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Asparaginase is an important drug to treat childhood haematological malignancies. Data on the association between human leukocyte antigens (HLA) and asparaginase hypersensitivity among Chinese are lacking. We conducted a retrospective study to identify HLA alleles associated with asparaginase hypersensitivity among Chinese children with acute lymphoblastic leukaemia (ALL), mixed phenotype leukaemia and non-Hodgkin lymphoma (NHL), who received asparaginases with HLA typing performed between 2009 and 2019. 107 Chinese patients were analysed. 66.3% (71/107) developed hypersensitivity to at least one of the asparaginases. HLA-B*46:01 (OR 3.8, 95% CI 1.4–10.1, p p l-asparaginase hypersensitivities, which remained significant after adjustment for age, gender and B cell ALL [HLA-B*46:01 (adjusted OR 3.5, 95% 1.3–10.5, p = 0.02) and DRB1*09:01 (OR 4.4, 95% CI 1.6–13.3, p

The azinomycins are a family of aziridine-containing antitumor antibiotics and represent a treasure trove of biosynthetic reactions. The formation of the azabicyclo[3.1.0]hexane ring and functionalization of this ring system remain the least understood aspects of the pathway. This study reports the incorporation of 18O-labeled molecular oxygen in azinomycin biosynthesis including both oxygens of the diol that ultimately adorn the aziridino[1,2- a]pyrrolidine moiety. Likewise, two other sites of heavy atom incorporation are observed.

Total mercury (THg) and methylmercury (MeHg) were recorded in the commercial demersal fish Lethrinus nebulosus, caught from six locations in Qatar EEZ (Exclusive Economic Zone). Concentrations of THg decreased in the order: liver ˃ muscle ˃ gonad. THg concentrations in fish tissue ranged from 0.016 ppm in gonad to 0.855 ppm (mg kg−1 w/w) in liver tissues, while concentrations in muscle tissue ranged from 0.24 to 0.49 ppm (mg kg−1 w/w) among sampling sites. MeHg concentrations were used to validate food web transfer rate calculations. Intake rates were calculated to assess the potential health impact of the fish consumption. There is no major threat to human health from the presence of Hg in L. nebulosus, based upon reasonable consumption patterns, limited to no more than three meals of L. nebulosus per week. Qatar National Research Fund (QNRF) under the National Priorities Research Program (NPRP) award number NPRP 09-505-1-081

Polychaete annelids (segmented worms) dominated the macrobenthos in sediments located 6–9 km from the Deep Water Horizon (DWH) Oil Spill site five months after the event, based on nine 0.2 m2 box core samples. Numbers of species, abundance, and biodiversity indices in the polychaete taxa were significantly lower than pre-spill values from similar depths in the eastern Gulf of Mexico (GoM). Both non-selective and selective deposit feeders were the most frequent feeding guilds, as expected, but their abundances were significantly lower. An increase in the number of carnivorous Sigalionidae may be a response to an accumulation of petroleum hydrocarbons on the sediment. The concentration of oil in the sediments was low and the source of the oil remains equivocal. Multivariate analyses illustrated the differences between communities near the DWH and those from prior studies in similar deep GoM habitats. In summary, Deep Water Horizon Oil Spill appears to have had a measurable impact on the polychaetes.

This report presents data obtained from cored sediments collected during numerous cruises in the Northwest Atlantic area. The cores were obtained by SCUBA, gravity cores and DSRV ALVIN. The sediments were sampled with 6 centimeter diameter plastic core liners and ranged in length from 9 to 63 centimeters. Analyses conducted on sediment material include organic carbon, organic nitrogen, percent sand-silt-clay, percent calcium carbonate and pore water concentrations of ammonia, nitrite, nitrate, silicate and phosphate. (Author)

Background Patients with Alzheimer's disease (AD) demonstrate the narrowing of retinal veins and decreased retinal venous blood flow compared with control subjects. We assessed whether these abnormalities are present in patients with mild cognitive impairment (MCI). Methods After the determination of the global clinical dementia rating, 52 subjects (10 AD, 21 MCI, and 21 normal controls) underwent retinal hemodynamic profiling. Blood column diameter, blood speed, and blood flow were measured in a major temporal retinal vein using retinal laser Doppler flowmetry. In addition, peripapillary retinal nerve fiber layer (RNFL) thickness was measured using optical coherence tomography. Results Blood column diameter in AD was narrower than in both MCI (P = .004) and controls (P = .002). However, blood speed in both AD (P = .024) and MCI (P = .005) was lower than in controls. As a result, the differences in blood flow between AD and MCI (P = .036), AD and controls (P

PURPOSE: We seek to identify pathogenic mechanisms for diabetic retinopathy that can become therapeutic targets beyond hyperglycemia and hypertension. We investigated if a defective myogenic response of retinal arteries to increased perfusion pressure, which exposes capillaries to increased pressure and flow, is associated with the onset of clinical retinopathy. METHODS: We examined prospectively the incidence of retinopathy in type 1 diabetic individuals tested 4 years earlier for the retinal arterial myogenic response, and in a cross-sectional study the prevalence of defective myogenic response in type 1 patients who had diabetic retinopathy. Among these, we contrasted early-onset (after 15 ± 2 years of diabetes, E-DR; n = 5) to late-onset (after 26 ± 3 years of diabetes, L-DR; n = 7) retinopathy. We measured the myogenic response using a laser Doppler blood flowmeter after a change in posture from sitting to reclining, which increases retinal perfusion pressure. RESULTS: Five of seven participants who 4 years prior had a defective myogenic response had now developed clinical retinopathy; as compared with only one of six participants who 4 years prior had a normal response (P = 0.10). In the cross-sectional study, all participants had normal retinal hemodynamics at steady state. In response to the postural change, only the E-DR group showed defective myogenic response (P = 0.005 versus controls, P = 0.02 versus L-DR) and abnormally high retinal blood flow (P = 0.016 versus controls). CONCLUSIONS: In type 1 diabetic patients, a defective myogenic response of retinal arteries to pressure is not required for the development of clinical retinopathy, but is prominently associated with an accelerated onset of retinopathy.

