Differential transform semi-numerical analysis of biofluid-particle suspension flow and heat transfer in non-Darcian porous media

The differential transform method (DTM) is semi-numerical method which is used to study the steady, laminar buoyancy-driven convection heat transfer of a particulate biofluid suspension in a channel containing a porous material. A two-phase continuum model is used. A set of variables is implemented to reduce the ordinary differential equations for momentum and energy conservation (for both phases) to a dimensionless system. DTM solutions are obtained for the dimensionless system under appropriate boundary conditions. We examine the influence of momentum inverse Stokes number (Sk_m), Darcy number (Da), Forchheimer number (Fs), particle loading parameter (p_L), particle-phase wall slip parameter (Ω) and buoyancy parameter (B) on the fluid-phase velocity (U) and particle-phase velocity (U_p). Padé approximants are also employed to achieve satisfaction of boundary conditions. Excellent correlation is obtained between the DTM and numerical quadrature solutions. The results indicate that there is a strong decrease in fluid-phase velocities with increasing Darcian (first-order) drag and the second-order Forchheimer drag, and a weaker reduction in particle-phase velocity field. Fluid and particle-phase velocities are also strongly affected with inverse momentum Stokes number. DTM is shown to be a powerful tool providing engineers with an alternative simulation approach to other traditional methods for multi-phase computational biofluid mechanics. The model finds applications in haemotological separation and biotechnological processing.     

Maize Yield Response to Water Supply and Fertilizer Input in a Semi-Arid Environment of Northeast China

Maize grain yield varies highly with water availability as well as with fertilization and relevant agricultural management practices. With a 311-A optimized saturation design, field experiments were conducted between 2006 and 2009 to examine the yield response of spring maize (Zhengdan 958, Zea mays L) to irrigation (I), nitrogen fertilization (total nitrogen, urea-46% nitrogen,) and phosphorus fertilization (P₂O₅, calcium superphosphate-13% P₂O₅) in a semi-arid area environment of Northeast China. According to our estimated yield function, the results showed that N is the dominant factor in determining maize grain yield followed by I, while P plays a relatively minor role. The strength of interaction effects among I, N and P on maize grain yield follows the sequence N+I >P+I>N+P. Individually, the interaction effects of N+I and N+P on maize grain yield are positive, whereas that of P+I is negative. To achieve maximum grain yield (10506.0 kg·ha⁻¹) for spring maize in the study area, the optimum application rates of I, N and P are 930.4 m³·ha⁻¹, 304.9 kg·ha⁻¹ and 133.2 kg·ha⁻¹ respectively that leads to a possible economic profit (EP) of 10548.4 CNY·ha⁻¹ (CNY, Chinese Yuan). Alternately, to obtain the best EP (10827.3 CNY·ha⁻¹), the optimum application rates of I, N and P are 682.4 m³·ha⁻¹, 241.0 kg·ha⁻¹ and 111.7 kg·ha⁻¹ respectively that produces a potential grain yield of 10289.5 kg·ha⁻¹.     

Mechanisms of flagellar propulsion

Summary Flagellar propulsion takes place in the viscosity-dominated realm of low Reynolds number fluid dynamics. Volumes of fluid are carried in a capture zone around the moving regions of the flagellum, and the flagellar motion achieves propulsion because some of that water is shed from the capture zone, either from the flagellar tip in typical flagellar motion or to the side reached at the end of the effective stroke in the case of ciliary motion. Helical flagellar motion is in principle more efficient than planar beating, and the rotation caused by the former introduces complications in propulsion that may be advantageous, e.g., inEuglena, or disadvantageous, e.g., in a fixed cell. The presence of a surface near to the moving organelle restricts the fluid motion, but this effect enhances ciliary propulsion. There is a great variety of beat patterns, functionally adapted hydrodynamically or in other ways for locomotion, feeding, and other more restricted roles.Abbreviations Re Reynolds number - C_N coefficient of resistance to normal motion - C_T coefficient of resistance to tangential motion - l length - v velocity - fluid density - fluid viscosity - L an element of flagellar length moving at velocity V_L - V_W velocity of a wave - V_N velocity of element L in perpendicular (normal) direction - V_T velocity of element L in tangential direction - F_N force in normal direction - F_T force in tangential direction - F_P propulsive force - F_D drag force - E effective stroke - R recovery stroke - angular velocity of flagellum - angular velocity of body     

