Static Concentration Research Articles

Identifying Static and Kinetic Lipid Phenotypes by High Resolution UPLC–MS: Unraveling Diet-Induced Changes in Lipid Homeostasis by Coupling Metabolomics and Fluxomics

A novel method to differentiate diet-induced alterations in plasma lipid phenotypes "static (concentration of lipids) and kinetic (endogenous production, e.g., denovo lipogenesis)" was employed. C57Bl6 mice were randomized into 2 groups and fed either a high-carbohydrate, low-fat (HC) or a carbohydrate-free, high-fat diet (HF) diet for 13 days; D(2)O was administered via intraperitoneal injection and then adding D(2)O to the drinking water for 96 h. Principal component analysis (PCA) revealed differences in the plasma lipid content, for example, triglycerides (TG) 50:2, 50:3, and 52:2 were up-regulated in mice fed the HC diet, whereas TG 52:4, 52:1, 54:5, 54:3, 54:4, and 54:2 were higher in animals fed the HF diet. However, although the fractional contribution of synthesis was ~10-fold lower in HF vs HC fed mice, changes in TG concentration were not entirely mediated by altered de novo lipogenesis. In addition, the ability to couple isotope labeling measurements with PCA analyses revealed cases where there were no differences in the concentration of a compound but its source was substantially altered. In summary, this strategy determined (i) the presence/absence of differences in concentration and (ii) the contribution of different pathways and synthesis that could affect lipid biology in a mouse model respectively.

Room-Air Versus Oxygen Administration for Resuscitation of Preterm Infants: The ROAR Study

We conducted a blinded, prospective, randomized control trial to determine which oxygen-titration strategy was most effective at achieving and maintaining oxygen saturations of 85% to 92% during delivery-room resuscitation. Infants born at 32 weeks' gestation or less were resuscitated either with a static concentration of 100% oxygen (high-oxygen group) or using an oxygen-titration strategy starting from a concentration of 100% (moderate-oxygen group), or 21% oxygen (low-oxygen group). In the moderate- and low-oxygen groups, the oxygen concentration was adjusted by 20% every 15 seconds to reach a target oxygen saturation range of 85% to 92%. Treatment failure was defined as a heart rate slower than 100 beats per minute for longer than 30 seconds. The moderate-oxygen group spent a greater proportion of time in the target oxygen saturation range (mean: 0.21 [95% confidence interval: 0.16-0.26]) than the high-oxygen group (mean: 0.11 [95% confidence interval: 0.09-0.14]). Infants in the low-oxygen group were 8 times more likely to meet the criteria for treatment failure than those in the high-oxygen group (24% vs 3%; P = .022). The 3 groups did not differ significantly in the time to reach the target oxygen saturation range. Titrating from an initial oxygen concentration of 100% was more effective than giving a static concentration of 100% oxygen in maintaining preterm infants in a target oxygen saturation range. Initiating resuscitation with 21% oxygen resulted in a high treatment-failure rate.

Spectral properties of aluminium doped zinc oxide thin films prepared by SILAR method

The spectral properties of undoped and Al doped ZnO nano thin films prepared using double dip method otherwise called SILAR method (Successive Immersion Layer Adsorption Reaction) are reported. The thin films were having polycrystalline hexagonal structure. The optical properties of these films are studied and reported. The optical constants like the band gap (E g ), refractive indices (n, k), dielectric constant (e), optical conductivity (σ), were estimated using an approximation algorithm developed from established procedures using transmittance spectrum of the thin films. The average excitation energy (E 0), oscillator strength (E d ), effective mass (m*), plasma frequency (ω p ), static dielectric constant (e∞) and carrier concentration (N) are also estimated and reported. The highly transparent thin films showed nanowires protruding from stacked nanorods on SEM inspection that signifies the suitability of these thin films for gas sensors.

