Double Strength Research Articles

P-2298. Daily Single-strength vs. Thrice-weekly Double-strength Trimethoprim/sulfamethoxazole for Pneumocystis jirovecii Prophylaxis in Kidney Transplant Recipients: A Non-inferiority Randomized Controlled trial

Abstract Background Pneumocystis jirovecii pneumonia (PCP) is commonly encountered among kidney transplant (KT) recipients. Either daily or thrice-weekly, single strength (SS) or double strength (DS) trimethoprim/sulfamethoxazole (TMP/SMX) is recommended after KT to prevent PCP. However, a direct comparison between these regimens in terms of PCP prevention is lacking. We assessed the efficacy of SS daily (DSS) versus DS thrice weekly (TDS) TMP/SMX prophylaxis for PCP within the first 6 months post-transplant in KT recipients. Methods We conducted a single-center block of 4 randomized, open-label, non-inferiority, randomized controlled trial at a single transplant center between December 2022 and December 2023. All KT recipients 15 years and older were included. The single-strength group received TMP/SMX 80/400 mg daily after KT, while the double-strength group received two tablets of SS doses thrice weekly. PCP occurrence was observed for 6 months, and side effects of TMP/SMX and ease of drug consumption were monitored. Results A total of 65 KT recipients were included. The participants had a mean age (SD) of 46 (11) years old, with the following proportion: male gender (58%), deceased donor KT (20%), anti-thymocyte globulin as induction therapy (17%), and CMV seropositivity (95%). There were 32 and 33 KT recipients assigned to the DSS and TDS groups, respectively. Baseline characteristics between the two groups were comparable. At 6 months after transplant, all patients remained free from PCP in both groups. There was a non-significant lower mean (SD) of white blood cell counts in the DSS group compared to the TDS group [6,235 (2,271) vs.7,052 (2,464) cells/mm3, p = 0.23], respectively. In parallel, there was no significant difference in terms of hepatotoxicity or renal dysfunction among those groups. According to per-protocol analysis, 27 (96%) of the DSS group reported having convenient administration of the drug compared to 18 (100%) of the TDS group (p = 0.60). Conclusion TMP/SMX appears to efficiently prevent PCP in the early period after KT. Both SS daily and DS thrice-weekly regimens seem to be comparable in terms of effectiveness, tolerability, and compliance. Further studies with larger samples are encouraged to support this result. TCTR20240329004. Disclosures All Authors: No reported disclosures

Sequential γ-ε-α′ transformation preserves high elongation in an ultrafine-grained high Mn steel

While grain refinement is a prominent way to improve the yield strength of metastable austenitic steels, it usually leads to a reduction in the uniform elongation as γ-α′ transformation tends to be suppressed. In the current study, it is found that the sequential γ-ε-α′ transformation helps an ultrafine-grained high Mn austenitic steel maintain high uniform elongation while having more than doubled yield strength compared to the coarse-grained counterpart. Although the grain refinement is unfavorable for the γ-ε transformation due to ε variant selection within the refined γ grains, the ε-α′ transformation is not affected as multiple α′ variants can form within one ε grain. The combination of a higher α′ transformation rate and delayed transformation kinetics enables continued strain hardening, leading to high uniform elongation.

Mechanical performance of coal ash based interlocking bricks wall panel: A sustainable and viable solution

