bluuebunny/crossref_metadata_2025 huggingface dataset:
Bilateral thalamic infarct involving artery of Percheron: a case report
Authors: Bhattarai Himal Bikram , Dahal Subid Raj , Uprety Manish , Bhattarai Madhur , Bhattarai Aseem , Oli Rabindra , Devkota Sijuka , Sah Sanjit Kumar , Parajuli Suraj , limbu Chandra Prakash
Published: September 2023

Introduction and importance:

The thalamus and the midbrain have marked variations and overlapping in their blood supply; one of those variations is the artery of Percheron. Artery of Percheron occlusion is a rare cause of infarction in the bilateral thalamus and midbrain.

Case presentation:

In this case, a 60-year-old female with chronic hypertension presented with unconsciousness, motor impairments, and oculomotor disorders.

Clinical discussion:

Due to highly variable clinical manifestations and possible negative findings during initial imaging, these conditions are often overlooked, causing delays in therapeutic intervention and leading to bad patient prognosis. Various imaging techniques can be used for diagnosis and treatment should be started early. The treatment aims to promote recanalization as soon as possible and prevent future episodes. The involvement of the midbrain is unfavourable.

Conclusion:

Early clinical assessment and neuroimaging are vital for timely diagnosis and early administration of therapeutic measures for better patient prognosis.
Bilateral laparosocopic lateral lymph node dissection by the totally extraperitoneal approach after intersphincteric resection of the lower rectum: report of a case
Authors: Nitta Toshikatsu , Kataoka Jun , Ishii Masatsugu , Ueda Yasuhiko , Ohta Masato , Horiguchi Kohei , Taki Masaki , Senpuku Sadakatsu , Matsutani Ayumi , Ishibashi Takashi
Published: September 2023

Introduction and Importance:

Lateral lymph node dissection (LLND) for recurrent lateral pelvic lymph node metastasis could be the only surgical treatment to improve its prognosis, but is difficult and challenging technically.

Case Presentation:

A 75-year-old Japanese man who underwent a radical laparoscopic intersphincteric resection to treat double lower rectal cancer. Computed tomography and MRI showed lower rectal wall thickening and bilateral lateral lymph node swelling. The authors scheduled and performed the LLND for recurrent lateral pelvic lymph nodes after ISR by the totally extraperitoneal (TEP) approach. The bottom of the obturators lymph node (#263D) were positive for metastasis histologically.

Clinical Discussion:

The TEP approach is an especially effective option for the treatment of bilateral LLND.

Conclusion:

Herein, the authors introduce our surgical technique: successful challenging treatment of the LLND by the TEP approach after intersphincteric resection of the lower rectum.
Platelet-rich plasma versus corticosteroid: a randomized controlled trial on tennis elbow patients resistant to nonsurgical treatments
Authors: Sayadi Shahram , Shahbazi Parmida , Najafi Arvin , Ochi Fatemeh , Jafarabady Kyana , Rezaei Mohammad M. , Azarsina Salman
Published: September 2023

Background:

Although some studies on tennis elbow indicate corticosteroid (CS) effectiveness in the short term, according to the role of race, this study evaluates the efficacy of platelet-rich plasma (PRP) compared with CS for a more cost-effective treatment.

Methods:

This randomized controlled trial included 30 positive-resisted wrist extension patients with a minimum five visual analog scale (VAS) pain score. Participants were randomly assigned to treatment or control groups via computer-generated randomization and were matched for baseline and clinical characteristics. Cases received either 40 mg of prednisolone acetate or 2 ml of PRP, followed for 1 month. VAS and Disabilities of the Arm, Shoulder, and Hand (DASH) scores were the primary outcomes.

Results:

The median VAS and the mean DASH scores had a statistically significant difference in the PRP and CS groups before and after injection (P<0.001).

The mean DASH difference between preinjection and follow-up time in the PRP and CS groups was 59.72±14.17 and 43.16±10.87, respectively, with a mean difference of 16.55 (95% CI 7.10–26.00) and a significant difference (P=0.001).

The mean VAS pain score difference in preinjection and follow-up time had a statistically significant difference between the PRP and CS groups (P=0.026), and the mean VAS pain score difference in the CS group was 6.46±1.50 and 7.73±0.96 in the PRP group.

Conclusion:

In conclusion, larger studies with parallel groups and more diverse CS doses and types with baseline matching are needed to confirm the short-term benefits of PRP. Investigating the effects of different CS doses using ultrasound techniques is recommended.
Remyelination in multiple sclerosis, along with its immunology and association with gut dysbiosis, lifestyle, and environmental factors
Authors: Prajjwal Priyadarshi , Inban Pugazhendi , Natarajan Balaganesh , Gadam Srikanth , Marsool Mohammed D.M. , Tariq Halla , Paras Paras , Vora Neel , Al-Aish Sandra T. , Marsool Ali D.M. , Amir Hussin Omniat
Published: September 2023

