bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial growth on temporary pacemaker leads post-TAVR: pathogen spectrum and clinical implications
Authors: Mousa Basha Mustafa , Al-Kassou Baravan , Gestrich Christopher , Weber Marcel , Beiert Thomas , Bakhtiary Farhad , Nickenig Georg , Zimmer Sebastian , Shamekhi Jasmin
Published: September 2024

Background and objective

Transcatheter aortic valve replacement (TAVR) is an established treatment option for patients with symptomatic severe aortic stenosis across all stages of surgical risk. Rapid pacing during the procedure and the risk for the occurrence of conduction disturbances after TAVR requires the pre-interventional insertion of a temporary pacemaker (TP). However, this approach poses risks, including the risk of infection. For this reason, the following study aimed to investigate microbial growth on temporary pacemaker leads and its association with outcome post-TAVR and to identify associated pathogens and related risk factors.

Methods

A prospective study was conducted including 344 patients undergoing TAVR at the Heart Centre Bonn. Of these, 97 patients did not require TP leads as they already had permanent pacemakers; this group was considered as comparison group. The TP leads of the remaining 247 patients were removed, sonicated, and cultured to investigate bacterial growth over a period of 14 days. Finally, we compared patients without microbial growth (n = 184) and patients with microbial growth (n = 63). The primary endpoint of the study was 30-day all-cause mortality, secondary endpoints were periprocedural infections, the length of the postprocedural hospital stay, 30-day major vascular complications and the 30-day stroke rate.

Results

The majority of cases (74.5%) showed no bacterial growth. In the remaining cases (25.5%), diverse microorganisms were identified, mostly non-pathogenic bacteria. The statistical analysis revealed no significant differences between groups according to microbial growth in terms of 30-day mortality (p = 0.446), postprocedural hospital stay (p = 0.401), periprocedural infections (p = 0.434), 30-day major vascular complications (p = 1.0), and 30-day stroke rate (p = 1.0). Notably, the timing of sheath insertion was significantly associated with microbial growth; sheath placement more than 2 days prior to the procedure was associated with a significantly higher risk of microbial growth (OR: 2.1; 95% CI 1.1–4.3) (p = 0.030).

Conclusions

The presence of temporary leads does not significantly impact clinical outcomes, irrespective of bacterial growth on the lead. However, the timing and duration of sheath placement plays a crucial role in contamination incidence. Thus, temporary leads/sheaths should be placed shortly before the procedure and removed promptly to reduce the risk of contamination/infection.
Integrated analyses reveal two molecularly and clinically distinct subtypes of H3 K27M-mutant diffuse midline gliomas with prognostic significance
Authors: Stegat Lotte , Eckhardt Alicia , Gocke Antonia , Neyazi Sina , Pohl Lara , Schmid Simone , Dottermusch Matthias , Frank Stephan , Pinnschmidt Hans , Herms Jochen , Glatzel Markus , Snuderl Matija , Schweizer Leonille , Thomas Christian , Neumann Julia , Dorostkar Mario M. , Schüller Ulrich , Wefers Annika K.
Published: September 2024

H3 K27M-altered diffuse midline gliomas (DMGs) are highly malignant tumours that arise in the midline structures of the CNS. Most DMGs carry an H3 K27M-mutation in one of the genes encoding for histone H3. Recent studies suggested that epigenetic subgroups of DMGs can be distinguished based on alterations in the MAPK-signalling pathway, tumour localisation, mutant H3-gene, or overall survival (OS). However, as these parameters were studied individually, it is unclear how they collectively influence survival. Hence, we analysed dependencies between different parameters, to define novel epigenetic, clinically meaningful subgroups of DMGs. We collected a multifaceted cohort of 149 H3 K27M-mutant DMGs, also incorporating data of published cases. DMGs were included in the study if they could be clearly allocated to the spinal cord (n = 31; one patient with an additional sellar tumour), medulla (n = 20), pons (n = 64) or thalamus (n = 33), irrespective of further known characteristics. We then performed global genome-wide DNA methylation profiling and, for a subset, DNA sequencing and survival analyses. Unsupervised hierarchical clustering of DNA methylation data indicated two clusters of DMGs, i.e. subtypes DMG-A and DMG-B. These subtypes differed in mutational spectrum, tumour localisation, age at diagnosis and overall survival. DMG-A was enriched for DMGs with MAPK-mutations, medullary localisation and adult age. 13% of DMG-A had a methylated MGMT promoter. Contrarily, DMG-B was enriched for cases with TP53-mutations, PDGFRA-amplifications, pontine localisation and paediatric patients. In univariate analyses, the features enriched in DMG-B were associated with a poorer survival. However, all significant parameters tested were dependent on the cluster attribution, which had the largest effect on survival: DMG-A had a significantly better survival compared to DMG-B (p < 0.001). Hence, the subtype attribution based on two methylation clusters can be used to predict survival as it integrates different molecular and clinical parameters.
GFAP and NfL as fluid biomarkers for clinical disease severity and disease progression in multiple system atrophy (MSA)
Authors: Katzdobler Sabrina , Nübling Georg , Klietz Martin , Fietzek Urban M. , Palleis Carla , Bernhardt Alexander M. , Wegner Florian , Huber Meret , Rogozinski Sophia , Schneider Luisa-Sophie , Spruth Eike Jakob , Beyle Aline , Vogt Ina R. , Brandt Moritz , Hansen Niels , Glanz Wenzel , Brockmann Kathrin , Spottke Annika , Hoffmann Daniel C. , Peters Oliver , Priller Josef , Wiltfang Jens , Düzel Emrah , Schneider Anja , Falkenburger Björn , Klockgether Thomas , Gasser Thomas , Nuscher Brigitte , Haass Christian , Höglinger Günter , Levin Johannes
Published: September 2024

