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Rho kinase (ROCK) inhibitors are potential therapeutic agents for the treatment of a variety of disorders including hypertension, glaucoma and erectile dysfunction. Here we disclose a series of potent and selective ROCK inhibitors based on a substituted 7-azaindole scaffold. Substitution of the 3-position of 7-azaindole led to compounds such as 37, which possess excellent ROCK inhibitory potency and high selectivity against the closely related kinase PKA.

Differing responses to abiotic stresses and increased nutrient availability may play a role in the invasion and spread of introduced Phragmites australis Cav. (Trin.) ex. Steud. and the decline of native P.a. americanus Saltonstall, P.M. Peterson & Soreng in North America. We present results from an outdoor experiment where native and introduced P. australis seedlings were grown under two nutrient treatments. Both subspecies responded positively to increased nutrients but introduced plants clearly outperformed natives, growing taller, producing more stems, and had three to four times higher biomass. The biomass of introduced P. australis growing in low nutrients was similar to that of the native in high nutrients. Aboveground:belowground biomass ratios were nearly 1.25 for both native and introduced plants across treatments and reflect the high investment P. australis seedlings place on shoot production in their first year of growth. Our results also demonstrate that introduced P. australis can have explosive growth over a single growing season, even when established from seed. This implies that management of young, newly established populations may be prudent where introduced P. australis is considered undesirable, irregardless of whether eutrophication is an issue.

We constructed a numerical simulation model of an enclosed, submersed macrophyte ecosystem to examine the effects of nutrient supply rates, grazer densities and initial conditions on macrophytes and epiphytic algae. The model included an internal, non-structural plant nutrient pool that controlled root and leaf nutrient uptake and was calibrated to literature values and mesocosm experiments. Simulations were run to examine how initial conditions, nutrient supply rates and the presence of grazers may affect macrophyte–algal competition experiments. Simulations revealed that the outcome of an experiment could be largely controlled by the initial conditions or by biomass changes during the experiment. For example, high initial macrophyte biomass reduced light and nutrients available for algae, which prevented the overgrowth of algae, even at high nutrient addition rates. Epiphytic algae biomass increased with water exchange rate regardless of inflow nutrient concentration. Submersed plants grew best at lower exchange rates that allowed nutrient concentrations to be drawn down, slowing algal growth. Simulations showed that the effect of grazers on epiphyte biomass was greatest at intermediate nutrient addition rates. When grazers were absent, macrophyte biomass could be highest with low or high inflow nutrient concentrations, depending on the exchange rate. Model analysis also revealed that it is essential to consider nutrient loading rate per unit macrophyte biomass, not just nutrient concentration, when quantifying the effects of eutrophication on submersed macrophytes in shallow water. These results show the utility of using a simulation model together with ecosystem experiments. They also show how water exchange rates, which can depend on bed size, could affect eutrophication responses of submersed macrophyte ecosystems.

We recently described the identification of an optimized α-ketoamide warhead for our series of HCV NS3·4A inhibitors. We report herein a series of HCV protease inhibitors incorporating 3-alkyl-substituted prolines in P2. These compounds show exceptional enzymatic and cellular potency given their relatively small size. The marked enhancement of activity of these 3-substituted proline derivatives relative to previously reported 4-hydroxyproline derivatives constitutes additional evidence for the importance of the S2 binding pocket as the defining pharmacophore for inhibition of the NS3·4A enzyme.

The α-ketoamide warhead (e.g., 15) was found to be a practical replacement for aliphatic aldehydes in a series of HCV NS3·4A protease inhibitors. Structure–activity relationships and prime side optimization are discussed.

A set of HIV protease inhibitors represented by compound 2 has previously been described. Structural and conformational analysis of this compound suggested that conformational restriction of the P1/P2 portion of the molecule could lead to a novel set of potent protease inhibitors. Thus, probe compounds 3-7 were designed, synthesized, and found to be potent inhibitors of HIV protease.

A combination of structure-based design and both solution, and solid-phase synthesis were utilized to derive a potent (nM) series of HIV-1 protease inhibitors bearing a structurally novel backbone. Detailed structural analysis of several inhibitors prepared in this series has suggested that rigidification of the P1/P2 region of this class of molecules may result in compounds with improved potency.

