bluuebunny/crossref_metadata_2025 huggingface dataset:
Stochastic optimization scheduling of wind-photovoltaic-storage-hydrogen-water system in independent island zero-carbon microgrid
Authors: Liang Fuguang
Published: June 2024

A stochastic optimal scheduling strategy is being proposed for a wind-photovoltaic-storage-hydrogen-water system within a zero-carbon microgrid for independent islands. This strategy is aimed at addressing the challenge of sustainable energy resource supply prevalent in traditional islands, while also considering the demand response of seawater desalination. In order to harness the clean, low-carbon, and high-efficiency characteristics of hydrogen, an electrolytic water hydrogen production system is integrated into the power system to utilize wind power generation. The desalination equipment is regarded as a controllable load within the system. It is combined with a demand response strategy to maximize the full utilization of the desalination equipment for consuming wind power on the island. Furthermore, a two-stage stochastic optimization method is being employed to handle uncertainties related to wind and photovoltaic generation. The objective is to minimize the system’s operating cost. To solve this optimization problem, the commercial solver CPLEX is being utilized. Through comparative analysis across different scenarios, simulation results indicate that the proposed strategy effectively dissipates uncertainties in wind scenarios while concurrently reducing the overall system operation cost. This approach comprehensively considers the system’s economics, thus demonstrating its potential to efficiently promote wind power consumption.
Research on structural resonance of large axial fan in power plant
Authors: Kang Yu , Ao Jiapeng , Ma Guangyao
Published: June 2024

According to the structural characteristics of the axial fan, the causes of equipment resonance are analyzed. Four reference methods are proposed, including strengthen the structural stiffness, change the exciting frequency, weaken the exciting force, and strengthen the damping. The characteristics of the response treatment measures are discussed. Take the two-stage axial-induced draft fan of a 600 MW unit as an example, the axial resonance problem has been dealt with well by improving the support stiffness and reducing the excitation force. The research results and treatment can provide an experience reference for the analysis and treatment of the resonance problem of large axial fans.
Interval evaluation of wind power prediction based on skew-slash t distribution
Authors: Xin Wang , Zhao Lin Wang , Bo Zhou
Published: June 2024

Wind resources have characteristics of stochastic volatility, resulting in wind power forecast errors greatly. The short and medium-term wind power forecast error distribution of the actual wind farm operating system is analyzed, and a sharp peak and thick tail, with heavy tail and skewness characteristics, are presented. A skew-slash t distribution (SST distribution) is proposed to describe the error distribution of short-term wind power prediction, and the parameter estimation is carried out by probability density curve fitting. The fitting results of the wind power forecast error historical data of the Wind power plant based on SST distribution, t distribution, and t Location-slash distribution (TLS distribution) are obtained, and the fitting goodness and prediction accuracy are compared. The results show that the SST distribution can more effectively estimate the wind power prediction interval.
37Ar source on-demand production and deployment for low-energy nuclear recoil measurement in ReD liquid Argon TPC
Authors: Zakhary P. ,   the DarkSide collaboration
Published: June 2024

The search for light dark matter (< 10 GeV/c
2) has become increasingly important, since no conclusive evidence has been found in the higher dark matter (DM) mass region. In order to explore this light mass range, it is necessary to accurately model the response of the noble liquid time projection chamber (TPC) detectors, used in many experiments aimed at the direct measurement of DM, to low energy (< 1 keV) nuclear recoils (NRs). In this respect,
 37Ar provides an ideal calibration source in the low-energy region due to its two low-energy peaks at 0.27 and 2.82 keV following electron capture with a 35-day half-life. We propose a method to produce
 37Ar without chemical or heating treatments by using the 40Ca(n,α)37Ar reaction. This can be achieved by irradiating nano-CaO powder with a neutron source (e.g. AmBe) and allowing the produced 37Ar to diffuse into the argon used inside a double-phase TPC. By measuring the NR yields relative to those two low-energy points in the Recoil Directionality (ReD) experiment, other detectors can be cross-calibrated with the same source deployed. In this talk, the 37Ar source production, its deployment, and preliminary results will be presented.
Enhancement of the DUNE FD1 X-ARAPUCA Photon Detection Efficiency and upgrade of the FD2 Photon Collector
Authors: Cattadori C.M. ,   the DUNE collaboration
Published: June 2024

