bluuebunny/crossref_metadata_2025 huggingface dataset:
From Yellowstone to Australia and New Zealand: National Parks 2.0
Authors: Frost Warwick , Laing Jennifer
Published: May 2016

Following the establishment of the world's first national park at Yellowstone (USA) in 1872, the concept was rapidly transferred to Australia, New Zealand and Canada. This article examines this second wave of adoption – and adaption – focussing on five case studies from Australia and New Zealand. While Yellowstone provided the inspiration for further national parks and protected areas, what was developed was often very different from the American template. Some of these national parks were quite small and some primarily orientated towards recreation. The New Zealand examples were profoundly shaped by interactions with the indigenous peoples, whereas the Australian ones were not. By early in the twentieth century, this second wave was beginning to focus on protecting specific ecosystems and wildlife, developments well in advance of the USA at that time. In taking the Yellowstone model and greatly adapting it for a variety of different social, political and physical environments, this second wave laid the foundations for the internationalisation of the national parks concept.
Optimizing mix-zone coverage in pervasive wireless networks
Authors: Jadliwala Murtuza , Bilogrevic Igor , Hubaux Jean-Pierre
Published: May 2016

Location privacy is a major concern in pervasive networks where static device identifiers enable malicious eavesdroppers to continuously track users and their movements. In order to prevent such identifier-based tracking, devices could coordinate regular identifier change operations in special areas called mix-zones. Although mix-zones provide spatio-temporal de-correlation between old and new identifiers, depending on the position of the mix-zone, identifier changes can generate a substantial inconvenience (or “cost”) to the users in terms of lost communications and increased energy consumption. In this paper, we address this trade-off between privacy and cost by studying the problem of determining an optimal set of mix-zones such that the degree of mixing in the network is maximized and the overall network-wide mixing cost is minimized. We follow a graph-theoretic approach and model the optimal mixing problem as a generalization of the vertex cover problem, called the Mix Cover (MC) problem. We propose three approximation algorithms for the MC problem and derive a lower bound on the solution quality guaranteed by them. Additionally, we outline two other heuristics for solving the MC problem. These heuristics are simple, but do not provide any guarantees on the solution quality. By means of extensive empirical evaluation using real data, we compare the performance and solution quality of these algorithms. The combinatorics-based approach used in this work enables us to study the feasibility of determining optimal mix-zones regularly and under dynamic network conditions.
Dynamic enforcement of knowledge-based security policies using probabilistic abstract interpretation
Authors: Mardziel Piotr , Magill Stephen , Hicks Michael , Srivatsa Mudhakar
Published: May 2016

This paper explores the idea of knowledge-based security policies, which are used to decide whether to answer queries over secret data based on an estimation of the querier's (possibly increased) knowledge given the results. Limiting knowledge is the goal of existing information release policies that employ mechanisms such as noising, anonymization, and redaction. Knowledge-based policies are more general: they increase flexibility by not fixing the means to restrict information flow. We enforce a knowledge-based policy by explicitly tracking a model of a querier's belief about secret data, represented as a probability distribution, and denying any query that could increase knowledge above a given threshold. We implement query analysis and belief tracking via abstract interpretation, which allows us to trade off precision and performance through the use of abstraction. We have developed an approach to augment standard abstract domains to include probabilities, and thus define distributions. We focus on developing probabilistic polyhedra in particular, to support numeric programs. While probabilistic abstract interpretation has been considered before, our domain is the first whose design supports sound conditioning, which is required to ensure that estimates of a querier's knowledge are accurate. Experiments with our implementation show that several useful queries can be handled efficiently, particularly compared to exact (i.e., sound) inference involving sampling. We also show that, for our benchmarks, restricting constraints to octagons or intervals, rather than full polyhedra, can dramatically improve performance while incurring little to no loss in precision.
An optimization framework for role mining
Authors: Lu Haibing , Vaidya Jaideep , Atluri Vijayalakshmi
Published: May 2016

Role Based Access Control (RBAC) is accepted as the de facto access control model for organizations of all sizes. However, engineering the right set of roles is crucial to enable the correct deployment of RBAC within an organization. Indeed, discovering an optimal and correct set of roles from existing permission assignments, referred to as the role mining problem (RMP), has gained significant attention in recent years. Role Mining is itself an instantiation of Boolean matrix decomposition – wherein a Boolean matrix is decomposed into two Boolean matrices giving a set of basis vectors and their appropriate combination. In fact, such decompositions are useful in a number of application domains beyond role engineering, including text mining as well as knowledge discovery. While a Boolean matrix can be decomposed in many ways, however, certain decompositions better characterize the semantics associated with the original matrix in a succinct but comprehensive way. Indeed, one can find different decompositions that are optimal with respect to different criteria that may match various semantics. In this paper, we first present a number of variants of the optimal Boolean matrix decomposition problem, including usage RMP, basic RMP, δ-approximate RMP, and edge RMP, that have pragmatic implications in the context of role mining. We then present a unified framework for modeling the optimal Boolean matrix decomposition and its variants using integer linear programming (ILP). Such modeling allows us to directly adopt the huge body of heuristic solutions and tools developed for integer linear programming. We also develop efficient heuristics and solutions for each RMP variant, and validate them by a comprehensive experimental evaluation.
A game-theoretic analysis of preventing spam over Internet Telephony via audio CAPTCHA-based authentication
Authors: Soupionis Yannis , Koutsiamanis Remous-Aris , Efraimidis Pavlos , Gritzalis Dimitris
Published: May 2016

