Power extraction from ambient vibration

Autonomous devices such as sensors for personal area networks need a long battery lifetime in a small volume. The battery size can be reduced by incorporating micro-power generators based on ambient energy. This paper describes a new approach to the conversion of mechanical to electrical energy, based on charge transportation between two parallel capacitors. The polarization of the device is handled by an electret. A largesignal model was developed, allowing simulations of the behavior of any circuit based on this generator for any mechanical input signal. A small-signal model was derived in order to quantify the output power as a function of the design parameters. A layout was made based on a standard SOI-technology, available in a MPW. With this layout it is possible to generate 100 mW at 1200 Hz

Pharmacokinetics and pharmacodynamics of non-steroidal anti-inflammatory drugs in birds

The aims of this thesis were to investigate the pharmacokinetics and pharmacodynamics of non-steroidal anti-inflammatory drugs in birds. For decades, the inflammatory process and the properties of the NSAIDs have been extensively investigated in humans and other species. However, current knowledge on inflammation and anti-inflammatory drugs in birds is limited. Inflammation is a complex mechanism designed to protect the organism against different stimuli. NSAIDs act as inhibitors of the formation of certain mediators of inflammation, originating from the arachidonic acid cascade. In the general introduction, the literature is reviewed about the mechanism of action, the adverse reactions and the pharmacokinetics of non-steroidal anti-inflammatory drugs, and the possible indications for use of anti-inflammatory drugs in bird medicine. Due to the lack of information on NSAIDs in birds, most of the information about the mechanism of action and the adverse reactions are described based on the knowledge obtained in mammal species. In chapter 1.1., an overview about the main pharmacokinetic parameters and some bird specific anatomy and physiology is given. In chapter 2.1., the literature about the different aspects of inflammation in birds is reviewed: increased vascular permeability, leukocyte changes, acute phase proteins and inflammation mediators. On several occasions, a comparison with inflammation in mammals is made. Especially the acute phase of inflammation is described. Information on the pharmacokinetics of anti-inflammatory drugs in birds is scarce. Choice of drug and choice of dosage is usually empirical, since studies of antiinflammatory drugs are lacking. In chapter 1.2., the first experiments are described, three commonly used veterinary non-steroidal anti-inflammatory drugs (NSAIDs) were administered intravenously to five different bird species. Sodium salicylate, flunixin and meloxicam were selected as anti-inflammatory drugs. These NSAIDs were administered intravenously to chickens (Gallus gallus), ostriches (Struthio camelus), ducks (Cairina moshata), turkeys (Meleagris gallopavo) and pigeons (Columba livia). Plasma concentrations of the drugs were determined by validated high-performance liquid chromatography methods and pharmacokinetic parameters were calculated with compartment models. Also the plasma protein binding capacity of the different bird species for flunixin, meloxicam and salicylic acid at three different concentrations was studied. Most bird species exhibited a rapid elimination of these drugs. Ostriches had the fastest elimination rate for all three NSAIDs, but there were some interesting species differences. For salicylic acid, the half-life in pigeons was at least three to five times longer than the other bird species. Chickens had a half-life that was approximately ten times as long as the other bird species for flunixin and the half-life of meloxicam in chickens and pigeons was three times as long as for the other bird species. The plasma protein binding capacity for flunixin and meloxicam was moderate and showed a similar pattern for the different bird species. For salicylic acid more variation was seen between the species and pigeons exhibited a very low plasma protein binding capacity for salicylic acid. Several reasons for this difference in pharmacokinetic parameters are possible. Metabolism of these drugs can be species dependent. Therefore, the excretion pattern of sodium salicylate and its metabolites in chickens and pigeons was studied. This is described in chapter 1.3. An intravenous injection was made in these birds and the combined urinary and faecal droppings were collected at different time intervals. A marked difference was seen in the amino acid conjugation pattern of salicylic acid. Chickens used ornithine for conjugation and pigeons used glycine. Furthermore, the excretion of the glycine conjugate in pigeons was prolonged and in contrast to the ornithine conjugate in chickens, was not seen in the plasma. Based on preliminary information obtained in liver and kidney tissues of these species, it seems that the amino acid conjugation of salicylic acid with glycine in pigeons occurs only in the kidney and the amino acid conjugation of salicylic acid with ornithine in chickens occurs both in liver and in kidney. The pharmacodynamics of the NSAIDs in birds were studied in two inflammation models in chickens. In both models, sodium salicylate was used as NSAID, since this drug exhibited favourable pharmacokinetics in chickens and can be economically and practically interesting for use in poultry medicine. In chapter 2.2., an experiment where an acute inflammatory reaction was generated by implanting a carrageenan impregnated sponge strip in the subcutaneous tissue of broiler chickens is described. Half of the chickens received 50 mg/kg BW sodium salicylate orally and half received a placebo treatment. Blood and exudate samples were taken from these chickens at predetermined times. The pharmacokinetics of sodium salicylate were investigated in blood and exudate. Other parameters that were investigated were the volume of the exudate, the number of leukocytes in the exudate and the prostaglandin E2 concentration in the exudate. Also bradykinin was injected intradermally and the effects of sodium salicylate on bradykinin induced oedema were studied. Maximum salicylic acid plasma concentrations occurred within the hour after administration and maximum exudate levels were seen at the first exudate sampling point (4 h). Salicylic acid exudate concentrations exceeded plasma concentrations at the same time points and the exudate half-life was longer than the plasma half-life. No differences were found in the volume of the exudate and the leukocyte numbers between the treated and the untreated group. Sodium salicylate reduced the PGE2 concentration in the inflammatory exudate at the 4 hour time point, but at the later time points, no significant differences were found. The intradermally injected bradykinin did not produce significant effects in the chicken skin. Based on these findings, sodium salicylate may be used to suppress the inflammatory cascade in chickens, but further research is needed to characterise the inflammatory response in this chemical inflammation model and the actions of this non-steroidal antiinflammatory drug in chickens. In chapter 2.3., the last set of experiments are described. An acute phase reaction in broiler chickens was provoked through the intravenous injection of Escherichia coli lipopolysaccharide. Two experiments were set up with sodium salicylate to study the effects of this NSAID upon the LPS acute phase reaction. In the first experiment, different oral doses of sodium salicylate were given and the effect on body temperature was measured. Other inflammation indices, such as plasma corticosterone and ceruloplasmin levels, serum thromboxane B2 and zinc levels were also monitored during the experiment. In a separate experiment, food and water consumption and other behavioural parameters were studied. In the first experiment, a dose dependent attenuation of the fever response of the chickens in the salicylate treated groups was observed. Plasma corticosterone and ceruloplasmin levels rose and zinc and thromboxane B2 levels declined after an LPS injection. Except for thromboxane B2, no dose dependent differences after treatment with sodium salicylate were seen in these parameters. In the second experiment, the water intake, but not the food intake, was significantly higher in the salicylate treated group. No behavioural differences were seen between the positive control and the salicylate treated group. These data confirm that sodium salicylate is an effective antipyretic agent after injection of LPS in chickens, if used at an appropriate dosage. The general conclusions of this research after the pharmacokinetics and pharmacodynamics of NSAIDs in bird medicine are manifold : the investigated NSAIDs generally have a rapid half-life, but large species differences exist. The pharmacokinetics of other more practical administration routes need further research. The differences in metabolism may be a reason for the differences in pharmacokinetic parameters between the bird species. Salicylates have a clear antipyretic effect in chickens, but the mediation of avian inflammation and the influence of NSAIDs on disease and pain need further research

