Oxynitride K2Ba6.72Si16O40-1.5yNy:0.28Eu2+ phosphor with high thermal stability realized by crystal field engineering

Extensive research has gone into modifying the chemical composition of phosphors to achieve desirable optical properties. Here, oxynitride phosphors K2Ba6.72Si16O40-1.5yNy:0.28Eu2+ were synthesized by introducing N3- (y) into a K2Ba6.72Si16O40:0.28Eu2+ lattice. An uneven shrinking of the cell parameters a, b, and c was observed through a combination of X-ray diffraction studies and Rietveld refinements. This shrinking caused a large centroid shift (εc) and splitting of the 5d energy level (εcfs), thus inducing the broadening of the excitation spectra (104 → 127 nm, y = 0 → y = 12) and the red shift of the emission spectra (501 → 543 nm, y = 0 → y = 12). The modified series of samples have a broad excitation spectrum, suitable of use in UV, near-UV, and blue light-emitting LEDs. In addition, the optimal sample, K2Ba6.72Si16O31N6:0.28Eu2+, benefits from an increased activation energy and thermal stability.

Laser-direct-drive fusion target design with a high-Z gradient-density pusher shell

Laser-direct-drive fusion target designs with solid deuterium-tritium (DT) fuel, a high-Z gradient-density pusher shell (GDPS), and a Au-coated foam layer have been investigated through both 1D and 2D radiation-hydrodynamic simulations. Compared with conventional low-Z ablators and DT-push-on-DT targets, these GDPS targets possess certain advantages of being instability-resistant implosions that can be high adiabat (α≥8) and low hot-spot and pusher-shell convergence (CR_{hs}≈22 and CR_{PS}≈17), and have a low implosion velocity (v_{imp}<3×10^{7}cm/s). Using symmetric drive with laser energies of 1.9 to 2.5MJ, 1D lilac simulations of these GDPS implosions can result in neutron yields corresponding to ≳50-MJ energy, even with reduced laser absorption due to the cross-beam energy transfer (CBET) effect. Two-dimensional draco simulations show that these GDPS targets can still ignite and deliver neutron yields from 4 to ∼10MJ even if CBET is present, while traditional DT-push-on-DT targets normally fail due to the CBET-induced reduction of ablation pressure. If CBET is mitigated, these GDPS targets are expected to produce neutron yields of >20MJ at a driven laser energy of ∼2MJ. The key factors behind the robust ignition and moderate energy gain of such GDPS implosions are as follows: (1) The high initial density of the high-Z pusher shell can be placed at a very high adiabat while the DT fuel is maintained at a relatively low-entropy state; therefore, such implosions can still provide enough compression ρR>1g/cm^{2} for sufficient confinement; (2) the high-Z layer significantly reduces heat-conduction loss from the hot spot since thermal conductivity scales as ∼1/Z; and (3) possible radiation trapping may offer an additional advantage for reducing energy loss from such high-Z targets.

Whole-Genome Sequencing of Fusarium oxysporum f. sp. cucumerinum Strain Race-4 Infecting Cucumber in China

Fusarium oxysporum f. sp. cucumerinum, which causes root and vascular wilting, is one of the most devastating diseases infecting cucumber. Here, we report the first genome resource with high-quality assembly for F. oxysporum f. sp. cucumerinum strain Race-4, which is primarily endemic to China. The genome was 59.11 Mb in size and consisted of 48 scaffolds with an N50 of 3.87 Mb using PacBio long reads (301.77×) sequencing, and encodes 14,898 proteins from analyzing RNA-seq data. Gene annotations identified pathogen-host interaction genes, fungal virulence factors, secreted proteins, transcription factors, and secondary metabolite biosynthesis gene. Moreover, functional genes reported in previous studies were also identified in the genome of Race-4. These genes and genome resource may play important roles in understanding F. oxysporum f. sp. cucumerinum-cucumber interactions and will be useful for further research.

