v-myb avianmyeloblastosis viral oncogene homolog (MYB) transcription factors are key regulators of stress responsive gene expression in plants. In this study, the MYB gene, ChiMYB (GenBank accession ...No. KT948997), was isolated from Chrysanthemum indicum, and was functionally characterized with an emphasis on salinity stress tolerance. The full ChiMYB cDNA sequence (948 bp) encoded a typical R2R3 MYB transcription factor that contained 315 amino acid residues and two MYB domains. The temporal expression pattern of ChiMYB was noted in C. indicum, and the highest level was detected in the roots, followed by leaves and stems. ChiMYB expression was induced by NaCl treatments, and transient expression of the fusion of ChiMYB and green fluorescent protein (GFP) indicated that the protein was targeted to the nuclei of onion epidermal cells. Arabidopsis plants overexpressing ChiMYB displayed improved tolerance to drought and salt stress. When under salt stress conditions, transgenic Arabidopsis plants had higher survival rates than non-transgenic wild-type plants. Chlorophyll content, intercellular CO
concentration, photosynthetic rate, and stomatal conductance were higher in the transgenic Arabidopsis plants than in non-transgenic control plants. Further investigation revealed that ChiMYB was able to regulate the expression of RD29A, RAB18, COR15, ABI1, and ABA genes, which are involved in salt stress signaling pathways. Our findings demonstrated that ChiMYB is essential for plant responses to salt stress, and it may have great potential for the improvement of salt tolerance in crops.
Significant boron isotope fractionation occurs in nature (−70 ‰ to +75 ‰) due to the high geochemical reactivity of boron and the large relative mass difference between ¹⁰B and ¹¹B. Since the 1990s, ...reconstruction of ancient seawater pH using the isotopic composition of boron in bio-carbonates (δ ¹¹Bcₐᵣb), and then calculation of the past pCO₂ have become important issues for the international isotope geochemistry community, and are called the δ ¹¹B-pH proxy. Although many achievements have been made by this proxy, various aspects of boron systematics require rigorous evaluation. Based on the previous researches, mechanism of boron isotope fractionation, variation of boron isotope (δ ¹¹B) in nature (especially in bio-carbonates) and controlling factors of the δ ¹¹B-pH proxy, such as the dissociation constant of B(OH)₃ in seawater (pKₐ), the δ ¹¹B of seawater (δ ¹¹BSW), the boron isotopic fractionation factor between B(OH) ₄ ⁻ and B(OH)₃ (α ₄–₃), and the incorporated species of boron into bio-carbonates, are reviewed in detail and the research directions of this proxy are proposed. Generally, the controversy about pKₐ, δ ¹¹Bₛw, and α ₄–₃ is relatively less, but whether boron incorporated into bio-carbonates only in the form of B(OH) ₄ ⁻ remains doubtful. In the future, it is required that the physicochemical processes that control boron incorporation into carbonates be rigorously characterized and that the related chemical and isotopic fractionation be quantified. It is also necessary and important to establish a “best-fit empirically equation” between δ ¹¹Bcₐᵣb and pH of seawater based on the precipitation experiments of inorganic or culture experiments of corals or foraminifera. In addition, extended application of the δ ¹¹B-pH proxy to the earlier part of the Phanerozoic relying on the Brachiopods is worthy of studying. Like other geochemical indicators, there are limiting factors of δ ¹¹B; however, it remains a very powerful tool in the reconstruction of past seawater pH at present.
The hygrothermal aging of three-dimensional braided carbon fibre-epoxy resin composites prepared by vacuum assisted resin transfer moulding (VARTM) was investigated. Emphasis was given to the effect ...of external stresses, both tensile and compressive modes at stress levels of 10 and 20% ultimate tensile strength (UTS). Unstressed, tensile-stressed and compressive-stressed specimens were immersed in distilled water at 37
°C. Specimens were characterized by examining weight changes and evaluating variations of flexural and shear properties due to moisture ingress. It was concluded that the application of external stresses did not change the mechanism of moisture sorption. However, external stresses exerted apparent effects on moisture uptake, equilibrium moisture content and mechanical degradation. Moisture sorption was promoted and resisted, respectively under the actions of tensile and compressive stresses. The degree of mechanical deterioration of the composites depended on the level of moisture content. A mechanism which attributed the external stresses effects to changes of matrix strain, propagation of matrix cracks, and moisture transport at interfaces was proposed. Moreover, a comparison between the 3D and unidirectional composites was made to assess the influence of fibre structure.
