Fluorescence properties of novel deep-red phosphor LiMg4SbO7:Mn4+ with excellent quantum efficiency and color purity for warm white LEDs.

Red fluorescent materials have important application value in the background light and LED lighting fields of displays. In this work, a novel type of rare earth free deep-red phosphor LiMg4SbO7:Mn4+ was prepared successfully, and its crystal structure, microstructure, fluorescence spectrum, quantum yield, thermal stability, fluorescence lifetime, color coordinates and color purity were studied in detail. The excitation spectra of LiMg4SbO7:Mn4+ phosphors are located at 200-600 nm, which can be matched with ultraviolet, near-ultraviolet, and blue-light chips. The exciting result is that the LiMg4SbO7:0.002Mn4+ phosphor exhibits astonishing quantum efficiency, thermal stability and color purity. Finally, the developed LiMg4SbO7:Mn4+ and the yellow phosphor Y3Al5O12:Ce3+ (YAG:Ce3+) were mixed and coated on a blue light chip (460 nm) to produce a w-LED, which exhibited warm white luminescence with color coordinates of (0.3575, 0.3809), correlated colour temperature (CCT) of 4687 K, and color rendering index (CRI) of 83.6. It is reasonable to consider that LiMg4SbO7:Mn4+ phosphors with excellent photoluminescence performance have great application value in LED lighting fields.

Separation, identification, and structural characterization of sucrose ester isomers from tobacco.

Sucrose esters (SEs) are crucial tobacco smoke flavor precursors and play a significant role in tobacco's functionality. Due to their structural complexity, the separation and analysis of SEs in tobacco remain a major challenge, and massive structures of SEs have not yet been fully identified. In this study, the fractions enriched in SEs were obtained from oriental and flue-cured tobacco through a series of pretreatments, and two types of SEs (Types I and II) were distinguished by liquid chromatography-tandem mass spectrometry (LC-MSn ) analysis, with Type II SEs newly characterized in tobacco. Five groups of main SEs were further purified using preparative high-performance LC (HPLC) coupled to an evaporative light scattering detector, and their structures were characterized by nuclear magnetic resonance spectrometry techniques including 1 H, 13 C, correlation spectroscopy, heteronuclear single quantum correlation, and heteronuclear multiple bond correlation. By combining LC-MSn and nuclear magnetic resonance spectrometry, the structures of eight SE isomers were finally proposed, of which four were newly identified. These findings further enhance the understanding of the structural diversity of SEs in tobacco, serving as a valuable reference for future research on the elucidation, synthesis, and metabolism of SEs.

A Leymus chinensis histidine-rich Ca2+-binding protein binds Ca2+/Zn2+ and suppresses abscisic acid signaling in Arabidopsis.

Intracellular Ca2+ plays an essential role in plant cellular sensing of various environmental stress signals by modulating the activity of Ca2+-binding proteins. Leymus chinensis is a dominant forage grass widely distributed in the Eurasian Steppe that is well adapted to drought and salty soils common in the region. Through transcript profiling of L. chinensis roots, we identified a transcript predicted to encode histidine-rich calcium-binding protein (HRC), a protein recently characterized in wheat. L. chinensis HRC (LcH RC) localized in the nucleus, as demonstrated using a transient gene expression method that we developed for this species. Different regions of LcHRC showed affinity for either Ca2+ or Zn2+, but not Mg2+ and Mn2+. Arabidopsis thaliana seedlings heterologously overexpressing LcHRC showed greater sensitivity to abscisic acid (ABA), along with decreased expression of some ABA-induced marker genes, but no increase in ABA content. Screening a Arabidopsis cDNA yeast library identified a Tudor/PWWP/MBT-domain-containing protein (AtPWWP3) that interacts with LcHRC. AtPWWP3 also localized in the nucleus and is predicted to mediate gene expression by modifying histone deacetylation. Based on these results, we propose a functional model of LcHRC action.

Extracellular Ca2+ induces desensitized cytosolic Ca2+ rise sensitive to phospholipase C inhibitor which suppresses root growth with Ca2+ dependence.

Calcium (Ca) is an essential element for all organisms. In animal cells, the plasma membrane-localized Ca receptor CaSR coupled to a phospholipase C (PLC)-dependent signaling cascade monitors extracellular Ca2+ concentrations ([Ca2+]ext) and responds with increases in cytosolic calcium concentrations ([Ca2+]cyt). Plant roots encounter variable soil conditions, but how they sense changes in [Ca2+]ext is largely unknown. In this study, we demonstrate that increasing [Ca2+]ext evokes a transient increase in [Ca2+] in the cytosol, mitochondria, and nuclei of Arabidopsis thaliana root cells. These increases were strongly desensitized to repeat applications of [Ca2+]ext, a typical feature of receptor-mediated cellular signaling in animal and plant cells. Treatment with gadolinium (Gd3+), a CaSR activator in animal cells, induced concentration-dependent increases in [Ca2+]cyt in roots, which showed self-desensitization and cross-desensitization to [Ca2+]ext-induced increases in [Ca2+]cyt (EICC). EICC was sensitive to extracellular H+, K+, Na+, and Mg2+ levels. Treatment with the PLC inhibitor neomycin suppressed EICC and Ca accumulation in roots. The inhibitory effect of neomycin on root elongation was fully rescued by increasing [Ca2+]ext but not [Mg2+] or [K+] in the growth medium. These results suggest that [Ca2+]ext and the movement of Ca2+ into the cytosol of plant roots are regulated by a receptor-mediated signaling pathway involving PLC.

