Separate and combined effects of temperature and hypoxia on breathing pattern in the domestic fowl

Summary Minute ventilation (V _E), tidal volume (V _T), respiratory frequency (f) and clavicular air sac gas composition were measured in conscious domestic fowl breathing air and hypoxic gas mixtures at neutral (18±1°C) and raised (33±1°C) air temperatures. Increases inV _E caused by inhalation of 10%, 8% or 6.5% O₂ in N₂, respectively, were independent of temperature although at each level the absoluteV _E was ca. 21·min⁻¹ greater in the panting birds. Changes in respiratory pattern during hypoxia were markedly dependent on temperature. At 18°C almost all of the increasedV _E resulted from increasedf. At 33°C hypoxia led to a strong suppression off and increase inV _T. It is concluded that hyperthermia and hypoxia are additive and non-interactive in their effects on ventilatory drive, in agreement with previously reported effects of hypercapnia and physical exercise on breathing in panting fowl.     

Semicontinuous ethanol fermentation of sugar cane blackstrap molasses by pressed yeast

Summary A mathematical model is proposed to explain the influence of the volume fraction of inoculum on the fermentation time and ethanol productivity in semicontinuous ethanol fermentation of sugar cane blackstrap molasses by pressed yeast.Nomenclature a, b, c, d constants, see equation (5) - E_o initial ethanol concentration - E_f final ethanol concentration - K₁, K₂, K₃ constants, see equation (1) - P ethanol productivity - P_c calculated values of P - P_e experimental values of P - r correlation coefficient - S_o initial TRS concentration - S_m TRS concentration of the feeding mash - T fermentation time (average of the experimental values) - T_c calculated value of T - T_e experimental value of T - TRS total reducing sugars calculated as glucose - U_o initial urea concentration - U_m urea concentration of the feeding mash - V reactor working volume - V_i volume of the inoculum - volume fraction of inoculum=V_i/V     

Optimal temperature and concentration profiles in a cascade of CSTR's performing Michaelis-Menten reactions with first order enzyme deactivation

A necessary condition is found for the intermediate temperatures and substrate concentrations in a series of CSTR's performing an enzyme-catalyzed reaction which leads to the minimum overall volume of the cascade for given initial and final temperatures and substrate concentrations. The reaction is assumed to occur in a single phase under steady state conditions. The common case of Michaelis-Menten kinetics coupled with first order deactivation of the enzyme is considered. This analysis shows that intermediate stream temperatures play as important a role as intermediate substrate concentrations when optimizing in the presence of nonisothermal conditions. The general procedure is applied to a practical example involving a series of two reactors with reasonable values for the relevant five operating parameters. These parameters are defined as dimensionless ratios involving activation energies (or enthalpy changes of reaction), preexponential factors, and initial temperature and substrate concentration. For negligible rate of deactivation, the qptimality condition corresponds to having the ratio of any two consecutive concentrations as a single-parameter increasing function of the previous ratio of consecutive concentrations.List of Symbols C _E,0 mol.m^–3 Initial concentration of active enzyme - C _E,i mol.m^–3 Concentration of active enzyme at the outlet of the i-th reactor - C _S,0 mol.m^–3 Initial concentration of substrate - C _S,i mol.m^–3 Concentration of substrate at the outlet of the i-th reactor - Da _i Damköhler number associated with the i-th reactor ((V _i.k_v,0.C_E,0)/(Q.C_S,0)) - Da _min Minimum value of the overall Damköhler number - Da _tot Overall Damköhler number - E _d J.mol^–1 Activation energy of the step of deactivation of the enzyme - E _m J.mol^–1 Standard enthalpy change of the step of binding of substrate to the enzyme - E _v J.mol^–1 Activation energy of the step of enzymatic transformation of substrate - i Integer variable - j Dummy integer variable - k Dummy integer variable - k _d,i s^–1 Kinetic constant associated with the deactivation of enzyme in the i-th reactor (k _d,o·exp{–E _d/(R.T _i}) - k _d,0 s^–1 Preexponential factor of the kinetic constant associated with the deactivation of the enzyme - K _m,i mol.m^–3 Equilibrium constant associated with the binding of substrate to the enzyme in the i-th reactor, (k _m,o·exp{–E _m}(R.T _i}) - K _m,0 mol.m^–3 Preexponential factor of the Michaelis-Menten constant associated with the binding of substrate to the enzyme - k _v,i s^–1 Kinetic constant associated with the transformation of the substrate by the enzyme in the i-th reactor (k _v,o·exp{–E _v/(R.T _i})) - k _v,0 s^–1 Preexponential factor of the kinetic constant associated with the transformation of the substrate by the enzyme - N Number of reactors in the series - Q m³.s^–1 Volumetric flow rate of reacting liquid through the reactor network - R J.K^–1.mol^–1 Ideal gas constant - T _i K Absolute temperature at the outlet of the i-th reactor - T ₀ K Initial absolute temperature - V _i m³ Volume of the i-th reactor - v _max mol.m^–3.s^–1 Maximum rate of reaction under saturation conditions of substrate - x _i Normalized concentration of substrate (C_S,i/C_{S, 0}) - x _i,opt Optimum value of the normalized concentration of substrate - y _i Dimensionless temperature (exp{–T ₀/T _i}) - y _i,opt Optimum value of the dimensionless temperature Greek Symbols Dimensionless preexponential factor associated with the Michaelis-Menten constant (K _m,0/C_s,0) - Dimensionless activation energy of the step of enzymatic transformation of substrate (E _v/R.T₀)) - Dimensionless standard enthalpy change of the step of binding of substrate to the enzyme (E _m/(R.T₀)) - Dimensionless activation energy of the step of deactivation of the enzyme (E _d/(R.T₀)) - Dimensionless deactivation preexponential factor ((k _d,0.C_S,0)/(k_v,0.C_E,0)     

