Synthesis of 15N-enriched urea (CO(15NH2)2) from 15NH3, CO, and S in a discontinuous process

CO(15NH2)2 enriched with the stable isotope 15N was synthesized based on a reaction involving CO, 15NH3, and S in the presence of CH3OH. The method differs from the industrial method; a stainless steel reactor internally lined with polytetrafluoroethylene (PTFE) was used in a discontinuous process under low pressure and temperature. The yield of the synthesis was evaluated as a function of the parameters: the amount of reagents, reaction time, addition of H2S, liquid solution and reaction temperature. The results showed that under optimum conditions (1.36, 4.01, and 4.48 g of 15NH3, CO, and S, respectively, 40 ml CH3OH, 40 mg H2S, 100 ºC and 120 min of reaction) 1.82 g (yield 76.5%) of the compound was obtained per batch. The synthesized CO(15NH2)2 contained 46.2% N, 0.55% biuret, melting point of 132.55 ºC and did not exhibit isotopic fractionation. The production cost of CO(15NH2)2 with 90.0 at. % 15N was US$ 238.60 per gram.

Bromatological characteristics and in vitro digestibility of four sugarcane varieties subjected or not to the application of quicklime

The experiment was conducted to evaluate the bromatological characteristics and the in vitro digestibility of four sugarcane varieties, subjected or not to hydrolysis, with quicklime. A completely randomized design was employed with three replications arranged in a 4 × 2 factorial scheme, with four sugarcane varieties (SP 52454, RB 867515, RB 855536 and IAC 862480), hydrolyzed or not. There was significant effect on brix (p < 0.05) and industrial fiber (p < 0.05), and IAC 862480 variety had the lowest levels of industrial fiber. There were no significant difference (p > 0.05) in neutral detergent fiber, acid detergent fiber and lignin levels among the sugarcane varieties under analysis and for the sugarcanes, hydrolyzed or not. The use of sugarcane hydrolysis with 1% quicklime improves the in vitro digestibility of NDF and ADF, regardless of the variety studied. Hydrolysis with 1% quicklime did not alter the sugarcane chemical composition.

Compressive strength of dental composites photo-activated with different light tips

The aim of this study was to evaluate the compressive strength of microhybrid (FiltekTM Z250) and nanofilled (FiltekTM Supreme XT) composite resins photo-activated with two different light guide tips, fiber optic and polymer, coupled with one LED. The power density was 653 mW cm-2 when using the fiber optic light tip and 596 mW cm-2 with the polymer. After storage in distilled water at 37± 2 °C for seven days, the samples were subjected to mechanical testing of compressive strength in an EMIC universal mechanical testing machine with a load cell of 5 kN and speed of 0.5 mm min-1. The statistical analysis was performed using ANOVA with a confidence interval of 95% and Tamhane’s test. The results showed that the mean values of compressive strength were not influenced by the different light tips (p > 0.05). However, a statistical difference was observed (p < 0.001) between the microhybrid composite resin photo-activated with the fiber optic light tip and the nanofilled composite resin. Based on these results, it can be concluded that microhybrid composite resin photo-activated with the fiber optic light tip showed better results than nanofilled, regardless of the tip used, and the type of the light tip did not influence the compressive strength of either composite. Thus, the presented results suggest that both the fiber optic and polymer light guide tips provide adequate compressive strength to be used to make restorations. However, the fiber optic light tip associated with microhybrid composite resin may be an interesting option for restorations mainly in posterior teeth.

