953 research outputs found
Effects of pH on Growth of Salvinia molesta Mitchell
Growth of giant salvinia (
Salvinia molesta
Mitchell) under
different pH regimes was examined at the Lewisville Aquatic
Ecosystem Research Facility (LAERF) in Lewisville, Texas.(PDF has 5 pages.
METABOLISM OF PHENCYCLIDINE BY HUMAN LIVER MICROSOMES
ABSTRACT: These studies examined in vitro metabolism of phencyclidine (PCP) in a series of human liver microsomes (N ؍ 10). Each sample was characterized for cytochrome P 450 (CYP) content and for CYP1A, CYP2A, CYP2C, CYP2D, CYP2E, CYP3A, CYP4A, and lauric acid 11-hydroxylation metabolic activities. At least five PCP metabolites (c-PPC, t-PPC, PCHP, an unknown metabolite, and an irreversibly bound metabolite) were formed by the various human liver microsomes. Nevertheless, there was a large degree of interindividual variation in the metabolite formation. For example, the irreversibly bound metabolite was formed in detectable amounts in only four of the ten samples. c-PPC, t-PPC and the irreversibly bound PCP metabolite formation rates significantly correlated with CYP3A activity. The CYP3A inhibitor troleandomycin was used to inhibit the formation of PCP metabolites. Troleandomycin inhibition was dose dependent with the highest dose producing complete inhibition of the formation of c-PPC, t-PPC, PCHP, and the irreversibly bound metabolite. In addition, PCP inhibited CYP3A-mediated testosterone 6-hydroxylation by 50%. Furthermore, the relative intensity of CYP3A immunoreactive proteins significantly correlated with testosterone 6-hydroxylation and with PCP metabolite formation (except for the unknown metabolite). PCHP formation also correlated with CYP1A activity, while the formation of the unknown PCP metabolite correlated with CYP2A activity. These studies suggest that several CYP isoforms contribute to PCP metabolism and that CYP3A plays a major role in PCP biotransformation in human liver microsomes. Phencyclidine (PCP) 2 was originally developed by Parke-Davis in the mid-1950's for use as an anesthetic in humans but because of significant side effects it was never sold for human use. Nevertheless, in the 1960's and 1970's it became a popular drug of abuse. In addition to its anesthetic and analgesic effects in humans, PCP is known to produce a dose-dependent psychosis that resembles schizophrenia with behavior described as extremely agitated, bizarre, unpredictable, and paranoid (1-3). There is also a long-lasting PCPinduced psychosis that appears to be an idiosyncratic reaction to which only certain individuals are susceptible (1, 3). The cause of this PCP-induced psychosis is unknown, but changes in the affinity or density of PCP and dopamine receptors (4), autoimmune mechanisms (5, 6) and differences in PCP metabolism and/or PCP metabolite irreversible binding to critical neurological macromolecules Cook et al. have shown that the elimination t 1/2 of PCP varies considerably in humans, ranging from 7 to 57 hr (9 -11). The observed values in t 1/2 show a bimodal distribution. Although the majority of individuals have an average elimination of t 1/2 ϳ17 hr, 2 of the 16 individuals in these studies had t 1/2 values greater than 50 hr (11). These data suggest differences in PCP metabolism could help explain individual variations in PCP response and the reason for long-lasting effects in some individuals. Oxidation by cytochrome P 450 (CYP) enzymes is an important determinant in the overall clearance of many drugs, and differences in the CYP metabolic capabilities of humans is well documented (12, 13). Indeed, deficiencies and/or increases in tissue concentrations of some CYP isoforms can lead to unexpected toxicities and/or altered pharmacological effects of various drugs and xenobiotics PCP metabolism and irreversible binding of metabolites have been studied extensively in various tissues of rat and rabbit (e.g. 16, 17); however, relatively little is known about human PCP metabolism except for the pharmacokinetic studies by Cook et al. (9
Integrated assessment of oyster reef ecosystem services: Quantifying Denitrification Rates and Nutrient Fluxes