The Photon Detection System (PDS) of the first two DUNE far detectors (FD1 and FD2) is composed of 6000 and 672 photon detection units respectively, named X-Arapuca, of different size and geometry. The PDS will complement and boost the DUNE LArTPC for the detection of non beam events: the prompt light detection will improve their tagging, and at low energies it will enable the trigger and the calorimetry of the supernova neutrinos. The X-Arapuca unit is an assembly of several components: its Photon Detection Efficiency (PDE) depends both on the design of the assembly and on the grade and the coupling of the individual components. The X-Arapuca PDE is the driver of the Photon Detection System sensitivity, that in turn determines the sensitivity of the DUNE physics reach for the detection of core-collapse supernova within the galaxy and for nucleon decay searches. In this work we present an update of the absolute PDE of the FD1 X-Arapuca baseline design, measured in laboratory: 160 units of this are deployed in the scale 1:20 FD1 prototype hosted in the NP04 cryostat at the CERN neutrino platform. Further we show how to change the baseline design of the FD1 X-Arapuca, allowing to double its PDE. Finally we review a few selected features of the photon collector of the sixteen FD2 X-Arapuca recently deployed for the FD2 scale 1:20 prototype at CERN in the NP02 cryostat, and of the last six units that integrate the latest advancements.
A compact breath breathalyzer for identifying the non-alcoholic fatty liver disease biomarker
Authors: Wang D.Z. , Hua X.Y. , Hu G.Q. , Wang Z.H. , Yan F.F. , Zhang K.N. , Cheng C. , Li S.B. , Wu X.Y. , Wang H.R.
Published: June 2024

Non-alcoholic fatty liver disease (NAFLD) is a prevalent
chronic liver disease worldwide. Currently, its diagnosis relies
primarily on imaging and histological examinations, which are
invasive and prone to misdiagnosis in the early stage. To address
these limitations, detection and analysis of volatile organic
compounds (VOCs) in human breath can be a rapid and non-invasive
screening method for NAFLD. In this study, a compact breath
breathalyzer was developed, utilizing a miniaturized gas
chromatography chip with the STM32 microcontroller as the main
control chip to manage airflow, temperature, and receive terminal
signals from the photoionization detector. In the experiment, a gas
mixture comprising five VOCs (pentane, acetone, toluene, octane, and
decane) was selected as the simulated typical disease biomarkers in
human breath to investigate the breathalyzer's performance and
optimize testing conditions for multi-polar and wide-boiling-range
breath samples. Results show that the breathalyzer can detect
low-boiling components (< 100°C) such as the isoprene and
acetone, with a detection limit less than 50 ppb which are two
commonly biomarkers of NAFLD. Furthermore, breath samples were
collected from 35 non-diseased individuals, and NAFLD early-stage
patient samples were simulated by increasing the isoprene
concentration by 10 ppb. Convolutional neural network (CNN) were
used to identify the VOC signatures in gas chromatograms with
predictive accuracy of 85% for the classification model. Therefore,
the compact breath breathalyzer has potential application in the
rapid and early screening of NAFLD.
A thermionic electron gun to characterize silicon drift detectors with electrons
Authors: Urban K. , Biassoni M. , Carminati M. , Edzards F. , Fiorini C. , Forstner C. , Lechner P. , Nava A. , Siegmann D. , Spreng D. , Mertens S.
Published: June 2024

The TRISTAN detector is a new detector for electron
spectroscopy at the Karlsruhe Tritium Neutrino (KATRIN) experiment.
The semiconductor detector utilizes the silicon drift detector
technology and will enable the precise measurement of the entire
tritium β-decay electron spectrum. Thus, a significant
fraction of the parameter space of potential neutrino mass
eigenstates in the keV-mass regime can be probed. We developed a
custom electron gun based on the effect of thermionic emission to
characterize the TRISTAN detector modules with mono-energetic
electrons before installation into the KATRIN beamline. The
electron gun provides an electron beam with up to 25 keV kinetic
energy and an electron rate in the order of 105 electrons per
second. This manuscript gives an overview of the design and
commissioning of the electron gun. In addition, we will shortly
discuss a first measurement with the electron gun to characterize
the electron response of the TRISTAN detector.
Hadamard transformation based frequency response mismatch calibration for a 4-channel TIADC
Authors: Qian Lei , Zheng Yanze , Mei Sitao , Sun Sicheng , Xu Huiya , Guo Lianping , Zhao Yijiu
Published: June 2024

