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Fungal secondary metabolites play important roles not only in fungal ecology but also in humans living as beneficial medicine or harmful toxins. In filamentous fungi, bZIP-type transcription factors (TFs) are associated with the proteins involved in oxidative stress response and secondary metabolism. In this study, a connection between a bZIP TF and oxidative stress induction of secondary metabolism is uncovered in an opportunistic pathogen Aspergillus flavus, which produces carcinogenic and mutagenic aflatoxins. The bZIP transcription factor AflRsmA was identified by a homology research of A. flavus genome with the bZIP protein RsmA, involved in secondary metabolites production in Aspergillus nidulans. The AflrsmA deletion strain (ΔAflrsmA) displayed less sensitivity to the oxidative reagents tert-Butyl hydroperoxide (tBOOH) in comparison with wild type (WT) and AflrsmA overexpression strain (AflrsmAOE), while AflrsmAOE strain increased sensitivity to the oxidative reagents menadione sodium bisulfite (MSB) compared to WT and ΔAflrsmA strains. Without oxidative treatment, aflatoxin B1 (AFB1) production of ΔAflrsmA strains was consistent with that of WT, but AflrsmAOE strain produced more AFB1 than WT; tBOOH and MSB treatment decreased AFB1 production of ΔAflrsmA compared to WT. Besides, relative to WT, ΔAflrsmA strain decreased sclerotia, while AflrsmAOE strain increased sclerotia. The decrease of AFB1 by ΔAflrsmA but increase of AFB1 by AflrsmAOE was on corn. Our results suggest that AFB1 biosynthesis is regulated by AflRsmA by oxidative stress pathways and provide insights into a possible function of AflRsmA in mediating AFB1 biosynthesis response host defense in pathogen A. flavus.

Although high F− groundwater was observed in the Hengshui of the North China Plain, the depth dependence of groundwater F− and its relation to aquifer sediments remains unknown. Both shallow groundwater and deep groundwater were collected for chemical and isotopic characterization. Sediments were taken from different depths down to 130 m for total element analysis and F− form determination with sequential extraction procedure. Results show that F− concentration ranges from 0.37 to 3.28 mg/L, and from 0.28 to 3.6 mg/L in shallow and deep groundwater, respectively. High F− water from shallow aquifers are of Cl–SO4–Na–Mg, HCO3–Cl–SO4–Na and SO4–Cl–Na–Mg types, while HCO3–SO4–Cl–Na and Cl–SO4–Na types are from deep aquifers. High F− waters are mainly found at the depths of 50, 200 and 300 m. Along the flow path, groundwater shows an increasing trend in F− concentration from the northwest to the southeast. Isotopes of 18O and D in deep groundwater are more depleted in comparison with shallow groundwater, suggesting that shallow and deep groundwater replenish through different ways with longer retention time of deep groundwater. δ13C of dissolved inorganic carbon are between −11.9 and −8.8 ‰ in shallow groundwater and between −10.6 and −7.5 ‰ in deep groundwater, respectively, which indicates that groundwater DIC comes from both rock weathering and biodegradation of organic matter. Fluoride content in the sediment ranges from 140 to 1690 mg/kg, showing a decreasing trend with depth. Good correlations between F− and Al2O3 and Fe2O3 are observed, demonstrating that F− contents in sediments are significantly influenced by the minerals containing Fe2O3 and Al2O3 in terms of adsorption. Sequential extraction procedure shows that exchangeable F− form (F1) and Fe–Mn oxides-bound F− (F3) generally decrease with depths, while organic matter or sulfide-bound F− (F4) keeps relatively stable and carbonate-bound F− (F2) exhibits highly variable. The relationships between F− concentration and Fe or Mn imply that F− in F1 is more inclined to be scavenged by Fe and Mn oxides/hydroxides which have a stronger affinity for F−. Although a variety of hydrogeochemical processes affected F− concentrations, dissolution–precipitation is a vital process in the study area. In comparison with shallow groundwater, cation exchange may exhibit more significantly effect on F− enrichment in deep groundwater. Competitive adsorption of HCO3 − and OH− with F− leads to the release of F− from aquifer matrix into solution, which increases groundwater F− concentration. Evaporation is another control on F− concentration, especially in shallow groundwater.

Nowadays, inhabitants living in rural areas of northern China still rely on traditional heating methods, such as kangs (bed-stoves), radiators heated by mini stoves, and burning caves in cold winter period. Burning caves are increasingly used due to free fuels from crop wastes, simple structures, and better heating effect than kangs and mini stoves. In this study, field measurements of indoor environment in several rural houses with burning caves designed by local craftsmen and located in northern China were carried out in 2010–2011. The results show that indoor temperatures maintained at above 18 °C and it was felt more comfortable than houses heated by kangs and mini stoves. To solve some existing problems in houses with burning caves built by local craftsmen, a new house integrated with an improved burning cave was built in December 6, 2011. The results from theoretical analysis and field measurements showed that temperature difference between adjacent rooms could be reduced by 4–6 °C, which is 2–5 °C lower than the houses with the burning caves designed by craftsmen, and the thermal efficiency reached 56.7%. In addition, the concentration of CO was reduced to 1/5 of the value in the houses with burning caves by local craftsmen.

An utterance of a language often demonstrates the effect of declination, usually understood broadly as a reduction in certain physical or acoustic signals. Previous research on declination focuses primarily on the acoustic measures of pitch (such as the movement of pitch or the alternation of pitch span) or intensity. Neglected in the matter is the third acoustic dimension of speech duration. This paper reports on an experiment on declination focusing on pitch duration. The language studied is Mandarin Chinese. Six native Mandarin speakers are recruited. A total of 864 utterances of 2-to-9 syllables in four tones and four functional intonations are recorded and analyzed on Praat. The results show that the declination of pitch duration goes side by side along the pitch declination, both of which share the same physiological basis. Specifically, (1) the average pitch duration within the prosodic unit decreases gradually from the sentence-initial prosodic unit to the sentence-final one, (2) the pitch duration of the left-most syllable of the prosodic unit decreases gradually from the sentence-initial prosodic unit to the sentence-final one, and (3) the pitch duration of the right-most syllable of the prosodic unit decreases slightly from the sentence-initial prosodic unit to the sentence-final one.