Cast Deposition Research Articles

Nasal cast deposition for xylo- and oxymetazoline formulations using two different nasal pumps

Background: Allergic rhinitis, rhinosinusitis, and upper respiratory tract infections, including the common cold, are caused by inflammation of nasal cavity areas. A key symptom is nasal congestion, which can be relieved with nasal spray medications. A key goal in developing a nasal spray medication delivery device for the relief of nasal congestion is delivering a fine mist to the inflamed areas while providing user comfort and convenience. Methodology: Using a Koken nasal cast model, we studied the deposition patterns of 2 xylometazoline and 1 oxymetazoline for- mulations with 2 different nasal pumps, the currently marketed Freepod and the investigational laterally actuated device. Effects of nasal tip orientation and breathing were investigated. Additionally, the degree of xylometazoline and oxymetazoline dripping down the back of the cast was assessed. Results: The largest coverage overall was observed with the xylometazoline formulation with the laterally actuated pump and without breath simulation. The laterally actuated pump used at a 30° angle resulted in deposition to the inferior, middle, and superior turbinates of the nasal cast, with less variability than the Freepod. Drippage at the back of the cast was observed with the Freepod device but not with the laterally actuated device. Conclusions: Using a nasal cast model, the laterally actuated pump used at a 30° angle produced a full mist covering areas inflamed with the common cold, allergic rhinitis, and rhinosinusitis with no dripping at the back of the cast, an improvement compared with the Freepod pump. In vivo studies are needed to confirm nasal cast results.

Fluorescence-enabled evaluation of nasal tract deposition and coverage of pharmaceutical formulations in a silicone nasal cast using an innovative spray device

IntroductionThe characterisation of nasal formulations is a critical point. However, there are still no recommendations or guidelines in terms of standard approaches for evaluating the formulation's nasal deposition and/or coverage profile. This study optimises a method for quantifying silicone nasal cast deposition and coverage of liquid formulations using different nasal devices. ObjectivesThe present work investigates the nasal deposition and coverage patterns of innovative nasal spray nozzles producing slow velocity soft mists, using a nasal cavity replica and a fluorescent dye. MethodsThe study of the deposition pattern of a fluorescent liquid formulation in a transparent nasal cast was carried out in both the presence and absence of a simulated inhalation flow. The extent of the deposition pattern was investigated using ImageJ and fluorescence in the nasal cast, quantified by fluorometric analysis. The particle size distribution and initial droplet velocity were determined using a laser diffractometer and a high-speed camera with a frame rate of 1000 fps. ResultsA uniform intranasal coverage was obtained with droplets of a volume median particle size (Dv50) between 15 and 25 µm in airflow between 10 and 30 L/min. In these conditions, aerosol formulations can be uniformly deposited in the vestibule and turbinate cavity nasal regions, with less than 10 % passing beyond the nasopharyngeal region. ConclusionThe method applied allowed for the determination of the coverage of the nasal cast in different regions using images analysis and fluorometric analysis. Droplet velocity is a critical parameter in the deposition in the nasal cavity. With standard swirl nozzles, many droplets are found on the surface of the nasal vestibule. Soft mist nozzles produce smaller droplets at a much lower initial velocity (<1 m/s), resulting in a more uniform coverage.

Serum and urine metabolomics analysis reveals the role of altered metabolites in patulin-induced nephrotoxicity

Various studies have identified the kidney as a target organ for patulin (PAT)-induced toxicity. However, detailed mechanistic insights into PAT-induced nephrotoxicity had not yet been done. Therefore, along with classical toxicological parameters, liquid chromatography-high resolution massed spectrometry (LC-HRMS) based metabolomics has been carried out to delineate the mechanism(s) of PAT-induced nephrotoxicity.An in vivo study was conducted using male Wistar rats, divided into three groups. PAT (25 µg/kg b.wt and 100 µg/kg b.wt) and, control were given through oral gavage, 5 days/week for 28 days. At the end of the experiment, changes in the mean body/ organ weight, food and water intake, expression of marker proteins of kidney injury, and histopathological changes were investigated. Furthermore, using LC-HRMS based metabolomics was performed on the serum and urine of PAT-exposed rats.The histopathological and toxicological analysis revealed a significant increase in glomerular mesangial cells, vacuolar degeneration, and cast deposition in the proximal convoluted tubules. The metabolomics showed metabolic perturbations in amino and fatty acid-related metabolic pathways in serum and urine of PAT-treated rats. In conclusion this study expands our understanding of PAT-induced metabolic alterations and its effects on renal function.

