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An asymptomatic perforation of gastrointestinal caused by ingestion of foreign body:...
qiang wang
Shujie Cheng

qiang wang

and 7 more

February 01, 2023
A woman presented with intermittent left lower abdominal pain associated with a mass and didn't have any other symptoms. During the operation, a local inflammatory mass was found in left lower quarter of abdominal cavity. There are two bony foreign bodies in it. Postoperative pathology suggested an inflammatory mass.
ANTI-LIPOMA POTENTIAL OF FRESH PALM FRUITS EXTRACT
Uchechukwu Okorie
Henry Chukwuemeka Uro-Chukwu

Uchechukwu Okorie

and 2 more

February 01, 2023
ANTI-LIPOMA POTENTIAL OF FRESH PALM FRUITS EXTRACT 3Okorie Uchechukwu, 1,2Uro-Chukwu Henry Chukwuemeka, 3Eleazu Chinedum Ogbonna 1National Obstetric Fistula Centre, Abakaliki, Ebonyi State, Nigeria 2Institute for Nutrition, Nutraceutical & Public Health Research & Development, Nigeria, 3Department of Biochemistry, Alex-Ekwueme Federal University Ndufu Alike, Abakaliki, Ebonyi State, Nigeria *Corresponding author: uchechukwuc20022yahoo.com Abstract Antilipoma potential of fresh palm fruit extract was observed on three subjects who gave their consents. The individuals involved did topical application of the fresh crude palm fruits oil extract on the spots of the lipoma on their body between two to six months leading to the disappearance of the lipoma. There is no recurrence after two years. Although a follow-up is still on-going for the next five years. Keywords: anti-lipoma, liposuction, palm fruits, lipoma
A quality improvement project evaluating haemostasis techniques during tonsillectomy.
Komal Parmanand
Mihiar Atfeh

Komal Parmanand

and 1 more

February 01, 2023
TitleA quality improvement project evaluating haemostasis techniques during tonsillectomy
Variation in patient presentation and the use of computer tomography in the urgent ca...
Christopher Bell
Justin Chau

Christopher Bell

and 1 more

February 01, 2023
Background A peritonsillar abscess (PTA) is a collection of infectious material within the peritonsillar space, seen most often in teenagers and young adults. The diagnosis of a PTA is reliant on a patient’s history and physical exam; however, CT scans continue to be used. The rationale for imaging in the diagnosis of a PTA may be better understood based on patient presenting symptoms and physical exam findings. Methods A retrospective review of adult patients diagnosed with a peritonsillar abscess in an acute care/emergency setting at a tertiary hospital between January 1 to December 31, 2019, was performed. Patients were arranged into two groups: those who underwent a CT scan versus patients who did not scan as part of their clinical work-up. Patient demographics, and differences in the rate of subjective and objective findings were compared. Results 43 patients were included in the study: 19 in the CT scan group, and 23 in the no-CT scan group. There was no statistically significant difference in the history of previous peritonsillar abscess incidence, patient chief complaint at triage, subjective complaints, or objective physical exam findings. The most common patient reported symptoms in both groups were odynophagia and dysphagia. The most common objective findings in both groups included peritonsillar fullness and erythema, and uvular deviation. Conclusion Patients who underwent a CT scan as part of their work-up for a peritonsillar abscess had no difference in symptoms or physical exam findings when compared to patients who did not have a CT scan.
Frequency-Specific Analysis of Hearing Outcomes after Surgery for Chronic Ear Disease...
TaiQin Wang
Xuxiang Chen

