The research presented in this thesis investigates eye injuries caused by blunt impacts and blast overpressure. This research represents part of an ongoing investigation to accurately quantify and predict eye injuries and injury mechanisms for various loading schemes. It has been shown that blunt trauma can cause severe eye injuries but it remains undecided whether blast overpressure alone can cause eye injury. Presented herein are four experimental studies that quantify eye injuries and implement a technique for predicting injury risk. Isolated porcine or human eyes were subjected to various loading conditions consisting of blunt projectiles, water streams, remote control helicopter blades, and blast overpressure. All eyes were prepared in a similar manner that required the insertion of a miniature pressure sensor into the globe through the optic nerve. This sensor measured intraocular pressure throughout each event. Using previously published injury risk curves, this intraocular pressure data was used to predict the injury risk for four eye injuries: hyphema, lens damage, retinal damage, and globe rupture. Injuries sustained were quantified upon direct inspection of the globe following testing. No serious eye injuries were observed for any of the tests and all tests resulted in low predicted injury risks consistent with the lack of observed injury. The research presented in this thesis provides a robust low injury level dataset for eye injuries. This data could be useful for designing and validating computational models and anthropomorphic test device eyes, and serves as a basis for future work with more dangerous projectiles and higher pressure levels. / Master of Science

Multimodal micron-sized spherical aluminum powders were subjected to the detonation products of a gaseous oxyacetylene mixture. The objective was to analyze the blast enhancement from the combustion of non-uniform-sized aluminum particles. These multimodal aluminum powders consisted of a 50/50 mixture by mass of larger (~30 μm) and smaller (~1-10 μm) particles. Experiments were conducted at the large-scale Virginia Tech Shock Tube Research Facility to measure blast pressure, impulse, and heat release efficiency during combustion in these detonations. These results were compared against oxyacetylene detonations conducted with the addition of unimodal aluminum particles approximately 1, 10, 30, and 95 μm in diameter. These experiments were controlled by maintaining a particle mass concentration of 200 g/m3, a constant volume of air for particle dispersion, and a consistent size for the gaseous oxyacetylene explosive charge of 0.11 m3. This approach ensured that any variations in explosive output were due to the characteristics of the aluminum powder. For unimodal aluminum, the combustion of 1 μm aluminum powder yielded the highest increase in blast pressure, impulse, and heat of combustion efficiency whereas H-95 provided the least amount of blast enhancement. These results showed an inverse relationship where decreasing aluminum particle size resulted in increased blast output, a phenomenon driven by the shorter combustion times of smaller particles. For multimodal aluminum combustion, the performance of these powders exceeded the pressure and impulse performance of their unimodal counterparts. The heat of combustion efficiency—defined as the ratio of energy driving the shock wave to the total energy available—was estimated using a two-part blast scaling methodology. The first step in this process used Sachs' blast scaling laws to infer time-dependent energy release contributing initially to blast pressure and impulse. The second step introduced a new modified Sachs scaling technique to account for late-time energy release contributing solely to blast impulse. This scaling approach addressed the previously neglected impact of delayed aluminum combustion on blast behavior. This two-part scaling approach revealed that the combustion of multimodal aluminum powders in oxyacetylene detonations resulted in 75.1%-85.3% of the available heat of combustion contributing to blast pressure and impulse compared to the 30.8%-74.6% provided by unimodal aluminum powders. These results suggest that the combustion of multimodal aluminum powder results in more powerful and efficient detonations, providing a technique to improve and optimize energetic performance. / Master of Science / Micron-sized spherical aluminum powders serve as additives to enhance the performance of propellants, pyrotechnics, and explosives. Previous laboratory-scale research has shown that aluminum's ignition and combustion characteristics are influenced by particle size, with smaller particles tending to ignite more quickly and release more energy than larger ones. However, little research has been directed at understanding the impact of particle size distribution on aluminum combustion, and whether combining smaller particles with larger ones can enhance the overall combustion reactivity and efficiency. This work investigated the impact of mixed (multimodal) aluminum combustion on the blast pressure, impulse, and overall heat of combustion efficiency of oxyacetylene detonations. To achieve this, the experimental procedure consisted of three testing series: (i) oxyacetylene detonations without aluminum powder; (ii) unimodal aluminum combustion in oxyacetylene detonations; and (iii) multimodal aluminum combustion in oxyacetylene detonations. These blast experiments were conducted using the large-scale Virginia Tech Shock Tube Research Facility. This detonation-driven shock tube maintained a constant aluminum particle mass concentration of 200 g/m3, a constant volume of air for particle dispersion, and a consistent size for the gaseous oxyacetylene explosive charge of 0.11 m3. This experimental design ensured that any variations in explosive output were due to the explosive charge size and particle characteristics of the aluminum powder. Results showed that introducing unimodal aluminum powder into oxyacetylene detonations significantly enhanced blast pressure, impulse, and energy efficiency compared to the control case of pure oxyacetylene. Furthermore, a reduction in the mean particle size of aluminum powder resulted in greater blast output, revealing an inverse relationship where smaller particle sizes led to higher blast performance due to their faster reaction rates. For multimodal aluminum powders, the use of mixed particle sizes produced even greater blast pressure, impulse, and energy efficiency than their unimodal counterparts. These findings indicate that the combustion of multimodal aluminum powder produces more powerful and efficient detonations, providing an approach to enhance and optimize energetic performance.