Effects of triangle grass decoction on bone metabolism in rats with chronic kidney disease complicated with mineral and bone abnormalities

Ethnopharmacological relevanceTriangle grass is a liliaceous Chlorophytum perennial herb of ChlorophytumlaxumR.Br. It is distributed mainly in Guangdong and Guangxi Provinces of China. The initial use of triangle grass was mainly to treat bone pain and swelling caused by a fall injury. Triangle grass tablets (NO. Z20070544) are also used as a preparation in our hospital because of their analgesic, anti-inflammatory, anti-snake venom and microcirculation improvement properties and other pharmacological effects (Mei et al., 2006). Triangle grass tablets have been widely used in our hospital to treat patients with bone pain from chronic kidney disease-mineral and bone disorder (CKD-MBD). However, the effects and mechanism of triangle grass on bone metabolism in chronic kidney disease complicated with mineral and bone abnormalities are unclear. Aim of the studyThe aim of the present study was to investigate the effects of a triangle grass decoction on bone metabolism in CKD-MBD rats. Materials and methodsCKD-MBD model rats were subjected to 5/6 nephrectomy combined with 0.5 g NaH2PO4/rat. Serum blood urea nitrogen (BUN), creatinine (Cr), phosphorus (P), calcium (Ca), and intact parathyroid hormone (iPTH) levels were measured with an automatic biochemical analyser. Bone mineral density was determined with a Viva CT 40 system. Bone morphogenetic protein 7(BMP-7),runt-related transcription factor 2 (Runx2) and Osterix protein levels were measured by Western blot analysis. Kidney, vertebra and thoracic aorta tissue samples were assessed by histopathology and immunohistochemistry (IHC). ResultsThe degrees of membrane thickening, necrosis, swelling and cast deposition were significantly reduced in high-dose rats and Low-dose rats. Serum BUN levels were significantly reduced in the Pre-H group (P < 0.05). Hypocalcaemia and hyperphos phataemia were detected in triangle grass (P < 0.05, P < 0.05). In addition, iPTH levels were significantly increased in the Pre-H group (P < 0.05). Alkaline phosphatase (ALP)levels were significantly decreased in the Pre-H group (P < 0.05). The bone mineral density was improved in the Pre-H and Pre-L groups. BMP-7 protein levels were significantly increased in the Pre-H group (P < 0.05). The pathological changes in muscle fibres in the thoracic aorta middle membranes were significantly alleviated in rats in the Pre-H and Pre-L groups. Changes in SM22α and SMα-act in protein levels were significantly attenuated in the Pre-H group (P < 0.05, P < 0.05). Changes in Runx2 and Osterix protein levels were also significantly attenuated in the Pre-H and Pre-L groups (P < 0.05, P < 0.05). ConclusionsTriangle grass can simultaneously ameliorate vertebral bone loss and abnormal calcification in the thoracic aorta. Triangle grass has a definite effect on bone metabolism disorder in CKD-MBD rats.

A Rational Ternary Design of P3HT/Insulating Polymers–CNTs/P3HT for the Enhanced Thermoelectric Performances

ABSTRACT This work shows the design and development of ternary layer thermoelectric composites based on semiconducting polymer P3HT, insulating polymers, and carbon nanotubes. The ternary layer composite film is prepared by a straightforward drop‒cast deposition. The design consists of sandwiching an insulating polymer‒CNTs layer between two layers of a semiconducting polymer P3HT. A systematic investigation is employed by optimizing various features including the type of insulating polymers and CNTs (SWNT vs. MWNT), and doping. The electrical conductivity of the doped ternary composites is improved up to 265 S cm−1, with minimal loss in the Seebeck coefficient, leading to power factors (PF) up to ~30 μW m−1 K−2, however electrical conductivity of single‒layer doped P3HT is only 39.1 S cm−1 with a PF of 7.6 μW m−1 K−2 at room temperature. The enhancement in the TE properties can be ascribed to the formation of more efficient charge transport between the layers due to the rearrangement of the polymer chains and the generation of more junctions at the interface during the sequential layer deposition. The results also reveal that this method gives n‒type materials from intrinsically p‒type P3HT, and it switches to p‒type after doping.

