Critical Time Research Articles

On the self-similarity of unbounded viscous Marangoni flows

The Marangoni flow induced by an insoluble surfactant on a fluid–fluid interface is a fundamental problem investigated extensively due to its implications in colloid science, biology, the environment and industrial applications. Here, we study the limit of a deep liquid subphase with negligible inertia (low Reynolds number, $Re\ll {1}$ ), where the two-dimensional problem has been shown to be described by the complex Burgers equation. We analyse the problem through a self-similar formulation, providing further insights into its structure and revealing its universal features. Six different similarity solutions are found. One of the solutions includes surfactant diffusion, whereas the other five, which are identified through a phase-plane formalism, hold only in the limit of negligible diffusion (high surface Péclet number $Pe_s\gg {1}$ ). Surfactant ‘pulses’, with a locally higher concentration that spreads outward, lead to two similarity solutions of the first kind with a similarity exponent $\beta =1/2$ . On the other hand, distributions that are locally depleted and flow inwards lead to similarity of the second kind, with two different exponents that we obtain exactly using stability arguments. We distinguish between ‘dimple’ solutions, where the surfactant has a quadratic minimum and $\beta =2$ , from ‘hole’ solutions, where the concentration profile is flatter than quadratic and $\beta =3/2$ . Each of these two cases exhibits two similarity solutions, one valid prior to a critical time $t_*$ when the derivative of the concentration is singular, and another one valid after $t_*$ . We obtain all six solutions in closed form, and discuss predictions that can be extracted from these results.

Amputated life-testing based on extended Dagum percentiles for type of group inspection plans: optimal sample sizes, termination time ratios analysis

This paper introduces a novel approach to life-testing using Extended Dagum (EXD) percentiles within the framework of group inspection plans. The methodology focuses on optimizing sample sizes and analyzing termination time ratios to enhance the reliability of quality control procedures. By leveraging the flexibility of the EXD distribution, the proposed approach accurately models complex survival data, accommodating heavy-tailed characteristics often encountered in practice. The study presents a detailed analysis of optimal sample sizes and the critical termination time ratios that balance producer and consumer risks. Through comprehensive simulations and real applications, the paper demonstrates the effectiveness of the proposed methodology in ensuring robust and efficient life-testing strategies, offering valuable insights for practitioners in industries such as manufacturing, engineering, and reliability analysis.

The excessive tonic inhibition of the peri-infarct cortex depresses low gamma rhythm power during post-stroke recovery.

The cortex immediately surrounding a brain ischemic lesion, the peri-infarct cortex, harbors a large part of the potential to recover lost functions. However, our understanding of the neurophysiological conditions in which synaptic plasticity operates, remains limited. Here we hypothesized that the chronic imbalance between excitation and inhibition of the peri-infarct cortex prevents the normalization of the gamma rhythm, a waveband of neural oscillations thought to orchestrate action potential trafficking. Probing the local field potential activity of the forelimb primary sensory cortex (S1FL) located in the peri-infarct cortex of male adult mice, we found a constant, deep reduction of low-gamma oscillation power (L-gamma; 30-50 Hz) precisely during the critical time window for recovery (1 to 3 weeks after stroke). The collapse of L-gamma power negatively corelated with behavioral progress in affected forelimb use. Mapping astrocyte reactivity and GABA-like immunoreactivity in the peri-infarct cortex revealed a parallel high signal, which gradually increased when approaching the lesion. Increasing tonic inhibition with local infusion of GABA or by blocking its recapture reduced L-gamma oscillation power in a magnitude similar to stroke. Conversely, the negative allosteric modulation of tonic GABA conductance using L655,708 or the gliopeptide ODN rescued the L-gamma power of the peri-infarct cortex. Altogether the present data point-out that the chronic excess of ambient GABA in the peri-infarct cortex limits the generation of L-gamma oscillations in the repairing cortex and suggests that rehabilitative interventions aimed at normalizing low-gamma power within the critical period of stroke recovery could optimize the restitution of lost functions.Significance Statement After a stroke, the recovery of lost motor function depends on the reorganization of surviving neural networks. However, the excitation/inhibition balance in the repairing area is suboptimal as it leans excessively towards inhibition. In this work, using an in vivo approach, we demonstrate here that this imbalance, occurring during the critical window for recovery, leads to the collapse of gamma oscillations, a crucial cerebral rhythm for organizing neural communication. This study reinforces the concept of timely therapeutic interventions aimed at correcting the pathological oscillatory regimen of stroke recovery to enhance plasticity.

