Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 154
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Nature ; 620(7976): 977-981, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37648759

RESUMO

Atomic defects in the solid state are a key component of quantum repeater networks for long-distance quantum communication1. Recently, there has been significant interest in rare earth ions2-4, in particular Er3+ for its telecom band optical transition5-7 that allows long-distance transmission in optical fibres. However, the development of repeater nodes based on rare earth ions has been hampered by optical spectral diffusion, precluding indistinguishable single-photon generation. Here, we implant Er3+ into CaWO4, a material that combines a non-polar site symmetry, low decoherence from nuclear spins8 and is free of background rare earth ions, to realize significantly reduced optical spectral diffusion. For shallow implanted ions coupled to nanophotonic cavities with large Purcell factor, we observe single-scan optical linewidths of 150 kHz and long-term spectral diffusion of 63 kHz, both close to the Purcell-enhanced radiative linewidth of 21 kHz. This enables the observation of Hong-Ou-Mandel interference9 between successively emitted photons with a visibility of V = 80(4)%, measured after a 36 km delay line. We also observe spin relaxation times T1,s = 3.7 s and T2,s > 200 µs, with the latter limited by paramagnetic impurities in the crystal instead of nuclear spins. This represents a notable step towards the construction of telecom band quantum repeater networks with single Er3+ ions.

2.
Phys Rev Lett ; 130(16): 166902, 2023 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-37154648

RESUMO

Neutral silicon vacancy centers (SiV^{0}) in diamond are promising candidates for quantum applications; however, stabilizing SiV^{0} requires high-purity, boron-doped diamond, which is not a readily available material. Here, we demonstrate an alternative approach via chemical control of the diamond surface. We use low-damage chemical processing and annealing in a hydrogen environment to realize reversible and highly stable charge state tuning in undoped diamond. The resulting SiV^{0} centers display optically detected magnetic resonance and bulklike optical properties. Controlling the charge state tuning via surface termination offers a route for scalable technologies based on SiV^{0} centers, as well as charge state engineering of other defects.

3.
Int J Eat Disord ; 56(8): 1661-1666, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37134198

RESUMO

OBJECTIVE: A comparative study to describe the increase in medical admissions of children and adolescents with anorexia nervosa (AN) in Western Australia in 2019 (pre-pandemic) and 2020 (peri-pandemic). METHOD: Patient demographics, physiological parameters, length of stay, time to assessment by the Eating Disorder Service (EDS), and commencement of specialist eating disorder (ED) outpatient treatment was collected for adolescents admitted with AN between 1st January 2019 and 31st December 2020. RESULTS: The number of admissions doubled from 126 in 2019 to 268 in 2020. The number of children admitted increased by 52%. The median length of hospital stay was shorter in 2020 (12 vs. 17 days; p < .001), but the 28-day readmission rate was greater (39.9% vs. 22.2%; p < .001). At the time of hospital discharge in 2020, only 60% of patients were able to step-down into specialist ED outpatient treatment, compared to 93% in 2019. The mean number of admissions per child before completing EDS assessment increased significantly in 2020 (2.75 vs. 0, p < .001). DISCUSSION: Shorter inpatient stays and delays in the commencement of specialist ED outpatient treatment may have contributed to the increased readmission rate seen in 2020. PUBLIC SIGNIFICANCE: This research is important as it explores the reasons for increased medical presentations and admissions of youth with AN during the COVID-19 pandemic in Western Australia. We hope that our lessons learned may be helpful to others trying to balance similar clinical workloads.


Assuntos
Anorexia Nervosa , COVID-19 , Adolescente , Criança , Humanos , Anorexia Nervosa/epidemiologia , Anorexia Nervosa/terapia , Pandemias , Austrália Ocidental/epidemiologia , COVID-19/epidemiologia , Hospitalização , Estudos Retrospectivos
4.
BMC Pediatr ; 23(1): 335, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37393229

