פרסומים

Clay mineral properties, together with solution chemistry, control the assembly of clay platelets into hierarchical structures, including tactoids and aggregates. We studied the effect of salinity on the assembly of kaolinite, illite, and montmorillonite at three critical scales: platelet, tactoid, and aggregate, using cryogenic scanning electron microscopy (cryo-SEM), atomic force microscopy (AFM) and cryo-transmission EM (cryo-TEM), respectively. Cyro-SEM images coupled with original alignment analysis indicate that the degree of aggregate alignment in an ionized solution was significantly higher than in deionized water. Furthermore, upon increasing platelet-platelet bonding energy (montmorillonite > illite > kaolinite), tactoid size increased, packing was less ordered, and aggregate alignment decreased. AFM measurements showed that an increase in ionic-strength caused a decrease in the Young's modulus of the clays, indicating higher tactoid alignment, since, disordered structures, comprising various platelet orientations, are stiffer than highly-aligned structures. We successfully measured distances <1 nm, for both kaolinite and montmorillonite by cryo-TEM, directly demonstrating that increasing ionic-strength reduces platelet-platelet distances. The outcome of this study offers a new approach and methodology to study fundamental colloid-assembly which will trigger future studies investigating additional parameters affecting assembly such as, temperature, solution pH, natural organic matter, and anthropogenic activity. (C) 2020 Elsevier Inc. All rights reserved.

The capability of unmanned aerial vehicle (UAV) spectral imagery to assess maize yield under full and deficit irrigation is demonstrated by a Tetracam MiniMCA12 11 bands camera. The MiniMCA12 was used to image an experimental field of 19 maize hybrids. Yield prediction models were explored for different maize development stages, with the best model found using maize plant development stage reproductive 2 (R2) for both maize grain yield and ear weight (respective R2 values of 0.73 and 0.49, and root mean square error of validation (RMSEV) values of 2.07 and 3.41 metric tons per hectare using partial least squares regression (PLS-R) validation models). Models using vegetation indices for inputs rather than superspectral data showed similar R2 but higher RMSEV values, and produced best results for the R4 development stage. In addition to being able to predict yield, spectral models were able to distinguish between different development stages and irrigation treatments. These abilities potentially allow for yield prediction of maize plants whose development stage and water status are unknown.

Obesity has been traditionally viewed as a protective factor for fractures. Recent studies have challenged this concept, particularly regarding abdominal obesity. We aimed to investigate the association between abdominal obesity, body mass index (BMI) and fragility fractures prevalence in a sample of community-dwelling elderly Israeli women.

Cationic molecules are found in abundance as antimicrobial agents with a well-defined mechanism of action and significant therapeutic benefits. Quaternary ammonium-containing compounds are frequently employed due to their facile synthesis and tunable properties. Over time, however, bacterial resistance to these compounds has become a significant obstacle. We report here a series of asymmetric trisalkylamine cyclopropenium cationic derivatives as chemical isosteres of quaternary ammonium compounds, capable of strong antimicrobial activity and overcoming microbial resistance. These small molecules were prepared by one-pot reaction of tetrachlorocyclopropene (TCC) with unhindered secondary amines in the presence of Hünig's base. In this work we describe the synthesis, purification, and characterization of five trisamino-cyclopropenium derivatives and confirm their structures by spectral analysis and mass-spectrometry. Three of the compounds displayed considerable antimalarial activity (IC(50) < 0.1 µM) without demonstrating significant toxic effects in vitro (TC(50) > 1 µM). This class of cyclopropenium-based compounds provides an opening for the discovery of potent and non-toxic antimicrobial agents.

Cationic molecules are found in abundance as antimicrobial agents with a well-defined mechanism of action and significant therapeutic benefits. Quaternary ammonium-containing compounds are frequently employed due to their facile synthesis and tunable properties. Over time, however, bacterial resistance to these compounds has become a significant obstacle. We report here a series of asymmetric trisalkylamine cyclopropenium cationic derivatives as chemical isosteres of quaternary ammonium compounds, capable of strong antimicrobial activity and overcoming microbial resistance. These small molecules were prepared by one-pot reaction of tetrachlorocyclopropene (TCC) with unhindered secondary amines in the presence of Hünig's base. In this work we describe the synthesis, purification, and characterization of five trisamino-cyclopropenium derivatives and confirm their structures by spectral analysis and mass-spectrometry. Three of the compounds displayed considerable antimalarial activity (IC(50) < 0.1 µM) without demonstrating significant toxic effects in vitro (TC(50) > 1 µM). This class of cyclopropenium-based compounds provides an opening for the discovery of potent and non-toxic antimicrobial agents.

Purpose: Guardianship of people with disabilities has been under growing scrutiny, leading some welfare states to offer supported decision-making as a legal alternative. This study examined the attitudes of Israeli social work students toward guardianship and supported decision-making and the relationship between these attitudes and the perceived importance of social work goals, as mediated by perceptions of disability. Materials and methods: Participants were 414 undergraduate and graduate level social work students from Israel. Participants completed a structured questionnaire that measured: attitudes toward guardianship and supported decision-making, importance of social work goals, and perception of disability. Results: Although social work students tended to support limiting the scope of guardianship, they did not clearly oppose it. Individual model perspective of disability mediated the association between the social work goal of social control and attitudes toward guardianship. Social model perspective of disability mediated the association between the social work goal of social justice and attitudes toward guardianship. Conclusion: To reduce guardianship appointments, social work educators should educate students better regarding current supported decision-making trends, emphasize the importance of social justice goals, and discuss critically the necessity of social control. Further, educators need to embrace the social model of disability, in particular its view of autonomy and interdependence.Implications for rehabilitation The UN Convention on the Rights of Persons with Disabilities has urged limiting guardianship practices, and developing instead less restrictive alternatives, especially supported decision making. In order to fully implement the Convention’s vision, efforts must be placed in social work training programs on discussing the limitations of guardianship, the dilemmas it raises and the advantages of other less restrictive alternatives, including that of supported decision-making. Social work educators should also emphasize the importance of social justice goals and discuss critically the necessity of social control. Similar emphasis should be placed on exposing students to the social model of disability, including its view of autonomy and interdependence.