Clearance Rate Of Particles Research Articles

Adding fish waste to the diet of Iceland scallop Chlamys islandica: effects on feeding and reproductive ability

Organic enrichment from fish farming may impact benthic species and habitats in adjacent areas. Norwegian salmon farming is continuously growing, but, due to area conflicts and severe sea-lice problems in the western areas, growth of the industry is focused in the northern areas. Knowledge is scarce on how an increase in fish farming will impact Arctic and subarctic species and habitats. One such species is the Iceland scallop Chlamys islandica, distributed from the Lofoten Islands in Nordland County to the Varangerfjord in Troms and Finnmark County. To study the impact of fine-particle fish faeces on feeding and reproductive ability in adult Iceland scallop, particles <41 µm of finfish waste were added to the diet. Effects were tested via short-term (weeks) feeding studies using 2 diets, 100% cultured algal species and a 50% mix of algae and fish waste. In addition, a 100% fish waste diet was used to study longer-term effects on reproductive ability (months). Feeding (% particle clearance and feeding rate) on the microalgae diet tended to be higher than that on the diet containing fish waste, but the difference was significant only in 2 out of 4 cases. We did not find any effect of diets on reproductive ability (gonad development and fatty acid profiles) of scallops. Lack of knowledge on sufficient food levels for gonad maturation in this species may have affected the results. We suggest that future work includes the transplant of scallops from a reference site to fish production sites and that investigations begin immediately after spawning early in scallop gonad development.

Derivation of first-order dissolution rates to estimate particle clearance and burden in the human respiratory tract

Inhalation is a portal-of-entry for aerosols via the respiratory tract where particulate burden accumulates depending on sites of particle deposition, normal clearance mechanisms, and particle solubility. The time available for dissolution of particles is determined by the balance between the rate of particle clearance from a region and their solubility in respiratory solvents. Dissolution is a function of particle surface area divided by particle volume or mass (i.e., dissolution is inversely proportional to the physical diameter of particles). As a conservative approach, investigators commonly assume the complete and instantaneous dissolution of metals from particles depositing in the alveolar region of the respiratory tract. We derived first-order dissolution rate constants to facilitate biokinetic modeling of particle clearance, dissolution, and absorption into the blood. We then modeled pulmonary burden and total dissolution of particles over time as a function of particle size, density, and solubility. We show that assuming poorly soluble particle forms will enter the blood as quickly as highly soluble forms causes an overestimation of concentrations of the compound of interest in blood and other extrapulmonary tissues while also underestimating its pulmonary burden. We conclude that, in addition to modeling dose rates for particle deposition into the lung, physiologically based pharmacokinetic modeling of pulmonary and extrapulmonary tissues concentrations of moderately and poorly soluble materials can be improved by including estimates of lung burden and particle dissolution over time.

Exploring the potential mechanism of Yixiang capsule immune-enhancing function based on Network Pharmacology, Molecular docking, and Animal function experiment.

The Yixiang capsule with traditional Chinese herbs Cistanches Herba, Hedysarum multijugum Maxim,Fructus Ligustri Lucidi,and Fructus lycii are the main raw materials in a modern herbal medicine preparation containing corresponding bioactive ingredients after extraction and processing. This study aimed to investigate the immune-enhancing function of the Yixiang capsule and explore its potential mechanism. After oral administration of the Yixiang capsule to mice for 30 days, the spleen lymphocyte transformation activity, NK cell activity, DTH, macrophage phagocytosis, HC50 value, amounts of antibody-producing cells, carbon particle clearance rate, spleen, and thymus index were determined to evaluate the regulation effect of the Yixiang capsule on immune function. The potential mechanism underlying the immune-enhancing function of the Yixiang capsule was studied based on network pharmacology and molecular docking. The results showed that the Yixiang capsules can obviously increase the HC50 values in all groups, significantly enhance the DTH reaction of mice, the carbon clearance function in medium and high dose groups,and the phagocytic function of macrophages in high dose groups, but had no significant effect on NK cell activity, T lymphocyte proliferation, body weight and immune organ weight of mice. A total of 78 compounds of the Yixiang capsule may affect 123 metabolic pathways and 1022 GO terms by regulating 232 targets, such as the cancer signaling pathway ad the signal pathways of response to lipopolysaccharide, and the key targets predicted could stably bind to the core active components of the Yixiang capsule. These results suggested that the Yixiang capsule could enhance the immune function of mice and have the characteristics of a multi-component and multi-target synergistic effect on the enhanced immunity function, which provides the basis for the follow-up study.