Multiple sclerosis (MS) is a chronic inflammatory disease that damages the myelin sheath around the axons of the central nervous system. While there are periods of inflammation and remyelination in MS, the latter can sometimes be insufficient and lead to the formation of lesions in the brain and spinal cord. Environmental factors such as vitamin D deficiency, viral or bacterial infections, tobacco smoking, and anxiety have been shown to play a role in the development of MS. Dysbiosis, where the composition of the microbiome changes, may also be involved in the pathogenesis of MS by affecting the gut’s microbial population and negatively impacting the integrity of the epithelia. While the cause of MS remains unknown, genetic susceptibility, and immunological dysregulation are believed to play a key role in the development of the disease. Further research is needed to fully understand the complex interplay between genetic, environmental, and microbial factors in the pathogenesis of MS.
Early Outcomes of Different Reconstruction Procedures in Radical Distal Gastrectomy: A Retrospective Propensity Score Matching Study
Authors: Yu Zhiyuan , Zhao Xudong , Gao Yunhe , Gao Jingwang , Li Peiyu , Liu Na
Published: September 2023

Objective:

To evaluate the short-term effects of Billroth I (B-I), Billroth Ⅱ (B-Ⅱ), Billroth Ⅱ+Braun (B-B), and Roux-en-Y (R-Y) reconstruction procedures in radical distal gastrectomy using propensity score matching (PSM).

Materials and Methods:

The clinical data of 1994 patients who underwent radical distal gastrectomy in the past 10 years were retrospectively analyzed. Subsequently, PSM analyses were performed 3 times on the 4 reconstruction procedures, and the matching capacity was set to 0.01. Data regarding control variables and outcome indicators obtained using PSM were compared and analyzed.

Results:

Compared with the other reconstruction procedures, patients in the B-I group had shorter operation time (P=0.002), fewer abdominal drainage tubes (P<0.001), and a lower risk of postoperative gastroparesis (P=0.001) and gastrointestinal bleeding (P=0.034), but tended to experience a longer postoperative indwelling time of bladder catheter (P<0.001), gastrointestinal decompression (P<0.001), fasting (P=0.001), and hospital stays (P=0.005). The B-B group tended to have fewer applications of the abdominal drainage tube (P=0.014), a lower risk of postoperative gastrointestinal fistula (P=0.040), shorter postoperative time of gastrointestinal decompression (P=0.043), fasting (P<0.001), and a shorter hospital stay (P<0.001) than the R-Y group. Furthermore, the B-B group had a shorter postoperative time for gastrointestinal decompression (P=0.014) and fasting (P<0.001) than the B-Ⅱ group.

Conclusion:

Billroth I reconstruction has the advantages of simple operation, short operative time, and few early complications, but tends to result in a long recovery time during postoperative hospitalization. The B-B operation is associated with faster postoperative recovery than the R-Y or B-Ⅱ operation.
Experimental light at night explains differences in activity onset between urban and forest great tits
Authors: McGlade Ciara L. O. , Capilla-Lasheras Pablo , Womack Robyn J. , Helm Barbara , Dominoni Davide M.
Published: September 2023

Artificial light at night (ALAN) is rapidly increasing and so is scientific interest in its ecological and evolutionary consequences. In wild species, ALAN can modify and disrupt biological rhythms. However, experimental proof of such effects of ALAN in the wild is still scarce. Here, we compared diel rhythms of incubation behaviour, inferred from temperature sensors, of female great tits (
Parus major
) breeding in urban and forest sites. In parallel, we simulated ALAN by mounting LED lights (1.8 lx) inside forest nest-boxes, to determine the potentially causal role of ALAN affecting diel patterns of incubation. Urban females had an earlier onset of activity compared to forest females. Experimentally ALAN-exposed forest females were similar to urban females in their advanced onset of activity, compared to unexposed forest birds. However, forest females exposed to experimental ALAN, but not urban females, were more restless at night than forest control females. Our findings demonstrate that ALAN can explain the early activity timing in incubating urban great tits, but its effects on sleep disturbance in the forest are not reflected in urban females. Consequently, future research needs to address potential effects of ALAN-induced timing on individual health, fitness and population dynamics, in particular in populations that were not previously affected by light pollution.
The welfare problems of wide-ranging Carnivora reflect naturally itinerant lifestyles
Authors: Bandeli Miranda , Mellor Emma L. , Kroshko Jeanette , Maherali Hafiz , Mason Georgia J.
Published: September 2023

Carnivora with naturally small home ranges readily adjust to the evolutionarily new environment of captivity, but wider-ranging species seem prone to stress. Understanding why would advance both collection planning and enclosure design. We therefore investigated which aspects of wide-ranging lifestyles are key. We identified eight correlates of home range size (reflecting energetic needs, movement, intra-specific interactions, and itinerant lifestyles). We systematically assessed whether these correlates predict welfare better than range sizeper se, using data on captive juvenile mortality (from 13 518 individuals across 42 species) and stereotypic route-tracing (456 individuals, 27 species). Naturally itinerant lifestyles (quantified via ratios of daily to annual travel distances) were found to confer risk, predicting greater captive juvenile losses and stereotypic time-budgets. This finding advances our understanding of the evolutionary basis for welfare problems in captive Carnivora, helping explain why naturally sedentary species (e.g. American mink) may breed even in intensive farm conditions, while others (e.g. polar bears, giant pandas) can struggle even in modern zoos and conservation breeding centres. Naturally itinerant lifestyles involve decision-making, and strategic shifts between locations, suggesting that supplying more novelty, cognitive challenge and/or opportunities for control will be effective ways to meet these animals' welfare needs in captivity.
Cold comfort: metabolic rate and tolerance to low temperatures predict latitudinal distribution in ants
Authors: Willot Quentin , Ørsted Michael , Malte Hans , Overgaard Johannes
Published: September 2023