Major processes controlling sedimentological characteristics and accretionary rates and patterns were evaluated in two of the most common tidal marsh settings (estuarine tributaries and estuarine embayments) in Chesapeake Bay, one of the largest microtidal estuaries in the world. Textural analyses of 29 vibracores show spatial and temporal trends in grain size and organic matter which reflect differences in depositional settings within the marshes and changes in the controlling processes, as well as broader events in the surrounding watersheds. Spatially, the surficial sediments normally follow expected patterns, with coarsest sediments and lowest organic matter contents found in bay margin or channel margin locations, while the finest, organic-rich sediments occur in interior and submerged upland marshes. However, temporally, the marshes do not always show the expected increasing dominance of organic input over time (indicated by increasing % loss on ignition with decreasing depth), indicative of the marsh building process. Sea-level rise, tidal channel migrations, and anthropogenic effects likely contribute to decreases in organic matter contents in the upper sediment column. Furthermore, accretion rates and stratigraphic characteristics can be affected by these same processes, illustrating the importance of understanding temporal changes in marsh depositional environments over various time scales before sedimentologic and accretionary patterns are evaluated. Examination of the vibracores reveals that the marsh is composed of a complex stratigraphy with at least four major stratigraphic sequences occurring: (1) emerging or developing marsh sequences characteristic of channel margin and interior marshes; (2) submerging or mineral matter enriched marshes, also characteristic of channel and interior marsh areas; (3) high-energy marsh sequences characteristic of bay margin environments; and (4) submerged upland marsh sequences. The sedimentological properties of the stratigraphic sequences are controlled by overwash processes, tidal channel migrations, duration of tidal flooding, various anthropogenic effects, and sea-level rise. Accretion rates and patterns over the last ∼200 years, determined from pollen histories, differ between the marshes along the estuarine tributary (Nanticoke River) and those found in the tidal embayment (Monie Bay). Marshes in the upper-estuarine tributary have a larger riverine sediment input, and trapping of the high sediment loads in the upper estuary often yields marsh accretion rates (maximum of 0.74 cm/yr) which are greater than relative sea-level rise (∼0.4 cm/yr), resulting in stable marshes. By comparison, estuarine processes limit penetration of high sediment loads to the lower reaches of marshes along the tributary and, as a consequence, accretion rates are generally lower than the rate of relative sea-level rise, and marsh loss is prevalent. Overall, accretion rates in the marshes in the embayment are close to or less than the local sea-level rise and do not have as distinctive spatial patterns as the tributary marshes. Although marsh loss has yet to be identified as a significant process here, decreases in organic content of the upper sediment column may signal the early stages of submergence due to sea-level rise.

Porewater phosphate levels in submersed macrophyte grassbeds varied among years in the upper Chesapeake Bay (Maryland, USA) coincident with macrophyte species variation during these same years (1990, 1993, 1995). When native, deep-rooted Vallisneria americana Michx. was a codominant in the grassbed, the porewater phosphate concentrations were significantly lower (P < 0.001) than concentrations when the exotic, shallow-rooted species Hydrilla verticillata (L.f.) Royle and Myriophyllum spicatum L. were codominants. There were significant relationships (P < 0.001) between solid-phase inorganic phosphorus and reactive metals (Fe, Mn) in both native and exotic grassbeds. However, the slopes of the regression relationships between years were significantly different (P < 0.001), suggesting greater retention of inorganic phosphorus in sediments when V. americana was a codominant at the site. In addition, significant relationships between reactive manganese and iron in the sediments were observed, but the coefficient of determination was statistically greater (P < 0.001) when V. americana was a codominant at the site. Furthermore, plant cores of V. americana and H. verticillata had noticeably different sediment redox profiles, with the oxidation-reduction status of V. americana sediments being more oxidized in the root zone (i.e., +125 mV vs −5 mV at 4 cm depth). These data suggest that macrophyte species composition can alter sediment biogeochemistry resulting in varying porewater phosphate and solid-phase phosphorus and metal levels. Possible explanations for these biogeochemical differences may be attributed to morphological differences among macrophyte species (i.e., root/shoot ratio, canopy type, growth form) and differences in root oxygenation capabilities.

