Tesi sul tema "HBCD"

Brominated flame retardants (BFRs) has for many years been used in products to reduce their

flammability, mainly in electronic products, textiles and construction materials.

In 2003, Sweden imported 300 tons of brominated flame retardants.

Leakage of these compounds has polluted natural environments. Fishes has shown increased

contents of these substances, especially fat fish, since brominated flame retardants tends to

accumulate in fatty tissues.

They are also regarded as persistent and that gives them the ability to travel long distances.

What also is really scary is that increased levels of brominated flame retardants have been

detected in human breast milk.

The knowledge of the brominated flame retardants is limited and not so much research has been

done in this field. There are many reasons though, to keep the research going. Partly their

structural resemblance to well-known toxics as PCB, but also their ability to accumulate in

biological systems and enrich in food chains.

In which way they affect humans we really don’t know yet. Experiments on mice have been done

and behavioural disturbances were observed as well as a decrease in learning capacity.

The BRFs chosen for this study are hexabromocyclododecan (HBCD) and a polybrominated

diphenyl ether (PBDE) called pentabromodiphenylether (BDE 99).

About 25 % of the flame retardants produced in the world every year, consists of the brominated

ones. If we look at the PBDEs it’s mainly tetrabromodiphenylether (BDE 47),

pentabromodiphenylether (BDE 99), octabromodiphenylether (BDE 205) and

decabromodiphenylether (BDE 209) that are common flame retardants.

As from July 1st 2006, PBDE was forbidden in electric and electronic products (15).

January 1st 2007, a Swedish prohibition concerning the use of BDE-209 was established. BDE-

209 is not allowed on the Swedish market if the content of substance exceed 0,1 percent of weight

(23).

BDE-99 is classified as environmentally dangerous and a healthrisk. It´s not only toxic for

waterliving organisms but also for humans if exposed during a long time (19).

We shall develop a well functioning, reproducible and economic method to analyse HBCD and

PBDE in sediment. It includes extraction, cleanup and sample analyses with a ECD (electron

capture detector) equipped capillary gas chromatograph.

Several analyses of adequate diluted standards has been analysed in a GC-ECD to find suitable

temperature gradients. Then we produced spiked sediment samples with known amounts of

standards. To homogenize the spiked samples we used a mixer. As a first step in the extraction we

used acetone as a solvent. Then we used cyclohexane and NaCl (2%) to separate the nonpolar and

polar substances from each other. Cleanup with concentrated sulphuric acid was done and for

some samples we also used Florisil. To concentrate the extract it was evaporated with N2(g).The

extract was then analysed in a GC-ECD and then the results was compared with the standards.

The result of this project showed that our method of extraction is useful. We managed to extract

50 % HBCD, 30 % BDE-99 and 60 % BDE-99 (dried sediment).

The two additive brominated flame retardants, tetrabromoethylcyclohexane (TBECH) and hexabromocyclododecane (HBCD) are used to prevent fire to start and spread. They are simply mixed with material and are most likely to leach out in the environment, because of non-covalently binding to the material. TBECH can exist as four pairs of enantiomers, α-, β-, γ- and δ-TBECH. The technical HBCD can exist as three pairs of enantiomers, α-, β- and γ-HBCD and two meso forms δ- and ε-HBCD. None of these compounds are produced in Sweden, but they are imported to industries. TBECH has been found in Beluga blubber and can accumulate in zebrafish. HBCD has been found in water environments and can be toxic to and bioaccumulate in water-living animals.

In this study, a method was developed for separation and detection of α-, β-, γ- and δ-TBECH on HRGC/HRMS. All TBECH-isomers could be separated with the developed method. How much of the TBECH isomers that were recovered after applying existing extraction and clean-up procedures, normally applied for clean-up and extraction of PCBs and PCDD/Fs, was evaluated. Low recovered amounts (6.8-35.5 %) of TBECH-isomers added in known amounts to three different whale samples indicate severe evaporation losses and possibly photolytic degradation. None of the four enantiomers were detected in the three whale samples. For HBCD analysis, both the chromatography and MS/MS parameters were optimised for δ- and ε- HBCD yielding good chromatography and sensitivity. However, due to technical difficulties during the time-period of this project, no whale samples could be analysed for HBCD on UPLC/MS/MS. 

L’hexabromocyclododécane (HBCD) a été utilisé comme additif dans des polystyrènes (PS). En 2013, l’HBCD a été inclus à la Convention de Stockholm comme Polluant Organique Persistant. Les denrées alimentaires d’origine animale (DAOA) constituent la source principale d’exposition de la population générale à ce polluant. Le niveau moyen d’exposition du consommateur ne représente pas un risque majeur pour la sécurité sanitaire des aliments (EFSA, 2011). Malgré des concentrations moyennes généralement proches d’un ng g-1 lipides dans les DAOA, des concentrations maximales supérieures à 2000 ng g-1 lipides dans certains échantillons d’œuf ont été rapportées. Plusieurs sources potentielles d’exposition orale des volailles existent. Les poules pondeuses pourraient être exposées majoritairement à l’isomère α-HBCD. Au vu de l’absence d’informations dans la littérature sur le devenir de l’α-HBCD chez la poule pondeuse, une expérimentation in vivo a été réalisée et a permis d’estimer la plupart des paramètres cinétiques du devenir de l’α-HBCD ingéré chez la poule pondeuse. Un modèle pharmacocinétique basé sur la physiologie (PBPK) de transfert de l’α-HBCD chez la poule pondeuse a été développé, calibré par des données de la littérature, soumis à analyse de sensibilité et plusieurs paramètres ont été ajustés sur des résultats in vivo. Une validation du modèle a été testée. Ce modèle a permis de déterminer l’influence des caractéristiques physiologiques de la poule pondeuse sur le devenir de l’α-HBCD en cas d’exposition à la molécule. Parmi les caractéristiques d’intérêt, le poids vif (PV) est celle qui influence le plus la concentration d’α-HBCD dans les tissus et les œufs. Un PV bas et des performances de ponte réduites prédisposent à une concentration plus élevée dans ces matrices. La mue produit une augmentation de la charge corporelle de la molécule. Ce modèle peut être extrapolé à d’autres animaux et molécules lipophiles après modification de certains paramètres
Hexabromocyclododecane (HBCD) has been used as an additive in polystyrene (PS). In 2013, HBCD was included in the Stockholm Convention as a Persistent Organic Pollutant. The foodstuffs of animal origin are the main source of exposure of the general population to this pollutant. The mean exposure level of the consumers to HBCD doesn’t represent a major risk to the food safety (EFSA, 2011). In spite of mean concentrations generally close to 1 ng g-1 lipids in the foodstuffs of animal origin, maximal concentrations higher than 2000 ng g-1 lipids have been reported in some egg samples. There are several potential sources of oral exposure of the hens to this pollutant. The hens could be exposed mainly to the α-HBCD isomer. Since the bibliographic synthesis highlights the absence of information about the α-HBCD kinetics in the laying hen, an in vivo experience has been realized and has allowed the estimation of the majority of the α-HBCD kinetic parameters in the laying hen. A physiologically based pharmacokinetic (PBPK) model has been developed, calibrated by literature data, submit to a sensitivity analysis and some parameters have been adjusted on the basis of experimental data. A validation of the model has been attempted. This model has allowed to determine the influence of the main physiological characteristics of the laying hen exposed to the molecule on the α-HBCD accumulation in tissues and transfer to eggs. Among the physiological characteristics of concern, the body weight (BW) is the main feature influencing the α-HBCD kinetics. If the hen is exposed to the α-HBCD, a low BW and low laying performances predispose the hen to have higher concentrations of the molecule in all the matrices. The molting stage raises the body charge of the molecule. This model can be extrapolated to other animals and lipophilic molecules after modification of some parameters

Das Ziel dieser Arbeit war die Untersuchung des enantiomerenspezifischen Umweltverhaltens des Flammschutzmittels Hexabromcyclododecan (HBCD). Zu Beginn erfolgte daher die Optimierung und Validierung eines enantiomerenspezifischen Analysenverfahrens für die Bestimmung von HBCD in Biota. Die errechneten mittleren Wiederfindungen lagen im Bereich von 100-102 % und die Nachweisgrenzen zwischen 0,131 und 0,255 pg g-1. Untersuchungen zur ubiquitären Verteilung von HBCD erfolgten an Eiern der Silbermöwe deutscher Nord- und Ostseeinseln (Probenahme 1988-2008). In allen Fällen dominierte alpha-HBCD das Diastereomerenmuster, wobei eine bevorzugte Anreicherung von (-)-alpha-HBCD sowie ein zeitlicher Trend aller Enantiomeren-Gehalte festgestellt wurde. Zur Klärung der Frage einer Bioakkumulation sowie -isomerisierung der HBCD-Stereoisomere erfolgten Langzeit-Fütterungsversuche an Spiegelkarpfen. Die Untersuchungen ergaben eine signifikante Akkumulation des jeweils gefütterten HBCD-Enantiomers, jedoch konnte die Hypothese der Bioisomerisierung nicht bestätigt werden. Ein weiterer Schwerpunkt lag in Untersuchungen zur cytochromabhängigen enantiomerenspezifischen Biotransformation von HBCD im Rahmen des Metabolismus an Lebermikrosomen diverser Spezies. Hier konnte gezeigt werden, dass HBCD dem Phase I-Metabolismus unterliegt und hydroxyliert wird. Dabei weist jedes HBCD-Enantiomer ein spezifisches Metabolitenmuster auf, was eine Zuordnung der hydroxylierten Verbindungen zum entsprechenden HBCD-Enantiomer erlaubt. Anhand von Zeitreihen sowie der Berechnung von Halbwertszeiten konnte der Verdacht eines enantiomerenspezifischen Metabolismus in Richtung einer Anreicherung von (-)-alpha- und (+)-gamma-HBCD bestätigt werden. Inkubationsansätze mit reinen Cytochrom (CYP)-Isoformen sowie molekülmechanische Berechnungen legen die Vermutung nahe, dass dem CYP3A4 eine Schlüsselrolle bei der Metabolisierung von HBCD zukommt.
The main emphasis of this thesis was on the enantio-specific environmental behaviour of the polybrominated flame retardant hexabromocyclododecane (HBCD). Initially, an enantio-specific analytical method for the determination of HBCD in biota was optimised and validated. The calculated mean recoveries ranged from 100 to 102 % and the limits of detection are in the range of 0.131 to 0.255 pg g-1. First investigations of the ubiquitous environmental distribution of HBCD were performed using herring gull eggs from different islands in the North and Baltic Sea (sampling 1988 to 2008). In all cases alpha-HBCD was the predominant diastereomer. Significant deviations from the racemic mixture revealed a preferred enrichment of the first eluting (-)-alpha-HBCD. In addition, a temporal trend of HBCD levels was observed. To clarify the issue of accumulation as well as bioisomerisation of HBCD stereoisomers, a long-term feeding study with mirror carps was performed. The results showed an accumulation of each initially fed HBCD enantiomer, but hypothesis of a bioisomerisation could not be confirmed. Another important focus of this work was to study the cytochrome-dependent enantio-specific biotransformation of HBCD enantiomers in various species of liver microsomes. It was shown that HBCD is subject to phase I metabolism. In the course of this process, HBCD is metabolised to hydroxylated products, whereas each HBCD enantiomer results in a specific metabolite pattern allowing the allocation of the corresponding hydroxylated compounds. Investigation of time series as well as the calculation of half-lives, the hypothesis of an enantio-specific metabolism towards an enrichment of (-)-alpha- and (+)-gamma-HBCD could be confirmed. Incubation mixtures with pure cytochrome (CYP) isoforms, as well as molecular mechanic calculations suggest that CYP3A4 plays a key role in the biotransformation processes of HBCD.

