Light polarization under water near sunrise

Dramatic and rapid changes in the intensity and spectrum of light under water at dusk and dawn are well known, but reports regarding the light's polarization at these periods are sparse. Using a rapid spectropolarimeter, we examined the spatial and spectral characteristics of the underwater polarization patterns from sunrise to midday and compared them with a Rayleigh-based model for e-vector orientation and percent polarization. With the Sun near the horizon, the underwater polarization patterns were distinctive. Unlike the polarization at small solar zenith angles, the underwater polarization at large solar zenith angles cannot be predicted by simple Rayleigh scattering, most likely because of the relatively high contribution of skylight. At sunrise, the underwater polarization pattern outside of Snell's window differed from that found during the day in percent polarization, spatial distribution, and wavelength dependence. These unique polarization characteristics may provide a polarization-sensitive animal with a distinct cue for mediating dial vertical migration performed by plankton or with another timing signal.     

甲酸乙酯与二氧化碳混合熏蒸可食用鲜切花（中英文）

西花蓟马（缨翅目）是蓟马类中一种具有代表性的植物害虫,是一种能够对作物生产造成不利影响的多食性物种。因此,在欧盟,这些蓟马物种被作为检疫生物进行管理。西花蓟马以易感植物为食,并会传播几种导致严重植物疾病的病毒,从而对这些植物造成非常大的损害。以色列的供应占欧洲新鲜草本市场的50%,被认为是可食用鲜切花的主要供应市场。然而,在过去的十年中,由于没有可选的处理方法来控制检疫害虫而导致植物检疫失败,大大减少了出口量。目前尚无有效的采后杀虫处理方法。众所周知,熏蒸剂甲基溴（MB）具有植物毒性,尤其是对叶类产品和叶片,且与臭氧层的损耗有关。目前甲基溴仅能用作检疫和装运前熏蒸。甲酸乙酯（EF）被建议作为甲基溴的替代品,药效快、价格低廉、哺乳动物无毒性、环境无害、分解迅速,残留量极少或无残留。在以色列进行的30 g/m3甲酸乙酯与二氧化碳（1∶1.6）混合处理不同花种的实验中,在10和15 ℃条件下分别处理1和1.5 h,对西花蓟马各虫态均有较好的防治效果。在15 ℃暴露2 h,可杀死全部害虫,对花或其保质期没有不良影响。因此甲酸乙酯熏蒸可作为一种检疫处理方法,也是甲基溴（MB）的可行替代方法。     

Solid-State Electron Transport Through Carbon Dots Junctions: The Role of Boron and Phosphorus Doping

Carbon dots (CDs) are a new class of nanoparticles that gained widespread attention recently because of their easy preparation, water solubility, biocompatibility, and bright luminescence, leading to their integration in various applications. Despite their nm-scale and proven electron transfer capabilities, the solid-state electron transport (ETp) across single CDs was never explored. Here, a molecular junction configuration is used to explore the ETp across CDs as a function of their chemical structure using both DC-bias current–voltage and AC-bias impedance measurements. CDs are used with Nitrogen and Sulfur as exogenous atoms and doped with small amounts of Boron and Phosphorous. It is shown that the presence of P and B highly improves the ETp efficiency across the CDs, yet without an indication of a change in the dominant charge carrier. Instead, structural characterizations reveal significant changes in the chemical species across the CDs: the formation of sulfonates and graphitic Nitrogen. Temperature-dependent measurements and normalized differential conductance analysis reveal that the ETp mechanism across the CDs behaves as tunneling, which is common to all CDs used here. The study shows that the conductivity of CDs is on par with that of sophisticated molecular wires, suggesting CDs as new ‘green’ candidates for molecular electronics applications.     

Injectable Cardiac Cell Microdroplets for Tissue Regeneration

One of the strategies for heart regeneration includes cell delivery to the defected heart. However, most of the injected cells do not form quick cell–cell or cell–matrix interactions, therefore, their ability to engraft at the desired site and improve heart function is poor. Here, the use of a microfluidic system is reported for generating personalized hydrogel‐based cellular microdroplets for cardiac cell delivery. To evaluate the system's limitations, a mathematical model of oxygen diffusion and consumption within the droplet is developed. Following, the microfluidic system's parameters are optimized and cardiac cells from neonatal rats or induced pluripotent stem cells are encapsulated. The morphology and cardiac specific markers are assessed and cell function within the droplets is analyzed. Finally, the cellular droplets are injected to mouse gastrocnemius muscle to validate cell retention, survival, and maturation within the host tissue. These results demonstrate the potential of this approach to generate personalized cellular microtissues, which can be injected to distinct regions in the body for treating damaged tissues.     

