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The effective pressure law for the intrinsic formation factor of low permeability sandstones from the Ordos Basin (northwest of China) was studied experimentally by measuring the electrical resistivity of brine saturated rock samples while cycling the pore and confining pressures, ppand pc. We used a 100,000 ppm NaCl solution so that the results could be directly interpreted in terms of the intrinsic formation factor F. The Response Surface method was used to construct a quadratic function of ppand pcfitting the experimental data, from which the coefficient αof the effective pressure law, peff= pc– αpp, was determined. We found that the coefficient αgenerally had low values, mainly from 0.2 to 0.4, thus contradicting the theoretical prediction that α should be equal to 1 for scale‐invariant properties, such as F, in linear elastic materials having a homogeneous solid matrix. Since the two underlying assumptions, linear elasticity and homogeneity of the solid matrix, are likely violated in reservoir rocks, we tried to assess their effects on α using simple analytical models, based on idealized geometries of the pore and solid phases. Analysis of these models suggests that non‐linear elasticity associated with the formation of solid–solid contacts in the compressed rocks (e.g., during closure of rough cracks or crack‐like pores along the grain boundaries), may be more effective in producing the low α values observed than inhomogeneity of the solid matrix. The intrinsic formation factor F of brine‐saturated low permeability sandstones were measured by cycling pore and confining pressuresEPL coefficient α mainly varies from 0.2 to 0.4 and contradicting the theoretical prediction of α = 1 for scale‐invariant propertiesNon‐linear elasticity associated with the formation of solid–solid contacts was considered the main reason for low α values

The origin of cancers is associated with etiology as well as therapeutics. Several studies reveal that malignancies in children can originate in utero. However, a diagnostic approach to distinguish between cancers initiated pre- or postnatally is absent. Here we identified a transcriptional factor FEV (fifth Ewing variant) that was expressed in fetal hematopoietic cells and became silent after birth. We characterized that FEV was essential for the self-renewal of hematopoietic stem cells (HSCs). We next found that FEV was expressed in most infant leukemia samples, but seldom in adult samples, in accord with the known prenatal origins of the former. We further determined the majority of pediatric acute lymphoid leukemia (ALL) and acute myeloid leukemia (AML) were FEV positive. Moreover, FEV knockdown markedly impaired the leukemia-propagating ability of leukemic stem cells. We therefore identified FEV is unique to fetal HSCs and stably expressed in leukemic cells of prenatal origin. It may also provide a tractable therapeutic target.

Chromosome segment substitution lines (CSSLs) are powerful tools to combine naturally occurring genetic variants with favorable alleles in the same genetic backgrounds of elite cultivars. An elite CSSL Z322-1-10 was identified from advanced backcrosses between a japonicacultivar Nipponbare and an elite indicarestorer Xihui 18 by SSR marker-assisted selection (MAS). The Z322-1-10 line carries five substitution segments distributed on chromosomes 1, 2, 5, 6 and 10 with an average length of 4.80 Mb. Spikilets per panicle, 1000-grain weight, grain length in the Z322-1-10 line are significantly higher than those in Nipponbare. Quantitative trait loci (QTLs) were identified and mapped for nine agronomic traits in an F3population derived from the cross between Nipponbareand Z322-1-10 using the restricted maximum likelihood (REML) method in the HPMIXED procedure of SAS. We detected 13 QTLs whose effect ranging from 2.45% to 44.17% in terms of phenotypic variance explained. Of the 13 loci detected, three are major QTL (qGL1, qGW5-1and qRLW5-1) and they explain 34.68%, 44.17% and 33.05% of the phenotypic variance. The qGL1locus controls grain length with a typical Mendelian dominance inheritance of 3:1 ratio for long grain to short grain. The already cloned QTL qGW5-1is linked with a minor QTL for grain width qGW5-2(13.01%) in the same substitution segment. Similarly, the previously reported qRLW5-1is also linked with a minor QTL qRLW5-2. Not only the study is important for fine mapping and cloning of the gene qGL1, but also has a great potential for molecular breeding.

ABSTRACTThe effect of post-harvest application of methyl jasmonate (MeJ) on reactive oxygen species, antioxidant systems, and cellular structure in Chinese winter jujube (Ziziphus JujubaMill.) at the major ripening stages of green maturity (GM) and half-red maturity (HM) were investigated. Jujube fruit at each ripening stage were treated with 0, 50, 100, and 200 μmol l−1MeJ for 24 h, then stored at 20 ± 2°C for shelf-life testing. Thereafter, changes in firmness, color, respiration rate, superoxide anion (O2−), hydrogen peroxide (H2O2), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), ascorbic acid (AsA), and glutathione (GSH) were measured at 4-d intervals for up to 8 d. Results showed that, in comparison with control fruit, MeJ treatment effectively suppressed the decrease of firmness, color, and respiration rate, inhibited the production of O2−and accumulation of H2O2and MDA, maintained higher activities of SOD and CAT and contents of AsA and GSH, and preserved the integrity of cell membranes and organelles. The degree of maturity influenced the benefits of MeJ application. The 100 μmol l−1MeJ treatment had a positive impact on antioxidant systems for GM fruit, whereas a MeJ concentration below 100 μmol l−1was found to extend the shelf life of HM fruit.

