Integrated sampling-and-sensing using microdialysis and biosensing by particle motion for continuous cortisol monitoring

Microdialysis catheters are small probes that allow sampling from biological systems and human subjects with minimal perturbation. Traditionally, microdialysis samples are collected in vials, transported to a laboratory, and analysed with typical turnaround times of hours to days. To realize a continuous sampling-and-sensing methodology with minimal time delay, we studied the integration of microdialysis sampling with a sensor for continuous biomolecular monitoring based on Biosensing by Particle Motion (BPM). A microfluidic flow cell was designed with a volume of 12 μl in order to be compatible with flowrates of microdialysis sampling. The analyte recovery and the time characteristics of the sampling-and-sensing system were studied using a food colorant in buffer and using cortisol in buffer and in blood plasma. Concentration step functions were applied, and the system response was measured using optical absorption and a continuous BPM cortisol sensor. The cortisol recovery was around 80% for a 30 mm microdialysis membrane with a 20 kDa molecular weight cut-off and a flowrate of 2 μl min−1. The concentration-time data could be fitted with a transport delay time and single-exponential relaxation curves. The total delay time of the sampling-and-sensing methodology was about 15 minutes. Continuous sampling-and-sensing was demonstrated over a period of 5 hours. These results represent an important step toward integrated sampling-and-sensing for the continuous monitoring of a wide variety of low-concentration biomolecular substances for applications in biological and biomedical research.</p

Integrated sampling-and-sensing using microdialysis and biosensing by particle motion for continuous cortisol monitoring

Microdialysis catheters are small probes that allow sampling from biological systems and human subjects with minimal perturbation. Traditionally, microdialysis samples are collected in vials, transported to a laboratory, and analysed with typical turnaround times of hours to days. To realize a continuous sampling-and-sensing methodology with minimal time delay, we studied the integration of microdialysis sampling with a sensor for continuous biomolecular monitoring based on Biosensing by Particle Motion (BPM). A microfluidic flow cell was designed with a volume of 12 μl in order to be compatible with flowrates of microdialysis sampling. The analyte recovery and the time characteristics of the sampling-and-sensing system were studied using a food colorant in buffer and using cortisol in buffer and in blood plasma. Concentration step functions were applied, and the system response was measured using optical absorption and a continuous BPM cortisol sensor. The cortisol recovery was around 80% for a 30 mm microdialysis membrane with a 20 kDa molecular weight cut-off and a flowrate of 2 μl min−1. The concentration-time data could be fitted with a transport delay time and single-exponential relaxation curves. The total delay time of the sampling-and-sensing methodology was about 15 minutes. Continuous sampling-and-sensing was demonstrated over a period of 5 hours. These results represent an important step toward integrated sampling-and-sensing for the continuous monitoring of a wide variety of low-concentration biomolecular substances for applications in biological and biomedical research.</p