RESUMO

BACKGROUND: Despite advances in neonatal intensive care, babies admitted to Neonatal Intensive Care Units (NICU) suffer from adverse outcomes. We aim to describe the longer-term respiratory infectious morbidity of infants discharged from NICU using state-wide population-based linked data in Western Australia. STUDY DESIGN: We used probabilistically linked population-based administrative data to analyse respiratory infection morbidity in a cohort of 23,784 infants admitted to the sole tertiary NICU, born 2002-2013 with follow up to 2015. We analysed incidence rates of secondary care episodes (emergency department presentations and hospitalisations) by acute respiratory infection (ARI) diagnosis, age, gestational age and presence of chronic lung disease (CLD). Poisson regression was used to investigate the differences in rates of ARI hospital admission between gestational age groups and those with CLD, after adjusting for age at hospital admission. RESULTS: From 177,367 child-years at risk (i.e., time that a child could experience an ARI outcome), the overall ARI hospitalisation rate for infants and children aged 0-8 years was 71.4/1000 (95% confidence interval, CI: 70.1, 72.6), with the highest rates in infants aged 0-5 months (242.9/1000). For ARI presentations to emergency departments, equivalent rates were 114/1000 (95% CI: 112.4, 115.5) and 337.6/1000, respectively. Bronchiolitis was the most common diagnosis among both types of secondary care, followed by upper respiratory tract infections. Extremely preterm infants (< 28 weeks gestation at birth) were 6.5 (95% CI: 6.0, 7.0) times more likely and those with CLD were 5.0 (95% CI: 4.7, 5.4) times more likely to be subsequently admitted for ARI than those in NICU who were not preterm or had CLD after adjusting for age at hospital admission. CONCLUSIONS: There is an ongoing burden of ARI in children who graduate from the NICU, especially those born extremely preterm, that persists into early childhood. Early life interventions to prevent respiratory infections in these children and understanding the lifelong impact of early ARI on later lung health are urgent priorities.


Assuntos
Unidades de Terapia Intensiva Neonatal , Terapia Intensiva Neonatal , Recém-Nascido , Humanos , Pré-Escolar , Lactente , Estudos de Coortes , Alta do Paciente , Lactente Extremamente Prematuro
5.
BMC Biol ; 20(1): 26, 2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-35073910

RESUMO

BACKGROUND: The evolution of the brain and its major neuropils in Panarthropoda (comprising Arthropoda, Tardigrada and Onychophora) remains enigmatic. As one of the closest relatives of arthropods, onychophorans are regarded as indispensable for a broad understanding of the evolution of panarthropod organ systems, including the brain, whose anatomical and functional organisation is often used to gain insights into evolutionary relations. However, while numerous recent studies have clarified the organisation of many arthropod nervous systems, a detailed investigation of the onychophoran brain with current state-of-the-art approaches is lacking, and further inconsistencies in nomenclature and interpretation hamper its understanding. To clarify the origins and homology of cerebral structures across panarthropods, we analysed the brain architecture in the onychophoran Euperipatoides rowelli by combining X-ray micro-computed tomography, histology, immunohistochemistry, confocal microscopy, and three-dimensional reconstruction. RESULTS: Here, we use this detailed information to generate a consistent glossary for neuroanatomical studies of Onychophora. In addition, we report novel cerebral structures, provide novel details on previously known brain areas, and characterise further structures and neuropils in order to improve the reproducibility of neuroanatomical observations. Our findings support homology of mushroom bodies and central bodies in onychophorans and arthropods. Their antennal nerve cords and olfactory lobes most likely evolved independently. In contrast to previous reports, we found no evidence for second-order visual neuropils, or a frontal ganglion in the velvet worm brain. CONCLUSION: We imaged the velvet worm nervous system at an unprecedented level of detail and compiled a comprehensive glossary of known and previously uncharacterised neuroanatomical structures to provide an in-depth characterisation of the onychophoran brain architecture. We expect that our data will improve the reproducibility and comparability of future neuroanatomical studies.


