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Observations of turbulent mixing are quantified in the near‐field region (first several kilometers) of a controlled river flow entering Doubtful Sound, New Zealand. Measurement techniques include direct turbulence measurements using microstructure profilers in both Eulerian and quasi‐Lagrangian perspectives and turbulent overturn analysis. Over 500 profiles of vertical microstructure were collected within the inner fjord. With high flow speeds of the surface plume over 2 m/s and some of the strongest stratification (N2∼10−1 s−2) recorded in the coastal ocean, turbulent overturning (Thorpe, LT) scales are used to indirectly infer turbulence dissipation rates (ϵ) and compared with direct measurements in a quasi‐idealized laboratory setting. There exists an inverse relationship between directly measured estimates of ϵ and distance from the plume discharge point. Peak values of ϵ>10−2 W/kg are observed within 500 m from the discharge point, among the highest turbulence dissipation rates recorded in oceanic shear flows. Thorpe scales range from below 1 cm in the pycnocline to a few meters in the weakly stratified ambient water below the plume. Stratification within the surface layer constrains the vertical dimension, limiting LT. Therefore, LT is an unreliable estimator of L0, where LO is the Ozmidov scale and is used to infer ϵ. Care must thus be taken when applying this method of overturn analysis in an environment where stratification or physical boundaries limit the vertical extent of overturns. Key Points: Turbulence dissipation rates at the base of the plume in the near‐field region are among the highest observed in the oceanThe stratified interface limits the vertical extent of turbulent overturnsThorpe scales determine the size of overturns but should not be used to quantify mixing in the plume [ABSTRACT FROM AUTHOR]

Channel constrictions within an estuary can influence overall estuary-sea exchange of salt or suspended/dissolved material. The exchange is modulated by turbulent mixing through its effect on density stratification. Here we quantify turbulent mixing in Hikapu Reach, an estuarine channel in the Marlborough Sounds, New Zealand. The focus is on a period of relatively low freshwater input but where density stratification still persists throughout the tidal cycle, although the strength of stratification and its vertical structure vary substantially. The density stratification increases through the ebb tide, and decreases through the flood tide. During the spring tides observed here, ebb tidal flow speeds reached 0.7 m s-1 and the buoyancy frequency squared was in the range 10-5 to 10-3 s-2. Turbulence parameters were estimated using both shear microstructure and velocimeterderived inertial dissipation which compared favourably. The rate of dissipation of turbulent kinetic energy reached 1 ? 10-6 m² s-3 late in the ebb tide, and estimates of the gradient Richardson number (the ratio of stability to shear) fell as low as 0.1 (i.e. unstable) although the results show that bottom-boundary driven turbulence can dominate for periods. The implication, based on scaling, is that the mixing within the channel does not homogenise the water column within a tidal cycle. Scaling, developed to characterise the tidal advection relative to the channel length, shows how riverine-driven buoyancy fluxes can pass through the tidal channel section and the stratification can remain partially intact. [ABSTRACT FROM AUTHOR]

Late winter measurements of turbulent quantities in tidally modulated flow under land-fast sea ice near the Erebus Glacier Tongue, McMurdo Sound, identified processes that influence growth at the interface of an ice surface in contact with supercool seawater. The data suggest that turbulent heat exchange at the ocean-ice boundary is characterized by the product of friction velocity and (negative) water temperature departure from freezing, analogous to similar results for moderate melting rates in seawater above freezing. Platelet ice growth appears to increase the hydraulic roughness (drag) of fast ice compared with undeformed fast ice without platelets. We hypothesize that platelet growth in supercool water under thick ice is rate-limited by turbulent heat transfer and that this is a significant factor to be considered in mass transfer at the under-side of ice shelves and sea ice in the vicinity of ice shelves. [ABSTRACT FROM AUTHOR]

The Erebus Glacier Tongue, a small floating glacier in southern McMurdo Sound, is one of the best-studied ice tongues in Antarctica. Despite this, its calving on the 27 February 2013 (UTC) was around 10 yr earlier than previously predicted. The calving was likely a result of ocean currents and the absence of fast ice. The subsequent trajectory of the newly created iceberg supports previous descriptions of the surface ocean circulation in southern McMurdo Sound. [ABSTRACT FROM AUTHOR]

