Thermal Decomposition of Ternary Sodium Graphite Intercalation Compounds.

Graphite intercalation compounds (GICs) are often used to produce exfoliated or functionalised graphene related materials (GRMs) in a specific solvent. This study explores the formation of the Na-tetrahydrofuran (THF)-GIC and a new ternary system based on dimethylacetamide (DMAc). Detailed comparisons of in situ temperature dependent XRD with TGA-MS and Raman measurements reveal a series of dynamic transformations during heating. Surprisingly, the bulk of the intercalation compound is stable under ambient conditions, trapped between the graphene sheets. The heating process drives a reorganisation of the solvent and Na molecules, then an evaporation of the solvent; however, the solvent loss is arrested by restacking of the graphene layers, leading to trapped solvent bubbles. Eventually, the bubbles rupture, releasing the remaining solvent and creating expanded graphite. These trapped dopants may provide useful property enhancements, but also potentially confound measurements of grafting efficiency in liquid-phase covalent functionalization experiments on 2D materials.

Depleting Depletion: Maintaining Single-Walled Carbon Nanotube Dispersions after Graft-To Polymer Functionalization.

Grafting polymers onto single-walled carbon nanotubes (SWCNTs) usefully alters properties but does not typically yield stable, solvated species directly. Despite the expectation of steric stabilization, a damaging (re)dispersion step is usually necessary. Here, poly(vinyl acetate)s (PVAc's) of varying molecular weights are grafted to individualized, reduced SWCNTs at different concentrations to examine the extent of reaction and degree of solvation. The use of higher polymer concentrations leads to an increase in grafting ratio (weight fraction of grafted polymer relative to the SWCNT framework), approaching the limit of random sequentially adsorbed Flory "mushrooms" on the surface. However, at higher polymer concentrations, a larger percentage of SWCNTs precipitate during the reaction; an effect which is more significant for larger weight polymers. The precipitation is attributed to depletion interactions generated by ungrafted homopolymer overcoming Coulombic repulsion of adjacent like-charged SWCNTs; a simple model is proposed. Larger polymers and greater degrees of functionalization favor stable solvation, but larger and more concentrated homopolymers increase depletion aggregation. By using low concentrations (25 µM) of larger molecular weight PVAc (10 kDa), up to 65% of grafted SWCNTs were retained in solution (at 65 µg mL-1) directly after the reaction.

Detecting change in patient outcomes in a rural ambulatory rehabilitation service: the responsiveness of Goal Attainment Scaling and the Lawton Scale.

OBJECTIVE: The Wagga Wagga Ambulatory Rehabilitation Service (WWARS) clinicians felt the Australian Modified Lawton's Instrumental Activities of Daily Living Scale (Lawton Scale) was unresponsive to changes detected in many patients following their individualised programs. This study examined the performance of the Goal Attainment Scaling (GAS) concomitantly with the Lawton Scale in ambulatory rehabilitation patients. METHODS: Consecutive patients (n = 83) of WWARS were evaluated pre and post treatment with the Lawton Scale and GAS. The statistical properties, particularly responsiveness, of the scales were compared. RESULTS: Statistically significant change (P < 0.001) was observed following treatment on both the Lawton Scale and GAS. Mean GAS scores changed by 38.7% compared with 8.3% for the Lawton Scale. GAS demonstrated a greater effect size (Cliff's δ) of 1.67 (95% confidence interval 1.51-1.91) than the Lawton Scale 0.83 (95% confidence interval 0.57-0.94). In 33.7% of patients, the Lawton Scale was invariant but improved with GAS. CONCLUSIONS: GAS was a more responsive measure than the Lawton Scale in rural ambulatory rehabilitation patients. Consequently, GAS is recommended as a performance outcome measure in the evaluation of ambulatory rehabilitation services to supplement standardised outcome measures such as the Lawton Scale.

Early life thymectomy induces arterial dysfunction in mice.

