Initial Amount Research Articles

The effect of initial inoculation amount of microalgae on synergistic purification of biogas slurry

ABSTRACT In this study, Chlorella and Scenedesmus were inoculated in biogas slurry medium with initial inoculum (OD680) of 0.05, 0.1, 0.2, and 0.3, respectively, and 5% CO2 was continuously injected. The study aimed to examine the carbon sequestration capacity of Chlorella and Scenedesmus, as well as the effectiveness of removing pollutants such as TN, TP, and COD in biogas slurry medium. Additionally, an economic efficiency analysis of energy consumption was conducted. The group with an initial inoculum (OD680) of 0.3 for both types of microalgae exhibited better tolerance to pollutants, entered the logarithmic growth stage earlier, promoted nutrient removal, achieved higher energy efficiency, and reduced carbon emissions compared to the other groups. The highest carbon sequestration rates were 18.03% for Chlorella and 11.05% for Scenedesmus. Furthermore, Chlorella demonstrated corresponding nutrient removal efficiencies of 83.03% for TN, 99.84% for TP, and 90.06% for COD, while Scenedesmus exhibited removal efficiencies of 66.35% for TN, 98.74% for TP, and 77.71% for COD. The highest energy efficiency for pollutants and CO2 removal rates for Chlorella were 49.51 ± 2.20 and 9.91 ± 0.44 USD−1, respectively. In conclusion, the findings demonstrate the feasibility of using microalgae for simultaneous purification of biogas and biogas slurry.

О возможности синтеза β-“ядра” полиоксимолибдата железа (III) в водных растворах

This work describes for the first time the conditions for synthesizing a stable form of β-"core" iron (III) polyoxymolybdate (POM) in aqueous solutions in the form of a new molecular ("nuclear") state in a monomeric state. The optimal conditions for the formation of iron (III) POMs were determined from the light absorption of the product of the interaction of molybdate with iron (III) cations in the ultraviolet region of the spectrum. The range of light absorption of POM iron (III), kinetics and optimal acidity concerning changes in acidity, molybdate ion and exposure time after its quantitative formation were established. It has been shown that POM of iron (III) is formed at pH 3.4÷5.4, with the ratio of initial amounts ν (FeIII) :ν (MoVI) = 1:6 and is stable up to 96 hours. It has been established for the first time that, under the developed optimal conditions, iron(III) POM forms a complex associate with a low water solubility with six associated crystal violet (CV) cations, forming a very low water soluble complex associate. The obtained data indicate the formation of a new “β-core” of iron(III) POM with the composition (OH)6[H3FeMo6O18].

Yeast Lipids from Crude Glycerol Media and Utilization of Lipid Fermentation Wastewater as Maceration Water in Cultures of Edible and Medicinal Mushrooms

