Adults with dyslexia demonstrate large effects of crowding and detrimental effects of distractors in a visual tilt discrimination task

Previous research has shown that adults with dyslexia (AwD) are disproportionately impacted by close spacing of stimuli and increased numbers of distractors in a visual search task compared to controls [1]. Using an orientation discrimination task, the present study extended these findings to show that even in conditions where target search was not required: (i) AwD had detrimental effects of both crowding and increased numbers of distractors; (ii) AwD had more pronounced difficulty with distractor exclusion in the left visual field and (iii) measures of crowding and distractor exclusion correlated significantly with literacy measures. Furthermore, such difficulties were not accounted for by the presence of covarying symptoms of ADHD in the participant groups. These findings provide further evidence to suggest that the ability to exclude distracting stimuli likely contributes to the reported visual attention difficulties in AwD and to the aetiology of literacy difficulties. The pattern of results is consistent with weaker and asymmetric attention in AwD

SILVER CATALYSED INTRAMOLECULAR CYCLISATION OF 2-ALKYNYL-ACETOPHENONES AND 3-ACETYL-2-ALKYNYLPYRIDINES IN THE PRESENCE OF AMMONIA

The development of new domino approaches for the synthesis of nitrogen containing heterocycles is a research field in continuous evolution. In particular, for many years we have been interested in the synthesis of nitrogen containing rings starting from alkyne derivatives in the presence of ammonia. Recently we reported a valuable approaches to the synthesis isoquinolines starting from 2-alkynyl-benzaldehydes,2 and the approach was also successfully transformed in a multicomponent process.3 Unexpectedly, when we tried to react 2-alkynylacetophenone derivatives under optimized conditions the reaction failed. This result prompt us to investigate the reaction of alkynyl ketones more in depth. We started our study looking for the best conditions to trigger the domino reaction on a model compound. We tried some metal catalysts potentially able to promote both the imine formation as Lewis acid, and the intermolecular hydroamination step as alkynophilic catalysts.4 We were delighted to find that the metal catalysed reaction gave the desired isoquinoline, beside variable amounts of the isomeric naphthalen-1-amine. The best results were obtained with AgOTf in terms of conversion, selectivity and reaction times. Scope and limitation of the approach have been extensively studied. We found that the silver-catalyzed/microwave-promoted domino imination/annulation of alkynes bearing a proximate carbonyl group in the presence of ammonia is an interesting alternative for the synthesis of aromatic heterocycles and carbocycles. A plausible mechanism is also suggested

heavy ion effects from track structure to dna and chromosome damage

The use of carbon ions for the treatment of certain tumour types, especially radioresistant tumours, is becoming more frequent due to the carbon- ion dose localization and high relative biological effectiveness (RBE) in the Bragg peak region. Human beings can also be exposed to heavy ions in space, since galactic cosmic rays are a mixed field consisting of not only high-energy protons and He ions, but also heavier ions including iron. Due to their high linear energy transfer (LET), heavy ions have peculiar track structures, characterized by a high level of energy deposition clustering. Furthermore, high-energy ions produce energetic secondary electrons ('delta rays') which can give rise to energy depositions several micrometres away from the core of the primary particle track. Also in view of hadron therapy and space radiation applications, it is therefore important to characterize heavy-ion tracks from a physical and biophysical point of view. In this framework, herein we will discuss the main physical features of heavy-ion track structure, as well as heavy-ion-induced DNA double-strand breaks, which are regarded as one of the most important initial radiobiological lesions and chromosome aberrations, which are correlated both with cell death and with cell conversion to malignancy

History of Reading Struggles Linked to Enhanced Learning in Low Spatial Frequency Scenes

People with dyslexia, who face lifelong struggles with reading, exhibit numerous associated low-level sensory deficits including deficits in focal attention. Countering this, studies have shown that struggling readers outperform typical readers in some visual tasks that integrate distributed information across an expanse. Though such abilities would be expected to facilitate scene memory, prior investigations using the contextual cueing paradigm failed to find corresponding advantages in dyslexia. We suggest that these studies were confounded by task-dependent effects exaggerating known focal attention deficits in dyslexia, and that, if natural scenes were used as the context, advantages would emerge. Here, we investigate this hypothesis by comparing college students with histories of severe lifelong reading difficulties (SR) and typical readers (TR) in contexts that vary attention load. We find no differences in contextual-cueing when spatial contexts are letter-like objects, or when contexts are natural scenes. However, the SR group significantly outperforms the TR group when contexts are low-pass filtered natural scenes [F(3, 39) = 3.15, p<.05]. These findings suggest that perception or memory for low spatial frequency components in scenes is enhanced in dyslexia. These findings are important because they suggest strengths for spatial learning in a population otherwise impaired, carrying implications for the education and support of students who face challenges in school