Explosions cause the majority of injuries in the current conflicts, accounting for 79% of combat related injuries (Ramasamy et al. 2008). Blast overpressure from explosions can cause barotrauma to the lungs and the brain. Blast-induced mild traumatic brain injury has been labeled the "signature wound" of current military conflicts in Iraq and Afghanistan (Snell and Halter 2010). In addition to elevated number of blast-induced traumatic brain injuries due to increased military conflicts overseas and the usage of improvised explosive devices, the incidence of blast-induced polytrauma has risen due to the prevalence of terrorist events around the world (Arnold et al. 2004, Rodoplu et al. 2004). Blast-induced polytrauma is a major concern as lung injury can cause immediate mortality and brain injury causes long-lasting neurocognitive impairment. There is a critical lack of understanding the pathology of blast-induced polytrauma since the needs are multifaceted and therefore few options for treatment. Thus, the research presented in this dissertation required the development of a military-relevant blast polytrauma model to examine injury pathology and subsequently study the effects of hemostatic nanoparticle therapy after blast-induced polytrauma. The pre-clinical model was characterized and static overpressure thresholds were determined for lethality risk. It was confirmed to have many of the classic hallmarks of primary blast lung injury (PBLI), as well as blast-induced neurotrauma (BINT) (Clemedson 1950). Global hemorrhaging was found in the lungs and well as reduced oxygen saturation. Markers of astrogliosis and blood-brain barrier disruption were examined in the amygdala after blast. The novel nanoparticle configuration (hemostatic dexamethasone-loaded nanoparticles (hDNP) functionalized with a peptide that binds with activated platelets) was investigated and hypothesized to increase survival, reduce cellular injury and reduce anxiety-like disorders after blast polytrauma. After investigating hDNP, it was found that the hDNP treatment benefited survival percentage after injury as well as reduced percent hemorrhage in the lungs and improved physiology. Elevated anxiety parameters found in the controls were lower as compared to the hDNP group. Glial fibrillary acidic protein (GFAP) and cleaved caspase-3 were significantly elevated in the controls compared to the hDNP group in the amygdala. SMI-71 was also significantly elevated with the hDNP and hemostatic nanoparticle (hNP) treatments, similar to sham. In addition to the nanoparticles offering immediate life-saving qualities, administration of hemostatic nanoparticles improved amygdala pathology attributed to secondary mechanisms of blast injury, including blood-brain barrier disruption. This model of polytrauma can serve as a foundation for detailed pathological studies as well as testing therapeutics for injury modalities. References (Abstract) Arnold, J. L., P. Halpern, M. C. Tsai and H. Smithline (2004). "Mass casualty terrorist bombings: a comparison of outcomes by bombing type." Ann Emerg Med 43(2): 263-273. Clemedson, C. J., Granstom, S.A. (1950). "Studies on the genesis of "rib markings" in lung blast injury." Acta Physiol Scand. 21: 131-144. Ramasamy, A., S. E. Harrisson, J. C. Clasper and M. P. Stewart (2008). "Injuries from roadside improvised explosive devices." J Trauma 65(4): 910-914. Rodoplu, U., Arnold, J. L., Tokyay, R., Ersoy, G., Cetiner, S., Yucel, T. (2004) "Mass-casualty terrorist bombings in Istanbul, Turkey, November 2003: reports of the events and the prehospital emergency response." Prehosp Disaster Med 19(2):133-145. Snell, F. I. and M. J. Halter (2010). "A signature wound of war: mild traumatic brain injury." J Psychosoc Nurs Ment Health Serv 48(2): 22-28. / Ph. D.

