bluuebunny/crossref_metadata_2025 huggingface dataset:
A Matrix-Based Approach to Unified Synthesis of Planar Four-Bar Mechanisms for Motion Generation With Position, Velocity, and Acceleration Constraints
Authors: Deng Xueting , Purwar Anurag
Published: September 2024

This paper introduces a novel matrix-based approach for the simultaneous type and dimensional synthesis of planar four-bar linkage mechanisms, accommodating various practical constraints, including position, velocity, acceleration, and joint placements. Traditional design processes segregate type synthesis, the determination of joint and link configurations, from dimensional synthesis, which involves specifying link sizes and pivot locations. This segregation often leads to complexities in addressing the complete design challenge. The novel methodology proposed in this paper departs from the conventional sequential design approach by concurrently evaluating type and dimensional parameters using a data-driven matrix formulation. The crux of the paper’s methodology involves formulating a singular design equation through a transformation matrix, parameterized by the Cartesian parameters of the mechanism’s dyads. This formulation linearly expresses a broad range of constraints, facilitating the identification of viable solutions through singular value decomposition and null space analysis. This integrated approach not only simplifies the synthesis process but also provides direct insights into the mechanism’s parameters, encompassing both type and dimensions, thereby obviating the need for further interpretative steps common to the use of quaternions and kinematic mapping. In essence, the paper presents two main contributions: the development of a unified design equation capable of encompassing a wide array of constraints within the mechanism synthesis process, and the introduction of an algorithm that effectively identifies all potential planar four-bar linkage mechanisms by accurately satisfying up to five constraints. This approach promises to enhance the design and optimization of mechanical systems by offering a more holistic and efficient pathway to mechanism synthesis.
Femtosecond Pulsed Laser Machining of Fused Silica for Micro-Cavities With Sharp Corners
Authors: Brinkmann Moritz , Qian Yongfeng , Huang Hu , Yan Jiwang
Published: September 2024

Fused silica is an important material for applications requiring high temperature resistance, low thermal expansion coefficient, and excellent optical properties. The machining of micro-cavities on fused silica surfaces is of particular interest for micro-fluidic manipulation and miniaturization of high-quality optical waveguides, etc., but it still remains technically challenging for traditional manufacturing techniques. In the present study, machining of square cornered semienclosed micro-cavities on fused silica surfaces by femtosecond laser has been investigated experimentally. The effects of laser machining conditions including laser power, laser scanning speed, laser incidence angle, and laser-off delay time on the sidewall slope and bottom surface roughness of the micro-cavities were comprehensively investigated. The results indicated that laser power played an important role in determining the sidewall slope of the micro-cavity, while the laser scanning speed had a significant influence on the bottom surface roughness and subsurface damage. Furthermore, the sidewall slope of the micro-cavity was linearly increased as the laser incidence angle increases. By using a laser incidence angle of 10 deg and a laser-off delay time of 280 ms, a micro-cavity with sidewall slopes close to right angles (90 deg) was fabricated. This study demonstrates that femtosecond laser machining is an effective method for fabricating sharp cornered micro-cavities in fused silica, and the appropriate selection of laser machining conditions based on practical application scenarios is important.
Design of Solar Powered Desalination System and Applications in a Luxurious Beach Resort
Authors: Khuri Siren , Ghaith Fadi A.
Published: September 2024

The efficacy of seawater desalination has a profound impact in terms of reducing the water demand-supply gap especially in dry and arid countries. In UAE, 90% of the country’s water supply relies solely on desalinated water where a high share of the desalination plant’s output is aimed towards water supply for residential buildings. The hospitality sector consumes 50% more than the global average. The purpose of this paper is to determine the technical and economic viability for the integration of a concentrated photovoltaic thermal (CPV/T) system with a hybrid reverse osmosis (RO) and multi effect desalination (MED) plant. The system was designed to meet the water demand of a luxurious beach resort located in Fujairah. The resort accommodates about 110 occupancies per day. The estimated water consumption is 51m3/hr. The proposed system was analyzed with the aid of numerical simulation and reverse engineering calculations. The capacity of the CPV/T module, which represents the electrical and thermal energy output supplied to the RO and MED plant was determined using TRNSYS software. The results showed an efficient solar system providing electricity of 3500 kWh/year and thermal energy of 14,100 kWh/year, that is required to meet the water consumption of the hotel. In addition, the proposed system proved to be economically feasible, achieving a payback period of 3.6 years under an average lifetime of 20 years.
Network Optimization for Sustainable Integration of Decentralized Biogas Production
Authors: Huber David , Birkelbach Felix , Hofmann René
Published: September 2024