The time-interleaved analog-to-digital converter (TIADC) is
one of the most effective solutions for improving the sampling rate
of acquisition systems. However, the frequency response mismatch
between channels can seriously degrade the performance of the
system. In this paper, we propose a calibration method for frequency
response mismatches in 4-channel TIADC systems. Following the
construction of a four-channel TIADC model using a four-order
Hadamard matrix, the error signals were extracted using three
time-invariant filters and subsequently subtracted from the output
to complete the calibration. It uses the Hadamard transform instead
of the complex exponential modulator used in conventional
time-varying filter methods, which can further simplify the signal
processing without the necessity of complicated calculations. We
have employed a stimulated four-channel TIADC system to validate the
effectiveness of the proposed calibration technique. Moreover, in a
commercial 12.5 GSPS four-channel TIADC system, it is also
demonstrated that this approach is effective in improving the
spurious-free dynamic range of the system.
A novel generation design dipole magnet power supply of booster to storage ring transport line in NSRRC
Authors: Wong Yong-Seng , Liu Kuo-Bin , Liu Chen-Yao , Wang Bao-Sheng , Huang Jhao-Cyuan
Published: June 2024

The Taiwan Light Source (TLS) is a synchrotron radiation
facility located in Taiwan. The booster ring at TLS injects
electrons into the storage ring, which then circulates the electrons
to produce synchrotron radiation for various experiments. The Taiwan
Light Source (TLS) has been in service for more than 20 years, and
some of the power supplies used in the facility are old and hard to
maintain repair and the component are phase-out. The upgrade is
specifically aimed at replacing the power supply for the BTS
(Booster to Storage ring) transmission line with a new
machine. During the regular shunt down time, dipole magnet power
supply replacements were completed. The main reason for using the
Chroma 62075H-30E power supply is commonality, for this machine is
widely used in Taiwan Photon Source (TPS), and the output current of
the power supply is paralleled to a dipole magnet. Therefore, a
total of 17 power supplies are used in this upgrade planned to be
executed. This novel generation upgrade design is important because
the power supply for the BTS transmission line is critical for the
operation of the facility, as it is responsible for maintaining the
electron beam at a stable energy level as it is injected from the
booster ring into the storage ring. A more reliable and efficient
power supply can help improve the stability and quality of the
electron beam, leading to better experimental results and more
efficient use of the facility. Overall, this novel generation
upgrade design is part of the ongoing effort to modernize and
improve the infrastructure of the TLS, ensuring that it remains a
state-of-the-art research facility for years to come.
A novel framework for the assessment of hydro-meteorological risks taking into account nature-based solutions
Authors: Brogno L , Barbano F , Leo L S , Di Sabatino S
Published: June 2024

The growing exposure to hydro-meteorological hazards translates into increasing risks for people, territories, and ecosystems. The frequency of occurrence and magnitude of these hazards are expected to further increase in the next decades urging tangible decisions to reduce anthropogenic climate change and adapt to the risks to be faced. In this context, risk assessment is an essential tool for becoming aware of dangers and taking countermeasures. This paper proposes a novel predictive, yet holistic, framework that allows to take into account multiple risks classified according to six research fields, i.e. healthcare, society, ecosystem, heritage, infrastructure, and agriculture. Each contribution to the overall risk is evaluated in terms of economic losses and carbon-dioxide emissions that in turn affect adaptation ability and contribute to exacerbating climate change. Both economic losses and emissions are estimated as a cost per day to support political decision-making processes. In this regard, the framework integrates the effects of adaptation and mitigation strategies to include societal capacities to cope with hazards and respond to their potential consequences. As a guideline, this study reports a preliminary investigation of a heatwave event over a portion of Bologna Province (Italy) concluding that the current use of air-conditioning systems is not sustainable leading to a huge amount of losses. The novel framework can be adopted in future studies for selecting more cost-effective strategies as expected for Nature-based Solutions (NbS). The framework can indeed stand as a tool for estimating the local impact of NbS in the current or future climate scenarios.
Spatial synchrony, temporal clustering and dominant driver of streamflow droughts in Peninsular India
Authors: Sharma Shailza , Mujumdar P P
Published: June 2024