Background

Multiple system atrophy (MSA), an atypical parkinsonian syndrome, is a rapidly progressive neurodegenerative disease with currently no established fluid biomarkers available. MSA is characterized by an oligodendroglial α-synucleinopathy, progressive neuronal cell loss and concomitant astrocytosis. Here, we investigate glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) as fluid biomarkers for differential diagnosis, assessment of clinical disease severity and prediction of disease progression in MSA.

Methods

GFAP and NfL levels were analyzed in plasma and CSF samples of 47 MSA patients as well as 24 Parkinson’s disease (PD) and 25 healthy controls (HC) as reference cohorts. In MSA, biomarker levels were correlated to baseline and longitudinal clinical disease severity (UMSARS scores).

Results

In MSA, GFAP levels in CSF and plasma predicted baseline clinical disease severity as indicated by UMSARS scores, while NfL levels predicted clinical disease progression as indicated by longitudinal changes in UMSARS scores. Cross-sectionally, NfL levels in CSF and plasma were significantly elevated in MSA compared to both PD and HC. Receiver operating curves (ROC) indicated high diagnostic accuracy of NfL for distinguishing MSA from PD (CSF: AUC = 0.97, 95% CI 0.90–1.00; plasma: AUC = 0.90, 95% CI 0.81–1.00).

Discussion

In MSA, GFAP shows promise as novel biomarker for assessing current clinical disease severity, while NfL might serve as biomarker for prediction of disease progression and differential diagnosis of MSA against PD.
Salt-sensitive hypertension in GR mutant rats is associated with altered plasma polyunsaturated fatty acid levels and aortic vascular reactivity
Authors: Verouti S. , Aeschlimann G. , Wang Q. , Del Olmo D. Ancin , Peyter A. C. , Menétrey S. , Winter D. V. , Odermatt A. , Pearce D. , Hummler E. , Vanderriele P. E.
Published: September 2024

In humans, glucocorticoid resistance is attributed to mutations in the glucocorticoid receptor (GR). Most of these mutations result in decreased ligand binding, transactivation, and/or translocation, albeit with normal protein abundances. However, there is no clear genotype‒phenotype relationship between the severity or age at disease presentation and the degree of functional loss of the receptor. Previously, we documented that a GR+/− rat line developed clinical features of glucocorticoid resistance, namely, hypercortisolemia, adrenal hyperplasia, and salt-sensitive hypertension. In this study, we analyzed the GR+/em4 rat model heterozygously mutant for the deletion of exon 3, which encompasses the second zinc finger, including the domains of DNA binding, dimerization, and nuclear localization signals. On a standard diet, mutant rats exhibited a trend toward increased corticosterone levels and a normal systolic blood pressure and heart rate but presented with adrenal hyperplasia. They exhibited increased adrenal soluble epoxide hydroxylase (sEH), favoring an increase in less active polyunsaturated fatty acids. Indeed, a significant increase in nonactive omega-3 and omega-6 polyunsaturated fatty acids, such as 5(6)-DiHETrE or 9(10)-DiHOME, was observed with advanced age (10 versus 5 weeks old) and following a switch to a high-salt diet accompanied by salt-sensitive hypertension. In thoracic aortas, a reduced soluble epoxide hydrolase (sEH) protein abundance resulted in altered vascular reactivity upon a standard diet, which was blunted upon a high-salt diet. In conclusion, mutations in the GR affecting the ligand-binding domain as well as the dimerization domain resulted in deregulated GR signaling, favoring salt-sensitive hypertension in the absence of obvious mineralocorticoid excess.
Gross lesions associated with Sarcocystis miescheriana in a wild boar hunted for human consumption: the importance of trained hunters to ensure animal health surveillance and food safety
Authors: Vieira-Pinto Madalena , Chiesa Francesco , Pires Isabel Cristina Ribeiro , Duarte Carmen Gonzalez , Rubiola Selene
Published: September 2024

