bluuebunny/crossref_metadata_2025 huggingface dataset:
Paternally imprinted LATE‐FLOWERING2 transcription factor contributes to paternal‐excess interploidy hybridization barriers in wheat
Authors: Yang Guanghui , Feng Man , Yu Kuohai , Cui Guangxian , Zhou Yan , Sun Lv , Gao Lulu , Zhang Yumei , Peng Huiru , Yao Yingyin , Hu Zhaorong , Rossi Vincenzo , De Smet Ive , Ni Zhongfu , Sun Qixin , Xin Mingming
Published: October 2023

Interploidy hybridization between hexaploid and tetraploid genotypes occurred repeatedly during genomic introgression events throughout wheat evolution, and is commonly employed in wheat breeding programs. Hexaploid wheat usually serves as maternal parent because the reciprocal cross generates progeny with severe defects and poor seed germination, but the underlying mechanism is poorly understood. Here, we performed detailed analysis of phenotypic variation in endosperm between two interploidy reciprocal crosses arising from tetraploid (Triticum durum, AABB) and hexaploid wheat (Triticum aestivum, AABBDD). In the paternal‐ versus the maternal‐excess cross, the timing of endosperm cellularization was delayed and starch granule accumulation in the endosperm was repressed, causing reduced germination percentage. The expression profiles of genes involved in nutrient metabolism differed strongly between these endosperm types. Furthermore, expression patterns of parental alleles were dramatically disturbed in interploidy versus intraploidy crosses, leading to increased number of imprinted genes. The endosperm‐specific TaLFL2 showed a paternally imprinted expression pattern in interploidy crosses partially due to allele‐specific DNA methylation. Paternal TaLFL2 binds to and represses a nutrient accumulation regulator TaNAC019, leading to reduced storage protein and starch accumulation during endosperm development in paternal‐excess cross, as confirmed by interploidy crosses between tetraploid wild‐type and clustered regularly interspaced palindromic repeats (CRISPR) – CRISPR‐associated protein 9 generated hexaploid mutants. These findings reveal a contribution of genomic imprinting to paternal‐excess interploidy hybridization barriers during wheat evolution history and explains why experienced breeders preferentially exploit maternal‐excess interploidy crosses in wheat breeding programs.
Ultrasound assessment of the nose vasculature: A review of the common method of non‐surgical filler‐based rhinoplasty
Authors: Shekarriz Pantea , Hosseini Farid , Shojaee Pardis
Published: October 2023

Background

With the increasing use of dermal injectable fillers in aesthetic medicine, the popularity of non‐surgical filler‐based rhinoplasty (NSR) is also growing. While performing this procedure might result in certain vascular complications, injecting deep into the midline of the nose is commonly considered the safest method for blind primary NSR.

Aims

In this study, we challenged the common NSR method with a Doppler ultrasound study of the nose.

Patients/Methods

The vascular pattern of the common zones of the NSR procedure (radix and nasal tip) of 21 Iranian women were investigated by using a 14 MHz Doppler handheld ultrasound device (Silarious L14PS). Participants had never undergone any procedure on their nose. We focused on the depth of midline vessels in the radix and nasal tip. The radix was studied sagittally and horizontally, and the nasal tip was examined axially by ultrasound.

Results

In the radix of eight cases (38%), at least one vessel was observed at midline, and all were superficial. In the nose tip of 18 cases (86%), at least one vessel was observed at midline, and 9 out of these 18 vessels (50%) were deep. As a result, conducting NSR by the common method in our study population was relatively safe in the radix, but there was an increased likelihood of vascular events in the tip.

Conclusion

Our research results show that while the common method of the NSR may carry a high risk of vascular events, the safety of this procedure could be enhanced by using ultrasound for planning and conducting a tailored treatment.
A structural equation modeling analysis of the effects of nurses' spirituality and spiritual care on professional quality of life
Authors: Ocalan Sinem , Bilgin Aylin , Kovanci Mustafa Sabri
Published: October 2023

Spiritual care helps nurses establish a deeper connection with patients and meet their spiritual needs. Spiritual belief is thought to enable nurses to be more effective in their profession and positively affect their quality of life. This study aimed to investigate the effects of nurses' spirituality and spiritual care on quality of life. This study was designed as a descriptive cross‐sectional study using structural equation modeling. A total of 221 nurses were included. Data were collected using the Professional Quality of Life Scale, and Spirituality and Spiritual Care Scale. The data were analyzed using descriptive statistics, correlational statistics, and structural equation modeling. Spirituality and spiritual care were negative predictors of burnout and positive predictors of compassion satisfaction. Spirituality and spiritual care decreased the level of burnout in nurses and significantly increased the level of compassion satisfaction. This study suggests raising nurse awareness of spirituality and spiritual care. Supporting nurses with professional training programs, including spiritual care, may benefit their quality of life.
The OsNLP3/4‐OsRFL module regulates nitrogen‐promoted panicle architecture in rice
Authors: Wu Jie , Sun Liang‐Qi , Song Ying , Bai Yu , Wan Guang‐Yu , Wang Jing‐Xian , Xia Jin‐Qiu , Zhang Zheng‐Yi , Zhang Zi‐Sheng , Zhao Zhong , Xiang Cheng‐Bin
Published: October 2023

Rice panicles, a major component of yield, are regulated by phytohormones and nutrients. How mineral nutrients promote panicle architecture remains largely unknown.

