Genetic computation of geodesics on three-dimensional curved surfaces

Most classical approaches to the determination of geodesics (such as the calculus of variations) are difficult to apply except for simple surfaces. Genetic algorithms are therefore used to provide a general methodology for the computation of geodesics.published_or_final_versio

Oncoproteomic profiling with antibody microarrays

The incidence of cancer and its associated mortality are increasing globally, indicating an urgent need to develop even more effective and sensitive sets of biomarkers that could help in early diagnosis and consequent intervention. Given that many cellular processes are carried out by proteins, cancer research has recently shifted toward an exploration of the full proteome for such discovery. Among the advanced methodologies that are being developed for analyzing the proteome, antibody microarrays have become a prominent tool for gathering the information required for a better understanding of disease biology, early detection, discrimination of tumors and monitoring of disease progression. Here, we review the technical aspects and challenges in the development and use of antibody microarray assays and examine recently reported applications in oncoproteomics

Production of functional protein hydrolysates from Egyptian breeds of soybean and lupin seeds

Enzymatic hydrolysis is an agro-processing aid that can be utilized in order to improve nutritional quality of protein extracts from many sources. In this study, protein extracts from ungerminated and/or germinated local Egyptian soybean and lupin flours were hydrolyzed using the enzyme papain. The hydrolysis processes were carried out for 2 h and aliquots were withdrawn at different time intervals. We have analysed the protein hydrolysate after 30 min hydrolysis as an example of a partially hydrolyzed protein, and after 120 min as an example of greatly hydrolyzed protein. The hydrolysate (2 h treatment at 80°C and pH 7.4) from both soybean and lupin flour contained significantly decreased trypsin inhibitor activity and urease activity, and a reduced phytate content, which improved the overall protein quality. Hydrolysis caused almost complete inactivation of urease in all soybean and lupin samples regardless if the seeds were germinated or not. High protein content, nitrogen solubility and invitro protein digestibility was shown after hydrolysis. Total protein content (in g/100 g extract) increased in hydrolyzed samples from 48.1 to 51-60 for soybean (dependent on pre-treatment) and from36.8 to 39.9-48.6 for lupin. Total essential amino acid content was also increased in papain hydrolyzed samples, compared to that in raw and germinated legumes. More specifically, the amount of lysine,sulphur amino acids, histidine, and to a certain extent isoleucine and threonine increased in samples from both legume species. All soybean samples exhibited antioxidant activity while in lupin samples,only those subjected to hydrolysis showed activity. Generally, it was clearly observed that the longer the duration of enzymatic hydrolysis (within the time frame of the experiment), the higher the improvement of the nutritional qualit

Iterative learning control of multivariable plants

In recent years, many researchers have proposed different iterative learningcontrollers, which unfortunately mostly require that the plants under control beregular. Therefore, in order to remove this limitation, various analogue and digitaliterative learning controllers are proposed in this thesis.Indeed, it is shown that analogue iterative learning controllers can be designed forplants with any order of irregularity using initial state shifting or initial impulsiveaction. However, such analogue controllers have to be digitalised for purpose ofimplementation. In addition, in the synthesis of their control laws, such controllersrequire some knowledge of the plants' Markov parameters. Ilerefore, new digitaliterative learning controllers are proposed. Such digital controllers circumvent theneed for detailed mathematical models of the plants in any form. Indeed, theproposed digital iterative learning controllers rely on input/output data in thesynthesis of their control laws. It is shown that digital iterative learning controllerscan be readily designed for multivariable plants of any order or irregularity using onlysuch input/output data in the form of step-responsem atrices.The learning rates achievable in both the analogue and digital iterative learningcontrol of linear multivariable plants are investigated. It is shown that the irregularityand stability characteristics of the plants under control impose severe constrains on theachievable learning rates. Indeed, it is shown that the learning parameter in the caseof digital iterative learning controllers increases as the order of plant irregularityincreases. This increase in the learning parameter affects the learning performanceand the speed of convergence adversely. This discovery led to the introduction ofcompensators in the design of digital iterative learning controllers for irregular plants which help to improve the learning performance and convergence by reducing theeffective learning parameter. Since such digital iterative learning controllers use stepresponsematrices in the synthesis of their control laws and since the step-responsecharacteristics can be identified in real time, it is shown in this thesis that iterativelearning controllers can readily be rendered adaptive in case plant dynamics areinitially unknown or time-varying.In order to demonstrate the applicability of these results to the control of roboticmanipulators, both analogue and digital iterative learning controllers are designed fora two-link manipulator in both joint and task spaces. Finally, digital iterativelearning controllers are designed and practically implemented in the real-timepositional control of a dc servo actuator