The electrical conductivity of brine‐saturated rock is predominantly dependent on the geometry and topology of the pore space. When a resistive second phase (e.g., air in the vadose zone and oil/gas in hydrocarbon reservoirs) displaces the brine, the geometry and topology of the pore space occupied by the electrically conductive phase are changed. We investigated the effect of these changes on the electrical conductivity of rock partially saturated with brine. We simulated drainage and imbibition as invasion and bond percolation processes, respectively, in pipe networks assumed to be perfectly water‐wet. The simulations included the formation of a water film in the pipes invaded by the nonwetting fluid. During simulated drainage/imbibition, we measured the changes in resistivity index as well as a number of relevant microstructural parameters describing the portion of the pore space saturated with water. Except Euler topological number, all quantities considered here showed a significant level of “universality,” i.e., insensitivity to the type of lattice used (simple cubic, body‐centered cubic, or face‐centered cubic). Hence, the coordination number of the pore network appears to be a more effective measure of connectivity than Euler number. In general, the simulated resistivity index did not obey Archie's simple power law. In log‐log scale, the resistivity index curves displayed a substantial downward or upward curvature depending on the presence or absence of a water film. Our network simulations compared relatively well with experimental data sets, which were obtained using experimental conditions and procedures consistent with the simulations. Finally, we verified that the connectivity/heterogeneity model proposed by Bernabé et al. (2011) could be extended to the partial brine saturation case when water films were not present. Simulations of drainage/imbibition in water‐wet pipe networksApproximately universal of the sense percolation theory in network simulationsResistivity index did not generally obey Archie's simple power law

The organic Rankine cycle low temperature waste heat power generation technology can be applied in water quenching blast furnace slag. To select a suitable fluid and improve the effectiveness of the process, 10 different working fluids were selected based on their characteristics (refrigerant, alkyl hydrogen, siloxane, etc.) and their application range in the co-generation project. Each co-generation system using the selected fluids was calculated by Matlab simulation programming. The results show that, in the case of constant evaporation and condensation temperatures, the thermal efficiency of the system increases, but the pressure decreases, with the rise in fluid critical temperature. Based on the comprehensive analysis of thermal efficiency, irreversible loss, unit mass flow power generation capacity, pressure level and environmental effect of the system, fluid R245fa, which is a hydrocarbon fluorine group type, is the best choice from the fluids tested.

Mesenchymal stem cells (MSC) play a crucial role in endothelial repair after artery injury. The high mobility group box 1 (HMGB1) is a key modulator of the homing of MSC to impaired artery and endothelialization. This study was aimed to determine whether balloon-induced carotid artery injury could be improved by transplantation with MSC modified by HMGB1. MSC were infected by adenoviral serotype 5 encoding recombinant green fluorescent protein (GFP) gene and HMGB1 (ad5GFP-HMGB1). The expression of HMGB1, vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) was detected in MSC using Real-time PCR, Western blot and semi-quantitative immunohistochemical assays. In vivo, reendothelialization was examined in rats subjected to carotid artery injury. The homing of MSC was observed under fluorescence microscopy, and the levels of serum tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) was assessed by ELISA assay. As a result, compared with the MSC group, the expression of HMGB1, VEGF and PCNA was markedly increased, vascular reendothelialization was accelerated, and the levels of serum TNF-α and CRP were decreased in group ad5GFP and ad5GFP-HMGB1. Transplantation of MSC infected with adGFP-HMGB1 strengthened the MSC effect. Taken together, modification of HMGB1 can enhance the protective effects of MSC on balloon-induced carotid artery injury through up-regulation of VEGF and PCNA expression and inhibition of the inflammatory response. HMGB1 in MSC may represent a novel therapeutic target for the treatment of endothelial repair.

The Columbia root‐knot nematode (Meloidogyne chitwoodiGolden et al.) is a serious pest that reduces tuber quality of potato (Solanum tuberosumL.) in the U.S. Northwest and other parts of the world. A gene, RMc1(blb), derived from the Mexican wild species Solanum bulbocastanumDunal, encodes resistance to this pest. An F1mapping population with >250 individuals generated from an intraspecific cross between resistant and susceptible clones of S. bulbocastanum,SB22 and PT29, respectively, was used for marker screening and genetic linkage analysis. One amplified fragment length polymorphism marker and five sequence tagged site (STS) markers cosegregated with RMc1(blb)The five STS markers were developed from bacterial artificial chromosome (BAC) end sequences of BAC clones that were derived from another wild species, S. demissumLindl, and contained homologs of resistance gene Nagainst tobacco mosaic virus. These markers were tested on families that were part of the introgression of RMc1(blb)into advanced breeding lines in BC5The utility of an efficient alternative to greenhouse and field phenotypic screening was demonstrated. The results of this study confirm that molecular markers closely linked to RMc1(blb)will assist in a selection program, reducing expense and time involved in root‐knot nematode screening.