Passage of exogeneous fine particles from the lung into the brain in humans and animals.

There are still significant knowledge gaps in understanding the intrusion and retention of exogeneous particles into the central nervous system (CNS). Here, we uncovered various exogeneous fine particles in human cerebrospinal fluids (CSFs) and identified the ambient environmental or occupational exposure sources of these particles, including commonly found particles (e.g., Fe- and Ca-containing ones) and other compositions that have not been reported previously (such as malayaite and anatase TiO2), by mapping their chemical and structural fingerprints. Furthermore, using mouse and invitro models, we unveiled a possible translocation pathway of various inhaled fine particles from the lung to the brain through blood circulation (via dedicated biodistribution and mechanistic studies). Importantly, with the aid of isotope labeling, we obtained the retention kinetics of inhaled fine particles in mice, indicating a much slower clearance rate of localized exogenous particles from the brain than from other main metabolic organs. Collectively, our results provide a piece of evidence on the intrusion of exogeneous particles into the CNS and support the association between the inhalation of exogenous particles and their transport into the brain tissues. This work thus provides additional insights for the continued investigation of the adverse effects of air pollution on the brain.

Role of endogenous incretins in the regulation of postprandial lipoprotein metabolism.

Incretins are known to influence lipid metabolism in the intestine when administered as pharmacologic agents. The aggregate influence of endogenous incretins on chylomicron production and clearance is less clear, particularly in light of opposing effects of co-secreted hormones. Here, we tested the hypothesis that physiological levels of incretins may impact on production or clearances rates of chylomicrons and VLDL. A group of 22 overweight/obese men was studied to determine associations between plasma levels of glucagon-like peptides 1 and 2 (GLP-1 and GLP-2) and glucose-dependent insulinotropic polypeptide (GIP) after a fat-rich meal and the production and clearance rates of apoB48- and apoB100-containing triglyceride-rich lipoproteins. Subjects were stratified by above- and below-median incretin response (area under the curve). Stratification yielded subgroups that differed about two-fold in incretin response. There were neither differences in apoB48 production rates in chylomicrons or VLDL fractions nor in apoB100 or triglyceride kinetics in VLDL between men with above- vs below-median incretin responses. The men with above-median GLP-1 and GLP-2 responses exhibited higher postprandial plasma and chylomicron triglyceride levels, but this could not be related to altered kinetic parameters. No differences were found between incretin response subgroups and particle clearance rates. We found no evidence for a regulatory effect of endogenous incretins on contemporaneous chylomicron or VLDL metabolism following a standardised fat-rich meal. The actions of incretins at pharmacological doses may not be reflected at physiological levels of these hormones.

Impact of Intertidal Distribution on the Physiological Performance of the Filter-Feeder Bivalve Perumytilus purpuratus (Bivalvia, Mytilidae) from Southern Chile

Intertidal animals experience reduced feeding times and differentiated respiratory capacity associated with aerial exposure, the duration of which depends on their location within the intertidal zone. Perumytilus purpuratus is a sessile mussel that forms dense mats in the rocky mid-intertidal in southern Chile. For this species, we documented the impact of different times of aerial exposure (3 and 6 h) on rates of oxygen consumption and feeding, according to their vertical location (upper and lower limits) within the intertidal zone. Mean oxygen consumption rates in air for individuals located in the upper intertidal zone were 52% higher than those of individuals located at the lower limits of their intertidal distribution. Additionally, individuals from the lower intertidal region always presented higher rates of oxygen consumption and particle clearance rates (58% higher and 18% higher, respectively) during immersion compared to individuals collected from the upper limit of their intertidal distribution, regardless of the duration of previous aerial exposure. Although we found no significant habitat-related differences in the relationship between shell length and gill surface area, individuals sampled from the lower intertidal zone were 8% heavier in dry tissue weight than individuals with the same shell lengths collected from of the upper limit of their intertidal distribution. Our results suggest that the individuals of this species near the upper limits of their intertidal distribution can probably compensate (e.g., higher absorption rate) for the reduced time that they have available for clearance, which might help them to avoid a major energetic disadvantage.

