73 research outputs found

    New renewably-sourced polyesters from limonene-derived monomers

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    The functionalisation of limonene has enabled the synthesis of two renewably-sourced monomers for the formation of terpene-derived polyesters. Three methods for the synthesis of the novel hydroxy-acid 6 are reported and their green-credentials scrutinised through comparison of their sustainability-metrics. Step-growth homo-polymerisation of 6 is demonstrated to yield a low molecular weight (2.6 kDa) novel polyester with 100% of its carbon content originating from the terpene starting material. The corresponding diol 2 is shown to act as a co-monomer with a renewable diacid. The resultant polyesters display impressive Mns of up to 30 kDa with Tgs between −6 and 24 °C. These materials have been shown to depolymerise under basic conditions for reclamation of the diol monomer 2

    Androgen receptor genotyping in a large Australasian cohort with androgen insensitivity syndrome; identification of four novel mutations

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    We genotyped the androgen receptor (AR) gene in 31 Australasian patients with androgen insensitivity syndrome (AIS). The entire coding region of AR was examined including analysis of polymorphic CAG and GGN repeats in all patients. AR defects were found in 66.7% (6/9) of patients with complete AIS (CAIS) and 13.6% (3/22) of patients with partial AIS (PAIS). A novel deletion (N858delG) leading to a premature stop codon was found in CAIS patient P1. CAIS patient P2 has a novel deletion (N2676delGAGT) resulting in a stop at codon 787. These mutations would result in inactivation of AR protein. A novel insertion of a cysteine residue in the first zinc finger of the AR DNA-binding domain (N2045_2047dupCTG) was found in CAIS patient P3. PAIS patient P4 has a novel amino acid substitution (Arg760Ser) in the AR ligand binding domain, which may impair ligand binding. Five patients were found to have previously reported AR mutations and no mutations were identified in the remaining patients

    Collaborative information seeking with ant colony ranking in real-time

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    In this paper we propose a new ranking algorithm based on Swarm Intelligence, more specifically on the Ant Colony Optimization technique, to improve search engines’ performances and reduce the information overload by exploiting users’ collective behavior. We designed an online evaluation involving end users to test our algorithm in a real-world scenario dealing with informational queries. The development of a fully working prototype – based on the Wikipedia search engine – demonstrated promising preliminary results

    Terpene polyacrylate TPA5 shows favorable molecular hydrodynamic properties as a potential bioinspired archaeological wood consolidant

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    There is currently a pressing need for the development of novel bioinspired consolidants for waterlogged, archaeological wood. Bioinspired materials possess many advantages, such as biocompatibility and sustainability, which makes them ideal to use in this capacity. Based on this, a polyhydroxylated monomer was synthesised from α-pinene, a sustainable terpene feedstock derived from pine trees, and used to prepare a low molar mass polymer TPA5 through free radical polymerisation. This polymer was extensively characterised by NMR spectroscopy (chemical composition) and molecular hydrodynamics, primarily using analytical ultracentrifugation reinforced by gel filtration chromatography and viscometry, in order to investigate whether it would be suitable for wood consolidation purposes. Sedimentation equilibrium indicated a weight average molar mass Mw of (4.3 ± 0.2) kDa, with minimal concentration dependence. Further analysis with MULTISIG revealed a broad distribution of molar masses and this heterogeneity was further confirmed by sedimentation velocity. Conformation analyses with the Perrin P and viscosity increment ν universal hydrodynamic parameters indicated that the polymer had an elongated shape, with both factors giving consistent results and a consensus axial ratio of ~ 4.5. These collective properties—hydrogen bonding potential enhanced by an elongated shape, together with a small injectable molar mass—suggest this polymer is worthy of further consideration as a potential consolidant

    Endocrinologic, neurologic, and visual morbidity after treatment for craniopharyngioma

