Effect Of Treatment Research Articles

Non-proportional hazards model with a PVF frailty term: application with a melanoma dataset

Survival data analysis often uses the Cox proportional hazards (PH) model. This model is widely applied due to its straightforward interpretation of the hazard ratio under the assumption that the hazard rates for two subjects remain constant over time. However, in several randomized clinical trials with long-term survival data comparing two new treatments, it is frequently observed that Kaplan-Meier plots exhibit crossing survival curves. This violation of the PH assumption of the Cox PH model can not be applied to evaluate the treatment's effect on survival. This paper introduces a novel long-term survival model with non-PH that incorporates a frailty term into the hazard function. This model allows us to examine the effect of prognostic factors on survival and quantify the degree of unobservable heterogeneity. The model parameters are estimated using the maximum likelihood estimation procedure, and we evaluate the performance of the proposed models through simulation studies. Additionally, we demonstrate the applicability of our approach by fitting the models to a real skin cancer dataset.

Effect of dapagliflozin in patients with diabetes and heart failure with mildly reduced or preserved ejection fraction according to background glucose-lowering therapy: A pre-specified analysis of the DELIVER trial.

Type 2 diabetes (T2D) and heart failure (HF) frequently coexist, but whether clinical outcomes and treatment effects of sodium-glucose cotransporter 2 inhibitors (SGLT2i) vary in relation to background glucose-lowering therapy (GLT) in this population is uncertain. DELIVER randomized patients with HF and left ventricular ejection fraction (LVEF) >40% to dapagliflozin or placebo. The primary outcome was a composite of worsening HF (HF hospitalization or urgent HF visit) or cardiovascular death. In this pre-specified analysis of participants with T2D, treatment effects were assessed by number and class of background GLT(s). Of 3150 participants with T2D at baseline, 22.9% were on no GLT, 36.5% were treated with 1 GLT, and 40.6% with ≥2 GLTs. During follow-up (median: 2.3 years), treatment benefits of dapagliflozin (vs. placebo) on the primary outcome were consistent irrespective of the number of background GLTs (0 GLTs: hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.50-1.00; 1 GLT: HR 1.04, 95% CI 0.80-1.34; ≥2 GLTs: HR 0.71, 95% CI 0.56-0.90; pinteraction = 0.59). Similar findings were observed among participants with (HR 0.73, 95% CI 0.59-0.92) and without background metformin use (HR 0.89, 95% CI 0.72-1.11; pinteraction = 0.22) and in participants with (HR 0.89, 95% CI 0.69-1.16) and without background insulin use (HR 0.78, 95% CI 0.65-0.95; pinteraction = 0.45). Dapagliflozin was well-tolerated irrespective of the number of background GLTs. Dapagliflozin safely and consistently improved clinical outcomes among individuals with T2D and HF with LVEF >40% irrespective of the number and class of background GLTs, and the benefits were not influenced by concomitant metformin or insulin use. These data bolster contemporary guidelines supporting first-line SGLT2i among individuals with T2D and HF, irrespective of background GLT.

Pulmonary Hypertension and Anastrozole (PHANTOM): A Randomized, Double-Blind, Placebo-Controlled Trial.

Inhibition of aromatase with anastrozole reduces pulmonary hypertension in experimental models. We aimed to determine whether anastrozole improved six-minute walk distance (6MWD) at six months in pulmonary arterial hypertension (PAH). We performed a randomized, double-blind, placebo-controlled Phase II clinical trial of anastrozole in subjects with PAH at seven centers. Eighty-four post-menopausal women and men with PAH were randomized in a 1:1 ratio to receive anastrozole 1 mg or placebo by mouth daily, stratified by sex using permuted blocks of variable sizes. All subjects and study staff were masked. The primary outcome was the change from baseline in 6MWD at six months. Using intent-to-treat analysis, we estimated the treatment effect of anastrozole using linear regression models adjusted for sex and baseline 6MWD. Assuming 10% loss to follow-up, we anticipated having 80% power to detect a difference in the change in 6MWD of 22 meters. Forty-one subjects were randomized to placebo and 43 to anastrozole and all received the allocated treatment. Three subjects in the placebo group and two in the anastrozole group discontinued study drug. There was no significant difference in the change in 6MWD at six months (placebo-corrected treatment effect -7.9 m, 95%CI -32.7 - 16.9, p = 0.53). There was no difference in adverse events between the groups. Anastrozole did not show a significant effect on 6MWD compared to placebo in post-menopausal women and men with PAH. Anastrozole was safe and did not show adverse effects. Clinical trial registration available at www. gov, ID: NCT03229499.

