基于分形理论的红层软岩崩解性消除方法研究

东汉末年的荆州,兴起了具有与此前儒教不同特点的新儒教－荆州学。它的形成不仅缘于宋忠、綦毋闿等刘表集团的内部成员,同时也包括了司马徽、庞德公等在野的名士。在这样广泛的交友关系中成立的荆州学到底具有怎样的特征。又是为何诞生于荆州？修习了荆州学的诸葛亮在刘备处仕官,最终在蜀汉建国过程中起到了重大作用。荆州学又在诸葛亮的思想里占据了怎样的地位？此外,在经学上师承宋忠的王肃对汉代经学的集大成者郑玄进行了全面的否定和批判。荆州学是经过了怎样的演变才出现了王肃反郑的现象？     

Anticancer activities of thelephantin O and vialinin A isolated from Thelephora aurantiotincta

Thelephora aurantiotincta is an edible mushroom belonging to the genus Thelephora; it grows in symbiosis with pine trees. Recently, phytochemical investigations have revealed that the genus Thelephora is an abundant source of p-terphenyl derivatives. However, their bioactivity has not yet been well characterized. In screening for natural materials with anticancer activity, a T. aurantiotincta ethanol extract (TAE) was found to decrease cell viability in human hepatocellular carcinoma cells (HepG2). In this study, a new p-terphenyl derivative, thelephantin O, and a known compound, vialinin A, were isolated as the principal bioactive components of TAE. These compounds decreased cell viability in HepG2 and human colonic carcinoma cells (Caco2), but not in noncancerous human hepatocytes. This is the first report of the isolation from T. aurantiotincta of selective cytotoxic agents against cancer cells.     

Physicochemical properties of the soils associated with shifting cultivation in Northern Thailand with special reference to factors determining soil fertility

Abstract

Recently agricultural activity in the mountainous area of northern Thailand has increased and problems relating to soil fertility have arisen. In order to gain basic information about the soil properties associated with shifting cultivation, physicochemical properties of the surface soils (0–10 cm) and subsoils (30–40 cm) were investigated in selected villages in the area. The physicochemical properties of the soils studied are summarized as follows: 1) The soils were rich in organic matter, content of which ranged from 11.4 to 63.3 g C kg^?1 in the surface soil. 2) The pH(H₂O) of the soils mostly ranged from 5 to 7 and soil acidity was more pronounced in the deeper horizons. In the surface soils, exchangeable Ca and Mg were generally dominant, whereas exchangeable Al was often predominant in the subsoils. 3) Most of the soils showed a medium to fine texture with more than 30% clay. The clay mineral composition was characterized by various degrees of mixture of kaolin minerals and clay mica with, in some cases, a certain amount of 2:1-2:1:1 intergrades. 4) According to the ion adsorption curves, most of the B horizon soils were characterized by the predominance of permanent negative charges. On the other hand, organic matter contributed to the increase of variable negative charges in the surface soils. The content of organic matter and the percentage of the clay fraction were essential for determining the CEC of the soils of the surface 10 and 30–40 cm depths, respectively. Under the field conditions, the composition of exchangeable cations largely reflected the soil acidity. In addition, the content of organic matter also showed a significant correlation with that of available N in the surface soils. Thus, soil acidity both in the surface soils and subsoils, organic matter content in the surface soils, and clay content in the subsoils were considered to be the main factors that affected soil chemical fertility in the area.     

Ecological study on the dynamics of soil organic matter and its related properties in shifting cultivation systems of Northern Thailand

Abstract

There is a large number of hill people in northern Thailand, who practices shifting cultivation. In order to analyze the soil ecological problems involved in the transition from traditional shifting cultivation to more intensive upland farming, the authors carried out comparative studies on the dynamics of organic matter and its related properties in soils both in the traditional shifting cultivation systems adopted by Karen people and more intensive upland farming practiced by Thai and Hmong people in the area. The contents of organic matter and available N in the surface 10 cm layers of soil from the fields continuously cultivated were lower than those in soils under prolonged fallow (more than 10 y) or natural forest. Based on the rate of soil respiration, the amount of organic matter decomposed within 1 y was estimated to reach nearly 10% of that stored in the upper 50 cm layers of the soil profile in the upland crop fields. These results indicate that the organic matter-related resources markedly decreased under continuous cropping. The contents of C, N, and P in the microbial biomass of the surface 10 cm layers of soil ranged from 0.37 to 2.09 mg C g^?l soil, from 22.7 to 188 µg N g^?l soil, and from 6.1 to 65.7 µg P g^?l soil, respectively. Since the contents of microbial C, N, and P in the surface soils were generally higher under prolonged fallow and natural forests than in the fields continuously cultivated, the microbial activity and/or the amounts of C, N, and P available for biological activity seemed to have declined under continuous upland farming. The incubation experiment to assess the N mineralization pattern showed two remarkable characteristics: 1) there was an initial time lag until active mineralization of N occurred in the soils from young fallow forest and 2) the soil burning effect was observed after burning in the fields under prolonged fallow. The active process of nitrification after N mineralization was always associated with a sharp fall in soil pH, suggesting that soil acidification was promoted and basic cations were lost from the soils. In conclusion, rapid deterioration of the soil organic matter-related properties in cropping fields can be considered to be one of the ecological reasons why upland fields must be returned to fallow again a few years after forest reclamation in traditional shifting cultivation systems. Therefore, in alternative farming systems with more intensive land use, it is essential to apply organic materials into soils to decrease the rate of soil degradation, or to improve the soil fertility, in avoiding soil acidification along with nitrification.     