TaiQin Wang

and 4 more

February 01, 2023
Objective To analyze frequency-specific hearing results surgery for chronic ear diseases, in relation to various surgical factors. Study design Retrospective cohort study. Setting Tertiary referral centre. Participants A total of 173 patients with chronic ear diseases who underwent surgical management at our hospital. Main outcome measures Air conduction threshold (AC), bone conduction threshold (BC), and air-bone gap (ABG) were tested at 250, 500, 1000, 2000, and 4000 Hz, respectively. Frequency-specific results were investigate in relation to various surgical factors. Results The radical mastoidectomy group and tympanoplasty group significantly improved in AC changes at every frequency. In the tympanoplasty group, ABG at all frequencies except 4,000 (P =.069) significantly improved. AC improved at low and mid frequencies when ossicular reconstruction was conducted. Different tympanic membrane repair materials showed significant improvement in AC at all frequencies. In all groups, BC data revealed significant improvements at 500, 1000 and 2000 Hz. Conclusions The hearing improved significantly postoperatively in AC and ABG test, mainly at low and mid frequencies. The BC improved significantly at 500-2000Hz.
How to Become An Excellent Cardiovascular Scholar & Researcher?
Chunsong Hu

Chunsong Hu

February 01, 2023
What should be encouraged to develop the scientific competence of scholars and researchers (S&R)? What should a scientific evaluation focus on? These are important topics in medical education. In fact, there are several core competencies that should be encouraged, including learning, research, scientific writing, innovation and translational applications. Scientific evaluation should pay attention to several “hard indicators”, including academic leadership, independence, guidance, diversity, cooperation and innovation. But how to become an excellent cardiovascular S&R, it is necessary to continuously improve the scientific ability and levels, including innovation and publishing academic papers as the first or single author in one of the “345” top international journals. Since these key indicators are vital markers, it is time to develop a new scoring system to better and more rationally evaluate one’s scientific performance. In addition, there is a need for more innovative, value-added courses and hands-on experience to greatly improve their academic level.
Vultures in the southeastern United States ingest more plastic in landscapes with mor...
Hannah Partridge
Sophie Barnett

Hannah Partridge

and 4 more

February 01, 2023
Plastics are found in ecosystems worldwide and can have widespread impacts on organisms and the environment. Cathartid vultures, including the black vulture (Coragyps atratus) and the turkey vulture (Cathartes aura), have adapted to urbanized environments, making frequent use of human-made structures and anthropogenic resources. Thus, urban vultures are likely exposed to more plastic materials than rural vultures, which they intentionally or unintentionally ingest when foraging or loafing. Our objective was to determine the extent and type of plastic ingested by black and turkey vultures in an urban environment by (1) measuring the plastic content of regurgitated pellets collected along an urban-to-rural gradient, and (2) identifying the plastics within pellets. We dissected 1,087 pellets collected at eight vulture congregation sites in the Charlotte Metropolitan Area, USA between January 2021 and July 2022. Sixty percent of pellets contained plastic materials, with an average plastic composition by weight of 2.66 ± 8.76%. Repeated measures linear mixed models of the proportion of pellets that were plastic suggested that black and turkey vultures are ingesting more plastic materials when congregation sites are surrounded by more developed landcover and a greater density of commercial food providers, such as food stores and restaurants, within 20km. Fourier transform infrared (FTIR) spectroscopy of a subset of pellets indicated that the most common types of plastic ingested by vultures were silicone rubber (used in tires and automobile/boat seals) and polyethylene (used in plastic bags and food packages). Future research should investigate the relative importance of plastic sources in vulture diets, vulture behavioral changes associated with plastic ingestion, and the consequences of plastic pollution on species health and urban ecosystem functioning.
NAMPT INHIBITION AND INCREASED NAD-BIOAVAILABILITY ATENUATE LIVER DAMAGE IN CCl4-INDU...
Juan Suarez-Cuenca
Ariel Gutierrez  Buendia