Dexmedetomidine, an alpha-2 adrenoceptors agonist, provides a neuroprotective effect for dopaminergic neurons in the substantia nigra and attenuates glucose imbalance in the 6-hydroxydopamine animal model of Parkinson’s disease

ABSTRACT Introduction Studies have shown that dexmedetomidine (DEX, an a2-adrenoceptors agonist) provides a neuroprotective effect and influences blood glucose levels. Here, we evaluated the effect of prolonged treatment with low doses of DEX on the survival rate of dopaminergic (DAergic) neurons in the substantia nigra and also serum glucose levels in 6-hydroxydopamine (6-OHDA) – induced Parkinson’s disease (PD) in the rat. Material and Methods The neurotoxin of 6-OHDA was injected into the medial forebrain bundle by stereotaxic surgery. DEX (25 and 50 µg/kg, i.p) and yohimbine, an a2-adrenoceptor antagonist (1 mg/kg, i.p) were administered before the surgery to the 13 weeks afterward. Apomorphine-induced rotational tests and blood sampling were carried out before the surgery and multiple weeks after that. Thirteen weeks after the surgery, the rats’ brain was transcardially perfused to assess the survival rate of DAergic neurons using the tyrosine hydroxylase (TH) immunohistochemistry. Results DEX remarkably attenuated the severity of rotational behavior and reversed the progress of the PD. It also increased the number of TH-labeled neurons by up to 60%. The serum glucose levels in 6-OHDA-received rats did not change in the third and seventh weeks after the surgery but decreased significantly in the thirteenth week. Treatment with DEX prevented this decrement in glucose levels. On the other hand, Treatment with yohimbine did not affect PD symptoms and glucose levels. Conclusion Our data indicate that DEX through neuroprotective activity attenuates the severity of 6-OHDA-induced PD in rats. DEX might also prevent hypoglycemia during the progress of the PD.

Immunomodulating effects of the single bacterial strain therapy EDP1815 on innate and adaptive immune challenge responses-a randomized, placebo-controlled clinical trial.

The gut microbiome can modulate systemic inflammation and is therefore target for immunomodulation. Immunomodulating effects of EDP1815, a bacterial commensal strain of Prevotella histicola, were studied in healthy participants. Effects on adaptive immunity were evaluated by a neo-antigen challenge with keyhole limpet haemocyanin (KLH), while effects on innate immunity were evaluated by topical toll-like receptor 7 (TLR7) agonist imiquimod. Capsules with two enteric coating levels (EC1, EC2) were compared.Thirty-six healthy participants were included and received a daily dose of 8 × 1010 cells EDP1815-EC1, EDP1815-EC2 or placebo (randomization 1:1:1) for 60 days. They received KLH vaccinations at days 8, 24 and 36, with intradermal skin challenge at day 57. KLH challenge outcomes were antibody levels, and skin blood flow and erythema after skin challenge, measured by imaging techniques. Imiquimod administration started at day 57, for 72 h. Outcomes consisted of imaging measurements similar to the KLH challenge, and the influx of inflammatory cells and cytokines in blister fluid.There was no effect of EDP1815 treatment on the KLH challenge, neither on the imaging outcomes of the imiquimod challenge. There was a consistently lower influx of inflammatory cells in the blister fluid of EDP1815-treated participants (neutrophils, p = 0.016; granulocytes, p = 0.024), more pronounced in EC1. There was a lower influx of interleukin [IL]-1β, IL-6, IL-8, IL-10, interferon [IFN]-γ and tumour necrosis factor in blister fluid of EDP1815-treated participants.EDP1815 had immunomodulatory effects on the innate immune response driven by imiquimod, but no effect on the KLH challenge was observed. Trial registration number: NCT05682222; date: 22 July 2022.

How does intergenerational coresidence affect the physical health of middle-aged children? Evidence from China

ABSTRACT Due to increasing longevity and decreasing fertility, the middle-aged generation has emerged as the primary caregivers for their elderly parents in China. Using the China Health and Retirement Longitudinal Survey, this study employs an endogenous treatment effect model to estimate the causal impact of intergenerational coresidence on the physical health of middle-aged children. The findings reveal that coresidence significantly deteriorates the physical health of middle-aged children. Notably, this effect is more pronounced in employed individuals compared to unemployed ones. Marginal effect analysis uncovers that coresidence has adverse effects on middle-aged children who are either particularly healthy or particularly unhealthy, while the marginal impact of coresidence on children in average health conditions is insignificant.

