Occurrence of Fusarium mycotoxins in freshly harvested highland barley (qingke) grains from Tibet, China.

Highland barley, also called "qingke" in Tibetan, is mainly cultivated in the Tibetan Plateau of China and has been used as a major staple food for Tibetans. Recently, Fusarium head blight (FHB) of qingke was frequently observed around the Brahmaputra River in Tibet. Considering the importance of qingke for Tibetans, the assessment of Fusarium mycotoxin contamination is essential for food safety. In this study, a total of 150 freshly harvested qingke grain samples were obtained from three regions around the Brahmaputra River in Tibet (China) in 2020. The samples were investigated for the occurrence of 20 Fusarium mycotoxins using high-performance liquid chromatography-tandem mass spectrometry (HPLC‒MS/MS). The most frequently occurring mycotoxin was enniatin B (ENB) (46%), followed by enniatin B1 (ENB1) (14.7%), zearalenone (ZEN) (6.0%), enniatin A1 (ENA1) (3.3%), enniatin A (ENA) (1.3%), beauvericin (BEA) (0.7%), and nivalenol (NIV) (0.7%). Due to the increase in altitude, the cumulative precipitation level and average temperature decreased from the downstream to the upstream of the Brahmaputra River; this directly correlated to the contamination level of ENB in qingke, which gradually decreased from downstream to upstream. In addition, the level of ENB in qingke obtained from qingke-rape rotation was significantly lower than that from qingke-wheat and qingke-qingke rotations (p < 0.05). These results disseminated the occurrence of Fusarium mycotoxins and provided further understanding of the effect of environmental factors and crop rotation on Fusarium mycotoxins.

Ambipolar transport in narrow bandgap semiconductor InSb nanowires.

We report on a transport measurement study of top-gated field effect transistors made out of InSb nanowires grown by chemical vapor deposition. The transistors exhibit ambipolar transport characteristics revealed by three distinguished gate-voltage regions: In the middle region where the Fermi level resides within the bandgap, the electrical resistance shows an exponential dependence on temperature and gate voltage. With either more positive or negative gate voltages, the devices enter the electron and hole transport regimes, revealed by the resistance decreasing linearly with decreasing temperature. From the transport measurement data of a 1 µm-long device made from a nanowire of 50 nm in diameter, we extracted a bandgap energy of 190-220 meV. The off-state current of this device is found to be suppressed within the measurement noise at a temperature of T = 4 K. A shorter, 260 nm-long device is found to exhibit a finite off-state current and a circumference-normalized on-state hole current of 11 µA µm-1 at VD = 50 mV which is the highest for such a device to our knowledge. The ambipolar transport characteristics make the InSb nanowires attractive for CMOS electronics, hybrid electron-hole quantum systems and hole based spin qubits.

Field investigation of advanced oxidation of secondary effluent from municipal wastewater treatment plant.

Successful treatment of the secondary effluent ensures its safe disposal and water reclamation for water reuse. To understand the effect of ultraviolet (UV) irradiation in combination with hydrogen peroxide (H(2)O(2)) on secondary effluent under field conditions, an advanced oxidation system, UV+H(2)O(2), was installed and fed with the effluent at 1.0, 1.5 and 2.0 m(3) h(- 1) over a period of 6 months. The electrical energy density for the UV reactor was varied between 0.5 and 5.2 kWh m(-3) and H(2)O(2) added at concentrations of 0, 13 or 26 mg L(-1). The feed and product water samples were taken periodically and analyzed for biological (heterotrophic plate count-HPC, total and fecal coliform-TC and FC) and chemical (NH(4)(+)-N, NO(3)(-)-N, NO(2)(-)-N and total organic carbon-TOC) parameters. For the treatment of UV+26 mg L(- 1) H(2)O(2), flow rates of 1.0, 1.5 and 2.0 m(3) h(- 1) resulted in > 4-log removal of HPC with a maximum survivor of 20 CFU mL(-1) and > 4 log reduction of FC with a survivor of 8 CFU (100 mL)(- 1). The electrical energy density of 1.5 kWh m(-3) was optimum for the inactivation. The NO(2)(-)-N concentrations of the product water were 0.09-0.42 mg L(- 1) compared with 0.04-0.09 mg L(- 1)in the feed. With or without H(2)O(2) addition, NO(2)(-)-N concentration increased with increases in UV electrical energy density. The highest increase in NO(2)(-)-N was associated with the maximum energy density of 5.2 kWh m(-3). Increase in H(2)O(2) dose reduced NO(3)(-)-N concentration by 2.0 to 5.7%. The overall results showed that the advanced oxidation technology prepared the effluent for safe disposal and/or for water reclamation for reuse.

Molecular cloning and expression analysis of a novel CONSTANS-like gene from potato.

A full-length cDNA of a StCONSTANS-like (StCOL) gene was cloned from potato (Solanum tuberosum L.) by RT-PCR and RACE. The predicted amino acid sequence of this cDNA has a high degree of identity with other homologous members of the CO or COL family. Analysis of mRNA levels for StCOL shows that it is highly expressed in leaves and becomes weaker during tuberization; moreover, is independent of gibberellin A(3) and sucrose.

Permeate flux optimisation of a pilot microfiltration plant for cost-effectiveness of water reclamation for reuse.

A pilot plant was constructed with eight elements of an Asahi microfiltration (MF) membrane-a total filtration surface area of 56 m2. Performance of the plant was examined in preparation of a secondary sewage effluent without coagulant for reverse osmosis membrane treatment. Production at different permeate flux was tested for evaluation of the changes in transmembrane pressure (TMP) and specific permeate flux (SPF) with time. Clean-in-place (CIP) was conducted when TMP reached a value about 2 atm after each test. For permeate flux of 48, 55, 61 and 66 L m-2 h-1, the ceiling TMP was reached after filtration for approximately 420, 200, 225, and 195 h, respectively. The corresponding cumulative permeate volumes were 1130, 620, 765, 720 m3 before a CIP was necessary. The SPF decreased quickly with increases in permeate flux and the corresponding half-SPF times were 147, 89, 75 and 39 h for the respective flux studied. The membrane fouling tolerance was greater at a lower than at a higher flux. Analysis of the performance data suggests that run of the MF plant at higher permeate flux with more frequent and quick CIP might produce more water. The optimal filtration durations were found to be 12, 8, 7 and 3 days for permeate flux of 48, 55, 61 and 66 L m-2 h-1, respectively. Prolonged filtration after the optimal interval without CIP may not maximise the economical benefit.

TEM investigations on ZnO nanobelts synthesized via a vapor phase growth.

Unusual ZnO nanostructures have been successfully synthesized via selenium-controlled chemical vapor phase growth on Si (111) substrates at about 500 degrees C. The microstructure and chemical compositional characteristics of the ZnO nanomaterials have been systematically investigated by means of analytical transmission electron microscopy (TEM), including energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy. Most of the nanostructures have a belt-like morphology with typical widths of approximately 150 nm and lengths up to several micrometers. All the investigated materials are found to be stoichiometric ZnO with a hexagonal crystal structure. The growth directions for the nanobelts are found to be [1010] and [2110] respectively. Regular-triangle and needle-like heads with diameters only approximately 25-35 nm have been found in the straight nanobelts. High-resolution TEM images indicate that all the nanostructures are single crystals and free of defects. The growth mechanisms of such interesting and unique morphologies are briefly discussed.