SU-F-BRA-05: Dual-Energy Contrast-Enhanced Breast Tomosynthesis: Signal Response to Tissue Contrast Uptake Kinetics

Purpose: Dual‐energy contrast‐enhanced digital breast tomosynthesis (DE CE‐DBT) is a promising technique to identify lesions on the basis of angiogenesis. Several potential imaging acquisition protocols exist for DE CE‐DBT. In this work we experimentally evaluate the sensitivity of the reconstructed image signal to timing of low (L) and high (H) energy images and changes in iodine concentration during image acquisition.Methods: Fifteen angular views of a breast‐equivalent phantom with spherical lesions were acquired over a 43.75 degree angular extent with H and L spectra. Iodine concentrations were varied from 0 to 3.0 mg/ml (0.1 mg/ml increments) between successive dual‐energy acquisitions. These datasets were used to simulate contrast uptake for a range of clinically relevant patterns in post‐processing. For each pattern and a variety of acquisition protocols, the dual‐energy recombined reconstructions are characterized in terms of the signal‐difference‐to‐noise ratio (SDNR) between the lesion and background.Results: The reconstructed signal is expected to represent an average of the signal from each projection image, so we compared dynamic simulations to reconstructions of the equivalent mean static iodine concentration. For a 9.5 mm diameter lesion, and for all acquisition protocols and enhancement patterns, when the L/H image pairs are acquired simultaneously, the SDNR is within 5% of the SDNR in a static image. With up to a 0.1 mg/ml iodine increase between the L and H images (upper limit of uptake rate) the SDNR is within 10% of the static case. When separate L/H energy tube sweeps are used for image acquisition, the measured SDNR can differ from the static case by as much as 30% Conclusions: For quantitative and high quality DE CE‐DBT reconstructions, the data suggest that the L and H image acquisitions be made within one x‐ray tube sweep. Separate L/H tube sweeps can degrade SDNR for particular enhancement patterns. This work was supported in part through a research collaboration with GE Healthcare.

Non-invasive assessment of static scatterer concentration in phantom body fluids using laser speckle contrast analysis technique

An adequate amount of supply of blood to the body organs is essential for the optimum survival and function of the cells. The Red Blood Cells (RBC) which are the most abundant cells of the blood transports hemoglobin which in turn carries oxygen from the lungs to the tissues. And hence its concentration in blood is an important factor. In this paper, we are presenting LAser Speckle Contrast Analysis (LASCA) as a tool for analyzing RBC concentration. Preliminary results obtained using body fluid such as blood mimicking phantoms are presented here. The technique described provides a non-contact, non-scanning and whole field method for assessing RBC concentration non-invasively.

Rapid spatial and temporal controlled signal delivery over large cell culture areas

Controlled chemical delivery in microfluidic cell culture devices often relies on slowly evolving diffusive gradients, as the spatial and temporal control provided by fluid flow results in significant cell-perturbation. In this paper we introduce a microfluidic device architecture that allows for rapid spatial and temporal soluble signal delivery over large cell culture areas without fluid flow over the cells. In these devices the cell culture well is divided from a microfluidic channel located directly underneath the chamber by a nanoporous membrane. This configuration requires chemical signals in the microchannel to only diffuse through the thin membrane into large cell culture area, rather than diffuse in from the sides. The spatial chemical pattern within the microfluidic channel was rapidly transferred to the cell culture area with good fidelity through diffusion. The cellular temporal response to a step-function signal showed that dye reached the cell culture surface within 45 s, and achieved a static concentration in under 6 min. Chemical pulses of less than one minute were possible by temporally alternating the signal within the microfluidic channel, enabling rapid flow-free chemical microenvironment control for large cell culture areas.