Facing the urgent need to mitigate anthropogenic climate change, reducing emissions from the combustion of natural gas has become imperative. This is particularly challenging in the steel or cement industry, where high-temperature heat is essential. A promising solution is substituting natural gas with biogas or hydrogen. The typically highly decentralized gas production presents a transportation challenge due to the high costs of pipeline networks. In this paper, we propose a novel Mixed Integer Linear Programming (MILP) formulation to minimize the investment costs of pipeline networks. The pipeline network is modeled dendritically, allowing the efficient connection of multiple production plants and feed points. The topology of the network and the discrete pipe diameters are optimized simultaneously. A significant novelty is the use of a boolean matrix-vector multiplication in our formulation, allowing the usually non-linear formulation to be formulated linearly without loss of information. This enables hitherto unsolvable problems to be solved using highly efficient MILP solvers. The method is demonstrated using a case study with 37 biogas plants and seven feed points in Austria. The optimization results are the topology of the network and the pipe diameters at minimum specific costs of 3.24 €/(MW h). The results further highlight the economic efficiency of individual clusters, enabling decision-makers to implement step-by-step network expansion. The proposed method represents a novel contribution to optimizing the construction of gas transport infrastructure for biogas, offering potential applications in the broader context of renewable energy integration.
Improved Performance of Transcritical R744 Gas Coolers For Efficient Heat Pumps in the Northeastern US Winter Markets
Authors: Garraway David , Rob S. M. Abdur , Turbeville Geoffrey , Chussid Samuel , Ramamurthy Prathap , Gonzalez-Cruz Jorge E.
Published: September 2024

The main goal of our effort is to analyze, design, develop prototype and test electrical air source heat pumps (ASHPs) for hot water, space heating and cooling for multi-family buildings. Focusing on implementing the use of low Global Warming Potential refrigerants (e.g. TR-CO2) system to provide a cleaner and more sustainable alternative to society’s heating and cooling needs. This specific research is focused on the heating mode. A key challenge of TR-CO2 systems is the heat rejection which occurs in the gas cooler as a single gas phase. Identification of the pinch point is essential to avoid occurring within the gas cooler; leading to increases in efficiency.

We present here system performance of a TR-CO2 air source heat pump system using a customized python computer model coupled to commercial software for whole building analysis. This coupling enables variable heating load conditions for a mid-size multi-family building in New York City. The heat pump system is being modeled using proprietary code for the heat pump system coupled to EnergyPlus™ software with different gas cooler variations for constant and then variable loads. The TR-CO2 system is benchmarked against R410A with very optimistic results.
Nontechnical Barriers to Building Decarbonization in the U.S.
Authors: Osterwood Kristen , Monat Jamie
Published: September 2024

The need to reduce anthropogenic carbon emissions into the atmosphere is abundantly clear. It is also becoming widely accepted that transitioning to air source heat pumps (ASHP) is an essential part of the solution to decarbonizing buildings. The technological barriers to such a transition are covered in the literature, but the nontechnical barriers of adoption of ASHP also need to be considered. The technical focus of the decarbonization problem has blossomed into complex models as an increasing number of factors are incorporated, yielding more accurate models. Although some challenges to ASHPs are mentioned, research into the barriers and evaluation of methods to overcome those barriers are essential to successfully reduce anthropogenic carbon. Technical barriers pair with technical solutions — but nontechnical barriers are often slightly ambiguous and messy and the corresponding solutions require input from other disciplines.

This research identifies the nontechnical challenges of heat pump adoption and potential solutions. First, we present a review of existing models to demonstrate the growing consensus that ASHP are an essential part of decarbonization. Second, we present the nontechnical barriers as covered in the literature and compare those with the discovered nontechnical challenges through a case study and firsthand accounts. We find that the theoretical ideas of nontechnical barriers do not all align with the barriers in reality, and that these, especially the perception of the ineffectiveness of ASHP, needs to be addressed to enable the level of adoption necessary to meet climate goals.

Of the many challenges, from training to financial, the hurdle that is most pervasive, and potentially the most challenging to overcome is, perception of the ineffectiveness of heat pumps at cold temperatures. The perception of the inability of ASHP to function in cold weather is held by those from all levels of education — from the average consumer to those doing academic research on the topic. The persistence of this misunderstanding impacts incentive programs, decreases consumer confidence in the technology, installer recommendations, and increases the overall cost to transition, as a backup source of heat is recommended. Other misunderstandings and non-technical obstacles also must be identified and addressed. Only by clearly identifying the real-world challenges to adoption, potential solutions, and evaluating the effectiveness of strategies to support ASHP adoption, can the United States reach the level of ASHP penetration necessary to achieve climate goals.
Optical Analysis and Optimization of a New Receiver for Solar Parabolic Trough Collectors (DETECTIVE)
Authors: Ebadi Hossein , Alarcón-Padilla Diego-César , Contreras Keegan Juan José , Guedez Mata Rafael Eduardo , Trevisan Silvia , Valenzuela Gutiérrez Loreto , Zarza Moya Eduardo , Savoldi Laura
Published: September 2024