The ability to compare two biological sequences is extremely valuable, as matches can suggest evolutionary origins of genes or the purposes of particular amino acids. Results of such comparisons can be used in the creation of drugs, can help combat newly discovered viruses, or can assist in treating diseases. Unfortunately, the rate of sequence acquisition is outpacing our ability to compute on these data. Further, traditional dynamic programming algorithms are too slow to meet the needs of biologists, who wish to compare millions of sequences daily. While heuristic algorithms improve upon the performance of these dated applications, they still cannot keep up with the steadily expanding search space. Parallel sequence search implementations were developed to address this issue. By partitioning databases into work units for distributed computation, applications like mpiBLAST are able to achieve super-linear speedup over their sequential counterparts. However, such implementations are limited to clusters and require significant effort to work in a grid environment. Further, their parallelization strategies are typically specific to the target sequence search, so future applications require a reimplementation if they wish to run in parallel. This thesis analyzes the performance of two versions of mpiBLAST, noting trends as well as differences between them. Results suggest that these embarrassingly parallel applications are dominated by the time required to search vast amounts of data, and not by the communication necessary to support such searches. Consequently, a framework named gridRuby is introduced which alleviates two main issues with current parallel sequence search applications; namely, the requirement of a tightly knit computing environment and the specific, hand-crafted nature of parallelization. Results show that gridRuby can parallelize an application across a set of machines through minimal implementation effort, and can still exhibit super-linear speedup. / Master of Science

Blast-induced neurotrauma (BINT) is a major societal concern due to the complex expression of neuropathological disorders after exposure to blast. Disruptions in neuronal function, proximal in time to the blast exposure, may eventually contribute to the late emergence of the clinical deficits. Besides complications with differential clinical diagnosis, the biomolecular mechanism underlying BINT that gives rise to cognitive deficits is poorly understood. Some pre-clinical studies have demonstrated cognitive deficits at an acute stage following blast overpressure (BOP) exposure. However, the behavioral deficit type (e.g., short term memory) and the mechanism underlying injury prognosis that onsets the cognitive deficits remains to be further investigated. An established rodent model of blast neurotrauma was used in order to study impaired behavioral and neuropathological outcomes following blast. Anesthetized rats were exposed to a calibrated BOP using a blast simulator while control animals were not exposed to BOP. Behavioral changes in short term memory and anxiety were assessed with standard behavioral techniques (novel objected recognition paradigm and light and dark box test) at acute and chronic stages (range: 3 hours -- 3 months). In addition, brains were assayed for neurochemical changes using proton magnetic resonance spectroscopy (MRS) and neuropathology with immunohistochemistry in cognitive regions of brain (hippocampus, amygdala, frontal cortex and nucleus accumbens) Early metabolic changes and oxidative stress were observed along with a compromise in energy metabolism associated with sub-acute (7 days following BOP exposure) active neurodegeneration and glial scarring. Data suggested GABA shunting pathway was activated and phospholipase A2 regulated arachadonic acid pathway may be involved in cellular death cascades. In addition, increased myo-inositol levels in medial pre-frontal cortex (PFC) further supported the glial scarring and were associated with impaired working memory at a sub-acute stage (7 days) following BOP exposure. Chronic working memory issues and anxiety associated behavior could be related to chronic activation of microglia in hippocampus and astrocytes in amygdala respectively. Furthermore, these results from MRS could be directly translated into clinical studies to provide a valuable insight into diagnosis of BINT, and it is speculated that gliosis associated markers (myo-inositol) may be a potential biomarker for blast-induced memory impairment. / Ph. D.

