E-LEARNING: LE TECNOLOGIE DI RETE A SUPPORTO DELL'APPRENDIMENTO. STRUMENTI E MODELLI PER LA DIDATTICA UNIVERSITARIA

Questo lavoro muove dal riconoscere il valore fondamentale ricoperto dalla conoscenza teorica e pratica all’interno della contemporanea società dell’informazione. L’avvento e diffusione delle ICT, in particolare Internet, ha modificato profondamente i processi cognitivi, i comportamenti umani, le modalità di accedere all’informazione e di comunicare. Tali cambiamenti socio-culturali, che influenzano i processi di produzione e scambio della conoscenza, hanno inevitabili ricadute anche sui modelli di insegnamento/apprendimento. Ciò produce una rivoluzione radicale in ambito didattico-pedagogico. Sulla base di questi presupposti, la finalità della presente ricerca è di trattare in maniera esauriente l’attualissima tematica dell’e-learning, ovvero della formazione compiuta tramite le tecnologie di rete ed erogata in ambienti di apprendimento virtuali. Nella prima parte del testo si fa riferimento ai principali studi teorici, volti ad indagare i rapporti tra tecnologie digitali e modelli didattici, focalizzando l’attenzione in particolare sui modelli comunicativi, relazionali, sociologici e pedagogici. L’accento verte soprattutto sull’importanza attribuita alla dimensione sociale del processo di apprendimento e sulle dinamiche interpersonali di costruzione collaborativa della conoscenza, principi cardine del pensiero costruttivista. Si mettono, inoltre, in evidenza gli interrogativi ricorrenti nell’attuale dibattito sull’argomento, peraltro ancora aperto, e si tenta di proporre possibili strategie o soluzioni alle problematiche esistenti, con l’obiettivo di rendere la formazione online ancora più efficace. Terminato l’excursus teorico ed individuate le principali caratteristiche del tema, si è deciso di adottare un’impostazione maggiormente pratica. Nella seconda parte viene compiuta l’analisi di due differenti esperienze di e-learning attuate presso l’Ateneo Pisano, con la valutazione dei risultati e della loro effettiva utilità. L’indagine si concentra, quindi, sulla didattica istituzionale, in particolare quella accademico-universitaria, e cerca di comprendere in che direzione essa stia cambiando. Giunti al termine della riflessione, la conclusione è che non sia possibile fornire una definizione univoca del concetto di e-learning, poiché si tratta di un fenomeno estremamente complesso e vario, che assume connotazioni diverse a seconda del contesto di applicazione e delle concrete esigenze formative. Nel valutare l’opportunità di ricorrere a strategie didattiche in rete non è sufficiente, quindi, prendere in considerazione solamente l’aspetto tecnologico; sarebbe invece opportuno considerare, caso per caso e simultaneamente, un gran numero di fattori

Anti-inflammatory activity of electron-deficient organometallics

YesWe report an evaluation of the cytotoxicity of a series of electron-deficient (16-electron) half-sandwich precious metal complexes of ruthenium, osmium and iridium ([Os/Ru(η6-pcymene)( 1,2-dicarba-closo-dodecarborane-1,2-dithiolato)] (1/2), [Ir(η5-pentamethylcyclopentadiene)(1,2-dicarba-closo-dodecarborane- 1,2-dithiolato)] (3), [Os/Ru(η6-p-cymene)(benzene-1, 2-dithiolato)] (4/5) and [Ir(η5-pentamethylcyclopentadiene) (benzene-1,2-dithiolato)] (6)) towards RAW 264.7 murine macrophages and MRC-5 fibroblast cells. Complexes 3 and 6 were found to be non-cytotoxic. The anti-inflammatory activity of 1–6 was evaluated in both cell lines after nitric oxide (NO) production and inflammation response induced by bacterial endotoxin lipopolysaccharide (LPS) as the stimulus. All metal complexes were shown to exhibit dose-dependent inhibitory effects on LPS-induced NO production on both cell lines. Remarkably, the two iridium complexes 3 and 6 trigger a full anti-inflammatory response against LPS-induced NO production, which opens up new avenues for the development of non-cytotoxic anti-inflammatory drug candidates with distinct structures and solution chemistry from that of organic drugs, and as such with potential novel mechanisms of action.We thank the Royal Society (University Research Fellowship No. UF150295 to NPEB), and the University of Bradford for financial support