Studio degli effetti dell&#8217;uso combinato di fasci terapeutici di particelle cariche e radiosensibilizzanti in cellule tumorali umane coltivate in vitro

Nell\u2019ambito delle terapie oncologiche \ue8 crescente l\u2019interesse per trattamenti che abbinino alle radiazioni l\u2019utilizzo di agenti chimici potenziali radiosensibilizzanti. L\u2019obiettivo di questo tipo di trattamenti \ue8 quello di ottenere un miglior controllo locale del tumore e di ridurre la probabilit\ue0 di formazione di metastasi. In letteratura sono stati pubblicati numerosi studi sull\u2019uso concomitante di fasci terapeutici di fotoni e diversi agenti chimici, ma attualmente ben pochi dati sono disponibili sull\u2019azione combinata di adroni e agenti chimici radiosensibilizzanti. In questo lavoro si descrivono i risultati di uno studio radiobiologico condotto su fasci terapeutici di fotoni e di protoni, ed alcuni dati preliminari relativi a fasci di ioni Carbonio, utilizzando cellule umane tumorali coltivate in vitro, trattate o meno, durante le 24 ore precedenti l\u2019irraggiamento, con il chemioterapico Epothilone B, un agente microtubulo-stabilizzante. I principali obiettivi dello studio sono: - determinare l\u2019efficacia dei fasci di adroni rispetto ai fotoni, per le linee cellulari studiate ( RBE) - studiare la modalit\ue0 di interazione delle diverse radiazioni con Epothilone B per valutare se sia additiva o sinergica. Sono stati utilizzati i fasci terapeutici di adroni di CNAO (Pavia) e di fotoni presso l\u2019Istituto Tumori di Milano. Lo studio \ue8 stato condotto su linee cellulari umane di glioblastoma multiforme (U251MG), adenocarcinoma polmonare a cellule non piccole (A549) e medulloblastoma pediatrico (DAOY). I principali effetti biologici studiati sono il mantenimento della capacit\ue0 proliferativa (sopravvivenza clonogenica), la crescita e l\u2019invasivit\ue0 cellulare. I risultati ottenuti hanno mostrato che: - l\u2019RBE dei protoni dipende fortemente dalla linea cellulare e, per glioblastoma multiforme e per adenocarcinoma polmonare, \ue8 risultata maggiore di 1.1, valore attualmente usato nella pratica clinica. - Il chemioterapico Epothilone B aumenta la citotossicit\ue0 dei fasci di protoni e di fotoni e l\u2019effetto del trattamento combinato \ue8 pi\uf9 che additivo

Performance of the QWIP Focal Plane Arrays for NASA's Landsat Data Continuity Mission

The focal plane assembly for the Thermal Infrared Sensor (TIRS) instrument on NASA's Landsat Data Continuity Mission (LDCM) consists of three 512 x 640 GaAs Quantum Well Infrared Photodetector (QWIP) arrays. The three arrays are precisely mounted and aligned on a silicon carrier substrate to provide a continuous viewing swath of 1850 pixels in two spectral bands defined by filters placed in close proximity to the detector surfaces. The QWIP arrays are hybridized to Indigo ISC9803 readout integrated circuits (ROICs). QWIP arrays were evaluated from four laboratories; QmagiQ, (Nashua, NH), Army Research Laboratory, (Adelphi, MD}, NASA/ Goddard Space Flight Center, (Greenbelt, MD) and Thales, (Palaiseau, France). All were found to be suitable. The final discriminating parameter was the spectral uniformity of individual pixels relative to each other. The performance of the QWIP arrays and the fully assembled, NASA flight-qualified, focal plane assembly will be reviewed. An overview of the focal plane assembly including the construction and test requirements of the focal plane will also be described

