Recovery of Formic Acid and Acetic Acid from Waste Water Using Reactive Distillation

Processing of biobased feedstock materials may lead to formation of multicomponent azeotropic mixtures. Reactive separations provide an opportunity to circumvent azeotropes by changing the substance properties through chemical reactions. Exemplarily several effluents from black liquor processing contain aqueous mixtures of low molecular weight fatty acids such as formic acid and acetic acid. These mixtures form inseparable azeotropes. Separation of the system formic acid–acetic acid–water by esterification with methanol was investigated. Reactive distillation experiments in batch and continuous mode confirmed complete removal of formic acid in a first step. Acetic acid may then be isolated by distillation or by reactive distillation.     

Resin luting materials: Tissue response in dog's teeth

The aim of this study was to evaluate radiographically and histologically the pulpal and periapical response to self‐adhesive (Rely X? Unicem) and self‐etching and self‐curing (Multilink^®) resin‐based luting materials in deep cavities in dogs' teeth. Deep class V cavities (0.5‐mm–thick dentin) were prepared in 60 canine premolars and the following materials were applied on cavity floor: Groups I/V—RelyX? Unicem; Groups II/VI—Multilink^®; Groups III/VII—zinc phosphate cement (control) and; Groups IV/VIII—gutta‐percha (control). Cavities were restored with silver amalgam. Animals were euthanized after 10 days (groups I–IV) and 90 days (groups V–VIII). Tooth/bone blocks were radiographed and processed for histopathological evaluation of pulp and periapical tissue response to the materials. All materials presented similar histopathological features and radiographic findings at both periods. The pulp tissue was intact. The apical and periapical regions and periodontal ligament thickness were normal. No inflammatory cells, resorption of mineralized tissue (dentin, cementum, and alveolar bone) or bacteria were observed. The lamina dura was intact and no areas of periapical bone rarefaction or internal/external root resorption were observed radiographically. It can be concluded that Rely X? Unicem and Multilink^® caused no adverse tissue reactions and may be indicated for cementation of indirect restorations in deep dentin cavities without pulp exposure. Microsc. Res. Tech. 78:1098–1103, 2015. © 2015 Wiley Periodicals, Inc.     

Complementary Co‐assembling Peptides: From In Silico Studies to In Vivo Application

Self‐assembling biomaterials offer an unprecedented chance of successfully facing most of the challenges of various biomedical fields, and, in particular, of tissue engineering. Nonetheless co‐assembling peptides (CAPs), taking advantage of the theory and empirical findings developed for self‐assembling peptides, could provide an even better control over cell cultures, drug delivery, and transplantation therapies. This study follows a “full” bottom‐up approach to develop new CAPs for neural tissue engineering applications. After molecular aggregation analysis via coarse‐grained simulations, LKLK12, LDLD12, and the functionalized KLPGWSG‐LDLD12 CAPs are synthesized and characterized assessing their co‐assembled secondary structures, the biomechanical properties of the obtained hydrogels, and the morphological features of the assembled nanofibers. The biological influence on viability and differentiation of human and murine neural stem cells are tested in vitro and neuroregenerative potentials in complete spinal cord transections are verified in vivo. Upon mixing of CAPs, the spontaneous formation of double layers of β‐sheets with a high degree of integration of the two CAP species is demonstrated. The formation of entangled nanofibrous structures give rise to shear‐thinning hydrogels. The in vitro results are comparable to a standard state‐of‐the‐art cell culture substrate and nervous regeneration in vivo is enhanced.     

Integration of binding peptide selection and multifunctional particles as tool-box for capture of soluble proteins in serum

In this paper, we report on a general approach for the detection of a specific tumoural biomarker directly in serum. Such detection is made possible using a protein-binding peptide selected through an improved phage display technique and then conjugated to engineered microparticles (MPs). Protein biomarkers represent an unlimited source of information for non-invasive diagnostic and prognostic tests; MP-based assays are becoming largely used in manipulation of soluble biomarkers, but their direct use in serum is hampered by the complex biomolecular environment. Our technique overcomes the current limitations as it produces a selective MP—engineered with an antifouling layer—that ‘captures’ the relevant protein staying impervious to the background. Our system succeeds in fishing-out the human tumour necrosis factor alpha directly in serum with a high selectivity degree. Our method could have great impact in soluble protein manipulation and detection for a wide variety of diagnostic applications.     

Modeling survival of high hydrostatic pressure treated stationary- and exponential-phase Listeria innocua cells

High Hydrostatic Pressure (HHP) inactivation (325–400 MPa; 0–20 min; maximum temperature 30 °C) of cells of Listeria innocua CECT 910 was studied in two different growth phases (exponential and stationary), and the corresponding survival curves were obtained for each case. The curves were fitted to two nonlinear models, the modified Gompertz equation and the Baranyi model. The kinetic constants calculated for both models, µ_max and k_max, indicated that cells in exponential growth phase were more sensitive to pressure than those in stationary phase. Both mathematical models were suitable for describing L. innocua HHP survival curves, rendering kinetic constants that increased with increasing pressure. When considering the experimental models validation, both Gompertz and Baranyi predicted in a similar way, however Baranyi had slightly lower A_f (Accuracy factor) and B_f (Bias factor) values, which indicated better prediction values. In summary, both mathematical models were perfectly valid for describing L. innocua inactivation kinetics under HHP treatment.Industrial relevanceThe mathematical models for inactivation and growth of microorganisms are the foundation of predictive microbiology and are used in risk assessments procedures as part of the food safety management system. Besides, these models together with those applied to inactivation of enzymes and destruction of quality factors are essential to optimize processes and thus to lay the foundations for industrial processing. It is therefore necessary to identify generally applicable kinetic models that will produce primary and secondary kinetic parameters and are statistically reliable as a key tool to predict the behaviour of microorganisms, enzymes and quality factors after processing.     

Influence of vitrified bond structure on radial wear of cBN grinding wheels

This paper presents the results of research concerning the radial wear of super hard grinding wheels in the process of internal grinding of bearing rings. The new-developed grinding wheel is designed for bonding the abrasive grains of submicrocrystalline boron nitride using a glass–ceramic bond. This grinding wheel is compared to cBN grinding wheels composed from ceramic bonding systems, currently having application in industry. A crystalline phase from a group of single-diagonal pyroxenes of an XYSi₂O₆ type was generated at the glass–ceramic bond from a CaO–MgO–Al₂O₃–B₂O₃–SiO₂ system. An influence of the presence of this phase on the bond fracture toughness coefficient K_Ic and the elastic modulus E of cBN grinding wheels was examined. Compared to grinding wheels comprising the commercial bond from a Na₂O–K₂O–Al₂O₃–B₂O₃–SiO₂ system, the microcrystalline structure of the new-developed bond limits the range of its fragmentation in the process of grinding. It exerts a marked influence on the formation of different roughness profiles on the wheel working surface and the wear resistance, compared to a grinding wheel composed from a commercial bond.