Polybrominated diphenyl ether (PBDE-47) and hexabromocyclododecane (HBCD) are brominated flame retardants (BFRs) commonly used in a wide range of consumer products. They bioaccumulate and persist in the environment, and have been detected in humans and wildlife. Their ability to pass the blood-brain barrier (BBB) and to accumulate in the brain has raised concern about the potential of BFRs to cause neurotoxicity. Functional genomics was used to investigate the modes of action of PBDE-47 and HBCD in two neuronal cell models namely mouse neuroblastoma (N2A) and neuroblastoma x spinal cord (NSC-19). It was established that PBDE-47 and HBCD reduce cell viability, increase lactate dehydrogenase (LDH) leakage and cause apoptosis as indicated by increased caspase-3 activity at low micromolar concentrations (1 - 4μM). A pre-incubation with the omega-3 fatty acid, docosahexaenoic acid (DHA), mitigated the toxic effect of HBCD in the N2A cell line, with a significant decrease in the LDH leakage. Transcriptome profiling revealed that exposure to PBDE-47 and HBCD affects expression of genes with overlapping functionalities. Both toxicants regulated genes related to calcium homeostasis, endoplasmic reticulum stress and lipid metabolism. Genes involved in thyroid hormone signalling, neurodegenerative diseases and nervous system development were also preferentially regulated. The fatty acid DHA altered the expression of genes that were also regulated by PBDE-47 or HBCD, and HBCD modulated DHA-induced gene expression. It was also established that HBCD exposure affect cellular zinc homeostasis, increasing the level of intracellular weakly bound Zn2+. This effect was ameliorated by the antioxidant NAC, suggesting that the [Zn2+] increase could have been caused by oxidative stress with release of Zn2+ from zinc-binding proteins. This result indicates for the first time that zinc signalling is a potential target of POP toxicity. In conclusion, we established that PBDE-47 and HBCD have toxicity effects on cells of neuronal origin starting at a concentration of 1μM and that exposure to either of these BFRs causes regulation of genes related to many cellular functions, several of which have been observed as BFR phenotypes in animal studies. It was also shown that zinc is a POP toxicity target and that cellular effects of BFRs are modulated by DHA.

Hexabromocyclododecane (HBCD) is a brominated flame retardant commonly used in industrial and household products to reduce the spread of fire and the risk of death. Similar to polybrominated diphenyl ethers (PBDEs), HBCD is a ubiquitous and persistent environmental contaminant, highly lipophilic and bioaccumulative, and has been detected throughout various ecosystems and phyla, thus posing potential cause for concern for top consumer species, including birds of prey. Captive adult American kestrels (Falco sparverius) were exposed by diet to HBCD at an estimated daily concentration of 0.8 μg HBCD / μL safflower oil per cockerel (or 800 ng/ g ww / day / pair); their offspring, used in this study, were exposed in ovo only to environmentally relevant HBCD concentrations of 164.13 ± 18.26 ng/g ww or to background concentrations in the control eggs (0.4 ± 0.04 ng/g ww). The in ovo exposed HBCD group of male nestling kestrels showed a reduced corticosterone response. Moreover, in ovo HBCD concentrations were correlated with reduced flying activities of juvenile males during hunting behaviour trials and delayed response times of juvenile female kestrels during predator avoidance behaviour trials, suggesting an ongoing effect of HBCD on corticosterone levels. These findings show that embryonic exposure to environmentally relevant concentrations of technical mixture HBCD influences the corticosterone response, hunting success and avoidance of potential predators in captive American kestrels.
L'Hexabromocyclododécane (HBCD) est un ignifuge bromé couramment utilisé dans les produits industriels et ménagers pour réduire les risques d'incendies et de mortalité. À l'instar des éthers diphényliques polybromés (EDPB), le HBCD est un polluant omniprésent et persistant de l'environnement, fortement lipophile et bioaccumulable, décelé dans divers écosystèmes et phylums et donc potentiellement préoccupant pour les espèces du haut de la chaîne alimentaire, dont les oiseaux de proie. L'étude consiste à exposer par leur alimentation des crécerelles d'Amérique (Falco sparverius) adultes en captivité à une concentration quotidienne estimée de 0,8 mg HBCD / μL d'huile de carthame par coquelet (c.-à-d. 800 ng / g pf/ jour / paire); leur progéniture, utilisée dans cette étude, ont été exposés in ovo à des concentration écologiquement pertinentes de HBCD 164,13 ± 18,26 ng / g pf ou des concentrations de fond (0,4 ± 0,04 ng / g pf) dans le cas des œufs de contrôle . Chez les oisillons mâles du groupe exposé au HBCD in ovo, il y a réduction de la sécrétion de corticostérone. En outre, les concentrations de HBCD in ovo sont corrélées à une réduction des activités de vol chez les mâles juvéniles durant des essais de comportement de chasse et des temps de réaction accrus chez les femelles juvéniles durant des essais de comportement d'évitement de prédateurs, ce qui suggère un effet continu du HBCD sur les niveaux de corticostérone. Ces constatations démontrent que l'exposition embryonnaire à des concentrations écologiquement pertinentes de HBCD dans un mélange technique a une incidence sur le taux de sécrétion de corticostérone, le taux de réussite des activités de chasse et l'évitement de prédateurs potentiels chez la crécerelle d'Amérique.

Brominated flame retardants (BFRs) have been used in a variety of consumer products to enhance their fire safety. This has resulted in exposure of the environment, wildlife and humans causing risks of endocrine disruption. The use restrictions of many BFRs have resulted in the introduction of other brominated chemicals (emerging BFRs) on the market. Humans are exposed to BFRs primarily via diet and dust ingestion, but the importance of the different exposure pathways has scarcely been studied. Children in particular have not been studied well due to lack of biomonitoring data. In this thesis, a mother-toddler cohort (n=24) from Uppsala was studied for their exposure to tri-decabrominated diphenyl ethers (tri-decaBDEs), isomer-specific hexabromocyclododecanes (HBCDs) and emerging BFRs (EBFRs). A clean-up and fractionation method was developed for determination of the above-mentioned BFRs in the same sample without dividing the sample. Measures of external exposure from dietary intake and dust ingestion were estimated. These were compared to internal concentrations (serum, feces) to determine which exposure pathways were most important for explaining the different BFR concentrations and patterns found in mothers and toddlers. Taking all the results into account, the toddlers’ higher serum levels of tetra-pentaBDEs seem to be the result of previous breastfeeding and those of octa-decaBDEs from exposure to house dust. For mothers, diet was estimated to be the main exposure route of tri-hexaBDEs and HBCDs. Dust ingestion was estimated to be the main route for BDE-209 exposure in mothers. Significant correlations were found between the tetra-decaBDE concentrations in matched serum and feces samples indicating that feces could be used as a non-invasive sample matrix for biomonitoring of PBDEs in toddlers. EBFRs were detected in the feces of toddlers and in a few serum samples from both mothers and toddlers indicating that exposure to these replacement chemicals occurs.

 At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.

Perfluorooctane sulfonate (PFOS) is widely used in industrial products and is potentially dangerous to the aquatic environment due to not being broken down whether by chemical or biological means, having a half-life of more than 41 years and disrupting hormones. Hexabromocyclododecane (HBCD) is the third most used brominated flame retardant and is of environmental concern as it bioaccumulates and magnifies in the food chain and is highly toxic to aquatic organisms. The purpose of this study was to examine the effect of PFOS and HBCD on the embryos of rainbow trout (Onchorhynchus mykiss) by analyzing lipid profiles with UHPLC/Q-TOF-MS. The fish embryos were treated with various concentrations of PFOS and HBCD (0.058-58 μg/l and 0.014-14 μg/l respectively) with DMSO as carrier solvent and then extracted after homogenization with 0.9% NaCl-solution followed by addition of ISTD mixture, methanol, methyl tert-butyl ether (MTBE) and MQ-water. The raw data was processed with MZmine-2.32. 153 lipids were identified with the main lipids consisting of glycerophospholipids and triacylglycerols. A two-tailed t-test was used to study the impact of the chemical exposure on the embryos, where p-values below 0.05 were lipids considered as significant change. The HBCD exposure caused significant change in various triacylglycerols, whereas PFOS exposure caused significant change in triacylglycerols as well as in glycerophospholipids such as PC(O-38:5) and LPC(20:4). The results were in alignment with previous studies.