The biosynthesis of the azabicyclic ring system of the azinomycin family of antitumor agents represents the “crown jewel” of the pathway and is a complex process involving at least 14 enzymatic steps. This study reports on the first biosynthetic step, the inroads, in the construction of the novel aziridino [1,2-a]pyrrolidine, azabicyclic core, allowing us to support a new mechanism for azabicycle formation.

The role of microbial heterotrophs in deep-ocean sediment communities is explored using a simplified model of the cycling of carbon within a generic, size-based food web. Measurements of potential rates of respiration and growth of bacteria appear to be low, given the high concentrations of both microbial biomass and dissolved organic matter (DOM) in pore waters. This enigma can be explained theoretically by assuming that much of the microbial biomass is restricted in function at high pressure and low temperature, that a large fraction of the dissolved organic carbon (DOC) is refractory, and that the small fraction of the DOM that is labile and thus available must be liberated from the particulate pool by extracellular enzyme activity, viral infection or through the feeding processes of the metazoans. Free-living heterotrophic microbes in the sediments thus play a minor role in metazoan food webs, providing only a small fraction of the nourishment of metazoans. On the other hand, microbial hetero...

Experiments reveal that the metabolic precursor aminoacetone is a key intermediate in the production of the antitumor agent azinomycin A relative to the structurally and functionally related agent, azinomycin B. Azinomycin A and B arise through bifurcation of the biosynthetic pathway and competition between metabolic substrates. The availability of the biosynthetic precursors in vivo, aminoacetone for azinomycin A and threonine for azinomycin B, controls the overall ratio of azinomycin A to B produced.

Sedimentation rates were determined for the northern Gulf of Mexico margin sediments at water depths ranging from 770 to 3560 m, using radiocarbon determinations of organic matter. Resulting sedimentation rates ranged from 3 to 15 cm/kyr, decreasing with increasing water depth. These rates agree with long-term sedimentation rates estimated previously using stratigraphic methods, and with estimates of sediment delivery rates by the Mississippi River to the northern Gulf of Mexico, but are generally higher by 1–2 orders of magnitude than those estimated by 210Pbxs methods. Near-surface slope sediments from 2737 m water depth in the Mississippi River fan were much older than the rest. They had minimum 14C ages of 16–27 kyr and δ13C values ranging from −24‰ to −26.5‰, indicating a terrestrial origin of organic matter. The sediments from this site were thus likely deposited by episodic mass wasting of slope sediment through the canyon, delineating the previously suggested main pathway of sediment and clay movement to abyssal Gulf sediments.

Azinomycin B is an environmental DNA crosslinking agent produced by the soil microorganism Streptomyces sahachiroi. While the agent displays potent cytotoxic activities against leukemic cell lines and animal mouse models, the lack of a consistent supply of the natural product has hampered detailed biological investigations on the compound, including its mode of action and biosynthesis. We report here a significant methodological improvement in the culturing of the bacterium, which allows reliable and steady production of the natural product in good yields. The key experimental step involves the culturing of the strain on dehydrated plates, followed by the generation of a two-stage starter culture and subsequent fermentation of the strain under nutrient-starved conditions. We illustrate use of this culture system by investigating the formation of the enol fragment of the molecule in isotopic labeling experiments with threonine and several advanced precursors (beta-ketoamino acid 3, beta-hydroxyamino aldehyde 4, and beta-ketoaminoaldehyde 5). The results unequivocally show that threonine is the most advanced precursor accepted by the NRPS (non-ribosomal peptidyl synthetase) machinery for final processing and construction of the enol moiety of the natural product.

Purpose To characterize the retinal vascular autoregulatory response to ocular perfusion pressure (OPP) changes in patients with glaucoma and in healthy control subjects. Design Observational cohort study. Participants Eighteen patients with open-angle glaucoma (OAG) and 8 control subjects, all females ages 40 to 60 years, were studied. Only subjects with known maximum intraocular pressure less than 22 mmHg in both eyes were included. Methods Arterial diameter and blood speed in the inferior temporal retinal artery of the left eye were measured simultaneously at baseline while sitting, while reclining for approximately 30 minutes, and once again sitting using a retinal laser Doppler instrument. Blood flow rate was computed automatically. Brachial artery blood pressure and heart rate also were measured. Main Outcome Measure Change in blood flow rate while reclining for approximately 30 minutes compared with baseline blood flow rate measured while seated. Results In control subjects, arterial diameter decreased by 7.5±3.4% ( P = 0.0003) and blood speed increased by 24.6±10.8% ( P = 0.004) while reclining compared with baseline. The concomitant change in the blood flow rate (6.5±12.0%; P = 0.15) compared with baseline was not statistically significant. In contrast, OAG patients showed a much broader range of blood flow changes in response to posture change (14.9±37.7%; P = 0.086) compared with baseline. Although there were no significant differences in the flow changes compared with baseline in either group, there was a significant difference in the variance of the blood flow changes in the OAG patients compared with the controls ( P = 0.0025). Division of the OAG patients into subgroups revealed a significant ( P = 0.031) association between baseline OPP and the retinal blood flow response to posture change. Conclusions The authors describe the hemodynamic details of retinal vascular autoregulation in response to posture-induced changes in OPP in healthy subjects and document the lack of such autoregulation in a selected group of patients with OAG.

