Regional Failure Research Articles

Survival outcomes and failure patterns for oropharyngeal cancers treated with simultaneous integrated boost in intensity modulated radiotherapy (SIB-IMRT) and concurrent chemotherapy.

Intensity modulated radiotherapy (IMRT) has become a standard radiotherapy treatment delivery option owing to the advantages it offers in terms of target coverage and organ sparing. Furthermore, the ability to introduce different fractionation for different targets lets us deliver higher doses to the high-risk areas and lower doses to the elective volumes at the same sitting, referred to as simultaneous integrated boost (SIB). In the current study, we intended to retrospectively analyze the clinical outcomes and patterns of the failure of oropharyngeal cancers treated with SIB-IMRT and concurrent chemotherapy at our centre and analyze the factors contributing to poorer outcomes. Data of oropharyngeal cancer patients treated with SIB-IMRT and concurrent chemotherapy were retrieved from the institutional database. Patient demographic details, histopathological features, staging, treatment details, failure patterns and outcomes were documented. All potential factors were evaluated for outcomes. Radiation was delivered by using the SIB-IMRT technique. High-risk planning target volume (PTV) received 66 Gy in 2.2 Gy/fraction, intermediate and low-risk PTV received 60 Gy and 54 Gy, respectively. Primary endpoint was to assess local control (LC), regional control (RC) and loco-regional control (LRC) rates and secondary end point was to evaluate the survival outcomes - overall survival (OS) and cancer-specific mortality. All survival analyzes were performed using the Kaplan-Meier method. A total of 169 cases were included in the final analysis. The median age was 55 years (range 20-78) with 95.3% males. The base of tongue was the most common primary site. Around 54% cases were node negative with 38% patients having stage IV disease. The local control rates for N0 vs. N+ cases were 74.1 vs. 62.3% (P = 0.046), respectively. Similarly, the 4-year RC rates for N0 vs. N+ cases were 94.4 vs. 83.5% (P = 0.024), respectively. On multivariate analysis, only 4-year RC rates showed significant difference between the two (P = 0.039). No differences were found between T stages in LRC and OS. The 4-year LRC rates for stages 1, 2 vs. 3, 4 were non-significant (69.2 vs. 66.3%; P = 0.178). The 4-year OS rate was 81.3%. The 4-year LC and LRC rates were 67.8 and 89.5%, respectively. There were 54 local and 17 regional failures. The median time to failure was 13 months (range 3.6-82.9). SIB-IMRT provides comparable outcomes for oropharyngeal cancers. OS and loco-regional recurrences were significantly worse for nodal positive disease.

Failure Analysis of CRDINiCr Butterfly Valves for Nuclear Power Plant Applications

Corrosion-resistant iron with nickel and chromium (CRDINiCr) is often used in butterfly valves for flow control at nuclear power plants, where resistance to corrosion, oxidation, and wear is significant. In this study, a failure analysis of a CRDINiCr alloy butterfly valve was performed by combining morphology characterization and in situ elemental composition analysis of failure of various regions of the valve. Based on the testing and analysis conducted in this study, it was determined that the inspected valve body material exhibited several defects, including poor graphitization, porosity, and the presence of eutectic carbides. These imperfections compromised the required plasticity criteria, resulting in significant embrittlement of the material. Therefore, under the impact stresses applied during the pressure testing, these vulnerabilities facilitated rapid crack initiation and propagation. The presence of such defects significantly compromised the material’s resistance to fracture under dynamic loading conditions, underscoring the critical importance of stringent quality control in the production of such materials to ensure their reliability and performance in operational settings at nuclear power plants.

Inhomogeneous Strain Behaviors of the High Strength Pipeline Girth Weld under Longitudinal Loading.

Unforeseen failures in girth welds present a significant challenge for the pipeline industry. This study utilizes 3D Digital Image Correlation (DIC) assisted cross-weld tensile testing to analyze the strain response of high-strength thick-walled pipelines, providing essential insights into the strain migration and fracture mechanisms specific to girth welds. The results reveal that the welding process significantly affects the mechanical distribution within the girth weld. The tested Shielded Metal Arc Welded (SMAW-ed) pipe exhibited undermatched girth welds due to high heat input, while Gas Metal Arc Welding (GMAW) introduced a narrower weld and Heat-Affected Zone (HAZ) with higher hardness than the base metal, indicative of overmatched girth welds. Strain migration, resulting from a combination of metallurgical heterogeneous materials and geometrical reinforcement strengthening, progressed from the softer HAZ to the base metal in the SMAW-ed sample with reinforcement, ultimately leading to fracture in the base metal. In contrast, the GMAW-ed sample shows no strain migration. Reinforcement significantly improves the tensile strength of girth welds and effectively prevents failure in the weld region. Sufficient reinforcement is crucial for minimizing the risk of failure in critical areas such as the weld metal and HAZ, particularly in SMAW-ed pipes.

