A Survey on Long-Range Wide-Area Network Technology Optimizations

Long-Range Wide-Area Network (LoRaWAN) enables flexible long-range service communications with low power consumption which is suitable for many IoT applications. The densification of LoRaWAN, which is needed to meet a wide range of IoT networking requirements, poses further challenges. For instance, the deployment of gateways and IoT devices are widely deployed in urban areas, which leads to interference caused by concurrent transmissions on the same channel. In this context, it is crucial to understand aspects such as the coexistence of IoT devices and applications, resource allocation, Media Access Control (MAC) layer, network planning, and mobility support, that directly affect LoRaWAN’s performance.We present a systematic review of state-of-the-art works for LoRaWAN optimization solutions for IoT networking operations. We focus on five aspects that directly affect the performance of LoRaWAN. These specific aspects are directly associated with the challenges of densification of LoRaWAN. Based on the literature analysis, we present a taxonomy covering five aspects related to LoRaWAN optimizations for efficient IoT networks. Finally, we identify key research challenges and open issues in LoRaWAN optimizations for IoT networking operations that must be further studied in the future

Leucine supplementation improves adiponectin and total cholesterol concentrations despite the lack of changes in adiposity or glucose homeostasis in rats previously exposed to a high-fat diet

<p>Abstract</p> <p>Background</p> <p>Studies suggest that leucine supplementation (LS) has a therapeutic potential to prevent obesity and to promote glucose homeostasis. Furthermore, regular physical exercise is a widely accepted strategy for body weight maintenance and also for the prevention of obesity. The aim of this study was to determine the effect of chronic LS alone or combined with endurance training (ET) as potential approaches for reversing the insulin resistance and obesity induced by a high-fat diet (HFD) in rats.</p> <p>Methods</p> <p>Forty-seven rats were randomly divided into two groups. Animals were fed a control diet-low fat (<it>n = </it>10) or HFD (<it>n = </it>37). After 15 weeks on HFD, all rats received the control diet-low fat and were randomly divided according to treatment: reference (REF), LS, ET, and LS+ET (<it>n = </it>7-8 rats per group). After 6 weeks of treatment, the animals were sacrificed and body composition, fat cell volume, and serum concentrations of total cholesterol, HDL-cholesterol, triacylglycerol, glucose, adiponectin, leptin and tumor necrosis factor-alpha (TNF-α) were analyzed.</p> <p>Results</p> <p>At the end of the sixth week of treatment, there was no significant difference in body weight between the REF, LS, ET and LS+ET groups. However, ET increased lean body mass in rats (<it>P </it>= 0.019). In addition, ET was more effective than LS in reducing adiposity (<it>P </it>= 0.019), serum insulin (<it>P </it>= 0.022) and TNF-α (<it>P </it>= 0.044). Conversely, LS increased serum adiponectin (<it>P </it>= 0.021) levels and reduced serum total cholesterol concentration (<it>P </it>= 0.042).</p> <p>Conclusions</p> <p>The results showed that LS had no beneficial effects on insulin sensitivity or adiposity in previously obese rats. On the other hand, LS was effective in increasing adiponectin levels and in reducing total cholesterol concentration.</p

A Taxonomy of DDoS Attack Mitigation Approaches Featured by SDN Technologies in IoT Scenarios

The Internet of Things (IoT) has attracted much attention from the Information and Communication Technology (ICT) community in recent years. One of the main reasons for this is the availability of techniques provided by this paradigm, such as environmental monitoring employing user data and everyday objects. The facilities provided by the IoT infrastructure allow the development of a wide range of new business models and applications (e.g., smart homes, smart cities, or e-health). However, there are still concerns over the security measures which need to be addressed to ensure a suitable deployment. Distributed Denial of Service (DDoS) attacks are among the most severe virtual threats at present and occur prominently in this scenario, which can be mainly owed to their ease of execution. In light of this, several research studies have been conducted to find new strategies as well as improve existing techniques and solutions. The use of emerging technologies such as those based on the Software-Defined Networking (SDN) paradigm has proved to be a promising alternative as a means of mitigating DDoS attacks. However, the high granularity that characterizes the IoT scenarios and the wide range of techniques explored during the DDoS attacks make the task of finding and implementing new solutions quite challenging. This problem is exacerbated by the lack of benchmarks that can assist developers when designing new solutions for mitigating DDoS attacks for increasingly complex IoT scenarios. To fill this knowledge gap, in this study we carry out an in-depth investigation of the state-of-the-art and create a taxonomy that describes and characterizes existing solutions and highlights their main limitations. Our taxonomy provides a comprehensive view of the reasons for the deployment of the solutions, and the scenario in which they operate. The results of this study demonstrate the main benefits and drawbacks of each solution set when applied to specific scenarios by examining current trends and future perspectives, for example, the adoption of emerging technologies based on Cloud and Edge (or Fog) Computing

Tumour-derived transforming growth factor-beta signalling contributes to fibrosis in patients with cancer cachexia

Background Cachexia is a paraneoplastic syndrome related with poor prognosis. The tumour micro-environment contributes to systemic inflammation and increased oxidative stress as well as to fibrosis. The aim of the present study was to characterise the inflammatory circulating factors and tumour micro-environment profile, as potentially contributing to tumour fibrosis in cachectic cancer patients. Methods 74 patients (weight stable cancer n = 31; cachectic cancer n = 43) diagnosed with colorectal cancer were recruited, and tumour biopsies were collected during surgery. Multiplex assay was performed to study inflammatory cytokines and growth factors. Immunohistochemistry analysis was carried out to study extracellular matrix components. Results Higher protein expression of inflammatory cytokines and growth factors such as epidermal growth factor, granulocyte-macrophage colony-stimulating factor, interferon-alpha, and interleukin (IL)-8 was observed in the tumour and serum of cachectic cancer patients in comparison with weight-stable counterparts. Also, IL-8 was positively correlated with weight loss in cachectic patients (P = 0.04; r = 0.627). Immunohistochemistry staining showed intense collagen deposition (P = 0.0006) and increased presence of alpha-smooth muscle actin (P < 0.0001) in tumours of cachectic cancer patients, characterizing fibrosis. In addition, higher transforming growth factor (TGF)-beta 1, TGF-beta 2, and TGF-beta 3 expression (P = 0.003, P = 0.05, and P = 0.047, respectively) was found in the tumour of cachectic patients, parallel to p38 mitogen-activated protein kinase alteration. Hypoxia-inducible factor-1 alpha mRNA content was significantly increased in the tumour of cachectic patients, when compared with weight-stable group (P = 0.005). Conclusions Our results demonstrate TGF-beta pathway activation in the tumour in cachexia, through the (non-canonical) mitogen-activated protein kinase pathway. The results show that during cachexia, intratumoural inflammatory response contributes to the onset of fibrosis. Tumour remodelling, probably by TGF-beta-induced transdifferentiation of fibroblasts to myofibroblasts, induces unbalanced inflammatory cytokine profile, angiogenesis, and elevation of extracellular matrix components (EMC). We speculate that these changes may affect tumour aggressiveness and present consequences in peripheral organs10510451059CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorCNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulosem informaçãosem informação2012/50079-0; 2016/08726-1; 2016/04000-