Addressless: A New Internet Server Model to Prevent Network Scanning

Eliminating unnecessary exposure is a principle of server security. The huge IPv6 address space enhances security by making scanning infeasible, however, with recent advances of IPv6 scanning technologies, network scanning is again threatening server security. In this paper, we propose a new model named addressless server, which separates the server into an entrance module and a main service module, and assigns an IPv6 prefix instead of an IPv6 address to the main service module. The entrance module generates a legitimate IPv6 address under this prefix by encrypting the client address, so that the client can access the main server on a destination address that is different in each connection. In this way, the model provides isolation to the main server, prevents network scanning, and minimizes exposure. Moreover it provides a novel framework that supports flexible load balancing, high-availability, and other desirable features. The model is simple and does not require any modification to the client or the network. We implement a prototype and experiments show that our model can prevent the main server from being scanned at a slight performance cost

Early-Life Exposure to Polycyclic Aromatic Hydrocarbons and ADHD Behavior Problems

Importance Polycyclic aromatic hydrocarbons are widespread urban air pollutants from combustion of fossil fuel and other organic material shown previously to be neurotoxic. Objective In a prospective cohort study, we evaluated the relationship between Attention Deficit Hyperactivity Disorder behavior problems and prenatal polycyclic aromatic hydrocarbon exposure, adjusting for postnatal exposure. Materials and Methods Children of nonsmoking African-American and Dominican women in New York City were followed from in utero to 9 years. Prenatal polycyclic aromatic hydrocarbon exposure was estimated by levels of polycyclic aromatic hydrocarbon- DNA adducts in maternal and cord blood collected at delivery. Postnatal exposure was estimated by the concentration of urinary polycyclic aromatic hydrocarbon metabolites at ages 3 or 5. Attention Deficit Hyperactivity Disorder behavior problems were assessed using the Child Behavior Checklist and the Conners Parent Rating Scale- Revised. Results High prenatal adduct exposure, measured by elevated maternal adducts was significantly associated with all Conners Parent Rating Scale-Revised subscales when the raw scores were analyzed continuously (N = 233). After dichotomizing at the threshold for moderately to markedly atypical symptoms, high maternal adducts were significantly associated with the Conners Parent Rating Scale-Revised DSM-IV Inattentive (OR = 5.06, 95% CI [1.43, 17.93]) and DSM-IV Total (OR = 3.37, 95% CI [1.10, 10.34]) subscales. High maternal adducts were positivity associated with the DSM-oriented Attention Deficit/Hyperactivity Problems scale on the Child Behavior Checklist, albeit not significant. In the smaller sample with cord adducts, the associations between outcomes and high cord adduct exposure were not statistically significant (N = 162). Conclusion The results suggest that exposure to polycyclic aromatic hydrocarbons encountered in New York City air may play a role in childhood Attention Deficit Hyperactivity Disorder behavior problems

Multidirectional effects of Sr-, Mg-, and Si-containing bioceramic coatings with high bonding strength on inflammation, osteoclastogenesis, and osteogenesis

Ideal coating materials for implants should be able to induce excellent osseointegration, which requires several important parameters, such as good bonding strength, limited inflammatory reaction, balanced osteoclastogenesis and osteogenesis, to gain well-functioning coated implants with long-term life span after implantation. Bioactive elements, like Sr, Mg and Si, have been found to play important roles in regulating the biological responses. It is of great interest to combine bioactive elements for developing bioactive coatings on Ti-6Al-4V orthopedic implants to elicit multidirectional effects on the osseointegration. In this study, Sr, Mg and Si-containing bioactive Sr2MgSi2O7 (SMS) ceramic coatings on Ti-6Al-4V were successfully prepared by plasma-spray coating method. The prepared SMS coatings have significantly higher bonding strength (~37MPa) than conventional pure hydroxyapatite (HA) coatings (mostly in the range of 15-25 MPa). It was also found that the prepared SMS coatings switch the macrophage phenotype into M2 extreme, inhibiting the inflammatory reaction via the inhibition of Wnt5A/Ca2+ and Toll-like receptor (TLR) pathways of macrophages. In addition, the osteoclastic activities were also inhibited by SMS coatings. The expression of osteoclastogenesis related genes (RANKL and MCSF) in bone marrow derived mesenchymal cells (BMSCs) with the involvement of macrophages was decreased, while OPG expression was enhanced on SMS coatings compared to HA coatings, indicating that SMS coatings also downregulated the osteoclastogenesis. However, the osteogenic differentiation of BMSCs with the involvement of macrophages was comparable between SMS and HA coatings. Therefore, the prepared SMS coatings showed multidirectional effects, such as improving bonding strength, reducing inflammatory reaction and downregulating osteoclastic activities, but maintaining a comparable osteogenesis, as compared with HA coatings. The combination of bioactive elements of Sr, Mg and Si into bioceramic coatings can be a promising method to develop bioactive implants with multifunctional properties for orthopaedic application