Intra-treatment hypoxia directed major radiation de-escalation as definitive treatment for human papillomavirus-related oropharyngeal cancer.

6007 Background: We previously reported that surgery to the primary site with hypoxia-directed de-escalated radiation to the neck for human papillomavirus associated oropharyngeal carcinoma (HPV+ OPC) can lead to excellent oncologic outcomes. We now report the results of a successor multi-center phase II trial of hypoxia-directed de-escalated chemoradiotherapy without surgery for HPV+OPC. Methods: HPV+ OPC (T0-2/N1-N2c/AJCC 7th) patients were eligible for enrollment. Tumors without evidence of hypoxia on 18F-FMISO (fluoromisonidazole) PET received de-escalated chemoradiation to 30Gy while those with hypoxia received chemoradiation to 70Gy. The primary objective was achieving a 2-year locoregional control (LRC) of 95% (failure was locoregional recurrence where surgical salvage was unfeasible) with a 7% non-inferiority margin. We enrolled a total of 158 subjects upfront to account for a 5% loss due to death (of reasons other than cancer) or follow-up. Secondary objectives were local failure (LF), regional failure (RF), distant metastasis (DM), overall survival (OS), toxicities, and patient-reported MD Anderson Dysphagia Inventory (MDADI) scores. LF, RF, and DM were estimated using the Cumulative Incidence Function, and OS was estimated using the Kaplan-Meier method. Results were reported up to 1/31/2024. Results: From 4/28/20-4/17/23, 158 HPV+ OPC patients were enrolled where150 patients were eligible for analyses. Patient characteristics: Tonsil (43%); Base of Tongue (47%); unknown primary (10%); >/=10 pack years (22%); T0 (9%), T1 (44%), T2 (47%); N1 (14%), N2a (11%), N2b (59%), N2c (16%). 111 (74%) received 30Gy; 95% cisplatin. With 24 months (8-43) of median follow-up, the 2-year LF, RF, DM rates were 4.2%, 6.9%, 2.0%, respectively. The 2-year overall survival probability was 99%. Only 2 patients could not undergo salvage surgery [one 30Gy (second recurrence); one 70Gy (M1)], both received systemic therapy with durable response. Acute grade 3-4 toxicities were 32% (67% neutropenia). Mean MDADI scores: 92.93 (baseline); 68.24 (3 weeks), 91.45 (4 months) after chemoradiation. Conclusions: These early data indicate that major de-escalation to 30Gy based on hypoxia status achieved significant toxicity reduction without compromise in survival for HPV+ OPC treated with chemoradiation without surgery. Clinical trial information: NCT03323463 .

The Role of Elective Nodal Irradiation in Treating Clinically Node-Negative Sinonasal Squamous Cell Carcinoma

PurposeThis study aims to examine the role of elective nodal irradiation (ENI) in clinically node-negative (cN0) sinonasal squamous cell carcinoma (SNSCC) and to define the optimal radiation fields for ENI. Methods and MaterialsWe retrospectively reviewed 368 cN0 SNSCC patients treated between 2009 and 2021. The study evaluated the impact of ENI on overall survival (OS), progression-free survival (PFS), regional-failure-free survival (RFS), and distant metastasis-free survival (DMFS), along with the coverage areas of ENI. ResultsThe majority of patients underwent surgery (n=316, 85.9%), with 75% (n=276) having tumors in the maxillary sinus or nasal cavity and 67.7% (n=249) presenting with T4 disease. Additionally, 32.3% (n=119) of the tumors were poorly differentiated. The 5-year OS, PFS, RFS, and DMFS rates were 59.3%, 54.0%, 57.6%, and 58.8%, respectively. ENI was performed in 217 patients (59%), with sixteen experiencing neck relapse during follow-up. While ENI did not enhance survival rates, it significantly reduced the overall regional-failure rate (7.9% vs. 1.8%, χ2 =7.98, p<0.01) and the cumulative incidence of regional failure (p=0.045). Additionally, the subgroups with maxillary sinus origin (2.33% vs. 13.51%, p=0.025), T4 stage (1.80% vs. 8.54%, p=0.028), and poor differentiation (2.44% vs. 13.51%, p=0.029) had higher cumulative incidences of regional failure in patients without ENI. No significant difference was observed in survival and regional failure rates between patients treated with ENI to levels Ib and II with or without level III, as well as between cN0 patients with non-midline crossing lesions receiving unilateral or bilateral ENI. ConclusionsDespite no survival benefit, ENI significantly decreases the regional failure rate in cN0 SNSCC patients. For primary lesions not crossing the midline, ipsilateral ENI targeting levels Ib and II proves to be an effective strategy.