Strength training combined with plyometric jumps in adults: sex differences in fat-bone axis adaptations

[EN] Leptin and osteocalcin play a role in the regulation of the fat-bone axis and may be altered by exercise. To determine whether osteocalcin reduces fat mass in humans fed ad libitum and if there is a sex dimorphism in the serum osteocalcin and leptin responses to strength training, we studied 43 male (age 23.9 2.4 yr, mean +/- SD) and 23 female physical education students (age 23.2 +/- 2.7 yr). Subjects were randomly assigned to two groups: training (TG) and control (CG). TG followed a strength combined with plyometric jumps training program during 9 wk, whereas the CG did not train. Physical fitness, body composition (dual-energy X-ray absorptiometry), and serum concentrations of hormones were determined pre- and posttraining. In the whole group of subjects (pretraining), the serum concentration of osteocalcin was positively correlated (r = 0.29-0.42, P < 0.05) with whole body and regional bone mineral content, lean mass, dynamic strength, and serum-free testosterone concentration (r = 0.32). However, osteocalcin was negatively correlated with leptin concentration (r = -0.37), fat mass (r = -0.31), and the percent body fat (r = -0.44). Both sexes experienced similar relative improvements in performance, lean mass (+4-5%), and whole body (+0.78%) and lumbar spine bone mineral content (+1.2-2%) with training. Serum osteocalcin concentration was increased after training by 45 and 27% in men and women, respectively (P < 0.05). Fat mass was not altered by training. Vastus lateralis type II MHC composition at the start of the training program predicted 25% of the osteocalcin increase after training. Serum leptin concentration was reduced with training in women. In summary, while the relative effects of strength training plus plyometric jumps in performance, muscle hypertrophy, and osteogenesis are similar in men and women, serum leptin concentration is reduced only in women. The osteocalcin response to strength training is, in part, modulated by the muscle phenotype (MHC isoform composition). Despite the increase in osteocalcin, fat mass was not reduced.

Solutions of alkyl methanoates and alkanes: Simultaneous modeling of phase equilibria and mixing properties. Estimation of behavior by UNIFAC with recalculation of parameters.

[EN]Isobaric vapor–liquid equilibria at p = 101.32 kPa (iso-p VLE) and the mixing properties, hE and vE, are determined for a set of twelve binary solutions: HCOOCuH2u+1(1)+CnH2n+2(2) with u = (1–4) and n = (7– 9). The (iso-p VLE) present deviations from the ideal behavior, which augment as u diminishes and n increases. Systems with [u = 2,3 n = 7] and [u =4 , n = 7,8] present a minimum-boiling azeotrope. The nonideality is also reflected in high endothermic values, hE > 0, and expansive effects, vE > 0, for all the binaries, which increase regularly with n