Nutrient element-based bioceramic coatings on titanium alloy stimulating osteogenesis by inducing beneficial osteoimmmunomodulation

A paradigm shift has taken place in which bone implant materials has gone from being relatively inert to having immunomodulatory properties, indicating the importance of immune response when these materials interact with the host tissues. It has therefore become important to endow the implant materials with immunomodulatory properties favouring osteogenesis and osseointegration. Strontium, zinc and silicon are bioactive elements that have important roles in bone metabolism and that also elicit significant immune responses. In this study, Sr-, Zn- and Si-containing bioactive Sr2ZnSi2O7 (SZS) ceramic coatings on Ti–6Al–4V were successfully prepared by a plasma-spray coating method. The SZS coatings exhibited slow release of the bioactive ions with significantly higher bonding strength than hydroxyapatite (HA) coatings. SZS-coated Ti–6Al–4V elicited significant effects on the immune cells, inhibiting the release of pro-inflammatory cytokines and fibrosis-enhancing factors, while upregulating the expression of osteogenic factors of macrophages; moreover, it could also inhibit the osteoclastic activities. The RANKL/RANK pathway, which enhances osteoclastogenesis, was inhibited by the SZS coatings, whereas the osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs) was significantly enhanced by the SZS coatings/macrophages conditioned medium, probably via the activation of BMP2 pathway. SZS coatings are, therefore, a promising material for orthopaedic applications, and the strategy of manipulating the immune response by a combination of bioactive elements with controlled release has the potential to endow biomaterials with beneficial immunomodulatory properties

Observed and simulated changes in extreme precipitation and cold surges in China: 1961–2005

In the present work, precipitation and temperature related climate extremes are examined, with a focus on Mainland China. The objectives of this study are a) to identify targeted climate extremes and their changes during the last decades, and b) to examine the ability of current global climate models to reproduce identified patterns of change. The observed change in extreme precipitation from 1961 to 2000 is investigated using a set of indices, and the change simulated by global climate models is evaluated. In order to find an appropriate gridding method for the extreme indices in model evaluations, the effects of two different methods for estimating indices from station data are examined: one set interpolated from indices at stations (EISTA) and the other calculated from gridded precipitation (EIGRID). Results show that there is a large difference between the two, especially at coarser resolution, and suggests that EIGRID indices are more appropriate to evaluate model simulated precipitation extremes. During the period in question, observed extreme precipitation amounts increased in most parts of China, the only exception being northern China, where there was a decreasing trend. The trend of consecutive dry days (CDD) observed there is generally opposite to that of extreme precipitation elsewhere in China, except in southeast China, where both extreme precipitation and CDD increased. Most of the studied global climate models tend to overestimate extreme precipitation amounts but underestimate CDD. The pattern of precipitation extremes is generally well captured in western China, while in eastern China, where the combination of the monsoon system and human activities (e.g., anthropogenic changes in land use and aerosols) affects climate variation, with the result that climate patterns are reproduced poorly by comparison. In regard to temperature-related extremes, the variation in the occurrence of winter cold surges in southeast China for the period from 1961 to 2005 is investigated. The identified cold surges are divided into 5 different groups based on the evolution pattern of the Siberian High (SH). Associated evolutions of the large-scale atmospheric circulation are investigated. Results suggest the importance of a SH amplification and pre-existing specific synoptic systems to the occurrence of cold surges. Investigating the long-term changes in cold surges of different groups, it is found that the SH-related cold surges (33%) have decreased in the last 20 years, while cold surges more closely associated with background atmospheric circulation systems, which often have a larger impact area (i.e., stronger cold air outbreak) than the SH-related ones, have increased since the early 1980s. Although the intensity of SH was relatively weak with warmer surface air temperatures over China during the period from 1980 to 2005, the total number of cold surges in this period was nearly identical to that of previous decades. This implies that future occurrences of cold surges in southeast China may remain at current levels, provided that the contribution from the SH-related surges does not change dramatically