Assuntos
Artrópodes , Animais , Encéfalo , Sistema Nervoso , Reprodutibilidade dos Testes , Microtomografia por Raio-X
6.
J Paediatr Child Health ; 58(10): 1816-1823, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35819302

RESUMO

AIM: This study aimed to assess the effect of iron deficiency on parent-reported changes in quality of life (QOL) among children receiving an adenotonsillectomy for paediatric obstructive sleep apnoea (OSA). METHODS: This was a retrospective review study that recruited children under 16 years of age undergoing an adenotonsillectomy, adenoidectomy, or tonsillectomy for clinically diagnosed paediatric OSA between June 2020 and January 2021 inclusive, in Western Australia. The main outcome measures for this study were changes in QOL by age group and iron status, defined by an absolute change of more than 3 points on OSA-18 survey domains. RESULTS: About 249 participants had iron studies performed on perioperative blood samples drawn at operation and completed both pre-operative and post-operative OSA-18 QOL questionnaires at initial consultation and 8-12 weeks post-surgery, respectively. 41.8% were iron deficient, 53.8% were borderline iron deficient and 4.4% had normal iron levels. Following surgery, a decrease was observed for all OSA-18 score domains in post-operation scores compared to pre-operation scores in both iron-deficient and borderline iron-deficient cohorts. 'Daytime Problems' in the <2 years group, within the iron-deficient cohort, was the only domain that found to be non-superior (i.e. 'not better') following surgery. CONCLUSIONS: Following adenotonsillectomy, patients with paediatric OSA reported significant improvements in QOL regardless of their iron status. Those undergoing an adenotonsillectomy for paediatric OSA had a high prevalence of iron deficiency at operation, especially those under 6 years of age.


Assuntos
Deficiências de Ferro , Apneia Obstrutiva do Sono , Tonsilectomia , Adenoidectomia , Criança , Humanos , Ferro , Polissonografia , Qualidade de Vida , Apneia Obstrutiva do Sono/epidemiologia , Apneia Obstrutiva do Sono/cirurgia
7.
J Paediatr Child Health ; 58(1): 97-103, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34352136

RESUMO

AIM: To determine the frequency of protracted bacterial bronchitis (PBB) in children referred to tertiary care with chronic cough and describe management prior to referral. METHODS: A retrospective cohort study of all new patients with a history of ≥4 weeks of cough seen at the only tertiary paediatric outpatient respiratory service in Western Australia between July 2018 and June 2019. Medical records were reviewed until a final diagnosis was documented or otherwise for a period of 18 months. RESULTS: PBB was the most common cause and comprised 37.9% of all children referred to tertiary respiratory care with chronic cough. In children with PBB, the median cough duration at the time of first specialist review was 5.1 months (IQR 2.1-12.0 months). The most common referral source of PBB was primary practice (40.9%) and the most common working diagnosis pre-referral was asthma (15.9%). Seventy-eight percent of children with PBB had an ongoing cough at their first respiratory review, and of these, only 13.5% had been prescribed 4 weeks of antibiotics prior to their respiratory review. Asthma treatment had been prescribed for 34.0% of children with PBB. CONCLUSION: PBB is the most common cause of chronic cough in children referred to tertiary respiratory care and is frequently misdiagnosed and undertreated pre-referral. There is a need to facilitate diagnosis and optimal management of PBB in primary care, which could result in earlier symptom resolution and potentially limit disease progression to bronchiectasis.


Assuntos
Infecções Bacterianas , Bronquiectasia , Bronquite , Bronquite/diagnóstico , Bronquite/tratamento farmacológico , Bronquite/epidemiologia , Criança , Doença Crônica , Tosse/diagnóstico , Tosse/etiologia , Tosse/terapia , Humanos , Encaminhamento e Consulta , Estudos Retrospectivos
8.
J Paediatr Child Health ; 58(9): 1578-1583, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35642299

