Transient inviscid flow in a passive linear model of the cochlea

Detailed knowledge of the fluid dynamics within the cochlea is important for a complete understanding of the physiology of this complex organ. We present a numerical simulation in the time domain for the inviscid two-dimensional flow in a passive cochlea. Numerical results are presented for a click stimulation and an impulsively started tone. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Low-Field NMR Study of Shortcake Biscuits with Cricket Powder,and Their Nutritional and Physical Characteristics

The growing human population renders challenges for the future supply of food products with high nutritional value. Here, we enhanced the functional and nutritional value of biscuits, a popular sweet snack, by replacing the wheat flour with 2%, 6%, or 10% (w/w) cricket powder. Consumer acceptance ratings for reference and 2% augmented cookies were comparable, whereas the higher levels of enhancement received inferior consumer scores. This relatively small change in biscuit recipe provided significant and nutritionally desirable enhancements in the biscuits, observed in a series of analyses. An increase in the protein content was observed, including essential amino acids, as well as minerals and fat. This conversion also affected the physical properties of the biscuits, including hardness, and water molecular dynamics measured by ¹H NMR. Cricket powder-augmented biscuits join the line of enhanced, functionally superior food products. This and similar food augmentation provide a viable scenario to meet the human food demands in the future.     

Selective Esterification of Phosphonic Acids

Here, we report straightforward and selective synthetic procedures for mono- and diesterification of phosphonic acids. A series of alkoxy group donors were studied and triethyl orthoacetate was found to be the best reagent as well as a solvent for the performed transformations. An important temperature effect on the reaction course was discovered. Depending on the reaction temperature, mono- or diethyl esters of phosphonic acid were obtained exclusively with decent yields. The substrate scope of the proposed methodology was verified on aromatic as well as aliphatic phosphonic acids. The designed method can be successfully applied for small- and large-scale experiments without significant loss of selectivity or reaction yield. Several devoted experiments were performed to give insight into the reaction mechanism. At 30 °C, monoesters are formed via an intermediate (1,1-diethoxyethyl ester of phosphonic acid). At higher temperatures, similar intermediate forms give diesters or stable and detectable pyrophosphonates which were also consumed to give diesters. ³¹P NMR spectroscopy was used to assign the structure of pyrophosphonate as well as to monitor the reaction course. No need for additional reagents and good accessibility and straightforward purification are the important aspects of the developed protocols.     

Polarons in magnesium-doped lithium niobate crystals induced by femtosecond light pulses

Strong light-induced absorption has been observed in lithium niobate crystals doped with magnesium after application of femtosecond illumination. In this material there are no Nb-on-Li-site defects and hence no antisite polarons occur, but small free polarons close to the conduction band can be generated. The light-induced absorption observed is attributed to these polarons. For LiNbO₃:Mg, their decay times are about two orders of magnitude smaller than those of the Nb-on-Li-site polarons in undoped material. The results are relevant for a better understanding of the suppression of the so-called optical damage in these crystals and for their use in femtosecond applications.     

Synthesis of Indomorphan Pseudo‐Natural Product Inhibitors of Glucose Transporters GLUT‐1 and ‐3

Bioactive compound design based on natural product (NP) structure may be limited because of partial coverage of NP‐like chemical space and biological target space. These limitations can be overcome by combining NP‐centered strategies with fragment‐based compound design through combination of NP‐derived fragments to afford structurally unprecedented “pseudo‐natural products” (pseudo‐NPs). The design, synthesis, and biological evaluation of a collection of indomorphan pseudo‐NPs that combine biosynthetically unrelated indole‐ and morphan‐alkaloid fragments are described. Indomorphane derivative Glupin was identified as a potent inhibitor of glucose uptake by selectively targeting and upregulating glucose transporters GLUT‐1 and GLUT‐3. Glupin suppresses glycolysis, reduces the levels of glucose‐derived metabolites, and attenuates the growth of various cancer cell lines. Our findings underscore the importance of dual GLUT‐1 and GLUT‐3 inhibition to efficiently suppress tumor cell growth and the cellular rescue mechanism, which counteracts glucose scarcity.     

