Vocal communication allows animals to express distress, territoriality, and most important, to attract mates. In the African Clawed frog, Xenopus laevis, vocal communication is unique, because not only do males advertise for mates using elaborate click vocalizations, but also females are able to advertise their reproductive readiness by eliciting a "rapping" call. Sex differences in vocal repertoire match sex differences in vocal circuitry. During development, the vocal circuitry in the male grows increasingly sensitive to circulating androgens. Androgens induce tremendous growth in the cartilage and musculature of the peripheral vocal organ, the larynx. Net addition of synapses and motor fibers soon follow providing communication from the motor nucleus in the hindbrain to the vocal organ. The laryngeal motor nucleus, n. IX-X, accumulates androgens that serve to protect n. IX-X neurons from programmed apoptosis. Females, who have low levels of circulating androgens, experience a profound net loss on n. IX-X neurons during this developmental critical period. Once the frogs reach sexual maturity males possess larger and more numerous n. IX-X neurons than females, as well as sizable sex differences in laryngeal robustness and physiology. These measurable sex differences yield vastly different vocal programs. Androgens continue to maintain a critical role in governing breeding season trophic effects and mediating call production. Because male X. laevis are so susceptible to the effects of androgens, they may also be sensitive to the actions of endocrine disrupting chemical agents. The vocal system of X. laevis and its androgen sensitivity thus provide an ideal model for studying changes imposed to the anatomy and physiology of the system by the brominated flame retardant, PBDE-209, a putative anti-androgen and common pollutant. The present studies investigate how PBDE-209 affects the male vocal system when animals are exposed during the androgen-sensitive critical period of vocal system development and during adulthood when the tissues are utilizing androgens to vocalize. PBDE-209 effectively reduces male n. IX-X number and size at higher concentrations after exposure during the organizational critical period. Similar dose-dependent effects were observed in adult n. IX-X neurons. Moreover, PBDE-209 inhibited male-typical vocalization by reducing the number of calls elicited as well as the average call amplitude. These data strongly suggest that PBDE-209 has cytotoxic effects that alter n. IX-X anatomy and function, and may be mediated through pathways that include blocking the androgens necessary for proper vocal system development.

In the work underlying this thesis solid-phase microextraction (SPME) was evaluated as a passive sampling technique for organophosphate triesters in indoor air. These compounds are used on a large scale as flame-retarding and plastizicing additives in a variety of materials and products, and have proven to be common pollutants in indoor air. The main objective of this work was to develop an accurate method for measuring the volatile fraction. Such a method can be used in combination with active sampling to obtain information regarding the vapour/particulate distribution in different indoor environments. SPME was investigated under both equilibrium and non-equilibrium conditions and parameters associated with these different conditions were estimated. In <b>Paper I</b>, time-weighted average (TWA) SPME under dynamic conditions was investigated in order to obtain a fast air sampling method for organophosphate triesters. Among the investigated SPME coatings, the absorptive PDMS polymer had the highest affinity for the organophosphate triesters and was consequently used in all further work. Since the sampling rate is dependent on the agitation conditions, the linear airflow rates had to be carefully considered. Sampling periods as short as 1 hour were shown to be sufficient for measurements in the ng-μg m-3 range when using a PDMS 100-μm fibre and a linear flow rate above 7 cm s-1 over the fibre. SPME under equilibrium conditions is rather time-consuming, even under dynamic conditions, for slowly partitioning compounds such as organophosphate triesters. Nevertheless, this method has some significant advantages. For instance, the limit of detection is much lower compared to 1 h TWA sampling. Furthermore, the sampling time can be ignored as long as equilibrium has been attained. In <b>Paper II</b>, SPME under equilibrium conditions was investigated and evaluated for organophosphate triester vapours. Since temperature and humidity are closely associated with the distribution constant a simple study of the effect of these parameters was performed. The obtained distribution constants were used to determine the air levels in a common indoor environment. SPME and parallel active sampling on filters yielded similar results, indicating that the detected compounds were almost entirely associated with the vapour phase To apply dynamic SPME method in the field a sampler device, which enables controlled linear airflow rates to be applied, was constructed and evaluated (<b>Paper III</b>). This device was developed for application of SPME and active sampling in parallel. A GC/PICI-MS/MS method was developed and used in combination with active sampling of organophosphate triesters in indoor air (<b>Paper IV</b>). The combination of MS/MS and the soft ionization achieved with methanol as reagent gas yielded high selectivity and detection limits comparable to those provided by GC with nitrogen-phosphorus detection (NPD). The method limit of detection, when sampling 1.5 m3 of air, was in the range 0.1-1.4 ng m-3. In <b>Paper V</b>, the developed MS method was used in combination with SPME for indoor air measurements. The levels detected in the investigated indoor environments range from a few ng to μg m-3. Tris(2-chloropropyl) phosphate was detected at a concentration as high as 7 μg m-3 in a newly rebuilt lecture room.

