Concerning bounded-right-context grammars

Consider the problem of testing whether a context-free grammar is an (m, n)-BRC grammar. Let 6G6 denote the size of the grammar G. It is first shown that G is (m, n)-BRC if and only if G is (m₀, n)-BRC where m₀=4·6G6²·(n + 1)². Deterministic and nondeterministic algorithms are then presented for testing whether an arbitrary grammar has the (m, n)-BRC property for fixed values of m and n. The running times of both algorithms are low degree polynomials which are independent of m.     

Affinity-capture tandem mass spectrometric characterization of polyprenyl-linked oligosaccharides: tool to study protein N-glycosylation pathways

N-glycosylation of proteins is recognized as one of the most common post-translational modifications. Until recently it was believed that N-glycosylation occurred exclusively in eukaryotes before the discovery of the general protein glycosylation pathway (Pgl) in Campylobacter jejuni. To date, most techniques to analyze lipid-linked oligosaccharides (LLOs) of these pathways involve the use of radiolabels and chromatographic separation. Technologies capable of characterizing eukaryotic and the newly described bacterial N-glycosylation systems from biologically relevant samples in a quick, accurate, and cost-effective manner are needed. In this paper a new glycomics strategy based on lectin-affinity capture was devised and validated on the C. jejuni N-glycan pathway and the engineered Escherichia coli strains expressing the functional C. jejuni pathway. The lipid-linked oligosaccharide intermediates of the Pgl pathway were then enriched using SBA-agarose affinity-capture and examined by capillary electrophoresis-mass spectrometry (CE-MS). We demonstrate that this method is capable of detecting low levels of LLOs, the sugars are indeed assembled on undecaprenylpyrophosphate, and structural information for expected and unexpected LLOs can be obtained without further sample manipulation. Furthermore, CE-MS analyses of C. jejuni and the E. coli "glyco-factories" showed striking differences in the assembly and control of N-glycan biosynthesis.     

Secure Multi-copy Routing in Compromised Delay Tolerant Networks

Routing in delay tolerant networks (DTNs) is challenging due to their unique characteristics of intermittent node connectivity. Different protocols (single-, multi-copy, erasure-coding-based etc.) utilizing store-carry-and-forward paradigm have been proposed to achieve routing of messages in such environments by opportunistic message exchanges between nodes that are in the communication range of each other. The sparsity and distributed nature of these networks together with the lack of stable connectivity between source destination pairs make these networks vulnerable to malicious nodes which might attempt to learn the content of the messages being routed between the nodes. In this paper, we study DTNs in which malicious nodes are present, to which we refer to as compromised DTNs. We discuss and analyze the effects of presence of malicious nodes on routing of messages in compromised DTNs. We propose a two period routing approach which aims at achieving the desired delivery ratio by a given delivery deadline in presence of malicious nodes. Our simulation results with both random networks and real DTN traces show that, with proper parameter setting, the proposed method can achieve delivery ratios which surpass those reached by other algorithms by a given delivery deadline.     

Resource provisioning for multigranular traffic flows in multilayer networks

The paper deals with the problem of multilayer resource provisioning in a network in which an operator needs to route traffic flows with different data rates. It is shown that the blocking probability of high data rate requests is usually higher than the blocking probability of other requests. A relevant strategy aimed at solving this problem is proposed, investigated, and compared with the known solution. Numerical results confirm that the proposed strategy is able to substantially reduce the blocking probability of high data rate requests at the cost of increased utilization of the packet switching layer and more complex routing of lightpaths.     

Penetration of Monodisperse,Singly Charged Nanoparticles through Polydisperse Fibrous Filters

The article presents experimental results and theoretical analysis of aerosol nanoparticle penetration through fibrous filters with a broad fiber diameter distribution. Four fibrous filters were produced using the melt-blown technique. The analysis of the filters’ SEM images indicated that they had log-normal fiber diameter distribution. Five kinds of proteins and two types of silica particles were generated by electrospraying and were then classified using a Parallel Differential Mobility Analyzer to obtain well-defined, monodisperse, singly charged challenge aerosols with diameters ranging from 6.3 to 27.2 nm. Particle penetration through the filters was determined using a water-based CPC. Experimental results were compared first with predictions derived from the classical theory of aerosol filtration. It is demonstrated that it is inappropriate to apply it to the arithmetic mean fiber diameter, as this results in turn in a huge underestimation of nanoparticle penetration. A better, but still unsatisfactory agreement is observed when that theory was used together with the pressure drop equivalent fiber diameter or when the Kirsch model of nonuniform fibrous media was applied. We show that the classical theory applied to any fixed fiber diameter predicts a stronger dependence of nanoparticle penetration on the Peclet number as compared to experimental data. All these observations were successfully explained by using our original partially segregated flow model that accounts for the filter fiber diameter distribution. It was found that the parameter of aerosol segregation intensity inside inhomogeneous filters increases with the increase in particle size, when the convective transport becomes more pronounced in comparison to the diffusive one.     

"Examining the relationship between multiple internalized oppressions and African American lesbian, gay, bisexual, and questioning persons’ self-esteem and psychological distress”: Correction.