Here, we report that NIN‐LIKE PROTEIN3 and 4 (OsNLP3/4) are crucial positive regulators of rice panicle architecture in response to nitrogen (N). Loss‐of‐function mutants of either OsNLP3 or OsNLP4 produced smaller panicles with reduced primary and secondary branches and fewer grains than wild‐type, whereas their overexpression plants showed the opposite phenotypes.

The OsNLP3/4‐regulated panicle architecture was positively correlated with N availability. OsNLP3/4 directly bind to the promoter of OsRFL and activate its expression to promote inflorescence meristem development. Furthermore, OsRFL activates OsMOC1 expression by binding to its promoter.

Our findings reveal the novel N‐responsive OsNLP3/4‐OsRFL‐OsMOC1 module that integrates N availability to regulate panicle architecture, shedding light on how N nutrient signals regulate panicle architecture and providing candidate targets for the improvement of crop yield.
Role of DNA methylation‐based mitotic ageing indices in oral cancer development and recurrence
Authors: Ambatipudi Srikant , Inchanalkar Mayuri , Mahimkar Manoj B.
Published: October 2023

Objective

DNA methylation data can be used to derive mitotic indices from complex tissues. Here, we assessed if the DNA methylation‐derived mitotic ageing indices are associated with oral squamous cell carcinoma (OSCC) development and recurrence‐free survival (RFS).

Methods

DNA methylation‐based mitotic indices (MitoticAge, TNSC and hypoSC) were derived using algorithms “MitoticAge” and “epiTOC2” for the discovery [non‐malignant (n = 22), premalignant (n = 22) and OSCC (n = 68) tissues] and validation datasets (GSE87053, GSE136704 and TCGA‐HNSCC). Differences in mitotic indices between non‐malignant, premalignant and OSCC tissues were assessed. Finally, the association between estimated mitotic indices and RFS was evaluated in OSCCs.

Results

In the discovery and validation datasets, increased mitotic ageing was observed in OSCC compared to non‐malignant and premalignant oral tissues. HPV‐positive HNSCCs had higher mitotic index TNSC. Mitotic age index hypoSC was associated with RFS in OSCC (p = 0.011, HR 2.61, 95% CI 1.24–5.48).

Conclusions

DNA methylation‐derived mitotic indices are associated with OSCC development and RFS. Thus, DNA methylation‐derived mitotic indices may be a valuable research tool to reliably estimate the cumulative number of stem cell divisions in malignant and non‐malignant oral tissues. Future research utilizing mitotic indices for predicting clinical outcomes in OSCC is warranted.
Environment‐dependent population dynamics emerging from dynamic energy budgets and individual‐scale movement behaviour
Authors: Barhdadi Wissam , Daly Aisling J. , Baetens Jan M. , Baets Bernard De
Published: October 2023

Individual biology influences environment‐dependent population dynamics through life history. Population models that consider individual physiology are therefore popular for modelling dynamics under various environments. In recent years, a quantitative framework integrating metabolic theory (dynamic energy budget theory) into individual‐based models (DEB‐IBMs) has emerged to investigate the link from individual physiology to demography. However, this link shows substantial variation, some of which may be explained by individual behaviours operating in local environments. Current DEB‐IBMs focusing on population modelling do not consider individual‐scale behaviours and instead resort to imposed population‐level relationships. We therefore propose to extend the DEB‐IBM approach to consider the role of individual‐scale behaviour by replacing the functional response – a population‐averaged phenomenological relationship – with individual‐scale foraging mechanisms in a spatially heterogeneous environment. Using this model, we simulate consumer dynamics in a consumer‐resource system for different individual behaviours across a range of temperature, resource carrying capacity and individual variability values. We further illustrate the model in a case study by comparing simulated population dynamics with both the classical DEB‐IBM and experimental data for a laboratory Daphnia magna population. Simulations reveal that temperature‐ and resource‐dependent consumer extinction probability patterns change with individual behaviour. Moreover, simulations agree with experimental data on D. magna populations: dynamics after the initial growth peak were better captured under random walk movement behaviour compared to the classical DEB‐IBM. Both the simulation and case study showed how fine‐scale behaviour mediates the metabolism's impact on population dynamics by allowing for the emergence of different functional responses. Our model thus provides a link between metabolism, life history and population dynamics by centring behavioural mechanisms and environmental heterogeneity at the individual scale. This expansion of the modelling toolbox for physiologically structured populations can boost theory development by bridging various fields in ecology, and contribute to our understanding of environment‐dependent ecological patterns.
Pulmonary vein isolation by means of a novel cryoballoon technology in paroxysmal atrial fibrillation patients: 1‐year outcome from a large Italian multicenter clinical registry
Authors: Bianchi Stefano , De Simone Antonio , Iacopino Saverio , Fassini Gaetano , Malacrida Maurizio , Rossi Pietro , Stabile Giuseppe , Petretta Andrea , Tundo Fabrizio , Cauti Filippo Maria , Iuliano Sara , Filannino Pasquale , Moltrasio Massimo , Morlacchi Bonfanti Michela , Pelargonio Gemma , Pecora Domenico , Ferraro Anna , Tondo Claudio
Published: October 2023

Introduction

Recently, a new cryoballoon (CB) technology (POLARx; Boston Scientific) has come onto the market. Preliminary data have shown that its acute safety and efficacy are similar to those of the first‐generation CB. The aim of this study was to assess the medium‐term outcome of pulmonary vein isolation (PVI) with the POLARxTM CB in a large multicenter registry.