Microsatellite or simple sequence repeat (SSR) markers were developed from Rosa wichurana Crépin to combine two previously constructed tetraploid rose (Rosa hybrida L.) genetic maps. To isolate SSR-containing sequences from rose a small-insert genomic library was constructed from diploid Rosa wichurana and screened with several SSR probes. Specific primers were designed for 43 unique SSR regions, of which 30 primer pairs gave rise to clear PCR products. Seventeen SSR primer pairs (57%) produced polymorphism in the tetraploid rose 90-69 mapping family. These markers were incorporated into existing maps of the parents 86-7 and 82-1134, which were constructed primarily with AFLP markers. The current map of the male parent, amphidiploid 86-7, consists of 286 markers assigned to 14 linkage groups and covering 770 cm. The map of the female tetraploid parent, 82-1134, consists of 256 markers assigned to 20 linkage groups and covering 920 cm. Nineteen rose SSR loci were mapped on the 86-7 map and 11 on the 82-1134 map. Several homeologous linkage groups within maps were identified based on SSR markers. In addition, some of the SSR markers provided anchoring points between the two parental maps. SSR markers were also useful for joining small linkage groups. Based on shared SSR markers, consensus orders for four rose linkage groups between parental maps were generated. Microsatellite markers developed in this study will provide valuable tools for many aspects of rose research including future consolidation of diploid and tetraploid rose genetic linkage maps, genetic, phylogenetic and population analyses, cultivar identification, and marker-assisted selection. [ABSTRACT FROM AUTHOR]

West-central China is an important endemic focus of both alveolar and cystic echinococcosis where several species of intermediate host are commonly infected with Echinococcus granulosus and E. multilocularis. Isolates of E. granulosus were collected from humans and other animals from different geographical areas of Qinghai, Ningxia, Gansu and Sichuan, and genotyped using the mitochondrial DNA marker ATP synthase subunit 6 gene (atp6). The sheep strain (G1 genotype) of E. granulosus was shown to be the only genotype present in sheep, cattle, goats, yaks and humans in the study areas. However, some heterogeneity in the atp6 sequence was evident in a number of the isolates with the most frequent change being a silent substitution (G/A) at position 360 compared with the G1 reference sequence representing isolates collected from the majority of hosts except humans. Two E. multilocularis isolates examined also had sequences that varied from each other and from the reference E. multilocularis atp6 sequence. The genotypic variation we report may reflect phenotypic differences with important consequences in terms of increased host infectivity for hosts by local Echinococcus strains, possibly impacting on the epidemiology and control of echinococcosis. Such adaptations may also result in different sensitivity to drugs or increased virulence for hosts that will impede control efforts and even affect vaccination strategies against Echinococcus.

Several iminosugar derivatives were synthesized, and their effects on the secretion of IL-4 and IFN-γ from the mouse splenocytes were examined. The effects on membrane expression of other T cell-associated molecules (CD3, CD4, CD8) and B cell-associated molecules (CD19) were also investigated. The experimental data demonstrated that synthetic iminosugars hold potential as immunosuppressive agents.

Keto-substituted hydrocarbons with 11−19 methylene and bis-terminal hydroxyl and carboxyl groups have been synthesized and evaluated in both in vivo and in vitro assays for their potential to favorably alter lipid disorders including metabolic syndrome. Compounds were assessed for their effects on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes as well as for their effects on lipid and glycemic variables in obese female Zucker fatty rats [Crl:(ZUC)-faBR] following 1 and 2 weeks of oral administration. The most active compounds were found to be symmetrical with four to five methylene groups separating the central ketone functionality and the gem dimethyl or methyl/aryl substituents. Furthermore, biological activity was found to be greatest in both in vivo and in vitro assays for the tetramethyl-substituted keto diacids and diols (e.g., 10c, 10g, 14c), and the least active were shown to be the bis(arylmethyl) derivatives (e.g., 10e, 10f, 14f). Compound 14c dose-dependently elevated HDL-cholesterol, reduced triglycerides, and reduced NEFA, with a minimum effective dose of 30 mg/kg/day. Compound 10g dose-dependently modified non-HDL-cholesterol, triglycerides, and nonesterified fatty acids, with a minimum effective dose of 10 mg/kg/day. At this dose, compound 10g elevated HDL-cholesterol levels 2−3 times higher than pretreatment levels, and a dose-dependent reduction of fasting insulin and glucose levels was observed.

Long hydrocarbon chain ethers with bis-terminal hydroxyl or carboxyl groups have been synthesized and evaluated for their potential to favorably alter lipid disorders including metabolic syndrome. Compounds were assessed for their effects on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes as well as for their effects on lipid and glycemic variables in female obese Zucker fatty rats following 1 and 2 weeks of daily oral administration. The most active compounds were found to be symmetrical with four to five methylene groups separating the central ether functionality and the gem dimethyl or methyl/aryl substituents. Biological activity was found to be greatest for tetramethyl-substituted ether diols (e.g., 28 and 31), while bis(arylmethyl) derivatives (e.g., 10, 11, and 27), diethers (e.g., 49, 50, and 56), and diphenyl ethers (e.g., 35 and 36) were the least active. For the most biologically active compound 28, we observed as much as a 346% increase in serum HDL-cholesterol and a 71% reduction in serum triglycerides at the highest dose administered (100 mg/kg) after 2 weeks of treatment. For compound 31 we observed a 69% reduction in non-HDL-cholesterol, accompanied by a 131% increase in HDL-cholesterol and an 84% reduction in serum triglycerides under the same treatment conditions.