The vegetable SNP database: An integrated resource for plant breeders and scientists

Single nucleotide polymorphisms (SNPs) are widely used in genetic research and molecular breeding. To date, the genomes of many vegetable crops have been assembled, and hundreds of core germplasms for each vegetable have been sequenced. However, these data are not currently easily accessible because they are stored on different public databases. Therefore, a vegetable crop SNP database should be developed that hosts SNPs demonstrated to have a high success rate in genotyping for genetic research (herein, "alpha SNPs"). We constructed a database (VegSNPDB, http://www.vegsnpdb.cn/) containing the sequence data of 2032 germplasms from 16 vegetable crop species. VegSNPDB hosts 118,725,944 SNPs of which 4,877,305 were alpha SNPs. SNPs can be searched by chromosome number, position, SNP type, genetic population, or specific individuals, as well as the values of MAF, PIC, and heterozygosity. We hope that VegSNPDB will become an important SNP database for the vegetable research community.

Target SSR-Seq: A Novel SSR Genotyping Technology Associate With Perfect SSRs in Genetic Analysis of Cucumber Varieties

Simple sequence repeats (SSR) - also known as microsatellites - have been used extensively in genetic analysis, fine mapping, quantitative trait locus (QTL) mapping, as well as marker-assisted selection (MAS) breeding and other techniques. Despite a plethora of studies reporting that perfect SSRs with stable motifs and flanking sequences are more efficient for genetic research, the lack of a high throughput technology for SSR genotyping has limited their use as genetic targets in many crops. In this study, we developed a technology called Target SSR-seq that combined the multiplexed amplification of perfect SSRs with high throughput sequencing. This method can genotype plenty of SSR loci in hundreds of samples with highly accurate results, due to the substantial coverage afforded by high throughput sequencing. We also detected 844 perfect SSRs based on 182 resequencing datasets in cucumber, of which 91 SSRs were selected for Target SSR-seq. Finally, 122 SSRs, including 31 SSRs for varieties identification, were used to genotype 382 key cucumber varieties readily available in Chinese markets using our Target SSR-seq method. Libraries of PCR products were constructed and then sequenced on the Illumina HiSeq X Ten platform. Bioinformatics analysis revealed that 111 filtered SSRs were accurately genotyped with an average coverage of 1289× at an extremely low cost; furthermore, 398 alleles were observed in 382 cucumber cultivars. Genetic analysis identified four populations: northern China type, southern China type, European type, and Xishuangbanna type. Moreover, we acquired a set of 16 core SSRs for the identification of 382 cucumber varieties, of which 42 were isolated as backbone cucumber varieties. This study demonstrated that Target SSR-seq is a novel and efficient method for genetic research.

Detection of porcine circovirus-like virus P1 in Hebei, China

Porcine circovirus-like virus P1 is a novel unclassified circovirus that was first detected in China and may be associated with post-weaning multisystemic wasting syndrome (PMWS) and congenital tremor. In this study, we detected P1 infection in pigs in Hebei Province, China, in 2017. One hundred and forty of 500 (28.0%) serum samples from 25 pig farms with different PMWS status in seven cities were P1 positive on PCR. Twelve P1 strains were sequenced, and the complete genomes of 11 P1 strains were 648 nucleotides (nt) in length, whereas that of strain ZJK02 was 647 nt, with a G deletion at position of 183 in its genome. The complete genomic and capsid protein sequences of the 12 P1 strains analysed in this study shared 98.8%-100.0% and 86.5%-100.0% identity, respectively. A phylogenetic analysis based on the complete genomic and capsid sequences of 26 P1 strains showed that the 12 P1 sequences from Hebei Province clustered on two small branches. Further studies of the evolution and pathogenesis of P1 are required.