Contact x-ray brachytherapy for the treatment of rectal cancer: A systematic review and meta-analysis.

e15628 Background: Rectal cancer is a highly prevalent disease, particularly among the elderly and frail populations. While surgical resection has traditionally been the primary management approach, it carries inherent risks, including operative mortality, morbidity, and poor long-term functional outcomes. These risks are particularly pronounced in older, co-morbid individuals. Evidence presented in the 2023 phase III OPERA randomised trial suggests that Contact X-ray Brachytherapy (CXB) is a viable organ-preserving alternative to radical surgery. We conducted a systematic review and meta-analysis to assess the clinical effectiveness of CXB in the treatment of rectal cancer. Methods: This systematic review was prospectively registered (CRD42021284969) and reported in accordance with PRISMA guidelines. PubMed, EMBASE, SCOPUS and Cochrane CENTRAL Libraries were interrogated using the search terms “Rectal cancer”, “Contact Brachytherapy”, and synonym terms. Literature search and data extraction were conducted by two reviewers, with recourse to a senior author for resolution of conflicts. Clinical complete response (cCR) was the primary outcome. Secondary outcomes include local regrowth, regional recurrence, salvage surgery rates, long-term disease control post-salvage surgery and survival outcomes. Proportional meta-analyses were conducted and presented as forest plots with summary proportions and 95% confidence intervals. The Higgins I2 statistic was used to assess for heterogeneity. The random effects model was employed in studies reporting substantial heterogeneity (I2&gt; 50%). Results: The literature search identified 973 studies, of which 48 studies encompassing 5,447 patients were included in the meta-analysis. Pooled estimates of outcomes were as follows: cCR rate = 80% (95% CI 76-88%), local regrowth = 15% (95% CI 12-18%), regional failure rate = 3% (95% CI 2-4%), salvage surgery rate = 14% (95% CI 11-18%), long-term disease control post-salvage surgery rate = 88% (95% CI 78-96%) and organ preservation 82% (95% CI 75-88%). A subgroup analysis was conducted and stratified by concomitant therapy (CXB alone, CXB &amp; EBRT, CXB &amp; EBCRT). CXB, in conjunction with EBCRT, leads to a statistically significant reduction in both local regrowth and regional failure. The local regrowth rates were 16% (95% CI 11-21%), 17% (95% CI 11-23%), and 10% (95% CI 8-13%) respectively, with a p-value of 0.05. The regional failure rates were 4% (95% CI 2-8%), 4% (95% CI 2-5%), and 1% (95% CI 0-2%), p = 0.02. Conclusions: CXB, combined with EBCRT, in the appropriately selected patient can achieve long-term disease control whilst avoiding major surgery. Salvage surgery is a viable option for patients who experience disease regrowth, with excellent long-term disease control. CXB may be considered a safe alternative to surgery in the appropriately selected patient.

Adjuvant chemotherapy following concurrent chemoradiation (CRT) in patients with high-risk early-stage cervical carcinoma following radical hysterectomy: Results of NRG oncology/RTOG 0724/GOG-0724.