Turbulent dynamics of helical perturbations in the edge plasma of the T-10 tokamak

Turbulent dynamics of the edge plasma in the T-10 tokamak is simulated numerically by solving nonlinear MHD equations in the framework of the four-field {?, n, p _e , p _i } reduced two-fluid Braginskii hydro-dynamics. It is shown that the transition from ohmic to electron-cyclotron heating is accompanied by a decrease in the amplitudes of turbulent fluctuations in plasma. This is caused by the enhancement of longitudinal dissipation due to the increase in the electron temperature. However, phase relations between potential fluctuations of different modes change in such a way that the Reynolds turbulent force increases, which leads to an increase in the poloidal velocity in the direction of ion diamagnetic drift. Since the poloidal and ion diamagnetic drift velocities enter into the equation of the radial force balance for ions with different signs, the radial electric field decreases. The simulation results agree qualitatively with the results of experiments in the T-10 tokamak. The dependence of the radial electric field on the plasma density, ion pressure, and neutral density is also calculated.     

Intraspecific variability in functional traits matters: case study of Scots pine

Although intraspecific trait variability is an important component of species ecological plasticity and niche breadth, its implications for community and functional ecology have not been thoroughly explored. We characterized the intraspecific functional trait variability of Scots pine (Pinus sylvestris) in Catalonia (NE Spain) in order to (1) compare it to the interspecific trait variability of trees in the same region, (2) explore the relationships among functional traits and the relationships between them and stand and climatic variables, and (3) study the role of functional trait variability as a determinant of radial growth. We considered five traits: wood density (WD), maximum tree height (H _max), leaf nitrogen content (N_mass), specific leaf area (SLA), and leaf biomass-to-sapwood area ratio (B _L:A _S). A unique dataset was obtained from the Ecological and Forest Inventory of Catalonia (IEFC), including data from 406 plots. Intraspecific trait variation was substantial for all traits, with coefficients of variation ranging between 8 % for WD and 24 % for B _L:A _S. In some cases, correlations among functional traits differed from those reported across species (e.g., H _max and WD were positively related, whereas SLA and N_mass were uncorrelated). Overall, our model accounted for 47 % of the spatial variability in Scots pine radial growth. Our study emphasizes the hierarchy of factors that determine intraspecific variations in functional traits in Scots pine and their strong association with spatial variability in radial growth. We claim that intraspecific trait variation is an important determinant of responses of plants to changes in climate and other environmental factors, and should be included in predictive models of vegetation dynamics.     

Order Statistics Theory of Unfolding of Multimeric Proteins

Dynamic force spectroscopy has become indispensable for the exploration of the mechanical properties of proteins. In force-ramp experiments, performed by utilizing a time-dependent pulling force, the peak forces for unfolding transitions in a multimeric protein (D)_N are used to map the free energy landscape for unfolding for a protein domain D. We show that theoretical modeling of unfolding transitions based on combining the observed first (f₁), second (f₂), …, N^th (f_N) unfolding forces for a protein tandem of fixed length N, and pooling the force data for tandems of different length, n₁ < n₂ < … < N, leads to an inaccurate estimation of the distribution of unfolding forces for the protein D, ψ_D(f). This problem can be overcome by using Order statistics theory, which, in conjunction with analytically tractable models, can be used to resolve the molecular characteristics that determine the unfolding micromechanics. We present a simple method of estimation of the parent distribution, ψ_D(f), based on analyzing the force data for a tandem (D)_n of arbitrary length n. Order statistics theory is exemplified through a detailed analysis and modeling of the unfolding forces obtained from pulling simulations of the monomer and oligomers of the all-β-sheet WW domain.     

