Diazanaphthalenes: A 13C NMR investigation on the site of protonation and pKa values

The pH dependence of the 13C chemical shifts (δ) of the diazanaphthalenes has been recorded. From this dependence the pKa values have been determined using the Henderson-Hasselbach equation. The change in 13C chemical shifts under the influence of nitrogen protonation (Δδ) has been predicted using the Δδ values of quinoline and isoquinoline. The correlation between observed and expected Δδ values of the symmetric diazanaphthalenes is very good. Assuming these changes in chemical shifts to be of general validity, the site of protonation in the asymmetric diazanaphthalenes has been determined by comparison of the expected Δδ values for α- and ß-nitrogen protonation with the observed ones. The site of protonation for 1,6- and 1,7-naphthyridine is the ß-nitrogen atom, whereas for cinnoline both monoprotonated species are present in a significant amount

Molecular dynamics study of dislocation nucleation from a crack tip

We have performed a systematic molecular dynamics study of the competition between crack growth and dislocation emission from a crack tip. Two types of boundary conditions are adopted: either planar extension or boundary displacements according to the anisotropic mode-I asymptotic continuum solution. The effects of temperature, loading rate, crystal orientation, sharpness of the crack tip, atomic potential, and system size are investigated. Depending on the crystal orientation, dislocation nucleation can be driven either by the strain or by concerted fluctuations at the crack tip. In the latter case, crystal orientation and temperature have the largest influence on the process of dislocation nucleation

The local invariant factors of a product of holomorphic matrix functions: The order 4 case

Let {Mathematical expression}, resp. {Mathematical expression} be the (given) invariant factors of the square matrices A, resp. B of order n over the ring of germs of holomorphic functions in 0 such that det A(λ)B(λ)≠0, λ≠0. A description of all possible invariant factors {Mathematical expression} of the product C=AB is given in the following cases: (i)β1 (or α1)≤2; (ii)β3 = 0 (α3= 0); (iii) α1-α2, β1βm≤1, α2+1-βm+1-0. These results, which hold for arbitrary n, are complemented with a few results leading to the description of all possible exponents γ1,γ2,γ3,γ4 for arbitrary α1,α2,α3,α4 β1,β2,β3,β4 in the case where the order n≤4

The neuropsychological profiles of learners with Asperger Syndrome

A qualitative case study research design is used to investigate the results of a neuropsychological test battery, collated and used with four individual cases. A literature study consisting of research with respect to AS as well as neuropsychological assessments provides the theoretical framework from which existing theory is tested and expanded on. The cases are analysed individually and then by cross case analysis to ascertain any patterns of strength and weaknesses which could result in a "typical" profile of a learner with AS. Findings conclude confusions with respect to diagnostic criteria for AS and a distinction of DSM-IV-TR criteria is used. The neuropsychological test battery includes questionnaires (personal history, Gilliam Asperger's disorder scale, Conners' parent and teacher questionnaire, Dunn's sensory profile) interviews (parents, teachers), observations (classroom and playground) and formal testing (intelligence, motor functions, academic achievement, theory of mind and executive functions). Findings from the literature show similarities between AS children and children with non verbal learning disabilities. Evidence of AS differing from individuals with high functioning autism is conclusive in all previous research using theory of mind tests. Evidence from the literature shows many children had been given another diagnosis, typically ADHD, before being given the diagnosis of AS. Additional disorders such as anxiety and depression were also given. AS children had consistent difficulties with social interaction. A typical neuropsychological profile of AS is not identified, but rather a "personality type" that is dominated by anxiety and individual "quirks" of personality which affects responses to the formal test battery - thereby influencing the scores obtained. Two of the cases presented with an academic profile similar to that of a non verbal learning disability and one presented with similarities with a semantic pragmatic disorder. The thesis concludes with a proposed differentiating model of behavioural, communication and learning disorders in which AS is defined in terms of that originally described by Hans Asperger himself, and specifically treated within the education environment.Educational StudiesD.Ed. (Psychology of Education

The effects of a structured teaching method on mathematics anxiety and achievement of grade eight learners

The hypothesis that a structured, sequenced, approach to mathematics learning, based on the application of learnt facts, decreases mathematics anxiety and increases mathematics achievement is tested. A literature study and an empirical investigation were conducted with respect to the relationships between maths anxiety, maths achievement and teaching methods. A qualitative research design which focussed on the cross-case analysis of different case studies was used. The qualitative case study involves multiple methods such as interviews, observations and a pretest, posttest design. It analyses and compares the effects of the Kuman method, used as the intervention programme, on maths anxiety and maths achievement of an experimental group and a control group. The results of this research indicate that learners on the intervention programme who showed a decrease in anxiety, showed an increase in achievement. This has implications for the teaching methods used in South Africa.Teacher EducationM. Ed. (Specialisation in Guidance and Counselling