Selektive und duale COX-1-, COX-2-Inhibitoren aus der Reihe der Methanone

Zusammenfassung: Prostaglandine (PG) sind wichtige biologische Entzündungsmediatoren, die aus der Arachidonsäure (AA) durch das Enzym Cyclooxygenase (COX) entstehen. Trotz einiger unerwünschter Wirkungen, sind Cyclooxygenase-Hemmer Mittel der Wahl zur Unterdrückung entzündlicher Prozesse. Von der Cyclooxygenase existieren zwei Isoenzyme: COX-1 und COX-2. Eine selektive Hemmung der COX-2 bzw. eine duale Hemmung der COX-1 und COX-2 wird als erfolgversprechendes Prinzip zur Behandlung von entzündlichen Erkrankungen diskutiert.Ziel der Arbeit war die Synthese und in vitro Testung sowie die Erstellung von Struktur-Wirkungs-Beziehungen selektiver bzw. dualer Hemmstoffe der COX-1/-2. Zusätzlich wurden die Substanzen auf inhibitorische Aktivität gegenüber der 5- und 12-Lipoxygenase untersucht.Ausgehend von der Struktur selektiver Hemmstoffe der COX-2 bzw. von dualen COX-1/ COX-2-Inhibitoren sowie von marktüblichen nichtsteroidalen Antirheumatika (NSAR), wurde das Diarylmethanon-Element als Basis gewählt. An diesem Strukturelement wurden Modifikationen vorgenommen, um selektive Hemmstoffe der COX-2 bzw. duale COX-1/ COX-2-Hemmstoffe zu erhalten.Die synthetisierten Verbindungen lassen sich in [4-(Methylsulfanyl)phenyl]- und [4-(Methylsulfonyl)phenyl](aryl)methanone, N-(Aroylphenyl)sulfonamide und -amide sowie (Hydroxyphenyl)(2-thienyl)methanone unterteilen.In der Reihe der [4-(Methylsulfanyl)phenyl](aryl)methanone sind potente Hemmstoffe sowohl der COX-1 als auch der COX-2 erhalten worden. Im Gegensatz dazu zeigen die [4-(Methylsulfonyl)phenyl](aryl)methanone gegenüber COX-1 und COX-2 keine inhibitorische Aktivität. Mit dem 2-Thienylderivat wurde ein potenter, dualer Hemmstoff beider Cyclooxygenase-Isoenzyme identifiziert, dessen Wirkstärke (bezüglich der COX-2) auf den Austausch von Phenyl gegen 2-Thienyl zurückzuführen ist.Die N-(Aroylphenyl)sulfonamide und -amide bilden die umfangreichste Gruppe bei den durchgeführten Untersuchungen, wobei besonders die regioisomeren N-(2-Aroylphenyl)sulfonamide und -amide eingehender studiert wurden. Auf der Basis der (2-Aroylphenyl)sulfonamide läßt sich für die Hemmung der COX-1 eine Struktur-Wirkungs-Beziehungen formulieren, die anhand Hilfe geeigneter Verbindungen überprüft wurde. Die Untersuchungen wurden zum Teil auch auf die 3- und 4-Regioisomeren ausgedehnt, wobei sich die erhaltenen Struktur-Wirkungs-Beziehungen bestätigten. Die Arylsulfonamide inhibieren bevorzugt die COX-1. Auch (4-Aroylphenyl)sulfonamide wurden auf mögliche inhibitorische Aktivität untersucht. Die Einbindung des Amidstickstoffs in ein Indolin- bzw. Tetrahydrochinolin-Ringsystem oder des Sulfonamids in ein 1,3-Propansultam führte in jedem Falle zu wenig aktiven Verbindungen gegenüber der COX-1. N-(2-Aroylphenyl)amide zeigten in Übereinstimmung mit der Hypothese an der COX-1 eine gute inhibitorische Aktivität.Aus der Reihe der (Hydroxyphenyl)(2-thienyl)methanone wurden die freien Alkohole, die Methylether und verschiedene Ester dargestellt und auf COX-1-Aktivität untersucht. Acetate, aber auch Phenole sind die potentesten Inhibitoren der COX-1. Als günstigte Positionen für die 2-Thienylcarbonyl-Einheit am Hydroxyphenylrest erweist sich die ortho- bzw. para-Position.