Multiple Episodes of Late Neoproterozoic Rifting in the Tarim Craton During Its Separation from the Supercontinent Rodinia

In this paper, we review and evaluate the magmatic history, regional stratigraphy, structural patterns, and sedimentary provenance features of the Late Neoproterozoic Tarim Craton to elucidate the nature and different modes of extensional tectonics during the Latest Neoproterozoic, a critical time coinciding with the disintegration of the Supercontinent Rodinia. New detrital zircon U-Pb ages and geochemical data acquired from quartz schists and spatially associated granites in the Tugerming anticline along the northern margin of the Tarim Craton have revealed Cryogenian ages, as opposed to Early Neoproterozoic and older ages as reported in previous studies. Granitic intrusions are dated at 656 – 637 Ma, which involved remelting of the ancient crust following the decline of the initial (Cryogenian) rift stage. They are unconformably overlain by terrestrial clastic deposits. Based on the available detrital zircons from the Late Neoproterozoic sedimentary rock assemblages, we identify a major change in the provenance of the basinal strata at the end of the Cryogenian Period. This inferred provenance change, associated with basement exhumation, overlaps in time with resumed magmatic activities, basin inversion and uplift along the northern margin of the craton. The initial, Cryogenian rifting stage was facilitated by pure shear deformation that produced rift basins in and across the Tarim Craton. The subsequent rifting stage was facilitated by simple shear deformation, confined to the northern edge of the craton as the breakup of the Supercontinent Rodinia further progressed. Episodic rifting of the Tarim Craton and its separation from Rodinia were aided by thermal weakening of its lithosphere due to the periodic impingement of mantle upwelling beneath it throughout the Cryogenian and Ediacaran Periods.

Copyist or Creative? The Emergence of the Woman Fashion Artist in Britain, 1880–1920

Abstract The period between 1880 and 1914 was a critical time for the redefinition of high fashion as a form of art, with couture garments displayed at international exhibitions and couturiers like Paul Poiret claiming the legal protection applied to artworks for his fashion designs. At the same time, a massive expansion in illustrated journals and catalogs selling mass-produced garments offered new possibilities for graphic artists, including women trained in the applied arts by public and private colleges. These trends intersected in the figure of the female “fashion artist,” who conceived new designs or presented them to the public—but did not stitch them. In some cases, this person was a designer working for a dressmaking firm or sample house, while others were copyists of existing garments. This article will analyze surviving documents produced by British women fashion artists; examine the life cycle of fashion artists, as revealed in census data; analyze the pathways for training and career development; and consider the ways in which fashion artists were discussed in women’s magazines, both as role models for employment and as fashion mediators.

Changes in the problem and subject field of labor sociology against the backdrop of the time challenges (Based on publications in the journal “Sociological Studies” over 50 years)

Trends in the problem and subject field of labor sociology were identified by referring to the Sociological Studies journal publications for 1974–2023. An array of 351 articles on labor sociology was selected for qualitative and quantitative content analysis. Eleven problematic subject areas of research were identified by the criterion of the leading target of the article’s text. Fourtime frames in Russian society and economic development over the past 50 years have been distinguished to identify the time challenges that vary in content. Each period was provided with a brief description of the content of the research problem and subject areas, as well as interpretations thereof with due consideration of the time challenges. Analysis of the publications permitted to reveal that by the criteria of how frequent and stable the sociologists’ referrals to the selected areas have been, the core, the margins, and the mobile realm may be identified in the Russian sociology of labor. The core is formed by the areas related to the studies of labor attitudes, labor incentives, labor values, employee behavior, and job satisfaction. The areas – whose principal object of study is labor itself, along with its role and significance in both the society and the employees’ values as well as social problems of work at the enterprise – are adjacent to the core. The margins are formed by rare areas of research such as the workers’ capacity to act, manifestations of independence and involvement in the organization’s affairs, problems of the socioeconomic standing of workers and degree of labor protection, labor culture, shortage and reproduction of workers. The mobile realm of labor sociology is composed by the areas treated generally depending on the context of time and the aggravation of particular problem situations (labor organization, labor relations, precarity of labor, etc). We observed adequate coverage of the critical time challenges in publications in all those time frames; however, that coverage was reactive and appeared to lack forward-looking ideas that are ahead of theory and practice.