DETECTIVE (Development of a novEl Tube-bundlE-CaviTy lInear receiVEr for CSP applications) is a project that aims at enhancing the overall performance of the current solar parabolic trough collectors. The proposed design focuses on improving such performance by substituting the traditional single metal absorber tube with a tubular bundle whose outer contour largely matches the outer circumference of the replaced tube. To assess the optical performance of the proposed receiver, a Monte Carlo ray tracing technique was employed by utilizing the SolTrace software. The effects of the two design parameters, such as cavity opening angle and cavity radius, on the overall optical behavior have been explored and the optimum design is determined with the maximum optical performance. The ray tracing data proved that the cavity-like space formed within the multi-tube arrangement results in a multi-reflection process between bundle tubes and could result in a higher ray absorption compared to the conventional design, leading to lower optical losses. The obtained numerical results indicated that an aperture angle of 60° could provide the highest optical performance among the studied options. Considering the second parameter, the rise in the cavity radius is shown to increase the ray intersection inside the cavity, while the optical efficiency decreases. Finally, the most efficient design reaches an enhancement of 10% in optical efficiency if compared to the conventional PTC design.
From Waste to Resource: A Techno-Economic Evaluation of a CO2 Heat Pump and ORC Combined System With Photovoltaic Integration and Thermal Storage
Authors: Liaqat Kashif , Soleimani Shima , Leibowitz Sophie , Temming Jörg , Kösters Heiner , Schaefer Laura
Published: September 2024

The escalating global energy demand has resulted in a corresponding increase in greenhouse gas emissions. Multiple energy sources of various quality levels and forms must be developed to reduce emissions. One promising approach involves utilizing low-grade heat sources such as industrial process heat. This work investigates a novel combined heating and power approach through a comprehensive techno-economic analysis of a hybrid system that combines a CO2 heat pump (HP) and an organic Rankine cycle (ORC) for utilizing low-grade waste heat. The HP is powered by photovoltaics (PV), enabling sustainable heat extraction from low-grade sources, and is further integrated with thermal energy storage (TES) for demand management. The system primarily aims to supply district heating, but it seamlessly transitions to an ORC-based power generation mode in scenarios with reduced district heating demand. The integration of PV, HP, ORC, and TES allows for the efficient utilization of diverse low-grade heat sources, with adaptability to various operational strategies and applications contingent upon demand and supply dynamics. The study’s techno-economic and parametric analysis explores component and system-level performance, with Miami, FL, serving as a case study. Lastly, multiple operational scenarios and trade-offs are presented based on heating demand, power generation requirement, and resource availability.
Numerical and Experimental Investigation of the Wind Influence on Scaled-Up Open Volumetric Cavity Receivers
Authors: Drexelius Maximilian , Schwarzbözl Peter
Published: September 2024

Solar tower power plants have the potential to become a valuable asset in renewable electricity and heat generation. Among the available receiver technologies, the open volumetric air receiver (OVR) offers a high level of technical readiness, robustness and the potential for high temperature applications with effective storage capabilities. Tests at the Solar Tower in Jülich have demonstrated the availability and promising receiver efficiencies at the level of a 1.5 MWe demonstration plant. Ongoing research projects at DLR are investigating the potential of the OVR in a scaled-up tower concept. The proposed design uses a multi-receiver concept where the receivers are arranged in cavities to further increase the receiver efficiency. A scale-up to 50 MWe is realized with tower heights of around 200 m, which increases the relevance of ambient wind. Compared to closed-loop surface receivers, the OVR is particularly sensitive to fluctuations in ambient conditions due to the open process design. To investigate the wind influence on cavity OVRs, the surface pressure distribution was analyzed in wind tunnel experiments under a range of wind conditions with Reynolds numbers up to 13.17E06. In addition, numerical simulations based on RANS and DES approaches were performed to further investigate the interaction between the receiver flow and the ambient wind. The CFD model was successfully validated against the experimental results and surface pressure fluctuations could be quantified for the expected wind conditions. Furthermore, the wind influence on the air return ratio and receiver efficiency of the cavity design is numerically evaluated for different wind speeds. In addition to that, counter-measures regarding the return air distribution are numerically evaluated to increase the receiver efficiency.
Evaluating Reduced Order Models for Training Reinforcement Learning Agents for Building HVAC Control
Authors: Kerr Matthew , Howard Bianca
Published: September 2024

Reinforcement learning (RL) for controlling building heating, ventilation, and air conditioning (HVAC) systems has shown promise in delivering energy-efficient, energy-flexible and resilient buildings. However, training RL agents in real-time in buildings is generally considered time and cost prohibitive. RL agents can be trained offline in simulated environments, reducing the time to performance once online, but complex models for simulation can be difficult to generate. What level of complexity is required in an offline training model to produce acceptable online results is unknown. This work seeks to determine how simplified models can be used to train RL agents for building HVAC control. The work uses the EnergyPlus simulation environment paired with HVAC systems modeled in Modelica to act as the real-world analogue environment. Simplified reduced-order models of the building were developed using the lumped capacitance method. The results show that an RL agent trained using Deep Q Learning on a simplified building model can be transferable to a more complex building simulation environment with comparable performance. In virtually all cases, the RL agents were able to deliver improved performance over the baseline proportional controller. Online learning gave mixed results in terms of enhancing the policy transfer process. The implementation in this paper was more suitable for improving the performance of poor policy transfer rather than fine-tuning already well-performing policies.
Modeling of Small-Scale Hybrid Biogas Renewable Energy Facility
Authors: Salcido Ryan D. , Lockwood George W. , Rebullar Cedric I. , Anderson Kevin R. , Shafahi Maryam
Published: September 2024