Breaking the silence of the 500-year-old smiling garden of everlasting flowers: The En Tibi book herbarium

We reveal the enigmatic origin of one of the earliest surviving botanical collections. The 16th-century Italian En Tibi herbarium is a large, luxurious book with c. 500 dried plants, made in the Renaissance scholarly circles that developed botany as a distinct discipline. Its Latin inscription, translated as “Here for you a smiling garden of everlasting flowers”, suggests that this herbarium was a gift for a patron of the emerging botanical science. We follow an integrative approach that includes a botanical similarity estimation of the En Tibi with contemporary herbaria (Aldrovandi, Cesalpino, “Cibo”, Merini, Estense) and analysis of the book’s watermark, paper, binding, handwriting, Latin inscription and the morphology and DNA of hairs mounted under specimens. Rejecting the previous origin hypothesis (Ferrara, 1542–1544), we show that the En Tibi was made in Bologna around 1558. We attribute the En Tibi herbarium to Francesco Petrollini, a neglected 16th-century botanist, to whom also belongs, as clarified herein, the controversial “Erbario Cibo” kept in Rome. The En Tibi was probably a work on commission for Petrollini, who provided the plant material for the book. Other people were apparently involved in the compilation and offering of this precious gift to a yet unknown person, possibly the Habsburg Emperor Ferdinand I. The En Tibi herbarium is a Renaissance masterpiece of art and science, representing the quest for truth in herbal medicine and botany. Our multidisciplinary approach can serve as a guideline for deciphering other anonymous herbaria, kept safely “hidden” in treasure rooms of universities, libraries and museums

Breaking the silence of the 500-year-old smiling garden of everlasting flowers: The En Tibi book herbarium

We reveal the enigmatic origin of one of the earliest surviving botanical collections. The 16th-century Italian En Tibi herbarium is a large, luxurious book with c. 500 dried plants, made in the Renaissance scholarly circles that developed botany as a distinct discipline. Its Latin inscription, translated as “Here for you a smiling garden of everlasting flowers”, suggests that this herbarium was a gift for a patron of the emerging botanical science. We follow an integrative approach that includes a botanical similarity estimation of the En Tibi with contemporary herbaria (Aldrovandi, Cesalpino, “Cibo”, Merini, Estense) and analysis of the book’s watermark, paper, binding, handwriting, Latin inscription and the morphology and DNA of hairs mounted under specimens. Rejecting the previous origin hypothesis (Ferrara, 1542–1544), we show that the En Tibi was made in Bologna around 1558. We attribute the En Tibi herbarium to Francesco Petrollini, a neglected 16th-century botanist, to whom also belongs, as clarified herein, the controversial “Erbario Cibo” kept in Rome. The En Tibi was probably a work on commission for Petrollini, who provided the plant material for the book. Other people were apparently involved in the compilation and offering of this precious gift to a yet unknown person, possibly the Habsburg Emperor Ferdinand I. The En Tibi herbarium is a Renaissance masterpiece of art and science, representing the quest for truth in herbal medicine and botany. Our multidisciplinary approach can serve as a guideline for deciphering other anonymous herbaria, kept safely “hidden” in treasure rooms of universities, libraries and museums

Successful Reduction of Creatine Kinase and Myoglobin Levels in Severe Rhabdomyolysis Using Extracorporeal Blood Purification (CytoSorb®)

Rhabdomyolysis, if severe, can lead to acute kidney injury (AKI). Myoglobin is an iron and oxygen-binding protein that is freely filtered by the glomerulus. Precipitation of myoglobin in the nephrons' distal parts is responsible for tubular damage with AKI as a consequence. Extracorporeal clearance of myoglobin is conventionally attempted by the use of continuous renal replacement therapy (CRRT) with high cut-off dialysis membranes to limit the extent of the damage. We describe a case of a 56-year-old man with traumatic crush injury and a persistent source of muscle ischaemia unresponsive to high dose CRRT with EMiC-2 filter. Due to therapy failure, he was subsequently treated with the addition of a haemoadsorber (CytoSorb®) to the circuit. This reduced myoglobin and creatine kinase