bluuebunny/crossref_metadata_2025 huggingface dataset:
Lubricant savings in sheet metal forming through thermally oxidized wear protection layers
Authors: Müller P. , Holländer U. , Lendiel I. , Maier H.-J. , Hübner S. , Wehmeyer J. , Fünfkirchler T. , Behrens B.-A.
Published: May 2024

Increasing demands on quality, variety of shapes and complexity of deep-drawn components with simultaneous price stability make the development of innovative solutions in the field of deep-drawing indispensable. For ecological and economic reasons, there is a great interest in reducing the amount of lubricant required in forming processes to a minimum. In this work, tool coatings for forming tools are to be investigated and further developed in order to use their friction-reducing properties on the tribo-system and thus enable a reduction in the use of lubricants. For this purpose, in this research strip drawing tests are carried out to investigate the friction-influencing properties of different coatings and their potential for lubricant saving. Therefore, cylindrical forming heads are provided with different coating systems. Strips of aluminum sheet are drawn around the forming heads at an angle of 90°. The amount of lubricant applied is varied. Friction values are recorded and analyzed for each system. Wear mechanisms are identified, examined and evaluated macroscopically and microscopically. For this purpose, energy dispersive X-ray spectroscope (EDX) and scanning electron microscope (SEM) examinations are carried out. A statement on the potential of the investigated coatings for lubricant saving is derived from the results.
Influence of local heat treatment of rivets on the joint formation of a versatile joining process
Authors: Kappe F. , Bobbert M. , Meschut G.
Published: May 2024

An efficient lightweight construction method is the combination of different materials in order to adapt the structure to the applied load. To join these multi-material structures mechanical joining technologies are applied. However, the rigid tooling systems cannot be adjusted to changing boundary conditions which is why new, versatile joining technologies are required. In the versatile self-piercing riveting (V-SPR) process presented in [1] different material combination are joined by using a multi-range capable rivet. The rivet head is formed onto the respective thickness of the joint by an outer punch. In order to punch thru the upper sheet a great rivet hardness is required whereas a lower hardness is required for the subsequent forming of the rivet head. To achieve a combination of these requirements, this study investigates a local heat treatment of the rivet. The aim is to determine the feasibility of such a heat treatment as well as to investigate the influence on the joint formation.
Ductile fracture of tubular specimens under non-proportional loading condition
Authors: Baral Madhav , Korkolis Yannis P.
Published: May 2024

The ductile fracture behaviours of two tubular specimens, a AA6260-T4 macrotube (60 mm diameter and 2 mm thickness), and a SS-304L microtube (2.38 mm diameter and 0.15 mm thickness) under non-proportional loading condition are studied using a combined experimental-numerical approach. The experiments are conducted by loading the tubes under axial force and internal pressure along various non-proportional (i.e., corner) paths until failure by controlling the force/pressure ratio. The plastic behaviours of the tubes are characterized using the non-quadratic anisotropic yield criteria Yld2000-2D and Yld2004-3D. The material models are employed in the finite element (FE) simulation of the tube experiments using Abaqus/Standard (implicit). The FE models, which include thickness imperfection to capture the failure modes observed in the experiments, are then used to probe the fracture parameters inside the tube wall where fracture is likely to initiate. It is observed that the fracture strains from the non-proportional loading results are noticeably different when introduced to the proportional fracture strains, revealing the path-dependence fracture behaviour in tubular specimens.
Study on GISSMO fracture model of hot-stamped Tailored-Tempering-Properties parts
Authors: Qiu B Y , Wang Y L , Zhu B , Liu W , Zhang Y S , Ren X Q , Ren X P
Published: May 2024

To accommodate the varying mechanical demands in different areas of vehicle components, the Tailored-Tempering-Properties technology of hot-stamped parts of high-strength steel came into being. This research crafted a segregated hot and cold partition die system to fabricate U-shaped parts from 22MnB5 with Tailored-Tempering-Properties. The sides and bottom surfaces of the hard and soft zones of the U-shaped parts were sampled, and uniaxial tensile experiments were carried out to obtain the stress-strain curve, tensile strength, and elongation. In addition, notch, shear, and tensile shear sampling were carried out in the soft area at the bottom flange of the U-shaped part, and the force-displacement curve and fracture strain under different stress conditions were determined by tensile test. The GISSMO fracture model was selected to simulate the failure fracture of the material, and the parameters were obtained by Hypermesh pretreatment, LS-DYNA solution calculation, and LS-OPT optimization. Finally, the GISSMO fracture model suit for the soft zone of 22MnB5 U-shaped parts was obtained to characterize and predict its fracture behavior, which is an essential basis for guiding the design and optimization of parts.
Holistic springback compensation procedure
Authors: Zimmermann P , Birkert A , Saup P , Marner F , Häussermann M
Published: May 2024