A glacier tongue floating in the coastal ocean presents a significant obstacle to the local flow and so influences oceanic mixing and transport processes. Here acoustic Doppler current profiler and shear microstructure observations very near to a glacier tongue side-wall capture flow accelerations and associated mixing. Flow speeds reached around 40 cm s-1, twice that of the ambient tidal flow amplitude, and generated vertical velocity shear squared as large as 10-5 s-2. During the time of maximum flow, turbulent energy dissipation rates reached 10-5m²s-3, around three decades greater than local background levels. This is in keeping with estimates of the gradient Richardson Number which dropped to ~1 during maximum flow. Associated vertical diffusivities estimated from the shear microstructure results were substantial, reflecting the influence of the glacier on velocity gradients. [ABSTRACT FROM AUTHOR]

A glacier tongue floating in the coastal ocean presents a significant obstacle to the local flow and influences oceanic mixing and transport processes. Here ocean shear microstructure observations at a glacier tongue side-wall show tidally-induced flow pulses and vortices as well as concomitant mixing. Flow speeds within the pulses reached around three times that of the ambient tidal flow amplitude and generated vertical velocity shear as large as 3×10-3 s-1. During the maximum flow period turbulent energy dissipation rates reached a maximum of 10-5 m2 s-3, around three decades greater than local background levels. This is in keeping with estimates of the gradient Richardson Number which dropped to around unity. Associated vertical diffusivities are higher that expected from parameterization, possibly reflecting the proximity of the cryotopography. [ABSTRACT FROM AUTHOR]

The first turbulence profiler observations beneath land fast sea ice which is directly adjacent to an Antarctic ice shelf are described. The stratification in the 325 m deep water column consisted of a layer of supercooled water in the upper 40 m lying above a quasi-linearly stratified water column with a sharp step in density at mid-depth. Turbulent energy dissipation rates were on average 3x10-8 m² s-3 with peak bin-averaged values reaching 4x10-7 m² s-3. The local dissipation rate per unit area was estimated to be 10 m Wm-2 on average with a peak of 50mWm-2. These values are consistent with a moderate baroclinic response to the tides. The small-scale turbulent energetics lie on the boundary between isotropy and buoyancy-affected. This will likely influence the formation and aggregation of frazil ice crystals within the supercooled layer. The data suggest that the large crystals observed in McMurdo Sound will transition from initial growth at scales smaller than the Kolmogorov lengthscale to sizes substantially (1-2 orders of magnitude) greater than the Kolmogorov scale. An estimate of the experiment-averaged vertical diffusivity of mass Kρ yields a coefficient of around 2x10-4 m²s-1 although this increased by a factor of 2 near the surface. Combining this estimate of Kρ with available observations of average and maximum currents suggests the layer of supercooled water can persist for a distance of ∼250 km from the front of the McMurdo Ice Shelf. [ABSTRACT FROM AUTHOR]

The first detailed observations of the motion and loading of a mussel (shellfish) aquaculture long-line are described in order to identify the dominant modes of flow-structure interaction and provide a baseline for prediction of future structures. A long-line is typically a 120 m long sequence of surface floats beneath which is looped rope bearing the mussel crop. Accelerometer and load cell data from sensors mounted on the structure along with remote radar data are examined in the context of wave and current measurements. The mussels comprise the largest mass and drag element of the structure, and the tidally affected pretensioning of the mooring lines dominates the background load. However, waves and currents increase the maximum load by potentially 100% over this value. The floats at each end of the long-line follow the wave orbital motion reasonably well, more so than the floats in the middle of the backbone. The mussel-laden loops of rope (droppers) clearly respond differently to the floats, implying flexibility in the vertical dimension. This suggests that flow around the droppers, which influences mussel feeding ability and hence production, is complex and highly three-dimensional. [ABSTRACT FROM AUTHOR]

Provides information on a study which evaluated the application of subaqueous disposal technique on the water quality of mining pit lakes. Water quality data on pit lakes; Selection of a mathematical water quality model; Results and discussion of the study; Conclusions.

