Effect of alkali cation type on the plasticizing effect of ligno-sulfonate in alkali-activated systems

The rheological properties of alkali-activated systems are significantly affected by the nature of the alkaline activator. Hydroxide-activated systems’ workability is typically lower than that of alkali-activated systems but can be improved by lignosulfonate plasticizer. However, the lignosulfonate plasticizer’s effectivity depends on the dosage of lignosulfonate, the nature of hydroxide and pH of their solutions. Therefore, in this study, the effectiveness of lignosulfonate plasticizer with respect to alkali ion type (Na+, K+, Li+) in alkali hydroxide-activated systems based on ground granulated blast furnace slag was evaluated. The concentration of the alkaline activator (NaOH, KOH and LiOH) was the same in all cases of 4M. The superplasticizer dosage was 0%, 0.5% and 1.0% of dry matter of lignosulfonate plasticizer to the slag weight. Rheological properties were determined using a rotational rheometer equipped with vane in-cup geometry working in oscillation amplitude sweep mode, from which critical strain and corresponding viscoelastic variables were obtained.

Cleaning of concentrated emulsion sewage of electric-weld pipe lines

Existing processes of cleaning emulsion sewage are based on either physicochemical technology with application of complex of reagents – nonorganic electrolytes and organic flocculants, resulting in obtaining highly-mineralized purified water, which cannot be used for technical water supply, or based on complicated technologies of electrocoagulation and ultrafiltration. This required elaboration of a new technology and equipment for cleaning concentrated emulsion sewage, in particular, those containing emulsol of Wedolit EP-5 grade, used for hydro-mechanical expanders of electric-weld pipe lines. The technology stipulates a successive introduction of a reagent – suspension of alumo-silicate based hard-phased sorbent and solution of flocculant of cation type Praestol-650ВС – into emulsion sewage, their mixing with emulsion water in a definite mode, sedimental differentiation of the formed phases in a precipitator-flocculator “ЭП ОФ”, gravitation concentration and dewatering of the obtained sediment at vacuumfilter. The dewatered sediment can be utilized in cement industry and metallurgy. It was shown that application of the hard-phase sorbent does not result in an increase of mineralization of purified water and enables to use it for technical purposes. The group of companies “ECO-PROJECT”, Ekaterinburg, accomplished a project for Chelyabinsk pipe-rolling plant, elaboration and manufacturing of equipment, as well as commissioning and start-up of the equipment. The elaborated technical solutions in the process of equipment running showed a high efficiency and can be used as a base for creation of facilities of any productivity for cleaning multi-type emulsion sewage at enterprises of various industries.

Prediction of Sulfate Attack Products in Portland-Limestone Cements: The Effect of Cation Type and Concentration

Portland-limestone cement materials are susceptible to sulfate attack at low temperature and high humidity, because such conditions facilitate the formation of thaumasite, detriment to the structural integrity of calcium silicate hydrates (C─S─H). In this work, the effect of the cation associated with sulfates, concentration of sulfate solution, and limestone content in cement, were thermodynamically simulated. MgSO4 solution is of higher risk, degrading extensively the structural integrity of C─S─H. Although this phase is partially preserved under the effect of Na2SO4 and K2SO4 solutions, extensive expansion and thaumasite formation occur. The sulfate content of the corrosive solution and the limestone content in cement are the factors mostly intensifying the attack caused by MgSO4 and Na2SO4/K2SO4 solutions, respectively.

PROGNOSTIC OUTCOME IN SUBAXIAL CERVICAL SPINE INJURIES MANAGEMENT BY ANTERIOR CERVICAL DYNAMIC PLATE WITH CAGE/GRAFT FIXATION AND POSTERIOR CERVICAL LATERAL MASS SCREW-ROD FIXATION METHODS

Introduction: The anterior cervical decompression and fusion (ACDF)procedures, especially in cases requiring decompression of two or more levels. Routine use for the treatment of cervical spondylosis has caused plate design to change signicantly in recent years. Aim: To estimate the incidence of sub axial cervical trauma patients admitted in the Neurosurgery wards of the institute. To study the therapeutic outcome after management of the subaxial cervical trauma cases by Anterior cervical decompression (discectomy/corpectomy) with graft or cage and dynamic plate xation, posterior lateral mass screw-rod xation, bidirectional single stage combined approach techniques. To compare anterior dynamic plate graft xation with the posterior lateral mass screw rod xation in cases that could be managed by any single approach. Material and methods: This non randomized prospective observational study was conducted in the Department of Neurosurgery, Mahatma Gandhi Medical College & Hospital, Jaipurfrom April 2018 to December 2019. All diagnosed cases of subaxial cervical spine attending and being admitted to our institute during the study period and treated by anterior cervical decompression with dynamic plate xation, posterior lateral mass screw rod xation or combined technique were included in the study. Result:According to AO Spine Classication Type, 10(20.8%) patients had A2, 15(31.3%) patients had A3, 8(16.7%) patients had A4, 1(2.1%) patient had B2, 13(27.1%) patients had C and 1(2.1%) patient had C,F4. It was found that in Non Severe group, 6(31.6%) patients had A3type in AO Spine Classication Type and in severe group 9(31.0%) patients had A3type in AO Spine Classication Type. In Non Severe group, 4(21.1%) patients had C type in AO Spine Classication Type and in Severe group 9(31.0%) patients had C type in AO Spine Classication Type. The association between AO Spine Classication Type vs ASIAImpairment Scale Group was not statically signicant (p=0.6887). Conclusion:In ASIA IMPAIRMENT SCALE GROUP, 5 SLICS1 was higher [6(31.6%)] in Non Severe group and 8 SLICS1 was higher [9(31.0%)] in Severe group which was not statically signicant (p=0.4820).The mean EQ5D post op at 6month of Non Severe (ASIA IMPAIRMENTSCALE) patients was higher than the Severe group of patients which wasstatically signicant (p=0.0442).

Insight into formation propensity of pseudocircular DNA G-hairpins

We recently showed that Saccharomyces cerevisiae telomeric DNA can fold into an unprecedented pseudocircular G-hairpin (PGH) structure. However, the formation of PGHs in the context of extended sequences, which is a prerequisite for their function in vivo and their applications in biotechnology, has not been elucidated. Here, we show that despite its ‘circular’ nature, PGHs tolerate single-stranded (ss) protrusions. High-resolution NMR structure of a novel member of PGH family reveals the atomistic details on a junction between ssDNA and PGH unit. Identification of new sequences capable of folding into one of the two forms of PGH helped in defining minimal sequence requirements for their formation. Our time-resolved NMR data indicate a possibility that PGHs fold via a complex kinetic partitioning mechanism and suggests the existence of K+ ion-dependent PGH folding intermediates. The data not only provide an explanation of cation-type-dependent formation of PGHs, but also explain the unusually large hysteresis between PGH melting and annealing noted in our previous study. Our findings have important implications for DNA biology and nanotechnology. Overrepresentation of sequences able to form PGHs in the evolutionary-conserved regions of the human genome implies their functionally important biological role(s).