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Data collection is an integral part of any citizen science project. Given the wide variety of projects, some level of expertise or, alternatively, some guidance for novice participants can greatly improve the quality of the collected data. A significant portion of citizen science projects depends on visual data, where photos or videos of different subjects are needed. Often these visual data are collected from all over the world, including remote locations. In this article, we introduce an authoring platform for easily creating mobile apps for citizen science projects that are empowered with client-side machine learning (ML) guidance. The apps created with our platform can help participants recognize the correct data and increase the efficiency of the data collection process. We demonstrate the application of our proposed platform with two use cases: a rip current detection app for a planned pilot study and a detection app for biodiversity-related projects.

The global obesity epidemic has resulted in significant morbidity and mortality. However, the medical treatment of obesity is limited. Gastric bypass is an effective surgical treatment but carries signifi cant perioperative risks. The gut hormones, peptide tyrosine tyrosine (PYY) and glucagon-like peptide 1 (GLP-1), are elevated following gastric bypass and have been shown to reduce food intake. They may provide new therapeutic targets. This review article provides an overview of the central control of food intake and the role of PYY and GLP-1 in appetite control. Key translational animal and human studies are reviewed. (Gut Liver 2012;6:10-20)

The obesity epidemic has a direct impact on every aspect of health. Current strategies to treat obesity are limited and there is a need to pioneer novel solutions. Anorectic gut hormones, physiologically secreted post-prandially to mediate satiety, have recently emerged as potential therapeutic targets in obesity. Peptide tyrosine tyrosine (PYY) is one such anorectic gut hormone, secreted from entero-endocrine L cells, which acts on neuropeptide Y (NPY) receptors within the central appetite circuit. Since the first intravenous administration of PYY to man nearly a decade ago, a number of translational studies and clinical trials have ensued with a view to developing this peptide as a treatment for obesity. This review reports on the current state of play of this on-going research.

Summary Obesity is a major public health issue worldwide. Understanding how the brain controls appetite offers promising inroads toward new therapies for obesity. Peptide YY (PYY) and glucagon-like peptide 1 (GLP-1) are coreleased postprandially and reduce appetite and inhibit food intake when administered to humans. However, the effects of GLP-1 and the ways in which PYY and GLP-1 act together to modulate brain activity in humans are unknown. Here, we have used functional MRI to determine these effects in healthy, normal-weight human subjects and compared them to those seen physiologically following a meal. We provide a demonstration that the combined administration of PYY3-36 and GLP-17-36 amide to fasted human subjects leads to similar reductions in subsequent energy intake and brain activity, as observed physiologically following feeding., Highlights ► Coadministration of PYY3-36 and GLP-17-36 amide reduces food intake and brain activity ► The reduction in brain activity is notable in areas that control appetitive behavior ► Changes in food intake and brain activity are similar to that observed after a meal

Functional magnetic resonance imaging (fMRI) has provided the opportunity to safely investigate the workings of the human brain. This paper focuses on its use in the field of human appetitive behaviour and its impact in obesity research. In the present absence of any safe or effective centrally acting appetite suppressants, a better understanding of how appetite is controlled is vital for the development of new antiobesity pharmacotherapies. Early functional imaging techniques revealed an attenuation of brain reward area activity in response to visual food stimuli when humans are fed—in other words, the physiological state of hunger somehow increases the appeal value of food. Later studies have investigated the action of appetite modulating hormones on the fMRI signal, showing how the attenuation of brain reward region activity that follows feeding can be recreated in the fasted state by the administration of anorectic gut hormones. Furthermore, differences in brain activity between obese and lean individuals have provided clues about the possible aetiology of overeating. The hypothalamus acts as a central gateway modulating homeostatic and nonhomeostatic drives to eat. As fMRI techniques constantly improve, functional data regarding the role of this small but hugely important structure in appetite control is emerging.

Background Kisspeptin (encoded by the KISS1 gene) is a crucial regulator of normal reproductive function. In human beings, KISS1 deletion results in a failure to go through puberty whereas activating mutations result in central precocious puberty. Administration of kisspeptin induces ovulation in rodents and sheep, but whether exogenous kisspeptin can alter the menstrual cycle in healthy women is not known. This study aimed to determine the effects of kisspeptin administration on the menstrual cycle in healthy women. Methods A prospective, single-blinded, one-way crossover study at Imperial College, London, was performed. Five healthy female volunteers aged 24–37 years were recruited through adverts in the local press. They each received twice-daily subcutaneous injections of kisspeptin-54 or saline for 7 days during days 7 to 14 of their menstrual cycle. All women underwent serial assessments of basal reproductive hormones, ultrasound measurements, and luteinising hormone (LH) pulsatility, as well assessment of acute sensitivity to gonadotrophin-releasing hormone (GnRH) and kisspeptin injection. Because of the intensive protocol, women attended for assessments every 2–3 days throughout the cycle, rather than daily, to minimise stress and enhance compliance. Ethics approval was granted by the Hammersmith and Queen Charlotte's and Chelsea Hospitals Research Ethics Committee (registration number 05/Q0406/142). Findings Kisspeptin-54 treatment shortened the menstrual cycle (mean length of menstrual cycle: saline 28·6 days [SE 3·1] vs kisspeptin 26·8 [3·1], p=0·0043), advanced the onset of highest recorded serum LH (mean menstrual day of highest recorded LH 15·2 [SE 2·9] vs 13·0 [4·1], p=0·0372), and advanced the onset of the luteal phase of the menstrual cycle (mean menstrual day of progesterone increase 18·0 [SE 2·1] vs 15·8 [2·0], p=0·0402). On menstrual day 15, the largest ovarian follicle had a significantly higher diameter after kisspeptin-54 than after saline (mean diameter of largest follicle saline 10·0 mm [SE 4·4] vs kisspeptin 15·5 mm [2·2], p=0·04). LH pulsatility was maintained during kisspeptin-54 treatment. Sensitivity to exogenous kisspeptin-54 and exogenous GnRH was maintained during twice-daily kisspeptin-54 administration. Interpretation We have shown, for the first time to our knowledge using biochemical and radiological data, that exogenous kisspeptin-54 advances the menstrual cycle in healthy women. These data have important therapeutic implications for the use of kisspeptin in the treatment of women with reproductive disorders. Even though participants attended every 2–3 days rather than daily, statistical significance in key parameters was still achieved, confirming the strength of the data. In addition, use of both biochemical and radiological data allowed detailed analysis of the underlying physiological processes. Funding Wellcome Trust, National Institute for Health Research, UK Medical Research Council.

Functional magnetic resonance imaging has become a powerful tool to investigate the neuroendocrinology of appetite. In a recent study, we demonstrated that the brain activation pattern seen following the infusion of the anorectic gut hormones PYY3–36 and GLP-17–36 amide to fasted individuals resembles the brain activation pattern seen in the physiological satiated state. This commentary discusses the significance of these findings and compares them with other landmark studies in the field, with specific reference to the brain areas involved in appetite regulation. We highlight the importance of this type of research in order to pave the way for the development of efficacious and safe anti-obesity therapies.