Molecularly imprinted polymer film grafted from porous silica for efficient enrichment of steroid hormones in water samples

Steroid hormones as endocrine disrupting compounds can interfere with the functioning of hormonal systems of organisms and thus affect the health and reproduction of humans and wildlife. Unfortunately, these types of harmful endocrine disrupting compounds have been found in a variety of environmental samples at very low concentrations. Therefore, a simple, fast, and efficient method for enrichment of water samples is needed. A molecularly imprinted solid‐phase extraction combined with high performance liquid chromatography coupled with diode array detection was developed for the determination of six steroid hormones, such as estrone, 17‐β‐estradiol, estriol, 17‐α‐ethinylestradiol, progesterone, and testosterone in water samples. The recoveries obtained in the proposed method were in the range of 78.7–101.3%. Matrix effect below 20% suggests that the quantitative and qualitative results of the analysis were not significantly affected by the matrix. The results show that molecularly imprinted polymers based on spherical silica gel had the potential to be a highly innovative and selective sorbent. The proposed method was proved to be applicable for molecularly imprinted solid‐phase extraction in selective and reliable extraction and enrichment of steroid hormones in environmental water samples.     

Computation of Acoustic Far-Fields with the Spectral Lighthill Method

Based on Lighthill's acoustic analogy we formulate the Spectral Lighthill Method (SLM). SLM is a method for the computation of acoustic far-fields. It uses a spatio-temporal Fourier transform of the Lighthill stress tensor. We show that SLM is a straightforward tool for the computation of acoustic far-fields that enhances our physical understanding of sound generation and is useful in the numerical analysis of acoustic far-field solvers. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Using physics-informed enhanced super-resolution generative adversarial networks for subfilter modeling in turbulent reactive flows

Turbulence is still one of the main challenges in accurate prediction of reactive flows. Therefore, the development of new turbulence closures that can be applied to combustion problems is essential. Over the last few years, data-driven modeling has become popular in many fields as large, often extensively labeled datasets are now available and training of large neural networks has become possible on graphics processing units (GPUs) that speed up the learning process tremendously. However, the successful application of deep neural networks in fluid dynamics, such as in subfilter modeling in the context of large-eddy simulations (LESs), is still challenging. Reasons for this are the large number of degrees of freedom in natural flows, high requirements of accuracy and error robustness, and open questions, for example, regarding the generalization capability of trained neural networks in such high-dimensional, physics-constrained scenarios. This work presents a novel subfilter modeling approach based on a generative adversarial network (GAN), which is trained with unsupervised deep learning (DL) using adversarial and physics-informed losses. A two-step training method is employed to improve the generalization capability, especially extrapolation, of the network. The novel approach gives good results in a priori and a posteriori tests with decaying turbulence including turbulent mixing, and the importance of the physics-informed continuity loss term is demonstrated. The applicability of the network in complex combustion scenarios is furthermore discussed by employing it in reactive and inert LESs of the Spray A case defined by the Engine Combustion Network (ECN).     

Absolute Quantification of Noncoding RNA by Microscale Thermophoresis

Accurate quantification of the copy numbers of noncoding RNA has recently emerged as an urgent problem, with impact on fields such as RNA modification research, tissue differentiation, and others. Herein, we present a hybridization‐based approach that uses microscale thermophoresis (MST) as a very fast and highly precise readout to quantify, for example, single tRNA species with a turnaround time of about one hour. We developed MST to quantify the effect of tRNA toxins and of heat stress and RNA modification on single tRNA species. A comparative analysis also revealed significant differences to RNA‐Seq‐based quantification approaches, strongly suggesting a bias due to tRNA modifications in the latter. Further applications include the quantification of rRNA as well as of polyA levels in cellular RNA.