Spam over Internet Telephony (SPIT) is a potential source of disruption in Voice over IP (VoIP) systems. The use of anti-SPIT mechanisms, such as filters and audio CAPTCHA (Completely Automated Public Turing Test to Tell Computer and Humans Apart) can prevent unsolicited calls and lead to less unwanted traffic. In this paper, we present a game-theoretic model, in which the game is played between SPIT senders and internet telephony users. The game includes call filters and audio CAPTCHA, so as to classify incoming calls as legitimate or malicious. We show how the resulting model can be used to decide upon the trade-offs present in this problem and help us predict the SPIT sender’s behavior. We also highlight the advantages in terms of SPIT call reduction of merely introducing CAPTCHA, and provide experimental verification of our results.
The generalized temporal role mining problem
Authors: Mitra Barsha , Sural Shamik , Atluri Vijayalakshmi , Vaidya Jaideep
Published: May 2016

Role mining, the process of deriving a set of roles from the available user-permission assignments, is considered to be an essential step in successful implementation of Role-Based Access Control (RBAC) systems. Traditional role mining techniques, however, are not equipped to handle temporal extensions of RBAC like the Temporal-RBAC (TRBAC) model. In this paper, we formally define the problem of finding a minimal set of roles from temporal user-permission assignments, such that in the resulting TRBAC system, users acquire either the same or a subset of the permissions originally assigned to them for the complete or partial durations of time as specified in the input. We show that the problem is NP-complete and propose a greedy algorithm for solving it. Our algorithm first derives a set of candidate roles from the temporal user-permission assignments and then selects the least possible number of roles from the candidate role set. The final output consists of a set of roles, a user-to-role assignment relation, a role-to-permission assignment relation and a role enabling base describing the time durations for which each role is enabled. Performance of the proposed approach has been evaluated on a number of synthetic as well as real-world datasets.
Loose associations to increase utility in data publishing
Authors: De Capitani di Vimercati Sabrina , Foresti Sara , Jajodia Sushil , Livraga Giovanni , Paraboschi Stefano , Samarati Pierangela
Published: May 2016

Data fragmentation has been proposed as a solution for protecting the confidentiality of sensitive associations when releasing data for publishing or external storage. To enrich the utility of data fragments, a recent approach has put forward the idea of complementing a pair of fragments with some (non-precise, hence loose) information on the association between them. Starting from the observation that in presence of multiple fragments the publication of several independent associations between pairs of fragments can cause improper leakage of sensitive information, in this paper we extend loose associations to operate over an arbitrary number of fragments.

We first illustrate how the publication of multiple loose associations between different pairs of fragments can potentially expose sensitive associations, and describe an approach for defining loose associations among an arbitrary set of fragments. We investigate how tuples in fragments can be grouped for producing loose associations so to increase the utility of queries executed over fragments. We then provide a heuristics for performing such a grouping and producing loose associations satisfying a given level of protection for sensitive associations, while achieving utility for queries over different fragments. We also illustrate the result of an extensive experimental effort over both synthetic and real datasets, which shows the efficiency and the enhanced utility provided by our proposal.
Anonymizing transactional datasets
Authors: AL Bouna Bechara , Clifton Chris , Malluhi Qutaibah
Published: May 2016

In this paper, we study the privacy breach caused by unsafe correlations in transactional data where individuals have multiple tuples in a dataset. We provide two safety constraints to guarantee safe correlation of the data: (1) the safe grouping constraint to ensure that quasi-identifier and sensitive partitions are bounded by l-diversity and (2) the schema decomposition constraint to eliminate non-arbitrary correlations between non-sensitive and sensitive values to protect privacy and at the same time increase the aggregate analysis. In our technique, values are grouped together in unique partitions that enforce l-diversity at the level of individuals. We also propose an association preserving technique to increase the ability to learn/analyze from the anonymized data. To evaluate our approach, we conduct a set of experiments to determine the privacy breach and investigate the anonymization cost of safe grouping and preserving associations.
Multilevel secure transaction processing
Authors: Jajodia Sushil , Atluri Vijayalakshmi , Keefe Thomas F. , McCollum Catherine D. , Mukkamala Ravi
Published: May 2016

Since 1990, transaction processing in multilevel secure database management systems (DBMSs) has been receiving a great deal of attention from the security community. Transaction processing in these systems requires modification of conventional scheduling algorithms and commit protocols. These modifications are necessary because preserving the usual transaction properties when transactions are executing at different security levels often conflicts with the enforcement of the security policy. Considerable effort has been devoted to the development of efficient, secure algorithms for the major types of secure DBMS architectures: kernelized, replicated, and distributed. An additional problem that arises uniquely in multilevel secure DBMSs is that of secure, correct execution when data at multiple security levels must be written within one transaction. Significant progress has been made in a number of these areas, and a few of the techniques have been incorporated into commercial trusted DBMS products. However, there are many open problems remain to be explored. This paper reviews the achievements to date in transaction processing for multilevel secure DBMSs. The paper provides an overview of transaction processing needs and solutions in conventional DBMSs as background, explains the constraints introduced by multilevel security, and then describes the results of research in multilevel secure transaction processing. Research results and limitations in concurrency control, multilevel transaction management, and secure commit protocols are summarized. Finally, important new areas are identified for secure transaction processing research.
A process-algebraic approach for the analysis of probabilistic noninterference
Authors: Aldini Alessandro , Bravetti Mario , Gorrieri Roberto
Published: May 2016