Study on the Enhancement of Immune Function of Astaxanthin from Haematococcus pluvialis.

This study was aimed at investigating the effect of astaxanthin on the immune function and its safety in mice. It was administered once daily at low, medium and high doses (4.2, 8.35, 16.70 mg/kg BW) to mice for 30 days. Subsequently, the spleen and thymus index, spleen lymphocyte transformation activity, delayed allergy reaction, amounts of antibody-producing cells, half-hemolytic value HC50, carbon particle clearance rate, macrophage phagocytosis, and natural killer cell (NK) activity were determined. Acute oral toxicity and genotoxicity tests were conducted to evaluate the safety of astaxanthin. Compared with the control group, medium and high doses of astaxanthin significantly increased the proliferation and transformation activities of spleen lymphocytes, activities of antibody-producing cells, serum hemolysin levels, and carbon particle clearance rate in mice (phagocytic index). High doses significantly improved delayed allergy reaction and NK cell activity. Results of acute oral toxicity and genotoxicity tests were negative. Gross anatomical observations and histopathological examination showed no abnormal changes associated with the treatments. In the article, it is confirmed that astaxanthin treatments significantly improve immune functions and show no toxic effects in the experimental doses.

Examining effects of surfactants on particle clearance rate and capture efficiency of the blue mussel Mytilus edulis

Suspension-feeding bivalve molluscs perform important ecological roles by coupling pelagic and benthic systems during their feeding activities. Particle capture, and thus feeding, is dependent on particle encounter and retention on the gill filaments, with several factors influencing this process. Over the past 30 yr, different types of synthetic microspheres have been used to examine aspects of particle capture and ingestion by bivalves. Critics of this work have posited that manufactured particles may contain surfactants, chemicals commonly used in manufacturing to reduce surface tension, that could produce spurious capture and ingestion rates. The goal of this work was to experimentally assess whether the presence of different types of surfactants on manufactured polystyrene particles can result in instantaneous effects on particle capture by the blue mussel Mytilus edulis. The effects of 3 different types of common surfactants (sodium dodecyl sulfate, benzalkonium chloride, Triton-X) on clearance rates (CR) and capture efficiencies (CE) were tested. Results indicated that none of the surfactant treatments had an effect on CR. Treatment with one of the surfactants (Triton-X) significantly lowered CE for 3 µm sized spheres compared to the control spheres (Milli-Q treated). None of the other tested surfactants significantly affected CE when compared to the control treatment. These data add to an understanding of particle handling by bivalves, and suggest that concentrations of surfactants found on commercially available microspheres used for experiments or found in the environment have little immediate effect on feeding processes.

A second order accurate approximation for fractional derivatives with singular and non-singular kernel applied to a HIV model

In this manuscript we examine the CD4+ T cells model of HIV infection under the consideration of two different fractional differentiation operators namely Caputo and Caputo-Fabrizio (CF). Moreover, the generalized HIV model is investigated by considering Reverse Transcriptase (RT) inhibitors as a drug treatment for HIV. The threshold values for the stability of the equilibrium point belonging to non-infected case are calculated for both models with and without treatment. For the numerical solutions of the studied model, we construct trapezoidal approximation schemes having second order accuracy for the approximation of fractional operators with singular and non-singular kernel. The stability and convergence of the proposed schemes are analyzed analytically. To illustrate the dynamics given by these two fractional operators, we perform numerical simulations of the HIV model for different biological scenarios with and without drug concentration. The studied biological cases are identified by considering different values of the parameters such as infection rate, growth rate of CD4+ T cells, clearance rate of virus particles and also the order of the fractional derivative.

