bluuebunny/crossref_metadata_2025 huggingface dataset:
Long‐term warming increased carbon sequestration capacity in a humid subtropical forest
Authors: Liu Xujun , Lie Zhiyang , Reich Peter B. , Zhou Guoyi , Yan Junhua , Huang Wenjuan , Wang Yingping , Peñuelas Josep , Tissue David T. , Zhao Mengdi , Wu Ting , Wu Donghai , Xu Wenfang , Li Yuelin , Tang Xuli , Zhou Shuyidan , Meng Ze , Liu Shizhong , Chu Guowei , Zhang Deqiang , Zhang Qianmei , He Xinhua , Liu Juxiu
Published: December 2023

Tropical and subtropical forests play a crucial role in global carbon (C) pools, and their responses to warming can significantly impact C‐climate feedback and predictions of future global warming. Despite earth system models projecting reductions in land C storage with warming, the magnitude of this response varies greatly between models, particularly in tropical and subtropical regions. Here, we conducted a field ecosystem‐level warming experiment in a subtropical forest in southern China, by translocating mesocosms (ecosystem composed of soils and plants) across 600 m elevation gradients with temperature gradients of 2.1°C (moderate warming), to explore the response of ecosystem C dynamics of the subtropical forest to continuous 6‐year warming. Compared with the control, the ecosystem C stock decreased by 3.8% under the first year of 2.1°C warming; but increased by 13.4% by the sixth year of 2.1°C warming. The increased ecosystem C stock by the sixth year of warming was mainly attributed to a combination of sustained increased plant C stock due to the maintenance of a high plant growth rate and unchanged soil C stock. The unchanged soil C stock was driven by compensating and offsetting thermal adaptation of soil microorganisms (unresponsive soil respiration and enzyme activity, and more stable microbial community), increased plant C input, and inhibitory C loss (decreased C leaching and inhibited temperature sensitivity of soil respiration) from soil drying. These results suggest that the humid subtropical forest C pool would not necessarily diminish consistently under future long‐term warming. We highlight that differential and asynchronous responses of plant and soil C processes over relatively long‐term periods should be considered when predicting the effects of climate warming on ecosystem C dynamics of subtropical forests.
Evaluating the prescribing and monitoring of medications associated with QTc‐prolongation in the ambulatory care setting
Authors: Lowe Rachel N. , Wright Garth , Olivas Lucas , Teel Candance , Suresh Krithika , Macke Laura B. , Sieja Amber , Rosenberg Michael A. , Trinkley Katy E.
Published: December 2023

Rationale

Little is known about the prescribing of medications with potential to cause QTc‐prolongation in the ambulatory care settings. Understanding real‐world prescribing of QTc‐prolonging medications and actions taken to mitigate this risk will help guide strategies to optimize safety and appropriate prescribing among ambulatory patients.

Objective

To evaluate the frequency of clinician action taken to monitor and mitigate modifiable risk factors for QTc‐prolongation when indicated.

Methods

This retrospective, cross‐sectional study evaluated clinician action at the time of prescribing prespecified medications with potential to prolong QTc in adult patients in primary care. The index date was defined as the date the medication was ordered. Electronic health record (EHR) data were evaluated to assess patient, clinician and visit characteristics. Clinician action was determined if baseline or follow‐up monitoring was ordered or if action was taken to mitigate modifiable risk factors (laboratory abnormalities or electrocardiogram [ECG] monitoring) within 48 h of prescribing a medication with QTc‐prolonging risk. Descriptive statistics were used to describe current practice.

Results

A total of 399 prescriptions were prescribed to 386 patients, with a mean age of 51 ± 18 years, during March 2021 from a single‐centre, multisite health system. Of these, 17 (4%) patients had a known history of QTc‐prolongation, 170 (44%) did not have a documented history of QTc‐prolongation and 199 (52%) had an unknown history (no ECG documented). Thirty‐nine patients (10%) had at least one laboratory‐related risk factor at the time of prescribing, specifically hypokalemia (16 patients), hypomagnesemia (8 patients) or hypocalcemia (19 patients). Of these 39 patients with laboratory risk factors, only 6 patients (15%) had their risk acknowledged or addressed by a clinician. Additionally, eight patients' most recent QTc was ≥500 ms and none had an ECG checked at the time the prescription was ordered.

Conclusion

Despite national recommendations, medication monitoring and risk mitigation is infrequent when prescribing QTc‐prolonging medications in the ambulatory care setting. These findings call for additional research to better understand this gap, including reasons for the gap and consequences on patient outcomes.
The alphabet and idiosyncratic volatility
Authors: Bergers Okke , Blomkvist Magnus
Published: December 2023

We find that stocks with names earlier in an alphabetic ordering exhibit greater idiosyncratic volatility. Stocks whose names are in the first 5% of an alphabetic ordering have 4.5% higher idiosyncratic volatility relative to other stocks. To address potential concerns about early‐alphabet firms being different, we study name changes. Idiosyncratic volatility is 7% higher when a name change causes a stock to move into the first 5%. We attribute these results to noise traders being more active in early‐alphabet stocks because of heuristic‐based investing. In support of this explanation, we find that the effect is strongest during periods of high investor sentiment and among stocks with high turnover. Our results provide evidence that noise traders contribute to the idiosyncratic volatility of stocks.
The process through which nurses providing care to COVID‐19 patients recognize professional growth: A Trajectory Equifinality Model
Authors: Inoue Maho , Takemura Yukie , Kitamura Aya , Isobe Tamaki
Published: December 2023

Aim

This study investigated the ways in which nurses caring for COVID‐19 patients during the pandemic's early stages recognized professional growth through their experiences and continued working for several years, as well as the key experiences for identifying professional growth, external factors, and career intentions.