Four wild “red” yeast strains (Rhodosporidium kratochvilovae FMCC Y70, R. toruloides NRRL Y-27013, R. toruloides NRRL Y-17902 and R. toruloides NRRL Y-6985) were cultured in shake flasks on industrial glycerol at an initial substrate (Gly0) concentration ≈ 50 g/L under nitrogen limitation. Strains NRRL Y-27013, NRRL Y-17902 and NRRL Y-6985 presented appreciable dry cell weight (DCW) and lipid synthesis (DCW up to 18–19 g/L containing lipids in quantities ≈ 47%, w/w). Strains NRRL Y-27013 and NRRL Y-6985 were further tested in higher Gly0 concentrations (≈90 g/L and ≈110 g/L) with the same initial nitrogen quantity as in the first (“screening”) experiment. Both strains, despite the high Gly0 concentrations and C/N ratios (up to 120 moles/moles) imposed, presented significant DCW production (up to c. 29.0–29.5 g/L). Yeast biomass contained significant lipid (42–43%, w/w) and endopolysaccharide (up to 42%, w/w) quantities. Both lipids and endopolysaccharide quantities (in % w/w) noticeably increased as a response to the imposed nitrogen limitation. Lipids containing mainly oleic and palmitic acids constituted ideal candidates for biodiesel synthesis. Thereafter, the wastewaters derived from the lipid production process (lipid fermentation wastewaters—LFWs) were used as maceration waters in cultivations of edible and medicinal fungi, where novel (non-conventional) substrates were used in the performed cultures. CW (coffee residue + wheat straw), CB (coffee residue + beech wood shavings), OW (olive crop + wheat straw), OB (olive crop + beech wood shavings), RW (rice husk + wheat straw) and RB (rice husk + beech wood shavings) were soaked/sprayed with LFWs or tap water and utilized in the cultivation of Pleurotus, Ganoderma and Lentinula mushrooms. The impact of LFWs on the mycelial growth rate (mm/d) and biomass production was evaluated. The results show that regardless of the wetting method, the highest growth rates (6.2–6.6 mm/d) were noticed on RW and RB for Pleurotus eryngii and Ganoderma resinaceum, on OW, OB and RW for Ganoderma applanatum and on RW, OW and OB for Lentinula edodes. Nevertheless, high biomass production was obtained on substrates soaked with LFWs for Pleurotus ostreatus (RW: 443 mg/g d.w.), L. edodes (RB: 238 mg/g d.w.) and Ganoderma lucidum (RW: 450 mg/g d.w.). Overall, this study demonstrates the possibility of the industrial conversion of low-value agro-waste to mycelial mass and eventually to important food products.

Investigation into the effects of different recycled magnetic additives on anaerobic co-digestion of sludge and straw

The addition of magnetic additives has been found to enhance the anaerobic co-digestion of sludge and straw. Due to strong magnetic properties, these additives can be easily separated from the digestate, allowing for recycling during the continuous anaerobic digestion process. This study aimed to investigate the impact of different recycled magnetic additives (specifically, magnetic biochar and Fe3O4) on the anaerobic co-digestion of sewage sludge with corn straw. The results showed that the addition of recycled Fe3O4 with an initial amount of 10 g/kg resulted in the highest cumulative methane yield of 295.70 mL/g VSadded, which increased by 79.81% as compared to the control. The results suggest that magnetic biochar with higher carbon content exerts a more noticeable impact on shortening the digestion lag phase time, as indicated by kinetic analysis. With the addition of recycled Fe3O4, the Methanosaeta and Methanosarcina enhanced significantly. Especially Methanosarcina, which was increased from 3.85% to 6.28%, resulting in a 2.43% increase. Furthermore, the predominant aceticlastic pathway of digestion process was consolidated, and the enriched Methanosarcina broadened the pathways of methanogenesis. This research provides a potential utilization strategy of recycling Fe3O4 for accelerating the anaerobic degradation of urban and rural areas solid waste.

Self-similar behavior of successive Coulombic fissions of evaporating charged water droplets

Charged droplets suspended in an electrodynamic balance experience a form of instability known as Coulombic fission when electric forces (resulting from the electrical charges on the droplet surface) surpass surface tension forces. For a pure-fluid droplet with a given diameter, a charge limit (known as Rayleigh limit, qR) exists at which Coulombic Fission occurs. In an evaporating droplet with a certain initial amount of charge (q), the Rayleigh limit is reached when the droplet decreases to a certain smaller diameter due to evaporation. During Coulombic fission, the droplet releases some of the charges and returns to a stable state. Further evaporation will lead to the next Rayleigh limit. As a result, several successive Coulombic fissions may occur during the evaporative lifetime of a droplet. In this study, charged, sub-millimeter droplets of deionized water were suspended using an electrodynamic balance and left to evaporate into their surroundings. As many as 15 Coulombic fissions were observed during the evaporation of a single droplet. The time of evaporation and droplet diameter at Coulombic fissions were recorded using high-speed imagery and digital image processing. The amount of charge at the time of each fission was calculated based on droplet size and Rayleigh limit. It was found that during each fission, the droplet releases about 14 % of its charge. Results indicated that droplets with similar initial relative charge (q/qR) sustained Coulombic fissions at similar normalized diameters independently of initial droplet size and evaporation rate. As a consequence of this, and in accordance with the d2-law of pure-fluid droplet evaporation, the times at which Coulombic fissions occur during the droplet's lifetime can be predicted for a given initial droplet size and evaporation rate.