Methods

We prospectively collected data on 125 consecutive patients with paroxysmal atrial fibrillation (AF) who underwent PVI by means of a novel CB system. Two cases of transient phrenic nerve palsy occurred, with full recovery in the 48h post procedure; no major procedure‐related adverse events were reported. During the 90‐day blanking period, 4 (3.2%) patients experienced an early recurrence. After the blanking period, over a mean follow‐up of 411 ± 62 days, 19 patients (15.2%) suffered an AF/atrial tachycardia (AT) recurrence. The 1‐year freedom from AF/AT recurrence was 86.4% (n = 17): 10 (8%) patients had an AF recurrence, 6 (4.8%) had an AT occurrence and 1 (0.8%) suffered both events. Patients with AF/AT recurrences had both a shorter deflation time and total deflation time. Moreover, CB ablations with measured TTI < 90 s and TTI < 60 s were more frequent in patients without AF/AT recurrence (88.5% and 77.4%, respectively) than in those who experienced at least one AF/AT recurrence (67.5% and 55.0%, p = .001 and p = .005, respectively).

Conclusion

The novel POLARx cryo‐balloon system is safe and effective for PV isolation, displaying a 1‐year freedom from atrial arrhythmia recurrence of 86.4%, which is in line to that reported with AFA‐Pro CB or RF ablation.

Clinical trial registration

Catheter Ablation of Arrhythmias with a High‐Density Mapping System in Real‐World Practice (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998. Registration date: January 4, 2019.
Fracking Twitter: Utilizing machine learning and natural language processing tools for identifying coalition and causal narratives
Authors: Pattison Andrew , Cipolli William , Marichal Jose , Cherniakov Christopher
Published: October 2023

The Narrative Policy Framework (NPF) has provided policy scholars with a valuable method to gain empirical insight into the power of narratives in the policy process. However, a significant limitation of the NPF has been its ability to deploy this framework on large N datasets due to the labor‐intensive nature of collecting narrative data. In recent years, NPF scholars have turned to computational social science tools to address this challenge. This study builds upon this emerging body of literature and our previous work, which uses sentiment analysis, a natural language processing technique, to evaluate the use of the angel/devil shift across coalitions before and after a major policy change. We examined Tweets that included the terms “fracking” and “New York” before and after the introduction of a moratorium. While sentiment analysis allowed us to gain insight into the narrative structure of the fracking policy discourse space, the labor involved in hand‐coding Twitter users into neutral‐, pro‐, or anti‐fracking groups was onerous. This project aims to supplement our natural language processing method by employing supervised machine learning techniques to increase the universe of respondents. We hand‐coded 500 Twitter users into neutral‐, pro‐, or anti‐fracking groups and trained a much larger dataset using an extreme gradient boost algorithm to classify a broader corpus of Tweets. This enabled us to expand the number of Tweets used in the analyses. We then applied sentiment analysis on this newly classified larger dataset to reveal differences in the pro‐fracking and anti‐fracking advocacy coalitions. By using machine learning to classify pro and con Tweets, we gained the ability to achieve significantly greater insight into how these two subgroups employed different narrative and linguistic devices in their Twitter discussions about fracking.

Related Articles

Merry, Melissa K. 2022. “Trump's Tweets as Policy Narratives: Constructing the Immigration Issue via Social Media.” Politics & Policy 50(4): 752–72. https://doi.org/10.1111/polp.12487.

Robles, Pedro, and Daniel J. Mallinson. 2023. “Catching Up with AI: Pushing toward a Cohesive Governance Framework.” Politics & Policy 51(3): 355–72. https://doi.org/10.1111/polp.12529.

Shanahan, Elizabeth A., Mark K. McBeth, and Paul L. Hathaway. 2011. “Narrative Policy Framework: The Influence of Media Policy Narratives on Public Opinion.” Politics & Policy 39(3): 373–400. https://doi.org/10.1111/j.1747‐1346.2011.00295.x.
Does money bring aspirations? Evidence from China
Authors: Yu Yue , Liu Chengkui , Wang Hao , Lin Xiaodan
Published: October 2023

Based on a mathematical model and empirical test, this paper explores the incentive of income for aspirations and its channels, forging links between theory and data. Results present evidence that income significantly inspires one's aspirations, and all conclusions still hold after overcoming the interference of potential endogenous issues. In terms of channels, the “aspirations window” (a set of similar perceivable individuals) and “bandwidth load” (the mental space to think, process problems, and come up with solutions) play the mediating role in the stimulation of money; that is, low incomes will make aspirations window narrower and bandwidth load heavier, which is a momentous force behind one's aspirations failure. This paper also enlightens income distribution and the construction of internal motivation mechanisms.
Research progress on intestinal tissue‐resident memory T cells in inflammatory bowel disease
Authors: Chen Ke , Gu Xin , Yang Shufan , Tao Rui , Fan Menglei , Bao Wenyang , Wang Xiaoyun
Published: October 2023