Arabidopsis thaliana branching enzyme 1 is essential for amylopectin biosynthesis and cesium tolerance.

Arabidopsis thaliana BRANCHING ENZYME 1 (AtBE1) is a chloroplast-localized embryo-lethal gene previously identified in knockout mutants. AtBE1 is thought to function in carbohydrate metabolism; however, this has not been experimentally demonstrated. Chlorosis is a typical symptom of cesium (Cs) toxicity in plants. The genetic target of Cs toxicity is largely unknown. Here, we isolated a Cs+-tolerant and chlorophyll-defective Arabidopsis ethyl methanesulfonate (EMS) mutant, atbe1-5. Mapping by sequencing and genetic complementation confirmed that a single amino acid change (P749S) in a random coil motif of AtBE1 confers the mutant's Cs+-tolerant and chlorophyll-defective phenotype. An isothermal titration calorimetry assay determined that the 749th residue is the Cs+-binding site and hence likely the target of Cs+ toxicity. We hypothesized that binding of Cs+ to the 749th residue of AtBE1 inhibits the enzyme's activity and confers Cs+ toxicity, which in turn reduces photosynthetic efficiency. In support with this hypothesis, atbe1-5 leaves have a reduced photosynthetic efficiency, and their amylose and amylopectin contents are ∼60 % and ∼1%, respectively, of those in Col-0 ecotype leaves. Leaves of the mutant have a lower sucrose, but higher maltose, concentration than those of Col-0. This study demonstrated that AtBE1 is an essential gene for amylopectin and amylose biosynthesis, as well as the target of Cs+ toxicity; therefore, it can serve as a genetic locus for engineering plants to extract Cs+ from contaminated soil while maintaining growth.

[Regulatory effect of Bushenfang on the serum testosterone level of naturally aging rats and its mechanism].

OBJECTIVE: To study the regulatory effect of Bushenfang on the serum testosterone (T) level of naturally aging rats and its mechanism, in order to provide a theoretical and experimental basis for the clinical treatment of late onset hypogonadism (LOH) in males. METHODS: Thirty-two 18-month-old male SD rats were randomly divided into four groups of equal number, naturally aging model and low-, medium- and high-dose Bushenfang groups, and another eight 4-month-old rats were taken as normal controls. The rats of the aging model and normal control groups were treated with normal saline, while those of the low-, medium- and high-dose Bushenfang groups received intragastrically Bushenfang at 3.25, 7.50 and 15.00 g/kg, respectively, all for 3 weeks. Then the rats were sacrificed, the histomorphologic changes of the testis observed by HE staining, the serum T level measured by radioimmunoassay, and the expressions of the StAR protein, P450scc and 3beta-HSD I determined by RT-PCR. RESULTS: The number of Leydig cells was obviously increased after Bushenfang treatment. The levels of serum T were significantly higher in the low-, medium- and high-dose Bushenfang groups ([6.74 +/- 1.56] nmol/L, [8.50 +/- 1.99] nmol/L and [12.41 +/- 2.91] nmol/L) than in the model group ([3.48 +/- 0.75] nmol/L) (P < 0.05). The three Bushenfang groups also showed a remarkable elevation in the mRNA expressions of StAR (0.74 +/- 0.29, 0.83 +/- 0.32 and 1.35 +/- 0.50), P450scc (0.72 +/- 0.36, 1.023 +/- 0.30 and 1.41 +/- 0.37) and 3beta-HSD I (0.58 +/- 0.14, 0.72 +/- 0.07 and 0.85 +/- 0.18), as compared with the models (StAR: 0.44 +/- 0.09; P450scc: 0.33 +/- 0.05; 3beta-HSD I: 0.34 +/- 0.02), with significant differences in the StAR expression between the high-dose Bushenfang and the model groups, as well as in P450scc and 3beta-HSD I expressions between the medium- and high-dose Bushenfang and the model groups (P < 0.05). CONCLUSION: Bushenfang could improve the pathological status of testicular injury and increase the expression of testosterone synthetase, which might be the mechanism behind its regulatory effect on the serum T level of aging rats.

[Evaluation on the effects of education regarding road safety among middle school students].