CsATAF1 Positively Regulates Drought Stress Tolerance by an ABA-Dependent Pathway and by Promoting ROS Scavenging in Cucumber

The NAC transcription factors play vital roles in responding to drought stress in plants; however, the molecular mechanisms remain largely unknown in cucumber. Suppression of CsATAF1 via RNA interference (RNAi) weakened drought stress tolerance in cucumber due to a higher water loss rate in leaves, a higher level of hydrogen peroxide (H2O2) and superoxide radicals (O2·-), increased malondialdehyde (MDA) content, lower Fv/Fm ratios and lower antioxidant enzyme activity. The analysis of root length and stomatal apertures showed that CsATAF1-RNAi cucumber plants were less responsive to ABA. In contrast, CsATAF1-overexpression (OE) plants showed increased drought stress tolerance and sensitivity to ABA. Quantitative PCR (qPCR) analysis showed that expression of several stress-responsive genes was significantly up-regulated in CsATAF1-OE transformants and down-regulated in CsATAF1-RNAi transformants. CsABI5, CsCu-ZnSOD and CsDREB2C were verified as direct target genes of CsATAF1. Yeast one-hybrid analysis and electrophoretic mobility shift assay (EMSA) further substantiated that CsATAF1 bound to the promoters of CsABI5, CsCu-ZnSOD and CsDREB2C. Transient expression in tobacco leaves and cucumber protoplasts showed that CsATAF1 directly up-regulated the expression of CsABI5, CsCu-ZnSOD and CsDREB2C. Our results demonstrated that CsATAF1 functioned as a positive regulator in response to drought stress by an ABA-dependent pathway and decreasing reactive oxygen species (ROS) accumulation in cucumber.

Comparative analysis of miRNA and mRNA abundance in determinate cucumber by high-throughput sequencing

Determinate cucumber is a type of short vines, fewer nodes, and terminal flowers, it is suitable for high-density planting and available harvesting in field cultivation, whereas the indeterminate cucumber is preferred to cultivate in greenhouses. However, many biotic or abiotic stresses could lead indeterminate cucumber to be determinate in greenhouse cultivation, which may decrease yield and fruit quality. Therefore, it is urgent and essential to investigate the key factors forming determinate and terminal flowering in cucumber. In this study, two close background inbred lines were selected and conducted the miRNA and mRNA high throughput sequencing. Interestingly, ethylene-associated miRNAs and mRNAs were intensively obtained, indicating that the plant hormone ethylene is a key factor impacting determinate and terminal flowering in cucumber. The ethylene metabolites analysis showed that significant higher ethylene was observed in determinate line than that in the indeterminate line. The RT-qPCR validation of ethylene related miRNAs Cas-miR172, Cas-miR396, and Cas-miR414 and their target mRNAs showed a significant negative correlation. These data suggested that ethylene-associated miRNAs might affect determinate and terminal flower phenotypes by regulating their target genes expression. This study not only provides a potential molecular mechanism for determinate formation in cucumber but also establishes a method to demonstrate important physiological processes through the comprehensive association of miRNA and mRNA high-throughput sequencing.

Orange phosphor Li2SrSiON2:Eu2+ for blue light chip based warm white LEDs

Crystal structure and luminescence properties of LSSON:Eu²⁺ have been investigated.

Role of 5 Saponins in Secretion of Cytokines by PRRSV-induced Endothelial Cells

The aim of the research presented here was to investigate the immunoloregulatory effects of 5 saponins: Saikosaponins A (SSA) and D (SSD) from Bupleurum chinese DC (Umbelliferae), Panax Notoginseng Saponin (PNS) and Notoginsenoside R1 from Panax notoginseng (Araliaceae) (SR1), and Anemoside B4 from Pulsatilla chinensis Regel (Ranunculaceae) (AB4). To achieve this, endothelial cells were challenged with 10(5) TCID50/mL PRRSV for 24 h then treated respectively with 5 saponins at 3 concentrations (1, 5 and 10 μg/mL). The cells were incubated at 37°C in a cell incubator for 24 h. The supernatants were collected and analyzed the levels of interleukin-4 (IL-4), IL-10, IL-2, and γ-interferon (IFN-γ) by ELISA kits. The results revealed that PNS and SR1 inhibited the production of IL-4; PNS, SR1 and SSD inhibited the secretion of IL-10; SSA, SSD and AB4 up-regulated IL-2 expression; SSA and SSD increased the level of IFN-γ. All these changes were significant. Taken together, the data suggested that these 5 saponins might effectively regulate immune responses via changes in the levels of these select cytokines.