Juan Suarez-Cuenca

and 12 more

February 01, 2023
Background and Purpose: Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme within the NAD+ salvage biosynthetic pathway and also a cytokine modulator with effects on inflammation and fibrogenesis. FK866 (NAMPT inhibitor) has shown anti-inflammatory properties. However, FK866-induced depletion of NAD+ may also impair liver bioenergetic metabolism during Chronic Liver Disease (CLD). The aim of this study was to evaluate the effects of NAMPT inhibition and NAD+ restoration on experimental CLD. Experimental Approach. CCl4-induced liver cirrhosis was established after 6 weeks. Treatment groups (n=5 mice per group) included: 1) vehicle; 2) CCl4 control; 3) Silymarin + CCl4; 4) FK866 + CCl4; and 5) NMN+FK866+CCl4. At the end of the experimental induction and treatments, mice were sacrificed and liver was collected for weight, and paraformaldehyde fixed for histological characteristics of inflammation and fibrosis, as well as NAD+/NADH determination by colorimetric assay. Liver function tests were performed from blood sample. Statistical analysis was performed by T-test. Key Results. NAMPT inhibition resulted in a mild attenuation of histological and biochemical features of the CCl4-induced liver damage. NAD+ restoration, by the concomitant administration of its precursor NMN, resulted in a significant improvement of the histological characteristics; evidenced by a lower inflammatory infiltrate and fibrosis as well as lower levels of bilirubin. NAMPT inhibition and adequate NAD+ restoration were confirmed by a colorimetric assay of NADH and NAD+ and biochemical features were measured by routinary Liver Function Tests. Conclusion and implications. This study shows that NAMPT inhibition concomitant to NAD restoration significantly attenuate experimental liver damage.
G protein-coupled receptor modulation of striatal dopamine transmission: Implications...
Mydirah Littlepage-Saunders
Michael Hochstein

Mydirah Littlepage-Saunders

and 3 more

February 01, 2023
Dopamine transmission in the striatum is a critical mediator of the rewarding and reinforcing effects of commonly misused psychoactive drugs. G protein-coupled receptors (GPCRs) that bind a variety of neuromodulators including dopamine, endocannabinoids, acetylcholine, and endogenous opioid peptides regulate dopamine release by acting on several components of dopaminergic circuitry. Striatal dopamine release can be driven by both somatic action potential firing and local mechanisms that depend on acetylcholine released from striatal cholinergic interneurons. GPCRs that primarily regulate somatic firing of dopamine neurons via direct effects or modulation of synaptic inputs are likely to impact distinct aspects of behavior and psychoactive drug actions compared with GPCRs that primarily regulate local acetylcholine-dependent dopamine release in striatal regions. This review will highlight mechanisms by which GPCRs modulate dopaminergic transmission and the relevance of these findings to psychoactive drugs involved in substance use disorders.
Optimization of YOLOV7's hyper parameters for simultaneous object detection in satell...
Abhimanyu Singh
Manisha Nene J

Abhimanyu Singh

and 1 more

February 01, 2023
Object detection is crucial for computer vision applications that use satellite imagery, such as precision agriculture, urban planning, and military applications.Recognizing objects in satellite images is challenging due to numerous factors, including the sheer number of objects, the variety in their positions, the range in their sizes, the quality of the lighting, and the existence of a dense background.Background complexity, differences in data capture geometry, geography, and illumination, and an abundance of different types of objects all contribute to making automatic detection in satellite images particularly difficult.There have been many advancements in object detection methods over time, including YOLO and its variations, CNN and its offshoots, DETR and its offshoots, and so on; nonetheless, it is still required to test these methods on the requisite data set to determine their true efficacy.Researchers have investigated the idea of autonomously detecting structures, automobiles, and other things to reduce the risk of human error and speed up the procedure.Improvements in deep learning algorithms and hardware systems have allowed us to accurately identify a broader range of objects in ultra-high-resolution satellite imagery.Through parameter adjustment and analysis of results on the Xview dataset, we determine the most effective technique for multiple item detection and compare it to other models.
Hepatocyte nuclear factor 4α multiple isoforms, their functions, and their interactom...
Jehison Herrera-Pulido
Francois-Michel Boisvert

Jehison Herrera-Pulido

and 2 more

February 01, 2023
HNF4α is a master regulator gene belonging to the nuclear receptor superfamily involved in regulating a wide range of critical biological processes in different organs. Structurally, the HNF4A locus is organized with two independent promoters and is subjected to alternative splicing with the production of twelve distinct isoforms. Little is known about the mechanisms each isoform uses to regulate transcription and their biological impact, with some reports addressing these aspects. Proteomic analyses have led to identifying proteins that interact with specific HNF4α isoforms. The identification and validation of these interactions and their role in co-regulating targeted gene expression are essential to understand better the role of this transcription factor in different biological processes and pathologies. This review addresses the historical origin of HNF4α isoforms, some of the main functions of the P1 and P2 isoform subgroups and provide information on the most recent hot topic research on the nature and function of proteins associated with each of the isoforms in some biological contexts.
Evolutionary adaptation to steady or changing environments affects competitive outcom...
Isabell Hochfeld
Jana Hinners

