2,596 research outputs found
N,N,N′,N′-Tetrakis(pyridin-4-yl)methanediamine monohydrate
In the title compound, C21H18N6·H2O, two 4,4′-dipyridylamine groups are linked by a methylene C atom, which sits on a twofold axis. The lattice water molecule is located slightly off a twofold axis, and is therefore disordered over two positions. In the crystal, the organic molecules and the water molecule are linked by O—H⋯N hydrogen bonds. The organic molecules exhibit extensive offset face-to-face π–π interactions to symmetry equivalents [centroid–centroid distances = 3.725 (3) and 4.059 (3) Å]
Bioremediation of Petroleum Hydrocarbons in Louisiana\u27s Saltwater Marshes: Sediment Oxygen Demand Model.
Laboratory core studies were conducted to determine sediment oxygen demand (SOD) in petroleum hydrocarbon contaminated salt marshes. Natural degradation processes in salt marshes such as aerobic respiration, nitrification and sulfate reduction were investigated to quantify SOD. Oxygen demand in oiled/fertilized cores was greater than control and fertilized cores due to increased oxygen consumption by oil degradation and oxidation of reduced chemicals; sulfide and ammonium. SOD under non-flooded condition was greater than flooded condition due to an increased area of oxic-anoxic interface during air exposure. This may indicate that significant biodegradation of crude oil only occurs when the surface of the salt marsh is exposed to the atmosphere. Simultaneous measurements of total CO2 production and 35SO4 2- reduction were performed to partition carbon flow pathways between aerobic respiration and sulfate reduction in crude oil contaminated salt marsh sediment. Crude oil and fertilizer stimulated sulfate reduction rates and highest sulfate reduction rates were observed in the top 2-cm depth. Sulfate reduction was a major sink of oxygen demand. Mineralization kinetics of 14C-hexadecane and -phenanthrene were determined from core studies. The obtained zero-order rate constants at different level of nitrogen loading rates indicate that biodegradation of crude oil was enhanced when ammonia nitrogen concentration in pore water was maintained above 200 ppm. A SOD model was successfully applied to estimate SOD in oil contaminated salt marshes. Carbonaceous and nitrogenous sediment oxygen demand models were calibrated through a non-linear regression technique. Oil sediment oxygen demand (OSOD) model which simulates oxygen uptake, cell growth and oil degradation simultaneously was solved numerically and compared with experimental data. Field study was conducted to measure sediment oxygen demand, sulfate reduction and oil sediment oxygen demand over six months. SOD (flooded and non-flooded) in control, oiled, and oiled/fertilized (ammonia nitrate treated) salt marsh soils was measured. Higher SOD under oiled and oiled/fertilized conditions indicates that aerobic biodegradation of crude oil is occurring and thus increasing O2 demand. Although sulfate reduction consumes a significant amount of oxygen demand, major portion of the demand is caused by aerobic respiration due to crude oil degradation
Acetonitrile{3-[bis(2-pyridylmethyl-κN)amino-κN]propanol-κO}(perchlorato-κO)copper(II) perchlorate
In the title compound, [Cu(ClO4)(C2H3N)(C15H19N3O)]ClO4, the CuII ion is coordinated by three N atoms and a hydroxyl-O atom of the tetradentate ligand, an O atom of a perchlorate ion and an N atom of an acetonitrile ligand giving a tetragonally distorted octahedral environment around the copper(II) atom. There is an offset inter-complex face-to-face π–π interaction [centroid–centroid distance = 3.718 (2) Å] involving one of the pyridine rings of the ligand as well as an intra-complex O—H⋯O hydrogen-bonding interaction between the coordinated hydroxyl group of the ligand and the perchlorate counter-ion
The effect of phenylephrine on the onset time of rocuronium
BACKGROUND: Several studies have demonstrated that ephedrine shortens the onset time of muscle relaxants, and it does so probably by increasing the cardiac output. However, elevation of the systemic blood pressure through α adrenergic stimulation via ephedrine may affect the onset of muscle relaxants during the induction of anesthesia. We investigated the effect of phenylephrine, which is a selective α-1 agonist, on the onset time of rocuronium and the intubating conditions in adults after the administration of propofol.
METHODS: Sixty-four patients were randomly assigned to two groups. Phenylephrine (0.9 µg/kg) (P group) or the same volume of saline (S group) was injected before rocuronium (0.6 mg/kg) administration. Anesthesia was induced with fentanyl 2 µg/kg and propofol 2 mg/kg. The onset time was defined as the time from the end of rocuronium injection to the time when a single twitch height gets to 0% or the minimum level. A well-trained anesthesiologist who was 'blinded' to the treatment groups evaluated the intubating conditions. The mean arterial pressure and heart rate were recorded before induction, before intubation, immediately after intubation and 1 minute and 2 minutes after intubation.
RESULTS: The onset time was 84 ± 18 sec in the P-group and 72 ± 14 sec in the S-group. There was no difference of the intubating conditions, the mean arterial pressure and the heart rate between the two groups.