Quantitative detection of DNA damage in the neuronal cells of the cerebellum and cerebrum by the analysis of Feulgen hydrolysis curves

Summary Touch smears of the cerebellum and cerebrum of ageing rats were fixed with methanol, hydrolyzed with 2N HCl at various temperatures and for various periods, and stained with pararosaniline-Schiff reagent. The hydrolysis curves were determined by fluorescence cytophotometry and were computer fitted to the Bateman function to determine the kinetic parameters, the initial yield of apurinic acid or single-stranded DNA (y ₀), and the rate constants for depurination or denaturation (k ₁) and depolymerization (k ₂). The values for k ₁ (1/k ₁ is correlated with the degree of chromatin condensation) and k ₂ (which reflects the degree of DNA instability) steadily increased with age. The values for y ₀, which may indicate the degree of DNA denaturation or damage present before acid hydrolysis, also increased with age in both the cerebellum and cerebrum; however, this value was lower in the cerebellum untill 15 weeks, with the situation being reversed after 35 weeks, the cross-over time being at about 25 weeks. The values of lnk ₁ and lnk ₂ were plotted as the function of the reciprocal of the absolute temperature (T) (Arrhenius plot) for both the cerebellum and cerebrum of 15- and 74-week-old rats, and the activation energies (E) for depurination and depolymerization were calculated from the slopes. In particular, the values of E for k ₂ decreased much more quickly with age and were smaller in cerebellum. In conclusion, the degree of DNA damage and DNA instability steadily increases in both the cerebellum and cerebrum of ageing rats, and this process is much faster in the cerebellum.In honour of Prof. P. van Duijn     

Thermodynamics of the first transition in writhe of a small circular DNA by Monte Carlo simulation