Tissue‐resident memory T (TRM) cells are a recently discovered subpopulation of memory T cells that reside in non‐lymphoid tissues such as the intestine and skin and do not enter the bloodstream. The intestine encounters numerous pathogens daily. Intestinal mucosal immunity requires a balance between immune responses to pathogens and tolerance to food antigens and symbiotic microbiota. Therefore, intestinal TRM cells exhibit unique characteristics. In healthy intestines, TRM cells induce necessary inflammation to strengthen the intestinal barrier and inhibit bacterial translocation. During intestinal infections, TRM cells rapidly eliminate pathogens by proliferating, releasing cytokines, and recruiting other immune cells. Moreover, certain TRM cell subsets may have regulatory functions. The involvement of TRM cells in inflammatory bowel disease (IBD) is increasingly recognized as a critical factor. In IBD, the number of pro‐inflammatory TRM cells increases, whereas the number of regulatory subgroups decreases. Additionally, the classic markers, CD69 and CD103, are not ideal for intestinal TRM cells. Here, we review the phenotype, development, maintenance, and function of intestinal TRM cells, as well as the latest findings in the context of IBD. Further understanding of the function of intestinal TRM cells and distinguishing their subgroups is crucial for developing therapeutic strategies to target these cells.
Role of bacteria and microbial metabolites in immune modulation during early life
Authors: Oldereid Tine Simensen , Jiang Xiaojun , Nordhus Kathrine Sivertsen , Ponzetta Andrea , Bjørnholt Jørgen Vildershøj , Björkström Niklas K. , Melum Espen , Rasmussen Henrik
Published: October 2023

Host–microbiome interplay from birth is essential for immune imprinting and tuning. Live gut microbes and microbial‐derived metabolites regulate the development and modulation of the immune system, but whether microbial metabolites solely are sufficient to induce immune maturation remains unclear. Sterile faecal filtrates (FFT) were generated from murine gut contents. Newborn germ‐free (GF) mice were treated twice daily with FFT (GF‐FFT) or saline (GF‐NaCl) from post‐natal day 5 until 4 weeks of age. A third group of GF neonates were conventionalized by the transfer of caecal microbiota with live gut microbes. Host immune compartments were comprehensively immunophenotyped and systemically analysed in all available immune‐related organs using flow cytometry. Oral FFT was associated with reduced survival among neonates (n = 7/19; 36.8% mortality), while saline treatment was well tolerated (n = 1/17, 5.9% mortality). Four‐week‐old FFT‐treated pups were comparable in body weight to GF‐NaCl, and the major B‐cell, conventional T‐cell and unconventional T‐cell subsets were unchanged from saline‐treated mice. Live bacteria administered during early life induced clear changes in proportions of B cells, T cells and T‐cell subsets in all mucosal tissues and secondary lymphoid organs compared to GF‐FFT, including restoration of intestinal natural killer T (NKT) cells with characteristics similar to conventional pups. Our findings show that oral administration of a FFT made of microbial metabolites, antigens and bacteriophages alone is insufficient to induce normal immune development elicited by the presence of live bacteria. Reduced survival during neonatal FFT treatment suggests a potential bioactive attribute of sterile faecal filtrates.
Maximum likelihood estimator for skew Brownian motion: The convergence rate
Authors: Lejay Antoine , Mazzonetto Sara
Published: October 2023

We give a thorough description of the asymptotic property of the maximum likelihood estimator (MLE) of the skewness parameter of a Skew Brownian Motion (SBM). Thanks to recent results on the Central Limit Theorem of the rate of convergence of estimators for the SBM, we prove a conjecture left open that the MLE has asymptotically a mixed normal distribution involving the local time with a rate of convergence of order . We also give a series expansion of the MLE and study the asymptotic behavior of the score and its derivatives, as well as their variation with the skewness parameter. In particular, we exhibit a specific behavior when the SBM is actually a Brownian motion, and quantify the explosion of the coefficients of the expansion when the skewness parameter is close to or 1.
Geopolitical risks and financial stress in emerging economies
Authors: NguyenHuu Tam , Örsal Deniz Karaman
Published: October 2023

We investigate the impacts of geopolitical risks (GPRs) on financial stress (FS) in major emerging economies from 1985 to 2019. Applying a recently developed panel quantile estimation method, we show that GPRs pose serious risks to the stability of the financial condition in emerging economies. Namely, when FS is already equal to or above average, GPRs intensify this instability to a remarkable degree. Nevertheless, GPRs do not ignite the stress when the financial situation is benign. In emerging economies, foreign exchange markets and, to a lesser extent, the banking industry and the debt market suffer more severe consequences of geopolitical tensions than the stock market. In contrast, advanced economies, represented by the Group of Seven (G7), have witnessed detrimental consequences of GPRs on their stock markets, but negligible effects on other parts of their financial systems.
Clinical presentation and short‐term outcomes of dogs ≥15 kg with extrahepatic portosystemic shunts
Authors: Spies Kate , Ogden Jessica , Sterman Allyson , Davidson Jackie , Scharf Valery , Reyes Bianca , Luther Jill Kristine , Martin Libby , Kudej Raymond , Stockman Tiffany , Gallaher Hayley Maloof‐Jones , Buote Nicole J. , Smith Meghan , Ciepluch Brittany , Amore Riley , Sherman Alec H. , Wallace Mandy L.
Published: October 2023

Objective

To describe demographics, clinical presentation, shunt anatomy, clinical progression, and complications in large dogs ≥15 kg with single extrahepatic portosystemic shunts (EHPSS) treated with or without surgery.

