Kinetic and thermodynamics study of the pyrolytic process of the freshwater macroalga,Chara vulgaris

This is the first study where the pyrolysis of the freshwater macroalga Chara vulgaris was explored to reveal its bioenergy potential. The suitability of C. vulgaris to bioenergy conversion via pyrolysis was accessed in terms of kinetic triplet and thermodynamic parameters. For this purpose, pyrolysis experiments under a thermogravimetric scale were conducted at multiple heating rates (5, 10, and 20 °C min^?1) in an inert atmosphere. The mass-loss profiles of C. vulgaris pyrolysis showed that there are two dominant decomposition stages that are related to distinct chemical components inside its structure and that directly affect the calculated kinetic triplet and thermodynamics parameters. The average activation energy obtained using isoconversional methods of Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, Starink, and Friedman was in the range of 52.87–72.91 kJ mol^?1 for the first decomposition stage and 156.14–174.65 kJ mol^?1 for the second decomposition stage. The pyrolytic conversion of C. vulgaris initially follows a second-order reaction model (first decomposition stage), while in second decomposition stage is controlled by a second-order Avrami-Erofeev reaction model. The kinetic results derived from the non-isothermal decomposition of C. vulgaris proved its suitable characteristics for pyrolysis. Additionally, multi-stage kinetic interpretation was successfully attained based on two kinetic triplets, where reconstructed pyrolysis behavior correlated well with experimental pyrolysis behavior. The changes in enthalpy, Gibbs free energy, and entropy for first decomposition stage were 67.58±0.25 kJ mol^?1, 180.77±5.30 kJ mol^?1, and ?176.65±0.41 J mol^?1 K^?1, and for the second decomposition stage the values were 166.70±0.09 kJ mol^?1, 285.51±1.29 kJ mol^?1, and ?124.29±0.09 J mol^?1 K^?1, respectively. Based on thermodynamic aspects, C. vulgaris is particularly interesting for use as a raw material to produce biofuels and bioenergy.

     

Ribosome Biogenesis in African Trypanosomes Requires Conserved and Trypanosome-Specific Factors

Large ribosomal subunit protein L5 is responsible for the stability and trafficking of 5S rRNA to the site of eukaryotic ribosomal assembly. In Trypanosoma brucei, in addition to L5, trypanosome-specific proteins P34 and P37 also participate in this process. These two essential proteins form a novel preribosomal particle through interactions with both the ribosomal protein L5 and 5S rRNA. We have generated a procyclic L5 RNA interference cell line and found that L5 itself is a protein essential for trypanosome growth, despite the presence of other 5S rRNA binding proteins. Loss of L5 decreases the levels of all large-subunit rRNAs, 25/28S, 5.8S, and 5S rRNAs, but does not alter small-subunit 18S rRNA. Depletion of L5 specifically reduced the levels of the other large ribosomal proteins, L3 and L11, whereas the steady-state levels of the mRNA for these proteins were increased. L5-knockdown cells showed an increase in the 40S ribosomal subunit and a loss of the 60S ribosomal subunits, 80S monosomes, and polysomes. In addition, L5 was involved in the processing and maturation of precursor rRNAs. Analysis of polysomal fractions revealed that unprocessed rRNA intermediates accumulate in the ribosome when L5 is depleted. Although we previously found that the loss of P34 and P37 does not result in a change in the levels of L5, the loss of L5 resulted in an increase of P34 and P37 proteins, suggesting the presence of a compensatory feedback loop. This study demonstrates that ribosomal protein L5 has conserved functions, in addition to nonconserved trypanosome-specific features, which could be targeted for drug intervention.     