Understanding the spatio-temporal evolution of streamflow droughts and their relationship with potential causative processes is critical for effective drought management. This study assesses spatial synchrony and temporal clustering of streamflow droughts in six major river basins of Peninsular India. The importance of baseflow, rainfall deficits, soil moisture deficits and high temperatures in triggering streamflow droughts is also investigated to identify the dominant driver during the period 1981–2015. Spatial synchrony of streamflow droughts is investigated using multivariate Ripley’s K function and temporal clustering is evaluated using univariate Ripley’s K at various timescales. The interactions of streamflow droughts with potential causative processes are investigated using event coincidence analysis. At regional scale, streamflow droughts in peninsular catchments show strong spatial synchrony even at longer timescales. However, at basin scale, droughts in the catchments show strong spatial synchrony only at smaller timescales, behave independently of each other and achieve asynchrony with time, especially at longer timescales. Streamflow droughts show the strongest temporal clustering at smaller timescales and the strength of clustering decreases after a 3 year timescale. Rainfall deficits primarily control streamflow droughts in Peninsular India at a range of lags, except just before the onset of drought events where baseflow dominates. In addition, trigger coincidence rates of baseflow are lower than rainfall deficits but higher than soil moisture deficits and high temperatures at longer time lags.
Probing the structural, magneto-electronic, thermophysical, and thermoelectric properties of vanadium-based V2MnZ (Z = As, Ga) Heusler alloy: a computational assessment
Authors: Sharma Shruti , Ghosh Sukirti , Gupta Dinesh C
Published: June 2024

The structural, magneto-electronic, thermophysical and thermoelectric properties of vanadium-based V2MnZ (Z = As, Ga) alloys have been investigated using density functional theory simulation scheme and semiclassical Boltzmann transport methods. First of all, the structural characterization has been performed in ferromagnetic and non-magnetic states which signifies that both the alloys crystallized in C1b type structure with space group F-43m. We also computed the various thermodynamical parameters such as heat capacity (Cv), Debye temperature (θ
D), and grüneisen parameter (γ) of these materials, with the help of quasi-harmonic approximation (QHA) at pressures ranging from 0 to 20 GPa and temperatures ranging from 0 to 900 K. We have used the Boltzmann transport theory with the constant relaxation approximation as a basis for calculating various thermoelectric coefficients such as the Seebeck coefficient, power factor, total thermal conductivity and figure of merit. The efficient half-metallicity and thermoelectric responses contribute to spintronics and green energy harvesting technology.
Effective brain connectivity related to non-painful thermal stimuli using EEG
Authors: Santos Cuevas Diana Carolina , Campos Ruiz Roberto Esteban , Collina Denny Daniel , Tierra Criollo Carlos Julio
Published: June 2024

Understanding the brain response to thermal stimuli is crucial in the sensory experience. This study focuses on non-painful thermal stimuli, which are sensations induced by temperature changes without causing discomfort. These stimuli are transmitted to the central nervous system through specific nerve fibers and are processed in various regions of the brain, including the insular cortex, the prefrontal cortex, and anterior cingulate cortex. Despite the prevalence of studies on painful stimuli, non-painful thermal stimuli have been less explored. This research aims to bridge this gap by investigating brain functional connectivity during the perception of non-painful warm and cold stimuli using electroencephalography (EEG) and the partial directed coherence technique (PDC). Our results demonstrate a clear contrast in the direction of information flow between warm and cold stimuli, particularly in the theta and alpha frequency bands, mainly in frontal and temporal regions. The use of PDC highlights the complexity of brain connectivity during these stimuli and reinforces the existence of different pathways in the brain to process different types of non-painful warm and cold stimuli.
Inert structural transition in 4H and 6H SiC at high pressure and temperature: a Raman spectroscopy study
Authors: Maitani Shuhou , Sinmyo Ryosuke , Ishii Takayuki , Yoza Kenji
Published: June 2024

We conducted Raman spectroscopy measurements of 4H-SiC and 6H-SiC up to 69 GPa and 1023 K to assess the stability and bonding of SiC at high pressure and temperature. Both optic and acoustic modes were observed at wide pressure and temperature ranges. The temperature shifts of the Raman frequencies were fitted by the equation with the Bose–Einstein distribution function, and we found that the shifts were almost insensitive to the pressure. The mode Grüneisen coefficients weakly depend on the pressure and temperature, suggesting the sluggish transition of the crystal structure, unlike the previous experiments showing the transition or decomposition of SiC at high pressure and temperature conditions. Inert transitions are confirmed by Raman measurements and annealing experiments using multiple high-pressure apparatuses. The crystallinity may be a hidden critical parameter in the experiments to determine the stable polytypes of SiC under high pressure and temperature.
Comprehensive correlation analysis of electromechanical behavior in high-stretchable carbon nanotube/polymer composites
Authors: Jin Seong-Won , Go Myeong-Seok , Lee Youngu , Ryu Seunghwa , Lim Jae Hyuk
Published: June 2024

