Spirochetal Lipoproteins and Immune Evasion.

Spirochetes are a major threat to public health. However, the exact pathogenesis of spirochetal diseases remains unclear. Spirochetes express lipoproteins that often determine the cross talk between the host and spirochetes. Lipoproteins are pro-inflammatory, modulatory of immune responses, and enable the spirochetes to evade the immune system. In this article, we review the modulatory effects of spirochetal lipoproteins related to immune evasion. Understanding lipoprotein-induced immunomodulation will aid in elucidating innate pathogenesis processes and subsequent adaptive mechanisms potentially relevant to spirochetal disease vaccine development and treatment

Moving Toward Police Accountability: Beyond Senate Bill 2

On September 30, 2021, California Governor Gavin Newsom signed into law Senate Bill 2 (SB 2), “creat[ing] a system to investigate and revoke or suspend peace officer certification for serious misconduct,” as well as establishing the Peace Officer Standards Accountability Division and the Peace Standards Accountability Advisory Board, which will be responsible for investigations into police misconduct. This Note will describe the new features of SB 2’s decertification provisions in contrast to traditional methods of addressing police misconduct. Additionally, this Note will examine where the bill fell short, and how to overcome its shortcomings

Oxidative cracking of n-Hexane : a catalytic pathway to olefins

Steam cracking, the major, current existing route for light olefin production, is the most energy consuming process in the chemical industry. The need for an energy efficient processes, urged substantial research work for the development of new catalytic technologies for light olefin production. Steam cracking maximizes ethylene formation and propylene is produced only as a secondary product. The faster increase in demand of propylene than that of ethylene makes steam cracking a less attractive route for the production of propylene. Thus, catalytic pathways that provide for more propylene formation are essential. The present thesis investigates catalytic pathways for n‐hexane cracking, as a model\ud compound of naphtha, in the presence of oxygen. Compared to steam cracking, this work aims towards achieving; (i) lower cracking temperatures making the overall process less energy consuming and (ii) higher selectivities to both propylene and butylenes

Dependence of the average spatial and energy characteristics of the hadron-lepton cascade on the strong interaction parameters at superhigh energies

A method for calculating the average spatial and energy characteristics of hadron-lepton cascades in the atmosphere is described. The results of calculations for various strong interaction models of primary protons and nuclei are presented. The sensitivity of the experimentally observed extensive air showers (EAS) characteristics to variations of the elementary act parameters is analyzed

COMPLEX THEORY AND METHODS IN INTERNATIONAL RELATIONS

This article presents the emergence of complexity theory in sciences and in the field of International Relations (IR). The first part shows that the emergence of what is called the IR fifth debate finds its roots in an already old questioning and, hence, makes possible to clarify the notion of complexity. The second part shows how the transdisciplinary methodologies of complex systems are implemented in different issues related to International Relations. Finally, the interest of the approach and the perspectives opened up by the theory and the method of complex systems are discussed.&nbsp

