A systematic study on sustainable low carbon cement - Superplasticizer interaction: Fresh, mechanical, microstructural and durability characteristics.

As governments around the world take on ambitious construction projects, from housing to infrastructure to transportation, the demand for cement is set to rise. It is anticipated that global cement production is set to achieve a compound annual growth rate of ∼5.1% for the years 2022-2025. The negative impact of cement production on the environment, such as carbon emissions and energy consumption, is also well known. This instigates the need to look for alternative and sustainable supplementary cementitious materials (SCMs) such as Fly ash (FA), Limestone (LS), Metakaolin (MK), Ground granulated blast furnace slag (GGBFS) and Silica fume (SF) which when blended with Portland clinker result in lower carbon emissions and better end products. With expanding cement demand, the need for chemical admixtures has also increased. This comprehensive study focuses on the compatibility of commercially available superplasticizers with SCMs blended low carbon cement and their influence on fresh and hardened properties along with microstructural and durability aspects. The chemistry of superplasticizers and how it effects the hydration mechanism of blended cement are also highlighted in detail. Moreover, the effect of different types of superplasticizers, their dosage, water binder ratio, and details of experiments used by other authors are also discussed and listed. As cementitious matrix containing any kind of SCM such as FA showed better environmental performance on the basis of life cycle assessment which was due to carbon emission factor (ξi). For cement, ξi was 311.27 kg CO2-eq/t, whereas for FA it was much lower (8.70 kg CO2-eq/t). Based on this comprehensive literature review, current challenges for the utilisation of waste SCMs incorporating superplasticizers along with research gap have been identified. Apart from this, the ongoing research work on the effect of chemical and mineral admixture on Limestone-calcined clay cement (LC3) using statistical modelling to optimize the mix is also discussed. It was observed that the use of a specific type of mineral admixture with a superplasticizer inversely affected the mechanical properties like compressive strength and modulus of rupture but improved the water-binder ratio, porosity, and water absorption.

Arm impairment and walking speed explain real-life activity of the affected arm and leg after stroke.

OBJECTIVE: To determine to what extent accelerometer-based arm, leg and trunk activity is associated with sensorimotor impairments, walking capacity and other factors in subacute stroke. DESIGN: Cross-sectional study. PATIENTS: Twenty-six individuals with stroke (mean age 55.4 years, severe to mild motor impairment). METHODS: Data on daytime activity were collected over a period of 4 days from accelerometers placed on the wrists, ankles and trunk. A forward stepwise linear regression was used to determine associations between free-living activity, clinical and demographic variables. RESULTS: Arm motor impairment (Fugl-Meyer Assessment) and walking speed explained more than 60% of the variance in daytime activity of the more-affected arm, while walking speed alone explained 60% of the more-affected leg activity. Activity of the less-affected arm and leg was associated with arm motor impairment (R2 = 0.40) and independence in walking (R2 = 0.59). Arm activity ratio was associated with arm impairment (R2 = 0.63) and leg activity ratio with leg impairment (R2 = 0.38) and walking speed (R2 = 0.27). Walking-related variables explained approximately 30% of the variance in trunk activity. CONCLUSION: Accelerometer-based free-living activity is dependent on motor impairment and walking capacity. The most relevant activity data were obtained from more-affected limbs. Motor impairment and walking speed can provide some information about real-life daytime activity levels.

Layer-Stacking-Driven Fluorescence in a Two-Dimensional Imine-Linked Covalent Organic Framework.

Schiff-condensation reactions carried out between 1,6-diaminopyrene (DAP) and the tritopical 1,3,5 benzenetricarbaldehyde (BTCA) or 2,4,6-triformylphloroglucinol (TP) ligands give rise to the formation of two-dimensional imine-based covalent-organic frameworks (COFs), named IMDEA-COF-1 and -2, respectively. These materials show dramatic layer-packing-driven fluorescence in solid state arising from the three-dimensional arrangement of the pyrene units among layers. Layer stacking within these 2D-COF materials to give either eclipsed or staggered conformations can be controlled, at an atomic level through chemical design of the building blocks used in their synthesis. Theoretical calculations have been used to rationalize the different preferential packing between both COFs. IMDEA-COF-1 shows green emission with absolute photoluminescence quantum yield of 3.5% in solid state. This material represents the first example of imine-linked 2D-COF showing emission in solid state.

Macro invertebrate community from Sonamarg streams of Kashmir Himalaya.

This study analyses a macroinvertebrate community survey for River Sindh and its tributary including Baltal, Yashmarg, Sonamarg and Thajwas Grar considering the extreme hydrological conditions linked with the seasonal low-flow period typical for some streams in this area. This study attempts to provide an overview of the macro invertebrate assemblages and physico-chemical variables of the River Sindh and its important tributary. Four study sites were selected from the River Sindh and its tributary including Baltal, Yashmarg, Sonamarg and Thajwas Grar for studying the ecological distribution of Macroinvertebrate assemblages. Totally, 33 taxa of macroinvertebrates were recorded from the two streams belonging to Mollusca-3 (Gastropoda-2 and Bivalvia-1), Annelida-1 and Arthropoda-29 (Insecta-29). Among insects Ephemeroptera (7), Trichoptera (6) and Diptera (13) dominated. Except Yashmrag all sites were found devoid of annelids while as the mollusks were found absent at Sonamarg. Highest values of Shannon Weiner Index were found at Yashmarg (2.42) and lowest at Sonamarg (1.99) while as highest and lowest Sorensen's similarity coefficient were found between Baltal/Thajwas Grar (0.68) and Yashmarg/Thajwas Grar (0.39), respectively. A perusal of the data on physico-chemical characteristics showed that these streams were hard water type with high dissolved oxygen content. The ionic composition of the stream waters revealed the predominance of bicarbonate and calcium. Insecta dominated both qualitatively as well as quantitatively and the study revealed that the substrate compositions dominated by gravel, pebble and leaf litters are primary determinants of the invertebrate community structure recording maximum species diversity and abundance. Sample locations impacted by Amarnath yatris pilgrimage comparatively reflected slightly higher increase in nutrients than Thajwas Grar almost devoid of pilgrimage effect.