Studies on mixing in horizontal rotating tubular bioreactor

Mixing studies in the horizontal rotating tubular bioreactor (HRTB) were done to explore the influences of the liquid level (H _M =0.050.08 m) and the distance between the partition walls (D _S =0.020.07 m) on the mixing performance in the bioreactor described by the “spiral flow” model. The optimised adjustable parameters of the model were correlated with the process parameters of the bioreactor expressed as dimensionless numbers: Reynolds rotation number (Re _N ) and Reynolds axial flow number (Re _D ). The polynomial coefficients of the correlations were correlated further with the liquid level in the bioreactor (H _M ) and the distance between the partition walls (D _S ). In that way, three modified prediction systems (SC-2A, SC-6A and SC-9A) were established. The analysis based on different criteria selected the prediction system SC-9A as the most suitable to describe the mixing performance of HRTB.     

Effects of Temperature, Water Activity, and Syrup Film Composition on the Growth of Wallemia sebi: Development and Assessment of a Model Predicting Growth Lags in Syrup Agar and Crystalline Sugar

We investigated the effects of temperature, water activity (a_w), and syrup film composition on the CFU growth of Wallemia sebi in crystalline sugar. At a high a_w (0.82) at both high (20°C) and low (10°C) temperatures, the CFU growth of W. sebi in both white and extrawhite sugar could be described using a modified Gompertz model. At a low a_w (0.76), however, the modified Gompertz model could not be fitted to the CFU data obtained with the two sugars due to long CFU growth lags and low maximum specific CFU growth rates of W. sebi at 20°C and due to the fact that growth did not occur at 10°C. At an a_w of 0.82, regardless of the temperature, the carrying capacity (i.e., the cell concentration at t = ∞) of extrawhite sugar was lower than that of white sugar. Together with the fact that the syrup film of extrawhite sugar contained less amino-nitrogen relative to other macronutrients than the syrup film of white sugar, these results suggest that CFU growth of W. sebi in extrawhite sugar may be nitrogen limited. We developed a secondary growth model which is able to predict colony growth lags of W. sebi on syrup agar as a function of temperature and a_w. The ability of this model to predict CFU growth lags of W. sebi in crystalline sugar was assessed.     

Light-Limited Growth Rate Modulates Nitrate Inhibition of Dinitrogen Fixation in the Marine Unicellular Cyanobacterium Crocosphaera watsonii

Biological N₂ fixation is the dominant supply of new nitrogen (N) to the oceans, but is often inhibited in the presence of fixed N sources such as nitrate (NO₃ ⁻). Anthropogenic fixed N inputs to the ocean are increasing, but their effect on marine N₂ fixation is uncertain. Thus, global estimates of new oceanic N depend on a fundamental understanding of factors that modulate N source preferences by N₂-fixing cyanobacteria. We examined the unicellular diazotroph Crocosphaera watsonii (strain WH0003) to determine how the light-limited growth rate influences the inhibitory effects of fixed N on N₂ fixation. When growth (µ) was limited by low light (µ = 0.23 d⁻¹), short-term experiments indicated that 0.4 µM NH₄ ⁺ reduced N₂-fixation by ∼90% relative to controls without added NH₄ ⁺. In fast-growing, high-light-acclimated cultures (µ = 0.68 d⁻¹), 2.0 µM NH₄ ⁺ was needed to achieve the same effect. In long-term exposures to NO₃ ⁻, inhibition of N₂ fixation also varied with growth rate. In high-light-acclimated, fast-growing cultures, NO₃ ⁻ did not inhibit N₂-fixation rates in comparison with cultures growing on N₂ alone. Instead NO₃ ⁻ supported even faster growth, indicating that the cellular assimilation rate of N₂ alone (i.e. dinitrogen reduction) could not support the light-specific maximum growth rate of Crocosphaera. When growth was severely light-limited, NO₃ ⁻ did not support faster growth rates but instead inhibited N₂-fixation rates by 55% relative to controls. These data rest on the basic tenet that light energy is the driver of photoautotrophic growth while various nutrient substrates serve as supports. Our findings provide a novel conceptual framework to examine interactions between N source preferences and predict degrees of inhibition of N₂ fixation by fixed N sources based on the growth rate as controlled by light.     

