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Study on progressive collapse resistance of steel beam-column structures with column tree connection under edge column failure
No full textTo investigate the progressive collapse resistance of steel frames with tree connections subjected to edge column failure along the major axis, ensuring the safety of structures under extreme conditions such as impact loads and fires, three full-scale beam-column substructures were designed and tested. The test variables included the presence of lateral restraints and temperature levels. Results indicate that edge column along the major axis failure transforms the substructure into an ultra-long cantilever beam, relying solely on flexural mechanisms for collapse resistance, unlike structures subjected to center column failure which benefit from catenary action. At room temperature, specimens without lateral restraints experienced overall instability, whereas lateral restraints shifted the failure mode to local buckling at the beam end, increasing bearing capacity by 13.1 %. Under high temperatures, laterally restrained substructures still exhibited overall instability due to material degradation. Finite element analysis further revealed that while vertical load magnitude minimally affects failure modes at high temperatures, fire resistance decreases with the vertical load increase on the failed column. When the beam end load increased from 18.68 kN to 32.69 kN, the critical temperature of the substructure decreased by 70℃. Finally, calculation methods for room temperature bearing capacity and load-dependent critical temperature are proposed. Validation against test and FEA results confirmed high accuracy
Behavior of two-storey welded steel frames strengthened with external prestressed strands
No full textA possible solution for enhancing the resistance of welded steel frames against progressive collapse is external installation of prestressed strands. Although several experimental studies have been conducted on steel frames with prestressed strands, most of these studies have focused only on individual joints or single-story substructures, while neglecting the interaction between different stories in multi-story frames. The objective of this research is to conduct a detailed study on the impact of prestressed strands on the progressive collapse resistance of welded steel frame structures. Pushdown tests were performed on two-story steel frame substructures with and without prestressed strand strengthening. Additionally, corresponding numerical models were established using LS-DYNA. Further parametric analyses were conducted to investigate the effects of prestressing level, strand diameter, layout type, and lateral restraint stiffness on the collapse resistance. The results show that the load-carrying capacity of frames strengthened with prestressed strands is higher than that of bare steel frames, which is mainly attributed to the significant enhancement of the frame's catenary action (CA) capacity after prestressed strand strengthening. Furthermore, analysis of horizontal reaction forces indicates that there are differences in the CA resistance among different stories. Through numerical analyses, it is concluded that compared with polyline and diagonal layouts, the straight and parallel layout provide a more significant enhancement in the load resistance of steel frames
Contrast enhancement potential of food-based imaging agents in cholangiopancreatography and digestive tract investigations using MRI: A systematic literature review and meta-analysis
Full text linkObjective To evaluate the contrast enhancement potential of food-based substances (FBS) as clinical imaging agents in MR cholangiopancreatography (MRCP) and digestive tract investigations. Methods A systematic literature search was conducted using a pre-defined strategy and inclusion criteria to identify relevant articles . Two review authors independently screened and selected papers for inclusion, conducted risk of bias assessment using ROBINS-I (Risk of Bias In Non-randomised Studies of Interventions) tool and assessed certainty of evidence using the Cochrane’s GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Areas of disagreement were resolved through consensus and the involvement of a third reviewer. The data obtained were meta -analysed using both random and fixed effects models with inverse variance methods, depending on the included studies’ methodological heterogeneity, to estimate the pooled mean difference and odds ratio. Results 16 studies (1360 participants) were included in this review. Eight studies each examined the effectiveness of FBS for contrast enhancement in MRCP and MRE, respectively. The pooled mean differences between MRCP with pineapple juice and non-contrast MRCP were 1.04 (95 % CI: 0.23, 1.84; I2 = 96 %, p ' 0.01) for bile duct visibility and 0.95 (95 % CI: 0.04, 1.85; I2 = 95 %, p ' 0.01) for pancreatic duct visibility. Compared to non-contrast MRCP, MRCP with pineapple juice showed improved pancreaticobiliary duct visibility (Combined odds ratio, 5.01; 95 % CI: 2.34, 10.64; p ' 0.0001). However, when compared with synthetic contrast agents, there is a lower likelihood of obtaining excellent quality MRE images with food-based contrast agents (FBCAs) (odds ratio, 0.36; 95 % CI: 0.18, 0.73, 0.73; p = 0.004). A generally high safety and acceptance profile was reported across the included studies for FBCAs. The certainty of the evidence obtained was considered moderate across all outcomes. Conclusion Oral administration of pineapple juice improves the diagnostic quality of MRCP investigations, while the contrast enhancement potential of FBS is limited in MRE studies. The high heterogeneity of results and moderate certainty of the evidence, however, require a cautious admission of results. Therefore, further research is necessary to gain a comprehensive understanding of the reliability of FBS in these MRI investigations, as well as in other imaging modalities that are yet to be explored
