Mathematiklehrkräfte und -fortbildende reflektieren die Nutzung eines Chatbots zur Vorbereitung einer schulpraktischen Erprobung innovativer Lernumgebungen

Dieser Beitrag stellt die qualitative Evaluation eines Chatbots als innovatives Fortbildungsmaterial zur Unterstützung schulpraktischer Erprobungen – also Phasen situierten Lernens von Lehrkräften – in den Mittelpunkt. Dazu werden überblicksartig die Hintergründe, der bisherige Entwicklungsprozess, der methodische Rahmen sowie erste Ergebnisse der Evaluation dargestellt

AROMATHERAPY AS AN ADJUVANT TREATMENT IN CANCER CARE – A DESCRIPTIVE SYSTEMATIC REVIEW

Claims of benefits of aromatherapy for cancer patients include reduced anxiety levels and relief of emotional stress, pain, muscular tension and fatigue. The objective of this paper is to provide an updated descriptive, systematic review of evidence from pre-clinical and clinical trials assessing the benefits and safety of aromatherapy for cancer patients. Literature databases such as Medline (via Ovid), the Cochrane database of systematic reviews, Cochrane Central were searched from their inception until October 2010. Only studies on cancer cells or cancer patients were included. There is no long lasting effect of aromatherapy massage, while short term improvements were reported for general well being, anxiety and depression up to 8 weeks after treatment. The reviewed studies indicate short-term effects of aromatherapy on depression, anxiety and overall wellbeing. Specifically, some clinical trials found an increase in patient-identified symptom relief, psychological wellbeing and improved sleep. Furthermore, some found a short-term improvement (up to 2 weeks after treatment) in anxiety and depression scores and better pain control. Although essential oils have generally shown minimal adverse effects, potential risks include ingesting large amounts (intentional misuse); local skin irritation, especially with prolonged skin contact; allergic contact dermatitis; and phototoxicity from reaction to sunlight (some oils). Repeated topical administration of lavender and tea tree oil was associated with reversible prepubertal gynecomastia

Nucleotide exchange and excision technology (NExT) DNA shuffling: a robust method for DNA fragmentation and directed evolution

DNA shuffling is widely used for optimizing complex properties contained within DNA and proteins. Demonstrated here is the amplification of a gene library by PCR using uridine triphosphate (dUTP) as a fragmentation defining exchange nucleotide with thymidine, together with the three other nucleotides. The incorporated uracil bases were excised using uracil-DNA-glycosylase and the DNA backbone subsequently cleaved with piperidine. These end-point reactions required no adjustments. Polyacrylamide urea gels demonstrated adjustable fragmentation size over a wide range. The oligonucleotide pool was reassembled by internal primer extension to full length with a proofreading polymerase to improve yield over Taq. We present a computer program that accurately predicts the fragmentation pattern and yields all possible fragment sequences with their respective likelihood of occurrence, taking the guesswork out of the fragmentation. The technique has been demonstrated by shuffling chloramphenicol acetyltransferase gene libraries. A 33% dUTP PCR resulted in shuffled clones with an average parental fragment size of 86 bases even without employment of a fragment size separation, and revealed a low mutation rate (0.1%). NExT DNA fragmentation is rational, easily executed and reproducible, making it superior to other techniques. Additionally, NExT could feasibly be applied to several other nucleotide analogs

Perinatal mortality in German dairy cattle: Unveiling the importance of cow-level risk factors and their interactions using a multifaceted modelling approach