Streptomyces noboritoensis isolated from rhizosphere soil and its use in controlling banana-tissue culture contaminants

In this study, the role of Streptomyces noboritoensis (14) isolated from the rhizosphere of banana plant and having antagonistic activity against the bacterial- and fungal-tissue culture contaminants was determined in vitro. Results show that the filtrate was more effective against the fungal-tissue culture contaminants than the bacterial-tissue culture contaminants. This was indicated when jars were fungifree and bacteria-free after one month and 21 days from incubation, respectively. Results of in vitro application show that the filtrate of S. noboritoensis (14) as a bio-control agent could be used for controlling the contaminants in banana. Data showed that treatment F (sterilized shoots treated with Streptomyces filtrate and cultivated on Streptomyces-inoculated medium) was the most effective followed by treatment E (sterilized shoots untreated with Streptomyces filtrate and cultivated on Streptomyces-inoculated medium). Therefore, the study suggests conducting further studies towards the use of streptomycetes in the biological control in a large scale production.Keywords: Streptomyces, tissue culture contaminants, antagonistic activities, bio-controlAfrican Journal of Biotechnology Vol. 12(20), pp. 2908-291

Evaluating the sterility of orthodontic materials as received from the manufacturer and that exposed to clinic environment - in vitro study

Introduction: Sterilization in orthodontics has been discussed and stressed over times in the dental literature. Sterility of orthodontic materials should be of prime interest to the orthodontist as a health care professional and he should take appropriate measures to prevent the risk of cross infection. Aim: To evaluate the sterility of orthodontic materials as received from the manufacturer and that exposed to clinic environment for 6 months. Materials and methods: The sterility of orthodontic materials "as received" from the manufacturer and "clinically exposed" (unused materials stored in the clinic environment for a period of 6 months) was microbiologically evaluated (universal & conventional PCR).The materials which were included in this study were the sealed and unsealed orthodontic archwires, molar bands, elastomeric module, stainless steel bracket, coil spring and tungsten carbide burs of various brands (American Orthodontics, 3M Unitek, Ormco, Orthosystems, G&H, Modern Orthodontics, SS white etc). Results: After universal and conventional PCR, the detection of micro-organisms in all materials was significantly higher in the clinically exposed samples compared to as received samples from manufacturers (p<0.001). The detection of micro-organisms in all orthodontic wires is significantly higher in the unsealed samples compared to sealed samples (p<0.001). In universal PCR, the detection of microorganisms in all materials (Coil spring, E-chain, Elastomeric, Molar brands, Tungsten carbide) except for SS brackets is significantly higher in both as received and clinically exposed samples. Conclusion: After universal and conventional PCR, we conclude that bacteria were present on almost all orthodontic materials "as received from the manufacturers" and that exposed to a clinical environment. Therefore all materials should be sterilized before use in patients

Association between vitamin D receptor gene polymorphisms and chronic periodontitis among Libyans

Background: Chronic periodontitis (CP) is a common oral disease characterized by inflammation in the supporting tissue of the teeth ‘the periodontium’, periodontal attachment loss, and alveolar bone loss. The disease has a microbial etiology; however, recent findings suggest that the genetic factors, such as vitamin D receptor (VDR) gene polymorphisms, have also been included.Aim: Investigation of the relationship between VDR gene polymorphisms and CP among Libyans.Materials and methods: In this study, we examined 196 unrelated Libyans between the ages of 25 and 65 years, including 99 patients and 97 controls. An oral examination based on Ramfjord Index was performed at different dental clinics in Tripoli and information were collected using a self-reported questionnaire. DNA was extracted from buccal swabs; the VDR ApaI, BsmI, and FokI polymorphisms were genotyped using polymerase chain reaction and were sequenced using Sanger Method.Results: A significant difference in the newly detected ApaI SNP C/T rs#731236 was found (p0.022), whereas no significant differences were found in ApaI SNP G/T rs#7975232, BsmI SNPA/G rs#1544410, and FokI SNP A/G rs#2228570 between patients and controls (p0.939, 0.466, 0.239), respectively.Conclusion: VDR ApaI SNP C/T rs#731236 may be related to the risk of CP in the Libyan population.Keywords: chronic periodontitis; vitamin D receptor; gene; polymorphisms; variations; SN

MTN-001: Randomized Pharmacokinetic Cross-Over Study Comparing Tenofovir Vaginal Gel and Oral Tablets in Vaginal Tissue and Other Compartments

