Age-related macular degeneration

Age-related Macular Degeneration (AMD) is a degenerative condition affecting the macular area of the retina. Those affected are usually over the age of 50 years and AMD is the leading cause of blindness over this age in the Western world. It results in distortion or loss of central sharp vision making it difficult to view the object of interest and to carry out close work, to read and write, to recognise faces and to drive although enough peripheral vision remains to allow other activities of daily life.peer-reviewe

Primary CNS lymphoma with intravitreal metastasis : using vitreous cavity samples to monitor response to therapy

A fifty-eight year old male patient presented to the ophthalmic department with a 3 day history of reduced visual acuity, blurred vision and floaters, associated with recent lethargy, headaches and behavioural changes. Fundal examination revealed a bilateral vitritis. Steroid therapy was started. MRI of the brain revealed multiple hypodense and hyperdense lesions. Vitrectomy was performed in view of the poor response to steroids. A biopsy showed non-hodgkin B-Cell lymphoma. The patient was started on intravenous Methotrexate and Cytarabine. Repeat vitreous cavity biopsies were performed in order to assess response to therapy. All biopsies to date have revealed evidence of on-going lymphoma.peer-reviewe

A critical and comparative analysis of the expression "ordinarily resident" as a criterion for determining the place of residence of an individual in the context of income tax legislation in South Africa and certain other juristictions.

Master of Laws in Law and Management Studies. University of KwaZulu-Natal, Pietermaritzburg, 2016.The nexus between a natural person’s income and their liability to tax in South Africa on their income, regardless of the location of its source, subject to statutory relief and international agreements, is the individual’s status as an income tax resident in South Africa. The criterion for determining the place of residence of an individual in the context of income tax can be uncertain and difficult to determine due to the case law approach imposed by the definition of the term ‘resident’ in the Income Tax Act. Through an analysis of the legislation, case law and guidelines, primarily in South Africa and the United Kingdom, the dissertation queries whether the current legislation and case law in South Africa is adequate to deal with the determination of the place of residence of an individual in the context of income tax legislation in South Africa and if a new statutory definition of residence should be considered

The relationship between the MCMI-III and the MMPI-2 in a chronic pain population.

The purpose of the present study was to study the relationship of MCMI-III clinical scales with MMPI-2 clusters in a chronic pain population. Data was obtained through assessment data (N = 242) from the Dallas Spinal Rehabilitation Center (DSRC), that included MMPI-2 and MCMI-III, as well as pre-and post-assessment information (n = 21) and follow-up questionnaires (n = 19). Subjects' age ranged from 18 to 64. Each patient had a primary diagnosis related to a back and/or a cervical injury, a chronic pain diagnosis, and often medical prescription dependency and/or addition. Each has experienced back pain in the lumbar region (L1 to L5) or cervical region (C1 to C7) for an average of 32 months. Patients with thoracic (mid-spine) and carpal tunnel pain were excluded from this study. A multivariate cluster analysis procedure was performed that yielded 3 homogeneous female MMPI-2 clusters and 4 MMPI-2 homogeneous male clusters. Seven multiple regression analyses were performed to determine which MCMI-III clinical scales predicted cluster membership in the MMPI-2 clusters. Results indicated that MCMI-III clinical scales "7" Compulsive, "X" Validity and "C" Borderline were predictors for membership in the male MMPI-2 clusters. Membership in the female MMPI-2 clusters were predicted by MCMI-III clinical scales "4" Histrionic, "T" Drug Dependence and "2A" Avoidant. Nineteen pre-and post-MCMI-IIIs were analyzed for change after participants completed the six-week pain management program. Paired-sample t-tests were performed on these data and revealed that significant change was noted on 10 MCMI-III clinical scales. Follow-up data questionnaires were available on these same individuals. Results from a correlation analysis indicated that patients who reported having supportive relationships with their spouse and family and a secure source of income report better quality of sleep, better mood, are able to relax and are believe that they are able to manage their pain. Participants who were able to relax and remain calm report better quality of sleep, exercise frequently, report better quality of mood and believe that they will return to work soon. Findings from this study suggest that rather than using the MCMI-III as a diagnostic tool, a more efficient use of this instrument would be to understand maladaptive coping styles that may be present under stressful situations. This study's findings suggest that pain treatment program staff could utilize follow up information, as well as diagnostic information about coping strategies that might appear under stress, to shape interventions. Future research might focus on investigation of factors that predict both improvement and program failure, especially those present at initial intake

CBS domains form energy-sensing modules whose binding of adenosine ligands is disrupted by disease mutations

CBS domains are defined as sequence motifs that occur in several different proteins in all kingdoms of life. Although thought to be regulatory, their exact functions have been unknown. However, their importance was underlined by findings that mutations in conserved residues within them cause a variety of human hereditary diseases, including (with the gene mutated in parentheses): Wolff-Parkinson-White syndrome (γ2 subunit of AMP-activated protein kinase); retinitis pigmentosa (IMP dehydrogenase-1); congenital myotonia, idiopathic generalized epilepsy, hypercalciuric nephrolithiasis, and classic Bartter syndrome (CLC chloride channel family members); and homocystinuria (cystathionine β-synthase). AMP-activated protein kinase is a sensor of cellular energy status that is activated by AMP and inhibited by ATP, but the location of the regulatory nucleotide-binding sites (which are prime targets for drugs to treat obesity and diabetes) was not characterized. We now show that tandem pairs of CBS domains from AMP-activated protein kinase, IMP dehydrogenase-2, the chloride channel CLC2, and cystathionine β-synthase bind AMP, ATP, or S-adenosyl methionine,while mutations that cause hereditary diseases impair this binding. This shows that tandem pairs of CBS domains act, in most cases, as sensors of cellular energy status and, as such, represent a newly identified class of binding domain for adenosine derivatives