Sarcocystis is a genus of protozoa with a worldwide distribution infecting a wide range of animals, including humans. Wild boars can harbor at least two species of Sarcocystis, that is, the zoonotic Sarcocystis suihominis, using humans as definitive hosts, and Sarcocystis miescheriana, for which wild and domestic canids serve as definitive hosts. In Portugal, hunting holds significant economic and social importance, and wild boars are among the most appreciated hunted species. As the consumption of wild boar meat can expose humans to several foodborne pathogens, the presence of trained hunters can make a difference in ensuring animal health surveillance and food safety. Herein, we report the detection of macroscopic cystic lesions associated with S. miescheriana in a wild boar hunted for human consumption, resulting in carcass condemnation. To the best of the authors’ knowledge, the presence of S. miescheriana in wild boar tissues has never been associated with macroscopic pathological alterations before. Although S. miescheriana cannot infect humans, carcasses affected by grossly visible pathological changes must be declared unfit for consumption. Therefore, our finding points out the potential economic damage associated with carcass rejection due to the presence of gross lesions associated with generalized sarcocystosis. Nonetheless, further studies are required to investigate these alterations that currently appear to be occasional findings.
Palliative care in terminally ill advanced chronic liver disease patients
Authors: Pomej Katharina , Masel Eva Katharina , Kreye Gudrun
Published: September 2024

While mortality rates from advanced chronic liver disease (ACLD) are rapidly increasing, patients with an advanced disease stage have a comparable or even higher symptom burden than those with other life-limiting diseases. Although evidence is limited there is increasing recognition of the need to improve care for patients with ACLD; however, there are many limiting factors to providing good palliative care for these patients, including unpredictable disease progression, the misconception of palliative care and end of life care as being equivalent, a lack of confidence in prescribing medication and a lack of time and resources. Health professionals working with these patients need to develop the skills to ensure effective palliative care, while referral to specialized palliative care centers should be reserved for patients with complex needs. Basic palliative care, along with active disease management, is best delivered by the treating hepatologists. This includes discussions about disease progression and advance care planning, alongside the active management of disease complications. Liver disease is closely associated with significant social, psychological, and financial burdens for patients and their caregivers. Strategies to engage the discussion in multidisciplinary teams early in disease progression help to ensure addressing these issues proactively. This review summarizes the evidence on palliative care for patients with ACLD, provides examples of current best practice and offers suggestions on how disease-modifying and palliative care can coexist, to ensure that patients do not miss opportunities for quality of life improving interventions.
Management of hip osteoarthritis: harnessing the potential of mesenchymal stem cells—a systematic review
Authors: Giorgino Riccardo , Alessandri Bonetti Mario , Migliorini Filippo , Nannini Alessandra , Vaienti Luca , Peretti Giuseppe Michele , Mangiavini Laura
Published: September 2024

Introduction

Hip osteoarthritis (OA) is a prevalent and debilitating condition, necessitating effective and safe treatment options. This systematic review aims to explore the potential of intra-articular mesenchymal stem cell (MSC) infiltrations as a therapeutic approach for hip OA.

Methods

Following PRISMA guidelines, a systematic review was conducted, encompassing PubMed, Embase, and Cochrane Library databases. Inclusion criteria involved studies focusing on intra-articular MSC injections in patients with hip OA and reporting pain relief as an outcome measure. Quality assessment utilized the Newcastle–Ottawa scale and methodological index for non-randomized studies.

Results

Ten studies were included in the review, exhibiting varied designs and sample sizes (316 patients). Outcome measures consisted of cartilage repair assessed through MRI and radiographies, pain scores (WOMAC, VAS, NRS), and functional improvements (HOS-ADL, OHS, FRI, PDQQ, LEFS). The studies reported favorable improvements in functional scores, pain relief, and cartilage repair/radiographic findings, with minimal reported adverse events.

Conclusions

Intra-articular MSC infiltrations demonstrate promise as an effective and safe therapeutic intervention for managing hip OA, offering pain relief and functional enhancements. Nevertheless, limited high-quality studies and outcome measure variations underscore the need for further research to establish definitive treatment guidelines. Future investigations should address optimal MSC utilization, long-term outcomes, and potential complications to ensure the success of MSC-based therapies for hip OA management, ultimately improving patient outcomes. The findings provide valuable insights into the potential of MSC-based treatments for hip OA, advocating further rigorous research in this field.

Trial Registration

The protocol was registered on PROSPERO database (CRD42023436973).
A comparison of climate drivers’ impacts on silage maize yield shock in Germany
Authors: Stainoh Federico , Moemken Julia , Gouveia Celia M. , Pinto Joaquim G.
Published: September 2024

Extreme weather events have become more frequent and severe with ongoing climate change, with a huge implication for the agricultural sector and detrimental effects on crop yield. In this study, we compare several combinations of climate indices and utilized the Least Absolute Shrinkage and Selection Operator (LASSO) to explain the probabilities of substantial drops in silage maize yield (here defined as “yield shock” by using a 15th percentile as threshold) in Germany between 1999 and 2020. We compare the variable importance and the predictability skill of six combinations of climate indices using the Matthews Correlation Coefficient (MCC). Finally, we delve into year-to-year predictions by comparing them against the historical series and examining the variables contributing to high and low predicted yield shock probabilities. We find that cold conditions during April and hot and/or dry conditions during July increase the chance of silage maize yield shock. Moreover, a combination of simple variables (e.g. total precipitation) and complex variables (e.g. cumulative cold under cold nights) enhances predictive accuracy. Lastly, we find that the years with higher predicted yield shock probabilities are characterized mainly by relatively hotter and drier conditions during July compared to years with lower yield shock probabilities. Our findings enhance our understanding of how weather impacts maize crop yield shocks and underscore the importance of considering complex variables and using effective selection methods, particularly when addressing climate-related events.
Do Children Cause the Cognitive Stimulation they Receive? Modelling the Direction of Causality
Authors: Starr Alexandra , Oginni Olakunle , von Stumm Sophie
Published: September 2024