CONCLUSIONS: A small dose of phenylephrine, which has a limited effect on blood pressure, delayed the onset time of rocuronium after the administration of propofol, and the vasoconstriction effect of phenylephrine may affect the prolongation of the rocuronium onset time at the induction of anesthesia with using propofol.ope
Clinical Characteristics of Monomorphic Post-transplant Lymphoproliferative Disorders
Post-transplant lymphoproliferative disorders (PTLD) are a heterogeneous group of lymphoproliferative disorders associated with immunosuppression and Epstein-Barr virus infection. PTLD is classified into three major categories: early lesions, polymorphic PTLD, and monomorphic PTLD. The majority of monomorphic PTLD cases are non-Hodgkin's lymphoma of B-cell origin. This retrospective study was conducted to investigate the incidence, clinical manifestation, treatment, and outcomes of monomorphic PTLD among 5,817 recipients of solid organ or allogeneic hematopoietic stem cell transplantation from five institutions. Fourteen patients with monomorphic PTLD were identified (male:female 11:3; median age 42.6 yr, range 24-60). The overall incidence rate was 0.24%. The most common disease type was diffuse large B cell lymphoma (n=7). The median time between the transplant and diagnosis of PTLD was 85.8 months. However, all cases of PTLD after allogeneic hematopoietic stem cell transplantation occurred within 1 yr after transplantation. Ten of the 14 patients had EBV-positive tumor. Fourteen patients received combination systemic chemotherapy and four patients were treated with radiation therapy. Ten patients achieved a complete response (CR) and two patients a partial response (PR). The median follow-up period for surviving patients was 36.6 months. Nine patients remain alive (eight CR, one PR). Nine of 11 solid organ transplantations preserved graft function. The present study indicates a lower incidence rate and a longer median time before the development of PTLD than those of previous reports. Careful monitoring was needed after allogeneic hematopoietic stem cell transplantation for PTLD
Quantitative measurements of C-reactive protein using silicon nanowire arrays
A silicon nanowire-based sensor for biological application showed highly desirable electrical responses to either pH changes or receptor-ligand interactions such as protein disease markers, viruses, and DNA hybridization. Furthermore, because the silicon nanowire can display results in real-time, it may possess superior characteristics for biosensing than those demonstrated in previously studied methods. However, despite its promising potential and advantages, certain process-related limitations of the device, due to its size and material characteristics, need to be addressed. In this article, we suggest possible solutions. We fabricated silicon nanowire using a top-down and low cost micromachining method, and evaluate the sensing of molecules after transfer and surface modifications. Our newly designed method can be used to attach highly ordered nanowires to various substrates, to form a nanowire array device, which needs to follow a series of repetitive steps in conventional fabrication technology based on a vapor-liquid-solid (VLS) method. For evaluation, we demonstrated that our newly fabricated silicon nanowire arrays could detect pH changes as well as streptavidin-biotin binding events. As well as the initial proof-of-principle studies, C-reactive protein binding was measured: electrical signals were changed in a linear fashion with the concentration (1 fM to 1 nM) in PBS containing 1.37 mM of salts. Finally, to address the effects of Debye length, silicon nanowires coupled with antigen proteins underwent electrical signal changes as the salt concentration changed
WSPMaker: a web tool for calculating selection pressure in proteins and domains using window-sliding
Cultural Practices to Reduce Cd Content in Edible Parts of Staple Crops in Korea
Objectives of this study were to determine the uptake and translocation of Cd in rice plant from soil with applying the water management and soil ameliorators and to investigate the correlations among heavy metal contents in the brown rice, soil pH and chemical species of Cd existing in soil by sequential extracting method with paddy soil contaminated with Cd near abandoned mine. To identify the effect of soil ameliorators on Cd uptake in rice plants, compost and lime were treated. Plants were grown with irrigation water concentrated by 0.01mg kg^ of cadmium in two soil types (sandy loam and clay loam) with treatments of intermittent irrigation and continuous submersion conditions. Compared to intermittent irrigation plots, average Eh value in the continuous submersion plots was low at 136.7mV whereas pH value was high at 0.3. Eh value was decreased in the treatment of soil ameliorator while pH value was increased by 0.2~0.3. Cd content of leaves and brown rice had significantly positive correlation with Eh value in soils while was negatively correlated with soil pH. At the harvest stage, Cd content in the leaves and brown rice was decreased in the continuous submersion plots by 30% relative to the intermittent irrigation plots. In case of soil ameliorator applied plots, Cd content of leaves and brown rice was lower by 35% than that of N, P, K fertilizer plots, respectively. Compared to the soil types, Cd content of leaves and brown rice in sandy loam soil was lower by 64 and 37% than that in clay loam soil, respectively. Order of reduction to Cd uptake was the compost and lime mixture plot>silicate plot>lime plot. However, the effect of Cd uptake reduction by soil ameliorator was decreased in the N, P, K+compost and N, P, K+phosphate plots. Cd uptake reduction by water management and soil ameliorator was more effective in the sandy loam soil than that in the clay loam soil.Special Revie
trans-Diazido(1,8-dibenzyl-1,3,6,8,10,13-hexaazacyclotetradecane)nickel(II)
In the centrosymmetric title compound, [Ni(N3)2(C22H34N6)], the NiII ion is coordinated by the four secondary N atoms of the macrocyclic ligand in a square-planar fashion with two N atoms of the azide ions in axial positions, resulting in a tetragonally distorted octahedron. An N—H⋯N hydrogen-bonding interaction between the secondary amine N atom of the macrocycle and an adjacent azide ion gives rise to a chain structure
trans-{1,8-Bis[(R)-α-methylbenzyl]-1,3,6,8,10,13-hexaazacyclotetradecane}dithiocyanatonickel(II)
The title compound, [Ni(NCS)2(C24H38N6)], is a thiocyanate-coordinated azamacrocyclic nickel(II) complex. There are two independent molecules in the asymmetric unit and their bond lengths and angles are similar. Both Ni atoms have a tetragonally distorted octahedral geometry, in which the NiII ion is coordinated by the four secondary N atoms of the azamacrocyclic ligand and by two N atoms of the thiocyanate ions. The average equatorial Ni—N bond lengths are shorter than the average axial Ni—N bond lengths [2.071 (1) and 2.115 (2) Å, respectively]. N—H⋯S hydrogen-bonding interactions between a secondary amine N atom and the adjacent thiocyanate ion leads to a polymeric chain along [100]
- …