Survey on Mobile WiMAX- Technical Overview

Worldwide Interoperability for Microwave Access (WiMAX), is a wireless communications technology aiming to provide wireless data over long distances in a variety of ways as an alternative to cable and DSL, from point-to-point links to full mobile cellular type access. It is based on the IEEE 802.16 standard.  The goal of this deliverable is to provide an overview of the functionality and a description of the WiMAX network architecture. We also evaluate the special features of the WiMAX technology, such as the improved coverage in Non Line Of Sight (NLOS) environments, in order to examine the applicability of well-known localization techniques. Some of the advanced features such as adaptive antenna systems (AAS) which can significantly improve the performance are discussed. The performance will enable transparency of quality of service (QoS) between Mobile WiMAX and broadband wired services such as Cable and DSL. The scalable architecture, high data throughput and low cost deployment make Mobile WiMAX a leading solution for wireless broadband services. Due to “friendly ecosystem†hundreds of companies have contributed to the development of the technology. Finally, we investigate the characteristics of WiMAX technology

Predicting survival probability for major congestive heart failure events in patients attaining a low peak respiratory exchange ratio during cardiopulmonary exercise testing

Many congestive heart failure (CHF) patients may not be able to attain a peak respiratory exchange ratio (RERpeak) >1.10 during maximal cardiopulmonary exercise (CPX) testing. Although this is usually attributed to a submaximal effort, a portion of this population may not be able to attain this RERpeak level due to pathophysiological complications of heart failure. Currently, little is known about the predictive value of CPX testing in CHF patients with a RERpeak 34, LVEF 1.10) group within the same V.O2peak stratum. Exploratory multivariate proportional hazard analysis in this particular group revealed that no use of beta-blockers, V.E/V.CO2 slope >45, LVEF <25% and ischemic etiology of CHF were the significant independent predictors of CHF-related events

The Needle Component of the Type III Secreton of Shigella Regulates the Activity of the Secretion Apparatus

Gram-negative bacteria commonly interact with eukaryotic host cells by using type III secretion systems (TTSSs or secretons). TTSSs serve to transfer bacterial proteins into host cells. Two translocators, IpaB and IpaC, are first inserted with the aid of IpaD by Shigella into the host cell membrane. Then at least two supplementary effectors of cell invasion, IpaA and IpgD, are transferred into the host cytoplasm. How TTSSs are induced to secrete is unknown, but their activation appears to require direct contact of the external distal tip of the apparatus with the host cell. The extracellular domain of the TTSS is a hollow needle protruding 60 nm beyond the bacterial surface. The monomeric unit of the Shigella flexneri needle, MxiH, forms a superhelical assembly. To probe the role of the needle in the activation of the TTSS for secretion, we examined the structure-function relationship of MxiH by mutagenesis. Most point mutations led to normal needle assembly, but some led to polymerization or possible length control defects. In other mutants, secretion was constitutively turned “on.” In a further set, it was “constitutively on” but experimentally “uninducible.” Finally, upon induction of secretion, some mutants released only the translocators and not the effectors. Most types of mutants were defective in interactions with host cells. Together, these data indicate that the needle directly controls the activity of the TTSS and suggest that it may be used to “sense” host cells

Rhesus macaque model of chronic opiate dependence and neuro-AIDS: longitudinal assessment of auditory brainstem responses and visual evoked potentials

Our work characterizes the effects of opiate (morphine) dependence on auditory brainstem and visual evoked responses in a rhesus macaque model of neuro-AIDS utilizing a chronic continuous drug delivery paradigm. The goal of this study was to clarify whether morphine is protective, or if it exacerbates simian immunodeficiency virus (SIV) related systemic and neurological disease. Our model employs a macrophage tropic CD4/CCR5 co-receptor virus, SIVmac239 (R71/E17), which crosses the blood brain barrier shortly after inoculation and closely mimics the natural disease course of human immunodeficiency virus (HIV) infection. The cohort was divided into 3 groups: morphine only, SIV only, and SIV + morphine. Evoked potential (EP) abnormalities in sub-clinically infected macaques were evident as early as eight weeks post-inoculation. Prolongations in EP latencies were observed in SIV-infected macaques across all modalities. Animals with the highest CSF viral loads and clinical disease showed more abnormalities than those with sub-clinical disease, confirming our previous work (Raymond et al, 1998, 1999, 2000). Although some differences were observed in auditory and visual evoked potentials in morphine treated compared to untreated SIV-infected animals, the effects were relatively small and not consistent across evoked potential type. However, morphine treated animals with subclinical disease had a clear tendency toward higher virus loads in peripheral and CNS tissues (Marcario et al., 2008) suggesting that if had been possible to follow all animals to end-stage disease, a clearer pattern of evoked potential abnormality might have emerged

Expression, purification, crystallization and preliminary crystallographic analysis of MxiH, a subunit of the Shigella flexneri type III secretion system needle

A monodisperse truncation mutant of MxiH, the subunit of the S. flexneri type III secretion system needle, has been crystallized. SeMet derivatives and a uranyl derivative have undergone preliminary crystallographic analysis