The elastic springback during the manufacturing process of stamped car body components causes dimensional deviations. To compensate these deviations, the common approach is to modify the tool surfaces in the opposite direction of the deviations – this is called springback compensation. In the procedure of springback compensation various issues must be solved. To achieve the main goal of a dimensionally accurate part, it must be ensured that, on the one hand the distance normal to the sheet surface between the springback part and the target geometry is within a specified dimensional tolerance. On the other hand, it must be ensured that the surface areas and characteristic lengths of the springback part and that of the target geometry match as closely as possible. In the past, approaches/methods, such as the physical compensation method and the physical scaling approach, have been presented which can successfully counteract these problems. Furthermore, in a multi-stage process in subsequent operations a stable part position must be achieved and unwanted plastic deformations must be avoided during blankholder closing. Therefore, different compensation strategies have been presented, which can fulfil these requirements. However, in the publication of these methods, the problems were always considered individually. This paper shows how all the named requirements can be achieved by combining the individual methods in springback compensation.
Creating a Virtual Shadow of the Manufacturing of Automotive Components
Authors: Barlo A , Aeddula O , Chezan A R , Pilthammar J , Sigvant M
Published: May 2024

Within the automotive industry, there is an increasing demand for a paradigm shift in terms of which materials are used for the manufacturing of the automotive body. Global climate goals are forcing a rapid adaption of new, advanced, sustainable material grades such as the fossil free steels and materials containing higher scrap content. With the introduction of these new and untested materials, methods for accounting for variation in material properties are needed directly in the press lines.

The following study will focus on creating an initial virtual shadow of the manufacturing of a Volvo XC90 inner door panel through the application of Artificial Neural Networks (ANN). The virtual shadow differs from the concept of the digital twin by only being a virtual representation of the production line, with training data generated exclusively by numerical simulations, and having no automated communication with the physical press line control system. The virtual shadow can be used as an assistance to the press line operators to see how different press line settings and material parameter variations will impact the quality of the stamped component. The study aims to validate the virtual shadow through accurate predictions of the material draw-in measured in the physical press line.
Development of a digital material shadow for the press hardening route of medium manganese steel
Authors: Tilly Karl J. , Idzik Christian , Bailly David
Published: May 2024

Press-hardened ultra-high strength steel parts are widely used in the automotive sector for their lightweight and safety advantages. Medium-Manganese Steels (MMnS) are being explored as an alternative to boron-manganese steels due to their high strength and ductility after quenching, achieved at lower annealing temperatures thus reducing energy usage and carbon emissions. However, industrial adoption of MMnS is hindered by challenging processing requirements, e.g. in cold-rolling and press hardening.

To expedite and improve the process development, data-driven decisions based on process parameters hold promise. Establishing a link between process data and the final produced part necessitates the development of a framework for a Digital Material Shadow (DMS).

This paper investigates the development of a DMS framework for the cold rolling and press hardening process chain. In conjunction with conventional data acquisition methods employed for cold rolling, novel data acquisition techniques are introduced specifically tailored for press hardening, ensuring the comprehensive availability of relevant data. Moreover, a data pipeline is implemented to enable automatic processing, visualization, and analysis of process data. To facilitate seamless data linkage across processes in the DMS, an ID-system is introduced. Finally, the developed framework’s validity is demonstrated by creating a DMS for press-hardened MMnS parts, showcasing its potential for practical applications.
Optimizing Reverse-Engineered Finite Element Models for Accurate Predictions of Experimental Measurements
Authors: Chezan A R , Dhawale T , Atzema E H , Barlo A , Aeddula O , Pilthammar J , Sigvant M , Langerak N A J
Published: May 2024

This study investigates the challenges of reverse engineering in finite element modelling of sheet metal forming, specifically for the Volvo XC90 front door inner component. Advanced models incorporating anisotropic behaviour of steel and non-linear friction are compared against actual real-world measurements. The methodology involves simplifying complex continuous parameters into more manageable representative data sets and assessing model accuracy under both uniform and varied blank holder force settings, guided by measured contact pressure distributions. Although the results indicate an improvement in accuracy, they underscore the need for additional methodological improvements and more accurate replication of tooling effects to enhance the fidelity and effectiveness of these models.
Influence of Hole Preparation Technique on Stretch Flangeability of Aluminium Alloys
Authors: Kumar Vinay , Kumar D Ravi
Published: May 2024

Application of aluminium alloys has increased for light-weighting the sheet metal parts in manufacturing of automobiles. Formability is important in sheet metal forming of aluminium alloys. In the assessment of formability of sheet metals, stretch flangeability or edge formability is an important aspect in application such as flanges or plunged rims. The stretch flangeability refers to the ability to avoid cracking during hole expansion and it is evaluated by performing the hole expansion test. Besides material properties, hole making process also influences the stretch flangeability of aluminium alloys. In this work, the stretch flangeability of two Al-Mg alloys has been investigated through hole expansion tests by using three different hole making techniques namely punching, water jet cutting and laser cutting. The stretch flangeability of aluminium alloys has been compared with that of a high strength steel (Dual phase steel of grade DP600) which is more commonly used steel for stretch flanging applications.
Process design for flexible T-profile-rolling of tailored thickness stringers with different cross sections
Authors: Aign F S , Kilz J , Groche P
Published: May 2024

A new process, called flexible T-profile-rolling, is being developed to produce T-profiles with variable thickness distribution in longitudinal direction by flexible rolling. These tailored thicknesses allow for load-adapted and weight-optimised design of stringer profiles for aircrafts. The new process can replace the chemical milling currently used in the production of stringers and enables a more environmentally friendly and resource-saving production of the thickness changes. In order to achieve uniform thicknesses in the web and flange of the T-profile, a new rolling stand with rolls inclined against the T-profile and varying roll radii was developed. However, the varying roll radii cause different longitudinal strains in the profile cross-section due to the varied contact areas between the roll and the rolling stock, resulting in unwanted profile bowing. This bowing depends on the profile dimensions, as the adjacent roll radii vary over the profile cross-sections.