In this study, a Khadi and Village Industries Commission (KVIC) biogas plant was designed to provide thermal energy input into an internal combustion engine. Additionally, a photovoltaic (PV) system was designed to supply energy for electric resistance heating in the biogas digester to maintain optimal temperatures for manure to decompose in. A MATHCAD based thermal model was built to predict the performance of the biogas plant. The methane gas weekly output by volume of 0.372 cubic meters from the KVIC digester was used to fuel an ACME AM-1500BG 1KW Biogas Generator. This resulted in 1.06 kWh energy output per week when storing biogas over the course of seven days and using the generator at the end of the seventh day. The total annual energy output of the KVIC plant was 55.2 kWh. Thermo-economic modeling of the PV system used carried out using National Renewable Energy Laboratory (NREL) System Advisor Model (SAM). The system nameplate capacity was calculated to be 6.30 kW with an annual AC energy output of 11,735 kWh, resulting in a Levelized Cost of Energy (LCOE) of 11.7¢/kWh and payback period of 9.6 years. The initial investment of the system is $19,261.
Techno-Economic Feasibility Analysis of Solar Industrial Process Heat Using Particle Thermal Energy Storage
Authors: Al-Ghussain Loiy , Johnson Taylor , Martinek Janna , Ma Zhiwen
Published: September 2024

U.S. industry sectors accounted for 33% of total energy consumption in 2021 according to the Energy Information Agency. Industrial process heat accounts for 70% of the industry energy use with application temperatures ranging from 60°–1100°C. Industrial processes heavily rely on fossil fuels including cheap coal or natural gas and differ widely in operating conditions and load requirements which makes them difficult to standardize and imposes challenges in decarbonization. To this end, we have developed a particle-based thermal energy storage (TES) technology integrated with renewable energy sources from concentrating solar thermal power (CST) and/or photovoltaic (PV) power. The particle TES system uses low-cost and highly stable silica sand and can provide industrial process heat (IPH) over a wide range of temperatures. The TES system can serve as a uniform energy supply configuration integrated with renewable power to supply 24/7 heat for industry decarbonization. This paper focuses on the Levelized Cost of Heat (LCOH) and investigated the sensitivity of the LCOH to various economic parameters including the capital costs of the particle-TES system and solar tower system. This paper shows the economic potentials of the particle-TES for IPH applications. Various scenarios of combined on-site CST, PV, electric heater, and TES system capacities were considered to determine configurations of the CSP/PV/TES system that could fulfill the heat demand with minor contributions from grid backup. Conditions necessary to approach an LCOH target of ∼$0.02/kWht were evaluated.
Assessing the Environmental Impacts of Electrified Cement Production
Authors: Nurdiawati Anissa , Terán-Cuadrado Glenda , Al-Ghamdi Sami G.
Published: September 2024

The production of ordinary Portland cement (OPC) is responsible for approximately 5–7% of global anthropogenic carbon dioxide (CO2) emissions. As demand for cement is expected to rise due to increased urban and energy infrastructure projects, it is crucial to transform this sector sustainably to meet these needs while minimizing its significant contribution to environmental impacts. Electrification of heat supply is one of the interesting options for mitigating the generation of CO2 emissions resulting from the combustion of conventional fossil fuels. This study analyzes the cradle-to-gate environmental impacts of a cement plant enhanced with an electrified pre-calciner and plasma gas for high-temperature heat in the rotary kiln, integrated with CO2 capture. This assessment is performed using a life cycle assessment (LCA) and is compared against a reference cement plant. Different scenarios regarding fuels and the effect of using future decarbonization scenarios for the electricity mix in Saudi Arabia are evaluated. The findings show that electrified processes could lead to substantial reductions in global warming potential (GWP), with the carbon emission intensity of the electricity grid playing a pivotal role in determining the environmental performance of these technologies. The integration of low carbon electrification with CO2 capture has the potential to reduce the GWP by up to 73%, compared to a baseline scenario relying entirely on 100% Heavy Fuel Oil (HFO) as kiln fuel. Beyond GWP, the study also evaluates other non-climate impact indicators to identify potential environmental co-benefits and trade-offs associated with climate change mitigation efforts.
Decentralized Condition Monitoring for Distributed Wind Systems: A Federated Learning-Based Approach to Enhance SCADA Data Privacy
Authors: Li Gang , Wu Yusen , Yesha Yelena
Published: September 2024

The paper presents a new condition monitoring method for distributed wind systems (DWSs) by combining federated learning with supervisory control and data acquisition (SCADA) data. Federated learning facilitates training of a global model across decentralized SCADA datasets without actual data exchange. This method allows multiple DWSs to collectively contribute to training machine learning models without compromising data privacy. The framework aims to enhance the accuracy and efficiency of condition monitoring by leveraging operational data from SCADA systems. It enables collaborative learning across diverse geographical areas, identifying subtle patterns and anomalies indicative of potential faults or performance issues. The integration of SCADA data provides real-time insights into individual turbine health and performance, allowing for early detection of deviations from normal operating conditions. The federated learning model evolves to adapt to changing environmental and operational factors while maintaining data confidentiality. This condition monitoring method allows for collective improvement of monitoring models without exposing sensitive turbine-specific information, enhancing security and transparency. The synergy of federated learning and SCADA data represents a pioneering paradigm shift, promising to improve monitoring processes and knowledge sharing within the wind infrastructure, advancing reliability, performance, and sustainability in the face of operational challenges.
Optical Flow Diagnostics of Counter Fluidization of Gravity-Driven Moving Packed Bed for a CSP Receiver Section Featuring Staggered Array of Cylindrical Pins
Authors: Aider Youssef , Ma Zhiwen , Singh Prashant
Published: September 2024

