This thesis explores structure as a visual and literal framework for a building. The relationships or connections of discreet pieces to the framework, whether on the scale of a handrail or the brick cylinder is the basic structure of the project. The structural grid establishes an order. It defines the boundaries of the house. The enclosure and spaces within the grid of columns and beams can then respond to other temporal considerations. / Master of Architecture

We may rattle our tongues and cold we may rattle our bones; It is our actions that will haunt them. / Master of Architecture

In the act of building, man places himself between earth and sky. Where a wall is raised, a place becomes divided. Architecture occurs. One wall in one place begins to define three physical realities. The form and matter of a wall exist as one thing. Each side of the wall exists separately and face opposing parts. The wall is a barrier, yet acts as an architectural element that joins the two sides. / Master of Architecture

The Becker Hudsons, a young family with two children, have commissioned the design of a house In Aroostook County, Maine. The program requirements include the use of wood for both heating and cooking, an area for the children to play within sight of the primary living areas, a separate bedroom for each child, and a small sanctum. The Architect will be the builder. / Master of Architecture

Master of Architecture

There is limited anthropological research on inclusive play and universally designed playgrounds and this study aims to make some contribution in this field. This was a qualitative research study guided by anthropological theory and methods, conducted for For the Love of the Lake (FTLOTL) Foundation. FTLOTL is a non-profit organization located in Dallas, Texas, dedicated to White Rock Lake Park's maintenance. In 2014, FTLOTL became of the view that the park's current playgrounds lacked accessibility for differently-abled children. Therefore, FTLOTL decided to undertake a renovation project of Flag Pole Hill playground to incorporate inclusiveness and diversity in the playground design. The overarching objective of this exploratory, ethnographic needs assessment was to provide insights for an inclusive playground using universal design for families with special needs children. Fourteen parents, each with at least one child having physical, social, or intellectual disabilities in the Dallas/Fort Worth (DFW) Texas metroplex were interviewed. The interviews were semi structured, each lasting for about an hour and were digitally recorded. Later these audio recordings were transcribed verbatim and then coded using Dedoose. The coded data was synthesized into coherent themes and sub-themes and finally organized into formal research findings. Observations were made of existing universally designed as well as typical playgrounds in this region. All parents interviewed supported the playground initiative and gave suggestions for physical accessibility along with social inclusion. They expressed their frustrations and apprehensions about the usability of current playgrounds. They also shared their preferences for facilities, features, and equipment to support their children's physical and social needs as well as their own. There was a unanimous agreement that a universally designed playground would have recreational, therapeutic and emotional benefits for participants and would improve the quality of their family lives and build a more closely-knit community.

A produção comercial de peixes carnívoros exige o uso de um conjunto complexo de práticas de manejo da produção e alimentação, à redução do impacto ambiental dos alimentos e à minimização do emprego de fontes protéicas de origem animal nas formulações das dietas. O objetivo do presente estudo foi investigar o uso de atrativos alimentares em dietas formuladas exclusivamente à base de proteína de origem vegetal (PV), e seus efeitos no desempenho, composição corporal e digestibilidade das dietas pelo carnívoro "black bass", Micropterus salmoides, condicionados a aceitar ração seca. Novecentos juvenis (26,54 ± 1,53 g) foram estocados em 60 aquários de polietileno de 90 L (15 peixes/aquário), em delineamento experimental totalmente ao acaso (n=3), e alimentados ad libitum em duas refeições diárias (07h00m e 17h00m), durante 13 dias, com uma dieta basal (100% PV) contendo seis níveis de proteína solúvel de peixe - PSP (0,5, 1,0, 1,5, 2,0, 2,5 e 3,0%); Fisharom ® - FA (0,02, 0,04, 0,06, 0,08, 0,10 e 0,12%); silagem de peixe - SP (1,0, 2,0, 3,0, 4,0, 5,0 e 6,0%); um controle positivo (10% de farinha de peixe) e um controle negativo (dieta basal sem atrativos). Os peixes alimentados com a dieta contendo FA 0,02% apresentaram melhor taxa de crescimento, ganho de peso e conversão alimentar, mas não apresentaram diferenças dos demais tratamentos (P>0,05). Os peixes alimentados com dietas contendo SP como atrativo apresentaram os piores resultados de desempenho. Em uma segunda etapa, foi avaliado o desempenho e a composição corporal de 560 juvenis (3,06 ± 0,20 g) estocados em gaiolas de 60 L, dentro de caixas de polietileno de 1.000 L, instaladas em laboratório com um sistema fechado de recirculação de água com temperatura (27 o C ± 1,07 o C) e fotoperíodo (14L:10E) controlados, em um delineamento experimental totalmente ao acaso (n=4), e alimentados ad libitum em duas refeições diárias (07h00m e 17h00m), durante 43 dias, com 7 dietas isonitrogenadas (40% de PB) e isocalóricas (3.500 kcal/kg), contendo níveis decrescentes de proteína de origem vegetal: 100PV:00PA; 100PV + 0,02% Fisharon ® ; 80PV:20PA; 60PV:40PA; 40PV:60PA; 50PV:50PA (sem farinha de peixe); e uma dieta controle (ração comercial). A inclusão de farinha de peixe e farinha de penas foi limitada em 7%; a inclusão de farinha de vísceras e farinha de carne em 15%. DL-metionina (98%) e L-lisina (80%) foram adicionadas automaticamente através de matriz de aplicativo de formulação de ração. Em uma terceira etapa, foi avaliada a digestibilidade das rações utilizadas no experimento anterior. Para tanto, 1.960 juvenis (14,0 ± 1,0 cm) foram confinados em gaiolas de polipropileno e alimentados durante 40 dias, no período diurno, com as sete dietas do experimento anterior acrescidas de 0,5% de óxido de cromio. No período noturno as gaiolas eram transferidas para aquários cilíndrico-cônicos de 200 L, onde as fezes eram coletadas por sedimentação em recipiente refrigerado. O farelo de soja pode ser utilizado como substituto parcial de fontes protéicas e origem animal em rações formuladas para o "black bass"; a farinha de vísceras pode ser considerada uma boa opção como fonte protéica de origem animal em rações. Os melhores resultados de desempenho foram relacionados aos tratamentos controle e 50PV:50PA. A necessidade do uso da farinha de peixe na formulação de dietas para espécies carnívoras é no mínimo questionável e a determinação da digestibilidade das rações, visando maior precisão em formulações de custo mínimo para peixes carnívoros, deve ser prática corrente na indústria da alimentação de peixes. / Commercial farming of carnivorous fish demands the use of a complex group of practices of production and feeding management, the reduction of the environmental impact of the feeds and the minimization of the use of animal protein sources in the diets. The present study investigated the use of feed stimulants in diets formulated exclusively out of plant protein, and their effects in growth performance, body composition and digestibility of the feeds for the carnivore largemouth bass, Micropterus salmoides, conditioned to accept dry feed. Nine hundred juvenile largemouth bass (26.54 ± 1.53 g) were stocked in 60, 90-L polyethylene aquaria (15 fish/aquarium), in a totally randomized experimental design (n=3). Fish were fed ad libitum two daily meals (0700 and 1700), for 13 days, with a basal diet (100% plant protein) containing increasing levels of fish soluble protein - FSP (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0%); Fisharom TM - FA (0.02, 0.04, 0.06, 0.08, 0.10 and 0.12%); fish silage - FS (1.0, 2.0, 3.0, 4.0, 5.0 and 6.0%); a positive control (10% of fish meal) and a negative control (basal diet without stimulants). Fish fed the diet containing 0.02%FA presented better growth rate, weight gain and feed conversion rate, but did not differ from the other treatments (P>0,05). Fish fed diets containing FS as stimulant presented the poorest performance. Next, the effect of different levels of dietary plant protein in the performance and body composition of the species was evaluated. Five hundred and sixty juvenile largemouth bass (3.06 ± 0.20 g) were stocked in 60-L cages, inside 1,000-L polyethylene tanks, installed at a laboratory with closed water-recirculating system and controled temperature (27 o C ± 1.07 o C) and photoperiod (14L:10D). Fish were fed ad libitum two daily meals (0700 and 1700), for 43 days, with 7 isonitrogenous (40% of PB) and isoenergetic (3,500 kcal/kg) diets, containing decreasing levels of plant protein: 100PP:00AP; 100PP + 0.02% Fisharom®; 80PP:20AP; 60PP:40AP; 40PP:60AP; 50PP:50AP (without fish meal); and a control diet (commercial feed). Inclusion of fish meal and feathers meal was limited to 7%; the inclusion of poultry by-product meal and meat and bone meal to 15%. DL methionine (98%) and L-lysine (80%) were added automatically through feed formulation software matrix. Trial was set up in a totally randomized experimental design (n=4). Finally, digestibility of the diets used in the experiment 2 was studied. One thousand, nine hundred and eighty juvenile largemouth bass (14.0 ± 1.0 cm) conditioned to accept artificial, dry feed were confined in polypropilene cages and fed, for 40 days, in day time, with the seven experimental diets added of 0.5% of cromic oxide. In the night, cages were transferred to cylindrical-conical bottomed, 200-L aquaria, where feces were collected by sedimentation into refrigerated containers. Data were submitted to the ANOVA and Tukey’s test of comparison of means through statistical software package SAS (P=0.05). Soybean meal can be used as partial substitute of animal protein in diets for largemouth bass; the poultry by-product meal shows as a good option as animal protein source in these rations. Best performances were related to the control treatments and 50PP:50AP; the need for the use of fishmeal in the formulation of diets for carnivorous species is, at least, questionable. Results of the digestibility trials demonstrated the importance of determining the digestibility of the rations, if precision in the formulation of least-cost feeds for carnivorous fish is the ultimate goal.