Ultrasound-assisted adsorption of organic dyes in real water samples using zirconium (IV)-based metal-organic frameworks UiO-66-NH2 as an adsorbent

The utilization of dye adsorption through metal-organic frameworks represents an eco-friendly and highly effective approach in real water treatment. Here, ultrasound assisted adsorption approach was employed for the remediation of three dyes including methylene blue (MB), malachite green (MG), and congo red (CR) from real water samples using zirconium(IV)-based adsorbent (UiO-66-NH2). The adsorbent was characterized for structural, elemental, thermal and morphological features through XRD, XPS, FTIR, thermogravimetric analysis, SEM, BET , and Raman spectroscopy. The adsorption capacity of adsorbent to uptake the pollutants in aqueous solutions was investigated under different experimental conditions such as amount of UiO-66-NH2 at various contact durations, temperatures, pH levels, and initial dye loading amounts. The maximum removal of dyes under optimal conditions was found to be 938, 587, and 623 mg g−1 towardMB, MG, and CR, respectively. The adsorption of the studied dyes on the adsorbent surface was found to be a monolayer and endothermic process. The probable mechanism for the adsorption was chemisorption and follows pseudo-second-order kinetics. From the findings of regeneration studies, it was deduced that the adsorbent can be effectively used for three consecutive cycles without any momentous loss in its adsorption efficacy. Furthermore, UiO-66-NH2 with ultrasound-assisted adsorption might help to safeguard the environment and to develop new strategies for sustainability of natural resources.

Thermal stability prediction of frozen rocks under fluctuant airflow temperature in a vertical shaft based on finite difference and finite element methods

There are abundant coal resources in the permafrost regions of the Qinghai-Tibet Plateau. Open-pit mining is the primary method for coal extraction due to its simple technology and cost-effectiveness. However, the mining process can lead to degradation in permafrost regions. Underground coal mining has been adopted as an option to minimize the impact on the permafrost environment. However, underground coal mining in permafrost regions, along with ventilation, can disrupt the thermal equilibrium of frozen rocks around the shaft, leading to changes in the permafrost table and the seasonal thawed layer around the shaft. Therefore, it is necessary to predict the temperature field of frozen rocks under mine ventilation. Some researchers focus on the temperature of frozen rocks in respect to constant airflow temperature. In fact, the airflow temperature in the shaft varies related to shaft depth, ground temperature, ventilation amount, and ventilation time. In this study, we utilize field data to construct two numerical models for predicting the temperature regime of frozen rocks. The first model, using the finite difference method, describes airflow temperature in the shaft within permafrost regions, accounting for variations in shaft depth, ground temperature, initial rock temperature, ventilation time, and ventilation amount. A fitting equation is then determined as a third boundary condition. The second model employs the finite element method to solve the heat transfer equation with phase change. The results indicate that the maximum thaw depth of frozen rocks around the shaft of Jiangcang coal mine ranged from 3.25 to 5.3 m at various shaft depths. This maximum thaw depth occurs on September 15th and is correlated with ventilation time, stabilizing after three years. Natural ventilation offers protection to frozen rocks around the shaft, and these results can serve as references for designing support systems in underground mining within permafrost regions.