Studies on the immunoregulation of Ginseng radix et rhizoma rubra aqueous extract in mice

Objective To investigate the immune enhancement effect of red ginseng aqueous extract in mice. Methods The aqueous extract of red ginseng was obtained by water extraction and concentration, and the aqueous extract 10 ml was equivalent to raw material 2.86 g. The experiment was divided into the blank control group, low dose group of red ginseng aqueous extract 0.24 g/(kg•d), middle dose group 0.48 g/(kg•d) and high dose group 1.43 g/(kg•d). In order to explore the immunoregulation effect of red ginseng aqueous extract, Organ/body weight ratio measurement, the delayed type hypersensitivity (DTH) reaction, the spleen lymphocyte transformation experiment induced by Con A, the detection of antibody-producing, the determination of serum hemolysin experiments, the clearance rate of carbon particles, the phagocytosis effect of macrophages with chicken red blood cell experiments, and the determination of natural killer cell activity were carried out with the mice. Results Compared to the blank control group, the tow edema degree (0.62 ± 0.14 mm, 0.53 ± 0.12 mm vs. 0.36 ± 0.10 mm) of low dose group and medium dose group significantly increased (P<0.05). The ability of proliferation of T lymphocytes (0.173 ± 0.054, 0.189 ± 0.063 vs. 0.098 ± 0.012) of low dose group and high dose group significantly increased (P<0.05). The number of haemolytic empty spots (137.49×103 ± 24.73×103, 148.43×103 ± 27.53×103vs. 112.96×103 ± 26.28×103) of medium dose group and high dose group significantly increased (P<0.05). The phagocytosis rate (35.67% ± 3.82%, 49.26% ± 6.54%, 57.92% ± 7.36% vs. 24.34% ± 4.22%) and index (0.72 ± 0.23, 0.82 ± 0.15, 0.91 ± 0.26 vs. 0.35 ± 0.11) of low-, medium-, high-dose group significantly increased (P<0.05). However, there was no statistical difference in the organ/body weight ratio of the experimental animals, the determination of serum hemolysin experiments, the clearance rate of carbon particles, and NK cells activity. Conclusion Red ginseng aqueous extract has an exact role in immunity improvement in mice. Key words: Ginseng radix et rhizoma; Ginseng radix et rhizoma rubra; Immunoregulation; Mice

Evaluation of the Cytotoxicity and Immune and Subacute Toxicity of Camptothecin-loaded Nanoparticles

CPT-loaded NPs with polyethylene glycol shells can increase its solubility in water and remain in circulation for a long time. This experiment has evaluated cytotoxicity and immune and subacute toxicity of CPT NPs. Camptothecin (CPT) was incorporated into biotin-F127-PLA or F127-PLA polymeric nanoparticles; a dialysis method was used for non-targeted CPT NPs and anti-CA125 antibodies for targeted CPT NPs. A cytotoxicity test was also conducted based on the growth inhibition of the mouse fibroblast-like L-929 cell line. The effects of the two CPT-loaded NPs on immunity were also determined through a carbon particle clearance rate assay. Each mouse was intraperitoneally injected with 0.4 ml/20 g.bw nanoparticles for 28 consecutive days in the subacute toxicity test. Results have showed that CPT NPs have reduced the toxicity of free CPT on the L-919 cells. The CPT NPs did not induce phagocytosis in the normal mice. At the end of subacute toxicity study no difference was found between the CPT NP and control groups in blood parameter analysis and main organ weight visceral coefficients. These results suggested that the new CPT NPs might elicit low toxic effects at cellular and organism levels.

Dredging-induced turbid plumes affect bio-irrigation and biogeochemistry in sediments inhabited by Lanice conchilega (Pallas, 1766)

Abstract Building man-made structures in coastal seas are often preceded by dredging operations, inducing turbid plumes of suspended sediment. To study the effects of such high-concentration sediment plumes on the suspension-feeding polychaete Lanice conchilega, a laboratory experiment was performed, in which individuals of L. conchilega were exposed to natural seawater with a suspended sediment concentration (SSC) of ∼ 0.3 g l−1 and treatments with elevated SSC of 5 and 1 g l−1, representing concentrations in a dredging plume at the moment of sediment release and after initial dilution, respectively. We measured clearance rates of sediment particles, biogeochemical fluxes, and bio-irrigation. While clearance rates and nitrite efflux significantly increased in both treatments with elevated SSC compared with the control, bio-irrigation increased at 1 g l−1 but was lowest at 5 g l−1. It is suggested that piston pumping is intensified under intermediate concentrations to remove sediment, but ceases under high concentrations are due to sediment ingestion. By transporting oxygen into the sediment, bio-irrigation enhances aerobic microbial processes, among which nitrification. We conclude that short-term extreme suspended sediment concentrations can have a significant impact on the biogeochemistry of the seabed through changes in behaviour of L. conchilega.