Conception d’un dispositif de camouflage microfluidique

Depuis la réalisation d’un camouflage optique en 2006, le concept de masquer la présence d’un objet au regard d’une certaine grandeur physique s’est répandu dans tous les domaines de la physique. De nombreuses équipes se sont alors donné pour objectif de faire en sorte qu’un trou dans un milieu 2D ne soit pas détectable en mesurant un champ physique donné loin de celui-ci. La majorité de ces camouflages se sont appuyés sur des matériaux entièrement structurés par l’homme afin de présenter des propriétés inobservées dans la nature, appelés "métamatériaux". Bien que de nombreux camouflages physiques aient été réalisés grâce à ceux-ci, à ce jour aucun d’entre eux ne peut dissimuler un objet à la fois d’un écoulement (i.e. en pression et en vitesse) et de transport chimique ou thermique (i.e. en concentration ou température). Cela serait pourtant très utile en génie biomédical, et plus particulièrement dans le domaine des biocapteurs, où des surfaces sensibles sont placées dans un écoulement microfluidique incident chargé en espèces chimiques, incluant des parasites. Un problème récurrent des biocapteurs est l’adsorption non spécifique de ces parasites dans les liaisons entre éléments biologiques et surfaces physiques, qui réduit la spécificité, la sensibilité et la reproductibilité des mesures. Un camouflage microfluidique d’écoulement et de transport permettrait de protéger les surfaces sensibles de ce phénomène, tout en éliminant l’influence croisée que les surfaces voisines ont les unes sur les autres dans les études multiplexées. Le travail présenté ici consiste à concevoir un tel dispositif de camouflage microfluidique. Dans le cadre des biocapteurs, il faut que le camouflage puisse être interrompu au moment oppor-tun, qui correspond typiquement au ratio maximal entre les concentrations d’analytes et de parasites, puis réactivé après mesures. Même si au prix d’une grande complexité structurelle certains métamatériaux disposent de propriétés physiques modifiables, la zone camouflée reste quant à elle figée. Par conséquent, on doit trouver une stratégie de dissimulation n’impliquant pas de métamatériaux solides. On choisit ici de se baser sur une réinterprétation microflui-dique du "paradoxe de d’Alembert", inspirée par des analogies fortes avec les camouflages optiques. Tout d’abord, un cadre théorique est donné à cette stratégie impliquant des obstacles flui-diques appelés "corps de Rankine". On justifie puis développe des modèles d’écoulements potentiels pour décrire leur contour. On trouve alors que le système est théoriquement apte à camoufler un obstacle en termes de champ de vitesses. Ensuite, on prend en compte les e˙ets visqueux pour trouver la relation entre la taille de l’obstacle et la chute de pression dans le système, qui s’avère être d’ordre 2 et permet donc un camouflage en pression eÿcace pour des obstacles suÿsamment petits. Une fois le camouflage caractérisé mécaniquement, on propose un modèle analytique pour les échanges d’espèces et de chaleur s’y produisant. Cependant, ce modèle ne permet pas de conclure sur le camouflage en concentration ou en température loin en aval. Pour faire un pas vers le dimensionnement expérimental du camouflage, on passe à l’outil numérique en réalisant des simulations par éléments finis. Celles-ci révèlent l’influence qu’ont les di˙érents paramètres du système sur l’allure du camouflage, et donnent une première idée de la contrôlabilité du système. Certains résultats numériques permettent alors de condition-ner le camouflage chimique au caractère convectif de l’écoulement, associé à un haut nombre de Péclet. Une fois combinées à la théorie, ces simulations produisent un jeu de paramètres permettant l’implémentation expérimentale d’un dispositif de camouflage. Plusieurs designs sont alors fabriqués et testés, jusqu’à parvenir à une version stable et eÿcace réalisée par impression 3D. L’écoulement et le transport dans ce dispositif sont alors évalués expérimentalement et com-parés aux résultats théoriques, qui sont en très bon accord. Plus précisément, on montre que l’on dispose d’un contrôle précis sur la forme de l’interface du camouflage ainsi que sur les échanges chimiques ou thermiques y ayant lieu. On prouve aussi que le camouflage peut être modifié, activé ou désactivé en quelques dizaines de secondes. On démontre ensuite qu’il peut servir de filtre en géométrie "ouverte", et obéit aux mêmes lois d’échelles que les autres filtres microfluidiques classiques. Pour finir, on valide que ce camouflage peut e˙ectivement protéger une surface de l’adsorption d’une espèce indésirable dans un écoulement pendant de longues périodes de temps. Un tel camouflage microfluidique peut donc fortement contribuer au génie biomédical en rendant les biocapteurs moins vulnérables à l’adsorption non spécifique, mais dépasse aussi ce cadre puisqu’il peut fonctionner avec n’importe quelle surface sensible, comme un tapis cellulaire ou des tranches de tissu. De plus, ce dispositif constitue un apport intéressant au secteur de la microfluidique "ouverte", dont il est à ce jour le seul filtre connu. Enfin, il présente un fort attrait en physique de par sa contribution au domaine florissant des camouflages, en proposant une stratégie inédite de dissimulation pour les grandeurs d’écoulement et de transport.----------ABSTRACT Since the realization of an optical cloak in 2006, the idea of hiding the presence of an object with respect to a certain physical measure has spread to every field of physics. Many have tried before to make a hole in a 2D medium that could not be detected by measuring a given physical field afar. Most of these cloaks relied on materials entirely man-made to exhibit properties not observed in nature, called "metamaterials". Although many physical cloaks have been obtained using such materials, to date none of them can conceal an object from both flow (i.e. pressure and velocity) and chemical or thermal transport (i.e. concentration or temperature). However, this would be very useful in biomedical engineering, especially in the field of biosensors, where sensitive surfaces are placed within an incident microfluidic flow loaded with chemical species, including parasites. A recurring biosensors problem is the non-specific adsorption of these parasites in the bonds between biological elements and the physical surface, which reduces the specificity, sensitivity and reproducibility of the measurements. A microfluidic flow and transport cloak would protect sensitive surfaces from this phenomenon, while eliminating the cross-influence that neighboring surfaces have on each other in multiplexed studies. The work presented here consists in designing such a microfluidic cloaking device. In the context of biosensors, the cloak must be able to be deactivated at the appropriate time, which typically corresponds to the maximum ratio between analyte and parasite concentrations, and then reactivated after measurements. Even if at the cost of high structural complexity some metamaterials have modifiable physical properties, the concealed area remains fixed. Therefore, a cloaking strategy that does not involve solid metamaterials must be found. We choose here to rely on a microfluidic reinterpretation of the "d’Alembert’s paradox", inspired by strong analogies with optical cloaking. First of all, a theoretical framework is given to this strategy involving fluidic obstacles called "Rankine bodies". We justify the use and develop potential flow models to describe their contours. It is then found that the system is theoretically capable of cloaking an obstacle in terms of velocity field. Then, the viscous e˙ects are taken into account to find the relationship between the size of the obstacle and the pressure drop in the system, which turns out to be a second order power law and thus allows an e˙ective pressure cloak for suÿciently small impediments. Once the cloak is mechanically characterized, an analytical model is proposed to describe the species and heat exchanges occurring within it. However, this model does not allow a firm conclusion about concentration (or temperature) cloaking far downstream.To take a step towards realizing the cloak experimentally, we switch to the numerical tool by carrying out finite element simulations. These reveal the influence of the various system parameters on the cloak shape and give us a first glance at the controllability of the system. Some of these numerical results can be used to condition the chemical cloaking eÿciency to the convective aspect of the flow, associated with a high Péclet number. Once combined with the theory, these simulations produce a set of parameters allowing the experimental implementation of a cloaking device. Several designs are then manufactured and tested, until a stable and eÿcient version is produced by 3D printing. Flow and transport in this device are then experimentally investigated and compared to the theoretical results, which are in very good agreement. Specifically, it is shown that one has a precise control over the shape of the cloak interface as well as the chemical or thermal exchanges taking place in it. It is also shown that the cloak can be modified, activated or deactivated in a few tens of seconds. It is then demonstrated that it can be used as a filter in an "open-space" geometry and obeys the same scaling laws as other conventional microfluidic filters. Finally, we validate that this cloak can e˙ectively protect a surface adsorption in an undesirable species flow for long periods of time. Such microfluidic cloak can therefore make a significant contribution to biomedical engineer-ing by making biosensors less vulnerable to non-specific adsorption, but its applications also go beyond this field since the cloak can work with any sensitive surface, such as a cell layers or slices of tissue. Moreover, this device is an interesting contribution to the "open" microfluidics sector, of which it is to date the only known filter. Finally, it has a strong appeal in physics due to its contribution to the flourishing field of cloaking, by proposing a novel concealment strategy for flow and transport quantities