This paper demonstrates the effects of profile dimensions on deflection through numerical investigations with different web heights, flange widths and thickness reductions. A straightening method is presented to obtain straight profiles as a function of the profile dimensions. The results show that this process can produce almost straight T-profiles with variable thicknesses for different cross section dimensions.
Air pollution impact on forecasting electricity demand utilizing CNN-PSO hyper-parameter optimization
Authors: Birdal Ramiz Gorkem
Published: May 2024

Electricity consumption is expected to increase considerably in the next few years, so forecasting and planning will become more important. A new method of forecasting electricity loads based on air pollution is presented in this paper. Air pollution indirect effects are not incorporated in current evaluations since they rely primarily on weather conditions, historical load data, and seasonality. The accuracy of electricity load forecasting improved by incorporating air pollution data and its potential effects, especially in regions where air quality heavily impacts energy consumption and generation patterns. This robust prediction model is capable of capturing the complex interactions between air pollution and electricity load by integrating innovative environmental factors with historical load data, weather forecasts, and other features. As part of the second contribution, we use metaheuristic algorithms to optimize hyper parameters, which provide advantages such as exploration capability, global optimization, robustness, parallelization, and adaptability making them valuable tools to improve machine learning models’ performance and efficiency. The study found that the correlation coefficient (R) between predicted and real electricity demand and supply was high, at 0.9911. Beyond that this approach reduces MAPE by up to 19.5% when CNN and particle swarm optimization are combined with utilizing innovative air pollution variables. As a result, the optimization results were robust compared to state-of-the-art results based on statistical metrics such as RMSE and MAPE. Lastly, we emphasize the importance of factoring in air pollution effects when forecasting and managing electricity loads; future research directions include developing integrated modeling frameworks that reflect the dynamic interaction between air quality, energy consumption, and renewable energy generation.
Water level measurement for reservoir dams with robotic total station during displacements monitoring
Authors: Zhou Jianguo , Gao He , Xiao Wei , Peng Duo
Published: May 2024

This study proposes a novel method for water level measurement of reservoir dams by utilizing the image sensor of robotic total station rather than requiring a staff gauge during displacements monitoring. The robotic total station is first aimed at the waterline manually and an image is captured by the telescope coaxial camera to obtain the initial elevation and waterline equation. In the periodic measurement stage, the zenith angle of the telescope is adjusted according to the predicted result to take pictures, and the waterline is extracted based on the parameters of the initial waterline equation through image processing technologies. The waterline is verified, and the water level elevation is estimated then. Simulation and field test results show that waterline extraction error affects the accuracy of the proposed method most, and an accuracy of around 2 pixels can be achieved for the waterline extraction method. And a water level measurement result with centimeter-level accuracy at a distance of about 350 m can be expected, which has engineering application prospect.
The Cambridge and London Experiences of Joseph Hussey
Authors: Dunan-Page Anne
Published: May 2024

This chapter examines the manuscript works of the Cambridge and London dissenting minister Joseph Hussey (1660–1726). Such archival documents help reassess the transformation of Calvinistic culture after the Toleration Act, but this chapter argues that they also contain evidence for the history of literature. Joseph Hussey’s unpublished works first question the nature of pastoral diaries, sometimes called ‘church books’, but also give detailed accounts of the practice of conversion narratives in early eighteenth-century Congregational churches. After rehearsing the complex nature of Hussey’s diary, and the problem of denominational identity among Presbyterians and Congregationalists, I turn to Hussey’s presentations of oral and written conversion narratives given in his congregations. The rich vocabulary of emotions that both applicants and hearers were expected to encounter shaped the delivery of the narratives at times along gender lines.
Introduction
Authors: Constantine Mary-Ann
Published: May 2024

This chapter opens with two very different encounters between English tourists and ‘native’ Welsh locals at Llanberis Lakes in the late 1790s. Pursuing those differences, it argues that the genre of the ‘home tour’ offers a varied and under-exploited body of material of interest across a number of disciplines, and occupies an interesting position at the intersection of literary and historical studies. Situating such encounters as examples of ‘cultural entanglement’, it focuses on three topics explored in more detail across the book: contact with and representations of Welsh language and culture; political and social unrest; and, responding to recent work by Andreas Malm and others, environmental history.
Epilogue and Conclusion
Authors: Finkel Stuart
Published: May 2024

