From Security to Assurance in the Cloud Ardagna, Claudio A; Asal, Rasool; Damiani, Ernesto ...
ACM computing surveys,
09/2015, Letnik:
48, Številka:
1
Journal Article
Recenzirano
The cloud computing paradigm has become a mainstream solution for the deployment of business processes and applications. In the public cloud vision, infrastructure, platform, and software services ...are provisioned to tenants (i.e., customers and service providers) on a pay-as-you-go basis. Cloud tenants can use cloud resources at lower prices, and higher performance and flexibility, than traditional on-premises resources, without having to care about infrastructure management. Still, cloud tenants remain concerned with the cloud's level of service and the nonfunctional properties their applications can count on. In the last few years, the research community has been focusing on the nonfunctional aspects of the cloud paradigm, among which cloud security stands out. Several approaches to security have been described and summarized in general surveys on cloud security techniques. The survey in this article focuses on the interface between cloud security and cloud security assurance. First, we provide an overview of the state of the art on cloud security. Then, we introduce the notion of cloud security assurance and analyze its growing impact on cloud security approaches. Finally, we present some recommendations for the development of next-generation cloud security and assurance solutions.
Photocatalytic activity is a feasible solution to tackle environmental pollution caused by industrial pollutants. In this research, Ti3C2–TiO2 composite with a unique structure was fabricated ...successfully via a hydrothermal method. Especially, the in-situ transformation of TiO2 from Ti3C2 MXene creates an intimate heterostructure, which leads to prolonging separation and migration of charged carriers. Thus, this Ti3C2–TiO2 composite enhances effectively methyl orange (MO) degradation efficiency (around 99%) after 40 light-exposed minutes. Besides, the optimal concentration of MO solution was estimated at 40 mg/L and Ti3C2–TiO2 photocatalyst also exhibited good stability after five runs. Moreover, the radical trapping test and the MO photodegradation mechanism over Ti3C2–TiO2 system were also demonstrated. This research illustrates the potential of MXenes as effective co-catalysts for photocatalysis and extends the applications of two-dimensional materials.
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•Ti3C2–TiO2 heterostructure is synthesized from Ti3C2 by hydrothermal oxidation.•In-situ transformation of TiO2 leads to obtain Ti3C2–TiO2 heterostructures.•Ti3C2–TiO2 photocatalyst exhibits a significant efficiency for MO degradation.•The proposed MO photocatalytic mechanism toward Ti3C2–TiO2 composite is illustrated.
Rheumatoid arthritis (RA) is an autoimmune disease that causes pain and tissue destruction in people worldwide. An accurate diagnosis is paramount in order to develop an effective treatment plan. ...This study demonstrates that combining near infrared (NIR) imaging and 19F MRI with the injection of labelled nanoparticles provides high diagnostic specificity for RA. The nanoparticles were made from poly(ethylene glycol)-block-poly(lactic-co-glycolic acid) (NP) or PLGA-PEG-Folate (Folate-NP), loaded with perfluorooctyl bromide (PFOB) and indocyanine green (ICG) and evaluated in vitro and in a collagen-induced arthritic (CIA) mouse model. The different particles had a similar size and a spherical shape according to dynamic light scattering (DLS) and transmission electron microscopy (TEM). Based on flow cytometry and 19F MRI analysis, Folate-NP yielded a higher uptake than NP in activated macrophages in vitro. The potential RA-targeting ability of the particles was studied in CIA mice using NIR and 19F MRI analysis. Both NP and Folate-NP accumulated in the RA tissues, where they were visible in NIR and 19F MRI for up to 24 hours. The presence of folate as a targeting ligand significantly improved the NIR signal from inflamed tissue at the early time point (2 hours), but not at later time points. Overall, these results suggest that our nanoparticles can be applied for combined NIR and 19F MRI imaging for improved RA diagnosis.
