bluuebunny/crossref_metadata_2025 huggingface dataset:
“It’s All Closer and More Personal to Me”: The Meaning of Closeness for Migration-Related Civic Engagement of Czech Adolescents
Authors: Rapoš Božič Ivana , Kotýnek Krotký Jan
Published: September 2024

The lack of trust in politics and poor civic engagement challenge both new and established democracies. To tackle this challenge, it is necessary to understand what motivates new generations of citizens to become civically engaged. We contribute to discussions about this issue by offering a qualitative, in-depth exploration of adolescents’ motivations for civic engagement, focusing specifically on the issue of migration. Drawing on data from four critical focus groups conducted with adolescents (17–19 years old) in Czechia, we ask how their perspectives on migration translate into motivation for migration-related civic engagement. Utilizing the theoretical perspective and interpretative approach of cultural sociology, we look for the meanings that sustain their personal motivation to become engaged. We find that feelings of closeness to the issue of migration act as an essential driver of adolescents’ personal motivation for engagement, making migration an issue of concern to them. We further distinguish between cultural closeness and closeness of contact and identify distinct mechanisms through which these forms of closeness translate into adolescents’ concerns about the issue of migration. Based on our findings, we call for greater consideration of the role of culture and local context in the research on adolescents’ motivations for civic engagement.
Leadership matters: The role of destructive leadership behavior and teachers’ demographic characteristics on teachers’ social engagement with students
Authors: Anteneh Atalay Mesfin , Gebremeskel Melaku Mengistu
Published: September 2024

The study intended to investigate the role of destructive leadership behavior, and teachers’ demographic characteristics on teachers’ social engagement with students in colleges of teacher education in the State of Amhara. A mixed method with an explanatory sequential design was employed. 397 teachers and 366 students participated in the quantitative data collection (questionnaire), whereas the qualitative data were collected with the help of interviews with college deans and teachers. Data collected through a questionnaire was analyzed through descriptive and inferential statistics. On the other hand, narration and interpretation were employed for qualitative data analysis. Findings revealed that deans’ destructive leadership behavior was exhibited significantly. Teachers were socially engaged with students (t (396) = 58.902, d = 0.54, p = .000). Deans’ destructive leadership behavior and demographic characteristics explain teachers’ social engagement with students. However, demographic characteristics only have a minimal contribution in explaining teachers’ social engagement with students. In conclusion, demographic characteristics have no role in teachers’ social engagement with students but destructive leadership behavior plays a role. Finally, recommendations were forwarded to potential stakeholders.
The Relationship Between Course Structure and Intensity, and Student Success in Developmental Education
Authors: Park-Gaghan Toby J , Mokher Christine G.
Published: September 2024

Texas legislation mandated that colleges offer developmental education using a corequisite model, where students concurrently enroll in introductory college-level courses with supplemental developmental support. Using data from the population of Texas students in developmental education, we estimated regression models to investigate differential relationships between corequisite characteristics and outcomes, both overall and by student characteristics. Our findings suggest there is no single “magic bullet” course structure that is universally more effective, as relationships between the reform and student success vary by subject and student subgroup. Additionally, even a single credit of corequisite developmental support can be beneficial for some students, potentially more so than traditional three-credit courses.
Oral and Dental Pain Management
Authors: Mathis Jennifer , Schilling Elizabeth , Lobprise Heidi
Published: September 2024

Pain has been defined as an unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage. Pets often experience the same pain as people; however, dental pain is often overlooked, discounted, or unseen/hidden in patients, as the inability to communicate does not negate the possibility that a human or a nonhuman animal experiences pain. This article discusses types of pain and the methods and medications available to treat and prevent oral pain.
De-centring inclusion: Discussing the meaning and place of inclusive education in international and European law through the case of children with autism
Authors: Ducarre Lucie Margot
Published: September 2024

This paper aims to contribute to the current legal reflections on the meaning and place of inclusive education within the conception of the right to education. While the recent progress on inclusive education have contributed to enhance the realisation of the right to education for many disabled children, it has had mixed results for others. Autistic children in particular appear to still suffer from poor educational experience and outcomes. This paper argues that better fulfilling the right to education of autistic children will entail abandoning the conception of inclusive education as exclusively realised in mainstream schools. Instead, it appears important to offer a variety of settings and to refocus the discussions on the notions of non-discrimination and substantial equality, quality education, and children's rights.
Strategic alliances and global competitive actions: Unveiling collaborative pathways in higher education ranking
Authors: Izharuddin Muhammad , Sukoco Badri Munir
Published: September 2024

The escalating competition among higher education institutions in global university rankings necessitates an examination of their actions and reactions within a competitive dynamics framework. Utilising regression panel data, this study scrutinises the initiatives of 100 universities across 22 Asian nations over a decade, drawing from the QS World University Rankings and SciVal databases. Exposure, research intensity, and high-impacted research are identified as drivers of competition escalation. Moreover, the impact of international collaboration and university-industry collaboration on this dynamic is analysed, revealing varied moderating effects. By delving into the influence of international academic collaboration and university-industry collaboration, this research unveils opportunities for adopting a cooperative-competitive strategy among universities to excel in global ranking competitions.
Ethnopsychology in the Bismarck Archipelago: Richard Thurnwald and the visual anthropology of German colonialism
Authors: Vollgraff Matthew
Published: September 2024