Metabolic compensation has been proposed as a mean for ectotherms to cope with colder climates. For example, under the metabolic cold adaptation and the metabolic homeostasis hypotheses (MCA and MHH), it has been formulated that cold-adapted ectotherms should display both higher (MCA) and more thermally sensitive (MHH) metabolic rates (MRs) at lower temperatures. However, whether such compensation can truly be associated with distribution, and whether it interplays with cold tolerance to predict species’ climatic niches, remains largely unclear despite broad ecological implications thereof. Here, we teased apart the relationship between MRs, cold tolerance and distribution, to test the MCA/MHH among 13 European ant species. We report clear metabolic compensation effects, consistent with the MCA and MHH, where MR parameters strongly correlated with latitude and climatic factors across species’ distributions. The combination of both cold tolerance and MRs further upheld the best predictions of species' environmental temperatures and limits of northernmost distribution. To our knowledge, this is the first study showing that the association of metabolic data with cold tolerance supports better predictive models of species’ climate and distribution in social insects than models including cold tolerance alone. These results also highlight that adaptation to higher latitudes in ants involved adjustments of both cold tolerance and MRs, to allow this extremely successful group of insects to thrive under colder climates.
A General Approach to Adjusting Genetic Studies for Assortative Mating
Authors: Bilghese Marta , Manansala Regina , Jaishankar Dhruva , Jala Jonathan , Benjamin Daniel J. , Kimball Miles , Auer Paul L. , Livermore Michael A. , Turley Patrick
Published: September 2023

The effects of assortative mating (AM) on estimates from genetic studies has been receiving increasing attention in recent years. We extend existing AM theory to more general models of sorting and conclude that correct theory-based AM adjustments require knowledge of complicated, unknown historical sorting patterns. We propose a simple, general-purpose approach using polygenic indexes (PGIs). Our approach can estimate the fraction of genetic variance and genetic correlation that is driven by AM. Our approach is less effective when applied to Mendelian randomization (MR) studies for two reasons: AM can induce a form of selection bias in MR studies that remains after our adjustment; and, in the MR context, the adjustment is particularly sensitive to PGI estimation error. Using data from the UK Biobank, we find that AM inflates genetic correlation estimates between health traits and education by 14% on average. Our results suggest caution in interpreting genetic correlations or MR estimates for traits subject to AM.
Reduced social function in experimentally evolvedDictyostelium discoideumimplies selection for social conflict in nature
Authors: Larsen Tyler J. , Jahan Israt , Brock Debra A. , Strassmann Joan E. , Queller David C.
Published: September 2023

Many microbes interact with one another, but the difficulty of directly observing these interactions in nature makes interpreting their adaptive value complicated. The social amoebaDictyostelium discoideumforms aggregates wherein some cells are sacrificed for the benefit of others. Within chimeric aggregates containing multiple unrelated lineages, cheaters can gain an advantage by undercontributing, but the extent to which wildD. discoideumhas adapted to cheat is not fully clear. In this study, we experimentally evolvedD. discoideumin an environment where there were no selective pressures to cheat or resist cheating in chimeras.D. discoideumlines grown in this environment evolved reduced competitiveness within chimeric aggregates and reduced ability to migrate during the slug stage. By contrast, we did not observe a reduction in cell number, a trait for which selection was not relaxed. The observed loss of traits that our laboratory conditions had made irrelevant suggests that these traits were adaptations driven and maintained by selective pressuresD. discoideumfaces in its natural environment. Our results suggest thatD. discoideumfaces social conflict in nature, and illustrate a general approach that could be applied to searching for social or non-social adaptations in other microbes.

SIGNIFICANCE STATEMENT

Microbes interact in diverse and important ways, but the difficulty of directly observing microbes in nature can make it challenging to understand the adaptive significance of these interactions. In this study, we present an experimental evolution approach to infer the selective pressures behind an apparently social trait in the microbeDictyostelium discoideum.We take advantage of the observation that organisms ‘use it or lose it’ – when selective pressures are relaxed, adaptations that evolved in response to those pressures tend to be lost. Our work helps resolve debate over the importance of cheating inD. discoideum,and demonstrates a general approach that could be applied to the study of other microbial traits that are difficult to observe in nature.
Memorability shapes perceived time (and vice versa)
Authors: Ma Alex , Cameron Ayana , Wiener Martin
Published: September 2023