A produção comercial de peixes carnívoros exige o uso de um conjunto complexo de práticas de manejo da produção e alimentação, à redução do impacto ambiental dos alimentos e à minimização do emprego de fontes protéicas de origem animal nas formulações das dietas. O objetivo do presente estudo foi investigar o uso de atrativos alimentares em dietas formuladas exclusivamente à base de proteína de origem vegetal (PV), e seus efeitos no desempenho, composição corporal e digestibilidade das dietas pelo carnívoro “black bass”, Micropterus salmoides, condicionados a aceitar ração seca. Novecentos juvenis (26,54 ± 1,53 g) foram estocados em 60 aquários de polietileno de 90 L (15 peixes/aquário), em delineamento experimental totalmente ao acaso (n=3), e alimentados ad libitum em duas refeições diárias (07h00m e 17h00m), durante 13 dias, com uma dieta basal (100% PV) contendo seis níveis de proteína solúvel de peixe – PSP (0,5, 1,0, 1,5, 2,0, 2,5 e 3,0%); Fisharom ® – FA (0,02, 0,04, 0,06, 0,08, 0,10 e 0,12%); silagem de peixe – SP (1,0, 2,0, 3,0, 4,0, 5,0 e 6,0%); um controle positivo (10% de farinha de peixe) e um controle negativo (dieta basal sem atrativos). Os peixes alimentados com a dieta contendo FA 0,02% apresentaram melhor taxa de crescimento, ganho de peso e conversão alimentar, mas não apresentaram diferenças dos demais tratamentos (P>0,05). Os peixes alimentados com dietas contendo SP como atrativo apresentaram os piores resultados de desempenho. Em uma segunda etapa, foi avaliado o desempenho e a composição corporal de 560 juvenis (3,06 ± 0,20 g) estocados em gaiolas de 60 L, dentro de caixas de polietileno de 1.000 L, instaladas em laboratório com um sistema fechado de recirculação de água com temperatura (27 o C ± 1,07 o C) e fotoperíodo (14L:10E) controlados, em um delineamento experimental totalmente ao acaso (n=4), e alimentados ad libitum em duas refeições diárias (07h00m e 17h00m), durante 43 dias, com 7 dietas isonitrogenadas (40% de PB) e isocalóricas (3.500 kcal/kg), contendo níveis decrescentes de proteína de origem vegetal: 100PV:00PA; 100PV + 0,02% Fisharon ® ; 80PV:20PA; 60PV:40PA; 40PV:60PA; 50PV:50PA (sem farinha de peixe); e uma dieta controle (ração comercial). A inclusão de farinha de peixe e farinha de penas foi limitada em 7%; a inclusão de farinha de vísceras e farinha de carne em 15%. DL-metionina (98%) e L-lisina (80%) foram adicionadas automaticamente através de matriz de aplicativo de formulação de ração. Em uma terceira etapa, foi avaliada a digestibilidade das rações utilizadas no experimento anterior. Para tanto, 1.960 juvenis (14,0 ± 1,0 cm) foram confinados em gaiolas de polipropileno e alimentados durante 40 dias, no período diurno, com as sete dietas do experimento anterior acrescidas de 0,5% de óxido de cromio. No período noturno as gaiolas eram transferidas para aquários cilíndrico-cônicos de 200 L, onde as fezes eram coletadas por sedimentação em recipiente refrigerado. O farelo de soja pode ser utilizado como substituto parcial de fontes protéicas e origem animal em rações formuladas para o “black bass”; a farinha de vísceras pode ser considerada uma boa opção como fonte protéica de origem animal em rações. Os melhores resultados de desempenho foram relacionados aos tratamentos controle e 50PV:50PA. A necessidade do uso da farinha de peixe na formulação de dietas para espécies carnívoras é no mínimo questionável e a determinação da digestibilidade das rações, visando maior precisão em formulações de custo mínimo para peixes carnívoros, deve ser prática corrente na indústria da alimentação de peixes. / Commercial