In this study, a comprehensive correlation analysis of highly stretchable carbon nanotube (CNT)/polymer composites was conducted to predict the change in electrical conductivities in response to uniaxial deformation. To this end, the representative volume elements (RVEs) were generated by randomly distributing CNTs in a polymer matrix using a Monte Carlo simulation algorithm. The effective electrical conductivity was then calculated through a network model. Under uniaxial tensile strain, where the length of CNTs was maintained constant and their configuration kept straight, CNT translation and rotation were considered along with the effects of tensile strain and shrinkage, incorporating Poisson’s ratio. The RVE configuration was updated to account for changes in the network under these conditions. To achieve a strong correlation between the simulation and test results from the previously published works, numerous trade-off studies have been conducted on the RVE size, geometric periodicity, the length of CNT fibers, the mixing ratio of CNT fibers of CNT/polymer composites, and tensile strain. From the results it can be seen that excellent correlations can be only achieved with careful control of the aforementioned parameters.
Characters of logarithmic vertex operator algebras and coloured invariants of torus links
Authors: Kanade Shashank
Published: June 2024

We show that the characters of

s
l

r

\mathfrak {sl}_r

versions of the

(
1
,
p
)

(1,p)

singlet and the

(
1
,
p
)

(1,p)

triplet vertex operator algebras arise as limits of appropriately coloured

s
l

r

\mathfrak {sl}_r

Jones invariants of certain torus links.
A novel method for high-sensitivity detection of SARS-CoV-2 using dual double-quenched fluorescence probes
Authors: Zhu Chunsen , Fang Hao , Ma Houshi , Xue Jinbing , Li Zeqin , Wu Xi , Luo Gangyin
Published: June 2024

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected many people around the world; fast and accurate detection of the virus can help control the spread of the virus. Reverse transcription-polymerase chain reaction (RT-PCR) is the gold standard method for SARS-CoV-2 detection. In this study, we improved the RT-PCR by proposing a novel method using dual double-quenched fluorescence probes. We used the improved probes to detect the plasmid DNA and RNA reference materials of SARS-CoV-2, respectively. The results show that, the background fluorescence intensity reduced by 50%, the fluorescence increment increased to 2.8 folds, and the Ct value significantly reduced by 3 or more, indicating that the detection sensitivity increased at least 8 times. In addition, we demonstrated that the improved probes have well performance in detecting SARS-CoV-2, with the minimum concentration of 6.2 copies/µL. This study will help biological companies develop better products for SARS-CoV-2 and other clinical pathogen infection.
Can developmental plasticity shape sexual competition and promote reproductive isolation?
Authors: Hubakk Kristin , Wylde Zachariah , Bonduriansky Russell
Published: June 2024

Environmental factors, such as dietary nutrients, can shape the expression of developmentally plastic sexual traits in many species. However, while there has been extensive research into the developmental plasticity of sexual traits at the individual level, the broader consequences of this variation at the population scale remain poorly understood. Here, we asked whether plastic responses to the developmental environment can shape sexual competition and initiate reproductive isolation between populations. We reared neriid flies, Telostylinus angusticollis, on nutrient-rich and nutrient-poor larval diets, generating adult flies that differed in body size and secondary sexual trait expression. We then investigated sexual competition in experimental populations from each developmental environment and tested for reproductive isolation between flies from mismatched environments. We found that, compared with poor-diet populations, rich-diet populations exhibited more frequent and escalated male–male combat and more frequent mating and mate-guarding. However, we found no evidence that sexual selection was affected by the developmental environment. Mismatched female–male pairs tended to take longer to mate and rich-diet females often rejected poor-diet males, but mismatched pairs were not less likely to mate within 1 h or produce viable offspring. Our findings suggest that developmental plasticity could generate dramatic differences in sexual competition between populations and could contribute to reproductive isolation.
Effects of Rock Type and Food Availability on Bioerosion by the Purple Sea Urchin, Strongylocentrotus purpuratus
Authors: Troha Lukas U , Narvaez Carla A , Russell Michael P
Published: June 2024