Methods

We used a qualitative research method called the Trajectory Equifinality Model (TEM). The participants were nine nurses caring for COVID‐19 patients during the pandemic's early stages and had already recognized professional growth through a series of experiences. We constructed a TEM diagram based on two interviews per participant (in February–March, and July–August 2022).

Results

The process by which the participants recognized professional growth through a series of experiences was divided into Phases 1–4. The participants experienced adversity in Phases 1 and 3, and the following professional growth in Phases 2 and 4: gaining confidence as a nurse performing tasks of great social significance by acquiring the ability to fulfill my roles and realizing I could use the skills I had acquired by providing nursing care to COVID‐19 patients in other situations, respectively. The key experiences for identifying professional growth as well as the inhibiting and facilitating factors of the process differed depending on the phase. The participants' career intention was wanting to continue to be involved in nursing by utilizing the skills and experience I have accumulated.

Conclusion

Managers and directors of nursing should provide appropriate support in each phase to help nurses recognize their professional growth during emerging epidemics.
Mothers' and birthing parents' experiences with 1‐day cognitive behavioural therapy‐based workshops for postpartum depression: A descriptive qualitative study
Authors: Varambally Meghna , Layton Haley , Jack Susan M. , Van Lieshout Ryan J.
Published: December 2023

Accessible Summary

What Is Known about the Subject?

One in five mothers and birthing parents are affected by postpartum depression (PPD), yet only a small proportion of those with PPD receive treatment.

Given cost and accessibility barriers to treatment, brief therapies (e.g. 1 day) could help address PPD on a large scale, though understanding participants' unique experiences with this novel treatment will help guide its refinement and use.

What this Paper Adds to Existing Knowledge?

This paper describes the experiences, perspectives and satisfaction of participants who attended a 1‐day workshop for PPD.

Participants appreciate being taught practical techniques and the receipt of social support from facilitators and other attendees in the group setting, while some recommended further ‘booster sessions’ to enhance effectiveness.

What Are the Implications for Practice?

One‐day CBT‐based workshops may be an effective, low‐intensity treatment option that provides helpful skills and builds social networks for individuals with PPD.

Additional post‐workshop booster sessions may enhance participant satisfaction with this new treatment by providing a reinforcement of their learning and an opportunity to re‐connect with other birthing parents.

Introduction

Postpartum depression (PPD) affects up to one in five mothers and birthing parents. Understanding their perceptions of therapeutic interventions is key to their effectiveness and scalability.

Aim

The aim of the study was to understand participants' experiences attending an in‐person or online 1‐day cognitive behavioural therapy (CBT)‐based workshop for PPD and compare their experiences participating in either modality.

Method

This descriptive qualitative study was embedded in two separate randomized controlled trials evaluating the effectiveness of 1‐day CBT‐based workshops for PPD delivered in‐person or online. Responses were provided by 94 in‐person and 95 online participants about their experiences. Content analysis was used to code and categorize the data.

Results

Participants appreciated learning skills to improve PPD symptoms and joining a community of individuals with shared experiences. Integrating practical coping techniques after the workshop was reported to be most useful, though some wanted additional post‐workshop support. Online participants identified additional barriers to workshop engagement.

Discussion

Participants who attended either workshop found them to be valuable and effective. Participants valued psychoeducation, social connections and applying practical CBT techniques.

Implications for Practice

One‐day CBT‐based workshops may be an accessible treatment option for individuals with PPD, providing new skills and social support, though some prefer to receive additional post‐workshop support.
Population genomic structure of a widespread, urban‐dwelling mammal: The eastern grey squirrel (Sciurus carolinensis)
Authors: Fusco Nicole A. , Cosentino Bradley J. , Gibbs James P. , Allen Maximilian L. , Blumenfeld Alexander J. , Boettner George H. , Carlen Elizabeth J. , Collins Merri , Dennison Catherine , DiGiacopo Devin , Drapeau Picard André‐Philippe , Edmonson Jonathan , Fisher‐Reid M. Caitlin , Fyffe Rebecca , Gallo Travis , Grant Alannah , Harbold William , Heard Stephen B. , Lafferty Diana J. R. , Lehtinen Richard M. , Marino Shealyn , McDonald John E. , Mortelliti Alessio , Murray Maureen , Newman Amy , Oswald Krista N. , Ott‐Conn Caitlin , Richardson Jonathan L. , Rimbach Rebecca , Salaman Paul , Steele Michael , Stothart Mason R. , Urban Mark C. , Vandegrift Kurt , Vanek John P. , Vanderluit Sean N. , Vezina Lucie , Caccone Adalgisa
Published: December 2023