Quench Risk Increase With Radiation Damage

Superconducting magnets are often proposed to confine plasma in fusion reactors. Superconducting material enables the magnets to carry current densities that would melt materials with non-zero resistance. Quench occurs when superconductivity is lost and the current starts to generate heat. Unless prevented with a fast enough control system, the heat generated during a quench can cause catastrophic damage to the coils. This work describes a less-studied heating mechanism that increases the likelihood and aggressiveness of fusion magnet quenches. Defects accumulate in the magnet structural material under irradiation by the fusion process. The defects store energy in the material and change thermal and normal state electrical properties. Wigner energy is released when defects anneal. After a 0.9 mDPA neutron irradiation, a 10 K disturbance from 20 K is predicted to release enough energy to result in a final temperature of 40 K. Irradiation damage also reduces the quench time constant by increasing normal state resistivity and thus Ohmic heating. The continuous operation of a fusion reactor produces an increasingly unstable thermodynamic system in superconducting magnets by changing electrical and thermal properties with irradiation damage. The temperature margin between operation and quench runaway reduces with irradiation. The next steps are to include these observations in quench models and validate the predictions experimentally. Implications of this work is felt by all fusion powerplant projects planning to leverage superconducting magnets. Designs will recognize this risk with more stringent specifications on quench control systems and maximum duration of coil operation at cryogenic temperature between periodic releases of Wigner energy to avoid catastrophic quench failures.Comment: 6 pages, 9 figures, 1 table. Work presented at Symposium on Fusion Engineering 2023 in Oxford on July 13th. The work is a hot topic and has been shared publicly. The work has significant implications for the design of some private machines. After publishing on Arxiv the work will be shared for peer review. The work will be submitted for a IEEE Transactions on plasma science early Septembe

A quasi classical approach to fully differential ionization cross sections

A classical approximation to time dependent quantum mechanical scattering in the M\o{}ller formalism is presented. Numerically, our approach is similar to a standard Classical-Trajectory-Monte-Carlo calculation. Conceptually, however, our formulation allows one to release the restriction to stationary initial distributions. This is achieved by a classical forward-backward propagation technique. As a first application and for comparison with experiment we present fully differential cross sections for electron impact ionization of atomic hydrogen in the Erhardt geometry.Comment: 6 pages, 2 figure

In Helicobacter pylori auto-inducer-2, but not LuxS/MccAB catalysed reverse transsulphuration, regulates motility through modulation of flagellar gene transcription.

BACKGROUND: LuxS may function as a metabolic enzyme or as the synthase of a quorum sensing signalling molecule, auto-inducer-2 (AI-2); hence, the mechanism underlying phenotypic changes upon luxS inactivation is not always clear. In Helicobacter pylori, we have recently shown that, rather than functioning in recycling methionine as in most bacteria, LuxS (along with newly-characterised MccA and MccB), synthesises cysteine via reverse transsulphuration. In this study, we investigated whether and how LuxS controls motility of H. pylori, specifically if it has its effects via luxS-required cysteine metabolism or via AI-2 synthesis only. RESULTS: We report that disruption of luxS renders H. pylori non-motile in soft agar and by microscopy, whereas disruption of mccAHp or mccBHp (other genes in the cysteine provision pathway) does not, implying that the lost phenotype is not due to disrupted cysteine provision. The motility defect of the DeltaluxSHp mutant was complemented genetically by luxSHp and also by addition of in vitro synthesised AI-2 or 4, 5-dihydroxy-2, 3-pentanedione (DPD, the precursor of AI-2). In contrast, exogenously added cysteine could not restore motility to the DeltaluxSHp mutant, confirming that AI-2 synthesis, but not the metabolic effect of LuxS was important. Microscopy showed reduced number and length of flagella in the DeltaluxSHp mutant. Immunoblotting identified decreased levels of FlaA and FlgE but not FlaB in the DeltaluxSHp mutant, and RT-PCR showed that the expression of flaA, flgE, motA, motB, flhA and fliI but not flaB was reduced. Addition of DPD but not cysteine to the DeltaluxSHp mutant restored flagellar gene transcription, and the number and length of flagella. CONCLUSIONS: Our data show that as well as being a metabolic enzyme, H. pylori LuxS has an alternative role in regulation of motility by modulating flagellar transcripts and flagellar biosynthesis through production of the signalling molecule AI-2

High-Resolution Image Reconstruction from a Sequence of Rotated and Translated Frames and its Application to an Infrared Imaging System

Some imaging systems employ detector arrays that are not sufficiently dense to meet the Nyquist criterion during image acquisition. This is particularly true for many staring infrared imagers. Thus, the full resolution afforded by the optics is not being realized in such a system. This paper presents a technique for estimating a high-resolution image, with reduced aliasing, from a sequence of undersampled rotated and translationally shifted frames. Such an image sequence can be obtained if an imager is mounted on a moving platform, such as an aircraft. Several approaches to this type of problem have been proposed in the literature. Here we extend some of this previous work. In particular, we define an observation model that incorporates knowledge of the optical system and detector array. The high-resolution image estimate is formed by minimizing a regularized cost function based on the observation model. We show that with the proper choice of a tuning parameter, our algorithm exhibits robustness in the presence of noise. We consider both gradient descent and conjugate-gradient optimization procedures to minimize the cost function. Detailed experimental results are provided to illustrate the performance of the proposed algorithm using digital video from an infrared imager