Ring opening polymerization of lactides and lactones by multimetallic alkyl zinc complexes derived from the acids Ph₂C(X)CO₂2H (X = OH, NH₂ )

The reaction of the dialkylzinc reagents R₂Zn with the acids 2,2-Ph₂C(X)(CO₂H), where X = NH₂, OH, i.e. 2,2′-diphenylglycine (dpgH) or benzilic acid (benzH2), in toluene at reflux temperature afforded the tetra-nuclear ring complexes [RZn(dpg)]₄, where R = Me (1), Et (2), 2-CF₃C₆H₄ (3), and 2,4,6-F₃C₆H₂ (4); complex 2 has been previously reported. The crystal structures of 1·(2MeCN), 3 and 4·(4(C₇H₈)·1.59(H₂O)) are reported, along with that of the intermediate compound (2-CF₃C₆H₄)3B·MeCN and the known compound [ZnCl₂(NCMe)₂]. Complexes 1–4, together with the known complex [(ZnEt)₃(ZnL)₃(benz)₃] (5; L = MeCN), have been screened, in the absence of benzyl alcohol, for their potential to act as catalysts for the ring opening polymerization (ROP) of ε-caprolactone (ε-CL), δ-valerolactone (δ-VL) and rac-lactide (rac-LA); the co-polymerization of ε-CL with rac-LA was also studied. Complexes 3 and 4 bearing fluorinated aryls at zinc were found to afford the highest activities

ERRORS IN COMPUTERIZED OFFICE WORK : DIFFERENCES BETWEEN NOVICE AND EXPERT USERS *

Abstract: This paper deals with errors by novices an d experts when interacting with the computer i n normal office work . Three criteria ar e discussed to determine the level of expertise : a ) total length of time that the user has worke d computers, b) number of programs known, an d c) length of daily work-time with the computer . In contrast to widespread assumptions, expert s did not make less errors than novices (excep t knowledge errors) . On the other hand, expert s spent less time handling the errors tha n novices . A cluster analysis produced groups o f Occasional-, Frequent-, Beginning-an d General Users in the work force

Terretonin N: A New Meroterpenoid from Nocardiopsis sp.

Hamed A, Abdel-Razek AS, Frese M, et al. Terretonin N: A New Meroterpenoid from Nocardiopsis sp. Molecules. 2018;23(2): 299.Terretonin N (1), a new highly oxygenated and unique tetracyclic 6-hydroxymeroterpenoid, was isolated together with seven known compounds from the ethyl acetate extract of a solid-state fermented culture of Nocardiopsis sp. Their structures were elucidated by spectroscopic analysis. The structure and absolute configuration of 1 were unambiguously determined by X-ray crystallography. The isolation and taxonomic characterization of Nocardiopsis sp. is reported. The antimicrobial activity and cytotoxicity of the strain extract and compound 1 were studied using different microorganisms and a cervix carcinoma cell line, respectively

Twenty-four Hour Holter Monitoring in Finishing Cattle Housed Outdoors

Ambulatory electrocardiogram monitoring, in the form of Holter monitoring, has been used in human and veterinary medicine for decades as an aid in the diagnosis and determination of appropriate therapy of heart rhythm disturbances. Within veterinary medicine, Holter monitors have been primarily used in companion animal species, yet little attention has been given to food animal species. Moreover, the heart rhythm in clinically normal cattle fed high concentrate diets and housed outdoors in confined drylot facilities has not been previously reported. In order to properly identify pathologic arrhythmias in cattle, the normal rhythm and arrhythmia prevalence in healthy cattle should be defined. Most prior reports of arrhythmia in cattle have been recordings of relatively shorter duration and in animals that were hospitalized or being handled for various reasons. Therefore, the objective of this study was to determine normal Holter monitor registrations including heart rate, rhythm, number of ventricular premature complexes, and atrial premature complexes in unrestrained finishing Angus steers

Computertomographische Untersuchungen und Druckversuche an Robinienrundholz (KIT Scientific Reports ; 7610)

