Urease-aided calcium carbonate mineralization for engineering applications : a review

Inducing calcium carbonate precipitation is another important function of urease in nature. The process takes advantage of the supply of carbonate ions derived from urea hydrolysis and of an increase in pH generated by the reaction, effects that in the presence of Ca2+ ions lead to the precipitation of CaCO3. Further to its importance in nature, if performed in a biomimetic manner, the urease-aided CaCO3 mineralization offers enormous potential in innovative engineering applications as an eco-friendly technique operative under mild conditions, to be used for remediation and cementation/deposition in field applications in situ. These include among others, the strengthening and consolidation of soil/sand, the protection and restoration of stone and concrete structures, conservation of stone cultural heritage materials, cleaning waste- and groundwater of toxic metals and radionuclides, and plugging geological formations for the enhancement of oil recovery and geologic CO2 sequestration. In view of the potential of this newly emerging interdisciplinary branch of engineering, this article presents the principles of urease-aided calcium carbonate mineralization apposed to other biomineralization processes, and reviews the advantages and limitations of the technique compared to the conventional techniques presently in use. Further, it presents areas of its existing and potential applications, notably in geotechnical, construction and environmental engineering, and its future perspectives. Keywords: Urease, CaCO3, Biomineralization, Soil and sand, Construction materials, Groundwate

Enzyme immobilization by adsorption : a review

Endowed with unparalleled high catalytic activity and selectivity, enzymes offer enormous potential as catalysts in practical applications. These applications, however, are seriously hampered by enzymes’ low thermal and chemical stabilities. One way to improve these stabilities is the enzyme immobilization. Among various tested methods of this process that make use of different enzyme-carrier interactions, immobilization by adsorption on solid carriers has appeared most common. According to these findings, in this review we present a comparative analysis of the literature reports on the recent trends in the immobilization of the enzymes by adsorption. This thorough study was prepared in order to provide a deeper understanding of the process. Both carriers, carrier modifiers and procedures developed for effective adsorption of the enzymes are discussed. The review may thus be helpful in choosing the right adsorption scheme for a given enzyme to achieve the improvement of its stability and activity for a specific application

Cele polityki ekologicznej Polski i Unii Europejskiej z uwzględnieniem gospodarki leśnej

The article contains an analysis of the primary terms and notions such as politics. Ecological politics, ecology, forest management, and basic information concerning the ecological policy in Poland and in the European Union

Temperature- and pressure-dependent stopped-flow kinetic studies of jack bean urease : implications for the catalytic mechanism

Urease, a Ni-containing metalloenzyme, fea- tures an activity that has profound medical and agricultural implications. The mechanism of this activity, however, has not been as yet thoroughly established. Accordingly, to improve its understanding, in this study we analyzed the steady-state kinetic parameters of the enzyme (jack bean), K M and k cat , measured at different temperatures and pres- sures. Such an analysis is useful as it provides information on the molecular nature of the intermediate and transition states of the catalytic reaction. We measured the parame- ters in a noninteracting buffer using a stopped-flow tech- nique in the temperature range 15–35 ° C and in the pressure range 5–132 MPa, the pressure-dependent mea- surements being the first of their kind performed for urease. While temperature enhanced the activity of urease, pres- sure inhibited the enzyme; the inhibition was biphasic. Analyzing K M provided the characteristics of the formation of the ES complex, and analyzing k cat , the characteristics of the activation of ES. From the temperature-dependent measurements, the energetic parameters were derived, i.e. thermodynamic D H o and D S o for ES formation, and kinetic D H = and D S = for ES activation, while from the pressure- dependent measurements, the binding D V b and activation D V 6 ¼ cat volumes were determined. The thermodynamic and activation parameters obtained are discussed in terms of the current proposals for the mechanism of the urease reaction, and they are found to support the mechanism proposed by Benini et al. ( Structure 7:205–216; 1999), in which the Ni–Ni bridging hydroxide—not the terminal hydroxide—is the nucleophile in the catalytic reaction

The morphological evaluation of the homograft wall in an electron microscopic study

Cases of massive purulent infection of vascular prosthesis are demonstrated in this study. Infected prosthesis was substituted by arterial homograft, harvested during multi-organ procurement, and stored by the cold ischaemia method. In the follow-up period, the patients were divided into two groups, those treated with immunosuppression (n = 16) and those treated without immunosuppressive drugs (n = 13). The patients underwent resurgery, during which a fragment of arterial wall was taken for electron microscopic examination. In the group with immunosuppression, the presence of the following structures was observed: endothelial cells, the intima, with a great number of elastic and collagen fibrils with fibrinogen inclusions, and active phagocyting myoblasts and myofibroblasts. In the group without immunosuppression electron microscopic examination showed the total destruction of the wall of the ruptured arterial homograft - absence of endothelium and sparse, damaged fibroblasts of the media or their degraded fragments, making a picture of cellular death. Morphological analysis of the arterial wall and the clinical state of the patient suggest the necessity of immunosuppressive treatment after fresh arterial homograft transplantation

Analiza kliniczna wydalania jodu z moczem u chorych na zróżnicowane raki tarczycy w trakcie terapii L-tyroksyną