Between 1906 and 1909, the Austrian-born German anthropologist Richard Thurnwald undertook an expedition to Germany's Pacific colonies on behalf of the Berlin Museum for Ethnology. There he carried out a series of experimental psychological tests to investigate the mentalities and intelligence of Melanesian subjects. Due to the limitations on verbal communication, Thurnwald privileged non-verbal experiments, especially involving drawings made by his local assistants and guides. His 1913 publication Ethnopsychological Studies on South Seas Peoples reproduces some 200 of those images, which have seldom been studied since. This article examines Thurnwald's experiments in ethnopsychology through the lens of these visual materials and situates his project within larger international trends of scientific colonialism. Despite purporting to further native welfare, his application of experimental psychology to the colonial field was meant to provide solutions to the administration's most urgent problems: pacification, labour recruitment, and a declining birth rate. Yet, as this article argues, the images he collected can also be read against the grain as documents of indigenous response to German colonial rule.
Study on contact characteristics of double-disk arc-contact lapping for cylindrical rollers based on influence coefficient method
Authors: Wei Changxu , He Chunlei , Chen Guang , Su Yongxiang , Sun Yongquan , Tan Helong , Ren Chengzu
Published: September 2024

The double-disk arc-contact lapping (DDACL) method is a novel for precision machining of the rolling surface of cylindrical roller. The contact characteristics of DDACL process can affect the lapping quality of the bearing roller. However, there is a limited amount of study on the contact theory of DDACL. Therefore, the objective of this research is to create a semi-analytical modeling approach that can effectively and accurately forecast the contact characteristics of DDACL. In the initial step, the spatial coordinate transformation was employed to establish accurate mathematical models that represents the surfaces of the cylindrical roller and arc groove. Subsequently, the potential contact area was determined and subdivided into discrete elements based on the differential geometry principles. The accurate flexibility of the potential contact area is achieved by utilizing the interpolation theory and considering both the global and local deformations of the roller and groove. By employing the influence coefficient method and the force-deformation coordination relation, the deformation and contact force can be calculated. Finally, the accuracy and efficiency of this calculation is confirmed through a comparison between the finite element method (FEM) and the proposed method.
3E investigation on novel ORC-ERC system suitable for low temperature applications
Authors: Omprakash M. , Mahendiran S. , Ganesh N. Shankar
Published: September 2024

Combined cooling and power generation have gained significant attention due to their improved input energy utilization compared to standalone power cycles. The novel system combines an ejector refrigeration cycle (ERC) with the Organic Rankine cycle (ORC). The ORC-ERC system uses three heater configurations to heat the working fluid, utilizing waste heat from the ORC turbine exhaust, the ejector, and engine waste heat. The parameters to be evaluated are the hot source temperature and the turbine inlet pressure (TIP). As the temperature of the heat source and the pressure of the turbine inlet increase, the energy efficiency of the power production system also increases, but the net output and energy efficiency decrease. At 145 °C heat source temperature and 19 bar pressure at the turbine inlet, maximum output is reported. The ERC system has resulted in net work and energy efficiency of 254.6 kW and 12.38% at 24 bar TIP. Whereas the exergy efficiency is reported as maximum with 56.37% at a TIP of 19 bar, The exergy destruction in the components HE2 and turbine results in 48.1 kW and 50.47 kW, respectively, at higher input conditions for the turbine. At a TIP of 24 bar, the component turbine and heat exchanger HE1 have a combined exergy destruction and capital investment cost rate of 96,111.77 and 7861 $/Yr., respectively. Among the other components, the endogenous and exogenous exergy for the turbine results were high, with 38.23 kW and 7.67 kW, respectively. The exergy destruction for the HE2, turbine, and ejector, with respective values of 45.9, 38.2, and 18.28 kW, influences the exergoenvironmental effect rate. The present study reports a total exergoenvironmental impact rate of 3241.62 mPts/hr at a TIP of 24 bar.
Optimising the quality of several welds in a metal-inert gas arc joining of AA6082 and AA7075 using the grey-based Taguchi technique
Authors: Kumar Vinay , Vipin  , Mishra RS
Published: September 2024

In recent times, welding procedures have become increasingly crucial for fabrication and manufacturing businesses. Gas metal arc welding, also known as metal inert gas (MIG) welding, has attracted much attention because of its versatility. Its benefits include low capital needs, high deposition rates, high productivity, and simplicity in adjusting to automation. It has drawn much interest because of its versatility in welding metallic materials and ease of automation. This work's objective is to maximise the multi-performance properties of the aluminium alloys AA6082 and AA7075's MIG-welded butt junction by using a hybrid grey-based Taguchi technique. During MIG welding, With the L9 Taguchi orthogonal array, the welding speed, gas flow rate, and current were optimised. Weld joint integrity has been evaluated using the fusion zone's Vickers microhardness, per cent elongation, tensile strength, and yield strength. The ideal welding current for the MIG process is 140 A, the perfect welding speed is 10 mm/min, and the excellent gas flow rate is 18 lit/min. The material showed 159.68 MPa of tensile strength, 112.79 MPa of yield strength, 16.79% of percentage elongation, and 70.95 HV of hardness under optimal conditions. With a 63.99% contribution to the process, welding speed greatly affected the weldments' overall performance. The confirmatory test confirmed the optimisation procedure also demonstrated that optimising numerous welded joint performance factors may be achieved effectively with the grey-based Taguchi approach.
Flow characteristics and factors affecting flow pulsation of external meshing herringbone gear pump
Authors: Yang Jinlong , Lee Chul-Hee
Published: September 2024