Humans are exposed to persistent organic pollutants (POPs) such as brominated flame retardants (BFRs, specifically polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD)) and perfluoroalkyl acids (PFAAs, specifically perfluoroalkane sulfonate (PFOS) and perfluorooctanoic acid (PFOA)). They are used in consumer products found in cars, offices, homes and day care centers. Diet was earlier thought to be a major human exposure route for legacy POPs, but does not account for body burdens found for many new POPs and indoor exposure from air and dust has been hypothesized as also important. In this thesis, BFRs in air and dust, and PFAAs in dust from different indoor microenvironments in Sweden were analysed, and the results used to estimate human exposure. BFRs and PFAAs were detected in dust from all microenvironments and PBDEs in all air samples. BFR and PFAA exposure occurs mostly in peoples’ homes with toddlers having higher intakes from dust ingestion than adults. Inhalation and dust ingestion play minor roles compared to diet for humans with median exposures, but in worst case scenarios, dust ingestion may be significant for a small part of the Swedish population. Sampling using home vacuum cleaner bag dust and researcher-collected above floor dust was compared. Correlations were seen for ∑OctaBDE and ∑DecaBDE but not for ∑PentaBDE and HBCD. Higher PBDE concentrations were found in above floor dust but higher HBCD concentrations were found in vacuum cleaner bag dust. BDE-47 concentrations were correlated between vacuum cleaner bag dust and breast milk, indicating exposure through dust ingestion. Similar concentrations of PBDEs were measured in indoor and outgoing air from day care centers, apartment and office buildings. Indoor air explained 54-92% of ∑PentaBDE and 24-86% of BDE-209 total emissions to outdoor air in Sweden, supporting the hypothesis that the indoor environment is polluting ambient air via ventilation systems.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Accepted. Paper 3: Accepted. Paper 4: Manuscript.

Many modern products, especially electronic goods, are protected by brominated flame retardants (BFR). Some of the most common flame retardants are polybrominated diphenylethers (PBDE), tetrabromobisphenol-A (TBBP-A) and hexabromocyclododecane (HBCD). These compounds have been found in environmental samples and shown to have physiological effects on experimental animals. This thesis considers end-of-life aspects of brominated flame retardants. When spread in the environment, these compounds may be degraded into other forms. For example, if sludge contaminated with PBDE is used as an agricultural fertilizer, the PBDE could be degraded by sunlight to species of PBDE with lower degree of bromination and, to some extent, also form polybrominated dibenzofurans (PBDF). In addition, PBDF and polybrominated dibenzo-p-dioxins (PBDD) are formed during combustion of brominated flame retardants. When waste products with brominated flame retardants are co-combusted with household waste or other chlorinated fuel, polybrominated- chlorinated dibenzo-p-dioxins (PBCDD) and polybrominated- chlorinated dibenzofurans (PBCDF)will be formed. The bromin/chlorine composition of dioxins and furans is dependent on the bromine/chlorine ratio in the fuel, but the types of brominated flame retardants that are being combusted is less important. In the studies reported here, bromine levels higher than "normal" for household waste has been used. The results show that there is a pronounced increase in total dioxin levels in fluegas when when bromine is present, implying that waste containing brominated flame retardants should only be incinerated at combustion plants with effecient air pollution control devices.

The dietary intake of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) have been estimated for Swedish children. A dietary survey performed in 2003, including 4, 8-9 and 11-12 year olds, and concentrations in individual food items were combined. The food included in the study was mainly of animal origin, consisting of fish and shellfish, dairy products, meat products, eggs, animal and vegetable fats and fats from miscellaneous food products. The medium-bound intake of PBDEs (9 congeners) were estimated to 23.0 ng/day, 30.9 ng/day and 27.7 ng/day for 4, 8-9 and 11-12 years olds respectively. The corresponding estimations for HBCD were 7.94 ng/day 10.7 ng/day and 9.46 ng/day for 4, 8-9 and 11-12 years olds respectively. These results show a higher daily intake for 8-9 year olds compared with the other age groups. However, when estimating the daily intake per kg bw, the intake decreases with age. BDE-47 contributed the most to the total intake of PBDEs, with approximately 40%. The food group contributing the most to the intake of PBDEs and HBCD was fish and shellfish, of which non-Baltic fatty fish was the largest contributor. There were no considerable differences between boys and girls in any of the aspects examined. The result from this study show a lower intake of PBDEs and HBCD in Swedish children compared with children in other studies made in Europe and the United States.

Bromerade flamskyddsmedel används för att skydda brännbara material från att fatta eld, till exempel skyddas textilier och plaster i bland annat elektronik, fordon och möbler. Två typer av bromerade flamskyddsmedel är polybromerade difenyletrar (PBDE) och hexabromocyklododekan (HBCD). Dessa är additiva flamskyddsmedel och blandas i materialet som ska skyddas men binder inte in i produkten och kan därför lätt läcka ut i miljön, vilket också har skett. Halter har påträffats i miljön och i biota långt från plaster där ämnena produceras eller används.

PBDE och HBCD har visats ha hormonstörande och neurotoxiska effekter i studier på råtta och mus. Thyroxinnivåerna sjunker vid exponering av PBDE och HBCD, vilket skulle kunna leda till sköldkörtelproblem och störd utveckling av bland annat hjärnan om exponering sker perinatalt. De neurotoxiska effekterna inkluderar inlärnings- och minnessvårigheter och ett förändrat beteende med hyper- och hypoaktivitet som följd.

Human exponering för PBDE och HBCD sker främst via födan och speciellt via animaliska produkter då dessa ämnen är lipofila, bioackumulerande och ofta biomagnifierande vilket gör att de påträffas i högre koncentrationer högre upp i trofinivåerna. Studier från bland annat Sverige och Finland visar att fisk och skaldjur är den största källan till intag av PBDE.

De flesta intagsberäkningar av PBDE och HBCD baseras på livsmedelskonsumtionen hos vuxna och visar följaktligen endast hur intaget ser ut för den delen av populationen. För barn, som är en av de känsligaste grupperna i populationen, finns inte många studier att tillgå, varken från Sverige eller andra delar av världen. I den här studien har därför intaget av PBDE (summan av 9 kongener) och HBCD beräknats för barn i Sverige.

I en rikstäckande kostundersökning utförd 2003 deltog barn i åldrarna 4, 8-9 och 11-12 år. De fick i en matdagbok ange sin konsumtion under fyra på varandra följande dagar. Data från denna undersökning kombinerades sedan med haltdata från olika livsmedel för att räkna ut intaget av PBDE och HBCD på individbasis. Undersökningen innefattade främst animaliska livsmedel och innehöll därför fisk och skaldjur, mejeriprodukter, köttprodukter, ägg, animaliskt och vegetabiliskt fett och fett från övriga livsmedel.

Resultaten visar att födointaget av PBDE var 23,0 ng/dag, 30,9 ng/dag och 27,7 ng/dag för 4, 8-9 respektive 11-12 åringar. Intaget av HBCD beräknades till 7,94 ng/dag, 10,7 ng/dag och 9,46 ng/dag för 4, 8-9 respektive 11-12 åringar. Detta visar att 8-9 åringar har det högsta dagliga intaget av PBDE och HBCD. När intaget beräknas på kroppsvikt däremot, har de yngsta barnen det högsta intaget som sedan sjunker med åldern. Fisk och skaldjur var den största källan till intaget av PBDE och HBCD, trots att konsumtionen av dessa livsmedel var relativt lågt. Det fanns ingen större skillnad mellan pojkar och flickor, varken i intag av PBDE eller av HBCD. Jämfört med de få studier som gjorts i andra länder, är det tydligt att svenska barn har ett lägre intag av PBDE och HBCD.

Undersökningen tyder också på att intaget av PBDE och HBCD hos svenska barn, utifrån de kunskaper vi har idag, inte utgör någon risk med avseende på de effekter av PBDE och HBCD som påträffats i toxikologiska studier. Däremot är barn i ett känsligt skede i livet och upprepad exponering samt exponering för flera miljögifter samtidigt skulle kunna påverka deras utveckling negativt.

Ziel dieser Arbeit war es, ein enantiomerenspezifisches Analysenverfahren für die Bestimmung von Hexabromcyclododecan (HBCD) in Biota-Proben zu entwickeln und die bei erhöhten Temperaturen auftretende Isomerisierung der HBCD-Stereoisomere zu untersuchen. Als erstes wurden die sechs HBCD-Enantiomere isoliert, mittels Einkristallstrukturanalyse, NMR- und IR-Spektroskopie charakterisiert und erstmals die spezifischen Drehwinkel der reinen Enantiomere mit den absoluten Konfigurationen und der Elutionsreihenfolge auf einer chiralen beta-PM-Cyclodextrin-Phase korreliert. Die Untersuchungen der HBCD-Enantiomere in Biota-Proben wurden mit einem HPLC-Tandem-MS-System unter Verwendung einer Kombination aus einer C18- und einer chiralen beta-PM-Cyclodextrin-Phase durchgeführt. Das entwickelte Analysenverfahren wurde validiert und ein Messunsicherheitsbudget erstellt. Die mittlere Wiederfindung für die internen Standards lag im Bereich von 96 - 104 % und die Nachweisgrenzen lagen zwischen 6 und 21 pg/g. Mit Hilfe dieses Analysenverfahrens wurden sowohl maritime als auch Süßwasser Biota-Proben von verschiedenen Probenahmepunkten in Europa untersucht. Die ermittelten Enantiomeren-Verhältnisse, die in allen Fällen vom (±)-alpha-HBCD dominiert wurden, zeigten signifikante Abweichungen von den razemischen Zusammensetzungen. Auffällig hierbei war, dass eine bevorzugte Anreicherung der zuerst eluierenden HBCD-Enantiomere ((-)-alpha-, (-)-beta- und (+)-gamma-HBCD) stattfand. Im Ergebnis der Untersuchungen zur thermisch induzierten intramolekularen Isomerisierung der HBCD-Stereoisomere konnten die verschiedenen Isomerisierungsreaktionen eindeutig aufgeklärt und die jeweiligen Geschwindigkeitskonstanten bei einer Temperatur von 160 °C ermittelt werden. Ergänzend wurde die Isomerisierung mit Hilfe der statistischen Thermodynamik unter Verwendung eines neuen Ansatzes für die klassische Hybrid Monte-Carlo-Simulation untersucht.
The major objectives of this thesis were the development of an analytical procedure for the enantio-specific determination of hexabromocyclododecane (HBCD) in biota samples and the investigation of the interconversion of the individual HBCD isomers at elevated temperatures. The six HBCD enantiomers were isolated, characterised by X-ray diffractometry, NMR- and IR-spectroscopy and the sense of rotation was correlated for the first time with the absolute configurations of the HBCD enantiomers as well as their order of elution on a chiral beta-PM-cyclodextrine-phase. Trace quantification of the individual HBCD enantiomers was achieved by means of high performance liquid chromatography coupled to tandem mass spectrometry equipped with a combination of a C18- and a chiral analytical column. Validation data and an uncertainty budget were determined. The mean recoveries of the different enantiomeric internal standards ranged from 96 to 104 % and the limits of detection are in the range of 6 to 21 pg/g. The analytical procedure was successfully applied to marine and freshwater biota samples from different European sites. The enantiomeric pattern of the six HBCD enantiomers, with (±)-alpha-HBCD as the dominant diastereomer, was determined for all biota samples and showed in most cases a significant deviation from the technical racemate. In these cases a preferential enrichment of the first eluted enantiomers ((-)-alpha-, (-)-beta- and (+)-gamma-HBCD) could be observed. The unambiguous elucidation of the individual isomerisation reactions as well as the quantification of all respective rate constants for the interconversion of the HBCD stereoisomers at 160 °C was done. A mechanistic explanation for the differences of the rate constants which govern the composition of HBCD diastereomers at equilibrium was given. Additionally, the interconversion was investigated by means of statistical thermodynamics using a new approach to classical hybrid Monte-Carlo simulations.