The Epilogue opens with a conservative’s triumphal 1887 account of the failures of prisoner aid as part of a thorough routing of “nihilism.” This, however, while technically accurate on the initial struggles of émigré aid, missed less public activity and the persistence of covert domestic efforts, where authorities remained gravely concerned with charitable events serving as subterfuge for illicit fundraising. This shows, it is argued, how political philanthropy occupied a liminal space linking radicals to a broader circle of educated sympathizers and provided a connective tissue allowing the revolutionary/liberationist movement to be construed as continuous and cohesive. The 1890s, it is then noted, featured a resumption of efforts abroad, with newly arrived émigrés spurring Lavrov to head a Central Kassa in Paris, with an affiliate in Zurich. At the same time, the continuous existence of the St. Petersburg Society to Aid Political Exiles and Prisoners and the revival of its Moscow counterpart in the early to mid-1890s drew in the next generation of revolutionary leaders. With the upsurge of both worker and student activity later in the decade, Zasulich made appeals in London, while “Red Cross” groups proliferated throughout Russia, presaging even broader and larger organizations after the turn of the century.
Micro-Coring: A Novel Approach to Perioral Rejuvenation
Authors: Carruthers Katherine H , Vyas Krishna , Remy Katya , McCarty Justin C , Austen William G
Published: May 2024

Background

A long philtrum and poor perioral skin quality are stigmata of the aging face. Micro-Coring is a novel technology that allows for scarless skin removal.

Objectives

In this study we aimed to determine whether micro-coring can shorten the philtrum and improve perioral skin quality.

Methods

A retrospective cohort study was performed on patients who underwent facelift with perioral micro-coring and age- and BMI-matched controls who underwent facelift alone. Preoperative and postoperative 3-dimensional facial imaging was performed. Standard perioral distances and percentage of change were calculated. Perioral skin quality was evaluated by blinded raters with the Scientific Assessment Scale of Skin Quality (SASSQ) and Global Aesthetic Improvement Scale (GAIS).

Results

Thirteen patients and 13 controls were included, with a mean follow-up of 8.9 months (range 3.0-21.5). Patients had significantly shorter mean philtrum length postoperatively compared to preoperatively, with an average decrease of 6.18% (±2.25%; P < .05). Controls did not experience significant changes in philtrum length (P > .05). There were no significant changes in other perioral measurements. Perioral skin elasticity and wrinkles significantly improved in patients compared to controls and patients had significantly greater GAIS scores (P < .05).

Conclusions

Micro-Coring can achieve perioral rejuvenation through measurable shortening of the philtrum and observable improvement in skin quality. Nonsurgical techniques continue to find new ways to achieve aesthetic goals without significant recovery or scarring and offer value to patients and clinicians.

Level of Evidence: 3
Counting the Ways That Aboriginal and Torres Strait Islander Older People Participate in Their Communities and Culture
Authors: Luke Joanne Nicole , Bessarab Dawn , Smith Kate , LoGiudice Dina , Flicker Leon , Gilchrist Lianne , Dow Briony , Temple Jeromey
Published: May 2024

Objectives

This study aimed to determine the proportion of older Aboriginal and Torres Strait Islander peoples participating in cultural events and activities and determine the demographic and sociocultural characteristics associated with participation.

Methods

The Australian Bureau of Statistics National Aboriginal and Torres Strait Islander Social Survey (2014–2015) was used to measure the prevalence of participation in cultural events and activities. Multivariate logistic regression models were used to measure associations. Sociocultural factors were selected by matching survey items to the 12 sociocultural factors described in the Good Spirit Good Life Framework, a culturally validated quality-of-life tool for older people.

Results

The majority (62.0%) of survey respondents 45 years and older participated in cultural events (e.g., ceremonies, funerals/sorry business, NAIDOC week activities, sports carnivals, festivals/carnivals) or were involved in organizations. Many (58.5%) also participated in activities (e.g., fishing, hunting, gathering wild plants/berries, arts/crafts, music/dance/theater, writing/telling of stories). In regression models including demographic and cultural variables, participation in cultural events was highest among people living remotely (odds ratio [OR] = 2.71), reporting recognition of homelands (OR = 2.39), identifying with a cultural group (OR = 3.56), and those reporting having a say in their communities (OR = 1.57), with similar odds seen for participation in activities. Participation was inversely proportional to increasing age, with a greater proportion of females participating in events and males in activities.

Discussion

The social lives of older Aboriginal and Torres Strait Islander people were characterized by widespread participation in cultural events and activities. These findings provide important insights into services as they support older people to live a good life.
Fundamental Monopole Operators and Embeddings of Kac-Moody Affine Grassmannian Slices
Authors: Muthiah Dinakar , Weekes Alex
Published: May 2024