RESUMO

AIM: To determine the clinical outcomes and evaluate the perspectives of children with Type 1 diabetes (T1D) and their parents managing their child on hybrid closed-loop (HCL) therapy. METHODS: Children with T1D on HCL attending a tertiary diabetes centre between April 2019 and July 2021 were included. A retrospective analysis of glycaemic data was conducted to determine the clinical outcomes. Time spent in closed loop, time in target glucose range (TIR 3.9-10 mmol/L), hypoglycaemia and hyperglycaemia were collected at baseline, 4 weeks, 3 and 6 months post-HCL. User experience was assessed by questionnaires administered to parents of children with T1D. RESULTS: Seventy-one children, mean (SD) age of 12.2 (3.2) years were commenced on HCL. Ten (14%) discontinued HCL use, with 60% discontinuing within the first 6 months. Glycaemic outcomes were analysed in 52 children. Time spent in closed loop was 78 (21) % at 4 weeks, declined to 69 (28) % at 3 months (P = 0.037) and 63 (34) % at 6 months (P = 0.001). The mean %TIR increased from 59.8 at baseline to 67.6 at 3 months and 65.6 at 6 months with a mean adjusted difference of 7.8% points [95% CI 3.6, 11.9] and 5.5% points [95% CI 1.4, 9.5], respectively. There was a reduction in time > 10 mmol/L and time < 3.9 mmol/L from baseline to 6 months. Although families faced challenges with technology, better glucose control with reduced glycaemic fluctuations were reported. CONCLUSIONS: HCL therapy is associated with improved glycaemia; however, adequate support and education are required for best outcomes.


Assuntos
Diabetes Mellitus Tipo 1 , Adolescente , Austrália , Glicemia , Automonitorização da Glicemia , Criança , Diabetes Mellitus Tipo 1/tratamento farmacológico , Humanos , Hipoglicemiantes , Insulina , Sistemas de Infusão de Insulina , Estudos Retrospectivos
9.
Int J Mol Sci ; 23(2)2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35055091

RESUMO

Enzymatic oxidations of thiophenes, including thiophene-containing drugs, are important for biodesulfurization of crude oil and drug metabolism of mono- and poly-cyclic thiophenes. Thiophene oxidative dearomatization pathways involve reactive metabolites, whose detection is important in the pharmaceutical industry, and are catalyzed by monooxygenase (sulfoxidation, epoxidation) and dioxygenase (sulfoxidation, dihydroxylation) enzymes. Sulfoxide and epoxide metabolites of thiophene substrates are often unstable, and, while cis-dihydrodiol metabolites are more stable, significant challenges are presented by both types of metabolite. Prediction of the structure, relative and absolute configuration, and enantiopurity of chiral metabolites obtained from thiophene enzymatic oxidation depends on the substrate, type of oxygenase selected, and molecular docking results. The racemization and dimerization of sulfoxides, cis/trans epimerization of dihydrodiol metabolites, and aromatization of epoxides are all factors associated with the mono- and di-oxygenase-catalyzed metabolism of thiophenes and thiophene-containing drugs and their applications in chemoenzymatic synthesis and medicine.


Assuntos
Dioxigenases/metabolismo , Oxigenases de Função Mista/metabolismo , Oxirredução , Tiofenos/metabolismo , Biotransformação , Catálise , Sistema Enzimático do Citocromo P-450/metabolismo , Inativação Metabólica , Redes e Vias Metabólicas , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Estresse Oxidativo , Ligação Proteica , Relação Estrutura-Atividade , Sulfóxidos/química , Sulfóxidos/metabolismo , Tiofenos/química
10.
J Child Psychol Psychiatry ; 62(8): 961-970, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33164221

RESUMO

BACKGROUND: Birth order effects have been linked to variability in intelligence, educational attainment and sexual orientation. First- and later-born children have been linked to an increased likelihood of an Autism Spectrum Disorder (ASD) diagnosis, with a smaller body of evidence implicating decreases in cognitive functioning with increased birth order. The present study investigated the potential association between birth order and ASD diagnostic phenotypes in a large and representative population sample. METHODS: Data were obtained from an ongoing prospective diagnostic registry, collected between 1999 and 2017, including children (1-18 years of age, n = 5,404) diagnosed with ASD in the state of Western Australia. Children with ASD were ranked relative to sibling's birth to establish birth order within families at time of ASD diagnosis. Information reported to the registry by health professionals at the time of diagnostic evaluation included demographic and family characteristics, functional abilities and intellectual capacity. RESULTS: Adaptive functioning and intelligence scores decreased with increasing birth order, with later-born children more likely to have an intellectual disability. Compared to first-born children with siblings, first-born children without siblings at the time of diagnosis also exhibited decreased cognitive functioning. CONCLUSIONS: These findings demonstrate for the first time an association between increasing birth order and variability in ASD clinical phenotypes at diagnosis, with potential evidence of reproductive curtailment in children without siblings. Taken together, these findings have significant implications for advancing understanding about the potential mechanisms that contribute to heterogeneity in ASD clinical presentations as a function of birth order and family size.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Transtorno do Espectro Autista/diagnóstico , Transtorno do Espectro Autista/epidemiologia , Ordem de Nascimento , Pré-Escolar , Feminino , Humanos , Masculino , Fenótipo , Estudos Prospectivos
11.
Aust N Z J Obstet Gynaecol ; 61(2): 270-274, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33427301