The use of interlocking brick incorporating waste coal ash (CA) in masonry construction is an innovative, sustainable and viable solution to address the consequences associated with burnt clay bricks. In this research, the main focus was to study the double interlocking brick incorporating CA for its potential use in masonry construction. The studied dosages of CA were 30 %, 35 %, 40 %, 45 %, 50 % and 55 %. Cement was varied between 5 % and 30 % in order to make the total binder (cement and CA) contents equal to 60 %. Moreover, wall panels using developed interlocking bricks were casted and tested for out-of-plane loading. It was observed that the incorporation of higher dosage of CA decreased the compressive strength owing to porous nature of used CA. However, interlocking bricks having 30 % of CA exhibited compressive strength higher than 8 MPa, satisfying the local building code requirement. Higher water absorption was observed for interlocking bricks having higher dosage of CA compared to identical bricks with lower CA. Interlocking bricks exhibited higher shear strength due to mechanical anchorage provided by the keys and notches in comparison with the conventional bricks. Maximum double key shear strength of 2.34 MPa was observed for developed interlock bricks incorporating 30 % of CA. Interlocking brick wall panel exhibited flexural strength of 1.05 MPa compared to 0.81 MPa for wall panel constructed using conventional burnt clay brick. Higher flexural strength of interlock CA based brick wall panel was due to the higher mechanical anchorage provided by the projected keys and grooves in between various courses of the wall panel. The cracking patterns of interlocking brick wall panel exhibited diagonal failure rather than the horizontal slide shear failure observed for conventional burnt clay brick wall panel. The experimental cracking load values were comparable with the theoretically predicted cracking loads for the tested wall panels. This study highlights the use of water cured interlocking brick incorporating waste CA for eco-friendly and economical construction leading to avoid the devasting effects of manufacturing process of conventional burnt clay bricks and deposition issues of CA. Moreover, this study motivates the construction stakeholders to employ double interlocking bricks of similar conventional size bricks to be used in a similar manner for masonry construction.

Direct activation of PI3K in osteoblasts and osteocytes strengthens murine bone through sex-specific actions on cortical surfaces.

Intracellular phosphoinositide 3-kinase (PI3K) signaling is activated by multiple bone-active receptors. Genetic mutations activating PI3K signaling are associated with clinical syndromes of tissue overgrowth in multiple organs, often including the skeleton. While one formation is increased by removing the PI3K inhibitor (phosphatase and TENsin homolog deleted on chromosome 10 (PTEN)), the effect of direct PI3K activation in the osteoblast lineage has not been reported. We introduced a known gain-of-function mutation in Pik3ca, the gene encoding the p110α catalytic subunit of PI3K, in osteocytes and late osteoblasts using the dentin matrix protein-1 Cre (Dmp1Cre) mouse and assessed the skeletal phenotype. Femur shape was grossly normal, but cortical thickness was significantly greater in both male and female Dmp1Cre.Pik3caH1047R mice, leading to almost doubled bone strength at 12wk of age. Both sexes had smaller marrow areas from 6wk of age. Female mice also exhibited greater cross-sectional area, which continued to increase until 24wk of age, resulting in a further increase in bone strength. Although both male and female mice had increased endocortical mineralizing surface, only female mice had increased periosteal mineralizing surface. The bone formed in the Dmp1Cre.Pik3caH1047R mice showed no increase in intracortical remodeling nor any defect in cortical bone consolidation. In contrast, on both endocortical and periosteal surfaces, there was more lamellar bone formation, including highly organized osteocyte networks extending along the entire surface at a greater thickness than in control mice. In conclusion, direct activation of PI3Kα in cells targeted by Dmp1Cre leads to high cortical bone mass and strength with abundant lamellar cortical bone in female and male mice with no increase in intracortical remodeling. This differs from the effect of PTEN deletion in the same cells, suggesting that activating PI3Kα in osteoblasts and osteocytes may be a more suitable target to promote formation of lamellar bone.

Double Strength Reduction Method for Carbonaceous Rock Slope Considering Influence of Disintegration Degree

Double Strength Reduction Method for Carbonaceous Rock Slope Considering Influence of Disintegration Degree

Achieving excellent strength-ductility-superelasticity combination in high-porosity NiTiNb scaffolds via high-temperature annealing

