Efficient Attribute-Based Smart Contract Access Control Enhanced by Reputation Assessment

Blockchain's immutability can resist unauthorized changes of ledgers, thus it can be used as a trust enhancement mechanism to a shared system. Indeed, blockchain has been considered to solve the security and privacy issues of the Internet of Things (IoT). In this regard, most researches currently focus on the realization of various access control models and architectures, and are working towards making full use of the blockchain to secure IoT systems. It is worth noting that there has been an increasingly heavy pressure on the blockchain storage caused by dealing with massive IoT data and handling malicious access behaviors in the system, and not many countermeasures have been seen to curb the increase. However, this problem has not been paid enough attention. In this paper, we implement an attribute-based access control scheme using smart contracts in Quorum blockchain. It provides basic access control functions and conserves storage by reducing the number of smart contracts. In addition, a reputation-based technique is introduced to cope with malicious behaviors. Certain illegal transactions can be blocked by the credit-assessment algorithm, which deters possibly malicious nodes and gives more chance to well-behaved nodes. The feasibility of our proposed scheme is demonstrated by doing experiment on a testbed and conducting a case study. Finally, the system performance is assessed based on experimental measurement

Varying Levels of the Dian Lakes and the Dian Lakes Culture

Historical records state that the Dian kingdom was based on thousands of square li of rich flat land around Dianchi Lake. However, through use of a digital elevation model of the area, it is found that this area was about 800 li2—substantially less. Even if the other major Dian Lakes—Fuxian, Xinyung and Qi Lu—are included, the area increases to only about 1,000 li2. In the process of checking the area stated in the historical records, some issues warranting further exploration have been brought to light: the possibility of a human role in the recurring floods of Dianchi Lake from the 13th c CE; the idea that the settlement site found near Wangjiadun village and tentatively assigned to the early Bronze Age, could be dated to at least 4,500 BP, well before; and that the Shizhaishan and Lijiashan elite cemeteries may have looked out over water to their east. The seemingly limited area of fertile land also suggests that other sources of wealth such as trade and minerals played a greater role, and that the population was relatively small. This calls into question the nature of the socio-political structure within the Dian lakes culture

Seasonal Variations In Nutrient Concentrations and Speciation in the Chena River, Alaska

To better understand the seasonal controls on nutrient abundances, speciation, and fluxes in a watershed underlain by discontinuous permafrost, we collected water samples biweekly from the Chena River during 2005-2006 to measure inorganic and organic N, P, and Si in dissolved and particulate phases. Nitrate concentrations were low (8-14 mu M) during the winter and summer dry seasons but were elevated during the spring freshet (15-24 mu M). Ammonium varied from 8 to 13 mu M during the winter but dropped dramatically during the ice-open season to 0.1-3 mM. Phosphate was very low throughout the year (ranging from 0.03 to 0.3 mu M), reflecting the pristine condition of the watershed. Dissolved silica was high in the winter and reached its minimum during the spring freshet. DIN was the dominant species in the total N pool (60%), followed by DON (30%) and PN (10%). Most of the phosphorous was present in the particulate phase (74%), with phosphate and DOP only comprising 19% and 7%, respectively. Seasonal variations in nutrient concentrations and speciation were mostly controlled by the hydrological flow regime and biological activity in the river. Annual nutrient export fluxes from the Chena River during 2005-2006 were 51.1 x 10(6) mole-N, 1.4 x 10(6) mole-P, and 197 x 10(6) mole-Si, corresponding to an annual yield of 9.8 x 10(3) mol-N km(-2), 0.28 x 10(3) mol-P km(-2), and 37.9 x 10(3) mol-Si km(-2), respectively. Within the annual export fluxes, the spring freshet contributed about 18% of TN, 27% of TP, and 10% of Si, while the winter season contributed 11% of TN, 12% of TP, and 20% of Si. Continued climatic warming in northern watersheds will likely increase the export of nutrient species from watersheds

Towards Vision-Based Smart Hospitals: A System for Tracking and Monitoring Hand Hygiene Compliance

One in twenty-five patients admitted to a hospital will suffer from a hospital acquired infection. If we can intelligently track healthcare staff, patients, and visitors, we can better understand the sources of such infections. We envision a smart hospital capable of increasing operational efficiency and improving patient care with less spending. In this paper, we propose a non-intrusive vision-based system for tracking people's activity in hospitals. We evaluate our method for the problem of measuring hand hygiene compliance. Empirically, our method outperforms existing solutions such as proximity-based techniques and covert in-person observational studies. We present intuitive, qualitative results that analyze human movement patterns and conduct spatial analytics which convey our method's interpretability. This work is a step towards a computer-vision based smart hospital and demonstrates promising results for reducing hospital acquired infections.Comment: Machine Learning for Healthcare Conference (MLHC

High oncostatin M predicts lack of clinical remission for patients with inflammatory bowel disease on tumor necrosis factor α antagonists

