Dynamics of Perfectly Wetting Drops under Gravity

We study the dynamics of small droplets of polydimethylsiloxane (PDMS) silicone oil on a vertical, perfectly-wetting, silicon wafer. Interference videomicroscopy allows us to capture the dynamics of these droplets. We use droplets with a volumes typically ranging from 100 to 500 nanolitres (viscosities from 10 to 1000 centistokes) to understand long time derivations from classical solutions. Past researchers used one dimensional theory to understand the typical $t^{1/3}$ scaling for the position of the tip of the droplet in time $t$. We observe this regime in experiment for intermediate times and discover a two-dimensional, similarity solution of the shape of the droplet. However, at long times our droplets start to move more slowly down the plane than the $t^{1/3}$ scaling suggests and we observe deviations in droplet shape from the similarity solution. We match experimental data with simulations to show these deviations are consistent with retarded van der Waals forcing which should become significant at the small heights observed

Severity of depression and hypothalamic-pituitary-adrenal axis dysregulation: identification of contributing factors

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65507/1/j.1600-0447.1990.tb05465.x.pd

The embryonic thermal environment has positive but weak effects on thermal tolerance later in life in the aquatic invertebrate Gammarus chevreuxi

Recent evidence suggests that the adult phenotype is influenced by temperatures experienced in early life. However, our understanding of the extent to which the embryonic environment can modulate thermal tolerance later in life is limited, owing to the paucity of studies with appropriate experimental designs to test for this form of developmental plasticity. We investigated whether the thermal environment experienced during embryonic development affects thermal limits in later life. Embryos of the estuarine amphipod Gammarus chevreuxi were incubated until hatching to 15 °C, 20 °C and 25 °C, then reared under a common temperature. Using thermal ramping assays, we determined upper thermal limits in juveniles, four weeks post-hatch. Individuals exposed to higher temperatures during embryonic development displayed greater thermal tolerance as juveniles (acclimation response ratio ≈ 0.10-0.25 for upper lethal temperature). However, we suggest that the degree of developmental plasticity observed is limited, and will provide little benefit under future climate change scenarios

Plasma postdexamethasone cortisol levels in schizoaffective disorder

The degree of hypothalamic-pituitary-adrenal (HPA) axis dysregulation in depressed patients with schizoaffective disorder was compared to that seen in patients with major depressive disorder with and without delusional features. The frequency of nonsuppression to dexamethasone was similar for all three diagnostic groups. Maximum postdexamethasone plasma cortisol was greater for delusional depressives, but did not differ between patients with major depressive and schizoaffective disorders. Modest correlations were found between postdexamethasone plasma cortisol levels, severity of illness, age, and recent weight loss, for patients with both major depressive disorder and delusional depression. For schizoaffective patients, associations between postdexamethasone plasma cortisol levels and various measures of severity of illness, but not age and recent weight loss, were found. Although HPA axis dysregulation occurs more frequently in all three of the studied diagnostic groups than in normal individuals, factors contributing to this dysregulation may be qualitatively different for schizoaffective patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27102/1/0000094.pd

Revamping AI Models in Dermatology: Overcoming Critical Challenges for Enhanced Skin Lesion Diagnosis

The surge in developing deep learning models for diagnosing skin lesions through image analysis is notable, yet their clinical black faces challenges. Current dermatology AI models have limitations: limited number of possible diagnostic outputs, lack of real-world testing on uncommon skin lesions, inability to detect out-of-distribution images, and over-reliance on dermoscopic images. To address these, we present an All-In-One \textbf{H}ierarchical-\textbf{O}ut of Distribution-\textbf{C}linical Triage (HOT) model. For a clinical image, our model generates three outputs: a hierarchical prediction, an alert for out-of-distribution images, and a recommendation for dermoscopy if clinical image alone is insufficient for diagnosis. When the recommendation is pursued, it integrates both clinical and dermoscopic images to deliver final diagnosis. Extensive experiments on a representative cutaneous lesion dataset demonstrate the effectiveness and synergy of each component within our framework. Our versatile model provides valuable decision support for lesion diagnosis and sets a promising precedent for medical AI applications