Monte Carlo simulations are employed to investigate the thermodynamics of the first transition in writhe of a circular model filament corresponding to a 468 base-pair DNA. Parameters employed in these simulations are the torsional rigidity, C = 2.0 × 10⁻¹⁹ dyne cm², and persistence length, P = 500 Å. Intersubunit interactions are modeled by a screened Coulomb potential. For a straight line of subunits this accurately approximates the nonlinear Poisson-Boltzmann potential of a cylinder with the linear charge density of DNA. Curves of relative free energy vs writhe at fixed linking difference (Δ1) exhibit two minima, one corresponding to slightly writhed circles and one to slightly underwrithed figure-8's, whenever Δ1 lies in the transition region. The free energies of the two minima are equal when Δ1_c = 1.35, which defines the midpoint of the transition. At this midpoint, the free energy barrier between the two minima is found to be ΔG_bar = (0.20) k_BT at 298 K. Curves of mean potential energy vs writhe at fixed linking difference similarly exhibit two minima for Δ1 values in the transition region, and the two minimum mean potential energies are equal when Δ1 = 1.50. At the midpoint writhe, Δ1_c = 1.35, the difference in mean potential energy between the minimum free energy figure-8 and circle states is (1.3) k_BT, and the difference in their entropies is 1.3 k_B. Thus, the entropy of the minimum free energy figure-8 state significantly exceeds that of the circle at the midpoint of the transition. The first transition in writhe is found to occur over a rather broad range of Δ1 values from 0.85 to 1.85. The twist energy parameter (E_T), which governs the overall free energy of supercoiling, undergoes a sigmoidal decrease, while the translational diffusion coefficient undergoes a sigmoidal increase, over this same range. The static structure factor exhibits an increase, which reflects a decrease in radius of gyration associated with the circle to figure-8 transition. © 1996 John Wiley & Sons, Inc.     

Conductivity and photoconductivity of NaDNA in the solid state

The d. c. conductivity of five samples of NaDNA in dry state was investigated. All specimens show similar behavior, with specific resistivity at 40°C of the order of 10¹³–10¹⁴ ohm-cm and an energy gap of E_c = 2.04–2.25 eV. Based on the Eley's model for conductivity mechanism, the possibility of conservation of an ordered structure in the dry state (temperature range 20–80°C) is discussed. This is ascribed to the interaction of electron systems of individual bases. From the activation energy values it may be estimated that 17–19 π-electrons take part in the interaction. Photoconductivity measurements indicated activation energies E_f of 0.88–0.96 eV in the visible region.     

Monte Carlo simulation of denaturation of adsorbed proteins

Denaturation of model proteinlike molecules at the liquid–solid interface is simulated over a wide temperature range by employing the lattice Monte Carlo technique. Initially, the molecule containing 27 monomers of two types (A and B) is assumed to be adsorbed in the native folded state (a 3 × 3 × 3 cube) so that one of its sides is in contact with the surface. The details of the denaturation kinetics are found to be slightly dependent on the choice of the side, but the main qualitative conclusions hold for all the sides. In particular, the kinetics obey approximately the conventional first-order law at T > T_c (T_c is the collapse temperature for solution). With decreasing temperature, below T_c but above T_f (T_f is the folding temperature for solution), deviations appear from the first-order kinetics. For the most interesting temperatures, that is, below T_f, the denaturation kinetics are shown to be qualitatively different from the conventional ones. In particular, the denaturation process occurs via several intermediate steps due to trapping in metastable states. Mathematically, this means that (i) the transition to the denatured state of a given molecule is nonexponential, and (ii) the denaturation process cannot be described by a single rate constant k_r. One should rather introduce a distribution of values of this rate constant (different values of k_r correspond to the transitions to the altered state via different metastable states). Proteins 30:168–176, 1998. © 1998 Wiley-Liss, Inc.     

