A laboratory investigation was conducted to determine whether colloidal suspensions of inorganic nanoparticulate materials of natural or industrial origin in the external water supplied to the primary root of maize seedlings (Zea mays L.) could interfere with water transport and induce associated leaf responses. Water flow through excised roots was reduced, together with root hydraulic conductivity, within minutes of exposure to colloidal suspensions of naturally derived bentonite clay or industrially produced TiO2 nanoparticles. Similar nanoparticle additions to the hydroponic solution surrounding the primary root of intact seedlings rapidly inhibited leaf growth and transpiration. The reduced water availability caused by external nanoparticles and the associated leaf responses appeared to involve a rapid physical inhibition of apoplastic flow through nanosized root cell wall pores rather than toxic effects. Thus: (1) bentonite and TiO2 treatments also reduced the hydraulic conductivity of cell wall ghosts of killed roots left after hot alcohol disruption of the cell membranes; and (2) the average particle exclusion diameter of root cell wall pores was reduced from 6.6 to 3.0 nm by prior nanoparticle treatments. Irrigation of soil-grown plants with nanoparticle suspensions had mostly insignificant inhibitory effects on long-term shoot production, and a possible developmental adaptation is suggested.

Humic acids are ubiquitous, organic-endproducts of the chemical and microbial degradation of dead biota in soils throughout the world. Humic acids can be transported in soil water as heterogeneous, supra-molecular, colloidal-agglomerates. Humic acid accumulation in the rhizosphere of transpiring plants may chemically stimulate development by increasing root availability of mineral nutrients and/or growth regulatory biomolecules. This report introduces novel, physical mechanisms by which humic acid can also reduce plant development. Effects of humic acid addition to the root media of intact maize plants (Zea mays L.) on their growth, transpiration and resistance to water deficits were assayed, as were the effects of external humic acid on the hydraulic conductivity of excised primary-roots. Humic acid reduced shoot growth, transpiration and resistance to water stress but not root growth. Root hydraulic conductivity was reduced by up to 44% via a time-, concentration-and size-dependent fouling mechanism resulting from humic acid accumulation at root cell-walls. Thus, humic acid is shown, apparently for the first time, to be able to exert novel physical effects in addition to its known chemical effects on plant development.

A novel conjugate of docetaxel and biotin (designated as IDD-1010) was designed and chemically synthesized via an ester linkage at position 2’ carbon in docetaxel. The synthesized pure IDD-1010 exhibits a potent anti-cancer activity in in vitro and in vivo studies. At 10 nM, IDD-1010 has induced increased apoptosis and mitotic arrest of PC3-Luc prostate cancer cells, causing aneuploidy and cell death at higher concentrations. Toxicology studies indicate that the maximal tolerated dose (MTD) of IDD-1010 is 150 mg/kg in mice; equivalent to about 12.2 mg/kg of body weight, or to about an 850 mg dose for a patient weighing 70 kg. The MTD-treated mice exhibited weight gain similar to that of the control group, with no gross pathological signs at 14 days post-dosing. At a lower dose, IDD-1010 treatment did not lead to any significant weight loss in mice, although decreased the tumor volume stemming from injecting cancer cells into the dorsal loop of mouse prostate, and it was found to be more potent than Paclitaxel (reference drug). Similarly, IDD-1010 treatment significantly reduced tumor weight and thereby increased the percentage of mice survival as compared to reference drug-treated and control groups. To summarize, the described experiments using IDD-1010, as compared to the reference drug, strongly suggest a potential treatment utility with a wider therapeutic window for prostate cancer. Henceforth, clinical research on such a novel drug candidate would be greatly worthwhile.

This study examined Arab high-school students' decision-making ability (their cognitive level) regarding a sea turtle conservation issue in relation to three independent variables: the proximity of their residence to the sea, the type of residence (city or village), and their gender. The study population consisted of tenth-grade students in high schools from the Arab sector: from urban localities, rural localities, localities close to the sea, and localities far from the sea. The main findings of the study are as follows: (1) The average Arab student's decision-making ability is low. Most Arab students were found to have a low cognitive level. (2) A clear difference exists between students from localities close to the sea and those far from the sea. Students from localities close to the sea had greater decision-making ability. (3) A clear difference exists between students from urban localities and those from rural localities. Students from urban areas had more decision-making ability. A significant difference exists between boys and girls: girls had more decision-making ability. The main conclusion from the study is that the cognitive level of Arab students' decision-making ability in the context of sea turtle conservation is low. This finding indicates that traditional teaching in the Arab education system does not promote, develop, and improve this ability. Most of the time the teacher asks questions and is situated in the center of the activity. Students noted that their teachers tend to involve them in lessons, but not enough in class discussions.

No abstract