In this experiment, average calcaneal fracture force is measured across male and female groups. The purpose of this experiment is an analysis of alternatives exploring the importance of sex-based criteria in models representing injuries typical in underbody blast environments. Seventeen (17) right legs were harvested at the knee from cadavers representing three anthropometries: 50th percentile male (6), 75th percentile female (6), and 5th percentile female (5). Care was taken to preserve anatomically correct geometry as the legs were cut to equal lengths, the tibia and fibula were potted in Dyna-Cast®, flesh and ligaments were excised from the inferior surface of the calcaneus, and a small Dyna-Cast® pad was poured and sanded flat – interfacing with the exposed calcaneal surface. Each test specimen was mounted in a custom fixture and exposed once to high-rate axial loading characterized by a constant acceleration and 25.4mm intrusion, achieving an average speed of 4.7m/s (σ = 0.3m/s) in 10ms. Input acceleration was measured by an Endevco 7264c accelerometer and a Denton 2513 six-axis load cell measured reaction force proximal to the specimen. A VR Phantom v9.1 camera recorded x-ray imagery at 2k frames per second. Data were collected by a TDAS Pro data acquisition system at 20k samples per second and filtered in accordance with SAE J211. Time of fracture, established through x-ray imagery, was used to determined fracture force from the electronically synchronized load-cell data. 100% injury was recorded. Average calcaneus fracture forces were reported as follows: 5406N (σ = 780N) for 50th percentile males, 4130N (σ = 1061N) for 75th percentile females, and 2873N (σ = 1293N) for 5th percentile females. Statistical significance was established between the reported averages according to three ANOVA tests: One-way (p = 0.0054), Brown-Forsythe (p = 0.0091), and Welch's (p = 0.0156). Unpaired Student's t-test confirmed significant differences between 50th percentile male vs 75th percentile female (p = 0.0469) and 50th percentile male vs 5th percentile female (p = 0.0030); the t-test did not show significance between the two female groups (p = 0.1315). Average impulse-to-fracture was calculated for each group and found to be not statistically significant. / Master of Science / A marked shift can be found in combat wound epidemiology towards a predominance of extremity injuries sustained from explosives. The Warrior Injury Assessment Mannequin (WIAMan) Project sought to develop a baseline dataset of post-mortem human surrogate responses to realistic explosive loading and correlate it to a highly instrumented mannequin for the further development of combat vehicles and personal protective gear. The following experiment exists within the WIAMan paradigm as an analysis of alternatives exploring the adequacy of the above mentioned baseline dataset in directly representing both male and female injuries. More specifically, this experiment interrogates the differences in average fracture forces between male and female calcanei across three anthropometries: 50th percentile male, 75th percentile female, and 5th percentile female. Testing was carried out on 17 right cadaver legs cut to equal lengths, potted proximally in Dyna-Cast®, with the inferior surface of their calcanei exposed; a small Dyna-Cast® pad was poured for each calcaneus and sanded flat. Each test specimen was fixed to a Denton 2513 six-axis load cell proximally and exposed to a high-rate, constant acceleration, 25.4mm displacement aligned with the calcaneus along the long axis of the leg bones. Fracture time, established through x-ray images recorded at 2k frames per second with a VR Phantom V9.1 camera, was used to determine load cell force measurement at fracture. Average calcaneus fracture forces were reported as follows: 5406N (σ = 780N) for 50th percentile males, 4130N (σ = 1061N) for 75th percentile females, and 2873N (σ = 1293N) for 5th percentile females. Statistical significance was established between the reported averages according to three ANOVA tests: One-way (p = 0.0054), Brown-Forsythe (p = 0.0091), and Welch's (p = 0.0156). Unpaired Student's t-test confirmed significant differences between 50th percentile male vs 75th percentile female (p = 0.0469) and 50th percentile male vs 5th percentile female (p = 0.0030); the t-test did not show significance between the two female groups (p = 0.1315). Average impulse-to-fracture was calculated for each group and found to be not statistically significant.

As improving technology is making it easier to select or engineer DNA sequences that produce dangerous proteins, it is important to be able to predict whether a novel DNA sequence is potentially dangerous by determining its taxonomic identity and functional characteristics. These tasks can be facilitated by the ever increasing amounts of available biological data. Unfortunately, though, these growing databases can be difficult to take full advantage of due to the corresponding increase in computational and storage costs. Entropy scaling algorithms and data structures present an approach that can expedite this type of analysis by scaling with the amount of entropy contained in the database instead of scaling with the size of the database. Because sets of DNA and protein sequences are biologically meaningful instead of being random, they demonstrate some amount of structure instead of being purely random. As biological databases grow, taking advantage of this structure can be extremely beneficial. The entropy scaling sequence similarity search algorithm introduced here demonstrates this by accelerating the biological sequence search tools BLAST and DIAMOND. Tests of the implementation of this algorithm shows that while this approach can lead to improved query times, constructing the required entropy scaling indices is difficult and expensive. To improve performance and remove this bottleneck, I investigate several ideas for accelerating building indices that support entropy scaling searches. The results of these tests identify key tradeoffs and demonstrate that there is potential in using these techniques for sequence similarity searches. / Master of Science / As biological organisms are created and discovered, it is important to compare their genetic information to known organisms in order to detect possible harmful or dangerous properties. However, the collection of published genetic information from known organisms is huge and growing rapidly, making it difficult to search. This thesis shows that it might be possible to use the non-random properties of biological information to increase the speed and efficiency of searches; that is, because genetic sequences are not random but have common structures, the increase of known data does not mean a proportional increase in complexity, known as entropy. Specifically, when comparing a new sequence to a set of previously known sequences, it is important to choose the correct algorithms for comparing the similarity of two sequences, also known as the distance between them. This thesis explores the performance of entropy scaling algorithm compared to several conventional tools.