A comprehensive approach to soil‐atmosphere trace‐gas flux estimation with static chambers

A new procedure (HMR) for soil‐atmosphere trace‐gas flux estimation with static chambers is presented. It classifies data series into three categories according to criteria based on the application of a particular non‐linear model and provides statistical data analyses for all categories. The two main categories are non‐linear and linear concentration data, for which data are analysed by, respectively, the non‐linear model and linear regression. The third category is represented by concentration data within the range of experimental error, or noise, from sites with no significant flux. Data in this category may be analysed by linear regression or simply classified as no flux. The particular non‐linear model has been selected among alternatives because its exponential curvature generally fits non‐linear static chamber concentration data well, and because it can be proven, mathematically, to be robust against horizontal gas transport through the soil or leaks in the chamber. The application of the HMR procedure is demonstrated on 244 data series of nitrous oxide accumulation over time. On average, 47% of these data were non‐linear, with an average flux increase over linear regression of 52%. The classification and analysis of data with a small signal‐to‐noise ratio requires special attention, and it is demonstrated how diagnostic graphical plots may be used to select the appropriate data analysis. The HMR procedure has been implemented as a free add‐on package for the free software R and is available for download through CRAN (http://www.r‐project.org).

Bactericidal activity of the diarylquinoline TMC207 against Mycobacterium tuberculosis outside and within cells

The bactericidal activities of the diarylquinoline TMC207 in a liquid culture medium started with a bacteriostatic phase lasting about 7 days and then continued with a dose-related bactericidal phase. In comparison, its intra-cellular activity in primary mouse peritoneal macrophages (PM) and in the J774 macrophage-like cell line had little or no static phase so that the bactericidal kill was evident by 5-7 days presumably due to low bacterial ATP levels. Bactericidal activities in the three systems were compared by estimating the rate of bacterial killing (K) during exposure to 0.12-1.0 μg/ml TMC207 which were similar at, -0.35 in the J774 cells and -0.27 in mouse PM (p = 0.6) with each lower than -0.11 in extra-cellular cultures (p < 0.001) and [2] the TMC207 concentration at the intersection between the curve relating cfu count to TMC207 concentration and the cfu count at day-0, defined as the static concentration. Static concentrations were 0.22 μg/ml for extra-cellular cultures, 0.17 μg/ml for mouse PM and 0.06 μg/ml for J774 cells, significantly lower than the extra-cellular value (p < 0.001). Thus, the intra-cellular activity of TMC207 is clearly greater than its extra-cellular activity mainly because the preliminary static phase was a shorter or absent.

Activity of quinupristin/dalfopristin against extracellular and intracellular Staphylococcus aureus with various resistance phenotypes

Treatment of chronic or recurrent Staphylococcus aureus infections may require using antibiotics with activity against intracellular multiresistant organisms. Quinupristin/dalfopristin (3:7) has been examined in this context. Quinupristin and dalfopristin were used separately or mixed. Strains used were: (i) methicillin-susceptible and -resistant S. aureus (MSSA and MRSA); (ii) one vat(B) MSSA and msr(A/B) MRSA; (iii) erm(A)+ [MSSA, MRSA, vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA)]; and (iv) one erm(A/B)+ cfr+ MRSA resistant to quinupristin, dalfopristin and their combination. Assessment of activity was determined by: (i) MICs (CLSI method); and (ii) concentration-response curves in broth and after phagocytosis by THP-1 macrophages, with descriptors of the model (Emin) and the pharmacodynamic response [maximal relative efficacy (Emax), relative potency (EC50) and apparent static concentration (Cstatic)]. erm(A)-positive strains were all susceptible to quinupristin/dalfopristin (except strain CM05), with MICs not adversely influenced by acid pH or by the MRSA, VISA or VRSA character of the strain. In concentration-response experiments, quinupristin/dalfopristin showed similar patterns for all strains (except strain CM05), with a >3 log10 cfu decrease in broth and a 1.3 [erm(A) strain] to 2.6 [fully susceptible, vat(B) and msr(A/B) strains] log10 cfu decrease for intracellular bacteria at the maximal extracellular concentration tested (25 mg/L). Maximal extracellular and intracellular activity was obtained for a quinupristin/dalfopristin ratio of 3:7. For strain CM05, quinupristin/dalfopristin was static in all conditions. Based on historical comparisons with rifampicin, fluoroquinolones, lipoglycopeptides and other antistaphylococcal drugs with a large accumulation in eukaryotic cells, quinupristin/dalfopristin appears to be one of the most active antibiotics against intracellular S. aureus studied in this model so far, largely irrespective of its resistance phenotype.