This study aims to elucidate whether switching from business households to enterprises brings higher financial performance than not switching. The study was carried out in Thanh Hoa province, ...Vietnam. Our sample includes 366 establishments that were originally business households. Of which, 184 business households switched to enterprises (switchers), and 182 remained as business households (non-switchers). Using propensity score matching, we discovered several exciting findings. First, switching to enterprises has a positive impact on the financial performance of the switchers. Second, applying different matching algorithms, we found that business households that switched to enterprises have higher financial performance than those which did not, with an average increase in ROA from 0.134 to 0.164. Finally, our research findings suggest that provincial leaders and the Vietnamese government should encourage business households to switch to enterprises. In particular, leaders should focus on training programs, loan support, and strengthening support services from the government.
Photocatalytic hydrogen (H2) generation derived by water has been considered as a renewable energy to solve environmental problems and global energy crises. Thus, it is necessary to explore the most ...effective photocatalysts by using multi-cocatalysts, due to an intimate interaction between different components. Therefore, we already synthesized the TiO2/Ti3C2/g-C3N4 (TTC) photocatalyst from g-C3N4 and Ti3C2 MXene via a calcination technique, and applied this composite for H2 evolution. By making use of titanium atom from Ti3C2 MXene, titanium dioxide (TiO2) was in-body developed, which leads to form a close heterostructure between metallic material and semiconductors. Besides, g-C3N4 amorphous with highly surface area also contributes to harvest light irradiation during photocatalytic activity. The optimized TTC-450 heterostructure showed a super H2 generation efficiency than those of pure g-C3N4 and other samples. Besides, TTC-450 sample also exhibited great recyclability after 4 runs. The proposed mechanism illustrates the efficient movement of generated electrons in TTC system, which leads to high H2 evolution efficiency. Moreover, the obtained results consistently emphasize the TiO2/Ti3C2/g-C3N4 composite would be a unique material for H2 production and broaden applications of MXene materials.
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•TiO2/Ti3C2/g-C3N4 ternary composites are prepared via a calcination method.•Ti3C2 MXenes are used as a precursor for in situ transformation of TiO2 phases.•TiO2/Ti3C2/g-C3N4 photocatalyst exhibits a remarkable H2 evolution performance.•A proposed mechanism for H2 evolution toward TiO2/Ti3C2/g-C3N4 was illustrated.
Contrast agents have been widely used in medicine to enhance contrast in magnetic resonance imaging (MRI). Among them, super paramagnetic iron oxide nanoparticles (SPION) have been reported to have ...low risk in clinical use. In our study, F127-Folate coated SPION was fabricated in order to efficiently target tumors and provide imaging contrast in MRI. SPION alone have an average core size of 15 nm. After stabilizing with Pluronic F127, the nanoparticles reached a hydrodynamic size of 180 nm and dispersed well in various kinds of media. The F127-Folate coated SPION were shown to specifically target folate receptor expressing cancer cells by flow cytometry analysis, confocal laser scanning microscope, as well as in vitro MRI. Furthermore, in vivo MRI images have shown the enhanced negative contrast from the F127-Folate coated SPION in tumor-bearing mice. In conclusion, our F127-Folate coated SPION have shown great potential as a contrast agent in MRI, as well as in the combination with drug delivery for cancer therapy.
Polymer coating has drawn increasing attention as a leading strategy to overcome the drawbacks of superparamagnetic iron oxide nanoparticles (SPIONs) in targeted delivery of anticancer drugs. In this ...study, SPIONs were modified with heparin-Poloxamer (HP) shell to form a SPION@HP core-shell system for anticancer drug delivery. The obtained formulation was characterized by techniques including transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR), vibration sample magnetometer (VSM), proton nuclear magnetic resonance (¹H-NMR), and powder X-ray diffraction (XRD). Results showed the successful attachment of HP shell on the surface of SPION core and the inability to cause considerable effects to the crystal structure and unique magnetic nature of SPION. The core-shell system maintains the morphological features of SPIONs and the desired size range. Notably, Doxorubicin (DOX), an anticancer drug, was effectively entrapped into the polymeric shell of SPION@HP, showing a loading efficiency of 66.9 ± 2.7% and controlled release up to 120 h without any initial burst effect. Additionally, MTT assay revealed that DOX-loaded SPION@HP exerted great anticancer effect against HeLa cells and could be safely used. These results pave the way for the application of SPION@HP as an effective targeted delivery system for cancer treatment.