Perinatal mortality (PM) is a common issue on dairy farms, leading to calf losses and increased farming costs. The current knowledge about PM in dairy cattle is, however, limited and previous studies lack comparability. The topic has also primarily been studied in Holstein-Friesian cows and closely related breeds, while other dairy breeds have been largely ignored. Different data collection techniques, definitions of PM, studied variables and statistical approaches further limit the comparability and interpretation of previous studies. This article aims to investigate the factors contributing to PM in two underexplored breeds, Simmental (SIM) and Brown Swiss (BS), while comparing them to German Holstein on German farms, and to employ various modelling techniques to enhance comparability to other studies, and to determine if different statistical methods yield consistent results. A total of 133,942 calving records from 131,657 cows on 721 German farms were analyzed. Amongst these, the proportion of PM (defined as stillbirth or death up to 48 hours of age) was 6.1%. Univariable and multivariable mixed-effects logistic regressions, random forest and multimodel inference via brute-force model selection approaches were used to evaluate risk factors on the individual animal level. Although the balanced random forest did not incorporate the random effect, it yielded results similar to those of the mixed-effect model. The brute-force approach surpassed the widely adopted backwards variable selection method and represented a combination of strengths: it accounted for the random effect similar to mixed-effects regression and generated a variable importance plot similar to random forest. The difficulty of calving, breed and parity of the cow were found to be the most important factors, followed by farm size and season. Additionally, four significant interactions amongst predictors were identified: breed—calving ease, breed—season, parity—season and calving ease—farm size. The combination of factors, such as secondiparous SIM breed on small farms and experiencing easy calving in summer, showed the lowest probability of PM. Conversely, primiparous GH cows on large farms with difficult calving in winter exhibited the highest probability of PM. In order to reduce PM, appropriate management of dystocia, optimal heifer management and a wider use of SIM in dairy production are possible ways forward. It is also important that future studies are conducted to identify farm-specific contributors to higher PM on large farms

Novel methods for in vitro modeling of pancreatic cancer reveal important aspects for successful primary cell culture

Background: Pancreatic cancer remains a fatal disease. Experimental systems are needed for personalized treatment strategies, drug testing and to further understand tumor biology. Cell cultures can serve as an excellent preclinical platform, but their generation remains challenging. Methods: Tumor cells from surgically removed pancreatic ductal adenocarcinoma (PDAC) specimens were cultured under novel protocols. Cellular growth and composition were analyzed and culture conditions were continuously optimized. Characterization of cell cultures and primary tumors was performed via hematoxylin and eosin (HE) and immunofluorescence (IF) staining. Results: Protocols for two- and three-dimensional PDAC primary cell cultures could successfully be established. Primary cell culture depended on dissociation techniques, growth factor supplementation and extracellular matrix components containing Matrigel being crucial for the transformation to three-dimensional PDAC organoids. The generated cultures showed to be highly resemblant to established PDAC primary cell cultures. HE and IF staining for cell culture and corresponding primary tumor characterization could successfully be performed. Conclusions: The work presented herein shows novel and effective methods to successfully establish primary PDAC cell cultures in a distinct time frame. Factors contributing to cell growth and differentiation could be identified with important implications for further primary cell culture protocols. The established protocols might serve as novel tools in personalized tumor therapy

Mass Spectrometry of RNA-Binding Proteins during Liquid-Liquid Phase Separation Reveals Distinct Assembly Mechanisms and Droplet Architectures

Liquid-liquid phase separation (LLPS) of hetero-geneous ribonucleoproteins (hnRNPs) drives the formation of membraneless organelles, but structural information about their assembled states is still lacking. Here, we address this challenge through a combination of protein engineering, native ion mobility mass spectrometry, and molecular dynamics simulations. We used an LLPS-compatible spider silk domain and pH changes to control the self-assembly of the hnRNPs FUS, TDP-43, and hCPEB3, which are implicated in neurodegeneration, cancer, and memory storage. By releasing the proteins inside the mass spectrometer from their native assemblies, we could monitor conformational changes associated with liquid-liquid phase separation. We find that FUS monomers undergo an unfolded-to-globular transition, whereas TDP-43 oligomerizes into partially disordered dimers and trimers. hCPEB3, on the other hand, remains fully disordered with a preference for fibrillar aggregation over LLPS. The divergent assembly mechanisms revealed by ion mobility mass spectrometry of soluble protein species that exist under LLPS conditions suggest structurally distinct complexes inside liquid droplets that may impact RNA processing and translation depending on biological context