Braverman, Finkelberg, and Nakajima define Kac-Moody affine Grassmannian slices as Coulomb branches of $3d$  ${\mathcal{N}}=4$ quiver gauge theories and prove that their Coulomb branch construction agrees with the usual loop group definition in finite ADE types. The Coulomb branch construction has good algebraic properties, but its geometry is hard to understand in general. In finite types, an essential geometric feature is that slices embed into one another. We show that these embeddings are compatible with the fundamental monopole operators (FMOs), remarkable regular functions arising from the Coulomb branch construction. Beyond finite type these embeddings were not known, and our second result is to construct them for all symmetric Kac-Moody types. We show that these embeddings respect Poisson structures under a mild “goodness” hypothesis. These results give an affirmative answer to a question posed by Finkelberg in his 2018 ICM address and demonstrate the utility of FMOs in studying the geometry of Kac-Moody affine Grassmannian slices, even in finite types.
Metabolite cross-feeding enables concomitant catabolism of chlorinated methanes and chlorinated ethenes in synthetic microbial assemblies
Authors: Chen Gao , Yang Yi , Yan Jun , Löffler Frank E
Published: May 2024

Isolate studies have been a cornerstone for unraveling metabolic pathways and phenotypical (functional) features. Biogeochemical processes in natural and engineered ecosystems are generally performed by more than a single microbe and often rely on mutualistic interactions. We demonstrate the rational bottom-up design of synthetic, interdependent co-cultures to achieve concomitant utilization of chlorinated methanes as electron donors and organohalogens as electron acceptors. Specialized anaerobes conserve energy from the catabolic conversion of chloromethane or dichloromethane to formate, H2, and acetate, compounds that the organohalide-respiring bacterium Dehalogenimonas etheniformans strain GP requires to utilize cis-1,2-dichloroethenene and vinyl chloride as electron acceptors. Organism-specific qPCR enumeration matched the growth of individual dechlorinators to the respective functional (i.e. dechlorination) traits. The metabolite cross-feeding in the synthetic (co-)cultures enables concomitant utilization of chlorinated methanes (i.e. chloromethane and dichloromethane) and chlorinated ethenes (i.e. cis-1,2-dichloroethenene and vinyl chloride) without the addition of an external electron donor (i.e. formate and H2). The findings illustrate that naturally occurring chlorinated C1 compounds can sustain anaerobic food webs, an observation with implications for the development of interdependent, mutualistic communities, the sustenance of microbial life in oligotrophic and energy-deprived environments, and the fate of chloromethane/dichloromethane and chlorinated electron acceptors (e.g. chlorinated ethenes) in pristine environments and commingled contaminant plumes.
Cyst of the Canal of Nuck: a case report
Authors: Lukanova Tsonka , Takorov Ivelin , Todorova Elina , Dzakova Ani
Published: May 2024

The cyst of the Canal of Nuck, or hydrocele, is a rare pathological condition in the female inguinal region. We present a 44-year-old female with a cystic lesion in the right inguinal area, detailing clinical symptoms, differential diagnosis and imaging findings. Surgical intervention involved complete cyst excision, with no recurrence during the follow-up. This case underscores the importance of accurate diagnosis and targeted surgical treatment for favourable outcomes in managing rare anatomical variations like the Canal of Nuck cyst.
Non-canonical mRNA translation initiation in cell stress and cancer
Authors: Mahé Mélanie , Rios-Fuller Tiffany , Katsara Olga , Schneider Robert J
Published: May 2024

The now well described canonical mRNA translation initiation mechanism of m7G ‘cap’ recognition by cap-binding protein eIF4E and assembly of the canonical pre-initiation complex consisting of scaffolding protein eIF4G and RNA helicase eIF4A has historically been thought to describe all cellular mRNA translation. However, the past decade has seen the discovery of alternative mechanisms to canonical eIF4E mediated mRNA translation initiation. Studies have shown that non-canonical alternate mechanisms of cellular mRNA translation initiation, whether cap-dependent or independent, serve to provide selective translation of mRNAs under cell physiological and pathological stress conditions. These conditions typically involve the global downregulation of canonical eIF4E1/cap-mediated mRNA translation, and selective translational reprogramming of the cell proteome, as occurs in tumor development and malignant progression. Cancer cells must be able to maintain physiological plasticity to acquire a migratory phenotype, invade tissues, metastasize, survive and adapt to severe microenvironmental stress conditions that involve inhibition of canonical mRNA translation initiation. In this review we describe the emerging, important role of non-canonical, alternate mechanisms of mRNA translation initiation in cancer, particularly in adaptation to stresses and the phenotypic cell fate changes involved in malignant progression and metastasis. These alternate translation initiation mechanisms provide new targets for oncology therapeutics development.
The topography of thought
Authors: Berger Jonah , Toubia Olivier
Published: May 2024

Whether speaking, writing, or thinking, almost everything humans do involves language. But can the semantic structure behind how people express their ideas shed light on their future success? Natural language processing of over 40,000 college application essays finds that students whose writing covers more semantic ground, while moving more slowly (i.e. moving between more semantically similar ideas), end up doing better academically (i.e. have a higher college grade point average). These relationships hold controlling for dozens of other factors (e.g. SAT score, parents' education, and essay content), suggesting that essay topography encodes information that goes beyond family background. Overall, this work sheds light on how language reflects thought, demonstrates that how people express themselves can provide insight into their future success, and provides a systematic, scalable, and objective method for quantifying the topography of thought.
Bone Allograft Pedicle Screw Augmentation
Authors: Lauren Bould , Paul Kooner , Lorne Beckman , Rizkallah Maroun , Steffen Thomas , Loon Jan van , Aoude Ahmed , Ouellet Jean , Kroeze Robert-Jan , Spruit Maarten
Published: May 2024

Study Design:

We performed a comprehensive cadaveric biomechanical study to compare the fixation strength of primary screws, screws augmented with bone allograft, and screws augmented with polymethylmethacrylate cement.

