Highly efficient microwave-assisted one-pot synthesis of 4-aryl-2-aminothiazoles in aqueous medium

The thiazole ring system is one of the most important heterocycles in nature, as it represents an important structural motif of many biological compounds, including vitamin B₁ (Thiamin), carboxylase and penicillin. There is, therefore, an urgent need to design rapid, efficient and environmentally benign protocols for the synthesis of thiazoles. Herein, we have developed a one-pot protocol for the synthesis of 4-aryl-2-aminothiazoles from the reaction of aromatic ketones, NBS (N-Bromosuccinimide) and thioureas under microwave irradiation at 80–85 °C in PEG (polyethylene glycol)-400 and water as a green reaction medium. The products were obtained in 84–89% yields in 28–32 min. The method has several advantages such as use of green solvent, easy work-up, excellent yield and avoiding use of lachrymatric α-haloketones.     

Properties,synthesis and toxicity of silver nanoparticles

Silver nanoparticles are actually used in several industrial sectors and end up in the environment, thus inducing a possible toxicity for living organisms. This article reviews the properties, synthesis and toxicology of silver nanoparticles, with focus on the toxicity for insects such as Bombyx mori.     

Laboratory investigation of <Emphasis Type="Italic">Fallopia</Emphasis> × <Emphasis Type="Italic">bohemica</Emphasis> fruits dispersal by watercourses

Seed and fruit dispersal along watercourses favours the long-distance migration of invasive species, not only for aquatic or wetland species, but also for terrestrial wind-dispersed plants, like the Japanese knotweed. The present paper aims at investigating the role of watercourses in the dispersal of the knotweed due to its frequent occurrence on riverbanks and production of fertile achenes (type of fruit of the Japanese knotweed). This dispersal occurs along two steps after the fruits deposit on the water surface: floatation first and then sinking towards the bottom of the watercourse. Regarding the first step, the effects of agitation of the water, temperature, surface tension and luminosity on the achenes floatability are experimentally studied. While no influence of luminosity is observed, an increase of temperature greatly decreases the floating time. Floating time also decreases as the contact between water and the fruit is enhanced (through submersion of achenes, agitation of the water or lower surface tension). Regarding the second step, the fall velocity of the fruits in water at rest is measured and appears to be independent of the seed history (floating time). 3D helical motions are systematically observed with constant tangential velocity with respect to the falling velocity. The trajectory of the fruits in a shear flow is then measured and the evolution of their velocity components along the sinking process is discussed. Finally, the contribution of both steps to the long-distance migration of the seeds is estimated.     

Are breaking waves,bores, surges and jumps the same flow?

The flow structure in the aerated region of the roller generated by breaking waves remains a great challenge to study, with large quantities of entrained air and turbulence interactions making it very difficult to investigate in details. A number of analogies were proposed between breaking waves in deep or shallow water, tidal bores and hydraulic jumps. Many numerical models used to simulate waves in the surf zone do not implicitly simulate the breaking process of the waves, but are required to parameterise the wave-breaking effects, thus relying on experimental data. Analogies are also assumed to quantify the roller dynamics and the energy dissipation. The scope of this paper is to review the different analogies proposed in the literature and to discuss current practices. A thorough survey is offered and a discussion is developed an aimed at improving the use of possible breaking proxies. The most recent data are revisited and scrutinised for the use of most advanced numerical models to educe the surf zone hydrodynamics. In particular, the roller dynamics and geometrical characteristics are discussed. An open discussion is proposed to explore the actual practices and propose perspectives based on the most appropriate analogy, namely the tidal bore.     

Large eddy simulation of flow and scalar transport in a vegetated channel

Predicting flow and mass transport in vegetated regions has a broad range of applications in ecology and engineering practice. This paper presents large eddy simulation (LES) of turbulent flow and scalar transport within a fully developed open-channel with submerged vegetation. To properly represent the scalar transport, an additional diffusivity was introduced within the canopy to account for the contribution of stem wakes, which were not resolved by the LES, to turbulent diffusion. The LES produced good agreement with the velocity and concentration fields measured in a flume experiment. The simulation revealed a secondary flow distributed symmetrically about the channel centerline, which differed significantly from the circulation in a bare channel. The secondary circulation accelerated the vertical spread of the plume both within and above the canopy layer. Quadrant analysis was used to identify the form and shape of canopy-scale turbulent structures within and above the vegetation canopy. Within the canopy, sweep events contributed more to momentum transfer than ejection events, whereas the opposite occurred above the canopy. The coherent structures were similar to those observed in terrestrial canopies, but smaller in scale due to the constraint of the water surface.     