A key part of the development of new polymeric materials focuses on the use of flame-retardant additives, which help to reduce the inherent flammability of polymers and the production of smoke and toxic gases. The aim of this thesis was the preparation, characterization and application of new polymeric flame-retardant additives, which can lead to intumescent systems when mixed with ¨commodity¨ polymers. The synthesis of this kind of additives was carried out by chemical modification of different polymeric structures (alcohols, polyketones, polyaziridines) with phosphorous moieties, previously described as promoting flame retardance structures, and/or nitrogen containing moieties. The efficacy of some of these additives was tested by blending with polypropylene, one of the most commonly used thermoplastic. Flame retardancy behaviour of the blends, as well their compatibility and mechanical properties were studied, in order to observe how the flame retardant additives may affect the substrate properties. / Una parte fundamental del desarrollo de nuevos materiales poliméricos se centra en la utilización de agentes retardantes a la llama, los cuales contribuyen a reducir la inherente combustibilidad de los polímeros y la producción de humos y de gases tóxicos. El objetivo del presente trabajo ha sido la preparación, characterización y aplicación de nuevos aditivos retardantes a la llama de tipo polimérico que pueden dar lugar al mezclarse con polímeros termoplásticos de gran consumo a sistemas de tipo intumescente. La síntesis de estos additivos se ha llevado a cabo por modificación química de diferentes estructuras polimericas (alcoholes, policetonas, poliaziridinas) con compuestos fosforados, descritos previamente como promotores de retardancia a la llama y/o compuestos con nitrogeno. La eficacidad de algunos de estos additivos ha sido estudiada por mezclarse con polipropileno, uno de los más utilizados termoplasticos.

The goal of this study was to quantify the ambient air concentrations of polybrominated diphenyl ethers (PBDEs) from three locations within the Howard Curren Wastewater Treatment Facility located in Tampa, Florida. PBDEs have been linked to endocrine disruption, cancer, developmental concerns in children, as well as other toxic effects; however their precise roles concerning these deleterious effects remains to be determined. The present study was motivated by these potential health concerns posed by inhalational exposure to PBDEs. Ambient air was monitored with a Tisch Environmental PUF high volume sampler for 48 hours with collection on three types of media-quarts filter, PUF (polyurethane foam) and XAD-2 resin. The samples were then analyzed with GC/MS (gas chromatography/mass spectrometry) for eight PBDEs that are routinely detected. The results showed elevated levels of PBDEs at the 2nd and 3rd sampling locations indicating a possible increased presence in the ambient air at the facility. Levels of PBDE 47 ranked highest amongst the detected congeners. PBDE 209 was not detected at any site. The present results indicate that PBDEs may lead to an inhalational exposure, thus future experimentation is needed to fully evaluate the health complications associated with inhalational exposure route to PBDEs.

