Securing multi-tenancy systems through multi DB instances and multiple databases on different physical servers

Use of the same application by multiple users through internet as a service is supported by cloud computing system. Both the user and attacker stay in the same machine as both of them are users of the same application creating an in-secure environment. Service must ensure secrecy both at the application and data layer level. Data isolation and Application isolation are two basic aspects that must be ensured to cater for security as desired by the clients that accesses the service. In this paper a more secured mechanism has been presented that help ensuring data isolation and security when Multi-tenancy of the users to the same service has been implemented

Ferroelectric Properties and Transmission Response ofPZN-PT Single Crystals for Underwater Communication

Single crystal of Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 (PZN-PT) at the composition of morphotropicphase boundary (MPB) shows a very high electromechanical coupling coefficient, piezoelectriccoefficient, and dielectric constant compared to conventional PZT ceramics. These exceptionalproperties of these single crystals find enormous applications in medical ultrasound imaging andunderwater communication (Sonar). The growth of PZN-PT single crystals has been carried outby bottom-supported flux Bridgman method. There are many growth issues to be addressedduring the process of growth. The grown crystals are oriented and cut along <001> directionwith the crystal dimension of 8 x 6 x 1.5 mm3 for further analysis. The oriented crystals were poledat a rate of 1 kV/mm. The poled crystals have been characterised for dielectric, strain andpiezoelectric values. Further, the poled specimen were tested for transmitting response at variousfrequencies in acoustic test facility and the difficulties in their growth

Clinical Use and Therapeutic Potential of IVIG/SCIG, Plasma-Derived IgA or IgM, and Other Alternative Immunoglobulin Preparations

Intravenous and subcutaneous immunoglobulin preparations, consisting of IgG class antibodies, are increasingly used to treat a broad range of pathological conditions, including humoral immune deficiencies, as well as acute and chronic inflammatory or autoimmune disorders. A plethora of Fab- or Fc-mediated immune regulatory mechanisms has been described that might act separately or in concert, depending on pathogenesis or stage of clinical condition. Attempts have been undertaken to improve the efficacy of polyclonal IgG preparations, including the identification of relevant subfractions, mild chemical modification of molecules, or modification of carbohydrate side chains. Furthermore, plasma-derived IgA or IgM preparations may exhibit characteristics that might be exploited therapeutically. The need for improved treatment strategies without increase in plasma demand is a goal and might be achieved by more optimal use of plasma-derived proteins, including the IgA and the IgM fractions. This article provides an overview on the current knowledge and future strategies to improve the efficacy of regular IgG preparations and discusses the potential of human plasma-derived IgA, IgM, and preparations composed of mixtures of IgG, IgA, and IgM

The relationship of LFPs, MUA, and SUA to the bold fMRI signal

The contribution of fMRI to our understanding of the functional anatomy of the brain is directly related to the degree to which the relationship between the MRI signal and the underlying neural activity is understood. It is established that activity in the brain is characterized by time-varying spatial distributions of action potentials superimposed on relatively slow-varying field potentials. To study how such potentials relate to the BOLD signal we scanned the visual cortex of anesthetized monkeys in a 4.7T scanner while recording local field potentials (LFPs), single (SUA), and multi (MUA) unit activity, by means of a novel, recently-developed recording technique. The geometry of novel electrodes and the active compensation built into the recording system minimized magnetic and electrostatic coupling respectively, permitting the elimination of any interference in subsequent off-line analysis. In each session, active sites were selected by first imaging the entire brain with a multi-shot, multi-slice gradient-recalled EPI MRI sequence (TE=20ms, TR=750ms), with FOV=128x128mm^2,128^2 matrix, 2mm thickness. Single slices, with areas of interest, were subsequently imaged with quadrature, transmit/receive volume or implanted surface coils with a voxel size of 250x250x660um^3 using time-resolved MR imaging (TE=20ms, TR=250ms). Our results provide insights into (a) the relationship of slow waves, single unit activity, and coherence functions of simultaneously-recorded single-units to the BOLD signal; (b) the temporal response function of the signals, and (c) the effects of anesthesia depth and stimulus strength on the modulation of each signal-type

Neurophysiological investigation of the basis of the fMRI signal

Functional magnetic resonance imaging (fMRI) is widely used to study the operational organization of the human brain, but the exact relationship between the measured fMRI signal and the underlying neural activity is unclear. Here we present simultaneous intracortical recordings of neural signals and fMRI responses. We compared local field potentials (LFPs), single- and multi-unit spiking activity with highly spatio-temporally resolved blood-oxygen-level-dependent (BOLD) fMRI responses from the visual cortex of monkeys. The largest magnitude changes were observed in LFPs, which at recording sites characterized by transient responses were the only signal that significantly correlated with the haemodynamic response. Linear systems analysis on a trial-by-trial basis showed that the impulse response of the neurovascular system is both animal- and site-specific, and that LFPs yield a better estimate of BOLD responses than the multi-unit responses. These findings suggest that the BOLD contrast mechanism reflects the input and intracortical processing of a given area rather than its spiking output

In vivo study of connectivity with electrical microstimulation and fMRI

We describe a new method that combines microstimulation with fMRI for the detailed study of neural connectivity in the alive animal. We used specially constructed microelectrodes to stimulate directly a selected subcortical or cortical area while simultaneously measuring changes in brain activity, indexed by the blood oxygen level dependent (BOLD) signal. The exact location of the stimulation site was achieved by means of anatomical scans as well as by the study of the physiological properties of neurons. Imaging was carried out in a Biospec 4.7T/40 cm vertical bore scanner (Bruker, Inc), using pulse sequences described elsewhere (Logothetis et. al. Nature Neuroscience 1999). Electrical stimulation was delivered using a biphasic pulse generator attached to a constant-current stimulus isolation unit. Constant-current charge-balanced biphasic pulses (300usec, 50 to 150 uA, at 50 to 500 Hz) were delivered to the brain for 12.5 sec preceded and followed by 12.5 and 39 sec respectively. The compensation circuit, designed to minimize interference generated by the switching gradients during recording, was always active alleviating all gradient-induced currents in the range of the stimulation current. Local microstimulation of striate cortex yielded both local BOLD signals and activation of areas V2, V3, and MT. Microstimulation of dLGN resulted in the activation of striate cortex, as well as areas V2, V3, and MT. Our findings show that microstimulation combined with fMRI can be exquisitely used to find and study target areas of regions of electrophysiological interest