2,387 research outputs found

    Oil spill source identification using colorimetric detection

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    The colorimetric detection of polycyclic aromatic hydrocarbons (PAHs) was investigated for the quick and easy identification of likely oil spill offenders. In this new technology, photochromic compounds were used to sense PAHs by varying their photoswitching capacity. To that end, three photochromes were designed and showed varying degrees of photoswitching inhibition depending on PAH analyte, photochrome and excitation wavelength. PAH mixtures that mimic oil spills showed the same varying response and demonstrated the accuracy of this technology. To prove the applicability of this technology, an array was assembled using the three photochromes at three excitation wavelengths and tested against authentic crude oil samples. Not only could these samples be differentiated, weathering of two distinctly different oil samples showed limited variation in response, demonstrating that this may be a viable technique for in situ oil identification

    Effect of a mobile phone intervention for female sex workers on unintended pregnancy in Kenya (WHISPER or SHOUT): a cluster-randomised controlled trial

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    Background: Female sex workers in low-income and middle-income countries face high risks of unintended pregnancy. We developed a 12-month, multifaceted short messaging service intervention (WHISPER) for female sex workers in Kenya who had the potential to become pregnant, to improve their contraceptive knowledge and behaviours. The aim of this study was to assess the effectiveness of the intervention to reduce the incidence of unintended pregnancy among sex workers in Kenya compared with an equal-attention control group receiving nutrition-focused messages (SHOUT). Methods: Our two-arm, cluster-randomised controlled trial was done in sex-work venues in two subcounties of Mombasa, Kenya (Kisauni and Changamwe). Participants, aged 16–34 years, not pregnant or planning pregnancy, able to read text messages in English, residing in the study area, and who had a personal mobile phone with one of two phone networks, were recruited from 93 randomly selected sex-work venues (clusters). Random cluster allocation (1:1) to the intervention or control group was concealed from participants and researchers until the intervention started. Both groups received text messages in English delivered two to three times per week for 12 months (137 messages in total), as well as additional on-demand messages. Message content in the intervention group focused on promotion of contraception, particularly long-acting reversible contraception and dual method contraceptive use; message content in the control group focused on promotion of nutritional knowledge and practices, including food safety, preparation, and purchasing. The primary endpoint, analysed in all participants who were randomly assigned and attended at least one follow-up visit, compared unintended pregnancy incidence between groups using discrete-time survival analysis at 6 and 12 months. This trial is registered with Australian New Zealand Clinical Trials Registry, ACTRN12616000852459, and is closed to new participants. Findings: Between Sept 14, 2016, and May 16, 2017, 1728 individuals were approached to take part in the study. Of these, 1155 were eligible for full screening, 1035 were screened, and 882 were eligible, enrolled, and randomly assigned (451 participants from 47 venues in the intervention group; 431 participants from 46 venues in the control group). 401 participants from the intervention group and 385 participants from the control group were included in the primary analysis. Incidence of unintended pregnancy was 15·5 per 100 person-years in the intervention group and 14·7 per 100 person-years in the control group (hazard ratio 0·98, 95% CI 0·69–1·39). Interpretation The intervention had no measurable effect on unintended pregnancy incidence. Mobile health interventions, even when acceptable and rigorously designed, are unlikely to have a sufficient effect on behaviour among female sex workers to change pregnancy incidence when used in isolation. Funding: National Health and Medical Research Council of Australia

    Sensitivity of composite scores to amyloid burden in preclinical Alzheimer\u27s disease: Introducing the Z-scores of Attention, Verbal fluency, and Episodic memory for Nondemented older adults composite score

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    Introduction: Cognitive composite scores developed for preclinical Alzheimer\u27s disease (AD) often consist of multiple cognitive domains as they may provide greater sensitivity to detect β-amyloid (Aβ)-related cognitive decline than episodic memory (EM) composite scores alone. However, this has never been empirically tested. We compared the rate of cognitive decline associated with high Aβ (Aβ+) and very high Aβ (Aβ++) in cognitively normal (CN) older adults on three multidomain cognitive composite scores and one single-domain (EM) composite score. Methods: CN older adults (n = 423) underwent Aβ neuroimaging and completed neuropsychological assessments at baseline, and at 18-, 36-, 54-, and 72-month follow-ups. Four cognitive composite scores were computed: the ADCS-PACC (ADCS-Preclinical Alzheimer Cognitive Composite), ADCS-PACC without the inclusion of the mini-mental state examination (MMSE), an EM composite, and the Z-scores of Attention, Verbal fluency, and Episodic memory for Nondemented older adults (ZAVEN) composite. Results: Compared with Aβ+ CN older adults, Aβ++ CN older adults showed faster rates of decline across all cognitive composites, with the largest decline observed for ZAVEN composite (d = 1.07). Similarly, compared with Aβ- CN older adults, Aβ+ CN older adults also showed faster rates of cognitive decline, but only for the ADCS-PACC no MMSE (d = 0.43), EM (d = 0.53), and ZAVEN (d = 0.50) composites. Discussion: Aβ-related cognitive decline is best detected using validated neuropsychological instruments. Removal of the MMSE from the ADCS-PACC and replacing it with a test of executive function (verbal fluency; i.e., the ZAVEN) rendered this composite more sensitive even in detecting Aβ-related cognitive decline between Aβ+ and Aβ++ CN older adults

