Repetitiveness of languages generated by morphisms

We study the repetition of subwords in languages generated by morphisms. Fundamental to our approach is the notion of quasi-repetitive elements. Using these elements we present a new characterization for repetitive morphisms, from which we derive a simple proof for the fact that a D0L-language is repetitive if and only if it is strongly repetitive (Ehrenfeucht and Rozenberg, Inform. and Control 59 (1983) 13–35). From this proof we obtain a structurally simple polynomial-time algorithm for deciding whether such a language is repetitive. From further results on quasi-repetitive elements we obtain as a consequence a complete characterization for all those morphisms on a two-letter alphabet that are repetitive, a result which is closely related to a result of Séébold (Bull. EATCS 36 (1988) 137–151) on the D0L periodicity problem. Finally, we characterize those morphisms f on a two-letter alphabet, for which the language L(f) generated by f or the language SL(f) of subwords of L(f) are context-free or even regular.     

Continuous measurements of bronchial exposure induced by radon decay products during inhalation

The deposition of radon decay products is not equal in each of the respiratory regions and as the presence of radon has been linked with an increase in lung cancer risk, it is important to calculate the deposition of radon decay products in each of the respiratory regions. Recently, many studies on the deposition of radon in respiratory regions have been simulated using wire screens. The systems and equipment used in those studies are not suitable for field measurements as their dimensions are relatively massive, nor can they measure continuously. We developed a continuous bronchial dosimeter (CBD) which is suitable for field measurements. It was designed with specifications that allow it to be remain compact. The CBD simulates the deposition of radon decay products in the different respiratory regions by the use of a combination of wire screens. Deposition in the simulated regions of the lung can be continuously estimated in various environments. The ratio of activities deposited in a simulated nasal cavity (N) and tracheobronchial (TB) regions was calculated from the results of simultaneous measurements using CBD-R (reference), CBD-N (nasal), and CBD-TB (tracheobronchial) measurement units. After aerosols were injected into the radon chamber, the ratio of N and TB depositions decreased. This results indicate that the CBD gave a good response to changes in the environment. It was found that the ratio of N and TB deposition also varied with time in each actual environment.     

渤中凹陷古近系优质烃源岩特征及分布

综合应用钻井、地震等地质资料,以大量烃源岩样品地球化学分析为基础,从有机质丰度、类型、成熟度、沉积环境、母质来源以及生物标志物等方面对渤中凹陷古近系烃源岩地球化学特征进行了研究,指出了渤中凹陷优质烃源岩的发育层段,阐明了优质烃源岩的形成条件和分布规律,并在此基础上剖析优质烃源岩与油气成藏的关系,进一步揭示了渤中凹陷的勘探潜力。研究结果表明,渤中凹陷沙三段、沙二段—沙一段以及东营组3套烃源岩中都存在有机质丰度高、类型好、生排烃潜力大的优质烃源岩。其中,沙三段烃源岩有机质类型以Ⅰ型和Ⅱ1型为主,有机质丰度最高且已经进入生烃门限,优质烃源岩最为发育。从母质来源和沉积环境方面分析了3套烃源岩的形成条件,发现生物产率高、母源类型好、保存条件良好是优质烃源岩形成的主要原因。总结了优质烃源岩的时空展布特征,优质烃源岩的形成受控于沉积环境和沉积中心,主要发育于半深湖—深湖相带,由沉积中心向外逐渐变薄;优质烃源岩的空间分布控制了渤中凹陷油气分布,凹陷近源斜坡带是进一步油气勘探的有利地区。     

Evaluation of the lubrication mechanism at various rotation speeds and granule filling levels in a container mixer using a thermal effusivity sensor

To research the detailed mechanism of the lubrication process using the thermal effusivity sensor, the relationships of the lubrication progress with the pattern of powder flow, the rotation speed and the filling level were investigated. The thermal effusivity profile was studied as a function of the number of rotations at various rotation speeds. It was observed that at lower rotation speeds, the profiles of the lubrication progress were almost the same, regardless of the rotation speed. In this region, the highest speed was defined as the critical rotation speed (CRS), which was found to be one of the important factors. The CRS had close relations with avalanche flow in the blender. The first and the second phases were observed in the lubrication process. The first phase was influenced by the CRS and the filling level in the blender. The second phase was influenced by the rotation speed. The mechanism of two-phase process was proposed as a macro progression of the dispersion of the lubricant (first phase) and micro progression of the coating of the powder particles with lubricant (second phase). The accurate monitoring by the thermal effusivity sensor was able to help a better understanding in the lubrication process.     