To enhance the outlet flow stability of the external herringbone gear pump, an analysis was conducted on the main influencing factors, key geometric parameters were identified, and a numerical model was developed for fluid analysis. A numerical model was then established for fluid analysis. The accuracy of the numerical model was verified by comparing it with experimental results, with simulation errors of displacement and volumetric efficiency being < 5%, ensuring the simulation's accuracy. The simulation results indicated that the pump's head (49.7808 m) and outlet pressure (4.9285 bar) remained stable. At 700 rev/min, the simulated volumetric efficiency was 82.94%. Subsequently, the impact of helix angle, changes in center distance, and tip clearance on outlet flow stability were analyzed. The analysis revealed that increasing the helix angle from 27° to 30° could reduce flow pulsation. A slight reduction in center distance from 180.3 (δ = +0.3 mm) to 179.9 mm (δ = −0.1 mm) effectively decreased mass flow difference and outlet pressure pulsation, enhancing outlet output stability. Reducing tip clearance from 0.25 to 0.12 mm, while meeting design requirements, resulted in more stable pressure and lift output. These results ensured smooth pump operation, improved outlet output stability, and met low-flow pulsation requirements. This study offered valuable insights into the design and production of the external meshing herringbone gear pump.
Evaluation of electric vehicle power routing and charging analysis using artificial neural network synchronized with 5G-network
Authors: Anand M , Pandian S Chenthur , Kalaiselvi P
Published: September 2024

To motivate the advanced National Clean Air Program (NCAP) strategy announced by the Indian Government in 2017, automizing the routing control on electric vehicle (EV) is a challenging area. According to the public authority guideline, the air contamination issues over the nation focus on accomplishing a 20% to 30% decrease in vehicular outflows in 2024 by enhancing EV mobility. However electric vehicle's limitations on battery capacity and route strategy to charging stations to preserve an adequate level of battery charge still need automized communication strategy. Fixed route solutions might not always be executable because battery consumption varies on several external factors. To better fit the real situation, this study proposes the notion of breaking down the self-adaptive online routing by encountering automatic path detection concerning battery efficiency with adaptive charging decisions. An inventory control-style charging technique is suggested to account for stochastic battery use. In the proposed work, by using an artificial neural network, the power demand and energy consumption of the EV world will be monitored and controlled by using 5G coverage on the smart city evolution. The obtained simulation analysis confirms that in comparison to current conventional and fixed tariff schemes, 5G accompanied EV accomplish an examined rate of SoC charge around 19.95 MW holding a peak range of 108.96 MW. Also, an evaluated typical power loss rate of 2.873 kWH which is less than 11.95% through frequency band analysis with signal-to-noise ratio and downlink power utilization.
British Association of Sexual Health and HIV (BASHH) UK guidelines for the management of syphilis in pregnancy and children 2024
Authors: Kingston Margaret , Wilson Janet , Dermont Sarah , Fifer Helen , Chan Koon , Lyall Hermione , McMaster Paddy , Shawkat Emma , Thomas-Leech Alex
Published: September 2024

This new guideline details the specific management of syphilis in pregnancy and in children. It is to be used in clinical practice alongside the BASHH UK guidelines for the management of syphilis 2024.
Destigmatizing borderline personality disorder with social justice and intersectional cultural humility: How researchers can construct and deconstruct stigma
Authors: Ma Ruofan , Else-Quest Nicole M.
Published: September 2024

Borderline personality disorder (BPD) is a serious psychiatric condition, especially stigmatized in women. Stigma is a social injustice, as it discredits and reduces the wholeness of a person to one of taint and discount. Psychological scientists play a uniquely powerful role in the stigmatization and destigmatization of BPD by constructing the meaning of BPD at each step of the research process. We discuss this powerful role and how to destigmatize BPD by incorporating an intersectionality framework that includes disability as a category of difference (as with gender, race, and sexuality). This framework centers the role of systems and structures in creating and maintaining stigma, while emphasizing the close interactions between interpersonal and structural stigma. This article illustrates researchers’ power to assign meaning to BPD in research and highlights the importance of considering individuals as embedded in intersectional social categories, which are multidimensional and dynamic in nature. We propose that intersectional cultural humility, with its social justice aim and feminist origins, can guide BPD researchers to conduct nonstigmatizing and rigorous research on BPD. To inform clinical practice and advance social justice, we offer action steps for researchers to destigmatize BPD with intersectional cultural humility at multiple steps in the research process.
The Western psychologization of global development: A cultural and decolonial approach
Authors: Adolfsson Johanna Sofia , Finyiza Gertrude
Published: September 2024