Understanding factors influencing medication adherence in Type 2 diabetes guided by the COM-B behaviour change model and assessed using the Morisky scale: A systematic review
Full text linkBackground
Type 2 Diabetes Mellitus (T2DM) requires a multifaceted management approach involving lifestyle modifications, education, and pharmacological treatments. Medication adherence is critical for achieving glycaemic control; however, up to 45 % of patients fail to meet HbA1c targets. The Morisky Medication Adherence Scale (MMAS) is a validated tool widely used in clinical practice to assess self-reported medication adherence, offering valuable insights into patient behaviours affecting treatment outcomes.
Aim
This systematic review evaluates medication adherence in adults with T2DM using the MMAS and to identify modifiable factors influencing non-adherence. The COM-B model was used to structure the analysis by mapping barriers and enablers to the Capability, Opportunity, and Motivation components that underpin medication-taking Behaviour.
Method
A systematic review was conducted following the PRISMA framework. MEDLINE, EMBASE, EMCARE, and Ovid Nursing databases were searched for cross-sectional studies published between January 2013 and December 2024 that utilised the MMAS scale to assess adherence in adults with T2DM receiving oral or injectable anti-glycaemic therapies. A narrative synthesis was conducted using the COM-B model to identify key barriers and enablers influencing adherence.
Results
Of 9990 records screened, 30 studies from 17 countries, involving 8405 participants, met the inclusion criteria. Overall, 40.9 % of participants demonstrated high adherence, while 42.6 % had low adherence. Key barriers included poor diabetes knowledge, depression, polypharmacy, side effects, inadequate patient-provider communication, and lack of continuity in care. Enablers encompassed patient education, family support, effective patient-provider communication, and structured diabetes education programmes.
Conclusions
The MMAS remains a reliable tool for assessing self-reported medication adherence in T2DM. However, adherence levels remain suboptimal. Addressing modifiable factors, such as depression, enhancing diabetes education, and improving healthcare communication, may improve adherence, glycaemic control, and overall T2DM management outcomes
Prospective study of individual characteristics and posttraumatic stress disorder (PTSD) symptoms following childbirth: Birth satisfaction as a moderator
Full text linkObjective: The goal of this study was to (a) examine the association between childbirth-related posttraumatic stress disorder (CB-PTSD) symptoms and possible risk factors of previous trauma, individual characteristics (neuroticism, anxiety sensitivity, and resilience), type of birth, and birth satisfaction and (b) explore whether birth satisfaction moderates any association between individual characteristics and CB-PTSD symptoms. Method: This was a longitudinal questionnaire study during pregnancy and postpartum. Pregnant women (N = 396) were recruited from antenatal clinics and completed questionnaires during mid–late pregnancy (Time 1) and 6–12 weeks after childbirth (Time 2). Time 1 questionnaires measured anxiety sensitivity (Anxiety Sensitivity Index), neuroticism (International Personality Item Pool–50, Neuroticism subscale), resilience (Brief Resilience Scale), and trauma history. Time 2 questionnaires measured birth satisfaction and CB-PTSD (Birth-Related and General Symptoms subscales). Results: Regression analysis showed that previous sexual trauma, higher levels of neuroticism, and lower levels of birth satisfaction predicted higher levels of CB-PTSD symptoms. Anxiety sensitivity and resilience were not significant predictors of CB-PTSD. Additionally, birth satisfaction moderated the relationship between higher neuroticism and higher levels of CB-PTSD (total and general symptoms) and between lower resilience and higher CB-PTSD general symptoms. Effects were stronger when low birth satisfaction was reported. Conclusions: Individual characteristics and birth satisfaction interact in the development of posttraumatic stress disorder following childbirth, with previous traumatic experiences playing an additional role. These findings can inform screening and care pathways for women at greater risk
Novel Genotype–Phenotype Correlations in CRB1-Retinopathies
Full text linkObjective/Purpose
This study evaluates genotype-phenotype correlations in CRB1-retinopathies using standardized phenotypic classification and comprehensive analysis of CRB1-A and CRB1-B involvement alongside in-silico protein modelling analysis.