farming of carnivorous fish demands the use of a complex group of practices of production and feeding management, the reduction of the environmental impact of the feeds and the minimization of the use of animal protein sources in the diets. The present study investigated the use of feed stimulants in diets formulated exclusively out of plant protein, and their effects in growth performance, body composition and digestibility of the feeds for the carnivore largemouth bass, Micropterus salmoides, conditioned to accept dry feed. Nine hundred juvenile largemouth bass (26.54 ± 1.53 g) were stocked in 60, 90-L polyethylene aquaria (15 fish/aquarium), in a totally randomized experimental design (n=3). Fish were fed ad libitum two daily meals (0700 and 1700), for 13 days, with a basal diet (100% plant protein) containing increasing levels of fish soluble protein – FSP (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0%); Fisharom TM – FA (0.02, 0.04, 0.06, 0.08, 0.10 and 0.12%); fish silage – FS (1.0, 2.0, 3.0, 4.0, 5.0 and 6.0%); a positive control (10% of fish meal) and a negative control (basal diet without stimulants). Fish fed the diet containing 0.02%FA presented better growth rate, weight gain and feed conversion rate, but did not differ from the other treatments (P>0,05). Fish fed diets containing FS as stimulant presented the poorest performance. Next, the effect of different levels of dietary plant protein in the performance and body composition of the species was evaluated. Five hundred and sixty juvenile largemouth bass (3.06 ± 0.20 g) were stocked in 60-L cages, inside 1,000-L polyethylene tanks, installed at a laboratory with closed water-recirculating system and controled temperature (27 o C ± 1.07 o C) and photoperiod (14L:10D). Fish were fed ad libitum two daily meals (0700 and 1700), for 43 days, with 7 isonitrogenous (40% of PB) and isoenergetic (3,500 kcal/kg) diets, containing decreasing levels of plant protein: 100PP:00AP; 100PP + 0.02% Fisharom®; 80PP:20AP; 60PP:40AP; 40PP:60AP; 50PP:50AP (without fish meal); and a control diet (commercial feed). Inclusion of fish meal and feathers meal was limited to 7%; the inclusion of poultry by-product meal and meat and bone meal to 15%. DL methionine (98%) and L-lysine (80%) were added automatically through feed formulation software matrix. Trial was set up in a totally randomized experimental design (n=4). Finally, digestibility of the diets used in the experiment 2 was studied. One thousand, nine hundred and eighty juvenile largemouth bass (14.0 ± 1.0 cm) conditioned to accept artificial, dry feed were confined in polypropilene cages and fed, for 40 days, in day time, with the seven experimental diets added of 0.5% of cromic oxide. In the night, cages were transferred to cylindrical-conical bottomed, 200-L aquaria, where feces were collected by sedimentation into refrigerated containers. Data were submitted to the ANOVA and Tukey’s test of comparison of means through statistical software package SAS (P=0.05). Soybean meal can be used as partial substitute of animal protein in diets for largemouth bass; the poultry by-product meal shows as a good option as animal protein source in these rations. Best performances were related to the control treatments and 50PP:50AP; the need for the use of fishmeal in the formulation of diets for carnivorous species is, at least, questionable. Results of the digestibility trials demonstrated the importance of determining the digestibility of the rations, if precision in the formulation of least-cost feeds for carnivorous fish is the ultimate goal.