Characteristics of 2 types of pigment mutants of the bluegreen alga, Anacystis nidulans, are described. "Yellow-green" mutants (YG) which have normal chlorophyll but only half the phycocyanin of the parent are similar to the parent in number of reaction centers/cell, number of chlorophylls/reaction center, maximum turnover rate of the reaction centers, quantum yields at 620 and 686 nm and specific growth rate; they have a reduced action at 620 nm. "Blue" mutants (BL) with somewhat higher phycocyanin but only one-third the chlorophyll of the parent are dissimilar to the parent. BL's have fewer reaction centers/cell, a smaller number of chlorophylls/ reaction center, a higher maximum turnover rate of reaction centers, and a lower specific growth rate. BL's show ca. half the quantum yield of the parent at 620 nm and at 686 nm show a "red rise" rather than a "red drop." The consequences attending low chlorophyll in the BL's are more drastic than those attending the low phycocyanin of the YG's. [ABSTRACT FROM AUTHOR]

The recent and widespread media interest highlighting the concerning number of children with poor oral health has, at last, put paediatric dentistry well and truly under the spotlight. Whether on the front page of the Sunday Times (http://www.thesundaytimes.co.uk/sto/news/uk_news/Health/Sugar/article1433860.ece), on GDPUK forums or live Twitter feeds as ITV's The Dentists was broadcast, the whole nation has suddenly awoken to the realisation that tens of thousands of children are undergoing multiple dental extractions under general anaesthesia in the UK every year. This is of course, not a new phenomenon, so why the sudden interest? [ABSTRACT FROM AUTHOR]

This paper describes a model of the diffusive boundary-layer around an aquatic macrophyte blade. Nutrient uptake at the base of the modelled boundary-layer was examined using previously published laboratorydata. The analysis showed that, over the outer velocity range 0.01--0.16 ms-1, nutrient uptake varied between that predicted by flat-plate boundary-layer theory and that expected with no mean advection. A ratio of theoretical and actual nutrient uptake rates was defined as a means of categorising the transition between the two transport models. The modelling was extended to show how fluctuating boundary conditions may enhance nutrient uptake by the macrophyte; the scenario examined here suggested that at otherwise low outer velocities, periodic stripping of the boundary-layer by passing waves increasednutrient uptake by a factor of 10. [ABSTRACT FROM AUTHOR]

Background: Diet plays a pivotal role in the onset and progression of Crohn's disease (CD). Nutritional interventions revealed effects on intestinal inflammation and gut microbial composition. However, data from well-designed and controlled dietary trials are lacking. Therefore, evidence-based dietary recommendations are still unavailable to patients and physicians. Here, we aim to investigate the effects of an evidence-based anti-inflammatory diet, and an ileocolonic-targeted capsule containing vitamin B 2 , B 3 and C (ColoVit) on patients with CD and their healthy household members., Methods and Analysis: In this multicentre, randomised, placebo-controlled, partially blinded nutritional intervention trial, we aim to recruit 255 CD patients with Harvey-Bradshaw Index <8 and a faecal calprotectin (FCal) cut-off of ≥100 µg/g at baseline. Participants will be randomised into two experimental intervention groups and one placebo group. In the experimental groups, participants will either adhere to the Groningen anti-inflammatory diet (GrAID) or ingest an ileocolonic-delivered oral vitamin B 2 /B 3 /C capsule (ColoVit). The study consists of a 12-week controlled interventional phase, which proceeds to a 9-month observational follow-up phase in which patients allocated to the GrAID group will be requested to continue the intervention on their own accord. Household members of participating patients will be asked to participate in the trial as healthy subjects and are allocated to the same group as their peer. The primary study outcome for patients is the change in FCal level from baseline. The primary outcome for household members is the change in gut microbial composition, which is set as secondary outcome for patients., Ethics and Dissemination: The protocol has been approved by the Institutional Review Board of the Stichting Beoordeling Ethiek Biomedisch Onderzoek in Assen, the Netherlands. Written informed consent will be obtained from all participants. Results will be disseminated through peer-reviewed journals and conference presentations., Trial Registration Number: NCT04913467., Competing Interests: Competing interests: GD received a research grant from Royal DSM and received speaker fees from Pfizer, Abbvie and Janssen Pharmaceuticals. All other authors have no conflicts of interest to declare., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Quantitative structure-activity relationship (QSAR) studies were conducted on an in-house database of cytochrome P450 enzyme 1A2 inhibitors using the comparative molecular field analysis (CoMFA), comparative molecular similarity analysis (CoMSIA) and hologram QSAR (HQSAR) approaches. The database consisted of 36 active molecules featuring varied core structures. The model based on the naphthalene substructure alignment incorporating 19 molecules yielded the best model with a CoMFA cross validation value q(2) of 0.667 and a Pearson correlation coefficient r(2) of 0.976; a CoMSIA q(2) value of 0.616 and r(2) value of 0.985; and a HQSAR q(2) value of 0.652 and r(2) value of 0.917. A second model incorporating 34 molecules aligned using the benzene substructure yielded an acceptable CoMFA model with q(2) value of 0.5 and r(2) value of 0.991. Depending on the core structure of the molecule under consideration, new CYP1A2 inhibitors will be designed based on the results from these models.