The objectives of the research are to establish the process of obtaining regenerated fibers and films from wood pulp and bagasse pulp with the ionic liquid 1-Butyl-3-methylimidazolium Chloride (BMIMCl) as a solvent; to study the impacts on tensile strength of different spinning parameters; to find the optimal spinning condition, and to obtain regenerated cellulose products with flame retardant properties. Solutions were obtained by dissolving cellulose (wood/bagasse) pulp into the BMIMCl. The solutions were extruded in a dry-jet and wet-spinning method using water as a coagulation bath. The obtained fibers were tested to evaluate the properties such as tensile strength, thermal property, thermal mechanical property, crystal order, and ionic liquid residue in obtained fiber. The orthogonal experiments were designed to find out the strongest affective variable and the optimal condition of the spinning process. The regenerated cellulose films with melamine resin or zinc oxide were obtained. Their flame retardant properties were tested. Cellulose fiber with melamine resin was also obtained. Thermo-gravimetric analyzer (TGA) was used to measure the thermal properties of obtained products, and to calculate their activation energies. Dynamic mechanical analysis (DMA) was used to determine the thermal mechanical properties of obtained fibers. Wide angle X-ray diffraction (WAXD) was used to measure the degree of crystallinity and degree of crystal orientation. The tensile strength was tested by a tensile machine. To evaluate the quantity of ionic liquid residue in the regenerated fibers, the instrumental methods of FT-IR and Mass Spectrometry were applied. Research results indicated increases in the degree of crystallinity and storage modulus under a higher fiber drawing speed. Both regenerated bagasse fibers and regenerated wood fibers had similar thermal properties. However, the regenerated bagasse fibers showed a higher degree of crystallinity and a higher tenacity than the regenerated wood fibers obtained under the same condition. The study also revealed water treatment would be helpful for eliminating the ionic residue in regenerated fibers. It was also found the concentration of cellulose in the BMIMCl solution affected the tensile strength of regenerated fiber mostly. Certain amount of melamine or zinc oxide nanoparticles contained in the cellulose matrix could improve the flame retardant property effectively. / text

Polyamide 6 (PA6) was melt-blended with an intumescent flame retardant (FR) and nanoparticles (multi-wall carbon nanotubes [MWNTs] and nanoclays) to produce multi-component FR-PA6 nanocomposites. Thermal, flammability properties, char residue morphology, and mechanical properties of FR-PA6 nanocomposites were characterized. The flame retardant properties were enhanced according to UL 94 and microscale combustion calorimeter (MCC) measurements, whereas the thermal stability was decreased. Mechanical properties of the bulk material, especially elongation at break, were severely reduced, with the exception of tensile modulus which increased significantly. FR-PA6 nanofibers were processed via electrospinning. Electrospinnability, morphology of the nanofibers, combustion, and thermal properties were also analyzed. As for the bulk-form nanocomposite, improved combustion properties of these nanofibers were successfully achieved though thermal stability was compromised. With proper FR additive, the synergism between MWNTs and nanoclays was observed in PA6 resin. / text

<p>Polybrominated diphenyl ethers (PBDEs) are a class of flame retardant chemicals that were added to furniture foam, electronics, plastics, and some textiles to reduce their flammability. While PBDEs have been phased out from use in current products, huge reservoirs of products containing PBDEs still exist. It is likely exposure to PBDEs will continue as older products are discarded and recycled. PBDEs are ubiquitous contaminants in indoor and outdoor environments due to their widespread use in many products and their ability to migrate out of treated materials.</p><p> Major health effect concerns from PBDE exposure identified in laboratory studies include neurotoxicity, reproductive/developmental toxicity, and thyroid disruption. Importantly, mammals metabolize PBDEs into the hydroxylated polybrominated diphenyl ethers (OH-BDEs), which are structurally similar to endogenous thyroid hormones. Thyroid hormones are essential for metabolic processes, growth, and development, particularly brain development. Multiple studies have demonstrated enhanced potency of OH-BDEs relative to the parent PBDE chemicals, particularly for neurodevelopmental processes. Additionally, in fish species, thyroid hormones are essential for transitioning between larval, juvenile, and adult life stages. Therefore, studying the effects of both PBDEs and OH-BDEs during sensitive developmental life stages (i.e. larval and juvenile development) is warranted. The