Metallic scaffolds with lightweight, low elastic modulus, and high energy-absorbing capacity are widely utilized in industrial applications but usually require post-heat treatment to enhance their comprehensive mechanical properties. However, it is unclear how to utilize the impact of β-Nb on the surrounding matrix for NiTiNb ternary alloys to achieve strength-ductility-superelasticity enhancement. Here, we prepared rhomboidal dodecahedral NiTiNb porous scaffolds with a porosity of 85.9% by additive manufacturing. Subsequently, annealing treatment was employed to drastically reduce the phase transformation temperatures and expand the thermal hysteresis. Interestingly, the 850 °C annealed scaffold exhibited exceeding double compressive strength of the as-built sample, with a remarkable improvement in ductility and superelasticity. From the microstructure perspective, high-temperature annealing caused a further eutectic reaction of the unmelted Nb particles with the NiTi matrix and the transformation of mesh-like β-Nb into dispersedly distributed spherical β-Nb particles. The microstructure evolution after deformation indicated that stress-induced martensitic transformation occurred in the matrix away from the NiTi-Nb eutectic region whereas almost no martensite formed nearby β-Nb particles. Atom probe tomography characterization revealed an element diffusion zone in several nanometers surrounding the β-Nb particle, where the substitution of Nb with Ti led to a higher Ni: Ti atomic ratio, lowering transformation temperatures. Molecular dynamics simulations illustrated that β-Nb particles can not only entangle dislocations internally, acting as reinforcements but also hinder the twin growth, contributing to strain hardening. This work elucidates the influence of β-Nb particles on the deformation mechanism of the NiTi-Nb eutectic region through in-depth atomic-scale investigation, which can provide inspiration for the improvement of comprehensive mechanical properties of NiTiNb alloys.

Biological and computational assessment of new synthesized nicotinamides as potential immunomodulatory VEGFR-2 inhibitors

As an extension to our preceding studies on nicotinamide derivatives as anticancer agents, new nicotinamide-based candidates were designed and synthesized as VEGFR-2 inhibitors. The in vitro cytotoxic activity of the synthesized compounds was evaluated against three human cancer cell lines (MCF-7, HepG-2 and HCT-116). The IC50 values for compound 17 were 2.61± 0.01, 3.20 ± 0.02, and 2.46 ± 0.01 µM, respectively, compared to sorafenib (4.21±0.03, 3.40 ± 0.02, and 5.30 ± 0.04 µM) against MCF-7, HePG-2, and HCT-116. This indicated that compound 17 possess double strength relative to sorafenib against both MCF-7 and HCT-116. Compound 17 was the most promising VEGFR-2 inhibitor with IC50 value of 0.34 μM that was slightly better than that of sorafenib (0.38 μM). Further studies displayed the ability of compound 17 to arrest the growth of HCT-116 cells at the Pre-G1 and S phases. Additionally, compound 17 induced a significant increase in the total apoptosis rate of HCT-116 cells from 1.82 % to 26.69 %. Moreover, it showed high selectivity indices against HCT-116, HepG2, and MCF-7 cancer cells. Furthermore, compound 17 showed potent inhibitory activities on TNF-α and IL-6 and showed a notable rise in caspase-3 level. In addition, the potentiality of the designed derivatives to bind with and inhibit the VEGFR-2 enzyme was indicated by molecular docking assessments. MD simulation studies revealed the stability of compound 17 in the active site of VEGFR-2 for 100 ns. Based on the previous findings, compound 17 appears to be a promising apoptotic VEGFR-2 inhibitor and could potentially direct future efforts towards the development of novel anticancer medications.

Grain alignment in hexaferrite permanent magnets by compaction at room and elevated temperatures.

Shape-controlled precursors enable grain alignment without using an applied magnetic field in the permanent magnet material strontium hexaferrite. The effect is investigated by conducting four series of experiments using different compaction methods: two cold and two hot compactions. The hypothesis is that magnetic short-circuiting will diminish the grain alignment (texture) in cold compacted samples. The two cold compactions were performed below the Curie temperature, one being a simple cold-pressing (CP) and the other being a cold-pressing followed by sintering (CPS). The CP samples showed a relatively weak texture and low remanent magnetisation, while the CPS method yielded a slightly sharpened texture and improved remanent magnetisation compared with CP. In the two hot compactions, the pressing was done above the Curie temperature, using spark plasma sintering (SPS) and induction pressing (IP). SPS and IP samples both showed remarkably sharper textures than the cold-pressed pellets, with roughly doubled texture strength, and consequently better remanent magnetisation. The bulk density of the hot compacted samples increased almost twofold compared with that of the cold compactions. Hot compaction outperforms cold compaction with regard to density, sharpness of texture and remanent magnetisation. This is explained by inter-particle magnetic short-circuiting during cold pressing, which hinders the alignment process and reduces the bulk density.