Objective:

To evaluate a novel technique for screw augmentation using morselized cortico-cancellous bone allograft to fill the widened screw track of failed pedicle screws.

Background:

To date, there are no known biological methods available for failed pedicle screw augmentation or fixation.

Materials and Methods:

Biomechanical tests were performed using 2 different testing modalities to quantify fixation strength including axial screw pullout and progressive cyclic displacement tests.

Results:

Fifty vertebrae were instrumented with pedicle screws. Our study showed that bone allograft augmentation using the same diameter screw was noninferior to the fixation strength of the initial screw. In the axial pullout test, screws undergoing bone allograft repair failed at 25% lower loads compared with native screws, and screws augmented with cement showed approximately twice as much strength compared with native screws. In the cyclic displacement test, screws fixed with cement resisted loosening the best of all the groups tested. However, screws augmented with bone graft were found to have an equal strength to native screw purchase. our study did not find a correlation with bone mineral density as a predictor for failure in axial pullout or cyclic displacement tests.

Conclusion:

Bone allograft augmentation for pedicle screw fixation was noninferior to the initial screw purchase in this biomechanical study. This bone allograft technique is a viable option for screw fixation in the revision setting when there is significant bone loss in the screw track.
Effects of a Single Dose of Ayahuasca in College Students With Harmful Alcohol Use
Authors: Rodrigues Lucas Silva , Reis José Augusto Silva , Rossi Giordano Novak , Guerra Lorena T. L. , Maekawa Renan Massanobu , de Lima Osório Flávia , Bouso José Carlos , Santos Fabiana Pereira , Paranhos Beatriz Aparecida Passos Bismara , Yonamine Mauricio , Hallak Jaime Eduardo Cecilio , dos Santos Rafael Guimarães
Published: May 2024

Background

Ayahuasca is a South American plant hallucinogen rich in the psychedelic N,N-dimethyltryptamine and β-carbolines (mainly harmine). Preclinical and observational studies suggest that ayahuasca exerts beneficial effects in substance use disorders, but these potentials were never assessed in a clinical trial.

Methods

Single-center, single-blind, feasibility, proof-of-concept study, assessing the effects of one dose of ayahuasca accompanied by psychological support (without psychotherapy) on the drinking patterns (primary variable) of 11 college students with harmful alcohol consumption. Secondary variables included safety and tolerability, craving, personality, anxiety, impulsivity, self-esteem, and social cognition.

Findings

Ayahuasca was well tolerated (no serious adverse reactions were observed), while producing significant psychoactive effects. Significant reductions in days per week of alcohol consumption were found between weeks 2 and 3 (2.90 ± 0.28 vs 2.09 ± 0.41; P < 0.05, uncorrected), which were not statistically significant after Bonferroni correction. There were no statistically significant effects for other variables, except for a significant reduction in reaction time in an empathy task.

Conclusions

A significant reduction in days of alcohol consumption was observed 2–3 weeks after ayahuasca intake, but this effect did not survive after Bonferroni correction. The lack of significant effects in alcohol use and other variables may be related to the small sample size and mild/moderate alcohol use at baseline. The present study shows the feasibility of our protocol, paving the way for future larger, controlled studies.
Comparison of patency rates and complications with or without antithrombotic therapy following portal vein stent placement after pancreatic surgery: a systematic review and meta-analysis
Authors: Chen Lin , Wang Ziyan , Dong Liangbo , Wang Zhiwei , Li Zehui , Wang Weibin
Published: May 2024

Background:

Portal vein stent placement is used for portal vein stenosis. However, reports on postpancreatic surgery cases are rare. Whether antithrombotic therapy should be administered remains controversial. In this paper, the authors reviewed current data to evaluate the influence of antithrombosis on stent patency after pancreatic surgery.

Materials and methods:

This systematic review and meta-analysis compared studies in which patients did or did not receive antithrombotic therapy after portal vein stent placement. The authors compared patency after stent placement and complication rate.

Results:

There were 22 (n=207) studies in which patients received antithrombotic therapy and 8 (n=61) in which patients did not receive therapy. Antithrombotic agents, such as aspirin, clopidogrel, heparin, and warfarin, were used. The overall patency rates were similar between the groups (79.2% in the antithrombosis group vs. 88.0% in the nonantithrombosis group). Subgroup analyses included those for the etiology of stenosis, types of antithrombotic agents, acute or chronic stenosis, and causes of stent stenosis. None revealed a significant difference between the patency rates in the antithrombosis and nonantithrombosis groups. However, bleeding complications only occurred in patients who received antithrombotic therapy.