Aging of the arteries is characterized by increased large artery stiffness and impaired endothelium-dependent dilation. We have previously shown that in old (22-24 month) mice T cells accumulate within aorta and mesentery. We have also shown that pharmacologic and genetic deletion of these T cells ameliorates age-related arterial dysfunction. These data indicate that T cells contribute to arterial aging; however, it is unknown if aged T cells alone can induce arterial dysfunction in otherwise young mice. To produce an aged-like T cell phenotype, mice were thymectomized at three-weeks of age or were left with their thymus intact. At 9 months of age, thymectomized mice exhibited greater proportions of both CD4 + and CD8 + memory T cells compared to controls in the blood. Similar changes were observed in the T cells accumulating in the aorta and mesentery. We also observed greater numbers of proinflammatory cytokine producing T cells in the aorta and mesentery. The phenotypic T cell changes in the blood, aorta and mesentery of thymectomized mice were similar to those observed when we compared young (4-6 month) to old thymus intact mice. Along with these alterations, compared to controls, thymectomized mice exhibited augmented large artery stiffness and greater aortic collagen deposition as well as impaired mesenteric artery endothelium dependent dilation due to blunted nitric oxide bioavailability. These results indicate that early life thymectomy results in arterial dysfunction and suggest that an aged-like T cell phenotype alone is sufficient to induce arterial dysfunction in otherwise young mice.

Structure and morphology of charged graphene platelets in solution by small-angle neutron scattering.

Solutions of negatively charged graphene (graphenide) platelets were produced by intercalation of nanographite with liquid potassium-ammonia followed by dissolution in tetrahydrofuran. The structure and morphology of these solutions were then investigated by small-angle neutron scattering. We found that >95 vol % of the solute is present as single-layer graphene sheets. These charged sheets are flat over a length scale of >150 Å in solution and are strongly solvated by a shell of solvent molecules. Atomic force microscopy on drop-coated thin films corroborated the presence of monolayer graphene sheets. Our dissolution method thus offers a significant increase in the monodispersity achievable in graphene solutions.

Pre-race and race management impacts serum muscle enzyme activity in Australian endurance horses.

BACKGROUND: Marked increases in serum muscle enzyme activity can occur in endurance horses but the diagnostic certainty in predicting cases of myopathy is unclear. Improved understanding of horse management effects on serum muscle enzyme activity as markers of muscle health would assist interpretation of serum muscle enzyme activity and guide management to reduce myopathy risk. OBJECTIVES: To investigate associations between serum muscle enzyme activity and management factors in endurance horses. STUDY DESIGN: Cross-sectional study. METHODS: One hundred endurance horses competing in four endurance events (offering distances of 20-120 km) in south-eastern Australia were observed. Data were collected from official horse logbooks, pre-and post-race serum samples, an owner questionnaire of pre-race and race management of horses and the Australian Endurance Riders Association results database. Multivariable linear regression modelling tested associations between management factors and serum muscle enzyme activity. RESULTS: First leg speed, distance raced, number of rest days pre-race, and pre-race activity of aspartate aminotransferase (AST) and creatine kinase (CK) explained 47.3% of the variance in post-race CK. As first leg speed increased by 1 km/h, CK activity increased by 25.8% (95% CI 11%-35%). Race distances >80 km increased post-race CK activity by 124% (95% CI 116%-145%). Each additional pre-race rest day increased post-race CK activity by 30.5% (95% CI 11%-42%). Modelling a 10% increase in pre-race CK and pre-race AST activity was associated with post-race CK activity increasing by 7.3% (95% CI 3%-14.4%) and 8.5% (95% CI 0.3%-14.2%) respectively. Horses experiencing training distances >40 km and a greater number of rest days prior to race day developed increased pre-race AST and CK activity respectively. MAIN LIMITATIONS: Owner questionnaires may be subject to bias. Limited data were available to model ride terrain, horse fitness, ration detail and myopathy. Muscle biopsies were not used to confirm myopathy. CONCLUSIONS: Nearly half of the variation in post-race CK activity observed can be attributed to management factors unrelated to myopathy, suggesting increased CK activity may not be pathognomonic for myopathy. We advise caution in relying solely on serum muscle enzyme activity for diagnosis of myopathy until the strength of association between CK and myopathy is further ascertained in future studies.