5504 Background: To assess the efficacy of adjuvant systemic chemotherapy following CRT for patients (pts) with high-risk early-stage cervical carcinoma. Methods: Pts with clinical stage IA2, IB, or IIA cervical carcinoma with at least one of the following high-risk features after radical hysterectomy: positive pelvic nodes, positive parametrium, and/or positive para-aortic nodes were stratified by intention to use brachy (yes v no), RT (Standard v IMRT); and RT dose (45 v 50.4 Gy) then randomized 1:1 to CRT or CRT and 4 cycles of adjuvant chemotherapy with paclitaxel and carboplatin (CRT + chemo). Primary endpoint was disease-free survival (DFS: death, local or regional failure, or distant mets). Reported secondary endpoints are OS (death due to any cause) and AEs (CTCAEv4). Sample size was 235 pts (50 DFS events, HR=0.47, corresponding to an increase in 4-year DFS from 80% to 90% for the CRT + chemo arm, 80% power, 1-sided log-rank α=0.05). Multivariable analysis (MVA) used Cox regression models. Results: From 9/16/2009 to 3/2/2022, this phase III international trial enrolled 236 pts, with 212 eligible/analyzed (109 CRT and 103 CRT + chemo). Median age was 46 yrs (min-max: 25-77) and median follow-up for all pts was 4.5 yrs (min-max: 0.02-12.8). Fifty-one percent of pts identified as white, 39% as Asian, and 6% Black. Most pts had squamous cell carcinoma (76%), with 18% adenocarcinoma and 5% adenosquamous. 56% of pts had open radical hysterectomy, 23% laparoscopic, and 22% robotic. Most pts had stage IB (87%) and 74% had positive pelvic nodes. Four (4%) pts on the CRT arm and 1 (1%) patient on CRT + chemo did not receive RT. The median (min-max) RT dose delivered was 50.4 Gy (7.2-60.4). Four pts (2 on each arm) did not receive concurrent cisplatin and 27 (26%) pts did not receive adjuvant carboplatin and paclitaxel on the CRT + chemo arm. Grade 3 and 4 events occurred in 36% and 7% of CRT pts; 44% and 21% in the CRT + chemo arm. There were 50 failures, 26 and 24 on the CRT and CRT + chemo arms, respectively, with 4-yr DFS estimates of 76% (90% CI: 69%, 83%) and 77% (90% CI: 70%, 84%) for the CRT and CRT + chemo arms, respectively (HR=1.05 [90% CI: 0.65, 1.68], p=0.56). Thirty-seven of 50 first failures were distant [74%], 20 (40%) and 17 (34%) in CRT and CRT + chemo arms, respectively. On MVA, factors that were statistically significant for worse DFS were receiving vaginal brachy (p&lt;0.0001), RT dose ≥50 Gy (p=0.0021), and adenocarcinoma histology (p=0.03). Pts receiving brachy had close or positive margins. The estimated 4-yrs OS is 87% (90% CI: 82%, 93%) and 89% (90% CI: 84%, 94%) for the CRT and CRT +chemo arms, respectively (HR=0.91 [90% CI: 0.49 to 1.69]; 1-sided log-rank p=0.40). Conclusions: The addition of systemic chemotherapy following CRT didn't improve DFS or OS in cervical cancer patients with high-risk factors after radical hysterectomy. Clinical trial information: NRG Oncology/RTOG 0724/GOG-0724.

Review of the Teduglutide screening process at a regional intestinal failure centre

Review of the Teduglutide screening process at a regional intestinal failure centre

Batch Job Active-Active Resiliency System and Method

This manuscript presents a robust solution for orchestrating batch job workflows in an active-active resiliency mode across multiple regions. The proposed system abstracts the complexities of job and step/task state management, provides automated and customizable retries, and ensures auditability and observability. The system maintains operational continuity and fault tolerance, leveraging lock marker files and a configurable scheduler, even during regional failures. This approach addresses the challenges of asynchronous workflow management, offering enhanced visibility, control, and efficiency in processing batch jobs.

Friction stir seam- and spot-welded aluminium honeycombs: Enhanced structural integrity eliminating adhesive bonding challenges

Aluminium honeycombs serve as a primary core material for energy absorption in various transportation and structural applications, with particular emphasis on their superior strength in the out-of-plane direction. However, conventional fabrication methods rely on adhesive bonding of aluminium strips, revealing poor bond strength under collapse stress. Premature structural failure arises from adhesive failure and subsequent debonding of cell walls, occurring before the aluminium strips fail. Addressing this, an innovative approach utilizing friction stir seam, and spot welding has been introduced to overcome adhesive bonding limitations. Welded joints exhibit a remarkable tenfold increase in strength compared to adhesive bonds. Notably, welded honeycombs demonstrate 32–37% higher crushing strength and an 80–84% increase in specific energy absorption capacity over adhesive-bonded variants. Collapse mechanisms involve pure buckling in seam-welded honeycombs without weld region failure, while spot-welded honeycombs display a combination of bending-shear and spot tearing, particularly evident with wider weld spacing. Obtaining longitudinal loading on seam-welded honeycomb walls is advantageous because of its 57% higher normalized maximum load capacity compared to the shear-tensile strength obtained for spot-welded walls. This study marks a significant advancement in the existing manufacturing route for honeycombs in achieving superior crushing performance.