An efficient separation for fluoride-ions from water supplies by ion precipitate flotation: Pilot scale study with generation of coagulative bubbles

Bubble surface modification is a promising technique that enables to increase the efficiency of a treatment that aims to remove a certain particle with lower consumption of chemical inputs. In this study, the so-called coagulative bubbles were generated from a mixed system consisting of amphoteric surfactant (Cocamidopropyl betaine, CAPB) and inorganic polymer coagulants (aluminum sulfate and calcium chloride) for the removal of fluoride ions present in groundwater destined for human supply. The critical micellar concentration (CMC) of CAPB was 0.26 mmol L−1. The coagulant bubbles (CB) were generated from pressurizing the coagulant solution in distilled water and applied continuously in a helical tubular reactor. The CB treatment method provided higher fluoride removal compared to conventional treatment with simple coagulant application. The CBs generated with Al made it possible to remove approximately 98 % of the initial amount of fluoride measured (3.5 mg L−1) with a dosage of 31 mg L−1 of Al; feed flow rate of 20 L min−1; pH 6 ± 0.5; and saturation pressure of 3 atm. This same operation, but without generation of CBs (regular atmospheric pressure), allowed the removal of 67 % of the initial fluoride concentration.

Controllable pH- and light-responsive chitosan-based multicomponent interpenetrating networks

Intelligent chitosan-based multivariate interpenetrating network (ICMIPN) was facilely tailor-made via modulating its components. ICMIPN was generated through common radical cross-linking reaction among macromonomers, which were derived from chitosan, starch and poly(vinyl alcohol) respectively, and acrylic acid (AA) as well as 4-acryloyoxyazobenzene (AHAB). ICMIPN exhibited a reversible trans-cis-trans photoisomerization behavior when it was subjected to alternative UV and visible light irradiation or dark storage. ICMIPN also displayed pH-sensitive swelling in buffer salines. By adjusting the initial amount of AHAB or AA, the responsive property of ICMIPN was varied accordingly. In addition, the thermal stability of ICMIPN was changed with altering its composition.

Analysis of Within-Host Mathematical Models of Toxoplasmosis That Consider Time Delays

In this paper, we investigate two within-host mathematical models that are based on differential equations. These mathematical models include healthy cells, tachyzoites, and bradyzoites. The first model is based on ordinary differential equations and the second one includes a discrete time delay. We found the models’ steady states and computed the basic reproduction number R0. Two equilibrium points exist in both models: the first is the disease-free equilibrium point and the second one is the endemic equilibrium point. We found that the initial quantity of uninfected cells has an impact on the basic reproduction number R0. This threshold parameter also depends on the contact rate between tachyzoites and uninfected cells, the contact rate between encysted bradyzoite and the uninfected cells, the conversion rate from tachyzoites to bradyzoites, and the death rate of the bradyzoites- and tachyzoites-infected cells. We investigated the local and global stability of the two equilibrium points for the within-host models that are based on differential equations. We perform numerical simulations to validate our analytical findings. We also demonstrated that the disease-free equilibrium point cannot lose stability regardless of the value of the time delay. The numerical simulations corroborated our analytical results.

Quantum Computing in Insurance Capital Modelling under Reinsurance Contracts

In this study, we design an algorithm to work on gate-based quantum computers. Based on the algorithm, we construct a quantum circuit that represents the surplus process of a cedant under a reinsurance agreement. This circuit takes into account a variety of factors: initial reserve, insurance premium, reinsurance premium, and specific amounts related to claims, retention, and deductibles for two different non-proportional reinsurance contracts. Additionally, we demonstrate how to perturb the actuarial stochastic process using Hadamard gates to account for unpredictable damage. We conclude by presenting graphs and numerical results to validate our capital modelling approach.