High photoresponse performance of self-powered n-Cu2O/p-CuI heterojunction based UV-Visible photodetector

Conventional rare and toxic materials still dominate the photodetector industry. Therefore, efficient photodetectors based on environmentally friendly and low-cost materials are a high priority area. Addressing this issue, an n-Cu2O/p-CuI heterojunction based photodetector was fabricated and characterised. The photodetector was synthesised via atmospheric pressure hydrothermal and drop cast deposition processes. The Cu2O/CuI heterojunction was structurally, morphologically and optically characterised using XRD, EDX, SEM, and UV – VIS, respectively. At zero bias, the photodetectors exhibited a high sensitivity of 2.355 × 105 and 7 × 103 for visible and UV light, respectively. The observed highest responsivity at 465 nm is 250 mA W−1. Further, the device showed a 2 nA cm-2 dark current with a fast rising and falling time of 582 and 817 μs, respectively. The long term ageing study showed that photodetector has a lifetime of more than four years. These results reveal that n-Cu2O/p-CuI photodetector is a favourable approach for affordable, environmentally friendly and high-performance UV/Visible photoelectronic applications.

A modified USP induction port to characterize nasal spray plume geometry and predict turbinate deposition under flow

There is currently no in vitro technique for assessing plume geometry of nasal sprays under airflow conditions. However, a majority of FDA approved nasal products recommend that patients inhale during actuation. Therefore, a reproducible in vitro test that measures plume angles under physiologically relevant inhalation flow rates would be useful. The purpose of this study was to adapt the recently described Plume Induction Port Evaluator (PIPE) apparatus for nasal sprays under flow and correlate these with nasal cast deposition patterns.Mass Median Plume Angles (MMPAs) of four nasal spray formulations with increasing viscosities were determined using the PIPE apparatus in the absence and presence of airflow. MMPAs were then correlated to drug deposition within 3D printed nasal casts using airflow. We evaluated different inhalation instructions obtained from the package insert of nasal products.MMPAs significantly reduced (narrower angles) when using flow for the three formulations with the lowest viscosities. An increase in the turbinate deposition was observed in the nasal casts when just one of the nostrils was closed during inhalation, except by the highest viscosity formulation. The turbinate deposition numerically correlated with changes in the plume angles observed using PIPE.

Pattern of renal pathology in fish from Al-Hassa waterways, Saudi Arabia

Pollution of aquatic environment is a great concern worldwide. The teleostean kidney is one of the first organ to be affected by contaminants in water. The aim of this study is to assess histological changes of Oreochromis niloticus kidney collected from spring canals in Al-Hassa, Saudi Arabia. We report histological alterations in the kidney tissue of fish collected from three sites, namely Al-Jawhariya (site #1), Um-Sabah (site #2) and Al-Khadoud spring (site #3). The histopathological studies revealed relative differences in the severity of organ lesions among the three sites. The overall results showed that kidney architecture of fish samples was markedly disrupted. The major symptoms were dilation of the glomerular capillaries, reduction of Bowman’s space, degeneration of tubular epithelium, tubule cast deposition, and accumulation of pigmented macrophages (i.e., melanomacrophages). The histological damage in the kidney of O. niloticus is an evidence of the poor environmental quality of these spring canals. It appears that these wetland areas are still threatened by human activities and environmental degradation.

Protective Effect of Withania coagulans Fruit Extract on Cisplatin-induced Nephrotoxicity in Rats.