Oxidative Conversion of Hexane to Olefins-Influence of Plasma and Catalyst on Reaction Pathways

An integrated plasma-Li/MgO system is efficient for the oxidative conversion of hexane. In comparison to the Li/MgO catalytic system, it brings considerable improvements in the yields of light olefins (C 2 = –C 5 = ) at relatively low temperatures indicating synergy from combination of plasma and catalyst. The study on the influence of temperature on the performance of the integrated plasma-Li/MgO system shows dominancy of plasma chemistry at the lower temperature (500°C), while contribution from the catalyst both in hexane activation and in enhancing olefin formation becomes significant at the higher temperature (600°C). At 500°C significant amount of acetylene formation is observed. This is minimized at 600°C at oxygen depleting condition

Hidad

"Nadia Seboussi's work takes up the question of armed conflict and what it gives rise to : violence, migration and exile. The works assembled for this publication focus on the representation of the Algerian tragedy by the recreation in video tableaux of these now-mythical depictions." -- Back cover

Contamination control engineering design guidelines for the aerospace community

Thermal control surfaces, solar arrays, and optical devices may be adversely affected by a small quantity of molecular and/or particulate contamination. What is rarely discussed is how one: (1) quantifies the level of contamination that must be maintained in order for the system to function properly, and (2) enforces contamination control to ensure compliance with requirements. This document is designed to address these specific issues and is intended to serve as a handbook on contamination control for the reader, illustrating process and methodology while providing direction to more detailed references when needed. The effects of molecular contamination on reflecting and transmitting surfaces are examined and quantified in accordance with MIL STD 1246C. The generation, transportation, and deposition of molecular contamination is reviewed and specific examples are worked to illustrate the process a design engineer can use to estimate end of life cleanliness levels required by solar arrays, thermal control surfaces, and optical surfaces. A similar process is used to describe the effect of particulate contamination as related to percent area coverage (PAC) and bi-directional reflectance distribution function (BRDF). Relationships between PAC and surface cleanliness, which include the effects of submicron sized particles, are developed and BRDF is related to specific sensor design parameters such as Point Source Transmittance (PST). The pros and cons of various methods of preventing, monitoring, and cleaning surfaces are examined and discussed