Study of the influence of various types of incentives upon learning

The present review of the problem of incentives to learning gives some indication of the vast field which this subject covers, and of the comparatively minute amount of thorough-going research which has as yet been undertaken in the field. The value of a greater understanding of the incentive problem is clear if the studies made upon the wide discrepancies which exist between the A.Q. and the I.Q. can be used as a basis for judgment. Attention, intention, and attitude appear to be important factors in the learning process and if these can be increased and improved upon for good by the use of wisely administered incentives the case for each end every type of incentive is strengthened. The past quarter of a century has witnessed an amazing growth in the study of the underlying factors which determine man's behaviour. As these factors become better understood and classified the problem of relating environmental stimuli to them in order to obtain desired results becomes apparent. This relationship tends to present the incentive problem in a new light, as incentives come no longer to be considered as isolated factors in human behaviour but as closely allied elements, or better still as component parts of the total problem of human motivation. A review of the present existent theories of motivation show at least several fundamental urges or drives dominant in man and sensitive to external stimuli. Regardless of the interpretation given them by the various schools of psychology, the existence of certain fundamental motivating factors such as the desire for social approval, pugnacity etc. are recognized by most to be powerful determining elements in man's behaviour. The various types of expression which these inner drives take are important aspects of the problem of human behaviour. The better they become understood the more possibility is given to the hope of directing man's activity into desired channels. It has been pointed out in this study that if man's behaviour is determined by inner drives, urges, or instincts attempts to stimulate activity must take these into account and ally the external situation with the latent innate tendencies which in turn stimulate the individual into activity. External situations which do this have been classified as incentives. An analysis of the problem of incentives reveals several attributes which may be associated with them. Foremost among these is this factor made clear in the definition of incentives as used in this study, of the close relationship between incentives and the motivating elements in life. It has been suggested that this may account for a second rather generally recognized aspect of the incentive problem, that of the inter-dependence and inter-relationship. of the various incentives themselves. It has been pointed out further that before any incentive can be properly evaluated it must be considered in lip:ht of the total situation. of which it is a part. Moreover it must be recognized that the value of an incentive may differ at different times and in varying circumstances. Many incentives are thus far. little understood except to be vaguely recognized as being possible sources of stimuli. Others which are more generally recognized and which lend themselves more readily to research have been studied to some degree. The fore-going review of this experimental work reveals a great amount of material but one is readily struck by the lack of unity and thorough-going character of the research on any single incentive. Because of this fact an attempt has been made in this study to confine the experimental investigations to one type of incentive, namely, competition, and by so doing attempt to aid in the presentation of a more complete analysis of the development of the competitive spirit in children and adults. Previous studies have revealed that the competitive impulse probably makes its appearance at the age of three or four years, usually resulting in a decrease in output of work until about the age of five when the child begins to exert positive effort to out-do his fellow-worker and thus increase his efficiency. By the age of six it is thought that 90. of all children have the competitive impulse well developed. The investigations of this study dealt with three different age groups, namely, 9.5 years, 12 years, and university age. 'From the results obtained and insofar as competition was present as an incentive with the type of problem employed in this study, the following conclusions may be drawn regarding competition as an incentive: I. With children of 9.5 years of age both group competition and individual competition of the type employed in this study are effective in stimulating a greater amount of learning than results from mere practice. Group competition, however, has a greater effect than does individual competition. II. With 12 year old children both types of competition are also effective but individual competition more so than group competition. III. It appears from the present studies that girls are slightly more favorably affected both by competition and by practice than are boys. ion an IV. Superior subjects among older children tend to be less favorably affected by group competition than younger children of superior ability. The latter appear to be highly stimulated by it. Individual competition. proved to be more effective with superior children of the older groups than with those of the younger group. With inferior subjects individual competition produces a lower percentage of increase than does either group competition or mere practice. This was true in all three age groups studied. V. Contrary to prevalent belief the presence of competition as an incentive tends to increase rather than decrease accuracy. VI. Learning which takes place under the influence of competition as an incentive has a permanent effect both after one month and three month intervals. The percentage of retention is greater in the case of the older children than of the younger, in the type of learning and under the conditions employed in this study. There remains much to be done in the way of experimental research before any adequate summary of the problem of competition as an incentive can be given. Further investigations are needed with adult subjects. The inadequacy of the present study dealing with adults, and of those carried on by one or two other investigators serve to emphasize this need. Other types of learning need to be tested under the influence of competition; the relationship between the I.Q. and responses to competition needs investigation.; and many comparative studies should be made between the effects of competition and other incentives. It is hoped that some of these investigations may be undertaken at a later date. In summary, the competitive impulse, well-developed at the age of six appears to grow in strength throughout childhood and at the age of nine expresses itself most strongly in the form of response to group competition. At the age of twelve the emphasis appears to have shifted and individual competition proves to be more stimulating than group competition, at least in the type of problem used in this study. Indications suggest that perhaps as age increases the effect of group competition diminishes, and other factors enter in which have a strong additional incentive value. An understanding of what these may be and their relative strengths awaits further research