We tested the directionality of associations between children’s early-life cognitive development and the cognitive stimulation that they received from their parents. Our sample included up to 15,314 children from the Twins Early Development Study (TEDS), who were born between 1994 and 1996 in England and Wales and assessed at ages 3 and 4 years on cognitive development and cognitive stimulation, including singing rhymes, reading books, and playing games. Using genetically informative cross-lagged models, we found consistent, bidirectional effects from cognitive development at age 3 to cognitive stimulation at age 4, and from cognitive stimulation at age 3 to cognitive development at age 4. These cross-lagged longitudinal effects were largely explained by underlying common genetic and shared environmental factors, rather than reflecting causal mechanisms. Our findings emphasize the active role that children play in constructing their own learning experiences.
Feasibility study on virtual reality-based training for skin cancer screening: Bridging the gap in dermatological education
Authors: Mergen Marvin , Will Lisa , Graf Norbert , Meyerheim Marcel
Published: September 2024

Despite growing interest in the inclusion of virtual reality (VR) in medical education, its full potential for immersive and interactive training remains underutilized, particularly in dermatology. As part of a multidisciplinary project, we tested the feasibility of integrating a VR training scenario for a complete skin cancer screening into the curriculum with 58 medical students. The evaluation focused on simulation usability, cognitive task load, immersion, change in perceived competence, suitability, and cybersickness using established and adapted questionnaires. Participants reported rather high levels of system usability and immersion and medium cognitive task load. Self-assessed competence in performing a skin cancer screening increased significantly after the training simulation.

Prior skin cancer screening experience correlated positively with self-assessed competence and theoretical knowledge, which themselves were neither related to gender nor age. Age correlated negatively with perceived usability and immersion, enjoyment of learning during the simulation and assessed appropriateness of the simulation to learn a dermatological full-body examination while being positively correlated with perceived cybersickness. Gender was significantly associated with the need for technical help during the simulation and openness to new technologies.

As a blueprint of a feasibility evaluation, this study can contribute to further refinement of the presented and relatable VR applications in medical curricula.
An integrated strategy for pathogen surveillance unveiled Xylella fastidiosa ST1 outbreak in hidden agricultural compartments in the Apulia region (Southern Italy)
Authors: Cornara Daniele , Boscia Donato , D’Attoma Giusy , Digiaro Michele , Ligorio Angela Maria , Loconsole Giuliana , Minutillo Serena Anna , Montilon Vito , Palmisano Francesco , Ragone Gianvito , Silletti Maria Rosaria , Verrastro Vincenzo , Zaza Claudio , Saponari Maria
Published: September 2024

Annual surveillance programs for the plant pathogenic bacterium Xylella fastidiosa are implemented in Europe as part of the preventive phytosanitary strategies enforced to face the emergence of the detrimental infections reported in olives in southern Italy. The programs include inspections and sampling of host plants by prioritizing those showing suspicious symptoms or those known to be highly susceptible to different strains and subspecies of the bacterium. In the framework of these programs numerous outbreaks have been unraveled, with several strains and subspecies found to infect a relatively large host range in France, Spain, Portugal and Italy. Here we report the results of an integrated surveillance approach implemented in the Apulia Region (southern Italy), where a conventional survey program on host plants is complemented by monitoring and testing for X. fastidiosa the insect vectors. In the framework of this program, bacterium-positive spittlebugs were intercepted in the Xylella-free area of the region, close to one of the most relevant Italian table grape production district. Such findings prompted further investigation to identify the bacterial reservoir in the host plants. Almond and grapevine were found to be the most frequently infected hosts, with infections caused by isolates of X. fastidiosa subspecies fastidiosa ST1. Investigations are ongoing to assess the extent and history of the outbreak, to assess and estimate the potential impacts, and define the best options for its containment.
Early sex identification by leaflet distance in plantlets of Cycas revoluta
Authors: De Luca Ylenia , Cozzolino Salvatore , Cristaudo Antonia , Widmer Alex , Cafasso Donata
Published: September 2024

In dioecious plants, the process of sex determination usually occurs during the reproductive stage. However, it can be challenging to determine the sex of long-lived plants with long generation times. This is true for Cycas revoluta, which produces toxic seeds in female plants, leading to a preference for male plants in public green spaces. In this study we aim to identify a morphological trait that can be used to distinguish between the sexes in C. revoluta at a very early stage of plant growth. We sampled C. revoluta seedlings/plantlets at three different early growth stages and identified the sex of individuals by PCR amplification of a male-specific molecular marker. On the same plants, we measured morphological traits, including the distance between leaflets on the leaf rachis, perimeter, area, number of indents, and leaf complexity, and evaluated their correlation with the sex of the individuals. Among all measured traits, the medium distance between leaflets on the leaf rachis was found to be a sexually dimorphic morphological trait in Cycas plantlets in all three growth stages. In particular, the distance between leaflets on the leaf rachis in the upper part of the leaf in the first stage revealed no overlap between the sexes. Whenever available, morphological traits for sex differentiation in greenhouses and plant nurseries can represent a rapid and economic tool when coupled with automatized image recognition systems.
The Kynurenine Pathway in Gut Permeability and Inflammation
Authors: Kearns Rowan
Published: September 2024