Hybrid structural analogs 1 of the PDE V and PDE III inhibitors, zaprinast, milrinone, and CI-930 were prepared to identify dual PDE inhibitors. The SAR study led unexpectedly to the identification of WIN 61691 (8d), a potent inhibitor of PDE I (IC50 = 85 nM). A potent and selective inhibitor of PDE I would be a useful tool to elucidate the physiologic function of PDE I and other PDE isozymes in biological systems.

Distinct differences in the SAR for HLE and PPE inhibition in this class of compounds were observed. For example, larger lipophilic substituents at the benzisothiazolone 4-position afforded inhibitors that were potent against HLE, but inactive against PPE. These findings are consistent with computer models of inhibitor-enzyme complexes built using the X-ray structure coordinates of HLE and PPE. These models show that substituents at the benzisothiazolone 4-position fit into the S1 specificity pocket of the enzyme and that other differences in the SAR can be explained based on the structural differences of HLE and PPE.

Directed lithiation of substituted 2- n -alkyl N,N -diethylbenzamides gave mixtures of ortho and adjacent-benzylic alkylated products ( 2 and 3 ). The ratios of isolated products were dependent upon the substitution patterns of the benzene ring and on the reaction conditions. Substrates and reaction conditions that favor either ortho or adjacent-benzylic lithiation are presented.

The hydrogenation of acetone was investigated in basic aqueous solutions with undoped and chromium-doped catalysts. The reaction was carried out under pressure in an autoclave equipped with a reference electrode. The consumption of hydrogen and the electrode potential were measured during the course of the reaction. A mathematical model was applied which fits the experimental kinetic data well. It allows the computation of the rate constant and the adsorption equilibrium constants. The kinetics obey a Langmuir-Hinshelwood mechanism with competitive adsorption. The metallic catalyst particles behave like a dispersed electrode and an electrochemical double layer is formed at their surface. In the presence of hydrogen alone, the metal potential obeys the Nernst law for the hydrogen electrode. During acetone hydrogenation, the double layer is modified and the measured potential goes to the positive region for several tens of millivolts, depending on whether the catalyst is doped or not. In all cases an experimental correlation was found between this experimental potential rise and the reaction rate.

The lead compound for this SAR study, benzisothiazolone 1a, was a 15 nM inhibitor of HLE, but was unstable in human blood ( t 1 2 min). The introduction of lipophilic substituents at the R4-position such as ethyl or isopropyl and modulation of the electrophilicity of the benzisothiazolone carbonyl led to the identification of a potent ( K i ∗ =0.27 nM) and blood stable ( t 1 2 =260 min) inhibitor 2e, WIN 63395.

A new type of mechanism-based inhibitor of human leukocyte elastase (HLE) is described that are designed to inhibit HLE by a suicide route to form an inhibitor-enzyme complex by cross linking the enzyme active site. A mechanism of HLE inhibition is proposed and was used to design analogues with improved potency. The structure-activity relationships described in this paper are consistent with the proposed mechanism of HLE inhibition, and led to WIN 62785 ( 12 ), the most potent compound in this series with a K i * = 0.3 nM.

The introduced submersed aquatic plant, Hydrilla verticillata, is currently spreading in the Chesapeake Bay, and is colonizing previously unvegetated areas and displacing native flora. To examine the effects of this invasion, we compared faunal densities between Hydrilla beds and unvegetated sand areas. Transplants of Hydrilla and sampling from natural Hydrilla and unvegetated patches indicate that this plant enhances the abundances of a variety of benthic fauna. Among two clam species transplanted into Hydrilla patches and adjacent unvegetated areas, one demonstrated enhanced survival within Hydrilla patches while the other exhibited reduced tissue growth. Similarly, the growth form of Hydrilla may have been affected by clam presence. Dissolved oxygen, sediment characteristics, and sediment resuspension also varied between Hydrilla and unvegetated areas. The spread of Hydrilla in the Chesapeake Bay clearly has significant, though complex, effects on the bottom community. Such effects emphasize the potential importance of introduced plants in altering community characteristics.

The readily available N,N-diethylbenzamides 2 are converted in two reaction steps to a variety of substituted saccharins 4 in good overall yields.