Study Design

Multicenter retrospective (10 university hospitals, one private referral institution).

Animals

Dogs ≥15 kg (n = 63).

Methods

Medical records of dogs ≥15 kg diagnosed with EHPSS between January 01, 2005 and December 31, 2020 were reviewed. Dogs had a minimum follow‐up of 90 days. Signalment, clinical signs, diagnostics, shunt anatomy, treatment interventions, and perioperative complications were assessed.

Results

Median age was 21.9 months (IQR: 9–36.8). The breed most represented was the Golden retriever (17/63 dogs). Portocaval (17/63) and splenocaval (15/63) shunt configurations were most common. Portal vein hypoplasia was noted in 18 imaging reports. Of the surgically treated dogs, 14/45 (35.6%) had short‐term complications, and 3/45 (6.7%) had shunt‐related deaths. Medical management was discontinued in 15/40 and reduced in 9/40 of surviving dogs who had surgical attenuation. All medically managed, nonattenuated dogs (18/18) were maintained on their original shunt‐related medication regimens.

Conclusions

Clinical presentation of dogs ≥15 kg with extrahepatic portosystemic shunts was similar to the more commonly reported small breed dogs. Surgical management of single EHPSS in large dogs ≥15 kg had similar clinical short‐term outcomes as small breed dogs.

Clinical Significance

Clinicians should be aware that large breed dogs with EHPSS share similar characteristics and clinical outcomes to small breed dogs. The significance of the presence of a hypoplastic portal vein warrants further research. Surgical treatment is a viable option for large breed dogs with EHPSS.
Development and characterization of islet‐derived mesenchymal stem cells from clinical grade neonatal porcine cryopreserved islets
Authors: Kikuchi Takeshi , Nishimura Masuhiro , Komori Natsuki , Iizuka Naho , Otoi Takeshige , Matsumoto Shinichi
Published: October 2023

Background

Porcine tissues display a great potential as donor tissues in xenotransplantation, including cell therapy. Cryopreserving clinical grade porcine tissue and using it as a source for establishing therapeutic cells should be advantageous for transportation and scheduled manufacturing of MSCs. Of note, we previously performed encapsulated porcine islet transplantation for the treatment of unstable type 1 diabetes mellitus in the clinical setting. It has been reported that co‐transplantation of islets and Mesenchymal stem cells (MSCs) enhanced efficacy. We assume that co‐transplantation of porcine islets and porcine islet‐derived MSCs could improve the efficacy of clinical islet xenotransplantation.

Methods

MSCs were established from fresh and cryopreserved non‐clinical grade neonatal porcine islets and bone marrow (termed non‐clinical grade npISLET‐MSCs and npBM‐MSCs, respectively), as well as from cryopreserved clinical grade neonatal porcine islets (termed clinical grade npISLET‐MSCs). Subsequently, the cell proliferation rate and diameter, surface marker expression, adipogenesis, osteogenesis, and colony‐forming efficiency of the MSCs were assessed.

Results

Cell proliferation rate and diameter did not differ between clinical grade and non‐clinical grade npISLET‐MSCs. However, non‐clinical grade npBM‐MSCs were significantly shorter and smaller than both npISLET‐MSCs (p < 0.05). MSC markers (CD29, CD44, and CD90) were strongly expressed in clinical grade npISLET‐MSCs and non‐clinical grade npISLET‐MSCs and npBM‐MSCs. The expression of MSC‐negative markers CD31, CD34, and SLA‐DR was low in all MSCs. Clinical grade npISLET‐MSCs derived from adipose and osteoid tissues were positive for Oil Red and alkaline phosphatase staining. The results of colony‐forming assay were not significantly different between clinical grade npISLET‐MSCs and non‐clinical grade npBM‐MSCs.