Platelet-mediated metabolism of the common dietary flavonoid, quercetin.

BACKGROUND: Flavonoid metabolites remain in blood for periods of time potentially long enough to allow interactions with cellular components of this tissue. It is well-established that flavonoids are metabolised within the intestine and liver into methylated, sulphated and glucuronidated counterparts, which inhibit platelet function. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrate evidence suggesting platelets which contain metabolic enzymes, as an alternative location for flavonoid metabolism. Quercetin and a plasma metabolite of this compound, 4'-O-methyl quercetin (tamarixetin) were shown to gain access to the cytosolic compartment of platelets, using confocal microscopy. High performance liquid chromatography (HPLC) and mass spectrometry (MS) showed that quercetin was transformed into a compound with a mass identical to tamarixetin, suggesting that the flavonoid was methylated by catechol-O-methyl transferase (COMT) within platelets. CONCLUSIONS/SIGNIFICANCE: Platelets potentially mediate a third phase of flavonoid metabolism, which may impact on the regulation of the function of these cells by metabolites of these dietary compounds

The secretome of alginate-encapsulated limbal epithelial stem cells modulates corneal epithelial cell proliferation

Limbal epithelial stem cells may ameliorate limbal stem cell deficiency through secretion of therapeutic proteins, delivered to the cornea in a controlled manner using hydrogels. In the present study the secretome of alginate-encapsulated limbal epithelial stem cells is investigated. Conditioned medium was generated from limbal epithelial stem cells encapsulated in 1.2% (w/v) calcium alginate gels. Conditioned medium proteins separated by 1-D gel electrophoresis were visualized by silver staining. Proteins of interest including secreted protein acidic and rich in cysteine, profilin-1, and galectin-1 were identified by immunoblotting. The effect of conditioned medium (from alginate-encapsulated limbal epithelial stem cells) on corneal epithelial cell proliferation was quantified and shown to significantly inhibit (P</=0.05) their growth. As secreted protein acidic and rich in cysteine was previously reported to attenuate proliferation of epithelial cells, this protein may be responsible, at least in part, for inhibition of corneal epithelial cell proliferation. We conclude that limbal epithelial stem cells encapsulated in alginate gels may regulate corneal epithelialisation through secretion of inhibitory proteins

Transport of cells in hydrogels

The present invention relates to hydrogels which may be used to encapsulate or entrap live cells. The invention further relates to methods for transporting live cells which are encapsulated or entrapped within hydrogels from a first location to a second location. The invention further relates to method of treating a wound, disease or tissue injury, e.g. an ocular injury or a damaged ocular surface in a subject using a hydrogel comprising corneal stem cells. The hydrogels used in such methods may be ones which have been transported from a first location to a second location

A simple and robust method for pre-wetting poly (lactic-co-glycolic) acid microspheres