Reports an error in "Examining the relationship between multiple internalized oppressions and African American lesbian, gay, bisexual, and questioning persons' self-esteem and psychological distress" by Dawn M. Szymanski and Arpana Gupta (Journal of Counseling Psychology, 2009[Jan], Vol 56[1], 110-118). The DOI was incorrect. The correct DOI is 10.1037/a0013317. (The following abstract of the original article appeared in record 2009-00624-002.) Lesbian, gay, bisexual, and questioning (LGBQ) persons come from diverse cultural groups with diverse racial and ethnic identities. However, most research on LGBQ persons has used primarily White samples, and most research on African Americans has used largely heterosexual samples. Thus, research has largely failed to attend to and investigate the complexity of African American LGBQ persons' experiences. This study examined the relations between multiple internalized oppressions and African American sexual minority persons' self-esteem and psychological distress. Results indicated that when examined together, internalized racism and internalized heterosexism (also known as internalized homophobia) were both significant negative predictors of self-esteem, but only internalized heterosexism was a unique positive predictor of psychological distress. The interaction of internalized racism and internalized heterosexism was not a significant predictor of self-esteem or psychological distress. Finally, the authors' findings indicate that self-esteem partially mediates the relationship between internalized heterosexism and psychological distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examining potential moderators of the link between heterosexist events and gay and bisexual men's psychological distress.

The purpose of this study was to examine (a) the relationship between heterosexist events and psychological distress and (b) the potential moderating roles of social support, avoidant coping, and self-esteem in the relationship between heterosexist events and psychological distress among 210 gay and bisexual men. Findings from the Web-based Internet survey revealed that many gay and bisexual men experienced heterosexist harassment, rejection, and discrimination at least once in a while during the past year and that these experiences were positively related to psychological distress. Results also indicated that self-esteem moderated the relationship between heterosexist events and psychological distress, with significant risk being associated with low self-esteem. No support was found for the moderating roles of social support and avoidant coping in the link between heterosexist events and psychological distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Primary structure of 2S albumin from seeds of Lupinus cosentinii

 The 2S albumin from seeds of Lupinus cosentinii Guss. was purified, and the complete amino acid sequences of the dominating small and large subunit were determined by automated Edman degradation of the reduced and S-pyridylethylated polypeptides and of their enzymatic fragments. The small subunit of the 2S albumin consists of 35 amino acid residues resulting in a molecular mass (M _r) of 4233. The large subunit contains 73 amino acid residues (M _r = 8627). The two polypeptide chains are linked by two interchain disulphide bonds. In addition, the large polypeptide contains two intrachain disulphide bridges and one free sulphydryl group. A high degree of homology (88–89%) exists between the primary structure of the 2S albumin from L. cosentinii and those from other Lupinus species. The positions of the cysteines and of some other amino acids are conserved not only in most of the Dicotyledoneae 2S albumins sequenced so far but also in other storage proteins. Received: 26 May 1997     

Light-Control over Casein Kinase 1δ Activity with Photopharmacology: A Clear Case for Arylazopyrazole-Based Inhibitors

Protein kinases are responsible for healthy cellular processes and signalling pathways, and their dysfunction is the basis of many pathologies. There are numerous small molecule inhibitors of protein kinases that systemically regulate dysfunctional signalling processes. However, attaining selectivity in kinase inhibition within the complex human kinome is still a challenge that inspires unconventional approaches. One of those approaches is photopharmacology, which uses light-controlled bioactive molecules to selectively activate drugs only at the intended space and time, thereby avoiding side effects outside of the irradiated area. Still, in the context of kinase inhibition, photopharmacology has thus far been rather unsuccessful in providing light-controlled drugs. Here, we present the discovery and optimisation of a photoswitchable inhibitor of casein kinase 1δ (CK1δ), important for the control of cell differentiation, circadian rhythm, DNA repair, apoptosis, and numerous other signalling processes. Varying the position at which the light-responsive azobenzene moiety has been introduced into a known CK1δ inhibitor, LH846, revealed the preferred regioisomer for efficient photo-modulation of inhibitory activity, but the photoswitchable inhibitor suffered from sub-optimal (photo)chemical properties. Replacement of the bis-phenyl azobenzene group with the arylazopyrazole moiety yielded a superior photoswitch with very high photostationary state distributions, increased solubility and a 10-fold difference in activity between irradiated and thermally adapted samples. The reasons behind those findings are explored with molecular docking and molecular dynamics simulations. Results described here show how the evaluation of privileged molecular architecture, followed by the optimisation of the photoswitchable unit, is a valuable strategy for the challenging design of the photoswitchable kinase inhibitors.     

Clinical application of region-of-interest techniques to radiologic imaging

In region-of-interest (ROI) imaging, a filter with a central aperture is used to substantially reduce patient dose outside of an ROI while maintaining or improving image quality within the ROI. The benefits of ROI imaging can be realized by using standard imaging equipment. ROI imaging has been clinically applied to gastrointestinal radiology and interventional procedures. In gastrointestinal procedures, ROI fluoroscopy without image processing can be used without adversely affecting the procedure or interfering with spot radiography. ROI fluoroscopy can reduce the dose-area product by a factor of 1.7 for gastrointestinal procedures. In interventional neuroradiologic procedures, equalized display brightness is achieved with road mapping during fluoroscopy and with standard digital subtraction techniques during angiography. In interventional radiology, ROI filters can generally reduce the patient skin dose to levels below the threshold for skin effects, thus eliminating these effects across more than 85% of the field of view.