Formulation of a Novel Tianeptine Sodium Orodispersible Film

The present investigation was undertaken with the objective of formulating orodispersible film(s) of the antidepressant drug tianeptine sodium to enhance the convenience and compliance by the elderly and pediatric patients. The novel film former, lycoat NG73 (granular hydroxypropyl starch), along with different film-forming agents (hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and polyvinyl alcohol), in addition to three film modifiers; namely, maltodextrin, polyvinyl pyrrolidone K90 and lycoat RS780 (pregelatinized hydroxypropyl starch) were evaluated. Eight formulae were prepared by the solvent-casting method; and were evaluated for their in vitro dissolution characteristics, in vitro disintegration time, and their physico-mechanical properties. The promising orodispersible film based on lycoat NG73 (F1); showing the greatest drug dissolution, satisfactory in vitro disintegration time and physico-mechanical properties that are suitable for orodispersible films, was evaluated for its bioavailability compared with a reference marketed product (Stablon® tablets) in rabbits. Statistical analysis revealed no significant difference between the bioavailability parameters (C_max (ng/ml), t_max (h), AUC_0–t (ng h ml⁻¹), and AUC_0–∞ (ng h ml⁻¹)] of the test film (F1) and the reference product. The mean ratio values (test/reference) of C_max (89.74%), AUC_0–t (110.9%), and AUC_0–∞ (109.21%) indicated that the two formulae exhibited comparable plasma level-time profiles. These findings suggest that the fast orodispersible film containing tianeptine is likely to become one of choices for acute treatment of depression.Key words: bioavailability from orodispersible films and tablets, fast-dissolving films, orodispersible films, solvent-casting method, tianeptine sodium     

How weak twining lianas adapt to competition with host tree trunks: Case of Merremia boisiana

Fierce competition exists between most stem‐twining lianas and the trunks of host trees. However, Merremia boisiana, a vigorous invasive twining liana, never strangles the host tree. Here, we investigated how M. boisiana stems adjust their twining growth to avoid intense competition with host trees, and how hydraulic conductivity is maintained for rapid asexual reproduction. We evaluated the effects of competition on twining M. boisiana stems (E_m) and host tree trunks (E_h), compared differences in secondary growth between twining and creeping M. boisiana stems, calculated the total number of vessels (N_t), vessel density (Vmm⁻²), average vessel diameter (VD_ave), and percentage of vessels wider than 300 μm in diameter (P₃₀₀) in the secondary xylem, and traced how these parameters change with increasing cross‐sectional area of stem (SA). The results showed that twining M. boisiana stems were competitively weaker, and mean E_m (14.3%) was 21 times greater than that of E_h (0.7%). Secondary growth along the normal direction of the contact surface was significantly inhibited in stems twining on host trees. The lateral secondary growth of these stems was active, forming secondary vascular rings and/or arcs with abundant large vessels. Secondary growth in the central vascular cylinder was also significantly limited in extremely flat twining stems. N_t was positively and linearly correlated with SA. Vmm⁻² and VD_ave fluctuated greatly in younger stems and tended to be stable in older stems. N_t and Vmm⁻² did not significantly differ between twining and creeping stems, while VD_ave and P₃₀₀ were both higher in twining stems compared to creeping stems of the same size. In conclusion, well‐developed lateral anomalous secondary growth prevents twining M. boisiana stems from fiercely competing with their host trees, while stable vessel density and wider, newly formed, vessels ensured sufficient hydraulic conductivity for the rapid asexual reproduction of twining M. boisiana stems.     