Particle fluidized beds have the potential to improve the efficiency of heat transfer in concentrated solar receiver furnace for use in next generation concentrated solar power (CSP) plants. This study presents an experimental investigation on the flow characterization of vertically downward moving packed bed with counter fluidization through an array of jets. To control the bubble size and its distribution in the bubbling fluidized bed, an array of cylindrical pin fins was arranged uniformly across the test article. The flow visualization was performed on the surface of transparent glass coated with electrically conductive materials for electrostatic dissipation purposes. The image acquisition was carried out via high-speed camera at a frequency of ∼ 1kHz. The acquired images were analyzed in pairs with the help of a modern optical flow algorithm capable of calculating the movement of dense particle flow in the fluidized bed by tracking the light intensity of each predefined window of the frames. A comparison of fluidized beds with plane and pin-finned channels revealed distinct bubble behavior. Pin-finned channels were found to produce a larger number of small-sized bubbles, while plane channels generated fewer but larger bubbles at any given instant. The presence of pin fins was observed to reduce bubble size by preventing bubble merging and splitting larger bubbles when they encountered a pin.
Modeling of Hot and Cold Storage Silos With a Moving Packed-Bed Shell-and-Plate Heat Exchanger in a Particle Based Concentrated Solar Power System
Authors: Marton Matthew , Nanclares Juan Camilo , Ordonez Juan C. , Arias Jesus , Haynes Comas
Published: September 2024

The next generation of Concentrated Solar Power (CSP) systems is envisioned to use solid particles for heat collection and storage. This paper presents a computational model for a particle storage silo and for a heat exchanger in which hot solid particles exchange heat with super critical carbon dioxide that serves as the working fluid for the CSP power block. A novel storage silo model is presented in which the particles are modeled as a quasi-1D fin. All heat conduction through particles is calculated using the ZBS model for particle heat conduction. Silo geometry is based upon G3P3 requirements for thermal storage. The heat exchanger model is compared against previously completed models. Temperatures for the stored particles and insulation layers in a quasi steady-state configuration where the particles are emptied and refilled every 10 hours over a 100 hour period.
Temperature impact on acoustic wave reflection in quasi-collinear acousto-optic devices
Authors: Mantsevich Sergey N. , Kostyleva Ekaterina I.
Published: September 2024

Quasi-collinear geometry is a special configuration of acousto-optic (AO) diffraction that applies the acoustic wave reflection from the AO cell input optical face and provides an extremely large interaction length for achieving abnormally high spectral resolution of AO tunable filters. As a result, it becomes possible to implement the multifrequency diffraction which has found important applications for laser pulse shaping. The operation of quasi-collinear AO devices in the multifrequency diffraction regimen is accompanied by the appearance of the longitudinal and transverse temperature gradients in the crystal, mainly due to the acoustic power absorption. Temperature changes the AO cell material stiffness moduli, affecting the characteristics of the incident and reflected acoustic waves (propagation velocities and walk-off angles), and the reflection condition in general. On the example of paratellurite crystal is shown that the AO cell heating near the reflecting facet leads to a deviation of the reflected acoustic beam propagation direction from that specified during the AO cell manufacturing. The deviation magnitude depends on the reflection geometry choice and, in the paratellurite, may exceed several degrees, which adversely affects the AO diffraction characteristics, reducing the AO interaction efficiency and distorting the transmission function shape. The reflected beam deviation may be compensated by means of choosing the angle between the AO cell reflecting face and the piezoelectric transducer face, taking into account the operating AO device thermal regimen.
Genome sequence of
Sulfurimonas
sp. C5, a potential chemolithoautotrophic, sulfur-oxidizing bacterium isolated from a mangrove sediment
Authors: Yuan Qing , Wang Shufang , Wang ShaSha , Zhong Yangsheng , Jiang Lijing
Published: September 2024

Sulfurimonas
sp. strain C5 (MCCC 1A19556) is a strain with potential chemolithoautotrophic sulfur-oxidizing function, which is isolated from a mangrove sediment sample collected from Quanzhou Bay, Fujian Province, China. This report describes the genome sequence of strain C5, which possesses the gene sets for the sulfur-oxidizing pathway.
Genome sequence of dengue virus serotype 1 isolated from a pediatric patient enrolled in an Ivermectin trial in Thailand
Authors: Sayboonruan Preeyanuch , Songjaeng Adisak , Chin-Inmanu Kwanrutai , Proykhunthod Phitchapha , Prayongkul Dararat , Poraha Ranyikar , Mairiang Dumrong , Lapphra Keswadee , Chokephaibulkit Kulkanya , Punyadee Nuntaya , Avirutnan Panisadee
Published: September 2024

