Perspective/Discussion on “Quantum Mechanical Metric for Internal Cohesion in Cement Crystals” by C. C. Dharmawardhana, A. Misra and Wai-Yim Ching

The single most important structural material, and the major Portland cement binding phase in application globally, is calcium silicate hydrate (C-S-H). The concentration has increasingly changed due to its atomic level comprehension because of the chemistry and complex structures of internal C-S-H cohesion in cement crystals at different lengths. This perspective aimed at describing on calcium-silicate-hydrates (C-S-H) structures with differing contents of Ca/Si ratio based on the report entitled “Quantum mechanical metric for internal cohesion in cement crystals” published by C. C. Dharmawardhana, A. Misra and Wai-Yim Ching. Crystal structural and bond behaviors in synthesized C-S-H were also discussed. The investigator studied large subset electronic structures and bonding of the common C-S-H minerals. From each bonding type, the results and findings show a wide variety of contributions, particularly hydrogen bonding, that allow critical analyses of spectroscopic measurement and constructions of practical C-S-H models. The investigator found that the perfect overall measurement for examining crystal cohesions of the complex substances is the total bond density (TBOD), which needs to be substituted for traditional metrics such as calcium to silicon ratios. In comparison to Tobermorite and Jennite, hardly known orthorhombic phased Suolunites were revealed to have greater cohesion and total order distribution density than those of the hydrated Portland cement backbone. The findings of the perspective showed that utilizing quantum mechanical metrics, the total bond orders and total bond order distributions are the most vital criteria for assessing the crystalline cohesions in C-S-H crystals. These metrics encompass effects of both interatomic interactions and geometric elements. Thus, the total bond order distribution and bond order offer comprehensive and in-depth measures for the overall behaviors of these diverse groups of substances. The total bond order distributions must clearly be substituted for the conventional and longstanding Ca/Si ratios applied in categorizing the cement substances. The inconspicuous Suolunite crystals were found to have the greatest total bond order distributions and the perfect bonding characteristics, compositions, and structures for cement hydrates.

The Effects of Sinter-Hip Processing on the Machining Performance of Cemented Carbides Based on NBC-NI Systems as Alternative Cutting Tools

This work aims to investigate the technical feasibility of using sintered carbides based on NbC-Ni substitute of the WC-Co class, adding the Sinter-Hip step in the sintering process, with 20 bar pressure nitrogen gas. The samples were produced investigating two process variables: sintering cycles and chemical composition. The samples were qualified in terms of Vickers hardness, toughness and density by Archimedes. The machining experiments were carried out on quenched and tempered AISI 4340 steel material. Flank wear progression was defined as the control parameter, analyzing wear via CCD camera, stereoscopic magnifying glass and SEM/EDS. The best result obtained the binding phase content 10%w, when compared to a commercial WC-Co insert. It showed superior performance at 88% of the average life of the cutting edge. However, the dispersion of this lifetime was higher than the WC-Co reference tool, 15%. The samples of NbC-10%p Ni showed a higher level of porosity than WC-Co. For better densification, new samples with the same composition were produced by adding the Sinter-HIP step. New tests were carried out and the results showed that the adjustment of the sintering process was fundamental. Densification and microstructure alteration reduced the dispersion of the average lifetime of this new NbC-Ni class.

Structure, Fractality, Mechanics and Durability of Calcium Silicate Hydrates

Cement-based materials are widely utilized in infrastructure. The main product of hydrated products of cement-based materials is calcium silicate hydrate (C-S-H) gels that are considered as the binding phase of cement paste. C-S-H gels in Portland cement paste account for 60–70% of hydrated products by volume, which has profound influence on the mechanical properties and durability of cement-based materials. The preparation method of C-S-H gels has been well documented, but the quality of the prepared C-S-H affects experimental results; therefore, this review studies the preparation method of C-S-H under different conditions and materials. The progress related to C-S-H microstructure is explored from the theoretical and computational point of view. The fractality of C-S-H is discussed. An evaluation of the mechanical properties of C-S-H has also been included in this review. Finally, there is a discussion of the durability of C-S-H, with special reference to the carbonization and chloride/sulfate attacks.