This research explored the energy release of pure oxyacetylene and aluminized oxyacetylene detonations and their blast efficiency. A numerical model was developed using blastFoam to accurately capture shock wave parameters using a compressed gas balloon method. For this method, the explosive was replaced by a compressed gas balloon with calibrated initial conditions to replicate the explosive's blast characteristics. The numerical model was validated with experimental data from 0.11 m3 oxyacetylene detonations acquired by Cheney (2024) in the large-scale shock tube research facility at VA Tech (VTSTRF). A series of studies were carried out in this process of model development including: the preliminary building of the model domain with the shock tube geometry and approximation of specific energy of oxyacetylene, a symmetry study, an all-direction mesh refinement study, and an x-direction mesh refinement study. The goal of these studies was to develop a model that accurately captures the energy release from the 0.11 m3 detonation in a sufficiently quick manner. Once the numerical model was developed, it was used to determine the energy release of detonations with varying oxyacetylene volumes and H-10 aluminum concentrations as compared to data collected in the VTSTRF by Cheney (2024) and Kamide and Jacques (2024). A comparison of energy values was carried out against a traditional approach of blast scaling. Similar relationships were found between aluminum concentration and total energy of detonation and blast efficiency. The blastFoam numerical model enables a simpler method of capturing energy release from complex non-ideal detonations, requiring input dependent only on specific energy of the balloon and balloon volume. / Master of Science / This research explored the energy release of pure oxyacetylene and aluminized oxyacetylene detonations and their blast efficiency. A numerical model was developed using blastFoam, a detonation-specific add-on to OpenFoam-9. The shock wave parameters were captured using a compressed gas balloon method. This numerical modeling method was chosen for its simplicity, quick runtime, and ease of determining total energy in the balloon. For this method, the explosive was replaced by a compressed gas balloon with calibrated initial conditions that replicate the explosive's blast characteristics. These blast wave characteristics include the pressure-time history and peak pressure and impulse at the pressure sensors. The numerical model was validated with experimental data from 0.11 m3 oxyacetylene detonations acquired by Cheney (2024) in the large-scale shock tube research facility at VA Tech (VTSTRF). A series of studies were carried out in this process of model development including: the preliminary building of the model domain with the shock tube geometry, boundary conditions, and approximation of specific energy of oxyacetylene, a symmetry study, an all-direction mesh refinement study, and an x-direction mesh refinement study. The goal of these studies was to develop a model that accurately captures the energy release from the 0.11 m3 detonation in a reasonably quick manner. Once the numerical model was developed, it was used to determine the energy release of detonations with varying oxyacetylene volumes and H-10 aluminum concentrations as compared to data collected in the VTSTRF by Cheney (2024) and Kamide and Jacques (2024), respectively. A comparison of total detonation energy was carried out against a traditional approach of blast scaling. Similar relationships were found between aluminum concentration and total energy of detonation and blast efficiency. As aluminum mass concentration increased, the total detonation energy increased and blast efficiency decreased. The blastFoam compressed gas balloon numerical model enables a simpler method of accurately capturing energy release from complex non-ideal detonations, requiring input dependent only on specific energy of the balloon and balloon volume. Future work includes applying this numerical model to different aluminum particle sizes and multimodal aluminum particle distributions.