We define several security properties for the analysis of probabilistic noninterference as a conservative extension of a classical, nondeterministic, process-algebraic approach to information flow theory. We show that probabilistic covert channels (that are not observable in the nondeterministic setting) may be revealed through our approach and that probabilistic information can be exploited to give an estimate of the amount of confidential information flowing to unauthorized users. Finally, we present a case study showing that the expressiveness of the calculus we adopt makes it possible to model and analyze real concurrent systems.
A comparison between strand spaces and multiset rewriting for security protocol analysis
Authors: Cervesato Iliano , Durgin Nancy A. , Lincoln Patrick D. , Mitchell John C. , Scedrov Andre
Published: May 2016

Formal analysis of security protocols is largely based on a set of assumptions commonly referred to as the Dolev–Yao model. Two formalisms that state the basic assumptions of this model are related here: strand spaces and multiset rewriting with existential quantification. Strand spaces provide a simple and economical approach to analysis of completed protocol runs by emphasizing causal interactions among protocol participants. The multiset rewriting formalism provides a very precise way of specifying finite-length protocols with unboundedly many instances of each protocol role, such as client, server, initiator, or responder. A number of modifications to each system are required to produce a meaningful comparison. In particular, we extend the strand formalism with a way of incrementally growing bundles in order to emulate an execution of a protocol with parametric strands. The correspondence between the modified formalisms directly relates the intruder theory from the multiset rewriting formalism to the penetrator strands. The relationship we illustrate here between multiset rewriting specifications and strand spaces thus suggests refinements to both frameworks, and deepens our understanding of the Dolev–Yao model.
Risk management for distributed authorization
Authors: Skalka Christian , Wang X. Sean , Chapin Peter
Published: May 2016

Distributed authorization takes into account several elements, including certificates that may be provided by non-local actors. While most trust management systems treat all assertions as equally valid up to certificate authentication, realistic considerations may associate risk with some of these elements, for example some actors may be less trusted than others. Furthermore, practical online authorization may require certain levels of risk to be tolerated. In this paper, we introduce a trust management logic based on the system RT that incorporates formal risk assessment. This formalization allows risk levels to be associated with authorization, and authorization risk thresholds to be precisely specified and enforced. We also develop an algorithm for automatic authorization in a distributed environment, that is directed by risk considerations. A variety of practical applications are discussed.
Configuring storage-area networks using mandatory security
Authors: Aziz Benjamin , Foley Simon N. , Herbert John , Swart Garret
Published: May 2016

Storage-area networks are a popular and efficient way of building large storage systems both in an enterprise environment and for multi-domain storage service providers. In both environments the network and the storage has to be configured to ensure that the data is maintained securely and can be delivered efficiently. In this paper, we describe a model of mandatory security for SAN services that incorporates the notion of risk as a measure of the robustness of the SAN's configuration and that formally defines a vulnerability common in systems with mandatory security, i.e. cascaded threats. Our abstract SAN model is flexible enough to reflect the data requirements, tractable for the administrator, and can be implemented as part of an automatic configuration system. The implementation is given as part of a prototype written in OPL.
Leveraging personal devices for stronger password authentication from untrusted computers
Authors: Mannan Mohammad , van Oorschot P.C.
Published: May 2016

Internet authentication for popular end-user transactions, such as online banking and e-commerce, continues to be dominated by passwords entered through end-user PCs. Most users continue to prefer (typically untrusted) PCs over smaller personal devices for actual transactions, due to usability features related to keyboard and screen size. However, most such transactions and their underlying protocols are vulnerable to attacks including keylogging, phishing and pharming. We propose Mobile Password Authentication (MP-Auth) to counter such attacks, which cryptographically separates a user's long-term secret input from the client PC, and offers transaction integrity. The PC continues to be used for most of the interaction but has access only to temporary secrets, while the user's long-term secret is input through an independent personal device, e.g., a cellphone which makes it available to the PC only after encryption under the intended far-end recipient's public key. MP-Auth expects users to input passwords only to a personal device, and be vigilant while confirming transactions from the device. To facilitate a comparison to MP-Auth, we also provide a comprehensive survey of web authentication techniques that use an additional factor of authentication; this survey may be of independent interest.
Policy-driven role-based access management for ad-hoc collaboration
Authors: Ahn Gail-Joon , Jin Jing , Shehab Mohamed
Published: May 2016