Influence of Si and Mo on the Sigma-Phase Precipitation in S32750 Super Duplex Stainless Steel Slab

In this study, we investigated the effect of Si and Mo on the sigma-phase precipitation in S32750 super duplex stainless steel slab. The activity for Mo with increasing Si and Mo was calculated by the Wagner formula, and the equilibrium solidification phase diagrams of S32750 duplex stainless steels with different Si and Mo contents were calculated using the thermo-calc software. The sigma phase precipitated mainly at ferrite/austenite phase boundaries and grew up towards the interior of ferrite phase in S32750 SDSS slab. The area fraction and size of the sigma phases significantly increased with increasing Mo content and Si content. Also, the increment in Mo and Si content affected the Mo concentration in sigma phase. The sample（Mo:3.4%,Si：0.3%） had a lowest sigma-phase area fraction of 2.84% and had lowest Mo content in σ phase.The calculation results showed that the increase of Mo and Si content increased the initial precipitation temperature and maximum precipitation amount of σ phase in S32750 SDSS equilibrium phase diagram. The activity of Mo also increased with increasing Si content and Mo content. That is, Mo and Si elements promoted the precipitation of σ phase.

Evolution of CT radiation dose in pediatric patients undergoing hybrid 2-[18F]FDG PET/CT between 2007 and 2021.

To evaluate the evolution of CT radiation dose in pediatric patients undergoing hybrid 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) PET/CT between 2007 and 2021. Data from all pediatric patients aged 0-18 years who underwent hybrid 2-[18F]FDG PET/CT of the body between January 2007 and May 2021 were reviewed. Demographic and imaging parameters were collected. A board-certified radiologist reviewed all CT scans and measured image noise in the brain, liver, and adductor muscles. 294 scans from 167 children (72 females (43%); median age: 14 (IQR 10-15) years; BMI: median 17.5 (IQR 15-20.4) kg/m2) were included. CT dose index-volume (CTDIvol) and dose length product (DLP) both decreased significantly from 2007 to 2021 (both p < 0.001, Spearman's rho coefficients -0.46 and -0.35, respectively). Specifically, from 2007 to 2009 to 2019-2021 CTDIvol and DLP decreased from 2.94 (2.14-2.99) mGy and 309 (230-371) mGy*cm, respectively, to 0.855 (0.568-1.11) mGy and 108 (65.6-207) mGy*cm, respectively. From 2007 to 2021, image noise in the brain and liver remained constant (p = 0.26 and p = 0.06), while it decreased in the adductor muscles (p = 0.007). Peak tube voltage selection (in kilovolt, kV) of CT scans shifted from high kV imaging (140 or 120kVp) to low kV imaging (100 or 80kVp) (p < 0.001) from 2007 to 2021. CT radiation dose in pediatric patients undergoing hybrid 2-[18F]FDG PET/CT has decreased in recent years equaling approximately one-third of the initial amount. Over the past 15 years, CT radiation dose decreased considerably in pediatric patients undergoing hybrid imaging, while objective image quality may not have been compromised.

Optimization of Brewer's Yeast Quantity in Liquid and Gel Larval Diets for the Mediterranean Fruit Fly.

Several artificial larval diets have been developed, evaluated and used for mass-rearing of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Teprhitidae). There are several efforts to reduce the cost of rearing and optimize the quality of the produced sterile males that are destined for release in sterile insect release programs. Survival, growth, longevity and reproductive capacity of sterile males are strongly connected with the most expensive ingredient, the brewer's yeast (protein), in the larval diet. The current study focused on settling the optimal content of brewer's yeast in a liquid diet and a gel diet. Egg hatch rates, developmental duration of immatures, pupation rate, pupae and adult survival were recorded as indicators of quantity and quality of the produced adults. Egg hatch was higher and larval developmental duration longer in the gel diet. In contrast to the liquid diet, an increase in brewer's yeast concentration was correlated with increased pupation rate and pupae survival in the gel diet. Reducing brewer's yeast up to 50% of its initial quantity had no significant effect on the survival of the emerging adults regardless of the diet type. Our findings may contribute to the production of low-cost and effective diets for use in mass-rearing facilities of medflies.