Multilevel Intervention Stepped Wedge Designs (MLI-SWDs).

Multilevel interventions (MLIs) hold promise for reducing health inequities by intervening at multiple types of social determinants of health consistent with the socioecological model of health. In spite of their potential, methodological challenges related to study design compounded by a lack of tools for sample size calculation inhibit their development. We help address this gap by proposing the Multilevel Intervention Stepped Wedge Design (MLI-SWD), a hybrid experimental design which combines cluster-level (CL) randomization using a Stepped Wedge design (SWD) with independent individual-level (IL) randomization. The MLI-SWD is suitable for MLIs where the IL intervention has a low risk of interference between individuals in the same cluster, and it enables estimation of the component IL and CL treatment effects, their interaction, and the combined intervention effect. The MLI-SWD accommodates cross-sectional and cohort designs as well as both incomplete (clusters are not observed in every study period) and complete observation patterns. We adapt recent work using generalized estimating equations for SWD sample size calculation to the multilevel setting and provide an R package for power and sample size calculation. Furthermore, motivated by our experiences with the ongoing NC Works 4 Health study, we consider how to apply the MLI-SWD when individuals join clusters over the course of the study. This situation arises when unemployment MLIs include IL interventions that are delivered while the individual is unemployed. This extension requires carefully considering whether the study interventions will satisfy additional causal assumptions but could permit randomization in new settings.

Transforming Adolescent Smiles: Correcting Skeletal Mandibular Retrusion and Bimaxillary Protrusion with Clear Aligners.

Maxillary protrusion combined with mandibular retraction is a highly prevalent but extremely complex maxillofacial deformity that can have a serious negative impact on patients' facial aesthetics and mental health. The traditional orthodontic treatment strategy often involves extracting 4 first premolars and conventional fixed techniques, combined with mini-implant screws, to retract the anterior teeth and improve facial protrusion. In recent years, an invisible orthodontic technique, without brackets, has become increasingly popular. However, while an invisible aligner has been used in some cases with reasonable results, there remain significant challenges in achieving a perfect outcome. This case report presents an adolescent patient with bimaxillary protrusion and mandibular retrognathia. Based on the characteristics of the invisible aligners and the growth characteristics of the adolescent's teeth and jawbone, we designed precise three-dimensional tooth movement and corresponding resistance/over-correction for each tooth, while utilizing the patient's jawbone growth potential to promote rapid development of the mandible, accurately and efficiently correcting bimaxillary protrusion and skeletal mandibular retrognathia. The patient's facial aesthetics, especially the lateral morphology, have been greatly improved, and various aesthetic indicators have also shown significant changes, and to the patient's great benefit, invasive mini-implant screws were not used during the treatment. This case highlights the advantages of using invisible aligners in adolescent maxillary protrusion combined with mandibular retraction patients. Furthermore, comprehensive and accurate design combined with good application of growth potential can also enable invisible orthodontic technology to achieve perfect treatment effects in tooth extractions, providing clinical guidance for orthodontists.

On-treatment analysis of torsemide versus furosemide for patients hospitalized for heart failure: A post-hoc analysis of TRANSFORM-HF.