Enhancement of Cytotoxicity by Combining Pyrenyl-Dendrimers and Arene Ruthenium Metallacages

Three generations of pyrenyl bis-MPA dendrimers with two different end-groups, acetonide (pyrGn) or alcohol (pyrGn-OH) (n = 1–3), were synthesized, and the pyrenyl group of the dendritic molecules was encapsulated in the arene ruthenium metallacages, [Ru6(p-cymene) 6 (OO∩OO)3(tpt)2]6+ (OO∩OO = 5,8-dioxydo- 1,4-naphtaquinonato (donq) [1]6+ and 6,11-dioxydo-5,12- naphtacenedionato (dotq) [2]6+; tpt =2,4,6-tri(pyridin-4-yl)-1,3,5-triazine). The host–guest properties of [guestC1]6+ and [guestC2]6+ were studied in solution by NMR and UV–vis spectroscopic methods, thus allowing the determination of the affinity constants. Moreover, the cytotoxicity of these water- soluble host–guest systems and the pyrenyl-dendrimers was evaluated on human ovarian cancer cells

The synthesis and unexpected solution chemistry of thermochromic carborane-containing osmium half-sandwich complexes

YesThe functionalisation of the 16-electron complex [Os(η6-p-cymene)(1,2-dicarba-closo-dodecarborane- 1,2-dithiolato)] (1) with a series of Lewis bases to give the 18-electron complexes of general formula [Os(η6-p-cymene)(1,2-dicarba-closo-dodecarborane-1,2-dithiolato)(L)] (L = pyridine (2), 4-dimethylaminopyridine (3), 4-cyanopyridine (4), 4-methoxypyridine (5), pyrazine (6), pyridazine (7), 4,4’-bipyridine (8) and triphenylphosphine (9)) is reported. All 18-electron complexes are in equilibrium in solution with the 16-electron precursor, and thermochromic properties are observed in some cases (2, 3, 5, 8, and 9). The binding constants and Gibbs free energies of the equilibria are determined using UV-visible titrations and their stabilities investigated. Synthetic routes for forcing the formation of the 18-electron species are proposed, and analytical methods to characterise the equilibria are described.We thank the Leverhulme Trust (Early Career Fellowship No. ECF-2013-414 to NPEB), and the University of Warwick (Grant No. RD14102 to NPEB)

Aplikasi Terrestrial Laser Scanner Untuk Pemodelan Tampak Muka Bangunan (Studi Kasus: Gedung PT. Almega Geosystems, Kelapa Gading-Jakarta)

Perkembangan dunia survei dan pemetaan sangatlah pesat. Di era sekarang ini, pemanfaatan teknologi Terrestrial Laser Scanner dapat memberikan solusi untuk pendokumentasian suatu bangunan maupun pengukuran topografi. Teknologi ini dinilai sangat efisien jika dibandingkan dengan teknologi pengukuran lainnya. Hasil pengukuran Terrestrial Laser Scanner berupa point clouds yang mempunyai koordinat 3 dimensi. Dalam tugas akhir ini, metode pengukuran Terrestrial Laser Scanner digunakan untuk pemodelan tampak muka bangunan gedung PT. Almega Geosystems, Kelapa Gading-Jakarta. Proses akuisisi data di lapangan dan pengolahan data menggunakan software Cyclone V.7.4 (compatible with Leica Scan Station 2). Hasil akhir dalam penelitian ini adalah model tampak muka bangunan gedung PT. Almega Geosystems, Kelapa Gading-Jakarta. Pengujian hasil pengolahan model dilakukan dengan dua pengujian, yaitu perbandingan jarak antar sisi gedung hasil pengukuran Electronic Total Station dan laser disto meter. Nilai rata-rata kesalahan dari perbandingan jarak antar sisi mengunakan Electronic Total Station sebesar 0.00527 meter dan nilai rata-rata kesalahan dari perbandingan jarak antar sisi dengan laser disto meter sebesar 0.00708 meter

Barley beta-glucan promotes MnSOD expression and enhances angiogenesis under oxidative microenvironment