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    Craniopharyngiomas are locally aggressive tumors which typically are focused in the sellar and suprasellar region near a number of critical neural and vascular structures mediating endocrinologic, behavioral, and visual functions. The present study aims to summarize and compare the published literature regarding morbidity resulting from treatment of craniopharyngioma. We performed a comprehensive search of the published English language literature to identify studies publishing outcome data of patients undergoing surgery for craniopharyngioma. Comparisons of the rates of endocrine, vascular, neurological, and visual complications were performed using Pearson’s chi-squared test, and covariates of interest were fitted into a multivariate logistic regression model. In our data set, 540 patients underwent surgical resection of their tumor. 138 patients received biopsy alone followed by some form of radiotherapy. Mean overall follow-up for all patients in these studies was 54 ± 1.8 months. The overall rate of new endocrinopathy for all patients undergoing surgical resection of their mass was 37% (95% CI = 33–41). Patients receiving GTR had over 2.5 times the rate of developing at least one endocrinopathy compared to patients receiving STR alone or STR + XRT (52 vs. 19 vs. 20%, χ2P < 0.00001). On multivariate analysis, GTR conferred a significant increase in the risk of endocrinopathy compared to STR + XRT (OR = 3.45, 95% CI = 2.05–5.81, P < 0.00001), after controlling for study size and the presence of significant hypothalamic involvement. There was a statistical trend towards worse visual outcomes in patients receiving XRT after STR compared to GTR or STR alone (GTR = 3.5% vs. STR 2.1% vs. STR + XRT 6.4%, P = 0.11). Given the difficulty in obtaining class 1 data regarding the treatment of this tumor, this study can serve as an estimate of expected outcomes for these patients, and guide decision making until these data are available

    The child of uncertain sex: 17 years of experience

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    Objective: To review the common clinical presentations, investigations and final diagnosis of children presenting with genital ambiguity. Methodology: Retrospective search of the Royal Children's Hospital, Brisbane, Australia, medical records and personal medical database of one of the authors (MJT) between 1982 and 1999. Results: Fifty-one children aged 0.1-;14 (mean 3.9) years were identified. Twenty-two cases had a 46XX karyotype, and commonly presented with an enlarged phallus (77.2%), urogenital sinus (63.6%) and labioscrotal fold(s) (40.9%). Congenital adrenal hyperplasia (CAH) was the most common final diagnosis (72.7%) . Twenty-nine cases of genital ambiguity had a 46XY karyotype and commonly presented with palpable gonad(s) (75.8%), undescended testes (51.7%), penoscrotal hypospadias (51.7%) and a small phallus (41.3%). Androgen insensitivity and gonadal dysgenesis were the commonest final diagnosis both occurring at a frequency of 17.2%. Conclusions: The results emphasize the importance of CAH as the most common diagnosis in 46XX cases presenting with ambiguous genitalia. Those with 46XY had a wider range of diagnoses. Despite thorough investigation, 23.5% had no definite final diagnosis made

    Acquired central diabetes insipidus in children: A 12 year Brisbane experience

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    Objective: To study the clinical, endocrine and radiological features and progress of children presenting with acquired diabetes insipidus (CDI). Methodology: Chart review of children presenting because of CDI to Brisbane paediatric endocrine clinics between 1987 and 1999. Results: Thirty-nine children (female/male ratio 21/18) aged 0.1-15.4 years (mean age 6.7 years) were identified. Aetiologies were head trauma or familial in eight cases (20.5%) each, central nervous system (CNS) tumours in five cases (12.8%), CNS malformations in four cases (10.2%), histiocytosis in three cases (7%) and hypoxia and infection in two cases (5.1%) each. Seven cases (17.9%) remain undiagnosed. Of the 32 (82%) cases with isolated anti-diuretic hormone deficiency at presentation, 24 cases (61.5%) experienced no further endocrine deficit. Additional endocrine deficits occurred mainly in the tumour or undiagnosed groups. On follow-up brain magnetic resonance imaging (MRI) scans in the seven undiagnosed cases, six patients bad mild or no change and one patient had marked improvement of MRI findings. These changes occurred 10-48 months (mean 18 months) after presentation. Conclusions: Children without an aetiological diagnosis for the uncommon condition of acquired CDI require careful follow-up. More intensive investigation at presentation (e.g. estimation of cerebrospinal fluid human chorionic gonadotrophin) promises to lessen the number of such cases. Pituitary stalk biopsies should be reserved for those patients with progressive MRI changes. If these changes do not occur early, our experience suggests that follow-up MRI scans may need to be performed only yearly