Visual stimuli are known to vary in their perceived duration. Likewise, some visual stimuli are also known to linger for longer in memory. Yet, whether or not these two features of visual processing are linked is unknown. Despite early assumptions that time is an extracted, or higher-order feature of perception, more recent work over the past two decades has demonstrated that timing may be instantiated within sensory modality circuits. A primary location for many of these studies is the visual system, where duration sensitive responses have been demonstrated. Further, visual stimulus features have been observed to shift perceived duration. These findings suggest that visual circuits mediate or construct perceived time. Here, we present across a series of experiments evidence that perceived time is affected by the image properties of scene size, clutter, and memorability. More specifically, we observe that scene size and memorability dilate time, whereas clutter contracts it. Further, the durations of more memorable images are also perceived more precisely. Conversely, the longer the perceived duration of an image, the more memorable it is. To explain these findings, we applied a recurrent convolutional neural network (rCNN) model of the ventral visual system, in which images are progressively processed over time. We find that more memorable images are processed faster, and that this increase in processing speed predicts both the lengthening and increased precision of perceived durations. These findings thus provide a new avenue in vision research towards the study of perceived image durations as means of explaining visual system responses.
Structural and Energetic Details for the Formation of cGAS-DNA Oligomers
Authors: Wang Xiaowen , Li Wenjin
Published: September 2023

Upon binding to cytosolic DNA, the cyclic GMP-AMP synthase (cGAS) is activated to catalyze the synthesis of cGAMP, which then activates downstream effectors and induces innate immune responses. The activation of cGAS relies on the formation of cGAS-DNA oligomers and liquid phase condensation, which are sensitive to the length and concentration of DNA. For a thorough understanding of such a length-and concentration-dependent activation, the details of the cGAS-DNA oligomerization are required. Here, with molecular dynamics (MD) simulations, we report the structure of the cGAS-DNA monomer (the cGAS1-DNA1complex), in which the DNA binds simultaneously to the major parts of two DNA-binding sites as observed in the cGAS-DNA dimer (the cGAS2-DNA2complex) and the active site is largely immature. Energetic analysis reveals that two cGAS1-DNA1complexes are just slightly less stable than the cGAS2-DNA2complex and the energy barrier for the formation of cGAS2-DNA2complex from two cGAS1-DNA1complexes is high, suggesting that cGAS-DNA oligomerization is unfavored thermodynamically and kinetically in low concentration of cGAS and DNA. However, the formation of cGAS4-DNA2complex from one molecule of cGAS2-DNA2complex between cGAS and long DNA and two molecules of cGAS are energetically favored without energy barrier.
A cryo-ET study of ciliary rootlet organization
Authors: van Hoorn Chris , Carter Andrew P.
Published: September 2023

Ciliary rootlets are striated bundles of filaments that connect the base of cilia to internal cellular structures. Rootlets are critical for the sensory and motile functions of cilia. However, the mechanisms underlying these functions remain unknown, in part due to a lack of structural information of rootlet organization. In this study, we obtain 3D reconstructions of membrane-associated and purified rootlets using cryo-electron tomography (cryo-ET). We show that flexible protrusions on the rootlet surface, which emanate from the cross-striations, connect to intracellular membranes. In purified rootlets, the striations were classified into amorphous (A)-bands, associated with accumulations on the rootlet surface, and discrete (D)-bands corresponding to punctate lines of density that run through the rootlet. These striations connect a flexible network of longitudinal filaments. Subtomogram averaging suggests the filaments consist of two intertwined coiled coils. The rootlet’s filamentous architecture, with frequent membrane-connecting cross-striations, lends itself well for anchoring large membranes in the cell.
Multiscale effects of perturbed translation dynamics inform antimalarial design
Authors: Anton Leonie , Cheng Wenjing , Haile Meseret T. , Cobb David W. , Zhu Xiyan , Han Leyan , Li Emerson , Nair Anjali , Lee Carolyn L. , Ke Hangjun , Zhang Guoan , Doud Emma H. , Ho Chi-Min
Published: September 2023

Malaria parasites rely heavily on rapid, high fidelity protein synthesis to infect and replicate in human erythrocytes, making translation an attractive target for new antimalarials. Here, we have determinedin situstructures ofPf80S ribosomes in thirteen conformational and compositional states from cryoFIB-milledPlasmodium falciparum-infected human erythrocytes across the stages of asexual intraerythrocytic parasite replication. We observe eight active translation intermediates, enabling us to define the native malarial translation elongation cycle, which surprisingly features a bifurcation at the decoding stage of the cycle that has not previously been described. Examination of perturbations in the distribution of ribosomes among these states in the presence of a malaria-specific translation inhibitor suggests that the inhibitor impedesPfeEF2 andPfeEF1α interactions with the ribosome. We integrated ourin situcryoET data with proteomic and ultrastructural data to arrive at a deeper understanding of malarial translation, which will inform development of new therapies.
Atrial Fibrillation Inpatient Management Patterns and Clinical Outcomes During The Conflict In Syria: An Observational Cohort Study
Authors: Antoun Ibrahim , Alkhayer Alkassem , Kotb Ahmed , Hanafi Ibrahim , Mahfoud Yaman , Barker Joseph , Mavilakandy Akash , Alkhayer Alamer , Shah Saif , Simon Peter , Somani Riyaz , Andre’ Ng G
Published: September 2023

Background

Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide. However, there is no data on AF inpatient management strategies and clinical outcomes in Syria.

Objectives

This study aims to navigate AF inpatient management and cardiovascular (CV) mortality in a tertiary cardiology centre in Latakia, Syria.