Conclusion:

There is no significant benefit of antithrombotic therapy after portal vein stent placement following pancreatic surgery. Antithrombotic therapy should be performed with caution because it may cause complications, such as bleeding.
Characterization of the gut butyrate-producing bacteria and lipid metabolism in African green monkey as a natural host of simian immunodeficiency virus infection
Authors: Zhao Jingjing , Zhou Xiaojun , Qiu Yefeng , Jia Rui
Published: May 2024

Objective:

Natural hosts of simian immunodeficiency virus (SIV), such as the African green monkey (AGM), possess the ability to avoid acquired immune deficiency syndrome (AIDS) despite lifelong infection. The underlying mechanisms are not completely understood. This study aimed to characterize the gut microbiome and metabolite profiles of different nonhuman primates (NHPs) to provide potential insight into AIDS resistance.

Design and methods:

Fresh feces from Cynomolgus macaques (CMs), and Rhesus macaques (RMs), SIV− AGMs (AGM_N), and SIV+ AGMs (AGM_P) were collected and used for metagenomic sequencing and metabonomic analysis.

Results:

Compared with CMs and RMs, significant decreases in the abundances of Streptococcus, Alistipes, Treponema, Bacteroides, and Methanobrevibacter (P < 0.01), and significant increases in the abundances of Clostridium, Eubacterium, Blautia, Roseburia, Faecalibacterium, and Dialister (P < 0.01) were detected in AGM_N. Compared with AGM_N, a trend toward increased abundances of Streptococcus and Roseburia were found in AGM_P. The levels of metabolites involved in lipid metabolism and butanoate metabolism significantly differed among AGM_P, AGM_N and CM (P < 0.05).

Conclusions:

Our data, for the first time, demonstrated distinguishing features in the abundances of butyrate-producing bacteria and lipid metabolism capacities between different NHP hosts of SIV infection. These findings may correlate with the different characteristics observed among these hosts in the maintenance of intestinal epithelial barrier integrity, regulation of inflammation, and provide insights into AIDS resistance in AGMs.
Interferon-signaling pathways are upregulated in people with HIV with abnormal pulmonary diffusing capacity (DLCO)
Authors: Zhang Michelle , Dai Guorui , Smith Dana L. , Zacco Emanuela , Shimoda Michiko , Kumar Nitasha , Girling Valerie , Gardner Kendall , Hunt Peter W. , Huang Laurence , Lin Jue
Published: May 2024

Objective:

People with HIV (PWH) are at greater risk of developing lung diseases even when they are antiretroviral therapy (ART)-adherent and virally suppressed. The most common pulmonary function abnormality in PWH is that of impaired diffusing capacity of the lungs for carbon monoxide (DLCO), which is an independent risk factor for increased mortality in PWH. Earlier work has identified several plasma biomarkers of inflammation and immune activation to be associated with decreased DLCO. However, the underpinning molecular mechanisms of HIV-associated impaired DLCO are largely unknown.

Design:

Cross-sectional pilot study with PWH with normal DLCO (values greater than or equal to the lower limit of normal, DLCO ≥ LLN, N = 9) or abnormal DLCO (DLCO < LLN, N = 9).

Methods:

We compared the gene expression levels of over 900 inflammation and immune exhaustion genes in PBMCs from PWH with normal vs. abnormal DLCO using the NanoString technology.

Results:

We found that 26 genes were differentially expressed in the impaired DLCO group. These genes belong to 4 categories: 1. Nine genes in inflammation and immune activation pathways, 2. seven upregulated genes that are direct targets of the interferon signaling pathway, 3. seven B-cell specific genes that are downregulated, and 4. three miscellaneous genes. These results were corroborated using the bioinformatics tools DAVID (Database for Annotation, Visualization and Integrated Discovery) and GSEA (Gene Sets Enrichment Analysis).

Conclusion:

The data provides preliminary evidence for the involvement of sustained interferon signaling as a molecular mechanism for impaired DLCO in PWH.
The impact of financial incentives on mental health among adults in HIV care in Lake Zone, Tanzania
Authors: Chitle Pooja , Sheira Lila A. , Katabaro Emmanuel , Winters Solis , Njau Prosper F. , Sabasaba Amon , McCoy Sandra I.
Published: May 2024

Objective:

Depression and anxiety are prevalent among people with HIV (PWH), hindering retention in care. Though economic interventions can improve care engagement and mental health in the general population, this remains understudied among PWH. This study assessed whether financial incentives improve mental health among adult antiretroviral therapy (ART) initiates in Lake Zone, Tanzania.

Design:

Two-arm randomized controlled trial.

Methods:

From 2021 to 2023, 32 clinics were randomized to offer patients monthly financial incentives (22 500 TSH/US$ 10) for ≤six months (conditional on visit attendance) or standard-of-care (SoC) services. We assessed changes in depression (PHQ-2 scores) and anxiety (GAD-2 scores) symptoms at baseline, six, and 12 months. Difference-in-differences effects were used to estimate changes over time by arm using inverse probability of censoring sample weights (IPCW).