The input variables for a numerical model of reactive solute transport in groundwater include both transport parameters, such as hydraulic conductivity and infiltration, and reaction parameters that describe the important chemical and biological processes in the system. These parameters are subject to uncertainty due to measurement error and due to the spatial variability of properties in the subsurface environment. This paper compares the relative effects of uncertainty in the transport and reaction parameters on the results of a solute transport model. This question is addressed by comparing the magnitudes of the local sensitivity coefficients for transport and reaction parameters. General sensitivity equations are presented for transport parameters, reaction parameters, and the initial (background) concentrations in the problem domain. Parameter sensitivity coefficients are then calculated for an example problem in which uranium(VI) hydrolysis species are transported through a two-dimensional domain with a spatially variable pattern of surface complexation sites. In this example, the reaction model includes equilibrium speciation reactions and mass transfer-limited non-electrostatic surface complexation reactions. The set of parameters to which the model is most sensitive includes the initial concentration of one of the surface sites, the formation constant (Kf) of one of the surface complexes and the hydraulic conductivity within the reactive zone. For this example problem, the sensitivity analysis demonstrates that transport and reaction parameters are equally important in terms of how their variability affects the model results.

The X-ray crystal structures of four butyrophenone analogues have been completed and are reported herein. These include spiperone hydrochloride (I), N-methylspiperone hydrochloride (II), pimozide (III), and fluspirilene (IV). These structures were compared to other structurally similar molecules with similar pharmacological activity. In addition, a molecular modeling study was done in order to determine the low energy conformations of these molecules. It was found that calculations of parameters that describe the molecular conformations showed that all four molecules were structurally similar. Crystallographic data: [see text]

A 28-year-old woman developed hirsutism, facial edema and clitoromegaly after self-injection of long-acting synthetic androgens. The symptoms were ameliorated by administration of flutamide with a combination oral contraceptive. Flutamide appears to be useful in preventing sequelae of acute androgen excess in women and may be a rational therapy for chronic treatment of androgen excess in women.

7S nerve growth factor (7S NGF) and nerve growth factor I (NGFI) are NGF-containing protein complexes isolated from mouse submandibular glands by different protocols, and reports suggest that the molecules differ chemically. In this study, we compared the molecular properties and subunit compositions of the two proteins. Purified 7S NGF and NGFI electrophoresed to identical positions on polyacrylamide gels in nondissociating buffers, with electrophoretic mobilities indistinguishable from that of unpurified NGF in salivary gland extracts. Ultraviolet absorption curves were identical, and sedimentation coefficients were similar (7.3 +/- 0.25 S for 7S NGF; 7.2 +/- 0.2 S for NGFI) as determined by sedimentation velocity analysis. By sedimentation equilibrium analysis, molecular weights of 135 000-140 000 were obtained for both complexes at protein concentrations in the centrifuge cell greater than 85 micrograms/mL; when protein concentrations within the centrifuge cell ranged from approximately 30 to 100 micrograms/mL at equilibrium, both complexes dissociated. Molecular weight values determined by gel filtration on Bio-Gel P300 and Sephadex G200 resins were similar for both proteins, and the values determined on Sephadex agreed with those obtained by ultracentrifugation. The subunit compositions of the complexes were also similar as determined by nonequilibrium isoelectric focusing, NGFI being composed of proteins that migrated to positions identical with those of the alpha, beta, and gamma subunits of 7S NGF. Furthermore, the stoichiometry of the subunits was similar in the two complexes as determined by radioimmunoassays to each of the subunits and by densitometric analysis of electrophoretic gels. Both methods showed that the complexes contain approximately 2 mol of the alpha and gamma subunits per mole of beta-NGF.(ABSTRACT TRUNCATED AT 250 WORDS)

When levulinic acid, a competitive inhibitor of delta-aminolevulinic acid dehydratase, was added to growing cultures of blue-green algae (cyanobacteria), delta-aminolevulinic acid was excreted into the medium and cell growth was inhibited.