hypothesis of this thesis research is that PBDE metabolites interfere with thyroid hormone signaling (through interacting with thyroid receptor and deiodinase enzymes) which may result in decreased growth, morphological deficits, and altered neurodevelopment. The objectives of this research project were to evaluate the toxicity of PBDE metabolites and mixtures of PBDEs/OH-BDEs on larval and juvenile zebrafish development, examining both potential modes of action as well as functional consequences of exposure in developing animals. </p><p>In the first aim of this thesis research, structural relationships were examined between eleven different halogenated phenolic compounds (OH-BDEs, OH-PCBs, halogenated phenols, and TBBPA) to test developmental toxicity in zebrafish from 0-6 days post fertilization (dpf). In addition, follow up studies were performed with the most toxic compound, 6-hydroxy- 2,2’,4,4’-tetrabromodiphenyl ether (6-OH-BDE-47), to examine effects on TH-mediated morphological development and to better understand its mechanism of action in zebrafish. Thyroid disrupting agents including propylthiouracil, iopanoic acid, and native thyroid hormones were also used as positive controls for morphologic studies. Exposures to 6-OH-BDE-47 (10 nM to 100 nM) during development resulted in severe delays, similar to exposures from the T3 and thyroid disrupting agents. Lower jaw deformities and craniofacial cartilage malformations were also observed following exposure to 6-OH-BDE-47 at doses greater than 50 nM. Of interest, these developmental delays were rescued by overexpression of TRβ mRNA during the exposure period. These data indicate that OH-BDEs can adversely affect early life development of zebrafish and suggest they may be impacting thyroid hormone regulation in vivo through downregulation of the thyroid hormone receptor. </p><p>In the second aim of this dissertation research, neurobehavioral performance was monitored in larval and juvenile fish following a developmental exposure to 6-OH-BDE-47. 6-OH-BDE-47 has been identified as a neurotoxicant in previous cell based assays, and was identified as overtly toxic to zebrafish larvae in Aim 1 of this research. Developmental exposures (0-6 dpf) to 6-OH-BDE-47 resulted in decreased larval swimming activity at 6 dpf, with persisting impacts on behavior at 45 dpf. Young adult fish, when tested at 45 dpf, exhibited increased fear/anxiety response in the novel tank diving task and hyperactivity in a test of sensorimotor habituation. These data indicate that exposures to PBDE flame retardants and their metabolites during critical developmental windows can alter long term cognitive responses more than a month after the exposure has ceased.</p><p>Finally, for the third aim of this dissertation research, zebrafish undergoing larval-juvenile metamorphosis were exposed to a mixture of PBDEs (30-600 µg/L DE-71) and OH-BDEs (1-300 nM) from 9-23 dpf. Metamorphosis is a unique developmental period in fishes which is partially mediated by thyroid hormones. Juvenile animals, like larval animals, represent a sensitive and unique subpopulation of animals. At the end of the exposure period (23 dpf), a subset of fish were reared in clean water until 45 dpf for neurobehavioral testing. Fish samples were collected at 3 time points throughout the experiments, Days 12, 23, and 45. Tissue accumulation of test chemicals was monitored, and juvenile fish treated with the High Mixture were found to accumulate over 100 µg/g ww ∑PentaBDEs. The highest mixture treatment was found to be acutely toxic to zebrafish juveniles, resulting in >85% mortality within 14 days of exposure. Fish treated with 30 nM 6-OH-BDE-47 or the lower mixture exhibited reduced morphology scores relating to fin, pigmentation, and swim bladder maturation. In addition, reduced skeletal ossification and caudal area was observed at earlier time points with treatment to 6-OH-BDE-47. These alterations were accompanied by increases in chondrogenic gene expression, declines in osteogenic gene expression, and increases in thyroid receptor expression. Approximately 3.5 weeks after the exposure period, juvenile fish were tested on neurobehavioral tasks of novel tank exploration and sensorimotor habituation, however, no significant treatment related effects on task performance were observed. Collectively, these data suggested that the larval/juvenile development stage is a sensitive developmental window which can be adversely impacted by PBDE/OH-BDE exposure.</p> / Dissertation