Partnership quality and maternal depressive symptoms in the transition to parenthood: a prospective cohort study

BackgroundPregnancy and childbirth are critical life events which lead to significant changes in family structures and roles, thus having a substantial impact on partner relationship and maternal wellbeing. A dysfunctional partnership during this critical time of life has been associated with maternal depressiveness. However, sub-components of partnership quality and the causal relation with maternal symptoms of depression in the perinatal period have been sparsely studied so far. The current study aims to longitudinally assess the course of relationship quality and its sub-components from pregnancy to postpartum and to test a potential causal association with maternal symptoms of depression in the perinatal period.MethodsDiffering from previous studies, partnership quality and symptoms of depression have been assessed prospectively and longitudinally from an early stage of pregnancy (second trimester) until six months postpartum. Cross-lagged panel models were applied to investigate a potential causal relationship between partnership quality and maternal depressive symptoms.ResultsRelationship quality decreased significantly during the transition to parenthood (p < .05) with the steepest decline referring to tenderness (p < .001). We also found a substantial association of relationship quality and maternal depressiveness, but no indication for a clear causal direction of this association.ConclusionsOur results suggest that relationship quality and maternal depressiveness are substantially related in the perinatal period, thus pointing to the need of early prevention and intervention programs for peripartum women and their partners to prevent adverse outcome for the couple and the family.

Differential transcriptomic host responses in the early phase of viral and bacterial infections in human lung tissue explants ex vivo

BackgroundThe first 24 h of infection represent a critical time window in interactions between pathogens and host tissue. However, it is not possible to study such early events in human lung during natural infection due to lack of clinical access to tissue this early in infection. We, therefore, applied RNA sequencing to ex vivo cultured human lung tissue explants (HLTE) from patients with emphysema to study global changes in small noncoding RNA, mRNA, and long noncoding RNA (lncRNA, lincRNA) populations during the first 24 h of infection with influenza A virus (IAV), Mycobacterium bovis Bacille Calmette-Guerin (BCG), and Pseudomonas aeruginosa.ResultsPseudomonas aeruginosa caused the strongest expression changes and was the only pathogen that notably affected expression of microRNA and PIWI-associated RNA. The major classes of long RNAs (> 100 nt) were represented similarly among the RNAs that were differentially expressed upon infection with the three pathogens (mRNA 77–82%; lncRNA 15–17%; pseudogenes 4–5%), but lnc-DDX60-1, RP11-202G18.1, and lnc-THOC3-2 were part of an RNA signature (additionally containing SNX10 and SLC8A1) specifically associated with IAV infection. IAV infection induced brisk interferon responses, CCL8 being the most strongly upregulated mRNA. Single-cell RNA sequencing identified airway epithelial cells and macrophages as the predominant IAV host cells, but inflammatory responses were also detected in cell types expressing few or no IAV transcripts. Combined analysis of bulk and single-cell RNAseq data identified a set of 6 mRNAs (IFI6, IFI44L, IRF7, ISG15, MX1, MX2) as the core transcriptomic response to IAV infection. The two bacterial pathogens induced qualitatively very similar changes in mRNA expression and predicted signaling pathways, but the magnitude of change was greater in P. aeruginosa infection. Upregulation of GJB2, VNN1, DUSP4, SerpinB7, and IL10, and downregulation of PKMYT1, S100A4, GGTA1P, and SLC22A31 were most strongly associated with bacterial infection.ConclusionsHuman lung tissue mounted substantially different transcriptomic responses to infection by IAV than by BCG and P. aeruginosa, whereas responses to these two divergent bacterial pathogens were surprisingly similar. This HLTE model should prove useful for RNA-directed pathogenesis research and tissue biomarker discovery during the early phase of infections, both at the tissue and single-cell level.

“The flames are 50/50 right now”: content moderation practices at the onset of the HIV/AIDS epidemic in the United States (1982–1990)

The timeline for the onset of the HIV/AIDS epidemic in the United States occurred parallel to the domestic shift of computing and the advent of DIY computer networking efforts. During this critical time, many activists and community organisers within lesbian, gay, bisexual, transgender, and queer (LGBTQ+) spaces utilised computer networking, such as bulletin board systems (BBSs) and Usenet boards to facilitate information exchange within their affected communities. Due to the sensitive nature of the epidemic and often-vital need for up-to-date information, content moderation became an increasingly important issue on these boards. This paper uses varying archival methods to explore the development of content moderation practices, and the influence of HIV/AIDS culture, on bulletin board systems and Usenet boards, with a special focus on boards dedicated to LGBTQ+ content and HIV/AIDS information exchange.