The TRANSFORM-HF trial demonstrated no significant outcome differences between torsemide and furosemide following hospitalization for heart failure (HF), but may have been impacted by non-adherence to the randomized diuretic. The current study sought to determine the treatment effect of torsemide versus furosemide using an on-treatment analysis inclusive of all randomized patients except those confirmed non-adherent to study diuretic. TRANSFORM-HF was an open-label, pragmatic randomized trial of 2859 patients hospitalized for HF from June 2018 through March 2022. Patients were randomized to a loop diuretic strategy of torsemide versus furosemide with investigator-selected dosage. This post-hoc on-treatment analysis included all patients alive with either known or unknown diuretic status, and excluded patients confirmed to be non-adherent to study diuretic. This modified on-treatment definition was applied separately at time of hospital discharge and 30-day follow-up. All-cause mortality and hospitalization outcomes were assessed over 12 months. Overall, 2570 (89.9%) and 2374 (83.0%) patients were included in on-treatment analyses at discharge and 30-day follow-up, respectively. There was no significant difference in all-cause mortality between torsemide and furosemide in patients on-treatment at discharge (17.5% vs. 17.8%; hazard ratio [HR] 1.01 [95% confidence interval [CI] 0.83-1.22], p = 0.96) and at 30-day follow-up (14.5% vs. 15.0%; HR 1.02 [95% CI 0.81-1.27], p = 0.90). All-cause mortality or all-cause hospitalization was similar between torsemide and furosemide in patients who were on-treatment at discharge (58.3% vs. 61.3%; HR 0.92 [95% CI 0.82-1.03]) and 30-day follow-up (60.9% vs. 64.4%; HR 0.93 [95% CI 0.82-1.05]). In patients who were on-treatment at 30-day follow-up, there were 677 total hospitalizations in the torsemide group and 686 total hospitalizations in the furosemide group (rate ratio 0.99 [95% CI 0.86-1.14], p = 0.87). In TRANSFORM-HF, a post-hoc on-treatment analysis did not meaningfully differ from the original trial results. Among those deemed compliant with the assigned diuretic, there remained no significant difference in mortality or hospitalization after HF hospitalization with a strategy of torsemide versus furosemide. ClinicalTrials.gov Identifier: NCT03296813.

Upadacitinib in Active Non-radiographic Axial Spondyloarthritis: 1-Year Data From a Double-Blind, Randomized, Placebo-Controlled, Phase 3 Trial.

Upadacitinib improved the signs and symptoms of non-radiographic axial spondyloarthritis (nr-axSpA) versus placebo over 14 weeks in the primary analysis of the SELECT-AXIS 2 nr-axSpA study. Here, we evaluated the efficacy and safety of upadacitinib through 1 year in patients with nr-axSpA in SELECT-AXIS 2. Patients aged at least 18 years diagnosed with nr-axSpA who fulfilled the 2009 Assessment of SpondyloArthritis International Society (ASAS) classification criteria and were receiving stable background therapy were randomized to upadacitinib 15 mg once daily or placebo for the 52-week double-blind period. Efficacy was assessed using non-responder imputation incorporating multiple imputation (NRI-MI) and as-observed analyses for binary endpoints, and mixed-effects model repeated measures for continuous endpoints. Of 314 randomized patients, 259 (upadacitinib, n = 129; placebo, n = 130) completed 52 weeks of treatment. More patients receiving upadacitinib versus placebo achieved ≥40% improvement in ASAS at week 52 (63% vs 43%, NRI-MI; nominal P < 0.001). Similar treatment effects were observed for the achievement of axSpA Disease Activity Score inactive disease (33% v 11%, NRI-MI; nominal P < 0.001). Overall, patients receiving upadacitinib versus placebo showed greater improvement in disease activity, inflammation, pain, function, enthesitis, and quality of life through 52 weeks. Adverse events were generally comparable between the treatment groups. No opportunistic infections, malignancies, major adverse cardiovascular events, venous thromboembolic events, inflammatory bowel disease, or deaths were reported in those receiving upadacitinib. Treatment with upadacitinib showed sustained efficacy versus placebo with no new safety findings identified through 1 year. These results support the continued favorable benefit-risk profile of upadacitinib treatment for nr-axSpA.

Heterogeneity, Bayesian thinking, and phenotyping in critical care: A primer.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. To familiarize clinicians with the emerging concepts in critical care research of Bayesian thinking and personalized medicine through phenotyping and explain their clinical relevance by highlighting how they address the issues of frequent negative trials and heterogeneity of treatment effect. The past decades have seen many negative (effect-neutral) critical care trials of promising interventions, culminating in calls to improve the field's research through adopting Bayesian thinking and increasing personalization of critical care medicine through phenotyping. Bayesian analyses add interpretive power for clinicians as they summarize treatment effects based on probabilities of benefit or harm, contrasting with conventional frequentist statistics that either affirm or reject a null hypothesis. Critical care trials are beginning to include prospective Bayesian analyses, and many trials have undergone reanalysis with Bayesian methods. Phenotyping seeks to identify treatable traits to target interventions to patients expected to derive benefit. Phenotyping and subphenotyping have gained prominence in the most syndromic and heterogenous critical care disease states, acute respiratory distress syndrome and sepsis. Grouping of patients has been informative across a spectrum of clinically observable physiological parameters, biomarkers, and genomic data. Bayesian thinking and phenotyping are emerging as elements of adaptive clinical trials and predictive enrichment, paving the way for a new era of high-quality evidence. These concepts share a common goal, sifting through the noise of heterogeneity in critical care to increase the value of existing and future research. The future of critical care medicine will inevitably involve modification of statistical methods through Bayesian analyses and targeted therapeutics via phenotyping. Clinicians must be familiar with these systems that support recommendations to improve decision-making in the gray areas of critical care practice.