Systematic evaluation and meta-analysis of the prognosis of down-staging human papillomavirus (HPV) positive oropharyngeal squamous cell carcinoma using cetuximab combined with radiotherapy instead of cisplatin combined with radiotherapy.

To evaluate the efficacy and safety of cetuximab instead of cisplatin in combination with downstaging radiotherapy for papillomavirus (HPV) positive oropharyngeal squamous cell carcinoma (HPV+ OPSCC). Meta-analysis and systematic evaluation. The PubMed, Embase, Web of Science, and Cochrane library databases were searched up to June 8, 2023, as well as Clinicaltrials.gov Clinical Trials Registry, China Knowledge Network, Wanfang Data Knowledge Service Platform, and Wiprojournal.com. Randomized controlled trials reporting results of standard regimens of cetuximab + radiotherapy vs cisplatin + radiotherapy in treating HPV+ OPSCC were included. The primary outcomes of interest were overall survival (OS), progression-free survival (PFS), local regional failure rate (LRF), distant metastasis rate (DM), and adverse events (AE). Two reviewers independently extracted data and assessed the risk of bias of the included studies. The HR and its 95% CI were used as the effect analysis statistic for survival analysis, while the OR and its 95% CI were used as the effect analysis statistic for dichotomous variables. These statistics were extracted by the reviewers and aggregated using a fixed-effects model to synthesise the data. A total of 874 relevant papers were obtained from the initial search, and five papers that met the inclusion criteria were included; a total of 1,617 patients with HPV+ OPSCC were enrolled in these studies. Meta-analysis showed that OS and PFS were significantly shorter in the cetuximab + radiotherapy group of patients with HPV+ OPSCC compared with those in the conventional cisplatin + radiotherapy group (HR = 2.10, 95% CI [1.39-3.15], P = 0.0004; HR = 1.79, 95% CI [1.40-2.29], P < 0.0001); LRF and DM were significantly increased (HR = 2.22, 95% CI [1.58-3.11], P < 0.0001; HR = 1.66, 95% CI [1.07-2.58], P = 0.02), but there was no significant difference in overall grade 3 to 4, acute and late AE overall (OR = 0.86, 95% CI [0.65-1.13], P = 0.28). Cisplatin + radiotherapy remains the standard treatment for HPV+ OPSCC. According to the 7th edition AJCC/UICC criteria, low-risk HPV+ OPSCC patients with a smoking history of ≤ 10 packs/year and non-pharyngeal tumors not involved in lymphatic metastasis had similar survival outcomes with cetuximab/cisplatin + radiotherapy. However, further clinical trials are necessary to determine whether cetuximab + radiotherapy can replace cisplatin + radiotherapy for degraded treatment in individuals who meet the aforementioned characteristics, particularly those with platinum drug allergies. CRD42023445619.

Association between tumor cell in air space and treatment outcomes in early-stage lung cancer treated with stereotactic body radiation therapy

Background and purposeSpread-through air space (STAS) is an unfavorable factor in patients with lung cancer treated with surgery. However, the relationship between the treatment outcomes of stereotactic body radiation therapy (SBRT) for lung cancer and STAS has not been adequately investigated. This study aimed to evaluate the impact of tumor cells in the air space (TCIAS), which show a STAS burden, on treatment outcomes in patients with early-stage lung cancer treated with SBRT. Materials and methodsData of patients who underwent SBRT for early-stage lung cancer treated with SBRT were retrospectively reviewed. The influence of the TCIAS status on local progression-free (LPF), regional failure-free (RFF), distant failure-free (DFF), progression-free survival (PFS), and overall survival (OS) rates was assessed using univariate and multivariate analyses. ResultsOverall, 68 patients were included. The median follow-up time was 24.3 months. For patients positive/negative for TCIAS, the 2-year LPF, RFF, DFF, PFS, and OS rates were 81.4 %/91.1 %, 73.7 %/96.2 %, 55.9 %/75.3 %, 55.0 %/84.6 %, and 67.8 %/92.2 %, respectively. In the multivariate analysis, TCIAS-positive was a significant unfavorable factor for RFF (hazard ratio [HR]: 4.10; 95 % confidence interval [CI]: 1.04–16.16, p = 0.04), DFF (HR: 2.61, 95 % CI: 1.03–6.57, p = 0.04), and PFS (HR: 2.36; 95 % CI: 1.05–5.30, p = 0.04). By contrast, TCIAS-positive was not a significant risk factor for LPF and OS. ConclusionTCIAS-positive is an unfavorable factor for regional and distant failure after SBRT. TCIAS status may be useful in predicting the treatment outcome of SBRT for early-stage lung cancer.