Origins of British reservoir safety legislation 1850-1930

One hundred years ago in 1925 there were two dam failures with significant loss of life and following these disasters the 1930 Reservoirs (Safety Provisions) Act was enacted. Catastrophic failures in the nineteenth century had produced demands for government action but legislation had been much delayed by changes of government at critical times and by concerns about inadvertently reducing legal liability of reservoir owners. Also there was a marked lack of enthusiasm within the civil engineering profession for a government inspectorate. The key feature of the 1930 Act was that reservoir owners were required to appoint qualified civil engineers to inspect their reservoirs and, following such inspections, to implement measures required in the interests of safety. Post-1930 legislation, which it is intended will be the subject of a further paper, has done much to enhance public safety but the fundamental importance of independent qualified civil engineers has not diminished.

Comparison of intestinal and pharyngeal microbiota in preterm infants on the first day of life and the characteristics of pharyngeal microbiota in infants delivered by cesarean section or vaginally.

This study aimed to explore the distribution of intestinal and pharyngeal microbiota on the first day of life in preterm infants and compare the composition of microbiota in infants delivered by cesarean section or vaginally. This study included 44 late preterm infants with a gestational age of 34-36 + 6 weeks. Stool and throat swab samples were collected from the preterm infants on the first day of life. The infants were divided into cesarean section and vaginal delivery groups. Illumina NovaSeq high-throughput sequencing technology was used to sequence the V3-V4 hypervariable region of the 16S rRNA gene of all bacteria in the samples. Venn diagram was used to identify shared operational taxonomic units (OTUs) in the intestines and pharynges. Microbial analysis was conducted at the phylum and genus levels, and α and β diversity comparisons were performed. (1) Gestational age may have significantly affected the microbial colonization of the intestines and pharynges of preterm infants on the first day after birth (p ≤ 0.001). (2) More OTUs were detected in the pharynx than in the intestines, both have a total of 819 shared OTUs. Proteobacteria, Firmicutes, and Bacteroidota were the dominant phyla in both. At the genus level, Streptococcus had a lower relative abundance in stool samples (0.5%) compared to throat samples (0.5% vs. 22.2%, p = 0.003). 3) The relative abundance of Streptococcus in pharyngeal samples was 26.2% in the cesarean section group much higher than the 3.8% in the vaginal delivery group (p = 0.01). The early postnatal period is a critical time for the establishment of an infant's microbiota. Gestational age at birth may influence microbial colonization, while birth weight, gender, and mode of delivery do not. The intestinal and pharyngeal microbiota composition of preterm infants on the first day after birth showed high similarity, but larger samples are needed for further validation.

Beyond Conventional Imaging: A Systematic Review and Meta-Analysis Assessing the Impact of Computed Tomography Perfusion on Ischemic Stroke Outcomes in the Late-Window.

Non-contrast CT (NCCT) and CT angiogram (CTA) have become essential for endovascular treatment (EVT) in acute stroke. Patient selection may improve when CT perfusion imaging (CTP) is also added for patient selection. We aimed to analyze the effects of implementing CTP in acute ischemic stroke (AIS) patients' treatment to assess whether stroke outcomes differ in the late window. We searched the PubMed, Embase, and Web of Sciences databases to obtain articles related to CTA and CTP in EVT. Collected patient data was split into two groups: the CTP and control (NCCT+CTA) cohorts. Primary outcomes evaluated were modified Rankin Scale (mRS) scores, symptomatic intracranial hemorrhages (sICH), mortality, and successful recanalization. There were 14 studies with 5,809 total patients in the final analysis: 2,602 received CTP and 3,202 were in the control group. CTP/CTA patients showed significantly lower rates of 90-day stroke-related mortality (OR: 0.72, 95% CI 0.60-0.87, p<0.01) and significantly higher successful recanalization (OR: 1.42, 95% CI 1.06-1.94, p<0.01) compared to CTA-only patients. Analysis of other outcomes including functional independence (mRS 0-2), critical times, and intracranial hemorrhages were non-significant (p > 0.05). The study highlights the usefulness of CTP-guided therapy as a supplementary tool in EVT selection in the late window. Although the addition of CTP resulted in lower mortality, the favorable outcomes did not improve. Further evidence is required to establish a clearer understanding of the potential advantages or limitations of incorporating CTP in stroke imaging.

