Shahid A. Khan

Future Internet: The Internet of Things Architecture, Possible Applications and Key Challenges

The Internet is continuously changing and evolving. The main communication form of present Internet is human-human. The Internet of Things (IoT) can be considered as the future evaluation of the Internet that realizes machine-to-machine (M2M) learning. Thus, IoT provides connectivity for everyone and everything. The IoT embeds some intelligence in Internet-connected objects to communicate, exchange information, take decisions, invoke actions and provide amazing services. This paper addresses the existing development trends, the generic architecture of IoT, its distinguishing features and possible future applications. This paper also forecast the key challenges associated with the development of IoT. The IoT is getting increasing popularity for academia, industry as well as government that has the potential to bring significant personal, professional and economic benefits.

Characterization of Salmonella enterica Derivatives Harboring Defined aroC and Salmonella Pathogenicity Island 2 Type III Secretion System (ssaV) Mutations by Immunization of Healthy Volunteers

ABSTRACT The attenuation and immunogenicity of two novel Salmonella vaccine strains, Salmonella enterica serovar Typhi (Ty2 ΔaroC ΔssaV, designated ZH9) and S. enterica serovar Typhimurium (TML ΔaroC ΔssaV, designated WT05), were evaluated after their oral administration to volunteers as single escalating doses of 107, 108, or 109 CFU. ZH9 was well tolerated, not detected in blood, nor persistently excreted in stool. Six of nine volunteers elicited anti-serovar Typhi lipopolysaccharide (LPS) immunoglobulin A (IgA) antibody-secreting cell (ASC) responses, with three of three vaccinees receiving 108 and two of three receiving 109 CFU which elicited high-titer LPS-specific serum IgG. WT05 was also well tolerated with no diarrhea, although the administration of 108 and 109 CFU resulted in shedding in stools for up to 23 days. Only volunteers immunized with 109 CFU of WT05 mounted detectable serovar Typhimurium LPS-specific ASC responses and serum antibody responses were variable. These data indicate that mutations in type III secretion systems may provide a route to the development of live vaccines in humans and highlight significant differences in the potential use of serovars Typhimurium and Typhi.

Salmonella typhi and S typhimurium derivatives harbouring deletions in aromatic biosynthesis and Salmonella Pathogenicity Island-2 (SPI-2) genes as vaccines and vectors.

The S. typhimurium strain (TML deltaaroC deltassaV) WT05, harbouring defined deletions in genes involved in both the aromatic biosynthesis pathway (aroC) and the Salmonella Pathogenicity Island-2 (SPI-2) (ssaV) was shown to be significantly attenuated in C57 BL/6 interferon gamma knockout mice following oral inoculation. Similarly, the S. typhi strain (Ty2 deltaaroC deltassaV) ZH9 harbouring the aroC and ssaV mutations propagated less efficiently than wild type in human macrophages. These studies demonstrated the attractive safety profile of the aroC ssaV mutant combination. Strains S. typhimurium (TML deltaaroC deltassaV ) WT05 and S. typhi (Ty2 deltaaroC deltassaV) ZH9 were subsequently tested as vaccine vectors to deliver E. coli heat-labile toxin (LT-B) mucosally to mice. Mice inoculated orally with S. typhimurium (TML deltaaroC deltassaV) WT05 expressing LT-B (WT05/LT-B) elicited high titres of both LT-specific serum IgG and intestinal IgA, although no specific IgA was detected in the vagina. Similarly, intranasal inoculation of mice with S. typhi (Ty2 deltaaroC deltassaV) ZH9 expressing LT-B (ZH9/LT-B) elicited even higher titres of LT-specific serum antibody as well as LT-specific Ig in the vagina. We conclude that deltaaroC deltassaV strains of Salmonella are highly attenuated and are promising candidates both as human typhoid vaccines and as vaccine vectors for the delivery of heterologous antigens.

Optimization of Salmonella enterica Serovar Typhi ΔaroC ΔssaV Derivatives as Vehicles for Delivering Heterologous Antigens by Chromosomal Integration and In Vivo Inducible Promoters

ABSTRACT Novel candidate live oral vaccines based on a Salmonella enterica serovar Typhi ZH9 (Ty2 ΔaroC ΔssaV) derivative that directed the expression of either the B subunit of Escherichia coli heat-labile toxin or hepatitis B virus core antigen from the bacterial chromosome using the in vivo inducible ssaG promoter were constructed. The levels of attenuation of the two S. enterica serovar Typhi ZH9 derivatives were similar to that of the parent as assessed by measuring the replication of bacteria within human macrophage-like U937 cells. The expression of heterologous antigen in the respective S. enterica serovar Typhi ZH9 derivatives was up-regulated significantly within U937 cells compared to similar S. enterica serovar Typhi ZH9 derivative bacteria grown in modified Luria-Bertani broth supplemented with aromatic amino acids. Immunization of mice with these S. enterica serovar Typhi ZH9 derivatives stimulated potent antigen-specific serum immunoglobulin G responses to the heterologous antigens.