Longitudinal assessment of real-world patient adherence: a 12-month electronic patient-reported outcomes follow-up of women with early breast cancer undergoing treatment

BackgroundElectronic patient-reported outcomes (ePROs) assess patients’ health status and quality of life, improving patient care and treatment effects, yet little is known about their use and adherence in routine patient care.AimsWe evaluated the adherence of invasive breast cancer and ductal carcinoma in situ (DCIS) patients to ePROs follow-up and whether specific patient characteristics are related to longitudinal non-adherence.MethodsSince November 2016, the Breast Center at Charité – Universitätsmedizin Berlin has implemented an ongoing prospective PRO routine program, requiring patients to complete ePROs assessments and consent to email-based follow-up in the first 12 months after therapy starts. Frequencies and summary statistics are presented. Multiple logistic regression models were performed to determine an association between patient characteristics and non-adherence.ResultsOut of 578 patients, 239 patients (41.3%, 95%CI: 37.3–45.5%) completed baseline assessment and all five ePROs follow-up during the first 12 months after therapy. On average, above 70% of those patients responded to the ePROs follow-up assessment. Adherence to the ePROs follow-up was higher during the COVID-19 pandemic than in the time periods before (47.4% (111/234) vs. 33.6% (71/211)). Factors associated with longitudinal non-adherence were younger age, a higher number of comorbidities, no chemotherapy, and a low physical functioning score in the EORTC QLQ-C30 at baseline.ConclusionsThe study reveals moderate adherence to 12-month ePROs follow-up assessments in invasive early breast cancer and DCIS patients, with response rates ranging from 60 to 80%. Emphasizing the benefits for young patients and those with high disease burdens might further increase adherence.

The Effect of Different Chemical Surface Treatments on the Bond Strength of Resin-Matrix Ceramic Repaired with Resin Composite.

This study investigates the effect of different chemical surface treatment protocols with different functional monomers of universal adhesives on the shear bond strength between resin-matrix ceramic and resin composite. Eighty resin-matrix ceramics (Shofu block HC) were built and designed into eight groups of ten specimens and surface treated with HC primer (HC) and/or three universal adhesives (single bond universal [SBU], Scotchbond universal plus [SBP], and Tetric N-bond universal [TNU]) assigning follows; group 1, nonsurface treated; group 2, HC; group 3, SBU; group 4, HC + SBU; group 5, SBP; group 6, HC + SBP; group 7, TNU; group 8, HC + TNU. A template was put on the specimen center, and then pushed packable resin composite. Mechanical testing machinery was used to examine the samples' shear bond strength (SBS) values. To examine failure patterns, the debonded specimen surfaces were examined by a stereomicroscope. The one-way analysis of variance method was used to evaluate the data, and the Tukey's test was used to determine the significant level (p < 0.05). The highest SBS was obtained in group 6 (39.25 ± 1.65 MPa). Group 1 (4.15 ± 0.54 MPa) had the lowest SBS. Group 6 exhibited the highest percentage of cohesive failure patterns (70%). High SBS values were frequently correlated with the surface treatment groups and the cohesive failure patterns. The application of HC primer prior to the universal adhesive is an alternative protocol for enhancing the repair bond strength between resin-matrix ceramic and resin composite interfaces. Moreover, the application of HC primer prior to the SBP is the best strategy for resin-matrix ceramic and resin composite repairs.

Iron and bones: Effects of iron overload, deficiency and anemia treatments on bone

Iron and bones: Effects of iron overload, deficiency and anemia treatments on bone

Effect of Chemical Treatments on the Mechanical Properties of Jute/Polyester Composites

Effect of Chemical Treatments on the Mechanical Properties of Jute/Polyester Composites

“Outcome of non-surgical periodontal treatment on Gal-1 and Gal-3 GCF levels in periodontitis patients: a case-control study”