RESUMO

BACKGROUND: Vulvodynia and pudendal neuralgia comprise significant contributors to vulvar-related pain and its impact on daily life. AIM: A retrospective clinical audit was conducted at the Women's Health & Research Institute of Australia, Sydney, to determine the pattern of use and the efficacy of the application of topical amitriptyline 0.5% plus oestriol 0.03% in organogel (AOO), to the vulvar vestibule in reducing the impact of pain on daily life. MATERIALS AND METHODS: There were 1174 patients who received a script from May 2017 until February 2020: 1054 patients agreed to be contacted and had a valid email address. RESULTS: There were 376 (35.7%) patients who replied. Pain with intercourse was the main indication for use. Treatment was rated effective by 51.2% (95% CI: 35.4-66.8%) of patients less than 30 years of age, 66.7% (95% CI: 57.3-74.9%) of patients 30-50 years of age, and 58.3% (95% CI: 50.9-65.4%) in patients over 50. Stinging at the site of application was the most commonly reported side effect. CONCLUSION: Topical AOO is an effective and well-tolerated treatment for vulvar pain.


Assuntos
Dispareunia , Neuralgia do Pudendo , Vulvodinia , Idoso , Amitriptilina , Austrália , Auditoria Clínica , Dispareunia/tratamento farmacológico , Estriol , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Vulvodinia/tratamento farmacológico
12.
Phys Rev Lett ; 125(23): 237402, 2020 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-33337180

RESUMO

Neutral silicon vacancy (SiV^{0}) centers in diamond are promising candidates for quantum networks because of their excellent optical properties and long spin coherence times. However, spin-dependent fluorescence in such defects has been elusive due to poor understanding of the excited state fine structure and limited off-resonant spin polarization. Here we report the realization of optically detected magnetic resonance and coherent control of SiV^{0} centers at cryogenic temperatures, enabled by efficient optical spin polarization via previously unreported higher-lying excited states. We assign these states as bound exciton states using group theory and density functional theory. These bound exciton states enable new control schemes for SiV^{0} as well as other emerging defect systems.

13.
Proc Natl Acad Sci U S A ; 114(41): 10840-10845, 2017 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-28973859

RESUMO

Using temperature-jump infrared spectroscopy, we are able to trigger a gel-to-fluid phase transition in lipid vesicles and monitor in real time how a membrane protein responds to structural changes in the membrane. The melting of lipid domains in 1,2-dimyristoyl-sn-glycero-3-phosphocholine vesicles is observed to occur in as fast as 50 ns, with a temperature dependence characteristic of critical slowing. Gramicidin D (gD) added to the membrane responds primarily to the change in thickness of the membrane on a timescale coincident with the membrane melting. Using structure-based spectral modeling, we assign the conformational changes to compression and rotation of a partially dissociated gD dimer. Free energy calculations indicate that the high rate is a result of near-barrierless diffusion on a protein energy landscape that is radically reshaped by membrane thinning. The structural changes associated with the phase transition are similar to the fluctuation modes of fluid phase membranes, highlighting the importance of understanding the dynamic nature of the membrane environment around proteins.


