Synthetic Activity of Recombinant Whole Cell Biocatalysts Containing 2-Deoxy-D-ribose-5-phosphate Aldolase from Pectobacterium atrosepticum

In nature 2-deoxy-D-ribose-5-phosphate aldolase (DERA) catalyses the reversible formation of 2-deoxyribose 5-phosphate from D-glyceraldehyde 3-phosphate and acetaldehyde. In addition, this enzyme can use acetaldehyde as the sole substrate, resulting in a tandem aldol reaction, yielding 2,4,6-trideoxy-D-erythro-hexapyranose, which spontaneously cyclizes. This reaction is very useful for the synthesis of the side chain of statin-type drugs used to decrease cholesterol levels in blood. One of the main challenges in the use of DERA in industrial processes, where high substrate loads are needed to achieve the desired productivity, is its inactivation by high acetaldehyde concentration. In this work, the utility of different variants of Pectobacterium atrosepticum DERA (PaDERA) as whole cell biocatalysts to synthesize 2-deoxyribose 5-phosphate and 2,4,6-trideoxy-D-erythro-hexapyranose was analysed. Under optimized conditions, E. coli BL21 (PaDERA C-His AA C49M) whole cells yields 99 % of both products. Furthermore, this enzyme is able to tolerate 500 mM acetaldehyde in a whole-cell experiment which makes it suitable for industrial applications.     

Promising PLA‐functionalized MWCNT composites to use in nanotechnology

Films based on polylactic acid (PLA) reinforced with multi‐walled carbon nanotubes (MWCNT) were developed after using an excellent methodology to ensure an optimum dispersion of the filler in the matrix. The functionalization of MWCNT was carried out through a Fenton reaction to generate hydroxyl (OH) and carboxyl (COOH) groups on their walls. After that, COOH groups were lengthened by reacting with thionyl chloride and then with triethylene glycol to achieve a terminal OH distanced from the wall of the MWCNT. Nanocomposites based on PLA containing different concentrations of functionalized filler (fMWCNT: 0.026, 0.10, and 0.18 wt%) were prepared by casting. The influence of filler concentration was investigated using some techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), water vapor permeability (WVP) and uniaxial tensile mechanical properties. Excellent dispersion of fMWCNT was observed suggesting that the technique of functionalization used was appropriate. All nanocomposites presented great stability, allowing them to be processed to temperatures reaching 300°C. Furthermore, an increasing trend of ultimate tensile strength (σ_u) up to 20% and a decrease of WVP around 40% with the addition of only 0.10 wt% of fMWCNT were obtained. Considering these results, the new biodegradable nanocomposites developed in this work could be very promising to replace synthetic plastics that currently are used in different areas such as nanotechnology, packaging and biomedicine. POLYM. COMPOS., 37:3066–3072, 2016. © 2015 Society of Plastics Engineers     

Assessment of the Use of NaClO as an Alternative to H2O2 in the Oxidant-Titanium Ore-Simulated Solar Light System for Thiabendazole Degradation

Topics in Catalysis - The use of the magnetic fraction (MF) of a low-grade titanium ore (TO) and two oxidants (H2O2 and NaClO), testing each one separately, were compared in photo-Fenton like...     

Stability of viscoelastic liquid curtain

Thin liquid sheets occur in several practical applications. In curtain coating, a thin liquid sheet is formed and falls freely over a considerable height before it impinges onto a moving substrate. Precision curtain coating was developed for multi layer photographic films but its use has expanded to many different applications. One of the important limits of this process is the stability of the liquid curtain, which may define the minimal thickness that can be coated at a given web speed.The condition at which a low viscosity Newtonian liquid curtain breaks was first derived based on a simple balance between inertial and capillary forces. There is a critical flow rate below which the curtain becomes unstable. For viscoelastic liquids, the normal stress related to the stretching of polymer molecules as the liquid accelerates down the curtain changes the force balance. Here, the critical condition at which a viscoelastic liquid curtain breaks was determined as a function of the rheological properties of the liquid. The results show that high extensional viscosity liquids create more stable curtains. Liquid additives could be used to push the limits of curtain flow rates to smaller values and consequently to widen the operability window of the process.     

