32 research outputs found

    Performance analysis on percentage of wheel slip for a passenger car using GPS and wheel speed sensor

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    This thesis deals with the analysis on percentage of wheel slip for a passenger car using GPS and wheel speed sensor. The objective of this thesis is to analyze the percentage of wheel slip for a passenger car in a various velocity, road condition and driving mode. The thesis describes the post-processing method to analyze the percentage of wheel slip and identify the effective rolling radius and the longitudinal tire stiffness for maximum tire life and performance. Driving and braking behaviour of vehicle were both studied in this thesis for paved and unpaved sandy road condition which commonly the contributing factors to the wheel slip to occur. The data used for the analysis is obtained through experimental test using UMP Test Car which has been installed with Wheel Pulse Transducer, Global Positioning System and DEWESOFT software for data acquisition purpose. The post-processing method was performed using Flexpro and Microsoft Office Excel. The post-processing method to analyze the percentage of wheel slip was performed using the SAE definition of wheel slip and the percent error in the distance travel by the car between free rolling and actual condition. Finally, the longitudinal force, the effective rolling radius and the longitudinal tire stiffness was determined for both driving and braking maneuver of vehicle on paved and unpaved sandy road condition. From the results, it is observed that the percentage of wheel slip during driving maneuver is higher for unpaved sandy road condition compares to that the paved road. It is also observed that the longitudinal force of the tire is lower for unpaved sandy road compare to the paved road condition. The effective rolling radius of the tire during driving maneuver was determined to be lower compare to the free rolling radius of the tire. During braking manuever, the results show that the percentage of wheel slip is higher for unpaved sandy road compare to that for paved road condition. The longitudinal force and tire stiffness also observed lower for unpaved sandy road condition. The effective rolling radius of the tire during braking determined higher compared to that in the free rolling radius. The results concluded that the percentage of wheel slip is strongly dependent to the longitudinal force and the tire road friction. Therefore, effective rolling radius and longitudinal tire stiffness obtained can significantly use to improve tire design and construction. The results also can be use to improve the energy usage efficiency and fuel consumption of vehicle

    Langostas, plagas de ayer y de hoy

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    Los acrídidos (Acrididae), conocidos como langostas, tucuras, saltamontes, son una familia de insectos ortópteros. Los representantes de este grupo, son insectos predominantemente alados, saltadores, de tamaño mediano a grande, con aparatos bucales masticadores que se alimentan de vegetales, en su gran mayoría.EEA ReconquistaFil: Vitti Scarel, Daniela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista; ArgentinaFil: Szwarc, Diego Ernesto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista; ArgentinaFil: Parodi, Maria Ines. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista. Agencia de Extensión Rural Tostado; ArgentinaFil: Colombo, Facundo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista. Agencia de Extensión Rural Tostado; ArgentinaFil: Leonhardt, María Ofelia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista. Agencia de Extensión Rural Tostado; ArgentinaFil: Fernández, Analía. Servicio Nacional de Sanidad y Calidad Agroalimentaria; Argentin

    Metabolic profiling of Arabidopsis thaliana epidermal cells

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    Metabolic phenotyping at cellular resolution may be considered one of the challenges in current plant physiology. A method is described which enables the cell type-specific metabolic analysis of epidermal cell types in Arabidopsis thaliana pavement, basal, and trichome cells. To achieve the required high spatial resolution, single cell sampling using microcapillaries was combined with routine gas chromatography-time of flight-mass spectrometry (GC-TOF-MS) based metabolite profiling. The identification and relative quantification of 117 mostly primary metabolites has been demonstrated. The majority, namely 90 compounds, were accessible without analytical background correction. Analyses were performed using cell type-specific pools of 200 microsampled individual cells. Moreover, among these identified metabolites, 38 exhibited differential pool sizes in trichomes, basal or pavement cells. The application of an independent component analysis confirmed the cell type-specific metabolic phenotypes. Significant pool size changes between individual cells were detectable within several classes of metabolites, namely amino acids, fatty acids and alcohols, alkanes, lipids, N-compounds, organic acids and polyhydroxy acids, polyols, sugars, sugar conjugates and phenylpropanoids. It is demonstrated here that the combination of microsampling and GC-MS based metabolite profiling provides a method to investigate the cellular metabolism of fully differentiated plant cell types in vivo

    Impact of the fungal quorum sensing molecule farnesol on human innate immune cells