Manganese superoxide dismutase (MnSOD), a foremost antioxidant enzyme, plays a key role in angiogenesis. Barley-derived (1.3) β-D-glucan (β-D-glucan) is a natural water-soluble polysaccharide with antioxidant properties. To explore the effects of β-D-glucan on MnSOD-related angiogenesis under oxidative stress, we tested epigenetic mechanisms underlying modulation of MnSOD level in human umbilical vein endothelial cells (HUVECs) and angiogenesis in vitro and in vivo. Long-term treatment of HUVECs with 3% w/v β-D-glucan significantly increased the level of MnSOD by 200±2% compared to control and by 50±4% compared to untreated H2O2-stressed cells. β-D-glucan-treated HUVECs displayed greater angiogenic ability. In vivo, 24h-treatment with 3% w/v β-D-glucan rescued vasculogenesis in Tg (kdrl: EGFP) s843Tg zebrafish embryos exposed to oxidative microenvironment. HUVECs overexpressing MnSOD demonstrated an increased activity of endothelial nitric oxide synthase (eNOS), reduced load of superoxide anion (O2-) and an increased survival under oxidative stress. In addition, β-D-glucan prevented the rise of hypoxia inducible factor (HIF)1-α under oxidative stress. The level of histone H4 acetylation was significantly increased by β-D-glucan. Increasing histone acetylation by sodium butyrate, an inhibitor of class I histone deacetylases (HDACs I), did not activate MnSOD-related angiogenesis and did not impair β-D-glucan effects. In conclusion, 3% w/v β-D-glucan activates endothelial expression of MnSOD independent of histone acetylation level, thereby leading to adequate removal of O2-, cell survival and angiogenic response to oxidative stress. The identification of dietary β-D-glucan as activator of MnSOD-related angiogenesis might lead to the development of nutritional approaches for the prevention of ischemic remodeling and heart failure

Ghrelin regulates proliferation and differentiation of osteoblastic cells

Abstract It has previously been reported that growth hormone secretagogues (GHS) may have a role in the regulation of bone metabolism in animals and humans. In this study we evaluated the effect of ghrelin, the endogenous ligand of GHS receptors, on the proliferation rate and on osteoblast activity in primary cultures of rat calvaria osteoblasts. In the same experiments, we compared the effects of ghrelin with those of hexarelin (HEXA) and EP-40737, two synthetic GHS with different characteristics. Both ghrelin and HEXA (10(-11)-10(-8) M) significantly stimulated osteoblast proliferation at low concentrations (10(-10) M). Surprisingly, EP-40737 demonstrated an antiproliferative effect at 10(-9)-10(-8) M, whereas lower concentrations had no effect on cell proliferation. Ghrelin and HEXA significantly increased alkaline phosphatase (ALP) and osteocalcin (OC) production. At variance with these peptides, EP-40737 did not significantly stimulate ALP and OC. The mRNA for GHS-R1a receptors and the corresponding protein were detected in calvarial osteoblasts by RT-PCR and Western blot respectively, indicating that ghrelin and GHS may bind and activate this specific receptor. We conclude that endogenous ghrelin and synthetic GHS modulate proliferation and differentiation of rat osteoblasts, probably by acting on their specific receptor

MicroRNA 19a replacement partially rescues fin and cardiac defects in zebrafish model of Holt Oram syndrome

Holt-Oram Syndrome (HOS) is an autosomal dominant heart-hand syndrome caused by mutations in the TBX5 gene, a transcription factor capable of regulating hundreds of cardiac-specific genes through complex transcriptional networks. Here we show that, in zebrafish, modulation of a single miRNA is sufficient to rescue the morphogenetic defects generated by HOS. The analysis of miRNA-seq profiling revealed a decreased expression of miR-19a in Tbx5-depleted zebrafish embryos compared to the wild type. We revealed that the transcription of the miR-17-92 cluster, which harbors miR-19a, is induced by Tbx5 and that a defined dosage of miR-19a is essential for the correct development of the heart. Importantly, we highlighted that miR-19a replacement is able to rescue cardiac and pectoral fin defects and to increase the viability of HOS zebrafish embryos. We further observed that miR-19a replacement shifts the global gene expression profile of HOS-like zebrafish embryos towards the wild type condition, confirming the ability of miR-19a to rescue the Tbx5 phenotype. In conclusion our data demonstrate the importance of Tbx5/miR-19a regulatory circuit in heart development and provide a proof of principle that morphogenetic defects associated with HOS can be rescued by transient miRNA modulation