Investigation on the Hydrogen Abstraction from Methyl Glucoside by Active Oxygen Species Under Oxygen Delignification Conditions. Part 5: Comprehensive Results on Experiments Using Deuterium-Labeled Methyl Glucosides

A pair of carbohydrate model compounds, methyl β-d-glucopyranoside (MGP) and a deuterated MGP labeled at each C-H bond, was reacted with active oxygen species (AOS) generated from reactions between O₂ and a co-existing phenolic compound, 2,4,6-trimethylphenol (TMPh) or 4-hydroxy-3-methoxybenzyl alcohol (vanillyl alcohol, Valc), under O₂ delignification conditions. The pair were also reacted with O? generated in the alkaline H₂O₂ treatment with the addition of FeCl₃. Clear kinetic isotope effects were observed only in the reactions of two pairs using the deuterated MGPs labeled at the anomeric and C-2 positions in this system. These results suggest that at least a specific AOS is generated only in this system and that a major AOS in the O₂-Valc system is highly reactive O?. It is also suggested that the AOS specifically generated only in this system is a peroxyl radical derived by the combination reaction between the TMPh phenoxyl radical and O₂.     

Development of a High-Affinity Antibody-Binding Peptide for Site-Specific Modification

Immunoglobulin G (IgG)-binding peptides such as 15-IgBP are convenient tools for the site-specific modification of antibodies and the preparation of homogeneous antibody–drug conjugates. A peptide such as 15-IgBP can be selectively crosslinked to the fragment crystallizable region of human IgG in an affinity-dependent manner via the ϵ-amino group of Lys8. Previously, we found that the peptide 15-Lys8Leu has a high affinity (K_d=8.19 nM) due to the presence of the γ-dimethyl group in Leu8. The primary amino group required for the crosslinking to the antibodies has, however, been lost. Here, we report the design and synthesis of a novel unnatural amino acid, 4-(2-aminoethylcarbamoyl)leucine (Aecl), which possesses both the γ-dimethyl fragment and a primary amino group. A peptide containing Aecl8 (15-Lys8Aecl) was synthesized and showed a binding affinity ten times higher (K_d=24.3 nM) than that of 15-IgBP (K_d=267 nM). Fluorescein isothiocyanate (FITC)-labeled 15-Lys8Aecl with an N-hydroxy succinimide ester at the side chain of Aecl8 (FITC-15-Lys8Aecl(OSu)) successfully labeled an antibody (trastuzumab, Herceptin^®) with the fluorophore. This peptide scaffold has both strong binding affinity and crosslinking capability, and could be a useful tool for the selective chemical modification of antibodies with molecules of interest such as drugs.     

Purification and characterization of a cold-active protease from psychrotrophic Serratia marcescens AP3801

Protease activity was detected in the culture medium of Serratia marcescens AP3801 grown at 10°C, which was isolated from soil collected from the top of a mountain. The enzyme, designated as CP-58 protease, was purified to homogeneity from the culture broth by ion exchange and gel filtration chromatographies. The molecular mass of the protease was 58 kDa, and its isoelectric point was close to 6.0. Maximal activity toward azocasein was observed at 40°C and from pH 6.5 to 8.0. The activity was strongly inhibited by 1,10-phenanthroline, suggesting that the enzyme is a metalloprotease. The N-terminal amino acid sequence was Ser-Leu-Asn-Gly-Lys-Thr-Asn-Gly-Trp-Asp-Ser-Val-Asn-Asp-Leu-Leu-Asn-Tyr-His-Asn-Arg-Gly-Asn (or Asp)-Gly-Thr-Ile-Asn-Asn-Lys-Pro-Ser-Phe-Asp-Ile-Ala. A search through databases for sequence homology aligned CP-58 protease with metalloprotease. The result of the cleavage pattern of oxidized insulin B-chain suggests that CP-58 protease has a broader specificity than other proteases against the peptide substrate.     