A microsensor array for biochemical sensing

A microsensor array to measure chemical properties of biological liquids is presented. A hybrid integration technique is used to mount four sensor chips on a micro flow channel: a pressure, temperature, pH, combined pO2 and pCO2 sensor chip. This results in a microsensor array which is developed to meet the technical requirements for space applications. The integration method allows to integrate other types of sensor chips. This multi-purpose and multi-user approach makes the microsensor array suitable for various biochemical applications

Congolese rhizospheric soils as a rich source of new plant growth-promoting endophytic Piriformospora isolates

In the last decade, there has been an increasing focus on the implementation of plant growth-promoting (PGP) organisms as a sustainable option to compensate for poor soil fertility conditions in developing countries. Trap systems were used in an effort to isolate PGP fungi from rhizospheric soil samples collected in the region around Kisangani in the Democratic Republic of Congo. With sudangrass as a host, a highly conducive environment was created for sebacinalean chlamydospore formation inside the plant roots resulting in a collection of 51 axenically cultured isolates of the elusive genus Piriformospora (recently transferred to the genus Serendipita). Based on morphological data, ISSR fingerprinting profiles and marker gene sequences, we propose that these isolates together with Piriformospora williamsii constitute a species complex designated Piriformospora (= Serendipita) 'williamsii.' A selection of isolates strongly promoted plant growth of in vitro inoculated Arabidopsis seedlings, which was evidenced by an increase in shoot fresh weight and a strong stimulation of lateral root formation. This isolate collection provides unprecedented opportunities for fundamental as well as translational research on the Serendipitaceae, a family of fungal endophytes in full expansion

Voriconazole, a safe alternative for treating infections caused by the Chrysosporium anamorph of Nannizziopsis vriesii in bearded dragons (Pogona vitticeps)