Demonstration of a physical inversion scheme for all-sky, day-night IASI observations and application to the analysis of the onset of the Antarctica ozone hole: Assessment of retrievals and consistency of forward modeling

Based on a recently developed all-sky forward model (σ-IASI/F2N) for the computation of spectral radiances in the range 100 to 2760 cm-1, the paper addresses the spring onset of the Antarctica ozone hole with infrared observations from the IASI (Infrared Atmospheric Sounder Interferometer) satellite sounder. The Antarctica ozone hole is a cyclic event that grows in normal conditions in late August and collapses in late November/early December. Because of climate change (cooling of the stratosphere), the O3 hole is expected to become deeper. Indeed, 2021 and 2023 have been characterized by very spatially extensive and deep ozone hole. To demonstrate that we can gain further insights into these phenomena with the help of infrared nadir viewing observations, we have developed an all-sky retrieval tool, which inverts the whole IASI infrared spectrum to simultaneously estimate thermodynamic and geophysical parameters, including ozone and nitric acid, which are key parameters in analyzing the Antarctic ozone hole. Infrared sounders acquire data day and night, unlike visible and ultraviolet sounders, which are only operational during daytime. This enables us to acquire data also during the polar night, which is a critical time for O3 hole formation. Ice polar stratospheric clouds have been identified and fitted with our scheme. Maps of atmospheric ozone, complemented with those of nitric acid, temperature, and lower stratosphere height, have been retrieved for July, September, and October 2021 and 2023. Results are compared to those derived from TROPOMI (TROPOspheric Monitoring Instrument) and OMI (Ozone Monitoring Instrument), showing a very good agreement. The comparison of simultaneously retrieved O3 and HNO3 shows that the onset of the ozone hole is associated with relevant denitrification in the Antarctica Stratosphere. For 2023, our findings also show that O3 depletion episodes began as early as July. Although demonstrative, our analysis evidences the importance of Numerical Weather Prediction centers to assimilating all-sky infrared radiances (day, night, clear, or with ice or water clouds) to get insights into providing a more comprehensive picture of the Southern Spring ozone depletion over Antarctica.

Timing of intravenous immunoglobulin treatment and outcome in Guillain-Barré syndrome: Is time nerve?

Despite treatment, a considerable proportion of patients with Guillain-Barré syndrome (GBS) experience poor recovery, highlighting a therapeutic need. There is a lack of evidence that treatment timing affects recovery. This study aims to investigate the effects of intravenous immunoglobulin (IVIg) timing on disability and speed of recovery in GBS. We performed a retrospective study of 136 IVIg-treated GBS patients admitted to two Korean centers between 2010 and 2021. We analyzed the effect of time to IVIg on the GBS disability scale (GBS-DS) and the degree of improvement from nadir (∆GBS-DS) at 1, 3, 6, and 12 months, as well as the time to regain the ability to walk or run unaided. Time to IVIg was treated either as a continuous variable or categorized into 1-week intervals to explore critical time windows. Known prognostic factors, the modified Erasmus GBS Outcome Scores on admission and pre-treatment serum albumin levels were adjusted as covariates. Shorter time to IVIg was independently associated with better GBS-DS, greater ∆GBS-DS, and shorter time to walk or run unaided at all time points. The therapeutic effect of IVIg was notably diminished when administered beyond the first 2 weeks of onset. Our study highlights the timing of IVIg as a modifiable prognostic factor in GBS. The earlier IVIg is initiated, the better the outcomes, with the ideal time window being within the first 2 weeks. These findings underscore the importance of prompt diagnosis and early intervention to optimize recovery in GBS patients.

"Kuteteza": A community-engaged COVID-19 Prevention and Protection Initiative in Southern Malawi.

