פרסומים

Neural crest cells (NCCs) are a transient population of neuroectodermal-originated cells that populate the dorsal neural tube (dNT), before migrating and giving rise to multiple cell lineages in the developing embryo. Prior to their migration, NCCs undergo epithelial-to-mesenchymal-transition (EMT) through which they lose cell contacts and detach from the dNT to invade their surrounding environment. Multiple signals and transcription factors have been identified to regulate these events. Yet, less is known regarding effectors that act downstream to execute the actual NCC separation and migration. Matrix metalloproteinases (MMPs) are a family of proteases that degrade the extracellular matrix as well as other pericellular proteins during processes of tissue remodeling, angiogenesis and metastasis. Previously, we and others have demonstrated the role of the gelatinases MMP2 and MMP9 during the onset of NCC migration. Several evidences link the cleavage and activation of these secreted gelatinases to the activity of membrane-type MMPs (MT-MMP), such as MMP14 and MMP16, which are tethered to plasma membrane and affect various cellular behaviors. The aim of this study was to investigate whether MMP16 acts in NCCs. Here we demonstrate the expression of MMP16 mRNA and protein in cranial NCCs in avian embryos. Knockdown of MMP16 inhibited NCC migration. This inhibition was rescued by the addition of recombinant MMP16, which was also sufficient to increase proper NCC migration. Furthermore, excess MMP16 caused enhanced NCC EMT, concomitant with degradation of dNT-related proteins, laminin and N-cadherin. Altogether, these results uncover MMP16 as a new effector participating in EMT and in the migration of NCCs.

Neural crest cells (NCCs) are a transient population of neuroectodermal-originated cells that populate the dorsal neural tube (dNT), before migrating and giving rise to multiple cell lineages in the developing embryo. Prior to their migration, NCCs undergo epithelial-to-mesen-chymal-transition (EMT) through which they lose cell contacts and detach from the dNT to invade their surrounding environment. Multiple signals and transcription factors have been identified to regulate these events. Yet, less is known regarding effectors that act downstream to execute the actual NCC separation and migration. Matrix metalloproteinases (MMPs) are a family of proteases that degrade the extracellular matrix as well as other pericellular proteins during processes of tissue remodeling, angiogenesis and metastasis. Previously, we and others have demonstrated the role of the gelatinases MMP2 and MMP9 during the onset of NCC migration. Several evidences link the cleavage and activation of these secreted gelatinases to the activity of membrane-type MMPs (MT-MMP), such as MMP14 and MMP16, which are tethered to plasma membrane and affect various cellular behaviors. The aim of this study was to investigate whether MMP16 acts in NCCs. Here we demonstrate the expression of MMP16 mRNA and protein in cranial NCCs in avian embryos. Knockdown of MMP16 inhibited NCC migration. This inhibition was rescued by the addition of recombinant MMP16, which was also sufficient to increase proper NCC migration. Furthermore, excess MMP16 caused enhanced NCC EMT, concomitant with degradation of dNT-related proteins, laminin and N-cadherin. Altogether, these results uncover MMP16 as a new effector participating in EMT and in the migration of NCCs.

BACKGROUND: Standardization of the dietetic care process allows for early identification of malnutrition and metabolic disorders, interdisciplinary collaboration among the medical team, and improved quality of patient care. Globally, dietitians are adopting a nutrition care model that integrates national regulations with professional scope of practice. Currently, Israel lacks a standardized dietetic care process and documentation terminology. OBJECTIVES: To assess the utilization of a novel sectoral documentation system for nutrition care in Israel. METHODS: Seventy dietitians working in 63 geriatric facilities completed an online training program presenting the proposed patient-sectoral-model. Training was followed by submission of sample case studies from clinical practice or completion of a case simulation. Application of the proposed model was assessed by measuring the frequency participants implemented different sections of the model and responses to an approval questionnaire. RESULTS: Fifty-four participants (77%) provided completed cases. Over 80% of participants reported each step of the proposed dietary care process with 100% reporting the "nutrition diagnosis". Fifty-one dietitians (72.8%) completed the approval survey with the section on nutrition diagnosis receiving a highly favorable response (95%), indicating that the new documentation system was beneficial. Over 80% of participants rated the model useful in clinical practice. CONCLUSIONS: A sectoral approach for documenting dietetic care may be the ideal model for dietitians working in specific patient populations with the potential for improving interdisciplinary collaboration in patient care.

This study explores the latest changes in Western European immigration to the United States by integrating several large databases: the U.S. census, the American Community Surveys, the European Social Survey, as well as the Human Development Index and Gini index. Findings show that the number of individuals born in Western Europe but with family origins elsewhere who have been immigrating to and settling in the United States is increasing. I divide the Western European population that immigrates to the United States into seven different subpopulations by their ancestries and explore the characteristics of these populations before and after immigrating to the United States. I also examine their relative success in terms of economic and labor outcomes in America, finding, for example, that some of the least advantaged immigrant groups have some of the best economic outcomes in the United States. The different self-selection and assimilation patterns among these immigrants have implications for U.S. public policy, which we identify and begin to explore.