IpaD Localizes to the Tip of the Type III Secretion System Needle of Shigella flexneri

This is the publisher's version, also available electronically from http://iai.asm.org/content/74/8/4391Shigella flexneri, the causative agent of shigellosis, is a gram-negative bacterial pathogen that initiates infection by invading cells within the colonic epithelium. Contact with host cell surfaces induces a rapid burst of protein secretion via the Shigella type III secretion system (TTSS). The first proteins secreted are IpaD, IpaB, and IpaC, with IpaB and IpaC being inserted into the host cell membrane to form a pore for translocating late effectors into the target cell cytoplasm. The resulting pathogen-host cross talk results in localized actin polymerization, membrane ruffling, and, ultimately, pathogen entry. IpaD is essential for host cell invasion, but its role in this process is just now coming to light. IpaD is a multifunctional protein that controls the secretion and presentation of IpaB and IpaC at the pathogen-host interface. We show here that antibodies recognizing the surface-exposed N terminus of IpaD neutralize Shigella's ability to promote pore formation in erythrocyte membranes. We further show that MxiH and IpaD colocalize on the bacterial surface. When TTSS needles were sheared from the Shigella surface, IpaD was found at only the needle tips. Consistent with this, IpaD localized to the exposed tips of needles that were still attached to the bacterium. Molecular analyses then showed that the IpaD C terminus is required for this surface localization and function. Furthermore, mutations that prevent IpaD surface localization also eliminate all IpaD-related functions. Thus, this study demonstrates that IpaD localizes to the TTSA needle tip, where it functions to control the secretion and proper insertion of translocators into host cell membrane

IpaD Localizes to the Tip of the Type III Secretion System Needle of Shigella flexneri

This is the publisher's version, also available electronically from http://iai.asm.org/content/74/8/4391Shigella flexneri, the causative agent of shigellosis, is a gram-negative bacterial pathogen that initiates infection by invading cells within the colonic epithelium. Contact with host cell surfaces induces a rapid burst of protein secretion via the Shigella type III secretion system (TTSS). The first proteins secreted are IpaD, IpaB, and IpaC, with IpaB and IpaC being inserted into the host cell membrane to form a pore for translocating late effectors into the target cell cytoplasm. The resulting pathogen-host cross talk results in localized actin polymerization, membrane ruffling, and, ultimately, pathogen entry. IpaD is essential for host cell invasion, but its role in this process is just now coming to light. IpaD is a multifunctional protein that controls the secretion and presentation of IpaB and IpaC at the pathogen-host interface. We show here that antibodies recognizing the surface-exposed N terminus of IpaD neutralize Shigella's ability to promote pore formation in erythrocyte membranes. We further show that MxiH and IpaD colocalize on the bacterial surface. When TTSS needles were sheared from the Shigella surface, IpaD was found at only the needle tips. Consistent with this, IpaD localized to the exposed tips of needles that were still attached to the bacterium. Molecular analyses then showed that the IpaD C terminus is required for this surface localization and function. Furthermore, mutations that prevent IpaD surface localization also eliminate all IpaD-related functions. Thus, this study demonstrates that IpaD localizes to the TTSA needle tip, where it functions to control the secretion and proper insertion of translocators into host cell membrane

Study of Sun Position Tracking Method Based On Path of Sun Using Combine Linear And Rotary Motion Mechanism

Present paper shows the effective utilization of solar energy. Solar energy can be converted into electricity by using PV cell. The efficiency off PV Cells lowers in fixed tilt solar panel. And its efficiency depends on direction off sun rays. to recover the efficiency dual axis sun tracking system use, But disadvantage of this system is, it requires solar mapping which increases cost of system. Also this system I s very bulky, require more space and cannot transfer from one place to another. It can be used in a area where solar mapping is done. And less effective in other area. The proposed sun position tracking mechanism works faster and tracks the position of sun in less time and increases the output from solar panel

The Shigella T3SS needle transmits a signal for MxiC release, which controls secretion of effectors

Type III secretion systems (T3SSs) are key determinants of virulence in many Gram-negative bacteria, including animal and plant pathogens. They inject ‘effector’ proteins through a ‘needle’ protruding from the bacterial surface directly into eukaryotic cells after assembly of a ‘translocator’ pore in the host plasma membrane. Secretion is a tightly regulated process, which is blocked until physical contact with a host cell takes place. Host cell sensing occurs through a distal needle ‘tip complex’ and translocators are secreted before effectors. MxiC, a Shigella T3SS substrate, prevents premature effector secretion. Here, we examine how the different parts of T3SSs work together to allow orderly secretion. We show that T3SS assembly and needle tip composition are not altered in an mxiC mutant. We find that MxiC not only represses effector secretion but that it is also required for translocator release. We provide genetic evidence that MxiC acts downstream of the tip complex and then the needle during secretion activation. Finally, we show that the needle controls MxiC release. Therefore, for the first time, our data allow us to propose a model of secretion activation that goes from the tip complex to cytoplasmic MxiC via the needle