Intra- and extracellular activity of linezolid against Staphylococcus aureus in vivo and in vitro

Treatment of Staphylococcus aureus infections remains problematic (slow responses and frequent recurrences). Intracellular persistence of the S. aureus could explain those difficulties because of impaired intracellular efficacy of antibiotics. Our aim was to study linezolid for its intracellular activity. (i) Pharmacodynamic (PD) analysis of intracellular activity using in vitro (THP-1 macrophages) and in vivo (mouse peritonitis) models with determination of key dose-response parameters [maximal relative efficacy (E(max)), relative potency (EC(50)) and static concentration (C(static))] towards methicillin-susceptible S. aureus (ATCC 25923; clinical isolate) with linezolid MICs of 4 mg/L; (ii) pharmacokinetic (PK) analysis in uninfected mice for determination of C(max), AUC and half-life for total and free drug; and (iii) determination of the predictive PK/PD parameter (fT > MIC, fAUC(24)/MIC or fC(max)/MIC) for therapeutic outcome. In vitro, linezolid showed an E(max) of approximately 1 log(10) cfu reduction compared with initial inoculum both intra- and extracellularly and an approximately 3-fold increased relative potency (lower EC(50) and C(static)) intracellularly. In vivo, the efficacy of linezolid was impaired (<0.5 log(10) reduction extracellularly; failure to reduce the cfu to less than the initial load intracellularly) with, however, an increased intracellular potency (lower EC(50)). Infection outcome correlated better with the fAUC(24)/MIC (R(2) = 55%) than with the fT > MIC parameter (R(2) = 51%) for the extracellular compartment, but no parameter emerged as significant for the intracellular compartment. Linezolid exerts only a weak intracellular activity against the strains of S. aureus tested, even though, in contrast to most other antibiotics, its potency does not appear impaired in comparison with the extracellular activity.

A simple in vitro PK/PD model system to determine time–kill curves of drugs against Mycobacteria

In vivo tuberculosis is exposed to continually changing drug concentrations for which static minimum inhibitory concentration (MIC) testing may be a poor surrogate. While in vitro approaches to determine time-kill curves for antibiotics have been widely applied in assessing antimicrobial activity against fast growing microorganisms, their availability and application for slow-growing microorganisms including Mycobacterium tuberculosis has so far been scarce. Thus, we developed a novel simple in vitro pharmacokinetic/pharmacodynamic (PK/PD) model for establishing time-kill curves and applied it for evaluating the antimicrobial activity of different dosing regimens of isoniazid (INH) against Mycobacterium bovis BCG as a surrogate for virulent M. tuberculosis. In the in vitro model M. bovis BCG was exposed to INH concentration-time profiles as usually encountered during multiple dose therapy with 25, 100 and 300mg/day in humans who are fast or slow INH metabolizers. Bacterial killing was followed over time by determining viable counts and the resulting time-kill data was analyzed using a semi-mechanistic PK/PD model with an adaptive IC(50) function to describe the emergence of insensitive populations of bacteria over the course of treatment. In agreement with previous studies, the time-kill data suggest that AUC(0-24)/MIC is the PK/PD index that is the most explanatory of the antimicrobial effect of INH. The presented in vitro PK/PD model and associated modeling approach were able to characterize the time-kill kinetics of INH in M. bovis BCG, and may in general serve as a potentially valuable, low cost tool for the assessment of antibacterial activity in slow-growing organisms in drug development and applied pharmacotherapy.