T lymphocyte depletion ameliorates age-related metabolic impairments in mice.

Both glucose tolerance and adaptive immune function exhibit significant age-related alterations. The influence of the immune system on obesity-associated glucose intolerance is well characterized; however, whether the immune system contributes to age-related glucose intolerance is not as well understood. Here, we report that advancing age results in an increase in T cell infiltration in the epididymal white adipose tissue (eWAT), liver, and skeletal muscle. Subtype analyses show that both CD4+, CD8+ T cells are greater with advancing age in each of these tissues and that aging results in a blunted CD4 to CD8 ratio. Anti-CD3 F(ab')2 fragments depleted CD4+ and CD8+ cells in eWAT, CD4+ cells only in the liver, and did not deplete quadriceps T cells. In old mice, T cells producing both interferon-γ and tumor necrosis factor-α are accumulated in the eWAT and liver, and a greater proportion of skeletal muscle T cells produced interferon-γ. Aging resulted in increased proportion and numbers of T regulatory cells in eWAT, but not in the liver or muscle. Aging also resulted in greater numbers of eWAT and quadriceps CD206- macrophages and eWAT, liver and quadriceps B cells; neither cell type was altered by anti-CD3 treatment. Anti-CD3 treatment improved glucose tolerance in old mice and was accompanied by improved signaling related to liver and skeletal muscle insulin utilization and decreased gluconeogenesis-related gene expression in the liver. Our findings indicate a critical role of the adaptive immune system in the age-related metabolic dysfunction.

First-drug treatment failures in children newly diagnosed with epilepsy.

In adults newly diagnosed with epilepsy, treatment with the first prescribed antiepileptic drug fails for approximately one half. In two studies that addressed this question in children, the failure rates were 20% and 40%. The present study used a detailed chart review of children newly diagnosed with epilepsy over a 4-year span in a major childhood epilepsy referral clinic to assess (1) the percentage of children for whom first-line antiepileptic drug treatment failed and (2) the reasons for the treatment failure. Charts were reviewed for 95 children who were diagnosed with epilepsy, started on their first antiepileptic drug, and then monitored for approximately 5 years. Of these 95 children, 48 were classified as having idiopathic epilepsy (50.5 %), 30 as having cryptogenic epilepsy (31.6%), and 17 as having symptomatic epilepsy (17.9%). The two main antiepileptic drugs used were valproic acid (43.2% of patients) and carbamazepine (38.9% of patients). Treatment with the first antiepileptic drug failed in 30/95 children (31.6%). Treatment failure was due to adverse effects in 12/30 children (40.0%), due to lack of efficacy in 11/30 (37.9%), and due to both adverse effects and lack of efficacy in 7/30 (24.1%). Also examined was the effect on treatment failure of patient age at diagnosis, antiepileptic drug choice, maximum drug dose, etiology of epilepsy, and particular epilepsy syndromes on treatment failures; there was no statistically significant effect of any of these variables on first-line treatment outcome. In this population, approximately one third of children newly diagnosed with epilepsy experienced treatment failure with the first antiepileptic drug used. Lack of efficacy and unacceptable adverse effects contributed equally to these treatment failures.

Nurse experiences and confidence in treating critically ill and injured patients following the completion of the First Line Emergency Care Course.