Euro-American psychology’s strong focus on the individual mind and behavior has become a fundamental part of global development agendas. Concepts like self-regulation, self-actualization, self-efficacy, and behavior change decorate the development discourse. Scholars term this phenomenon the “psychologization of development.” The main driver of this focus is likely rooted in the hegemonic belief that Western psychological theories are universally applicable. Yet, the discipline’s embeddedness in Euro-American imperialism, globalization, and neoliberalism makes its theories particularly un-universal and unfit in many contexts. Nevertheless, people in non-Western societies are increasingly subjected to development interventions targeting their individual behavior. Using examples from research in sub-Saharan Africa of how articulations of harmful witchcraft may increase because of development interventions that promote individualized ways of being and thinking, this article prompts a cultural and decolonial perspective to reimagine other ways of doing development.
For Debate: Concomitant Critical Coronary Arterial Disease and Abdominal Aortic Aneurysm — Timing of Corrective Procedures
Authors: Onwudike M. , Barnard M. , Singh-Ranger R. , Raphael M. , Adiseshiah M.
Published: September 2024

Background.

The high prevalence of coronary artery disease (CAD) in patients with abdominal aortic aneurysm (AAA) is responsible for most < 30-day mortality and morbidity in elective repair of AAA. The continuing debate regarding staged or combined surgery for AAA and CAD (coronary artery bypass grafting — CABG) in the small number of patients with critical degrees of both co-morbidities has not had a significant impact on the greater mortality and morbidity when the AAA repair is undertaken using the standard open operation.

Patients.

We report four cases with these combined pathologies which we have managed over the last 30 months during which time we have developed techniques of endolumenal repair of AAA.

Conclusions.

Whilst it is not possible to make firm recommendations regarding management strategy owing mainly to a lack of large series reporting this unusual combination of co-morbidities, the options are debated on the basis of published anecdotal evidence as well as our own case reports. We suggest that if the AAA is non-tender and/or 5.5–8.0 cm, the staged approach is appropriate. If the AAA is tender and/or > 8.0 cm, a combined approach may be a better option in order to avoid the risk of AAA rupture during the interval between the operations. Endolumenal repair of AAA offers a further option for the staged and combined approach, and may be less invasive than the standard open surgery for AAA repair.
Pericapillary Fibrin Deposits and Skin Hypoxia Precede the Changes of Lipodermatosclerosis in Limbs at Increased Risk of Developing a Venous Ulcer
Authors: Stacey M.C. , Burnand K.G. , Bhogal B.S. , Black M.M.
Published: September 2024

This study investigated the possibility that pericapillary fibrin deposition, found in the calf skin of patients with venous ulceration and lipodermatosclerosis, might already be present in the dermis of the gaiter area of apparently healthy limbs before any skin changes were visible. The apparently healthy limbs of 19 consecutive patients with a healed venous ulcer on one leg and no history of ulceration or clinical evidence of lipodermatosclerosis in the opposite calf, were studied. Bipedal ascending phlebography and foot volume plethysmography were performed, and systemic fibrinolytic activity and fibrinogen levels were calculated. Transcutaneous oxygen measurements were expressed as a ratio of levels from a fixed position in the gaiter skin over a control site on the arm. Biopsies of a standard site in the gaiter skin and the thigh were assessed for the presence of laminin, fibrinogen and fibronectin using immunofluorescent microscopy. The extent of pericapillary fluorescence was expressed as a ratio of the number of capillaries with deposits divided by the total number of capillaries staining with laminin (fibrin and fibronectin scores).

Pericapillary fibrin deposits were observed in the dermis in 16 of the biopsies of the gaiter region (median score 0.20), and in eight of the biopsies from the thigh (median score 0.0). This difference was highly significant ( P < 0.01, Wilcoxon signed rank test). The transcutaneous oxygen ratio correlated negatively with the fibrin score (Spearman rank correlation coefficient − 0.62, P < 0.01), and there was a weak negative correlation between the half volume refilling time on foot volume plethysmography (an indicator of venous reflux) and the fibrin score (Speraman rank correlation coefficient − 0.47, P < 0.05). No such correlation could be shown between the fibrin score and the indicators of calf pump function, the euglobulin clot lysis time or the plasma fibrinogen. The presence of significant numbers of pericapillary fibrin deposits within the dermis of the gaiter skin has been demonstrated in 84% of this cohort of ‘at risk’ limbs before there is any evidence of clinical lipodermatosclerosis.
Lower Levels of PAI-2 May Contribute to Impaired Healing in Venous Ulcers — A Preliminary Study
Authors: Stacey Michael C. , Mata Sandy D.
Published: September 2024

Plasminogen activators may potentially influence the wound healing processes of cell migration matrix degradation and cellular adhesion in venous ulcers by their regulation of protease activity The aim of this study was to assess the levels of plasminogen activators in venous ulcers and to gain preliminary data from healing wounds.

The concentrations of u-PA, t-PA, PAI-1 and PAI-2 antigen as well as functional u-PA were assessed in tissue homogenates from 20 chronic venous ulcers, six actively healing venous ulcers and five traumatic wounds.