Determinants of Gray Wolf (Canis lupus) Sightings in Denali National Park

Wildlife viewing within protected areas is an increasingly popular recreational activity. Management agencies are often tasked with providing these opportunities, yet quantitative analyses of factors influencing wildlife sightings are lacking. We analyzed locations of GPS-collared wolves and wolf sightings from 2945 trips in Denali National Park and Preserve, Alaska, USA, to provide a mechanistic understanding of how viewing opportunities are influenced by attributes of wolves and physical, biological, and harvest characteristics. We found that the presence of masking vegetation, den site proximity to the road, pack size, and presence of a wolf harvest closure adjacent to the park affected wolf sightings, and the influence of den proximity on sightings depended on harvest management. Wolf sightings increased with den site proximity to the road in years with a harvest closure adjacent to the park but not in the absence of the closure. The effect of the harvest closure on sightings was similar in magnitude to an increase in pack size by two wolves or a more than a two-fold decrease in masking vegetation. These findings were consistent across a 10-fold change in spatial resolution. Quantitative analysis of the factors influencing wildlife sightings provides valuable insight for agencies tasked with managing viewing opportunities.&nbsp;L’observation de la faune dans les aires protégées est un loisir qui prend de plus en plus d’ampleur. Souvent, les organismes de gestion ont le mandat d’offrir de telles activités et pourtant, il n’y a toujours pas d’analyses quantitatives des facteurs qui exercent une influence sur les observations fauniques. Nous avons analysé les emplacements de loups munis de colliers GPS et les observations de loups découlant de 2 945 déplacements au parc national et à la réserve de Denali, en Alaska, aux États-Unis afin d’obtenir une compréhension mécaniste de la manière dont les activités d’observation sont influencées par les attributs des loups ainsi que par les caractéristiques physiques, biologiques et de récolte. Nous avons remarqué que la présence de végétation masquante, la proximité des tanières de la route, la taille des meutes et la présence d’une interdiction de récolte de loups dans le secteur adjacent au parc ont eu un effet sur les observations de loups, et que l’influence de la proximité des tanières par rapport aux observations dépendait de la gestion des récoltes. Les observations de loups augmentaient en fonction de la proximité des tanières par rapport à la route au cours des années pendant lesquelles il y avait interdiction de récolte de loups dans le secteur adjacent au parc, mais ce n’était pas le cas en l’absence d’interdiction. L’ampleur de l’effet de l’interdiction de récolte sur les observations était semblable à une augmentation de la taille de la meute correspondant à deux loups ou plus, ou à la diminution de plus du double de la végétation masquante. Ces constatations se recoupaient dans un changement correspondant au décuple dans la résolution spatiale. L’analyse quantitative des facteurs influençant les observations fauniques offre une importante perspective aux organismes dont le mandat consiste à gérer les activités d’observation.&nbsp

The connections of the insular VEN area in great apes: A histologically-guided ex vivo diffusion tractography study

We mapped the connections of the insular von Economo neuron (VEN) area in ex vivo brains of a bonobo, an orangutan and two gorillas with high angular resolution diffusion MRI imaging acquired in 36 h imaging sessions for each brain. The apes died of natural causes without neurological disorders. The localization of the insular VEN area was based on cresyl violet-stained histological sections from each brain that were coregistered with structural and diffusion images from the same individuals. Diffusion MRI tractography showed that the insular VEN area is connected with olfactory, gustatory, visual and other sensory systems, as well as systems for the mediation of appetite, reward, aversion and motivation. The insular VEN area in apes is most strongly connected with frontopolar cortex, which could support their capacity to choose voluntarily among alternative courses of action particularly in exploring for food resources. The frontopolar cortex may also support their capacity to take note of potential resources for harvesting in the future (prospective memory). All of these faculties may support insight and volitional choice when contemplating courses of action as opposed to rule-based decision-making

Phosphine Generation Pathways on Rocky Planets

The possibility of life in the venusian clouds was proposed in the 1960s, and recently this hypothesis has been revived with the potential detection of phosphine (PH3) in Venus\u27 atmosphere. These observations may have detected ∼5–20 ppb phosphine on Venus (Greaves et al., 2020), which raises questions about venusian atmospheric/geochemical processes and suggests that this phosphine could possibly be generated by biological processes. In such a claim, it is essential to understand the abiotic phosphorus chemistry that may occur under Venus-relevant conditions, particularly those processes that may result in phosphine generation. Here, we discuss two related abiotic routes for phosphine generation within the atmosphere of Venus. Based on our assessment, corrosion of large impactors as they ablate near Venus\u27 cloud layer, and the presence of reduced phosphorus compounds in the subcloud layer could result in production of phosphine and may explain the phosphine detected in Venus\u27 atmosphere or on other rocky planets. We end on a cautionary note: although there may be life in the clouds of Venus, the detection of a simple, single gas, phosphine, is likely not a decisive indicator

Higher carbohydrate intake is associated with increased risk of allâ cause and diseaseâ specific mortality in head and neck cancer patients: results from a prospective cohort study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145268/1/ijc31413.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145268/2/ijc31413-sup-0001-suppinfo01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145268/3/ijc31413_am.pd

Accurate Estrogen Receptor Quantification in Patients with Negative and Low-Positive Estrogen-Receptor-Expressing Breast Tumors: Sub-Analyses of Data from Two Clinical Studies

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