Hypertonic saline has a prolonged effect on mucociliary clearance in adults with cystic fibrosis

BackgroundInhaled hypertonic saline (HS) has been shown to increase mucociliary clearance (MCC) and improve clinical outcomes in adults and adolescents with cystic fibrosis (CF). However, in younger children with CF, a large study failed to demonstrate clinical benefits. This discrepancy could reflect pharmacodynamic differences in the MCC response to HS in different populations. We previously demonstrated the absence of a sustained effect of HS on MCC in healthy adults and in this study sought to characterize the durability of the MCC response to HS in adults with CF. MethodsAt two study sites, MCC was measured in CF adults using gamma scintigraphy during three separate visits: at baseline, 15 min, and 4 h after a single dose of HS (7% NaCl, 4 mL). Particle clearance rates at these visits were used to assess the durability of the MCC response to HS. ResultsThe average 90-minute clearance rate measured 4 h after HS was significantly increased (21.81% ± 12.8) when compared to baseline (13.77% ± 8.7, p = .048) and showed no apparent slowing relative to the rate measured 15 min after HS. While not all subjects responded to HS, the acute response strongly predicted the sustained effect in these subjects (r = 0.896, p < .0001). ConclusionsThese results suggest that, in contrast to healthy adults, a single dose of HS has a prolonged effect on MCC in adults with CF, which lasts at least 4 h. This may explain its clinical efficacy in this population.

Evaluation of toxicity of Deepwater Horizon slick oil on spat of the oyster Crassostrea virginica.

The 2010 explosion of the Deepwater Horizon (DWH) oil rig generated the largest marine oil spill in US history with millions of barrels of crude oil released in the Gulf of Mexico (GoM). The eastern oyster, Crassostrea virginica, is an ecologically and economically important species in the northern GoM. Due to its biological characteristics (sessile, filter feeding), juvenile oysters may have been affected. This study investigated the effects of surface-collected DWH oil prepared as high-energy water-accommodated fraction (HEWAF) on the survival of 2-month-old oyster spat, and evaluated the potential impacts of HEWAF on particle clearance rate and spat tissue. Exposure of oysters to a range of oil/HEWAF (0-7-66-147-908-3450μg tPAH50 (sum of 50 polycyclic aromatic hydrocarbons)L-1) resulted in non-dose-dependent mortalities and reduced clearance rates of algal food (Tisochrysis lutea). A morphometric study of the digestive tubules (DGTs) indicated a dose-dependent response to oil exposure on lumen dilation, on epithelium thinning of the DGT, and a significant change in DGT synchrony (LOEC=66μg tPAH50L-1). This finding suggests that structural changes occurred in the digestive gland of exposed oysters most likely due to an oil-related stress. In addition, histological observations showed that tissues in contact with HEWAF (gills, palp, connective tissue, digestive gland) were adversely impacted at ≥ 7μg tPAH50L-1, and exhibited pathological symptoms typical of an inflammatory response (e.g., hemocyte diapedesis and infiltration, syncytia, epithelium sloughing).

Settling of dilbit-derived oil-mineral aggregates (OMAs) & transport parameters for oil spill modelling

The size and settling velocity of oil-mineral aggregates (OMAs) derived from diluted bitumen are primary constituents in predictive models for evaluating the potential fate of oil spilled in the aquatic environment. A series of low sediment concentration (15mg·L−1), colder water (<10°C) wave tank experiments designed to measure variability in these parameters in naturally-formed OMAs in response the presence or absence of chemical dispersant are discussed. Corresponding lab experiments revealed settling velocities of artificially formed OMAs on the order of 0.1–0.4mm·s−1. High-resolution imagery of settling particles were analyzed for particle size, density and settling velocity. In situ formation of OMAs in the wave tank was unsuccessful. Possible effects of chemical dispersant on natural sediment flocculation, the size of suspended oil droplets and clearance rates of suspended particles are discussed.

The Mayak Worker Dosimetry System (Mwds-2013): Plutonium Dissolution in The Lungs-An Analysis of Mayak Workers.