Сравнительное исследование двойного и сдвоенного электроиндукционных сферических датчиков напряженности электрического поля

The work provides a comparative study of double and dual electric field strength sensors. The comparison examined the design, technological and metrological parameters of the sensors, as well as the complexity of their measuring circuits. Research has revealed similarities in the design and technological parameters of the sensors and differences in metrological characteristics and the complexity of the measuring circuits. In terms of metrological characteristics, dual sensors are significantly superior to double ones. It has been established that a dual sensor having sensitive elements with angular dimensions 1=46,38 , and 2=90 , has a smaller error due to field inhomogeneity. The error does not exceed  ±2,76 % in the spatial measurement range 0a1. With the same error, double sensors can only be used in a limited spatial measurement range of 0a0,89. It is shown that dual sensors are superior to dual sensors in terms of metrological parameters. This indicates the advisability of their use.

Mechanical and clogging characteristics of SBR modified pervious concrete reinforced with geogrids - A Functional Data Analysis approach

Pervious concrete is a special type of concrete with high porosity but with limited structural strength. Geogrid reinforced pervious concrete is a specialized type of pervious concrete that incorporates geogrids for added structural performance. The composite material benefits from the geogrid's tensile strength and load-spreading capability with the addition of geogrids. Present study aims at investigating the mechanical, shrinkage and clogging characteristics of Styrene Butadiene Rubber (SBR) modified pervious concrete reinforced with glass fiber mesh, HDPE mesh, fiber glass geogrid, HDPE geogrid and coir geogrid. SBR modification is done from 0% to 15% by weight of cement The results show a palpable improvement in flexural strength of pervious concrete. HDPE geogrid provides almost the double flexural strength as non-reinforced pervious concrete. SBR modification of pervious concrete also enhanced the mechanical properties. Each grid/mesh has its own optimum dosage of SBR for maximum flexural strength. Laying geogrids can reduce the drying shrinkage of pervious concrete. The relative contact area of grid/mesh with the cement paste is a critical factor in reducing drying shrinkage. However, geogrid can lead to clogging in pervious concrete. Soil particles get accumulated in the void spaces and thereby reduce its permeability. Coir geogrid traps a larger quantity of soil particles impairing the permeability. Functional regression modelling by Functional Data Analysis approach is used to analyse the relationship between various grids and meshes with the properties of pervious concrete. The p-value and derivative plots gives better insight into the factorial effects.

A Calculation Method of Double Strength Reduction for Layered Slope Based on the Reduction of Water Content Intensity

A Calculation Method of Double Strength Reduction for Layered Slope Based on the Reduction of Water Content Intensity

Machine learning based graphical interface for accurate estimation of FRP-concrete bond strength under diverse exposure conditions

Predicting FRP-to-concrete bond strength (FRP-CBS) under diverse exposure conditions is an intricate task influenced by multiple variables. Yet, existing pertinent models have several limitations. Accordingly, this study proposes a novel data driven machine learning (ML) methodology to predict the FRP-CBS considering various exposure conditions. A comprehensive database on single and double lap-shear strength tests on concrete specimens was meticulously compiled. Twenty-seven analytical models were used to appraise the developed ML models. Feature importance analysis was conducted to ascertain the influence of input parameters on bond strength. The proposed data-driven ML models attained exceptional accuracy and superior performance compared to existing analytical models. To enhance the accuracy of bond strength estimation and simplify the process for practicing engineers and FRP applicators, a user-friendly graphical interface was developed. It could eliminate the need for complex design procedures, making it easier to accurately estimate the FRP-CBS, thus improving overall efficiency in engineering practice.