We sequenced the genome of dengue virus serotype 1 (DENV1) strain 4101301, isolated from a child with dengue fever in Thailand and cultured in C6/36 mosquito cells. These data are crucial for studying DENV1’s genetic diversity, evolution, and epidemiology and advancing the knowledge for developing antiviral drugs and vaccines targeting DENV.
Genome sequences of
Pseudomonas
sp. strain FFPRI_1 and
Photorhabdus temperata
strain FFPRI_2, isolated from the entomopathogenic nematode,
Heterorhabditis megidis
Authors: Takatsuka Jun , Maehara Noritoshi
Published: September 2024

The complete genome sequences of two bacteria isolated from an entomopathogenic nematode are reported. The genome sizes of
Pseudomonas
sp. strain FFPRI_1 and
Photorhabdus temperata
strain FFPRI_2 are 7,521,420 bp long with 63% G+C content and 5,483,510 bp long with 43.8% G+C content, respectively.
Two distinct
Dehalobacter
metagenome-assembled genomes from anaerobic chloroform and dichloromethane degrading consortia
Authors: Bulka Olivia , Edwards Elizabeth A.
Published: September 2024

Here we present two metagenomes and two
Dehalobacter
metagenome-assembled genomes from subcultures of an anaerobic chloroform and dichloromethane degrading microbial community used for bioremediation. Our objective was to assemble and curate the genome(s) of
Dehalobacter
, key biodegraders in the culture, through repeated sequencing and joint assembly with previous datasets.
Gut microbiota-derived gamma-aminobutyric acid improves host appetite by inhibiting satiety hormone secretion
Authors: Li Shouren , Liu Mengqi , Han Yao , Liu Cong , Cao Shixi , Cui Yalei , Zhu Xiaoyan , Wang Zhichang , Liu Boshuai , Shi Yinghua
Published: September 2024

Globally, appetite disorders have become an increasingly prominent public health issue. While short-term appetite loss may seem relatively harmless, prolonged instances can lead to serious physical and mental damage. In recent years, numerous studies have highlighted the significant role of the “microbiota-gut-brain” axis in the regulation of feeding behavior in organisms, suggesting that targeting the gut microbiota may be a novel therapeutic strategy for appetite disorders. However, the molecular mechanisms through which the gut microbiota mediates the increase in host appetite and the causal relationship between the two remain unclear. Based on this, we conducted 16S rRNA sequencing to analyze the gut microbiota of rabbits with high and low feed intake, followed by fecal microbiota transplantation (FMT) and metabolite gavage experiments to elucidate the underlying mechanisms. Our research indicates that the high feed intake group exhibited significant enrichment of the
g__Bacteroides
and gamma-aminobutyric acid (GABA), and intragastric administration of GABA effectively promoted the host’s feeding behavior. The underlying mechanism involves GABA derived from the gut microbiota inhibiting the secretion of satiety hormones to enhance the host’s feeding behavior. Furthermore, the results of FMT suggest that differences in gut microbiota composition may be a contributing factor to varying levels of feed intake in the host. In conclusion, these findings emphasize the role of the gut microbiota-derived GABA, in increasing host feed intake, offering a new target for the treatment of appetite disorders from the perspective of gut microbiota.

IMPORTANCE

The incidence of anorexia is rapidly increasing and has become a global burden. Gut microbiota can participate in the regulation of host feeding behavior, yet the molecular mechanisms through which the gut microbiota mediates the increase in host appetite and the causal relationship between them remain unclear. In this study, we utilized 16S rRNA sequencing to investigate the composition of the gut microbiota in rabbits with varying levels of feed intake and employed fecal microbiota transplantation and gastric infusion experiments with gamma-aminobutyric acid (GABA) to elucidate the potential mechanisms involved. GABA derived from the gut microbiota can effectively enhance the host’s feeding behavior by inhibiting the secretion of satiety hormones. This discovery underscores the pivotal role of the gut microbiota in modulating host appetite, offering novel research avenues and therapeutic targets for appetite disorders.
A conserved two-component system senses intracellular iron levels and regulates redox balance in
Mycobacterium
spp.
Authors: Yadav Rahul , Saini Deepak Kumar
Published: September 2024

For bacteria, an intricate coordination between sensing and regulating iron levels and managing oxidative stress is required as their levels are tightly interlinked. While various oxidative stress and heme-based redox sensors have been reported for both pathogenic and non-pathogenic bacteria, the mechanisms governing the modulation of intracellular iron levels in response to changes in redox status remain unclear. In this study, a gene-inactivated strain of mycobacterial sensor kinase PdtaS showed dysregulated expression of genes associated with iron metabolism, including Fe-S clusters, NADH dehydrogenases, and iron uptake. The strain showed poor growth in nutrient-limiting conditions, a defect rescuable by heme but not by Fe
3+
supplementation. This observation was associated with the PAS domain of the PdtaS sensor kinase. Biochemical and biophysical experiments established heme-binding to the PAS domain and its inhibitory effect on PdtaS auto-kinase activity, suggesting that the absence of heme induces activation of this sensor kinase. Interestingly, despite having an endogenous heme biosynthetic pathway or even external heme supplementation, the ∆
pdtaS
mutant exhibited persistent low intracellular iron levels concomitant with elevated oxidative stress. Antioxidant supplementation mitigated growth defects, emphasizing the link between oxidative stress, intracellular iron levels, and PdtaS activity. RNA-IP identified key targets associated with redox homeostasis and iron metabolism as targets of the PdtaR response regulator. The study proposes a novel role for the PdtaS-PdtaR TCS in sensing heme, regulation of intracellular iron levels, and redox balance.

