Impact of mobility on the IoT MAC infrastructure: IEEE 802.15.4e TSCH and LLDN platform

Realizing the target of high reliability and availability is a crucial concept in the IoT context. Different types of IoT applications introduce several requirements and obstacles. One of the important aspects degrading network performance is the node mobility inside the network. Without a solid and adaptive mechanism, node mobility can disrupt the network performance due to dissociations from the network. Hence, reliable techniques must be incorporated to tackle the overhead of node movement. In this paper, the overhead of mobility on both IEEE 802.15.4e timeslotted channel hopping (TSCH) and low latency deterministic (LLDN) modes is investigated. These two modes can be considered as the MAC layer of the IoT paradigm because of their importance and resilience to different network obstacles. In addition, the set of metrics and limitations that influence the network survivability will be identified to ensure efficient mobile node handling process. Both TSCH and LLDN have been implemented via the Contiki OS to determine their functionality. TSCH has been demonstrated to have better node connectivity due to the impact of frame collision in LLDN. In addition, by neglecting the overhead of collision, the LLDN has been shown to have better connectivity and low radio duty cycle (RDC)

Tackling Mobility in Low Latency Deterministic Multihop IEEE 802.15.4e Sensor Network

Providing reliable services for low latency (LL) applications within the IoT context is a challenging issue. Several wireless sensor network (WSN) applications require deterministic systems that ensure a reliable and low latency aggregation service. The IEEE 802.15.4e standard, which is considered as the backbone of the IoT regarding WSN, has presented the low-latency deterministic network mode (LLDN) that can fulfil the major requirements of low latency applications. Meanwhile, several LL applications, for example in the automotive industry, demand the support of sensor node mobility which in turn affects network performance. Node mobility triggers several dissociations from the network that will increase latency and degrade node throughput. In this paper, we investigate the impact of node mobility over the LLDN mode while defining key factors that maximize latency and degrade throughput. In addition, an enhanced version of the LLDN mode is presented and evaluated that supports node mobility while maintaining the targeted limits of LL application requirements. The proposed mobility aware (MA-LLDN) technique manages to reduce the dissociation overhead by a factor of 75% while the packet delivery ratio (PDR) has been enhanced by 30%. Furthermore, this paper presents an analytical model that provides a snapshot of the tradeoff process between different metrics in the IEEE 802.15.4e LLDN design, which must be considered prior network deployment in mobile LL applications

Dynamic cluster head election protocol for mobile wireless sensor networks

A dynamic cluster head election protocol (DCHEP) is proposed in this work to improve network availability and energy efficiency for mobile wireless sensor networks (WSNs) under the beacon-enabled IEEE 802.15.4 standard. The proposed protocol (DCHEP) is developed and simulated using CASTALIA/OMNET++ with a realistic radio model and node behaviour. DCHEP improves the network availability and lifetime and maintains clusters hierarchy in a proactive manner even in a mobile WSN where all the nodes including cluster heads (CHs) are mobile, this is done by dynamically switching CHs allowing nodes to act as multiple backup cluster heads (BCHs) with different priorities based on their residual energy and connectivity to other clusters. DCHEP is a flexible and scalable solution targeted for dense WSNs with random mobility. The proposed protocol achieves an average of 33% and 26% improvement to the availability and energy efficiency respectively compared with the original standard

Spontaneous Intracranial Hypotension with Magnetic Resonance Localisation of Spinal Cerebrospinal Fluid Leak

To increase the awareness of spontaneous intracranial hypotension (SIH), we report in this paper a middle-aged woman who presented with an intractable headache that worsened in sitting and standing positions (a postural headache). Magnetic resonance imaging (MRI) of the spine demonstrated a cerebrospinal fluid (CSF) leak at the level of the cervical spine, in addition to typical features in a brain MRI, including symmetrical subdural collections, circumferential dural enhancement and features of midbrain sagging. The patient underwent a surgical repair of the cervical CSF leak which resulted in a dramatic symptomatic improvement that was confirmed by follow-up imaging

Clinical and Laboratory Manifestations of Yemeni Patients with Systemic Lupus Erythematosus

Objectives: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterised by multi-systemic involvement. This is the first study undertaken to determine the relationships between serological marker positivity and age, gender, signs and symptoms, risk factors and the treatment of SLE in Yemen. Methods: We investigated the cases of 149 patients with SLE admitted to Al-Thawra Hospital in Sana’a city between November 2009 and November 2010. Of the 149 patients, females represented 75.2% and males, 24.8%. Results: The most frequent presenting signs and symptoms were fatigue (84.6%), fever (81.9%), arthropathy (81.2%), anaemia (64.4%), photosensitivity (54.4%), renal involvement (53%), malar rash (52.3%), and alopecia (49%). Antinuclear antibodies (ANA) were detected in 95.3% of the patients and were associated significantly with most clinical presentations, except weight loss, hypertension and serositis. Anti-ds deoxyribonucleic acid (anti-dsDNA) was detected in 59.7% of the patients, and was associated significantly with fever and fatigue. Anti-Smith (anti-Sm) antibodies were detected in 27.5% of the patients, but were not significantly associated with all clinical presentations. Social stress was the most important risk factor for inducing SLE, with an odds ratio (OR) of 6.0, followed by common exposure to sunlight (OR = 2.2). Conclusion: In this study, SLE was more prevalent among females and young adults. The clinical presentation was characterised by a high incidence of fatigue and fever, and a low incidence of oral ulcers and serositis. ANA was associated with most clinical presentations except weight loss, hypertension, and serositis. AntidsDNA antibodies were most frequently associated with fever, fatigue and hypertension. There was no significant association of the anti-Sm antibodies with any clinical presentations

The effect of wastewater disposal on the water quality and phytoplankton in Erbil wastewater channel.