Stabilisation of estuarine sediments with an alkali-activated cement for deep soil mixing applications

In this work, an alternative alkali-activated cement (AAC) made of ladle slag precursor mixed with sodium hydroxide and sodium silicate has been developed to enhance the bearing capacity of estuarine soils in coastal conditions via deep soil mixing (DSM). The AAC was optimized to use a low reactivity precursor (ladle slag) and to deal with a contaminated high-water content natural sediment cured under water. The material performance was analysed by comparison to a mixture made with Portland cement and cured in the same conditions. Flexural and unconfined compressive strength tests as well as seismic waves measurements after 3-, 7-, 14- and 28-d curing were performed to obtain a relationship between elastic stiffness and strength with curing time for both mixtures. Remarkably, the AAC mix demonstrated superior strength results, exhibiting almost double flexural and compressive strengths after 28 d compared to the Portland cement mix. The AAC mix also showed a higher rate of stiffness increase than the Portland cement mix, which has a higher initial stiffness at young ages but lower stiffness evolution. Leachate analysis confirmed that the proposed AAC could effectively immobilise any contaminants from soil or precursors. The effect of curing under stress was analysed in triaxial compression tests and found to be insignificant, indicating that laboratory data obtained without stress curing can represent the material's behaviour in a DSM column, which will cure under the weight of the column.

Realizing reversible phase transformation of shape memory ceramics constrained in aluminum

Small-scale shape memory ceramics exhibit superior shape memory or superelasticity properties, while their integration into a matrix material and the subsequent attainment of their reversible tetragonal-monoclinic phase transformations remains a challenge. Here, cerium-doped zirconia (CZ) reinforced aluminum (Al) matrix composite is fabricated, and both macroscopic and microscopic mechanical tests reveal more than doubled compressive strength and energy absorbance of the composites as compared with pure Al. Full austenitization in the CZ single-crystal clusters is achieved when they are constrained by the Al matrix, and reversible martensitic transformation triggered by thermal or stress stimuli is observed in the composite micro-pillars without causing fracture in the composite. These results are interpreted by the strong geometric confinement offered by the Al matrix, the robust CZ/Al interface and the local three-dimensional particle network/force-chain configuration that effectively transfer mechanical loads, and the decent flowability of the matrix that accommodates the volume change during phase transformation.

Significant improvement of mechanical properties of cold-spray-additive manufactured FeCoNiCrMn high-entropy alloy via post-annealing

In this work, equimolar FeCoNiCrMn high-entropy alloy (HEA) was fabricated by solid-state cold spray additive manufacturing (CSAM) technique and post-annealed. The microstructure evolution and mechanical properties of the deposits before and after annealing were systematically evaluated. The tensile test results revealed that the deposit annealed at 1000 °C for 2 h exhibited an excellent combination of tensile strength and ductility, with a doubled ultimate tensile strength of 455 MPa compared with the as-sprayed and significantly improved elongation (28%). The improved strength can be attributed to the healing of micropores and interparticle interfaces in the deposit due to the interface diffusion induced by high temperature. The recovery of ductility is the result of a significantly decreased dislocation density and enhanced metallurgical bonding at interfacial regions. For the first time, the current work demonstrated that the combination of CSAM and post-annealing strategy could achieve the strength-ductility synergy of HEA deposits. The results of in-situ analysis show that the mechanism of tensile deformation process includes particle separation, and it can be inferred that the preparation of dense sediments combined with post-treatment is the direction of further optimization.

Microband-driven martensitic transformation in as-hot-rolled metastable medium-entropy alloys

Hot rolling triggers dynamic recrystallization and dislocation-based microbands. Dislocations within these microbands in as-hot-rolled metastable medium-entropy alloys prompt deformation-induced martensitic transformation at ambient temperature, a phenomenon not identifiable in the as-annealed counterparts. This results in ∼43% total elongation despite the as-rolled states with the added benefit of doubled yield strength.

Efficient Photopolymerization of Dental Resin Composites Using the Photoluminescent Long Afterglow of Sr2MgSi2O7:Eu2+,Dy3.

