Κατανοώντας την έννοια της περιεκτικότητας διαλυμάτων με την μέθοδο της καθοδηγούμενης ανακάλυψης (GUIDED DISCOVERY)

Σκοπός της εργασίας μας ήταν η μελέτη της επίδρασης της καθοδηγούμενη ανακάλυψης στη μάθηση. Θέλαμε να μελετήσουμε, αν η καθοδηγούμενη ανακάλυψη μπορεί να επιφέρει καλύτερες επιδόσεις στο μάθημα της Χημείας στην Α΄Λυκείου ανεξαρτήτως φύλου και προτέρων επιδόσεων (προστιθέμενη αξία ). Οργανώσαμε τη διδασκαλία μας σε δύο ενότητες που σχετίζονται μεταξύ τους: Στην ενότητα της έκφρασης περιεκτικότητας διαλυμάτων Και στην ενότητα της συγκέντρωσης διαλυμάτων Τα βήματα που ακολουθήσαμε για την υλοποίηση της έρευνας είχαν ως εξής: 1. Μελετήσαμε τη σχετική βιβλιογραφία και τις διπλωματικές εργασίες που έχουν εκπονηθεί στο ΔΙΧΗΝΕΤ. 2. Φτιάξαμε φύλλα εργασίας ( 1 φύλλο εργασίας για την κάθε ενότητα), κάρτα εξόδου και διαφάνειες παρουσίασης (power point). 3. Κάναμε την έρευνά μας σε 4 τμήματα της Α` Λυκείου ( 2 πειραματικά και 2 ελέγχου). Στις ομάδες ελέγχου κάναμε παραδοσιακή διδασκαλία, ενώ στις πειραματικές έγινε 20λεπτη διδασκαλία με διαφάνειες και ακολούθησε έρευνα με φύλλα εργασίας με καθοδηγούμενη ανακάλυψη, που περιείχε και πειραματικό κομμάτι. 4. Σ` όλες τις ομάδες δόθηκε τεστ προ-ελέγχου και τεστ μετα-ελέγχου και 5λεπτη κάρτα εξόδου. 5. Και στα τέσσερα δίωρα της πειραματικής έρευνας έγινε παρακολούθηση της παρέμβασης από την Δρ. κα Κουλουμπαρίτση. 6. Δεν βρέθηκε σημαντική στατιστική διαφορά ανάμεσα στην επίδοση της πειραματικής ομάδας, συγκριτικά με την ομάδα ελέγχου. 7. Δεν βρέθηκε σημαντική στατιστική διαφορά στις επιδόσεις ανάμεσα στους χαμηλόβαθμους, στους μέτριους και υψηλόβαθμους μαθητές. Καταλήξαμε στο συμπέρασμα ότι η καθοδηγούμενη ανακάλυψη για να αξιοποιηθεί σωστά και να δώσει καλύτερα αποτελέσματα, απαιτεί άρτια και χρονοβόρα προετοιμασία από τον εκπαιδευτικό, και πρέπει να δοθεί περισσότερος χρόνος στους μαθητές (συνεχόμενο δίωρο) για να εκτελέσουν πειράματα, να συνεργαστούν σε ομάδες και για να απαντήσουν στα φύλλα εργασίας. Η αλλαγή της σχολικής κουλτούρας και η υιοθέτηση νέων μεθόδων διδασκαλίας, όπως η καθοδηγούμενη ανακάλυψη, σε χώρους «αφιλόξενους» όπως είναι τα ενιαία λύκεια και γυμνάσια, προϋποθέτει μείωση ύλης, επιμόρφωση εκπαιδευτικών και έμφαση στην ανάλυση προγραμμάτων σε μεθόδους που καλλιεργούν τη βαθιά κατανόηση και την κριτική σκέψη.We have observed that guided discovery can benefit students in the cognitive domain in Chemistry of 1st year Lyceum regardless of their sex (male or female) and prior knowledge The teaching was divided into two closely related units which were: UNIT 1: Content of solutions UNIT 2 : Concentration of solutions (dilution, condensation & mixing of solutions). The implementation of the research work was conducted in the followings steps: 1. Creation of worksheets, exit cards and power point presentations. 2. Utilization of 4 classes of the 1st grade of senior high school in our research inform of 2 experimental groups and 2 controls groups. 3. Conventional teaching methods were used in the control groups however a twenty-minute tutorial with power point presentation followed by research with guided discovery were used in the experimental groups 4. At the end of each research, each group received a 5-minute exit card under the supervision of Doctor Kouloumbaritsi. 5. A significant statistical difference was not observed between the benefits of the experimental groups in comparison with the control groups. 6. Not found significant statistical difference between boys and girls. Consequently we reached the conclusion that in order to be more successful guided discovery, should be thoroughly organised by the educator and more time should be given to the students