The concentrations of functional u-PA. u-PA antigen and PAI-1 were significantly greater and PAI-2 was siqnificantly lower in the edge and base of chronic venous ulcers compared to adjacent intact skin ( P < 0.01). Healing wounds had significantly higher functional u-PA at the ulcer edge and higher u-PA antigen concentration in intact skin ( P < 0.05). PAI-2 levels were significantly higher in the ulcer edge and base in the healing wounds than in chronic

These findings suggest that regulation of protease activity by u-PA and PAI-2 may play a role in the impaired healing of chronic venous ulcers.
Posterior Transverse Plication Technique for Treatment of Redundant Internal Carotid Artery during Endarterectomy
Authors: Ascher Enrico , Hingorani Anil , Gunduz Yilmaz , Mazzariol Fernanda , Yorkovich William , Salles-Cunha Sergio
Published: September 2024

Purpose:

Posterior transverse plication (PTP) has gained popularity as a technique to correct redundancy of the internal carotid artery during endarterectomy. The safety of this technique in large series of patients has not been extensively studied. We investigated 876 primary carotid endarterectomies (CEAs) performed at our institution over the last six years to determine the safety of this technique.

Methods:

Indication for surgery was carotid stenosis ≥ 70% in 341 (39%) symptomatic and 535 (61%) asymptomatic cases. Preoperative imaging consisted of duplex ultrasound alone or combined with magnetic resonance angiography. Patients were divided into four groups related to surgical technique: CEA + PTP + 8 mm patch (group la), CEA + PTP + 10 mm patch (group lb), CEA + patch (group II) and CEA + primary closure (group III). There were 43, 39, 581 and 213 patients in groups la, lb, II and III, respectively. No statistical differences in age, sex or risk factors for atherosclerotic disease were noted among the groups. Postoperative duplex ultrasonography was used at 2 weeks and every 6 months thereafter to evaluate the adequacy of the repair and presence of complications such as pseudoaneurysm formation and extrinsic compression by the excluded carotid segment.

Results:

The 30-day mortality was 1.2%, 0.6% and 0.3% for groups I, II and III, respectively. Stroke rates for the same period were 0%, 0.6% and 0.8% for groups I. II and III, respectively. Duplex ultrasonography demonstrated significant stenosis (≥ 50%) in two (5%) patients in group la at 12 months. No restenosis was observed in group lb. For groups II and III the rates of restenosis were 1.5% and 0.8%. One patient in group II developed a pseudoaneurysm after 7 months.

Conclusion:

Posterior transverse plication safely corrects redundancy of the internal carotid artery during endarterectomy without causing early significant restenosis. Continued follow-up in a larger group of patients to determine long-term efficacy and correlation between patch size and restenosis rate is warranted.
Comparison of the Flow Capacity of Free Arterial Grafts and Saphenous Vein Grafts for Coronary Bypass Surgery
Authors: Hall Timothy S. , Ferguson John , Sines Jean , Spotnitz Alan J.
Published: September 2024

There is controversy regarding the flow reserve and capacity of arterial conduits to meet the needs of the myocardium. This study compared flow in 22 free arterial bypasses to 15 saphenous vein grafts in procedures involving twenty patients. To assess the maximal flow possible, (flow capacity) graft flow was measured using a calibrated pump while perfusing blood cardioplegia through the conduit and distal anastomosis during cardiac arrest (no competitive flow). This assessment was subsequently confirmed with whole blood during myocardial contraction while on cardiopulmonary bypass. Twenty-two free arterial grafts were used; 15 right internal mammary artery grafts. 4 right gastroepiploic grafts. 3 inferior epigastric artery grafts, and 3 sequential bypasses. Free arterial conduit flow ranged from 50 to 180 cc/ml, with an average flow of 102.5 ± 28.5 ml/min as compared to saphenous vein graft flow. 102 ± 28 ml/min. No correlation of flow with the conduit size was found. Arterial graft flow demonstrated a mild correlation with the size of the native coronary artery bypassed ( R = 0.47, P ≤ 0.02).

Conclusions:

Basal flow through free arterial grafts is equivalent to saphenous vein grafts and is primarily determined by the native coronary vessels. The flow reserve for free arterial conduits is more than adequate for coronary bypass surgery.
Effects of a New Cardiomyoplasty Technique on Cardiac Function
Authors: El Oakley Reida M. , Jarvist Jonathan C.
Published: September 2024

Objective:

The current cardiomyoplasty technique was modified to maintain the resting tension of the latissimus dorsi muscle and to prevent lateral movement of the heart during muscle stimulation. The aim of this study is to compare the short term hemodynamic effects of the new cardiomyoplasty wrap (W1) with those of the clinically applied cardiomyoplasty wrap (W2). Preliminary indications of the long-term hemodynamic effects of W1 are presented.

Methods:

In three acute experiments in sheep mean central venous pressure (MCVP), mean arterial pressure (MAP), mean cardiac output (MCOP), mean left ventricular systolic pressure (MLVSP). and mean left ventricular diastolic pressure (MLVDP) were measured for 30 s before and five minutes after applying each procedure with and without stimulation of the muscle graft. The same parameters were also recorded 5 min after removing each muscle wrap. Hemodynamic changes associated with unstimulated muscle wraps were compared to the baseline data. Hemodynamic effects of muscle stimulation were determined by comparing the assisted to the preceding unassisted cardiac cycle. The long-term effects of W1 on the hemodynamics of another three sheep were studied at 6–12 months after the operation. The viability of the muscles used in the chronic experiments were evaluated by morphometric analysis.