Study on modified VAc-VeoVa10 latex prepared by soap-free emulsion polymerization

Modified latex is prepared via the soap-free emulsion polymerization of ethyl acetate (VAc) and vinyl versatate (VeoVa10). DFHMA is used as modified monomers. The composite surfactants of SR-10 and ANPEO-10 are used as the composite emulsifiers. The polymerization is initiated by potassium sulfate (KPS). The structure of latex film was characterized by Fourier transform infrared spectroscopy (FTIR). The latex films were tested by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA) determinator. The particle size of the latex emulsion particle size is determined by the Zetatrac dynamic light scatter. Results show that the optimum condition of preparing the modified latex can be obtained, i.e. the amount of emulsifier is 4.0%; the mass ratio of SR-10 to ANPEO-10 is 1:1; the amount of initiator is 0.5%; the mass ratio ofVAc to VeoVa10 is 1:1; the amount of DFHMA is 5.0%. The appearance of the latex is blue and translucent with a small particle size. The conversion rate is more than 98%. Compared with the conventional latex, the hydrophobicity and heat resistance of the film have been improved. Moreover, the latex has good chemical stability and mechanical stability.

Effects of SiO2 particle surface design on the photocuring properties of interparticle photo-cross-linkable Pickering emulsions

This study aims to investigate the effects of particle surface structures of interparticle photo-cross-linkable w/o Pickering emulsions, designed for the rapid manufacturing of porous ceramic components, on their microstructures, light-curing behaviors, and moldability. The emulsions were designed by mixing SiO2/toluene suspensions stabilized by functional polyethyleneimine (PEI), which was partially complexed with oleic acid (OA) in various ratios (15–50 mol% to total EI units), small quantities of multifunctional acrylate (MA), photo-radical initiator, and water. When the OA content was low (15 mol%), a Pickering emulsion was produced that had a lower size distribution of the dispersed phase than the emulsions obtained when the OA content was high. Additionally, the successful shaping of porous SiO2 bodies by in-situ photocuring of the Pickering emulsion in a silicone mold followed by drying was achieved when the OA content was low. However, severe structural collapse of photocured bodies was observed during drying when the OA content was high (30 and 50 mol%). The higher quantities of reactive amines present on the particle surface played an important role in ensuring interparticle photo-cross-linking, maintaining the structure of photocured bodies against capillary forces during drying.

Characterization of enteric-coated erythromycin tablets by Raman mapping and its pharmaceutical evaluation.

Enteric tablet coating thickness is a critical quality attribute of the coating process that can affect dissolution behavior in vitro as well as release in vivo. Raman mapping offers unique advantages in analyzing the distribution of active pharmaceutical ingredients and excipients in formulations. In this study, Raman mapping was used to characterize the coating of enteric-coated erythromycin tablets coated by two different processes and compare the differences in their coating formulation, thickness, and uniformity. Furthermore, we aimed to select the appropriate pH of the dissolution medium at which the coating slowly cracks to release the drug and determine the dissolution profile. The differences in the coating thickness and uniformity of the two products resulted in differences in dissolution behavior. Although there are differences in the coating processes for the two types of enteric-coated erythromycin tablets, the thickness of the outer coating on the side is a critical quality attribute in both processes. The outer coating of product A is relatively thick, and the thickness of the outer coating on the side affects the dissolution amount. The outer coating of product B is relatively thin, resulting in a short cracking time and large variation and a significant difference in the initial dissolution amounts between tablets. Raman mapping can be used to analyze the differences in coating formulations and for process evaluation.

Effect of the scanning strategy and tribological conditions on the wear resistance of IN718 obtained by Laser Metal Deposition