The study of synthetic peptides aid in improving our current understanding of the fundamental principles for the de novo design of functional proteins. The investigation of designed peptides has been instrumental in providing answers to many questions ranging from the conformational preferences of amino acids to the compact folded structures and also in developing tools for understanding the growth and formation of the protein secondary structures (helices, sheets and turns). In addition, the self-assembly of peptides through non-covalent interactions is also an emerging area of growing interest. The design of peptides which can mimic the protein secondary structures relies on the use of stereochemically constrained amino acid residues at select positions in the linear peptide sequences, leading to the construction of protein secondary structural modules like helices, hairpins and turns. The use of non-coded amino acid residues with strict preferences for adopting particular conformations in the conformational space becomes the most crucial step in peptide design strategies. In addition the crystallographic characterization and analysis of the sequences provides the necessary optimization of the design strategies. The crystallographic characterization of designed peptides provides a definitive and conclusive proof of the success of a design strategy. Furthermore, the X-ray structures provide an atomic view of the interactions, both strong and weak, which govern the growth of the crystal. The information on the geometric parameters and stereochemical properties of a series of peptides, through a systematic study, provides the necessary basis for further scientific investigation, like the molecular dynamics and can also aid in improving the force field parameters meant for carrying out molecular simulations. This can be further complemented by constructing biologically active peptide sequences. The focus of this thesis is to characterize crystallographically the conformational and structural aspects of peptide nanotubes and encapsulated water wires and the β-hairpin peptide models of β-sheets. The systematic study of a series of pentapeptide and octapeptide sequences, containing Aib and D-amino acid residues incorporated at strategic positions, establish the conformation and structural properties of designed peptides as mimics of protein secondary structures and hydrophobic tubular peptide channels and close-packed forms. The structures reported in this thesis are given below: 1 Boc-DPro-Aib-Leu-Aib-Val-OMe (DPUL5) C30H53N5O8 2 Boc-DPro-Aib-Val-Aib-Val-OMe (DPUV5a) C29H51N5O8 .(0.5) H2O 3 Boc-DPro-Aib-Val-Aib-Val-OMe (DPUV5b) C27H51N5O8 .(0.17) H2O 4 Boc-DPro-Aib-Ala-Aib-Val-OMe (DPUA5) C27H47N5O8 5 Boc-DPro-Aib-Phe-Aib-Val-OMe (DPUF5) C33H48N5O8 6 Boc-Pro-Aib-DLeu-Aib-DVal-OMe (PUDL5) C30H53N5O8 7 Boc-Pro-Aib-DVal-Aib-DVal-OMe (PUDV5a) C27H51N5O8 .(0.17) H2O 8 Boc-Pro-Aib-DVal-Aib-DVal-OMe (PUDV5b) C27H51N5O8 . 2H2O 9 Boc-Pro-Aib-DAla-Aib-DVal-OMe (PUDA5) C27H47N5O8 10 Boc-Pro-Aib-DPhe-Aib-DVal-OMe (PUDF5) C33H48N5O8 11 Ac-Phe-Pro-Trp-OMe (FPW) C28H32N4O5.(0.33)H2O 12 Boc-Leu-Phe-Val-DPro-Pro-Leu-Phe-Val-OMe (DPLP8) C56H84N8O1 1 .(0.5) H2O 13 Boc-Leu-Phe-Val-DPro-Pro-Leu-Phe-Val-OMe (YDPP8) C56H83N8O12 .(1.5) H2O 14 Boc-Leu-Val-Val-DPro-ψPro-Leu-Val-Val-OMe (PSIP8) C56H84N8O11S1 .(1.5) H2O 15 Boc-Leu-Phe-Val-DPro-Pro-Leu-Phe-Val-OMe (DPPV8) C48H84N8O11 16 Boc-Leu-Phe-Val-DPro-Aib-Leu-Phe-Val-OMe (DPUF8) C57H88N8O11.