Small volume laboratory on a chip measurements incorporating the quartz crystal microbalance to measure the viscosity-density product of room temperature ionic liquids

A microfluidic glass chip system incorporating a quartz crystal microbalance (QCM) to measure the square root of the viscosity-density product of room temperature ionic liquids (RTILs) is presented. The QCM covers a central recess on a glass chip, with a seal formed by tightly clamping from above outside the sensing region. The change in resonant frequency of the QCM allows for the determination of the square root viscosity-density product of RTILs to a limit of ∼ 10 kg m−2 s−0.5. This method has reduced the sample size needed for characterization from 1.5 ml to only 30 μl and allows the measurement to be made in an enclosed system

Attributes Enhanced Role-Based Access Control Model

Abstract. Attribute-based access control (ABAC) and role-based access control (RBAC) are currently the two most popular access con-trol models. Yet, they both have known limitations and offer features complimentary to each other. Due to this fact, integration of RBAC and ABAC has recently emerged as an important area of research. In this paper, we propose an access control model that combines the two mod-els in a novel way in order to unify their benefits. Our approach provides a fine-grained access control mechanism that not only takes contextual information into account while making the access control decisions but is also suitable for applications where access to resources is controlled by exploiting contents of the resources in the policy

Robust Binding of Disulfide-Substituted Rhenium Bipyridyl Complexes for CO2 Reduction on Gold Electrodes

Heterogenization of homogenous catalysts on electrode surfaces provides a valuable approach for characterization of catalytic processes in operando conditions using surface selective spectroelectrochemistry methods. Ligand design plays a central role in the attachment mode and the resulting functionality of the heterogenized catalyst as determined by the orientation of the catalyst relative to the surface and the nature of specific interactions that modulate the redox properties under the heterogeneous electrode conditions. Here, we introduce new [Re(L)(CO)3Cl] catalysts for CO2 reduction with sulfur-based anchoring groups on a bipyridyl ligand, where L = 3,3′-disulfide-2,2′-bipyridine (SSbpy) and 3,3′-thio-2,2′-bipyridine (Sbpy). Spectroscopic and electrochemical analysis complemented by computational modeling at the density functional theory level identify the complex [Re(SSbpy)(CO)3Cl] as a multi-electron acceptor that combines the redox properties of both the rhenium tricarbonyl core and the disulfide functional group on the bipyridyl ligand. The first reduction at −0.85 V (vs. SCE) involves a two-electron process that breaks the disulfide bond, activating it for surface attachment. The heterogenized complex exhibits robust anchoring on gold surfaces, as probed by vibrational sum-frequency generation (SFG) spectroscopy. The binding configuration is normal to the surface, exposing the active site to the CO2 substrate in solution. The attachment mode is thus particularly suitable for electrocatalytic CO2 reduction.Fil: Cattaneo, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Guo, Facheng. University of Yale; Estados UnidosFil: Kelly, H. Ray. University of Yale; Estados UnidosFil: Videla, Pablo E.. University of Yale; Estados UnidosFil: Kiefer, Laura. Emory University; Estados UnidosFil: Gebre, Sara. Emory University; Estados UnidosFil: Ge, Aimin. Emory University; Estados UnidosFil: Liu, Qiliang. Emory University; Estados UnidosFil: Wu, Shaoxiong. Emory University; Estados UnidosFil: Lian, Tianquan. Emory University; Estados UnidosFil: Batista, Víctor S.. University of Yale; Estados Unido

