Structural Transition from Helices to Hemihelices

Helices are amongst the most common structures in nature and in some cases, such as tethered plant tendrils, a more complex but related shape, the hemihelix forms. In its simplest form it consists of two helices of opposite chirality joined by a perversion. A recent, simple experiment using elastomer strips reveals that hemihelices with multiple reversals of chirality can also occur, a richness not anticipated by existing analyses. Here, we show through analysis and experiments that the transition from a helical to a hemihelical shape, as well as the number of perversions, depends on the height to width ratio of the strip's cross-section. Our findings provides the basis for the deterministic manufacture of a variety of complex three-dimensional shapes from flat strips

The Sniffin’ Sticks Odor Discrimination Memory Test: A Rapid, Easy-to-Use, Reusable Procedure for Testing Olfactory Memory

Objectives: Neurodegenerative diseases can alter odor memory in addition to inducing quantitative impairment, and olfactory memory can be tested using the validated olfactory memory test with encapsulated odors (Odor Discrimination Memory Test [ODMT]). The aim of this study was to investigate the new Sniffin’ Sticks ODMT (SSODMT), which is comparable with the ODMT. Methods: The SSODMT was administered to 48 subjects (30 women, 18 men; mean age, 34.6 ± 16.3 years). Olfactory function was assessed using the 16-item Sniffin’ Sticks Identification Test. The ODMT was administered to a subgroup of 10 subjects to assess the comparability of the SSODMT and the ODMT. Test-retest reliability was studied in another 20 subjects (10 women, 10 men; mean age, 32.9 ± 16.4 years). Results: The mean SSODMT score was 10.7 ± 1.8 (range, 5-12). SSODMT test scores were significantly correlated with Sniffin’ Sticks Identification Test scores (r67 = 0.66, P < .001) and were significantly negatively correlated with subject age (r48 = −0.70, P < .001). SSODMT and ODMT scores were highly and significantly correlated, indicating that the test results were comparable (r10 = 0.75, P < .05). Test-retest analysis revealed a significant correlation (r20 = 0.68, P < .001). Conclusions: These results demonstrate the usefulness of the new SSODMT and its comparability with the ODMT. The SSODMT is an easy, rapid, and low-cost tool that is suitable for routine use in evaluating odor memory

The large area detector onboard the eXTP mission

The Large Area Detector (LAD) is the high-throughput, spectral-timing instrument onboard the eXTP mission, a flagship mission of the Chinese Academy of Sciences and the China National Space Administration, with a large European participation coordinated by Italy and Spain. The eXTP mission is currently performing its phase B study, with a target launch at the end-2027. The eXTP scientific payload includes four instruments (SFA, PFA, LAD and WFM) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. The LAD instrument is based on the design originally proposed for the LOFT mission. It envisages a deployed 3.2 m2 effective area in the 2-30 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors - offering a spectral resolution of up to 200 eV FWHM at 6 keV - and of capillary plate collimators - limiting the field of view to about 1 degree. In this paper we will provide an overview of the LAD instrument design, its current status of development and anticipated performance

Effects of localized application of porous material on trailing-edge noise of a circulation-controlled wing

Deutsche ForschungsgemeinschaftPeerReviewe

Growth rate as a function of the mode number for three different strips characterized by , , and .

<p>The growth rate is determined when the applied force decreases to .</p

Snapshots recorded from the finite element simulations, illustrating the formation of (A) a helix, (B) a hemihelix with single perversion and (C) a hemihelix with 12 perversions.

<p>The colors represent the local values of the computed von Mises stress. The prestrain was the same in all three cases. , , (A) , (B) , (C) . The images are taken when the end to end distances are . Gravity was included in the simulations and acts from left to right in these images.</p

Contour plots showing the value of for which the growth rate is maximum as function to and .

<p>The growth rates are calculated for . Black dotted lines show the boundaries between modes with different number of perversions , while the red line corresponds to and separates hemihelices (on its left) from helices (on its right). For clarity not all the higher modes are shown.</p