The Proton-Boron Reaction Increases the Radiobiological Effectiveness of Clinical Low- and High-Energy Proton Beams: Novel Experimental Evidence and Perspectives

Protontherapy is a rapidly expanding radiotherapy modality where accelerated proton beams are used to precisely deliver the dose to the tumor target but is generally considered ineffective against radioresistant tumors. Proton-Boron Capture Therapy (PBCT) is a novel approach aimed at enhancing proton biological effectiveness. PBCT exploits a nuclear fusion reaction between low-energy protons and 11B atoms, i.e. p+11B→ 3α (p-B), which is supposed to produce highly-DNA damaging α-particles exclusively across the tumor-conformed Spread-Out Bragg Peak (SOBP), without harming healthy tissues in the beam entrance channel. To confirm previous work on PBCT, here we report new in-vitro data obtained at the 62-MeV ocular melanoma-dedicated proton beamline of the INFN-Laboratori Nazionali del Sud (LNS), Catania, Italy. For the first time, we also tested PBCT at the 250-MeV proton beamline used for deep-seated cancers at the Centro Nazionale di Adroterapia Oncologica (CNAO), Pavia, Italy. We used Sodium Mercaptododecaborate (BSH) as 11B carrier, DU145 prostate cancer cells to assess cell killing and non-cancer epithelial breast MCF-10A cells for quantifying chromosome aberrations (CAs) by FISH painting and DNA repair pathway protein expression by western blotting. Cells were exposed at various depths along the two clinical SOBPs. Compared to exposure in the absence of boron, proton irradiation in the presence of BSH significantly reduced DU145 clonogenic survival and increased both frequency and complexity of CAs in MCF-10A cells at the mid- and distal SOBP positions, but not at the beam entrance. BSH-mediated enhancement of DNA damage response was also found at mid-SOBP. These results corroborate PBCT as a strategy to render protontherapy amenable towards radiotherapy-resilient tumor. If coupled with emerging proton FLASH radiotherapy modalities, PBCT could thus widen the protontherapy therapeutic index

Atypical Balance between Occipital and Fronto-Parietal Activation for Visual Shape Extraction in Dyslexia

Reading requires the extraction of letter shapes from a complex background of text, and an impairment in visual shape extraction would cause difficulty in reading. To investigate the neural mechanisms of visual shape extraction in dyslexia, we used functional magnetic resonance imaging (fMRI) to examine brain activation while adults with or without dyslexia responded to the change of an arrow’s direction in a complex, relative to a simple, visual background. In comparison to adults with typical reading ability, adults with dyslexia exhibited opposite patterns of atypical activation: decreased activation in occipital visual areas associated with visual perception, and increased activation in frontal and parietal regions associated with visual attention. These findings indicate that dyslexia involves atypical brain organization for fundamental processes of visual shape extraction even when reading is not involved. Overengagement in higher-order association cortices, required to compensate for underengagment in lower-order visual cortices, may result in competition for top-down attentional resources helpful for fluent reading.Ellison Medical FoundationMartin Richmond Memorial FundNational Institutes of Health (U.S.). (Grant UL1RR025758)National Institutes of Health (U.S.). (Grant F32EY014750-01)MIT Class of 1976 (Funds for Dyslexia Research

Encoding order and developmental dyslexia:a family of skills predicting different orthographic components

We investigated order encoding in developmental dyslexia using a task that presented nonalphanumeric visual characters either simultaneously or sequentially—to tap spatial and temporal order encoding, respectively—and asked participants to reproduce their order. Dyslexic participants performed poorly in the sequential condition, but normally in the simultaneous condition, except for positions most susceptible to interference. These results are novel in demonstrating a selective difficulty with temporal order encoding in a dyslexic group. We also tested the associations between our order reconstruction tasks and: (a) lexical learning and phonological tasks; and (b) different reading and spelling tasks. Correlations were extensive when the whole group of participants was considered together. When dyslexics and controls were considered separately, different patterns of association emerged between orthographic tasks on the one side and tasks tapping order encoding, phonological processing, and written learning on the other. These results indicate that different skills support different aspects of orthographic processing and are impaired to different degrees in individuals with dyslexia. Therefore, developmental dyslexia is not caused by a single impairment, but by a family of deficits loosely related to difficulties with order. Understanding the contribution of these different deficits will be crucial to deepen our understanding of this disorder