Tropical cyclone rainfall in the Mekong River Basin for 1983–2016

As home to about 70 million people, the Mekong River Basin (MRB), located in Mainland Southeast Asia, is often influenced by tropical cyclones (TCs) landfalling. The TCs not only cause flood and storm hazards, but also play important roles in providing freshwater resource and welcomed sediment transports. Our study focuses on the climatology of TCs and associated rainfall (TCR) in the MRB for 1983–2016. Results show that: (i) the mean landfall occurrence of TCs is 6.2 yr−1, leading to 36.7 mm yr−1 of annual mean TCR (2.5% of the annual total precipitation), which mainly occur in monsoon-TC season (i.e., June–November); (ii) TCs highly concentrate on the lower eastern MRB, generating the largest TCR contribution of 12.4% to the annual total precipitation; (iii) the annual mean contribution of TCs induced extreme precipitation - R20mm and R50mm (days of heavy precipitation rate ≥20 mm day−1 and ≥50 mm day−1, respectively) - to that from annual total precipitation is large in the lower eastern MRB; (iv) over 60% of the basin area is influenced by TCR on average; and (v) a significant weakening trend of the TC frequency has been observed. The present findings lay a foundation for further in-depth research of the potential influence of the dynamic TCs and the associated rainfall in the MRB.This research was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDA20060401); the China Scholarship Council; the National Natural Science Foundation of China (Grant No. 91537210); Swedish STINT (Grant No. CH2015–6226); the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement (Grant No. 703733); and the Swedish VR (Grant No. 2017-03780)

Molecular Simulation of Adsorption in Deep Marine Shale Gas Reservoirs

Deep marine shale gas reservoirs are extremely rich in the Sichuan basin in China. However, due to the in situ conditions with high temperature and high pressure (HTHP), in particular reservoir pressure being usually much higher than the test pressure, it is difficult to accurately clarify the adsorption behavior, as seepage theory plays an important role in shale gas reserves evaluation. Therefore, three kinds of sorbent, including illite, quartz and kerogen, and two simulation methods, containing the grand canonical ensemble Monte Carlo method and molecular dynamics method, are synthetically used to determine the methane adsorption behavior under HTHP. The results show that both absolute adsorption and excess adsorption decrease with the increase of temperature. When the pressure increases, the absolute adsorption increases quickly and then slowly, and the excess adsorption first increases and then decreases. The superposition of wall potential energy is strongest in a circular hole, second in a square hole, and weakest in a narrow slit. The effect of pore size increases with the decrease of the pore diameter. Under HTHP, multi-layer adsorption can occur in shale, but the timing and number of layers are related to the sorbent type

Spectral analysis of weekly variation in PM10 mass concentration and meteorological conditions over China

This study investigates the region-dependent anthropogenic weekly variation in air pollutants and its relationship with the meteorological conditions over China for the summers of 2001-2005. Spectral analysis was applied to the local daily observations of PM10 (aerosol particulate matter with a diameter < 10 mu m) mass concentrations and precipitation from 31 ground stations, reanalysis estimates of regional atmospheric variables, and satellite retrievals of clouds. Our analysis shows that the 6-8-day variance of PM10 concentrations from the periodogram is closely correlated with the mean PM10 concentration, which may depend on the size (population) and geographical setting of a city, its prevailing climatic conditions, and the type/degree of human activities. We define normalized variance as the ratio of the 6-8-day to 2-14-day variance of PM10 concentrations, possibly indicating the relative anthropogenic signal to the noise of natural weather variability. The normalized variance of PM10 concentrations has a distinct regional rainfall distribution from that of the mean PM 10 concentration in China. As compared to regions with lower normalized variance of PM 10 concentrations, the regions with higher normalized variance generally show higher normalized variance of rainfall events, 1000 hPa wind speeds, sea-level pressure, size spectrum and phase of cloud particles, cloud optical depth, and cloud top pressure. Our results confirm the presence of the interaction between PM 10 and the meteorological conditions in the boundary layer, and suggest a possible link of cloud formation to PM10 on a weekly scale.close353

Correction: Nutrient element-based bioceramic coatings on titanium alloy stimulating osteogenesis by inducing beneficial osteoimmmunomodulation

Correction for ‘Nutrient element-based bioceramic coatings on titanium alloy stimulating osteogenesis by inducing beneficial osteoimmmunomodulation’ by Zetao Chen et al., J. Mater. Chem. B, 2014, 2, 6030–6043