Aims/hypothesis Abnormalities in retinal haemodynamics have been reported in patients with type 1 diabetes in advance of clinical retinopathy. These abnormalities could therefore be useful as early markers or surrogate endpoints for studying the microangiopathy. Since the DCCT, the increased focus on good glycaemic control is changing the natural history of diabetic retinopathy. Based on this, the aim of this study was to investigate whether patients with type 1 diabetes treated entirely or mostly in the post-DCCT era and tested in the absence of confounding factors show retinal haemodynamic abnormalities. Methods We measured retinal haemodynamics by laser Doppler flowmetry in 33 type 1 diabetic individuals with no or minimal retinopathy (age 30 ± 7 years, duration of diabetes 8.8 ± 4.6 years, 9% showing microaneurysms), and 31 age- and sex-matched non-diabetic controls. The study participants were not taking vasoactive medications, and blood glucose at the time of haemodynamic measurements was required to be between 3.8 and 11.1 mmol/l. Results HbA1c was 7.5 ± 1.2% and blood glucose 7.7 ± 2.8 mmol/l in these type 1 diabetic individuals, indicating relatively good glycaemic control. Retinal blood speed, arterial diameter and blood flow were not different between the diabetic individuals and the matched controls. Conclusions/interpretation Type 1 diabetic patients with no or minimal retinopathy who maintain relatively good glycaemic control do not show abnormalities of the retinal circulation at steady state, even after several years of diabetes. In such patients it may be necessary to test the vascular response to challenges to uncover any subtle abnormalities of the retinal vessels.

SummaryStudies on the mechanism of action of the antitumor agent azinomycin B in vitro suggest that the drug elicits its lethal effects by the formation of interstrand crosslinks within the major groove of DNA. Here, we demonstrate the biological effects of the drug in vivo. Fluorescence imaging revealed localization of azinomycin B in the nuclear region of yeast. Moreover, experiments with oligonucleotide microarrays examined the effects of the drug across the yeast transcriptome. The results demonstrated a robust DNA damage response that supports the proposed role of the drug as a covalent DNA modifying agent. RT-PCR analysis validated the gene changes, and flow cytometry of azinomycin-treated yeast cells demonstrated a phenotypic S phase shift consistent with transcriptional effects.

[reaction: see text] Azinomycins have potential therapeutic value as antitumor agents; however, their biosynthesis is poorly understood. Here, we provide the first demonstration of a protein cell-free system capable of supporting complete in vitro biosynthesis of the antitumor agent azinomycin B. The cell-free system is utilized to probe the cofactor dependence and substrate requirements of the pathway en route to azinomycin.

Results of using a field spectrophotometer and its appropriate protocols as a surrogate method for an oilfield produced water treatment process is presented. Methylene chloride extractions of the produced water before and after treatment maintained a yellow color pigment that was directly proportional to the hydrocarbon concentration. From this, an absorption spectrum and standard curve were developed. A resultant linear plot of the standard curve indicated that there is an excellent correlation (r2=0.9847) between the varying concentrations and the associated absorbance values at a wavelength of 400 nm. Total n-alkane concentration comparisons between the laboratory GC/MS analysis and the spectrophotometry analysis generated data of similar accuracy and precision at concentrations ranging from 1 to 137 mg/l (alpha=0.05). Linear comparisons between GC/MS and spectrophotometric coefficients were near unity, with the constant being near zero, with a correlation coefficient (r2) of 0.99. Based on this study, spectrophotometry is a complimentary method to GC/MS for determining total n-alkane concentrations in oilfield produced water samples.

* BACKGROUND AND OBJECTIVE: Age-related macular degeneration (AMD) leads to morphological changes that can interfere with optical coherence tomography retinal thickness measurements. The effects of AMD on two available retinal thickness scan modes were tested. * PATIENTS AND METHODS: Ninety-four scans, equally divided into Radial Line Scans (RLS) and Fast Macula Scans (FMS), of 42 patients with AMD were reviewed. Patients were graded into 4 categories regarding AMD severity. Each scan mode was evaluated for each AMD category. * RESULTS: In dry moderate AMD, 2% of the RLS and 5% of the FMS thickness measurements failed. In dry progressed AMD, the RLS mode performed better (26% failure rate) than the FMS mode (42% failure rate). However, in exudative AMD the FMS mode performed better (6% failure rate) than the RLS mode (28% failure rate). The difference between the RLS and FMS performance in dry progressed AMD compared with exudative AMD was significant (P < .0001). * CONCLUSION: The optical coherence tomography retinal thickness scan modes perform differently, depending on AMD severity. Retinal thickness algorithms with better performance are needed to facilitate measurements in patients with AMD. [Ophthalmic Surg Lasers Imaging 2005;36:310314.1

Objective To investigate whether there is an association between the magnitude of retinal haemodynamic abnormalities in patients with age-related macular degeneration (AMD) and the degree of severity of the AMD. Methods A retinal laser Doppler system (Canon CLBF 100) was used to measure retinal arterial haemodynamic parameters in 25 eyes of 25 patients with AMD and nine eyes of nine age-matched control subjects. Severity of AMD was classified into Mild (n ¼ 11), Moderate (n ¼ 7), or Severe (n ¼ 7). The pulsatility ratio (PR), the pulsatility index (PI), and the resistivity index (RI) were determined. Results PR, PI, and RI in the patients with AMD were each significantly higher than in the control group, and increased monotonically with increasing severity of AMD. However, there were no differences in mean blood velocity, arterial diameter, or blood flow rate among the groups. This suggests that the increased blood flow pulsatility in the retinal arteries of the eyes with AMD is not due to increased distal vascular resistance, but instead is likely due to a loss of compliance in the arterial vasculature leading to the eye. Conclusion Our results suggest that an increasing vascular rigidity in the systemic arterial circulation is directly associated with