Isabell Hochfeld

and 1 more

February 01, 2023
The interplay of phytoplankton competition and adaptation affects how phytoplankton, and ultimately marine ecosystems, respond to global warming. However, current ecosystem models do not consider both processes simultaneously. To study how the interplay of competition and adaptation affects phytoplankton responses to global warming, we developed an innovative ecosystem model for the Baltic Sea that simulates competition between three functional phytoplankton groups and allows for adaptation to changing temperatures. We found that competition and adaptation influence each other, with the outcome depending on environmental conditions. In a steady environment, competition drives adaptation to individual niches to reduce competition pressure. In a changing environment, adaptation enhances the competition pressure by allowing inferior competitors to mitigate the dominance of pre-adapted superior competitors. Our results demonstrate that by neglecting adaptation, models can overestimate warming-related changes in species dominance. Ecosystem models should include both competition and adaptation to accurately simulate phytoplankton responses to global warming.
Animal movement and plant space-use drive plant diversity-productivity relationships
Georg Albert
Benoit Gauzens

Georg Albert

and 5 more

February 01, 2023
Plant community productivity generally increases with biodiversity, but the strength of this relationship exhibits strong empirical variation. In meta-food-web simulations, we addressed if the spatial overlap in plants' resource access and movement of animals can explain such variability. We found that spatial overlap of plant resource access is a prerequisite for positive diversity-productivity relationships, but causes exploitative competition that can lead to competitive exclusion. Movement of herbivores causes apparent competition among plants, resulting in negative relationships. However, movement of larger top predators integrates sub-food-webs composed of smaller species, offsetting the negative effects of exploitative and apparent competition and leading to strongly positive diversity-productivity relationships. Overall, our results show that spatial overlap of plant resource access and animal movement can greatly alter the strength and sign of such relationships. In particular, the scaling of animal movement effects opens new perspectives for linking landscape processes without effects on biodiversity to productivity patterns.
Armed to the teeth: the underestimated diversity in tooth shape in snakes and its rel...
Marion Segall
Celine Houssin

Marion Segall

and 7 more

February 01, 2023
1. The structure, composition, and shape of teeth have been related to dietary specialization in many vertebrate species, except snakes. Yet, snakes have diverse dietary habits that may impact the shape of their teeth. We hypothesize that prey properties, such as hardness and shape, as well as feeding behavior, such as aquatic or arboreal predation, or holding vigorous prey, impose constraints on the evolution of tooth shape in snakes. 2. We compared the morphology of the dentary teeth of 63 species that cover the phylogenetic and dietary diversity of snakes, using 3D geometric morphometrics and linear measurements. 3. Our results show that prey hardness, foraging substrate and the main mechanical challenge are important drivers of tooth shape, size, and curvature. 4. Overall, long, slender, curved teeth with a thin layer of hard tissue are observed in species that need to maintain a grip on their prey. Short, stout, less curved teeth are associated with species that undergo high or repeated loads. 5. Our study demonstrates the diversity of tooth morphology in snakes and the need to investigate its underlying functional implications to better understand the evolution of teeth in vertebrates.
Influences of surface runoff detachment and sediment transport on insoluble nitrogen...
Dongdong Wang