Two kinds of near-stoichiometric LiNbO3 crystals (SLN11 and SLN19) were grown by a flux pulling method from stoichiometric melt with addition of 11mol%K2O and 19mol%K2O, respectively. Compared with the congruent melting LiNbO3, the ultraviolet absorption edges of two crystals shift towards shorter wavelengths, and the locations of the OH^- infrared absorption band have obvious change and the bandwidths become greatly narrower. From these experimental results, the Li2O contents are determined indirectly to be about 49.6mol% for SLN11 and 49.9mol% for SLN19, respectively. The Li2O content in SLN19 is very close to the ideal value of 50mol%. The coercive fields of two crystals were measured by the poling method at room temperature. A linear relationship between the Li2O content and the coercive field was fitted. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Additional information is presented for the transformation of a kinetic resolution into a dynamic kinetic resolution of the isobutyl ester 5b to form the acid 2 in high yield and ee via the intermediacy of a thioester 6c, (Pesti, J. A.; Yin, J.; Zhang, L.-H; Anzalone, L. J. Am. Chem. Soc. 2001, 123, 11075−11076.). The development of optimized reaction conditions for the preparation of 6c, its dynamic kinetic resolution to 2, and the scale-up of both reactions into a pilot plant are described.

Apolipoprotein C-IV (apoC-IV), the newest member of the low-molecular-weight apoC group, has been characterized in blood plasma of rabbits, in which it is a major proline-rich apoC component (Zhang, L-H., L. Kotite, and R. J. Havel. 1996. Identification, characterization, cloning, and expression of apoC-IV, a novel sialoglycoprotein of rabbit plasma lipoproteins. J. Biol. Chem. 271: 1776-1783). Although the decoded sequence of mouse and human apoC-IV is known, apoC-IV has not been identified in blood plasma from these or other species. Rabbit apoC-IV exists in several sialoforms, and the asialoform has an acidic isoelectric point. We show that apoC-IV is a basic protein in human, monkey, and mouse plasma, present as a minor apoC component of VLDL. Human apoC-IV, isolated from apo VLDL by DEAE-cellulose chromatography and two-dimensional electrophoresis, was identified by microsequencing four tryptic peptides. The protein exhibits two major isoforms; one is N-glycosylated, and both are variably sialylated. In normolipidemic plasma, greater than 80% of the protein is in VLDL (0.7% of total apo VLDL), with most of the remainder in HDL. The concentration of apoC-IV in the plasma and lipoproteins of rho < 1.21 g/ml is closely related to plasma triglyceride concentration up to 1,770 mg/dl, varying from 0.1-1.9 mg/dl. Neither the human nor rabbit apoC-IV gene contains a typical TATA box in the 5'-flanking region, but the 5'-untranslated region of the rabbit gene contains a unique purine-rich sequence, GGGACAG(G/A), repeated nine times in tandem, with an additional two within the 5'-flanking sequence. This sequence, functioning as a GAGA box that has been implicated in the transcription of a number of genes, may explain the higher level of expression of apoC-IV in rabbits.

Peptide−oligonucleotide conjugates were synthesized using two strategies:  a mimetic signal peptide-conjugated oligonucleotide was assembled stepwise on CPG by using 2,2-dimethyl-3-hydroxypropionic acid as a linker. To solve the precipitation problem in the coupling reaction caused by the electrostatic interaction of arginine-rich peptides and oligonucleotide, oligonucleotides were absorbed on an anion-exchange resin, and then the on-resin fragment was applied for the conjugation with arginine-rich peptide. The peptide−antisense oligonucleotides showed permeability to the cell membrane of HepG-2 cells.

Cyclic ADP-ribose (cADPR) is not only a potent endogenous calcium modulator but also a second messenger. However, studies on the mechanism of cADPR action were limited due to its instability and lack of available structural modifications in the N¹-glyosyl unit of cADPR. In the present work, a series of N¹-glycosyl mimics with different configurational glycosyls or an ether strand were designed and synthesized mimicking the furanose ring. SN2 substitutions were carried out between the protected inosine and glycosyl triflates to form the N¹-glycosylinosine derivatives, accompanied with some O⁶-glycosyl-substituted as side products. The intramolecular cyclization was followed the strategy described by Matsuda et al. It was found that the 8-unsubstituted substrate could also be used to construct the intramolecular cyclic pyrophosphate. The activities of N¹-glycosyl-substituted cADPR mimics were evaluated by induced Ca²⁺ release in rat brain microsomes and HeLa cells. It was found that the configuration of the N¹-glycosyl moiety in cADPR is not a critical structural factor for retaining the activity of mobilizing Ca²⁺ release. More interestingly, the N¹-acyclic analogue 6 exhibited strong activity by inducing Ca²⁺ release in both rat brain microsomes and HeLa cells. It constitutes a useful tool for further studies.

