BOS1 is a basic helix-loop-helix transcription factor involved in regulating panicle development in rice.

Panicle development is crucial to increase the grain yield of rice (Oryza sativa). The molecular mechanisms of the control of panicle development in rice remain unclear. In this study, we identified a mutant with abnormal panicles, termed branch one seed 1-1 (bos1-1). The bos1-1 mutant showed pleiotropic defects in panicle development, such as the abortion of lateral spikelets and the decreased number of primary panicle branches and secondary panicle branches. A combined map-based cloning and MutMap approach was used to clone BOS1 gene. The bos1-1 mutation was located in chromosome 1. A T-to-A mutation in BOS1 was identified, which changed the codon from TAC to AAC, resulting in the amino acid change from tyrosine to asparagine. BOS1 gene encoded a grass-specific basic helix-loop-helix transcription factor, which is a novel allele of the previously cloned LAX PANICLE 1 (LAX1) gene. Spatial and temporal expression profile analyses showed that BOS1 was expressed in young panicles and was induced by phytohormones. BOS1 protein was mainly localized in the nucleus. The expression of panicle development-related genes, such as OsPIN2, OsPIN3, APO1, and FZP, was changed by bos1-1 mutation, suggesting that the genes may be the direct or indirect targets of BOS1 to regulate panicle development. The analysis of BOS1 genomic variation, haplotype, and haplotype network showed that BOS1 gene had several genomic variations and haplotypes. These results laid the foundation for us to further dissect the functions of BOS1.

LAZY1 Controls Tiller Angle and Shoot Gravitropism by Regulating the Expression of Auxin Transporters and Signaling Factors in Rice.

Tiller angle is a key factor determining rice plant architecture, planting density, light interception, photosynthetic efficiency, disease resistance and grain yield. However, the mechanisms underlying tiller angle control are far from clear. In this study, we identified a mutant, termed bta1-1, with an enlarged tiller angle throughout its life cycle. A detailed analysis reveals that BTA1 has multiple functions because tiller angle, shoot gravitropism and tolerance to drought stress are changed in bta1-1 plants. Moreover, BTA1 is a positive regulator of shoot gravitropism in rice. Shoot responses to gravistimulation are disrupted in bta1-1 under both light and dark conditions. Gene cloning reveals that bta1-1 is a novel mutant allele of LA1 renamed la1-SN. LA1 is able to rescue the tiller angle and shoot gravitropism defects observed in la1-SN. The nuclear localization signal of LA1 is disrupted by la1-SN, causing changes in its subcellular localization. LA1 is required to regulate the expression of auxin transporters and signaling factors that control shoot gravitropism and tiller angle. High-throughput mRNA sequencing is performed to elucidate the molecular and cellular functions of LA1. The results show that LA1 may be involved in the nucleosome and chromatin assembly, and protein-DNA interactions to control gene expression, shoot gravitropism and tiller angle. Our results provide new insight into the mechanisms whereby LA1 controls shoot gravitropism and tiller angle in rice.

Genome-wide identification and phylogenetic analysis of rice FTIP gene family.

FT-INTERACTING PROTEIN (FTIP) gene family in rice are the members of multiple C2 domain and transmembrane region proteins (MCTPs). There are many homologs of OsFTIPs in plants; however, the bioinformatics of them remains unclear. In the studies, 13 OsFTIP genes are identified in rice. OsFTIPs are unevenly located in 12 chromosomes. The OsFTIPs are phylogenetically divided into three clades. Cis-elements respond to abiotic stress, light, and hormones are found in the promoter region of OsFTIPs which are induced by the stimuli. All OsFTIPs are expressed with different profiles. Syntenic analysis of 128 OsFTIPs and FTIP-like homologs reveals that various number of gene pairs are identified between rice and other species. The 128 FTIP-like homologs are divided into six groups which fall into three classes. Ten motifs are shared by most OsFTIPs and their homologs. The studies provide a theoretical basis for further elucidating the functions of OsFTIP gene family.

Study about Mechanical Property and Machinability of Polyimide.

Polyimide (PI) is a kind of polymer material with properties of high heat-resistance and good mechanical strength. As a special engineering material, it has been widely used in the fields of aviation, nanotechnology, etc. PI has been regarded as one of the most promising engineering plastics in the future. Therefore, further research must be made on its mechanical properties and machinability of the PI, especially in ultra-precision machining. In this paper, both of the mechanical properties and machinability have been studied respectively. Through the nanoindentation experiment, the nanoindentation hardness and elastic modulus of PI are analyzed. Also, the single point diamond turning (SPDT) experiment is conducted to show that the form accuracy and surface roughness of PI surface can reach a submicron degree in peak-to-valley (PV) and a nanometer scale in surface roughness (Ra) respectively. The results demonstrate that the PI possesses good mechanical properties and machinability.

Quantification of Age-Related Tissue-Level Failure Strains of Rat Femoral Cortical Bones Using an Approach Combining Macrocompressive Test and Microfinite Element Analysis.