Lung doses resulting from inhalation of plutonium aerosols are highly dependent on the assumed rate of particle clearance, which occurs by two competing processes: (1) particle transport clearance to the alimentary tract and to the thoracic lymph nodes and (2) clearance to systemic tissues, which occurs by dissolution of particles in lung fluid followed by uptake to blood, which is a process collectively known as absorption. Unbiased and accurate estimates of the values of lung absorption parameters are required to obtain reliable estimates of lung dose, particularly those inferred from urine bioassay. Parameter values governing the rate of absorption are best estimated from data, such as autopsy measurements of plutonium in the lungs and systemic tissues, which directly relate to the exposed workers of interest. However, because the mathematical models that determine clearance from the lungs and systemic tissues are complex and consist of many parameters, estimates of model parameter values are subject to significant uncertainties. With this in mind, this paper uses a Bayesian approach to estimate one of the most important dissolution parameters: the slow rate of dissolution. This is estimated for both plutonium nitrate and plutonium oxide bearing aerosols in the lungs of former workers of the Mayak Production Association. A value of 2.6 × 10-4 d-1 is estimated for plutonium nitrates, and 4.7× 10-5 d-1 for plutonium oxides.

Clearance rates of residual stone fragments and dusts after endoscopic lithotripsy procedures using a holmium laser: 2-year follow-up results.

To investigate the spontaneous clearance rates of remnant particles following miniaturized percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS). Among 624 patients who underwent mini-PCNL or RIRS at our institution from 2011 to 2015, we collected data of 247 patients with 2years of follow-up. Of these, we included 148 patients with unilateral renal stones between 10 and 30mm, as well as remnant particles after surgery. The size criteria of dusts and residual fragments (RFs) were, respectively, <1 and <3mm. After excluding 22 patients, 126 patients (RFs=21, dusts=98, and both RFs and dusts=7) were analyzed. Mean age was 56.5 (±14.4) years, and mean stone size was 19.5 (±12.5) mm. The mean follow-up period was 18.5 (±12.9) months. In patients whose remnant particles were naturally eliminated following lithotripsy, the mean stone passage time was 9.0 (±9.3) months in the dusts and 13.9 (±11.1) months in the RFs groups (P=0.135). Remnant particles disappeared in 42 out of 105 patients (40.0%) in dusts and 7 out of 28 patients (25.0%) in RFs groups (P=0.187). The size of dusts and RFs increased, respectively, in 18.1% (19/105) and 28.6% (8/28) of patients with remnant particles during the follow-up period. The presence of dusts and RFs was poor prognostic factors in patients underwent renal stone surgery using a holmium laser. Complete residual stone removal by using a basket or dusts eradication by irrigation for an adequate time during surgery can be a good surgical strategy.

Inhalation of Bacterial Cellulose Nanofibers Facilitates Silica Particle Clearance in a Rat Silicosis Model

Background: Millions of workers globally are afflicted by pneumoconiosis, a disease caused by inhaling dust or particles. A particularly prevalent form is silicosis, caused by inhaling silica particles. The Chinese herbal medicine kombucha, which contains Gluconacetobacter xylinus and yeasts, can effectively clear dust from rats’ lungs. The study presented here assessed the potential effectiveness of inhalable bacterial cellulose nanofibers (IBCNs) prepared from G. xylinus cultures for facilitating clearance of silica particles in a rat silicosis model. Methods: For this purpose, 50 mg portions of silica dust were injected into lungs of rats, which were subsequently exposed to IBCNs for a month. The treatment’s effects were then evaluated by examining the extent and severity of histopathological lesions in the animals’ lungs, analyzing gas contents of blood samples, and determining organ coefficients, lung collagen contents, lungs’ dry and wet weights, silica particle clearance rates, and both numbers and types of cells in lung lavage fluid. Results: IBCN inhalation was found to relieve the detrimental effects of silica exposure and facilitated silica particle clearance in a rat silicosis model. Unexpectedly, our results also indicated that saline inhalation also strongly stimulates silica particle clearance from rat lungs. Conclusions: These results provide the first evidence for a functional effect of IBCN inhalation in a rat silicosis model, indicating that bacterial cellulose nanofiber inhalation can facilitate silica particle clearance. Further studies are required to determine whether these effects are mediated by IBCN and define the mechanisms involved. The findings also indicate that salt water may effectively clear dust from lungs, thereby alleviating risks of silicosis and reducing risks associated with haze and smog.