The observation and manipulation of electron dynamics in matter call for attosecond light pulses, routinely available from high-order harmonic generation driven by few-femtosecond lasers. However, the energy limitation of these lasers supports only weak sources and correspondingly linear attosecond studies. Here we report on an optical parametric synthesizer designed for nonlinear attosecond optics and relativistic laser-plasma physics. This synthesizer uniquely combines ultra-relativistic focused intensities of about 1020 W/cm2 with a pulse duration of sub-two carrier-wave cycles. The coherent combination of two sequentially amplified and complementary spectral ranges yields sub-5-fs pulses with multi-TW peak power. The application of this source allows the generation of a broad spectral continuum at 100-eV photon energy in gases as well as high-order harmonics in relativistic plasmas. Unprecedented spatio-temporal confinement of light now permits the investigation of electric-field-driven electron phenomena in the relativistic regime and ultimately the rise of next-generation intense isolated attosecond sources.

Being a major conception of chemistry, Lewis acids have found countless applications throughout chemical enterprise. Although many chemical elements can serve as the central atom of Lewis acids, nitrogen is usually associated with Lewis bases. Here, we report on the first example of robust and modifiable Lewis acids centered on the nitrogen atom, which provide stable and well-characterized adducts with various Lewis bases. On the basis of the reactivity of nitrogen Lewis acids, we prepared, for the first time, cyclic triazanes, a class of cyclic organic compounds sequentially bearing three all-saturated nitrogen atoms (N–N–N motif). Reactivity abilities of these N-Lewis acids were explained by theoretical calculations. Properties and future applications of nitrogen Lewis acids are intriguing.

The nitrogen-vacancy (NV) center in diamond has shown great promise of nanoscale sensing applications, however, near-surface NV suffer from relatively short spin coherence time that limits its sensitivity. This is presumably caused by improper surface termination. Using first-principles calculations, we propose that nitrogen-terminated (111) diamond provides electrical inactivity and surface spin noise free properties. We anticipate that the nitrogen-terminated (111) surface can be fabricated by nitrogen plasma treatment. Our findings pave the way toward an improved NV-based quantum sensing and quantum simulation operating at room temperature.

Question: What are the controls on biomass production and species diversity in Mediterranean grasslands? Do medium-term (i.e. inter-annual) precipitation legacy effects on biomass production and diversity occur in these grasslands?. Location: Karei Deshe Experimental Range Station, Upper Galilee, northern Israel. Methods: We used a long-term (21-r) cattle-grazing experiment in a Mediterranean grassland to search for evidence of precipitation legacies on herbaceous above-ground biomass production and species diversity. Biomass production was measured in two seasonal late grazing treatments, in the winter and at peak vegetative production in the spring, while species diversity was determined at peak production. We used ANCOVA to test the effects of residual biomass, previous year's stocking density and previous year's biomass on current biomass production. We ran forward selection and ANCOVA to test for precipitation legacies, using precipitation variables relating to both previous and current year's rainfall. In addition we examined linear regressions of biomass and species diversity on current year's precipitation. Results: Biomass production and species diversity showed weak to negligible relationships with current year's precipitation. Biomass production, and to a lesser extent, diversity, were affected by inter-annual fluctuations in growing conditions. However, evidence of inter-annual precipitation legacies were found only for early season biomass production, and not for peak biomass production or species diversity. We found no effect of grazing on biomass production at the onset of the grazing season, regardless of important differences in previous year's stocking density. Additionally, we found no effect of previous year's biomass production or stocking density on the following year's biomass or diversity, but peak biomass production was strongly related to previous year's residual biomass. Conclusions: The lack of an inter-annual precipitation legacy on peak biomass production contributes to a growing body of evidence showing that Mediterranean ecosystems are unique among semi-arid and sub-humid ecosystems, where precipitation legacies play an integral role. Mediterranean ecosystems are unique in their combined long-term high variability in rainfall and long grazing history. This lack of precipitation legacy led to the development of vegetation that is highly resistant to inter-annual fluctuations in growing conditions. We propose that the high resistance contributes to the lack of inter-annual, or medium-term, precipitation legacies on the studied grassland, and may contribute to its persistence under future projected climate change in the region. © 2016 International Association for Vegetation Science

Nonalcoholic fatty liver diseases (NAFLD) is one of the most common chronic liver disease in Western countries. Oxygen is a central component of the cellular microenvironment, which participate in the regulation of cell survival, differentiation, functions and energy metabolism. Accordingly, sufficient oxygen supply is an important factor for tissue durability, mainly in highly metabolic tissues, such as the liver. Accumulating evidence from the past few decades provides strong support for the existence of interruptions in oxygen availability in fatty livers. This outcome may be the consequence of both, impaired systemic microcirculation and cellular membrane modifications which occur under steatotic conditions. This review summarizes current knowledge regarding the main factors which can affect oxygen supply in fatty liver.

