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"Pietsch, J."
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Settling velocities of coarse organic solids
2023
The settling velocity of a particle is an integral parameter in stormwater modeling and design. The settling velocity can be used to predict the fate and transport of stormwater particles and if the particles contribute to nutrient loading in a watershed. Prediction of settling velocity for inorganic particles is generally well-researched and well-understood. Organic particles tend to vary widely in their physical properties and there are currently no set standards or empirical equations for estimating the settling velocity of organic particles. This paper presents data from tree leaves and seeds settling velocity experiments to better understand how organic particles settle in the context of settling velocity equations such as the one developed by Ferguson and Church. Analysis of the collected data showed that the second of the two drag coefficients (C
2
) used in the Ferguson and Church Equation was sensitive to particle type and shape. By averaging C
2
by particle type and species, there was a correlation between the observed settling velocity and the settling velocity predicted by the Ferguson and Church Equation (R
2
= 0.83). With these results, stormwater modelers and designers are equipped with a better understanding of how to represent common organic particles in terms of settling velocity. Additional research on a wider variety of organic particle types and species would expand on the dataset presented here.
Journal Article
Distributed and dynamic intracellular organization of extracellular information
by
Tkačik, Gǎsper
,
Pietsch, Julian M. J.
,
Cepeda-Humerez, Sarah A.
in
Biological Sciences
,
Coding
,
Decision making
2018
Although cells respond specifically to environments, how environmental identity is encoded intracellularly is not understood. Here, we study this organization of information in budding yeast by estimating the mutual information between environmental transitions and the dynamics of nuclear translocation for 10 transcription factors. Our method of estimation is general, scalable, and based on decoding from single cells. The dynamics of the transcription factors are necessary to encode the highest amounts of extracellular information, and we show that information is transduced through two channels: Generalists (Msn2/4, Tod6 and Dot6, Maf1, and Sfp1) can encode the nature of multiple stresses, but only if stress is high; specialists (Hog1, Yap1, and Mig1/2) encode one particular stress, but do so more quickly and for a wider range of magnitudes. In particular, Dot6 encodes almost as much information as Msn2, the master regulator of the environmental stress response. Each transcription factor reports differently, and it is only their collective behavior that distinguishes between multiple environmental states. Changes in the dynamics of the localization of transcription factors thus constitute a precise, distributed internal representation of extracellular change. We predict that such multidimensional representations are common in cellular decision-making.
Journal Article
Three fatalities associated with the synthetic cannabinoids 5F-ADB, 5F-PB-22, and AB-CHMINACA
2017
[Display omitted]
•Three case reports in the context of synthetic cannabinoids are presented.•Post mortem femoral blood concentrations are reported.•Femoral blood concentrations cannot be correlated directly with the cause of death.•Every fatality involving synthetic cannabinoids should be assessed on a case by case basis.
The use of synthetic cannabinoids (SC) has been widespread in certain groups of drug users for many years. In the scientific literature many intoxication cases and a number of fatalities after the use of synthetic cannabinoids were reported. In this paper three death cases are described with involvement of the synthetic cannabinoids 5F-PB-22, AB-CHMINACA, and 5F-ADB. The three cases occurred in the eastern region of Germany, which is known as a region of high methamphetamine abuse. All decedents were male, between 25 and 41 years old, and had a known history of drug use. Femoral blood concentrations of the synthetic cannabinoids were measured using a validated LC–MS/MS method. The concentration of 5F-PB-22 in the first case was 0.37ng/mL, the concentration of AB-CHMINACA in the second case was approximately 4.1ng/mL (extrapolated) and the 5F-ADB concentration in the third case was 0.38ng/mL. Compared to other published cases the concentrations in the here presented cases seem to be in the lower range. However, taking into account the scene of death, the results of the forensic autopsy and the full toxicological analysis, the deaths can be explained as a direct consequence of consumption of synthetic cannabinoids, although in case one and two relevant amounts of ethanol were found, and in case three trimipramine and olanzapine were present in non-toxic concentrations. It has to be noted that concentrations of synthetic cannabinoids in femoral blood cannot directly be judged as toxic or lethal due to the possibility of postmortem redistribution and the development of tolerance after frequent use. Therefore, all available information has to be considered carefully before stating SC use as the cause of death.
Journal Article
Context-dependent adaption of EpCAM expression in early systemic esophageal cancer
2014
The role of the epithelial cell adhesion molecule EpCAM in cancer progression remains largely unclear. High expression of EpCAM in primary tumors is often associated with more aggressive phenotypes and EpCAM is the prime epithelial antigen in use to isolate circulating tumor cells (CTCs) and characterize disseminated tumor cells (DTCs). However, reduced expression of EpCAM was associated with epithelial-to-mesenchymal transition (EMT) and reports on a lack of EpCAM on CTCs emerged. These contradictory observations might reflect a context-dependent adaption of EpCAM expression during metastatic progression. To test this, EpCAM expression was monitored in esophageal cancer at different sites of early systemic disease. Although most of the primary esophageal tumors expressed high levels of EpCAM, the majority of DTCs in bone marrow lacked EpCAM.
