Temporary Stabilization Research Articles

Dominant Species Composition, Environmental Characteristics and Dynamics of Forests with Picea jezoensis Trees in Northeast China

To describe the characteristics and dynamics of the Picea jezoensis (PJ) community, a survey of 48 forest plots containing PJ trees was conducted in Northeast China. Methods of community grouping, analysis of variance, and linear regression, and indicators of relative basal area (RBA, reflecting the dominance degree of species in the community) and temporary stability (TS, reflecting the stability of forest plant community), were employed. The objectives were to describe the dominant species composition and environment of the PJ community and to quantify the changes in PJ’s dominance status. Communities with PJ trees were divided into four groups: PJ as the first dominant species; PJ as the second dominant species; PJ being co-dominant but ranked third or lower; and PJ as a non-dominant species. Among them, the PJ community (i.e., where PJ is the first dominant species) occupied sites at the highest elevation with a mean value of 1408 m, on gentle slopes ≤ 10°, where the tree species occurring with PJ mainly included Betula costata and Abies nephrolepis. A linear relationship was found between the TS and RBA. The threshold for PJ shifting between being the first and second dominant species in the community was RBA = 0.387. This study provides a scientific basis for judging the attributes and status of PJ community and the protection and restoration of PJ forests. These findings also provide comparable information for ecological research and conservation of PJ forests in other areas.

Talonavicular arthrodesis

Realignment of the hindfoot by talonavicular arthrodesis. Idiopathic and posttraumatic arthritis of the talonavicular joint with or without malalignment. Optional in flatfoot reconstruction. General medical contraindications to surgical interventions. Medial, dorsomedial, or dorsal skin incision. Exposure of the talonavicular joint and cartilage removal. Decortication. Reposition of the joint if malaligned. Optional transplantation of corticocancellous bone. Temporary stabilization with Kirschner wires and stabilization with screws, optional with cramps or plates. Sixweeks nonweightbearing in along walker boot. Afterwards 2weeks of progressively weight bearing in along walker boot. Then full weightbearing in walking shoes with stiff soles. Physiotherapy. Atotal of 18feet in 18patients with isolated talonavicular arthritis were treated with isolated talonavicular fusion and corticocancellous bone thorough amidline incision. For postoperative management, patients had nonweightbearing for 6weeks in along walker boot. Mean follow-up was 14.5months (range 8-35months). Mean age was 63.2years (range 54-72years). Preoperative Manchester-Oxford Foot Questionnaire (MOXFQ) score was 65.3 (± 5.2); postoperative MOXFQ score was 28.5 (± 7.0). One revision surgery performed due to pseudarthrosis.

Abstract 4134712: Pheochromocytoma-Induced Cardiomyopathy Requiring Mechanical Support with Ejection Fracture Recovery Following Surgical Resection

Introduction: Pheochromocytomas are catecholamine-secreting tumors that arise from chromaffin cells of the adrenal medulla. The annual incidence is approximately 0.8 per 100,000 persons, though this is an underestimate given a high percentage diagnosed at autopsy. Classically, patients present with episodic headache, sweating, and tachycardia, however, pheochromocytomas can be associated with cardiomyopathy secondary to the catecholamine excess. We present an unusual case of pheochromocytoma-induced cardiogenic shock highlighting an excellent use of mechanical circulatory support with Impella and Extracorporeal Membrane Oxygenation (ECMO) bridging to surgical intervention resulting in left ventricular ejection fraction (LVEF) recovery. Case Description: A 49-year-old female with past medical history of asthma initially presented to an outside hospital for palpitations, chest pain, and hypertension. Transthoracic echo (TTE) showed preserved left ventricle ejection fraction (LVEF) while cardiac MRI showed a LVEF of 43% with dilated left ventricle and diffuse global hypokinesis consistent with a dilated cardiomyopathy. She underwent a coronary angiogram demonstrating nonobstructive CAD. She was then discharged with readmission a month later at our hospital for chest tightness, palpitations, vomiting, weakness, and dizziness. Repeat TTE showed a drop in LVEF to 10-15%. She progressed to cardiogenic shock requiring BiPAP and inotrope initiation, with progressive shock and hypotension ultimately requiring Impella 5.5 and venoartrial ECMO. Abdominal imaging was notable for 4.7 x 4.2 cm right adrenal nodule and further workup with serum and urine metanephrines confirmed pheochromocytoma. While supported, the patient underwent right adrenalectomy with subsequent wean of mechanical circulatory support and biventricular recovery on TTE. Discussion: Pheochromocytoma-induced heart failure is a rare but potentially life-threatening complication from excess catecholamine effects on the myocardium. Pheochromocytomas should be considered in the evaluation of idiopathic heart failure even in the absence of symptoms related to catecholamine excess. Early detection, pharmacological management, and surgical resection may prevent progression of myocardial remodeling. Mechanical circulatory support can be a valuable adjunct in managing refractory heart failure in these patients by providing temporary hemodynamic stabilization while awaiting definitive tumor resection.

