LEE: Light‐Weight Energy‐Efficient encryption algorithm for sensor networks

Data confidentiality in wireless sensor networks is mainly achieved by RC5 and Skipjack encryption algorithms. However, both algorithms have their weaknesses, for example RC5 supports variable-bit rotations, which are computationally expensive operations and Skipjack uses a key length of 80-bits, which is subject to brute force attack. In this paper we introduce a light-weight energy- fficient encryption-algorithm (LEE) for tiny embedded devices, such as sensor network nodes. We present experimental results of LEE under real sensor nodes operating in TinyOS. We also discuss the secrecy of our algorithm by presenting a security analysis of various tests and cryptanalytic attacks

Molecular identification of CTX-M, TEM and SHV β-lactamases in �Klebsiella pneumoniae isolated from respiratory system of patients in the ICU of educational hospitals in Tehran

Background: Extended-spectrum beta-lactamases (ESBL) producing isolates of Klebsiella pneumoniae which have been increased in the hospitals were resulting in limitation of therapeutic options. The aims of this study were to evaluate the antibiotic susceptibility pattern and presence of ESBL genes in clinical isolates of Klebsiella pneumoniae from patients admitted to the intensive care units (ICUs). Materials and Methods: In this descriptive cross-sectional study, a total of 65 Klebsiella pneumoniae strains were isolated from ICUs of educational hospitals in Tehran. Identification was performed using biochemical tests and the antimicrobial susceptibility was performed as recommended by the Clinical and Laboratory Standards Institute (CLSI). Molecular analysis of the ESBL genes was performed by Multiplex PCR (M-PCR). Results: Most of the isolates were resistant to Cotrimoxazole (72.3), Gentamicin (67.7) and Ampicillin (69.2) and the highest susceptibility was seen for Ciprofloxacin (50.8) Tetracycline (49.2), Imipenem (46.3) and Ceftriaxone (43.1). Among the ESBL-producing genes, blaCTX-M (55.3 ) was the most prevalent, followed by blaTEM (41.5 ) and blaSHV (10.7 ). The results showed that 1.5 of the isolates had concurrently blaTEM/ blaSHV and blaSHV/ blaCTX-M genes and 21.6 of isolates the blaTEM/ blaCTX-M genes. Conclusion: These findings reveal the high prevalence of multi drug resistant and ESBL-producing Klebsiella pneumoniae in patients hospitalized in ICUs and emphasize the need for appropriate infection control policies

Numerical study of size-dependent instability of nems considering molecular force and elastic support conditions

Nano-electromechanical systems (NEMS) sensors are recently used as powerful medical detectors for detection of disease. In this research paper, the modified couple stress non-classic continuum theory is applied to examine the size effect on the pull-in instability of beam-type NEMS sensor at submicron separations considering the van der Waals attraction. The proposed model takes the non-classic support conditions into account using rotational springs at supported end of the simply supported nano-beam. In order to solve the nonlinear constitutive equation of the nano-beams, finite difference numerical solution employed. The results reveal significant influence of the size dependency, elastic support conditions and van der Waals attraction on the pull-in characteristics of beam-type NEMS. © 2006-2014 Asian Research Publishing Network (ARPN)

The Influence of Geometrical Shape Changes on Wave Overtopping: a Laboratory and SPH Numerical Study

This paper presents laboratory investigations of four “retrofit” suggestions for attenuating the overtopping from vertical seawall. Two-dimensional physical model experiments were performed on a vertical seawall with a 1:20 sloping foreshore. Additionally, a Lagrangian, particle based SPH methodology was employed to simulate the wave hydrodynamics and overtopping for the recurve configuration. The experimental and numerical results confirm satisfactory performance. For the tested configurations in the laboratory, the mean overtopping discharges decreased over 60% and maximum individual discharge decreased 40% on recurve wall under both impulsive and non-impulsive conditions. A significant reduction was also observed in mitigating overtopping discharge by using model vegetation and reef breakwater, while diffraction pillar was not found satisfactory

Evaluation of response to preoperative chemotherapy versus surgery alone in gastroesophageal cancer: Tumor resectability, pathologic results and post-operative complications

Gastroesophageal cancer is one of the most common types of cancer worldwide. Despite significant developments in management, 5-year survival in the developing world is less than 20 percent. Due to restricted research about the impact of preoperative chemotherapy (POC) on tumor resection, pathological response and postoperative complications in Iran, we designed and implemented the present retrospective cross- sectional study on 156 patients with gastroesophageal cancer (GEc) between 2013 and 2015 at Shariati Hospital of Tehran. Two groups were included, the first group had previously received preoperative chemotherapy and the second group had only undergone surgery. All patients were followed for at least one year after the operation in terms of tumor recurrence, relapse free survival and one-year survival. The two groups were eventually compared regarding tumor resection, pathological response, postoperative complications, recurrence rate and survival. The mean age was 66.5± 7.3 years and 78 percent were male. The tumor resectability, pathological response and postoperative complications in the group which received POC were 93.5, 21.8 and 12.8, respectively, and in the surgery alone group figures for tumor resection and postoperative complications were 76 and 29.5, respectively. Also based on our study the 5-year survival in the POC group was better (79.5 vs. 66.5). Using standard neoadjuvant regimens (preoperative chemotherapy/ chemoradiotherapy) beforesurgery could increase tumor resectability, pathological response, and improve the general status of the patients. Therefore using POC may be recommended over surgery alone. © 2016, Asian Pacific Journal of Cancer Prevention

Phenotypic and genotypic characteristics of tetracycline resistant Acinetobacter baumannii isolates from nosocomial infections at Tehran hospitals

Objective(s): To date, the most important genes responsible for tetracycline resistance among Acinetobacter baumannii isolates have been identified as tet A and tet B. This study was carried out to determine the rate of resistance to tetracycline and related antibiotics, and mechanisms of resistance. Materials and Methods: During the years 2010 and 2011, a total of 100 A. baumannii isolates were recovered from patients in different hospitals of Tehran, Iran. Antimicrobial susceptibility to tetracycline, minocycline, doxicycline and tigecycline was evaluated by E-test. Polymerase chain reaction (PCR) of the tet A and tet B genes was performed using specific primers, after which the isolates were subjected to Repetitive Extragenic Palindromic-PCR (PCR) to identify the major genotypes. Results: Of all isolates, 89 were resistant to tetracycline (MIC50 = 32 mu g/ml, MIC90 = 512 mu g/ml). Minocycline with the resistant rate of 35 (MIC50 = 16 mu g/ml, MIC90 = 32 mu g/ml) and doxicycline with the resistant rate of 25 (MIC50 = 16 mu g/ml, MIC90= 32 mu g/ml) have a good activity against A. baumannii isolates. All isolates were sensitive to tigecycline. Frequencies of tet B and tet A genes and coexistence of tet A and tet B among the isolates resistant to tetracycline, were 87.6, 2.2 and 1.1, respectively. Distribution of REP-types among A. baumannii isolates was types A (40), B (30), C (10), D (5) and E (5). Conclusion: It seems that tet A and tet B genes play an important role in the induction of resistance towards tetracyclines used in this study. It is suggested that further studies focus on other antimicrobial drugs and combinations in order to achieve a successful therapy against multi drug resistance (MDR) A. baumannii strains in Iran