Electrically tunable plasmonic metasurface as a matrix of nanoantennas

We report the fabrication and characterization of a plasmonic metasurface comprising electrically contacted sub-wavelength gold dipole nanoantennas, conformally coated by a thin hafnia film, an indium tin oxide layer and a backside mirror, forming metal-oxide-semiconductor (MOS) capacitors, for use as an electrically-tunable reflectarray or metasurface. By voltage biasing the nanoantennas through metallic connectors and leveraging the carrier refraction effect in the MOS capacitors, our measurements demonstrate phase control in reflection over a range of about 30 degrees, with a constant magnitude of reflection coefficient of 0.5, and the absence of secondary lobes. Comprehensive electromagnetic and quantum carrier models of the structure are developed and are in excellent agreement with the measurements. The metasurface holds promise for use as an optical phased array.Comment: 17 pages, 6 figure

GSTM1, GSTT1 and GSTP1 Polymorphisms in the Korean Population

The isoenzymes of the glutathione s transferase (GST) family play a vital role in phase II of biotransformation of many substances. Using a multiplex polymerase chain reaction and a direct sequencing analysis, the frequencies of GSTM1, GSTT1, and GSTP1 polymorphisms were evaluated in 1,051 Korean male subjects. We found that 53.8% of the individuals had the GSTM1 null genotype and 54.3% had the GSTT 1 null genotype. The genotypic distribution of GSTP1 was Ile105/Ile105 in 68.4%, Ile105/Val105 in 29.1% and Val105/Val105 in 2.5%. The most frequently observed combination of GSTM1, GSTP1 and GSTT1 genotypes was Null type/Ile105/Ile105/Null type, while the combination of Non-null type/Val105/Val105/Non-Null type was not observed. We found that the genotype distributions of three GST isoenzymes in the Koreans are similar to those reported in Asians and previously reported Koreans. We believe our results, which are represented by a large population, are reliable estimates of the frequencies of the polymorphic GST alleles in the Koreans and will help future researches on GST polymorphisms

Glutathione S-transferase Pi mediates proliferation of androgen-independent prostate cancer cells

Prostate cancers generally acquire an androgen-independent growth capacity with progression, resulting in resistance to antiandrogen therapy. Therefore, identification of the genes regulated through this process may be important for understanding the mechanisms of prostate carcinogenesis. We here utilized androgen-dependent/independent transplantable tumors, newly established with the ‘transgenic rat adenocarcinoma in prostate’ (TRAP) model, to analyze their gene expression using microarrays. Among the overexpressed genes in androgen-independent prostate cancers compared with the androgen-dependent tumors, glutathione S-transferase pi (GST-pi) was included. In line with this, human prostate cancer cell lines PC3 and DU145 (androgen independent) had higher expression of GST-pi compared with LNCaP (androgen dependent) as determined by semiquantitative reverse transcription–polymerase chain reaction analysis. To investigate the roles of GST-pi expression in androgen-independent human prostate cancers, GST-pi was knocked down by a small interfering RNA (siRNA), resulting in significant decrease of the proliferation rate in the androgen-independent PC3 cell line. In vivo, administration of GST-pi siRNA–atelocollagen complex decreased GST-pi protein expression, resulting in enhanced numbers of TdT mediated dUTP-biotin nick-end labering (TUNEL)-positive apoptotic cells. These findings suggest that GST-pi might play important roles in proliferation of androgen-independent human prostate cancer cells

Cathepsin D SNP associated with increased risk of variant Creutzfeldt-Jakob disease

<p>Abstract</p> <p>Background</p> <p>Variant Creutzfeldt-Jakob disease (vCJD) originally resulted from the consumption of foodstuffs contaminated by bovine spongiform encephalopathy (BSE) material, with 163 confirmed cases in the UK to date. Many thousands are likely to have been exposed to dietary infection and so it is important (for surveillance, epidemic modelling, public health and understanding pathogenesis) to identify genetic factors that may affect individual susceptibility to infection. This study looked at a polymorphism in the cathepsin D gene (refSNP ID: rs17571) previously examined in Alzheimer's disease (AD).</p> <p>Methods</p> <p>Blood samples taken from 110 vCJD patients were tested for the C-T base change, and genotype data were compared with published frequencies for a control population using multiple logistic regression.</p> <p>Results</p> <p>There was a significant excess of the cathepsin D polymorphism TT genotype in the vCJD cohort compared to controls. The TT genotype was found to have a 9.75 fold increase in risk of vCJD compared to the CT genotype and a 10.92 fold increase compared to the CC genotype.</p> <p>Conclusion</p> <p>This mutation event has been observed to alter the protease activity of the cathepsin D protein and has been linked to an increase in amyloid beta plaque formation in AD. vCJD neuropathology is characterised by the presence of amyloid plaques, formed from the prion protein, and therefore alterations in the amyloid processing activity of cathepsin D may affect the neuropathogenesis of this disease.</p

Polymorphisms of glutathione-S-transferase M1, T1, P1 and the risk of prostate cancer: a case-control study