    BDNF Val66Met moderates memory impairment, hippocampal function and tau in preclinical autosomal dominant Alzheimer’s disease

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    The brain-derived neurotrophic factor ( BDNF ) Val66Met polymorphism is implicated in synaptic excitation and neuronal integrity, and has previously been shown to moderate amyloid-β-related memory decline and hippocampal atrophy in preclinical sporadic Alzheimer’s disease. However, the effect of BDNF in autosomal dominant Alzheimer’s disease is unknown. We aimed to determine the effect of BDNF Val66Met on cognitive function, hippocampal function, tau and amyloid-β in preclinical autosomal dominant Alzheimer’s disease. We explored effects of apolipoprotein E ( APOE ) ε4 on these relationships. The Dominantly Inherited Alzheimer Network conducted clinical, neuropsychological, genetic, biomarker and neuroimaging measures at baseline in 131 mutation non-carriers and 143 preclinical autosomal dominant Alzheimer’s disease mutation carriers on average 12 years before clinical symptom onset. BDNF genotype data were obtained for mutation carriers (95 Val 66 homozygotes, 48 Met 66 carriers). Among preclinical mutation carriers, Met 66 carriers had worse memory performance, lower hippocampal glucose metabolism and increased levels of cerebrospinal fluid tau and phosphorylated tau (p-tau) than Val 66 homozygotes. Cortical amyloid-β and cerebrospinal fluid amyloid-β 42 levels were significantly different from non-carriers but did not differ between preclinical mutation carrier Val 66 homozygotes and Met 66 carriers. There was an effect of APOE on amyloid-β levels, but not cognitive function, glucose metabolism or tau. As in sporadic Alzheimer’s disease, the deleterious effects of amyloid-β on memory, hippocampal function, and tau in preclinical autosomal dominant Alzheimer’s disease mutation carriers are greater in Met 66 carriers. To date, this is the only genetic factor found to moderate downstream effects of amyloid-β in autosomal dominant Alzheimer’s disease

    Hypertrophic cardiomyopathy detection with artificial intelligence electrocardiography in international cohorts: an external validation study

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    Aims: Recently, deep learning artificial intelligence (AI) models have been trained to detect cardiovascular conditions, including hypertrophic cardiomyopathy (HCM), from the 12-lead electrocardiogram (ECG). In this external validation study, we sought to assess the performance of an AI-ECG algorithm for detecting HCM in diverse international cohorts. Methods and results: A convolutional neural network-based AI-ECG algorithm was developed previously in a single-centre North American HCM cohort (Mayo Clinic). This algorithm was applied to the raw 12-lead ECG data of patients with HCM and non-HCM controls from three external cohorts (Bern, Switzerland; Oxford, UK; and Seoul, South Korea). The algorithm’s ability to distinguish HCM vs. non-HCM status from the ECG alone was examined. A total of 773 patients with HCM and 3867 non-HCM controls were included across three sites in the merged external validation cohort. The HCM study sample comprised 54.6% East Asian, 43.2% White, and 2.2% Black patients. Median AI-ECG probabilities of HCM were 85% for patients with HCM and 0.3% for controls (P < 0.001). Overall, the AI-ECG algorithm had an area under the receiver operating characteristic curve (AUC) of 0.922 [95% confidence interval (CI) 0.910–0.934], with diagnostic accuracy 86.9%, sensitivity 82.8%, and specificity 87.7% for HCM detection. In age- and sex-matched analysis (case–control ratio 1:2), the AUC was 0.921 (95% CI 0.909–0.934) with accuracy 88.5%, sensitivity 82.8%, and specificity 90.4%. Conclusion: The AI-ECG algorithm determined HCM status from the 12-lead ECG with high accuracy in diverse international cohorts, providing evidence for external validity. The value of this algorithm in improving HCM detection in clinical practice and screening settings requires prospective evaluation

    Rates of age- and amyloid β-associated cortical atrophy in older adults with superior memory performance

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    Introduction: Superior cognitive performance in older adults may reflect underlying resistance to age-associated neurodegeneration. While elevated amyloid b (Ab) deposition (Ab1) has been associated with increased cortical atrophy, it remains unknown whether “SuperAgers” may be protected from Ab-associated neurodegeneration. Methods: Neuropsychologically defined SuperAgers (n 5 172) and cognitively normal for age (n 5 172) older adults from the Australian Imaging, Biomarkers and Lifestyle study were case matched. Rates of cortical atrophy over 8 years were examined by SuperAger classification and Ab status. Results: Of the case-matched SuperAgers and cognitively normal for age older adults, 40.7% and 40.1%, respectively, were Ab1. Rates of age- and Ab-associated atrophy did not differ between the groups on any measure. Ab2 individuals displayed the slowest rates of atrophy. Discussion: Maintenance of superior memory in late life does not reflect resistance to age- or Abassociated atrophy. However, those individuals who reached old age without cognitive impairment nor elevated Ab deposition (i.e. Ab2) displayed reduced rates of cortical atrophy
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