Resting metabolic rate and lung function in fasted and fed rough-toothed dolphins,Steno bredanensis

We measured resting metabolic rate (RMR), tidal volume (V_T), breathing frequency (f_R), respiratory flow, and end-expired gases in rough-toothed dolphins (Steno bredanensis) housed in managed care after an overnight fast and 1–2 hr following a meal. The measured average (± standard deviation) V_T (4.0 ± 1.3 L) and f_R (1.9 ± 1.0 breaths/min) were higher and lower, respectively, as compared with estimated values from both terrestrial and aquatic mammals, and the average V_T was 43% of the estimated total lung capacity. The end-expired gas levels suggested that this species keep alveolar O₂ (10.6% or 80 mmHg) and CO₂ (7.6% or 57 mmHg), and likely arterial gas tensions, low and high, respectively, to maximize efficiency of gas exchange. We show that following an overnight fast, the RMR (566 ± 158 ml O₂/min) was 1.8 times the estimated value predicted by Kleiber for terrestrial mammals of the same size. We also show that between 1 and 2 hr after ingestion of a meal, the metabolic rate increases an average of 29% (709 ± 126 ml O₂/min). Both body mass (M_b) and f_R significantly altered the measured RMR and we propose that both these variables should be measured when estimating energy use in cetaceans.     

Density functional study of oxygen vacancy formation and spin density distribution in octahedral ceria nanoparticles

We report plane wave basis density functional theory (DFT) calculations of the oxygen vacancies formation energy in nanocrystalline CeO _2-x in comparison with corresponding results for bulk and (111) CeO₂ surface. Effects of strong electronic correlation of Ce4f states are taken into account through the use of an effective on-site Coulomb repulsive interaction within DFT+U approach. Different combinations of exchange-correlation functionals and corresponding U values reported in the literature are tested and the obtained results compared with experimental data. We found that both absolute values and trends in oxygen vacancy formation energy depend on the value of U and associated with degree of localization of Ce4f states. Effect of oxygen vacancy and geometry optimization method on spatial spin distribution in model ceria nanoparticles is also discussed.     

Thermodynamic analysis of the physical state of water during freezing in plant tissue, based on the temperature dependence of proton spin-spin relaxation

Multi-proton spin-echo images were collected from cold-acclimated winter wheat crowns (Triticum aestivum L.) cv. Cappelle Desprez at 400 MHz between 4 and ?4 °C. Water proton relaxation by the spin-spin (T2) mechanism from individual voxels in image slices was found to be mono-exponential. The temperature dependence of these relaxation rates was found to obey Arrhenius or absolute rate theory expressions relating temperature, activation energies and relaxation rates, Images whose contrast is proportional to the Arrhenius activation energy (E_a), Gibb's free energy of activation (ΔG^?), and the entropy of activation (ΔS^?) for water relaxation on a voxel basis were constructed by post-image processing. These new images exhibit contrast based on activation energies rather than rules of proton relaxation. The temperature dependence of water proton T₂ relaxation rates permits prediction of changes in the physical state of water in this tissue over modest temperature ranges. A simple model is proposed to predict the freezing temperature kof various tissue in wheat crowns. The average E_a and ΔH^? for water proton T₂ relaxation over the above temperature range in winter wheat tissue were ?6.4 ± 14.8 and ?8.6 ± 14.8kj mol^?1, respectively. This barrier is considerably lower than the E_a for proton translation in ice at 0°C, which is reported to be between 46.0 and 56.5 kj mol^?1     

Non-self-sustained glow discharge with electrostatic confinement of electrons sustained by a fast neutral molecule beam

Experimental study of plasma produced at the nitrogen pressure 0.2–1 Pa in the chamber volume V ≈ 0.12 m³ as a result of injection into the chamber of a broad nitrogen molecule beam with 1–4 keV energy and 0.1–1 A equivalent current is carried out, and the study results are presented. Dependences of the plasma density distribution on the beam equivalent current I _b , energy E _b , and gas pressure p indicate a crucial role of fast molecules in gas ionization, and the probe characteristics reveal two groups of plasma electrons with the temperatures T _e ∼ 0.4 eV and T _e ∼ 16 eV. Immersion in plasma of an electrode isolated from the chamber and application to the electrode of a positive voltage U result in non-self-sustained discharge. When U changes from ∼0.5 to ∼1.5 V, the discharge current I rapidly rises to a certain value I*, and after that the rate of rise dI/dU drops by an order of magnitude. At U ∼ 10 V, the current I rises to I ₀ ≈ 1.5I*, and dI/dU once again drops by an order of magnitude. Current I ₀ specifies the number of electrons produced inside the chamber per second, and it grows up with E _b , I _b , and p. At U > 20 V, due to gas ionization by fast electrons emitted by the chamber and accelerated up to the energy ∼eU in the sheath between the plasma and the chamber walls, the current I rises again. When U grows up to ∼50 V, production of fast electrons with energies exceeding the ionization threshold begins inside the sheath, and the ionization intensity rises dramatically. At U > 150 V, contribution of fast electrons to gas ionization already exceeds the contribution of fast molecules, and the plasma density and its distribution homogeneity inside the chamber both grow up substantially. However, even in this case, the discharge is non-self-sustained, and only at U > 300 V it does not expire when the beam source is switched off.     

