HASG: Security and Efficient Frame for Accessing Cloud Storage

StaaS(Storage as a Service) has been envisioned as the next generation architecture of IT enterprise. Enterprise, individual end users move more and more important information to outsourced data centers, where the data may be misappropriated in the malicious model. Moreover, users hesitate to store data in the cloud storage because of network fluctuation. Security and availability become the main concern of cloud storage. This paper, to address these issues, presents an architecture of High Available cloud Storage Gateway(HASG). In our design, data file is divided into implicit, redundant blocks by file fragment algorithm. Part of these blocks, which are stored on different designated cloud servers, can be used to reconstruct original file. Additionally, dynamic service provider selection algorithm and redundant block mechanism for file updating is proposed to effectuate cost and bandwidth savings and accelerate data accessing. Experimental results illustrates that our design enhanced security of cloud storage and improved data access efficiency.

DCC: Distributed Cache Consistency

Replicating caches across distributed nodes to convert remote data transferred for local data reading, are widely used to reduce latency for applications and enhance storage availability in a distributed software system. DCC (Distributed Cache Consistency) is an mixed geo-replicated protocol to allow consistency of distributed caches by properly the relaxing read-write constraint.DCC reduces the number of required message round-trips in synchronization by taking advantage of a combination of Fast Paxos and Lease. At the same time, a lease protocol and a local synchronization group is used to reduce the message transmission and collision probability. A simple calculation model is set up to predict the performance of the model and analyze the potential application fieldsof DCC. The results, based on actual system observation parameters, show that DCC meets different consistency requirements for a distributed cache in scalable applications by adjustment of configuration parameters.

Have Industrial Robots Improved Pollution Reduction?A Theoretical Approach and Empirical Analysis

To investigate whether industrial robots have improved the ecological environment,this study integrated the adoption of robot technology and pollution abatement into Melitz's heterogeneous firm model.This showed that using robots in production can lower firms'pollution intensity by increasing their abatement investments,and this reduction effect is greater for higher polluting firms and those subject to weaker local environmental regulations.These theoretical expectations were then confirmed through a series of empirical investigations based on Bartik instrument regressions,with multiple robustness checks as well as heterogeneity and mechanism analyses.This paper adds to the literature on the relationships between automation technologies and green transformation.It shows that in the pursuit of economic growth and environmental protection,it is necessary for policymakers to shift from pollution control to technical support for traditional manufacturing firms.

Polyoxypregnanes as safe, potent, and specific ABCB1-inhibitory pro-drugs to overcome multidrug resistance in cancer chemotherapy in vitro and in vivo

Multidrug resistance(MDR)mediated by ATP binding cassette subfamily B member 1(ABCB1)is significantly hindering effective cancer chemotherapy.However,currently,no ABCB1-inhibitory drugs have been approved to treat MDR cancer clinically,mainly due to the inhibitor specificity,toxicity,and drug interactions.Here,we reported that three polyoxypregnanes(POPs)as the most abundant constituents of Marsdenia tenacissima(M.tenacissima)were novel ABCB1-modulatory pro-drugs,which underwent intestinal microbiota-mediated biotransformation in vivo to generate active metabolites.The metabolites at non-toxic concentrations restored chemosensitivity in ABCB1-overexpressing cancer cells via inhibiting ABCB1 efflux activity without changing ABCB1 protein expression,which were further identified as specific non-competitive inhibitors of ABCB1 showing multiple binding sites within ABCB1 drug cavity.These POPs did not exhibit ABCB1/drug metabolizing enzymes interplay,and their repeated administration generated predictable pharmacokinetic interaction with paclitaxel without obvious toxicity in vivo.We further showed that these POPs enhanced the accumulation of paclitaxel in tumors and overcame ABCB1-mediated chemoresistance.The results suggested that these POPs had the potential to be developed as safe,potent,and specific pro-drugs to reverse ABCB1-mediated MDR.Our work also provided scientific evidence for the use of M.tenacissima in combinational chemotherapy.

Preparation, Crystal Structure and Properties of a New Crystal Form of Diammonium 5,5＇-bistetrazole-1,1＇-diolate

A new crystal form of diammonium 5,5＇-bistetrazole-1,1＇-diolate （1） was prepared by two novel methods and fully characterized by using IR, NMR spectroscopy, elementary analysis, single crystal X-ray crystallography and thermal gravity/differential thermal analysis （TG/DTA）. Crystalline 1 was found as monoclinic and space group of P21/c （14）. The TG/DTA analysis showed that the decomposition temperature of 1 was 287.8℃ with a mass loss of 91.2% in the range of 220-300℃ at a heating rate of 5℃/min. The sensitivities test towards impact, friction of 1 indicated that 1 has much lower sensitivities than those of RDX/HMX and is comparable to those of TNT, which suggested that 1 could be used as a good candidate of new insensitive energetic compound.