Ad-hoc collaboration is a newly emerged environment enabling distributed collaborators to share resources. The dynamic nature and unique sharing pattern in ad-hoc collaboration poses great challenges for security services to accommodate both access control and trust management requirements in providing controlled resource sharing. In this paper, we propose a comprehensive, integrated and implemented access management framework, called RAMARS, for secure digital information sharing in ad-hoc collaboration. Our framework incorporates a role-based approach to leverage the originator control, delegation and dissemination control. A trust awareness feature is integrated for dynamic user-role assignment based on user attributes. The access control polices are formally specified, and a peer-to-peer scientific information sharing system – ShareEnabler – is presented to demonstrate the feasibility of our approach. The performance evaluation of our prototype system with potential system improvements is also discussed.
Behavior-based access control for distributed healthcare systems
Authors: Yarmand Mohammad H. , Sartipi Kamran , Down Douglas G.
Published: May 2016

Sensitivity of clinical data and strict rules regarding data sharing have caused privacy and security to be critical requirements for using patient profiles in distributed healthcare systems. The amalgamation of new information technology with traditional healthcare workflows for sharing patient profiles has made the whole system vulnerable to privacy and security breaches. Standardization organizations are developing specifications to satisfy the required privacy and security requirements. In this paper we present a novel access control model compliant with healthcare standards based on a framework designed for data and service interoperability in the healthcare domain. The proposed model for customizable access control captures the dynamic behavior of the user and determines access rights accordingly.

The model is generic and flexible in the sense that an access control engine dynamically receives security effective parameters from the subject user, and identifies the privilege level in accessing data using different specialized components within the engine. Standard data representation formats and ontologies are used to make the model compatible with different healthcare systems. The access control engine employs an approach to follow the user's behavior and navigates among engine components to provide the user's privilege to access a resource. A simulation environment is implemented to evaluate and test the proposed model.
Prevalence and intensity of helminth parasites in the snake headed fish, Channa punctatus of Savar, Dhaka
Authors: Sultana Sabira , Salam Md Abdus
Published: May 2016

Ten species of helminth parasites i.e. Neopecoelina saharanpuriensis, Mesolecitha linearis, Asymphylodora tincae, Genarchopsis bangladensis, Ditestolepis diphana, Senga sp., Neoechinorhynchus tylosuri, Pallisentis sp., Ascardia larvae., Gnathostoma spinigerum were identified from Channa punctatus of Savar area. Majority of the parasites were found in the intestine. The overall prevalence of infection of the parasites was 32.5% and the mean intensity was 1.46±1.29. Both the prevalence (34.61%) and mean intensity (1.5±1.21) were higher in male fishes than the female fishes (28.57% and 1.375± 0.99 respectively). The prevalence (13.75%) and mean intensity (1.64± 0.67) of trematodes were the highest among the parasites groups. Both the prevalence and mean intensity were the highest in the intermediate length (10.1-15.1cm) and weight (21-31gm) groups of fishes.Jahangirnagar University J. Biol. Sci. 4(1): 1-7, 2015 (June)
Antidiabetic potential of the leaf extract of Centella asiatica in alloxaninduced diabetic rats
Authors: Emran Talha Bin , Dutta Mycal , Uddin Mir Muhammad Nasir , Nath Aninda Kumar , Uddin Md Zia
Published: May 2016

The study was designed to evaluate the glucose and cholesterol lowering effect of the aqueous extract of Centella asiatica leaf using the alloxan-induced diabetic rats and compared the activity with diabetic control and antidiabetic drug (Glibenclamide). Leaf extract (50 mg/kg) of C. asiatica and Glibenclamide were administered to normal and experimental diabetic rats for the duration of 10 days. In the alloxan-induced diabetic rat model, C. asiatica extract (50 mg/kg) significantly (p < 0.05) lowered the fasting blood glucose level as well as the total cholesterol level. Serum insulin levels were not stimulated in the animals treated with the extract. In addition, changes in body weight, serum lipid profiles and liver glycogen levels assessed in the extract treated diabetic rats were compared with diabetic control and normal animals. Significant results (p < 0.05) were observed in the estimated parameters. Surprisingly, body weight was increased significantly (p < 0.05) in the C. asiatica treated diabetic group. Phytochemical screening showed the presence of alkaloids, flavonoids, glycosides, steroids and tannins in significant amountsJahangirnagar University J. Biol. Sci. 4(1): 51-59, 2015 (June)
Karyomorphology of Centella asiatica (L.) Urban
Authors: Warasy Ashma Ahmed
Published: May 2016

Abstract not availableJahangirnagar University J. Biol. Sci. 4(1): 81-84, 2015 (June)
Effects of perfluorooctane sulfonate on the hematology and histopathology of juvenile tilapia, Oreochromis niloticus
Authors: Billah Md Baki , Paul Sudip , Sultana Sabira , Hasan Md Jahid , Salam Md Abdus
Published: May 2016

Perfluorooctane sulfonate (PFOS), a persistent organic pollutant, biologically stable in the environment and bio-accumulate in the tissues of aquatic animals as well as wildlife and humans. The toxicity of perfluorooctane sulfonate were tested at 1, 3 and 5mg/L concentrations on the juvenile tilapia, Oreochromis niloticus after 7, 15, 30, 45 and 60 days of exposure. The hematological parameters revealed that with the increase in concentrations and exposure time the total count of the RBC, WBC and hemoglobin content were significantly (p<0.05) decreased compared to the control. The histopathological examinations showed that PFOS may induce some changes in kidney and liver. The present results demonstrate that additional research may be conducted to identify the mechanism of perfluorooctane sulfonate toxicityJahangirnagar University J. Biol. Sci. 4(2): 37-45, 2015 (December)
Antiferroelectric Shape Memory Ceramics
Authors: Uchino Kenji
Published: May 2016