Decoding the physical principles of two-component biomolecular phase separation

Cells possess a multiplicity of non-membrane-bound compartments, which form via liquid-liquid phase separation. These condensates assemble and dissolve as needed to enable central cellular functions. One important class of condensates is those composed of two associating polymer species that form one-to-one specific bonds. What are the physical principles that underlie phase separation in such systems? To address this question, we employed coarse-grained molecular dynamics simulations to examine how the phase boundaries depend on polymer valence, stoichiometry, and binding strength. We discovered a striking phenomenon – for sufficiently strong binding, phase separation is suppressed at rational polymer stoichiometries, which we termed the magic-ratio effect. We further developed an analytical dimer-gel theory that confirmed the magic-ratio effect and disentangled the individual roles of polymer properties in shaping the phase diagram. Our work provides new insights into the factors controlling the phase diagrams of biomolecular condensates, with implications for natural and synthetic systems.

The Influence of Anti-Hiv-1 Specific IgY In Inhibiting HIV-1 Infection in Binding Phase with Syncytium Examination of CD4 Receptor Density Using the Flowcytometry Method

HIV/ AIDS infections have increased and spread very quickly in the world, including in Indonesia. The absence of an effective vaccine and the fact that antiretroviral drugs can only suppress the progression of infection but cannot eradicate it lead to the efforts to find materials containing immunoglobulins that can replace the immune system which greatly declines in HIV/ AIDS patients. The successful use of specific IgY in other studies opens up opportunities for the use of anti-HIV-1 specific IgY as passive immunotherapy. This type of research is true experimental research design with post-test only control group design. IgY was obtained from Lohmann Laying hens chicken eggs immunized with the inactivated HIV-1 virus. The concentration of IgY was determined using the Bradford method and then the characterization test was continued using the AGPT, ELISA, SDS-PAGE and Western blot tests which showed anti-HIV-1 specific IgY. The results of the test showed specific anti-HIV-1 IgY was effective in inhibiting the formation of syncytium in HIV-1 infection against CD4+ T lymphocytes in the binding phase (entry stage) in the treatment group p-value 0.000 (p <0.05). The results of CD4 receptor density tests using the Flowcytometry method showed that specific anti-HIV-1 IgY was effective in inhibiting HIV-1 infection against CD4+ T lymphocytes in the binding phase (entry stage) in the treatment group p-value 0.047 (p <0.05).HIV/ AIDS infections have increased and spread very quickly in the world, including in Indonesia. The absence of an effective vaccine and the fact that antiretroviral drugs can only suppress the progression of infection but cannot eradicate it lead to the efforts to find materials containing immunoglobulins that can replace the immune system which greatly declines in HIV/ AIDS patients. The successful use of specific IgY in other studies opens up opportunities for the use of anti-HIV-1 specific IgY as passive immunotherapy. This type of research is true experimental research design with post-test only control group design. IgY was obtained from Lohmann Laying hens chicken eggs immunized with the inactivated HIV-1 virus. The concentration of IgY was determined using the Bradford method and then the characterization test was continued using the AGPT, ELISA, SDS-PAGE and Western blot tests which showed anti-HIV-1 specific IgY. The results of the test showed specific anti-HIV-1 IgY was effective in inhibiting the formation of syncytium in HIV-1 infection against CD4+ T lymphocytes in the binding phase (entry stage) in the treatment group p-value 0.000 (p <0.05). The results of CD4 receptor density tests using the Flowcytometry method showed that specific anti-HIV-1 IgY was effective in inhibiting HIV-1 infection against CD4+ T lymphocytes in the binding phase (entry stage) in the treatment group p-value 0.047 (p <0.05).