INTRODUCTION: The geographical vastness of Australia in rural and remote regions provides challenges for hospital nursing staff when a medical officer is not immediately available. Delaying treatment until a medical officer arrives can potentially impact on patient outcomes. Some Registered Nurses in rural and remote New South Wales have received advanced training and credentialing through the First Line Emergency Care Course (FLECC) enabling them to initiate treatment prior to the medical officer's arrival. Despite operating since 1990 the course and subsequent model of care has received limited evaluation. PURPOSE: The aim of this study was to evaluate whether undertaking the First Line Emergency Care Course (FLECC) improves confidence in rural and remote registered nurses' (RN) ability to provide and to initiate extended scope of practice for emergency care of critically ill adults in the absence of a medical officer. PROCEDURE: A voluntary electronic cross sectional 19 question multi-centre survey was emailed to all nurses FLECC accredited since 2008 and employed in rural and remote Local Health District in New South Wales. FINDINGS: A response rate of 60% was obtained (225/375). Since credentialing 93.3% nurses had commenced emergency treatments under the approved guidelines. The majority (97.4%) agreed that the course provided the required knowledge. The mean Likert nurse's self-assessed confidence score (1-5) for providing first line response rose significantly (Wilcoxon signed rank test V=375, p-value<0.0001) from 2.47 and up to 3.98 after the course. The majority (83.9%) now had "high" or "very high" confidence. PRINCIPLE CONCLUSIONS: The FLECC provides registered nurses in rural and remote areas with skills, confidence, knowledge and ability to initiate potentially lifesaving treatment for critically ill or injured patients prior to the arrival of a medical officer. The FLECC model of care helps provide timely care delivery by nurses in rural and remote areas. Further research could examine the differences in outcome in patients treated at sites with FLECC nurses.

Novel pathogenic COX20 variants causing dysarthria, ataxia, and sensory neuropathy.

COX20/FAM36A encodes a mitochondrial complex IV assembly factor important for COX2 activation. Only one homozygous COX20 missense mutation has been previously described in two separate consanguineous families. We report four subjects with features that include childhood hypotonia, areflexia, ataxia, dysarthria, dystonia, and sensory neuropathy. Exome sequencing in all four subjects identified the same novel COX20 variants. One variant affected the splice donor site of intron-one (c.41A>G), while the other variant (c.157+3G>C) affected the splice donor site of intron-two. cDNA and protein analysis indicated that no full-length cDNA or protein was generated. These subjects expand the phenotype associated with COX20 deficiency.

Switchable changes in the conductance of single-walled carbon nanotube networks on exposure to water vapour.

We have discovered that wrapping single-walled carbon nanotubes (SWCNTs) with ionic surfactants induces a switch in the conductance-humidity behaviour of SWCNT networks. Residual cationic vs. anionic surfactant induces a respective increase or decrease in the measured conductance across the SWCNT networks when exposed to water vapour. The magnitude of this effect was found to be dependent on the thickness of the deposited SWCNT films. Previously, chemical sensors, field effect transistors (FETs) and transparent conductive films (TCFs) have been fabricated from aqueous dispersions of surfactant functionalised SWCNTs. The results reported here confirm that the electrical properties of such components, based on randomly orientated SWCNT networks, can be significantly altered by the presence of surfactant in the SWCNT layer. A mechanism for the observed behaviour is proposed based on electrical measurements, Raman and UV-Vis-NIR spectroscopy. Additionally, the potential for manipulating the sensitivity of the surfactant functionalised SWCNTs to water vapour for atmospheric humidity sensing was evaluated. The study also presents a simple method to establish the effectiveness of surfactant removal techniques, and highlights the importance of characterising the electrical properties of SWCNT-based devices in both dry and humid operating environments for practical applications.

Chemical routes to discharging graphenides.