Design
Retrospective multicentre cohort study.
Subjects
A total of 389 patients with biallelic disease-causing CRB1 variants from 50 international cohorts, including 73 patients from Moorfields Eye Hospital.
Methods
Phenotypes were reclassified using standardized diagnostic criteria. Genotype-phenotype correlations were assessed based on CRB1 isoform involvement and protein domain localisation of variants, supported by in-silico structural modelling.
Main Outcome Measures
Associations between CRB1 variant location, isoform involvement, and clinical phenotypes including Leber congenital amaurosis/early onset severe retinal dystrophy (LCA/EOSRD), retinitis pigmentosa (RP), cone-rod dystrophy (CRD), and macular dystrophy (MD).
Results
All patients had variants affecting CRB1-A, with none exclusively affecting CRB1-B. Mutations specific to CRB1-A, sparing CRB1-B were associated with macular dystrophy. Mutations in exons 6, 7, and 9 were associated to LCA/EOSRD and RP phenotypes, while exon 2 variants were linked to MD. Genotype-phenotype correlations included c.1841G>T p.(Gly614Val) linked to LCA/EOSRD and variants exclusively involving exon 11 and 12. Similarly, the variants c.2506C>A p.(Pro836Thr) and c.498_506del p.(Ile167_Gly169del) were linked to MD.
Conclusions
CRB1-A must be affected for disease manifestation; while sparing of CRB1-B leads to milder phenotypes. Novel genotype-phenotype correlations were found using standardized phenotypic classification. Understanding protein structure and isoform involvement is crucial for accurate diagnosis, prognosis, and the development of targeted therapies
Transcriptome-informed brain cartography of polygenic risk and association with brain structure in major psychiatric disorders
Full text linkPsychiatric disorders are complex, polygenic conditions characterized by patterned structural brain alterations. Whether these changes reflect transcriptional dysregulation driven by genetic risk remains unclear. We introduce a novel imaging-transcriptomics framework that integrates transcriptome-wide association studies (TWAS) with brain transcriptomic atlases to predict macroscale structural brain abnormalities across seven disorders: attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), anorexia nervosa (AN), bipolar disorder (BD), major depressive disorder (MDD), obsessive-compulsive disorder (OCD), and schizophrenia (SCZ). We generated disorder-related Gene Expression-based Disorder Associated Risk (GEDAR) maps and assessed their spatial correlation with observed brain alterations thereby establishing a structured approach to map polygenic transcriptional risk onto macroscale brain phenotypes. We found significant transcriptomic-anatomical correlations in MDD (cortical and subcortical), SCZ (subcortical), and ADHD (subcortical), indicating that regional transcriptional vulnerability might contribute to varying extents to the anatomical expression of genetic risk in these disorders. Pathway enrichment analysis on genetically predicted differentially expressed genes for those disorders where we found spatial correlations between GEDAR maps and observed structural changes revealed immune-related processes as dominant in MDD and SCZ, and neurodevelopmental pathways in ADHD. Importantly, spatial transcriptomic-anatomical alignment did not scale with between-disorder differences in heritability, pointing instead toward additional influences like developmental timing or environmental interactions. These findings underscore the potential and limitations of imaging transcriptomics as a framework for bridging the gap between genetic architecture and systems-level brain changes in psychiatric disorders
Study on Failure Mechanism and Dynamic Response of RC Shear Wall in Tall Buildings under Impact Load