Meta-analysis: endoscopic variceal ligation for primary prophylaxis of oesophageal variceal bleeding.

BACKGROUND: The treatment effects of primary prophylactic endoscopic variceal ligation are unclear. AIM: To compare the treatment effects of endoscopic variceal ligation and beta-blockers for primary prophylaxis of oesophageal variceal bleeding. In addition, a subgroup analysis was done with the purpose to delineate differences in the effects of intervention that were biologically based. METHODS: We performed a literature search for randomized controlled trials, which compared the treatment effects of endoscopic variceal ligation with beta-blockers for primary prophylaxis of oesophageal variceal bleeding. Of the 955 articles screened, eight randomized-controlled trials including 596 subjects (285 with endoscopic variceal ligation and 311 with beta-blockers) were analysed. Outcomes measures evaluated were first gastrointestinal bleed, first variceal bleed, all-cause deaths, bleed-related deaths and severe adverse events. The measure of association employed was relative risk; with heterogeneity and sensitivity analyses. RESULTS: Variceal obliteration was obtained in 261 (91.6%) patients and target beta-blockers therapy was achieved in 294 (94.5%) patients (P = 0.19). Endoscopic variceal ligation compared with beta-blockers significantly reduced rates of first gastrointestinal bleed by 31% (RR, 0.69; 95% CI: 0.49-0.96; P = 0.03; NNTB = 15) and first variceal bleed by 43% (RR, 0.57; 95% CI: 0.38-0.85; P = 0.0067; NNTB = 11). All-cause deaths and bleed-related deaths were unaffected (RR, 1.03; 95% CI: 0.79-1.36; P = 0.81 and RR, 0.84; 95% CI: 0.44-1.61; P = 0.60 respectively). Severe adverse events were significantly less in endoscopic variceal ligation compared with beta-blockers (RR, 0.34; 95% CI: 0.17-0.69; P = 0.0024; NNTB = 28). Sensitivity analysis of five trials published in peer review journals and four trials with high quality showed results similar to those seen in the primary analysis of all the eight trials, confirming stability of conclusions. Following variceal obliteration with endoscopic variceal ligation, oesophageal varices recurred in 83 (29.1%) patients. Seven (28.1%) patients bled with one fatal outcome. In subgroup analyses, endoscopic variceal ligation had significant advantage compared wtih beta-blockers in trials including < or =30% patients with alcoholic cirrhosis, >30% patients with Child Class C cirrhosis and >50% patients with large varices. CONCLUSIONS: In patients with cirrhosis with moderate to large varices and who have not bled, endoscopic varices ligation compared with beta-blockers significantly reduced bleeding episodes and severe adverse events, but had no effect on mortality.

A carbocyclic nucleoside analogue is a TNF-alpha inhibitor with immunosuppressive action: role of prostaglandin E2 and protein kinase C and comparison with pentoxifylline.

Tumor necrosis factor-alpha (TNF-alpha) is associated with several acute and chronic inflammatory conditions. New therapies directed at inhibiting TNF-alpha will be important in treating pathological processes mediated by TNF-alpha. In this study, we studied and compared the effect of the carbocyclic nucleoside analogue (9-[(1R, 3R)-trans-cyclopentan-3-ol] adenine) with pentoxifylline on modulating TNF-alpha production. The carbocyclic nucleoside analogue inhibited TNF-alpha production in a dose-dependent manner (1 microM-1 mM) by stimulated peripheral blood mononuclear cells and cell lines of both monocyte (THP-1) and T-lymphocyte phenotypes (CEM x 174). The drug potently inhibited TNF production in cells stimulated by endotoxin, the superantigen (staphylococci enterotoxin A), the mitogen (phytohemagglutinin), and the protein kinase C activator (phorbol myristate acetate) with ED50 ranging from 5 to 30 microM. At moderate concentrations, the carbocyclic nucleoside analogue inhibited superantigen (ED50 = 300 microM) and alloantigen (mixed lymphocyte reaction) T cell proliferative responses (ED50 = 150 microM). The involvement of protein kinase C and prostaglandin E2 (PGE2), mediators that regulate TNF-alpha production, was also investigated. Unlike PTX, the nucleoside analogue did not upregulate PGE2 production. The inhibition of TNF-alpha production appeared to be mediated at least partly by PKC, since the nucleoside analogue caused suppression of PKC activity in stimulated cells. The results show that the carbocyclic nucleoside analogue is a TNF-alpha inhibitor that may be appropriate in the therapy of TNF-alpha-associated complications. The suppressive properties of the carbocyclic nucleoside analogue on antigen and alloantigen (mixed lymphocyte reaction) responses may be appropriate in disease conditions in which inhibiting both TNF-alpha and T-cell reactivity is desirable.