Urbanization is a persistent and widespread driver of global environmental change, potentially shaping evolutionary processes due to genetic drift and reduced gene flow in cities induced by habitat fragmentation and small population sizes. We tested this prediction for the eastern grey squirrel (Sciurus carolinensis), a common and conspicuous forest‐dwelling rodent, by obtaining 44K SNPs using reduced representation sequencing (ddRAD) for 403 individuals sampled across the species' native range in eastern North America. We observed moderate levels of genetic diversity, low levels of inbreeding, and only a modest signal of isolation‐by‐distance. Clustering and migration analyses show that estimated levels of migration and genetic connectivity were higher than expected across cities and forested areas, specifically within the eastern portion of the species' range dominated by urbanization, and genetic connectivity was less than expected within the western range where the landscape is fragmented by agriculture. Landscape genetic methods revealed greater gene flow among individual squirrels in forested regions, which likely provide abundant food and shelter for squirrels. Although gene flow appears to be higher in areas with more tree cover, only slight discontinuities in gene flow suggest eastern grey squirrels have maintained connected populations across urban areas in all but the most heavily fragmented agricultural landscapes. Our results suggest urbanization shapes biological evolution in wildlife species depending strongly on the composition and habitability of the landscape matrix surrounding urban areas.
Forward‐in‐time simulation of chromosomal rearrangements: The invisible backbone that sustains long‐term adaptation
Authors: Banse Paul , Luiselli Juliette , Parsons David P. , Grohens Théotime , Foley Marco , Trujillo Leonardo , Rouzaud‐Cornabas Jonathan , Knibbe Carole , Beslon Guillaume
Published: December 2023

While chromosomal rearrangements are ubiquitous in all domains of life, very little is known about their evolutionary significance, mostly because, apart from a few specifically studied and well‐documented mechanisms (interaction with recombination, gene duplication, etc.), very few models take them into account. As a consequence, we lack a general theory to account for their direct and indirect contributions to evolution. Here, we propose Aevol, a forward‐in‐time simulation platform specifically dedicated to unravelling the evolutionary significance of chromosomal rearrangements (CR) compared to local mutations (LM). Using the platform, we evolve populations of organisms in four conditions characterized by an increasing diversity of mutational operators—from substitutions alone to a mix of substitutions, InDels and CR—but with a constant global mutational rate. Despite being almost invisible in the phylogeny owing to the scarcity of their fixation in the lineages, we show that CR make a decisive contribution to the evolutionary dynamics by comparing the outcome in these four conditions. As expected, chromosomal rearrangements allow fast expansion of the gene repertoire through gene duplication, but they also reduce the effect of diminishing‐returns epistasis, hence sustaining adaptation on the long‐run. At last, we show that chromosomal rearrangements tightly regulate the size of the genome through indirect selection for reproductive robustness. Overall, these results confirm the need to improve our theoretical understanding of the contribution of chromosomal rearrangements to evolution and show that dedicated platforms like Aevol can efficiently contribute to this agenda.
Developmental models shed light on the earliest dental tissues, using Astraspis as an example
Authors: Houée Guillaume , Bardin Jérémie , Germain Damien , Janvier Philippe , Goudemand Nicolas
Published: December 2023

Fossils of extinct jawless vertebrates are pivotal to deciphering the evolutionary paths that led to the various forms of the vertebrate skeleton. For example, Pteraspidomorphs (stem‐gnathostomes), such as the Ordovician Astraspis, display some of the oldest remains of bony and ‘dental’ (dentine and enameloid) tissues. However, the identification of the very nature of these early mineralized tissues has been hampered by a lack of unambiguous diagnostic characters. As development is key to identifying the derivation of these tissues, we developed an integrative and generic histogenetic model, testing several ontogenetic scenarios. We illustrate our approach on the basis of the well‐preserved Astraspis samples and show how this can be used to infer key developmental features from extinct species. This study suggests that in the odontodes of Astraspis: (1) the initial curvature of the epithelium was close to the shape of the final external surface; (2) the mesenchymal cells differentiate synchronously in the whole inner periphery; and (3) the capping tissue was produced by both mesenchymal and epithelial cells (enameloid rather than enamel). Astraspis specimens also provide evidence of a dual growth periodicity, possibly homologous to Andresen and von Ebner growth lines observed in amniotes, suggesting this type of dual periodicity may be shared by most vertebrates. We estimated that an Astraspis odontode grew up in around 60–70 days at a rate of 0.5–5 μm/day. The new developmental approach proposed in this study could be a robust framework for critically evaluating the tissues of extinct taxa in the future.
Current pediatric pain practice in Nigeria, South Africa, Uganda, and Zambia: A prospective survey of anesthetists
Authors: Bhettay Anisa , Gray Rebecca , Desalu Ibironke , Parker Romy , Maswime Salome
Published: December 2023

Background

Children in hospital experience significant pain, either inherent with their pathology, or caused by diagnostic/therapeutic procedures. Little is known about pediatric pain practices in sub‐Saharan Africa. This survey aimed to gain insight into current pain management practices among specialist physician anesthetists in four sub‐Saharan African countries.

Methods

A survey was sent to 365 specialist physician anesthetists in Nigeria, South Africa, Uganda and Zambia. Content analysis included descriptive information about the respondents and their work environment. Thematic analysis considered resources available for pediatric pain management, personal and institutional pain practices.