Chemical and electrochemical reduction methods allow the dispersion, processing, and/or functionalization of discrete sp2-hybridised nanocarbons, including fullerenes, nanotubes and graphenes. Electron transfer to the nanocarbon raises the Fermi energy, creating nanocarbon anions and thereby activating an array of possible covalent reactions. The Fermi level may then be partially or fully lowered by intended functionalization reactions, but in general, techniques are required to remove excess charge without inadvertent covalent reactions that potentially degrade the nanocarbon properties of interest. Here, simple and effective chemical discharging routes are demonstrated for graphenide polyelectrolytes and are expected to apply to other systems, particularly nanotubides. The discharging process is inherently linked to the reduction potentials of such chemical discharging agents and the unusual fundamental chemistry of charged nanocarbons.

Ionic solutions of two-dimensional materials.

Strategies for forming liquid dispersions of nanomaterials typically focus on retarding reaggregation, for example via surface modification, as opposed to promoting the thermodynamically driven dissolution common for molecule-sized species. Here we demonstrate the true dissolution of a wide range of important 2D nanomaterials by forming layered material salts that spontaneously dissolve in polar solvents yielding ionic solutions. The benign dissolution advantageously maintains the morphology of the starting material, is stable against reaggregation and can achieve solutions containing exclusively individualized monolayers. Importantly, the charge on the anionic nanosheet solutes is reversible, enables targeted deposition over large areas via electroplating and can initiate novel self-assembly upon drying. Our findings thus reveal a unique solution-like behaviour for 2D materials that enables their scalable production and controlled manipulation.

Epidemiology and Outcomes of Arterial Ischemic Stroke in Children: The Canadian Pediatric Ischemic Stroke Registry.

BACKGROUND: Pediatric arterial ischemic stroke remains incompletely understood. Population-based epidemiological data inform clinical trial design but are scant in this condition. We aimed to determine age-specific epidemiological characteristics of arterial ischemic stroke in neonates (birth to 28 days) and older children (29 days to 18 years). METHODS: We conducted a 16-year, prospective, national population-based study, the Canadian Pediatric Ischemic Stroke Registry, across all 16 Canadian acute care children's hospitals. We prospectively enrolled children with arterial ischemic stroke from January 1992 to December 2001 and documented disease incidence, presentations, risk factors, and treatments. Study outcomes were assessed throughout 2008, including abnormal clinical outcomes (stroke-related death or neurological deficit) and recurrent arterial ischemic stroke or transient ischemic attack. RESULTS: Among 1129 children enrolled with arterial ischemic stroke, stroke incidence was 1.72/100,000/year, (neonates 10.2/100,000 live births). Detailed clinical and radiological information were available for 933 children (232 neonates and 701 older children, 55% male). The predominant clinical presentations were seizures in neonates (88%), focal deficits in older children (77%), and diffuse neurological signs (54%) in both. Among neonates, 44% had no discernible risk factors. In older children, arteriopathy (49% of patients with vascular imaging), cardiac disorders (28%), and prothrombotic disorders (35% of patients tested) predominated. Antithrombotic treatment increased during the study period (P < 0.001). Stroke-specific mortality was 5%. Outcomes included neurological deficits in 60% of neonates and 70% of older children. Among neonates, deficits emerged during follow-up in 39%. Overall, an initially decreased level of consciousness, a nonspecific systemic presentation, and the presence of stroke risk factors predicted abnormal outcomes. For neonates, predictors were decreased level of consciousness, nonspecific systemic presentation, and basal ganglia infarcts. For older children, predictors were initial seizures, nonspecific systemic presentation, risk factors, and lack of antithrombotic treatment. Recurrent arterial ischemic stroke or transient ischemic attack developed in 12% of older children and was predicted by arteriopathy, presentation without seizures, and lack of antithrombotic treatment. Emerging deficit was predicted by neonatal age at stroke and by cardiac disease. CONCLUSIONS: This national data set provides a population-based disease incidence rate and demonstrates the protective effect of antithrombotic treatment in older children, and frequent long-term emerging deficits in neonates and in children with cardiac disorders. Further clinical trials are required to develop effective age-appropriate treatments for children with acute arterial ischemic stroke.