Influence of relaxation of the atomic order in f.c.c.‐Ni–Al alloys on X‐ray diffuse scattering

AbstractThe atomic short‐range order (SRO) for the substitutional f.c.c.‐Ni–9 at.% Al single‐crystal solution is investigated using the X‐ray diffuse‐scattering method (supplemented by Monte Carlo simulation studies) and analyzing the salient features of the second‐order phonon diffuse scattering of X‐rays. As shown, in quenched state, the SRO corresponds to the presence in alloy of the static concentration waves with kX(0 0 1) and k(0 0 0.2) wave vectors. Initial SRO‐kinetics stage is attended by the noticeable increasing of the diffuse‐scattering intensities for wave vectors close to structural (Bragg) reflexes. Parameters of the time dependence of X‐ray diffuse‐scattering intensity for f.c.c.‐Ni–9 at.% Al alloy (after quenching) at low annealing temperature (373 K) are significantly different for different wave vectors generating the ordering and/or clustering processes.

Order–disorder transformation in the binary MPt3 and ternary CuMPt6 (M=3d metals) alloys

Abstract The order–disorder(O–D) transformation in the binary MPt 3 and the ternary CuMPt 6 (M=3d transition metals) alloys were studied. The O–D transformation temperatures ( T c ) were calculated by combining the method of pseudopotentials with the static concentration waves. The method originally proposed by Khachaturyan [Progress in Materials Science, vol. 22, Pergamon Press Ltd., Oxford, 1978, pp. 47–49; Phys. Met. Metallography 13 (1962) 493; Sov. Phys. Solid State 5 (1963) 16; Sov. Phys. Solid State 5 (1963) 548] was applied to the case of ternary CuMPt 6 alloys by using the concept of a pseudoatom. It is found that this model predicts results that are consistent with the experimental data.

Activities of Ceftobiprole and Other Cephalosporins against Extracellular and Intracellular (THP-1 Macrophages and Keratinocytes) Forms of Methicillin-Susceptible and Methicillin-ResistantStaphylococcus aureus

Staphylococcus aureus is an opportunistic intracellular organism. Although they poorly accumulate in eukaryotic cells, beta-lactams show activity against intracellular methicillin (methicillin)-susceptible S. aureus (MSSA) if the exposure times and the drug concentrations are sufficient. Intraphagocytic methicillin-resistant S. aureus (MRSA) strains are susceptible to penicillins and carbapenems because the acidic pH favors the acylation of PBP 2a by these beta-lactams through pH-induced conformational changes. The intracellular activity (THP-1 macrophages and keratinocytes) of ceftobiprole, which shows almost similar in vitro activities against MRSA and MSSA in broth, was examined against a panel of hospital-acquired and community-acquired MRSA strains (MICs, 0.5 to 2.0 mg/liter at pH 7.4 and 0.25 to 1.0 mg/liter at pH 5.5) and was compared with its activity against MSSA isolates. The key pharmacological descriptors {relative maximal efficacy (E(max)), relative potency (the concentration causing a reduction of the inoculum halfway between E(0) and E(max) [EC(50)]), and static concentration (C(s))} were measured. All strains showed sigmoidal dose-responses, with E(max) being about a 1 log(10) CFU decrease from the postphagocytosis inoculum, and EC(50) and C(s) being 0.2 to 0.3x and 0.6 to 0.9x the MIC, respectively. Ceftobiprole effectively competed with Bocillin FL (a fluorescent derivative of penicillin V) for binding to PBP 2a at both pH 5.5 and pH 7.4. In contrast, cephalexin, cefuroxime, cefoxitin, or ceftriaxone (i) were less potent in PBP 2a competitive binding assays, (ii) showed only partial restoration of the activity against MRSA in broth at acidic pH, and (iii) were collectively less effective against MRSA in THP-1 macrophages and were ineffective in keratinocytes. The improved activity of ceftobiprole toward intracellular MRSA compared with the activities of conventional cephalosporins can be explained, at least in part, by its greater ability to bind to PBP 2a not only at neutral but also at acidic pH.