The COVID-19 epidemic in Malawi involved almost 90,000 recorded cases and 2,638 deaths. In response to early concerns about vulnerable older people in rural areas, we developed 'Kuteteza': a COVID-19 mitigation response project. Clinicians, public health professionals, and researchers collaborated with government and district-level staff in two Southern Malawi districts. Interventions included supported 'shielding' of older people - minimising social mixing whilst having their daily needs supported. Additional mitigation strategies included provision of masks, handwashing stations, and soap. Government partnerships allowed additional support for vulnerable groups. We present the findings of a realist project evaluation, assessing the feasibility of this approach. We collated anonymised descriptive data on Kuteteza procedures and conducted qualitative structured observations in villages involved in the initiative. We carried out three focus groups involving community members, frontline health staff, and volunteers in each setting. These provided deeper insights into experiences of the pandemic and impacts of the intervention, including suggested opportunities during future outbreaks. The project involved 25 villages across two districts, with 1,087 people over the age of 60 voluntarily participating in 'shielding'. Supplies of food, water, and cooking fuel were mostly arranged within the family. In Kuteteza villages, the handwashing stations and soap were widely used, and there was awareness and some observance of COVID-19 prevention measures. The project, including the provision of supplies, was greatly appreciated by communities, but wider contextual constraints - namely widespread economic insecurity - presented persisting challenges. Suggestions for improvement largely concerned project enhancements and extensions. Through effective stakeholder engagement and contribution to national response strategy, the Kuteteza project helped raise COVID-19 awareness and supported populations at a critical time in the pandemic. Kuteteza approaches were welcomed locally and may be incorporated in future epidemic responses. Supported 'shielding' should be paired with government-led measures to mitigate economic hardship.

Predicting the Timing and Cause of Microvascular Free Flap Failure: An Australian Study of 1569 Free Flaps.

The aim of the study is to assess the possible predictors of microvascular free flap failure and determine the critical postoperative timing of flap failure, thereby minimizing this adverse outcome. This is a retrospective single-institutional review of 1569 free flap operations. All free flaps with outcome status recorded were analyzed for possible predictors in the development of microvascular compromise. Compromised cases were then analyzed for differences in time to compromise and time to theater takeback between salvaged versus failed free flaps. Of the assessable 1569 free flaps, 31 developed microvascular compromise (2.0%); the salvage rate was 20.0%, and overall failure rate was 1.5%. Osteocutaneous free flaps in head and neck had increased risk of developing free flap failure compared to other flaps (odds ratio = 3.8, 95% confidence interval: 1.2-12.7). Among breast patients, previous radiotherapy had a significant association with flap failure ( P < 0.001). Free flap salvage rates dropped from 38.5% to 7.7% for compromises detected after 24 hours ( P = 0.160), and from 57.1% to 11.1% for free flaps taken back to theater greater than 3 hours after compromise detection ( P = 0.032). Delays in compromise detection and flap takeback to theater resulted in reduced salvage rates, with the critical timing of takeback being under 3 hours. Standardized flap monitoring protocols and incorporation of newer technologies could see faster detection and improved salvage rates. Additional care is required when reconstructing: osteocutaneous head and neck free flaps and previously irradiated breast patients.

A novel highly sensitive test reaction for micromixing: Acid‐base neutralization and alkaline hydrolysis of ethyl oxalate

AbstractMicromixing in chemical reactors can be characterized through test reactions that are sensitive to mixing. A new pair of parallel competitive reactions, including acid–base neutralization and diethyl oxalate hydrolysis, is proposed in this work. It has clear principles and high sensitivity to micromixing with quantitative accuracy and operational simplicity. The measurement results obtained from stopped‐flow spectra show that the alkaline hydrolysis of diethyl oxalate follows second‐order kinetics, and the rate constant conforms to the Arrhenius equation k2 = 2.331 × 108 exp(−26.92 × 103/RT) (L/mol/s). The estimated half‐life of hydrolysis is approximately 3 × 10−4 s under the selected concentration combinations, which provides significant advantages for the micromixing assessment in the strong turbulent fluid environment. In the same stirred tank, the critical feed time of new test reaction is shorter than that of the Villermaux–Dushman reaction. Overall, this work provides practical ideas for screening other desired esters for fast hydrolysis to construct more test reactions for micromixing.