Measurements of nutrient exchange were made in restored oyster reefs and creek sediments in 2014 and 2015 in Harris Creek, Maryland, USA. Rates of ammonium, nitrate and di-nitrogen fluxes were much higher in reef environments than in sediments, and rates of oxygen uptake reflected high inputs of biodeposits. The rate of denitrification was related to oyster biomass and oyster numbers. The shallow nature of the restoration allows light to reach the bottom and benthic microalgal photosynthesis affects the net nutrient exchange with the bottom. After several years, oyster restoration has increased denitrification in Harris Creek, though observations in mature upper Choptank restored reefs are higher. The trajectory of increase of the nutrient ecosystem services is positive and will be followed over time
Integrated assessment of oyster reef ecosystem services: Quantifying denitrification rates and nutrient fluxes
Fluxes of N2-N (denitrification), dissolved ammonium, nitrate plus nitrite, and dissolved oxygen were determined at teh 350 acre oyster restoration project at Harris Creek, Maryland. The ex situ incubation approach involved adding oyster communities to embedded trays for ~1 mo incubating the trays under dark and light conditions for 1-2 hour time courses for gas and solute sampling, adn determination of the rates of gas and solute exchange for 136 individual reef tray incubations. Reef exchange rates were compared to rates of sediment water exchange in core incubations throughout Harris Creek and in reef-adjacent environments
Comparison of methods for determining biogeochemical fluxes from a restored oyster reef
Oyster reef restoration can significantly increase benthic denitrification rates. Methods applied to measure nutrient fluxes and denitrification from oyster reefs in previous studies include incubations of sediment cores collected adjacent to oyster clumps, benthic chambers filled with intact reef segments that have undergone in situ equilibration and ex situ incubation, and cores with single oysters. However, fluxes of nutrients vary by orders of magnitude among oyster reefs and methods. This study compares two methods of measuring nutrient and metabolic fluxes on restored oyster reefs: incubations including intact segments of oyster reef and incubations containing oyster clumps without underlying sediments. Fluxes of oxygen (O-2), dissolved inorganic carbon (DIC), ammonium (NH4+), combined nitrate and nitrite (NO2/3-), di-nitrogen (N-2), and soluble reactive phosphorus (SRP) were determined in June and August in Harris Creek, a tributary of the Chesapeake Bay, Maryland, USA. Regression of fluxes measured from clumps alone against those measured from intact reef segments showed significant positive relationships for O-2, DIC, NH4+, and SRP (R-2 = 0.920, 0.61, 0.26, and 0.52, respectively). Regression of clump fluxes against the oyster tissue biomass indicates significant positive relationships for O-2 and NH4+, marginally significant and positive relationships for DIC and N-2, and no significant relationship for NO2/3- or SRP. Although these results demonstrate that the incubation of oyster clumps without underlying sediments does not accurately represent biogeochemical fluxes measured from the whole oyster and sediment community, this work supports the need to understand the balance between the metabolism of oysters and local sediments to correctly estimate biogeochemical rates
A New Verified Compiler Backend for CakeML
We have developed and mechanically verified a new compiler backend for CakeML. Our new compiler features a sequence of intermediate languages that allows it to incrementally compile away high-level features and enables verification at the right levels of semantic detail. In this way, it resembles mainstream (unverified) compilers for strict functional languages. The compiler supports efficient curried multi-argument functions, configurable data representations, exceptions that unwind the call stack, register allocation, and more. The compiler targets several architectures: x86-64, ARMv6, ARMv8, MIPS-64, and RISC-V.
