An Internet-wide Penetration Study on NAT Boxes via TCP/IP Side Channel

Network Address Translation (NAT) plays an essential role in shielding devices inside an internal local area network from direct malicious accesses from the public Internet. However, recent studies show the possibilities of penetrating NAT boxes in some specific circumstances. The penetrated NAT box can be exploited by attackers as a pivot to abuse the otherwise inaccessible internal network resources, leading to serious security consequences. In this paper, we aim to conduct an Internet-wide penetration testing on NAT boxes. The main difference between our study and the previous ones is that ours is based on the TCP/IP side channels. We explore the TCP/IP side channels in the research literature, and find that the shared-IPID side channel is the most suitable for NAT-penetration testing, as it satisfies the three requirements of our study: generality, ethics, and robustness. Based on this side channel, we develop an adaptive scanner that can accomplish the Internet-wide scanning in 5 days in a very non-aggressive manner. The evaluation shows that our scanner is effective in both the controlled network and the real network. Our measurement results reveal that more than 30,000 network middleboxes are potentially vulnerable to NAT penetration. They are distributed across 154 countries and 4,146 different organizations, showing that NAT-penetration poses a serious security threat

FUS-NLS/Transportin 1 complex structure provides insights into the nuclear targeting mechanism of FUS and the implications in ALS

The C-terminal nuclear localization sequence of FUsed in Sarcoma (FUS-NLS) is critical for its nuclear import mediated by transportin (Trn1). Familial amyotrophic lateral sclerosis (ALS) related mutations are clustered in FUS-NLS. We report here the structural, biochemical and cell biological characterization of the FUS-NLS and its clinical implications. The crystal structure of the FUS-NLS/Trn1 complex shows extensive contacts between the two proteins and a unique α-helical structure in the FUS-NLS. The binding affinity between Trn1 and FUS-NLS (wide-type and 12 ALS-associated mutants) was determined. As compared to the wide-type FUS-NLS (K(D) = 1.7 nM), each ALS-associated mutation caused a decreased affinity and the range of this reduction varied widely from 1.4-fold over 700-fold. The affinity of the mutants correlated with the extent of impaired nuclear localization, and more importantly, with the duration of disease progression in ALS patients. This study provides a comprehensive understanding of the nuclear targeting mechanism of FUS and illustrates the significance of FUS-NLS in ALS

Effects of detection-beam focal offset on displacement detection in optical tweezers

A high-resolution displacement detection can be achieved by analyzing the scattered light of the trapping beams from the particle in optical tweezers. In some applications where trapping and displacement detection need to be separated, a detection beam can be introduced for independent displacement detection. However, the detection beam focus possibly deviates from the centre of the particle, which will affect the performance of the displacement detection. In this paper, we detect the radial displacement of the particle by utilizing the forward scattered light of the detection beam from the particle. The effects of the lateral and axial offsets between the detection beam focus and the particle centre on the displacement detection are analyzed by the simulation and experiment. The results show that the lateral offsets will decrease the detection sensitivity and linear range and aggravate the crosstalk between the x-direction signal and y-direction signal of QPD. The axial offsets also affect the detection sensitivity, an optimal axial offset can improve the sensitivity of the displacement detection substantially. In addition, the influence of system parameters, such as particle radius a, numerical aperture of the condenser NAc and numerical aperture of the objective NAo on the optimal axial offset are discussed. A combination of conventional optical tweezers instrument and a detection beam provides a more flexible working point, allowing for the active modulation of the sensitivity and linear range of the displacement detection. This work would be of great interest for improving the accuracy of the displacement and force detection performed by the optical tweezers.Comment: 10 pages,11 figure

Characterization of cellulase production by carbon sources in two Bacillus species

The induction of cellulase production in two Bacillus spp. was studied by means of measuring cellulase activities under the condition of different carbon sources. The results indicate that cellulase could not be induced by cellulose material as a sole carbon source. Instead, they could be induced by monosaccharide or disaccharide with reducing group. Moreover, the expression of cellulase components was synergistic. When cell wall/envelope enzyme and endoenzyme from two Bacillus spp. acted on these inducers, analysis of reaction products by high performance liquid chromatography (HPLC) revealed that cell wall/envelope enzyme and endoenzyme from two Bacillus spp. were inactive on these inducers. It also indicated that these inducers entered cells directly and served function of induction.Keywords: Bacillus, cellulase, induction, carbon source

Sampling and Kriging Spatial Means: Efficiency and Conditions

Sampling and estimation of geographical attributes that vary across space (e.g., area temperature, urban pollution level, provincial cultivated land, regional population mortality and state agricultural production) are common yet important constituents of many real-world applications. Spatial attribute estimation and the associated accuracy depend on the available sampling design and statistical inference modelling. In the present work, our concern is areal attribute estimation, in which the spatial sampling and Kriging means are compared in terms of mean values, variances of mean values, comparative efficiencies and underlying conditions. Both the theoretical analysis and the empirical study show that the mean Kriging technique outperforms other commonly-used techniques. Estimation techniques that account for spatial correlation (dependence) are more efficient than those that do not, whereas the comparative efficiencies of the various methods change with surface features. The mean Kriging technique can be applied to other spatially distributed attributes, as well

Structure optimization on the photoelectric and photocatalytic properties of Cu2S and ZnO complex films

Two kinds of multilayer Cu2S/ZnO, ZnO/Cu2S were deposited on glass substrates by means of radio frequency (RF) magnetron sputtering device. The impact of the thickness of ZnO and Cu2S on the whole transmittance, conductivity, and photocatalysis was investigated. The optical and electrical properties of the multilayer were studies by optical spectrometry and four point probes. (C) 2015 Elsevier Ltd. All rights reserved. Selected and peer-review under responsibility of TEMA - Centre for Mechanical Technology and Automation. (C) 2015 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of TEMA - Centre for Mechanical Technology and Automation.NSFC - National Natural Science Foundation of China(61179055)info:eu-repo/semantics/publishedVersio

Turning the Tap: Conformational Control of Quantum Interference to Modulate Single Molecule Conductance

Together with the more intuitive and commonly recognized conductance mechanisms of charge‐hopping and tunneling, quantum interference (QI) phenomena have been identified as important factors affecting charge transport through molecules. Consequently, establishing simple, flexible molecular design strategies to understand, control and exploit QI in molecular junctions poses an exciting challenge. Here we demonstrate that destructive quantum interference (DQI) in meta‐substituted phenylene ethylene‐type oligomers (m‐OPE) can be tuned by changing the position and conformation of pendant methoxy (OMe) substituents around the central phenylene ring. These substituents play the role of molecular‐scale ‘taps’, which can be switched on or off to control the current flow through a molecule. Our experimental results conclusively verify recently postulated magic ratio and orbital product rules, and highlight a novel chemical design strategy for tuning and gating DQI features, to create single‐molecule devices with desirable electronic functions