Optimization of surgical evaluation algorithms for living donor liver transplantation

BackgroundLiving donor liver transplantation (LDLT) is an established and endorsed alternative for deceased donor liver transplantation with better recipient outcomes. Nevertheless, while extensive evaluation of potential donors is crucial, evaluation algorithms differ between transplant centres and guidelines. MethodsWe included 317 individuals evaluated for LDLT between 07/2007–07/2022 in a retrospective analysis. The evaluation process was analysed to identify the key reasons for declining 77 potential donors. Additionally, 146 donors that underwent LDLT were analysed regarding risk factors for complications. ResultsThe main reasons for donor refusal were liver volumetry (40.3 %) and metabolic factors including obesity or steatotic liver disease (20.8 %). Contrast-enhanced computed tomography (CECT) identified 63.6 % of all declined donors; CECT combined with assessment of medical history, physical examination, blood testing and ultrasonography, identified 87.0 % of declined potential donors. Associated with this selection, complication rates in donors were low (≥II in 17.1 %; none with ≥IVb). Notably, higher age was a risk factor for developing a complication ≥II after hemi-hepatectomy (p = 0.0373). ConclusionsWe propose a progressive 4-step evaluation algorithm that begins with a very basic assessment combined with up-front CECT. This early phase of testing is expected to identify nearly 90 % of ineligible donors, thereby conserving critical resources, time and money, as well as minimising burden for potential donors. FundingJ.M.W. received funding by grant We-4675/6–1 from the Deutsche Forschungsgemeinschaft (DFG) in Bonn, Germany.

Ghrelin alleviated TiO2 NPs-induced inhibition of endochondral osteogenesis and promoted longitudinal growth of long bones in juvenile rats via Wnt/β-catenin signaling pathway

Titanium dioxide nanoparticles (TiO2 NPs) are widely used in children’s daily necessities and foods, and their health hazards to children have attracted particular attention. Childhood is a critical time for accelerated bone growth and development. Current studies revealed that TiO2 NPs exposure causes bone damage in juvenile rats; however, the underlying mechanism is unknown. Ghrelin is a polypeptide hormone that is considered to be a candidate factor for regulating bone growth and development. In this research, 3-week-old juvenile male rats were administered 0, 100 or 200 mg/kg TiO2 NPs and 50 μg/kg ghrelin for 4 weeks to explore the underlying mechanism of TiO2 NPs-induced bone damage, and the protective effect of ghrelin. Our results revealed that TiO2 NPs resulted in decreased synthesis of bone growth-related hormones, disturbed bone metabolism, and destruction of bone structure. Further mechanism studies showed that TiO2 NPs inhibited Wnt/β-catenin pathway, reduced collagen synthesis, inhibited chondrocyte proliferation and differentiation, promoted chondrocyte apoptosis, and inhibited endochondral osteogenesis, ultimately leading to long bone longitudinal growth retardation and osteoporosis. Ghrelin alleviated the negative effects of TiO2 NPs-induced bone growth in juvenile rats by upregulating the Wnt/β-catenin signaling pathway. This study provided a reference for the clinical treatment of growth retardation and idiopathic short stature in juvenile children caused by environmental pollutants.

A study to reveal the rationales of overnight transfusion in a training and research hospital

BackgroundMonitoring of overnight transfusions would be beneficial to improve blood transfusion safety. The objective of this study was to prospectively evaluate the practice and need for overnight transfusions (OT) in a teaching and research hospital. MethodsThe study was conducted on data from patients who received packed red blood cells (PRBCs) transfusions between 11 September and 13 October 2023 at a Training and Research Hospital in Ankara, Turkey. Clinical data of patients were obtained from the Hospital Database Management System (HDBS) and blood transfusion order forms. The critical time point of the transfusion process was recorded using HDBS. ResultsA total of 1502 PRBCs transfusions were noted during the study period, of which 400 (26.6%) were OT. OT was most frequently administered to patients with symptomatic anemia (34.6%; 138/400) and patients with an Hb level <7 (27.7%; 111/400). The time interval in which OT was most frequently ordered was between 15:00 and 17:00 [20.2% (81/400)], while the most frequent time to start transfusion was between 17:00 and 19:00 [22% (88/400)]. The average time taken from ordering OT to starting OT was 3 hours 41 minutes. The most of patients (36.8%; 91/248) were discharged after 48 hours of transfusion or were still in the hospital for more than 48 hours (20.3%; 50/248). ConclusionTo ensure transfusion safety by reducing OT to a minimum, OT should be used only in emergencies, policies should be put in place to make sure that transfusions can be done during the day easily, and healthcare professionals should be made aware of this issue.