This paper reports a hospital-based longitudinal study that was conducted in Zibo, China, in June 1996. The objective was to investigate the existing patterns of breastfeeding, amenorrhea and contraceptive use among postpartum women in urban areas of China. Information was obtained from 492 newly parturient women. Follow-up interviews were done at 42 days. 4 months and 1 year after delivery. The results showed that the full breastfeeding rate (including exclusive and almost exclusive breastfeeding) was 78% and 43% at 42 days and 4 months after delivery, respectively. The mean reported length of abstinence from sexual intercourse after delivery was 71 days. The mean reported time to menses resumption was 184 days. Ninety-three per cent of women had resumed sexual intercourse at 4 months after delivery. Seventy-three per cent of women were using contraceptive methods when they resumed sexual activity after delivery. After childbirth, the majority of the women interviewed used condoms within 3 months. Thereafter, most of them switched to intrauterine device (IUD). Life table analysis shows that the continuation rates of full breastfeeding and amenorrhea at 4 months after delivery were 35% and 68%, respectively. This implies that if the full breastfeeding rate can be prolonged, it is feasible to use the lactational amenorrhea method (LAM) among Chinese postpartum women. The policy implications of this study are that quality care on contraceptive services and information for postpartum women in urban areas need to be improved further.

A simple procedure for the preparation of oligonucleotide−peptide conjugate was developed. p-Hydroxy-benzoic acid was used as a linker for the connection of the fragments of peptide and oligonucleotide. It was found that such formed linkage was stable under the conditions of conjugate synthesis. The designed conjugate targeting to GLUT-1 showed up to 50% inhibition of cell proliferation in HepG-2 and MCF-7 cells. Comparing to the results from the expressed antisense RNA in cancer cells, it was proposed that the conjugate of signal peptide mimic and antisense oligonucleotide could improve the permeability of antisense oligonucleotide through cell membrane.

Oligonucleotides consisting of the isonucleoside repeating unit 2',5'-anhydro-3'-deoxy-3'-(thymin-1-yl)-D-mannitol (4) were synthesized with the monomeric unit 4 incorporated into oligonucleotides as 1'-->4' linkage 4a (oligomer I) or 6'-->4' linkage 4b (oligomer II). The hybrid properties of the two oligonucleotides I and II with their complementary strands were investigated by thermal denaturation and CD spectra. Oligonucleotide I (4a) formed a stable duplex with d(A)(14) with a slightly reduced T(m) value of 36.6 degrees C, relative to 38.2 degrees C for the control duplex d(T)(14)/d(A)(14), but oligomer II (4b) failed to hybridize with a DNA complementary single strand. The spectrum of the duplex oligomer I/d(A)(14) showed a positive CD band at 217 nm and a negative CD band at 248 nm attributable to a B-like conformation. Molecular modeling showed that in the case of oligomer I: the C6' hydroxy group of each unit could be located in the groove area when hybridized to the DNA single strand, which might contribute additional hydrogen bonding to the stability of duplex formation.

Unlike other members of the genus, Echinococcus granulosus is known to exhibit considerable levels of variation in biology, physiology and molecular genetics. Indeed, some of the taxa regarded as ‘genotypes’ within E. granulosus might be sufficiently distinct as to merit specific status. Here, complete mitochondrial genomes are presented of 2 genotypes of E. granulosus (G1–sheep-dog strain: G4–horse-dog strain) and of another taeniid cestode, Taenia crassiceps. These genomes are characterized and compared with those of Echinococcus multilocularis and Hymenolepis diminuta. Genomes of all the species are very similar in structure, length and base-composition. Pairwise comparisons of concatenated protein-coding genes indicate that the G1 and G4 genotypes of E. granulosus are almost as distant from each other as each is from a distinct species, E. multilocularis. Sequences for the variable genes atp6 and nad3 were obtained from additional genotypes of E. granulosus, from E. vogeli and E. oligarthrus. Again, pairwise comparisons showed the distinctiveness of the G1 and G4 genotypes. Phylogenetic analyses of concatenated atp6, nad1 (partial) and cox1 (partial) genes from E. multilocularis, E. vogeli, E. oligarthrus, 5 genotypes of E. granulosus, and using T. crassiceps as an outgroup, yielded the same results. We conclude that the sheep-dog and horse-dog strains of E. granulosus should be regarded as distinct at the specific level.

Two disulfide-based phospholipid dimers have been synthesized (PC¹⁴PC¹⁴ and PC¹⁶PC¹⁶), which have packing behavior, melting temperatures, and monomer unit structures that mimic those of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Examination of the mixing behavior of PC¹⁶ and an analogous phosphatidylglycerol (PG) mimic, by use of the nearest-neighbor recognition method, has revealed that these lipids are ideally miscible in the physiologically relevant fluid phase. Addition of a hydrocarbon chain length mismatch of four methylenes per acyl chain and/or the addition of 29 mol % cholesterol do not alter such miscibility. In contrast, the inclusion of a basic peptide (pentalysine) affords a modest degree of nearest-neighbor recognition. The introduction of exchangeable phospholipid dimers that mimic phosphatidylcholines significantly expands the scope of the nearest-neighbor recognition method and increases its relevance to the study of animal cell membranes, whose two-dimensional structures remain to be elucidated.

The use of partially quaternized, chloromethylated polystyrene as a covalent scavenger of cholate ion in aqueous media has been demonstrated. The ability of such polymers to scavenge organic anions by covalent as well as by ionic means has important implications in the areas of medicinal and environmental chemistry, which are briefly discussed.