Host range and properties of <Emphasis Type="Italic">Tomato chlorotic dwarf viroid</Emphasis>

We characterised the host range and physical properties of Tomato chlorotic dwarf viroid. Among the 46 plant species inoculated with the viroid, two in the family Compositae and 23 in the family Solanaceae were found to be systemic hosts. The viroids in the crude sap from diseased tomato plants were thermally inactivated by heating to 100°C for at least 40 min. These viroids also lost their infectivity when diluted in phosphate buffer to at least 10⁻⁶, or after 3 days of incubation at room temperature. However, the infectivity of the viroids in dried crude sap from the plants persisted throughout the 50-day test period.     

Synthesis and herbicidal activity of optically active cinmethylin,its enantiomer,and C3-substituted cinmethylin analogs

We investigated the synthesis and herbicidal activity of optically active cinmethylin, its enantiomer, and C3-substituted cinmethylin analogs. Optically active cinmethylin could be obtained in seven steps with the Sharpless asymmetric dihydroxylation of α-terpinene. The synthesized cinmethylin and its enantiomer showed similar herbicidal activity, which was independent of the stereochemistry. Next, we synthesized cinmethylin analogs with various substituents at the C3 position. We found that analogs with methylene, oxime, ketone, or methyl groups at the C3 position show excellent herbicidal activity.     

Usefulness of computed tomography for cryptorchidism in bulls

Cryptorchidism is defined as the failure of the testis to descend into the scrotal position. Bulls with cryptorchidism have problems in both meat quality and husbandry management; thus, it is greatly important to accurately identify the retained testis and remove it during the early stage. Abdominal computed tomography (CT) was performed under general anesthesia in 34 bulls aged 3–9 months with cryptorchidism. All bulls underwent laparoscopic or incision approach for cryptorchidectomy, and 40 testes were dissected. The detection rates of retained testes were 64.5% in the abdominal cavity and 100% in the subcutaneous inguinal region, and the total detection rate was 72.5%. Furthermore, all cases in this study were suspected to have intra-abdominal cryptorchidism in primary care, but CT revealed that 22.5% of cases had cryptorchidism in the subcutaneous inguinal region. The CT value (mean ± standard deviation) of the retained testes was 20.96 ± 7.54 Hounsfield Unit, and the CT value and size of the retained testes showed a positive weak correlation with bovine age. Therefore, there is the demerit that general anesthesia and a huge device are necessary; nevertheless, CT is suggested to be useful in identifying the location of retained testes and selecting an appropriate surgical approach in bulls with cryptorchidism. Moreover, CT findings suggested that the maturation of the retained testes might depend not on the descending process but on age.     

Seasonality of serum levels of vitellogenin in male Japanese whiting, Sillago japonica, reared under natural temperature and photoperiod

ABSTRACT:   Because blood vitellogenin (Vg) has been considered a biomarker for environmental estrogens, the basal levels of Vg and 17β-estradiol (E₂) were determined in male Japanese whiting reared under natural conditions. Serum levels of Vg and E₂ were measured and gonadal development was assessed by gonadosomatic index (GSI) and histological observation in 8–10 male fish at monthly intervals throughout the annual reproductive cycle. Serum E₂ was <60 pg/mL throughout the study period. In contrast, serum Vg exhibited seasonal changes: serum levels of Vg gradually increased from April to May (mean 63 ± 13 ng/mL and 124 ± 48 ng/mL in April and May, respectively), and then reached a peak value (mean 352 ± 68 ng/mL) in June. Thereafter, serum Vg gradually decreased, reaching undetectable levels (<50 ng/mL) in October. Serum levels of Vg tended to increase in the male fish in which the GSI was >1%. Histological observation revealed that testes in such male fish were in active spermatogenesis and then all of the testes of male fish in which serum Vg decreased to ND levels were regressed. These results suggest that Vg productive potency (sensitivity to estrogens) may increase in the spermatogenic stage, resulting in production of Vg in response to very low levels of natural or xenobiotic estrogens.     

Differential expression of myostatin and its receptor in the porcine anterior pituitary gland

Myostatin (MSTN), known as growth and differentiation factor 8 (GDF-8), is a member of the transforming growth factor β (TGF-β) superfamily that negatively regulates skeletal muscle mass. Myostatin binds with high affinity to the receptor serine threonine kinase activin receptor type IIB (ActRIIB). Activins that also belong to the TGF-β superfamily, stimulate follicle-stimulating hormone production in gonadotrophs and suppress growth hormone and adrenocorticotropic hormone production in somatotrophs and corticotrophs, respectively. The aim of the present paper was therefore to clarify the endocrine action of MSTN in adenohypophysis. The present study details the expression and cellular localization of MSTN and ActRIIB in porcine anterior pituitary gland. The mRNA of MSTN and ActRIIB was consistently expressed in RT-PCR. Immunohistochemistry of MSTN and specific hormones showed that MSTN localized in thyrotrophs and gonadotrophs, in which most of the MSTN immunoreactive cells were identified as thyrotrophs. The immunostaining of ActRIIB was restricted to corticotrophs. These results indicate that MSTN was mainly produced in thyrotrophs and its receptor, ActRIIB, was restrictively contained in corticotrophs. Interestingly, thyrotrophs immunoreactive for MSTN were frequently close to corticotrophs immunoreactive for ActRIIB. The present study suggests that MSTN from thyrotrophs may regulate corticotroph function as a paracrine mediator among the porcine anterior pituitary cells.