Methods

A single-centre retrospective observational cohort study was conducted at Tishreen’s University Hospital, Latakia, Syria, from June 2021 to June 2023. We included patients ≥16 years of age presenting and being treated for AF as the primary diagnosis at the emergency department. Medical records were examined for patient demographics, laboratory results, treatment plans and inpatient details. Inpatient cardiovascular mortality was the primary outcome of interest.

Results

The study included 596 patients. The median age was 58 and 61% were males. Only 121 patients (20.3%) were known to have AF. Rhythm control strategy was persuaded in 39% of patients, with Amiodarone being the only agent utilised while the rest adopted a rate control approach. CV Mortality occurred in 28 patients (4.7%). The presence of smoking (aOR: 1.6, 95% CI: 1.3 to 2.1, P=0.04), thyroid disease (aOR= 9.7, 95% CI= 1.2 to 91.6, P<0.001), COPD (aOR: 82, 95% CI: 12.7 to 711, P<0.001) and valvular heart disease (VHD) (aOR= 9.1, 95% CI: 1.7 to 55.1, P<0.001) were independent risk factors of cardiovascular inpatient mortality.

Conclusion

Current smoking, thyroid disease, COPD and VHD were independent risk factors of inpatient cardiovascular mortality with AF in Syria. Elective rhythm control was challenging due to limited resources.
Single-Molecule Tracking Reveals Dynamic Regulation of Ribosomal Scanning
Authors: Hong Hea Jin , Zhang Antonia L. , Conn Adam B. , Blaha Gregor , O’Leary Seán E.
Published: September 2023

To initiate protein synthesis, the eukaryotic ribosomal pre-initiation complex must survey a messenger RNA leader sequence to identify the correct start codon.1This pre-initiation complex motion through the leader, termed ‘scanning’, is coordinated by an intricate and highly-dynamic assemblage of translation factors, mRNA, initiator tRNA, and the small ribosomal subunit.2,3,4Fundamental aspects of scanning dynamics remain poorly understood: estimates of its rate vary widely, and mechanisms that establish and regulate the motion remain largely unknown. Here we show, at the single-molecule level, that theSaccharomyces cerevisiaepre-initiation complex scans a diverse set of mRNA leaders at a rate of 10 – 20 nt s−1. Our data quantitatively support a scanning mechanism in which the mRNA leader is inspected base by base, essentially unidirectionally, and with modest sensitivity to mRNA structure. Unexpectedly, scanning bypasses canonical start sites where the initiator tRNA is present but GTP hydrolysis in the pre-initiation complex is impaired. Conversely, binding of theS. cerevisiaepoly(A)-binding protein Pab1p to its own mRNA leader hinders scanning in a concentration-dependent manner. At saturating, physiological concentrations, Pab1p prolongs scanning by more than four-fold, evoking an autoregulation mechanism for translation initiation. Our data provide a real-time mechanistic framework for scanning regulation and energetics.
Emerging Links Between COVID-19 and Cardiovascular & Cerebrovascular Thromboembolic Events: A Systematic Review
Authors: Agarwal Abhimanyu , Panjiyar Binay K , Manishbhai Patel Dhwani , Ghotra Monica , Husain Mahato Gulam Husain Nabi , Brijeshkumar Upadhyay Ronak
Published: September 2023

COVID-19, caused by the SARS-CoV-2 virus, initially identified as a respiratory illness, has increasingly been linked to a broader range of organ complications. This systematic review explores the impact of COVID-19 on cardiovascular and cerebrovascular health, focusing on thromboembolic events in post-COVID patients. A comprehensive literature search was conducted in PubMed and Google Scholar databases up to July 2023, utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies meeting eligibility criteria were analyzed for outcomes and associations between COVID-19 and cardiovascular and cerebrovascular events. The review includes 6 studies involving over 12 million patients, demonstrating a strong connection between COVID-19 and elevated risks of cardiovascular and cerebrovascular thromboembolic events. The risk of these events is evident in conditions such as ischemic heart disease, stroke, and cardiac arrhythmias. The burden of these events beyond the acute phase of the disease is concerning, warranting further exploration of long-term implications. Variability in event rates among different cohorts and healthcare settings underscores the need for understanding underlying factors influencing these differences. Potential mechanisms behind these events include endothelial dysfunction, systemic inflammation, and viral invasion. Implications for public health policies, clinical guidelines, and future research directions are discussed. This review serves as a valuable resource for healthcare providers, policymakers, and researchers to enhance patient care, outcomes, and preparedness for future waves of COVID-19 infections. However, there remain unexplored aspects of the COVID-19 and thromboembolic events relationship, urging further investigations into mechanistic insights and potential therapeutic interventions.
Atrial arrhythmogenesis in ex vivo aged mouse hearts with hypokalemia and right atrial stretch
Authors: Cayton Jessica , Nourian Zahra , Lambert Michelle , Liu Zhenguo , Domeier Timothy L.
Published: September 2023

Introduction

Atrial Fibrillation (AF) and atrial flutter (AFL) are the two most common cardiac arrhythmias in the United States. While advanced age has been correlated to AF/AFL, the lack of an appropriate animal model has hindered progress on better understanding the pathophysiology of atrial arrhythmogenesis. Both hypokalemic conditions and hemodynamic stretch have been associated with atrial tachyarrhythmias in patient populations. The purpose of this study was to examine the incidence of atrial tachyarrhythmias in an ex vivo aging C57BL/6 mouse model following hypokalemia and stretch challenges.