Construction engineering to transform the composite frame of YY London

As part of the first phase of London’s Canary Wharf redevelopment, 30 South Colonnade was a 13-storey composite framed office building completed in the early 1990s. Between 2020 and 2023 it was refurbished to become YY London, a highly sustainable modern workspace. A key aspect of the project was retention and reuse of much of the existing structure, dramatically reducing the new development’s Embodied Carbon Dioxide equivalent (embodied CO2e) impact. This paper describes the way the composite steel-framed building’s original structural configuration was developed to accommodate the move to on-screen share trading in the 1980s. It then outlines the reasons why that change was needed for the 2020s. A key feature of the construction engineering was a demolition that disconnected several bays of the original bracing from the surrounding slab, requiring staged construction of temporary stability, and complicated by an unusual decision by the original designers. UN Sustainable Development Goal 12 (Responsible consumption and production) is stimulating architect, engineers and clients to propose more extensive reuse of structures and their embodied CO2e. This paper describes the construction engineering challenges that these schemes generate for contracting teams, and some of the solutions that can be implemented to preserve and reuse the embodied CO2e of composite buildings.

Biomechanical validation of the field-expedient pelvic splint

IntroductionMorbidity and mortality from pelvic ring injuries can be mitigated by early and effective external pelvic stabilisation. The field-expedient pelvic splint (FEPS) is a recently described technique to improvise an...

Glacier Cover Estimation: a Multitemporal Retrospective Analysis of the Uruashraju Snow-capped Mountain (Ancash)

Objectives: To estimate the evolution of the glacier cover of the Uruashraju snow-capped mountain (Áncash, Peru) between the years 2014 and 2024, Theoretical framework: The research is framed in the context of climate change, specifically in the reduction of tropical glaciers. Andean glaciers are key indicators of global warming, and their retreat affects the availability of water resources, impacting sectors such as agriculture, human consumption and local biodiversity. Method: A cartographic analysis of satellite images obtained through the "Landsat 8-9 OLI/TIRS C2 L2" mission for the years 2014, 2016, 2018, 2020, 2022 and 2024 was used. The images were downloaded from the USGS Earth Explorer platform and selected from the months of July to maintain temporal homogeneity. The spatial resolution used was 30 meters in visible, near infrared (NIR) and shortwave infrared (SWIR) bands. Results and discussion: The results reveal a significant reduction of 37.28% in the glacier surface of the Uruashraju snow-capped mountain between 2014 and 2024. Despite some periods of temporary stabilization, the general trend is one of retreat due to climate change. This phenomenon affects water availability and poses risks for essential activities such as agriculture. Implications of the research: The research highlights the urgent need to take measures to mitigate the effects of climate change on Andean glaciers, since their loss compromises the water and economic security of local communities that depend on glacial resources. Originality/Value: This study offers a detailed and updated analysis of the evolution of glacier cover on the Uruashraju snow-capped mountain, providing relevant data for water resource planning and climate change adaptation strategies in the Andean region.