Photovoltaics from discotic liquid crystalline HBCs & poly(2,7-carbazole)s

In this study, the use of the discotic liquid crystalline HBCs and conjugated polymers based on 2,7-carbazole were investigated in detail as donor materials in organic bulk-heterojunction solar cells. It has been shown that they perform efficiently in photovoltaic devices in combination with suitable acceptors. The efficiency was found to depend strongly dependent on the morphology of the film. By investigation of a series of donor materials with similar molecular structures based on both discotic molecules and conjugated polymers, a structure-performance relation was established, which is not only instructive for these materials but also serves as a guideline for improved molecular design. For the series of HBCs used in this study, it is found that the device efficiency decreases with increasing length of the alkyl substituents in the HBC. Thus, the derivative with the smallest alkyl mantle, being more crystalline compared to the HBCs with longer alkyl chains, gave the highest EQE of 12%. A large interfacial separation was found in the blend of HBC-C6,2 and PDI, since the crystallization of the acceptor occurred in a solid matrix of HBC. This led to small dispersed organized domains and benefited the charge transport. In contrast, blends of HBC-C10,6/PDI or HBC-C14,10/PDI revealed a rather homogeneous film limiting the percolation pathways due to a mixed phase. For the first time, poly(2,7-carbazole) was incorporated as a donor material in solar cells using PDI as an electron acceptor. The good fit in orbital energy levels and absorption spectra led to high efficiency. This result indicates that conjugated polymers with high band-gap can also be applied as materials to build efficient solar cells if appropriate electron acceptors are chosen. In order to enhance the light absorption ability, new ladder-type polymers based on pentaphenylene and hexaphenylene with one and three nitrogen bridges per repeat unit have been synthesized and characterized. The polymer 2 with three nitrogen bridges showed more red-shifted absorbance and emission and better packing in the solid-state than the analogous polymer 3 with only one nitrogen bridge per monomer unit. An overall efficiency as high as 1.3% under solar light was obtained for the device based on 1 and PDI, compared with 0.7% for the PCz based device. Therefore, the device performance correlates to a large extent with the solar light absorption ability and the lateral distance between conjugated polymer chains. Since the lateral distance is determined by the length and number of attached alkyl side chains, it is possible to assume that these substituents insulate the charge carrier pathways and decrease the device performance. As an additional consequence, the active semiconductor is diluted in the insulating matrix leading to a lower light absorption. This work suggests ways to improve device performance by molecular design, viz. maintaining the HOMO level while bathochromically shifting the absorption by adopting a more rigid ladder-type structure. Also, a high ratio of nitrogen bridges with small alkyl substituents was a desirable feature both in terms of adjusting the absorption and maintaining a low lateral inter-chain separation, which was necessary for obtaining high current and efficiency values.

Measurement of the elastic electron-proton cross section and separation of the electric and magnetic form factor in the Q 2 range from 0.004 to 1 (GeV/c) 2

The electromagnetic form factors of the proton are fundamental quantities sensitive to the distribution of charge and magnetization inside the proton. Precise knowledge of the form factors, in particular of the charge and magnetization radii provide strong tests for theory in the non-perturbative regime of QCD. However, the existing data at Q^2 below 1 (GeV/c)^2 are not precise enough for a hard test of theoretical predictions.rnrnFor a more precise determination of the form factors, within this work more than 1400 cross sections of the reaction H(e,e′)p were measured at the Mainz Microtron MAMI using the 3-spectrometer-facility of the A1-collaboration. The data were taken in three periods in the years 2006 and 2007 using beam energies of 180, 315, 450, 585, 720 and 855 MeV. They cover the Q^2 region from 0.004 to 1 (GeV/c)^2 with counting rate uncertainties below 0.2% for most of the data points. The relative luminosity of the measurements was determined using one of the spectrometers as a luminosity monitor. The overlapping acceptances of the measurements maximize the internal redundancy of the data and allow, together with several additions to the standard experimental setup, for tight control of systematic uncertainties.rnTo account for the radiative processes, an event generator was developed and implemented in the simulation package of the analysis software which works without peaking approximation by explicitly calculating the Bethe-Heitler and Born Feynman diagrams for each event.rnTo separate the form factors and to determine the radii, the data were analyzed by fitting a wide selection of form factor models directly to the measured cross sections. These fits also determined the absolute normalization of the different data subsets. The validity of this method was tested with extensive simulations. The results were compared to an extraction via the standard Rosenbluth technique.rnrnThe dip structure in G_E that was seen in the analysis of the previous world data shows up in a modified form. When compared to the standard-dipole form factor as a smooth curve, the extracted G_E exhibits a strong change of the slope around 0.1 (GeV/c)^2, and in the magnetic form factor a dip around 0.2 (GeV/c)^2 is found. This may be taken as indications for a pion cloud. For higher Q^2, the fits yield larger values for G_M than previous measurements, in agreement with form factor ratios from recent precise polarized measurements in the Q2 region up to 0.6 (GeV/c)^2.rnrnThe charge and magnetic rms radii are determined as rn⟨r_e⟩=0.879 ± 0.005(stat.) ± 0.004(syst.) ± 0.002(model) ± 0.004(group) fm,rn⟨r_m⟩=0.777 ± 0.013(stat.) ± 0.009(syst.) ± 0.005(model) ± 0.002(group) fm.rnThis charge radius is significantly larger than theoretical predictions and than the radius of the standard dipole. However, it is in agreement with earlier results measured at the Mainz linear accelerator and with determinations from Hydrogen Lamb shift measurements. The extracted magnetic radius is smaller than previous determinations and than the standard-dipole value.