Comparing robotic, laparoscopic and open cystectomy: a systematic review and meta-analysis

OBJECTIVE To conduct a systematic review and meta-analysis comparing outcomes between Open Radical Cystectomy (ORC), Laparoscopic Radical Cystectomy (LRC) and Robot-assisted Radical Cystectomy (RARC). RARC is to be compared to LRC and ORC and LRC compared to ORC. MATERIAL AND METHODS A systematic review of the literature was conducted, collating studies comparing RARC, LRC and ORC. Surgical and oncological outcome data were extracted and a meta-analysis was performed. RESULTS Twenty-four studies were selected with total of 2,104 cases analyzed. RARC had a longer operative time (OPT) compared to LRC with no statistical difference between length of stay (LOS) and estimated blood loss (EBL). RARC had a significantly shorter LOS, reduced EBL, lower complication rate and longer OPT compared to ORC. There were no significant differences regarding lymph node yield (LNY) and positive surgical margins (PSM.) LRC had a reduced EBL, shorter LOS and increased OPT compared to ORC. There was no significant difference regarding LNY. CONCLUSION RARC is comparable to LRC with better surgical results than ORC. LRC has better surgical outcomes than ORC. With the unique technological features of the robotic surgical system and increasing trend of intra-corporeal reconstruction it is likely that RARC will become the surgical option of choice.

Salmonella enterica serovar Typhimurium interaction with dendritic cells: impact of the sifA gene

Salmonella enterica serovar Typhimurium (S. Typhimurium) and several mutant derivatives were able to enter efficiently murine bone marrow‐derived dendritic cells using mechanisms predominantly independent of the Salmonella pathogenicity island 1 type III secretion system. The levels of intracellular bacteria did not increase significantly over many hours after invasion. Using fluid endocytic tracers and other markers, S. Typhimurium‐containing vacuoles (SCVs) were physically distinguishable from early endocytic compartments. Fifty to eighty per cent of SCVs harbouring wild‐type S. Typhimurium or aroA, invH and ssaV mutant derivatives were associated with late endosome markers. In contrast, S. Typhimurium sifA was shown to escape the SCVs into the cytosol of infected dendritic cells. S. Typhimurium aroC sifA was more efficient than S. Typhimurium aroC in delivering a eukaryotic promoter‐driven green fluorescent protein reporter gene for expression in dendritic cells. In contrast, S. Typhimurium aroC sifA did not detectably increase the efficiency of MHC class I presentation of the model antigen ovalbumin to T cells compared to a similar aroC derivative. Mice infected with the S. Typhimurium aroC sifA expressing ovalbumin did not develop detectably enhanced levels of cytotoxic T cell or interferon‐γ production compared to S. Typhimurium aroC derivatives.

Mutation of waaN Reduces Salmonella enterica Serovar Typhimurium-Induced Enteritis and Net Secretion of Type III Secretion System 1-Dependent Proteins

ABSTRACT Mutation of waaN, a gene involved in lipid A biosynthesis, reduced enteropathogenic responses induced bySalmonella enterica serovar Typhimurium in bovine ligated ileal loops. However, the secretion of key virulence determinants was also reduced, and therefore the reduction in enteropathogenicity cannot be solely attributed to a reduction in biological activity of lipid A.

Mutual Coupling Reduction for High-Performance Densely Packed Patch Antenna Arrays on Finite Substrate

This paper reports on an effective mutual coupling suppression technique in which a metamaterial superstrate is placed in between the elements of densely packed microstrip phased array. Modified complementary split ring resonators are printed on the decoupling superstrate slab which caters for both surface and space wave effects. A detailed analysis of this proposed scheme is carried out on a low as well as on a high-permittivity substrate. Coupling suppression of 27 and 11 dB is achieved experimentally on the low- and high-permittivity substrates, respectively, with an element separation of λo/8. The design is compact and easy to realize and it removes drawback of poor front-to-back ratio previously reported in other decoupling techniques. In addition to high-coupling suppression, the decoupling slab can be added or removed in real time which makes this technique versatile for various applications having stringent performance requirements.

Vertical Handover Necessity Estimation Based on a New Dwell Time Prediction Model for Minimizing Unnecessary Handovers to a WLAN Cell

In this work, we devise a vertical handover necessity estimation (HNE) method to minimize unnecessary handovers for a mobile node (MN) entering a WLAN cell. The method relies on a new model for prediction of dwell time and computation of certain threshold values. By comparing the predicted dwell time with those thresholds, a MN is able to make decision whether it should perform handover to a WLAN cell, while keeping the probability of handover failure and probability of unnecessary handover within bounds. Simulation results obtained from Monte-Carlo experiments prove validity of the proposed model. We also compare this model with existing models for minimizing unnecessary handovers. We further enhance the analytical model by incorporating the throughput gain in HNE and show that this can further optimize handover decision in heterogenous networks.

A dynamic non-circular iris localization technique for non-ideal data

Display Omitted Robust iris inner contour localization within a sliding window.A fast and reliable technique for the iris outer contour localization.Iris contours regularization.Tolerance to rotated-iris images, specular reflections, hair, eyelids, and glasses.Applicable in real-time applications. Iris localization plays a decisive role in the overall iris biometric systems performance, because it isolates the valid part of iris. This study proposes a reliable iris localization technique. It includes the following. First, it extracts the iris inner contour within a sliding-window in an eye image using a multi-valued adaptive threshold and the two-dimensional (2D) properties of binary objects. Then, it localizes the iris outer contour using an edge-detecting operator in a sub image centered at the pupil center. Finally, it regularizes the iris contours to compensate for their non-circular structure. The proposed technique is tested on the following public iris databases: CASA V1.0, CASIA-Iris-Lamp, IITD V1.0, and the MMU V1.0. The experimental and accuracy results of the proposed scheme compared with other state-of-the-art techniques endorse its satisfactory performance.