Leukemic occult infiltrative optic neuropathy presenting as optic neuritis: a case report

Isolated ocular relapses of leukemia are rare and typically present as infiltrative lesions of the optic nerve. This report presents a case of an isolated ocular relapse of leukemia in a female patient, characterized by occult infiltrative optic neuropathy. Despite the absence of leukemic cell infiltration on MRI, a 33-year-old female patient presented with optic neuritis, which resolved after intrathecal administration of chemotherapeutic agents. However, due to her non-compliance with the treatment regimen, leukemia progressed to infiltrative optic neuropathy. She refused radiation therapy, and while intrathecal injections provided temporary stabilization, they were insufficient for sustained disease control. This case uniquely documents the extended progression of an isolated ocular relapse of leukemia, evolving from an occult infiltrative lesion initially presenting as optic neuritis to a more pronounced infiltrative lesion. It suggests that leukemic optic nerve infiltration can occur in patients with leukemia even in the absence of MRI-detectable abnormalities. Radiation therapy emerges as a critical modality in the management of infiltrative lesions of the optic nerve.

Vascularized medial femoral condyle bone graft for the management of an acute talar neck fracture: A case report

Background Management of talar neck fractures can be challenging due to the high rate of non- or malunion, avascular necrosis and post-traumatic arthritis, which has been attributed to the disruption of the bone’s tenuous blood supply during fracture displacement. Osseous medial femoral condyle (MFC) flaps are increasingly being used in the reconstruction of small bony defects due to recalcitrant non-union and avascular necrosis in the upper and lower limbs. We report a rare case of an MFC flap used in the reconstruction of an acute talar neck fracture. Case Presentation A 38-year-old male presented with multiple injuries following a motor vehicle accident, including an open comminuted talar neck and lateral process fracture, with dislocation of the subtalar and talocrural joints (Hawkins III). Initial exploration and debridement demonstrated a significant defect in the dorsal portion of the talar neck. Temporary stabilisation was achieved with Kirschner wires and the defect was packed with bone cement. Two weeks later, a MFC flap was harvested from the ipsilateral knee and tailored to fit the talar defect. Fixation was achieved with cannulated compression screws. At six weeks post-operative, all wounds had healed, a radiograph demonstrated a positive Hawkins sign and computed tomography showed incorporation of the flap. The patient had no donor site morbidity, and commenced weight bearing at 3 months postoperatively. Conclusion This is the first report demonstrating the viability of MFC flap reconstruction for the management of bony defects in acute talar neck fractures.

Buoyancy regulation in insects.

Multiple insect lineages have successfully reinvaded the aquatic environment, evolving to complete either part or all of their life cycle submerged in water. While these insects vary in their reliance on atmospheric oxygen, with many having the ability to extract dissolved oxygen directly from the water, all retain an internal air-filled respiratory system, their tracheal system, due to their terrestrial origins. However, carrying air within their tracheal system, and even augmenting this volume with additional air bubbles carried on their body, dramatically increases their buoyancy which can make it challenging to remain submerged. But by manipulating this air volume a few aquatic insects can deliberately alter or regulate their position in the water column. Unlike cephalopods and teleost fish that control the volume of gas within their hydrostatic organs by either using osmosis to pull liquid from a rigid chamber or secreting oxygen at high pressure to inflate a flexible chamber, insects have evolved hydrostatic control mechanisms that rely either on the temporary stabilization of a compressible air-bubble volume using O2 unloaded from hemoglobin, or the mechanical expansion and contraction of a gas-filled volume with rigid, gas-permeable walls. The ability to increase their buoyancy while submerged separates aquatic insects from the buoyancy compensation achieved by other air-breathing aquatic animals which also use air within their respiratory systems to offset their submerged weight. The mechanisms they have evolved to achieve this are unique and provide new insights into the function and evolution of mechanochemical systems.

Mechanical Circulatory Support in Cardiogenic Shock: A Narrative Review.