Identification and characterisation of Dof transcription factors in the cucumber genome

Cucumber is vulnerable to many foliage diseases. Recent studies reported cloning of candidate genes for several diseases in cucumber; however, the exact defence mechanisms remain unclear. Dof genes have been shown to play significant roles in plant growth, development, and responses to biotic and abiotic stresses. Dof genes coding for plant-specific transcription factors can promote large-scale expression of defence-related genes at whole genome level. The genes in the family have been identified and characterized in several plant species, but not in cucumber. In the present study, we identified 36 CsDof members from the cucumber draft genomes which could be classified into eight groups. The proportions of the CsDof family genes, duplication events, chromosomal locations, cis-elements and miRNA target sites were comprehensively investigated. Consequently, we analysed the expression patterns of CsDof genes in specific tissues and their response to two biotic stresses (watermelon mosaic virus and downy mildew). These results indicated that CsDof may be involved in resistance to biotic stresses in cucumber.

Fine genetic mapping of target leaf spot resistance gene cca-3 in cucumber, Cucumis sativus L

The cucumber target leaf spot resistance gene cca - 3 was fine mapped in a 79-kb region harboring a CC-NB-ARC type R gene that may be responsible for the hypersensitive responses to infection of the target leaf spot pathogen in cucumber. The target leaf spot (TLS) is one of the most important foliar diseases in cucumber (Cucumis sativus L.). In this study, we conducted fine genetic mapping of a simply inherited recessive resistance gene, cca-3 against TLS with 193 F2:3 families and 890 F2 plants derived from the resistant cucumber inbred line D31 and the susceptible line D5. Initial mapping with microsatellite markers and bulked segregant analysis placed cca-3 in a 2.5-Mbp region of cucumber chromosome 6. The D5 and D31 lines were re-sequenced at 10× genome coverage to explore new markers in the target region. Genetic mapping in the large F2 population delimited the cca-3 locus in a 79-kb region with flanking markers Indel16874230 and Indel16953846. Additional fine mapping and gene annotation in this region revealed that a CC-NB-ARC type resistance gene analog, Csa6M375730, seems to be the candidate gene for cca-3. One single nucleotide polymorphism (SNP) was found in the NB-ARC domain of this candidate gene sequence between D31 and D5 that may lead to amino acid change, thus altering the function of the conserved NB-ARC motif. This SNP was validated in the segregating population as well as 24 independent cucumber lines. There was significantly higher level of cca-3 expression in the leaves of D5 (susceptible) than in D31 (resistant), and the expression level was positively correlated with the areas of necrotic spots on leaves after inoculation. It seems the cca-3 resistance gene was able to induce hypersensitive responses to the infection by TLS pathogen.

Synthesis, structure, and luminescence properties of SrSiAl2O3N2:Eu2+ phosphors for light-emitting devices and field emission displays

The crystal structure, band structure, and photoluminescence and cathodoluminescence properties of SrSiAl₂O₃N₂:Eu²⁺ phosphors were investigated.

Effect of a solid solution of AlN on the crystal structure and optical properties of LiSi2N3:Eu phosphors

The solid solutions could be the useful way to improve the luminescence intensity of LiSi₂N₃:Eu phosphors.

Nanopatterning using a simple bi-layer lift-off process for the fabrication of a photonic crystal nanostructure

A simple and versatile method for fabricating nanopatterns by a lift-off procedure is demonstrated. The technique involves the use of molecular transfer lithography based on water-soluble templates to form a nanopatterned UV-curable material on a PMGI layer, which serves as an underlying resin suitable for lift-off processes. This bi-layer procedure is used for the fabrication of nickel patterns, which are subsequently used as a hard mask for plasma etch processing. Using this procedure, a two-dimensional TiO(2) photonic crystal layer with a 450 nm lattice constant is fabricated on Y(3)Al(5)O(12):Ce(3+) (YAG:Ce) yellow ceramic plate phosphor to enhance its forward emission. The yellow emission in the forward direction is improved by a factor of 3.5 compared to that of a conventional non-scattering YAG:Ce phosphor plate excited by a blue LED.