Background:Fruits of Withania coagulans (Solanaceae) reported to possess several bioactive compounds as curative agents for various clinical conditions. Cisplatin is a chemotherapeutic drug to treat sarcomas, carcinomas, lymphomas, cervical cancer, germ cell tumors, etc. The major factor that limits its clinical use is its dose-dependent nephrotoxicity.Aim:To explore the nephroprotective effect of W. coagulans extract and its modulatory effects against cisplatin-induced nephrotoxicity and genotoxicity.Materials and Methods:W. coagulans fruit extract was quantitatively standardized with withaferin A using high-performance thin-layer chromatography. The subacute toxicity study was performed according to OECD guidelines in experimental rats. Nephrotoxicity in rats was induced by a single dose of cisplatin (6 mg/kg, intraperitoneal). Nephroprotective role of W. coagulans fruit extract at different doses had been evaluated. It includes quantification of serum kidney toxicity markers, renal tissue oxidative stress biomarkers and pro-inflammatory cytokines level, DNA fragmentation assay, and histopathological examination of renal tissue.Results:Withaferin A was found 3.56 mg/g of W. coagulans fruit extract. It significantly prevented the rise in serum urea and creatinine level and also preserve rat kidneys from oxidative stress and free radical induced DNA damage. Histopathological study showed extract treatment eliminates tubular swelling, cellular necrosis, and protein cast deposition in cisplatin treated kidney tissue. It averted the decline in glutathione content, activities of superoxide dismutase and catalase. These parameters were restored to near normal levels by extract in a dose of 400 mg/kg, per oral. Conclusion: It can be justified that W. coagulans possess dose dependent protective effect against cisplatin induced kidney damages, primarily through its free radical scavenging and anti inflammatory activitySUMMARY Authentication and standardization of Withania coagulans fruitsSubacute oral toxicity studyEvaluation of nephroprotective activity against cisplatin-induced nephrotoxicityDNA fragmentation assay and histopathological examination of kidney tissue in experimental rats. Abbreviations Used: WHO: World Health Organization, SOD: Superoxide dismutase, CAT: Catalase, HPTLC: High-performance thin layer chromatography, p.o.: Per.oral, i.p.: Intraperitoneal, TNF-α: Tumor necrosis factor-alpha, IL-1β: Interleukin 1-beta, IL-6: Interleukin-6

Comparison of soil macro-invertebrate communities in Malaysian oil palm plantations with secondary forest from the viewpoint of litter decomposition

Biodiversity decline in rapidly expanding oil palm plantations is of global concern. Many studies have demonstrated that fauna species diversity is lower in oil palm plantations than forests. However, information about the flow-on effects of these declines in species diversity on ecosystem functioning is scarce for oil palm plantations. Litter decomposition performed by soil organisms is a vital ecosystem function that regulates nutrient cycling and carbon sequestration. Some studies have found a high level of redundancy among litter decomposing species. In order to evaluate the effects of the conversion of forests to oil palm plantations on decomposition, we investigated the abundance and biomass of soil macro-invertebrates at sites in two oil palm plantations and a secondary forest in Malaysia. Biodiversity of soil macro-invertebrates were lower in the oil palm plantations than in the secondary forest. The abundance and biomass of surface–living litter transformers was lower in oil palm plantations than forest, probably due to the isolated piles of frond litter that occur in plantations, instead of the more continuous litter layer observed in forests. However, we found dense populations of wood (litter)–feeding termites in the thick rachises of fronds heaped on the ground surface. A pantropical earthworm species, Pontoscolex corethrurus, which buries the litter through cast deposition, abounded more in the oil palm plantations than in the secondary forest. These characteristics of soil macro-invertebrates have also been reported in other oil palm plantations. Thus, we conclude that the conversion of forests to oil palm plantations may reduce diversity of soil macro-invertebrates, increase the heterogeneity of macro-invertebrates distribution and decrease populations of some functional groups of soil macro-invertebrates. However, overall, forest conversion does not appear to have a negative impact on the decomposition process to a great extent, owing to the colonization of plantation sites by other groups of decomposer animals that are favored by disturbance and/or the great amount of localized input of fresh fronds pruned at the time of fruit harvesting.

Anti-LG3 Antibodies Aggravate Renal Ischemia-Reperfusion Injury and Long-Term Renal Allograft Dysfunction.

Pretransplant autoantibodies to LG3 and angiotensin II type 1 receptors (AT1R) are associated with acute rejection in kidney transplant recipients, whereas antivimentin autoantibodies participate in heart transplant rejection. Ischemia-reperfusion injury (IRI) can modify self-antigenic targets. We hypothesized that ischemia-reperfusion creates permissive conditions for autoantibodies to interact with their antigenic targets and leads to enhanced renal damage and dysfunction. In 172 kidney transplant recipients, we found that pretransplant anti-LG3 antibodies were associated with an increased risk of delayed graft function (DGF). Pretransplant anti-LG3 antibodies are inversely associated with graft function at 1 year after transplantation in patients who experienced DGF, independent of rejection. Pretransplant anti-AT1R and antivimentin were not associated with DGF or its functional outcome. In a model of renal IRI in mice, passive transfer of anti-LG3 IgG led to enhanced dysfunction and microvascular injury compared with passive transfer with control IgG. Passive transfer of anti-LG3 antibodies also favored intrarenal microvascular complement activation, microvascular rarefaction and fibrosis after IRI. Our results suggest that anti-LG3 antibodies are novel aggravating factors for renal IRI. These results provide novel insights into the pathways that modulate the severity of renal injury at the time of transplantation and their impact on long-term outcomes.