IMPORTANCE

The research article investigates the intricate interplay between bacteria’s ability to take and utilize iron without inducing excess iron’s toxic effects, including oxidative stress. The study shows that bacteria achieve this by sensing intracellular iron available as heme through a sensory protein PdtaS, which turns off when heme is in excess and prevents iron uptake and iron efflux. The process shields bacteria from generating Fe-dependent free radicals and allows it to maintain viability. The absence of sensor kinase abrogates all these processes, increasing bacteria susceptibility to ROS and thereby slowing growth. This feature of the sensor kinase PdtaS makes it an attractive co-therapeutic target for tuberculosis therapy, where its inhibition will prevent iron uptake, even in the presence of low iron, thereby halting bacterial proliferation.
Seasonal succession of endophyte and the association with active ingredients in
Rheum palmatum
Authors: Li Ni , Mao YiFan , Huang YaLi , Zhang LingXuan , Hou Lu , Liu XiaoJun , Du YaRong , Chen DaWei , Sun Kun
Published: September 2024

The endophyte is closely related to medicinal plant growth and development, stress resistance, and active ingredients’ accumulation. However, a seasonal succession of endophytes and the association with active ingredients is still unclear. In this study, we used high-throughput sequencing methods to compare the endophyte diversity of
Rheum palmatum
under different seasons and analyze the association between endophytes and five active ingredients. The results show that the diversity of endophytic fungi increased and then decreased, while bacterial diversity increased with the change of season. Community composition showed that the dominant genera of endophytic fungi were different under the different seasons, while the dominant genera of endophytic bacteria were
Delftia
. Analysis of co-occurrence network maps showed that the connectivity and complexity of endophytic fungi and bacterial networks decreased with the change of season. Spearman analysis indicated that the active ingredients of
R. palmatum
were significantly positive correlation with genera of endophytic fungi (
Chalara
). FUNGuild and PICRUSt predictive analysis indicated that the function of endophytic fungi and bacteria, respectively, were symbiotroph and metabolism, and relative abundances were different under the different seasons. Our results help elucidate the mechanism of medicinal plant–endophyte interaction.

IMPORTANCE

Through the investigation of the seasonal succession of endophytes and the association with active ingredients in
Rheum palmatum
, we found that the diversity and composition of endophytes in
R. palmatum
exhibited seasonal dynamics, and the active ingredients of
R. palmatum
showed a significantly positive correlation with the genus of endophytic fungi (
Chalara
). Our results may lay a foundation for understanding the interaction mechanism of endophyte and medicinal plant, and can also provide a theoretical basis for sustainable production of medicinal plants.
Wastewater-based intestinal protozoa monitoring in Shanghai, China
Authors: Jiang Yanyan , Yuan Zhongying , Wang Yaxue , Zhang Jing , Shen Yujuan , Cao Jianping
Published: September 2024

Intestinal protozoa
Cryptosporidium
spp.,
Giardia duodenalis
, and
Enterocytozoon bieneusi
have been implicated in serious waterborne outbreaks worldwide. Wastewater-based epidemiology (WBE) is a promising approach for evaluating the disease prevalence in a catchment population in that it monitors the contamination level of the intestinal pathogens in wastewater. We collected 48 urban wastewater samples (24 from influents and 24 from effluents) from the Yangpu Wastewater Treatment Plant (YPWTP) in Shanghai, China. We identified
Cryptosporidium
spp.,
G. duodenalis
, and
E. bieneusi
by nested polymerase chain reaction (PCR) amplification.
Cryptosporidium hominis
and subtype IdA14 were identified in two samples by analyzing the sequences of small subunit ribosomal RNA (SSU rRNA) and 60–kDa glycoprotein (
gp60
) genes, respectively. The
G. duodenalis
sub-assemblage AII (
n
= 8) and assemblage C (
n
= 4) in 12 samples were determined by analyzing triosephosphate isomerase (
tpi
) gene sequences. The
E. bieneusi
genotype A was identified in one sample by analyzing the sequence of the internal transcribed spacer (ITS) region of the rRNA gene. These findings suggest that improving wastewater treatment and monitoring the virility of pathogens in effluents is critical. We observed similar prevalence and genotypes/subtypes of the three intestinal protozoa in our wastewater samples as those reported in previous studies, providing evidence that WBE can be used as an effective epidemic management tool.