Synopsis

Purple sea urchins (Strongylocentrotus purpuratus) profoundly impact nearshore rocky coasts through their feeding habits. Their intense grazing sculpts substrates through bioerosion using their teeth and spines and controls the alternative stable state dynamic between kelp bed and urchin barrens. These states have contrasting food availability for sea urchins, with abundant food in kelp beds and scarce food in barren grounds. However, the relationship between food availability and bioerosion is unknown. We predicted that when kelp is available, it would ameliorate the action of teeth on the substrate. Our 11-week long, 2 × 2 factorial experiment, crossed community state (kelp present vs absent) and rock type (sandstone vs mudstone). We also quantified the contribution of spine abrasion to bioerosion on the two rock types. The bioerosion rates did not differ between treatments with and without kelp. Although there was no significant difference in net bioerosion between the rock types, there was a large difference between the proportion of bioerosion from teeth vs spine abrasion. Approximately a third of the sandstone bioerosion was from spines whereas less than 2% of mudstone bioerosion could be attributed to spines. As anticipated, growth of sea urchins fed kelp ad-libitum was higher than food-limited sea urchins. Surprisingly, sea urchins on mudstone (which has a higher organic component) grew faster than sea urchins on sandstone. Although bioerosion rates may not differ on a per-urchin basis between community states, the sea urchin population densities between kelp beds and urchin barrens likely causes a difference in net bioerosion between these communities. Our results point to the importance of lithology on the mechanics of sea urchin bioerosion. Differences in texture, grain size, and hardness of rock substrates undoubtedly contribute to bioerosion rates and dynamics.
Exact and numerical solutions of a free boundary problem with a reciprocal growth law
Authors: McDonald N R , Harris Samuel J
Published: June 2024

A two-dimensional free boundary problem is formulated in which the normal velocity of the boundary is proportional to the inverse of the gradient of a harmonic function $T$. The field $T$ is defined in a simply connected region which includes the point at infinity where it has a logarithmic singularity. The growth problem in which the boundary expands outwards is formulated both in terms of the Schwarz function of the boundary and a Polubarinova–Galin equation for the conformal map of the region from the exterior of the unit disk. An expanding free boundary is shown to be stable and explicit solutions for growing ellipses and a class of polynomial lemniscates are derived. Numerical solution of the Polubarinova–Galin equation is used to compute the evolution of the boundary having other initial shapes.
Antibiotic resistance in Mycobacterium tuberculosis alters tolerance to cell wall-targeting inhibitors
Authors: Jowsey William J , Cook Gregory M , McNeil Matthew B
Published: June 2024

Background

A limited ability to eliminate drug-resistant strains of Mycobacterium tuberculosis is a major contributor to the morbidity of TB. Complicating this problem, little is known about how drug resistance-conferring mutations alter the ability of M. tuberculosis to tolerate antibiotic killing. Here, we investigated if drug-resistant strains of M. tuberculosis have an altered ability to tolerate killing by cell wall-targeting inhibitors.

Methods

Bacterial killing and MIC assays were used to test for antibiotic tolerance and synergy against a panel of drug-resistant M. tuberculosis strains.

Results

Our results demonstrate that vancomycin and thioacetazone exhibit increased killing of diverse drug-resistant strains. Mutations in mmaA4 and mmpL3 increased vancomycin killing, which was consistent with vancomycin synergizing with thioacetazone and MmpL3-targeting inhibitors. In contrast, mutations in the mce1 operon conferred tolerance to vancomycin.

Conclusions

Overall, this work demonstrates how drug-resistant strains experience perturbations in cell-wall production that alters their tolerance to killing by cell wall-targeting inhibitors.
A Comparative Analysis of Two Commonly Used FDA-Approved Immunoassays for Fentanyl Detection
Authors: Lam K H Brian , Menlyadiev Marlen , Buggs Vincent , Parnprome Suttida , Pesce Amadeo , Suhandynata Raymond T , Fitzgerald Robert L , Song Lu , Metushi Imir G
Published: June 2024

Background

Given the opioid epidemic, fentanyl screening in urine has become increasingly important. Immunoassays remain the most common screening methodology due to the high throughput and ease of integration into automated chemistry systems. The fentanyl ARK II from Ark Diagnostics is a widely used immunoassay, while a novel fentanyl assay called FEN2 by Lin-Zhi has become available on the Roche platform. Here, we evaluate and compare their performance.