En la present tesi doctoral s’han estudiat diversos mètodes per a l’eliminació de contaminants orgànics persistents en olis de peix amb finalitat alimentària. S’han posat al punt les metodologies d’anàlisi necessàries per a la correcta determinació d’aquests compostos en la matriu d’estudi. S’han avaluat amb detall les etapes de purificació de la mostra, fraccionament dels analits i anàlisi instrumental. El mètode ha estat validat amb resultats satisfactoris, i s’ha comprovat el seu bon funcionament a través de la participació en diversos exercicis d’intercalibtage, així com la realització de diversos estudis amb mostres reals d’oli de peix. S’ha estudiat l’eliminació dels contaminants orgànics persistents a través d’adsorbents sòlids amb base silícica i carbonàcia. Les condicions experimentals han estat estudiades més a fons mitjançant dissenys d’experiències, per acabar optimitzant el mètode d’adsorció amb un disseny d’evolució. Els millors resultats s’han obtingut amb el carbó actiu, que mostra una elevada eficàcia en l’eliminació de PCDD/Fs, d-l PCBs i HCB. S’ha estudiat l’eliminació dels contaminants orgànics persistents mitjançant tècniques de degradació fotoquímiques. Inicialment s’ha fotodegradat cada família de contaminants per separat, per poder estudiar més a fons les condicions necessàries per la seva eliminació, així com els seus mecanismes i productes de degradació. Posteriorment s’ha estudiat la fotodegradació simultània dels analits d’interès en oli de peix. Aquesta tècnica s’ha mostrat efectiva en l’eliminació de DDT, PBDEs, HCB i PCBs similars a dioxines. Paral•lelament als estudis d’eliminació mitjançant adsorbents sòlids i tècniques fotoquímiques, s’ha comprovat la qualitat dels olis de peix abans i després del tractament. El procés d’adsorció en sòlids no afecta significativament a la qualitat de l’oli, mentre que les tècniques fotoquímiques degraden una part dels àcids grassos insaturats. S’ha estudiat l’eliminació de contaminants orgànics persistents en oli de peix mitjançant la combinació de les dues tècniques estudiades anteriorment, amb una primera etapa de degradació fotoquímica i una segona etapa d’adsorció. S’han comparat els resultats finals d’eliminació que s’obtenen amb cada un dels mètodes desenvolupats (adsorció, fotodegradació i combinat). L’adsorció en carbó actiu és el procés més adequat per l’eliminació de COPs en oli de peix. S’ha realitzat un estudi dels nivells diastereomèrics i enantiomèrics d’un contaminant emergent -l’hexabromociclododecà (HBCD)- en oli de peix. S’ha avaluat la seva eliminació de la matriu d’estudi mitjançant adsorbents amb base carbonàcia i degradació fotoquímica, sent principalment eliminat per aquesta segona via.
En la presente tesis doctoral se han estudiado diversos métodos para la eliminación de contaminantes orgánicos persistentes en aceites de pescado con finalidad alimentaria. Se han desarrollado los métodos de análisis necesarios para la correcta determinación de estos compuestos en la matriz de estudio. Se han evaluado con detalle las etapas de purificación de la muestra, fraccionamiento de los analitos y análisis instrumental. El método ha sido validado con resultados satisfactorios, y se ha comprobado su buen funcionamiento mediante ejercicios de intercalibraje, así como la realización de diversos estudios con muestras reales de aceite de pescado. Se ha estudiado la eliminación de los contaminantes persistentes mediante adsorbentes sólidos con base silícica y carbonacea. Las condiciones experimentales han estado estudiadas en profundidad mediante diseños de experiencias y de evolución. Los mejores resultados se han obtenido con carbón activo, que demuestra una elevada eficacia en la eliminación de PCDD/Fs, dl-PCBs y HCB. Se ha estudiado la eliminación de los contaminantes orgánicos persistentes mediante técnicas de degradación fotoquímica. Inicialmente se ha fotodegradado cada familia de contaminantes por separado, para poder estudiar más a fondo las condiciones necesarias para su eliminación. Posteriormente se ha estudiado la degradación simultánea de los analitos de interés en aceite de pescado. Esta técnica se ha mostrado efectiva en la eliminación de DDT, PBDEs, HCB y PCBs similares a dioxinas. Paralelamente a los estudios de eliminación mediante adsorbentes sólidos y técnicas fotoquímicas, se ha comprobado la calidad de los aceites de pescado antes y después del tratamiento. El proceso de adsorción en sólidos no afecta significativamente a la calidad del aceite, mientras que las técnicas fotoquímicas degradan una parte de los ácidos grasos insaturados. Se ha estudiado la eliminación de contaminantes orgánicos persistentes en aceites de pescado mediante la combinación de las dos técnicas estudiadas anteriormente, con una primera etapa de degradación fotoquímica y una segunda etapa de adsorción. Se han comparado los resultados finales de eliminación que se obtienen con cada uno de los métodos desarrollados. La adsorción en carbón activo es el proceso más adecuado para la eliminación de COPs en aceite de pescado. Se ha realizado un estudio de los niveles diastereoisoméricos y enantioméricos de un contaminante emergente –HBCD- en aceite de pescado. Se ha evaluado su capacidad de eliminación de la matriz de estudio mediante adsorbentes con base carbonacia y degradación fotoquímica, siendo principalmente eliminado por la segunda vía.
During the present doctoral thesis several methods for the elimination of persistent organic pollutants from fish oil have been studied. Analytical methodologies for the determination of these compounds in fish oil have been developed. Sample purification, fractionation of the analytes and instrumental determination steps have been deeply studied. The method has been validated with satisfactory results, and its performance has been verified through its participation in several intercalibration exercises and studies with real fish oil samples. Elimination of persistent organic pollutants with silicon and carbon-based adsorbents has been studied. The experimental conditions have been studied in depth with an experimental design, to finally optimize the adsorption method using an evolutionary design. Best results have been obtained with the active carbon, showing high efficiency of the removal of PCDD/Fs, dioxin-like PCBs and HCB. Elimination of persistent organic pollutants with photochemical degradation techniques has been studied. Initially, each family of pollutants has been photodegraded separately, to determine its degradation conditions, as well as degradation mechanisms and by-products. Later, simultaneous photodegradation of the analytes has been studied in fish oil. This technique has shown high efficiency on the degradation of DDT, PBDEs, HCB and dioxin-like PCBs. The quality of the oils before and after the treatments with solid adsorbents and photochemical degradation has also been studied. The adsorption process does not significantly affect the quality of the oils, while photochemical techniques can degrade the unsaturated fatty acids. Elimination of persistent organic pollutants in fish oil combining adsorption in solids and photochemical degradation has been studied. Results obtained with each of the developed methodologies (adsorption, photodegradation and combined method) were compared. Adsorption in active carbon is the most suitable process for COPs elimination in fish oil. Finally, diastereoisomeric and enantiomeric levels of an emerging pollutant –hexabromocyclododecane (HBCD)- in fish oil have been studied. Its elimination has been evaluated with carbon-based adsorbents and photochemical degradation, being mainly eliminated with the photodegradation techniques.

The global reduction in the use of PBDEs and HBCD as flame retardants has opened the way for the introduction of “Novel” BFRs (NBFRs) in place of the banned formulations, indicating those BFRs that are new in the market or newly/recently observed in the environment in respect to PBDEs and HBCD. Consequently, consumption and production of these NBFRs will keep rising, and increasing environmental levels of these chemicals are expected in the near future. Important representatives of this group are decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), and pentabromoethylbenzene (PBEB). In Italy, previous studies have shown that some BFRs (PBDEs) were measured at high concentrations in the Varese province due to the presence of a great number of textile and plastic industries, and particularly in the sediments of Lake Maggiore, where those facilities wastewaters are finally collected mainly through two lake tributaries (Bardello and Boesio). For these reasons, the present thesis has the aim to evaluate the presence, and the potential bioaccumulation and biomagnification processes of six different classes of BFRs (PBDEs, HBCD, DBDPE, BTBPE, HBB and PBEB) in the Lake Maggiore ecosystem, with particular regard to zebra mussels (Dreissena polymorpha), zooplankton, one littoral fish species (common roach - Rutilus rutilus), and two different pelagic species (twaite shad – Alosa agone and European whitefish – Coregonus lavaretus). Finally, the study has also considered the BFR contamination in the lake sediments with the aim of characterizing in detail the possible presence of temporal trends and/or identifying potential sources of contamination. Moreover, it is plausible that the BFR uptake by benthic organisms, followed by fish predation, might be a significant source of bioaccumulation.