Sirt6 regulates TNFα secretion via hydrolysis of long chain fatty acyl lysine

The Sir2 family of enzymes or sirtuins are known as nicotinamide adenine dinucleotide (NAD)-dependent deacetylases1 and have been implicated in the regulation of transcription, genome stability, metabolism, and lifespan2, 3. However, four of the seven mammalian sirtuins have very weak deacetylase activity in vitro. Here we show that human Sirt6 efficiently removes long chain fatty acyl groups, such as myristoyl, from lysine residues. The crystal structure of Sirt6 reveals a large hydrophobic pocket that can accommodate long chain fatty acyl groups. We demonstrate further that Sirt6 promotes the secretion of tumor necrosis factor α (TNFα) by removing the fatty acyl modification on K19 and K20 of TNFα. Protein lysine fatty acylation has been known to occur in mammalian cells, but the function and regulatory mechanisms of this modification were unknown. Our data suggest that protein lysine fatty acylation is a novel mechanism that regulates protein secretion. The discovery of Sirt6 as an enzyme that controls protein lysine fatty acylation provides new opportunities to investigate the physiological function of the previously ignored protein posttranslational modification

Original Article Triptolide induces anti-inflammatory cellular responses

Abstract: Tripterygium wilfordii Hook F. has been used for centuries in traditional Chinese medicine to treat rheumatoid arthritis, an autoimmune disease associated with increased production of the pro-inflammatory cytokine, tumor necrosis factor (TNF)-α. Triptolide is a compound originally purified from T. wilfordii Hook F. and has potent anti-inflammatory and immunosuppressant activities. In this study, we investigated the effect of triptolide on the global gene expression patterns of macrophages treated with lipopolysaccharide (LPS). We found that LPS stimulation resulted in >5-fold increase in expression of 117 genes, and triptolide caused a >50% inhibition in 47 of the LPS-inducible 117 genes. A large portion of the genes that were strongly induced by LPS and significantly inhibited by triptolide were pro-inflammatory cytokine and chemokine genes, including TNF-α, IL-1β, and IL-6. Interestingly, LPS also induced the expression of micro-RNA-155 (miR-155) precursor, BIC, which was inhibited by triptolide. Confirming the cDNA array results, we demonstrated that triptolide blocked the induction of these pro-inflammatory cytokines as well as miR-155 in a dose-dependent manner. Profound inhibition of pro-inflammatory cytokine expression was observed at concentrations as low as 10-50 nM. However, triptolide neither inhibited the phosphorylation or degradation of IBα after LPS stimulation, nor affected the DNAbinding activity of NF-B. Surprisingly, we found that triptolide not only inhibited NF-B-regulated reporter transcription, but also dramatically blocked the activity of other transcription factors. Our study offers a plausible explanation of the therapeutic mechanism of T. wilfordii Hook F

Positive predictive value of automated database records for diabetic ketoacidosis (DKA) in children and youth exposed to antipsychotic drugs or control medications: a tennessee medicaid study

<p>Abstract</p> <p>Background</p> <p>Diabetic ketoacidosis (DKA) is a potentially life-threatening complication of treatment with some atypical antipsychotic drugs in children and <b>youth</b>. Because drug-associated DKA is rare, large automated health outcomes databases may be a valuable data source for conducting pharmacoepidemiologic studies of DKA associated with exposure to individual antipsychotic drugs. However, no validated computer case definition of DKA exists. We sought to assess the positive predictive value (PPV) of a computer case definition to detect incident cases of DKA, using automated records of Tennessee Medicaid as the data source and medical record confirmation as a "gold standard."</p> <p>Methods</p> <p>The computer case definition of DKA was developed from a retrospective cohort study of antipsychotic-related type 2 diabetes mellitus (1996-2007) in Tennessee Medicaid enrollees, aged 6-24 years. Thirty potential cases with any DKA diagnosis (ICD-9 250.1, ICD-10 E1x.1) were identified from inpatient encounter claims. Medical records were reviewed to determine if they met the clinical definition of DKA.</p> <p>Results</p> <p>Of 30 potential cases, 27 (90%) were successfully abstracted and adjudicated. Of these, 24 cases were confirmed by medical record review (PPV 88.9%, 95% CI 71.9 to 96.1%). Three non-confirmed cases presented acutely with severe hyperglycemia, but had no evidence of acidosis.</p> <p>Conclusions</p> <p>Diabetic ketoacidosis in children and youth can be identified in a computerized Medicaid database using our case definition, which could be useful for automated database studies in which drug-associated DKA is the outcome of interest.</p