Single-molecule measurements of dissociation rates and energy landscapes of binary trans snare complexes in parallel versus antiparallel orientation

Interactions between synaptobrevin 2 (Sb2) and syntaxin 1A (Sx1A) can be readily isolated and studied with the use of force spectroscopy single-molecule measurements. We studied interactions between Sx1A and Sb2 in two different orientations (parallel and antiparallel) using four different terminus configurations of these proteins. Force-loading experiments indicated that protein pairs in any configuration/orientation are zippered. We measured the extension and force for disassembly of these interactions, calculated the spontaneous dissociation lifetimes, and determined their free energies, enthalpies, and entropies. Although the free energies were very similar for all four configurations (∼28 k_BT (Eyring model) and ∼20 k_BT (Kramers model)), the enthalpy changes of binary Sx1A-Sb2 interactions varied between 24.7 k_BT and 33.1 k_BT. This variation is consistent with the conformation changes that occur during disassembly of the various protein terminus configurations, as verified by alterations in the extension. The parallel interactions appear to be energetically somewhat advantageous over antiparallel configurations/orientation, especially when the N-termini of Sx1A-Sb2 are left to interact freely.     

Cluster analysis of respiratory time series

We have investigated the respiratory control system with the hypothesis that, although many variables such as minute ventilation (V _I), tidal volume (V _T),breathing period (T _T),inspiratory duration (T _I),and exspiratory duration (T _E),may be observed, the controller functions more simply by manipulating only 2 or 3 of these. Thus, if tidal volume is the only independent variable, T _Ibeing determined by the off-switch threshold, these variables should have very similar time courses. Anesthetized dogs were subjected to CO₂ breathing and carotid sinus perfusion to stimulate both chemoreceptors. The time series of the variables V _I, V _T, T_T, T_Eand T _Ias well as P _{A CO 2}were determined on a breath by breath basis. Derived characteristics of these time series were compared using Cluster Analysis and the latent dimensionality of respiratory control determined by Factor Analysis. The characteristics of the time series clustered into 4 groups: magnitude (of the response), speed, variability and relative change. One respiratory factor accounted for 86% of the variance for the variability characteristics, 2 factors for magnitude (91%) and relative change (85%) and 3 factors for speed (89%). The respiratory variables were analysed for each of the 4 groups of characteristics with the following results: V _Tand T _I clustered together only for the magnitude and relative change characteristics where as T _Tand T _Eclustered closely for all four characteristics. One latent factor was associated with the [T _T-T_E]group and the other usually with P _{A CO 2}.Supported by USPHS 5t01 01919-05, NIH HL 12564 and GM 07033     