Assuntos
Membrana Celular/química , Canais Iônicos/química , Bicamadas Lipídicas/química , Transição de Fase , Conformação Proteica , Humanos , Lipídeos de Membrana
14.
Nano Lett ; 19(12): 8928-8933, 2019 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-31765161

RESUMO

Atomic and atomlike defects in the solid state are widely explored for quantum computers, networks, and sensors. Rare earth ions are an attractive class of atomic defects that feature narrow spin and optical transitions that are isolated from the host crystal, allowing incorporation into a wide range of materials. However, the realization of long electronic spin coherence times is hampered by magnetic noise from abundant nuclear spins in the most widely studied host crystals. Here, we demonstrate that Er3+ ions can be introduced via ion implantation into TiO2, a host crystal that has not been studied extensively for rare earth ions and has a low natural abundance of nuclear spins. We observe efficient incorporation of the implanted Er3+ into the Ti4+ site (>50% yield) and measure narrow inhomogeneous spin and optical line widths (20 and 460 MHz, respectively) that are comparable to bulk-doped crystalline hosts for Er3+. This work demonstrates that ion implantation is a viable path to studying rare earth ions in new hosts and is a significant step toward realizing individually addressed rare earth ions with long spin coherence times for quantum technologies.

15.
Horm Behav ; 114: 104542, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31226329

RESUMO

Aggression is a behavioral strategy for securing limited resources and its expression is strongly influenced by their presence and value. In particular, males are generally thought to guard females after mating to ward off other males, but the underlying control mechanisms are unknown. Here, we investigated the role of amines on male courtship behavior and its subsequent effect on male-male aggression in crickets (Gryllus bimaculatus). Contrary to the guarding hypothesis, female presence alone had no immediate effect on male-male aggression. Furthermore, confirming studies on other species, prior female contact, but not necessarily courtship or copulation, promoted subsequent male-male aggression in subordinate, but not socially naive crickets. This promoting effect of female contact is transient and slowly wanes after her removal. Selective aminergic receptor antagonists revealed that the promoting effect of prior female contact on male-male aggression is mediated by octopamine (OA), as well as by serotonin (5HT) acting most likely via 5HT1 and/or 5HT7 like receptors. This contrasts the role of 5HT2-like receptors in maintaining reduced aggressiveness after social defeat. Furthermore, while dopamine (DA) is necessary for the recovery of aggression in subordinates after defeat, it appears to play no part in female induced aggression. Male courtship, on the other hand, is selectively promoted by DA and 5HT, again most likely via 5HT1 and/or 5HT7 like receptors, but not by OA. We conclude that OA, DA and 5HT each differentially modulate different aspects of courtship and aggressive behavior in a context specific fashion.


Assuntos
Agressão/efeitos dos fármacos , Corte , Dopamina/farmacologia , Gryllidae/fisiologia , Octopamina/farmacologia , Serotonina/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos , Animais , Feminino , Masculino
16.
J Org Chem ; 84(23): 15165-15172, 2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31692354

RESUMO

cis-Dihydrodiols, derived from monocyclic aromatic compounds, are valuable chiral pool intermediates for the synthesis of cyclic natural products. A drawback of this approach, to the synthesis of polycyclic secondary metabolites, is that additional rings must be annulated. To date, relatively few chiral natural products have been synthesized from polycyclic arene cis-dihydrodiols. Fungal metabolites, (-)-ribisins A and B, have now been obtained by functional group manipulation of a tricyclic arene metabolite, obtained from toluene dioxygenase-catalyzed regioselective and stereoselective cis-dihydroxylations of dibenzo[b,d]furan. The synthetic sequences were marginally shorter than the alternative routes, using monocyclic arene cis-dihydrodiols, and required no carbon-carbon bond-forming reactions.


Assuntos
Catecóis/química , Furanos/química , Catecóis/síntese química , Conformação Molecular , Estereoisomerismo
17.
Chirality ; 30(1): 5-18, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29024058

RESUMO

The relative merits of the methods employed to determine enantiomeric excess (ee) values and absolute configurations of chiral arene and alkene cis-1,2-diol metabolites, including boronate formation, using racemic or enantiopure (+) and (-)-2-(1-methoxyethyl)phenylboronic acid (MEPBA), are discussed. Further applications of: 1) MEPBA derived boronates of chiral mono- and poly-cyclic arene cis-dihydrodiol, cyclohex-2-en-1-one cis-diol, heteroarene cis/trans-2,3-diol, and catechol metabolites in estimating their ee values, and 2) new chiral phenylboronic acids, 2-[1-methoxy-2,2-dimethylpropyl]phenyl boronic acid (MDPBA) and 2-[1-methoxy-1-phenylmethyl]phenyl boronic acid (MPPBA) and their advantages over MEPBA, as reagents for stereochemical analysis of arene and alkene cis-diol metabolites, are presented.