Poly(melamine-co-formaldehyde) methylated effect on the interface states of metal/polymer/p-Si Schottky barrier diode

The deposition technique and interface effect of polymeric molecules onto silicon surface is crucial topic for organic/inorganic hybrid technologies. In this study, the chemical structure of poly(4-vinyl phenol) (PVP) has been modified by cross-linked agent in solution for deposition onto p-Si surface. The poly(melamine-co-formaldehyde) methylated (PMF) has been used as a cross-linked agent for PVP polymeric molecules to apply spin cast deposition technique. The rectification ratio and interface states have been improved with PMF cross-link agent compared with only PVP polymeric layer. Some important diode parameters such as diode ideality factor (η), barrier height (ϕb), interface state density (Nss), series resistance (Rs) of the Au/PVP:PMF/p-Si structure were calculated from the current–voltage (I–V) characteristics. The ideality factor and barrier height were found to be 2.37 and 0.71. For the explanation of the deviation of ideality factor value from 1, the interface states has been investigated by the frequency dependent capacitance (C–f–V) and conductance (G–f–V) techniques at room temperature. It is found that the interface states and Rs which indicate the deviation of the ideality factor of Au/PVP:PMF/p-Si structure is strongly depended on bias voltage and frequency.

Human embryonic stem cell-derived mesenchymal cells preserve kidney function and extend lifespan in NZB/W F1 mouse model of lupus nephritis.

Adult tissue-derived mesenchymal stromal cells (MSCs) are showing promise in clinical trials for systemic lupus erythematosus (SLE). However, the inability to manufacture large quantities of functional cells from a single donor as well as donor-dependent variability in quality limits their clinical utility. Human embryonic stem cell (hESC)-derived MSCs are an alternative to adult MSCs that can circumvent issues regarding scalability and consistent quality due to their derivation from a renewable starting material. Here, we show that hESC-MSCs prevent the progression of fatal lupus nephritis (LN) in NZB/W F1 (BWF1) mice. Treatment led to statistically significant reductions in proteinuria and serum creatinine and preserved renal architecture. Specifically, hESC-MSC treatment prevented disease-associated interstitial inflammation, protein cast deposition, and infiltration of CD3+ lymphocytes in the kidneys. This therapy also led to significant reductions in serum levels of tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6), two inflammatory cytokines associated with SLE. Mechanistically, in vitro data support these findings, as co-culture of hESC-MSCs with lipopolysaccharide (LPS)-stimulated BWF1 lymphocytes decreased lymphocyte secretion of TNFα and IL-6, and enhanced the percentage of putative regulatory T cells. This study represents an important step in the development of a commercially scalable and efficacious cell therapy for SLE/LN.

Multi-layer PEDOT:PSS/Pd composite electrodes for hydrazine oxidation

In this paper, a simple and stable composite electrode PEDOT:PSS/Pd based on the intrinsically conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was fabricated by drop-casting. The preliminary formation of water dispersion of PEDOT:PSS with Pd nanoparticles was followed by multistep drop cast deposition for the formation of thin metal-polymer composite layers on glassy carbon electrode. The morphology of pristine and composite films as well as the size and distribution of Pd particles were characterized by scanning electron microscopy. The electrochemical properties of composite metal-polymer layers were examined by cyclic voltammetry and chronoamperometry in solution of 0.2 M phosphate buffer solutions (PBS) in the presence and absence of hydrazine. It was demonstrated that electrocatalytical oxidation of hydrazine takes place only on electrochemically accessible palladium particles, located on surface or near-surface layers of composite film. The proposed multi-layer electrodes exhibited a wide linear range of response towards hydrazine detection (from 0.4 to 100 μM) and low detection limit of 0.12 μM (S/N = 3).

Caffeic acid, a phenol found in white wine, modulates endothelial nitric oxide production and protects from oxidative stress-associated endothelial cell injury.