Tris(1-chloro-2-propyl) phosphate (TCPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCPP) are added to polyurethane foams in a variety of industrial and consumer products to prevent flame ignition. The gradual release of these flame retardants (FRs) from such products leads to contamination of various abiotic and biotic media, including wild birds. Recent studies demonstrated endocrine-disrupting effects of TCPP and TDCPP, including alteration of circulating thyroid hormone (TH) levels. The TH-pathway is essential for normal growth and development in birds. There are limited data on the toxicological effects of TCPP and TDCPP in avian species and, prior to this work, no study has examined their effects in avian embryos. This M.Sc. thesis investigates the developmental, molecular and biochemical effects of TCPP and TDCPP in chicken (Gallus gallus domesticus) embryos via egg injection studies. TCPP delayed pipping at doses ≥9.24 μg/g, both TCPP and TDCPP reduced embryo growth at the highest dose (51.6 μg TCPP/g and 45 μg TDCPP/g), and TDCPP decreased free plasma thyroxine and gallbladder size at 7.64 μg/g and 45 μg/g, respectively. Real-time reverse transcription polymerase chain reaction was used to measure changes in mRNA levels of hepatic genes that were responsive to these FRs in a previous in vitro study. TCPP dysregulated the expression of TH-responsive genes and xenobiotic metabolizing enzymes (cytochrome P450s; CYPs), whereas TDCPP only affected CYPs. Less than 1% of the administered TCPP or TDCPP was detected in egg contents following 19 days of incubation, indicating extensive metabolism of the parent compounds. DNA microarrays were used to perform a global transcriptional analysis on liver samples from embryos that exhibited adverse effects following TDCPP injection. 47 differentially expressed genes were identified at the 45 μg/g dose. Functional analysis revealed that immune function and lipid and steroid metabolism were major targets of TDCPP toxicity and indicated a state of cholestatic liver/biliary fibrosis. Since the TH-pathway is a key regulator of metabolic homeostasis, its disruption early in development is a potential cause of the observed adverse effects. This thesis demonstrates, for the first time, developmental and endocrine-disrupting effects of TCPP and TDCPP in an avian species and attempts to link phenotypic changes to molecular-level disruptions in hopes to improve the understanding of their modes of action.

Idag finns det flera hundra flamskyddsmedel på marknaden där en del är hälso- och miljöfarliga. Fytinsyra är en naturlig produkt från växtriket som är miljövänlig och icke-toxisk. Fytinsyra består till stor del av fosfor vilket gör att potential finns för ett grönt flamskyddsmedel vilket ska undersökas. Lösningar på 3 och 10 mass% fytinsyra har gjorts där sedan kalciumkloridhexahydrat, natriumhydroxid eller ammoniak med ett molförhållandet på 5 eller 12 har tillsatts. Tygbitarna, av bomull och polyester, doppades i lösningarna och torkades i 6 dagar för att sedan analyseras med ett ugnstest, förbränningstest, TGA och DSC. Bästa kombinationen för bomull blev när natrium tillsattes med ett molförhållande på 12 till 1. Denna lösning gav bäst resultat i förbränningstesten samt ger mest massa kvar enligt TGA analysen. Lösningen är även basisk vilket är bra då sura lösningar bryter ner bomullstyget. För bedömning av bästa kombinationen för polyester ligger DSC och TGA analyserna till grund. I DSC är det svårt att avgöra vilken lösning som är optimalast då natriumlösningarna höjer temperaturen för smältpunkten mycket medan effekten minskar som behövs för att smältningen ska äga rum har halverats i förhållande till obehandlad polyester. Däremot har effektförbrukningen för smältningen ökat för kalciumlösningarna medan temperaturen endast höjts någon grad. Därmed är det svårt att säga den optimala lösningen för polyester. / Today there are several hundred flame retardants on the market where some are hazardous for the health and environment. Phytic acid is a natural product from the plant kingdom, which is environmentally friendly and non-toxic. Phytic acid consists largely of phosphorus, which means that there is potential for a green flame retardant which will be investigated in this report. Solutions of 3 and 10% by weight of phytic acid were made where calcium chloride hexahydrate, sodium hydroxide or ammonia having a molar ratio of 5 or 12 were added. The cotton and polyester fabric pieces were dipped in the solutions and dried for 6 days, then analyzed by use of an oven test, a combustion test, TGA and DSC tests. The best combination for cotton was when sodium was added at a molar ratio of 12 to 1. This solution yielded the best results in the combustion test, and left the most bulk in accordance with the TGA analysis. The solution is also basic, which is good as acidic solutions break down the cotton fabric. To assess the best combination for polyester, the DSC and TGA analyzes were used. In DSC it is difficult to determine which solution is optimal as the sodium solutions raises the temperature where melting occurs by a lot, but the power needed for melting is halved relative to untreated polyester. On the other hand, the calcium solutions have increased the power needed for melting, but the melting point was raised by only some degree. Thus it is difficult to say which the optimal solution for polyester is.

