Gamma-hydroxybutyrate (GHB) is an endogenous compound in the human body, found in regions of the mammalian brain and believed to be a cerebral neurotransmitter.1,2 GHB also acts as a powerful central nervous system depressant commonly used as a “date rape” drug due to its hypnotic and sedative properties.1 The drug has also been used medicinally to treat alcohol withdrawal, opiate-withdrawal syndrome, and narcolepsy.3–5 Toxicological analysis of GHB in drug facilitated sexual assault (DFSA) cases is typically performed using blood and urine specimens.1 However, due to the endogenous nature of GHB, toxicological interpretation of these biological specimens can be complex and challenging.1,4 Additionally, urine and blood analysis of GHB can be impacted by sample collection, sample analysis times, and sample storage conditions.6,7 Due to the challenges and limitations associated with blood and urine analysis of GHB along with the prominence of GHB in DFSA cases, it would be beneficial to determine the possibility of GHB analysis using alternative biological matrices. The primary goal of this research was to develop a sample preparation method that could accurately and reliably identify and quantify GHB in oral fluid, as an alternative biological matrix. Additionally, this research was carried out to compare the identification and quantitation capabilities of GHB in oral fluid to that of traditional biological matrices, specifically urine and blood. The methods employed in this study utilized gas chromatography – mass spectrometry (GC-MS) instrumentation in order to correctly identify GHB. A deuterated internal standard, GHB-d6, was used to quantify all samples. The methods were assessed using the parameters set forth by the Scientific Working Group of Forensic Toxicologists (SWGTOX) for quantitative analysis methods. The following factors were considered: calibration model, bias, precision, limit of detection and quantitation, carryover, and interferences. Urine and blood samples were prepared using 200 uL of urine (UTAK Laboratories, Inc., Valencia, CA, U.S.A.) or blood (Equitech-Bio Inc., Kerrville, TX, U.S.A.), varying amounts of the 200 mg/L working calibrator and control solution prepared using certified reference standards (Cerilliant, Round Rock, TX, U.S.A.), and 50 uL of 100 mg/L working internal standard solution resulting in an internal standard concentration of 25 mg/L in each sample. Solid phase extraction (SPE) was performed using United Chemical Technologies (UCT), Inc. (Bristol, PA, U.S.A) Clean Screen GHB columns (ZSGHB020) on all samples.1 Samples were reconstituted, derivatized, and analyzed using GC-MS. Oral fluid samples were prepared using 1.0 uL of drug-free oral fluid, and 1.0 mg/mL (as salt) in methanol GHB received from Cerilliant. The samples were spiked with 1 uL of 1.0 mg/mL (as salt) in methanol GHB-d6 received from Cerilliant. Each sample had an internal standard concentration of 10 mg/L. Samples were fortified with 100 uL of ethyl acetate, and derivatized with 100 uL of bis(trimethyl)trifluoroacetamide (BSTFA) with 1% Trimethylchlorosilane (TMCS) received from Cerilliant. The samples were incubated, and analyzed using GC-MS.8 All analyses were conducted using an Agilent 7890A GC system, Agilent 5975C Mass Detector System (MSD), and an Agilent 7683B Autosampler (Agilent Technologies Inc. Santa Clara, CA). The chromatographic component was carried out using an Agilent HP5-MS 30m x 250um x 0.25um capillary column and an Agilent HP- 5MS 15m x 250um x 0.25um capillary column. All data was analyzed using Agilent MSD ChemStation software (version E.02.02.1431). The method has a total length of 12.75 minutes. Selective ion monitoring (SIM) was used to monitor the ions of interest for each analyte. GHB-d6 was monitored using the ions 239, 240, and 241. GHB was monitored using the ions 233, 234, 235.1 Results revealed that GHB and GHB-d6 could be identified and differentiated due to their fragmentation patterns. All calibration curves for the three matrices exhibited R2 values > 0.98 using a linear dynamic range of 5-100 mg/L with a minimum of four calibration points. The limit of detection for the three matrices was determined to be 1 mg/L, and the limit of quantitation for the three matrices was determined to be 5 mg/L. Bias and precision were analyzed at concentrations of 8 mg/L, 45 mg/L, and 90 mg/L for each matrix. All urine and blood samples were calculated to be within the acceptance range of +20% bias and +20% coefficient of variation. Oral fluid samples were outside of the +20% acceptance range for both bias and coefficient of variation. The highest concentration analyzed that did not produce carryover into subsequent matrix blanks was found to be 350 mg/L for each matrix. Significant interferences were found to be present in urine and blood samples, but negligible for all oral fluid samples. This research illustrates that the developed sample preparation method can be used to accurately and reliably identify GHB in oral fluid. Additionally, this research suggests that the quantitation capabilities of GHB in oral fluid are not as accurate and precise as those of urine and blood. Therefore, the developed method has better qualitative analysis capabilities, while the urine and blood methods have better quantitative analysis capabilities for forensic toxicology casework.

Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2015-10-22T18:57:51Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Israel Filho.pdf: 724723 bytes, checksum: 782b45f9225d11add525dd331ff52d0e (MD5) / Made available in DSpace on 2015-10-22T18:57:51Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Israel Filho.pdf: 724723 bytes, checksum: 782b45f9225d11add525dd331ff52d0e (MD5) Previous issue date: 2015-03-13 / CNPq / O DFSA (Dynamic Framed Slotted ALOHA) é um protocolo anticolisão que vem sendo amplamente adotado para resolver problemas de colisão em sistemas RFID (Radio Frequecy IDentification). De acordo com esse protocolo, o tamanho do quadro subsequente ao quadro inicial é ajustado dinamicamente com base no número de etiquetas que disputaram por slots no quadro anterior. Intuitivamente, a precisão do estimador utilizado poderá afetar o desempenho na identificação de etiquetas. Assim, diversas propostas de estimadores vêm contribuindo para melhorar a precisão da quantidade de etiquetas, diminuindo, desse modo, o atraso de identificação. Contudo, pouca atenção tem sido dada na identificação de um grande volume de etiquetas. Os desafios estão em prover um estimador acurado e com baixo custo computacional. Esta dissertação propõe uma extensão ao estimador Chen II, o qual, originalmente, apesar de possuir um baixo custo computacional e boa precisão, e incapaz de lidar com a identificação de grandes volumes de etiquetas sem perda significativa de eficiência. Os resultados mostram que a extensão proposta consegue uma eficiência muito próxima de 36,8% para a identificação de até 10.000 etiquetas. Esse percentual representa a eficiência máxima do protocolo de acesso ao meio utilizado. / The DFSA (Dynamic Framed Slotted ALOHA) is an anti-collision protocol that has been widely adopted to solve collision problems in RFID systems ( textit Radio Frequecy IDentification). According to the protocol, the size of the table below to the starting frame is dynamically adjusted based on the number of labels that disputed by slots in the table above. Intuitively, the accuracy of the estimator used can affect performance in identifying labels. Thus, several proposals estimators have contributed to improve the accuracy of the number of labels, and thus decrease the delay identification. However, little attention has been given to the identification of a large volume of labels. The challenges are to provide an accurate and computationally efficient estimator. This paper proposes an extension to the estimator Chen II, which originally despite having a low computational cost and good accuracy, it is unable to deal with the identification of large volumes of labels with no significant loss of efficiency. The results show that the proposed extension can very closely efficiency of 36.8 % for identifying up to 10,000 labels. This percentage is the maximum efficiency of the access protocol to the medium used.

Drug-facilitated sexual assaults are a public health and safety concern. Liquid chromatography paired with tandem mass spectrometry is theoretically capable of detecting the scope of drugs commonly encountered in these types of cases. An analytical method was developed for the quantitative analysis of 40 drugs designated by Academy Standards Board 121 “Standard for the Analytical Scope and Sensitivity for Forensic Toxicological Testing of Urine in Drug Facilitated Crime” (ASB 121). The targeted analytes spanned a range of drug classes including antidepressants, antihistamines, barbiturates, benzodiazepines, cannabinoids, stimulants, and opioids. The final method utilized supported liquid extraction, followed by liquid chromatography tandem mass spectrometry with electrospray ionization in simultaneous positive and negative mode. Multiple reaction monitoring allowed quantification of analytes along with stable isotope internal standards. Validation parameters assessed included linearity, bias, precision, limit of detection, lower limit of quantitation, interference, and ion suppression or enhancement. The utilized sample preparation method was able to extract 36 of the 40 target analytes and the developed analytical method was able to detect and quantify all analytes to the sensitivities required by ASB 121.

The major advantages of radio frequency identification (RFID) technology over barcodes are that the RFID-tagged objects do not require to be in line-of-sight with the reader for their identification and multiple objects can be read simultaneously. But when multiple objects are read simultaneously there is always a problem of collision which reduces the efficiency of the system. This thesis presents a comprehensive study of the dynamic framed slotted ALOHA (DFSA)-based anti-collision multi-tag identification algorithms for passive RFID system. Performance of various DFSA algorithms is compared through extensive simulation results. In addition, a number of simple performance improvement techniques have also been investigated in this thesis, including improved estimation techniques for the number of tags in each read cycle and a low-complexity heuristic stopping criterion that can be easily implemented in the practical system.