Cardiogenic shock (CS) remains a critical condition with high mortality rates, often arising from acute myocardial infarction and advanced heart failure. Despite advancements in medical therapy, traditional interventions frequently fall short of reversing the profound hemodynamic instability seen in CS. Mechanical circulatory support (MCS) devices have emerged as crucial therapeutic options, offering temporary stabilization and bridging to recovery, heart transplantation, or long-term ventricular assist device implantation. This narrative review explores the current landscape of MCS in CS, highlighting the various types of support devices, including intra-aortic balloon pumps (IABP), veno-arterial extracorporeal membrane oxygenation (VA-ECMO), and percutaneous ventricular assist devices (pVADs) such as Impella and TandemHeart. We examine their mechanisms of action, clinical indications, and outcomes alongside the challenges and complications associated with their use. Additionally, we discuss the evolving guidelines and the role of MCS in contemporary CS management, emphasizing the need for timely intervention and a multidisciplinary approach. The review underscores the importance of individualized patient selection and device choice to optimize outcomes in this critically ill population.

SP3.10 - Utilisation and Outcomes of Emergency Laparoscopic Resection for Colon Cancer: A Population-based Study in England

Abstract Aims To evaluate the current use and outcomes of urgent or emergency laparoscopic resection of colon cancer in the National Health Service in England. Methods 11,182 patients from the National Bowel Cancer Audit diagnosed with colon cancer from April 2017 to March 2022 in England, who underwent urgent or emergency resection, were included. Multivariable logistic and linear regression was used to quantify factors associated with use of laparoscopic surgery and compare risk-adjusted postoperative outcomes between laparoscopic and open surgery. Results The use of emergency laparoscopic resection increased from 33.0% in 2017 to 47.5% in 2022, with a temporary stabilisation during the first wave of the COVID-19 pandemic (38.9% 2020/21). In risk-adjusted analyses of 9,579 patients, patients with poorer physical status [ASA 4/5 vs 1, aOR 0.35 (95% confidence interval 0.27-0.44) P < 0.001], more advanced T-stage [T4 vs T1-T2, aOR 0.26 (0.21-0.32) P < 0.001] and M-stage [M1 vs M0, aOR 0.87 (0.76-0.99) P < 0.036] were less likely to undergo laparoscopic surgery. No association was found with age, socioeconomic deprivation, or nodal stage. Patients undergoing laparoscopic resection had a shorter length of stay [adjusted mean difference -2.55 days (-3.23, -1.87), P < 0.001], lower 90-day mortality [aOR 0.75 (0.63-0.89), P = 0.001], and lower 30-day unplanned reoperation [aOR 0.82 (0.70-0.96), P = 0.014] than patients undergoing open resection. Conclusion There has been an increased utilisation of laparoscopic surgery in the emergency setting, and it is associated with reduced hospital stay, postoperative mortality and unplanned reoperation.

Treatment of rotational tibial malunion after minimal invasive plate osteosynthesis (MIPO): Corrective osteotomy with original plate retention (PR-Osteotomy)