Human β-defensins (hBDs) are a family of cationic peptides able to directly kill a wide range of microorganisms including bacteria, fungi and viruses. In addition to their antimicrobial activities, defensins also contribute to the modulation of both the host innate and adaptive immunity. In this project, we demonstrate that the αCD3/28 co-stimulation of human CD4+ T cells in the presence of 10μg/ml hBD-2 or hBD-3 together causes an up-regulation in numbers of CD4+CD69+CD25+ and CD4+CD69-CD25+ T cell subsets, indicating that the treatment of hBD-2 and 3 enhances CD4+ T cell activation. Consistent with this finding, proliferation assay using CFSE suggests that hBD-2 and hBD-3 treatment in vitro induces the proliferation of CD4+ T cells following by 96hrs culture. Analysis of expression of the regulatory T cells (Tregs) specific marker, FoxP3, reveals a shift in the CD4+CD127-CD25+ Treg subset at 18hrs. However, at the later time point, we found that the percentage of FoxP3+cells decreased in the CD4+CD127-CD25+ Treg population, whereas the presence of the FoxP3+CTLA-4+ Treg subset increased. These data indicate that Treg suppressive function may be potentially defective following the co-incubation of purified T cells with either hBD-2 or hBD-3 for 42hrs in vitro due to the apparent loss of FoxP3 expression. We further characterise the role of hBD-2 and hBD-3 in driving human CD4+ T cells polarisation. Our in vitro data suggests that treatment with hBD-2 and hBD-3 can not only induces effector T cell (Teff) differentiation into RORγt+T-bet+ (Th17/Th1) cells, but can also trigger the differentiation of Treg expressing RORγt and T-bet rather than the master controller of Treg function, FoxP3. This apparent plasticity of T cell phenotype allows them to convert from Treg to Th1/17-like effector T cell phenotype following 18hrs in culture. By 42hrs in culture, treatment with hBD-2 and hBD-3 induced both Teff cell and Treg cell differentiation towards the Th17-like phenotype. Compared with the treatment with hBD-2, treatment with hBD-3 induced a more pronounced effect to increase levels of RORγt in CD4+ T cells. This elevated expression may, in turn, be responsible for the induction of higher IL-17A secretion. Consistent with this idea, it was found that treatment with hBD-3 but not hBD-2 was capable of inducing the higher level of secretion of IL-17A. Additionally, treatment with hBD-3 induced an increased expression of IL-6, which is capable of driving the differentiation of naïve T cells towards IL-17-producing Th17 cells. Functionally, using the Treg suppression assay, the data suggested that hBD-2 may dampen down Treg cell ability to induce suppression of Teff cell activity. Interestingly, co-culture with hBD-2 would also appear to increase Teff cell resistance to Treg immunoregulation in vitro. Further investigation using microarray gene analysis revealed chemokine C-C motif ligand 1 (CCL1) as potential genes responding to hBD-2 treatment. The blockade of CCL1 has been reported to inhibit Treg suppressive function. Thus, this study explored the function of these antimicrobial candidates in regulating CD4+ T cell plasticity which could result in hBD-2 and hBD-3 being able to regulate its own production, but also may regulate Treg and Teff cell development and function, thus strengthening the link between innate and adaptive immunity.

This study seeks to examine the role of presidential leadership in internationalization on historically Black college and university (HBCU) campuses. HBCUs comprise a small but important segment of U.S. higher education, as they are responsible for 20% of African American graduates in the country. Unfortunately, many of these institutions have yet to address the urgent need to internationalize their campus in a systematic, relevant way. This research study was conducted on the campuses of three public HBCUs working to advance internationalization. This study explores answers to the following questions: (a) What is the role of the President in advancing or sustaining internationalization on an HBCU campus? (b) What is the relationship between the President and the Senior International Officer (SIO)? and (c) What leadership frames do the Presidents use to advance or sustain comprehensive internationalization? Site visits to each institution included interviews with the President, the Provost, the SIO, and faculty.

Results show that the Presidents recognized their responsibility to articulate why internationalization is important for the university and how it aligns with the mission of preparing students to navigate a globally connected world. Results indicate that the Presidents impact how internationalization gets implemented through direct and indirect interaction with the SIO and by sustaining a strong infrastructure, particularly in the form of a unit responsible for internationalization initiatives. The findings indicate that while the SIO does not report directly to the President, a more effective reporting line assigns the SIO a faculty rank with a reporting line to the Provost. Analysis of the data shows that each President utilized at least one dominant leadership frames identified by Bolman and Deal (2013), two of them also exhibited a secondary frame, and none applied a multi-frame approach. With longer time at the institution, these leaders may discover the need to incorporate different leadership frames to respond to rising challenges. This study affirms the importance of presidential leadership factors in the successful implementation of internationalization on these campuses.

This study examined, from a qualitative approach, the impact of vision, personal philosophies and ideologies on the institutional administration of selected HBCU presidents. The study was based on the premise that a president's vision directly influenced their ability to lead their institution as it related to the following areas: institutional administration, academic affairs, student affairs, personnel administration and financial management. The researcher found that vision had a direct and profound impact on the actions of the selected HBCU presidents and further found that each of the five areas of emphasis was guided by the presidents vision. The conclusions drawn from the findings suggest that the vision of an HBCU president must be formally and informally disseminated not only to faculty, staff and students of the institution, but also to the public at large in order to realize the vision and goals set by both the president and administrators of HBCUs.

This thesis examines the extent and patterned use of alcohol and other drugs on the campus of the University of Arkansas at Pine Bluff (one of the Historically Black Colleges and Universities in the United States) during the fall of 1990. The sample consisted of 245 upper (N=73) and lower (N=167) level students; 126 males and 119 females. The study has two major objectives: (1) The construction of a profile of the sample along three dimensions (demographic characteristics, use of alcohol and other drugs, and awareness of alcohol and other drugs); and, (2) Testing of the following hypotheses: (1) College students use alcohol more frequently for social reasons than for relieving tension or depression; (2) Males use alcohol more frequently than females; (3) Males consume alcohol in larger quantities than females in any one usage situation; (4) Students with a stronger sense of well-being (as measured on the Generalized Content Scale and Index of Self-Esteem) use drugs and alcohol less frequently than those with a weaker sense of well-being; (5) Alcohol and drug users have more positive attitudes toward alcohol and drugs than do non-users; (6) Students whose parents use drugs and alcohol, use alcohol and drug more frequently than do students whose parents do not use drugs; and. (7) Students who are products of two-parent families use alcohol and drugs less frequently than those who are products of a one-parent family. Hypotheses 1.2, and 3 were confirmed and 6 was partially confirmed. The most significant finding was that the use of alcohol and drugs constituted no major campus problem. A very small proportion used alcohol regularly or heavily and a minuscule number used other drugs. Furthermore, all students used alcohol and drugs for social rather than psychological reasons.

The college graduation rates for African-Americans, as compared to other ethnic cohorts, remains at a continuous low level. According to the National Center for Education Statistics (2014), 1,602,480 baccalaureate degrees were conferred nationwide to college students during 2009-2010. The purpose of this phenomenological research study is to understand how second-year African-American males attending a mid-sized, southwestern historically Black university and college (HBCU) perceived their ability to achieve academic success. For this study, I collected, thematically analyzed and correlated data from participant profile sheets, focus group meetings, follow-up interviews and observational field notes. The 11 research participants provide a descriptive account of their academic experiences as they have progressed towards their impending graduations. Data analysis rendered six emergent themes: family influence, cultural awareness and exposure, mentorship, networking, academic achievement, and campus climate. This study is significant for individuals who are interested in improving the academic advancements of African-American males in higher education. The findings may aid academic researchers, campus administrators, academically focused organizations, faculty, staff, and students in understanding what is needed to develop new programs and campus initiatives that foster African-American males’ achievement. The research findings also add to the body of limited research that is available on the achievement patterns of African-American males attending HBCUs.

Black men who have sex with men (MSM) on Historically Black College/University (HBCU) campuses face a unique set of challenges. In addition to being disproportionately affected by HIV, Black MSM are impacted by risk behavior, stigma, and environmental policies and practices that adversely influence their experiences. The purpose of this study was to explore the experiences of Black MSM at a HBCU and how stigma, culture, social practices and the collegiate environment impact HIV risk-taking behavior. Utilizing the ecological framework and qualitative analysis, the behaviors of 13 Black MSM on a HBCU campus were examined. Personal interviews and risk assessment questionnaires were analyzed utilizing the phenomenological inquiry method. Data were inductively coded and combined into themes using a qualitative data analysis computer software package. The findings revealed that these 13 participants perceived that HIV-related risk behavior is occurring. They also noted a stigma within the current culture and expressed feelings of marginalization and a negative campus climate from students in the sexual majority. Implications for improving social change from this research include opportunities to (a) establish a culture of social responsibility and consciousness related to the integration and socialization of Black MSM; (b) dialogue regarding the campus climate; and (c) address conscious, unconscious, individual, and environmental stigmas experienced by Black MSM attending this HBCU.