Mean curvature flow in SE (2) and applications to visual perception

Our goal in this thesis is to provide a result of existence of the degenerate non-linear, non-divergence PDE which describes the mean curvature flow in the Lie group SE(2) equipped with a sub-Riemannian metric. The research is motivated by problems of visual completion and models of the visual cortex.

Study of 3 Lambda H and 4 Lambda H in the reaction of 6 Li + 12 C at 2 A GeV

Die Produktion von Hyperkernen wurde in peripheren Schwerionenreaktionen untersucht, bei denen eine Kohlenstofffolie mit $^6$Li Projektilen mit einer Strahlenergie von $2 A$~GeV bestrahlt wurde. Es konnten klare Signale f{"{u}}r $Lambda$, $^3_{Lambda}$H, $^4_{Lambda}$H in deren jeweiligen invarianten Massenverteilungen aus Mesonenzerfall beobachtet werden.rnrnIn dieser Arbeit wird eine unabh{"{a}}ngige Datenauswertung vorgelegt, die eine Verifizierung fr"{u}herer Ergebnisse der HypHI Kollaboration zum Ziel hatte. Zu diesem Zweck wurde eine neue Track-Rekonstruktion, basierend auf einem Kalman-Filter-Ansatz, und zwei unterschiedliche Algorithmen zur Rekonstruktion sekund"{a}rer Vertices entwickelt.rn%-Rekonstruktionsalgorithmen .rnrnDie invarianten Massen des $Lambda$-Hyperon und der $^3_{Lambda}$H- und $^4_{Lambda}$H-Hyperkerne wurden mit $1109.6 pm 0.4$, $2981.0 pm 0.3$ und $3898.1 pm 0.7$~MeV$/c^2$ und statistischen Signifikanzen von $9.8sigma$, $12.8sigma$ beziehungsweise $7.3sigma$ bestimmt. Die in dieser Arbeit erhaltenen Ergebnisse stimmen mit der fr{"{u}}heren Auswertung {"{u}}berein.rnrnDas Ausbeutenverh{"{a}}ltnis der beiden Hyperkerne wurde als $N(^3_{Lambda}$H)/$N(^4_{Lambda}$H)$ sim 3$ bestimmt. Das deutet darauf hin, dass der Produktionsmechanismus f{"{u}}r Hyperkerne in Schwerionen-induzierten Reaktionen im Projektil-Rapidit{"{a}}tsbereich nicht allein durch einen Koaleszenzmechanismus beschrieben werden kann, sondern dass auch sekund{"{a}}re Pion-/Kaon-induzierte Reaktionen und Fermi-Aufbruch involviert sind.rn

Neoadjuvant interstitial high-dose-rate (HDR) brachytherapy combined with systemic chemotherapy in patients with breast cancer