Results:

Unstimulated W2 significantly increased mean central venous pressure and reduced mean cardiac output. It also increased mean left ventricular diastolic pressure and reduced peak negative dP/dt. Unstimulated W1 had no deleterious effect on mean central venous pressure, mean left ventricular diastolic pressure or peak — dP/dt, but it also reduced mean cardiac output and increased mean left atrial pressure (MLAP). Synchronised muscle stimulation, in both techniques, augmented the mean arterial pressure, mean cardiac output and mean left ventricular systolic pressure. In W2, however, myostimulation was also associated with a significant increase of the mean left ventricular diastolic pressure. In two long-term experiments significant hemodynamic assistance was observed at 6 months and at 1 yr after W1. In those sheep 68% of the cross-sectional area of the muscle was well preserved.

Conclusions:

Unstimulated cardiomyoplasty wraps acutely impair left ventricular function in sheep. The new technique, however, may offer significant long-term hemodynamic assistance and adequate preservation of the structural and functional integrity of the muscle flap for up to 1 yr.
Is Posterior Leaflet Preservation in the Surgical Treatment of Rheumatic Mitral Insufficiency without Left Ventricular Dysfunction Necessary?
Authors: Kirali Kaan , Tuncer Altuǧ , Uyar İbrahim , Mansuroǧlu Denyan , Daǧlar Bahadir , İpek Gökhan , Işik Ömer , Yakut Cevat
Published: September 2024

Preservation of the mitral valve leaflet and tensor apparatus during valve replacement is believed to maintain left ventricular performance. To determine the effect of posterior leaflet preservation in pure severe mitral insufficiency without left ventricular dysfunction 56 patients were operated on between 1993 and 2000. Twenty-three patients underwent mitral valve replacement with posterior chordal preservation and 33 patients underwent mitral valve replacement with chordal transection. Preoperative data in the both groups were similar. After 30 days there were no mortalities observed. Dimensions of the left ventricle had significantly decreased within one group, but there was no difference in the other group. The improvement of the functional and cardiac performance in all patients was significant without any difference between the two groups. Actuarial freedom from death was not significantly different at 6 yr ( P = 0.23). To preserve left ventricular function in pure severe mitral regurgitation without left ventricular dysfunction, mitral valve replacement is very effective with or without posterior leaflet preservation. But, it is difficult to suggest that posterior leaflet preservation alone can increase cardiac performance.
Familial Abdominal Aortic Aneurysms in the Otago Region of New Zealand
Authors: Rossaak J.I. , Hill T.M. , Jones G.T. , Phillips L.V. , Harris E.L. , van Rij A.M.
Published: September 2024

Purpose:

To investigate the familial incidence and phenotypic characteristics of patients with abdominal aortic aneurysms (AAA) in the Otago region of New Zealand.

Methodology:

A retrospective audit based pilot study and a prospective study of patients having abdominal aortic aneurysm repair from September 1988 to September 1999 was performed.

Results:

248 probands were enrolled, of which 19.4% had one or more first degree relative affected. The age at diagnosis of the familial (70.2) and non-familial (70.5) patients was similar. The proportion of females was increased in the familial subgroup. Hypercholesterolaemia was the only phenotypic feature to differentiate familial from non-familial patients and was associated with an earlier age of presentation. In the familial families, brothers were the most common relative affected and 77% of the families had two patients with AAA.

Conclusion:

19.4% of patients operated on in the Otago area for AAA had a familial component to their aneurysm.
Mitral and Mitro-Aortic Valve Replacement with Sorin Bicarbon Valves Compared with St. Jude Medical Valves
Authors: Camilleri L.F. , Bailly P. , Legault B.J. , Miguel B. , D'Agrosa-Boiteux M.-C. , de Riberolles C.M.
Published: September 2024

Objective:

We assessed the clinical results of two bileaflet mechanical valves: the St. Jude Medical (SJM) and the Sorin Bicarbon (Sorin Bicarbon) used either in single mitral valve replacement (MVR) or in double, aortic and mitral, valve replacement (DVR).

Methods:

Between September 1990 and November 1995, 217 patients received either a St. Jude Medical ( n = 134) or a Sorin Bicarbon ( n = 86): 136 mitral valve replacement with 83 St. Jude Medical and 53 Sorin Bicarbon and 84 double valve replacement with 51 St. Jude Medical and 33 Sorin Bicarbon. There was no difference between both St. Jude Medical and Sorin Bicarbon cohorts in respect of mitral valve physiopathology, etiology of valve disease, associated lesions, echocardiographic and hemodynamic data. The only significant preoperative difference was the age of patients within the double valve replacement group and the size of implanted valves within the mitral valve replacement group. Follow-up was 100% complete with a mean of 39±18 months, ranging between 6 and 68 months. The total follow-up was 657 patient-years (pt-y): 396 pt-y in the mitral valve replacement group and 274 pt-y in the double valve replacement group.