A series of cross-linked polymers have been synthesized by reaction of 2% cross-linked, chloromethylated polystyrene with a tertiary amine derivative (7) of cholic acid (prepared by reaction of cholic acid methyl ester with N,N-dimethyl-ethylenediamine), followed by exhaustive quaternization with trimethylamine. Increased loadings of 7 result in enhanced binding of taurocholate ion and a decrease in its rate of release upon exposure to 50 mM aqueous NaCl. Examination of particle-size effects indicates that film diffusion and particle diffusion both contribute to the observed kinetics. Interruption tests that were carried out confirmed that particle diffusion is kinetically important. The relevance of this bioconjugate approach to the design of bile acid sequestrants for the treatment of hypercholesterolemia is briefly discussed.

The existence of oxygen vacancy has a significant effect on the structural and electronic properties of Li2CoSiO4. Herein, the formation energy of an oxygen vacancy (VO) in Li2CoSiO4in different oxidation environments is calculated by using a first-principles method. The increased temperature, decreased oxygen partial pressure, and the increased charge state of O vacancy reduce the formation energy of the oxygen vacancy. The presence of VOis accompanied by a distinct redistribution of the electronic charge densities only around the Co and Si ions next to the O-vacancy site, which shows a very local influence on the host material arising from VO. Furthermore, the existence of vacancy defects (VLi1,VLi2,VCoand VSi) in the vicinity of the O vacancy are found to be beneficial to the formation of the O vacancy. The substitutional defects, MnCoand NiCo,near the O vacancy are found to increase the formation energy of the oxygen vacancy, however, FeCodecreases the formation energy of the O vacancy.

Polymerase chain reaction–ribosomal ITS-1 DNA (rDNA) restriction fragment length polymorphism (PCR–RFLP) analysis and sequencing of the mitochondrial cytochrome c oxidase subunit 1 (CO1) and NADH dehydrogenase 1 (ND1) genes were used to characterize 33 Echinococcus granulosus isolates collected from different regions and hosts in Argentina, and to determine which genotypes occurred in humans with cystic hydatid disease. The results of the study demonstrated the presence of at least 4 distinct genotypes; the common sheep strain (G1) in sheep from Chubut Province and in humans from Río Negro Province, the Tasmanian sheep strain (G2) in sheep and 1 human from Tucumán Province, the pig strain (G7) in pigs from Santa Fe Province and the camel strain (G6) in humans from Río Negro and Buenos Aires Provinces. The finding that pigs harboured the pig strain and the occurrence of the Tasmanian sheep strain has considerable implications for the implementation of hydatid control programmes due to the shorter maturation time of both strains in dogs compared with the common sheep strain. Furthermore, this is the first report of the presence of the G2 and G6 genotypes in humans which may also have important consequences for human health.

Murine antibodies, raised against a purified recombinant 30 kDa laminin-binding protein from Echinococcus granulosus, were used to investigate the tissue distribution of the native protein in protoscoleces and brood capsules. Immunofluorescence, in combination with confocal microscopy, revealed that the protein was distributed in small annular foci near the peripheral regions of the protoscoleces. Immunoelectron microscopy of thawed cryosections demonstrated that the laminin-binding protein was present in the cytoplasm of tegumentary cytons and myocytons, but not in cells of the excretory system. The protein was associated with amorphous regions of the cytoplasm, and was not expressed at the surfaces of cells. This distribution resembles those of other invertebrate laminin-binding proteins, which are thought to act in the cell cycle and cell proliferation events. A low degree of label was consistently detected in extracellular matrices of the protoscolex.

Eight bioactive triterpenoid saponins (1−8) were isolated from the seeds of Aesculus chinensis, four of which are novel compounds. The major saponins were identified as escin Ia (1), Ib (2), isoescin Ia (3) and Ib (4), while the new compounds were identified as 22α-tigloyl-28-acetylprotoaescigenin-3β-O-[β-d-glucopyranosyl (1−2)] [β-d-glucopyranosyl (1−4)]-β-d-glucopyranosiduronic acid (escin IVc, 5), 22α-angeloyl-28-acetylprotoaescigenin-3β-O-[β-d-glucopyranosyl (1−2)] [β-d-glucopyranosyl (1−4)]-β-d-glucopyranosiduronic acid (escin IVd, 6), 28-tigloylprotoaescigenin-3β-O-[β-d-glucopyranosyl (1−2)] [β-d-glucopyranosyl (1−4)]-β-d-glucopyranosiduronic acid (escin IVe, 7), and 28-angeloylprotoaescigenin-3β-O-[β-d-glucopyranosyl (1−2)] [β-d-glucopyranosyl (1−4)]-β-d-glucopyranosiduronic acid (escin IVf, 8). The structures were determined by chemical and spectroscopic methods. All the above compounds were evaluated for their inhibitory activity against HIV-1 protease.