BACKGROUND AND PURPOSE: This is the first study investigating neoadjuvant interstitial high-dose-rate (HDR) brachytherapy combined with chemotherapy in patients with breast cancer. The goal was to evaluate the type of surgical treatment, histopathologic response, side effects, local control, and survival. PATIENTS AND METHODS: 53 patients, who could not be treated with breast-conserving surgery due to initial tumor size (36/53) or due to an unfavorable breast-tumor ratio (17/53), were analyzed retrospectively. All but one were in an intermediate/high-risk group (St. Gallen criteria). The patients received a neoadjuvant protocol consisting of systemic chemotherapy combined with fractionated HDR brachytherapy (2 x 5 Gy/day, total dose 30 Gy). In cases, where breast-conserving surgery was performed, patients received additional external-beam radiotherapy (EBRT, 1.8 Gy/day, total dose 50.4 Gy). In patients, who underwent mastectomy but showed an initial tumor size of T3/T4 and/or more than three infiltrated lymph nodes, EBRT was also performed. RESULTS: In 30/53 patients (56.6%) breast-conserving surgery could be performed. The overall histopathologic response rate was 96.2% with a complete remission in 28.3% of patients. 49/53 patients were evaluable for follow-up. After a median of 58 months (45-72 months), one patient showed a mild fibrosis of the breast tissue, three patients had mild to moderate lymphatic edema of the arm. 6/49 (12.2%) patients died of distant metastases, 4/49 (8.2%) were alive with disease, and 39/49 (79.6%) were free from disease. Local recurrence was observed in only one case (2%) 40 months after primary therapy. After mastectomy, this patient is currently free from disease. CONCLUSION: The combination of interstitial HDR brachytherapy and chemotherapy is a well-tolerated and effective neoadjuvant treatment in patients with breast cancer. Compared to EBRT, treatment time is short. Postoperative EBRT of the whole breast -- if necessary -- is still possible after neoadjuvant brachytherapy. Even though the number of patients does not permit definite conclusions, the results are promising regarding survival and the very low rate of local recurrences.

Age dependency of intrarenal resistance index (RI) in healthy adults and patients with fatty liver disease

BACKGROUND: Our aim was to investigate the influence of age and gender on intrarenal resistance index (RI) measurements in 78 healthy subjects (46 males, 32 females; group 1) and 35 subjects (group 2) with fatty liver disease (28 males and 7 females). SUBJECTS AND METHODS: First, each subject underwent a conventional abdominal ultrasound examination. Then, intrarenal RI values were determined from three distinct interlobar and cortical arteries respectively on both kidneys. The correlation of intrarenal RI with age and gender as a variable was statistically evaluated by linear regression. RESULTS: In group 1, the variables gender, kidney region and comparison of right versus left kidney had no significant effect on intrarenal RI (p>0.05). The variable age, on the other hand, showed a significant positive correlation on all four defined measuring points (p<0.01) with linear correlation coefficients of r = 0.26 (left kidney, central) to r = 0.37 (right kidney, cortical). Therefore normal RI values at ages 25, 45, 65 years could be defined as 0.59, 0.61 and 0.63, respectively. Age dependency can thus be expressed as a function with the formula y = 0.565 + 0.001.x. Patients with fatty liver disease showed age dependency on renal RI (p<0.01) as well. CONCLUSION: In accordance with other studies, the influence of age on intrarenal RI measurement is significant in healthy subjects. Intrarenal RI values from subjects with a fatty liver disease showed age dependency as well. Therefore it is necessary to consider the age of the examined person to interpret RI values correctly.

Association of the composite IL-1 genotype with peri-implantitis: a systematic review

OBJECTIVE: Cytokine gene polymorphisms may modulate the host response to the bacterial challenge and influence susceptibility to peri-implantitis. OBJECTIVE: To systematically review the evidence of an association between the interleukin-1 (IL-1) composite genotype, i.e. presence of the allele 2 in the gene clusters IL-1A (-889) and in IL-1B (+3953), and peri-implantitis. MATERIAL AND METHODS: An electronic search in the National Library of Medicine-computerized bibliographic database MEDLINE and a manual search were performed. The search was conducted for longitudinal clinical trials comparing progression of peri-implantitis in IL-1 genotype positive (carrying allele 2) with IL-1 genotype negative (not carrying allele 2) subjects. Selection of publications, extraction of data and validity assessment were made independently by two reviewers. RESULTS: The search provided 44 titles of which two longitudinal publications were included. CONCLUSION: Based on the findings from this study, there is not enough evidence to support or refute an association between the IL-1 genotype status and peri-implantitis. Systematic genetic testing for the assessment of the risk of peri-implantitis cannot be recommended as a standard of care at this time.