(1.5) H2O 17 Piv-Pro-ψH,CH3Pro-NHMe (PSPL3) C22H37N3O5S1 18 Boc-Leu-Val-Val-Aib-DPro-Leu-Val-Val-OMe (UDPV8) C47H84N8O11.2(C3H7NO) 19 Boc-Leu-Phe-Val-DPro-Ala-Leu-Phe-Val-OMe (BH1P8) C54H78N8O11.H2O 20 Boc-Leu-Phe-Val-DPro-Aib-Leu-Phe-Val-OMe (DPUFP8) C55H84N8O11. (0.5) H2O 21 Boc-Leu-Phe-Val-DPro-Pro-Leu-Phe-Val-OMe (YDPPP8) C56H83N8O12. (1.5) H2O The crystal structure determination of the peptides presented in this thesis provides a wealth of information on the folding patterns of the sequences, in addition to the characterization of many structural and geometric properties. In particular, the study sheds light on the growth and formation of peptide nanotubes and the structure of encapsulated water wires, and also the structural details of Type I′ and Type II′β-turn nucleated hairpins. The study provides the backbone and side chain conformational parameters of the sequences, highlighting the varied conformational excursions possible in the peptide molecules. The thesis is divided into 6 chapters and one appendix. Chapter 1 gives a general introduction to the stereochemistry of the polypeptide chain, description of backbone torsion angles of α-amino acid residues and the major secondary structures of α-peptides, namely α-helix, β-sheet and β-turns. The basic structural features of helices and sheets are given. A brief introduction to polymorphism and weak interactions is also presented, followed by a discussion on X-ray diffraction and solution to the phase problem. Chapter 2 is divided into two parts. PART 1 describes the crystal structures of a series of eight related enantiomeric peptide sequences (Raghavender et al., 2009; Raghavender et al., 2010). The crystal structures of four sequences with the general formula Boc-DPro-Aib-Xxx-Aib-Val-OMe (Xxx = Ala/Val/Leu/Phe) and the enantiomeric sequences provided a set of crystal structures withdifferent packing arrangements. The structure of the peptide with Xxx = Leu revealed a nanotube formation with the Leu lining the inner walls of channel. The channels were found to be empty. The sequence with Xxx = Val revealed a solvent-filled water channel.Investigation of the water wire structures on the diffraction data collected on the same crystal over a period of time revealed the existence of two different kinds of water wires in thechannels. Comparison with the peptide tubular structures available in the literature and the water structure inside the aquaporin channels are contrasted. Close-packed structures are observed in the case of Xxx=Ala and Phe. The backbone conformations are essentially identical. Enantiomeric sequences also revealed similar structures. Polymorphic forms were observed in the case of DVal(3) containing sequence. One form is observed to have water-filled channels forming a nanotube, as opposed to the close-packed structure in the polymorphic form. Crystal parameters DPUL5: C30H53N5O8; P65; a = b = 24.3673 (9) Å, c = 10.6844 (13) Å; α = β = 90°, γ = 120°; Z = 6; R = 0.0671, wR2 = 0.1446. DPUV5a: C29H51N5O8 .(0.5) H2O; P65; a = b = 24.2920 (13) Å, c = 10.4838 (11) Å; α = β = 90°, γ = 120°; Z = 6; R = 0.0554, wR2 = 0.1546. DPUV5b: C29H51N5O8 .(0.17) H2O; P65; a = b = 24.3161 (3) Å, c = 10.1805 (1) Å; α = β = 90°, γ = 120°; Z = 6; R = 0.0617, wR2 = 0.1844. DPUA5: C27H47N5O8; P212121; a = 12.2403 (8), b = 15.7531 (11) Å, c = 16.6894 (11) Å; Z =4; R = 0.0439, wR2 = 0.1249. DPUF5: C33H48N5O8; P212121; a = 10.3268 (8), b = 18.7549 (15) Å, c = 18.9682 (16) Å; Z = 4; R = 0.0472, wR2 = 0.1325. PUDL5: C30H53N5O8; P61; a = b = 24.4102 (8) Å, c = 10.6627 (7) Å; α = β = 90°, γ = 120°; Z = 6; R = 0.0543, wR2 = 0.1495. PUDV5a: C29H51N5O8 .(0.17)H2O; P61; a = b = 24.3645 (14) Å, c = 10.4875 (14) Å; α = β = 90°, γ = 120°; Z = 6; R = 0.0745, wR2 = 0.1810. PUDV5b: C29H51N5O8. 2H2O; C2; a = 20.7278 (35), b = 9.1079 (15) Å, c = 19.5728 (33) Å; α = γ = 90°, β = 94.207°; Z = 6; R = 0.0659, wR2 = 0.1755. PUDA5: C27H47N5O8; P212121; a = 12.2528 (12), b = 15.7498 (16) Å, c = 16.6866 (16) Å; Z = 4; R = 0.0473, wR2 = 0.1278. PUDF5: C33H48N5O8; P212121; a = 10.3354 (8), b = 18.7733 (10) Å, c = 18.9820 (10) Å; Z = 4; R = 0.0510, wR2 = 0.1526. PART 2 describes the crystallographic characterization of the tubular structure in a tripeptide Ac-Phe-Pro-Trp-OMe (FPW) sequence. The arrangement of the single-file water moleculesin the peptide nanotubes of FPW could be established by X-ray diffraction. In addition, the energetically favoured arrangement of the water wire inside the peptide channels could be modeled by understanding the construction of the peptide nanotube. In particular, the helicalmacrodipole of the peptide nanotube and the water wire dipoles prefer an antiparallel arrangement inside the peptide channels as opposed to parallel arrangements, is established by the classical dipole-dipole interaction energy calculation. In addition, the growth of thenanotubes and the arrangement of the water wires inside the channels could be correlated to the macroscopic dimensions of the crystal by the indexing of the crystal faces and contrasted with the structure of DPUV5. Crystal parameters FPW: C28H32N4O5.