Robinienholz eignet sich wegen seiner hohen Festigkeit und ausgezeichneten Dauerhaftigkeit für tragende frei bewitterte Bauteile. Die natürliche Stammform mit ihren teilweise zahlreichen Krümmungen erschwert jedoch die Abschätzung der Tragfähigkeit. In dieser Arbeit wird auf der Grundlage der Ergebnisse von computertomographischen Untersuchungen und von Druckversuchen an natürlich gewachsenen Robinienstammabschnitten ein Modell zur Berechnung der Tragfähigkeit entwickelt

Deterministic Preparation of a Tunable Few-Fermion System

Systems consisting of few interacting fermions are the building blocks of matter with atoms and nuclei being the most prominent examples. We have created an artificial few-body quantum system with complete control over the system's quantum state using ultracold fermionic atoms in an optical dipole trap. We deterministically prepare ground state systems consisting of one to ten particles with fidelities of ~ 90%. We can tune the inter-particle interactions to arbitrary values using a Feshbach resonance and have observed the interaction-induced energy shift for a pair of repulsively interacting atoms. With this work, quantum simulation of strongly correlated fewbody systems has become possible. In addition, these microscopic quantum systems can be used as building blocks for scalable quantum information processing.Comment: 8 pages, 6 figure

A blood based 12-miRNA signature of Alzheimer disease patients

Background: Alzheimer disease (AD) is the most common form of dementia but the identification of reliable, early and non-invasive biomarkers remains a major challenge. We present a novel miRNA-based signature for detecting AD from blood samples. Results: We apply next-generation sequencing to miRNAs from blood samples of 48 AD patients and 22 unaffected controls, yielding a total of 140 unique mature miRNAs with significantly changed expression levels. Of these, 82 have higher and 58 have lower abundance in AD patient samples. We selected a panel of 12 miRNAs for an RT-qPCR analysis on a larger cohort of 202 samples, comprising not only AD patients and healthy controls but also patients with other CNS illnesses. These included mild cognitive impairment, which is assumed to represent a transitional period before the development of AD, as well as multiple sclerosis, Parkinson disease, major depression, bipolar disorder and schizophrenia. miRNA target enrichment analysis of the selected 12 miRNAs indicates an involvement of miRNAs in nervous system development, neuron projection, neuron projection development and neuron projection morphogenesis. Using this 12-miRNA signature, we differentiate between AD and controls with an accuracy of 93%, a specificity of 95% and a sensitivity of 92%. The differentiation of AD from other neurological diseases is possible with accuracies between 74% and 78%. The differentiation of the other CNS disorders from controls yields even higher accuracies. Conclusions: The data indicate that deregulated miRNAs in blood might be used as biomarkers in the diagnosis of AD or other neurological diseases

Recent magnetic views of the Antarctic lithosphere

Magnetic anomaly investigations are a key tool to help unveil subglacial geology, crustal architecture and the tectonic and geodynamic evolution of the Antarctic continent. Here, we present the second generation Antarctic magnetic anomaly compilation ADMAP 2.0 (Golynsky et al., 2018), that now includes a staggering 3.5 million line-km of aeromagnetic and marine magnetic data, more than double the amount of data available in the first generation effort. All the magnetic data were corrected for the International Geomagnetic Reference Field, diurnal effects, high-frequency errors and leveled, gridded,and stitched together. The new magnetic anomaly dataset provides tantalising new views into the structure and evolution of the Antarctic Peninsula and the West Antarctic Rift System within West Antarctica, and Dronning Maud Land, the Gamburtsev Subglacial Mountains, the Prince Charles Mountains, Princess Elizabeth Land, and Wilkes Land in East Antarctica, as well as key insights into oceanic gateways. Our magnetic anomaly compilation is helping unify disparate regional geologic and geophysical studies by providing larger-scale perspectives into the major tectonic and magmatic processes that affected Antarctica from Precambrian to Cenozoic times, including e.g. the processes of subduction and magmatic arc development, orogenesis, accretion, cratonisation and continental rifting, as well as continental margin and oceanic basin evolution. The international Antarctic geomagnetic community remains very active in the wake of ADMAP 2.0, and we will showcase some of their key ongoing study areas, such as the South Pole and Recovery frontiers, the Ross Ice Shelf, Dronning Maud Land and Princess Elizabeth Land