Background and purposeResidual axial and rotational deformities in tibial shaft fracture, after minimally invasive osteosynthesis (MIO) treatment, are widely described in literature. Nevertheless, there is still a lack of evidence about the malunion treatment strategies and results. The aim of our study is to present an innovative technique for tibial shaft malunion: a derotational proximal tibial osteotomy without removing the original plate (Plate-Retaining-Osteotomy: PR-Osteotomy). Materials and methodsWe present the results of two consecutive patients’ treatment, affected by tibial shaft fracture malunion, as sequelae of MIO treatment. The two patients, male 60 years old and female 39 years old, underwent previous surgical treatment with an average of 9 months span time before surgical revision. The affected limb showed significant external torsional defect associated with gait impairment, pain and limping. The amount of rotational deformity and the bone healing condition is assessed through a methodical preoperative planning, including weight bearing lower limbs Xray and bilateral computed tomography (CT) scan of the lower limbs. The surgical technique involves a monoplanar tibial osteotomy, in a perpendicular fashion to the tibial axis, at a level that would allow at least 3 proximal screw-holes to become available for subsequent fixation. Proximal to the osteotomy line the screws are removed, while the distal ones, if stable after testing, are left in place. The amount of torsional correction, planned on CT, is reproduced intraoperatively with the assistance of graduated templates. A fibular osteotomy may be performed if required. After temporary stabilization, the correct functional reduction is checked with the aid of fluoroscopy and empirical rod measurement, using the contralateral limb alignment as a reference. Once the desired correction is achieved, absolute stability is applied to the osteotomy site. Postoperative rehabilitation protocol involves partial weight bearing for 6–8 weeks with progression to full weight bearing by 10–12 weeks. ResultsBoth patients showed complete osteotomy healing at the 13th and 16th week respectively, with no complications and full recovery of normal gait and daily life activities. ConclusionsTo our knowledge, this is the first description of such surgical technique. Less invasiveness, fast recovery time and cost reductions are the foremost proposed benefits. Further larger case series with longer follow up are needed to assess the advantages of the proposed treatment strategy.

Staged Management for Distal Femur Fractures: Impacts on Reoperation, Stiffness, and Overall Outcomes.

To evaluate the outcomes of staged management with external fixation (ex-fix) prior to definitive fixation of distal femur fractures. Design: Retrospective cohort. Single Level I Trauma Center. Adults treated operatively between 2004 and 2019 for distal femur fractures (OTA/AO 33A/33C) were identified using Current Procedural Terminology codes. Excluded cases were those with screw only fixation, acute distal femur replacement, 33B fracture pattern, no radiographs available, or did not have 6-months of follow-up. Postoperative complication rates including surgical site infection [SSI], reoperation to promote bone healing, final knee arc of motion <90 degrees, heterotopic ossification formation, and reoperation for stiffness were compared between patients treated with ex-fix prior to definitive fixation and those not requiring ex-fix. A total of 407 patients were included with a mean follow-up of 27 months (median [IQR] of 12 [7,33] months), (range 6-192 months). Most patients were male (52%) with an average age of 48 [Range: 18-92] years. Ex-fix was utilized in 150 (37%) cases and 257 (63%) cases underwent primary definitive fixation. There was no difference in SSI rates (p=0.12), final knee arc of motion <90 degrees (p=0.51), and reoperation for stiffness (p=0.41) between the ex-fix and no ex-fix groups. The 150 patients requiring ex-fix spent an average of 4.2 days (SD 3.3) in the ex-fix before definitive fixation. These patients were further analyzed by comparing the duration of time spent in ex-fix, <4 days (n=82) and ≥4 days (n=68). Despite longer time spent in ex-fix prior to definitive fixation, there was again no significant difference in any of the complication and reoperation rates when comparing the two groups, including final knee arc of motion <90 degrees (p=0.63), reoperation for stiffness (p=1.00), and SSI (p=0.79). Ex-fix of distal femur fractures as a means of temporary stabilization prior to definitive ORIF does not increase the risk of complications such as SSI, final knee arc of motion <90 degrees, or reoperations for bone healing or stiffness when compared to single stage ORIF of distal femur fractures. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Theory of Projection

Abstract Whitehead’s process philosophy offers a wide range of speculatively generalized concepts that allow for an application in transdisciplinary research. The notion of projection is an often-overlooked detail of his philosophy that not only appears in his far-reaching theory of perception, but also constitutes an integral part of his theory of extension as the formal foundation of his metaphysical project. His perceptive theory relies on the idea of projection as the fundamental ontological relationship that lifts the past into the present. Projections of sensa describe one side of the ‘double-barreled’ theory of perception and the spatial relations of the contemporary world. The microscopic projection is just as fundamental for perception and for the integrity of a relational theory of becoming, as the perceptual projection is necessary ingredient for symbolic modes of experience. The simple projection in the mode of presentational immediacy is the basis of temporary stability of events and of any perceptual situation in the biological realm. Whitehead was aware of the possible misconceptions that this term might lead to. Discussing his remarks on the hierarchical variety of different modes of projection can resolve those misconceptions and throw a new light on the importance of projection for interdisciplinary inquiries.