(0.33)H2O; P65; a = b = 21.5674 (3) Å, c = 10.1035 (2) Å; α = β = 90°, γ = 120 °; Z = 6; R = 0.0786, wR2 = 0.1771 Chapter 3 provides the crystal structures of five octapeptide β-hairpin forming sequences and a tripeptide containing a modified amino acid, with modification in the side chain (pseudo-proline, ψH,CH3Pro). The parent peptide, Boc-Leu-Phe-Val-DPro-Pro-Leu-Phe-Val-OMe (DPLP8), was observed to form a strong Type II′β-turn at the DPro-Pro segment, and the strand segments adopting a β-sheet conformation. Two molecules were observed in the asymmetric unit, inclined to each other at approximately 70°. Modification in the strand sequence Phe(2) to Tyr(2) also resulted in a hairpin with identical conformation and similar packing arrangement. The difference was in the solvent content. In both the cases the molecules were packed orthogonal with respect to each other, resulting in the formation of ribbon-like structures in three dimensions. The replacement of Phe(2) and Phe(7) with Valine residues, with the retention of DPro-Pro β-turn segment, results in an entiely different packing arrangement (parallel). Modification of Pro(5) residue of the turn segment to Aib(5) and ψPro, also results in the molecules packing orthogonally to each other. The tripeptide with a modified form of ψPro, namely ψH,CH3Pro, resulted in a folded structure with a Type VIa β-turn, with the amide bond between the Pro-ψH,CH3Pro segment adopting a cis configuration (Kantharaju et al., 2009). Crystal parameters DPLP8: C56H84N8O11 .(0.5) H2O; P21; a = 14.4028 (8), b = 18.9623 (11) Å, c = 25.4903 (17) Å, β = 105.674 ° (4); Z = 4; R = 0.0959, wR2 = 0.2251. YDPP8: C56H84N8O12 .(1.5) H2O; P212121; a = 14.4028 (8), b = 18.9623 (11) Å, c = 25.4903 (17) Å, Z = 8; R = 0.0989, wR2 = 0.2064. PSIP8: C57H86N8O11S1.(1.5) H2O; C2; a = 34.6080 (2), b = 15.3179 (10) Å, c = 25.6025 (15) Å, β = 103.593 ° (3); Z = 4; R = 0.0931, wR2 = 0.2259. DPPV8: C48H84N8O11; P1; a = 9.922 (3), b = 11.229 (4) Å, c = 26.423 (9) Å, α = 87.146 (6), β = 89.440° (6), γ = 73.282 (7); Z = 2; R = 0.1058, wR2 = 0.2354. DPUF8: C57H88N8O11 .(1.5) H2O; P21; a = 18.410 (2), b = 23.220 (3) Å, c = 19.240 (3) Å, β = 118.036 ° (4); Z = 4; R = 0.1012, wR2 = 0.2061. PSPL3: C22H37N3O5S1; P31; a = b = 14.6323 (22), c = 10.4359 (22) Å, α = β = 90°, γ = 120°; Z = 3; R = 0.0597, wR2 = 0.1590. Chapter 4 describes the crystal structure and molecular conformation of Type I′β-turn nucleated hairpin. The incorporation of Aib-DPro segment in the middle of Leu-Val-Val strands in the peptide sequence Boc-Leu-Val-Val-Aib-DPro-Leu-Val-Val-OMe results in an obligatory Type I′ turn containing hairpin. The molecular conformation and the packing arrangement of the molecules in the crystal are contrasted with the only Type I′β-hairpin reported in the literature and with a sequence where the turn residues are flipped and strand residues replaced with Phe(2) and Phe(7). Crystal parameters UDPV8: C47H84N8O11.2(C3H7NO); P21; a = 11.0623 (53), b = 18.7635 (89) Å, c = 16.6426 (80) Å, β = 102.369 (8); Z = 2; R = 0.0947, wR2 = 0.1730. Chapter 5 provides the crystal structures of three polymorphic forms of β-hairpins. The structure of BH1P8 provides new insights into the packing of hairpins inclined orthogonally to each other. The two polymorphic forms differ not only in their modes of packing in crystals but also in the strong and weak interactions stabilizing the packing arrangements. The polymorphic forms of DPUFP8 differ only in the content of the solvent in the asymmetric unit and the role it plays in bridging the symmetry related pairs of molecules. The polymorphic form YDPPP8 crystallized in a