We have compared 14 different sediment incubation chambers, most of them were used on bottom landers. Measurements of mixing time, pressure gradients at the bottom and Diffusive Boundary Layer thickness (DBL) were used to describe the hydrodynamic properties of the chambers and sediment–water solute fluxes of silicate (34 replicates) and oxygen (23 replicates) during three subsequently repeated incubation experiments on a homogenized, macrofauna-free sediment. The silicate fluxes ranged from 0.24 to 1.01 mmol m−2 day−1 and the oxygen fluxes from 9.3 to 22.6 mmol m−2 day−1. There was no statistically significant correlation between measured fluxes and the chamber design or between measured fluxes and hydrodynamic settings suggesting that type of chamber was not important in these flux measurements. For verification of sediment homogeneity, 61 samples of meiofauna were taken and identified to major taxa. In addition, 13 sediment cores were collected, sectioned into 5–10-mm slices and separated into pore water and solid phase. The pore water profiles of dissolved silicate were used to calculate diffusive fluxes of silicate. These fluxes ranged from 0.63 to 0.87 mmol m−2 day−1. All of the collected sediment parameters indicated that the sediment homogenization process had been satisfactorily accomplished. Hydrodynamic variations inside and between chambers are a reflection of the chamber design and the stirring device. In general, pump stirrers with diffusers give a more even distribution of bottom currents and DBL thicknesses than paddle wheel-type stirrers. Most chambers display no or low static differential pressures when the water is mixed at rates of normal use. Consequently, there is a low risk of creating stirrer induced pressure effects on the measured fluxes. Centrally placed stirrers are preferable to off-center placed stirrers which are more difficult to map and do not seem to give any hydrodynamic advantages. A vertically rotating stirrer gives about five times lower static differential pressures at the same stirring speed as the same stirrer mounted horizontally. If the aim is to simulate or mimic resuspension at high flow velocities, it cannot be satisfactorily done in a chamber using a horizontal (standing) rotating impeller (as is the case for most chambers in use) due to the creation of unnatural conditions, i.e. large static differential pressures and pre-mature resuspension at certain locations in the chamber.

Produced water is the single largest volume of wastewater generated by the oil and gas industry. Toxic petroleum hydrocarbons found in oilfield-produced waters have increasingly become the major environmental problem facing the U.S. and world oil and gas industry. Uncontrolled releases to the environment using outdated and inefficient technological control systems and methods have continually put surface and ground water environments at risk. In turn, this has placed the oil and gas industries with increasing environmental regulatory compliance costs. With the decline in oil and natural gas prices and the introduction of more stringent produced water surface discharge permit actions, many of these wells are nearing their economic limit. These low-volume marginal wells are being plugged and abandoned because the production, maintenance, treatment, and disposal costs are higher than the selling price. Therefore, in an effort to keep many of our nation's mature oil and gas fields productive, alternative technologies must be evaluated. This research project provided a comprehensive treatment of produced waters using an activated sludge system. The kinetic coefficients determined resulted in a total petroleum hydrocarbon removal efficiency of 99% at a produced water flow rate of 1890 L/day, and a mean cell residence time of 20 days. Kinetic coefficients were determined to be 0.69 (mg/MLSS)/mg total n-alkanes (TNA) and 0.01, 0.44, 2.00, and 0.27 day−1 for Y, kd, k, Ks, and μmax, respectively. © American Institute of Chemical Engineers Environ Prog, 2004

Objective To report a case of a 33-year-old white woman in whom retinal venous thromboses developed secondary to heparin-induced antiheparin-platelet antibodies. Design Interventional case report. Methods The patient underwent complete ophthalmic and medical examinations. Laser Doppler measurement of retinal blood circulation also was performed. Intervention Prolonged anticoagulation with thrombin inhibitors and warfarin. Main outcome measures Visual symptoms, retinal appearance on clinical examination, and measurement of retinal blood flow by laser Doppler technique. Results The patient experienced a scotoma in the visual field of the left eye, left retinal venous thrombosis, decreased venous blood flow in the left eye, and heparin-induced antiheparin-platelet antibodies in serum. After intervention, the visual symptoms and retinal appearance improved, and retinal blood flow normalized. Conclusions Heparin-induced antiheparin-platelet antibody can lead to thrombosis of the ocular circulation. This index case, which is the first one ever reported in association with antiheparin-platelet antibodies, further illustrates the potential side effects of heparin and widens the spectrum of complications of heparin-induced thrombocytopenia (HIT) and HIT thrombosis syndrome (HITTS).

Purpose To describe a newly developed stabilized retinal laser Doppler instrument, to report the reproducibility of retinal blood flow measurements, and to present examples of its clinical application. Design Experimental study. Methods The intrasession, intersession, and interobserver reproducibility of retinal blood flow measurements obtained using the Canon Laser Blood Flowmeter model CLBF 100 was assessed. Intrasession: the coefficients of variation (CV) for repeated measurements (5X) of retinal vessel diameter (D), time-average centerline blood velocity (V av ), and blood flow (F) were calculated at 18 sites along temporal retinal arteries and 18 sites along temporal retinal veins using both eyes in six healthy volunteers. Intersession: the correlation coefficients and average differences between two sets of measurements at the same 36 retinal sites made by one examiner on two different days were calculated. Interobserver: the correlation coefficients and average differences between two sets of measurements at nine sites (five arterial and four venous) in five eyes of five of the volunteers made by two examiners on the same day were calculated. Results from two patients, one with branch retinal vein occlusion (BRVO), and one with central retinal vein occlusion (CRVO), are used to illustrate abnormal retinal circulatory characteristics. Results Intrasession: CV (mean ± SD) for D, V av , and F were 5.5% ± 2.2%, 13.1% ± 6.3%, and 13.8% ± 4.7% in arteries and 3.5% ± 2.1%, 11.9% ± 5.9%, and 12.7% ± 5.5% in veins. Intersession/interobserver: strong correlations between measurements made by one examiner on two different days and by two examiners on the same day were found in D, V av , and F. Average differences in F were 16.4% ± 12.8% for intersession and 12.6% ± 7.0% for interobserver comparisons. Results from the patient with BRVO show marked differences in flow characteristics in the affected quadrant compared with an unaffected quadrant in the same eye, and to the fellow eye. Results from the patient with CRVO show a dramatic improvement in flow characteristics after clearing of the occlusion. Conclusions The reproducibility results and the fact that blood flow is measured in actual units of μl/min indicate that the instrument can be used for reliable comparison of blood flow characterictics at different retinal vascular sites in the same eye, at comparable sites in both eyes, and for comparison between patients and healthy control subjects.

