1,720,985 research outputs found
Producción y marcado fluorescente de los factores de iniciación IF1 e IF3 de Mycobacterium tuberculosis
Full text linkSi bien la fase de iniciación de la síntesis de proteínas ha sido extensivamente caracterizada usando unos pocos organismos modelo, pocos estudios han estudiado directamente este proceso en el patógeno M. tuberculosis, sus ribosomas o factores de iniciación. Por ello, en este trabajo se produjeron y marcaron con fluorescencia los factores de iniciación IF1 e IF3 nativos y mutantes de M. tuberculosis, para posteriormente poder estudiar su papel en la iniciación de la traducción de M. tuberculosis. Células competentes de E. coli BL21 fueron
transformadas con los plásmidos correspondientes a las proteínas Mtb-IF1, Mtb-IF1D5C, Mtb-IF3 e Mtb-IF3D157C. Después, se produjeron las proteínas obteniendo eficiencias de purificación de 0.78 mg/L para Mtb-IF1 con una pureza del 87 %, de 0.375 mg/L para Mtb-IF1D5C con una pureza del 99 %, de 1.6 mg/L para Mtb-IF3 con una pureza del 80 % y de 0.57 mg/L para Mtb-IF3D157C con una pureza del 94 %. Las proteínas Mtb-IF1D5C y Mtb-IF3D157C se marcaron con el fluoróforo Atto540Q obteniendo eficiencias de marcado del 62 % y del 74% respectivamente; estas proteínas también se marcaron con el fluoróforo
Alexa488 obteniendo eficiencias de marcado del 50 % y 59 % respectivamente. Finalmente, se evaluó la asociación de los factores de iniciación marcados Mtb-IF1D5C y Mtb-IF3D157C a la subunidad 30S de E. coli usando un sistema heterólogo. Se determinó que ambos factores logran asociarse a la subunidad 30S de E. coli, con mayor afinidad y en el mismo sitio de unión al 30S que sus homólogos de E. coliSubmitted by Ernesto Rojas ([email protected]) on 2024-05-02T18:25:14Z
No. of bitstreams: 1
T030_70689431_T ANCHORENA OLIVARI, MARIO ANDRÉ.pdf: 4491883 bytes, checksum: 7ebd2942f2ee1b667f816e6d0339a204 (MD5)Made available in DSpace on 2024-05-02T18:25:14Z (GMT). No. of bitstreams: 1
T030_70689431_T ANCHORENA OLIVARI, MARIO ANDRÉ.pdf: 4491883 bytes, checksum: 7ebd2942f2ee1b667f816e6d0339a204 (MD5)
Previous issue date: 2023Tesi
La regolazione a rotatoria delle intersezioni stradali
No full textIl volume si pone come finalità generale di fornire al lettore le basi teoriche e gli strumenti operativi per affrontare le principali problematiche connesse con la regolazione delle inter-sezioni stradali a raso attraverso l’uso delle rotatorie.
Lo studio fornisce in modo sufficientemente ampio la descrizione delle tematiche legate alle moderne rotatorie: da una esposizione generale del dispositivo di moderazione del traffico alle principali metodologie di calcolo della capacità degli ingressi in uso nei paesi occiden-tali (Europa, Stati Uniti e Australia), confrontando e integrando, in qualche caso con risultati di ricerche specifiche, le formule di capacità di derivazione sperimentale e quelle derivate dalla logica gap acceptance.
Il testo dedica uno spazio particolare alle rotatorie innovative, note come turborotatorie, nonché a un aspetto sinora poco approfondito, quello degli apprestamenti per gli utenti non motorizzati, pedoni e ciclisti. Lo studio è completato, infine, da un’analisi dei più interes-santi aspetti della geometria dell’intersezione, seguendo e interpretando anche in modo in-novativo le linee guida della Federal highway administration.