Bone mechanical properties vary with age; meanwhile, a close relationship exists among bone mechanical properties at different levels. Therefore, conducting multilevel analyses for bone structures with different ages are necessary to elucidate the effects of aging on bone mechanical properties at different levels. In this study, an approach that combined microfinite element (micro-FE) analysis and macrocompressive test was established to simulate the failure of male rat femoral cortical bone. Micro-FE analyses were primarily performed for rat cortical bones with different ages to simulate their failure processes under compressive load. Tissue-level failure strains in tension and compression of these cortical bones were then back-calculated by fitting the experimental stress-strain curves. Thus, tissue-level failure strains of rat femoral cortical bones with different ages were quantified. The tissue-level failure strain exhibited a biphasic behavior with age: in the period of skeletal maturity (1-7 months of age), the failure strain gradually increased; when the rat exceeded 7 months of age, the failure strain sharply decreased. In the period of skeletal maturity, both the macro- and tissue-levels mechanical properties showed a large promotion. In the period of skeletal aging (9-15 months of age), the tissue-level mechanical properties sharply deteriorated; however, the macromechanical properties only slightly deteriorated. The age-related changes in tissue-level failure strain were revealed through the analysis of male rat femoral cortical bones with different ages, which provided a theoretical basis to understand the relationship between rat cortical bone mechanical properties at macro- and tissue-levels and decrease of bone strength with age.

Effect of low-dose glucocorticoid on corticosteroid insufficient patients with acute exacerbation of chronic obstructive pulmonary disease.

BACKGROUND: This study aimed to investigate the prevalence rate of critical illness-related corticosteroid insufficiency (CIRCI) and the effect of low-dose glucocorticoid on prognosis of CIRCI in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: Since January 2010 to December 2012, 385 patients, who met the criteria of AECOPD, were enrolled in the Intensive Care Unit (ICU) of the First People's Hospital and Municipal Central Hospital of Xiangtan City. The AECOPD patients complicated with CIRCI screened by an adrenalcorticotrophic hormone test within 12 hours after admission to ICU were divided into a treatment group (n=32) and a control group (n=31) for a prospective, randomized and controlled clinical trial. Hydrocortisone (150 mg/d) or normal saline was injected intravenously for 7 days. The patients were followed up for 28 days after injection. The endpoint included 28-day survival time, non-shock time, ICU stay and the period of non-mechanical ventilation. The markers of inflammation C-reactive protein, tumor necrosis factor-α, interleukin 6 and procalcitonin were measured at baseline and 7 days after treatment. The variables were analyzed by Student's t test, the non-parametric statistical test, the Chi-square test or the Kaplan-Meier method with SPSS18.0 statistic software. A P value <0.05 was considered statistically significant. RESULTS: Totally 63 patients were diagnosed with CIRCI by an adrenalcorticotrophic hormone test and the prevalence rate was 16.4%. The shock rate of the AECOPD patients complicated with CIRCI was higher than that of the AECOPD patients without CIRCI (23.8% vs. 8.7%, P<0.01). Kaplan-Meier analysis revealed that the 28-day survival time of the treatment group was obviously longer than that of the control group (P<0.05). Compared with the control group, shock-free days within 28 days was longer in the treatment group (18.2±9.5 vs. 25.8±4.1, P<0.05). Treatment with low-dose glucocorticoid obviously decreased the markers of infection and inflammation (P<0.01), such as C-reactive protein (13.2±5.5 mg/L vs. 8.3±3.1 mg/L for the control group; 13.5±5.9 mg/L vs. 5.1±2.3 mg/L for the treatment group), tumor necrosis factor-α (26.1±16.2 µg/L vs. 17.5±11.7 µg/L for the control group; 25.0±14.8 µg/L vs. 10.4±7.8 µg/L for the treatment group) and procalcitonin (3.88 µg/L vs. 2.03 µg/L for the control group; 3.77 µg/L vs. 1.26 µg/L for the treatment group). Furthermore, the markers in the treatment group decreased more obviously than those in the control group (P<0.01). CONCLUSION: The prevalence rate of CIRCI was higher in the patients with AECOPD in the department of critical medicine, and low-dose glucocorticoid treatment for one week reduced the 28-day mortality, shock time and markers of infection and inflammation.

Cutting force predication based on integration of symmetric fuzzy number and finite element method.

In the process of turning, pointing at the uncertain phenomenon of cutting which is caused by the disturbance of random factors, for determining the uncertain scope of cutting force, the integrated symmetric fuzzy number and the finite element method (FEM) are used in the prediction of cutting force. The method used symmetric fuzzy number to establish fuzzy function between cutting force and three factors and obtained the uncertain interval of cutting force by linear programming. At the same time, the change curve of cutting force with time was directly simulated by using thermal-mechanical coupling FEM; also the nonuniform stress field and temperature distribution of workpiece, tool, and chip under the action of thermal-mechanical coupling were simulated. The experimental result shows that the method is effective for the uncertain prediction of cutting force.