Conclusion

The method described herein was successful in of developing clinical grade npISLET‐MSCs from cryopreserved islets. Cryopreserved clinical grade porcine islets could be an excellent stable source of MSCs for cell therapy.
Ample bodies and Terracini loci of projective varieties
Authors: Laface Antonio , Massarenti Alex
Published: October 2023

We introduce the notion of ample body of a projective variety and use it to prove emptiness results for Terracini loci and specific identifiability results for toric and homogeneous varieties.
Experimental Investigation on Microsecond Pulsed Plasma Supported Biogas Combustion
Authors: Ghabi Ahlem , Boushaki Toufik , Bocanegra Pablo Escot , Robert Eric
Published: October 2023

This paper evaluates the effect of a microsecond pulsed plasma (MPP) on the stabilization and emission characteristics of non-premixed biogas/air flames with various CO2 contents. The MPP is generated by a unique DC-pulsed power generator providing high voltage (HV) pulses over a wide range of pulse repetition frequencies (PRFs). The burner configuration is made up of two concentric tubes in which a swirler is placed inside the annular part, ensuring the oxidizer's rotation. The central tube delivers the fuel through an injector placed close to the burner exit. Electrical diagnostics, including voltage, were performed. OH* chemiluminescence measurements were done to describe the structure and stability of the flame. Results showed that plasma generated by microsecond HV pulses can improve flame stability. In this regard, the distribution of key active species in the burner was studied via optical emission spectroscopy (OES). The results revealed that the pulsed plasma generates chemically active species such as excited N2*, CH*, OH* molecules, and H* and O* atoms, thereby improving flame stability. The dependence of the emitted species intensities on plasma parameters was investigated in detail. It is demonstrated that MPP can drastically enhance the dynamic flame stability of swirling non-premixed biogas flames, especially at lean operating conditions. In addition, NOx and CO emissions were studied over a wide range of pulse repetition frequencies. It is seen that the pulsed plasma increases NOx emission slightly and significantly reduces CO concentration in the flue gases.
Experimental Investigation of the Effect of Superheated Liquid Fuel Injection on the Combustion Characteristics of Lean Premixed Flames
Authors: Izadi Saeed , Zanger Jan , Baggio Martina , Seliger-Ost Hannah , Kutne Peter , Aigner Manfred
Published: October 2023

The effect of superheated liquid fuel injection on the performance and emissions of a single nozzle combustor was investigated. Combustion of the lean premixed flames was achieved using a combination of jet and swirl as a stabilization method. In a nonreactive setup, the optimum transition temperature of Jet A-1 fuel from liquid to superheated vaporized state was analyzed. In a subsequent reactive setup, a series of tests were conducted with the liquid fuel at low and elevated temperatures. The experiments were conducted at ambient pressure and various air and fuel preheat temperatures, axial swirlers, thermal powers, adiabatic flame temperatures, and flame tube diameters. Concentrations of nitric oxide (NOx) and carbon monoxide (CO) in the flue gas were measured. The operating conditions were systematically selected according to the design of experiments (DOE) method. The results showed that the adiabatic flame temperature caused the most significant change in combustion emissions and the position and shape of the reaction zone, while the superheated fuel injection had only a minor effect because the liquid fuel droplets were largely vaporized before entering the reaction zone through the integration of a swirler and a prefilmer. The use of the axial swirler and prefilmer allowed the combustor to operate in both spray and fully vaporized fuel conditions. As a result, very low emission concentrations of NOx (≈5 ppm) and CO (≈6 ppm) were achieved. The median flame length and height above the burner of the characterized flames showed competitive values of 32 mm and 50 mm, respectively. Lean blowout limits of less than 1500 K were achieved. Two different flame modes were observed during the experiments. By increasing the bulk velocity of the combustor, its hysteresis was resolved, resulting in stable and reliable flames with a wide low-NOx operating range.
Scaling of Lean Aeronautical Gas Turbine Combustors
Authors: Gövert Simon , Gruhlke Pascal , Behrendt Thomas , Janus Bertram
Published: October 2023

A numerical procedure is presented for the scaling of lean aeronautical gas turbine combustors to different thrust classes. The procedure considers multiple operating points and aims for a self-similar flow field with respect to a reference configuration. The developed scaling approach relies on an optimization-based workflow which involves automated geometry and numerical grid generation, unsteady Reynolds-averaged Navier–Stokes (URANS) simulations, and postprocessing of the reacting flow field. Kriging is applied as a metamodel to identify new sets of parameters for combustor geometry generation. A generic lean-burn high-pressure aeronautical combustor has been designed to serve as a first verification test case with reactive flow characteristics comparable to real combustion chambers. The burner geometry is parameterized by 23 free parameters which are altered within the scaling process. The definition of a suitable scaling function is essential for the success of the scaling approach. A scaling function based on pressure loss, axial location of heat release, pilot air split, and the temperature profile at the combustor exit is proposed. The developed procedure is tested and applied for the scaling of an internally-staged lean combustor to a lower thrust class considering multiple operating points simultaneously. In total, 65 different combustor variants have been evaluated by the scaling procedure. Simulations were performed for each of these configurations at takeoff, approach, and idle operating conditions. The final combustor configuration, scaled to a lower thrust class, shows good agreement to the reference configuration in terms of the scaling targets and reasonably resembles the emission indices. Integrating the scaling procedure into the design process of future combustion systems could reduce the required design iterations and thereby contribute to significantly reduced development times and costs.
Model Predictive Control Strategies for Turbine Electrified Energy Management
Authors: Hill Elyse D. , Amthor Aria E. , Soloway Donald I. , Simon Donald L. , Connolly Joseph W.
Published: October 2023