The hypothesis of an effective strategy for resistance of hepatocellular carcinoma to therapy-autophagy

Hepatocellular carcinoma (HCC) is one of the most common malignant tumours and its five-year survival rate remains low. Autophagy is a catabolic process conserved among all eukaryotes ranging from yeast to mammals. Recently, many studies show that tumour cells can utilize autophagy as a cellular defence mechanism when facing metabolic stress. Thus, we hypothesize that autophagy may play an important role in the resistance of hepatocellular carcinomas to therapy. Although the exact role of autophagy on tumour cells is still complex and further studies are needed to prove the impact of autophagy on HCC, it suggests that autophagy may be a new therapeutic target for the resistance to therapy of HCC.

Efficacy and safety of extended-release niacin/laropiprant plus statin vs. doubling the dose of statin in patients with primary hypercholesterolaemia or mixed dyslipidaemia

BACKGROUND

Co-administration of niacin with statin offers the potential for additional lipid management and cardiovascular risk reduction. However, niacin is underutilised because of the side effects of flushing, mediated primarily by prostaglandin D(2) (PGD(2)). A combination tablet containing extended-release niacin and laropiprant (ERN/LRPT), a PGD(2) receptor (DP1) antagonist, offers improved tolerability. This study assessed the efficacy and safety of ERN/LRPT added to statin vs. doubling the dose of statin in patients with primary hypercholesterolaemia or mixed dyslipidaemia who were not at their National Cholesterol Education Program Adult Treatment Panel III low-density lipoprotein cholesterol (LDL-C) goal based on their coronary heart disease risk category (high, moderate or low).

METHODS

After a 2- to 6-week run-in statin (simvastatin 10 or 20 mg or atorvastatin 10 mg) period, 1216 patients were randomised equally to one of two treatment groups in a double-blind fashion: group 1 received ERN/LRPT (1 g) plus the run-in statin dose and advanced to ERN/LRPT (2 g) after 4 weeks for an additional 8 weeks, with no adjustments to the run-in statin dose; group 2 received simvastatin or atorvastatin at twice their run-in statin dose and remained on this stable dose for 12 weeks.

RESULTS

ERN/LRPT added to statin (pooled across statin and statin dose) significantly improved key lipid parameters vs. the doubled statin dose (pooled): the between-treatment group difference in least squares mean per cent change [95% confidence interval (CI)] from baseline to week 12 in LDL-C (primary end-point) was -4.5% (-7.7, -1.3) and in high-density lipoprotein cholesterol (HDL-C) was 15.6% (13.4, 17.9) and in median per cent change for triglyceride (TG) was -15.4% (-19.2, -11.7). Treatment-related adverse experiences (AEs) related to flushing, pruritis, rash, gastrointestinal upset and elevations in liver transaminases and fasting serum glucose occurred more frequently with ERN/LRPT added to statin vs. statin dose doubled.

CONCLUSIONS

The addition of ERN/LRPT to ongoing statin treatment produced significantly improved lipid-modifying benefits on LDL-C, HDL-C and TG and all other lipid parameters compared with doubling the statin dose in patients with primary hypercholesterolaemia or mixed dyslipidaemia. The types of AEs that occurred at a greater frequency in the ERN/LRPT group were those typically associated with niacin.

A semi-automated method for measuring the potential for protein covalent binding in drug discovery

INTRODUCTION

Covalent protein binding of metabolically reactive intermediates of drugs has been implicated in drug toxicity including the occurrence of idiosyncratic drug toxicity. Investigators therefore would prefer to avoid developing compounds that produce significant amounts of reactive metabolites. By incubating the radiolabeled drug of interest with liver microsomes it is possible to evaluate the propensity of a drug candidate to covalently bind to proteins.