Resilience-based seismic design and cyclic behavior of assembled joints between self-compacting concrete-filled rectangular steel tube frame columns and H-shaped steel beams

The overall stability of prefabricated steel structures depends significantly on the strong seismic resilience exhibited by the connections between beams and columns. This paper introduces a novel beam–column connection approach, referred to as the welded upper and lower flanges and two diagonal web plates (WULF-TDWP). Unlike conventional methods, this approach replaces bolted connections with butt-welded joints between steel beams and employs short cantilever beams to achieve plastic hinge displacement. The steel-column cross-section was designed with a larger aspect ratio to better absorb and distribute energy. Six full-scale specimens were subjected to cyclic loading tests to investigate the seismic performance of the WULF-TDWP system. The main test parameters included the axial load ratio, welding configuration in the node region, and presence of reinforcement plates. The specimens exhibited two distinct failure modes: plate buckling deformation and beam–column end weld tearing. The experimental results included the hysteresis curves, skeleton curves, ductility coefficients, stiffness degradation curves, and strength degradation curves of the specimens. The experimental findings highlighted the favorable hysteresis performance, load-carrying capacity, and deformation capacity of all the nodes. Additionally, the plastic hinges were observed to shift, thereby delaying the premature failure of the node region. Notably, the omission of welding between the cantilever short beam flange and steel column significantly reduced the initial stiffness of the node. Through finite element analysis, the seismic performance of the beam-column joints with upper and lower flange welded connections and cantilever short beams was elucidated. The reliability of the finite element model for assessing the seismic performance of the nodes was confirmed through validation using experimental findings. Furthermore, this paper categorizes the nodes and introduces a simplified calculation model based on the moment–rotation method.

FATIGUE BOND LIFE OF REINFORCED CONCRETE BEAMS WITH LOW REINFORCEMENT CORROSION

Corrosion in reinforced concrete elements can result in a decrease in cross-sectional area and loss of bond between steel and concrete. The cumulative effects of fatigue loading can exacerbate the adverse impact on the bond characteristics between steel and concrete. In this study, the impact of reinforcement corrosion on the fatigue bond life of reinforced concrete members using lap-splice specimens is investigated. The beams are designed such that the failure of the control specimen occurs due to bond failure in the lap-splice region. Stirrups are provided in the lap-splice region to consider the influence of stirrup confinement on bond behavior. The longitudinal rebars and stirrups in the lap-splice region are subject to accelerated corrosion using the impressed current technique, respectively achieving approximately 5% and 15% mass loss. Subsequently, the beam specimens are tested under four-point loading, such that the lap-splice region falls under a constant moment zone. Under monotonic loading, the control specimen experiences abrupt failure due to bond failure. In fatigue loading, the corroded specimen exhibits a significant reduction of 98% in its fatigue life.

FATIGUE BOND LIFE OF REINFORCED CONCRETE BEAMS WITH LOW REINFORCEMENT CORROSION

Corrosion in reinforced concrete elements can result in a decrease in cross-sectional area and loss of bond between steel and concrete. The cumulative effects of fatigue loading can exacerbate the adverse impact on the bond characteristics between steel and concrete. In this study, the impact of reinforcement corrosion on the fatigue bond life of reinforced concrete members using lap-splice specimens is investigated. The beams are designed such that the failure of the control specimen occurs due to bond failure in the lap-splice region. Stirrups are provided in the lap-splice region to consider the influence of stirrup confinement on bond behavior. The longitudinal rebars and stirrups in the lap-splice region are subject to accelerated corrosion using the impressed current technique, respectively achieving approximately 5% and 15% mass loss. Subsequently, the beam specimens are tested under four-point loading, such that the lap-splice region falls under a constant moment zone. Under monotonic loading, the control specimen experiences abrupt failure due to bond failure. In fatigue loading, the corroded specimen exhibits a significant reduction of 98% in its fatigue life.