Effect of Infusion Method and Parameters on Solid Gain in Blueberries

In order to obtain optimal processing conditions for producing infused blueberries with high solid gain, we investigated the infusion characteristics of blueberries under various processing parameters in sugar solutions with 1:1 ratio of solution and berries. Static batch constant concentration infusion and dynamic batch infusion (DBI) were tested as the alternative operations for the traditional static batch infusion. The studied parameters were solution temperature (25 to 70 °C), concentration (20 to 70°Brix), and types of osmotic agent (fructose, dextrose, polydextrose, sucrose, maltodextrin, and corn syrup). The results showed that high solid gain can be achieved by maintaining high and constant concentration of infusion solution at high temperature with dynamic infusion. For DBI, high temperature and high solution concentration resulted in fast and high solid gain. The rate of water loss increased with an increase in solution temperature and concentration. To obtain high quality sugar-infused products with high product yield, a DBI process of 50 °C and 50°Brix sugar infusion is recommended, which could have solid gain of 1.65 g/g after a 5-h infusion. Polydextrose showed higher solid gain than sucrose when infusion time was longer than 180 min, although it had lower solid gain in short-term infusion.

Statistical Thermodynamics and Ordering Kinetics of D0&lt;sub&gt;19&lt;/sub&gt;-Type Phase: Application of the Models for H.C.P.-Ti–Al Alloy

Using the self-consistent field approximation, the static concentration waves approach and the Onsager-type kinetics equations, the descriptions of both the statistical thermodynamics and the kinetics of an atomic ordering of D019 phase are developed and applied for h.c.p.-Ti–Al alloy. The model of order–disorder phase transformation describes the phase transformation of h.c.p. solid solution into the D019 phase. Interatomic-interaction parameters are estimated for both approximations: one supposes temperature-independent interatomic-interaction parameters, while the other one includes the temperature dependence of interchange energies for Ti–Al alloy. The partial Ti–Al phase diagrams (equilibrium compositions of the coexistent ordered α2-phase and disordered α-phase) are evaluated for both cases. The equation for the time dependence of D019- type long-range order (LRO) parameter is analyzed. The curves (showing the LRO parameter evolution) are obtained numerically for both temperature-independent interaction energies and temperature-dependent ones. Temperature dependence of the interatomic-interaction energies accelerates the LRO relaxation and diminishes a spread of the values of instantaneous and equilibrium LRO parameters versus the temperature. Both statistical-thermodynamics and kinetics results show that equilibrium LRO parameter for a non-stoichiometry (where an atomic fraction of alloying component is more than 0.25) can be higher than for a stoichiometry at high temperatures. The experimental phase diagram confirms the predicted (ordered or disordered) states for h.c.p.-Ti– Al.

Atomic-Ordering Kinetics and Diffusivities in Ni–Fe Permalloy

Using the static concentration waves’ method and self-consistent-field approximation, the Onsager-type kinetics equation is solved to describe the L12-type long-range order (LRO) relaxation. To calculate the diffusivities for Permalloy, the experimental diffraction data in respect to LRO-parameter evolution for Ni3Fe are used. Theoretical curves of a time-dependent LRO for Ni– Fe are plotted. Dilution of alloying element (with a deviation from stoichiometry) results in deceleration of the LRO-parameter history (at the initial evolution stage) and in an increase of its relaxation time. Both statistical-thermodynamics and kinetics results show: at high temperatures, equilibrium LRO parameter for non-stoichiometric Permalloys can be higher than for stoichiometric one.