Background: Oral and vaginal preparations of tenofovir as pre-exposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) infection have demonstrated variable efficacy in men and women prompting assessment of variation in drug concentration as an explanation. Knowledge of tenofovir concentration and its active form, tenofovir diphosphate, at the putative vaginal and rectal site of action and its relationship to concentrations at multiple other anatomic locations may provide key information for both interpreting PrEP study outcomes and planning future PrEP drug development. Objective: MTN-001 was designed to directly compare oral to vaginal steady-state tenofovir pharmacokinetics in blood, vaginal tissue, and vaginal and rectal fluid in a paired cross-over design. Methods and Findings: We enrolled 144 HIV-uninfected women at 4 US and 3 African clinical research sites in an open label, 3-period crossover study of three different daily tenofovir regimens, each for 6 weeks (oral 300 mg tenofovir disoproxil fumarate, vaginal 1% tenofovir gel [40 mg], or both). Serum concentrations after vaginal dosing were 56-fold lower than after oral dosing (p<0.001). Vaginal tissue tenofovir diphosphate was quantifiable in ≥90% of women with vaginal dosing and only 19% of women with oral dosing. Vaginal tissue tenofovir diphosphate was ≥130-fold higher with vaginal compared to oral dosing (p<0.001). Rectal fluid tenofovir concentrations in vaginal dosing periods were higher than concentrations measured in the oral only dosing period (p<0.03). Conclusions: Compared to oral dosing, vaginal dosing achieved much lower serum concentrations and much higher vaginal tissue concentrations. Even allowing for 100-fold concentration differences due to poor adherence or less frequent prescribed dosing, vaginal dosing of tenofovir should provide higher active site concentrations and theoretically greater PrEP efficacy than oral dosing; randomized topical dosing PrEP trials to the contrary indicates that factors beyond tenofovir's antiviral effect substantially influence PrEP efficacy. Trial Registration: ClinicalTrials.gov NCT00592124

Size-Tailored Physicochemical Properties of Monodisperse Polystyrene Nanoparticles and the Nanocomposites Made Thereof

The latex monodisperse polystyrene (PS) colloids are important for different advanced applications (e.g. in coating, biotechnology etc.). However, the size dependency of their structural properties that impacts the characteristics of the nanocomposites composed thereof is largely unknown. Here, monodisperse PS nanoparticles (MPNPs) are synthesized via emulsion polymerization in five sizes (50, 150, 300, 350, and 450 nm). The size of the PS MPNPs is tailored by controlling the reaction time, temperature, and amount of surfactant and initiator. The correlation between the particle size and structural properties of the PS MPNPs is established by different thermomechanical and optical characterizations. The smaller particles (50 and 150 nm) show a lower glass transition (Tg) and thermal decomposition temperature and a lower Raman peak intensity. Yet, they trigger a higher IR absorption, thanks to a larger surface area. When incorporated in a polyvinyl alcohol (PVA) matrix, the smaller particles impart the resulting nanocomposite a higher tensile strength, and elastic and storage moduli. Whereas, they decline the elongation and loss factor. The very few examples of the MPNPs incorporated polymeric nanocomposites have been unstudied from this perspective. Thus, these tangible knowledge can profit scalable production of this kind of nanocomposite materials for different applications in a cost/energy efficient manner.Peer reviewe

Acellular Bone Marrow Extracts Significantly Enhance Engraftment Levels of Human Hematopoietic Stem Cells in Mouse Xeno-Transplantation Models

Hematopoietic stem cells (HSC) derived from cord blood (CB), bone marrow (BM), or mobilized peripheral blood (PBSC) can differentiate into multiple lineages such as lymphoid, myeloid, erythroid cells and platelets. The local microenvironment is critical to the differentiation of HSCs and to the preservation of their phenotype in vivo. This microenvironment comprises a physical support supplied by the organ matrix as well as tissue specific cytokines, chemokines and growth factors. We investigated the effects of acellular bovine bone marrow extracts (BME) on HSC in vitro and in vivo. We observed a significant increase in the number of myeloid and erythroid colonies in CB mononuclear cells (MNC) or CB CD34+ cells cultured in methylcellulose media supplemented with BME. Similarly, in xeno-transplantation experiments, pretreatment with BME during ex-vivo culture of HSCs induced a significant increase in HSC engraftment in vivo. Indeed, we observed both an increase in the number of differentiated myeloid, lymphoid and erythroid cells and an acceleration of engraftment. These results were obtained using CB MNCs, BM MNCs or CD34+ cells, transplanted in immuno-compromised mice (NOD/SCID or NSG). These findings establish the basis for exploring the use of BME in the expansion of CB HSC prior to HSC Transplantation. This study stresses the importance of the mechanical structure and soluble mediators present in the surrounding niche for the proper activity and differentiation of stem cells