IMPORTANCE

Cryptosporidium
spp.,
Giardia duodenalis,
and
Enterocytozoon bieneusi
are common intestinal protozoa causing diarrhea. The infective oocysts, cysts, and spores released in feces can survive in different environments, including multiple types of water bodies. Humans can acquire these intestinal protozoan infections
via
the fecal-oral route as in waterborne transmission. Wastewater-based epidemiology can rapidly and reliably detect and monitor the emergence and spread of waterborne diseases. We detected
Cryptosporidium
spp.,
G. duodenalis,
and
E. bieneusi
in a wastewater treatment plant in Shanghai, China, reflecting the occurrence and genetic characterizations of the three intestinal pathogens from community members served by the wastewater treatment plant.
Neonatal pemphigus vulgaris
Authors: Aiholli Sanmitra , Inamadar Arun , Janagond Ajit B
Published: September 2024

A neonate presented to a tertiary clinic with blisters and erosions over his trunk and extremities. The mother had multiple erosions with crusts affecting the scalp, oral cavity and trunk present since the first trimester and worse since delivery. Skin biopsy for histopathology and direct immunofluorescence confirmed pemphigus vulgaris (PV) in the mother. Indirect immunofluorescence assays for serum antibodies against desmogleins 1 and 3 were positive in both mother and baby confirming a diagnosis of neonatal PV. The baby’s lesions healed spontaneously within 2 weeks, and the mother was clear at 2 months following treatment with rituximab.
Missed opportunity in acute coronary syndrome
Authors: Satti Zahir , Salim Tarik , Egred Mohaned
Published: September 2024

A man in late adolescence of Asian descent was admitted with cardiac-sounding chest pain and a history of flu-like symptoms a week prior to presentation with negative screening for the SARS-CoV-2 virus. His ECG showed lateral T-wave changes and pre-excitation pattern suggestive of an accessory pathway. High-sensitivity troponin T peak was significantly elevated to 2550 ng/L (normal reference range 0–11). He was initially treated for a suspected perimyocarditis. Transthoracic echocardiography revealed moderate left ventricular systolic dysfunction with regional wall motion abnormalities suggestive of coronary artery disease. Cardiac magnetic resonance imaging showed subendocardial delayed gadolinium enhancement with ischaemia and viability in the left circumflex (LCx) territory. He was then sent for a CT coronary angiogram for a suspected spontaneous coronary artery dissection, and subsequently, he discussed with our team and accepted for immediate transfer. He underwent coronary angiography and intravascular ultrasound-guided percutaneous coronary intervention to his LCx artery with a drug-coated balloon. Following that, and after a discussion with the electrophysiology team, he had an attempt at ablating his accessory pathway with partial success. He was discharged home in a stable condition.
Disseminated toxoplasmosis infection 20 years post kidney transplant
Authors: Chandler Shaun , Sundac Lana , Hawley Carmel
Published: September 2024

Kidney transplant recipients are at increased risk of opportunistic infections and malignancy, including space-occupying intracranial lesions. Here, we present a case of a patient presenting with multiple intracranial lesions in the context of a distant history of transplantation. MRI findings were consistent with a large subcortical enhancing lesion. Leading differentials included posttransplant lymphoproliferative disorder and cerebral cryptococcoma. Brain biopsy was undertaken along with PCR testing on tissue detectedToxoplasma gondiiand Epstein-Barr virus (EBV) DNA. Cerebral toxoplasmosis was diagnosed based on characteristic histology and negative EBV immunohistochemistry. This case demonstrates the difficulties and complexities in reaching a diagnosis in immunocompromised patients and the importance of brain biopsy.
Thyrotoxic periodic paralysis complicated by carbimazole-associated myositis
Authors: Kanagaretnam Harsan , Parameshwaran Kajanan , Ganda Kirtan , Seibel Markus Joachim
Published: September 2024

A male of East Asian background in his 30s presented to the emergency department with acute onset global muscle weakness, elevated creatine kinase, profound hypokalaemia and hyperthyroidism. A diagnosis of thyrotoxic periodic paralysis was made and the myopathy resolved promptly with potassium replacement. However, 3 months after being commenced on carbimazole for hyperthyroidism, the patient developed myalgias without weakness associated with an elevated creatine kinase. The myositis panel was negative, while a muscle biopsy showed nonspecific, mild myopathic changes with minimal lymphocytic inflammation. As a change in therapy from carbimazole to propylthiouracil resulted in prompt symptom improvement and normalisation of serum creatine kinase levels, a presumptive diagnosis of carbimazole-induced myositis was made. Genetic testing for hereditary skeletal muscle channelopathies did not identify any gene of interest.
Near-infrared spectroscopy in the diagnosis and management of acute internal carotid artery occlusion
Authors: Moses Andrew A , Zhigin Vadim , Desir Likowsky , Sy Heustein , Ellis Jason A
Published: September 2024

Acute internal carotid artery occlusion is a neurological emergency that can result in cerebral infarction. Superficial temporal artery to middle cerebral artery bypass is one option to treat a subset of such patients. Near-infrared spectroscopy (NIRS) is an emerging non-invasive technique that holds promise to facilitate the management of carotid occlusion patients by monitoring the oxygen saturation of specific brain areas at risk for hypoperfusion and infarction. This case report describes a man in his 50s who presented with left-sided weakness due to acute right internal carotid artery occlusion. The patient was successfully managed both medically and surgically while incorporating data from NIRS for decision-making.