Diffusion Mechanisms in Nanocrystalline and Nanolaminated Au-Cu

Thermal anneal treatments are used to identify the temperature range of the two dominant diffusion mechanisms – bulk and grain boundary. To assess the transition between mechanisms, the low temperature range for bulk diffusion is established utilizing the decay of static concentration waves in composition-modulated nanolaminates. These multilayered structures are synthesized using vapor deposition methods as thermal evaporation and magnetron sputtering. However, at low temperature the kinetics of grain-boundary diffusion are much faster than bulk diffusion. The synthesis of Au-Cu alloys (0-20 wt.% Cu) with grain sizes as small as 5 nm is accomplished using pulsed electro-deposition. Since the nanocrystalline grain structure is thermally unstable, these structures are ideal for measuring the kinetics of grain boundary diffusion as measured by coarsening of grain size with low temperature anneal treatments. A transition in the dominant mechanism for grain growth from grain boundary to bulk diffusion is found with an increase in temperature. The activation energy for bulk diffusion is found to be 1.8 eV·atom-1 whereas that for grain growth at low temperatures is only 0.2 eV·atom-1. The temperature for transitioning from the dominant mechanism of grain boundary to bulk diffusion is found to be 57% of the alloy melt temperature and is dependent on composition.

What comes first, the zebra finch or the egg: temperature-dependent reproductive, physiological and behavioural plasticity in egg-laying zebra finches

Avian reproduction is generally timed to synchronize chick-rearing with periods of increased food abundance. Consequently, the energetically demanding period of egg production may coincide with periods of lower food availability, fluctuating temperature and more unstable weather. Little is known about the physiological mechanisms underlying temperature-induced variation in egg production. We therefore examined the influence of low ambient temperature (7 degrees C vs 21 degrees C) on reproductive output (e.g. egg mass, clutch size, laying interval, laying rate), daily food consumption and lipid variables in zebra finches Taeniopygia guttata. When faced with egg production at 7 degrees C, laying zebra finches increased energy intake by 12.67 kJ day(-1), and were thus able to maintain body condition (e.g. body mass, fat and muscle score) and circulating triacylglyceride at levels comparable to those at 21 degrees C. However, when producing eggs at 7 degrees C, females took longer to initiate egg laying (6.5 vs 6.1 days at 21 degrees C), and ultimately laid fewer eggs (5.5 vs 6.0 eggs) at a slower rate (0.90 eggs day(-1) vs 0.95 eggs day(-1)). These temperature-related declines in reproductive output were accompanied by decreases in modal (from 36.6 at 21 degrees C to 24.3 nm at 7 degrees C) and median very low density lipoprotein (VLDL) particle diameter (from 29.6 to 26.4 nm) and in the proportion of VLDL particles that were capable of passing through the pores in the ovary to access the developing ovarian follicles (i.e. particles with diameters between 25 and 44 nm; from 45.90% to 32.55%). However, variation in reproductive output was not related to any static concentration or structural measure of VLDL. Therefore, other temperature-dependent mechanisms must be involved in the physiological processes that regulate reproductive output of passerine birds at low ambient temperatures.

Flow Rate and Fluence Rate Dependences of the Triplet-State Lifetime of Talaporfin Sodium Photochemical Reaction in Flowing Solution

The flow rate and fluence rate dependences of the triplet-state lifetime (τT) and singlet oxygen (1O2) luminescence intensity of a Talaporfin sodium (mono-L-aspartyl chlorin e6, Laserphyrin®) photochemical reaction in a flowing solution were studied. The oxygen consumption rate constant (k) did not proportionally increase as the fluence rate increased. The relationship between the static oxygen concentration in the flowing solution and τT was estimated. τT at the fluence rate of 0.8×104 W/m2 was 16% longer than that at 0.2×104 W/m2 at the same oxygen concentration. The τT increase at the high-fluence rate is attributed to local and temporal oxygen depletion. The local and temporal oxygen depletion might cause the fluence-rate dependence nonproportionality of the measured k.