ObjectivesThis study aimed to explore the effect of nonsurgical periodontal treatment on Galectin-1 and -3 GCF levels in gingivitis and periodontitis stage III compared to periodontally healthy individuals, to determine whether they could serve as diagnostic markers / therapeutic targets for periodontitis and revealing their possible role in periodontal disease.Materials and methodsForty-five systemically healthy participants were included and equally subdivided into three groups: gingivitis, periodontitis (stage III), and a periodontally healthy control group. The clinical parameters were recorded. Galectin-1 and -3 GCF levels were evaluated (before and after non-surgical treatment for periodontitis) using an enzyme linked immune-sorbent assay (ELISA) kit. Receiver operating characteristic (ROC) curve was performed to reveal sensitivity, specificity, predictive value, and diagnostic accuracy of both markers.ResultsThe study showed statistical significance between different groups regarding Galectin-3 with higher values in periodontitis and the lowest values in healthy control. Also, Galectin-1 was significantly higher in the periodontitis/gingivitis groups than in the control group. Moreover, non-surgical periodontal treatment in periodontitis patients caused a statistical reduction in clinical parameters and biomarkers. ROC analysis revealed excellent diagnostic ability of both biomarkers in discriminating periodontitis/gingivitis against healthy individuals (100% diagnostic accuracy for Galectin-1 and 93% for Galectin-3, AUC > 0.9) and acceptable diagnostic ability between periodontitis participants against gingivitis (73% diagnostic accuracy for Gal-1 and 80% for Gal-3, AUC > 0.7).ConclusionsBoth Galectin-1 and Galectin-3 seem to have outstanding diagnostic accuracy for the identification of periodontal disease, an acceptable ability to measure periodontal disease activity and the severity of inflammatory status. Additionally, they could serve as therapeutic targets to monitor treatment efficiency.Clinicaltrial.gov registration number(NCT06038812).

Inactivation effects of combined thermosonication and potassium sorbate treatments on Bacillus subtilis spores

Inactivation effects of combined thermosonication and potassium sorbate treatments on Bacillus subtilis spores

Pore structure response at different scales in coal to cyclical liquid nitrogen treatment and its impact on permeability and micromechanical properties

The methane in the coal seams of abandoned mines is a valuable natural gas resource. However, the ultra-low permeability of coal seams restricts the extraction of coalbed methane. The liquid nitrogen fracturing technology is a novel approach suitable for enhancing the permeability of coal seams in abandoned mines. The ultra-low temperature could potentially facilitate the growth and propagation of pores and fractures in coal seams. In this study, we observed inconsistent alterations in coal properties measured by multiple instruments at different scales, whether in dry or wet coal specimens. This suggests that the mechanisms influencing the pore structure due to LN2 treatment differ across various scales in dry and wet coal specimens. For dry specimens, heterogeneous thermal deformation and freezing shrinkage exhibited opposing effects during LN2 treatment. Thermal stress-induced micro-fractures might counteract the freezing contraction of micropores in coal matrices, preventing a significant decrease in coal macropores and fractures. In wet specimens, the effects of LN2 treatment on wet coal specimens were predominantly controlled by frost heaving. However, due to low water saturation, LN2 treatment had negligible effects on coal micropores, even in the presence of local frost heaving. In field applications, water migration from smaller to larger pores could further diminish the impact of LN2 treatment on micropores.

Correction: Effect of Heat Treatment on Microstructure and Properties of Rolled Mg-4Y-3Nd-1.5Al Alloy

Correction: Effect of Heat Treatment on Microstructure and Properties of Rolled Mg-4Y-3Nd-1.5Al Alloy

The effect of sand-crumb rubber mixture treatment on the seismic response of a low-rise building located on liquefiable soil

One of the most effective measures to reduce earthquake risks in high-seismic areas is to reduce the input forces caused by earthquakes to the structure. The properties of rubber materials in geotechnical projects are energy absorption, dynamic deformation change as well as damping of latent energy in loads, high shear modulus and damping ratio, easy access and their economic nature. In this research, with finite difference modeling, the effect of using sand- crumb rubber layer on the seismic behavior of the model has been obtained. In the following, by changing the thickness and depth of the sand-crumb rubber layer, the seismic behavior such as floor displacement and internal forces have been investigated. This research numerically models liquefaction (UBCsand with FLAC) and predicts the effects of the sand-crumb rubber layer of different thicknesses (as % weight of the mixture) under the foundation and evaluates the structure's damage and settlement interacting with the soil by validating the numerical model with the laboratory model and calibrating it with different ratios. The results show that liquefaction, pore water pressure excess ratio and soil settlement will be significantly reduced with the presence of sand-crumb rubber layer, and also the base shear has shown an increase, but the structural damage is reduced.Graphical