Synthetic pre-microRNAs reveal dual-strand activity of miR-34a on TNF-α

Functional microRNAs (miRNAs) are produced from both arms of their precursors (pre-miRNAs). Their abundances vary in context-dependent fashion spatiotemporarily and there is mounting evidence of regulatory interplay between them. Here, we introduce chemically synthesized pre-miRNAs (syn-pre-miRNAs) as a general class of accessible, easily transfectable mimics of pre-miRNAs. These are RNA hairpins, identical in sequence to natural pre-miRNAs. They differ from commercially available miRNA mimics through their complete hairpin structure, including any regulatory elements in their terminal-loop regions and their potential to introduce both strands into RISC. They are distinguished from transcribed pre-miRNAs by their terminal 5′ hydroxyl groups and their precisely defined terminal nucleotides. We demonstrate with several examples how they fully recapitulate the properties of pre-miRNAs, including their processing by Dicer into functionally active 5p; and 3p-derived mature miRNAs. We use syn-pre-miRNAs to show that miR-34a uses its 5p and 3p miRNAs in two pathways: apoptosis during TGF-β signaling, where SIRT1 and SP4 are suppressed by miR-34a-5p and miR-34a-3p, respectively; and the lipopolysaccharide (LPS)-activation of primary human monocyte-derived macrophages, where TNF (TNFα) is suppressed by miR-34a-5p indirectly and miR-34a-3p directly. Our results add to growing evidence that the use of both arms of a miRNA may be a widely used mechanism. We further suggest that syn-pre-miRNAs are ideal and affordable tools to investigate these mechanisms.     

Acoustic Scattering in Flexible Waveguide Involving Step Discontinuity

In this paper, the propagation and scattering of acoustic waves in a flexible wave-guide involving step discontinuity at an interface is considered. The emerging boundary value problem is non-Sturm-Liouville and is solved by employing a hybrid mode-matching technique. The physical scattering process and attenuation of duct modes versus frequency regime and change of height is studied. Moreover, the mode-matching solution is validated through a series of numerical experiments by testifying the power conservation identity and matching interface conditions.     

ContPro: A web tool for calculating amino acid contact distances in protein from 3D -structures at different distance threshold

To investigate the functional sites on a protein and the prediction of binding sites (residues)in proteins, it is often required to identify the binding site residues at different distance threshold from protein three dimensional (3D)structures. For the study of a particular protein chain and its interaction with the ligand in complex form, researchers have to parse the output of different available tools or databases for finding binding-site residues. Here we have developed a tool for calculating amino acid contact distances in proteins at different distance threshold from the 3D-structure of the protein. For an input of protein 3D-structure, ContPro can quickly find all binding-site residues in the protein by calculating distances and also allows researchers to select the different distance threshold, protein chain and ligand of interest. Additionally, it can also parse the protein model (in case of multi model protein coordinate file)and the sequence of selected protein chain in Fasta format from the input 3D-structure. The developed tool will be useful for the identification and analysis of binding sites of proteins from 3D-structure at different distance thresholds. AVAILABILITY: IT CAN BE ACCESSED AT: http://procarb.org/contpro/     

From the female perspective: Long-term effects on quality of life of a program for women with asthma

Background: Although, among adults, asthma predominates in women, the role of sex and gender in asthma has only recently been studied. Moreover, only one study has focused on the management of asthma by women, reporting that 1 year subsequent to an intervention addressing sex and gender role factors, women's asthma status was improved.Objective: Data from a 2-year postintervention follow-up were assessed to determine whether there were longer-term effects on the asthma status and quality of life (QoL) of the participants.Methods: A randomized controlled design was used in which female patients with asthma, who were receiving services at the University of Michigan Health System, Ann Arbor, Michigan (2002-2006), were assigned to either a control group or a female-oriented intervention group that focused on management challenges related to sex and gender role factors. Data were collected at baseline and 2 years' postintervention (2008) by telephone interview and review of medical records. Measures included asthma-related QoL, health care and medication use for asthma, level of self-regulation, self-confidence in managing the condition, sex and gender role-related asthma problems, and days of missed work or school because of asthma. Data were analyzed using both generalized estimating equations logistic regression and log-linear regression.Results: The mean (SD) age of the 808 women participating in the study was 48.2 (13.1) years in the intervention group and 48.7 (14.3) years in the control group, and the percentage of minority participants was 15.8% and 16.3%, respectively. Despite randomization, women in the intervention group had more persistent asthma at baseline. At 2 years' postrandomization, the only significant difference in health care use was associated with scheduled office visits; no other significant health care use differences were evident. However, the women in the intervention group had a significantly greater decrease of asthma symptoms with sexual activity (P = 0.01) and greater reduction in days of work/school missed for asthma in winter months (P = 0.03), were better able to self-regulate (P = 0.01), were more confident in managing their asthma (P = 0.01), and had higher levels of asthma-related QoL (P = 0.02). They also had a greater reduction in the use of short-acting bronchodilators (ie, rescue medications) than did women in the control group (P ≤ 0.05).Conclusion: An intervention that focuses on female-specific aspects of asthma management may result in improved QoL and health status for women with asthma, as was evident 2 years' postintervention in this study.     