Pharmaceutical manufacturers in Vietnam are producing a wide variety of antibiotics for human and veterinary use. Consequently, the water discharged from those facilities can contain residues of ...antibiotics, which could have adverse impact on the environment. However, studies on the occurrence of antibiotics in the wastewater from pharmaceutical manufacturers in Vietnam are almost non-existent. In this study, water samples were collected at around the outlets of four pharmaceutical manufacturing plants as well as from a hospital and an aquaculture farm around Hanoi in 2016 and 2017. Fifteen antibiotics from four major classes (β-lactam, quinolones, macrolides, sulfonamides) were monitored, using a validated LC-MS/MS method, based on their number of registrations at the Ministry of Health. Ten antibiotics, ampicillin, cefuroxime, cefotaxime, clarithromycin, azithromycin, sulfamethoxazole, trimethoprim, ofloxacin, norfloxacin, and ciprofloxacin were detected in the samples at different concentrations. Notably, sulfonamides and quinolones were occasionally detected at very high concentration, such as sulfamethoxazole (252 μg/L), trimethoprim (107 μg/L), ofloxacin (85 μg/L), and ciprofloxacin (41 μg/L). In this study, concentrations of antibiotic residues in effluent of pharmaceutical plants were higher than those from other sources. The antibiotic-resistance tests indicated the widespread resistance to common antibiotics like quinolone and sulfonamides in the collected samples. This finding suggests that wastewater from pharmaceutical manufacturers could be an important source of antibiotics and antibiotic-resistant bacteria in the aquatic environment of Vietnam.
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•First study on antibiotics discharged from pharmaceutical manufacturer in Vietnam•Results were higher compared with those from hospital and aquaculture effluents.•Pharmaceutical manufacturing is an important source of antibiotics in open waters.•Ubiquitous presence of bacteria resistant to popular antibiotics in the samples
A nanocurcuminoids emulsion (NCE) was successfully synthesized via the phase inversion temperature (PIT) method combining magnetic stirring. Factors affecting the fabrication of this material, ...including emulsifier concentration, types of oils, temperature, and stirring time, were investigated. Results showed that the synthesized efficiency obtained 94.56 ± 3.78% at 11% of emulsifier concentration, 2% of sacha inchi oil with 5,000 rpm of shaking speed within 25 min of reaction time at 80°C. Besides, dynamic light scattering analysis presents that NCE gets 24.1 ± 2.9 nm of the average diameter, −10.4 ± 0.8 mV of zeta potential (ZP), and 0.173 ± 0.021 a.u of the polydispersity index (PDI) at the optimal condition. Moreover, the prepared NCE was stable at the ionic strength of NaCl 0.5 M and pH of 7 after 60 days of storage. In particular, the antioxidant activity of this NCE was slightly higher than that of free curcuminoids.
Practical applications
The mixture, including NCE 12%, maltose 58%, honey 12%, and water, was homogenized at a rate of 10,000 rpm in 15 min. Afterward, the system was condensed by a vacuum rotary evaporator (Yamato RE301 vacuum rotary evaporator) at 60°C in 30 min to obtain the Instant Beverage Jam. The obtained products showed a moderate sweetness and retained the characteristic taste of curcumin.
•Coexistence of ZnO and Co3O4 in Co3O4-ZnO nanoparticle from the bi metal-organic framework.•The formation of p-n nano-heterojunctions and the transition of electrons from Co3O4 to ZnO.•Entire ...degradation of MO by Co3O4-ZnO NPs for 120 min under solar light.•Significant stability and recyclability for four catalytic cycles of Co3O4-ZnO NPs.
Herein, we prepared the in-situ CoZn-Metal-Organic Framework (MOF) nanoparticles (NPs) and converted them into bi-oxide metal Co3O4-ZnO nano-size by calcination. Under solar light, both Co3O4 and ZnO are excited about having electrons and holes. The photogenerated electrons passed from the conductive Co3O4 band to the ZnO band, react to adsorbed oxygen molecules and water to produce superoxide radical anions like ·O2−, and OH−. In the meantime, H2O and OH− trap the exciting holes on to yield OH−, and OH species and entirely degraded methyl orange (MO) under solar light after 120 min. Co3O4-ZnO NPs photocatalyst displayed significant stability and recyclability for four catalytic cycles.
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