Although the concept that marshes act as major sediment sinks may be accurate when viewing them over the last few millennia, tidal transport studies suggest considerable variability with most marshes presently exporting material on an annual basis. High-salinity marshes along the mid-Atlantic coast of the United States appear to be losing 1–2 kg m−2 yr−1 while submerged upland marshes on the Delmarva Peninsula are eroding at rates of up to 14 kg m−2 yr−1. By comparison, at least one deltaic marsh on the Dutch coast along with several estuarine marshes appear to be accumulating sediment. In order to assess the trapping ability of marshes in large estuaries, we constructed a sediment budget for Chesapeake Bay which included a variety of wetland types. Calculations indicate that estuarine marshes trap 5–11% of the annual Chesapeake Bay sediment input, or about one half that previously estimated. It appears that most sedimentation in estuaries, and perhaps other coastal systems, occurs in subtidal flats below the limit of emergent marsh vegetation. As mud flats become vegetated and estuarine infilling proceeds, there may be a tendency for tidal currents to become ebb-dominated which promotes a net export of particulates. The extent to which major storm events are capable of returning enough material to balance the long-term accretionary budget of tidal marshes and keep them abreast of rising sea level is open to question. Differences in tidal dynamics, seasonal changes in sea levels and higher temperatures may help explain why, in the U.S., southern marshes are more susceptible to export and eventual erosion than northern marshes. We hypothesize that another factor, the recent reductions of terrigenous sediment inputs from the southern river systems of the U.S., may also be critical. Sediment starvation may have led to undernourishment of wetland systems of the coastal zone over the last half century which may be reflected in the net export measured in the tidal marshes in this region. Furthermore, we postulate that changes in sediment inputs are more important than eustatic sea level rise in causing the past losses of marshes which are now undergoing mass erosion. Thus, future wetland survival will depend as much as particulate inputs to the coastal zone as on the prospects of a global rise in sea level, and more efforts should be made to quantify the sediment budgets of tidal marshes.

The decomposition kinetics of benzoyl peroxide in 4-carbomethoxy-pyridine and in 4-carbomethoxy-pyridine/benzene have been studied in the presence and absence of inhibitor. The rate constant, for the radical induced decomposition of benzoyl peroxide was 2.6×10-4 1 mol-1 s-1 in 4-carbomethoxy-pyridine, and in benzene it was 9.2×10-6 1 mo1-1 s-1 , a thirty fold decrease. A mechanism including the attack at the nitrogen atom of the pyridine ring by the phenyl radical and the oxidation of the sigma-complex by the 1-phenyl-4-carbomethoxy pyridinium ion has been proposed. The system of the differential equations obtained from the proposed mechanism has been numerically solved.

Fetal cardiorespiratory changes during spontaneous prelabor uterine contractions (called contractures) were studied in 12 chronically catheterized fetal sheep at 120 to 143 days' gestation. During contractures the carcass blood flow increased significantly from 27 +/- 2 (SEM) to 32 +/- 3 ml/min/100 gm. There were no significant changes in combined ventricular output or in blood flow to the umbilical circulation, brain, heart, adrenal glands, gut, kidney, and lung. Fetal arterial blood pressure increased from 57 +/- 2 to 62 +/- 1 mm Hg (p less than 0.001) during contractions. There were no significant changes in fetal heart rate. In the fetal femoral artery during contractures the oxygen content decreased from 6.1 +/- 0.2 to 5.4 +/- 0.2 ml/dl of blood (p less than 0.001), and carbon dioxide tension increased significantly from 44 +/- 0.4 to 45 +/- 0.4 mm Hg (p less than 0.001). The pH did not change. The increase in carcass blood flow during contractures suggests that there was an increase in fetal skeletal muscular activity or tone. An increase in fetal skeletal muscle activity, together with a decrease in uterine blood flow could explain the small decrease in fetal oxygen content that occurs with each contracture. Fetal compression and/or changes from rapid eye movement to synchronized sleep or arousal observed during contractures are possible stimuli causing increased fetal skeletal muscle tone or activity. Since contractures periodically result in neuromuscular activity in the fetus in its protected fluid-filled environment, they may play a key role in fetal neuromuscular development by stimulating "exercising" in the fetus in utero.