Since the advent of additive manufacturing processes, new ways of repairing damaged parts emerged. Among those, Laser Metal Deposition offers the possibility of restoration or functionalization of surface properties. In this work, we study the wear properties of an IN718 coating deposited by LMD. IN718 is deposited according to several scanning strategies. Samples are subjected to dry flat-on-flat reciprocating wear tests using the flat surface of a cylindrical pin as a counter body. Then, we investigate the impact of the scanning strategy, the normal load, and the number of cycles on wear. Finally, we compare the wear resistance of the LMD samples with the one of wrought IN718 to evaluate the competitiveness of the wear properties of the material obtained by LMD. Results show that the scanning strategy turns out to not change the wear resistance of the deposited sample despite the highly heterogeneous surface microstructure. As the chosen contact is a flat-on-flat contact, the large area covered by the pin does not perceive the local microstructural heterogeneities. It has been observed as well that the wear volume of the coating increases linearly as the normal load increases, with an evolution of the wear mechanisms. Although oxidized transfer layer is observed at lower load, the main wear mechanisms observed are abrasion and adhesion. Then, by studying the wear evolution with increasing testing time, it has been observed that after a certain amount of cycles, a protective oxide layer appears and prevents IN718 from wear. In similar tribological conditions, wrought IN718 has slightly better wear resistance than its LMD's homolog. This difference in wear between the materials obtained by two processes could certainly be explained by the high initial amount of dislocations in the LMD samples and the presence of detrimental phases in its microstructure, such as Laves phases. Nonetheless, this study highlights the good wear resistance of the IN718 samples obtained by LMD despite their non-optimized as-built properties.

Aqueous Radical Initiated Oxidation of an Organic Monolayer at the Air-Water Interface as a Proxy for Thin Films on Atmospheric Aerosol Studied with Neutron Reflectometry.

Neutron reflectometry has been used to study the radical initiated oxidation of a monolayer of the lipid 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at the air-solution interface by aqueous-phase hydroxyl, sulfate, and nitrate radicals. The oxidation of organic films at the surface of atmospheric aqueous aerosols can influence the optical properties of the aerosol and consequently can impact Earth's radiative balance and contribute to modern climate change. The amount of material at the air-solution interface was found to decrease on exposure to aqueous-phase radicals which was consistent with a multistep degradation mechanism, i.e., the products of reaction of the DSPC film with aqueous radicals were also surface active. The multistep degradation mechanism suggests that lipid molecules in the thin film degrade to form progressively shorter chain surface active products and several reactive steps are required to remove the film from the air-solution interface. Bimolecular rate constants for oxidation via the aqueous phase OH radical cluster around 1010 dm3 mol-1 s-1. Calculations to determine the film lifetime indicate that it will take ∼4-5 days for the film to degrade to 50% of its initial amount in the atmosphere, and therefore attack by aqueous radicals on organic films could be atmospherically important relative to typical atmospheric aerosol lifetimes.

Caspofungin sequestration in a polyacrylonitrile-derived filter: Increasing the dose does not mitigate sequestration

Critically ill patients frequently require continuous renal replacement therapy. Echinocandins are recommended as first-line treatment of candidemia. Preliminary results suggested echinocandin sequestration in a polyacrylonitrile filter. The present study aimed at determining whether increasing the dose might balance sequestration. STX® filter, Baxter-Gambro was used. A liquid chromatography-mass spectrometry method was used for dosage of caspofungin. In vitro drug disposition was evaluated by NeckEpur® technology using a crystalloid medium instead of diluted/reconstituted blood, focusing on the disposition of the unbound fraction of drugs. Two concentrations were assessed. At the low dose, the mean measured initial concentration in the central compartment (CC) was 5.1 ± 0.6 mg/L. One hundred percent of the initial amount was eliminated from the CC within the 6-hour session. The mean total clearance from the CC was 9.6 ± 2.5 L/h. The mean percentages of elimination resulting from sequestration and diafiltration were 96.0 ± 5.0 and 4.0 ± 5.2%, respectively. At high dose, the mean measured initial concentration in the CC was 13.1 mg/L. One hundred percent of the initial amount was eliminated from the CC within the 6-hour session. The mean total clearance from the CC was 9.5 L/h. The mean percentages of elimination resulting from sequestration and filtration were 88.5 and 11.5%, respectively. Increasing the dose does not mitigate caspofungin sequestration in STX® filter. The results raise caution about the simultaneous use of caspofungin and polyacrylonitrile-derived filters. Intermittent modes of renal replacement therapy might be considered. For sensitive species, fluconazole might be an alternative.