A comprehensive survey on Fog Computing: State-of-the-art and research challenges

Cloud computing with its three key facets (i.e., Infrastructure-as-a-Service, Platform-as-a-Service, and Softwareas- a-Service) and its inherent advantages (e.g., elasticity and scalability) still faces several challenges. The distance between the cloud and the end devices might be an issue for latencysensitive applications such as disaster management and content delivery applications. Service level agreements (SLAs) may also impose processing at locations where the cloud provider does not have data centers. Fog computing is a novel paradigm to address such issues. It enables provisioning resources and services outside the cloud, at the edge of the network, closer to end devices, or eventually, at locations stipulated by SLAs. Fog computing is not a substitute for cloud computing but a powerful complement. It enables processing at the edge while still offering the possibility to interact with the cloud. This paper presents a comprehensive survey on fog computing. It critically reviews the state of the art in the light of a concise set of evaluation criteria. We cover both the architectures and the algorithms that make fog systems. Challenges and research directions are also introduced. In addition, the lessons learned are reviewed and the prospects are discussed in terms of the key role fog is likely to play in emerging technologies such as tactile Internet

The first comprehensive chemical profiling of Vachellia gummifera (Willd.) Kyal. & Boatwr., a plant with medicinal value

Vachellia gummifera (Willd.) Kyal. & Boatwr. is a medicinal plant endemic to Morocco that has no documented studies on its chemical composition. In this study, the chemical composition of the water/methanol (4 : 1) extracts of air-dried leaf and stem samples of Moroccan V. gummifera was determined using UHPLC-MS and NMR. In total, over 100 metabolites were identified in our study. Pinitol was the major compound in both the leaf and stem extracts, being significantly more abundant in the former. Asparagine and 3-hydroxyheteroendrin were the second most abundant compounds in the stem and leaf extracts, respectively, though both compounds were present in each tissue. The other compounds included flavonoids based on quercetin, and phenolic derivatives. Eucomic acid, only identified in the stems and was the major aromatic compound distinguishing the leaf and stem profiles. Quercetin 3-O-(6′′-O-malonyl)-β-D-glucopyranoside was identified as the major flavonoid in the leaves but was also present in the stems. Other malonylated derivatives that were all flavonol glycosides based on myricetin, kaempferol, and isorhamnetin in addition to quercetin were also identified. This is the first report of eucomic acid and malonylated compounds in Vachellia species. This report provides valuable insights into the chemotaxonomic significance of the Vachellia genus.OCP Morocco.FP05is a collaboration between Mohammed VI Polytechnic University, Rothamsted Research and Cranfield Universit

Relatively low and moderate pre-fracture serum 25-hydroxyvitamin D levels associated with the highest survival in elderly hip fracture patients in Finland: a minimum 3-year follow-up

SUMMARY: The association between serum 25-hydroxyvitamin D level and post-fracture mortality indicates beneficial relatively high serum 25-hydroxyvitamin D concentrations. A 1-year cohort study on 245 hip fracture patients in Finland indicated the lowest 3-year mortality and highest survival among patients with serum 25-hydroxyvitamin D level of 50–74 nmol/L. PURPOSE: To explore pre-fracture serum 25-hydroxyvitamin D level as a factor associated with post-fracture survival among a cohort of hip fracture patients in Finland. METHODS: A prospectively collected cohort of hip fracture patients (n = 245, 70% women) from two hospitals was followed for 3.2 post-hip fracture years. Serum 25-hydroxyvitamin D was measured in admission to the hospital and classified: < 50, 50–74, 75–99, and ≥ 100 nmol/L. Survival was analyzed with a Bayesian multivariate model. Relative survival was explored with the life table method according to serum 25-hydroxyvitamin D. Mortality according to serum 25-hydroxyvitamin D level and to the hospital was calculated. RESULTS: Mortality in the patients with serum 25-hydroxyvitamin D level of 50–74 nmol/L was significantly lower than in all other patients together at every post-fracture year. The most important factors for survival were age under 85 years; living in an actual/private home; serum 25-hydroxyvitamin D level of 50–74 nmol/L, followed by 75–99 nmol/L; ASA classes 1–2 and 3; and female sex. The mean age of patients with serum 25-hydroxyvitamin D level of 50–99 nmol/L was significantly higher than in other levels. Relative survival was highest in men, women, and patients in hospital B with serum 25-hydroxyvitamin D level of 50–74 nmol. CONCLUSION: The highest 3-year survival and the lowest mortality in this cohort appeared in patients with pre-fracture serum 25-hydroxyvitamin D level of 50–74 nmol/L. This result differs from similar studies and is lower than the recommended level of 25-hydroxyvitamin D among hip fracture patients. The results should be examined in future research with larger data. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00198-021-06094-z

Correction to: Remarkable improvement in serum 25-hydroxyvitamin levels among hip fracture patients over a 12-year period: a prospective study in South-Eastern Finland.

Hypovitaminosis D is a problem among hip fracture patients. In a 1-year cohort study comprising 245 hip fracture patients (mean age of females 81 years and males 78 years) from south-eastern Finland, the mean 25-hydroxyvitamin D [S-25(OH)D] concentration was 73(SD 31) nmol/L. Vitamin D supplementation has been integrated into our current practice. The objectives of this study are to verify vitamin D levels among hip fracture patients and to compare the results with a similar study conducted in the same two hospitals covering the same geographic area 12 years ago. A prospective cohort comprising 245 Caucasian hip fracture patients was enrolled in the study in two acute hospitals in south-eastern Finland (61A degrees N) over a 12-month period in 2015-2016. The S-25(OH)D was measured using 25-hydroxyvitamin D electrochemiluminescence binding assay. The S-25(OH)D concentrations were compared with the corresponding concentrations of a similar cohort analyzed in the same two hospitals 12 years ago. Of the 245 patients, 70% were women with a mean age of 81 (SD 10) years, while the men had a mean age of 78 (SD 12) years (p 50 nmol/L) was remarkably higher in 2015-2016 (77%) than in 2003-2004 (22%). Our results indicate that vitamin D supplementation has been widely integrated into our current practice. However, regional differences were found in the S-25(OH)D concentrations for which the reasons are unknown.Peer reviewe