completely different space group, revealing a completely different mode of packing and also the cocrystallized solvent participating in a different set of interactions. Crystal parameters BH1P8: C54H78N8O11.H2O; P212121; a = 18.7511 (9), b = 23.3396 (11) Å, c = 28.1926 (13)Å; Z = 8; R = 0.1208, wR2 = 0.2898. DPUFP8: C55H84N8O11. (0.5) H2O; P21; a = 18.0950 (4), b = 23.0316 (5) Å, c = 18.6368 (5) Å, β = 117.471 (2); Z = 4; R = 0.0915, wR2 = 0.2096. YDPPP8: C56H83N8O12. (1.5) H2O; P21; a = 14.3184 (8), b = 18.9924 (9) Å, c = 25.1569 (14) Å, β = 105.590 (4); Z = 4; R = 0.1249, wR2 = 0.2929. Chapter 6 provides a comprehensive overview of the β-hairpin peptide crystal structures published in the literature as well as those included in the thesis. The hairpins are classified based on the residues composing the β-strands and the mode of their packing in the crystals. In the crystal structures the hairpins are observed to adopt either a Type II′ or Type I′β-turns. The indexing of the crystal faces of a few representative hairpin peptides crystallographically characterized in this thesis, provides a rational explanation for the preferential growth of the crystals in certain directions, when correlated with the strong directional forces (hydrogen bonding) and weak interactions (van der Waals, aromatic-aromatic) observed in the crystal packing. The insights gained by these studies would be highly valuable in understanding the nucleation and growth of β-hairpin peptides and the formation of β-sheet structures. Appendix I describes the Cambridge Structural Database (CSD) analysis of the conformational preferences of the proline residues found in the peptide crystal structures. The frequency distributions of the backbone φ, ψ and ω and side chain χ1, χ2, χ3, χ4 and θ torsion angles of the proline residues are calculated, tabulated and represented as graphical plots. The correlation between the backbone and endocyclic torsion angles provides for a clear evidence of the role of a particular torsion variable χ2 in deciding the state of puckering. In addition, the endocyclic bond angles also appear to be correlated, relatively strongly, with the χ2 torsion. This provides a geometrical explanation of the factors governing the puckering of the proline ring.

The aim of this study is to investigate the effectiveness of conceptual change text oriented instruction accompanied with analogies over traditionally designed chemistry instruction on overcoming 10th grade students&rsquo / misconceptions, their understanding of rate of reaction concepts and their attitude towards chemistry as a school subject. 42 tenth grade students from two classes of a chemistry course taught by the same teacher at a public high school in &Ccedil / anakkale involved in the study. The study was carried out in Spring Semester of 2005-2006 Education Year. Two groups of students participated in the study. One group was called Experimental Group and instructed with conceptual change texts oriented instruction accompanied with analogies and the other group was called Control Group and was instructed with traditionally designed chemistry instruction over a period of four weeks. To investigate the effectiveness of the treatment, Rate of Reaction Concepts Test and Attitude Scale Towards Chemistry as a school subject were administered to both groups of students at the beginning and at the end of the treatment period. To evaluate students&rsquo / science process skills, Science Process Skills Test was administered to both groups of students before the treatment. MANCOVA was used to test the hypothesis of the study. The results of the study indicated that students instructed with conceptual change texts oriented instruction accompanied with analogies gained higher average scores in Rate of Reaction Concepts Test than the students instructed with traditionally designed chemistry instruction. Results and strategies that were developed for the present study may be used by science teachers to reduce and eliminate students&rsquo / misconceptions about rate of reaction concepts.