Resume Nous avons etudie l'influence d'un substituant en position 4 de la pyridine sur la cinetique de decomposition du peroxyde de benzoyle dans les molanges benzene(X-4 pyridine (X = CH3, H, CN). La constante de vitesse du 2eme ordre de la decomposition induite nucleophile passe de 2x10-6lmol-1s-1pour la pyridine a 1 x10-5 l mol-1s-1 pour la methyl-4 pyridine, alors que la cyano-4 pyridine n'attaque pas les atomes d'oxygene peroxydiques du peroxyde de benzoyle. Nous pensons que l'augmentation ties importante de la decomposition induite radicalaire observee avec la cyano-4 pyridine peut-tre attribuee a 1'attaque de l'azote pyridinique par les radicaux phenyle, le radical phenyl-l pyridinyle etant stabilise par le groupe cyano.

Characteristics of sediment transport and deposition were studied in a Maryland brackish marsh system which has experienced extensive erosion (2300 ha) over the last four decades. Ebb-tide domination of the marsh system contributes to a net output of 720,000 MT of sediment per year (13.8 kg m−2 yr−1). This export allows very little inorganic sediment to reach the interior marsh despite the sporadic high concentrations of total suspended solids in the tidal channels (10–1400 mg l−1). Vertical accretion in these marshes is primarily by peat deposition instead of the accumulation of mineral sediment. 210Pb dating suggests that accretion rates ranging from 1.7 to 3.6 mm yr−1 in the area of active marsh loss probably have not kept pace with sea-level rise since 1940 (3.9 mm yr−1). The reliance on organic sedimentation in the past has resulted in the development of a thin (0.1–0.5 m) consolidated marsh mat over 1–4 m of unconsolidated organic ooze. Erosion typically follows a sequence of incipient deterioration of the mat, possibly associated with heavy grazing activity by muskrats, and subsequent development of interior ponds. Once formed, the ponds slowly enlarge by undifferentiated rotational slumping. When they reach about a hectare in size they rapidly elongate in a NW-SE direction by wind-generated wave undercutting of the mat during major NW-tracking storms. Several hypotheses are presented to explain fundamental reasons why this marsh type is not accreting rapidly enough to keep abreast of apparent sea-level rise.

The rate of acetylene reduction was determined for Myriophyllum spicatum, Potamogeton perfoliatus, Ruppia maritima and Elodea canadensis , in a brackish water tributary of Chesapeake Bay. Ruppia had the highest nitrogen fixation rate on a dry weight basis [66 ng-at. N(g wt h) −1 ]. However the fixation per square meter of creek bottom was highest [16·3 μg-at. N(m 2 h) −1 ] for Myriophyllum due to its greater biomass. Generally, our low rates are more comparable to those associated with seagrasses in North Carolina, than to many higher rates reported from tropical waters. We postulate that low nitrogen fixation rates are a consequence of the availability of nitrogen either in the water column or sediments of temperate estuaries such as the Chesapeake Bay, and the North Carolina Sounds.

A proteoglycan was isolated from the red alga Laurencia spectabilis Postels & Ruprecht (Ceramiales) by extraction in a dilute buffer—NaCl solution followed by gel and anion exchange chromatography. The molecule was composed of 92% carbohydrate and 8% protein. Galactose and uronic acids were the major monosaccharides. Ester sulfate was not detected. A small quantity of hydroxyproline was present in the protein component. The proteoglycan accounted for a very small portion (less than 1% by fr. wt) of the alga.

A series of bimetallic Ni Crx and Ni Mox catalysts were prepared by co-reduction of mixtures of dry iodides of appropriate composition with sodium naphthalene as reducing agent. Observations by transmission electron microscopy (TEM) and local analyses (scanning TEM and energy-dispersive X-ray spectrometry) showed that this procedure gave finely divided homogeneous alloys. The bimetallic powders (50–200A) developed a large BET surface area (100–170 m2g−1). Auger spectra showed that chromium was strongly segregated on the surface in an oxidized state, whereas molybdenum was metallic and no segregation was observed. The turnover number (TON) of cyclohexene hydrogenation did not depend on the nature of the promoter or on the composition (TON=0.28±0.2 s−1). For acetophenone hydrogenation, Ni Crx catalysts exhibited catalytic activity greater than commercial Raney nickel; the initial rate on Ni Cr0.12 was ten times greater. In addition to their great activity, Ni Crx catalysts showed better selectivity, the yield of 1-phenylethanol being as high as 95%. Ni Mox catalysts were approximately as reactive as commercial Raney nickel, with an increase in the rate of hydrogenolysis of the C OH bond.