METHODS

Here we present a semi-automated method in which a Brandel cell harvester is used to collect and wash proteins that have been incubated with radiolabeled drug. This method utilizes glass fiber filter paper to capture precipitated protein, rather than the more traditional exhaustive extraction/centrifugation approach. Using model compounds (including [14C]diclofenac, [3H]imipramine, [14C]naphthalene, and [14C]L-746530) we compare the covalent binding results obtained using this method to results generated using the traditional method and we performed cross-laboratory testing of assay reproducibility.

RESULTS

It was found that results from new method correlated highly with the traditional method (R2=0.89). The cross-laboratory testing of the method showed an average interlaboratory coefficient of variation of only 18.4%.

DISCUSSION

This method provides comparable results to the more traditional centrifugation-based method with considerable time and labor savings.

Species and gender differences in the formation of an active metabolite of a substituted 2,4-thiazolidinedione insulin sensitizer

1. The metabolism of a substituted 2,4-thiazolidinedione (P1) with dual PPARalpha/gamma activity was evaluated in male and female rats, dogs and monkeys. A para-hydroxylated metabolite (M1) with potent PPARgamma-selective agonist, was a major circulating drug-related component in female rats, dogs and monkeys, but not in male rats (M1-to-P1 exposure ratio of <1, 3-5, 5 and 5-11 in male rat, monkey, female rat, and dog, respectively). 2. M1 (%) formed in vitro (5, 53, 57-65, 67 and 67% in male rat, monkey, female rat, dog, and human liver microsomes, respectively), rank ordered with M1 (%) formed in vivo (24-45, 53-57, 78, 75-85%, for male rat, monkey, female rat and dog, respectively, after oral administration of P1). 3. The plasma clearance of M1 was higher in male rats (32 ml min(-1) kg(-1) compared with 6, 7 and 2 ml min(-1) kg(-1) in female rat, male monkey and male dogs, respectively). 4. The low amounts of M1 observed in male rats, with the appearance of products of the cleavage of the propyl group between the phenyl groups was probably due to the presence of the sex-specific CYP2C11, which cleaves P1 at the propyl bridge. None of the CYPs present in female rats cleaved P1 at this site and M1 was only produced by CYP2C6. In humans, only CYP2C8 and the polymorphic CYP2C19 produced M1.

Use of on-line hydrogen/deuterium exchange to facilitate metabolite identification

Biotransformation studies performed on an investigational compound (I, represented by R1-CH(NH(2))-CO-N(R2)-CH(2)-S-R3) led to the identification of five metabolites (M1-M5). Based on LC/MS (liquid chromatography/mass spectrometry) analysis which included the use of H(2)O and D(2)O in the mobile phases, they were identified as the sulfoxide (M1), sulfone (M2), carbamoyl glucuronide (M3), N-glucuronide (M4), and N-glucoside (M5) metabolites, respectively. The structure of M3, a less commonly seen carbamoyl glucuronide metabolite, was established using on-line H/D (hydrogen/deuterium) exchange experiments conducted by LC/MS. H/D exchange experiments were also used to distinguish the S-oxidation structures of M1 and M2 from hydroxylation. Herein, the application of deuterium oxide as the LC/MS mobile phase for structural elucidation of drug metabolites in biological matrices is demonstrated.

Fossilized high pressure from the Earth's deep interior: the coesite-in-diamond barometer

Mineral inclusions in diamonds provide an important source of information about the composition of the continental lithosphere at depths exceeding 120-150 km, i.e., within the diamond stability field. Fossilized high pressures in coesite inclusions from a Venezuela diamond have been identified and measured by using laser Raman and synchrotron x-ray microanalytical techniques. Micro-Raman measurements on an intact inclusion of remnant vibrational band shifts give a high confining pressure of 3.62 (+/-0.18) GPa. Synchrotron single-crystal diffraction measurements of the volume compression are in accord with the Raman results and also revealed direct structural information on the state of the inclusion. In contrast to olivine and garnet inclusions, the thermoelasticity of coesite favors accurate identification of pressure preservation. Owing to the unique combination of physical properties of coesite and diamond, this "coesite-in-diamond" geobarometer is virtually independent of temperature, allowing an estimation of the initial pressure of Venezuela diamond formation of 5.5 (+/-0.5) GPa.

Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa

We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway.

Slow deformation and lower seismic hazard at the new madrid seismic zone

Global Positioning System (GPS) measurements across the New Madrid seismic zone (NMSZ) in the central United States show little, if any, motion. These data are consistent with platewide continuous GPS data away from the NMSZ, which show no motion within uncertainties. Both these data and the frequency-magnitude relation for seismicity imply that had the largest shocks in the series of earthquakes that occurred in 1811 and 1812 been magnitude 8, their recurrence interval should well exceed 2500 years, longer than has been assumed. Alternatively, the largest 1811 and 1812 earthquakes and those in the paleoseismic record may have been much smaller than typically assumed. Hence, the hazard posed by great earthquakes in the NMSZ appears to be overestimated.

Space geodetic observations of nazca-south america convergence across the central andes

Space geodetic data recorded rates and directions of motion across the convergent boundary zone between the oceanic Nazca and continental South American plates in Peru and Bolivia. Roughly half of the overall convergence, about 30 to 40 millimeters per year, accumulated on the locked plate interface and can be released in future earthquakes. About 10 to 15 millimeters per year of crustal shortening occurred inland at the sub-Andean foreland fold and thrust belt, indicating that the Andes are continuing to build. Little (5 to 10 millimeters per year) along-trench motion of coastal forearc slivers was observed, despite the oblique convergence.

Transient loss of dopamine autoreceptor control in the presence of highly potent dopamine agonists

The concentrations of endogenous ligands generally remain in a bounded range around a basal level, a manifestation of control. The dopaminergic system is an excellent example of a control system in which a negative feedback signal is associated with receptor occupancy of a D2-like dopamine autoreceptor. A consequence of the control theory is that autoreceptor occupancy by an agonist results in dopamine levels below the basal, whereas similar stimulation by a dopamine competitive antagonist results in an increase of dopamine to levels above the basal. These consequences of control theory were tested and verified in the rat striatum by infusing graded doses of either the agonist, quinpirole, or the antagonist, sulpiride, into the rat striatum via a microdialysis probe and sampling dopamine and metabolite levels at various times after the start of infusion. Control was maintained even at the very highest doses of these compounds, i.e., striatal dopamine concentration rose in response to the antagonist and fell in response to the agonist. In contrast, administration of each of two high affinity dopamine agonists, 7-OH-DPAT and PPHT showed dose-dependent control only up to certain doses. Above these doses the dopamine concentration actually increased to levels well above basal, an indication of loss of control. These findings suggest that the control of this endogenous ligand does not extend to the very highest levels of autoreceptor occupancy.

Interaction of echicetin with a high affinity thrombin binding site on platelet glycoprotein GPIb

Echicetin, a protein isolated from Echis carinatus snake venom, inhibited platelet aggregation and secretion induced by low concentrations of thrombin ( < 0.2 U/ml), by binding to platelet glycoprotein Ib (GPIb). The inhibition was not observed when the platelets were stimulated with higher concentrations of thrombin ( > 0.2 U/ml). Echicetin competed with thrombin for binding to the high affinity site on GPIb. Thrombin also inhibited 50% of the binding of 125I-echicetin to the platelets.

The relationship between vessel wall tension and the magnitude and frequency of oscillation in rat aorta

Aortic rings from adult normotensive rats display spontaneous rhythmic activity that is enhanced by vasoconstricting agents. Graded doses of norepinephrine as well as combinations of norepinephrine and vasodilators produced levels of tension that were inversely related to the magnitude of oscillation and directly related to the frequency. A similar result occurred with KCl stimulation. Oscillations were only slightly affected by removal of the endothelium. These results, when combined with other reported studies, suggest that the oscillations in rat aorta are a manifestation of feedback control that may involve the cyclic release of one or more agents affecting calcium channels.