Ventilation and oxygen consumption inAmazona viridigenalis

Summary The BMR (6.00 ml O₂·min^–1) and thermal conductance (0.235 ml O₂·min^–1·°C^–1) ofAmazona viridigenalis, a medium sized parrot, are close to allometrically predicted values for nonpasserine birds, but theT _1c of 26.5 °C is 8.5 °C higher than predicted (Fig. 1). Minimal respiratory frequencies measured in four species of birds average 60% of the rate predicted by a previous equation and yield the relationship, breaths·min^–1= 10.3 kg^–0.32. Frequencies are very dependent upon the methods used to obtain the data (Fig. 3). Resting values of respiratory parameters are poorly defined in the existing literature, and there are no single resting values within the TNZ analogous to a BMR. Rather values change within, as well as below and above, the TNZ. Minimal values of different parameters occur at differentT _a's, not necessarily within the TNZ (Figs. 2, 4, 5). For clarity, resting respiratory parameters should be reported as standard values, analogous to standard metabolic rates, withT _a specified. In birds the pattern of ventilation (f andV _T) changes asT _a changes resulting in different extraction efficiencies at a given minute volume (Figs. 6, 7). This facilitates adjustment to both changing oxygen demands and changing thermoregulatory needs.Abbreviations and symbols BMR basal metabolic rate - TNZ thermoneutral zone - T _a ambient temperature - SMR standard metabolic rate - R.H. relative humidity - f respiratory frequency - br breath - T _b body temperature - T _lc lower critical temperature - Tuc upper critical temperature - T _Rlc respiratory lower critical temperature - RQ respiratory quotient - extraction efficiency - V _T tidal volume - minute volume (=V _T xf)     

Structural Effects and Translocation of Doxorubicin in a DPPC/Chol Bilayer: The Role of Cholesterol

We use molecular dynamics simulations to characterize the influence of cholesterol (Chol) on the interaction between the anticancer drug doxorubicin (DOX) and a dipalmitoyl phosphatidylcholine/Chol lipid bilayer. We calculate the potential of mean force, which gives us an estimate of the free energy barrier for DOX translocation across the membrane. We find free energy barriers of 23.1 ± 3.1 k_BT, 36.8 ± 5.1 k_BT, and 54.5 ± 4.7 k_BT for systems composed of 0%, 15%, and 30% Chol, respectively. Our predictions agree with Arrhenius activation energies from experiments using phospholipid membranes, including 20 k_BT for 0% Chol and 37.2 k_BT for 20% Chol. The location of the free energy barrier for translocation across the bilayer is dependent on composition. As Chol concentration increases, this barrier changes from the release of DOX into the water to flip-flop over the membrane center. The drug greatly affects local membrane structure by attracting dipalmitoyl phosphatidylcholine headgroups, curving the membrane, and allowing water penetration. Despite its hydrophobicity, DOX facilitates water transport via its polar groups.     

Nonradiative energy transfer in oligopeptide chains generated by a monte-cralo mehod including long-range interactions

A Monte-Carlo method including long-range interactions is used to oligopeptide chains in random-coil state. The chains are composed of 4, 9, or 14 repeating units and are labeled with the luminopheres tyrosine or tryptophan. Interactions with a solvent (water) are taken into account in the calculations through modifications of the semiempirical potential-energy functions. The chains represent oligopeptides composed of hydrophobic or hydrophilic amino acid residues. Various properties relavent to the interpretaiton of nonradiative enrgy-transfer experiments, such as the average value of the orientation factor for dipole-dipole interaction of the luminophores, 〈k²〉, the distribution function of the distances between the luminophores f(r_l), the efficiences of energy transfer in the static and dyamic averaging regimes, 〈T〉_s amnd 〈T〉_d, as well as the fluorescence decay I(t) of the donor luminophore in various averaging conditions, are computed. It is shown that, for all chains considered, 〈k²〉 is not vary far form 0.67 and that 〈T〉_s and 〈T〉_d have completely different values. Due to the small extent of correlation between the distances r_l and the mutual orientations of the lumninophores, the decay kinetics 〈I(t)_s corresponding to a static averaging regime can be expressed in terms of distribution functions f(r_l). These results are in agrrement with those obtained previously for the unperturbed chain model.     