Health care workers (HCWs) are at increased risk for tuberculosis (TB) infection. In China, surveys examining TB infection among HCWs have not studied general health care facilities, compared ...tuberculin tests conducted using local protocols against an internationally accepted test or characterised risk factors.
To measure the prevalence of and risk factors for TB infection among HCWs in Inner Mongolia, China.
Between April and August 2010, we administered QuantiFERON®-TB Gold In-Tube (QFT-GIT) tests, skin tests using Chinese tuberculin (TST) and surveys among HCWs at an infectious diseases hospital and a general medical hospital. We assessed whether demographic characteristics, personal exposure and work exposure were associated with QFT-GIT and TST positivity, and assessed agreement between test results.
Of 999 HCWs, 683 (68%) were QFT-GIT-positive, which was associated with greater age, longer HCW career, TB disease in a co-worker and greater daily patient exposure using multivariable analysis. TST reactions ≥ 5 mm occurred in 69% of the HCWs; agreement between test results was low ( 0.22).
The prevalence of TB infection among HCWs in Inner Mongolia is high; infection was associated with occupational exposure. Results from locally conducted TST are difficult to interpret. In China, TB infection control in health care facilities should be strengthened.
A Split Hopkinson pressure bar were used to experimentally study the dynamic behaviours of normal-strength concrete after exposure to elevated temperatures up to 700 °C. The dynamic strength and ...stress–strain relation curves of fire-damaged concrete were measured to unveil the effects of high temperature and strain rate on the dynamic behaviours of fire-damaged concrete. Test results showed that fire-damaged concrete still experienced remarkable strain rate effect and the dynamic stress versus strain relations of fire-damaged concrete were significantly different from those of concrete at room temperature. There was no obvious effect of temperature and strain rate on the shape of the ascending branches of normalized stress–strain relation curves of concrete after exposure to high temperatures. The tested results also showed that high temperature and strain rate had remarkable effect on the dynamic increase factor (DIF) for the fire-damaged concrete. The effect of high temperature on DIF of the fire-damaged concrete decreased as the temperature increased. The tested results can be a basis for assessing the impact resistance and anti-collapse resistance of fire-damaged concrete structures.
Supplementation of microbial phytase usually improves the digestibility and utilization of phosphorus in feedstuffs of plant origin. The effect of phytase supplementation on the digestibilities of AA ...also has been examined, but the results have been inconsistent. This study was carried out to determine the effect of phytase (Natuphos) supplementation, at a rate of 2,000 phytase units/kg, to two basal diets on the apparent ileal digestibilities (AID) of GE, CP, and AA, and on the apparent total-tract digestibilities (ATTD) of CP and GE. The basal diets contained 18% CP and were formulated (as-fed basis) to contain either a low (0.22%) or high content (0.48%) of phytate P. The high-phytate diet contained 20% rice bran, which is a rich source of phytate and has low intrinsic phytase activity. Eight barrows (average initial BW = 40.6 kg), fitted with a simple T-cannula at the distal ileum, were fed the four diets according to a replicated 4 x 4 Latin square design. The pigs were fed twice daily at 0800 and 2000, equal amounts each meal, at a rate of 2.4 times the daily maintenance requirement for ME. Each experimental period comprised 14 d. Ileal digesta were collected from 0800 to 2000 on d 12, 13, and 14. Feces were collected from 0800 on d 8 until 0800 on d 12. Chromic oxide was used as the digestibility marker. The AID of GE, CP, and AA and the ATTD of CP and GE were less in the high- than in the low-phytate diet (P < 0.01). With the exception of glutamic acid, phytase supplementation did not affect (P > 0.10) the AID of CP and AA. There was no effect (P > 0.05) of phytase on the ATTD of CP and GE. These results show that if a response occurs to phytase supplementation, it is independent of the dietary phytate content.
A new feature weighting method for band selection is presented, which is based on the pairwise separability criterion and matrix coefficients analysis. Through decorrelation of each class by ...principal component transformation, the criterion value of any band subset is the summations of the values of individual bands of it for the transformed feature space, and thus the computation amounts of calculating criteria of each band combinations are reduced. Following it, the corresponding matrix coefficients analysis is done to assign weights to original bands. As feature weighting considers little about the spectral correlation, the redundant bands are removed by choosing those with lower correlation coefficients than a preset threshold. Hyperspectral data classification experiments show the effectiveness of the new band selection method.
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