Ligand valency affects transcytosis, recycling and intracellular trafficking mediated by the neonatal Fc receptor

The neonatal Fc receptor (FcRn) transports IgG across epithelial cell barriers to provide maternal antibodies to offspring and serves as a protection receptor by rescuing endocytosed IgG and albumin from lysosomal degradation. Here we describe the generation of polarized Madin-Darby canine kidney (MDCK) cells expressing rat FcRn (rFcRn) to investigate the potential requirement for ligand bivalency in FcRn-mediated transport. The rFcRn-MDCK cells bind, internalize and bidirectionally transcytose the bivalent ligands IgG and Fc across polarized cell monolayers. However, they cannot be used to study FcRn-mediated transport of the monovalent ligand albumin, as we observe no specific binding, internalization or transcytosis of rat albumin. To address whether ligand bivalency is required for transport, the ability of rFcRn to transcytose and recycle wild-type Fc homodimers (wtFc; two FcRn-binding sites) and a heterodimeric Fc (hdFc; one FcRn-binding site) was compared. We show that ligand bivalency is not required for transcytosis or recycling, but that wtFc is transported more efficiently than hdFc, particularly at lower concentrations. We also demonstrate that hdFc and wtFc have different intracellular fates, with more hdFc than wtFc being trafficked to lysosomes and degraded, suggesting a role for avidity effects in FcRn-mediated IgG transport.     

Construction, affinity maturation, and biological characterization of an anti-tumor-associated glycoprotein-72 humanized antibody

The tumor-associated glycoprotein (TAG)-72 is expressed in the majority of human adenocarcinomas but is rarely expressed in most normal tissues, which makes it a potential target for the diagnosis and therapy of a variety of human cancers. Here we describe the construction, affinity maturation, and biological characterization of an anti-TAG-72 humanized antibody with minimum potential immunogenicity. The humanized antibody was constructed by grafting only the specificity-determining residues (SDRs) within the complementarity-determining regions (CDRs) onto homologous human immunoglobulin germ line segments while retaining two mouse heavy chain framework residues that support the conformation of the CDRs. The resulting humanized antibody (AKA) showed only about 2-fold lower affinity compared with the original murine monoclonal antibody CC49 and 27-fold lower reactivity to patient serum compared with the humanized antibody HuCC49 that was constructed by CDR grafting. The affinity of AKA was improved by random mutagenesis of the heavy chain CDR3 (HCDR3). The highest affinity variant (3E8) showed 22-fold higher affinity compared with AKA and retained the original epitope specificity. Mutational analysis of the HCDR3 residues revealed that the replacement of Asn(97) by isoleucine or valine was critical for the affinity maturation. The 3E8 labeled with (125)I or (131)I showed efficient tumor targeting or therapeutic effects, respectively, in athymic mice with human colon carcinoma xenografts, suggesting that 3E8 may be beneficial for the diagnosis and therapy of tumors expressing TAG-72.     

Safety and efficacy of transseptal puncture guided by real-time fusion of echocardiography and fluoroscopy

Aims

Visual guidance through echocardiography and fluoroscopy is crucial for a successful transseptal puncture (TSP) in a prespecified region of the fossa ovalis. The novel EchoNavigator system Release II (EchoNav II, Philips Healthcare, Andover, Massachusetts, USA) enables the real-time fusion of fluoroscopic and echocardiographic images. We evaluated this new imaging method in respect to safety and efficacy of TSP during MitraClip implantation and left atrial appendage closure.

Methods

Forty-four patients before (?EchoNav) and 44 patients after (+EchoNav) the introduction of real-time fusion were included in our retrospective, single-centre study. The primary endpoint was the occurrence of adverse events due to TSP. Secondary endpoints were successful puncture at the prespecified region and time until TSP (min).

Results

In both groups TSP was performed successfully in the prespecified region and no adverse events occurred during or due to the accomplishment of TSP. Time until TSP was significantly reduced in the +EchoNav group in comparison with the EchoNav group (18.48 ± 5.62?min vs. 23.20 ± 9.61?min, p = 0.006).

Conclusions

Real-time fusion of echocardiography and fluoroscopy proved to be as safe and successful as standard best practice for TSP. Moreover, efficacy was improved through significant reduction of time until TSP.