The gut-brain axis (GBA) is a crucial communication network linking the gastrointestinal (GI) tract and the central nervous system (CNS). The gut microbiota significantly influences metabolic, immune, and neural functions by generating a diverse array of bioactive compounds that modulate brain function and maintain homeostasis. A pivotal mechanism in this communication is the kynurenine pathway, which metabolises tryptophan into various derivatives, including neuroactive and neurotoxic compounds. Alterations in gut microbiota composition can increase gut permeability, triggering inflammation and neuroinflammation, and contributing to neuropsychiatric disorders. This review elucidates the mechanisms by which changes in gut permeability may lead to systemic inflammation and neuroinflammation, with a focus on the kynurenine pathway. We explore how probiotics can modulate the kynurenine pathway and reduce neuroinflammation, highlighting their potential as therapeutic interventions for neuropsychiatric disorders. The review integrates experimental data, discusses the balance between neurotoxic and neuroprotective kynurenine metabolites, and examines the role of probiotics in regulating inflammation, cognitive development, and gut-brain axis functions. The insights provided aim to guide future research and therapeutic strategies for mitigating GI complaints and their neurological consequences.
Flexible magnesium-ion-conducting solid poly-blend electrolyte films for magnesium-ion batteries
Authors: Nayak Pradeep , Ismayil  , Sudhakar Y. N. , Murari M. S.
Published: September 2024

Solid biodegradable polymer electrolyte systems are considered the optimal choice for energy storage devices because they are both cost-effective and energy-efficient. A solid blend polymer electrolyte (SBPE) membrane capable of transporting magnesium ions was prepared using a mixture of 70 wt% methylcellulose, 30 wt% chitosan, and varying wt% magnesium perchlorate salt. X-ray diffraction analysis revealed an increase in the amorphous nature caused by the inclusion of Mg(ClO4)2 salt in the polymer blend matrix. A Fourier transform infrared spectroscopy study of samples containing varying salt concentrations revealed secondary interactions between polymer segments and salt, which provides the basis for energy density. Moreover, through impedance analysis, it was determined that the bulk resistance decreased with increasing salt concentration. The SBPE containing 30 wt% magnesium perchlorate exhibited the highest ionic conductivity, with a value of 2.49 × 10–6 S cm−1. A comprehensive evaluation of the ion transport parameters, including mobility, carrier density, and diffusion, was conducted for the prepared electrolyte samples. Notably, an ionic transference number (tion) of approximately 0.83 was observed for the SBPE sample with 30 wt% magnesium salt, indicating ions’ prevalence as the system’s primary charge carriers. Electrochemical analyses demonstrated that the SBPE with the highest ion conductivity possessed an electrochemical stability window (ESW) of 1.92 V. Additionally, the thermal characteristics of the samples were evaluated using thermogravimetric analysis (TGA) to assess the thermal stability of the electrolyte. Finally, the highest conducting polymer electrolyte was employed to construct a primary magnesium battery, and its discharge profile with different cathode materials was studied. Based on these findings, the current study suggests an environmentally friendly, biodegradable, and economically viable electrolyte option suitable for separator cum electrolytes in magnesium-ion batteries.
Unlocking the Potential of Retro-Inverso (RI) Peptides as Future Drug Candidates
Authors: Al Musaimi Othman
Published: September 2024

Background

With the rising demand for peptide-based drugs, enhancing their stability against proteolytic degradation has become a critical challenge. Strategies to improve peptide stability include cyclization, substitution of L-amino acids with D-amino acids, incorporation of β-amino acids, and various formulation techniques. An innovative approach involves modifying the peptide backbone by reversing the amide bond direction and inverting the stereochemistry of amino acids in the same segment. This approach results in the formation of retro-inverso peptides, which offer increased stability, permeability, and cellular uptake.

Purpose

The aim of this review is to provide a comprehensive analysis of retro-inverso peptides, focusing on their concept, synthesis, and applications as potential therapeutic agents, drug delivery systems, and in aesthetic applications.

Methods

The review explores the theoretical underpinnings of retro-inverso peptide design and its application to both linear and cyclic peptides. The synthesis strategies of retro-inverso peptides are discussed in detail, along with their formulation and practical utility in various biomedical fields.

Results

Retro-inverso peptides show promise in enhancing peptide stability and improving biological properties such as permeability and cellular uptake. Their unique structure offers advantages in drug development and potential as therapeutic agents or drug carriers.

