Kinetics of Fe(III) reduction by ascorbic acid in aqueous solutions

The reaction of Fe(III) and ascorbic acid (AA) in food products and digestive tracts affects the efficiency and uptake of these two nutrients. We investigated the kinetics of Fe(III) reduction by AA at pH 5 and 6 in a model system at 25 degrees C. The results indicate that the reduction of Fe(III) by AA is of zero order with respect to AA. The reaction order with respect to Fe(III) cannot be represented by a simple kinetic model at pH 5 or 6. The major stage of the reduction (about 80%, stoichiometrically), however, could be represented by a general equation of -d[Fe(III)]/dt = k[Fe(III)],(1. 811) where k is a rate constant and [Fe(III)] is the total ferric concentration. The rate constant decreased 1 order of magnitude as pH increased from 5 to 6. Aging of Fe(III) solution slows its reduction rate at pH 6 but not at pH 5.     

Studies on Ancient Rice—Where Botanists, Agronomists, Archeologists, Linguists, and Ethnologists Meet

Taiwan’s aboriginal peoples are thought to be related to ancestral Austronesian-speaking peoples. Currently, Taiwan has 14 officially acknowledged aboriginal tribes. The major crops currently farmed in aboriginal areas are rice (Oryza sativa) and foxtail millet (Setaria italica). Archeologists recently excavated the remains of several early cultures in Taiwan. The most plentiful plant remains were carbonated rice and foxtail millet grains. The earliest ¹⁴C date of these excavation sites is ～5,000 bp. These settlements may be those of the earliest ancestral Austronesian speakers in Taiwan. Rice domestication is a complex story. In this study, we identified the functional nucleotide polymorphisms of 16 domestication-related genes using 60 landraces collected from aboriginal Taiwanese villages about 100 years ago. We also screened the phenotypes of these landraces. By integrating pheno- and genotypic data, together with data from archeologists and linguists, we may be able to better understand the history of rice cultivation in Taiwan and nearby areas.     

Effect of pH on the Analysis of 2-MIB and Geosmin in Water

2-Methylisoborneol (2-MIB) and trans-1,10-dimethyl-trans-9-decalol (geosmin) are two commonly observed taste and odor compounds present in drinking water sources. The effects of pH on the analysis of the two chemicals are investigated using a gas chromatograph and mass spectrometric detector (GC/MSD) coupled with three pre-concentration methods, namely solid-phase micro-extraction (SPME), purge-and-trap concentration (PTC), and liquid–liquid extraction (LLE). At neutral and alkaline pH conditions, the concentrations detected for both compounds remain constant. However, a substantial reduction of concentration for both chemicals is observed when the water solution pH is less than 5. Under acidic conditions (pH ≅ 2.5), the 2-MIB concentrations detected by GC/MSD coupled with SPME, PTC, and LLE are 87%, 16%, and 37% lower than those measured at pH 6–7, respectively. For geosmin, a decrease in concentration is only observed when using GC/MSD-SPME, presumably due to the higher extraction temperature compared to the other two techniques. The pH-dependent behavior was attributed to dehydration of the tertiary alcohols of 2-MIB and geosmin under acidic conditions. The dehydration for 2-MIB and geosmin is reversible, and the analysis can be mitigated by adjusting the water solution pH back to a neutral condition.     

In vivo screening of zebrafish microRNA responses to bacterial infection and their possible roles in regulating immune response genes after lipopolysaccharide stimulation

Micro (mi)RNAs are abundant small noncoding RNAs found in plants and animals, the regulatory functions of which are not fully understood in fish. To identify potential miRNAs, we screened an miRNA microarray with total RNA from zebrafish infected with Vibrio harveyi and another from uninfected zebrafish. Six miRNAs were obtained from the microarray screening. We studied miRNA expression patterns of 2 miRNAs (miR-122 and miR-194) after bacterial infection of transgenic zebrafish (containing tilapia hepcidin (TH)2-3) and non-transgenic zebrafish from which the 2 miRNAs were obtained from the microarray experiment. The results indicated that miR-122 and miR-194 were higher in PBS-injected zebrafish compared with TH2-3 zebrafish or wild-type (WT) zebrafish after V. harveyi infection. Overexpression of miRNAs (miR-122, miR-192, and miR-194a) was seen in zebrafish liver (ZFL) cells after lipopolysaccharide (LPS) treatment and in untreated fish. Our results showed that after 24?h of doxycycline treatment without LPS stimulation, interleukin (IL)-22, lysozyme, toll-like receptor (TLR)1, TLR3, TLR4a, and tumor necrosis factor (TNF)-α gene expressions were, respectively, upregulated by ~14-, 22-, 2.2-, 13-, 200-, and 38-fold in miR-122-transfected compared with non-transfected (WT) ZFL cells. In cells transfected with miR-192 and treated with LPS after 8-12?h, IL-22, lysozyme, TLR1, TLR3, TLR4a, and TNF-α expressions significantly differed between WT and miR-192-overexpressing ZFL cells. However, we observed significantly higher IL-22 expression levels after 12?h of LPS treatment in miR-192-transfected ZFL cells compared with non-transfected cells. In contrast, IL-22, lysozyme, and TNF-α were markedly upregulated (>100-fold) after miR-194a transfection and overexpression in ZFL cells and treatment with LPS. Our cloning and expression analyses indicated that miR-122, miR-192, and miR-194a play important roles in zebrafish immunology.     