The increasing electrification of aircraft propulsion systems is leading to new control architectures being developed to address integration between electric machines (EMs) and gas-based turbine engines. For hybrid-electric propulsion systems, current conceptual architectures often couple electric machines with the shafts of gas turbine engines and introduce energy storage. Leveraging the electrical power system of hybridized engines, turbine electrified energy management (TEEM) is a recent control approach that improves transient operability in an effort to enable more efficient and lighter weight turbomachinery. This study seeks to expand TEEM's application beyond traditional proportional-integral (PI) control by presenting linear model predictive control (MPC) schemes to execute the TEEM concept. Through constraint selection and cost function design, transient operability goals for TEEM are considered with no external logic or saturation. Unique to the designs are the use of a washout filter, which simplifies transient detection and motor activation logic. The proposed architectures are implemented with both centralized MPC (CMPC) and distributed MPC (DMPC) approaches, and comparisons are drawn to a benchmark PI controller simulated on a nonlinear turbofan engine model at one ground condition and one cruise condition. Performance is evaluated using compressor maps, stall margin performance, and two novel metrics: transient stack usage (TSU) and transient excursion integral (TEI). Results reveal that the linear MPC scheme performs comparably to the baseline controller and can be implemented in at least two distinct configurations with potential for further modifications, thus establishing the groundwork for future investigations.
Influence of Variable Swirl on Emissions in a Non-Premixed Fuel-Flexible Burner at Elevated Ambient Conditions
Authors: Pugh Daniel , Bowen Phil , Navaratne Rukshan , Goktepe Burak , Giles Anthony , Valera Medina Agustin , Morris Steven , Vivoli Robin
Published: October 2023

As alternative fuels are designated for future energy applications, flexible combustor designs require considerable development to ensure stable operation with reduced NOx emissions. A nonpremixed variable swirl burner was used to experimentally appraise changes in NO production pathways, with CH4 NH3 and H2 flames, alongside intermediate fuel blends. Maintaining an equivalent thermal power and flame temperature between fuels, preheated reactants (500 K) were supplied to the burner, with parametric changes made to pressure (1–6 bara) and swirl number (0.8–2.0). NO production was characterized, alongside variations in flame structure and topology, with a correlation demonstrated for exhaust emissions. NO production was shown to be sensitive to combustor pressure, providing an expected increase for CH4 and H2 flames. Emission profiles from both NH3 and H2 flames are shown to be significantly augmented by a change in swirl number. As NH3 fractions were increased in the H2 blend, a decaying trend in NO emissions was observed with an increase in pressure, and as a function of mixture ratio. However, this behavior was markedly augmented by a change in swirl number and suggests that further reductions may be possible at increased pressure. At the low swirl/high pressure condition, the NH3/H2 blend outperformed pure H2, providing lower NO concentrations. Emissions data were normalized using the traditional dry/O2 correction, alongside mass scaled by thermal power, with a comparison provided. The corresponding differences in emission formation pathways were investigated, alongside high-speed OH* chemiluminescence to further elucidate findings.
Magneto-Mechanical Metamaterials: A Perspective
Authors: Sim Jay , Zhao Ruike Renee
Published: October 2023

Magneto-mechanical metamaterials possess unique and tunable properties by adjusting their shape configurations in response to an external magnetic field. Their designs and functionalities are diverse and are utilized in a wide variety of applications, such as highly tunable elastic and electromagnetic wave filters and targeted shape morphing. In this perspective, we examine the general background of magneto-mechanical metamaterials and their diverse applications. The possible future directions in the field are also thoroughly discussed.
Closed-Form Expressions of Shear Correction Factor for Functionally Graded Beams
Authors: Amandeep  , Pathak Anup Kumar , Padhee Srikant Sekhar
Published: October 2023

In this work, closed-form expressions of shear correction factor (SCF) have been derived for beams with functionally graded material (FGM), through variational asymptotic method (VAM). An energy equivalence approach has been adopted between VAM and Timoshenko model, for estimating the SCF. A planar FGM beam has been considered and the calculation for SCF has been carried out. The formulation has been derived in a functional form that permits solutions for a large class of gradation models of FGM. In the limiting case when the material becomes homogeneous the estimated SCF matches exactly with that of the literature, thus validating the solution. A detailed discussion has been carried out on the results and conclusions have been drawn.
Core-shell metallic nanotube arrays for highly sensitive surface-enhanced Raman scattering (SERS) detection
Authors: Chu Jinn P. , Yeh Yi-Jui , Liu Chih-Yu , Yang Yi-Xiang , Altama Alfreda Krisna , Chang Ting-Hao , Chiang Wei-Hung , Yiu Pakman , Tung Kuo-Lun
Published: October 2023

Here, we demonstrate the application of highly ordered, periodic Ag/Au core-shell triangle nanotube arrays as an ultrasensitive and low-cost surface-enhanced Raman scattering (SERS) substrate for the first time. The arrays of core-shell nanotube, with an outer diameter of 1.5 μm, were fabricated using top-down wafer-scale lithography followed by sequential sputter deposition of Ag and Au. The SERS activity of various combinations of core-shell structures was evaluated. It was found that Ag-core nanotubes overlaid with the Au-shell resulted in the highest Raman intensity, where the enhancement factor for R6G as a probe molecule is determined to be 1.38 × 107. Meanwhile, the limit of detections for R6G and ketoprofen analytes was evaluated to be 10−10 and 10−6 M, respectively. Linear correlations between the SERS signal intensities and logarithmical scale of both analytes in different concentrations were also established, ranging 10−4–10−10 and 10−2–10−6 M for R6G and ketoprofen, respectively. The Raman R6G peak intensity mapping suggests our metal nanotube arrays act as effective plasmonic hotspots and, thus, are useful for SERS sensing applications.
Closed-form multiple source direction-of-arrival estimator under reverberant environments
Authors: Hu Yonggang , Wang Wei , Gu Zehong , Mao Tianpeng , Zhu Xuchen , Jin Jiabao
Published: October 2023