Assessment of the adiabatic transformability hypothesis in a ball-bouncing task

The adiabatic transformability hypothesis for non-conservative, non-rate-limited biological systems put forward by Kugler and Turvey [Kugler PN, Turvey MT (1987) Information, natural law, and the self-assembly of rhythmic movements, Erlbaum, Hillsdale, NJ] is evaluated in a ball-bouncing task as a function of skill level. We hypothesized that, when a basketball player increases or decreases the frequency of his limb motion in a vertical ball-bouncing task, the transformation should be characterized as adiabatic. Confirmation of this hypothesis would lend support to the body of knowledge that suggests that physical-biological laws guide the behavior of people engaged in motor tasks, including their acquisition of skill. We videotaped and analyzed four participants – two intermediates and two experts – bouncing a ball from various heights, and measured the energy and kinematic relations of the ball and the participants' body segments. The task presents a challenge to certain predictions of the adiabatic hypothesis in evaluating changes in movement velocity (v) or frequency (f), and energy as adiabatic transformations. Among these are the constant relation between kinetic energy (E _k) per cycle and v, constancy of energy dissipated per cycle (E _t) over changes in v and E _k, the ratio of E _k to E _t per cycle (the “Q” values), and the relation of amplitude to v. From our observations, which are examined in regard to the insights of Kugler and Turvey about the relation of Ehrenfest's adiabatic theorem to biological systems, we confirm the basic adiabatic character of the task in analyzing both the ball alone and the relations of various body segments. In the segmental frame of reference, we found evidence of differences in energy-kinematic relations in the Q values between skill levels. Received: 28 May 1998 / Accepted in revised form: 12 November 1999     

The Roles of Structural Order and Intermolecular Interactions in Determining Ionization Energies and Charge‐Transfer State Energies in Organic Semiconductors

The energy landscape in organic semiconducting materials greatly influences charge and exciton behavior, which are both critical to the operation of organic electronic devices. These energy landscapes can change dramatically depending on the phases of material present, including pure phases of one molecule or polymer and mixed phases exhibiting different degrees of order and composition. In this work, ultraviolet photoelectron spectroscopy measurements of ionization energies (IEs) and external quantum efficiency measurements of charge‐transfer (CT) state energies (E_CT) are applied to molecular photovoltaic material systems to characterize energy landscapes. The results show that IEs and E_CT values are highly dependent on structural order and phase composition. In the sexithiophene:C₆₀ system both the IEs of sexithiophene and C₆₀ shift by over 0.4 eV while E_CT shifts by 0.5 eV depending on molecular composition. By contrast, in the rubrene:C₆₀ system the IE of rubrene and C₆₀ vary by ≤ 0.11 eV and E_CT varies by ≤ 0.04 eV as the material composition varies. These results suggest that energy landscapes can exist whereby the binding energies of the CT states are overcome by energy offsets between charges in CT states in mixed regions and free charges in pure phases.     

Growth and energy budget of F2'all-fish' growth hormone gene transgenic common carp

The growth and energy budget for F₂‘all‐fish’ growth hormone gene transgenic common carp Cyprinus carpio of two body sizes were investigated at 29·2° C for 21 days. Specific growth rate, feed intake, feed efficiency, digestibility coefficients of dry matter and protein, gross energy intake (I_E), and the proportion of I_E utilized for heat production (H_E) were significantly higher in the transgenics than in the controls. The proportion of I_E directed to waste products [faecal energy (F_E) and excretory energy loss (Z_E+U_E) where Z_E is through the gills and U_E through the kidney], and the proportion of metabolizable energy (M_E) for recovered energy (R_E) were significantly lower in the transgenics than in the controls. The average energy budget equation of transgenic fish was as follows: 100 I_E= 19·3 F_E+ 6·0 (Z_E+U_E) + 45·2 H_E+ 29·5 R_E or 100 M_E= 60·5 H_E+ 39·5 R_E. The average energy budget equation of the controls was: 100 I_E= 25·2 F_E+ 7·4 (Z_E+U_E) + 35·5 H_E+ 31·9 R_E or 100 M_E= 52·7 H_E+ 47·3 R_E. These findings indicate that the high growth rate of ‘all‐fish’ transgenic common carp relative to their non‐transgenic counterparts was due to their increased feed intake, reduced lose of waste productions and improved feed efficiency. The benefit of the increased energy intake by transgenic fish, however, was diminished by their increased metabolism.