Non-Homogeneous Fractal Hierarchical Weighted Networks

A model of fractal hierarchical structures that share the property of non-homogeneous weighted networks is introduced. These networks can be completely and analytically characterized in terms of the involved parameters, i.e., the size of the original graph N_k and the non-homogeneous weight scaling factors r ₁, r ₂, · · · r_M. We also study the average weighted shortest path (AWSP), the average degree and the average node strength, taking place on the non-homogeneous hierarchical weighted networks. Moreover the AWSP is scrupulously calculated. We show that the AWSP depends on the number of copies and the sum of all non-homogeneous weight scaling factors in the infinite network order limit.     

P relaxation responses associated with n(2)/o(2) diffusion in soybean nodule cortical cells and excised cortical tissue

N₂-fixing Bradyrhizobium japonicum nodules and cortical tissue derived from these nodules were examined in vivo by ³¹P nuclear magnetic resonance (NMR) spectroscopy. Perfusion of the viable nodules and excised cortical tissue with O₂ followed by N₂ or Ar caused a loss of orthophosphate (Pi) resonance magnetization associated with the major portion of acidic Pi (δ 0.9 ppm, pH 5.5) residing in the cortical cells. Resumption of O₂ perfusion restored approximately 80% of the intensity of this peak. Detailed examination of the nuclear relaxation processes, spin-lattice relaxation time (T₁), and spin-spin relaxation time (T₂), under perfusion with N₂ or Ar as opposed to O₂, indicated that loss of signal was due to T₁ saturation of the acidic Pi signal under the rapid-pulsed NMR recycling conditions. In excised cortical tissue, Pi T₁, values derived from biexponential relaxation processes under perfusing O₂ were 59% 3.72 ± 0.93 s and 41% 0.2 ± 0.08 s, whereas under N₂ these values were 85% 7.07 ± 1.36 s and 15% 0.39 ± 0.07 s. The T₁ relaxation behavior of whole nodule vacuolar Pi showed the same trend, but the overall values were somewhat shorter. T₂ values for cortical tissue were also biexponential but were essentially the same under O₂ (38% 0.066 ± 0.01 s and 63% 0.41 ± 0.08 s) and N₂ (39% 0.07 ± 0.01 s and 61% 0.37 ± 0.01 s) perfusion. Soybean (Glycine max) root tissue as well as Pi solutions exhibited single exponential T₁ decay values that were not altered by changes in the perfusing gas. These data indicate that oxygen induces a change in the physical environment of phosphate in the cortical cell tissue. Although under certain conditions oxygen has been observed to act as a paramagnetic relaxation agent, model T₁ experiments demonstrate that O₂ does not significantly influence Pi relaxation in this manner. Alternatively, we suggest that an increase in solution viscosity brought on by the production of an occlusion glycoprotein (under O₂ perfusion) is responsible for the observed relaxation changes.     

Mating systems and predictors of relative reproductive success in a Cutthroat Trout subspecies of conservation concern

Mating systems and patterns of reproductive success in fishes play an important role in ecology and evolution. While information on the reproductive ecology of many anadromous salmonids (Oncorhynchus spp.) is well detailed, there is less information for nonanadromous species including the Yellowstone Cutthroat Trout (O. clarkii bouvieri), a subspecies of recreational angling importance and conservation concern. Using data from a parentage‐based tagging study, we described the genetic mating system of a migratory population of Yellowstone Cutthroat Trout, tested for evidence of sexual selection, and identified predictors of mating and reproductive success. The standardized variance in mating success (i.e., opportunity for sexual selection) was significantly greater for males relative to females, and while the relationship between mating success and reproductive success (i.e., Bateman gradient) was significantly positive for both sexes, a greater proportion of reproductive success was explained by mating success for males (r ² = 0.80) than females (r ² = 0.59). Overall, the population displayed a polygynandrous mating system, whereby both sexes experienced variation in mating success due to multiple mating, and sexual selection was variable across sexes. Tests for evidence of sexual selection indicated the interaction between mating success and total length best‐predicted relative reproductive success. We failed to detect a signal of inbreeding avoidance among breeding adults, but the group of parents that produced progeny were on average slightly less related than adults that did not produce progeny. Lastly, we estimated the effective number of breeders (N _b) and effective population size (N _e) and identified while N _b was lower than N _e, both are sufficiently high to suggest Yellowstone Cutthroat Trout in Burns Creek represent a genetically stable and diverse population.     