In vitro
, downregulation of EpCAM expression at the plasma membrane was observed in migrating and invading cells, and was associated with a partial loss of the epithelial phenotype and with significantly decreased proliferation. Accordingly, induction of EMT through the action of TGFβ resulted in substantial loss of EpCAM cell surface expression on esophageal cancer cells. Knock-down or natural loss of EpCAM recapitulated these effects as it reduced proliferation while enhancing migration and invasion of cancer cells. Importantly, expression of EpCAM on DTCs was significantly associated with the occurrence of lymph node metastases and with significantly decreased overall survival of esophageal cancer patients. We validated this observation by showing that high expression of EpCAM promoted tumor outgrowth after xenotransplantation of esophageal carcinoma cells. The present data disclose a dynamic expression of EpCAM throughout tumor progression, where EpCAM
high
phenotypes correlate with proliferative stages, whereas EpCAM
low/negative
phenotypes associated with migration, invasion and dissemination. Thus, differing expression levels of EpCAM must be taken into consideration for therapeutic approaches and during clinical retrieval of disseminated tumor cells.
Journal Article
Determining growth rates from bright-field images of budding cells through identifying overlaps
by
Swain, Peter S
,
Adjavon, Diane-Yayra A
,
Muñoz, Alán F
in
Algorithms
,
budding cells
,
Cell Biology
2023
Much of biochemical regulation ultimately controls growth rate, particularly in microbes. Although time-lapse microscopy visualises cells, determining their growth rates is challenging, particularly for those that divide asymmetrically, like Saccharomyces cerevisiae , because cells often overlap in images. Here, we present the Birth Annotator for Budding Yeast (BABY), an algorithm to determine single-cell growth rates from label-free images. Using a convolutional neural network, BABY resolves overlaps through separating cells by size and assigns buds to mothers by identifying bud necks. BABY uses machine learning to track cells and determine lineages and estimates growth rates as the rates of change of volumes. Using BABY and a microfluidic device, we show that bud growth is likely first sizer- then timer-controlled, that the nuclear concentration of Sfp1, a regulator of ribosome biogenesis, varies before the growth rate does, and that growth rate can be used for real-time control. By estimating single-cell growth rates and so fitness, BABY should generate much biological insight.
Journal Article
Transition between fermentation and respiration determines history-dependent behavior in fluctuating carbon sources
by
Jariani, Abbas
,
Gallone, Brigida
,
Cerulus, Bram
in
Aerobiosis - drug effects
,
Biology
,
Carbohydrates - pharmacology
2018
Cells constantly adapt to environmental fluctuations. These physiological changes require time and therefore cause a lag phase during which the cells do not function optimally. Interestingly, past exposure to an environmental condition can shorten the time needed to adapt when the condition re-occurs, even in daughter cells that never directly encountered the initial condition. Here, we use the molecular toolbox of Saccharomyces cerevisiae to systematically unravel the molecular mechanism underlying such history-dependent behavior in transitions between glucose and maltose. In contrast to previous hypotheses, the behavior does not depend on persistence of proteins involved in metabolism of a specific sugar. Instead, presence of glucose induces a gradual decline in the cells’ ability to activate respiration, which is needed to metabolize alternative carbon sources. These results reveal how trans-generational transitions in central carbon metabolism generate history-dependent behavior in yeast, and provide a mechanistic framework for similar phenomena in other cell types.
Journal Article
Tracking cats: problems with placing feline carnivores on δO, δD isoscapes
by
Hobson, Keith A
,
Pietsch, Stephanie J
,
Tütken, Thomas
in
Amino Acids - chemistry
,
Animals
,
Body Water
2011
Several felids are endangered and threatened by the illegal wildlife trade. Establishing geographic origin of tissues of endangered species is thus crucial for wildlife crime investigations and effective conservation strategies. As shown in other species, stable isotope analysis of hydrogen and oxygen in hair (δD(h), δ(18)O(h)) can be used as a tool for provenance determination. However, reliably predicting the spatial distribution of δD(h) and δ(18)O(h) requires confirmation from animal tissues of known origin and a detailed understanding of the isotopic routing of dietary nutrients into felid hair.
We used coupled δD(h) and δ(18)O(h) measurements from the North American bobcat (Lynx rufus) and puma (Puma concolor) with precipitation-based assignment isoscapes to test the feasibility of isotopic geo-location of felidae. Hairs of felid and rabbit museum specimens from 75 sites across the United States and Canada were analyzed. Bobcat and puma lacked a significant correlation between H/O isotopes in hair and local waters, and also exhibited an isotopic decoupling of δ(18)O(h) and δD(h). Conversely, strong δD and δ(18)O coupling was found for key prey, eastern cottontail rabbit (Sylvilagus floridanus; hair) and white-tailed deer (Odocoileus virginianus; collagen, bone phosphate).