OBJECTIVE: To evaluate the intervention effects for road traffic accident prevention among middle school students through understanding their knowledge, attitude and practice (KAP) on road safety. METHODS: Students in Grade 1 and Grade 2 from 7 junior and senior middle schools in Ji'nan city were selected as intervention group and students from a middle school in Hefei city served as control group. Education was provided to the intervention group and all the middle school students in Ji'nan city. Changes of KAP on road safety were measured for both groups during the follow-up period, and comparison on KAP for the two groups was carried statistically. RESULTS: The mean scores of road safety knowledge for intervention group improved significantly during the follow-up period (from 0.9 - 3.8), while these indices did not change much in the control group (from 0 - 0.2). Negative attitude on road safety was found in both groups, but less in the intervention group. More students started to admit that middle school students themselves should be responsible for most of the RTAs. Per week frequency of violating traffic rules did not improve, however during the follow-up period on both groups as still 75% to 80% of the students violating the traffic rules less than 2 times per week. Although three kinds and one kind of traffic rules violation seemed to have improved in the intervention group and in the control group, there were still two and three other kinds turned worse in the intervention and in the control group, respectively. CONCLUSION: Program on road safety education significantly improved the relative knowledge for middle school student and it exerted positive effects in road safety attitude to some extent. However, no significant effect was found in the improvement on their behavior. Education on road safety should be carried out in the early stage of childhood with newer and more effective intervention approaches.

The association between sleep and injury among school-aged children in rural China: a case-control study.

OBJECTIVE: To explore the association between sleep and accidental injury among school-aged children in a rural area of China. METHODS: Information was collected regarding parent-reported sleep patterns and problems of 182 children with a history of a medically attended injury in the previous 12 months and of 207 non-injured control children, and data were analyzed to compare differences between the two groups of children. RESULTS: Global sleep disturbance (Children's Sleep Habits Questionnaire [CSHQ] total score) was significantly higher in the injured group (IG) than in the non-injured group (NIG), and a greater percentage of the IG scored above the clinical cut-off score on the CSHQ. Stepwise multivariate logistic regression analysis showed that the CSHQ parasomnias and daytime sleepiness subscale scores were significantly and positively related to injury. Sleep duration was also shorter in the IG, and this group had a greater percentage (23% vs 12%) of "short sleepers" (<9h). In addition, a greater percentage of "short sleepers" (91% vs 27%) had more than two injuries. CONCLUSION: This study supports an association between injuries and sleep disturbances, including shorter sleep duration and daytime sleepiness, in Chinese children.

[Risk factors on road traffic accidents in middle school students: a matched case-control study].

OBJECTIVE: To investigate the predictors of road traffic accidents (RTAs) in middle school students, a case-control study was designed to seek new clues for prevention and control on RTAs in this population. METHODS: Cases were 116 students who experienced RTAs from 2005/01/01 to 2005/12/31. 116 students were served as controls who were from the same class of the cases and matched by age and sex. Information on personal behavior, family conditions, and knowledge, attitude, practice (KAB) on road traffic of these children were collected and compared. Conditional logistic regressions were conducted to analyze the relationship between these factors and RTAs. RESULTS: Compared to the controls, the cases showed more negative attitude and risk-taking-behaviors especially in riding bicycle. However, knowledge on road safety showed less significant differences between case and control groups. The negative attitude and risk-taking-behaviors were independent risk factors for RTAs by logistic regression. In addition, distance from home to school that longer than 1000 m seemed a risk factors for RTAs, while high education levels among mothers was a protective factor. CONCLUSION: Road safety attitude and behavior, distance from home to school were the main influence factors for RTAs among middle school students. It seemed more important in improving the attitude and behavior on road safety than to enhance the knowledge for prevention and control of RTAs among middle school students.

Expression of cholera toxin B subunit and assembly as functional oligomers in silkworm.

The nontoxic B subunit of cholera toxin (CTB) can significantly increase the ability of proteins to induce immunological tolerance after oral administration, when it was conjugated to various proteins. Recombinant CTB offers great potential for treatment of autoimmune disease. Here we firstly investigated the feasibility of silkworm baculovirus expression vector system for the cost-effective production of CTB under the control of a strong polyhedrin promoter. Higher expression was achieved via introducing the partial non-coding and coding sequences (ATAAAT and ATGCCGAAT) of polyhedrin to the 5' end of the native CTB gene, with the maximal accumulation being approximately 54.4 mg/L of hemolymph. The silkworm bioreactor produced this protein vaccine as the glycoslated pentameric form, which retained the GM1-ganglioside binding affinity and the native antigenicity of CTB. Further studies revealed that mixing with silkworm-derived CTB increases the tolerogenic potential of insulin. In the nonconjugated form, an insulin : CTB ratio of 100 : 1 was optimal for the prominent reduction in pancreatic islet inflammation. The data presented here demonstrate that the silkworm bioreactor is an ideal production and delivery system for an oral protein vaccine designed to develop immunological tolerance against autoimmune diabetes and CTB functions as an effective mucosal adjuvant for oral tolerance induction.