L’opera, derivata dall’esperienza didattica, di ricerca e professionale degli autori, è mirata alla formazione dell’ingegnere trasportista, ma costituisce, anche, un supporto utile per spe-cifiche ricerche della materia
Il sistema di Trasporto Personale Automatico per le città del XXI Secolo
No full textLa centralità assunta dalle aree metropolitane nel processo di crescita dei territori su di esse gravitanti ha determinato un crescente infittirsi delle relazioni tra coloro che in esse vivono, lavorano, soddisfano le proprie esigenze culturali e i propri bisogni di socialità. Per questo motivo, uno dei banchi di prova su cui tali aree si devono misurare sta nella capacità di soddisfare quote sempre maggiori di domanda attraverso un assetto del trasporto sostenibile ed efficiente. Il personal rapid transit, sistema di trasporto personalizzato, automatico e sostenibile che, sebbene da decenni al centro dell’interesse tecnico-scientifico della materia può contare solo su pochissime realizzazioni al mondo, potrebbe tornare attuale rappresentando una formidabile risposta alle odierne esigenze urbane di mobilità: in altri termini potrebbe divenire, nel percorso di innovazione dell’offerta pubblica, il naturale anello di raccordo tra i mezzi collettivi tradizionali e i nuovi sistemi cibernetici stradali. Gli autori, dopo aver inserito il PRT all’interno di tale percorso evolutivo, ne hanno descritto le realizzazioni esistenti e quelle in progetto e hanno approfondito le caratteristiche costruttive e di esercizio dei suoi principali elementi costitutivi: il veicolo, l’infrastruttura e le stazioni
Pilot Adaptation to Different Classes of Haptic Aids in Tracking Tasks
No full textHaptic aids have been largely used in manual control tasks to complement the visual information through the sense of touch. To analytically design a haptic aid, adequate knowledge is needed about how pilots adapt their visual response and the biomechanical properties of their arm (i.e., admittance) to a generic haptic aid. In this work, two different haptic aids, a direct haptic aid and an indirect haptic aid, are designed for a target tracking task, with the aim of investigating the pilot response to these aids. The direct haptic aid provides forces on the control device that suggest the right control action to the pilot, whereas the indirect haptic aid provides forces opposite in sign with respect to the direct haptic aid. The direct haptic aid and the indirect haptic aid were tested in an experimental setup with nonpilot participants and compared to a condition without haptic support. It was found that control performance improved with haptic aids. Participants significantly adapted both their admittance and visual response to fully exploit the haptic aids. They were more compliant with the direct haptic aid force, whereas they showed stiffer neuromuscular settings with the indirect haptic aid, as this approach required opposing the haptic forces
Identifying time-varying neuromuscular system with a recursive least-squares algorithm: a Monte-Carlo simulation study
No full textA human-centered design of haptic aids aims at tuning the force feedback based on the effect it has on human behavior. For this goal, a better understanding of the influence of haptic aids on the pilot neuromuscular response becomes crucial. In realistic scenarios, the neuromuscular response can continuously vary depending on many factors, such as environmental factors or pilot fatigue. This paper presents a method that online estimates time-varying neuromuscular dynamics during force-related tasks. This method is based on a Recursive Least Squares (RLS) algorithm and assumes that the neuromuscular response can be approximated by a Finite Impulse Response filter. The reliability and the robustness of the method were investigated by performing a set of Monte-Carlo simulations with increasing level or remnant noise. Even with high level of remnant noise, the RLS algorithm provided accurate estimates when the neuromuscular dynamics were constant or changed slowly. With instantaneous changes, the RLS algorithm needed almost 8s to converge to a reliable estimate. These results seem to indicate that RLS algorithm is a valid tool for estimating online time-varying admittance
An experimental comparison of haptic and automated pilot support systems
No full textExternal aids are required to increase safety and performance during the manual control of an aircraft. Automated systems allow to surpass the performance usually achieved by pilots. However, they suffer from several issues caused by pilot unawareness of the control command from the automation. Haptic aids can overcome these issues by showing their control command through forces on the control device. To investigate how the transparency of the haptic control action in flences performance and pilot behavior, a quantitative comparison between haptic aids and automation is needed. An experiment was conducted in which pilots performed a compensatory tracking task with haptic aids and with automation. The haptic aid and the automation were designed to be equivalent when the pilot was out-of-the-loop, i.e., to provide the same control command. Pilot performance and control effort were then evaluated with pilots in-the-loop and contrasted to a baseline condition without external aids. The haptic system allowed pilots to improve performance compared with the baseline condition. However, automation outperformed the other two conditions. Pilots control effort was reduced by the haptic aid and the automation in a similar way. In addition, the pilot open-loop response was estimated with a non-parametric estimation method. Changes in the pilot response were observed in terms of increased crossover frequency with automation, and decreased neuromuscular peak with haptics
Development of a 6 DOF nonlinear model for the MPI cybermotion simulator
No full textThis paper describes the different phases of realizing and validating a helicopter model for the MPI CyberMotion Simulator (CMS). The considered helicopter is a UH-60 Black Hawk. The helicopter model was developed based on equations and parameters available in literature. First, the validity of the model was assessed by performing tests based on ADS-33E-PRF criteria using closed loop controllers and with a non-expert pilot. Results on simulated data were similar to results obtained with the real helicopter. Second, the validity of the model was assessed with a helicopter pilot in-the-loop in both a fixed-base simulator and the CMS. The pilot performed a vertical remask maneuver defined in ADS-33E-PRF. Most metrics for performance were reached adequately with both simulators. The motion cues in the CMS allowed for improvements in some of the metrics. The pilot was also asked to give a subjective evaluation of the model by answering the Israel Aircraft Industries Pilot Rating Scale (IAI PRS). Similarly to results of ADS-33E-PRF, pilot responses confirmed that the motion cues provided more realistic flight experience
Quasi-transfer of helicopter training from fixed-to motion-base simulator
No full textThis paper presents the experimental evaluation of a previously developed hover training program, designed for fixed-base helicopter simulators. In particular, it is investigated whether the skills developed on the fixed-base simulator are transferred to a highly realistic simulator (quasi-Transfer-of-Training experiment). The higher realism was achieved by using the motion-base MPI CyberMotion Simulator. Student pilots participants were asked to perform the hover maneuver controlling an identified model of a Robinson R44 civil light helicopter. Results showed that the skills acquired during fixed-base training were successfully transferred to the highly-realistic condition. The additional motion feedback helped participants achieve better levels of performance
- …