Methods

Hearts were isolated with combined cannulation of the aorta and superior vena cava in a modified right-sided working heart perfusion technique. Isolated hearts of Aged (26-29 month) male (n=14) and female (n=14) mice were subjected to normokalemic and hypokalemic conditions ± atrial preload elevation to 12 cmH20 to induce atrial stretch. Heart rate, right ventricular (RV) pressure development, and incidence of atrial tachyarrhythmias were monitored using a pressure catheter and intracardiac electrocardiogram.

Results

In response to hypokalemia, there were no changes in mean heart rate, RV pressure development, or RV Rate-Pressure Product (Rate x RV peak pressure). Atrial tachyarrhythmias were not observed under baseline conditions, and only 1 of 8 hearts exhibited atrial tachycardia following the hypokalemia challenge. In response to atrial preload elevation, there was an increase in heart rate (P=0.0006 versus baseline) with no change in RV pressure development. RV Rate-Pressure Product was significantly elevated (P=0.013 versus baseline) with atrial preload due to the increase in heart rate.

Atrial tachyarrhythmias were not observed under both baseline conditions and following atrial preload elevation. In response to the combined hypokalemia and preload challenges, there was an increase in heart rate (P=0.008 versus baseline) with no change in RV pressure development or RV Rate Pressure product. Atrial tachyarrhythmias were not observed under baseline conditions, yet after the combined challenges 50% of aged hearts exhibited atrial tachycardia or AF/AFL. During bouts of AF/AFL, the AF/AFL led to a variable ventricular response and concomitant contractile dysfunction in the form of variable RV pressure development.

Conclusion

Ex vivo aged mouse hearts exhibit atrial tachyarrhythmias in response to combined hypokalemia and right atrial stretch conditions. The aged C57BL/6 mouse model is therefore useful for pre-clinical studies of atrial arrhythmogenesis.
A pangenomic atlas reveals that eco-evolutionary dynamics shape plant pathogen type VI secretion systems
Authors: Aoun Nathalie , Georgoulis Stratton J. , Avalos Jason K. , Grulla Kimberly J. , Miqueo Kasey , Tom Cloe , Lowe-Power Tiffany M.
Published: September 2023

Soil-borneRalstonia solanacearumspecies complex (RSSC) bacteria disrupt rhizosphere and endophytic microbial communities as they invade roots and fatally wilt plants. RSSC pathogens secrete antimicrobial toxins using a type VI secretion system (T6SS). To investigate how evolution and ecology have shaped pathogen T6SS biology, we analyzed the T6SS gene content and architecture across the RSSC pangenome and their evolutionarily relatives. Our analysis reveals that two ecologically similar Burkholderiaceae taxa, xylem pathogenic RSSC bacteria andAcidovorax, have convergently evolved to wield large arsenals of T6SS toxins. To understand the mechanisms underlying genomic enrichment of T6SS toxins, we compiled an atlas of 1,069 auxiliary (“aux”) T6SS toxin clusters across 99 high-quality RSSC genomes. We classified 25 types ofauxclusters with toxins that predominantly target lipids, nucleic acids, or unknown cellular substrates. Theauxclusters were in diverse genetic neighborhoods and had complex phylogenetic distributions, suggesting frequent horizontal gene flow. Phages and other mobile genetic elements account for most of theauxcluster acquisition on the chromosome but very little on the megaplasmid. Nevertheless, RSSC genomes were more enriched inauxclusters on the megaplasmid. Secondary replicons like megaplasmids often evolve more rapidly than the more evolutionarily stable chromosome. Although the single ancestral T6SS was broadly conserved in the RSSC, the T6SS was convergently lost in atypical lineages with vectored transmission. Overall, our data suggest dynamic interplay between the lifestyle of soil-transmitted RSSC lineages and the evolution of T6SSs with robust arsenals of toxins. This pangenomic atlas poises the RSSC as an emerging, tractable model to understand the role of the T6SS in shaping pathogen populations.
Magnitude and Kinetics of a set of Neuroanatomic Volume and Thickness together with White Matter Hyperintensity is definitive of Cognitive Status and Brain Age
Authors: Yadav Neha , Gupta Niraj Kumar , Thakar Darshit , Tiwari Vivek
Published: September 2023

In an aging population, a subset of individuals at a given age group have low white matter hyperintensity (WMH) while another subset has intermediate to high WMH load. WMH load quantification together with comprehensive neuroanatomic volumetry needs to be examined together for establishing a unique precise and optimal number of brain features as a noninvasive indicator of ‘Brain Age’ and cognitive status. Here, a comprehensive neuroanatomic volumetry together with WMH quantification using longitudinal MRI and cognitive measurements from two aging cohorts have been performed together with machine learning modeling of the quantitative changes with aging to establish Optimal unique brain events discriminative of cognitive status and estimative of Brain Age. A set of Three optimal brain-associated quantities; wherein two are neuroanatomic features Total brain volume; CSF volume, and the third is the extent of microvascular pathology WMH load, provide highly precise discrimination of cognitive status as cognitively normal (CN), impaired (CI) and AD (CI-AD). While medial cortical thinning of Parahippocampal gyrus is an ‘early age event’ discriminative between CI and CI-AD but loss of hippocampus, gray matter and white matter volume lacks sensitivity to discriminate between CI and CI-AD. The Brain Age estimation using the neuroanatomic volumetry and periventricular and deep WMH load indicates that elevated WMH load in the brain led to an increased Brain Age gap than the brain with low WMH at a given chronological age. Increased Brain Age gap with elevated WMH load at the early age groups is suggestive of profound vascular insult arising from WMH to the brain structure and function.
Funding startups using contingent option of value appreciation: theory and formula
Authors: Wang Shaun Shuxun
Published: September 2023

Purpose

This paper provides a structural model to value startup companies and determine the optimal level of research and development (R&D) spending by these companies.

