Reaching More Students: A Web-based Intelligent Tutoring System with support for Offline Access

ASSISTments is a web-based intelligent tutoring system that can provide students with immediate feedback when they are doing math homework. Until now, ASSISTments required internet access in order to do nightly homework. Without ASSISTments, students do their work on paper and are not told if they are correct or given help for wrong answers until the next morning at best. We\u27ve developed a component that supports \u27offline-mode\u27, enabling students without internet access at home to still receive immediate feedback on their responses. Students with laptops download their assignments at school, and then run ASSISTments at home in offline mode, utilizing the browser\u27s application cache and Web Storage API. To evaluate the benefit of having the offline feature, we ran a randomized controlled study that tests the effect of immediate feedback on student learning. Intuition would suggest that providing a student with tutoring and feedback immediately after they submit an answer would lead to better understanding of the material than having them wait until the next day. The results of the study confirmed our hypothesis, and validated the need for \u27offline mode.\u2

Pathogenesis of vestibular schwannoma in ring chromosome 22

<p>Abstract</p> <p>Background</p> <p>Ring chromosome 22 is a rare human constitutional cytogenetic abnormality. Clinical features of neurofibromatosis type 1 and 2 as well as different tumour types have been reported in patients with ring chromosome 22. The pathogenesis of these tumours is not always clear yet.</p> <p>Methods</p> <p>We report on a female patient with a ring chromosome 22 presenting with severe mental retardation, autistic behaviour, café-au-lait macules and facial dysmorphism. Peripheral blood lymphocytes were karyotyped and array CGH was performed on extracted DNA. At the age of 20 years she was diagnosed with a unilateral vestibular schwannoma. Tumour cells were analyzed by karyotyping, array CGH and <it>NF2 </it>mutation analysis.</p> <p>Results</p> <p>Karyotype on peripheral blood lymphocytes revealed a ring chromosome 22 in all analyzed cells. A 1 Mb array CGH experiment on peripheral blood DNA showed a deletion of 5 terminal clones on the long arm of chromosome 22. Genetic analysis of vestibular schwannoma tissue revealed loss of the ring chromosome 22 and a somatic second hit in the <it>NF2 </it>gene on the remaining chromosome 22.</p> <p>Conclusion</p> <p>We conclude that tumours can arise by the combination of loss of the ring chromosome and a pathogenic <it>NF2 </it>mutation on the remaining chromosome 22 in patients with ring chromosome 22. Our findings indicate that patients with a ring 22 should be monitored for NF2-related tumours starting in adolescence.</p

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Reactive oxygen species and male reproductive hormones

Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG) axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn could help in the management of male infertility

An Analysis of Aesthetic Refinements in 120 Secondary Cleft Rhinoplasties

Background Secondary cleft nose rhinoplasty remains a challenging procedure. Cartilage memory and scar contraction are problematic factors. The need for more detailed procedures for secondary reconstruction in this patient population has arisen. Contemporary refinements demonstrate a highly structured approach. We conducted a retrospective study evaluating the aesthetic results of cleft patients who underwent secondary rhinoplasty. Methods In a retrospective study, a photometric analysis of cleft patients operated in the period 2003-2011 was conducted. Reconstructive methods were documented. Pre- and postoperative photographs of cleft rhinoplasty patients were evaluated using a standardized protocol. Nostril width ratio, columellar angle, tip projection ratio, and nasolabial angle served as objective instruments. The Unilateral Cleft Lip Surgical Outcomes Evaluation score was chosen for external photometric rating and rated blindly by 2 external individual plastic surgeons as independent nonbiased reviewers. The interrater and intrarater reliabilities were calculated using the Cohen kappa coefficient (kappa). Results A total of 120 secondary rhinoplasties in 85 uni- and bilateral cleft patients could be included. Mean follow-up was 20 months. A total of 60 (71%) patients needed additional bone grafting (chin/pelvis), and 23 (27%) patients a LeFort I osteotomy. In one third of the secondary rhinoplasties, a medial and/or lateral osteotomy was performed (34%). In one fourth (24%), an external septoplasty was considered necessary. In 55% (47 patients) of the cases, a columellar strut was used. Excluding bone grafts, a total of 173 other grafts (mean of 2 grafts/patient) were applied. Postoperative measurements for nostril width ratio and columellar angle were statistically significant. A structured approach with contemporary refinements is described in detail. Intra- and interrater reliabilities for photometric assessment according to the Unilateral Cleft Lip Surgical Outcomes Evaluation score are shown. Conclusions A structured approach for secondary cleft rhinoplasty yields satisfying, reproducible, and stable results