Results:

Hospital mortality (St. Jude Medical: 2.2%; Sorin Bicarbon: 6.9%) and late mortality (St. Jude Medical: 8.4%; Sorin Bicarbon: 6.3%) were not significantly different. Ten deaths were considered valve-related (St. Jude Medical 6, Sorin Bicarbon 4). The estimated 4-yr overall survival, including hospital mortality, was for St. Jude Medical-mitral valve replacement: 89±4% and St. Jude Medical-double valve replacement: 93±4%, and for Sorin Bicarbon-mitral valve replacement: 87±5% and Sorin Bicarbon-double valve replacement: 91±5%. The linearized incidence (% per pt-y) of valve-related complications was 6.39 in the St. Jude Medical cohort and 9.2 in the Sorin Bicarbon cohort. The linearized incidence (% pt-y) of the prevalent complication, valve thromboembolism and bleeding, was for St. Jude Medical-mitral valve replacement: 3.41, St. Jude Medical-double valve replacement: 3.16 and for Sorin Bicarbon-mitral valve replacement: 2.17 and Sorin Bicarbon-double valve replacement: 3.67. The differences between each group of an estimated 4-yr freedom from combined thromboembolism and bleeding were not significant (St. Jude Medical-mitral valve replacement: 90±4%, St. Jude Medical-double valve replacement: 84±6%, and for Sorin Bicarbon-mitral valve replacement: 94±3% and Sorin Bicarbon-double valve replacement: 75±17%).

Conclusions:

In this clinical non-randomized study, there was no evidence of any significant difference between St. Jude Medical and Sorin Bicarbon valves over a 4-yr follow-up.
Microperfusion Enhancement after TMLR in Chronically Ischemic Porcine Hearts
Authors: Lutter Georg , Martin Juergen , von Samson Patrick , Heilmann Claudia , Sarai Koppany , Beyersdorf Friedhelm
Published: September 2024

Objective.

The purpose of this study was to determine the effect of transmyocardial laser revascularization (TMLR) on myocardial perfusion and function in chronically ischemic myocardium.

Methods.

In the first operation a stenosis of the left anterior descending artery was created in 20 open-chest anesthetized pigs to implement this ischemic model. In contrast, four pigs served as controls (thoracotomy only). Seven days later (2nd operation), all animals were studied at baseline by analyzing different parameters of perfusion (radioactive microspheres), function, and intramyocardial pressure. Afterwards, pigs who received a left anterior descending artery stenosis were randomized into one of three groups: animals in laser group 1 ( n = 7) received one and in laser group 2 ( n = 7) two laser channels per cm2 in the left anterior descending artery territory. Animals of the ischemic group ( n = 6) underwent the same procedures without transmyocardial laser revascularization. Three months later, the animals were re-studied (3rd operation) and additional analysis of histochemistry and myocardial water content was performed.

Results.

Regional myocardial blood flow (RMBF) in laser group 2 revealed statistically higher RMBF values compared to the ischemic group (0.39±0.13 versus 0.14±0.12 ml/min/g; P = 0.043), after 3 months, whereas the absolute RMBF had not increased compared to the 1-week baseline values. Left ventricular stroke work index (LVSWI) at rest and under stress did not show any improvement compared to the initial values in all study groups ( P = ns). Nevertheless, laser group 1 demonstrated relatively higher LVSWImax values compared to the ischemic (1.33±0.19 versus 0.93±0.16 mJ/kg; P = 0.03) and laser group 2 (1.33±0.19 versus 1.02±0.15; P = 0.024). Regional contractility of laser groups 1 and 2 recovered after 3 months (which had deteriorated shortly after transmyocardial laser revascularization) and increased under stress (100% versus 144.33±46.42, P = 0.029 and 100% versus 116.26±21.06, P = 0.034; respectively). In contrast, the corresponding ischemic group values were not different from intial values ( P = ns).

Conclusions.

This model of chronic regional ischemia demonstrates that CO2-laser revascularization significantly improves microperfusion and regional function, whereas the overall perfusion and global LV function is unchanged.
Aortic Repair in Marfan's Syndrome: Prevention of Mechanical Leaflets Damage
Authors: Gelsomino Sandro , Frassani Romeo , Porreca Lorenzo , Livi Ugolino
Published: September 2024

Aortic incompetence in Marfan's syndrome results from distortion or dilatation of the sinuses of Valsalva, annuloaortic ectasia or a combination of these problems. Valve leaflets in these patients are macroscopically normal in spite of aortic insufficiency. Replacement of the ascending aorta, root and aortic valve with a composite graft was, for a long time, the treatment of choice for Marfan patients. Valve-preserving procedures (remodeling or reimplantation) provide the advantages of avoiding the shortcomings of standard surgical techniques, and maintaining the functional integrity of the left ventricular (LV) outflow tract, aortic root and ascending aorta. We developed a modified valve-sparing reimplantation technique for avoiding leaflet damage. This was achieved by leaving a ‘cushion’ of aortic wall (8–10 mm) that, sewn on the Dacron graft, works as a ‘damper’ and prevents leaflets injury during the systolic opening of the valve. For final judgment of this operative method long-term results are necessary.
Expression of Apoptosis-Related Proteins and Structural Features of Cell Death in Explanted Aortocoronary Saphenous Vein Bypass Grafts
Authors: Wang A.Y. , Bobryshev Y.V. , Cherian S.M. , Liang H. , Tran D. , Inder S.J. , Lord R.S.A. , Ashwell K.W.S. , Farnsworth A.E.
Published: September 2024