A nitric acid digestion method is presented for rapid and inexpensive preparation of 14 C-labelled macrophyte tissue for liquid scintillation counting. No significant difference was found when the method was compared to combustion in oxygen. Results from time-series experiments with labelled sucrose as well as plant materials indicated little loss of labelled organics as volatile compounds over a 16 h period, and complete recovery of the label was attained.

The use of the novel reagents 1a–c for the synthesis of ketones in a one pot reaction is described. An interesting leaving group effect was discovered in the fragmentation of the proposed complexes 2 to the intermediate N-methoxyamides 3 .

Resume La reaction du cation phenyle, obtenu par decomposition thermique du tetrafluoroborate de benzenediazonium, avec le dimethyl-1,4 naphtalene en solution dans le DMSO, conduit en plus des derives phenyles en position 2,5 et 6, au methyl-1 methylene-4 phenyl-1 dihydro-1,4 naphtalene. La formation de ce compose, constitue une preuve directe de l'attaque en position ipso du methyle par le cation phenyle. En solution dans l'acetonitrile, et dans le dimethyl-1,4 naphtalene pur, la deprotonation de l'ion ipso-arenium n'est pas observee et la reaction principale est la migration 1–2 du phenyle. La reactivite de la position ipso vis-a-vis du cation phenyle est voisine de celle de la position 2. Le methyl-1 phenyl-4 naphtalene n'a pas ete detecte par C.P.G., la phenyldemethylation du dimethyl-1,4 naphtalene est donc negligeable.

Measures of oxygenation in the chronically prepared fetus have shown considerable variation when reported by different investigators despite apparent physiological ‘resting’ conditions. This variation has been compounded by differences in the blood vessels sampled and varying accuracy of biochemical methodology, so was consequently assumed to reflect methodological error and variability. However, development of continuously recording systems for oxygen pressure and hemoglobin saturation has confirmed the continuously varying values of oxygenation. It is the purpose of this review to examine the biological causes and associations of the variations in basal oxygenation.

Resume La reaction du cation phnyl obtenu par decomposition thermique du ttrafluoroborate de benzene diazonium avec le chloro-4 anisole conduit en plus des derives phenyles en position 2 et 3 au chloro-2 methoxy-4 biphenyle. Ce compose resulte de l'attaque de C6H5+ en position ipso du chlore suivie de la migration 1–2 de l'halogene. Cette reaction de rearrangement importante en milieu heterogene est totalement anihilee dans un solvant nucleophile comme le dimethylsulfoxide. La capacite du DMSO a pieger lesions ipso-arenium a permis la mise en evidence indirecte de l'attaque en position ipso du methoxy. La migration 1–2 du phenyle a ete observee pour les ions resultant de l'attaque en ipso du chlore et du methoxy. On n'a pas detecte par C P G de phenyl-4 anisole ni de dichloro-2,4 anisole, la phenyldechloration du chloro-4 anisole est done negligeable.

A microcomputer-based system has been developed to measure oxygen consumption continuously in fetal sheep. The system includes an umbilical artery electromagnetic blood flow transducer and two fiberoptic catheter oximeters for measuring umbilical artery and vein oxyhemoglobin saturation in vivo. The electrical signals from these instruments are digitized and sampled by a microcomputer. Fetal oxygen consumption is calculated from the Fick principle by use of the digitized signals and hemoglobin concentrations. The latter is measured intermittently and updated if necessary. System validation required that artifacts in oxyhemoglobin recordings could be avoided and that the catheter readings agreed with values from intermittent samples. Continuous heparin infusion and careful catheter placement facilitated attainment of these requirements. The system can be used to obtain continuous recordings of fetal oxygen consumption during rapidly occurring physiologic events.