Complex dynamics may limit prediction in marine fisheries

Complex nonlinear dynamics in marine fisheries create challenges for prediction and management, yet the extent to which they occur in fisheries is not well known. Using nonlinear forecasting models, we analysed over 200 time series of survey abundance and landings from two distinct ecosystems for patterns of dynamic complexity (dimensionality and nonlinear dynamics) and predictability. Differences in system dimensionality and nonlinear dynamics were associated with time series that reflected human intervention via fishing effort, implying the coupling between human and natural systems generated dynamics distinct from those detected in the natural resource subsystem alone. Estimated dimensionality was highest for landings and higher in abundance indices of unfished species than fished species. Fished species were more likely to display nonlinear dynamics than unfished species, and landings were significantly less predictable than abundance indices. Results were robust to variation in life history characteristics. Dynamics were predictable over a 1‐year time horizon in seventy percent of time series, but predictability declined exponentially over a 5‐year horizon. The ability to make predictions in fisheries systems is therefore extremely limited. To our knowledge, this is the first cross‐system comparative study, and the first at the scale of individual species, to analyse empirically the dynamic complexity observed in fisheries data and to quantify predictability broadly. We outline one application of short‐term forecasts to a precautionary approach to fisheries management that could improve how uncertainty and forecast error are incorporated into assessment through catch limit buffers.     

Effects of chemical and organic fertilizers on the growth,flower quality and nutrient uptake of Anthurium andreanum, cultivated for cut flower production

Sustainable agriculture has become a concern, due to the pressures of the “energy crisis” and issues of “environmental protection”. The use of organic fertilizer made from agricultural waste regenerates natural resources and reduces the consumption of fossil energy as well as phosphorus (P) and potassium (K) deposits. There is scant information available concerning the use of organic fertilizer as the sole source of nutrients in flower production, especially in the cultivation of flowers in a soilless condition. The objective of this study was to develop an organic fertilization management system to replace the chemical fertilization management of the cut flower production of Anthurium andreanum Lind. cultivated under soilless conditions. Four fertilization treatments were carried out consisting of two chemical fertilizers [controlled release fertilizer (CRF) and a chemical nutrient solution (CNS)], and two organic fertilizers [pea and rice hull compost (PRHC) and cattle dung with tea leaf residue compost (CDTC)]. The effects of the various fertilizations on A. andreanum were evaluated based on plant growth, nutrient uptake, and cut flower quality during the 1-year experimental period. The results show that the growth, yield, and cut flower quality of plants receiving PRHC were the same as those receiving CNS and CRF, indicating that PRHC can substitute for CRF and CNS as a nutrient source for cut flower production of A. andreanum cultivated in soilless condition. The plants that received the CNS and PRHC treatments had a significantly increased leaf number and new leaf growth area than those that received the CRF and CDTC treatments. The plants receiving the CDTC showed the lowest increase in leaf area and number of flowers. The retardant growth of plants treated with CDTC has been explained as being due to less carbon (C) being assimilated, most likely as the result of an insufficient supply of nitrogen (N) and manganese (Mn) toxicity. The petiole and peduncle length of the plants receiving the CRF were the shortest, which might be due to the low level of potassium (K) accompanying the magnesium (Mg) deficiency. Even though there were significant differences in the N and K concentrations of the plants among the different treatments, no significant differences were observed in the cut flower quality. In short, the organic fertilizer PRHC can meet the nutrient requirements of A. andreanum cultivation for the cut flower production under soilless conditions.     

小麦植株在麦田CH4交换中的作用及光照的影响

采用密闭箱/气相色谱法对中国科学院山东禹城实验站的麦田CH4通量进行观测,研究了土壤CH4通量、光照和遮光情况下的土壤-植物系统CH4通量,及植物、光照等因素对CH4通量的影响.试验采用小暗箱测定土壤CH4通量,采用暗箱和明箱测定土壤-植物系统CH4通量,同步观测了生物量、5 cm土壤温度、土壤水分及土壤NH4+含量.结果表明,麦田土壤和土壤-植物系统CH4通量均无明显的日变化,但季节变化显著;小麦的存在使土壤-植物系统CH4通量的季节波动加剧;小麦植株和光照促进麦田土壤-植物系统对CH4的吸收.此外,本研究发现在野外观测中,采用明箱覆盖土壤以及植物进行观测更能真实反映有植被覆盖的地表CH4通量状况.     

Polypropylene/high-density polyethylene/carbon fiber composites: Manufacturing techniques,mechanical properties,and electromagnetic interference shielding effectiveness

This study uses polypropylene (PP)/high-density polyethylene (HDPE) polyblends (80/20 wt.%) as matrices, which are then melt-blended with inorganic carbon fibers (CF) as reinforcement to form electrically conductive PP/HDPE composites. Tensile test, flexural test, Izod impact test, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) are performed to evaluate different physical properties of samples. A surface resistance and electromagnetic interference shielding effectiveness (EMI SE) measurements are used to evaluate the electrical properties of the PP/HDPE/CF composites. Test results show that an increasing content of carbon fibers results in an 18 %, 23 %, and 60 % higher tensile strength, flexural strength, and impact strength, respectively. SEM results show that carbon fibers break as a result of applied force, thereby bearing the force and increasing the mechanical properties of composites. DSC and XRD results show that the addition of carbon fibers causes heterogeneous nucleation in PP/HDPE polyblends, thereby increasing crystallization temperature. However, the crystalline structure of PP/HDPE composites is not affected. Surface resistivity results show that 5 wt.% of carbon fibers can form a conductive network in PP/HDPE polyblends and reduce the surface resistivity from 12×10¹² ohm/sq to 4×10³ ohm/sq. EMI SE results show that, with a 20 wt.% CF and a frequency of 2-3 GHz, the average EMI SE of PP/HDPE/CF composites is between -48 and -52 dB, qualifying their use for EMI SE, which is required for standard electronic devices.