The interleukin-6 family cytokine, oncostatin-M (OSM) has been associated with response to tumor necrosis factor-α antagonists (anti-TNFs) in small cohorts of patients with inflammatory bowel disease (IBD). We aimed to evaluate the association between plasma OSM concentrations and response to anti-TNFs (infliximab and adalimumab) in both ulcerative colitis (UC) and Crohn’s disease (CD). A retrospective cohort study was conducted in patients with IBD with a history of anti-TNF exposure. Blood samples, collected prior to anti-TNF exposure, were analyzed by enzyme-linked immunosorbent assay for the presence and quantity of OSM. Clinical remission was assessed at 1-year post anti-TNF exposure in addition to the occurrence of surgery, hospitalization, corticosteroid use, and adverse drug events. Lastly the threshold OSM plasma concentration associated with anti-TNF non-response was assessed by receiver operator characteristic (ROC) curve analysis. Patients with IBD (CD, n = 82; UC, n = 40) were assessed. In both UC and CD, mean pre-treatment OSM concentrations were significantly lower in those who achieved clinical remission at 1-year (p \u3c 0.0001). A threshold plasma OSM concentration of 168.7 pg/ml and 233.6 pg/ml respectively separated those who achieved clinical remission at 1-year on an anti-TNF from those who did not in CD and UC respectively (CD: area under the receiver operator characteristic curve, AUROC = 0.880, 95% CI 0.79–0.96; UC: AUROC = 0.938, 95% CI 0.87–1.00). High OSM concentrations were associated with anti-TNF discontinuation and use of rescue steroids in CD and UC. High pre-treatment OSM concentrations identify IBD patients at-risk of anti-TNF non-response at 1-year as well as other deleterious clinical outcomes

Energy Transfer From Fluorescent Proteins To Metal Nanoparticles

Energy transfer plays a significant role in numerous chemical, physical, and biological processes. While the use of fluorescent proteins in Forster resonance energy transfer (FRET) studies of biomolecules is common, energy transfer between fluorescent proteins and inorganic nanoparticles has not been explored in detail. In this study, energy transfer from fluorescent phycobiliproteins to noble metal nanoparticles was analyzed. Solutions of B-phycoerythrin (B-PE) were mixed with colloidal Au and Ag nanoparticles and were characterized by steady-state and time-resolved fluorescence spectroscopy to determine the magnitude and mechanism of the energy transfer. It was found that the protein fluorescence was quenched after the addition of metal nanoparticles. Electron microscopy and absorption spectroscopy confirmed that B-PE was adsorbed onto the nanoparticles, creating a favorable geometry for quenching. Time-resolved fluorescence spectroscopy showed that B-PE fluorescence lifetimes decreased from 2.2 ns to 0.5 and 0.6 ns upon adsorption onto Au and Ag nanoparticles, respectively, corresponding to energy transfer efficiencies of \u3e70%. Our results, which include lifetimes, efficiencies, and energy transfer distances, show that energy was transferred via the surface energy transfer (SET) mechanism, rather than FRET

Autoimmunity to hypocretin and molecular mimicry to flu in type 1 narcolepsy

Type 1 narcolepsy (T1N) is caused by hypocretin/orexin (HCRT) neuronal loss. Association with the HLA DQB1*06:02/DQA1*01:02 (98% vs. 25%) heterodimer (DQ0602), T cell receptors (TCR) and other immune loci suggest autoimmunity but autoantigens are unknown. Onset is seasonal and associated with influenza A, notably pandemic 2009 H1N1 (pH1N1) infection and vaccination (Pandemrix). Peptides derived from HCRT and influenza A, including pH1N1, were screened for DQ0602 binding and presence of cognate DQ0602 tetramer-peptide-specific CD4(+) T cells tested in 35 T1N cases and 22 DQ0602 controls. Higher reactivity to influenza pHA(273-287) (pH1N1 specific), PR8 (H1N1 pre-2009 and H2N2)-specific NP17-31 and C-amidated but not native version of HCRT54-66 and HCRT86-97 (HCRTNH2) were observed in T1N. Single-cell TCR sequencing revealed sharing of CDR3 beta TRBV4-2-CASSQETQGRNYGYTF in HCRTNH2 and pHA(273-287)-tetramers, suggesting molecular mimicry. This public CDR3 beta uses TRBV4-2, a segment modulated by T1N-associated SNP rs1008599, suggesting causality. TCR-alpha/beta CDR3 motifs of HCRT54-66-NH2 and HCRT86-97-NH2 tetramers were extensively shared: notably public CDR3 alpha, TRAV2-CAVETDSWGKLQF-TRAJ24, that uses TRAJ24, a chain modulated by T1N-associated SNPs rs1154155 and rs1483979. TCR-alpha/beta CDR3 sequences found in pHA(273-287), NP17-31, and HCRTNH2 tetramer-positive CD4(+) cells were also retrieved in single INF-gamma-secreting CD4(+) sorted cells stimulated with Pandemrix, independently confirming these results. Our results provide evidence for autoimmunity and molecular mimicry with flu antigens modulated by genetic components in the pathophysiology of T1N.Peer reviewe