“While the frequency of disc hemorrhange in the Low-Pressure Glaucoma Treatment Study was not reported, we suspect the study is enriched with patients who demonstrated retinal vascular dysregulation and that brimonidine use favorably altered the retinal hemodynamic profile in a manner that translated into less visual field loss when compared with the timolol-treated group.” Expert Review of Ophthalmology

Net fluxes of respiratory metabolites (O2, dissolved inorganic carbon (DIC), NH4+, NO3−, and NO2−) across the sediment-water interface were measured using in-situ benthic incubation chambers in the area of intermittent seasonal hypoxia associated with the Mississippi River plume. Sulfate reduction was measured in sediments incubated with trace levels of35S-labeled sulfate. Heterotrophic remineralization, measured as nutrient regeneration, sediment community oxygen consumption (SOC), sulfate reduction, or DIC production, varied positively as a function of temperature. SOC was inversely related to oxygen concentration of the bottom water. The DIC fluxes were more than 2 times higher than SOC alone, under hypoxic conditions, suggesting that oxygen uptake alone cannot be used to estimate total community remineralization under conditions of low oxygen concentration in the water column. A carbon budget is constructed that compares sources, stocks, transformations, and sinks of carbon in the top meter of sediment. A comparison of remineralization processes within the sediments implicates sulfate reduction as most important, followed by aerobic respiration and denitrification. Bacteria accounted for more than 90% of the total community biomass, compared to the metazoan invertebrates, due presumably to hypoxic stress.

During crude oil and natural gas exploration and production, large volumes of petroleum hydrocarbon containing ‘produced water’ are concurrently recovered. Produced water is the largest volume waste stream in the exploration and production processes of oil and gas. During onshore oil recovery, the petroleum hydrocarbon/water mixture is processed through various separation units where the water extract is either discharged into above ground storage facilities, or re-injected into a subsurface formation as a permanent disposal/secondary recovery process. In offshore or coastal oil recovery operations, produced water is either discharged through shore side outfalls or coastal rim releases (within 4 miles from shore). In many cases, current disposal practices such as these have caused severe environmental petroleum hydrocarbon contamination to surface, ground and coastal waterways. Therefore, a research project was conducted to evaluate the performance of a field (continuous-flow) activated sludge treatment system for removing petroleum hydrocarbons from Southwestern US oilfield generated produced water. Petroleum hydrocarbon removal efficiencies were determined using gas chromatography/mass spectrometry (GC/MS) and total petroleum hydrocarbon (TPH) analysis. The activated sludge treatment unit maintained a TPH removal efficiency of 98–99% at a solids retention time (SRT) of 20 days and a mixed liquor suspended solids concentration (MLSS) of 730 mg/l. Incurred energy costs were $0.17 per barrel (or $0.004 per gallon) of produced water treated.

• PURPOSE: To assess whether brimonidine 0.15% alters retinal vascular autoregulation and short-term visual function in normal tension glaucoma patients who demonstrate retinal vascular dysregulation. • DESIGN: Nonrandomized clinical trial. • METHODS: In this prospective study, 46 normal tension glaucoma patients not previously treated with brimonidine underwent retinal vascular autoregulation testing and visual function assessment using frequency doubling technology perimetry and equivalent noise motion sensitivity testing. We measured blood flow in a major temporal retinal artery with subjects seated and then while reclined for 30 minutes. Patients having a change in retinal blood flow with posture change outside the range previously found in healthy subjects were classified as having retinal vascular dysregulation. They were treated with brimonidine 0.15% for 8 weeks and designated for retesting. • RESULTS: Twenty-three patients demonstrated retinal vascular dysregulation at the initial visit. Younger age (P = .050) and diabetes (P = .055) were marginally significant risk factors for retinal vascular dysregulation. After the 8-week course with brimonidine, 14 of the 17 patients who completed the study showed a return of posture-induced retinal blood flow changes to levels consistent with normal retinal vascular autoregulation (P < .0001). We found no significant changes in frequency doubling technology perimetry or in motion detection parameters following treatment with brimondine (P > .09 for all tests performed). • CONCLUSIONS: Brimonidine significantly improved impaired retinal vascular autoregulation in normal tension glaucoma patients, but short-term alteration in visual function could not be demonstrated.

A benthic chamber has been developed that utilizes an artificial `gill' to maintain close to ambient dissolved oxygen concentrations within the chamber. The `gill' consists of approximately 12.8 m of silicone tubing through which chamber water is pumped by a controlled submersible peristaltic pump. Via turning this pump on and off, benthic oxygen demand can be determined at various times after deployment; ambient oxygen levels over the sediment can be manipulated so that the influences of hypoxic and anoxic conditions can be determined. Because the tubing is impermeable to charged ions, long-term deployments, at close to ambient internal oxygen levels, also make possible the measurement of fluxes of dissolved components whose fractional rate of change is much less than that of oxygen.

The hypothetical bioenhancement of the endemic benthic biota on an oligotrophic abyssal plain by organic carbon has been investigated with mathematical simulation experiments. First, the responses of the biomass and respiration to seasonal variations in the rain of organic carbon (POC) have been simulated in a simplified benthic assemblage (sediment organic carbon, sediment-dwelling heterotrophs (bacteria, meiofauna, macrofauna and detritus feeding megafauna) and predatory megafauna), with no added organic matter. These calculations were based on measured standing stocks and respiration in the central North Pacific (5.8 km depth, 31°N Lat.×159°W Long.). The dynamic relationships in this natural "oligotrophic" food chain were then subjected to added inputs of organic carbon presumed to be in sewage sludge. Two examples are presented: a modest but continuous input of organic carbon (100 mg C m −2 d −1 ) and a year-long pulse of the same intensity. The continuous input forced the biomass and community respiration to steadily increase until they reached steady state in 15 years at values similar to those found on a typical continental shelf. The pulse exhibited the same pattern, but biomass and respiration returned to levels found under natural oligotrophic conditions several years after cessation of intensified carbon loading. The responses of the sediment community to added organic matter were validated using information from a deep-ocean sewage disposal site (DWD106) off the coast of New Jersey. The models are also used to illustrate an approach for estimating possible transfers of potentially toxic contaminants, such as total polycyclic aromatic hydrocarbons (tPAHs), in lipid-rich eggs. In the future it will be necessary to validate model results with deep-ocean in situ experiments.