Conclusion

Retro-inverso peptides represent a valuable strategy for overcoming the limitations of conventional peptides, especially regarding stability and bioavailability. This review highlights their potential in therapeutic development and other applications, reinforcing the importance of continued research and innovation in peptide chemistry.
l-Lactate dehydrogenase from Cyanidioschyzon merolae shows high catalytic efficiency for pyruvate reduction and is inhibited by ATP
Authors: Yamamoto Mai , Osanai Takashi , Ito Shoki
Published: September 2024

l-Lactate is a commodity chemical used in various fields. Microorganisms have produced l-lactate via lactic fermentation using saccharides derived from crops as carbon sources. Recently, l-lactate production using microalgae, whose carbon source is carbon dioxide, has been spotlighted because the prices of the crops have increased. A red alga Cyanidioschyzon merolae produce l-lactate via lactic fermentation under dark anaerobic conditions. The l-lactate titer of C. merolae is higher than those of other microalgae but lower than those of heterotrophic bacteria. Therefore, an increase in the l-lactate titer is required in C. merolae. l-Lactate dehydrogenase (l-LDH) catalyzes the reduction of pyruvate to l-lactate during lactic fermentation. C. merolae possesses five isozymes of l-LDH. The results of previous transcriptome analysis suggested that l-LDHs are the key enzymes in the lactic fermentation of C. merolae. However, their biochemical characteristics, such as catalytic efficiency and tolerance for metabolites, have not been revealed. We compared the amino acid sequences of C. merolael-LDHs (CmLDHs) and characterized one of the isozymes, CmLDH1. BLAST analysis revealed that the sequence similarities of CmLDH1 and the other isozymes were above 99%. The catalytic efficiency of CmLDH1 under its optimum conditions was higher than those of l-LDHs of other organisms. ATP decreased the affinity and turnover number of CmLDH1 for NADH. These findings contribute to understanding the characteristics of l-LDHs of microalgae and the regulatory mechanisms of lactic fermentation in C. merolae.
Optimizing photosynthetic light-harvesting under stars: simple and general antenna models
Authors: Chitnavis Samir , Gray Callum , Rousouli Ifigeneia , Gillen Edward , Mullineaux Conrad W. , Haworth Thomas J. , Duffy Christopher D. P.
Published: September 2024

In the next 10–20 years, several observatories will aim to detect the signatures of oxygenic photosynthesis on exoplanets, though targets must be carefully selected. Most known potentially habitable exo-planets orbit cool M-dwarf stars, which have limited emission in the photosynthetically active region of the spectrum (PAR, $$400< \lambda < 700$$

400
<
λ
<
700

nm) used by Earth’s oxygenic photoautotrophs. Still, recent experiments have shown that model cyanobacteria, algae, and non-vascular plants grow comfortably under simulated M-dwarf light, though vascular plants struggle. Here, we hypothesize that this is partly due to the different ways they harvest light, reflecting some general rule that determines how photosynthetic antenna structures may evolve under different stars. We construct a simple thermodynamic model of an oxygenic antenna-reaction centre supercomplex and determine the optimum structure, size and absorption spectrum under light from several star types. For the hotter G (e.g. the Sun) and K-stars, a small modular antenna is optimal and qualitatively resembles the PSII-LHCII supercomplex of higher plants. For the cooler M-dwarfs, a very large antenna with a steep ’energy funnel’ is required, resembling the cyanobacterial phycobilisome. For the coolest M-dwarfs an upper limit is reached, where increasing antenna size further is subject to steep diminishing returns in photosynthetic output. We conclude that G- and K-stars could support a range of niches for oxygenic photo-autotrophs, including high-light adapted canopy vegetation that may generate detectable bio-signatures. M-dwarfs may only be able to support low light-adapted organisms that have to invest considerable resources in maintaining a large antenna. This may negatively impact global coverage and therefore detectability.
Assessing the Psychometric Properties of Quality Experience in Undergraduate Research Using Item Response Theory
Authors: Hu Tien-Ling , Valdivia Dubravka Svetina
Published: September 2024

Undergraduate research, recognized as one of the High-Impact Practices (HIPs), has demonstrated a positive association with diverse student learning outcomes. Understanding the pivotal quality factors essential for its efficacy is important for enhancing student success. This study evaluates the psychometric properties of survey items employed to gauge the quality of undergraduate research, including alignment with Kuh and O’Donnell’s (2013) eight HIP characteristics, alongside assessments of reliability, validity, and generalizability across demographic groups. The study assesses the validity and reliability of these measures at both the scale and item levels using data from the National Survey of Student Engagement’s (NSSE) HIP Quality Topical Module. The methodological approaches employed include Exploratory Factor Analysis, Parallel Analysis, Item Response Theory, and Differential Item Functioning (DIF). Our findings uncover a misalignment between NSSE’s HIP Quality module items and HIP characteristics, leading to the identification of seven subscales instead of eight. Nevertheless, four subscales—Reflective and Integrative Learning, Real-World Applications, Interactions with Others, and High-Performance Expectations—emerge as valid indicators of undergraduate research experiences. While specific items yield valuable insights at the item level, refinement is recommended for others. Despite the identification of two items exhibiting DIF, their negligible effect sizes suggest that major revisions are unwarranted solely on DIF grounds. This study offers recommendations for item refinement, including the incorporation of new items, wording updates, and tailored utilization of assessment tools within educational institutions. These recommendations are intended to empower educators and researchers to effectively capture the quality dimensions of students’ undergraduate research experiences, thereby fostering their academic success.
Urban scavenging: vertebrates display greater sensitivity to land-cover and garden vegetation cover than invertebrates
Authors: Walker Jack R. , Evans Karl L. , Jeffreys Rachel M. , Pahlevani Mani , Parr Catherine L.
Published: September 2024