Methods

Four hundred and thirty-four urine samples were analyzed for fentanyl across the Lin-Zhi FEN2 and ARK II assays on the Cobas c502 platform. Samples were analyzed immediately upon request for drug of abuse screening or frozen for subsequent analysis. For confirmation testing, a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method with a limit of detection of 1 ng/mL for fentanyl/norfentanyl was used. Any sample with either fentanyl or norfentanyl above the LC-MS/MS cutoff was deemed positive.

Results

The ARK II had 11 false negatives and 7 false positives, while the Lin-Zhi FEN2 had 12 false negatives and 2 false positives. This resulted in ARK II having a sensitivity and specificity of 90.4% and 97.8% respectively, while Lin-Zhi FEN2 had a sensitivity and specificity of 89.5% and 99.4%.

Conclusions

Both the ARK II and Lin-Zhi FEN2 immunoassays detected fentanyl well. Overall, the Lin-Zhi assay had slightly better specificity than ARK II, in our data set. While some discrepant results were observed between the 2 immunoassay systems, most occurred near the immunoassay detection cutoffs.
Role and significance of virus–bacteria interactions in disease progression
Authors: Pokhrel Vatsala , Kuntal Bhusan K , Mande Sharmila S
Published: June 2024

Understanding disease pathogenesis caused by bacteria/virus, from the perspective of individual pathogen has provided meaningful insights. However, as viral and bacterial counterparts might inhabit the same infection site, it becomes crucial to consider their interactions and contributions in disease onset and progression. The objective of the review is to highlight the importance of considering both viral and bacterial agents during the course of coinfection. The review provides a unique perspective on the general theme of virus−bacteria interactions, which either lead to colocalized infections that are restricted to one anatomical niche, or systemic infections that have a systemic effect on the human host. The sequence, nature, and underlying mechanisms of certain virus−bacteria interactions have been elaborated with relevant examples from literature. It also attempts to address the various applied aspects, including diagnostic and therapeutic strategies for individual infections as well as virus–bacteria coinfections. The review aims to aid researchers in comprehending the intricate interplay between virus and bacteria in disease progression, thereby enhancing understanding of current methodologies and empowering the development of novel health care strategies to tackle coinfections.
Development and Performance Evaluation of a New Test Kit for Quantifying the Degree of DNA Fragmentation
Authors: Toyota Kazuki , Noma Satoshi , Kikuchi Yosuke , Satou Megumi , Tanaka Tomoki , Takiya Toshiyuki , Kokutani Ryota , Minegishi Yasutaka , Futo Satoshi , Takabatake Reona , Kitta Kazumi , Mano Junichi
Published: June 2024

Background

PCR-based genetic testing of agricultural products and foods is widely used for detecting various analytical targets such as genetically modified organisms and food allergens. However, it is difficult to obtain accurate genetic testing results from processed foods because DNA is fragmented by heat and pressure during food processing. Thus, we previously developed an analytical method to quantitatively evaluate the degree of DNA fragmentation for the purpose of QC of genetic testing for processed foods.

Objective

Our previous analytical method requires four PCR primer sets, resulting in high reagent costs and heavy analytical workloads. Therefore, we attempted to develop an easy-to-use test kit for quantifying the degree of DNA fragmentation and to evaluate its analytical performance.

Methods

To simplify the analysis procedure, we used only two primer sets. In addition, no-fragmentation control templates were prepared to obtain stable measurement results. The precision of the simplified analysis was evaluated through blind tests between laboratories.

Results

It was confirmed that plant species and extracted DNA concentrations had little effect on analysis with the newly developed test kit. In addition, the analytical values indicating the degree of DNA fragmentation exhibited small variability between laboratories.

Conclusion

We confirmed the high practicality of the developed test kit. Because DNA fragmentation in cells is a universal phenomenon, we anticipate that the test kit will be used not only for QC of genetic testing but also for food testing, medical diagnostics, and other applications in a range of fields.