Results

One hundred and sixty‐six responses were received (response rate 45.5%), with data from 141 analyzed; Nigeria (27), South Africa (52), Uganda (41) and Zambia (21). Most respondents (71.83%) worked at tertiary/national referral hospitals. The majority of respondents (130/141, 91.55%) had received teaching in pediatric pain management. Good availability was reported for simple analgesia, opioids, ketamine, and local anesthetics. Just over half always/often had access to nurses trained in pediatric care, and infusion pumps for continuous drug delivery. Catheters for regional anesthesia techniques and for patient‐controlled analgesia were largely unavailable. Two thirds (94/141, 66.67%) did not have an institutional pediatric pain management guideline, but good pharmacological pain management practices were reported, in line with World Health Organization recommendations. Eighty‐eight respondents (62.41%) indicated that they felt appropriate pain control in children was always/often achieved in their setting.

Conclusion

This survey provides insight into pediatric pain practices in these four countries. Good availability of a variety of analgesics, positive pain prescription practices, and utilization of some non‐pharmacological pain management strategies are encouraging, and suggest that achieving good pain control despite limited resources is attainable. Areas for improvement include the development of institutional guidelines, routine utilization of pain assessment tools, and access to regional anesthesia and other advanced pain management techniques.
Variables associated with nonresponders to high‐frequency (10 kHz) spinal cord stimulation
Authors: Tieppo Francio Vinicius , Alm John , Leavitt Logan , Mok Daniel , Yoon B. Victor , Nazir Niaman , Lam Christopher , Latif Usman , Sowder Timothy , Braun Edward , Sack Andrew , Khan Talal , Sayed Dawood
Published: December 2023

Introduction

The use of spinal cord stimulation (SCS) therapy to treat chronic pain continues to rise. Optimal patient selection remains one of the most important factors for SCS success. However, despite increased utilization and the existence of general indications, predicting which patients will benefit from neuromodulation remains one of the main challenges for this therapy. Therefore, this study aims to identify the variables that may correlate with nonresponders to high‐frequency (10 kHz) SCS to distinguish the subset of patients less likely to benefit from this intervention.

Materials and Methods

This was a retrospective single‐center observational study of patients who underwent 10 kHz SCS implant. Patients were divided into nonresponders and responders groups. Demographic data and clinical outcomes were collected at baseline and statistical analysis was performed for all continuous and categorical variables between the two groups to calculate statistically significant differences.

Results

The study population comprised of 237 patients, of which 67.51% were responders and 32.49% were nonresponders. There was a statistically significant difference of high levels of kinesiophobia, high self‐perceived disability, greater pain intensity, and clinically relevant pain catastrophizing at baseline in the nonresponders compared to the responders. A few variables deemed potentially relevant, such as age, gender, history of spinal surgery, diabetes, alcohol use, tobacco use, psychiatric illness, and opioid utilization at baseline were not statistically significant.

Conclusion

Our study is the first in the neuromodulation literature to raise awareness to the association of high levels of kinesiophobia preoperatively in nonresponders to 10 kHz SCS therapy. We also found statistically significant differences with greater pain intensity, higher self‐perceived disability, and clinically relevant pain catastrophizing at baseline in the nonresponders relative to responders. It may be appropriate to screen for these factors preoperatively to identify patients who are less likely to respond to SCS. If these modifiable risk factors are present, it might be prudent to consider a pre‐rehabilitation program with pain neuroscience education to address these factors prior to SCS therapy, to enhance successful outcomes in neuromodulation.
Feasibility of Mobile Application-Delivered Mindfulness Meditation for Individuals After Anterior Cruciate Ligament Reconstruction
Authors: Baez Shelby , Genoese Francesca , Reiche Elaine , Harkey Matthew , Kuenze Christopher , Moser Jason , Pietrosimone Brian
Published: December 2023

Mindfulness meditation (MM) has decreased kinesiophobia in patients with knee pathologies. Mobile application-delivered MM (Mobile MM) may reduce kinesiophobia in individuals after anterior cruciate ligament reconstructions (ACLR). The purpose of this study was to examine the feasibility (i.e., retention, adherence, and acceptability) and preliminary efficacy of a 4-week Mobile MM intervention in individuals with a history of ACLR. Nine participants ≥1 year post unilateral ACLR completed 12 sessions of Mobile MM over 4 weeks via the Headspace mobile application that were facilitated remotely through a Health Insurance Portability and Accountability ACT of 1996 (HIPAA) compliant teleconference system. Participant retention of 100% and intervention adherence of 100% were observed. Participants reported moderate to high acceptability for the Mobile MM. A large between-group effect size of 1.6 [0.13, 2.98] in the Tampa Scale of Kinesiophobia-11 change score was observed. Mobile MM is a feasible intervention to address kinesiophobia in individuals with a history of ACLR.
Raising the alarm: fosfomycin resistance associated with non-susceptible inner colonies imparts no fitness cost to the primary bacterial uropathogen
Authors: Bermudez Tomas A. , Brannon John R. , Dudipala Neha , Reasoner Seth , Morales Grace , Wiebe Michelle , Cecala Mia , DaCosta Michael , Beebout Connor , Amir Omar , Hadjifrangiskou Maria
Published: December 2023