A study on the mechanical strength of Fe2O3/Cr2O3/CuO catalyst for high temperature water gas shift reaction

Journal of Porous Materials - The present study aims to investigate the effects of iron (hydr)oxide phases formed during precipitation and the addition of different binders on the mechanical and...     

Heterogeneity in Youth Symptom Trajectories Following Psychiatric Crisis: Predictors and Placement Outcome.

The authors examined heterogeneity in symptom trajectories among youths following psychiatric crises as well as the psychosocial correlates and placement outcomes associated with identified trajectories. Using semiparametric mixture modeling with 156 youths approved for psychiatric hospitalization, the authors identified 5 trajectories based on symptoms over the 16 months following crisis: high improved, high unimproved, borderline improved, borderline unimproved, and subclinical. Membership in unimproved symptom groups was associated with less suicidality, younger age, more youth hopelessness, and more caregiver empowerment. Improved symptom group membership predicted long-term decreases in days in out-of-home placements. More important, and in contrast with general impressions from the existing literature, findings suggest that a substantive proportion of youths with serious emotional disturbance sustain high levels of symptomatology following intensive mental health services. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Regulating the geological sequestration of CO2

Governments worldwide should provide incentives for initial large-scale GS projects to help build the knowledge base for a mature, internationally harmonized GS regulatory framework. Health, safety, and environmental risks of these early projects can be managed through modifications of existing regulations in the EU, Australia, Canada, and the U.S. An institutional mechanism, such as the proposed Federal Carbon Sequestration Commission in the U.S., should gather data from these early projects and combine them with factors such as GS industrial organization and climate regime requirements to create an efficient and adaptive regulatory framework suited to large-scale deployment. Mechanisms to structure long-term liability and fund long-term postclosure care must be developed, most likely at the national level, to equitably balance the risks and benefits of this important climate change mitigation technology. We need to do this right. During the initial field experiences, a single major accident, resulting from inadequate regulatory oversight, anywhere in the world, could seriously endanger the future viability of GS. That, in turn, could make it next to impossible to achieve the needed dramatic global reductions in CO2 emissions over the next several decades. We also need to do it quickly. Emissions are going up, the climate is changing, and impacts are growing. The need for safe and effective CO2 capture with deep GS is urgent.     

Synthesis of an organic semiconductor by polimerization of 3-amino-1,2,4-triazole

We performed the polymerization of 3-amino-1,2,4-triazole (ATA), an insulator material, in acidic aqueous solution with ammonium persulfate, as oxidant agent. The new material, conveniently doped, turned out to be a semiconductor tetramer. The characterization was carried out using physical and spectroscopic techniques (elemental analysis, infrared spectroscopy, ¹H NMR, ¹³C NMR and mass spectra). Thermogravimetric analysis (TGA) indicated that this oligomer enhances thermal stability of starting material. The room temperature electrical conductivity of the synthesized oligomer (OATA) was 3.1 × 10⁻⁴ S cm⁻¹.The kinetic polymerization was analyzed by UV–vis spectroscopy, taking into account the pH dependence, monomer–oxidant ratio and monomer concentration. A possible polymerization mechanism was proposed.     

An efficient group key management protocol using code for key calculation: CKC

This paper presents a new group key management protocol, CKC (Code for Key Calculation) for secure IP multicast. In this protocol which is based on logical key hierarchy, only the group key needs to be sent to new member at join. Then, using the group key current members and the new member calculate the necessary keys by node codes and one-way hash function. A?node code is a random number assigned to each node to help users calculate necessary keys. Again, at leave server just sends the new group key to the remaining members. By this key, members calculate necessary keys using node codes and one-way hash function. The security of the keys is based on one-wayness of hash function. The results show that CKC reduces computational and communication overhead, and message size largely at join without increasing them at leave.     

A traditional cheese from Greece to Turkey: Armola

In the present study, red capia pepper, broccoli, pumpkin, carrot purees and a probiotic culture containing Lactobacillus acidophilus were added to the conventionally produced Armola cheese to improve the functional properties of the cheese. The analyses showed that there were significant differences between the physicochemical and functional properties of the cheese samples. The samples containing broccoli had the highest antioxidant activity. Except for the control sample, L. acidophilus counts in Armola cheese samples were found to be 10⁶ log cfu/g on day 30 and the samples were found to maintain their probiotic properties until the end of the storage period.