Platinum-based adjuvant chemoradiotherapy versus adjuvant radiotherapy in patients with head and neck adenoid cystic carcinoma

PurposeThe objective of the study was to assess the effectiveness and toxicity of platinum-based adjuvant chemoradiotherapy (POCRT) in comparison to postoperative radiotherapy (PORT) in patients with head and neck adenoid cystic carcinoma (HNACC).Materials and methodsThis retrospective study analyzed patients diagnosed with HNACC at our center between January 2010 and April 2020. A 1:1 propensity score matching method was used to create a matched cohort.ResultsIn this study, 206 patients were analyzed, with 147 patients (71.4%) receiving postoperative radiotherapy (PORT) and 59 patients (28.6%) receiving POCRT. Twenty-one patients experienced local–regional failure. The 3-, 5-, and 10-yr local–regional control (LRC) rate for the cohort were 92.0%, 90.6%, and 86.9%, respectively. In both the entire cohort and the matched cohort, the POCRT group exhibited superior LRC compared to the PORT group (Gray's test, all P < 0.05*). Multivariate analysis identified adjuvant concurrent chemotherapy as an independent prognostic factor for LRC (Competing risks regression, HR = 0.144, 95% CI 0.026–0.802, P = 0.027*). In addition, the POCRT group had higher incidences of upper gastrointestinal toxicity and hematologic toxicities, including leukopenia, neutropenia, and anemia (all P < 0.05*).ConclusionIn terms of reducing locoregional failures in HNACC patients, POCRT may potentially offer a more effective therapeutic approach than using PORT alone, although it also entails an augmented burden of treatment-related toxicity.

Study on the hysteretic characteristics of FRP-reinforced concrete shear wall with innovative friction dampers

FRP-reinforced concrete shear walls (FRCWs) are able to achieve satisfactory residual deformation and corrosion resistance compared with steel reinforced concrete walls (SRCWs). However, in the FRCWs, the failure of the plastic hinge region brings great challenges to the post-earthquake repair of the structure. Therefore, this paper designed one SRCW and two FRCWs with innovative friction dampers (FDs) at the feet, and steel truss and steel plate were embedded at the plastic hinge region of the two FRCWs respectively to supplement the weakened shear strength. Then pseudo-static tests were carried out twice before and after repairing the two FRCWs with FDs. Experimental results showed that compared with the SRCW at the same lateral drift, the damage of the FRCW was reduced by installing FDs at the feet, and the energy dissipation capacity was enhanced; the repaired FRCWs with FDs could still have acceptable seismic performance. Subsequently, the Park-Ang damage indices of wall webs of the FRCWs with FDs were calculated, which proved that the FRCWs with FDs could meet the four-level seismic fortification objective. In the end, two orthogonal tests were designed based on the established OpenSees models to evaluate the impact of the damper friction and FRP reinforcement ratio on the seismic behaviours of the FRCWs with FDs. It was recommended to adopt larger longitudinally distributed FRP reinforcement ratio to obtain satisfactory self-centering ability and hysteresis performance of the FRCW with FDs.

Analysis of multi-scale failure behavior of SiCf/SiC composite clad tube under flexible clamping damage

The intricate spatial fiber winding structure of SiCf/SiC ceramic matrix composite (CMC) cladding tubes makes it difficult to investigate in depth the inherent evolutionary mechanism of damage failure under specific operating conditions. Therefore, in this study, based on X-ray computed tomography (X-CT) reconstruction and cross scale numerical simulation methods, combined with clamping failure experiments under specific conditions for the cladding tubes, we conduct an in-depth analysis of the material's damage, failure, and mechanical behavior in different clamped regions. The research indicates that variations in the clamped regions have a minimal impact on the overall mechanical feedback of the material, and the maximum clamping load remains essentially around 500 N. The tube damage exhibits a unique " regional progressive damage evolution mechanism," where stress differentials of 108.49–115.33% appear between the inner and outer surfaces in different regions, leading to variations in the initiation and propagation of cracks within these areas. Furthermore, based on the minimum potential energy principle and semi-geodesic line theory, the intricate macroscopic tube structure formed by the spatial stacking and winding of SiCf/SiC cladding tube fibers is accurately reconstructed, which is combined with macroscale and microscale local feature models to capture the fibre/matrix morphology of the material with dynamic mechanical feedbacks, and experimentally validated in this work. The results indicate that the numerical model can effectively characterize the complex mechanical damage morphology and progressive failure lows of SiCf/SiC CMC at multiscale. Simultaneously, it is observed that stress concentrations in the fiber crossover region result in a load-bearing capacity 112–283% higher than in other areas. This phenomenon often leads to the first occurrence of failure in this region after clamping overload, exhibiting more pronounced damage characteristics.