Fosfomycin kills bacteria by blocking the binding of phosphoenolpyruvate (PEP) to the bacterial enzyme MurA and halting peptidoglycan synthesis. While fosfomycin use has increased, the mechanisms leading to fosfomycin resistance remain relatively unexplored. In uropathogenic
Escherichia coli
(UPEC) that accounts for >75% of urinary tract infections (UTIs), fosfomycin enters the cell primarily through UhpT, which transports glucose-6-phosphate (G6P) glycolysis intermediate into the cell. Mutations in
uhp
T decrease fosfomycin susceptibility and have been identified during antimicrobial susceptibility testing (AST) in non-susceptible inner colonies that form within the zone of inhibition. However, EUCAST and CLSI guidelines differ in how to read fosfomycin AST when such resistant colonies arise. We and others demonstrated that glycolysis is dispensable during acute UTI. Moreover, G6P is scarce in urine, prompting us to test the hypothesis that
uhp
mutations may not impart a fitness cost to the pathogen. We report that loss of
uhp,
indeed, does not impair UPEC pathogenesis in a well-established murine model of UTI and that clinical isolates exist that lack
uhp
altogether. Analysis of non-susceptible inner colonies revealed a suite of novel genes involved in fosfomycin resistance. One of them, PykF, converts PEP to pyruvate during glycolysis. Single deletions of
pykF
or its anaerobic homolog
pykA
do not attenuate UPEC. Based on our data, we raise the alarm that multiple routes lead to fosfomycin resistance that does not affect colonization and persistence in the host urinary tract. We propose that the current EUCAST and CLSI guidelines unify how they evaluate fosfomycin AST.

IMPORTANCE

While fosfomycin resistance is rare, the observation of non-susceptible subpopulations among clinical
Escherichia coli
isolates is a common phenomenon during antimicrobial susceptibility testing (AST) in American and European clinical labs. Previous evidence suggests that mutations eliciting this phenotype are of high biological cost to the pathogen during infection, leading to current recommendations of neglecting non-susceptible colonies during AST. Here, we report that the most common route to fosfomycin resistance, as well as novel routes described in this work, does not impair virulence in uropathogenic
E. coli
, the major cause of urinary tract infections, suggesting a re-evaluation of current susceptibility guidelines is warranted.
Mutations in genes
lpxL1
,
bamA
, and
pmrB
impair the susceptibility of cystic fibrosis strains of
Pseudomonas aeruginosa
to murepavadin
Authors: Ghassani Aya , Triponney Pauline , Bour Maxime , Plésiat Patrick , Jeannot Katy ,   MucoMicrobes study Group, Cardot-Martin Emilie , Cattoir Vincent , Crémet Lise , Doléan-Jordheim Anne , Ferroni Agnès , Garnier Fabien , Guet-Revillet Hélène , Guillard Thomas , Hery-Arnaud Geneviève , Imbert Guenièvre , Mariani Patricia
Published: December 2023

Murepavadin is a peptidomimetic exhibiting specific inhibitory activity against
Pseudomonas
species. In the present study, its
in vitro
activity was assessed on 230 cystic fibrosis (CF) strains of
Pseudomonas aeruginosa
isolated from 12 French hospitals, in comparison with 12 other antipseudomonal antibiotics. Although murepavadin is still in preclinical stage of development, 9.1% (
n
= 21) of strains had a minimum inhibitory concentration (MIC) >4 mg/L, a level at least 128-fold higher than the modal MIC value of the whole collection (≤0.06 mg/L). Whole-genome sequencing of these 21 strains along with more susceptible isogenic counterparts coexisting in the same patients revealed diverse mutations in genes involved in the synthesis (
lpxL1
and
lpxL2
) or transport of lipopolysaccharides (
bamA
,
lptD
, and
msbA
), or encoding histidine kinases of two-component systems (
pmrB
and
cbrA
). Allelic replacement experiments with wild-type reference strain PAO1 confirmed that alteration of genes
lpxL1
,
bamA,
and/or
pmrB
can decrease the murepavadin susceptibility from 8- to 32-fold. Furthermore, we found that specific amino acid substitutions in histidine kinase PmrB (G188D, Q105P, and D45E) reduce the susceptibility of
P. aeruginosa
to murepavadin, colistin, and tobramycin, three antibiotics used or intended to be used (murepavadin) in aerosols to treat colonized CF patients. Whether colistin or tobramycin may select mutants resistant to murepavadin or the opposite needs to be addressed by clinical studies.
Comparison of
Clostridioides difficile
nucleic acid amplification test (NAAT) results using fresh and frozen stool specimens and rectal swabs
Authors: Dumm Rebekah E. , Burnham Carey-Ann D. , Hink Tiffany , Reske Kimberly A. , Struttmann Emily , Iqbal Zainab Hassan , Cass Candice , Kwon Jennie H. , Olsen Margaret A. , Dubberke Erik R.
Published: December 2023

Nucleic acid amplification tests (NAATs) are frequently used in
Clostridioides difficile
research and diagnostic testing, but the effect of freezing specimens on
C. difficile
NAAT performance is not well characterized. We compared
C. difficile
NAAT results between fresh and frozen fecal (
n
= 354) and rectal swab specimens (eSwab) (
n
= 132) using the Xpert system. Specimens were collected prospectively from 384 hospitalized patients admitted to the hematopoietic cell transplant and acute leukemia wards at a tertiary care hospital. Categorical concordance of NAAT results (agreement of positive/positive or negative/negative) was excellent between fresh and frozen conditions for fecal specimens (Kappa = 0.92) and very good for rectal swabs (Kappa = 0.78). Cycle threshold value correlation was similarly consistent between fresh and frozen conditions for swabs and stool specimens (Spearman’s correlation = 0.88). These results support the use of frozen fecal and rectal swab specimens to provide accurate results for research purposes when
C. difficile
NAAT testing on fresh specimens is not available or feasible.