Design/methodology/approach

This paper describes a new variant of float-the-money options, which can act as a financial instrument for financing R&D expenses for a specific time horizon or development stage, allowing the investor to share in the startup's value appreciation over that duration. Another innovation of this paper is that it develops a structural model for evaluating optimal level of R&D spending over a given time horizon. The paper deploys the Gompertz-Cox model for the R&D project outcomes, which facilitates investigation of how increased level of R&D input can enhance the company's value growth.

Findings

The author first introduces a time-varying drift term into standard Black-Scholes model to account for the varying growth rates of the startup at different stages, and the author interprets venture capital's investment in the startup as a “float-the-money” option. The author then incorporates the probabilities of startup failures at multiple stages into their financial valuation. The author gets a closed-form pricing formula for the contingent option of value appreciation. Finally, the author utilizes Cox proportional hazards model to analyze the optimal level of R&D input that maximizes the return on investment.

Research limitations/implications

The integrated contingent claims model links the change in the financial valuation of startups with the incremental R&D spending. The Gompertz-Cox contingency model for R&D success rate is used to quantify the optimal level of R&D input. This model assumption may be simplistic, but nevertheless illustrative.

Practical implications

Once supplemented with actual transaction data, the model can serve as a reference benchmark valuation of new project deals and previously invested projects seeking exit.

Social implications

The integrated structural model can potentially have much wider applications beyond valuation of startup companies. For instance, in valuing a company's risk management, the level of R&D spending in the model can be replaced by the company's budget for risk management. As another promising application, in evaluating a country's economic growth rate in the face of rising climate risks, the level of R&D spending in this paper can be replaced by a country's investment in addressing climate risks.

Originality/value

This paper is the first to develop an integrated valuation model for startups by combining the real-world R&D project contingencies with risk-neutral valuation of the potential payoffs.
The interplay of entrepreneurial personality and startup innovativeness – the mediation effect of technology adoption
Authors: Becker Felix Simon Rudolf , Escoz Barragan Kevin , Huge sive Huwe Daria , Ernst Beatrice Shenara , Strina Giuseppe
Published: September 2023

Purpose

In the ever-evolving digital landscape, this study aims to explore which specific personality traits contribute to the innovativeness of startups, with a particular emphasis on understanding how technology adoption mediates this relationship. By doing so, the authors strive to unveil the nuanced dynamics of personality, technology adoption and startup innovativeness in the digital era.

Design/methodology/approach

The authors conduct a quantitative empirical analysis using a sample of 1,314 German startups. This study utilizes a mediation analysis to examine the effects of personality traits on the innovativeness of startups, taking technology adoption as a mediator into account.

Findings

The empirical results show certain personality traits have direct effects on innovativeness. Also, the results show that technology adoption is a driver of startup innovativeness. In addition, these traits are (partially) mediated by technology adoption.

Research limitations/implications

The results shed new light on the interplay of entrepreneurs' personality and technology adoption in relation to startup innovativeness and therefore underline the importance of technology in this triangular relationship. The authors employ secondary data from startups in Germany, which complicates generalization of the results to other geographical and cultural contexts.

Originality/value

This study contributes to the scientific debate on the role of personality traits in entrepreneurship by providing empirical evidence on the mediating effect of technology adoption in the relationship between personality traits and startup innovativeness. The findings offer valuable insights for researchers, entrepreneurs and policymakers interested in understanding and promoting innovativeness in the context of startups.
Mobilising big data analytics capabilities to improve performance of tourism supply chains: the moderating role of dynamic capabilities
Authors: Gupta Yuvika , Khan Farheen Mujeeb , Kumar Anil , Luthra Sunil , Queiroz Maciel M.
Published: September 2023

Purpose

With the emergence of big data analytics and the importance of analytics-driven decisions, the travel industry is swiftly jumping on and adopting the bandwagon. However, research in this domain is limited. Accordingly, the present research seeks to understand how big data analytics capabilities (BDAC) add value to tourism supply chains (TSCs) and can dynamic capabilities (DC) improve the triple bottom line.

Design/methodology/approach

Data from 218 valid responses were collected from different Indian tourism industry units. Confirmatory factor analysis (CFA) was applied to confirm the constructs, followed by partial least squares structural equation modelling (PLS-SEM) to check the mediating effect of DC on TSCs performance.

Findings

The findings show that BDAC significantly influence the performance of TSCs and that DC plays a critical role in strengthening the impact of BDAC on TSCs' economic performance. These results corroborate that DC plays a key moderating role.