Dongdong Wang

February 01, 2023
A lack of research on sediment displacement has led to a corresponding lack of understanding regarding the movement of insoluble N and P. In this study, we used field simulated rainfall experiments and discovered the following: first, the regulatory effects of the two planting methods on the runoff detachment rate was greater than that on the runoff sediment transport rate, and the influence of rainfall intensity was greater than that of slope. Outside the threshold, the regulatory effects of the two planting methods on runoff detachment and sediment transport on different slope gradients were diametrically opposed. Second, N loss was 10 times higher than P loss during rainfall events. N and P losses were highest on bare slopes, and lowest on slopes on which the Prunella vulgaris combined with earthworms planting method was used. N and P loss during rainfall events increased as rainfall intensity increased, and decreased as slope increased. The rate of change increased under high rainfall intensity or slope gradient. Third, regulation of insoluble N loss under the P. vulgaris-only planting method was achieved through regulation of runoff detachment and sediment transport, with contribution rates of 23.89% and 31.98%, respectively. Regulation of insoluble N loss under the P.vulgaris combined with earthworms planting method was achieved by regulating runoff detachment, with a contribution rate of 66.92%. Regulation of insoluble P loss under the two planting methods was achieved by regulating both the runoff detachment and sediment transport rates.
Performance of a New Family of Modular, Bed-Supported, Chromatography Devices
Gerald Platteau
Guido Stroehlein

Gerald Platteau

and 3 more

February 01, 2023
Pre-packed chromatography columns and cassette filtration units offer many advantages in bioprocessing. These include reduced labor costs and processing times, ease of storage, and enhanced process flexibility. Rectangular formats are particularly attractive as they can be stacked and multiplexed together for continuous processing. Cylindrical chromatography beds have historically been favored even though their bed support and pressure-flow performance vary with bed dimensions. This work presents the performance of rectangular chromatography devices with novel internally supported beds. They are compatible with existing chromatography workstations and can be packed with any standard commercial resin. The devices offer pressure-flow characteristics independent of container-volume, simple multiplexing, and separation performance comparable to cylindrical columns. Their internal bed support allows mechanically less-rigid resins to be used at up to 4 times higher maximal linear velocities, and productivities approaching 200 g/L/h for affinity resins, compared to the 20 g/L/h typical of many column-based devices. Three 5 L devices should allow processing of up to 3 kg of monoclonal antibody per hour.
Optimization of expression host for Thermomyces Lanuginosus lipase
Surabhi Soni
Arvind Lali

Surabhi Soni

and 2 more

February 02, 2023
In today’s bio-based industry, lipase-catalyzed processes hold eminent commercial worth, yet their use is restricted owing to low yields, high production cost, inconsistent reproducibility, and poor performance in native form. Cloning and expression of multiple lipase genes in various systems have been investigated in order to produce enzymes for the food and detergent industries more cheaply since the development of recombinant DNA technology. The identification of novel lipases is still hampered by the rather difficult expression of these enzymes. The expression of lipases still requires a case-to case optimization. However, the unbiased choice of the appropriate promoter system and host for a specific protein of interest remains difficult. Here, we concisely expressed TLIP (Lipase from Thermomyces lanuginosus; mainly used in the detergent industry) in the frequently used conventional and alternative host systems, with their unique features, along with different promoters (T5, T7, aprE and hp4d) to produce recombinant products. Screening of expression was done among both prokaryotic ( Escherichia coli, Bacillus subtilis) and eukaryotic ( Yarrowia lipolytica) hosts consisting of both intracellular and secretory expression. E. coli (BL21 Shuffle) and Y. lipolytica (extracellular) were found to be the best expression systems for lipase production.
Statistical approach for lipase production from thermotolerant Bacillus subtilis TTP-...
Manpreet Kaur
Reena  Gupta

Manpreet Kaur

and 1 more

February 01, 2023
In present study, response surface methodology was employed for the optimization of production of extracellular lipase from thermotolerant Bacillus subtilis TTP-06 which was isolated from Tattapani hot spring of Himachal Pradesh, India. In Plackett-Burman Design (PBD), interactions among six different factors viz. glucose and peptone concentration; pH, temperature, incubation time and olive oil concentration were studied. The factors which showed a positive effect on the production included glucose and nitrogen concentration; pH and temperature. The optimum values of all these positive factors were determined by using Central Composite Design (CCD). Results of statistical analysis of variance (ANOVA) indicated a p-value of <0.05 which revealed the significance of quadratic model with determination coefficient (R2) value of 0.7846. The optimum concentration of glucose 2.75% (w/v) and peptone 1.65% (w/v) in a medium of pH 7.5 incubated at temperature 55ºC for 24 hrs with 1% (v/v) inoculum gave maximum lipase activity of 8.889 U/ml.
Understanding K. phaffii ( Pichia pastoris ) Host Cell Proteins: Proteomic Analysis a...
Sobhana A Sripada
Driss Elhanafi