In this study, phytoplankton density, chlorophyll-a, and selected physico- chemical parameters were investigated in Erbil wastewater channel. The surveys were carried out monthly from May 2003 to April 2004. Samplings were established on three sites from headwaters to the mouth. The results showed that pH was in alkaline side of neutrality, with significant differences (

Preparation and study the mechanical properties of CMC/PVA composites by sound waves

The CMC/PVA composite membranes were prepared by casting method, the appropriate weight of CMC was variable (0.1, 0.15, 0.2, 0.25 and 0.3 gm) was dissolved in (25ml) of distilled water under stirring and heat (80?C) for (30 min.) then add the PVA with different weights (0.2, 0.4 and 0.6 gm) for each CMC weight. In order to evaluate the mechanical properties of CMC/PVA composite the ultrasonic measurements were performed at the samples , these properties are ultrasonic velocity, compressibility, acoustic impedance and bulk modulus, were made at fixed frequency (f =2.5 KHz), another acoustic mechanical properties were measured and calculated at a same time such as the ultrasonic wave amplitude before and after absorption by composite were measured using oscilloscope ,then we calculated absorption coefficient , transmittance and the reflected pressure ratio of the sound. It was found that there is significant relationship between ultrasonic velocity and material properties also results show that adding PVA affects on the density then the absorption of the ultrasonic waves inside the composites samples. Keywords: Carboxy methylcellulose; polyvinyle alcohol; mechanical properties; casting method

In-vitro Cytotoxicity and In-silico Insights of the Multi-target Anticancer Candidates from Haplophyllum tuberculatum

This study aimed to investigate the anticancer activity of Haplophyllum tuberculatum(Forsk.) aerial parts ethanol extract and fractions and reveal the potential anticancer targets, binding modes, pharmacokinetics, and toxicity properties of its phytoconstituents. MTT assay was used to investigate the anticancer activity. TargetNet, ChemProt version 2.0, and CLC-Pred web servers were used for virtual screening, and Cresset Flare software was used for molecular docking with the 26 predicted targets. Moreover, pkCSM, swiss ADME, and eMolTox web servers were used to predict pharmacokinetics and safety. Ethanolic extracts of H. tuberculatum on HepG2 and HeLa cell lines showed promising activities with IC50 values 54.12 and 48.1 µg/mL, respectively. Further, ethyl acetate fraction showed the highest cytotoxicity on HepG2 and HeLa cell lines with IC50 values 41.7 and 52.31 µg/mL. Of 70 compounds screened virtually, polygamain, justicidin A, justicidin B, haplotubine, kusunokinin, and flindersine were predicted as safe anticancer drugs candidates. They showed the highest binding scores with targets involved in cell growth, proliferation, survival, migration, tumor suppression, induction of apoptosis, metastasis, and drug resistance. Our findings revealed the potency of H. tuberculatum as a source of anticancer candidates that further studies should support

Acacia senegal gum exudate offers protection against cyclophosphamide-induced urinary bladder cytotoxicity

Cylophosphamide (CYCL) is a strong anticancer and immunosuppressive agent but its urotoxicity presents one of the major toxic effects that limit its wide usage particularly in high dose regimens. Therefore, this study aimed to investigate Acacia Senegal gum exudate, Gum Arabic (GA), for its possible role as a natural, nontoxic agent against CYCL-induced urotoxicity. Male Swiss albino rats were exposed to CYCL (150 mg/kg BW, once i.p) with or without GA oral supplementation (7.5 g/kg/day for 6 days) through drinking water. Glutathione (GSH), Malondialdehyde (MDA) and Nitric oxide (NO) bladder contents were assessed. Responsiveness of the bladder rings to acetylcholine (ACh) in vitro, microscopic and macroscopic features are also investigated. CYCL produced pronounced harmful effects on bladder urothelial lining with significant increases in (MDA) and NO levels in the tissue homogenates. Bladder-GSH content is dropped by over 60% following CYCL injection. Bladder contractility, as measured by its responsiveness to ACh, recorded a marked reduction. The isolated bladders exhibited such macroscopic changes as severe edema, inflammation and extravasation. The bladder weight increased as well. Histological changes were evident in the form of severe congestion, petechial hemorrhage and chronic inflammatory reaction in the lamina propria accompanied with desquamated epithelia. GA, a potential protective agent, produced an almost complete reversal of NO induction, lipid peroxidation or cellular GSH bladder contents in the GA + CYCL-treated group. Likewise, bladder inflammation and edema were reduced. Bladder rings showed a remarkable recovery in their responsiveness to ACh. Bladder histological examination showed a near normal configuration and structural integrity, with a significant reduction in inflammation and disappearance of focal erosions. These remarkable effects of GA may be attributed to its ability to neutralize acrolein, the reactive metabolite of CYCL and/or the resultant reactive oxygen metabolites, through a scavenging action. GA may limit the cascading events of CYCL-induced damage, initiating a cytoprotective effect leading to structural and functional recovery of the bladder tissues