PURPOSE: Data on non-fermentative Gram-negative rods (NFGNR) bacteremia in children with malignancies are limited. The aim of this study was to present clinical picture, antimicrobial susceptibility pattern, risk factors for resistance and outcome in NFGNR bacteremia in children with cancer. METHODS: All episodes of NFGNR bacteremia occurring during 2001-2014 in children with cancer in a tertiary-care hospital were retrospectively analyzed. Pseudomonas and Acinetobacter spp. resistant to three or more antibiotic classes and all Stenotrophomonas maltophilia (SM) were defined as multidrug-resistant bacteria (MDR). RESULTS: A total of 80 children (44 males, 0.8-18 years, median 5 years) developed 107 episodes (116 pathogens) of NFGNR bacteremia; Pseudomonas aeruginosa (PA) (51; 43.9%), Acinetobacter baumannii (AB) (21, 18.1%), SM (18, 15.5%); and others (27, 25.2%). The rate of NFGNR bacteremia in children with certain solid tumors (e.g. sarcoma, 12/134 (9.0%)) was comparable to that of hematological malignancies (52/429 (12.2%). Focal infection and septic shock occurred in 16 (14.9%) and four (3.7%) episodes, respectively. Thirty (25.8%) of 116 NFGNR were MDR. The most significant predictors of bacteremia with MDR PA or AB were severe neutropenia (<100 cells/mm(3); OR 7.8, p = 0.002), hospital-acquired (OR 16.9, p < 0.0001) and breakthrough (OR 11.2, p < 0.0001) infection. Infection with MDR bacteria was associated with inappropriate empirical therapy. The 30-day mortality was 3/107 (2.8%), all in neutropenic patients with hematological malignancies. CONCLUSIONS: NFGNR bacteremia can present with nonspecific signs or symptoms. MDR NFGNRs are common and compromise treatment options, but mortality is relatively low. Knowledge of local epidemiology, pattern and risk factors for resistance is important to guide empirical therapy.

We observe nonmonotonic aging and memory effects, two hallmarks of glassy dynamics, in two disordered mechanical systems: crumpled thin sheets and elastic foams. Under fixed compression, both systems exhibit monotonic nonexponential relaxation. However, when after a certain waiting time the compression is partially reduced, both systems exhibit a nonmonotonic response: the normal force first increases over many minutes or even hours until reaching a peak value, and only then is relaxation resumed. The peak time scales linearly with the waiting time, indicating that these systems retain long-lasting memory of previous conditions. Our results and the measured scaling relations are in good agreement with a theoretical model recently used to describe observations of monotonic aging in several glassy systems, suggesting that the nonmonotonic behavior may be generic and that athermal systems can show genuine glassy behavior.

Summary Abiotic stresses have severe detrimental effects on agricultural productivity worldwide. Abscisic acid (ABA) levels rise in response to abiotic stresses, and play a role in coordinating physiological responses. ABA elicits its effects by binding a family of soluble receptors, increasing affinity of the receptors to type 2C phosphatases (PP2Cs) leading to phosphatase inhibition. In the current study, we conducted a comprehensive analysis of the ABA signaling pathway in the cereal model grass Brachypodium distachyon. The Brachypodium genome encodes a family of 10 functionally conserved ABA receptors. The 10th in the series, BdPYL10, encodes a defective receptor and is likely a pseudogene. Combinatorial protein interaction assay further validated computational analysis, which grouped Brachypodium ABA receptors into three subfamilies, similarly to Arabidopsis classification. Brachypodium subfamily III receptors inhibited PP2C activity in vitro and complemented Arabidopsis quadruple (pyr1/pyl1/pyl2/pyl4) mutant. BdPYL1 T-DNA mutant exhibited clear ABA hyposensitivity phenotypes during seedling establishment and in mature plants. Single receptor predominance is in agreement with high transcriptional abundance of only a small Brachypodium ABA receptors subset, harboring the higher marginal significance of BdPYL1. Our findings suggest that unlike the highly redundant ABA core signaling components of Arabidopsis, Brachypodium encompasses a more compact and specialized ABA receptor apparatus. This organization may contribute to plant adaptations to ecological niches. These results lay the groundwork for targeting the prominent ABA receptors for stress perception in grasses, and reveal functional differences and commonalities between monocots and eudicots.