Acute and subchronic effects of petroleum on the freshwater fish Hoplias aff. malabaricus

Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage (< 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

A preliminary study of improving the MICP effects via the extractions from seashell nacre

In microbially induced calcium carbonate precipitation (MICP) process, it is the precipitated CaCO3 that cements loose sand particles together to improve their mechanical properties. Seashell nacre composed of CaCO3 is a natural product, which is worth researching for its great hardness, strength, and toughness. However, there is no study connecting this natural nacre mineralization with MICP. Therefore, a precedent herein is established to modify the MICP process via the water-soluble matrix (WSM) extracted from nacre, where WSM contributes to the great mechanical properties of nacre. Correspondingly, this study examines the effects of WSM with different concentrations on urease activity and strength as well as microstructure of bio-cemented sand samples. The experimental results show that a small number of WSM (50mg/L) can improve the average strength of bio-cemented sand samples 1.5 times. This is because 50mg/L WSM can significantly improve the urease activity of bacteria meanwhile increasing the Ca2+ utilization rate. Thus, more CaCO3 crystals are precipitated, and the higher UCS of bio-cemented sand samples is achieved. Moreover, the XRD results indicate that the precipitated CaCO3 is almost calcite, and only a little aragonite is detected when the concentration of WSM increases to 100mg/L. Additionally, the SEM images demonstrate that WSM involvement can affect the shapes and sizes of CaCO3 crystals. Overall, this work is an unprecedented exploration imitating nacre that hopefully paves way for future studies.

Nutrient variability of rice landraces (Oryza sativa L.) from Manipur, Northeast India and its nutrients supply potential in rice-based diets

Purpose Rice landraces are essential for supplying beneficial traits for developing improved rice varieties with better nutritional quality. Nevertheless, in a yield-driven environment, grain nutritional quality has been ignored especially that of rice landraces. Given this, the purpose of this study is to evaluate the content and nutritional variability of rice landraces from Manipur. Design/methodology/approach Thirty-three most popular rice landraces were collected as dry paddy samples from Manipur and transported to the National Institute of Nutrition, Hyderabad, by air. All the paddy samples were processed and analyzed for 35 nutrient parameters using standard methodologies. Findings The mean nutrient content of Nagaland brown rice was: protein 7.5 ± 0.8, fat 3.0 ± 0.3, TDF 5.5 ± 0.4 and ash 1.2 ± 0.2 g/100g. The range of water soluble-vitamin content in mg/100g, was 0.1–0.43 for Thiamine and for Niacin 2.1–3.5, while the content in µg/100g was 40–64 for Riboflavin, 0.5–3.9 for Pantothenic acid and 20–118 for Pyridoxine. A relatively large coefficient of variation was observed for iron (25%), manganese (28%), copper (32%), calcium (13%) and phosphorus (11%). Manipur rice landraces have significantly higher total dietary fiber and lower phytate contents than modern varieties. Milling led to steep losses of nutrients, and limiting to 5% milling substantially improves nutrient retention in milled rice. Research limitations/implications Future nutrition interventions should use rice with superior nutrient quality to improve nutrient intakes. Manipur rice landraces conserved over generations can broaden the genetic base of breeding stocks especially in the face of climate change. Originality/value The paper presents comprehensive nutritional data of 33 rice landraces from the state of Manipur, India. The results indicate large nutrient variability even within these 33 rice landraces with important traits such as high total dietary fiber and low phytate contents. The study highlights the importance of conserving the existing rich genetic material of Manipur rice landraces to develop varieties that combine higher yields with stress tolerance and superior grain nutritional value to improve the food and nutrient security.

Measurement Report: Optical properties and sources of water-soluble brown carbon in Tianjin, North China: insights from organic molecular compositions

Brown carbon (BrC) aerosols exert vital impacts on climate change and atmospheric photochemistry due to their light absorption in the wavelength range from near-ultraviolet (UV) to visible light. However, the optical properties and formation mechanisms of ambient BrC remain poorly understood, limiting the estimation of their radiative forcing. In the present study, fine aerosols (PM2.5) were collected during 2016–2017 on a day/night basis over urban Tianjin, a megacity in North China, to obtain seasonal and diurnal patterns of atmospheric water-soluble BrC. There were obvious seasonal but no evident diurnal variations in light absorption properties of BrC. In winter, BrC showed much stronger light absorbing ability since mass absorption efficiency at 365 nm (MAE365) (1.54 ± 0.33 m2 g−1), which was 1.8 times larger than that (0.84 ± 0.22 m2 g−1) in summer. Direct radiative effects by BrC absorption relative to black carbon in the UV range were 54.3 ± 16.9 % and 44.6 ± 13.9 %, respectively. In addition, five fluorescent components in BrC, including three humic-like fluorophores and two protein-like fluorophores were identified with excitation-emission matrix fluorescence spectrometry and parallel factor (PARAFAC) analysis. The lowly-oxygenated components contributed more to winter and nighttime samples, while more-oxygenated components increased in summer and daytime samples. The higher humification index (HIX) together with lower biological index (BIX) and fluorescence index (FI) suggest that the chemical compositions of BrC were associated with a high aromaticity degree in summer and daytime due to photobleaching. Fluorescent properties indicate that wintertime BrC were predominantly affected by primary emissions and fresh secondary organic aerosol (SOA), while summer ones were more influenced by aging processes. Results of source apportionments using organic molecular compositions of the same set of aerosols reveal that fossil fuel combustion and aging processes, primary bioaerosol emission, biomass burning, and biogenic and anthropogenic SOA formation were the main sources of BrC. Biomass burning contributed much larger to BrC in winter and at nighttime, while biogenic SOA contributed more in summer and at daytime. Especially, our study highlights that primary bioaerosol emission is an important source of BrC in urban Tianjin in summer.