Ökologische Bewertung des Risikos von Charophytenverlusten unter ökotoxikologischem Stress in einem mesotrophen See

In Seen treten ebenso wie in Fließgewässern regelmäßig erhebliche Effekte auf, die es nach Umweltqualitätsnormen (UQN) nicht geben dürfte, auch wenn es im konkreten Fall keinen vernünftigen Zweifel an einem ursächlichen Zusammenhang mit diffusen Einträgen von Xenobiotika gibt (Krambeck 2019, 2020, Liess & vd Ohe 2005). Dass reale Risiken unterschätzt werden, ist darauf zurückzuführen, dass die regulatorisch zu postulierende Standardisierung von UQN und Reproduzierbarkeit von Effekten der Komplexität von Ökosystemen nicht gerecht werden kann. Die Notwendigkeit, diesen Widerspruch aufzulösen, ist imKontext mit Fließgewässern häufig thematisiert worden, das Problem bisher aber nicht gelöst, mit der Folge, dass Ziele wie Artenschutz mit über UQN definiertem Handlungsbedarf verfehlt werden. Es soll gezeigt werden, dass sich auf der Grundlage des geradebei Seen soliden Wissens um ökosystemare Zusammenhänge neue Wege der Erkennung und Interpretation von ökotoxikologischen Störungen eröffnen, sich daraus Möglichkeiten einer pragmatischen, d.h. an Plausibilität orientierten und auf sinnvolle Maßnahmen weisenden Risikobewertung ergeben und dass eine Rückkoppelung an regulatorische Routinen möglich ist

Understanding, justifying, and optimizing radiation exposure for CT imaging in nephrourology

An estimated 4-5 million CT scans are performed in the USA every year to investigate nephrourological diseases such as urinary stones and renal masses. Despite the clinical benefits of CT imaging, concerns remain regarding the potential risks associated with exposure to ionizing radiation. To assess the potential risk of harmful biological effects from exposure to ionizing radiation, understanding the mechanisms by which radiation damage and repair occur is essential. Although radiation level and cancer risk follow a linear association at high doses, no strong relationship is apparent below 100 mSv, the doses used in diagnostic imaging. Furthermore, the small theoretical increase in risk of cancer incidence must be considered in the context of the clinical benefit derived from a medically indicated CT and the likelihood of cancer occurrence in the general population. Elimination of unnecessary imaging is the most important method to reduce imaging-related radiation; however, technical aspects of medically justified imaging should also be optimized, such that the required diagnostic information is retained while minimizing the dose of radiation. Despite intensive study, evidence to prove an increased cancer risk associated with radiation doses below ~100 mSv is lacking; however, concerns about ionizing radiation in medical imaging remain and can affect patient care. Overall, the principles of justification and optimization must remain the basis of clinical decision-making regarding the use of ionizing radiation in medicine

Characterization of a Copper Powder for Heat Pipe Wick Applications

In powder metallurgy, it is necessary to know the powder's nature to understand how the processing of a powder occurs. In this paper, a characterization of a copper powder for heat pipe wick applications was experimentally done. The copper powder manufacturing method was atomization. This metallic powder was characterized by Scanning Electron Microscopy (SEM), X-Ray Fluorescence Spectrometry (ED-XRF), and Laser Diffraction Granulometry. As a result, the purity and the shape are compatible with the powder manufacturing method and great for wicks. Also, the copper powder has a unimodal distribution that is excellent for capillary structures

Therapeutic Peptides and Proteins: Stabilization Challenges and Biomedical Applications by Means of Nanodelivery Systems

The delivery of peptides and proteins usually faces formulation development challenges attributed to the difficulties encountered in their stabilization. Nanoparticles offer an alternative to improve the physicochemical stability of such biomacromolecules, while increasing their bioavailability by overcoming biological absorption barriers. With this review, we aim to discuss the stability problems of proteins and peptides that have driven the scientific community to find in nanotechnology a valid alternative for oral administration of biomolecules. In addition, we describe the most commonly used nanoparticles for this purpose (e.g., polymers such as polylactic acid, poly(lactic-co-glycolic acid), polycaprolactone, modified chitosan, and lipids such as oil-in-water nanoemulsions, self-emulsified drug delivery systems, solid lipid nanoparticles, nanostructured lipid carriers, liposomes, as well as hybrid systems like micelles), and we show some of the most important recent applications of these nanoparticles for the delivery of proteins and peptides, including for the treatment of diabetes, viruses (such as HIV), cancer, as well as in the development of vaccines

