Photographische Untersuchung des Aufschlags sehr schneller Geschosse auf Nylon-Gewebe. II. Bremsung des Geschosses und kritische Transversalgeschwindigkeit

Ohne Zusammenfassung     

Use of a capacitance measurement device for surrogate noncontact conductance measurement

A capacitance to digital converter (AD7746) is used in the same mode as noncontact conductance detectors. The detector output is linearly proportional to specific conductance (sigma) at low sigma values but becomes nonlinear and reaches a plateau value at sigma approximately >0.75 mS/cm, regardless of the nature of the electrolyte. For all applications at sub- to low-mM concentrations, the device, available as an evaluation board, provides a very affordable nothing-else-required means of contactless surrogate conductivity detection from capillary scale to larger bore conduits. For the same measurement cell volume, the detector provides virtually the same limits of detection (LODs) as a standard galvanic contact conductivity detector in conventional scale suppressed conductometric ion chromatography. The detection limits deteriorate as the conduit inner diameter decreases.     

Short,Enantioselective Total Synthesis of Highly Oxidized Taxanes

In the realm of natural product chemistry, few isolates have risen to the level of fame justifiably accorded to Taxol ( 1 ) and its chemical siblings. This report describes the most concise route to date for accessing the highly oxidized members of this family. As representative members of taxanes containing five oxygen atoms, decinnamoyltaxinine E ( 2 ) and taxabaccatin III ( 3 ), have succumbed to enantioselective total synthesis for the first time in only 18 steps from a simple olefin starting material. The strategy holistically mimics nature's approach (two‐phase synthesis) and features a carefully choreographed sequence of stereoselective oxidations and a remarkable redox‐isomerization to set the key trans‐diol present in 2 and 3 . This work lays the critical groundwork necessary to access even higher oxidized taxanes such as 1 in a more practical fashion, thus empowering a medicinal chemistry campaign that is not wedded to semi‐synthesis.     

Structure modification in hen egg yolk low density lipoproteins layers between 30 and 45 mN/m observed by AFM

We have studied the structure of films made by low density lipoproteins (LDL) from hen egg yolk, which are composed of apoproteins, neutral lipids and phospholipids. These LDL have been deposited on air–water interface to form a monolayer which has been compressed to measure an isotherm using Langmuir balance. This isotherm presented three transitions (neutral lipid (surface pressure, π = 19 mN/m), apoprotein–lipid (π = 41 mN/m) and phospholipid (π = 51 mN/m) transitions). We have studied only the apoprotein–lipid transition. In order to observe the LDL film structure before (π = 30 mN/m) and after (π = 45 mN/m) the apoprotein–lipid transition, the formed films were transferred and visualised by atomic force microscopy (AFM). Our results have shown that the structures observed in the LDL film were different depending on the surface pressure. The apoproteins and neutral lipids appeared to be miscible up to the apoprotein–lipid transition, when demixing occured. The structures observed after the apoprotein–lipid transition should be due to the demixing between apoproteins and neutral lipids. On the other hand, apoproteins and phospholipids seemed miscible whatever the surface pressure. Hence, the first transition (π = 19 mN/m) should be attributed to the free neutral lipid collapse; the second transition (π = 41 mN/m) should be attributed to the demixing of apoprotein–neutral lipid complexes; and the last transition (π = 51 mN/m) should be attributed to phospholipid collapse or to demixing of apoprotein–phospholipid complexes.     

Addressing the Clumsiness Loophole in a Leggett-Garg Test of Macrorealism

The rise of quantum information theory has lent new relevance to experimental tests for non-classicality, particularly in controversial cases such as adiabatic quantum computing superconducting circuits. The Leggett-Garg inequality is a “Bell inequality in time” designed to indicate whether a single quantum system behaves in a macrorealistic fashion. Unfortunately, a violation of the inequality can only show that the system is either (i) non-macrorealistic or (ii) macrorealistic but subjected to a measurement technique that happens to disturb the system. The “clumsiness” loophole (ii) provides reliable refuge for the stubborn macrorealist, who can invoke it to brand recent experimental and theoretical work on the Leggett-Garg test inconclusive. Here, we present a revised Leggett-Garg protocol that permits one to conclude that a system is either (i) non-macrorealistic or (ii) macrorealistic but with the property that two seemingly non-invasive measurements can somehow collude and strongly disturb the system. By providing an explicit check of the invasiveness of the measurements, the protocol replaces the clumsiness loophole with a significantly smaller “collusion” loophole.