Heavy metals in soils from a typical industrial area in Sichuan,China: spatial distribution,source identification,and ecological risk assessment

Anthropogenic activities could result in increasing concentrations of heavy metals in soil and deteriorating in soil environmental quality. Topsoil samples from a typical industrial area, Shiting River Valley, Sichuan, Southwest China, were collected and determined for the concentrations of Cu, Zn, Cr, Cd, As, and Hg. The mean concentrations of these metals were lower than the national threshold values, but were slightly higher than their corresponding background values, indicating enrichment of these metals in soils in the valley, especially for Cu, Zn, and Hg. The topsoils in this area demonstrated moderate pollution and low potential ecological risk. Principal component analysis coupled with cluster analysis was applied to analyze the data and identified possible sources of these heavy metals; the results showed that soil Cd, Hg, As, Cu, and Zn were predominantly controlled by human activities, whereas Cr was mainly from the parent material. The spatial distribution of the heavy metals varied distinctly and was closely correlated to local anthropogenic activities. Furthermore, the concentrations of heavy metals in the industrial land demonstrated relatively higher levels than those of other land use patterns. Soil metal concentrations decreased with the distance increase from the traffic highway (0–1.0 km) and water system (0–2.0 km). Additionally, soil properties, especially pH and soil organic matter, were found to be important factors in the distribution and composition of metals.     

The Influence of Landscape Patterns on the Bird Diversity of Four Urban Parks

In our study, we aimed to investigate the influence of landscape patterns on the diversity of birds in four urban parks. The parks are located in a region that has a high value of regional biodiversity and is also highly urbanized (Jundiai, state of São Paulo [SP], in Southeastern Brazil). Using a set of aerial photos, the surrounding landscape was divided into two regions (rings) and corresponding landscape metrics were calculated. The presence of bird species was recorded monthly over a one‐year period and classified according to selected ecological criteria. The land cover of the areas surrounding each park was primarily buildings and residences. Bird diversity was significantly correlated with the presence/proximity of water bodies. We state that the potential of the parks to harbor bird species is not negligible. Managing the area surrounding a park to increase the percentage of forested area and the size of forest fragments is as crucial as managing the core park area, especially for improving its attractiveness for new bird species.     

Animal Killing and Postdomestic Meat Production

The act of animal killing affects the human psyche in manners that are culturally contingent. Throughout history, societal attitudes towards the taking of animal lives have mostly been based on deference and/or dominion. Postdomestic societies have evolved in fundamentally different ways. Meat production is abundant yet concealed, animals are categorized and stereotyped, and slaughter has become a highly disquieting activity. Increased awareness of postdomestic meat production systems raises a moral polemic and provokes disgust in some consumer segments. Overall, a heterogeneous set of solutions has emerged to deal with the societal upset and cognitive dissonance caused by animal slaughter. This includes the so-called carnism approach, a rise in animal welfare programs, a market demand for reassuring narratives (“story meat”), a rehabilitation of the metier of farmers and butchers, crowd butchering, neo-ritualism and home slaughter, the biotechnological exploration of “cultured meat” and “pain-free meat”, entomophagy, “meatless meat”, and the increasing proliferation of vegan and vegetarian lifestyles.     

Can pine needles indicate trends in the air pollution levels at remote sites?

Data from ten years of integrated monitoring were used here to evaluate whether pine needles are a feasible tool for an assessment of long-term trends of the atmospheric contamination. Pine needles collected once a year were compared to high volume air samples collected for 24 h, every 7 days, and passive air samples integrated over 28-day periods. Results showed the same concentration patterns of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) captured in needles and high volume samples. Passive air samplers were less efficient in sampling the particle-bound compounds. Theoretical air volume equivalent to each needle sample (V_EQ) was calculated as a ratio of the needle concentration over the mean air concentration. Results indicated different equivalent volumes for PAHs and organochlorines, possibly due to the faster degradation rates of PAHs in needles. The most important finding is that in the long term a needle monitoring gives very similar information on temporal trends of the atmospheric pollution as does a high volume air monitoring.     

Occurrence and behaviour of selected hydrophobic alkylphenolic compounds in the Danube River

Six hydrophobic alkylphenolic compounds were investigated for the first time simultaneously in four different matrices in the Danube River. Maximum sediment concentrations were 2.83, 2.10, 0.28, and 0.035 mg kg⁻¹ for nonylphenol, nonylphenol monoethoxylate, nonylphenol diethoxylate and octylphenol. Maximum levels in suspended particulate matter (SPM) were 0.18, 0.12, 0.10, and 0.003 mg kg⁻¹. No correlation between concentrations in SPM and sediments was found. Octylphenol monoethoxylate and octylphenol diethoxylate were recorded only in sediment at one location. In mussels and water only nonylphenol and octylphenol were found. Nonylphenol concentrations in mussels (up to 0.34 mg kg⁻¹) correlate with concentrations found in SPM and indicate a slight bioaccumulation. Concentrations in water were close to the limit of quantification. We assume in situ formation of nonylphenol monoethoxylate and nonylphenol in sediments at some locations. In some cases nonylphenol in sediments exceeded the provisional EU environmental quality standards.