Scavenging removes carrion or littered food waste from the environment, promoting nutrient cycling, and reducing waste management costs. These ecosystem services are important in urban environments, where high human population densities result in increased littered food waste. It is unclear how the magnitude of scavenging across urban-rural gradients is influenced by agent, land-cover type, and patch size. We investigated scavenging provision by vertebrates and invertebrates across a gradient of urbanisation, based on impervious surface cover, in woodlands and gardens in Liverpool, UK. The percentage dry weight loss of bait after 48 h, deployed within vertebrate exclusion cages or exposed to vertebrates and invertebrates, was used to quantify scavenging provision. General linear mixed effects models were used to assess the relative contributions of vertebrates and invertebrates across an urban-rural gradient, variation in scavenging between woodlands and gardens, and the effects of semi-natural vegetation cover on scavenging in gardens. We consider patch size as a preliminary assessment of how fragmentation influences scavenging. Vertebrates contributed substantially more to scavenging than invertebrates across the urbanisation gradient. Vertebrate scavenging was greater in woodlands than gardens, while invertebrate scavenging remained consistent. Scavenging increased with patch size in gardens, but not woodlands. Vertebrate scavenging increased with patch size and garden semi-natural vegetation cover. Urban woodlands and gardens make important contributions to scavenging-mediated ecosystem services. There is a need to increase the cover of semi-natural vegetation in gardens to increase their contributions, and protect and expand woodlands, especially in areas with a high demand for scavenging-mediated ecosystem services.
Size Effect on the Ductile Fracture of the Aluminium Alloy 2024-T351
Authors: Šebek F. , Salvet P. , Boháč P. , Adámek R. , Věchet S. , Návrat T. , Zapletal J. , Ganjiani M.
Published: September 2024

Background

Reliably calibrated criteria are needed for an accurate prediction of fracture of various components. However, there is not always a sufficient amount of material available. Therefore, miniature testing provides an alternative that is researched together with the following calibration of the ductile fracture criteria and investigating the size effect.

Objective

The aim is to design miniature testing equipment and specimens for tensile testing, which covers various stress states. This is supplemented by the small punch test, which has the same specimen thickness, taken from the literature to broaden the portfolio for calibration. The second part deals with conducting the finite element analysis, which provided a basis for the calibration of the phenomenological ductile fracture criterion applicable to crack-free bodies to indicate the crack initiation.

Methods

The steel frame to test thin specimens is designed with optical measurement of deformations. The finite element method is used, within Abaqus and user subroutines, to simulate the tests to obtain the variables needed for the calibration. In addition, the calibration of the criterion using machine learning is explored.

Results

The feasibility of the proposed experimental program is tested on the aluminium alloy 2024-T351. Moreover, the numerical simulations, which showed a good match with experiments in terms of force responses, adds to the knowledge of modelling in the scope of continuum damage mechanics.

Conclusions

The presented results provide a material basis for the aluminium alloy studied on a lower scale, while they broaden the testing possibilities and analyses the calibration strategies for the best failure predictability possible.
Investigating the Microarchaeological Record at Underwater Sites: Operating an On-Site Laboratory During the Antikythera Shipwreck Excavation
Authors: Ogloblin Ramirez Isaac , Simosi Angeliki , Baumer Lorenz , Manousos Orestes , Birchler Emery Patrizia , Pönitz Timothy , Sotiriou Alexandros
Published: September 2024

Underwater excavations require an immense amount of logistics and have inherent time limitations. Underwater challenges such as nitrogen toxicity, underwater color change, and dive time limits increase with working depths, affecting the interpretation of archaeological contexts. Thus, underwater excavations involve methods and approaches to extract the maximum information from small areas while providing a comprehensive understanding of the archaeological record. Here, we present the benefits of using an on-site laboratory comprising a microscope, binocular microscope, Fourier transform infrared spectrometer and blue light inspection device. Three case studies are presented, focusing on the identification of stratigraphic boundaries, as well as the preservation and identification of archaeological materials. The results show a complex stratigraphic sequence containing seven layers divided into four mineralogical units: (1) Calcite, (2) Calcite and aragonite, (3) Aragonite, and (4) Dolomite. Additionally, the use of an on-site laboratory is effective in preventing the misidentification of archaeological materials, which could affect the final interpretation of the archaeological site (e.g., glass, lead, bone), and enabling the identification of materials invisible to the naked eye, such as opaline phytoliths. In the case of the Antikythera shipwreck, the on-site laboratory facilitated the examination of stratigraphy and quality of the archaeological context while streamlining excavation practices and documentation. Furthermore, the on-site laboratory allowed for the assessment of material preservation and provide crucial insights to inform post-excavation treatments and analysis of artifacts.
Learning to be overprecise
Authors: Merkle Christoph , Schreiber Philipp
Published: September 2024