Confirmation of sulfur tolerance of bimetallic Pd–Pt supported on highly acidic USY zeolite by EXAFS

The sulfur tolerance (i.e., degree of sulfidation) of Pd and Pt in sulfided bimetallic Pd–Pt catalysts (Pd : Pt mole ratio of 4 : 1) supported on USY (ultrastable Y) zeolites (SiO₂/Al₂O₃ = 10.7, 48, and 310) was investigated using an extended X‐ray absorption fine structure (EXAFS) method. The sulfidation of the catalysts was done in a 1000 ppm H₂S–2% H₂/N₂ stream at 573 K for 0.5 h. In the Fourier transforms of Pd K‐edge and Pt L_III‐edge EXAFS spectra, both of the peaks due to metallic Pd and to metallic Pt for the Pd–Pt/USY (SiO₂/Al₂O₃ = 10.7) catalyst remained most after sulfidation. Further, the results of the Fourier transforms confirmed that the sulfur tolerance of both Pd and Pt decreased with increasing SiO₂/Al₂O₃ ratio, suggesting that Pd and Pt become sulfur‐tolerant when Pd–Pt bimetallic particles are supported on highly acidic USY zeolite. This revised version was published online in July 2006 with corrections to the Cover Date.     

Clinicopathological Significance of Loss of ARID1A Immunoreactivity in Ovarian Clear Cell Carcinoma

Recent genome-wide analysis has demonstrated that somatic mutations in ARID1A (BAF250) are the most common molecular genetic changes in ovarian clear cell carcinoma (OCCC). ARID1A mutations, which occur in approximately half of OCCC cases, lead to deletion of the encoded protein and inactivation of the putative tumor suppressor. In this study, we determined the significance of loss of ARID1A immunoreactivity with respect to several clinicopathological features in a total of 149 OCCCs. First, we demonstrated that ARID1A immunohistochemistry showed concordance with the mutational status in 91% of cases with 100% sensitivity and 66% specificity. Specifically, among 12 OCCC cases for which ARIDA mutational status was known, ARIDIA immunoreactivity was undetectable in all 9 cases harboring ARID1A mutations and was undetectable in one of 3 cases with wild-type ARID1A. With respect to the entire cohort, ARID1A immunoreactivity was undetectable in 88 (59%) of 149 OCCCs. There was no significant difference between ARID1A negative and positive cases in terms of histopathologic features, age, clinical stage, or overall survival. In conclusion, this study provides further evidence that mutations in ARID1A resulted in loss of ARID1A protein expression in OCCC, although no significant differences between ARID1A positive and negative cases were observed with respect to any clinicopathological features examined.     

冰提苜蓿冰结构蛋白及其对冷冻面团的影响

以紫花苜蓿草粉为原料,采用冰结合磷酸盐缓冲溶液法提取苜蓿冰结构蛋白。通过对苜蓿冰结构蛋白提取率的计算,对提取过程中的p H值、缓冲溶液的浓度、料液质量体积比进行优化。经单因素实验及响应曲面实验得到提取苜蓿冰洁构蛋白的最佳工艺参数为:料液质量体积比为1 g∶20 m L,缓冲液p H 8.0,磷酸盐缓冲液浓度为61 mmol/L,其最终提取率可达到2.87%。利用生物显微镜对苜蓿冰结构蛋白的冰晶形态进行观察,可以观测到许多体积小、且呈现六棱型及多边型的不规则形状,说明其对冰晶生长及冰晶形态的抑制与修饰效果显著,具有很好的抗冻活性。利用SDS-PAGE对苜蓿冰洁构蛋白进行检测,确定其蛋白质相对分子质量约为52 000,苜蓿冰结构蛋白应用到冷冻面团中发现可改善面团的品质。