To assess whether dorzolamide 2%-timolol 0.5% (D/T) and/or brimonidine 0.2%-timolol 0.5% (B/T) alters retinal vascular autoregulation (RVA) and seated ocular perfusion pressure (sOPP) in primary open angle glaucoma (POAG) patients who demonstrate retinal vascular dysregulation (RVD) on timolol 0.5% alone.In this prospective, observer-masked, crossover study, 21 POAG patients with untreated intraocular pressure (IOP)21 mmHg were treated for 6 weeks with timolol 0.5%. Subsequently, we measured inferior temporal retinal artery blood flow in the left eye with subjects seated and then while reclined for 30 min using the Canon Laser Blood Flowmeter. Subjects with a change in retinal blood flow in response to posture change outside of the range previously found in healthy subjects were designated as having RVD and randomized to either D/T or B/T for 6 weeks and re-tested. This was followed by treatment with the opposite medication.Seven of the 21 subjects demonstrated RVD in response to posture change following timolol 0.5%. Multiple linear regression analysis indicated that lower sOPP was the main determinant of RVD (P=0.033). After treatment with D/T, all 7 converted from RVD to normal RVA status (P=0.001). Four of 6 subjects showed a similar return to normal RVA following B/T (P=0.066). Mid-morning sOPP was 41.1±5.5 mmHg post-timolol, 46.3±6.5 mmHg post-D/T, and 38.6±6.0 mmHg post-B/T (D/T vs. B/T, P=0.026).D/T significantly improved RVA in POAG patients exhibiting RVD while on timolol 0.5% alone. D/T also increased sOPP compared to B/T. There was no significant difference (P=0.37) between D/T and B/T in improving RVA.

The self-exchange electron-transfer (ET) rate constant k22 for 1,2,3,4,5-pentamethylferrocene was determined by NMR line broadening to be 8.5(±0.8) × 106 M-1 s-1 (25 °C, CD3CN/0.09 M Et4NBF4) and k11 for the bis-N,N-bicyclic hydrazine, 9,9‘-bi-9-azabicyclo[3.3.1]nonane, to be 8.7(0.5) × 103 M-1 s-1 (25 °C, CH2Cl2). These self-exchange rate constants are used to analyze cross reactions of these molecules with hydrazines, ferrocenes, and tetramethyl-p-phenylenediamine (TMPD) using Marcus theory. Cross-reaction rate constants for eight reactions are reported. Included are six cross-reactions between methylferrocenes and four cyclic hydrazines, one hydrazine, hydrazine−reaction, and the reduction of TMPD+ by a cyclic hydrazine. These are the first cross-reaction rate constants reported for hydrazine−hydrazine and hydrazine−TMPD+ ET reactions. The cross-reaction rate constants are used to test the application of Marcus theory to hydrazine ET reactions and to extract estimates of hydrazine self-exchange ET rate...

The laser Doppler technique and monochromatic photography were used to measure the total retinal blood flow, temporal/nasal differences in blood flow and the relationship between blood flow and vessel diameter in 5 healthy subjects, aged 54-58 years. Systemic blood pressure (BP) and intraocular pressure were also measured, and the retinal perfusion pressure was calculated. The measurements were compared to those previously obtained from a younger group of 7 healthy subjects, aged 25-38 years. Total retinal blood flow was 73 +/- 13 microliters/min in the middle-aged subjects and was not significantly different from the value measured in young subjects (80 +/- 12 microliters/min). Retinal perfusion pressure was significantly higher in the older subjects, primarily due to elevated systemic BP. The similarity in total flow between the two groups, even though the retinal perfusion pressures were higher in the older group, is an indication of an increased vascular resistance to flow. The increase may be an aging phenomenon or an indication of a well-functioning autoregulatory capacity in the retinal vasculature of the older subjects.

Biokinetic coefficients were evaluated for a New Mexico oilfield produced water. Total n-alkane removal efficiencies greater than 99% were achieved. Using respirometric techniques for determination of the biokinetic constants, values of 1.37 mg/l and 0.136 h−1 were obtained for Ks and μmax, respectively. Evaluation of specific growth rates at various levels of total dissolved solids (TDS) concentration exhibited a distinct reduction from 0.131 to 0.047 h−1, when TDS concentrations exceeded 90,000 mg/l. Changes in cell yield were also evident, however, yields increased from 0.41 to 0.69 mg biomass/mg total n-alkane. Carbon material balances for all respirometric substrate level testing achieved recoveries greater than 98%.

Measurements of seabed oxygen demand and nutrient regeneration were made on continental shelf sediments in the southeast Bering Sea from 1 to 15 June 1981. The mean seabed oxygen demand was relatively modest (267 μM O2 m−2 h−1), equivalent to a utilization of 60 mg organic carbon m−2 day−1. The seasonal build up of ammonium over the mid-shelf domain was generated at least in part by the bottom biota, as previously suggested ( Whitledge et al., 1986 , Continental Shelf Research, 5, 109–132), but on the outer shelf nitrate replaced ammonium as the dominant inorganic nitrogen compound that was regenerated from the sediments. Comparison of oxygen consumption with the organic matter in sedimenting particulate matter (sampled with sediment traps) could imply that benthic processes were not accounting for the fate of considerable quantities of organic matter. Benthic oxygen demand rates, however, probably lag behind the input of the spring bloom to the bottom, thus extending the remineralization process out over time. Consumption by small microheterotrophs in the water column was also a likely sink, although shelf export and advective transport north were possible as well. Estimated nitrification rates in surface sediments could account for only a small fraction of the abrupt increase in nitrate observed in the water column over the shelf just prior to the spring bloom.