Sobhana Alekhya Sripada

and 6 more

February 01, 2023
K. phaffii is a versatile expression system that is increasingly utilized to produce biological therapeutics – including enzymes, engineered antibodies, and gene-editing tools – that feature multiple subunits and complex post-translational modifications. Two major roadblocks limit the adoption of K. phaffii in industrial biomanufacturing: its proteome, while known, has not been linked to downstream process operations and detailed knowledge is missing on problematic host cell proteins (HCPs) that endanger patient safety or product stability; furthermore, the purification toolbox has not evolved beyond the capture of monospecific antibodies, and few solutions are available for engineered antibody fragments and other protein therapeutics. To unlock the potential of yeast-based biopharmaceutical manufacturing, this study presents (i) a secretome survey of K. phaffii cell culture harvests that highlights HCPs with predicted immunogenicity, ability to cause product instability by proteolysis or degradation of excipients, and potential to interfere with purification operations via product association or co-elution; and (ii) a novel affinity adsorbent functionalized with peptide ligands that target the whole spectrum of K. phaffii HCPs – PichiaGuard – designed for the enrichment of therapeutic proteins in flow-through mode. The PichiaGuard adsorbent features high HCP binding capacity (~25 g per liter of resin) and successfully purified a monoclonal antibody and an ScFv fragment from clarified K. phaffii harvests, affording up to 80% product yield, and a >300-fold removal of HCPs. Notably, PichiaGuard outperformed commercial ion exchange and mixed-mode resins in removing high-risk HCPs – including aspartic proteases, ribosomal subunits, and other peptidases – thus demonstrating its value in modern biopharmaceutical processing.
Pneumocystis jirovecii pneumonia complicated a case of SARS-CoV-2 infection and multi...
Mahmoud Sadeghi-Haddad-Zavareh
Hamed  Mehdinezhad

Mahmoud Sadeghi Haddad Zavareh

and 4 more

February 01, 2023
Immunodeficient patients are less prone to develop serious complications of COVID-19 and cytokine storm. However, they are more likely to develop opportunistic infections that can mimic the symptoms of the SARS-CoV-2. we presented a 27-year-old male case of SARS-CoV-2, who was complicated with Pneumocystis jirovecii pneumonia, following treatment with rituximab.
Digestive Tract Cancer Related Adverse Events Associated with Proton Pump Inhibitors...
guorong Fan
Sheng-ying Gu

guorong Fan

and 7 more

February 01, 2023
Background Proton pump inhibitors (PPIs) are widely used to treat digestive system diseases. Previous studies have suggested conflicting results between PPIs treatment and digestive tract cancers (DTCs). We utilized the FDA Adverse Event Reporting System (FAERS) database to assess the effect of PPIs use on DTCs through data mining. Method This study examined the association between six PPI agents and DTCs by mining the FAERS database from January 2004 to September 2021 by using Open Vigil 2.1. The reporting odds ratio (ROR) with 95% confidence intervals (CIs) was used to detect statistically significant associations between PPIs and DTCs. High Level Terms (HLTs) and Preferred Terms (PTs) were defined by the Medical Dictionary for Regulatory Activities 24.0 (MedDRA24.0). Result A total of 2553 DTCs adverse event reports were screened, with positive signals obtained from gastric neoplasms malignant (GNM) (ROR: 1.09, 95% CI: 1.01-1.18) and bile duct neoplasms malignant (BDNM) (ROR: 1.80, 95% CI: 1.44-2.25). Esomeprazole showed the strongest signal (ROR: 1.85, 95% CI: 1.66-2.06) for GNM, while rabeprazole for BDNM (ROR: 2.94, 95% CI: 1.32-6.56), and female PPI users had a higher risk of BDNM (ROR: 2.44, 95% CI: 1.77-3.35). Among Subordinate PTs, adenocarcinoma gastric, and the combination of “bile duct cancer” and “cholangiocarcinoma” were highly associated with PPIs use. Conclusion By mining the FAERS database, we provided important clues for the association between PPIs use and DTCs risk.
Study on optimal dispatching of clean energy heating considering customer satisfactio...
Haifeng Chen
Houjing Guo