Accurate direction-of-arrival (DOA) estimation of multiple sources, simultaneously active in a reverberant environment, remains a challenge, as the multi-path acoustic reflections and overlapped periods dramatically distort the direct-path wave propagation. This article proposes a prominent solution localizing multiple sources in a reverberant environment using closed-form estimates, circumventing any exhaustive search over the two-dimensional directional space. Apart from a low complexity cost, the algorithm has robustness to reverberant, inactive, and overlapped periods and an ease of operation in practice, achieving sufficient accuracy compared to state-of-the-art approaches. Specifically, this algorithm localizes an unknown number of sources through four steps: (i) decomposing the frequency domain signals on a spherical array to the spherical harmonics domain; (ii) extracting the first-order relative harmonic coefficients as the input features; (iii) achieving direct-path dominance detection and localization using closed-form estimation; and (iv) estimating the number of sources and their DOAs based on those pass the direct-path detection. Experimental results, using extensive simulated and real-life recordings, confirm the algorithm with a significantly reduced computational complexity, while preserving competitive localization accuracy as compared to the baseline approaches. Additional tests confirm this low-complexity algorithm even with a potential capacity for online DOA tracking of multiple moving sources.
Drosophila melanogaster
as an organism model for studying cystic fibrosis and its major associated microbial infections
Authors: Touré Hamadoun , Herrmann Jean-Louis , Szuplewski Sébastien , Girard-Misguich Fabienne
Published: October 2023

Cystic fibrosis (CF) is a human genetic disease caused by mutations in the
cystic fibrosis transmembrane conductance regulator
gene that encodes a chloride channel. The most severe clinical manifestation is associated with chronic pulmonary infections by pathogenic and opportunistic microbes.
Drosophila melanogaster
has become the invertebrate model of choice for modeling microbial infections and studying the induced innate immune response. Here, we review its contribution to the understanding of infections with six major pathogens associated with CF (
Staphylococcus aureus
,
Pseudomonas aeruginosa
,
Burkholderia cepacia
,
Mycobacterium abscessus
,
Streptococcus pneumoniae,
and
Aspergillus fumigatus
) together with the perspectives opened by the recent availability of two CF models in this model organism.
Diet-induced obesity and diabetes enhance mortality and reduce vaccine efficacy for SARS-CoV-2
Authors: Johnson Robert M. , Ardanuy Jeremy , Hammond Holly , Logue James , Jackson Lian , Baracco Lauren , McGrath Marisa , Dillen Carly , Patel Nita , Smith Gale , Frieman Matthew
Published: October 2023

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), emerged in Wuhan, China, in December 2019. As of September 2023, there have been over 770 million confirmed cases of COVID-19, including over 6.9 million deaths. Epidemiologic studies have indicated that comorbidities of obesity and diabetes mellitus are associated with increased morbidity and mortality following SARS-CoV-2 infection. We determined how the comorbidities of obesity and diabetes affect morbidity and mortality following SARS-CoV-2 infection in unvaccinated and adjuvanted spike nanoparticle (NVX-CoV2373) vaccinated mice. We find that obese/diabetic mice infected with SARS-CoV-2 have increased morbidity and mortality compared to age-matched normal mice. Mice that were fed a high-fat diet (HFD) and then vaccinated with NVX-CoV2373 produce equivalent neutralizing antibody titers compared to those fed a normal diet (ND). However, the HFD mice have reduced viral clearance early in infection. Analysis of the inflammatory immune response in HFD mice demonstrates a recruitment of neutrophils that was correlated with increased mortality and reduced clearance of the virus. Depletion of neutrophils in diabetic/obese vaccinated mice reduced disease severity and protected mice from lethality. This model recapitulates the increased disease severity associated with obesity and diabetes in humans with COVID-19 and is an important comorbidity to study with increasing obesity and diabetes across the world.

IMPORTANCE

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a wide spectrum of diseases in the human population, from asymptomatic infections to death. It is important to study the host differences that may alter the pathogenesis of this virus. One clinical finding in coronavirus disease 2019 (COVID-19) patients is that people with obesity or diabetes are at increased risk of severe illness from SARS-CoV-2 infection. We used a high-fat diet model in mice to study the effects of obesity and type 2 diabetes on SARS-CoV-2 infection as well as how these comorbidities alter the response to vaccination. We find that diabetic/obese mice have increased disease after SARS-CoV-2 infection and they have slower clearance of the virus. We find that the lungs of these mice have increased neutrophils and that removing these neutrophils protects diabetic/obese mice from disease. This demonstrates why these diseases have increased risk of severe disease and suggests specific interventions upon infection.