A technique to deposit a thin, adherent, uniformly dispersed coating onto the individual particles in a batch of granular or powdered material is described. We have been able to apply successfully a number of coatings to a variety of particulate materials using a fluidized-bed chemical vapor deposition (CVD) technique. By means of this technique we used tri-isobutylaluminum to apply adherent coatings of aluminum on powdered mica and powdered nickel. The powdered mica was also coated with titanium in a fluidized bed reactor in which titanium precursors were generated in situ by the reaction between HCl and metallic titanium. Post treatment of the titanium coated mica with ammonia produced agglomerates coated with TiN. These systems demonstrate the potential utility of the fluidized bed reactor for depositing a variety of coatings onto metallic and non-metallic dispersed materials. Preparation of such coated powders is likely to be valuable in a variety of industrial applications, such as the manufacture of composite structures.

Titanium, TiN and TiOx coatings were deposited on copper and Cu-Ni alloys by chemical vapor deposition in fluidized bed reactors. These coatings provide the copper with a tenfold increase in corrosion resistance in chloride aqueous environments, as determined by a.c. impedance studies.

A coating technique based on (a) chemical vapor deposition, (b) fluidized bed technology and (c) subhalide chemistry was used to siliconize copper. Copper samples were siliconized in silicon beds kept at temperatures in the range 350–550 °C. Alternating current (a.c.) impedance measurements indicate that the corrosion resistance of the coated samples is significantly better than that of uncoated copper.

Streptomyces sahachiroi whole cell feeding experiments, utilizing putative precursors labeled with stable isotopes, established that the epoxide unit of the DNA cross-linked agents, azinomycin A and B, proceeds via a valine-dependent pathway and that hydroxylation and dehydration precedes formation of the terminal epoxide. Sodium 3-methyl-2-oxobutenoate, formed through a transimination reaction, was shown to be the penultimate precursor incorporated into the azinomycin epoxide.

Purpose To evaluate the relationship between retinal circulatory abnormalities and retinal nerve fiber layer (RNFL) thinning in early-stage open-angle glaucoma (OAG) to help elucidate the mechanisms underlying the development of glaucomatous optic neuropathy. Design Prospective cross-sectional. Methods Twelve patients with early OAG and a known maximum untreated intraocular pressure less than 22 mm Hg (age, 61.4 ± 9.7 years; Humphrey visual field mean deviation −2.7 ± 2.1) and eight age-matched healthy control subjects (age, 58.5 ± 8.3 years) were included in the study. Blood column diameter, centerline blood speed, and retinal blood flow were measured in the major inferior temporal retinal artery using a Canon laser Doppler blood flow instrument (CLBF 100; Canon, Tokyo, Japan). Peripapillary RNFL thickness was measured using a Stratus optical coherence tomography instrument. Results On average, there were significant reductions in retinal blood speed ( P = .009) and flow ( P = .010) in OAG patients compared to controls. The RNFL was significantly thinner in the OAG patients compared to controls ( P = .002). There were significant inverse correlations between retinal blood flow and average RNFL thickness and RNFL thickness in the inferior quadrant within the glaucoma group (Rsq = 0.50, P = .01; Rsq=0.62, P = .003). Conclusion The results showed that a thinner RNFL was associated with a higher retinal blood flow in patients with early-stage OAG. The mechanisms underlying this phenomenon remain to be elucidated.

This study compared SLO microperimetry scotoma size measurements with the sizes of lesions assessed with OCT in the areas of scotoma. SLO microperimetry was performed on eight patients to assess the location and extent of scotoma areas. An SLO microperimetry master image was used to localize the scotoma areas in the real time OCT fundus image and to center OCT cross scans on the areas of scotoma. The sizes of the morphological changes measured by OCT were compared with the scotoma size measurements. In each patient, OCT revealed a morphological change located in the area of scotoma. Scotoma sizes ranged from 465 to 3180 μm horizontally and from 570 to 2550 μm vertically. The corresponding lesion sizes ranged from 461 to 2660 μm horizontally and from 523 to 2282 μm vertically. The average difference between SLO and OCT measurements was 2.4% horizontally and 4.9% vertically. There were significant correlations between horizontal and vertical SLO and OCT measurements (Horizontal: R sq=0.955, P

Sediment from a wetland adjacent to an industrial wastewater treatment plant in Sumgayit contained concentrations of total PAHs, total PCBs, aldrin, biphenyl, chlordane, DDT, mercury, beta-endosulfan, heptachlor, alpha-hexacyclohexane (alpha-HCH), gamma-HCH, and several individual PAH congeners that were elevated relative to published sediment quality guidelines. Chemical analyses of tissues from European pond turtles (Emys orbicularis) had increased levels of many of the same chemicals including aldrin, chlordane, heptachlor, alpha-HCH, total PCBs, total PAHs, and mercury, compared to reference turtles. In addition, turtle tissues contained elevated levels of DDD, hexachlorobenzene (HCB), and pentachlorobenzene that were not elevated in the sediment sample. Some differences were observed in contaminant levels between European pond turtles and Caspian turtles (Mauremys caspica) taken from the ponds in Sumgayit. Salmonella/microsome mutagenicity assays on pond sediments were negative or weakly positive. Micronuclei in European pond turtles were statistically correlated with tissue levels of mercury, heptachlor, DDD, HCB, and trans-nonachlor. Microcosm experiments using Russian sturgeon (Acipenser gueldenstaedtii) showed a positive dose-response relationship between exposure to suspended contaminated pond sediment and acute toxicity. Chemical and biological assays used in this study show the industrial area of Sumgayit is heavily contaminated with a complex mixture of toxic pollutants. Exposure to contaminated sediments produced acute effects in Russian sturgeon, but genotoxic effects appear to be slight.