The Influence of Anti-Hiv-1 Specific IgY In Inhibiting HIV-1 Infection in Binding Phase with Syncytium Examination of CD4 Receptor Density Using the Flowcytometry Method

HIV/AIDS infections have increased and spread very quickly in the world, including in Indonesia. The absence of an effective vaccine and the fact that antiretroviral drugs can only suppress the progression of infection but cannot eradicate it lead to the efforts to find materials containing immunoglobulins that can replace the immune system which greatly declines in HIV/ AIDS patients. The successful use of specific IgY in other studies opens up opportunities for the use of anti-HIV-1 specific IgY as passive immunotherapy. This type of research is true experimental research design with post-test only control group design. IgY was obtained from Lohmann Laying hens chicken eggs immunized with the inactivated HIV-1 virus. The concentration of IgY was determined using the Bradford method and then the characterization test was continued using the AGPT, ELISA, SDS-PAGE and Western blot tests which showed anti-HIV-1 specific IgY. The results of the test showed specific anti-HIV-1 IgY was effective in inhibiting the formation of syncytium in HIV-1 infection against CD4+ T lymphocytes in the binding phase (entry stage) in the treatment group p-value 0.000 (p <0.05). The results of CD4 receptor density tests using the Flowcytometry method showed that specific anti-HIV-1 IgY was effective in inhibiting HIV-1 infection against CD4+ T lymphocytes in the binding phase (entry stage) in the treatment group p-value 0.047 (p<0.05).

A QM/MM Investigation of the Catalytic Mechanism of Acetylene Hydratase: Insights into Engineering a More Effective Enzyme

In the present investigation, a QM/MM approach was used to better understand the effect of the second environmental shell of the active site on the catalytic conversion of acetylene to acetaldehyde by acetylene hydratase (AH). In addition, the effect of substituting W-coordinating sulfur atoms with selenium atoms was done to provide insight into the influence of the W-coordinating atoms on the catalytic reaction. From the results, it found that the presence of the second shell environment had a significant effect on the reaction. Specifically, in the absence of the MM second shell environment(i.e., QM-cluster model), the reaction rate-determining step is defined by the first proton transfer step. In contrast, for the QM/MM model, the rate-determining step is defined by the water attacking step. Moreover, with the presence of the MM second shell environment, a key intermediate found in the DFT-cluster investigation does not exist in the QM/MM investigation. Rather, what was a two-step process in the DFT-cluster study was calculated to occur in a single step for the QM/MM study. Regarding the sulfur to selenium substitutions, it was found that Gibbs energy for the acetylene binding phase was significantly affected. Notably, the trans-position selenium made the binding of acetylene 65.6 kJ mol-1 less endergonic. Moreover, the overall reaction became 38.2 kJ mol-1 less endergonic compared to the wild type (WT) AH model. Thus, the substitution of key W-coordinating sulfur atoms with selenium atoms may offer a means to enhance the catalytic mechanism of AH considerably.

Some data on the TiC-TiNi system's hard-alloy composite with high performance properties

The data are provided on the composite material of the TiC-TiNi system with increased performance properties, which belong to the group of CM based on refractory titanium compounds called "tungsten-free hard alloys". The concept of a structural-energy transition from the perspective of thermodynamics is involved and developed. Based on this concept, the evolution of the structural-energy state of a composite material in the form of a model with two energy levels is considered. In the process of forming a composite mixture with a stable equilibrium structure, new stress-strain structures with an energy level of E1, which are unstable and have higher mechanical properties, arise. During sintering, the deformed structures with the energy level E1 pass into a more stable state with the energy level E2 due to the formation of energy-winning eutectic structures of the TiNi binding phase and the fine-grained dense structure of TiC carbides, which represent a steady metastable structure of the composite. It is established that depending on the volume concentration of the TiNi binding phase, the development of thermodynamic processes for forming the structure of a hard-alloy composite leads to the production of a final structure of the two different types and performance properties. It is shown that the critical concentration can be considered a volume concentration of 40% (vol). The resonant-acoustic method allowed to determine the visco-elastic characteristics (Young, shear, and compression moduli; Poisson's ratio), as well as their dependence on the concentration of the binding phase. The Young's modulus is theoretically calculated. It was found that the use of TiC-TiNi hard-alloy composite allows to increase the efficiency of the cutting tool and technological equipment by one and a half times compared to a tool made of the known tungsten-free alloys KNT-16, TN-(20, 30) and KTS.