Research limitations/implications

This study contributes significantly to the tourism sector in India, where tourism is a key contributor to the country's gross domestic product. Theoretically, this study contributes to the resource-based view (RBV) and practically encourages professionals in the tourism sector to promote the use of BDAC to enhance the performance of TSCs.

Originality/value

The originality of the study is that it has tried to comprehend the moderating role of dynamic capabilities which impact BDAC to improve TSC performance.
Assessing the mediating role and multiple group analysis in physicians’ habit persistence toward prescribing behavior using SmartPLS software
Authors: Murshid Mohsen Ali , Mohaidin Zurina , Zayed Mohammad , Al-Sakkaf Mohammed Alawi , Al-Hakimi Mohammed A.
Published: September 2023

Purpose

Although there is evidence that the efforts of pharmaceutical marketing exert a positive and significant influence on physician prescription decisions, the specific mechanisms by which this impact occurs remain uncertain. To address this issue, this study aims to investigate whether the physician’s habit persistence may explain the relationship between marketing efforts such as brand attributes and drug promotion and prescribing behavior. This study also explores whether there was any significant difference between specialists and general practitioners (GPs) regarding the effect of brand attributes and drug promotion on physician’s habit persistence, which influences prescribing behavior.

Design/methodology/approach

A survey instrument was administered to physicians, encompassing specialists in a particular field and GPs who provide primary care services. A nonparametric partial least squares multigroup analysis was used to analyze 393 valid responses using partial least squares-structural equation modeling.

Findings

The results indicate that the decision to prescribe the drug may be affected by the physician’s habit persistence in the presence of vital brand attributes and drug promotion. The relationship between physician’s habit persistence and prescribing behavior is significant in GPs and specialist groups. The findings also reveal that brand attributes are the most influential and significant determinant of physician’s habit persistence in the GPs group. In addition, physician specialists are more aware of the influence of drug promotion initiatives than GPs. Furthermore, this study discovered that the relationship between drug promotion and physician’s habit persistence indicates a significant difference between specialists and GPs.

Originality/value

Although several marketing scholars discuss the factors influencing prescribing behavior, a few studies have shown the role of brand attributes and drug promotion and their effect on physician’s habit persistence. This study will specifically contribute by examining the mediating role of physician’s habit persistence between marketing efforts and prescribing behavior. In addition, so far, no studies have effectively made a comparative analysis across physicians regarding the effect of marketing efforts on physician’s habit persistence and prescribing behavior.
Cloud computing adoption decision-making process: a sensemaking analysis
Authors: Polyviou Ariana , Pouloudi Nancy , Venters Will
Published: September 2023

Purpose

The authors study how cloud adoption decision making unfolds in organizations and present the dynamic process leading to a decision to adopt or reject cloud computing. The authors thus complement earlier literature on factors that influence cloud adoption.

Design/methodology/approach

The authors adopt an interpretive epistemology to understand the process of cloud adoption decision making. Following an empirical investigation drawing on interviews with senior managers who led the cloud adoption decision making in organizations from across Europe. The authors outline a framework that shows how cloud adoptions follow multiple cycles in three broad phases.

Findings

The study findings demonstrate that cloud adoption decision making is a recursive process of learning about cloud through three broad phases: building perception about cloud possibilities, contextualizing cloud possibilities in terms of current computing resources and exposing the cloud proposition to others involved in making the decision. Building on these findings, the authors construct a framework of this process which can inform practitioners in making decisions on cloud adoption.

Originality/value

This work contributes to authors understanding of how cloud adoption decisions unfold and provides a framework for cloud adoption decisions that has theoretical and practical value. The study further demonstrates the role of the decision-leader, typically the CIO, in this process and identifies how other internal and external stakeholders are involved. It sheds light on the relevance of the phases of the cloud adoption decision-making process to different cloud adoption factors identified in the extant literature.
Environmental factors, ambidexterity and performance in SMEs: does bricolage matter?
Authors: Lee Juyeon , Park Taekyung
Published: September 2023

Purpose

Growing attention has been paid to bricolage as a strategic means to overcome resource constraints in small and medium-sized enterprises (SMEs). In the industrial market, a bricolage strategy and ambidextrous action may help firms to remain competitive by responding quickly to the business-to-business marketing. Despite its paramount importance, questions as to how bricolage is strengthened and how bricolage improves innovation ambidexterity have remained unanswered. This study aims to develop an integrated model for the relationships among environmental turbulence, learning orientation, ambidexterity and performance, with a particular focus on the mediation of bricolage.

Design/methodology/approach

Building on the literature review regarding the key constructs, hypotheses were developed. Data were collected using questionnaires from 229 SMEs in South Korea. To test hypothesis, structural equation modeling and Monte Carlo method for assessing mediation were performed.

Findings

Results reveal that environmental turbulence and learning orientation are positively associated with bricolage, which sequentially affects ambidextrous action as a driver of performance. The findings also indicate that bricolage significantly mediates the relationship between its antecedents and ambidexterity.

Originality/value

This research contributes to advancing our understanding of the role of a bricolage strategy for innovation ambidexterity and performance in SMEs. This study is the first to examine the mediation of bricolage between environmental factors and ambidexterity for improved performance.