Systemisches Denken im Fachunterricht

The ability to think in terms of time, in models, and to act in a systematic way is regarded as an important learning goal in most natural and sociological subjects. Particularly suitable for the promotion of systemic thinking are causal loop diagrams and system dynamics, which this book focuses on. The first contributions address the theoretical foundations of systems thinking, the design of causal loop diagrams, learning with system dynamics, the modeling tool Insight Maker, and generic structures or system archetypes, which are found in many different situations. The other articles show the importance of systems thinking and the design of learning environments in several several subjects: - Biology - German - Physics - Geography - History - Politics - EconomyDie Fähigkeit, sowohl vernetzt, in Zeitabläufen und in Modellen zu denken als auch systemgerecht zu handeln – kurz: systemisch zu denken – wird in den meisten natur- und gesellschaftswissenschaftlichen Fächern als wichtiges Lernziel angesehen. Besonders geeignet zur Förderung des systemischen Denkens sind Wirkungsdiagramme und System Dynamics, die im Zentrum des vorliegenden Buchs stehen. Die ersten Beiträge widmen sich den theoretischen Grundlagen des systemischen Denkens, der Gestaltung von Wirkungsdiagrammen, dem Lernen mit System Dynamics, dem Modelliertool Insight Maker und generischen Strukturen bzw. Systemarchetypen, die sich sich in vielen unterschiedlichen Situationen finden und somit ein hohes Transferpotenzial aufweisen. Die weiteren Artikel zeigen die Bedeutung des systemischen Denkens und die Unterrichtsgestaltung anhand exemplarischer Beispiele in mehreren Fächern auf: - Deutsch - Biologie - Physik - Geographie - Geschichte - Politik - Wirtschaft Auf der Website des Buchs (www.wirtschaft-lernen.de/systemisches_denken) finden sich Materialien wie Aufgabenblätter, Screencasts und die verwendeten Modelle

Structural Determinants of the Dictyostatin Chemotype for Tubulin Binding Affinity and Antitumor Activity Against Taxane- and Epothilone-Resistant Cancer Cells

13 p.-5 fig.-2 tab.-1 graph.abst.A combined biochemical, structural, and cell biology characterization of dictyostatin is described, which enables an improved understanding of the structural determinants responsible for the high-affinity binding of this anticancer agent to the taxane site in microtubules (MTs). The study reveals that this macrolide is highly optimized for MT binding and that only a few of the structural modifications featured in a library of synthetic analogues resulted in small gains in binding affinity. The high efficiency of the dictyostatin chemotype in overcoming various kinds of clinically relevant resistance mechanisms highlights its potential for therapeutic development for the treatment of drug-resistant tumors. A structural explanation is advanced to account for the synergy observed between dictyostatin and taxanes on the basis of their differential effects on the MT lattice. The X-ray crystal structure of a tubulin–dictyostatin complex and additional molecular modeling have allowed the rationalization of the structure–activity relationships for a set of synthetic dictyostatin analogues, including the highly active hybrid 12 with discodermolide. Altogether, the work reported here is anticipated to facilitate the improved design and synthesis of more efficacious dictyostatin analogues and hybrids with other MT-stabilizing agents.This work was supported in part by grants BIO2013-42984-R (J.F.D.) and SAF2012-39760-C02-02 (F.G.) from Ministerio de Economía y Competitividad, grant S2010/BMD-2457 BIPEDD2 from Comunidad Autónoma de Madrid (F.G. and J.F.D.), and the Swiss National Science Foundation grants 310030B_138659 and 31003A_166608 (M.O.S.). The authors acknowledge networking contribution by the COST Action CM1407 “Challenging organic syntheses inspired by nature—from natural products chemistry to drug discovery” and the COST action CM1470. I.P. thanks the EPSRC and AstraZeneca for funding, Dr. John Leonard (AstraZeneca) for useful discussions, Dr. Stuart Mickel (Novartis) for the provision of chemicals, and the EPSRC UK National Mass Spectrometry Facility at Swansea University for mass spectra