Dexamethasone suppression test status and severity of depression

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27129/1/0000122.pd

Multiplicity of depressive episodes: Phenomenological and neuroendocrine correlates

Sixty-four patients with a Research Diagnostic Criteria (RDC) diagnosis of major depressive disorder were categorized into three groups based on their number of depressive episodes (DE): Gr 1 (1 DE), n = 16, Gr II (2-4 DE), n = 25; and Gr III (5 or more DE), n = 23. All patients were nonsuppressors after 1 mg dexamethasone suppression test (DST) prior to the start of treatment. Patients were monitored during the course of their treatment using serial Hamilton Depression scores and post-DST plasma cortisol levels. A proportionately equal number of patients in the three groups had a favorable outcome, i.e., the number of depressive episodes did not predict recovery. Despite favorable clinical outcome, patients with higher numbers of depressive episodes had significantly higher post-DST plasma cortisol levels that were above the supressive range (greater than 5 [mu]g/dl). Patients with a higher number of depressive episodes had a significantly shorter duration of index episodes and were younger at first depressive episode than patients in the other two groups. These results, however, were confounded with polarity, with a higher number of bipolars in Gr III than in the other two groups. Results are discussed in light of phenomenological and psychoendocrine findings of earlier studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28571/1/0000374.pd

Multiple depressive episodes and plasma postdexamethasone cortisol levels

The hypothalamic-pituitary-adrenal (HPA) axis is dysregulated in many patients with major depressive disorder (MDD). To determine whether or not a past history of depressive episodes is associated with this dysregulation, we studied the relationships among number of past depressive episodes, number of previous hospitalizations for depression, and number of years since first depressive episode and biological markers of depression (postdexamethasone plasma cortisol levels and dexamethasone suppressor/nonsuppressor status). No significant relationships were detected.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26723/1/0000273.pd

Postdexamethasone plasma cortisol and [beta]-endorphin levels in depression: Relationship to severity of illness

The hypothalamic-pituitary-adrenal (HPA) axis is dysregulated in many patients with depression, probably at all levels of the axis. To determine if HPA dysregulation is associated with severity of depression, we studied a group of 66 patients with major depressive disorder. Each patient underwent a pretreatment Dexamethasone Suppression Test, with plasma postdexamethasone cortisol determination at 8:00 AM, 4:00 PM, and 11:00 PM. All three postdexamethasone cortisol levels were significantly correlated with the Hamilton Rating Scale for Depression (HRSD) scores. We also examined the "profile" measures of mean, maximum, and minimum of the three cortisol values; again, all three were significantly correlated with HRSD scores. To evaluate associations between clinical severity and HPA dysregulation at the pituitary level, we studied a second group of 44 patients with major depressive disorder. Each had postdexamethasone cortisol determinations at 4:00 PM and 11:00 PM as well as pre- and postdexamethasone [beta]-endorphin determinations at 4:00 PM. The cortisol data from this group followed the same pattern as in the first sample, and there was a significant relationship between HRSD score and degree of [beta]-endorphin nonsuppression as well. These results suggest that severity of depression is one of the determinants of dysregulation at both adrenal and pituitary levels of the HPA axis, accounting for 10%-20% of the observed variance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26603/1/0000144.pd

Circadian hormone secretory profiles in women with severe premenstrual tension syndrome.

The circadian secretory profiles of serum prolactin, growth hormone and cortisol were measured in two women suffering from severe premenstrual tension syndrome and in two asymptomatic control subjects. Subjects and controls were screened and included after a rigorous selection process. Blood samples were obtained every 30 min over a period of 24 h in each woman both on day 9 (follicular phase) and day 26 (luteal phase) of the menstrual cycle. There was no relationship between the hormonal secretory profiles and the premenstrual tension syndrome.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75119/1/j.1471-0528.1984.tb04785.x.pd