Dental curing light with blue emission acts as the excitation source for the photopolymerization of the dental composite resin to achieve dental repairing. However, the current repair methods still suffer from a low monomer conversion degree and incomplete resin curing. In this study, novel dental resin composites (DRCs) were prepared by combining Sr2MgSi2O7:Eu2+,Dy3+ (SMSED), a photoluminescent material with a blue long afterglow, and dental resin composites. The curing depth, double bond conversion, elastic modulus, compressive strength, water absorption and solubility, and cytotoxicity were investigated systematically. The results suggest that adding 1 wt % SMSED to dental resin composites can maximize the curing depth and double bond conversion rate of DRCs and reduce its water absorption capacity without affecting the mechanical properties and biological toxicity. This work explores the practical applications of SMSED in dental resin composites, which provides an important reference for further improving the effect of dental caries repair.

Three-dimensional stability analysis of tunnel face based on unified strength theory

The impact of cyclic footage and intermediate principal stress on the stability of the tunnel-face area are analyzed in this study using the theory of limit analysis. The study introduces the unified strength theory and proposes three-dimensional logarithmic spiral failure modes with corresponding velocity fields. The influence of various parameters on the tunnel-face area stability is analyzed, and it is found that when the internal friction angle is less than 30°, the internal friction angle parameters should be improved first to enhance stability, while when the internal friction angle is greater than 30°, cohesion should be prioritized. When using the double shear uniform strength theory in the tunnel-face area, the intermediate principal stress can improve the stability of the tunnel face. Results show that Mohr–Coulomb criterion calculations are conservative in the good surrounding ground, but no similar conclusion has been obtained for the poor surrounding ground, and specific problems must be analyzed during construction.

Effect of double spin-orbit parameters of spin-orbit strength in reactions involving spherical-prolate, spherical-oblate, oblate-prolate and oblate-oblate configurations

The present work is carried out to see the role of double spin-orbit parameters (W1 and W2) on reactions having spherical-prolate, spherical-oblate, oblate-prolate and oblate-oblate configurations. For the study, semi-classical Skyrme energy density formalism is used by employing SkIx (x=2,3,4) and SAMi Skyrme forces. The calculations suggest that the presence of double spin-orbit strength imparts significant influence on spin-dependent potential (VJ) as maximum barrier height of VJ (VJB) is observed with SAMi force (W1≠W2) and minimum with SkI2 (W1=W2) i.e., VJB(SAMi)>VJB(SkI4)>VJB(SkI3)>VJB(SkI2). The maxima and minima in VJB are further related to the contribution from the isoscalar and isovector parts of the spin-orbit potential. As far as shape of projectile and(or) target is concerned, the higher VJB is obtained for oblate-prolate configuration and lower when spherical-prolate configuration is used. The chosen Skyrme forces also modify the fusion barrier height VB of different target-projectile combinations in the similar way as the spin-orbit barrier height (VJB) does. These Skyrme forces are further applied to address the experimental fusion excitation functions and fusion barrier distributions of the considered reacting partners. The contribution of VJ is also estimated in fusion cross-section of considered reactions.

High-Performance Castor Oil-Based Polyurethane Composites Reinforced by Birch Wood Fibers

A new method for the preparation of coatings based on renewable biomaterials such as castor oil and birch flour is suggested in this study. The introduction of birch flour in a polyurethane matrix synthesized from castor oil and oligomeric methylene diphenyl diisocyanate (MDI) leads to a more than doubled value of tensile strength and almost doubled strength of adhesion to steel at 20 wt.% loading. The composite with such level loading has tensile strength equal to 7.1 MPa at an elongation at break of 31%, with an adhesion to steel of 3.71 MPa. Hence, the use of such level loading allows for an increase in tensile strength of 887.5% in comparison with that of polyurethane based on neat (as received) castor oil, leading to a decrease in the value of elongation at break. The adhesion to steel of these composites increases by 185.5% in comparison with starting polyurethane. FTIR and SEM studies identified the mechanism of the reinforcement effect of birch fibers. This reinforcement is based on the good wetting of birch fibers by polyurethane with the formation of chemical bonds between them, and the cellulose and lignin components of wood fillers. As a result, we obtained cheap bio-based coatings with acceptable mechanical and adhesion properties.