Introduction: Urinary iodine concentrations were analyzed in the morning urine samples of patients with differentiated thyroid cancer (DTC). Material and methods: The analyzed group included 572 DTC patients who were treated with radioiodine or hospitalized for evaluation of radioiodine treatment effects in 2009 at the Institute of Oncology in Gliwice. Ioduria was analyzed by PAMM (Program Against Micronutrient Malnutrition) method before rhTSH administration. A total of 545 tests were performed during L-thyroxine treatment and 27 after L-thyroxine withdrawal. Results: Median L-thyroxine dose was 150 &#956;g/day. Median ioduria was 127.5 &#956;g/L during L-thyroxine therapy and 134 &#956;g/L after the L-thyroxine withdrawal. No distinct relation between ioduria and L-thyroxine dose was observed. Ioduria < 200 &#956;g/L was observed in over 90% of patients and this cut-off was chosen for the reference range. Only 1.2% of patients showed a distinct stable iodine contamination (ioduria &#8805; 300 &#956;g/L). Conclusions: Urinary iodine concentrations in differentiated thyroid cancer patients treated with L-thyroxine vary in a wide range and do not show a clear relation with L-thyroxine dose. (Pol J Endocrinol 2010; 61 (5): 458-461)Wstęp: W pracy przeanalizowano stężenie jodu w porannej próbce moczu u chorych na zróżnicowanego raka tarczycy (DTC, differentiated thyroid cancer). Materiały i metody: Badano 572 chorych na DTC po operacji, którzy w 2009 roku byli hospitalizowani w celu leczenia jodem radioaktywnym lub oceny jego wyników. Stężenie jodu w moczu oznaczano metodą PAMM (Program Against Micronutrient Malnutrition). W trakcie leczenia L-tyroksyną wykonano 545 badań, 27 po przerwie w stosowaniu L-tyroksyny. Wyniki: Mediana dawki L-tyroksyny wynosiła 150 &#956;g/dzień. Mediana dobowego wydalania jodu z moczem wynosiła 127,5 &#956;g/L, a po odstawieniu L-tyroksyny 134 &#956;g/L. Nie obserwowano zależności stężenia jodu w moczu od stosowanej dawki tyroksyny. Jodurię < 200 &#956;g/L obserwowano u ponad 90% chorych i ten zakres uznano za referencyjny. Kontaminację stabilnym jodem wykazano u 1,2% (joduria &#8805; 300 &#956;g/L). Wnioski: Stężenia jodu w moczu u chorych na zróżnicowanego raka tarczycy, leczonych L-tyroksyną, wahają się w szerokim przedziale wartości i nie korelują z dawką L-tyroksyny. (Endokrynol Pol 2010; 61 (5): 458-461

Increased Progression-Free Survival with Cabozantinib Versus Placebo in Patients with Radioiodine-Refractory Differentiated Thyroid Cancer Irrespective of Prior Vascular Endothelial Growth Factor Receptor-Targeted Therapy and Tumor Histology: A Subgroup Analysis of the COSMIC-311 Study

Cabozantinib; Follicular; Thyroid cancerCabozantinib; Fol·licular; Càncer de tiroidesCabozantinib; Folicular; Cáncer de tiroidesBackground: Lenvatinib and sorafenib are standard of care first-line treatments for advanced, radioiodine-refractory (RAIR) differentiated thyroid cancer (DTC). However, most patients eventually become treatment-resistant and require additional therapies. The phase 3 COSMIC-311 study investigated cabozantinib in patients with RAIR DTC who progressed on lenvatinib, sorafenib, or both and showed that cabozantinib provided substantial clinical benefit. Presented in this study is an analysis of COSMIC-311 based on prior therapy and histology. Methods: Patients were randomized 2:1 (stratification: prior lenvatinib [yes/no]; age [≤65, >65 years]) to oral cabozantinib (60 mg tablet/day) or matched placebo. Eligible patients received 1–2 prior vascular endothelial growth factor receptor-targeting tyrosine kinase inhibitors for DTC (lenvatinib or sorafenib required), had a confirmed DTC diagnosis, and were refractory to or ineligible for radioiodine therapy. For this analysis, progression-free survival (PFS) and objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 by a blinded independent radiology committee were evaluated by prior therapy (lenvatinib only, sorafenib only, both) and histology (papillary, follicular, oncocytic, poorly differentiated). Results: Two hundred fifty-eight patients were randomized (170 cabozantinib/88 placebo) who previously received sorafenib only (n = 96), lenvatinib only (n = 102), or both (n = 60). The median follow-up was 10.1 months. The median PFS (months) with cabozantinib/placebo was 16.6/3.2 (sorafenib only: hazard ratio [HR] 0.13 [95% confidence interval, CI, 0.06–0.26]), 5.8/1.9 (lenvatinib only: HR 0.28 [95% CI 0.16–0.48]), and 7.6/1.9 (both: HR 0.27 [95% CI 0.13–0.54]). The ORR with cabozantinib/placebo was 21%/0% (sorafenib only), 4%/0% (lenvatinib only), and 8%/0% (both). Disease histology consisted of 150 papillary and 113 follicular, including 43 oncocytic and 36 poorly differentiated. The median PFS (months) with cabozantinib/placebo was 9.2/1.9 (papillary: HR 0.27 [95% CI 0.17–0.43]), 11.2/2.5 (follicular: HR 0.18 [95% CI 0.10–0.31]), 11.2/2.5 (oncocytic: HR 0.06 [95% CI 0.02–0.21]), and 7.4/1.8 (poorly differentiated: HR 0.18 [95% CI 0.08–0.43]). The ORR with cabozantinib/placebo was 15%/0% (papillary), 8%/0% (follicular), 11%/0% (oncocytic), and 9%/0% (poorly differentiated). Safety outcomes evaluated were consistent with those previously observed for the overall population. Conclusions: Results indicate that cabozantinib benefits patients with RAIR DTC, regardless of prior lenvatinib or sorafenib treatments or histology. Clinical Trial Registration Number: NCT03690388.This work was supported by Exelixis, Inc., Alameda, CA (no grant number). Exelixis was involved in the study design, the collection, analysis, and interpretation of data, the writing of the report, and the decision to submit for publication