Haifeng Chen

and 6 more

February 01, 2023
Abstract: The consumption of coal in winter heating period in northern China is large, and the combustion generates greenhouse gases that pollute the environment. At the same time, wind abandonment is widespread in northern China, causing waste of energy. In order to solve these problems, this paper proposes to apply clean energy heating and waste wind power generation for heating, and build a multi-objective optimal dispatching model under the goal of considering Customer satisfaction and operating costs. Finally, taking a region in the north of China as an example, the improved genetic algorithm is used to solve the model. The example results verify that the use of clean energy heating can increase the wind power consumption space and reduce the heating cost in winter.
Design of gas turbine combustors for the reduction of nitrogen oxides emissions by he...
Junjie Chen

Junjie Chen

February 06, 2023
Flammable mixtures of most fuels are normally burned at relatively high temperatures, which inherently results in the formation of substantial emissions of nitrogen oxides. In the case of gas turbine combustors, the formation of nitrogen oxides can be greatly reduced by limiting the residence time of the combustion products in the combustion zone. However, even under these circumstances, undesirable quantities of nitrogen oxides are nevertheless produced. Additionally, limiting such residence time makes it difficult to maintain stable combustion even after ignition. The present study relates to the design of gas turbine combustors for the reduction of nitrogen oxides emissions by heterogeneous catalysis. Steady-steady simulations are performed using computational fluid dynamics. The fluid viscosity, specific heat, and thermal conductivity are calculated from a mass fraction weighted average of species properties, and the specific heat of each species is calculated using a piecewise polynomial fit of temperature. Natural parameter continuation is performed by moving from one stationary solution to another. Particular emphasis is placed upon the sustained combustion of at least a portion of fuel under essentially adiabatic conditions at a rate which surmounts the mass transfer limitation. The results indicate that it is possible to achieve essentially adiabatic combustion in the presence of a catalyst at a reaction rate many times greater than the mass transfer limited rate. Flammable mixtures of carbonaceous fuels normally burn at relatively high temperatures, and substantial amounts of nitrogen oxides inevitably form if nitrogen is present. Complete catalytic combustion of a target species can only occur when oxygen gas is found in molar stoichiometric excess; a condition which is easily met when the target species is present in trace quantity in air. In combustion systems utilizing a catalyst, there is little or no nitrogen oxides formed in a system which burns the fuel at relatively low temperatures. In the mass transfer limited zone, the reaction rate cannot be increased by increasing the activity of the catalyst because catalytic activity is not determinative of the reaction rate. Among the unique advantages of the catalytically supported thermal combustion in the presence of a catalyst is the fact that mixtures of fuel and air which are too fuel-lean for ordinary thermal combustion can be burned efficiently.Keywords: Heterogeneous catalysis; Nitrogen oxides; Gas turbines; Flammable mixtures; Thermodynamic properties; Combustion phenomena
Construction of Dynamic Alloy Interface for Uniform Li Deposition in Li-Metal Batteri...
Guang He
Qingwen Li

Guang He

and 5 more

February 01, 2023
It is well accepted that a lithiophilic interface can effectively regulate Li deposition behaviors, but the influence of the lithiophilic interface is gradually diminished upon continuous Li deposition that completely isolates Li from the lithiophilic metals. Herein, we perform in-depth studies on the creation of dynamic alloy interface upon Li deposition, arising from the exceptionally high diffusion coefficient of Hg in the amalgam solid solution. As a comparison, other metals such as Au, Ag and Zn have typical diffusion coefficients of 10-20 orders of magnitude lower than for Hg in the similar solid solution phases. This difference induced compact Li deposition pattern with an amalgam substrate even with a high areal capacity of 55 mAh cm-2. This finding provides new insight into the rational design of Li anode substrate for the stable cycling of Li metal batteries.
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