IntroductionSeveral studies demonstrated that endothelium dependent vasodilatation is impaired in cardiovascular and chronic kidney diseases because of oxidant stress-induced nitric oxide availability reduction. The Mediterranean diet, which is characterized by food containing phenols, was correlated with a reduced incidence of cardiovascular diseases and delayed progression toward end stage chronic renal failure. Previous studies demonstrated that both red and white wine exert cardioprotective effects. In particular, wine contains Caffeic acid (CAF), an active component with known antioxidant activities.Aim of the studyThe aim of the present study was to investigate the protective effect of low doses of CAF on oxidative stress-induced endothelial injury.ResultsCAF increased basal as well as acetylcholine—induced NO release by a mechanism independent from eNOS expression and phosphorylation. In addition, low doses of CAF (100 nM and 1 μM) increased proliferation and angiogenesis and inhibited leukocyte adhesion and endothelial cell apoptosis induced by hypoxia or by the uremic toxins ADMA, p-cresyl sulfate and indoxyl sulfate. The biological effects exerted by CAF on endothelial cells may be at least in part ascribed to modulation of NO release and by decreased ROS production. In an experimental model of kidney ischemia-reperfusion injury in mice, CAF significantly decreased tubular cell apoptosis, intraluminal cast deposition and leukocyte infiltration.ConclusionThe results of the present study suggest that CAF, at very low dosages similar to those observed after moderate white wine consumption, may exert a protective effect on endothelial cell function by modulating NO release independently from eNOS expression and phosphorylation. CAF-induced NO modulation may limit cardiovascular and kidney disease progression associated with oxidative stress-mediated endothelial injury.

Non-trophic effects of earthworms on enchytraeids: An experimental investigation

Lumbricids and enchytraeids are two keystone fauna groups strongly responsible for the functioning of detrital food webs in temperate soils but acting at contrasting spatial scales. The relationships between both groups are poorly understood: considering their close kinship and trophic habits as generally microbi-/saprovores, competitive interactions are expected. However, due to engineering activities, various non-trophic earthworm impacts on enchytraeids also play a role, which has never been evaluated. We experimentally simulated and quantitatively estimated the effects of major non-trophic earthworm activities (burrowing, cast deposition, mucus release) and, in addition, of earthworm mortmass decay on the abundance of enchytraeids. Effects of two earthworm species belonging to epigeic (Lumbricus rubellus) and endogeic (Aporrectodea caliginosa) ecological groups were tested.Non-trophic earthworm effects strongly varied (a) between the types of activity (burrowing, casts, mucus), (b) across the soil profile, (c) between the earthworm species. In general, enchytraeids responded positively to earthworm non-trophic activities. Mucus release and burrowing showed usually stronger impacts than cast deposition. The participation of different non-trophic effects in the resulting joint effect (burrowing + casts + mucus) varied with earthworm species and soil horizon. Decomposition of dead earthworms stimulated enchytraeid abundance at lower, but inhibited it at higher mortmass amount.A comparison between enchytraeid responses to live earthworm (integrated trophic and non-trophic activities) and joint non-trophic (burrowing + casts + mucus) impacts allowed an approximate separation of both activity types. Rates of trophic and non-trophic impacts were quantitatively comparable and earthworm species-specific. In particular, L. rubellus and A. caliginosa earthworms rendered adverse (negative and positive, respectively) influence on enchytraeid abundance. It was concluded that the negative effects of live L. rubellus on enchytraeids were primarily related to its trophic activity, whereas the positive effects of live A. caliginosa were strongly connected with its non-trophic activities.

Influence of TiO2 nanoparticles on the optical and structural properties of PPV thin films converted at low temperatures

In this work we studied the optical properties of poly(p-phenylene vinylene) (PPV) produced by the thermal con- version of a precursor polymer blended with a synthetic dye (Reactive Black 5). The production of PPV by this method decreases the overall time and cost of the process. We observed that the introduction of the dye resulted in an additional absorbance band near 550-700 nm, which can be beneficial to the photon harvesting capacity of the polymer if it is used as the donor material in a photovoltaic device. We studied how the optical and structures properties of this blend change when different quantities of TiO2 nanoparticles are introduced. For that, thin films were produced by the cast deposition of pre- PPV:dye:TiO2. The scanning electronic microscopic images showed that the inorganic semiconductor form large agglomer- ates of approximately 200 nm, indicating a very rough surface where the dye can be adsorbed. The analysis of photolumi- nescence and Raman peaks indicated a reduction of the mean conjugation length of the polymer chains in the presence of TiO2 nanoparticles.