IMPORTANCE

Nucleic acid amplification tests (NAATs) are frequently used in
Clostridioides difficile
research and diagnostic testing, but the effect of freezing specimens on
C. difficile
NAAT performance is not well characterized. This study evaluated the concordance of NAAT results between fresh and frozen specimens (fecal and rectal swabs) and found it to be very good to excellent. The results indicate that frozen fecal and rectal swab specimens may be used for
C. difficile
NAAT testing in research when fresh specimens are not available.
Changes in lipid composition of host-derived extracellular vesicles following
Salmonella
infection
Authors: Emerson Lisa E. , Mosby Chanel A. , Enslow Samantha , Hui Winnie W. , Jones Melissa K. , Ferraro Mariola J.
Published: December 2023

Extracellular vesicles are small membrane-bound structures secreted by host cells that are involved in a variety of functions and the transmission of cargo. Vesicular cargo contains a variety of biomolecules, including lipids. Limited research has focused on the cargo content of extracellular vesicles during infections, particularly the alterations in lipid cargo that occur following bacterial infections. Our study investigates the lipid composition of extracellular vesicles generated by RAW 264.7 macrophages before and after infection with
Salmonella enterica
serovar Typhimurium at 24 and 48 hours post-infection. Our results reveal that both time and infection conditions significantly alter specific lipids in host-derived small extracellular vesicles. The altered lipids primarily comprise glycerophospholipids, sphingolipids, and prenol lipids. Our findings have important implications for understanding molecular mechanisms underlying the trafficking of lipids to extracellular compartments during infection.

IMPORTANCE

This study delves into the previously unexplored territory of extracellular vesicle (EV) cargo and composition, specifically focusing on lipid composition changes in EVs following
Salmonella
infection. EVs play crucial roles in intercellular communication, carrying a variety of biomolecules. Investigating how these EV cargo lipids change post-infection with
Salmonella
is significant for understanding the molecular mechanisms underlying lipid trafficking during infection. Given the impact of lipid composition on EV function, this research uncovers distinct differences in the lipid profiles of EVs at different time points post-infection and between infected and uninfected macrophages. This study identified lipids that are differentially abundant in EVs produced by the host during infection, offering novel insights into the dynamics of lipid profiles in EVs during cellular processes and infections. This work advances our understanding of host-pathogen interactions, specifically lipid-mediated EV functions during infection.
Metabolic and transcriptional activities underlie stationary-phase
Pseudomonas aeruginosa
sensitivity to Levofloxacin
Authors: Hare Patricia J. , Gonzalez Juliet R. , Quelle Ryan M. , Wu Yi I. , Mok Wendy W. K.
Published: December 2023

The ubiquitous opportunistic pathogen
Pseudomonas aeruginosa
is highly adaptive and refractory to several different classes of antibiotics. However, we found in this study that stationary-phase
P. aeruginosa
cultures exhibit greater sensitivity to the fluoroquinolone Levofloxacin (Levo) than other bactericidal antibiotics, including an aminoglycoside (Tobramycin) and β-lactam (Aztreonam). To understand the basis of this sensitivity, we conducted time-lapse fluorescence microscopy experiments of cells during Levo treatment. We discovered that stationary-phase
P. aeruginosa
cells die rapidly during treatment and undergo heterogeneous morphological changes, including explosive lysis, filamentation, and gradual loss of membrane integrity as evidenced by propidium iodide uptake. These morphologies are reminiscent of how the model organism
Escherichia coli
appears when recovering from fluoroquinolone treatment, a period when activation of the DNA damage-induced SOS response is crucial. Accordingly, we monitored the morphologies and survival of
P. aeruginosa
Δ
recA
mutants and found that the SOS response is not involved in
P. aeruginosa
Levo sensitivity like it is for
E. coli
. We hypothesized that Levo sensitivity may be due to
P. aeruginosa
maintaining active metabolism in stationary phase. We determined that stationary-phase
P. aeruginosa
cells transcribe, maintain reductase activity, and accumulate reactive metabolic species which contribute to Levo-mediated death. By elucidating how
P. aeruginosa
cells sustain metabolic activity during the stationary phase, we can design strategies to sensitize these persistent subpopulations to Levo and maintain the efficacy of this clinically important fluoroquinolone antibiotic.

IMPORTANCE

The bacterial pathogen
Pseudomonas aeruginosa
is responsible for a variety of chronic human infections. Even in the absence of identifiable resistance mutations, this pathogen can tolerate lethal antibiotic doses through phenotypic strategies like biofilm formation and metabolic quiescence. In this study, we determined that
P. aeruginosa
maintains greater metabolic activity in the stationary phase compared to the model organism,
Escherichia coli
, which has traditionally been used to study fluoroquinolone antibiotic tolerance. We demonstrate that hallmarks of
E. coli
fluoroquinolone tolerance are not conserved in
P. aeruginosa
, including the timing of cell death and necessity of the SOS DNA damage response for survival. The heightened sensitivity of stationary-phase
P. aeruginosa
to fluoroquinolones is attributed to maintained transcriptional and reductase activity. Our data suggest that perturbations that suppress transcription and respiration in
P. aeruginosa
may actually protect the pathogen against this important class of antibiotics.
U-Th-Pb dating, trace elements, and Sr-Nd isotopes of monazite and allanite as recorders for multi-stage rare earth element mineralization and remobilization in carbonatite dike systems
Authors: Zhang Hao-Xiang , Jiang Shao-Yong , Liu Si-Qi , Yuan Feng , Chen Wei , Su Hui-Min
Published: December 2023