    How well are we doing? Metabolic control in patients with diabetes

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    Objective: To compare the present level of metabolic control in children and adolescents with insulin-dependent diabetes mellitus (IDDM) attending Brisbane paediatric diabetes clinics with published overseas data. Methodology: Blood HbA(1c) concentrations, population characteristics, current treatment practices and short-term complications were recorded in all patients, aged 19 years and under, attending the diabetes clinics of the two Brisbane Children's Hospitals or the private practice of one of the authors (MJT) in the first quarter of 1998. Results: Two hundred and sixty-eight patients were assessed (M/F 142/126). Ages ranged from 1 to 19 years (mean 11.2 years); duration of IDDM was 0-16 years (mean 4.4 years); and 141 (53%) were pubertal. Of those aged less than 13 years, only 4% had more than two injections daily. Insulin doses (U/kg/day) rose with increasing age. Larger doses were required in regimens involving more than two injections per day than those involving one to two injections per day. Ketoacidosis or severe hypoglycaemia in the last 3 months were reported in eight (2.7%) and 17 (6.3%) of patients, respectively. Mean HbA(1c) (+/- SD) was 8.6 +/- 1.4% (range 5.2-14.0%), with 33% of children having a HbA(1c) concentration < 8%. HbA(1c) concentrations were significantly related (P < 0.05) to insulin dose and to duration of diabetes, but not to severe hypoglycaemia, ketoacidosis, age, frequency of injections, or number of clinic visits per year. Mean HbA(1c) concentration was significantly higher (P < 0.05) in those children in puberty (8.7 +/- 1.5%) than in those not in puberty (8.5 +/- 1.2%). Conclusions: Only 33% of patients had a HbA(1c) concentration less than 8% and 6.3% had a severe hypoglycaemic episode in the 3 months. These results are similar to published overseas data

    SponTaneous Respiration using IntraVEnous anaesthesia and Hi-flow nasal oxygen (STRIVE Hi) maintains oxygenation and airway patency during management of the obstructed airway: an observational study

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    Background. High-flow nasal oxygen (HFNO) has been shown to benefit oxygenation, ventilation and upper airway patency in a range of clinical scenarios, however its use in spontaneously breathing patients during general anaesthesia has not been described. Spontaneous respiration using i.v. anaesthesia is the primary technique used at our institution for tubeless airway surgery. We hypothesized that the addition of HFNO would increase our margin of safety, particularly during management of an obstructed airway. Methods. A retrospective observational study was conducted using a SponTaneous Respiration using IntraVEnous anaesthesia and High-flow nasal oxygen (STRIVE Hi) technique to manage 30 adult patients undergoing elective laryngotracheal surgery. Results. Twenty-six patients (87%) presented with significant airway and/or respiratory compromise (16 were stridulous, 10 were dyspnoeic). No episodes of apnoea or complete airway obstruction occurred during the induction of anaesthesia using STRIVE Hi. The median [IQR (range)] lowest oxygen saturation during the induction period was 100 [99-100 (97-100)] %. The median [IQR (range)] overall duration of spontaneous ventilation was 44 [40-49.5 (18-100)] min. The median [IQR (range)] end-tidal carbon dioxide (ETCO2) level at the end of the spontaneous ventilation period was 6.8 [6.4-7.1 (4.8-8.9)] kPa. The mean rate of increase in ETCO2 was 0.03 kPa min1. Conclusions. STRIVE Hi succeeded in preserving adequate oxygen saturation, end-tidal carbon dioxide and airway patency. We suggest that the upper and lower airway benefits attributed to HFNO, are ideally suited to a spontaneous respiration induction, increasing its margin of safety. STRIVE Hi is a modern alternative to the traditional inhalation induction
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