Os métodos para o diagnóstico clínico de câncer de próstata incluem o toque retal e a dosagem do antígeno prostático específico (PSA). Entretanto, o nível de PSA encontra-se elevado em cerca de 20 a 30% dos casos relacionados a patologias benignas, o que resulta em falsos positivos e leva os pacientes a realização de biópsias desnecessárias. O antígeno de membrana prostático específico (PSMA), ao contrário, é sobre expresso no câncer de próstata e encontrado em baixos níveis em órgãos saudáveis. Em razão disso, estimulou-se o desenvolvimento de pequenas moléculas inibidoras do receptor de PSMA, que carreguem agentes de imagem ao tumor e que não sejam prejudicadas pela microvasculatura deste. Estudos recentes sugerem que o quelante HBED-CC contribui intrinsicamente para a ligação do peptídeo inibidor de PSMA baseado em ureia (Glu-ureia-Lys) ao grupo farmacofórico. Este trabalho descreve os estudos de otimização das condições de radiomarcação do PSMA-HBED-CC com 68Ga, utilizando sistema automatizado (módulo de síntese) e método não automatizado, buscando estabelecer uma condição adequada de preparação deste novo radiofármaco, com ênfase no rendimento da marcação e na pureza radioquímica do produto. Também objetivou avaliar a estabilidade do peptídeo radiomarcado em condições de transporte e estudar a distribuição biológica do radiofármaco em camundongos sadios. O estudo dos parâmetros de radiomarcação possibilitou definir um método não automatizado que resultou em alta pureza radioquímica (> 95%), sem a necessidade de purificação do radiomarcado. Já o método de marcação automatizado foi adaptado para utilizar módulo de síntese e software já disponíveis no IPEN, e também resultou em rendimento de síntese elevado (≥ 90%) e superior aos descritos em literatura, com a vantagem associada de maior controle do processo produtivo em atendimento aos requisitos de Boas Práticas de Fabricação. O estudo dos parâmetros de radiomarcação permitiu a obtenção do PSMA-HBED-CC-68Ga com atividade específica superior à utilizada em estudos clínicos publicados (≥ 140,0 GBq/μmol), com estabilidade suficientemente longa, que permitirá o transporte às clínicas para aplicação na obtenção de imagens diagnósticas. Os perfis de biodistribuição e farmacocinético do peptídeo radiomarcado foram compatíveis com os encontrados na literatura. Conclui-se que o PSMA-HBED-CC-68Ga, é uma importante ferramenta de diagnóstico do câncer de próstata por imagem PET, pode ser produzido tanto por método automatizado ou não automatizado, com alta pureza radioquímica, alto rendimento de síntese e estabilidade do radiofármaco.
The methods for clinical diagnosis of prostate cancer include rectal examination and the dosage of the prostatic specific antigen (PSA). However, the PSA level is elevated in about 20 to 30% of cases related to benign pathologies, resulting in false positives and leading patients to unnecessary biopsies. The prostate specific membrane antigen (PSMA), in contrast, is over expressed in prostate cancer and founded at low levels in healthy organs. As a result, it stimulated the development of small molecule inhibitors of PSMA, which carry imaging agents to the tumor and are not affected by their microvasculature. Recent studies suggest that the HBED-CC chelator intrinsically contributes to the binding of the PSMA inhibitor peptide based on urea (Glu-urea-Lys) to the pharmacophore group. This work describes the optimization of radiolabeling conditions of PSMA-HBED-CC with 68Ga, using automated system (synthesis module) and no automated method, seeking to establish an appropriate condition to prepare this new radiopharmaceutical, with emphasis on the labeling yield and radiochemical purity of the product. It also aimed to evaluate the stability of the radiolabeled peptide in transport conditions and study the biological distribution of the radiopharmaceutical in healthy mice. The study of radiolabeling parameters enabled to define a non-automated method which resulted in high radiochemical purity (> 95 %) without the need for purification of the labeled peptide. The automated method has been adapted, using a module of synthesis and software already available at IPEN, and also resulted in high synthetic yield (≥ 90%) specially when compared with those described in the literature, with the associated benefit of greater control of the production process in compliance with Good Manufacturing Practices. The study of radiolabeling parameters afforded the PSMA-HBED-CC-68Ga with higher specific activity than observed in published clinical studies (≥ 140,0 GBq/μmol), with a sufficiently long stability, which will enable transport to clinics for use in diagnostic imaging. Biodistribution and pharmacokinetic profiles of the radiolabeled peptide were consistent with those founded in the literature. We concluded that PSMA-HBED-CC-68Ga, important diagnostic tool for prostate cancer imaging with PET, can be produced by either automated or not automated method with high radiochemical purity, high synthetic yield and stability of the radiopharmaceutical.

In der humanen Haut spielen antimikrobielle Peptide (AP) bei Entzündungsgeschehen bakteriellen und nicht-bakteriellen Ursprungs eine bedeutende Rolle. Neben einer konstitutiven Expression AP können Zytokine deren vermehrte oder abgeschwächte Expression bewirken. In dieser Arbeit wurden die AP humanes β-Defensin (HBD) -2, HBD-3 und Psoriasin (PSO) in Bezug auf deren Expression in gesunder Haut und deren Modulation durch Zytokine in vivo anhand des xenogenen NOD-SCID-Maus-Transplantationsmodells untersucht. Nach erfolgreicher Transplantation von humaner Haut auf NOD-SCID Mäuse wurden die Zytokine TNF-α, IFN-γ und IL-13 in unterschiedlicher Dosierung einzeln und in Kombination intradermal appliziert. Für TNF-α konnte eine erhöhte Expression von HBD-2, HBD-3 und PSO auf RNA-Ebene mittels in-situ-Hybridisierung und Protein-Ebene mittels immunhistochemischer Nachweismethoden gezeigt werden. Eine erhöhte Expression nach Injektion von IFN-γ ließ sich für HBD-3 auf RNA-Ebene und Protein-Ebene und für HBD-2 auf RNA-Ebene erfolgreich belegen. PSO zeigte auf Protein-Ebene nach Modulation mit IFN-γ eine bei höherer Dosierung leicht abnehmende Expression. Eine Änderung der Expression durch IL-13 ließ sich nicht eindeutig belegen. In dieser Arbeit konnte die in der Literatur in vitro beschriebene Modulationsfähigkeit der untersuchten AP durch die verwendeten Zytokine in vivo belegt werden.

The Purpose of this thesis is to briefly describe the company but also the whole branch of soft drinks production. The Dissertation investigate financial structure and analyzes the company through particular instruments of financial analysis such as absolute and ratio indexes, Du Pont decomposition, Altman index, Model IN and Economic value added. Also comparison with the biggest and most dangerous competitors on the market is the other essential part. Output of this thesis presents the evaluation of the financial health and condition of the company, its market position and last but not least some little recommendations, if needed.

This thesis deals with the business strategy in the Chinese market, which is introduced a concrete example of the business strategy of Coca-Cola. According the breadth of the topic there is not included the overall business strategy of mentioned company, but corporate social responsibility, which is the third pillar of the strategy. The aim is to compare by values of social responsibility and setting the Coca-Cola's current situation on the Chinese market and local governments attitude to the main problems of this area. The first chapter is describe the economic growth and current economic development of China, which is marked by the global financial crisis. In the context of sustainable development of Coca-Cola is worth mentioning the Convention and the obligations arising from the country for membership in the ILO. This issue is devoted to the second chapter. The last chapter describes the business strategy (including the basic pillars of the strategy "4A"), with a focus on ensuring sustainable growth. This information is used not only to approach the business strategy, but also for possible access to government compared with the real situation in the country.

Nous avons mis au point et comparé différentes techniques chromatographiques de purification de la capside du virus de l'hépatite B (antigène HBc). L'antigène HBc obtenu a été utilisé pour préparer des anticorps monoclonaux murins anti-HBc, dont trois ont été caractérisés plus en détail. Un des trois anticorps monoclonaux a été utilisé dans un test immuno-enzymatique de recherche de l'antigène HBc, ainsi que pour la réalisation de tests immuno-enzymatique permettant de mettre en évidence la présence d'Ig A et d'Ig E anti-HBc par immunocapture. Les Ig A et les Ig E anti HBc ont pu être mises en évidence à la phase aigüe de l'hépatite B aigüe, que ce soit pour les formes graves ou bégnines, selon une cinétique proche de celles des Ig M anti-HBc (disparition à la convalescence). Dans les formes chroniques d'hépatite B, les taux d'Ig A et d'Ig E anti-HBc observés vont de pair avec la gravité des lésions hépatiques ; les Ig A et Ig E anti-HBc semblent donc être des marqueurs sérologiques particulièrement intéressants pour suivre l'évolution des hépatites chroniques.

This study examines the role of Afrocentric curricula in higher education. Using four HBCU institutions (Dillard University, Hampton University, Howard University, and Spelman College) as a case study, the researcher selected the institutions on the basis of program quality and geographical spread. Program quality means the institutions must be accredited; geographical spread implies that the institutions must represent different parts of the country where HBCUs are concentrated. A mixed methods approach was used to analyze the data gathered from each institution’s course catalog during the 2011-2012 school year. The purpose was to determine if curricula dedicated to the black experience existed. The study found that all of the four institutions offered Afrocentric curricula. However, the courses vary in terms of their breadth, scope, and function. The conclusion drawn from the findings suggests that although the offering of Afrocentric curricula supports the goal of African-centeredness at each HBCU, the offerings are not widespread enough to bolster the HBCUs’ goal of dedication to leadership in the black community as mentioned in the institutions’ mission statements. In an attempt to address the gap between the HBCUs’ mission statements and what the collected data demonstrated, the researcher offered curriculum recommendations designed to enhance the effectiveness of the HBCUs as they promote black leadership in the community.

The purpose of this study was to examine attitudes and general knowledge of Affirmative Action in higher education admissions at one HBCU in Tennessee. The researcher used a modified version of the Echols’s Affirmative Action Inventory (EAAI) to assess attitudes and general knowledge of all administrators, faculty, staff, and students at this institution. At the conclusion of the collection period, 269 surveys were deemed usable. Of these, 31 surveys were completed by administrators, faculty completed 62 surveys, 55 surveys were completed by staff, and 121 surveys were completed by students. The dependent variables for the study were individual survey questions (1-9) and three dimensions created by transforming the data from sets of survey questions. The independent variables were participant group (administrators, faculty, staff, and students), gender, race, and academic discipline. Two-way contingency tables and c2 were used to examine the associations between each independent variable and the dependent variable for each of the individual survey questions. Two-way analysis of variance (ANOVA) was used to compare the mean differences between the dimensions and pairs of independent variables. The quantitative findings indicated that the independent variable, participant group, was found to differ in five of the 11 research questions significantly. Administrators hold positive attitudes and exhibit greater general knowledge on the topic of Affirmative Action compared to faculty, staff, or students. Of the other independent variables, only race and academic discipline resulted in significant differences. Respondents who identified as Non-White exhibited positive attitudes towards the dimension that assessed whether Affirmative Action was moral and ethical over respondents who identified as White. Respondents who were classified as belonging to the humanities (academic discipline) were more likely to exhibit positive attitudes toward support of Affirmative Action over respondents who were classified as belonging to business.