By assuming that the opening of hydrogen bonds due to thermal fluctuations is a very fast step and that the reaction of formaldehyde with the imino or amino group is a slow step, we have constructed a model for the unwinding process of poly(A-U) induced by formaldehyde. The denaturation equation derived from the model is essentially the same as that of the zipper model for moderately long chain lengths. The model predicts the following phenomena which are in agreement with our experimental findings. The rate of unwinding is approximately first order for unfractionated polynucleotides and zero order for fractionated samples. This means that formaldehyde ruptures helical residues sequentially starting from the ends and working toward the center. Our model further predicts that the denaturation rate is linearly dependent on -log[Na+] and pH at low ionic strength and is almost independent of [Na+] and pH at high ionic strength. Spectrophotometric measurements on poly(A-U) were done to confirm our theoretical findings.

A uracil-requiring auxotroph of Anacystis nidulans was isolated after treatment with N-methyl-N'-nitrosoguanidine. Neither precursors in the de novo pyrimidine pathway nor compounds of "salvage" or degradative pathways could replace the uracil requirement. The reversion frequency for mutation to a nonuracil requirement for growth was 2.0 times 10(-8). The calculated average rate of uracil utilization was 1.1 times 10(-17) mol of uracil per unit cell mass/h. The amount of uracil required for the synthesis of a unit cell mass was 3.8 times 10(-17) mol of uracil.

The lowest stages of polymerization of tobacco mosaic virus protein were studied by means of high-speed sedimentation equilibrium experiments. Several distinct modes of polymerization were found. At pH 7.1 the expected monomer-trimer-higher polymer equilibrium was observed--very little dimer was detected at this pH. At pH 7.5, however, a strong dimerization was observed--neither monomer nor trimer was detected at this pH. An octamer appeared to be the only species present other than the dimer. When 0.01 M beta-mercaptoethanol was added to the solvent pH 7.5, the dimer was dissociated, resulting in a monomer-trimer association. The dimerization may be the basis for the larger "doubled" polymers formed by the protein at alkaline pH, while the octamer may correspond to the 8S peak frequently observed in sedimentation velocity experiments at alkaline pH. On the other hand, the monomer-trimer-higher polymer equilibrium may correspond to the single helix formed by the protein at slightly acid pH and to the combination of 4S and 20S peaks seen in sedimentation velocity experiments at slightly acid pH.

The relaxation behavior of the helix-coil transition has been investigated for all sizes of polypeptides. Unlike previously reported results, regardless of the size of polypeptides, the first-order kinetics plays a principal role in the relaxation process when a helical state is relaxed to a half-coiled state [i.e. s(f) is congruent to 1, where s(f) is the helix stability parameter at the final state]. On the other hand, when a helical state is relaxed to a coiled state [i.e., s(f) is less than 1], the zeroth-order kinetics plays a major role. In addition, the range of the validity of a kinetic version of the zipper model has been investigated. We have found that when a helical state is relaxed to a state where s(f) is less than or equal to 1, the zipper model is valid for polypeptides with chain length N satisfying the relation N is less than 1/(sigmagammaC)1/2 where sigma is the cooperativity parameter and gammaC is the coil nucleation rate parameter.

Oxygen isotope fractionation ((18)O/(16)O) at the natural abundance level has been measured during photosynthesis of a blue-green and a green alga. When sufficient attention is paid to removal of contaminating air O(2) before and during the experiments, then the photosynthetic O(2) evolved, as compared to the water O(2), had an average difference of -0.36% for a blue-green alga and -0.80% for a green alga. These experiments suggest that there is no reason to invoke an inverse isotope effect in photosynthesis as part of the explanation for the (18)O enrichment in atmospheric O(2) relative to O(2) in oceanic waters. In addition, in an indirect way, the experiments also support the argument that the bulk of O(2) evolved during photosynthesis comes from water. A 10% contribution of O(2) arising from CO(2) would have been detectable in the present work.