Heat Transfer in MHD Mixed Convection Flow of a Ferrofluid along a Vertical Channel

This study investigated heat transfer in magnetohydrodynamic (MHD) mixed convection flow of ferrofluid along a vertical channel. The channel with non-uniform wall temperatures was taken in a vertical direction with transverse magnetic field. Water with nanoparticles of magnetite (Fe ₃ O ₄) was selected as a conventional base fluid. In addition, non-magnetic (Al ₂ O ₃) aluminium oxide nanoparticles were also used. Comparison between magnetic and magnetite nanoparticles were also conducted. Fluid motion was originated due to buoyancy force together with applied pressure gradient. The problem was modelled in terms of partial differential equations with physical boundary conditions. Analytical solutions were obtained for velocity and temperature. Graphical results were plotted and discussed. It was found that temperature and velocity of ferrofluids depend strongly on viscosity and thermal conductivity together with magnetic field. The results of the present study when compared concurred with published work.     

Interactive effects of elevated CO2 and precipitation change on leaf nitrogen of dominant Stipa L. species

Nitrogen (N) serves as an important mineral element affecting plant productivity and nutritional quality. However, few studies have addressed the interactive effects of elevated CO₂ and precipitation change on leaf N of dominant grassland genera such as Stipa L. This has restricted our understanding of the responses of grassland to climate change. We simulated the interactive effects of elevated CO₂ concentration and varied precipitation on leaf N concentration (N_mass) of four Stipa species (Stipa baicalensis, Stipa bungeana, Stipa grandis, and Stipa breviflora; the most dominant species in arid and semiarid grassland) using open-top chambers (OTCs). The relationship between the N_mass of these four Stipa species and precipitation well fits a logarithmic function. The sensitivity of these four species to precipitation change was ranked as follows: S. bungeana > S. breviflora > S. baicalensis > S. grandis. The N_mass of S. bungeana was the most sensitive to precipitation change, while S. grandis was the least sensitive among these Stipa species. Elevated CO₂ exacerbated the effect of precipitation on N_mass. N_mass decreased under elevated CO₂ due to growth dilution and a direct negative effect on N assimilation. Elevated CO₂ reduced N_mass only in a certain precipitation range for S. baicalensis (163–343 mm), S. bungeana (164–355 mm), S. grandis (148–286 mm), and S. breviflora (130–316 mm); severe drought or excessive rainfall would be expected to result in a reduced impact of elevated CO₂. Elevated CO₂ affected the N_mass of S. grandis only in a narrow precipitation range. The effect of elevated CO₂ reached a maximum when the amount of precipitation was 253, 260, 217, and 222 mm for S. baicalensis, S. bungeana, S. grandis, and S. breviflora, respectively. The N_mass of S. grandis was the least sensitive to elevated CO₂. The N_mass of S. breviflora was more sensitive to elevated CO₂ under a drought condition compared with the other Stipa species.     