Management of infected bone defects of the femoral shaft by Masquelet technique: sequential internal fixation and nail with plate augmentation

BackgroundTo evaluate the effectiveness of a sequential internal fixation strategy and intramedullary nailing with plate augmentation (IMN/PA) for bone reconstruction in the management of infected femoral shaft defects using the Masquelet technique.MethodsWe performed a retrospective descriptive cohort study of 21 patients (mean age, 36.4 years) with infected bone defects of the femoral shaft treated by the Masquelet technique with a minimum follow-up of 18 months after second stage. After aggressive debridement, temporary stabilisation (T1) was achieved by an antibiotic-loaded bone cement spacer and internal fixation with a bone cement–coated locking plate. At second stage (T2), the spacer and the locking plate were removed following re-debridement, and IMN/PA was used as definitive fixation together with bone grafting. We evaluated the following clinical outcomes: infection recurrence, bone union time, complications, and the affected limb’s knee joint function.ResultsThe median and quartiles of bone defect length was 7 (4.75–9.5) cm. Four patients required iterative debridement for infection recurrence after T1. The median of interval between T1 and T2 was 10 (9–19) weeks. At a median follow-up of 22 (20–27.5) months, none of the patients experienced recurrence of infection. Bone union was achieved at 7 (6–8.5) months in all patients, with one patient experiencing delayed union at the distal end of bone defect due to screws loosening. At the last follow-up, the median of flexion ROM of the knee joint was 120 (105–120.0)°.ConclusionsFor infected femoral shaft bone defects treated by the Masquelet technique, sequential internal fixation and IMN/PA for the reconstruction can provide excellent mechanical stability, which is beneficial for early functional exercise and bone union, and does not increase the rate of infection recurrence.

Load-bearing furniture modules for fast deployable and reusable systems

The urgent need to reduce carbon emissions in the construction sector has driven the exploration of circular economy practices in the built environment. Nevertheless, the implementation of circular economy principles in projects remains limited. This research contributes to bridging this gap by introducing a project proposal that establishes a typology of modular systems designed for easy assembly, disassembly, and reuse. Specifically, the proposal focuses on load-bearing wood furniture modules (FMs) as an intermediate solution between planar and volumetric modules. These FMs expand the structural wall’s volume, facilitating the integration of services, storage, and appliances. This addresses scenarios where swift building deployment is required. The proposed modular dimension enhances transportation efficiency compared to volumetric solutions and simplifies construction by eliminating the need for temporary stabilization, as seen in planar systems. Standardization and “separability” of each component within the FM allows for easy integration and maintenance. Special attention is paid to the timber connection systems within and between FMs facilitating easy assembly, and disassembly for future reuse. The adaptability of the FM concept is demonstrated through versatile compositions and layouts, facilitating space reconfiguration. While the technical feasibility of the FM-based system is demonstrated, further research is needed to address regional and cultural variations and customize the system to different contexts. The study emphasizes the potential of FMs as a solution for buildings aligned with circular economy principles and highlights the importance of continued research and development in this field.

Research on the geological process of river action on the toppling deformation of rocky bank slopes in V-shaped gorge reservoirs

The toppling deformation in bank slope of V-shaped Gorge reservoirs in Southwest China is very common. After the impoundment of the reservoir, geological disasters such as collapse and landslide may occur in toppling bank slope, which poses a threat to the normal operation of hydropower projects and personnel safety. Therefore, it is of great engineering significance to study its genetic mechanism and development law. The trenching of river valley is one of the main factors of bank slope toppling deformation. In the process of river action, the free face is formed on the slope, and the rock mass is unloaded to the free face, resulting in toppling. Taking the bank slope of a reservoir in the V-shaped Gorge area on the edge of the Qinghai Tibet Plateau in Southwest China as an example, this paper studies the relationship between river action and the development of toppling. According to the seven terraces formed on both banks of the river, the trenching of the river valley is divided into seven stages. The toppling development characteristics of each stage are analyzed by discrete element method. According to the development characteristics of toppling deformation category, the toppling deformation is divided into five stages, they are initial toppling deformation stage, toppling development stage, intensified toppling deformation stage, temporary stability stage and failure stage. The research results can help to determine the development type and stage of bank slope toppling deformation in V-shaped Gorge area, so as to predict its further development deformation characteristics.