<p>Between October 2001 and May 2012 approximately 70% of U.S. military personnel killed in action and 75% wounded in action were the direct result of exposure to an explosion. As of 2008, it was estimated that close to 20% of all Operation Iraqi Freedom and Operation Enduring Freedom (OIF/OEF) veterans had sustained some form of traumatic brain injury (TBI). Further, blast exposure is also a civilian problem due to the increased usage of explosives in terrorist attacks. Blast injury research has historically focused on the pulmonary system and the other air-containing organs which have been shown through extensive experimentation to be susceptible to blast overpressure injury. A shift in injury pattern during recent conflicts is characterized by decreased incidence of pulmonary injuries with an increase in TBI thought to be associated with blast exposure. This increase in observation of blast TBI has resulted in a large research effort to understand mechanisms and thresholds. However, due to the relatively sudden shift, much of this research is being conducted without a proper understanding and consideration of blast mechanics and interspecies scaling effects.</p><p>This dissertation used experimental and computational finite element (FE) analysis to investigate some large questions surrounding blast TBI research. An experimental investigation was conducted to determine the effects of modern thoracic body armor usage on blast pressure exposure seen by the body. To improve FE modeling capabilities, brain tissue mechanics in common blast TBI animal model species were investigated experimentally and computationally to determine viscoelastic constitutive behavior and measure interspecies variation. Meta-analysis of blast pulmonary literature was conducted to update interspecies scaling and injury risk models. To derive interspecies scaling and injury risk models for blast neurotrauma endpoints a meta-analysis of existing experimental data was used.</p><p>This dissertation makes major contributions to the field of injury biomechanics and blast injury research. Research presented in this dissertation showed that modern thoracic body armor has the ability to lower the risk of pulmonary injury from blast exposure by attenuating and altering blast overpressure. The study shows that the use of soft body armor results in the pulmonary injury threshold being similar to that for neurotrauma. The use of hard body armor results in the threshold for pulmonary injury occurring at higher levels than that of neurotrauma. This finding is important, as it helps to explain the recent shift in injury types observed and highlights the importance of continued widespread usage of body armor not only for ballistic protection but for protection from blast as well.</p><p>This dissertation also shows the importance of interspecies scaling for investigation of blast neurotrauma. This work looks at existing in vivo animal model data to derive appropriate scaling across a wide range of brain size. Appropriate scaling for apnea occurrence and fatality for blast isolated to the head was found to be approximately equal to a characteristic length scaling of brain size, assuming similar brain geometry. By combining the interspecies scaling developed and existing tests data, injury risk models were derived for short duration blast exposures.</p><p>The contributions and conclusions of this dissertation serve to inform the injury biomechanics field and to improve future research efforts. The consideration by researchers of the recommendations presented in this dissertation for in vivo animal model testing will serve to maximize the value gained from experimentation and improve our understanding of blast injury mechanisms and thresholds. The injury risk models presented in this work help to improve our ability to prevent, diagnose, and treat blast neurotrauma.</p> / Dissertation

Expressed Sequence Tags (ESTs) são amostras de trechos de genes, que funcionam como moldes na síntese de proteínas. Como a quantidade de ESTs coletados nos últimos anos é muito grande, o uso de computadores tornou-se imprescindível para a identificação de genes, proteínas e para a descoberta de genes homólogos. Este trabalho propõe uma metodologia e implementa uma ferramenta para a visualização de ESTs através de um grafo para auxiliar biólogos na exploração e na descoberta de conhecimento sobre estas seqüências. A metodologia inclui agrupamento usando um programa montador de seqüências e, conseqüentemente, a transformação dos grupos em nós de um grafo. O algoritmo BLAST é usado para procurar alinhamentos entre seqüências, representando-os posteriormente por arestas entre as seqüências mais similares. Para a visualização do grafo utilizamos e modificamos a ferramenta TG WikiBrowser conectada a um banco de dados. O resultado é uma ferramenta interativa baseada em código livre e robusto que funciona em ambientesWindows e Linux. Ela possibilita a fácil exploração do grafo, com diversas funcionalidades como, por exemplo: a expansão e filtragem do grafo, a busca por rótulos ou trechos de seqüências e a visualização detalhada de seqüências e grupos de seqüências. Com isso, os biólogos e especialistas em bioinformática ganham mais uma alternativa de investigação da genética / Expressed Sequence Tags (ESTs) are samples of gene stretches, which play the role of templates in synthesis of proteins. Since the amount of collected ESTs on the past few years is enormous, the use of computers has become essential to fields like gene and protein identification, and gene homology. This work proposes a methodology and a tool for visualization of ESTs as a graph for aiding biologists on exploration and on knowledge discovery about these sequences. The methodology includes clustering of ESTs using an assembly program and, consequently, the transformation of the groups in nodes of a graph. BLAST algorithm is used to search alignments among sequences, later representing them as edges between the most similar sequences. For the graph visualization, we adapted TGWikiBrowser software connected to a database. The result is a robust and open source interactive tool forWindows and Linux. It allows easy graph exploration, with various functionalities, for example: graph expansion and filtering, searching for label or sequence stretches, and detailed visualization of sequences and groups of sequences. Therefore, we hope biologists can count on one more option in genetics research