Carbonatite hosts the most important rare earth resources in the world, but the precise timing, ore-forming history, and mechanism of rare earth mineralization in carbonatite systems are still in debate. Here, we report a rare corona texture of monazite-allanite-fluorapatite from the Huangjiagou carbonatite in the Lesser Qinling of central China, and demonstrate that the U-Th-Pb dating, trace elements, and Sr-Nd isotopes of these minerals in the corona are useful tools to unravel multiple-stage events for rare earth element (REE) mineralization and mobilization. The first mineralization event took place at ca. 219 Ma as revealed by the monazite U-Pb age, the same as regional carbonatite forming ages, but the Th-Pb age has been disturbed, which shows a negative correlation with Th contents. The second mineralization event occurred at ca. 128 Ma, as revealed by in situ U-Pb dating of allanite, coeval with the intrusions of neighboring I-type granite. The initial Sr-Nd isotope ratios of allanite show a downtrend from the center to the rim of monazite-allanite-apatite coronas to approach the ratios of neighboring granite, indicating an increasing effect by the metasomatism of magmatic-hydrothermal fluids during the growth of these REE-mineral coronas. Therefore, a two-episode REE mineralization was recognized with the replacement of ca. 219 Ma monazite by ca. 128 Ma allanite-apatite coronas on the function of magmatic-hydrothermal fluid metasomatism, and this process accompanies the disturbance of Th/Pb geochronology in monazite. Allanite as the product of monazite dissolution can represent the later-stage REE mineralization tracing the REE reworking processes under the hydrothermal conditions in carbonatite systems. Our study highlights the implication of monazite-allanite-fluorapatite coronas on the REE remobilization and mineralization in carbonatite systems.
Differentiation and convection in a magma chamber: Novel insights on the origin of mafic microgranular enclaves in the Tongkeng pluton, Xiaojiang area, SE China
Authors: Zhang Ruo-Xi , Yang Shui-Yuan , Jiang Shao-Yong , Fu Bin , Cui Ji-Qiang
Published: December 2023

Mafic microgranular enclaves (MMEs), commonly found in granitoid intrusions, can provide unique perspectives on the nature of magma sources and evolution, physicochemical properties of magmas, and geotectonic dynamic evolution. However, their origin and generation remain under debate. In this paper, the Cretaceous Tongkeng pluton with MME occurrence located in the Xiaojiang area of Zhejiang Province, SE China, was examined. Zircon U-Pb dating indicates that the gabbroic diorite, MMEs, and their host quartz diorite all crystallized at 107–106 Ma. All samples from the Tongkeng pluton show a comparable range of initial 87Sr/86Sr values (0.70746–0.70841), εNd(t) values (−4.9 to −2.9), and zircon εHf(t) values (−7.3 to −2.9) with the peak value of −6 to −4. In addition, Pb isotope compositions are fairly consistent. Petrology, geochemical and isotopic compositions, and geochemical modeling suggest that the gabbroic diorite, MMEs, and their host rock were cognate and their primary magma was derived from the mixing between a mantle-derived magma and a crustal magma. The “magma differentiation and convection” model, proposed in this paper to improve our understanding of the origin of the MMEs and their host rock, suggests that the gabbroic and quartz dioritic magmas were formed by cognate magma differentiation, and the MME magma is a portion of the gabbroic dioritic magma that is incorporated into and mingled with the quartz dioritic magma. Misjudgment in the origin and generation of MMEs leads to an erroneous understanding of mantle properties, the genesis of granitoids, and therefore, many other geological processes. Hence, caution is needed when considering the relationship between the host granitoid and its associated MMEs with similar chemical and isotopic compositions, particularly for those exposed in areas where mafic rocks are absent (or undiscovered).
Supplemental Material: A record of Late Cretaceous to early Paleogene Insular terrane accretion within the Northern Cordillera: Insights from monazite petrochronology across the Kluane Schist, southwest Yukon, Canada
Authors: McKenzie Will , et al.
Published: December 2023

All raw monazite U-Th-Pb age and trace element data, mineral compositional data, calculated whole rock compositions, Ti-in-biotite thermometry, additional x-ray (AMICS) phase maps, monazite backscatter electron images, additional phase diagrams calculated with different dataset/activity end-member combinations, T-XH2O diagram, full phase diagrams that contribute to Figure 7A in main text, monazite trace element spider diagrams, and an example rim-to-rim garnet profile from a Kluane Schist sample.
Quantum Size Effect in Three-Dimensional Microscopic Semiconductor Crystals
Authors: Ekimov A. I. , Onushchenko A. A.
Published: December 2023