Controlling the Cross-Sensitivity of Carbon Nanotube-Based Gas Sensors to Water Using Zeolites.

Carbon nanotube-based gas sensors can be used to detect harmful environmental pollutants such as NO2 at room temperature. Although they show promise as low-powered, sensitive, and affordable monitoring devices, cross-sensitivity of functionalized carbon nanotubes to water vapor often obscures the detection of target molecules. This is a barrier to adoption for monitoring of airborne pollutants because of the varying humidity levels found in real world environments. Zeolites, also known as molecular sieves because of their selective adsorption properties, are used in this work to control the cross-sensitivity of single-walled carbon nanotube (SWCNT)-based sensors to water vapor. Zeolites incorporated into the sensing layer are found to reduce interference effects that would otherwise obscure the identification of NO2 gas, permitting repeatable detection over a range of relative humidities. This significant improvement is found to depend on the arrangement of the SWCNT-zeolite layers in the sensing device, as well as the hydrophilicity of the chosen zeolite.

Partial seizures triggering infantile spasms in the presence of a basal ganglia glioma.

Infantile spasms associated with brain tumors have been reported. A focal cortical lesion can induce infantile spasms by triggering the brainstem and basal ganglia in this vulnerable age group. We report the case of a female infant with a low-grade glioma in the right basal ganglia, spreading to the cortical area. She presented at the age of five months with left hemiparesis and partial seizures. She developed infantile spasms at the age of 12 months. This is the first video clip report of partial seizures triggering symmetrical spasms in series, secondary to a basal ganglia glioma extending to the cortex. [Published with video sequences].

Probing the charging mechanisms of carbon nanomaterial polyelectrolytes.

Chemical charging of single-walled carbon nanotubes (SWCNTs) and graphenes to generate soluble salts shows great promise as a processing route for electronic applications, but raises fundamental questions. The reduction potentials of highly-charged nanocarbon polyelectrolyte ions were investigated by considering their chemical reactivity towards metal salts/complexes in forming metal nanoparticles. The redox activity, degree of functionalisation and charge utilisation were quantified via the relative metal nanoparticle content, established using thermogravimetric analysis (TGA), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and X-ray photoelectron spectroscopy (XPS). The fundamental relationship between the intrinsic nanocarbon electronic density of states and Coulombic effects during charging is highlighted as an important area for future research.

The effect of a general practice after-hours clinic on emergency department presentations: a regression time series analysis.

OBJECTIVE: To assess the impact of the opening of an after-hours general practice clinic on the number of daily low-urgency presentations to the nearby emergency department. DESIGN, PARTICIPANTS AND SETTING: Retrospective time series analysis of emergency presentation data, from the New South Wales Health Emergency Department Information System, for all patients presenting to the emergency department of Wagga Wagga Base Hospital between January 1998 and October 2008. MAIN OUTCOME MEASURES: Daily emergency department presentations, before and after the March 2003 opening of the after-hours clinic, of patients triaged as Australasian Triage Scale (ATS) category 4 or 5 (at any time of day, and during the hours of operation of the clinic), and of patients triaged as ATS category 1, 2 or 3 (at any time of day). RESULTS: After adjusting for long-term trends and weekly and annual cycles, the opening of the after-hours clinic was associated with a daily reduction of 7.04 patients (95% CI, 5.39-8.70) in emergency department presentations with an ATS category of 4 or 5. This represented an 8.2% reduction in total presentations (95% CI, 6.2%-10.2%). Presentations of ATS category 1, 2 or 3 patients rose by 1.36 patients a day (95% CI, 0.36-2.35), representing 1.6% of total presentations (95% CI, 0.4%-2.7%). The impact of the after-hours clinic was best modelled by a gradual permanent change. CONCLUSION: An after-hours general practice clinic was associated with a reduction in low-urgency presentations to the emergency department in Wagga Wagga.