Development of Man-rGO for Targeted Eradication of Macrophage Ablation.

This study was aimed to develop and evaluate a smart nanosystem that targeted photothermal ablation of inflammatory macrophages in atherosclerotic plaque. Mannosylated-reduced graphene oxide (Man-rGO) was synthesized using three step procedures: (1) preparation of ox-GOs, (2) microwave-assisted synthesis of PEI-rGOs, and (3) mannosylation of PEI-rGO using reductive amination reaction (Man-rGOs). The ζ-potential of Man-rGO that signifies electrophoretic mobility of the charged surface was examined using Zetasizer Nano ZS. The effects of Man-rGO on the cell viability was evaluated using LDH assay and AlamarBlue assay. The targeting efficacy of Man-rGO was assessed using the cellular uptake rate by M2-polarized (i.e., which is induced by IL-4) macrophage. The effects of NOMela loaded in Man-rGO on the enhancement of phagocytosis were evaluated by examining the phagocytic clearance rate of zymosan-FITC particles. The microwave-assisted reduction of GOs was adapted for a facile synthesis of polyethylenimine-reduced GO (PEI-rGO). The mannose functionalization (Man-rGO) of PEI-rGO produced a greater number of amide linkages formed by reductive amination reaction between PEI-rGO and mannose. The ζ-potential of PEI-rGO was +30.6 ± 3.3 mV, whereas that of Man-rGO was down to +13.1 ± 3.8 mV upon interaction with mannose mainly due to the conjugation of mannose on the PEI-rGO surface. Near-infrared (NIR) irradiation increased the temperature of Man-rGO solution to around 45 °C, suggesting that Man-rGO is more potent than ox-GO or rGO in photothermal ablation activity triggered by NIR laser irradiation (808 nm). All testing formulations at the concentrations up to 10 μg/mL exerted less than 10% of membrane disintegration. For AlamarBlue study, more than 90% of cell viability were maintained at the concentrations (up to 10 μg/mL) of all tested formulations. The fluorescent microscopy images of cells after 1 h incubation demonstrated that Man-rGO were mainly accumulated at the subcellular level where the mannose receptors were overexpressed. The cell viability of macrophages significantly decreased upon exposure to Man-rGO irradiated with NIR, but no changes were observed from that of mast cells (for mast cells, 98.3 ± 0.3%; for macrophages, 67.8 ± 1.3%, p < 0.01), indicating that Man-rGO achieved enhanced targetability toward mannose receptor mediated cellular uptake. N-Nitrosomelatonin (NOMela) loaded in macrophage exerted enhanced phagocytic activity. It was concluded that the enhanced photothermal ablation activity of Man-rGO triggered by NIR laser irradiation was mediated through their targetability toward overexpressed mannose receptor, a marker of M2-phenotype of macrophage. The results of this study supported that Man-rGO can serve as an efficient platform for the targeted therapy against atherosclerosis.

Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa

South Africa lacks a commercial oyster hatchery. To inform the sourcing of seed for future hatchery establishments, we compared half-sib Pacific oyster Crassostrea gigas cohorts from hatcheries in Namibia and Chile. We measured oyster growth, mortality, condition and feeding organ morphology in Algoa Bay (AB, Eastern Cape) and Saldanha Bay (SB, Western Cape), South Africa, from July 2011 to June 2012. Within SB, 14.3% of mean daily sea temperatures exceeded this species’ thermal optimum of 19 °C, compared to 50.5% in AB. Food abundance (mean daily chlorophyll a concentration) in SB (7.8 mg m–3) was double that in AB (3.9 mg m–3) where, presumably to increase particle clearance rates in a relatively phytoplankton-poor environment, oysters had larger gill:palp surface area ratios. Plankton fatty acid profiles (indicators of food quality) differed between locations. In AB, instantaneous growth rates differed between cohorts, and trends varied seasonally. Within both locations, condition index was usually higher in Chilean oysters, whereas shell density was higher in Namibian oysters. In AB only, Chilean seed suffered substantially higher summer mortalities than Namibian seed, suggesting that the latter are more suited to temperatures in AB. AB should also be assessed for culture of the indigenous oyster species that occur there.