Imaging in Suspected Renal Colic: Systematic Review of the Literature and Multispecialty Consensus

Background Renal colic is common, and CT is frequently utilized when the diagnosis of kidney stones is suspected. CT is accurate but exposes patients to ionizing radiation and has not been shown to alter either interventional approaches or hospital admission rates. This multi-organizational transdisciplinary collaboration sought evidence-based, multispecialty consensus on optimal imaging across different clinical scenarios in patients with suspected renal colic in the acute setting. Methods In conjunction with the American College of Emergency Physicians (ACEP) eQual network, we formed a nine-member panel with three physician representatives each from ACEP, the ACR, and the American Urology Association. A systematic literature review was used as the basis for a three-step modified Delphi process to seek consensus on optimal imaging in 29 specific clinical scenarios. Results From an initial search yielding 6,337 records, there were 232 relevant articles of acceptable evidence quality to guide the literature summary. At the completion of the Delphi process consensus, agreement was rated as perfect in 15 (52%), excellent in 8 (28%), good in 3 (10%), and moderate in 3 (10%) of the 29 scenarios. There were no scenarios where at least moderate consensus was not reached. CT was recommended in 7 scenarios (24%), with ultrasound in 9 (31%) and no further imaging needed in 12 (45%). Summary Evidence and multispecialty consensus support ultrasound or no further imaging in specific clinical scenarios, with reduced-radiation dose CT to be employed when CT is needed in patients with suspected renal colic

Centralized Modularity of N-Linked Glycosylation Pathways in Mammalian Cells

Glycosylation is a highly complex process to produce a diverse repertoire of cellular glycans that are attached to proteins and lipids. Glycans are involved in fundamental biological processes, including protein folding and clearance, cell proliferation and apoptosis, development, immune responses, and pathogenesis. One of the major types of glycans, N-linked glycans, is formed by sequential attachments of monosaccharides to proteins by a limited number of enzymes. Many of these enzymes can accept multiple N-linked glycans as substrates, thereby generating a large number of glycan intermediates and their intermingled pathways. Motivated by the quantitative methods developed in complex network research, we investigated the large-scale organization of such N-linked glycosylation pathways in mammalian cells. The N-linked glycosylation pathways are extremely modular, and are composed of cohesive topological modules that directly branch from a common upstream pathway of glycan synthesis. This unique structural property allows the glycan production between modules to be controlled by the upstream region. Although the enzymes act on multiple glycan substrates, indicating cross-talk between modules, the impact of the cross-talk on the module-specific enhancement of glycan synthesis may be confined within a moderate range by transcription-level control. The findings of the present study provide experimentally-testable predictions for glycosylation processes, and may be applicable to therapeutic glycoprotein engineering

Reachability in Biochemical Dynamical Systems by Quantitative Discrete Approximation (extended abstract)

In this paper, a novel computational technique for finite discrete approximation of continuous dynamical systems suitable for a significant class of biochemical dynamical systems is introduced. The method is parameterized in order to affect the imposed level of approximation provided that with increasing parameter value the approximation converges to the original continuous system. By employing this approximation technique, we present algorithms solving the reachability problem for biochemical dynamical systems. The presented method and algorithms are evaluated on several exemplary biological models and on a real case study.Comment: In Proceedings CompMod 2011, arXiv:1109.104

B7-H4 Treatment of T Cells Inhibits ERK, JNK, p38, and AKT Activation

B7-H4 is a newly identified B7 homolog that plays an important role in maintaining T-cell homeostasis by inhibiting T-cell proliferation and lymphokine-secretion. In this study, we investigated the signal transduction pathways inhibited by B7-H4 engagement in mouse T cells. We found that treatment of CD3+ T cells with a B7-H4.Ig fusion protein inhibits anti-CD3 elicited T-cell receptor (TCR)/CD28 signaling events, including phosphorylation of the MAP kinases, ERK, p38, and JNK. B7-H4.Ig treatment also inhibited the phosphorylation of AKT kinase and impaired its kinase activity as assessed by the phosphorylation of its endogenous substrate GSK-3. Expression of IL-2 is also reduced by B7-H4. In contrast, the phosphorylation state of the TCR proximal tyrosine kinases ZAP70 and lymphocyte-specific protein tyrosine kinase (LCK) are not affected by B7-H4 ligation. These results indicate that B7-H4 inhibits T-cell proliferation and IL-2 production through interfering with activation of ERK, JNK, and AKT, but not of ZAP70 or LCK