Ce travail de recherche consiste à proposer une fonctionnalisation des surfaces textiles par le procédé sol-gel à partir d’alcoxysilanes. L‘objectif est de conférer aux textiles des propriétés hydrofuges, ignifuges et fluorescentes. La première partie de notre étude traite dans un premier temps les paramètres de synthèse des sols et leur application sur différentes étoffes textiles. Ensuite, nous nous sommes intéressés à la synthèse des sols avec des alcoxydes de silicium permettant d’avoir des propriétés hydrofuges. Par la suite, les propriétés d’adsorption et de non mouillabilité des textiles traités ont été déterminées selon le standard AATCC- 22 et celles mécaniques selon la norme ISO 13934. Nous avons également étudié la stabilité thermique par des analyses ATG et les propriétés de non mouillabilité de ces textiles en fonction de leur photovieillissement accéléré. Dans un deuxième temps et dans l’optique de développer des textiles ignifuges, nous avons montré que l’immobilisation des LIs à la surface des textiles peut être réalisée par le procédé sol-gel. Pour ce faire nous avons tout d’abord synthétisé des liquides ioniques à partir d’un alcoxyde de silicium halogéné. Le sel obtenu est ensuite greffé sur des matrices textiles par le procédé sol- gel.Enfin, la dernière partie de l’étude consiste en la synthèse de fluorophores organiques par un procédé utilisant le couplage de type Heck. Leurs propriétés de photoluminescence ont été étudiées. Nous avons ainsi pu les greffer sur des surfaces pour développer des traceurs textiles fluorescents et des sondes pH fluorescentes. / This work consists to provide a functionalization of textile surfaces by the sol-gel process using alcoxysilanes. The final aim is to impart water repellent, flame retardant and fluorescent features to textile surfaces. Firstly, the effects of synthesis parameters such as the concentration of the alcoxysilanes and the impregnation time of the fabrics in the solution (sol) prepared have been thoroughly investigated. Then, we have prepared a silica modified sol which is expected to induce a water repellent feature to textile. To investigate the water repellency under practical conditions, the common “rain test” was used according to AATCC test method 22-2005 also mechanical properties of treated un untreated textile was studied according to ISO 13934. Furthermore, thermal properties of sol-gel modified textiles were investigated and their water repellency abilities were assessed and compared after photo ageing upon UV irradiations.Secondly, we have showed that the immobilization of ionic liquids onto the surface of textile fabrics can be achieved by the sol-gel process, which is of a growing interest due to its simplicity and flexibility. For this aim, two ionic liquids were synthesized using halogenated alkoxysilane, and then grafted onto the cotton fabrics by sol- gel process .The functionalized cotton fabrics exhibit good water repellency and flame stability. Finally, a fluorophores bearing phenolic hydroxyl and pyridinium end groups have been synthesized and grafted into cellulosic fiber by sol -gel process. This fluorophores have been firstly synthesized by double Heck couplings, and then we have studied their photo physical behavior as function of their concentration both in ethanol and in the textile. We have also grafted the fluorophores in cellulosic textile by sol gel method to have fluorescent and PH-sensitive properties.