Finite element analysis of reconstruction plates in mandibular defects

Segmental defects in the mandibular bone can occur after local trauma, infection, or surgical resection. Several reconstructive possibilities are currently available, and temporary stabilization of bone segments with reconstruction plates is commonly used when immediate bone reconstruction is not possible. However, little attention has been paid to the biomechanical aspects involved in this approach, and studies conducted with biomodels face the difficulty of simulating the muscular forces involved. The use of Finite Element Analysis allows for the mathematical evaluation of structures in a controlled environment, applying forces at any point and/or direction, assessing material deformation, as well as the tension applied to them. Thus, the aim of this study was to evaluate reconstruction plates used on segmental defects through mathematical analysis using finite elements. After simulation, lower stress values were found on thicker plates, suggesting greater resistance to fracture. Conversely, significantly increased stress values on the screws were present in thicker plates.

M‐AGC tangent visco‐plastic operator with hardening/softening, and application to the visco‐plastic relaxation analysis of stable and unstable problems using fracture‐based geomechanical interfaces

AbstractA previous perfect visco‐plastic constitutive formulation of the Perzyna type incorporating the concepts of prescribed stress increments and m‐AGC tangent operator (m‐Assumed algorithmic generalized compliance tangent operator) is extended to the case of Hardening/Softening (H/S). This extension is possible thanks to the closed‐form solution developed for the evolution of the loading function during a visco‐plastic time step. The formulation is then applied to constitutive modeling of zero‐thickness interfaces on the basis of a well‐established fracture‐based elasto‐plastic formulation, which in this manner is extended to visco‐plasticity. The resulting model is implemented in the finite element (FE) and small‐strain context by using both a standard Newton Raphson scheme for physical visco‐plasticity in which visco‐plastic time corresponds to physical time, and a Visco‐Plastic Relaxation (VPR) scheme, in which time corresponds to a fictitious time governing the transition from the elastic to the inviscid elasto‐plastic response. The numerical implementation is verified satisfactorily for common loading cases at interfaces such as pure tension (mode I) opening and shear‐compression (mixed‐mode) cracking/sliding, showing that the visco‐plastic results match the predictions of the fracture mechanics inviscid model in the long term. In addition, it is also shown that the VPR strategy developed is capable of providing temporary stability while the equilibrium path is recovered during instability events such as a snap‐back in the load‐displacement curve. This feature opens the door to a number of potential advanced applications of the formulation developed in the geomechanical context.

Evidence in Practice: How Structural and Programmatic Scaffolds Enable Collaboration in International Development

This inductive study of eight international development interventions analyzes mechanisms that enable integration of evidence in practice, a perennial challenge of learning and collaboration across occupational and organizational boundaries. We demonstrate how structural and programmatic scaffolding practices enabled actors from an array of organizations and communities of practice to collaborate and learn despite the uncertainty and complexity inherent in the international development context. These modular scaffolding practices offered temporary stabilization and support that fostered the counter-normative behaviors and mindsets required for continuous learning and adaptive coordination. Through 226 in-depth interviews with international development experts, including practitioners in eight matched interventions in India, Mexico, South Africa, and Ghana, we identified and analyzed mechanisms that explain the varying effectiveness with which evidence was integrated in each case. Our findings have implications for interorganizational innovation and collaboration under conditions of complexity and uncertainty and for dynamic interactions among individuals, their organizations, and their communities of practice when they are attempting to bring about systemic change.