Newly synthesized p-dioctadecanoylcalix[4]arene is shown to form stable monolayers at the air/water interface over a wide pH range (1.8−12). Surface pressure−area isotherms obtained with the Wilhelmy plate technique are used to infer that the molecular packing at the onset of film collapse is consistent with a conelike conformer having all of the phenol oxygens of the calixarenes adsorbed to the interface. Increasing pH leads to a stepwise dissociation to phenoxides and attendant expansion of the monolayer attributable to enhanced electrostatic repulsions among the negatively charged phenoxide polar heads. Analysis of the area per molecule as a function of pH reveals two distinct steps and an intermediate plateau. Considering the presence of two types of chemically inequivalent phenol groups and the potential for intramolecular hydrogen bonding, this behavior was interpreted in terms of acid−base equilibria in which the first step corresponds to an apparent surface pKa,1 ≈ 6.4 while the second step is consistent with an apparent surface pKa,2 ≈ 9.2 (assuming pKa,3, pKa,4 ≫ 12). As for the dynamics of the monolayers, the technique of surface light scattering (SLS) was employed to probe the surface viscoelasticity. Although pH had a dramatic effect on the molecular packing of p-dioctadecanoylcalix[4]arene monolayers, SLS results indicate that all films exhibited the limiting behavior of infinite lateral modulus dynamics when the surface pressure exceeds 1 mN·m^-1, and such behavior is established to be independent of pH. From these findings, it is deduced that the packing of the aromatic rings and long octadecanoyl side chains, rather than electrostatic interactions of the phenoxide headgroups, is responsible for the lateral rigidity of such monolayers.

The static and dynamic properties of p-dioctadecanoylcalix[4]arene monolayers on the air/water interface are examined relative to the effects of inorganic and polymeric counterions (i.e., spermine, poly(ethylenimine), and poly(l-lysine)) in the subphase over a large range of pH. The methods adopted are the techniques of the Wilhelmy plate and surface light scattering (SLS). At moderate subphase pH values, 3.5−10, the polyions significantly expand the monolayer but do not appreciably change the monolayer surface viscoelasticity as detected by SLS. A scheme of complex formation and acid−base equilibrium is used to explain the surface pressure isotherms while strong lateral packing interactions of the hydrophobic chains and aromatic rings, which predominate over the electrostatic interactions of the phenoxide rings of calixarene, are invoked to explicate the viscoelastic properties. Simple univalent inorganic ions do not show any specific effects on either the static or dynamic properties of these monolayers.

Abstract:  Bermudagrasses (Cynodon spp.) are major turfgrasses for home lawns, public parks, golf courses and sport fields, and are widely adapted to tropical and warmer temperate climates. Morphological and physiological characteristics are not sufficient to differentiate some bermudagrass genotypes because the differences between them are often subtle and subject to environmental influence. In this study, a DNA-typing technique, amplified fragment length polymorphism (AFLP), was used to differentiate bermudagrass genotypes and to explore their genetic relationships. Twenty seven bermudagrass cultivars and introductions, mostly from the Coastal Plain Experiment Station in Tifton, Ga., were assayed by the radioactive (32P) and the fluorescence-labeled AFLP methods. The AFLP technique produced enough polymorphism to differentiate all 27 bermudagrass genotypes, even the closely related ones. An average of 48–74 bands in the 30–600-bp size range was detected by the 32P-labeled AFLP method. The results indicated that most of the 14 primer combinations tested in this study could be used to distinguish bermudagrass genotypes, and that some single primer-pairs could differentiate all 27 of them. To test the reliability and reproducibility of the AFLP procedure, three DNA isolations (replications) of the 27 bermudagrass genotypes were assayed using five primer pairs. Only 0.6% of the bands were evaluated differently among the three replications. One replication of one genotype (which was most likely a planting contaminant) was grouped in an unexpected cluster using the Unweighted Pair Group Mean Average (UPGMA) method. A one- or two-band difference in scoring did not change the clustering of genotypes or the replications within genotypes. The 27 genotypes were grouped into three major clusters, many of which were in agreement with known pedigrees. Trees constructed with different primer combinations using 32P- and fluorescence-labelling formed similar major groupings. The semi-automated fluorescence-based AFLP technique offered significant improvements on fragment sizing and data handling. It was also more accurate for detection and more efficient than the radioactive labelling method. This study shows that the AFLP technique is a reliable tool for differentiating bermudagrass genotypes and for determining genetic relationships among them.

The problem of plane stress crack growth in a rectangular linearly viscoelastic plate under a pair of equal and opposite forces applied to the crack surface is studied experimentally. A fatigue crack is generated at the end of a slot cut on the specimen. After application of two opposite forces to the specimen with a fatigue crack, the crack grows gradually. It is found that under sufficiently small load, the speed of crack growth decreases as time increases, and crack arrest occurs finally. However when the applied load is sufficiently large, the crack grows with increasing speed until a catastrophic failure of the specimen takes place. Between these two extreme cases, the crack grows with an oscillatory speed. A theory based on the models of an infinite plate and double cantilevers is proposed for the explanation of the behaviour of crack growth under various loads. Our experimental results check fairly well with theoretical predictions.

Twenty-eight isolates of E. granulosus, collected from humans at surgery, and a range of intermediate hosts, including sheep, cattle and camels from abattoirs in North and South Xinjiang Uygur Autonomous Region, People's Republic of China, were analysed for DNA sequence variation within regions of the mitochondrial cytochrome c oxidase I (COI) and NADH dehydrogenase subunit I (NDI) genes. The isolates were categorized into 2 distinct and uniform genotypic groupings, based on the sequences obtained, and the data clearly indicated that the camel/dog strain (G6 genotype) of E. granulosus as well as the cosmopolitan, common sheep strain (G1 genotype) occur in north Xinjiang. The presence of the camel strain has thus been confirmed in Xinjiang but it is evident from this and a previous molecular genetic survey of E. granulosus isolates from north-western China that the common sheep strain is the most predominant in the region. From the public health perspective, the majority of infected livestock will act as reservoirs of human infection there. During the course of the study, a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) assay, based on the NDI sequence variation, was developed that allows rapid discrimination of the G1 and G6 genotypes.