Accurately estimating rates of remineralization of organic matter in sediments (early diagenesis) is a prominent problem for benthic ecologists as well as organic geochemists. McNichol et al. (1988) employed a novel approach to the problem by separating CO{sub 2} produced by respiration from CaCo{sub 3} dissolution, thus theoretically eliminating the need to measure the reduction of terminal electron acceptors in respiration (O{sub 2} NO{sub 3}, SO{sub 4} etc.). Pioneered by Emerson et al. (1980) and Sayles (1981) for deep-sea sediments, this method employs measurements of Ca{sup 2+} in porewater to differentiate between carbonate dissolution and respiration. McNichol et al. (1988) were able to plot metabolic CO{sub 2} profiles over the surface 20 to 30 cm of sediment over an annual cycle at a single station in Buzzards Bay, MA. They used the carbon dioxide profiles in a vertical exchange and reaction model to estimate total organic carbon remineralization per year. Lower Buzzards Bay where McNichol et al. (1988) worked is well studied because of its proximity to the research institutions in Woods Hole. It is the authors intention in this paper to compare the results of these older benthic metabolism studies in Buzzards Bay with those inferred from the modelmore » of the porewater carbon dioxide profile. The published data from three studies have been converted from mL O{sub 2} M{sup {minus}2}H{sup {minus}1} to millimoles and plotted over a 12-month period, thus illustrating the seasonal change in total benthic oxygen demand. The temperature data available at the sites plotted over the year have a somewhat similar patter, and as expected the oxygen demand correlates reasonably well with the temperature.« less

“Produced water” is the single largest volume of waste generated by the oil and gas industry. These waters are generated during crude oil and natural gas production, at both onshore and offshore operations. The amount of produced water generated is dependent upon the method of recovery and the nature of formation. In some formations, large volumes of water are pumped to the surface with the oil and gas in the early stages of production; in others, water is not produced until the formation has been significantly depleted; and in some, water is never generated.

AIMS--The laser Doppler technique was used to compare the capillary blood speed measured at localised sites of the optic nerve head in stable, untreated ocular hypertensive patients with that measured in healthy normal subjects. The stereophotogrammetric technique was also used to measure the retinal nerve fibre layer thickness at the disc margin in the eyes of the patients. METHODS--Doppler broadening measurements were made at superior and inferior temporal disc sites in 18 eyes of 10 ocular hypertensive patients and in 12 eyes of seven age and sex-matched normal subjects. RESULTS--On average, Doppler broadening and, hence, capillary blood speed were significantly higher (p = 0.018) in the patients than in the normal subjects. The largest values of Doppler broadening in the patients were measured at sites adjacent to the thinnest retinal nerve fibre layer. Linear regression analysis showed a significant inverse relation (p = 0.0004) between Doppler broadening and nerve fibre layer thickness in left eyes, and a nearly significant relation (p = 0.06) in right eyes. At temporal sites of the optic nerve head there is a compensatory relation between a thinning nerve fibre layer and a locally increasing blood supply to the optic nerve head. CONCLUSION--Together with previous observations of fluorescein filling defects in similar patients, these results indicate that there is spatial heterogeneity of blood flow in the optic nerve head in stable, untreated ocular hypertensive patients.

A mass budget was constructed for organic carbon on the upper slope of the Middle Atlantic Bight, a region thought to serve as a depocenter for fine-grained material exported from the adjacent shelf. Various components of the budget are internally consistent, and observed differences can be attributed to natural spatial variability or to the different time scales over which measurements were made. The flux of organic carbon to the sediments in the core of the depocenter zone, at a water depth of ∼1000 m, was measured with sediment traps to be ∼65 mg C m−2 day−1, of which 6–24 mg C m−2 day−1 is buried. Oxygen fluxes into the sediments, measured with incubation chambers attached to a free vehicle lander, correspond to total carbon remineralization rates of 49–70 mg C m−2 day−1. Carbon remineralization rates estimated from gradients of Corg within the mixed layer, and from gradients of dissolved ammonia and phosphate in pore waters, sum to only ∼4–6 mg C m−2 day−1. Most of the Corg remineralization in slope sediments is mediated by bacteria and takes place within a few mm of the sediment-water interface. Most of the Corg deposited on the upper slope sediments is supplied by lateral transport from other regions, but even if all of this material were derived from the adjacent shelf, it represents

We used the laser Doppler technique to quantify retinal circulatory abnormalities in three patients with branch retinal artery occlusion and in two patients with branch retinal vein occlusion, each of whom had shown delayed filling on fluorescein angiography. Blood flow in occluded arteries was 40-50% lower than in non-occluded arteries of the same branching order. In the patients with branch retinal vein occlusion blood flow in arteries supplying the affected regions was 80-90% lower than in arteries supplying the unaffected regions. One vein occlusion patient was measured serially over 18 months. Blood flow increased from 4 to 12 microliters/min in the artery supplying the affected region in this patient. The results demonstrate that retinal circulatory abnormalities can be evaluated quantitatively during the course of retinal vascular occlusive disease, and suggest that the efficacy of therapy can be monitored using our techniques.

Purpose The current approach to the prevention of diabetic retinopathy relies on intensive anti-diabetes treatment and is only partially successful. A marker of retinopathy risk would enable strategies of surveillance, screening of adjunct drugs, and targeted drug interventions. The authors sought to identify early abnormalities of retinal vessels that are not prevented by the current therapeutic approach. Methods Retinal thickness (an informer of vascular permeability) and hemodynamic parameters at baseline and longitudinally were measured in 27 subjects (age, 32 ± 9 years [mean ± SD]) with well-controlled type 1 diabetes of 12.4 ± 6.4 years' duration and no retinopathy, and in 27 control subjects. In a subset of 17 patients and 11 controls, the hemodynamic response to reclining, a postural change that increases retinal perfusion pressure, was measured. Results Baseline foveal thickness and hemodynamic parameters were similar in the diabetic and control subjects. Foveal thickness increased over 12 months in the diabetic subjects, from 217 ± 22 μm to 222 ± 20 μm (P = 0.0036), remaining however within the normal range. Reclining uncovered in 47% of diabetic subjects (P = 0.016 compared with controls) an absent myogenic response (i.e., unchanged or increased arterial diameter instead of the normal decrease). The patterns were repeatable. Only the diabetic group with defective vasoconstriction showed widening arterial diameter over 12 months, a change presaging vascular dilatation in diabetic retinopathy. Conclusions Defective myogenic response to pressure was the first detectable abnormality of retinal vessels in subjects with well-controlled type 1 diabetes. Because of its selective occurrence, interpretability in individual patients, and pathogenic potential, the abnormality deserves evaluation as a risk marker for retinopathy.