Results:

Participants (n = 1990) were 57.3% female; median age was 35.0. Baseline prevalences of depression and anxiety symptoms were 66.2% and 60.4%, respectively, and endline prevalences were 7.8% and 7.6% in the intervention and SoC arms, respectively, with no differences by arm. Using IPCW, the differences in the prevalence of depression and anxiety symptoms in the intervention arm compared to the SoC arm were 2.5 percentage points [95% confidence interval (CI): −3.0, 8.0) and 2.3 percentage points (95% CI: −3.2, 7.9) respectively after six months, and 5.5 percentage points (95% CI: −0.20, 10.8) and 3.8 percentage points (95% CI: −1.5, 9.2) respectively after 12 months.

Conclusion:

Both study arms experienced substantial reductions in poor mental health, primarily within the first six months of care. Financial incentives provided in this study did not significantly augment these downward trends but may improve engagement in care, indirectly improving mental health.
Surgical Outcomes of Revision Orbital Reconstruction in Patients With Inadequate Primary Orbital Fracture Repair
Authors: Choi Yeong A. , Yang Min Kyu , Sa Ho-Seok
Published: May 2024

Objective:

This study aimed to investigate the clinical characteristics of patients with complications following inadequate primary orbital fracture repair and to evaluate surgical outcomes of secondary revision orbital reconstruction.

Methods:

The authors retrospectively reviewed data from 41 patients who underwent revision orbital reconstruction by a single surgeon following complications from primary orbital fracture repair performed elsewhere. Clinical characteristics, including enophthalmos, exophthalmos, diplopia, ocular motility limitation, epiphora, infraorbital hypoesthesia, infection, eyelid malposition, lagophthalmos, hypoglobus, and compressive optic neuropathy, were assessed. Surgical outcomes of revision surgery were evaluated to determine improvements in clinical deficits and postoperative patient satisfaction.

Results:

The most common postoperative complications of primary orbital fracture repair were enophthalmos (n=20/41) and diplopia (n=20/41). The mean time between primary and revision surgeries was 67.2 months (range: 1–276 mo). Revision surgery significantly improved enophthalmos, diplopia (Hess area ratio), epiphora (Munk score), periorbital pain, and exophthalmos (P=0.003, P=0.001, P<0.001, P<0.001, and P=0.007, respectively) compared to the pre-revision state. In addition, 6 patients experienced improved infraorbital hypoesthesia. Among the 41 patients, 23 were very satisfied, 17 were satisfied, and 1 was neutral after revision orbital reconstruction.

Conclusions:

Our study highlights the positive impact of revision orbital reconstruction in addressing complications from inadequate primary orbital fracture repair. Surgeons should consider revision surgery to address clinical deficits following prior surgery, especially when anatomic abnormalities are evident in imaging studies, regardless of the time lapse since the initial surgery or concerns about tissue fibrosis and fat atrophy.
Impaired hippocampal functions underlying memory encoding and consolidation precede robust Aβ deposition in a mouse model of Alzheimer’s disease
Authors: Li Hanyan , Zhao Zhuoyang , Fassini Aline , Lee Han K. , Green Reese J. , Gomperts Stephen N.
Published: May 2024

Current therapeutic strategies for Alzheimer’s disease (AD) target amyloid-beta (Aβ) fibrils and high molecular weight protofibrils associated with plaques, but molecular cascades associated with AD may drive neural systems failure before Aβ plaque deposition in AD. Employing hippocampal electrophysiological recordings and dynamic calcium imaging across the sleep-wake cycle in the APP/PS1 mouse model of AD before Aβ plaques accumulated, we detected marked impairments of hippocampal systems function: In a spatial behavioral task, but not REM sleep, phase-amplitude coupling (PAC) of the hippocampal theta and gamma oscillations was impaired and place cell calcium fluctuations were hyper-synchronized with the theta oscillation. In subsequent slow wave sleep (SWS), place cell reactivation was reduced. These degraded neural functions underlying memory encoding and consolidation support targeting pathological processes of the pre-plaque phase of AD to treat and prevent hippocampal impairments.
Addressing Distribution Mismatch for Effective Semi-Supervised Neuron Segmentation
Authors: Zhang Yanchao , Zhai Hao , Guo Jinyue , Liu Jing , Xie Qiwei , Han Hua
Published: May 2024

Semi-supervised learning offers a cost-effective approach for neuron segmentation in electron microscopy (EM) volumes. This technique leverages extensive unlabeled data to regularize supervised training for more robust predictions of neuron affinities. However, the distribution mismatch between labeled and unlabeled datasets, arising from limited annotations and the diversity of neuronal patterns, impedes the generalization of semi-supervised models. In this paper, we develop a dual-level pipeline to address the inherent mismatch issue and enhance semi-supervised neuron segmentation. At the data level, we propose an unsupervised heuristic to select valuable sub-volumes as labeled data based on distribution similarity in a pretrained feature space, ensuring a representative coverage of neuronal structures. At the model level, we introduce an axial-through mixing strategy into anisotropic neuron segmentation and integrate it into a semi-supervised framework. Building on this, we establish cross-view consistency constraints through intra- and inter-mixing of labeled and unlabeled datasets, which facilitates the learning of shared semantics across distributions while avoiding ambiguity in neuron affinities. Extensive comparative experiments and ablation studies on publicly available datasets demonstrate the effectiveness of the proposed method across different EM modalities and spatial resolutions.