Dermal and systemic infections caused by the Chrysosporium anamorph of Nannizziopsis vriesii (CANV) are highly prevalent in reptiles and may result in severe disease and high mortality. Due to the high incidence of therapeutic failures, optimizing treatment is required. We first determined in this study the minimal inhibitory concentrations (MIC) of itraconazole, voriconazole, amphotericin B and terbinafine against 32 CANV isolates. For voriconazole, amphotericin B and terbinafine a monomodal MIC distribution was seen, whereas a bimodal MIC distribution was present for itraconazole, indicating acquired resistance in one isolate. Fourteen naturally-infected bearded dragons (Pogona vitticeps), from the same owner, were treated orally with either itraconazole (5 mg/kg q24h) or voriconazole (10 mg/kg q24h). The clinical condition, drug plasma concentrations and the presence of CANV in skin samples were followed. The animals were treated until complete clearance of the fungus. The plasma concentrations of voriconazole and itraconazole exceeded the minimal inhibitory concentrations of the CANV isolates. Elimination of CANV was achieved on average after 27 and 47 days of treatment with itraconazole and voriconazole, respectively. Whereas only 2 out of 7 survived after itraconazole treatment, only a single animal died in the voriconazole treated group. In conclusion, based on a limited number of animals, voriconazole applied at a regimen of 10 mg/kg bodyweight (BW) q24h seems to be a safe and effective antimycotic drug to eliminate CANV infections in bearded dragons

Influence of Mycotoxins and a Mycotoxin Adsorbing Agent on the Oral Bioavailability of Commonly Used Antibiotics in Pigs

It is recognized that mycotoxins can cause a variety of adverse health effects in animals, including altered gastrointestinal barrier function. It is the aim of the present study to determine whether mycotoxin-contaminated diets can alter the oral bioavailability of the antibiotics doxycycline and paromomycin in pigs, and whether a mycotoxin adsorbing agent included into diets interacts with those antibiotics. Experiments were conducted with pigs utilizing diets that contained blank feed, mycotoxin-contaminated feed (T-2 toxin or deoxynivalenol), mycotoxin-contaminated feed supplemented with a glucomannan mycotoxin binder, or blank feed supplemented with mycotoxin binder. Diets with T-2 toxin and binder or deoxynivalenol and binder induced increased plasma concentrations of doxycycline administered as single bolus in pigs compared to diets containing blank feed. These results suggest that complex interactions may occur between mycotoxins, mycotoxin binders, and antibiotics which could alter antibiotic bioavailability. This could have consequences for animal toxicity, withdrawal time for oral antibiotics, or public health

Organic matter cycling along geochemical, geomorphic and disturbance gradients in forests and cropland of the African Tropics – Project TropSOC Database Version 1.0

The African Tropics are hotspots of modern-day land-use change and are, at the same time, of great relevance for the cycling of carbon (C) and nutrients between plants, soils and the atmosphere. However, the consequences of land conversion on biogeochemical cycles are still largely unknown as they are not studied in a landscape context that defines the geomorphic, geochemically and pedological framework in which biological processes take place. Thus, the response of tropical soils to disturbance by erosion and land conversion is one of the great uncertainties in assessing the carrying capacity of tropical landscapes to grow food for future generations and in predicting greenhouse gas fluxes (GHG) from soils to the atmosphere and, hence, future earth system dynamics. Here, we describe version 1.0 of an open access database created as part of the project &ldquo;Tropical soil organic carbon dynamics along erosional disturbance gradients in relation to variability in soil geochemistry and land use&rdquo; (TropSOC). TropSOC v1.0 contains spatial and temporal explicit data on soil, vegetation, environmental properties and land management collected from 136 pristine tropical forest and cropland plots between 2017 and 2020 as part of several monitoring and sampling campaigns in the Eastern Congo Basin and the East African Rift Valley System. The results of several laboratory experiments focusing on soil microbial activity, C cycling and C stabilization in soils complement the dataset to deliver one of the first landscape scale datasets to study the linkages and feedbacks between geology, geomorphology and pedogenesis as controls on biogeochemical cycles in a variety of natural and managed systems in the African Tropics. The hierarchical and interdisciplinary structure of the TropSOC database allows for linking a wide range of parameters and observations on soil and vegetation dynamics along with other supporting information that may also be measured at one or more levels of the hierarchy. TropSOC&rsquo;s data marks a significant contribution to improve our understanding of the fate of biogeochemical cycles in dynamic and diverse tropical African (agro-)ecosystems. TropSOC v1.0 can be accessed through the supplementary material provided as part of this manuscript or as a separate download via the websites of the Congo Biogeochemistry observatory and the GFZ data repository where version updates to the database will be provided as the project develops.</p