O reconhecimento facial automático é uma tarefa muito importante para a sociedade moderna, pois possibilita o desenvolvimento de diversas aplicações, tais como o controle de imigração em aeroportos, a autenticação de documentos, etc. Muitas destas aplicações ocorrem em ambientes não controlados, onde as fotos são obtidas com grandes variações de poses e expressões faciais, de iluminação, no uso de maquiagem e acessórios, etc. A tarefa de reconhecimento facial automático em ambientes não controlados é ainda muito desafiadora e tem sido alvo de muitas pesquisas no mundo todo nos últimos anos. Dentro deste contexto, esta tese propõe e implementa um conjunto de novos métodos que visam contribuir para o avanço do estado da arte relacionado a este tema de pesquisa. Inicialmente foi proposto o HBWLF, um filtro para enfatizar as componentes de alta frequência da imagem, sem eliminar as de baixa, realçando assim os diversos detalhes das imagens faciais. Em seguida foi proposta uma versão mais geral deste filtro, o MHBWLF, que considera uma vizinhança circular, ao invés de uma grade regular de 3x3 pixels. O MHBWLF foi aplicado em conjunto com um filtro MOSSE no desenvolvimento de um método para a localização precisa dos centros dos olhos. Aproveitando as características do MHBWLF e inspirado em outros descritores foi proposto um novo descritor, o HBWD. Por fim, foi introduzido um novo método de reconhecimento facial, baseado no HBWD. O método proposto emprega o HBWD para descrever densamente a região periocular e, a fim de reduzir a dimensão dos dados, foi proposto um algoritmo de mapeamento baseado no método de agrupamento k-Means++. Os métodos propostos foram todos avaliados utilizando-se imagens das bases LFW, FGLFW e BioID e os resultados experimentais obtidos mostram que os métodos propostos tem desempenho superior a vários outros métodos estado da arte.
The task of automatic face recognition is very important for modern society and very useful for many kind of applications, such as automatic recognition of credit card users, document authentication, security in big events and others. Further, this is a challenging task when performed in uncontrolled scenarios, which involve great variations in imaging conditions such as illumination, poses and facial expressions, partial occlusion due to hair or glasses, makeup, etc. This thesis first introduces the new High-Boost Weber Local Filter (HBWLF) that emphasizes high-frequency components, without eliminating the low-frequency ones, and thus enhances the details of a face. It is also introduced the new MHBWLF (Multiscale High-Boost Weber Local Filter), which is a multiscale version of HBWLF. A new method for precise eye localization is presented, where a MOSSE filter is used for learning the features enhanced by MHBWLF. This thesis also introduces a new local descriptor called HBWD (High-Boost Weber Descriptor) which combines some features of MHBWLF, SIFT and CS-LMP. Finally, a new method of face recognition is presented. The proposed method basically detects the faces, localizes their eyes and performs a face alignment. After that the region of interest (ROI) is more accurately cropped and described using the new HBWD in a dense sampling scheme (sampling each pixel). A new algorithm, based on the known clustering method k-Means++, reduces the dimensionality of the HBWD descriptors densely applied on each ROI, and produces a signature for the image pair being compared. Finally, a SVM is used to classify the images as a matched or mismatched pair. The proposed methods were evaluated using images from the well-known LFW, FGLFW and BioID databases and the experimental results show that the proposed methods outperform other state-of-the-art approaches.

Gaining admissions into higher education is not nearly as challenging as persisting to degree attainment. Promising black students are failing to complete higher education pursuits, but what can institutions of higher education do to reverse this trend, particularly in the HBCU environment, where the average graduation rate is 42% (Journal of Blacks in Higher Education, 2008)? The purpose of this study is to examine the relationship intent to persist and actual persistence may have with ability-to-pay, socioeconomic status, and other selected variables at a private, highly selective, urban, HBCU. Pearson Correlation was utilized to analyze survey and student record data collected from 245 study participants. The implications of not persisting in education, whether in P-12 or higher education are far reaching and impact individuals as well as communities. This study seeks to identify the variables that most impact intent to persist and actual persistence at a private, highly selective, urban, HBCU.

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O papilomavírus humano (HPV) é um dos mais importantes agentes etiológicos envolvidos no desenvolvimento do câncer cervical. Dois dos principais fatores de risco envolvidos no desenvolvimento dessas neoplasias malignas são infecção pelo HPV e co-infecção com doenças sexualmente transmissíveis. O sistema imunológico é responsável pelo reconhecimento e eliminação de substâncias estranhas. A proteína ligadora de manose (MBL) é uma proteína sintetizada no fígado, sendo uma das vias de ativação do sistema complemento. Polimorfismos dentro da região gênica/promotora da MBL afetam a quantidade desta proteína dentro do soro, sendo associada com um importante elemento no aparecimento de várias doenças infecciosas. O gene hBD-1 é um candidato a um gene supressor tumoral encontrado alterado em 90% de câncer renal e 82% de câncer de próstata e polimorfismos dentro da região promotora têm sido associados à susceptibilidade a várias infecções virais. Sendo assim, o presente estudo teve como objetivo verificar a existência de correlação entre polimorfismo do gene da MBL-2 e do gene da β -defensina-1 com a susceptibilidade às infecções por HPV, HIV e HPV/HIV através da metodologia da PCR em tempo real. Os resultados obtidos não demonstraram associação dos polimorfismos do gene MBL-2 nos grupos estudados (HIV positivo, HPV positivo, HPV/HIV positivos). Em relação ao polimorfismo da região -44 do gene HBD-1, verificou-se associação com a susceptibilidade apenas à infecção pelo HIV entre os grupos analisados

The fear of crime is analyzed on six college and university campuses that make up the Atlanta University Center (AUC). The study utilizes interview questionnaire data on 325 students attending AUC institutions which were collected during the spring semester of 1993. The analytical procedures used include the reliability analysis, frequency distributions, cross tabulations and chi-square tests. The data analysis did not reveal any significant relationships between fear of crime and demographic characteristics except for gender of the students. Also, there was no significant relationship between fear of crime and prior victimization. However, the relationship between fear of crime and constrained behavior was significant. On the whole, it was evident that fear of crime increases the probability of constrained behavior, which in turn reduces victimization.

The lived experiences of African American lesbians who attended historically Black colleges and universities (HBCUs) have not received sufficient empirical attention; therefore, this study was conducted to understand and describe their experiences. The study followed a qualitative phenomenological approach. The multidimensional identity model, developed by Reyolds and Pope, was used as the framework through which to understand the participants' experiences. Semistructured, 40 to 60-minute interviews were conducted with 6 women who identified as African American lesbians and attended HBCUs. Initial hand and subsequent NVivo coding of interview data led to the development of the following 7 themes: (a) either African American women or African American lesbian, (b) fear of rejection, (c) chosen kin, (d) no benefit of being an African American lesbian at an HBCU, (e) love for the African American community, (f) women who love women, and (g) the road not taken. The findings suggest African American lesbians often shift between identities, depending on the situation or setting. The results of the study provide suggestions for counselors and counselor educators who will be able to increase their understanding of the unique needs of individuals who identify with at least 3 marginalized communities. African American lesbians who attend HBCUs may benefit from this inquiry as HBCUs can use the information in this study to help create and sustain a more inclusive campus environment. Additional implications for social change and future research are included at the end of the study.

Introdução. A infecção causada pelo vírus da hepatite B (HBV) é um dos agravos de maior prevalência no mundial. Segundo a Organização Mundial da Saúde (OMS) existem mais de 350 milhões de portadores crônicos da doença. A infecção pelo HBV é rotineiramente identificada quando há a presença do HBsAg circulante. Entretanto, em alguns casos o HBV-DNA tem sido detectado em indivíduos HBsAg negativos, positivos ou negativos para anti-HBc e anti-HBs. Essa apresentação sorológica e molecular é denominada infecção oculta pelo HBV (OBI). Geralmente a concentração do HBV-DNA no soro será abaixo de 200 UI/mL. Objetivo: Determinar a prevalência da OBI, em doadores de sangue do Estado do Amapá no ano de 2014. Material e Métodos. Foram analisadas um total de 62 amostras de doadores de sangue do estado do Amapá, no ano de 2014, que apresentavam o perfil sorológico: HBsAg negativo, anti-HBc positivo e com anti-HBs negativo ou positivo. Os marcadores sorológicos HBsAg e anti-HBc foram determinados através do imunoensaio quimioluminescente. As amostras selecionadas para a detecção do HBV-DNA foram testadas utilizando as metodologias de Real-Time PCR Kit NAT HIV/HCV/HBV (Bio-Manguinhos®) e PCR \"in house\". Resultados. Do total de 13.261 doadores triados para infecções transmissíveis pelo sangue, 283 apresentaram resultados reagentes para os marcadores da hepatite B, nos quais: 35 (0,3%) foram HBsAg e 248 (1,9%) para anti-HBc reagentes. Um total de 62 amostras foram testadas pelos métodos moleculares. Todas as amostras apresentaram resultado HBV-DNA não-detectável. Conclusão: O índice de inaptidão sorológica no ano de 2014 no HEMOAP foi de 1,9% para anti-HBc e 0,3% para HBsAg. A população estudada foi constituída predominantemente por adultos com idade entre 29-65 anos, do sexo masculino, casados e naturais de municípios do estado do Amapá
Introduction. The infection caused by the hepatitis B virus (HBV) is one of the most prevalent diseases in the world. According to the World Health Organization (WHO) there are more than 350 million chronic carriers of the disease. HBV infection is routinely identified when there is presence of circulating HBsAg. However, in some cases HBV-DNA has been detected in HBsAg negative individuals, positive or negative for anti-HBc and anti-HBs. This serological and molecular presentation is termed HBV-occult infection (OBI). Usually the concentration of HBV-DNA in serum will be below 200 IU / mL.Objective: To determine the prevalence of OBI in blood donors, in the State of Amapá, in the 2014. Material and methods. A total of 62 samples of blood donors from the State of Amapá in the year 2014 were analyzed, presenting the serological profile: HBsAg negative, anti-HBc positive and with negative or positive anti-HBs. Serum markers HBsAg and anti-HBc were determined by the chemiluminescent immunoassay. Samples selected for HBV-DNA detection were tested using the Real-Time PCR Kit Kit HIV / HCV / HBV (Bio-Manguinhos®) and in-house PCR. Results. Of the total of 13,261 donors screened for blood-borne infections, 283 presented reactive results for hepatitis B markers, in which: 35 (0.3%) were HBsAg and 248 (1.9%) for anti-HBc reagents. All samples showed nondetectable HBV-DNA result. Conclusion: The serological disability index in the year 2014 in HEMOAP was 1.9% for anti-HBc and 0.3% for HBsAg. The studied population consisted predominantly of adults aged 29-65 years, males, married and natural of cities of the state of Amapá

The content of this thesis is an analysis of a selected work team in the company Coca-Cola HBC Czech Republic Ltd. The main aim of the work is to provide materials and recommendations to the team manager helping him improve the teamwork effectiveness and develop the team. In the introductory part of the thesis theoretical principles related to teamwork are presented. The next part deals with processing methodology of empirical investigation. The practical part is focused on the analysis of work team and provides recommendations for improving the effectiveness of teamwork and team development.