<p>Abstract</p> <p>Background</p> <p>It has been suggested that polymorphisms in glutathione-<it>S</it>-transferases (GST) could predispose to prostate cancer through a heritable deficiency in detoxification pathways for environmental carcinogens. Yet, studies linking <it>GST </it>polymorphism and prostate cancer have so far failed to unambiguously establish this relation in patients. A retrospective study on healthy, unrelated subjects was conducted in order to estimate the population <it>GST </it>genotype frequencies in the Slovak population of men and compare our results with already published data (GSEC project-Genetic Susceptibility to Environmental Carcinogens). A further aim of the study was to evaluate polymorphisms in <it>GST </it>also in patients with prostate cancer in order to compare the evaluated proportions with those found in the control subjects.</p> <p>Methods</p> <p>We determined the <it>GST </it>genotypes in 228 healthy, unrelated subjects who attended regular prostate cancer screening between May 2005 and June 2007 and in 129 histologically verified prostate cancer patients. Analysis for the <it>GST </it>gene polymorphisms was performed by PCR and PCR-RFLP.</p> <p>Results</p> <p>We found that the <it>GST </it>frequencies are not significantly different from those estimated in a European multicentre study or from the results published by another group in Slovakia. Our results suggest that <it>Val/Val </it>genotype of <it>GSTP1 </it>gene could modulate the risk of prostate cancer, even if this association did not reach statistical significance. We did not observe significantly different crude rates of the <it>GSTM1 </it>and <it>GSTT1 </it>null genotypes in the men diagnosed with prostate cancer and those in the control group.</p> <p>Conclusion</p> <p>Understanding the contribution of <it>GST </it>gene polymorphisms and their interactions with other relevant factors may improve screening diagnostic assays for prostate cancer. We therefore discuss issues of study feasibility, study design, and statistical power, which should be taken into account in planning further trials.</p

Association between RUNX3 promoter methylation and gastric cancer: a meta-analysis

<p>Abstract</p> <p>Background</p> <p>Runt-related transcription factor 3 (RUNX3) is a member of the runt-domain family of transcription factors and has been reported to be a candidate tumor suppressor in gastric cancer. However, the association between RUNX3 promoter methylation and gastric cancer remains unclear.</p> <p>Methods</p> <p>We systematically reviewed studies of RUNX3 promoter methylation and gastric cancer published in English or Chinese from January 2000 to January 2011, and quantified the association between RUNX3 promoter methylation and gastric cancer using meta-analysis methods.</p> <p>Results</p> <p>A total of 1740 samples in 974 participants from seventeen studies were included in the meta-analysis. A significant association was observed between RUNX3 promoter methylation and gastric cancer, with an aggregated odds ratio (OR) of 5.63 (95%CI 3.15, 10.07). There was obvious heterogeneity among studies. Subgroup analyses (including by tissue origin, country and age), meta-regression were performed to determine the source of the heterogeneity. Meta-regression showed that the trend in ORs was inversely correlated with age. No publication bias was detected. The ORs for RUNX3 methylation in well-differentiated <it>vs </it>undifferentiated gastric cancers, and in intestinal-type <it>vs </it>diffuse-type carcinomas were 0.59 (95%CI: 0.30, 1.16) and 2.62 (95%CI: 1.33, 5.14), respectively. There were no significant differences in RUNX3 methylation in cancer tissues in relation to age, gender, TNM stage, invasion of tumors into blood vessel or lymphatic ducts, or tumor stage.</p> <p>Conclusions</p> <p>This meta-analysis identified a strong association between methylation of the RUNX3 promoter and gastric cancer, confirming the role of RUNX3 as a tumor suppressor gene.</p

Probing the Interstellar Medium in Early type galaxies with ISO observations

Four IRAS-detected early type galaxies were observed with ISO. With the exception of the 15 micron image of NGC1052, the mid-IR emission from NGC1052, NGC1155, NGC5866 and NGC6958 at 4.5, 7 and 15 microns show extended emission. Mid-IR emission from NGC1052, NGC1155, and NGC6958 follows a de Vaucouleurs profile. The ratio of 15/7 micron flux decreases with radius in these galaxies, approaching the values empirically observed for purely stellar systems. In NGC5866, the 7 and 15 micron emission is concentrated in the edge-on dust lane. All the galaxies are detected in the [CII] line, and the S0s NGC1155 and NGC5866 are detected in the [OI] line as well. The ISO-LWS observations of the [CII] line are more sensitive measures of cool, neutral ISM than HI and CO by about a factor of 10-100. Three of four early type galaxies, namely NGC1052, NGC6958 and NGC5866, have low ratio FIR/Blue and show a lower [CII]/FIR, which is due to a softer radiation field from old stellar populations. The low [CII]/CO ratio in NGC5866 ([CII]/CO(1-0) < 570) confirms this scenario. We estimate the UV radiation expected from the old stellar populations in these galaxies and compare it to that needed to heat the gas to account for the cooling observed [CII] and [OI] lines. In three out of four galaxies, NGC1052, NGC5866 and NGC6958, the predicted UV radiation falls short by a factor of 2-3. In view of the observed intrinsic scatter in the "UV-upturn" in elliptical galaxies and its great sensitivity to age and metallicity effects, this is not significant. However, the much larger difference (about a factor of 20) between the UV radiation from old stars and that needed to produce the FIR lines for NGC 1155 is strong evidence for the presence of young stars, in NGC1155.Comment: To appear in the Astrophysical Journal. Figure 1 appears as a separate jpg figur