This study aimed to investigate the features of cell death occurring in aortocoronary saphenous vein bypass grafts. Human aortocoronary saphenous vein bypass grafts with angiographic luminal stenosis of >75% were explanted from 14 patients at redo coronary artery bypass grafting. Proteins associated with apoptotic pathways were identified immunohistochemically using antibodies to Bcl-2, Fas, BAX, p53 and CPP32. Cells undergoing DNA fragmentation were identified by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). DNA synthesis was investigated using the antibody to proliferating cell nuclear antigen (PCNA). Ultrastructural features of cell death were examined by electron microscopy. Anti-apoptotic (Bcl-2) and pro-apoptotic (Bax, p53, CPP32 and Fas) proteins were expressed throughout the graft wall, but marked differences in the characteristics of cell death were noted between atherosclerotic and non-atherosclerotic areas of the intima. In atherosclerotic areas, pro-apoptotic proteins were widely expressed, but ultrastructural analysis failed to identify cells showing typical features of apoptosis. In these areas, necrotic cells were frequently observed, with negative correlation of Bcl-2 expression with TUNEL. Pro-apoptotic proteins showed no correlation with TUNEL. In contrast, in non-atherosclerotic areas of vein grafts, the expression of both anti-apoptotic (Bcl-2) and pro-apoptotic proteins (p53. Bax and CPP32) correlated with TUNEL. In atherosclerotic areas, non-atherosclerotic intimal areas, and in the underlying media, the numbers of TUNEL+ cells correlated with PCNA positivity. Ultrastructurally, apoptotic bodies and features of necrosis were observed in non-atherosclerotic areas of grafts. The present observations indicate that in atherosclerotic areas, cell death occurs mainly by necrosis, while in non-atherosclerotic areas, cell death occurs by both necrosis and apoptosis. An imbalance between DNA fragmentation and DNA synthesis may contribute to graft instability and failure.
Metabolic Changes in the Ischemic Penumbra after Carotid Endarterectomy in Stroke Patients by Localized in Vivo Proton Magnetic Resonance Spectroscopy (1H-MRS)
Authors: Kim Geun Eun , Lee Jung Hee , Cho Yong Pil , Kim Sang Tae
Published: September 2024

Carotid endarterectomy (CEA) is known to be effective in reducing recurrent ischemic attacks, sometimes accompanied with the functional improvement, for patients with internal carotid artery (ICA) flow lesions by increase in perfusion and/or removal of embolic sources. However, the exact mechanism of how the CEA affects the cerebral metabolism in relations to the perfusion increase in noninfarcted hypoperfused peripheral areas to the center of the lesion (e.g., ischemic penumbra or border zone) is not yet clearly known. The existence of the ischemic penumbra and its long-term viability has also been argued. We designed a prospective study to investigate the metabolic changes in the ischemic penumbra for patients with ICA flow lesions and cerebral infarct (or ischemia) before and after CEA using localized in vivo proton magnetic resonance spectroscopy (1H-MRS). The results of 1H-MRS showed significantly decreased choline (Cho)/creatine (Cr) and increased N-acetylaspartate (NAA)/Cho ratios in the periphery of the lesion for the patients after CEA as compared to those who underwent only medical treatments. The more significant changes in the cerebral metabolite levels were observed in the patients who showed the improved cerebral perfusion by single photon emission computed tomography after CEA than in those who did not. In conclusion, our data suggest the existence of the ischemic penumbra, which were viable for a longer period than previously thought: CEA seems to improve the cerebral metabolism that may result from the improved perfusion at the ischemic penumbra.
Femoro-Popliteal Reconstructions: ‘In Situ’ versus ‘Reversed’ Technique
Authors: Davidovic Lazar B. , Markovic Dragan M. , Vojnovic Bojan R. , Lotina Slobodan I. , Kostic Dusan M. , Cinara Ilijas S. , Cvetkovic Slobodan D. , Jakovljevic Nenad S.
Published: September 2024

This study examined 191 patients with ‘reversed’ and 99 patients with ‘in situ’ femoro-popliteal bypass technique. There were 85 diabetic patients (44.5%) in the group with ‘reversed’ bypass, and 43 patients (43.43%) in the ‘in situ’ group. There were 152 (79.68%) smokers in the ‘reversed’ bypass group, and 80 (80.8%) in the ‘in situ’ group. The graft patency was confirmed immediately after operation using CW Doppler and then followed up after 1, 6, 12 months and annually thereafter. The statistical analysis was performed using Pearsons chisquare test. Fischer's test, and ‘Life table’ statistic methods. The patients were followed from 3 to 10 yr after surgery. ‘In situ’ bypass showed better patency than the ‘reversed’ bypass technique but only in the second and tenth follow-up year ( P<0.05). Also, ‘in situ’ bypass proved to be better than ‘reversed’ only in patients with one patent crural artery ( P<0.01). Diabetes and preoperative smoking did not significantly affect late patency regarding this technique ( P>0.05). However, continuous smoking after the operation significantly decreased late patency rate in both groups of patients ( P<0.01). There was no significant difference in the early thrombectomy rate between groups with ‘reversed’ and ‘in situ’ bypasses ( P>0.05). The early thrombectomy, however, significantly reduced late patency rate in both groups ( P<0.01). Therefore we suggest ‘in situ’ bypass in cases with poor run off, small-calibre vein and ‘long’ bypass. Also, we consider important more frequent physical and Doppler ultrasonographic control in patients who had early thrombectomy.