The exciton absorption spectrum of microscopic CuCl crystals grown in a transparent dielectric matrix has been studied. The size of the microscopic crystals was varied in a controlled manner from several tens of angstroms to hundreds of angstroms. There is a short-wave shift (of up to 0.1 eV) of the exciton absorption lines, caused by a quantum size effect.
Gene of the month:VSTM2A
Authors: Wang Lisha , Yilmaz Osman , Veeneman Brendan A , Zhang Yuping , Dhanasekaran Saravana M , Mehra Rohit
Published: December 2023

The V-set and transmembrane domain containing 2A (VSTM2A)gene is located on chromosome 7. In the physiological state, VSTM2A regulates preadipocyte cell differentiation.VSTM2Ais highly expressed in normal human brain tissue and minimally expressed in other normal tissues. Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a distinct renal tumour subtype with signature chromosomal copy number alterations and an indolent outcome in the majority of cases.VSTM2Aoverexpression is highly enriched in this renal cancer subtype and has been shown to have potential diagnostic value in distinguishing MTSCC from renal tumours with overlapping histological appearances.
Experimental study on deformation and failure of a mining slope under the action of rainfall
Authors: Tao Tongwei , Shi Wenbing , Xiong Shaozheng , Liang Feng , Zhang Jiayong
Published: December 2023

On 28 August 2017, a mining slope collapse in Pusa Village, Guizhou Province, China, resulted in the release of ~8600 m3 of earth and rock, leading to 35 fatalities. The deformation and failure mechanisms of the mining slope under the influence of rainfall was studied by a physical model test, using the Pusa Village collapse as an example. Data were collected through strategically placed monitoring points in a physical model, forming the basis for a quantitative analysis of slope deformation and failure patterns. The tested results revealed that sequential mining and rainfall activities induce progressively increasing stress variations, exhibiting a cyclical pattern of stress concentration, relaxation, and stabilization. Mining activities initiated the formation of tension and separation fractures within the model, which were subsequently exacerbated by rainfall. Rainwater infiltrating through these fractures and geotechnical bodies resulted in a more pronounced increase in water content in the upper part of the model than in the lower part. Displacement values within the model progressively increased with ongoing coal seam mining, primarily occurring in the mining area's roof and extending to the model's top following rainfall. The failure mode of the Pusa slope under combined mining and rainfall conditions is characterized by the following sequence: bending-pulling-subsidence-creep-dumping. The deformation and failure processes can be categorized into four stages: mining-induced disturbances, fractures extension and extension, formation of a potential collapse surface, and destabilization failure.
The role of melatonin in preventing amiodarone-induced rat liver damage
Authors: Petrović Dejan , Ilić Marina Deljanin , Simonović Dejan , Stojanović Milovan , Stanković Milica , Stanišić Slaviša , Stojanović Sanja , Arsić Nebojša , Sokolović Dušan T.
Published: December 2023

Long-term exposure to amiodarone, an antiarrhythmic drug, can induce different organ damage, including liver. Cell damage included by amiodarone is a consequence of mitochondrial damage, reactive oxygen species production, and cell energy depletion leading to programmed cell death. In the present study, hepatoprotective potential of neurohormone melatonin (50 mg/kg/day) was evaluated in a chronic experimental model of liver damage induced by a 4-week application of amiodarone (70 mg/kg/day). The obtained results indicate that amiodarone induces an increase in xanthine oxidase activity, as well as the content of the lipid and protein oxidatively modified products and p53 levels. Microscopic analysis further corroborated the biochemical findings revealing hepatocyte degeneration, apoptosis, and occasional necrosis, with the activation of Kupffer cells. Coadministration of melatonin and amiodaron prevented an increase in certain damage associated parameters, due to its multiple targets. In conclusion, the application of melatonin together with amiodarone prevented an increase in tissue oxidative damage parameters and moderately prevented liver cell apoptosis, indicating that the damage of hepatocytes provoked by amiodarone supersedes the protective properties of melatonin in a given dose.
A Prospective Study of Graft Repositioning over Flap Technique for Reconstruction of Fingertip Amputation
Authors: KALADAGI Nitin , MANAS Raj Kumar
Published: December 2023

Background: Replantation of digital tip amputations, especially Allen III and IV, is challenging for hand surgeons as it requires a high level of microsurgical expertise and fine instruments. The graft repositioning over flap (GRF) technique is a simple and reliable procedure that provides length, sensation and nail growth and GRF has become popular in the last few years. The aim of this study is to report the short-term outcomes of the GRF technique.

Methods: This is a prospective study of all patients who underwent a GRF reconstruction for Allen III and IV digital amputations at our hospital over a 12-month period. In addition to demographic data and injury details, we collected outcomes data with regard to flap and nailbed graft survival, capillary refill time, nail growth, sensation (2-point discrimination), bone union and gain in length of digit compared to length at injury.

Results: Twenty patients underwent GRF reconstruction of digital amputation. They included 18 men and 2 women with an average age of 29 years. The thumb was the most frequently injured digit (n = 7). Electric saws (n = 5) and industrial machines (n = 5) accounted for 50% of injuries. Twelve amputations were Allen IV. Five patients were lost to follow-up and outcomes data was available for 15 patients. There was loss of flap and nail bed in three patients. There was no growth of nail in three patients. The distal phalanx graft was lost in six patients and united in the remaining nine patients.

Conclusions: The GRF technique is a simple and reliable option in patients in whom replantation is not possible. It restores length, provides sensation and nail growth in the reconstructed fingers.

Level of Evidence: Level IV (Therapeutic)