Die vorliegende Dissertation berichtet über die Untersuchung von selbst-aggregierten Einfach- und Mehrfachschichten aus Nanographenen-Derivate mit Hilfe der Rastertunnelmikroskopie (RTM) an Fest-Flüssig-Grenzflächen. Die -Konjugation bringt einzigartige elektronische Eigenschaften mit sich, so dass die Nanographen-Derivate viel versprechende Bausteine für eine molekulare und organische Elektronik sind, da sie maßgeschneidert und kostengünstig prozessiert werden können, und leicht und flexibel sind. Für elektronische Anwendungen ist es notwendig, die Nanographene in ultradünnen Filmen mit geordneten supramolekularen Strukturen zu organisieren. Nanostrukturen werden für Nanographene-Derivate auf hoch orientiertem pyrolytischem Graphit (HOPG) untersucht, wie zum Beispiel alkylierte Hexi-peri-hexabenzocoronene (HBCs) unterschiedlicher Symmetrie und dreiecksförmige polyzyklische aromatische Kohlenwasserstoffe (PAK). Es zeigt eine erstaunliche Vielfalt von supramolekularen Strukturen, z.B. Zick-Zack-, Blumen- oder Honigwaben-Muster. Eine faszinierende Besonderheit besteht in den Honigwaben Strukturen, die sich durch Selbstaggregation dreieckiger alkylierter Phenyl-PAKs bilden, und die damit Nanotemplate für Gastmoleküle darstellen. In vielen Fällen bilden Nanographene-Derivate nicht nur Monoschichte sondern auch Multischichten auf Graphit. Die Selbstorganisation von Doppelschichten aus einer HBC-Stern-Verbindung bietet das Potenzial für Baustelemente in der organischen Elektronik, zum Beispiel für Nanodrähte. Die alkylierten Phenyl-HBCs bilden polykristalline Strukturen sowohl in der "face-on"-Anordnung in Monoschichten auf Graphit wie in der "edge-on"-Anordnung in Multischichten, die sich in einem äußeren elektrischen Feld bilden. Beides kann nützlich sein, da für die mögliche Anwendung in einer Photovoltaik-Zelle die "face-on"-Orientierung auf Oberflächen erforderlich ist, während für organische Feldeffekt-Transistoreneine "edge-on" Nanostruktur benötigt wird.
This thesis reports on the investigation of self-assembled mono- and multilayers from nanographene derivatives via scanning tunneling microscopy (STM) at solid-liquid interfaces. Because of the unique electronic properties associated with their -bonded topology, nanographenes are promising building blocks for molecular and organic electronics, which provide the possibility of tunability together with low-cost processing, light weight, and flexibility. For the application in electronics it is necessary to organize nanographenes in ultrathin films with well-ordered supramolecular structures. Nanostructures of monolayers on Highly Oriented Pyrolytic Graphite (HOPG) are studied for different nanographene derivatives, such as alkylated hexa-peri-hexabenzocoronenes (HBCs) with different symmetries, and triangle-shaped polycyclic aromatic hydrocarbons (PAHs). They exhibit a surprising diversity of supramolecular structures, for example zigzag, flower-like or honeycomb shapes. A fascinating peculiarity provides the honeycomb structures which are self-assembled from triangle-shaped alkylated phenyl PAHs, which provide nanotemplates to accommodate guest molecules. In many cases, nanographene derivatives not only form monolayers but also multilayers on HOPG. Star-shaped HBC molecules self organize into bilayers in polar solvents, which exhibit the potential for the formation of building blocks of organic electronics, for instance nanowires. The alkylated phenyl HBCs form polycrystalline structures both in the “face-on” arrangement in a monolayer on HOPG, and “edge-on” in multilayers within an external electric field. Both may be useful for potential applications, since in a photovoltaic cell, the “face-on” orientation on surfaces is required, while for the purpose to be applied in organic field-effect transistors, the “edge-on” nanostructure on the electrodes is necessary.

The purpose of this study was to examine the adjustment experiences of African American graduates of historically Black colleges or universities (HBCUs) attending graduate school at a Southern predominantly White university (PWU). A discussion of narratives and themes across participants provided information about the adjustment experiences of African American graduate students who transitioned from a university community where the student population was predominantly African American to one where African American students were the minority. This information can be utilized by both PWUs and HBCUs to develop resources that address issues related to adjustment for African American graduate students. This study was phenomenological by design and focused on analyzing the adjustment experiences of 11 female African American graduate students attending a Southern PWU. Participants were between the ages of 22-28, graduated from 10 different HBCUs across 8 states, represented 8 different graduate majors and had been in graduate school an average of 3.5 semesters. Research methodology included participant interviews, demographic questionnaires and investigator field notes. Collected data were analyzed using a coding iteration strategy. Descriptions of participant experiences were documented and ten prominent themes emerged from the data: support systems, negative emotionality, distrust, academic frustration, lack of African American presence, non-cohesive African American community, racial microaggressions, prior acquaintances and resilience.
Ph. D.

Historically Black Colleges and Universities (HBCUs) were established with the main objective of identifying and empowering people of African descent. Over the years, these institutions have grown, enrolling 16% of Black high school graduates and during graduation, almost 20% of African-American graduates. Using a qualitative study design, the main goal of this study was to identify the effectiveness of HBCUs’ ability to serve the interests and needs of African-American students who chose to attend and graduate from HBCUs as undergraduate students then attend and graduate from graduate schools at predominantly White institutions (PWIs.) This study inquired about focusing on the factors influencing how undergraduate students make decisions on which college to attend, what factors influence their career selection, and the impact the university experience has on future careers and overall college experience. Data was gathered from African-American HBCU graduates who then attended and graduated from PWIs in California. Interviews and online surveys were conducted with participants to collect in-depth responses regarding their experiences, views, beliefs, and motivations. The sample comprised 100 respondents out of an original 200 who were selected. The study showed that many participants attended their chosen colleges because they preferred to associate with people who shared origins like their own. Family and friends were found to be influential in college selection and educational background influenced the types of careers study participants pursued after graduation from college. Implications for future research are discussed.

Academic persistence among African American college students has become an important issue due to the consistent lack of increase in the retention rates of these students. Despite the importance of this issue in the field of education, little has been done to study how family factors may influence college studentâ s academic success from a family science perspective. Further, students attending HBCUs are rarely utilized in empirical research even though HBCUs have proven to be effective in graduating African American students. The purpose of this qualitative study was to examine the ways in which African American college studentsâ perceive family relationships and support as impacting their academic persistence. Fourteen African American college students attending an HBCU were interviewed about their perceptions of the impact of family relationships and support on their academic persistence. Participants included nine females and five males all identifying as juniors or seniors. Findings for the study included four major themes: (a) family structure and family relationships, (b) challenges/overcoming obstacles, (c) coping strategies, and (d) success and perseverance. Family structure and relationships were defined in a variety of ways by participants, which included immediate family, non-kin, and extended family. Participants faced several challenges and obstacles including transitioning to college, family issues at home, and being a burden, particularly financially, on other family members. Several coping strategies were utilized by participants. Family support, religiosity, peer relationships, and music were cited most often by participants in this study. The study concluded that family relationships and support are indeed important in academic persistence of African American college students.
Ph. D.

This study sought to examine the outcome of teacher education candidates’ performance on a state content exam. Seventeen participants from the class of 2012 were identified for the study of which 12 participants fully participated in the study. This study utilized data collected from the participants through the Teacher Quality Enhancement Subcontract Grant Summer/Fall/Spring 2011-2012 Workshop Series held at the private HBCU. The research design used a QUAN- QUAL-QUAN to triangulate the data through three methods of data collection: GACE early childhood education (ECE) data, GACE ECE survey questionnaire and class of 2012 member interviews. The first QUAN correlations were run on the 17 participants. The survey instrument (qualitative and descriptive statistical constructs) was completed by 12 participants. The last QUAN correlations were run on the 12 participants who completed the survey instrument. Correlation analysis was used to determine if a significant relationship existed between the independent variables (Scholastic Aptitude Test (SAT), American College Testing (ACT), high school grade point average (HSGPA), grade point average prior to preservice teaching (GPAPST), cumulative grade point average (CGPA), number of failed attempts test # 001, number of failed attempts test # 002) and dependent variables (GACE ECE test # 001 pass or fail, GACE ECE test # 002 pass or fail, exam first time pass or fail). Descriptive statistical analyses were extrapolated from the selected Likert scaled items collected from the survey instrument to test selected research questions. The findings from the survey items related to program quality for the participants’ mean was 3.05 (n =12) on a 1 to 5 Likert scale. The findings from the survey items related to motivation for the participants’ mean was 4.35 (n=12) on a 1 to 5 Likert scale. A limitation was the total participants that were available for the case study of majors for the degree in the class of 2012 (n = 17). Correlation analyses revealed a statistically significant relationship between first time pass or fail and number of failed attempts on #001; first time pass or fail and number of failed attempts on #002; test failures after first attempt on test #001 and SAT; test failures after first attempt on test #002 and SAT; program quality and GPAPST; first time pass or fail rate and perception of program quality. Recommendations for future studies include a concentrated study from public and private HBCUs and or minority serving institutions with teacher preparation programs enrolling more than 30 candidates of color in their graduating classes.