We replicate and extend two studies on the dynamics of overconfidence among financial professionals. Using 20 years of data from the ZEW Financial Market Survey with over 40,000 individual forecasts of confidence intervals, we document that participants are overprecise during the entire time period with no evidence of learning on the aggregate. We confirm that professionals update in a Bayesian manner after hits and misses by contracting or expanding their confidence intervals, respectively. However, this updating is insufficient to reach proper calibration. We cannot confirm other predictions of a Bayesian model. An explanation based on self-attribution bias fits the data better.
3D UHR seismic and back-scattering analysis for seabed and ultra-shallow subsurface classification
Authors: Ha Jiho , Shin Jungkyun , Lim Kyoungmin , Um In-Kwon , Yi Boyeon
Published: September 2024

Recently, the seabed classification method based on back-scattering data of multi-beam echo-sounder (MBES) is widely used to analyze the distribution of seabed sediment. Although various analysis methods for seabed classification using multi-spectral MBES have been developed, they are limited in securing penetration depth to consider the characteristics of the shallow subsurface structure. In this study, the seabed and ultra-shallow subsurface classification was performed by comparative analysis of box corer sampling, back-scattering, and 2D/3D ultra-high-resolution (UHR) seismic data obtained from Yeongil Bay, South Korea. We proposed a process for seismic ultra-shallow subsurface classification by the segmentation of the primary seabed reflection wavelet and the amplitude analysis. The seabed-reflected amplitude and back-scattering intensity showed similar mapping trends in the relatively homogeneous and thick surface sediment. On the other hand, it was confirmed that back-scattering data and seabed-reflected amplitude show different patterns when the subsurface structure is related to the seabed surface. It is presumed that because seismic data containing relatively low-frequency components have a deeper penetration depth than MBES, they contain more characteristics of the ultra-shallow subsurface than back-scattering data. These were determined that back-scattering has advantages in representing acoustic anomaly distribution by surface sediment type, and seabed-reflected amplitude is advantageous for representing sediment type by ultra-shallow subsurface. In particular, these results were well shown when the surface sediment thinly covered the rocky bottom. Therefore, it is necessary not only to analyze the back-scattering of MBES but also the ultra-shallow subsurface features through seismic data for valid seabed classification.
The idea marketplace: Diversity, social capital, and innovation
Authors: Heusler Andreas H. , Foutz Natasha Z. , Spann Martin , Stich Lucas
Published: September 2024

Firms increasingly leverage idea markets, where participants (such as employees) generate, improve, and evaluate ideas on a collaborative digital platform. Different participants contribute differently to the ideation process, some generating high quality ideas while others initiating discussion threads and commenting on the ideas to further enhance the ideas’ quality. Such diverse contributions may be importantly influenced by the participants’ diverse social capital—resource access and status—in their pre-existing network. We theorize this relationship and further test our hypotheses by conducting two idea market studies, one involving only a firm’s employees (Study 1: closed innovation) and the other further incorporating non-employees (Study 2: open innovation). We show that the higher quality ideas are generated by the participants with greater resource access, whereas continued engagement, including contributing larger quantities of ideas, discussion threads, and comments, stems from those with higher status. These findings have important implications for ideator recruitment and idea market design.
Serum Selenium Levels and Lipid Profile: A Systematic Review and Meta-analysis of Observational Studies
Authors: Mazaheri-Tehrani Sadegh , Abhari Amir Parsa , Ostadsharif Negar , Shekarian Arman , Vali Mahshad , Saffari Elahe , Anaraki Kasra Talebi , Haghighatpanah Mohammad Ali , Fakhrolmobasheri Mohammad , Kieliszek Marek
Published: September 2024

Selenium is a trace element with pivotal roles in metabolic processes. Studies suggested that selenium deficiency could lead to impaired lipid profiles. However, inconsistent results have been reported regarding the association between serum selenium concentrations and lipid profile (triglycerides, LDL, HDL, VLDL, and total cholesterol). Thus, we aimed to review the correlation between them. A systematic literature search was conducted in PubMed, Embase, Web of Science, Scopus, and Google Scholar until 31 December 2023. The relevant correlation coefficients were used as desired effect sizes to assess the correlation between selenium level and lipid profile. Among 8291 records found in the primary search, 47 and 34 articles were included in the systematic review and meta-analysis, respectively. All included studies were observational investigations and had acceptable quality. Our results failed to reach strong evidence supporting the correlation between serum selenium level and lipid profiles, except for HDL, which showed a weak correlation among both adults (r = 0.1 [0.03:0.17]; I2 = 71%) and pediatrics (r = 0.08 [0.03:0.14]; I2 = 38%). Subgroup analyses based on gender did not reveal a significant or strong correlation with selenium levels (except for total cholesterol in males (r = 0.12 [0.01:0.22]; I2 = 52%)). The results did not change after the sensitivity analysis. Although some previous studies have suggested that selenium deficiency could lead to impaired lipid profile, the findings of this study indicate no strong correlation between serum selenium levels and lipid profile.