Nutrition Alters the Stiffness of Adipose Tissue and Cell Signaling

Adipose tissue is a complex organ composed of various cell types and an extracellular matrix (ECM). The visceral adipose tissue (VAT) is dynamically altered in response to nutritional regimens that lead to local cues affecting the cells and ECM. The adipocytes are in conjunction with the surrounding ECM that maintains the tissue’s niche, provides a scaffold for cells and modulates their signaling. In this study, we provide a better understanding of the crosstalk between nutritional regimens and the ECM’s stiffness. Histological analyses showed that the adipocytes in mice fed a high-fat diet (HFD) were increased in size, while the ECM was also altered with changes in mass and composition. HFD-fed mice exhibited a decrease in elastin and an increase in collagenous proteins. Rheometer measurements revealed a stiffer ECM in whole tissue (nECM) and decellularized (deECM) in HFD-fed animals. These alterations in the ECM regulate cellular activity and influence their metabolic function. HFD-fed mice expressed high levels of the receptor for advanced-glycation-end-products (RAGE), indicating that AGEs might play a role in these processes. The cells also exhibited an increase in phosphoserine³³² of IRS-1, a decrease in the GLUT4 transporter levels at the cells’ membrane, and a consequent reduction in insulin sensitivity. These results show how alterations in the stiffness of ECM proteins can affect the mechanical cues transferred to adipocytes and, thereby, influence the adipocytes’ functionality, leading to metabolic disorders.     

Adjustable photoluminescence of peptide nanotubes coatings

Peptide nanotubes (PNTs) have become a significant subject at the biological and bionanotechnology field. Here we describe the spectroscopic analysis of PNTs coatings, which were deposited by a physical vapor deposition technology. We show that we can adjust the electronic, and consequently the spectroscopic, photoluminescence (PL) properties of the PNT coatings, simply by changing the parameters of the PNT deposition. We show that by controlling the PNT deposition parameters we can observe different PL properties of the PNT coatings and significantly strengthen the PL in the visible blue region. We further explain that the strong blue emission is resulting from the conversion of the monomers to a different chemical structure. The strong blue emission, and our ability to adjust it, promotes the use of the PNTs as organic materials for light emitting devices.     

The Role of Surface Groups in Dictating the Chiral-Solvent-Induced Assembly of Carbon Dots into Structures Exhibiting Circularly Polarized Luminescence

Here, the use of achiral nanoparticles and solvent-induced chirality transfer is combined for the making of large structures exhibiting chiroptical properties in the form of circularly polarized luminescence (CPL). The nanoparticles that the authors use are carbon dots (C-Dots) that are known for their bright luminescence and the ability to tune their surface moieties by using different precursors in their synthesis. Here, the result of adding the chiral solvent limonene into an aqueous solution of various C-Dots is explored, differentiated by their surface group. It is shown that only nitrogen-containing C-Dots with amine functional groups see the emergence of a CPL signal and the formation of a large fibrillar assembled structure. The various forces happening in the interface between the C-Dots and the limonene phase and the role of the amine groups in both the chirality transfer interactions and the interactions between C-Dots in the assembly process are discussed, whereas these two processes intertwine with each other. The ability to form fluorescent chiral structures exhibiting CPL from achiral nanoparticles and the understanding of the various interactions in this process are both important to the rationale design of any supramolecular chiral assemblies.     

AUTOMATICALLY IDENTIFYING CITATIONS IN HEBREW-ARAMAIC DOCUMENTS

Citations in documents contain important information about the sources that authors cite and their importance and impact. Therefore, automatic identification of citations from documents is an important task. Citations included in rabbinic literature are more difficult to identify and to extract than citations in scientific papers written in English for various reasons. The aim of this novel research is to automatically identify undated citations included a unique data set: rabbinic documents written in Hebrew-Aramaic. We formulate four feature sets: orthographic, quantitative, stopword-based, and n-gram-based. Different experiments on all combinations of these feature sets using six common machine learning methods and Infogain have been performed. A combination of all four feature sets using logistic regression achieves an accuracy of 91.98%, which is an improvement of 16.53% compared to a baseline result.