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    Quorum sensing (QS) is a cell density-dependent mechanism that affects microbial metabolism and gene expression. In fungi, the QS phenomenon has first been described for the opportunistic pathogen C. albicans, which produces farnesol as a QS molecule to regulate virulence determinants. Aside from controlling morphogenesis, the impact of farnesol throughout the infection process has been only partially elucidated. The aim of this study was to unravel the impact of farnesol on innate immune cells important for fungal clearance and protective immune response. Therefore, neutrophils, monocytes and dendritic cells (DC) were investigated concerning phenotype and effector mechanisms. Farnesol activated neutrophils and monocytes, reflected in an enhanced expression of activation markers on the surface of both immune cells and in an increased release of proteolytic enzymes by neutrophils and pro-inflammatory cytokines by monocytes. This low-grade activation was not sufficient to influence fungicidal activity of neutrophils and monocytes towards C. albicans. The greatest impact of farnesol was found on the differentiation process of human monocytes into mature DC. Substantial changes were observed to the differentiation phenotype characterized by reduced expression of markers important for maturation and antigen presentation. Furthermore, farnesol influenced the release of a variety of inflammatory cytokines and chemokines, wherein the secretion of Th1-inducing cytokines such as IL 12 were markedly reduced. Limitations in mobility and a reduced T cell stimulatory capacity of DC generated in the presence of farnesol were ascertained and suggest an immunomodulatory function of farnesol. Altogether, this study promotes the ability of farnesol to act as a virulence factor of C. albicans by influencing innate immune cells to promote inflammation and dampening the Th1 response which is essential for fungal clearance

    Host response to Candida albicans bloodstream infection and sepsis

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    Candida albicans is a major cause of bloodstream infection which may present as sepsis and septic shock - major causes of morbidity and mortality world-wide. After invasion of the pathogen, innate mechanisms govern the early response. Here, we outline the models used to study these mechanisms and summarize our current understanding of innate immune responses during Candida bloodstream infection. This includes protective immunity as well as harmful responses resulting in Candida induced sepsis. Neutrophilic granulocytes are considered principal effector cells conferring protection and recognize C. albicans mainly via complement receptor 3. They possess a range of effector mechanisms, contributing to elimination of the pathogen. Neutrophil activation is closely linked to complement and modulated by activated mononuclear cells. A thorough understanding of these mechanisms will help in creating an individualized approach to patients suffering from systemic candidiasis and aid in optimizing clinical management

    Preschool development of very low birth weight children born 1994–1995

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    Hanke C, Lohaus A, Gawrilow C, Hartke I, Köhler B, Leonhardt A. Preschool development of very low birth weight children born 1994–1995. European Journal of Pediatrics. 2003;162(3):159-164

    Case report: Febrile infection-related epilepsy syndrome in a 14-year-old girl with multiple organ failure and lethal outcome

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    We report a case of an otherwise healthy 14-year-old girl with febrile infection-related epilepsy syndrome (FIRES), multiple organ failure (MOF), and ultimately a lethal outcome. This is a rare case of FIRES with MOF and consecutive death. Only a few cases have been described in the literature. The adolescent girl was initially admitted to our pediatric emergency department with a first episode of generalized tonic–clonic seizures after a short history of fever a week before admission. Seizures progressed rapidly into refractory status epilepticus without any evidence of the underlying cause, and treatment subsequently had to be escalated to thiopental anesthesia. Since the initial diagnostics showed no promising leads, the rare syndrome of FIRES was suspected, representing a catastrophic epileptic encephalopathy linked to a prior benign febrile infection. Methylprednisolone, intravenous immunoglobulins, and a ketogenic diet were initiated. Respiratory, circulatory, kidney, and liver failure developed during treatment, requiring increasing intensive care. Multiple attempts to deescalate antiepileptic treatment resulted in recurrent status epilepticus. A cranial MRI on the 10th day of treatment revealed diffuse brain edema and no cerebral perfusion. The patient was declared dead on the 11th day of treatment. FIRES should be taken into account in previously healthy children with a new onset of difficult-to-treat seizures after a short febrile infection when no other cause is apparent. First-line treatment, besides seizure control, is the early initiation of immunomodulatory therapy and the start of a ketogenic diet. As treatment is difficult and MOF may develop, patients should be transferred to a specialized children’s hospital providing full intensive care

    Krüppel-like Factor 4 modulates interleukin-6 release in human dendritic cells after in vitro stimulation with Aspergillus fumigatus and Candida albicans

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    Invasive fungal infections are associated with high mortality rates and are mostly caused by the opportunistic fungi Aspergillus fumigatus and Candida albicans. Immune responses against these fungi are still not fully understood. Dendritic cells (DCs) are crucial players in initiating innate and adaptive immune responses against fungal infections. The immunomodulatory effects of fungi were compared to the bacterial stimulus LPS to determine key players in the immune response to fungal infections. A genome wide study of the gene regulation of human monocyte-derived dendritic cells (DCs) confronted with A. fumigatus, C. albicans or LPS was performed and Krüppel-like factor 4 (KLF4) was identified as the only transcription factor that was down-regulated in DCs by both fungi but induced by stimulation with LPS. Downstream analysis demonstrated the influence of KLF4 on the interleukine-6 expression in human DCs. Furthermore, KLF4 regulation was shown to be dependent on pattern recognition receptor ligation. Therefore KLF4 was identified as a controlling element in the IL-6 immune response with a unique expression pattern comparing fungal and LPS stimulation
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