Performance evaluation and characterization of symmetric capacitors with carbon black, and asymmetric capacitors using a carbon foam supported nickel electrode

This thesis evaluates a novel asymmetric capacitor incorporating a carbon foam supported nickel hydroxide positive electrode and a carbon black negative electrode. A series of symmetric capacitors were prepared to characterize the carbon black (CB) negative electrode. The influence of the binder, PTFE, content on the cell properties was evaluated. X-ray diffraction characterization of the nickel electrode during cycling is also presented. The 3 wt% and 5 wt% PTFE/CB symmetric cells were examined using cyclic voltammetry (CV) and constant current charge/discharge measurements. As compared with symmetric cells containing more PTFE, the 3 wt% cell has the highest average specific capacitance, energy density and power density over 300 cycles, 121.8 F/g, 6.44 Wh/kg, and 604.1 W/kg, respectively. Over the 3 to 10 wt% PTFE/CB range, the 3 wt% sample exhibited the lowest effective resistance and the highest BET surface area. Three asymmetric cells (3 wt% PTFE/CB negative electrode and a nickel positive) were fabricated; cycle life was examined at 3 current densities. The highest average energy and power densities over 1000 cycles were 20 Wh/kg (21 mA/cm2) and 715 W/kg (31 mA/cm2), respectively. The longest cycle life was 11,505 cycles (at 8 mA/cm2), with an average efficiency of 79% and an average energy density of 14 Wh/kg. The XRD results demonstrate that the cathodically deposited nickel electrode is a typical α-Ni(OH)2 with the R3m structure (ABBCCA stacking); the charged electrodes are 3γ-NiOOH with the same stacking as the α-type; the discharged electrodes (including as-formed electrode) are aged to β’-Ni(OH)2 (a disordered β) with the P3m structure (ABAB stacking). A 3γ remnant was observed.

Fixed block configuration GDDs with block size 6 and (3, r)-regular graphs

Chapter 1 is used to introduce the basic tools and mechanics used within this thesis. Most of the definitions used in the thesis will be defined, and we provide a basic survey of topics in graph theory and design theory pertinent to the topics studied in this thesis. In Chapter 2, we are concerned with the study of fixed block configuration group divisible designs, GDD(n; m; k; λ1; λ2). We study those GDDs in which each block has configuration (s; t), that is, GDDs in which each block has exactly s points from one of the two groups and t points from the other. Chapter 2 begins with an overview of previous results and constructions for small group size and block sizes 3, 4 and 5. Chapter 2 is largely devoted to presenting constructions and results about GDDs with two groups and block size 6. We show the necessary conditions are sufficient for the existence of GDD(n, 2, 6; λ1, λ2) with fixed block configuration (3; 3). For configuration (1; 5), we give minimal or nearminimal index constructions for all group sizes n ≥ 5 except n = 10, 15, 160, or 190. For configuration (2, 4), we provide constructions for several families ofGDD(n, 2, 6; λ1, λ2)s. Chapter 3 addresses characterizing (3, r)-regular graphs. We begin with providing previous results on the well studied class of (2, r)-regular graphs and some results on the structure of large (t; r)-regular graphs. In Chapter 3, we completely characterize all (3, 1)-regular and (3, 2)-regular graphs, as well has sharpen existing bounds on the order of large (3, r)- regular graphs of a certain form for r ≥ 3. Finally, the appendix gives computational data resulting from Sage and C programs used to generate (3, 3)-regular graphs on less than 10 vertices.