Antiferroelectrics (AFE) can exhibit a “shape memory function controllable by electric field”, with huge isotropic volumetric expansion (0.26%) associated with the AFE to Ferroelectric (FE) phase transformation. Small inverse electric field application can realize the original AFE phase. The response speed is quick (2.5 ms). In the Pb0.99Nb0.02[(Zr0.6Sn0.4)1-yTiy]0.98O3 (PNZST) system, the shape memory function is observed in the intermediate range between high temperature AFE and low temperature FE, or low Ti-concentration AFE and high Ti-concentration FE in the composition. In the AFE multilayer actuators (MLAs), the crack is initiated in the center of a pair of internal electrodes under cyclic electric field, rather than the edge area of the internal electrodes in normal piezoelectric MLAs. The two-sublattice polarization coupling model is proposed to explain: (1) isotropic volume expansion during the AFE-FE transformation; and (2) piezoelectric anisotropy. We introduce latching relays and mechanical clampers as possible unique applications of shape memory ceramics.
Impact of Manufacturing Transfer on SO2 Emissions in Jiangsu Province, China
Authors: Peng Ying , Cui Jian , Cao Youhui , Du Ying , Chan Andrew , Yang Fumo , Yang Hao
Published: May 2016

The impact of manufacturing transfer in Jiangsu province, China, on the spatial-temporal variations of SO2 emissions is investigated using estimated sector-specific SO2 emissions, and emissions in the different transfer-in and transfer-out regions were quantified during 2000–2011. Our results show that SO2 emissions had undergone three phases: an increase in the period of 2000–2005, a rapid decline in 2005–2008 and a slow decline in 2008–2011. Emissions from the south dominated the total emissions in the province. Cleaner production generally contributed to the reduced emissions, but rather, at the industrial scale. Pollution abatement was occasional and industrial structure was negligible in some years. The three phases also coincided with the three periods of the manufacturing transfer: transferred to the south from outside the province during 2000–2005, to the central from the south within the province during 2005–2008 and to the north from the south or partly from the inner central within the province during 2008–2011. With the manufacturing transfer, SO2 emission magnitudes and distributions were also changed. In the south, −12.36 and −5.62 Mt of SO2 emissions were transferred out during 2005–2008 and 2008–2011, respectively. Forty-three-point-four percent and 56.4% of the SO2 emissions in the south were transferred to the central and north during 2005–2008, respectively. The north region received 77.7% and 22.1% of SO2 emissions from the south and the central region during 2008–2011, respectively. The paper reveals that structure adjustments should be executed in a timely manner in the manufacturing transfer-in process so that the transfer-in regions can benefit from the economic boom without bearing a deteriorated environment.
Sustainable Development and Corporate Social Responsibility in Sub-Saharan Africa: Evidence from Industries in Cameroon
Authors: Oginni Oyewole , Omojowo Adewale
Published: May 2016

Present technological innovations and social organizations continue to impose risks and limitations on the efficient performance of the biosphere. Human activities have increasingly short-lived sustainable natural endowments, to the extent that, the multiplier effects have ripples beyond the traditional benefits of economic production and consumption. Therefore, this study addressed practical concerns on how industries in Sub-Saharan Africa promote sustainable development in their corporate social responsibility models, using industries in Cameroon as a case study; it examined economic, social, and environmental components of sustainable development and corporate social responsibility (CSR). Our sample consists of 335 business enterprises from the last Censure Survey of Enterprises in Cameroon. The study adopted a systematic analysis through the Adjusted Residual Test, and the Phi and Cramer’s V tests. Findings revealed that industries in Cameroon prioritize environmental and social dimensions over economic dimensions. However, a few large enterprises implement a broad CSR that promotes sustainable business practices, whereas smaller ones do not; industries in Cameroon implement environmental dimensions of CSR as a safe buffer and a social dimension as philanthropy. Hence, there is no concrete evidence that industries promote sustainable development via CSR in Cameroon. The implementation of a sustainable business model is a precondition for promoting sustainable development via CSR. Industries should realize the concrete value in implementing a sustainable business model that helps to adjust to the complex and increasingly changing business environment.
Measurement and Study of Lidar Ratio by Using a Raman Lidar in Central China
Authors: Wang Wei , Gong Wei , Mao Feiyue , Pan Zengxin , Liu Boming
Published: May 2016

We comprehensively evaluated particle lidar ratios (i.e., particle extinction to backscatter ratio) at 532 nm over Wuhan in Central China by using a Raman lidar from July 2013 to May 2015. We utilized the Raman lidar data to obtain homogeneous aerosol lidar ratios near the surface through the Raman method during no-rain nights. The lidar ratios were approximately 57 ± 7 sr, 50 ± 5 sr, and 22 ± 4 sr under the three cases with obviously different pollution levels. The haze layer below 1.8 km has a large particle extinction coefficient (from 5.4e-4 m−1 to 1.6e-4 m−1) and particle backscatter coefficient (between 1.1e-05 m−1sr−1 and 1.7e-06 m−1sr−1) in the heavily polluted case. Furthermore, the particle lidar ratios varied according to season, especially between winter (57 ± 13 sr) and summer (33 ± 10 sr). The seasonal variation in lidar ratios at Wuhan suggests that the East Asian monsoon significantly affects the primary aerosol types and aerosol optical properties in this region. The relationships between particle lidar ratios and wind indicate that large lidar ratio values correspond well with weak winds and strong northerly winds, whereas significantly low lidar ratio values are associated with prevailing southwesterly and southerly wind.
MicroRNA-19b Downregulates Gap Junction Protein Alpha1 and Synergizes with MicroRNA-1 in Viral Myocarditis
Authors: Lin Junyi , Xue Aimin , Li Liliang , Li Beixu , Li Yuhua , Shen Yiwen , Sun Ning , Chen Ruizhen , Xu Hongfei , Zhao Ziqin
Published: May 2016

Viral myocarditis (VMC) is a life-threatening disease that leads to heart failure or cardiac arrhythmia. A large number of researches have revealed that mircroRNAs (miRNAs) participate in the pathological processes of VMC. We previously reported that miR-1 repressed the expression of gap junction protein α1 (GJA1) in VMC. In this study, miR-19b was found to be significantly upregulated using the microarray analysis in a mouse model of VMC, and overexpression of miR-19b led to irregular beating pattern in human cardiomyocytes derived from the induced pluripotent stem cells (hiPSCs-CMs). The upregulation of miR-19b was associated with decreased GJA1 in vivo. Furthermore, a miR-19b inhibitor increased, while its mimics suppressed the expression of GJA1 in HL-1 cells. When GJA1 was overexpressed, the miR-19b mimics-mediated irregular beating was reversed in hiPSCs-CMs. In addition, the effect of miR-19b on GJA1 was enhanced by miR-1 in a dose-dependent manner. These data suggest miR-19b contributes to irregular beating through regulation of GJA1 by cooperating with miR-1. Based on the present and our previous studies, it could be indicated that miR-19b and miR-1 might be critically involved in cardiac arrhythmia associated with VMC.
Novel Omega-3 Fatty Acid Epoxygenase Metabolite Reduces Kidney Fibrosis
Authors: Sharma Amit , Khan Md. , Levick Scott , Lee Kin , Hammock Bruce , Imig John
Published: May 2016

Cytochrome P450 (CYP) monooxygenases epoxidize the omega-3 polyunsaturated fatty acid (PUFA) docosahexaenoic acid into novel epoxydocosapentaenoic acids (EDPs) that have multiple biological actions. The present study determined the ability of the most abundant EDP regioisomer, 19,20-EDP to reduce kidney injury in an experimental unilateral ureteral obstruction (UUO) renal fibrosis mouse model. Mice with UUO developed kidney tubular injury and interstitial fibrosis. UUO mice had elevated kidney hydroxyproline content and five-times greater collagen positive fibrotic area than sham control mice. 19,20-EDP treatment to UUO mice for 10 days reduced renal fibrosis with a 40%–50% reduction in collagen positive area and hydroxyproline content. There was a six-fold increase in kidney α-smooth muscle actin (α-SMA) positive area in UUO mice compared to sham control mice, and 19,20-EDP treatment to UUO mice decreased α-SMA immunopositive area by 60%. UUO mice demonstrated renal epithelial-to-mesenchymal transition (EMT) with reduced expression of the epithelial marker E-cadherin and elevated expression of multiple mesenchymal markers (FSP-1, α-SMA, and desmin). Interestingly, 19,20-EDP treatment reduced renal EMT in UUO by decreasing mesenchymal and increasing epithelial marker expression. Overall, we demonstrate that a novel omega-3 fatty acid metabolite 19,20-EDP, prevents UUO-induced renal fibrosis in mice by reducing renal EMT.
Differential MicroRNA Expression Profile in Myxomatous Mitral Valve Prolapse and Fibroelastic Deficiency Valves
Authors: Chen Yei-Tsung , Wang Juan , Wee Abby , Yong Quek-Wei , Tay Edgar , Woo Chin , Sorokin Vitaly , Richards Arthur , Ling Lieng-Hsi
Published: May 2016

Myxomatous mitral valve prolapse (MMVP) and fibroelastic deficiency (FED) are two common variants of degenerative mitral valve disease (DMVD), which is a leading cause of mitral regurgitation worldwide. While pathohistological studies have revealed differences in extracellular matrix content in MMVP and FED, the molecular mechanisms underlying these two disease entities remain to be elucidated. By using surgically removed valvular specimens from MMVP and FED patients that were categorized on the basis of echocardiographic, clinical and operative findings, a cluster of microRNAs that expressed differentially were identified. The expressions of has-miR-500, -3174, -17, -1193, -646, -1273e, -4298, -203, -505, and -939 showed significant differences between MMVP and FED after applying Bonferroni correction (p < 0.002174). The possible involvement of microRNAs in the pathogenesis of DMVD were further suggested by the presences of in silico predicted target sites on a number of genes reported to be involved in extracellular matrix homeostasis and marker genes for cellular composition of mitral valves, including decorin (DCN), aggrecan (ACAN), fibromodulin (FMOD), α actin 2 (ACTA2), extracellular matrix protein 2 (ECM2), desmin (DES), endothelial cell specific molecule 1 (ESM1), and platelet/ endothelial cell adhesion molecule 1 (PECAM1), as well as inverse correlations of selected microRNA and mRNA expression in MMVP and FED groups. Our results provide evidence that distinct molecular mechanisms underlie MMVP and FED. Moreover, the microRNAs identified may be targets for the future development of diagnostic biomarkers and therapeutics.
A Comparative Analysis of Genetic and Epigenetic Events of Breast and Ovarian Cancer Related to Tumorigenesis
Authors: Longacre Mckenna , Snyder Nicole , Housman Genevieve , Leary Meghan , Lapinska Karolina , Heerboth Sarah , Willbanks Amber , Sarkar Sibaji
Published: May 2016

Breast cancer persists as the most common cause of cancer death in women worldwide. Ovarian cancer is also a significant source of morbidity and mortality, as the fifth leading cause of cancer death among women. This reflects the continued need for further understanding and innovation in cancer treatment. Though breast and ovarian cancer usually present as distinct clinical entities, the recent explosion of large-scale -omics research has uncovered many overlaps, particularly with respect to genetic and epigenetic alterations. We compared genetic, microenvironmental, stromal, and epigenetic changes common between breast and ovarian cancer cells, as well as the clinical relevance of these changes. Some of the most striking commonalities include genetic alterations of BRCA1 and 2, TP53, RB1, NF1, FAT3, MYC, PTEN, and PIK3CA; down regulation of miRNAs 9, 100, 125a, 125b, and 214; and epigenetic alterations such as H3K27me3, H3K9me2, H3K9me3, H4K20me3, and H3K4me. These parallels suggest shared features of pathogenesis. Furthermore, preliminary evidence suggests a shared epigenetic mechanism of oncogenesis. These similarities, warrant further investigation in order to ultimately inform development of more effective chemotherapeutics, as well as strategies to circumvent drug resistance.
MRI Reporter Genes for Noninvasive Molecular Imaging
Authors: Yang Caixia , Tian Rui , Liu Ting , Liu Gang
Published: May 2016

Magnetic resonance imaging (MRI) is one of the most important imaging technologies used in clinical diagnosis. Reporter genes for MRI can be applied to accurately track the delivery of cell in cell therapy, evaluate the therapy effect of gene delivery, and monitor tissue/cell-specific microenvironments. Commonly used reporter genes for MRI usually include genes encoding the enzyme (e.g., tyrosinase and β-galactosidase), the receptor on the cells (e.g., transferrin receptor), and endogenous reporter genes (e.g., ferritin reporter gene). However, low sensitivity limits the application of MRI and reporter gene-based multimodal imaging strategies are common including optical imaging and radionuclide imaging. These can significantly improve diagnostic efficiency and accelerate the development of new therapies.
Simultaneous Qualitative and Quantitative Analysis of Multiple Chemical Constituents in YiQiFuMai Injection by Ultra-Fast Liquid Chromatography Coupled with Ion Trap Time-of-Flight Mass Spectrometry
Authors: Liu Chunhua , Ju Aichun , Zhou Dazheng , Li Dekun , Kou Junping , Yu Boyang , Qi Jin
Published: May 2016

YiQiFuMai injection (YQFM) is a modern lyophilized powder preparation derived from the traditional Chinese medicine Sheng-mai san (SMS) used for treating cardiovascular diseases, such as chronic heart failure. However, its chemical composition has not been fully elucidated, particularly for the preparation derived from Ophiopogon japonicus. This study aimed to establish a systematic and reliable method to quickly and simultaneously analyze the chemical constituents in YQFM by ultra-fast liquid chromatography coupled with ion trap time-of-flight mass spectrometry (UFLC-IT-TOF/MS). Sixty-five compounds in YQFM were tentatively identified by comparison with reference substances or literature data. Furthermore, twenty-one compounds, including three ophiopogonins, fifteen ginsenosides and three lignans were quantified by UFLC-IT-TOF/MS. Notably, this is the first determination of steroidal saponins from O. japonicus in YQFM. The relative standard deviations (RSDs) of intra- and inter-day precision, reproducibility and stability were <4.9% and all analytes showed good linearity (R2 ≥ 0.9952) and acceptable recovery of 91.8%–104.2% (RSD ≤ 5.4%), indicating that the methods were reliable. These methods were successfully applied to quantitative analysis of ten batches of YQFM. The developed approach can provide useful and comprehensive information for quality control, further mechanistic studies in vivo and clinical application of YQFM.
Synthesis and Antioxidant Activity of Alkyl Nitroderivatives of Hydroxytyrosol
Authors: Gallardo Elena , Palma-Valdés Rocío , Sarriá Beatriz , Gallardo Irene , De la Cruz José , Bravo Laura , Mateos Raquel , Espartero José
Published: May 2016