Full text linkCurrently, there are few studies on the impact resistance of reinforced concrete (RC) shear walls in tall buildings. To this end, the dynamic response and failure mode of RC shear walls under impact load were investigated experimentally and numerically. Six specimens were tested using a specialized pendulum impact rig. The parametric study was conducted to reveal the effects of wall height, impact position, reinforcement ratio, drop height, and energy consumption. Based on the experimental results, an analytical model is established to predict the maximum displacement under impact load. Furthermore, more parameters were quantified by the verified numerical model using LS-DYNA. The obtained results show that the drop height and reinforcement ratio have a significant effect on the peak impact force. When the impact energy is constant, the energy absorption performance of the specimen is negatively correlated to the overall wall stiffness. The parametric results of LS-DYNA show that an increment of the axial compression ratio and wall width will significantly reduce the maximum displacement at the center of the wall. When the impact energy is low, increasing the impact velocity has a more significant effect on the displacement difference than the impact mass
The architecture of consent: The Ford Foundation, 'brain irrigation', and the making of India's neoliberal transition
No full textIndia’s transition from a statist, inward-oriented economy to one integrated with global markets is often explained by macroeconomic crisis and the failure of ‘license raj’. We argue that while crisis was the trigger, the form and resilience of India’s liberalisation were shaped by a decades-long project of elite knowledge network formation and preparation. Foregrounding the role of the Ford Foundation, we conceptualise its influence as building the institutional capacity for ‘brain irrigation’—a Gramscian process of hegemonic network construction, ideational transfer and elite cultivation that naturalised liberal economic thought as ‘common sense’. Through major grants (1952-1992), Ford, alongside Bretton Woods partners, supported the development of a cadre of Indian economists at institutions (including Delhi School of Economics, numerous Indian IIMs). This elite network, with figures like Patel, Ahluwalia, Bhagwati, and Singh, played pivotal roles in key episodes: 1966 devaluation, pro-business shifts in the 1980s, and 1991 reforms. Crucially, they also helped promote the move to liberalisation by moderating India’s stance on the New International Economic Order (NIEO). Using original archival records, we demonstrate how Ford’s long-term elite network investment did not cause liberalisation but provided the critical knowledge infrastructure that made a domestically-owned, sustainable market turn possible
Service providers views on changes in low vision service provision during and after the COVID-19 pandemic
Full text linkPurpose
To investigate Service Providers’ (SPs) experiences of, and views on, the impact of the COVID7 19 pandemic on provision of low vision (LV) assessments, and future provision post-pandemic.
Methods
A mixed methods approach employed two surveys (S1 and S2) and one-to-one semi-structured phone interviews. SPs were invited for S1 (LV assessments before and during pandemic) between June and August 2021, and S2 (post-pandemic services) in July 2022. Eleven purposively recruited SPs gave telephone interviews, assessing changes to LV assessments during the pandemic and how experiences could inform future services. Survey responses were tested for significant differences between proportions, and interviews analysed using thematic analysis.
Results
Eighty SPs, comprising clinical and non-clinical professionals, responded to S1, 27 to S2. Two themes emerged from interviews and surveys: early pandemic modifications and remote services. From S1, during the pandemic there was a significant increase (p<0.001) in the proportion of SPs providing LV assessments remotely (either alongside face-to-face provision, or remotely only), compared to pre-pandemic. S1, conducted while some COVID restrictions remained, also identified an increase in the proportion of LV assessments expected to be provided remotely post-pandemic compared to pre-pandemic (p<0.001). However, for S2, conducted after all restrictions were lifted, the increase in the proportion of LV assessments actually provided remotely post-pandemic was not statistically significant (p=0.20). Advantages (e.g. reduced risk of infection) and limitations (e.g. issues for hearing-impaired users) of remote LV assessments were highlighted
Conclusions
Remote LV assessments increased significantly during the pandemic and remained more common post- than pre-pandemic, though less common than anticipated. Many advantages were perceived, but guidance may need to be developed before remote services are more widely adopted
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