Effect of land use change, cropping systems and soil type on earthworm cast production in West and Central Africa

Data on earthworm surface cast deposition in undisturbed, cropped and recovering sites from West and Central Africa were compiled to assess the effects of land use system (LUS) change and if casting can be used to indicate soil quality.Annual cast deposition in undisturbed systems was significantly higher on Alfisols (49,000 kg ha−1) than on Ultisols (25,000 kg ha−1). Vegetation clearance had significant detrimental effects on earthworm activity. With an increasing length of continuous cropping, cast deposition declined. In young fallows, cast production exceeded levels attained in previously un-cropped controls on Alfisols, yet, on Ultisols, it depended on the previous LUS and length of the previous cropping phase. Recovery was highest after agrisilviculture and after clearing bush fallow. After forest clearance, burning and one year cropping, cast deposition did not recover within three years. On Alfisols, cast production was higher under planted tree fallow and natural fallow than under herbaceous fallow. On Ultisols, fallow type had no effect.Earthworm surface cast production contributes to soil quality. However, its suitability as an indicator of soil quality is limited to rough assessments as it is dependent upon earthworm species composition, vegetation management and soil type, with more drastic changes on the poorer Ultisols than the more fertile Alfisols.

Leaf litter acceptance and cast deposition by peregrine and endemic European lumbricids (Oligochaeta: Lumbricidae)

In Central Europe a rich endemic earthworm fauna exists. The ecology of most of these species has not been studied. In laboratory mesocosms we examined leaf litter acceptance and cast deposition of a total of 30 species, 21 of which were endemic. In both experiments earthworms, especially small species, exhibited a variety of behaviors. Hornbeam litter was consumed at higher C/N values by anecic species, but some epigeics still did not accept it. Surface cast deposition varied between 0 and 100% among small endogeics. Most anecic species deposited their casts belowground, but the model anecic species, Lumbricus terrestris was an exception: 79% of its total cast was deposited on the surface. Epigeics and endogeics did not clearly separate in these behavioral traits. Refinement of ecological categorization of Lumbricidae needs to include data on lesser known species.

Using X-ray tomography to quantify earthworm bioturbation non-destructively in repacked soil cores

X-ray tomography is used increasingly to study the macroporosity resulting from earthworm activity. However, macropores are not the only features visible on the images; other zones resulting from bioturbation by earthworms can be detected due to differences in greylevels. Four different soil cores were incubated with two earthworm species at two different densities (4 or 8 adults of the endogeic species Allolobophora chlorotica or 2 or 4 adults of the anecic species Aporrectodea nocturna). A fifth core without earthworms was used as a control. After six weeks, the cores were analysed by X-ray tomography using a medical scanner. The 3D earthworm burrow systems were reconstructed and a new and specific algorithm was used to determine other bioturbated zones (BZ) that were physically influenced by the earthworms. Expected differences in the structure of the burrow systems between the endogeic and anecic species were observed: the A. chlorotica burrows were narrower and more numerous, more branched and less vertical. When the earthworm density doubled, the volume and length of the A. chlorotica burrow system increased whereas no increase was observed for A. nocturna. The BZ, which were located in the upper section of the cores, represented almost the same volume as the macropores. These zones tended to be located further from the burrows in the A. chlorotica cores: 50% of the voxels corresponding to BZ were at a distance greater than 4 and 5.5 mm from the closest macropore for A. nocturna and A. chlorotica, respectively. Three processes may have contributed to form these zones, which are characterised by increased soil density: (i) soil compaction around the burrows during burrow creation, (ii) cast deposition in the burrows (burrow backfilling) and (iii) crushing of casts on the burrow walls (so called cutanes). The longer distance between BZ and macropores in A. chlorotica cores suggests that the proportion of burrow backfilling is higher for the endogeic species compared to the anecic species. If we assume that BZ located further than 10 mm from any burrow are actually burrows backfilled with casts, the volume of burrow backfilled in our study ranged from 14 to 18% for A. chlorotica and from to 8 to 10% for A. nocturna.