Poly (lactic-co-glycolic) acid microspheres are amenable to a number of biomedical procedures that support delivery of cells, drugs, peptides or genes. Hydrophilisation or wetting of poly (lactic-co-glycolic) acid are an important pre-requisites for attachment of cells and can be achieved via exposure to plasma oxygen or nitrogen, surface hydrolysis with NaOH or chloric acid, immersion in ethanol and water, or prolonged incubation in phosphate buffered saline or cell culture medium. The aim of this study is to develop a simple method for wetting poly (lactic-co-glycolic) acid microspheres for cell delivery applications. A one-step ethanol immersion process that involved addition of serum-supplemented medium and ethanol to PLGA microspheres over 30 min–24 h is described in the present study. This protocol presents a more efficient methodology than conventional two-step wetting procedures. Attachment of human skeletal myoblasts to poly (lactic-co-glycolic) acid microspheres was dependent on extent of wetting, changes in surface topography mediated by ethanol pre-wetting and serum protein adsorption. Ethanol, at 70% (v/v) and 100%, facilitated similar levels of wetting. Wetting with 35% (v/v) ethanol was only achieved after 24 h. Pre-wetting (over 3 h) with 70% (v/v) ethanol allowed significantly greater (p ≤ 0.01) serum protein adsorption to microspheres than wetting with 35% (v/v) ethanol. On serum protein-loaded microspheres, greater numbers of myoblasts attached to constructs wetted with 70% ethanol than those partially wetted with 35% (v/v) ethanol. Microspheres treated with 70% (v/v) ethanol presented a more rugose surface than those treated with 35% (v/v) ethanol, indicating that more efficient myoblast adhesion to the former may be at least partially attributed to differences in surface structure. We conclude that our novel protocol for pre-wetting poly (lactic-co-glycolic) acid microspheres that incorporates biochemical and structural features into this biomaterial can facilitate myoblast delivery for use in clinical settings.This project was supported by grants from the UK Medical Research Council (MR/L002752/1) and Sir Halley Stewart Trust. The research was undertaken at UCL/UCLH which receives funding from the Department of Health’s NIHR as a Comprehensive Biomedical Research Centre.Published versio

GRID and docking analyses reveal a molecular basis for flavonoid inhibition of src-family kinase activity

Flavonoids reduce cardiovascular disease risk through anti-inflammatory, anti-coagulant and anti-platelet actions. One key flavonoid inhibitory mechanism is blocking kinase activity that drives these processes. Flavonoids attenuate activities of kinases including phosphoinositide-3-kinase (PI3K), Fyn, Lyn, Src, Syk, PKC, PIM1/2, ERK, JNK, and PKA. X-ray crystallographic analyses of kinase-flavonoid complexes show that flavonoid ring systems and their hydroxyl substitutions are important structural features for their binding to kinases. A clearer understanding of structural interactions of flavonoids with kinases is necessary to allow construction of more potent and selective counterparts. We examined flavonoid (quercetin, apigenin and catechin) interactions with Src-family kinases (Lyn, Fyn and Hck) applying the Sybyl docking algorithm and GRID. A homology model (Lyn) was used in our analyses to demonstrate that high quality predicted kinase structures are suitable for flavonoid computational studies. Our docking results revealed potential hydrogen bond contacts between flavonoid hydroxyls and kinase catalytic site residues. Identification of plausible contacts indicated that quercetin formed the most energetically stable interactions, apigenin lacked hydroxyl groups necessary for important contacts, and the non-planar structure of catechin could not support predicted hydrogen bonding patterns. GRID analysis using a hydroxyl functional group supported docking results. Based on these findings, we predicted that quercetin would inhibit activities of Src-family kinases with greater potency than apigenin and catechin. We validated this prediction using in vitro kinase assays. We conclude that our study can be used as a basis to construct virtual flavonoid interaction libraries to guide drug discovery using these compounds as molecular templates

Platelet-Mediated Metabolism of the Common Dietary Flavonoid, Quercetin

Abstract Background: Flavonoid metabolites remain in blood for periods of time potentially long enough to allow interactions with cellular components of this tissue. It is well-established that flavonoids are metabolised within the intestine and liver into methylated, sulphated and glucuronidated counterparts, which inhibit platelet function

Enhanced viability of corneal epithelial cells for efficient transport/storage using a structurally-modified calcium alginate hydrogel

Aims: Therapeutic limbal epithelial stem cells could be managed more efficiently if clinically validated batches were transported for ‘on-demand’ use. Materials & methods: In this study, corneal epithelial cell viability in calcium alginate hydrogels was examined under cell culture, ambient and chilled conditions for up to 7 days. Results: Cell viability improved as gel internal pore size increased, and was further enhanced with modification of the gel from a mass to a thin disc. Ambient storage conditions were optimal for supporting cell viability in gel discs. Cell viability in gel discs was significantly enhanced with increases in pore size mediated by hydroxyethyl cellulose. Conclusion: Our novel methodology of controlling alginate gel shape and pore size together provides a more practical and economical alternative to established corneal tissue/cell storage methods