Patterns of Failure After Prostate-Only Radiotherapy in High-Risk Prostate Cancer: Implications for Refining Pelvic Nodal Contouring Guidelines

PurposeTo study prostate specific membrane antigen – positron emission tomography (Ga68PSMA-PETCT) based patterns of relapse at biochemical failure (BCF) after prostate-only radiotherapy (PORT) in high-risk (HR) prostate cancer and its implications on pelvic contouring recommendations. Methods and materialsPatients with clinico-radiological high-risk node-negative prostate cancer treated with curative PORT and androgen deprivation therapy (ADT), either within the POP-RT randomised trial or off trial, who underwent a Ga68PSMA-PETCT upon BCF were included. Patterns of regional and distant recurrence on Ga68PSMA-PETCT were studied. Pelvic nodal recurrences were mapped with reference to the superior border of pubic symphysis. Pelvic lymph nodal caudal border (PLNcb) recommendations in the published contouring guidelines (RTOGcb, GETUGcb, PIVOTALcb, NRGcb, GFRUcb) were evaluated. ResultsOf the total 262 patients screened, 68 eligible patients were included (POP-RT trial 35 patients; off-trial 33 patients). Median follow-up was 91 months (IQR, 72–117) and median time to BCF was 65 months (IQR, 49–83). Regional and distant recurrence was seen in 31 (46%) and 31 (46%) patients, respectively. Of the nodal recurrences, nearly half (46%, 14/31) had no distant metastases and 64% (20/31) had a failure in the common iliac nodal region. The lower-most nodal recurrence was 20 mm cranial to the top of pubic symphysis (RTOGcb, GETUGcb, GFRUcb) and 10 mm cranial to the PIVOTALcb. The PLNcb recommended by NRG guideline (NRGcb) had an inter-patient variability of 32 mm, ranging from 16 mm above to 16 mm below the top of pubic symphysis, and the lower most nodal recurrence ranged from 4 mm to 36 mm cranial to NRGcb. ConclusionPelvic failures accounted for a major proportion of recurrences after prostate-only radiotherapy, with the caudal most nodal recurrence being 20 mm cranial to the top of pubic symphysis. This could have implications in defining the caudal border of contouring recommendations.

High-dose loco-regional pattern of failure after primary radiotherapy in p16 positive and negative head and neck squamous cell carcinoma – A DAHANCA 19 study

IntroductionPatients with failure after primary radiotherapy (RT) for head and neck squamous cell carcinoma (HNSCC) have a poor prognosis. This study investigates pattern of failure after primary curatively intended IMRT in a randomized controlled trial in relation to HPV/p16 status. Material and methodsPatients with HNSCC of the oral cavity, oropharynx (OPSCC), hypopharynx or larynx were treated with primary curative IMRT (+/-cisplatin) and concomitant nimorazole between 2007 and 12. Of 608 patients, 151 had loco-regional failure within five years, from whom 130 pairs of scans (planning-CT and diagnostic failure scan) were collected and deformably co-registered. Point of origin-based pattern of failure analysis was conducted, including distance to CTV1 and GTV, and estimated dose coverage of the point of origin. ResultsOf 130 patients with pairs of scans, 104 (80 %) had at least one local or regional failure site covered by 95 % of prescribed dose and 87 (67 %) of the failures had point of origin within the high-dose CTV (CTV1). Of failures from primary p16 + OPSCC, the majority of both mucosal (84 %) and nodal (61 %) failures were covered by curative doses. For p16− tumors (oral cavity, OPSCC p16neg, hypopharynx and larynx), 75 % of mucosal and 66 % of nodal failures were high-dose failures. ConclusionRadioresistance is the primary cause of failure after RT for HNSCC irrespective of HPV/p16 status. Thus, focus on predictors for the response to RT is warranted to identify patients with higher risk of high-dose failure that might benefit from intensified treatment regimens.