Detergent-soluble DNA is the fraction (2-4%) of DNA that is released into the supernate upon mild detergent lysis. It is nonmitochondrial in origin. It labels efficiently with deoxy[3H]ribonucleosides and the labeling is prevented by inhibitors of polymerase alpha and ribonucleotide reductase. In previous publications we have characterized detergent-soluble DNA from splenocytes of immunologically activated mice. In this publication we show that incorporation of [3H]thymidine into detergent-soluble DNA is prevented by pretreatment with novobiocin, 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA), and teniposide (VM26), three inhibitors of type II topoisomerases. Camptothecin, an inhibitor of type I topoisomerases, also reduces incorporation of [3H]thymidine but only to 50% of control levels. In addition to affecting incorporation of [3H]thymidine, preincubation with the topoisomerase II inhibitors m-AMSA and VM26 alters the amount of DNA recovered in the detergent-soluble fraction. At low concentrations of m-AMSA the amount of detergent-soluble DNA increases somewhat, whereas at higher drug concentrations a marked decrease is observed. Treatment with VM26 results in diminished amounts of DNA being released into the detergent-soluble fraction as well. However, maximal inhibition of detergent-soluble DNA release by VM26 requires the presence of camptothecin. Therefore, we suggest that topoisomerases play an important role in making a small part of lymphocyte chromatin detergent labile. Furthermore, these results are consistent with recent studies demonstrating a role for topoisomerases in yeast replication. Thus, the newly synthesized portion of detergent-soluble DNA may arise as DNA replication intermediates not yet stabilized into mature chromatin.

This paper reports the design and synthesis of 5,11,17,23,29,35-hexaacetyl-37,38,39,40,41,42-hexakis(1-hexadecyloxy)calix[6]arene (2) and 5,11,17,23-tetraamideoxime-25,26,27,28-tetrakis(1-hexadecyloxy)calix[4]arene(3), plus a detailed comparison of the membrane properties of corresponding Langmuir−Blodgett films with those assembled from 5,11,17,23,29,35-hexaamideoxime-37,38,39,40,41,42-hexakis(1-hexadecyloxy)calix[6]arene (1a). Surface pressure−area isotherms that were recorded for 1a and 2 over a pure water subphase at 25 °C showed significant hysteresis that was eliminated after two compression−expansion cycles; the limiting area in both cases was ca. 162 Ų/molecule. In sharp contrast, 3 showed no hysteresis at 25 °C and a limiting area of 107 Ų/molecule. Careful examination of the dependence of surface viscosity on temperature has provided compelling evidence for a solid-analogous to liquid-analogous phase transition occurring at 31 and 28 °C for monolayers of 1a and 2, respectively. Permeation measurements that were made across Langmuir−Blodgett (LB) films [four monolayers supported on poly[1-(trimethylsilyl)-1-propyne] with respect to helium and nitrogen] revealed high selectivity in the case of 1a and much lower selectivity with 2 and 3 at ambient (21−23 °C) temperatures. The implications of these findings, in terms of the further development of LB films as membranes for gas separations, are briefly discussed.

Bay o 2752 [N,N'-(1, 11-undecandiyl)bis(2,3-dihydro-2-methyl-1H-indole-1-carboxamide)] has been demonstrated in rats to inhibit intestinal cholesterol absorption. Studies were carried out in male Wistar rats to determine if the mechanism is inhibition of intestinal bile acid absorption or cholesterol esterification. Bay o 2752 did not alter intestinal bile acid absorption as measured by in vitro uptake of [14C]taurocholic acid into ileal everted sacs (0.01 and 1.0 mg/ml of Bay o 2752) or the biliary excretion of radioactivity after in vivo ileal perfusion of the bile acid and drug (1.0 mg/ml at 1.0 ml/min for 1 hr). Cholesterol esterification was determined by measurement of in vitro activity of acyl coenzyme A:cholesterol acyltransferase from hepatic microsomes and cholesterol ester hydrolase from pancreatic supernatant, and the in vivo lymphatic output of cholesteryl ester after intraduodenal cholesteryl infusion. Addition of Bay o 2752 (0.01-10 micrograms/ml) to hepatic microsomes produced a concentration-dependent decrease in acyl coenzyme A:cholesterol acyltransferase activity with an IC50 of 0.95 micrograms/ml. Cholesterol ester hydrolase activity was unaffected by the drug (1.0-100 micrograms/ml). Intraduodenal infusion of Bay o 2752 (10 mg/ml at 0.9 ml/hr for 8 hr) reduced markedly the flux of cholesterol from the intestinal lumen into the mesenteric lymph, especially the lymphatic output of the esterified form of both radioisotopically labeled and total cholesterol. These data suggest that Bay o 2752-induced reduction in intestinal cholesterol absorption results from its potent inhibitory effect on acyl coenzyme A:cholesterol acyltransferase activity.