In this paper, we present the overall structure of the compiler, including its 12 intermediate languages, and explain how everything fits together. We focus particularly on the interaction between the verification of the register allocator and the garbage collector, and memory representations. The entire development has been carried out within the HOL4 theorem prover.Engineering and Physical Sciences Research Counci
Design and Performance of Odyssey IV: A Deep Ocean Hover-Capable AUV
The Odyssey IV class AUV was designed to fill the evolving needs of research and industry for a deep rated (6000 meter) vehicle, which is capable of both efficient cruising and precise hovering. This AUV is powerful enough to reject currents typical in the open ocean environment and yet small enough to be deployed from a small fishing boat. The thruster layout, two vectored side thrusters and two fixed cross-body thrusters, allow for 4-DOF control, which gives this vehicle precision and flexibility not possible in previous Odyssey class AUVs. An adaptable payload area allows the mounting of sensors, actuators, or other hardware suitable to a particular mission. The dynamic control layer of our behavior-based MOOS software was completely redesigned to take advantage of the capabilities of this vehicle. This is also the first platform to utilize new graphical controls and database-driven logging which increase operator efficiency and make the vehicle safer to operate. Odyssey IV's intended uses include survey and inspection of cold water corals, fisheries, archaeological sites, and subsea infrastructure. It will also serve as a research platform for computer vision-based servoing and acoustic supervisory control. This paper will document the design considerations and implementation of the Odyssey IV, as well as report on a series of field tests culminating in its first scientific deployment at Georges Bank, observing and mapping the invasive tunicate Didemnum.United States. National Oceanic and Atmospheric Administration (Grant NA16RG2255); United States. National Oceanic and Atmospheric Administration (Grant NA06AOR4170019
Upregulation of Mitochondrial Chaperone Proteins in Vein Grafts: A Potential Mechanism of Apoptosis-Resistance in the Arterialized Vein
An integrated biochemical prediction model of all-cause mortality in patients undergoing lower extremity bypass surgery for advanced peripheral artery disease
BackgroundPatients with advanced peripheral artery disease (PAD) have a high prevalence of cardiovascular (CV) risk factors and shortened life expectancy. However, CV risk factors poorly predict midterm (<5 years) mortality in this population. This study tested the hypothesis that baseline biochemical parameters would add clinically meaningful predictive information in patients undergoing lower extremity bypass operations.MethodsThis was a prospective cohort study of patients with clinically advanced PAD undergoing lower extremity bypass surgery. The Cox proportional hazard model was used to assess the main outcome of all-cause mortality. A clinical model was constructed with known CV risk factors, and the incremental value of the addition of clinical chemistry, lipid assessment, and a panel of 11 inflammatory parameters was investigated using the C statistic, the integrated discrimination improvement index, and Akaike information criterion.ResultsThe study monitored 225 patients for a median of 893 days (interquartile range, 539-1315 days). In this study, 50 patients (22.22%) died during the follow-up period. By life-table analysis (expressed as percent surviving ± standard error), survival at 1, 2, 3, 4, and 5 years, respectively, was 90.5% ± 1.9%, 83.4% ± 2.5%, 77.5% ± 3.1%, 71.0% ± 3.8%, and 65.3% ± 6.5%. Compared with survivors, decedents were older, diabetic, had extant coronary artery disease, and were more likely to present with critical limb ischemia as their indication for bypass surgery (P < .05). After adjustment for the above, clinical chemistry and inflammatory parameters significant (hazard ratio [95% confidence interval]) for all-cause mortality were albumin (0.43 [0.26-0.71]; P = .001), estimated glomerular filtration rate (0.98 [0.97-0.99]; P = .023), high-sensitivity C-reactive protein (hsCRP; 3.21 [1.21-8.55]; P = .019), and soluble vascular cell adhesion molecule (1.74 [1.04-2.91]; P = .034). Of the inflammatory molecules investigated, hsCRP proved most robust and representative of the integrated inflammatory response. Albumin, eGFR, and hsCRP improved the C statistic and integrated discrimination improvement index beyond that of the clinical model and produced a final C statistic of 0.82.ConclusionsA risk prediction model including traditional risk factors and parameters of inflammation, renal function, and nutrition had excellent discriminatory ability in predicting all-cause mortality in patients with clinically advanced PAD undergoing bypass surgery
Anti-(+)--methamphetamine monoclonal antibodies
Compositions and methods for effectively treating at least one symptom or sign of methamphetamine use, or for slowing the rate of (+) methamphetamine entry into the brain of a subject are described. The method comprises administering an effective amount of an anti-(+) methamphetamine antibody to a subject
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