vitro against breast cancer and glioblastoma cell lines where different formulations demonstrated comparable or increased cytotoxicity compared to free drug. The cells treated with DOX loaded nanoparticles and hyperthermia demonstrated up to 89% lower viability compared to cells treated with free DOX. Silica coated magnetic nanoparticles were also used as enzymes (Pseudomonas Fluorescens Lipase (PFL) and Candida Rugosa Lipase (CRL)) supports in catalysis reactions. The enzymes were immobilised onto nanoparticles through physical adsorption and chemical bonding. The immobilised lipases were used in hydrolysis of pNPP and hydrolysis of cis-3,5-diacetoxy-1-cyclopentene to investigate the catalytic activity of the immobilized enzymes compared to free enzymes. The results indicated that free lipases provided slightly higher conversion than immobilised lipases in the first cycle however, the immobilised lipases were easily recycled and reused in sequential cycles which provides higher total yield per mg of lipase. The chemically immobilised lipase exhibited good reusability without loss of its activity in sequential cycles, however the physically adsorbed lipase showed reduced activity which could be explained by loss of enzyme during recycling between successive reactions. The CRL lipase activity were further assessed in the presence of an AC field where the results showed that exposure to the AC magnetic field resulted in increased lipase activity. The effect of reaction temperature on immobilised lipase activity were studied by performing the hydrolysis of cis-3,5-diacetoxy-1-cyclopentene at two temperatures of 25°C and 37°C where it was observed that both lipases exhibited higher activity at higher temperature which could be due to the fact that for PFL and CRL the optimum temperature is close to 37°C

Influencia de diferentes regímenes de riego y tiempo de siembra en la calidad y cantidad del cáliz, el contenido de aceite de las semillas y la eficiencia del uso del agua de la roselle (Hibiscus sabdariffa L.)

This study was carried out to examine the physiological traits, quality of calyx extract and seed oil content of roselle (Hibiscus sabdariffa L.) as affected by irrigation regimes and planting dates. The growth period from seed sowing to calyx harvesting was shortened as planting time was delayed. Stem diameter and plant height were decreased by drought stress or late planting, but calyx yield, total phenolic content, total anthocyanin content, vitamin C, and calyx water use efficiency increased under mild drought condition. In addition, antioxidant activity and calyx water use efficiency were significantly increased by late planting. It was suggested that an increase in calyx harvest index in delay in planting would be due to better photosynthesis activity and higher assimilate use efficiency because of the increase in sink capacity. Seed oil content decreased considerably due to drought stress and delay in planting date. These findings suggest that mild drought stress improves the quality and quantity of calyx and water use efficiency.Este estudio se llevó a cabo para examinar los rasgos fisiológicos, la calidad del extracto de cáliz y el contenido de aceite de semillas de roselle (Hibiscus sabdariffa&nbsp;L.) afectado por regímenes de riego y fecha de siembra. El período de crecimiento desde la siembra de la semilla hasta la cosecha del cáliz se acortó debido a que se retrasó el tiempo de siembra. El diámetro del tallo y la altura de la planta disminuyeron por el estrés por sequía o la siembra tardía, pero el rendimiento del cáliz, el contenido fenólico total, el contenido total de antocianinas, la vitamina C y la eficiencia del uso del agua del cáliz aumentaron en condiciones de sequía leve. Además, la actividad antioxidante y la eficiencia del uso del agua del cáliz aumentaron significativamente en la siembra tardía. Se sugirió que el aumento del índice de cosecha del cáliz en la demora en la siembra se debería a una mejor actividad de fotosíntesis y una mayor eficiencia en el uso de asimilación debido al aumento de la capacidad de hundimiento. El contenido de aceite de las semillas disminuyó considerablemente debido al estrés por sequía y al retraso en la fecha de siembra. Estos hallazgos sugieren que el estrés por sequía leve mejora la calidad y cantidad del cáliz y la eficiencia del uso del agua

Drug-loaded liposome-capped mesoporous core-shell magnetic nanoparticles for cellular toxicity study

Liposome-capped core-shell mesoporous silica-coated superparamagnetic iron oxide nanoparticles called 'magnetic protocells' were prepared as novel nanocomposites and used for loading anticancer drug doxorubicin (DOX) for cellular toxicity study. Cytotoxicity of the magnetic protocells with or without DOX was tested in vitro on commercial MCF7 and U87 cell lines under alternating magnetic field MCF7 cell line treated with the DOX-loaded nanoparticles under alternating magnetic field exhibited nearly 20% lower survival rate..

Broadband optical measurement of AC magnetic susceptibility of magnetite nanoparticles

This is the author accepted manuscript. The final version is available from AIP Publishing via the DOI in this recordCharacterization of magnetic nanoparticles in solution is challenging due to the interplay between magnetic relaxation and agglomeration. The AC magnetic susceptibility of magnetite nanoparticles in water has been studied using magneto-optical methods in the frequency range of 10 Hz–250 kHz. The Faraday effect is detected simultaneously with changes in the fluid configuration. It is shown that the relative sensitivity to the magnetic and structural response can be adjusted by varying the wavelength, paving the way toward spatially resolved studies at the micro-scaleEngineering and Physical Sciences Research Council (EPSRC

Association between ethical leadership, ethical climate and organizational citizenship behavior from nurses' perspective: a descriptive correlational study

Background:Ethical leadership plays an important role in improving the organizational climate and may be have an effect on citizenship behavior. Despite the growing emphasis on ethics in organizations, little attention to has been given this issue. The purpose of this study was to identify ethical leadership, an ethical climate, and their relationship with organizational citizenship behavior from nurses' perspective. Methods:In this descriptive correlational study, 250 nurses in twelve teaching hospitals in Tehran were selected by multistage sampling during 2016-2017. The data were collected using Ethical Leadership Questionnaire, Hospital Ethical Climate Survey, and Organizational Citizenship Behavior Scale. Results:The findings showed a significant correlation between ethical leadership in managers, organizational citizenship behavior (P = 0.04, r = 0.09) and an ethical climate (P < 0.001, r = 0.65). There was a significant correlation between an ethical climate and nurses' organizational citizenship behavior (P < 0.001, r = 0.61). The regression analysis showed that ethical leadership and an ethical climate is a predictor of organizational citizenship behavior and confirms the relationship between the variables. Conclusion:Applying an ethical leadership style and creating the necessary conditions for a proper ethical climate in hospitals lead to increased organizational citizenship behavior by staff. To achieve organizational goals, nurse managers can use these concepts to enhance nurses' satisfaction and improve their performance