Synthesis, characterization and magnetic properties of new homotrinuclear copper(II) complexes

Two new mononuclear bis(oxamato) complexes with the formula [nBu₄N]₂[M(nabo)] M = Ni (4), Cu (5), with nabo = 2,3-naphthalene-bis(oxamato) have been synthesized as precursors for trinuclear oxamato-bridged transition metal complexes. Starting from 5 the homo-trinuclear complex [Cu₃(nabo)(pmdta)₂(BF₄)](BF₄) · MeCN · Et₂O (7), with pmdta = N,N,N′,N″,N″-pentamethyldiethylenetriamine, has been prepared. The central N,N′-2,3-naphthalene bridge of 7 is so far the most extended π-conjugated bridge of trinuclear bis(oxamato) type transition metal complexes. The goal of this work was to verify the N,N′-2,3-naphthalene bridge of 7 on its magnetic properties in comparison to the N,N′-o-phenylene bridge of the related homo-trinuclear complex [Cu₃(opba)(pmdta)₂(NO₃)](NO₃) · 2MeCN (6) (opba = o-phenylene-bis(oxamato)). The crystal structures of 4-7 were solved. The magnetic properties of 6 and 7 were studied by susceptibility measurements versus temperature. For the intramolecular J parameter, values of −89 cm⁻¹ (6) and −113 cm⁻¹ (7) were obtained. The different J values are discussed based on the crystal structures of 6 and 7.     

Salmonella enterica Serovar Typhimurium and Listeria monocytogenes Acid Tolerance Response Induced by Organic Acids at 20°C: Optimization and Modeling

An acid tolerance response (ATR) has been demonstrated in Listeria monocytogenes and Salmonella enterica serovar Typhimurium in response to low pH poised (i.e., adapted) with acetic or lactic acids at 20°C and modeled by using dynamic differential equations. The ATR was not immediate or prolonged, and optimization occurred after exposure of L. monocytogenes for 3 h at pH 5.5 poised with acetic acid and for 2 h at pH 5.5 poised with lactic acid and after exposure of S. enterica serovar Typhimurium for 2 h at pH 5.5 poised with acetic acid and for 3 h at pH 5.5 poised with lactic acid. An objective mechanistic analysis of the acid inactivation data yielded estimates of the duration of the shoulder (t_s), the log-linear decline (k_max), and the magnitude of a critical component (C). The magnitude of k_max gave the best agreement with estimates of conditions for optimum ATR induction made from the raw data.     

Interaction between the C-terminal domains of N and P proteins of measles virus investigated by NMR

In this paper we investigate the interaction between the C-terminal domains of the measles virus phosphoprotein (XD) and nucleoprotein (N_TAIL) by using nuclear magnetic resonance chemical shift perturbation experiments. Using both N_TAIL constructs and peptides, we show that contrary to the conserved Box2 region (N^489-506), the C-terminal region of N_TAIL (N^513-525) does not directly interact with XD, and yet affects binding to XD. We tentatively propose a model where the C-terminus of N_TAIL would stabilize the N_TAIL-XD complex either via a functional coupling with N^489-506 or by reducing the entropic penalty associated to the binding-coupled-to-folding process.

Structured summary

MINT-7009780, MINT-7009793, MINT-7009808: N-tail (uniprotkb:Q89933) and P (uniprotkb:P03422) bind (MI:0407) by nuclear magnetic resonance (MI:0077)     

Lake Number,a Quantitative Indicator of Mixing Used to Estimate Changes in Dissolved Oxygen

Lake Number, L_N, values are shown to be quantitative indicators of deep mixing in lakes and reservoirs that can be used to estimate changes in deep water dissolved oxygen (DO) concentrations. L_N is a dimensionless parameter defined as the ratio of the moments about the center of volume of the water body, of the stabilizing force of gravity associated with density stratification to the destabilizing forces supplied by wind, cooling, inflow, outflow, and other artificial mixing devices. To demonstrate the universality of this parameter, L_N values are used to describe the extent of deep mixing and are compared with changes in DO concentrations in three reservoirs in Australia and four lakes in the U.S.A., which vary in productivity and mixing regimes. A simple model is developed which relates changes in L_N values, i.e., the extent of mixing, to changes in near bottom DO concentrations. After calibrating the model for a specific system, it is possible to use real-time L_N values, calculated using water temperature profiles and surface wind velocities, to estimate changes in DO concentrations (assuming unchanged trophic conditions).