Puma and bobcat hairs do not adhere to expected pattern of H and O isotopic variation predicted by precipitation isoscapes for North America. Thus, using bulk hair, felids cannot be placed on δ(18)O and δD isoscapes for use in forensic investigations. The effective application of isotopes to trace the provenance of feline carnivores is likely compromised by major controls of their diet, physiology and metabolism on hair δ(18)O and δD related to body water budgets. Controlled feeding experiments, combined with single amino acid isotope analysis of diets and hair, are needed to reveal mechanisms and physiological traits explaining why felid hair does not follow isotopic patterns demonstrated in many other taxa.
Journal Article
Red blood cell transfusion volume and mortality among patients receiving extracorporeal membrane oxygenation
by
Smith, AH
,
Bridges, BC
,
Hardison, DC
in
Erythrocyte Transfusion - mortality
,
Extracorporeal Membrane Oxygenation - mortality
,
Female
2013
Background:
Red blood cell (RBC) transfusion is used in the critically ill with low hemoglobin concentrations to optimize oxygen utilization and delivery imbalance. Data suggest that RBC transfusion is also independently associated with significant morbidity. We seek to characterize RBC transfusion volumes among patients receiving extracorporeal membrane oxygenation (ECMO) support and test the hypothesis that red blood cell transfusion volume is an independent risk factor for mortality.
Methods:
Records of all patients receiving ECMO support from 2001 through 2010 at a university-affiliated children’s hospital were retrospectively reviewed.
Results:
Among 484 ECMO runs reviewed, indications for ECMO were classified as cardiac (40%), non-cardiac (42%) or institution of ECMO during cardiopulmonary resuscitation (CPR) (18%). Median duration of ECMO support was 4.6 days, with overall survival to hospital discharge significantly higher among non-cardiac patients (60%) relative to patients supported for cardiac (37%) or external CPR (ECPR) indications (34%, p<0.001). Median RBC transfusion volumes with respect to ECMO indication were significantly greater among cardiac (105 mL/kg/day ECMO) and ECPR patients (66 mL/kg/day ECMO) relative to patients supported for non-cardiac indications (20 mL/kg/day ECMO, p<0.001). Among patients supported with ECMO for non-cardiac indications alone (n=203), independent of covariates, including weight, venoarterial mode of ECMO support, presence of congenital diaphragmatic hernia and complications, including hemorrhage, neurologic injury, and renal insufficiency, each RBC transfusion volume of 10 mL/kg/day ECMO was associated with a 24% increase in the odds of in-hospital mortality (OR 1.024, 95% CI 1.004-1.046, p=0.018).
Conclusions:
Greater red blood cell transfusion volumes among patients supported with ECMO for non-cardiac indications are independently associated with an increase in odds of mortality. A prospective investigation of restrictive RBC transfusion practices while receiving ECMO may be warranted in this population.
Journal Article
Escalation of methamphetamine-related crime and fatalities in the Dresden region, Germany, between 2005 and 2011
by
Paulick, T.
,
Pietsch, J.
,
Engel, A.
in
Adult
,
Amphetamine-Related Disorders - blood
,
Amphetamine-Related Disorders - epidemiology
2013
Methamphetamine (MA), a central nervous system stimulating recreational drug, is a worldwide problem related to crime as well as forensic and health aspects.
The data, exemplarily presented in this study for the Dresden region, Saxony, Germany, demonstrate the escalation of MA-related crime and fatalities between 2005 and 2011.
Easy availability and an attractive price of MA in the Czech Republic are responsible for both the increase of the occurrence of MA in relation to the entire drug crime as well as the increase of the occurrence of MA-positive cases of driving under influence (DUI).
Higher percentage of very pure MA on the Saxon drug market since 2010 seems to be the reason for the fatalities directly caused by MA in 2010 and 2011.
Journal Article
The Victorian Active Script Programme: promising signs for general practitioners, population health, and the promotion of physical activity
2004
Background: The Active Script Programme (ASP) aimed to increase the number of general practitioners (GPs) in Victoria, Australia who deliver appropriate, consistent, and effective advice on physical activity to patients. To maximise GP participation, a capacity building strategy within Divisions of General Practice (DGPs) was used. The objectives of the programme were to (a) train and support GPs in advising sedentary patients, and (b) develop tools and resources to assist GPs. Objective: To evaluate the effectiveness of the ASP. Methods: A systems approach was used to promote capacity in Victorian general practice. Economic analyses were incorporated into the programme’s evaluation. Participants were selected DGPs and their GP members. The programme worked with DGPs to train GPs and provide relevant resources. The main outcome measures were (a) changes in GP knowledge and behaviour and (b) cost effectiveness, based on modelled estimates of numbers of patients advised and adopting physical activity and gaining the associated health benefits. Results: GP awareness and provision of physical activity advice increased. Although the programme’s reach was modest, based on actual GP involvement, the cost effectiveness figures ($138 per patient to become sufficiently active to gain health benefits, and $3647 per disability adjusted life year saved) are persuasive. Conclusions: The ASP increased DGPs’ capacity to support GPs to promote physical activity. There is a strong economic argument for governments to invest in such programmes. However, caution is warranted about the maintenance of patients’ activity levels. Programme refinement to encourage GPs to use community supports more effectively will guide future development. Further research on long term patient adherence through a multisectorial approach is warranted.
Journal Article