18.
J Law Med ; 25(4): 1100-1105, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29978687

RESUMO

Risk mitigation practices are essential to protecting patients from harm and reducing medical practitioner exposure to unnecessary reputational damage and economic loss. Despite traditionally being perceived as a low-risk specialty, published data on medico-legal claims against dermatologists in Australia are currently lacking. This article reviews the sources of medico-legal claims against dermatologists in Australia from a single medical indemnity insurer over the most recent three years. The failure to meet patient expectations was the largest source of claims against dermatologists, followed by adverse outcomes. Improved communication from practitioner to patient remains the most effective step to preventing medico-legal claims. Medico-legal claims, when they occur, are more successfully defended when thorough documentation processes are in place.


Assuntos
Dermatologistas/legislação & jurisprudência , Seguradoras/estatística & dados numéricos , Imperícia , Austrália , Dermatologistas/normas , Documentação , Humanos , Responsabilidade Legal
19.
BMC Evol Biol ; 17(1): 3, 2017 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-28049417

RESUMO

BACKGROUND: Due to their phylogenetic position as one of the closest arthropod relatives, studies of the organisation of the nervous system in onychophorans play a key role for understanding the evolution of body segmentation in arthropods. Previous studies revealed that, in contrast to the arthropods, segmentally repeated ganglia are not present within the onychophoran ventral nerve cords, suggesting that segmentation is either reduced or might be incomplete in the onychophoran ventral nervous system. RESULTS: To assess segmental versus non-segmental features in the ventral nervous system of onychophorans, we screened the nerve cords for various markers, including synapsin, serotonin, gamma-aminobutyric acid, RFamide, dopamine, tyramine and octopamine. In addition, we performed retrograde fills of serially repeated commissures and leg nerves to localise the position of neuronal somata supplying those. Our data revealed a mixture of segmental and non-segmental elements within the onychophoran nervous system. CONCLUSIONS: We suggest that the segmental ganglia of arthropods evolved by a gradual condensation of subsets of neurons either in the arthropod or the arthropod-tardigrade lineage. These findings are in line with the hypothesis of gradual evolution of segmentation in panarthropods and thus contradict a loss of ancestral segmentation within the onychophoran lineage.


Assuntos
Artrópodes/anatomia & histologia , Gânglios dos Invertebrados , Animais , Artrópodes/classificação , Artrópodes/metabolismo , Evolução Biológica , Biomarcadores/metabolismo , Sistema Nervoso/anatomia & histologia , Neurônios , Neuropeptídeos , Filogenia , Serotonina/metabolismo
20.
J Am Chem Soc ; 139(13): 4743-4752, 2017 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-28277665

RESUMO

Understanding the electrostatics of lipid membranes at a molecular level has the potential to offer great insight into the mechanism of voltage-gated processes but has been challenging to study experimentally. In this study, we characterize the equilibrium electric field fluctuations at the interfacial region of lipid bilayers by using a combination of ultrafast time-resolved infrared spectroscopy, molecular dynamics (MD) simulations, and spectral modeling. By monitoring the dynamics of the ester carbonyl stretching vibration in hydrated phosphocholine lipid bilayers, we are able to measure a correlation function for the femtosecond and picosecond fluctuations in the local electric field of the membrane, estimating the standard deviation in these fluctuations as ∼10MV/cm. The addition of gramicidin D at a 1:20 mol ratio with DMPC results in the formation of protein-lipid hydrogen bonds, which alter the dynamics of the ester groups. Using MD simulations, we conclude that ultrafast local field fluctuations exist whether or not water interacts with the ester groups; however, water does accelerate the time-scale of these fluctuations.


Assuntos
Dimiristoilfosfatidilcolina/química , Bicamadas Lipídicas/química , Simulação de Dinâmica Molecular , Espectrofotometria Infravermelho , Eletricidade Estática , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA