2,614 research outputs found
Chemical constituents and bioactivity of Malaysian and Indonesian kaempferia rotunda
The essential oils and the phytochemicals of the rhizomes of Kaempferia rotunda cultivated in Malaysia and Indonesia have been studied. Hydrodistillation of the fresh rhizomes of K. rotunda gave 0.09% and 0.23% oils respectively. These oils were analyzed by GC (Kovats Indices) and GC-MS. The main constituents found in the rhizome oil of Malaysia were bornyl acetate (9.6%), benzyl benzoate (8.4%) and camphor (5.6%), while the rhizome oil from Indonesia was rich in benzyl benzoate (87.7%) and n-pentadecane (4.2%). Extractions by soxhlet apparatus were carried out on the dried samples to get the crude extracts. Fractionation and purification on the crude extracts resulted in the isolation of three new cyclohexane oxides and ten known compounds, comprising of cyclohexane oxides, esters, carboxylic acid, labdane diterpene, and flavonoids. Two new compounds identified as 2- (benzoyloxymethyl)phenyl (3-O-acetyl)-Ć-glucopyranoside and 3-debenzoylrotepoxide A, together with seven known compounds, crotepoxide, 4- benzoyloxymethyl-3,8-dioxatricyclo[5.1.0.02,4]octane-5,6-diol 5-acetate, 1,6- desoxypipoxide, curcumrinol C, 2'-hydroxy-4,4',6'-trimethoxychalcone and naringenin 4',7-dimethyl ether were isolated from the Malaysian species, while a new compound identified as 3-acetoxy-2-benzoyloxy-1-(benzoyloxymethyl)-cyclohexa- 4,6-diene with the seven known compounds namely crotepoxide, 4- benzoyloxymethyl-3,8-dioxatricyclo[5.1.0.02,4]octane-5,6-diol 5-acetate, 1,6- desoxypipoxide, 6-acetylzeylenol, trans-docosyl ferulate, benzyl benzoate and benzoic acid were isolated from the Indonesian species. The structures of all compounds were established based on spectral studies using MS, IR, UV and NMR spectroscopies. Naringenin 4',7-dimethyl ether, curcumrinol C, trans-docosyl ferulate, and benzoic acid were found for the first time from K. rotunda and also the genus of Kaempferia. Antibacterial and antioxidant screening assays using discdiffusion method and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) method, respectively were carried out on the crude extracts and essential oils. The crude extracts and essential oils of K. rotunda from Malaysia and Indonesia did not show activities on antibacterial and antioxidant assay
The neural basis of responsibility attribution in decision-making
Social responsibility links personal behavior with societal expectations and plays a key role in affecting an agent's emotional state following a decision. However, the neural basis of responsibility attribution remains unclear. In two previous event-related brain potential (ERP) studies we found that personal responsibility modulated outcome evaluation in gambling tasks. Here we conducted a functional magnetic resonance imaging (fMRI) study to identify particular brain regions that mediate responsibility attribution. In a context involving team cooperation, participants completed a task with their teammates and on each trial received feedback about team success and individual success sequentially. We found that brain activity differed between conditions involving team success vs. team failure. Further, different brain regions were associated with reinforcement of behavior by social praise vs. monetary reward. Specifically, right temporoparietal junction (RTPJ) was associated with social pride whereas dorsal striatum and dorsal anterior cingulate cortex (ACC) were related to reinforcement of behaviors leading to personal gain. The present study provides evidence that the RTPJ is an important region for determining whether self-generated behaviors are deserving of praise in a social context
Effects of central activation of serotonin 5-HT2A/2C or dopamine D-2/3 receptors on the acute and repeated effects of clozapine in the conditioned avoidance response test
Acute administration of clozapine (a gold standard of atypical antipsychotics) disrupts avoidance response in rodents, while repeated administration often causes a tolerance effect
Border is better than distance? Contagious corruption in one belt one road economies
Employing data of one belt one road (OBOR) countries from 2002 to 2013, this study compares the contagious corruption difference between geographic border and distance through the dynamic spatial econometric model. The empirical results not only confirm that corruption in OBOR countries exists under various contagious channels, but also indicate that border effects, serving as contagious channels for corruption, are better than distance effects. The empirical implication is that OBOR countries with a common border tend to possess contagious corruption due to the hostsā demonstration effect and the convenience of transferring illegal assets. We advise that those OBOR countries should enhance the supervision of cash flow, look for any opportunity of kicking back a portion of the stolen money, and establish a specific task force on corruption
Revocable, Interoperable and User-Centric (Active) Authentication Across Cyberspace
This work addresses fundamental and challenging user authentication and universal identity issues and solves the problems of system usability, authentication data security, user privacy, irrevocability, interoperability, cross-matching attacks, and post-login authentication breaches associated with existing authentication systems. It developed a solid user-centric biometrics based authentication model, called Bio-Capsule (BC), and implemented an (active) authentication system. BC is the template derived from the (secure) fusion of a userās biometrics and that of a Reference Subject (RS). RS is simply a physical object such as a doll or an artificial one, such as an image. It is usersā BCs, rather than original biometric templates, that are utilized for user authentication and identification. The implemented (active) authentication system will facilitate and safely protect individualsā diffused cyber activities, which is particularly important nowadays, when people are immersed in cyberspace.
User authentication is the first guard of any trustworthy computing system. Along with peopleās immersion in the penetrated cyber space integrated with information, networked systems, applications and mobility, universal identity security& management and active authentication become of paramount importance for cyber security and user privacy. Each of three typical existing authentication methods, what you KNOW (Password/PIN), HAVE (SmartCard), and ARE (Fingerprint/Face/Iris) and their combinations, suffer from their own inherent problems. For example, biometrics is becoming a promising authentication/identification method because it binds an individual with his identity, is resistant to losses, and does not need to memorize/carry. However, biometrics introduces its own challenges. One serious problem with biometrics is that biometric templates are hard to be replaced once compromised. In addition, biometrics may disclose userās sensitive information (such as race, gender, even health condition), thus creating user privacy concerns. In the recent years, there has been intensive research addressing biometric template security and replaceability, such as cancelable biometrics and Biometric Cryptosystems. Unfortunately, these approaches do not fully exploit biometric advantages (e.g., requiring a PIN), reduce authentication accuracy, and/or suffer from possible attacks. The proposed approach is the first elegant solution to effectively address irreplaceability, privacy-preserving, and interoperability of both login and after-login authentication. Our methodology preserves biometricsā robustness and accuracy, without sacrificing system acceptability for the same user, and distinguishability between different users. Biometric features cannot be recovered from the userās Biometric Capsule or Reference Subject, even when both are stolen. The proposed model can be applied at the signal, feature, or template levels, and facilitates integration with new biometric identification methods to further enhance authentication performance. Moreover, the proposed active, non-intrusive authentication is not only scalable, but also particularly suitable to emerging portable, mobile computing devices. In summary, the proposed approach is (i) usercentric, i.e., highly user friendly without additional burden on users, (ii) provably secure and resistant to attacks including cross-matching attacks, (iii) identity-bearing and privacy-preserving, (iv) replaceable, once Biometric Capsule is compromised, (v) scalable and highly adaptable, (vi) interoperable and single signing on across systems, and (vii) cost-effective and easy to use
Genetic linkage maps of Pinus koraiensis Sieb. et Zucc. based on AFLP markers
Genetic linkage maps provide essential information for molecular breeding. In this paper, the genetic linkage map of Pinus koraiensis was constructed using an F1 progeny of 88 individuals. One hundred and thirty (130) of molecular markers were mapped onto 6 linkage groups, 4 triples and 15 pairs at the linkage criteria LOD 4.0. Nine primer combinations were applied to map construction. The consensus map gained covers 620.909 cM, with an average marker spacing of 4.776 cM. The presented map provides crucial information for future genomic studies of P. koraiensis, in particular for QTL (quantitative trait loci) mapping of economically important breeding target traits.Keywords: Genetic mapping, Korean pine, linkage map, marker-aided selectionAfrican Journal of Biotechnology Vol. 9(35), pp. 5659-5664, 30 August, 201
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