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-11-23T21:24:44Z No. of bitstreams: 1 Dissertação - Walfredo da Costa Lucena Filho.pdf: 2083187 bytes, checksum: 72f63311dba60bbea7ef2d5cc474c601 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-11-30T19:51:08Z (GMT) No. of bitstreams: 1 Dissertação - Walfredo da Costa Lucena Filho.pdf: 2083187 bytes, checksum: 72f63311dba60bbea7ef2d5cc474c601 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-11-30T19:55:39Z (GMT) No. of bitstreams: 1 Dissertação - Walfredo da Costa Lucena Filho.pdf: 2083187 bytes, checksum: 72f63311dba60bbea7ef2d5cc474c601 (MD5) / Made available in DSpace on 2015-11-30T19:55:40Z (GMT). No. of bitstreams: 1 Dissertação - Walfredo da Costa Lucena Filho.pdf: 2083187 bytes, checksum: 72f63311dba60bbea7ef2d5cc474c601 (MD5) Previous issue date: 2015-08-03 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / An RFID system is typically composed of a reader and a set of tags. An anti-collision algorithm is necessary to avoid collision between tags that respond simultaneously to a reader. The most widely used anti-collision algorithm is DFSA (Dynamic Framed Slotted ALOHA) due to its simplicity and low computational cost. In DFSA algorithms, the optimal TDMA (Time Division Multiple Access) frame size must be equal to the number of unread tags. If the exact number of tags is unknown, the DFSA algorithm needs a tag estimator to get closer to the optimal performance. Currently, applications have required the identification of large numbers of tags, which causes an increase in collisions and hence the degradation in performance of the traditional algorithms DFSA. This work proposes a power control mechanism to estimate the number of tags for radio frequency identification networks (RFID). The mechanism divides the interrogation zone into subgroups of tags and then RSSI (Received Signal Strength Indicator) measurements estimate the number of tags in a subarea. The mechanism is simulated and evaluated using a simulator developed in C/C++ language. In this study, we compare the number of slots and identification time, with ideal DFSA algorithm and Q algorithm EPCglobal standard. Simulation results shows the proposed mechanism provides 99% performance of ideal DFSA in dense networks, where there are many tags. Regarding the Q algorithm, we can see the improvement in performance of 6.5%. It is also important to highlight the lower energy consumption of the reader comparing to ideal DFSA is 63%. / Um sistema de identificação por rádio frequência (RFID) é composto basicamente de um leitor e etiquetas. Para que o processo de identificação das etiquetas seja bem sucedido, é necessário um algoritmo anticolisão a fim de evitar colisões entre etiquetas que respondem simultaneamente à interrogação do leitor. O algoritmo anticolisão mais usado é o DFSA (Dynamic Framed Slotted ALOHA) devido à sua simplicidade e baixo custo computacional. Em algoritmos probabilísticos, tal como o DFSA, o tamanho ótimo do quadro TDMA (Time Division Multiple Access) utilizado para leitura das etiquetas deve ser igual à quantidade de etiquetas não lidas. Uma vez que no processo de leitura, normalmente não se sabe a quantidade exata de etiquetas, o algoritmo DFSA faz uso de um estimador para obter um desempenho mais próximo do ideal. Atualmente, as aplicações têm demandado a identificação de grandes quantidades de etiquetas, o que ocasiona um aumento das colisões e, consequentemente, a degradação no desempenho dos algoritmos DFSA tradicionais. Este trabalho propõe um mecanismo de controle de potência para estimar a quantidade de etiquetas em redes de identificação por rádio frequência (RFID). O mecanismo baseia-se na divisão da área de interrogação em subáreas e, consequentemente, subgrupos de etiquetas. Tal divisão é utilizada para realizar medições de RSSI (Received Signal Strength Indicator) e, assim, estimar a quantidade de etiquetas por subárea. O mecanismo é simulado e avaliado utilizando um simulador próprio desenvolvido em linguagem C/C++. Neste estudo, comparam-se os resultados de quantidade de slots e tempo de identificação das etiquetas, com os obtidos a partir da utilização dos algoritmos DFSA ideal e algoritmo padrão Q da norma EPCglobal. A partir dos resultados da simulação, é possível perceber que o mecanismo proposto apresenta desempenho 99% do DFSA ideal em redes densas, onde há grande quantidade de etiquetas. Em relação ao algoritmo Q, percebe-se a melhoria de 6,5% no desempenho. É importante ressaltar também a redução no consumo de energia do leitor em torno de 63% em relação ao DFSA ideal.