A series of alkyl nitrohydroxytyrosyl ether derivatives has been synthesized from free hydroxytyrosol (HT), the natural olive oil phenol, in order to increase the assortment of compounds with potential neuroprotective activity in Parkinson’s disease. In this work, the antioxidant activity of these novel compounds has been evaluated using Ferric Reducing Antioxidant Power (FRAP), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and Oxygen Radical Scavenging Capacity (ORAC) assays compared to that of nitrohydroxytyrosol (NO2HT) and free HT. New compounds showed variable antioxidant activity depending on the alkyl side chain length; compounds with short chains (2–4 carbon atoms) maintained or even improved the antioxidant activity compared to NO2HT and/or HT, whereas those with longer side chains (6–8 carbon atoms) showed lower activity than NO2HT but higher than HT.
Asiatic Acid Prevents the Deleterious Effects of Valproic Acid on Cognition and Hippocampal Cell Proliferation and Survival
Authors: Umka Welbat Jariya , Sirichoat Apiwat , Chaijaroonkhanarak Wunnee , Prachaney Parichat , Pannangrong Wanassanun , Pakdeechote Poungrat , Sripanidkulchai Bungorn , Wigmore Peter
Published: May 2016

Valproic acid (VPA) is commonly prescribed as an anticonvulsant and mood stabilizer used in the treatment of epilepsy and bipolar disorder. A recent study has demonstrated that VPA reduces histone deacetylase (HDAC) activity, an action which is believed to contribute to the effects of VPA on neural stem cell proliferation and differentiation which may explain the cognitive impairments produced in rodents and patients. Asiatic acid is a triterpenoid derived from the medicinal plant Centella asiatica. Our previous study has shown that Asiatic acid improves working spatial memory and increases cell proliferation in the sub granular zone of the hippocampal dentate gyrus. In the present study we investigate the effects of Asiatic acid in preventing the memory and cellular effects of VPA. Male Spraque-Dawley rats were orally administered Asiatic acid (30 mg/kg/day) for 28 days, while VPA-treated animals received injections of VPA (300 mg/kg) twice a day from Day 15 to Day 28 for 14 days. Spatial memory was determined using the novel object location (NOL) test and hippocampal cell proliferation and survival was quantified by immuostaining for Ki-67 and Bromodeoxyuridine (BrdU), respectively. The results showed that VPA-treated animals were unable to discriminate between objects in familiar and novel locations. Moreover, VPA significantly reduced numbers of Ki-67 and BrdU positive cells. These results indicate that VPA treatment caused impairments of spatial working memory, cell proliferation and survival in the subgranular zone (SGZ) of the hippocampal dentate gyrus (DG). However, these abnormalities were restored to control levels by co-treatment with Asiatic acid. These data demonstrate that Asiatic acid could prevent the spatial memory and neurogenesis impairments caused by VPA.
Measuring Micro-Friction Torque in MEMS Gas Bearings
Authors: Fang Xudong , Liu Huan
Published: May 2016

An in situ measurement of micro-friction torque in MEMS gas bearings, which has been a challenging research topic for years, is realized by a system designed in this paper. In the system, a high accuracy micro-force sensor and an electronically-driven table are designed, fabricated and utilized. With appropriate installation of the sensor and bearings on the table, the engine rotor can be driven to rotate with the sensor using a silicon lever beam. One end of the beam is fixed to the shaft of the gas bearing, while the other end is free and in contact with the sensor probe tip. When the sensor begins to rotate with the table, the beam is pushed by the sensor probe to rotate in the same direction. For the beam, the friction torque from the gas bearing is balanced by the torque induced by pushing force from the sensor probe. Thus, the friction torque can be calculated as a product of the pushing force measured by the sensor and the lever arm, which is defined as the distance from the sensor probe tip to the centerline of the bearing. Experimental results demonstrate the feasibility of this system, with a sensitivity of 1.285 mV/μN·m in a range of 0 to 11.76 μN·m when the lever arm is 20 mm long. The measuring range can be modified by varying the length of the lever arm. Thus, this system has wide potential applications in measuring the micro-friction torque of gas bearings in rotating MEMS machines.
A New Approach for the Characterization of Organic Residues from Stone Tools Using GC×GC-TOFMS
Authors: Perrault Katelynn , Stefanuto Pierre-Hugues , Dubois Lena , Cnuts Dries , Rots Veerle , Focant Jean-François
Published: May 2016

Headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) have traditionally been used, in combination with other analyses, for the chemical characterization of organic residues recovered from archaeological specimens. Recently in many life science fields, comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS) has provided numerous benefits over GC-MS. This study represents the first use of HS-SPME-GC×GC-TOFMS to characterize specimens from an experimental modern reference collection. Solvent extractions and direct analyses were performed on materials such as ivory, bone, antlers, animal tissue, human tissue, sediment, and resin. Thicker film column sets were preferred due to reduced column overloading. The samples analyzed by HS-SPME directly on a specimen appeared to give unique signatures and generally produced a higher response than for the solvent-extracted residues. A non-destructive screening approach of specimens may, therefore, be possible. Resin and beeswax mixtures prepared by heating for different lengths of time appeared to provide distinctly different volatile signatures, suggesting that GC×GC-TOFMS may be capable of differentiating alterations to resin in future studies. Further development of GC×GC-TOFMS methods for archaeological applications will provide a valuable tool to uncover significant information on prehistoric technological changes and cultural behavior.