Highlights

The newly developed test kit enables quantitative evaluation of the degree of DNA fragmentation in a simple manner.
Understanding the Complexity of Microbiology Method Validation to Meet State-Specific Requirements for Cannabis
Authors: Bird Patrick , Mills John , Johnson Ronald , McIntyre Maria , Valadez Azucena
Published: June 2024

Background

Federal legislation still prohibits the cultivation, sale, and consumption of cultivars of delta 9-tetrahydrocannabinol cannabis (>0.3%); however, as of November 2022, 39 states have legalized cannabis and cannabis derived products for medicinal consumption and 21 states have legalized for adult-use consumption. This state-by-state approach has produced a patch work of regulations that multi-state operators (MSOs) must learn to navigate. Furthermore, cannabis laboratories often lack the space and skill needed to perform method validations, adding another layer of complexity. While these barriers exist, it is paramount for MSOs to demonstrate the fitness of purpose of their methods.

Objective

This review presents the complexity that an MSO navigated in developing microbiology method validation study designs for two proprietary real-time PCR (RT-PCR) assays to meet four state (California, Florida, Michigan, and Oklahoma) testing requirements. The testing in each state was conducted in addition to certification of the assays through the AOAC Performance Tested MethodSM (PTM) program.

Methods

Matrix studies were conducted targeting three analytes (Aspergillus spp., Salmonella spp., and Shiga toxin-producing Escherichia coli) as directed by the state regulatory authorities. For California, inclusivity and exclusivity studies were performed. The number of contamination levels, test portion replicates, and total target organisms evaluated varied by state. Culture confirmation was not performed outside of the AOAC PTM studies.

Results

Data from each study was collected, summarized, and provided to the state regulatory agencies. Review of the data consisted of identifying discrepant results and verification of controls. After review, each assay was certified for use in the respective state.

Conclusion

Requirements from each of the states demonstrate the complexities MSOs face and emphasize the need for a more standardized approach to streamline acceptance of alternative methods.

Highlights

While varying state regulations can be complex, validation studies performed for the candidate methods have led to adoption across 31 states.
Horizontal sodium density variations for laser guide star tip-tilt measurements
Authors: Holdorf Erin , Martínez-Rey Noelia
Published: June 2024

Adaptive optics, particularly with laser guide stars, has revolutionized ground-based astronomy. However, one known limitation is the requirement of a natural guide star to retrieve tip-tilt information. This is the limiting factor in the overall achievable sky coverage with adaptive optics systems as natural guide stars are not available for all science targets. There have been numerous different techniques proposed to overcome this limitation; however, many are restricted by current technology. This work investigates the use of density perturbations in the sodium layer to retrieve the tip-tilt information. In this work, we identify atmospheric gravity waves as a mechanism that could cause perturbations in the sodium layer density. Archival hydroxyl airglow data was analysed to assess whether the density perturbations caused by atmospheric gravity waves are on the correct scales and have enough contrast to be used for laser guide star tip-tilt retrieval. This data showed a median contrast of 1.9 per cent for a laser guide star with a full width half-maximum of 25 arcsec. Then to determine if these perturbations would be visible with a laser guide star at a high enough signal-to-noise ratio, the Mathematica package LGSBloch was utilized. The CaNaPy laser guide star R&D facility was chosen to model as it has a state-of-the-art 70 W sodium laser. Promising results were found when modelling this method with the CaNaPy facility as a framework. This demonstrates that if these same perturbations were present in the sodium layer, sodium density variations are a potential mechanism to retrieve tip-tilt using laser guide stars.
A radio quasi-periodic oscillation in the blazar PKS J2156−0037
Authors: Mao Lisheng , Zhang Xuemei
Published: June 2024

The detection of quasi-periodic oscillations (QPOs) in blazar light curves is crucial for understanding their nature and fundamental physical processes. PKS J2156−0037 (z = 0.495), a blazar monitored by the Owens Valley Radio Observatory (OVRO) 40-m radio telescope, is the subject of this study. We searched for the presence of QPOs in the publicly available 15 GHz light curve of PKS J2156−0037, spanning 2008 January to 2020 January. We employed four well-established methods (the Jurkevich method, the generalized Lomb–Scargle periodogram, the weighted wavelet Z-transform, and the redfit method) that offer complementary strengths for robust periodicity detection. A consistent and statistically significant QPO signal was detected with a periodicity of around 611 d (at least 4.26σ local significance) and a global significance exceeding 99.83 per cent (or 2.92σ) based on Monte Carlo simulations with 105 simulated light curves (assuming underlying red-noise processes). This is the first reported detection of such a variability feature in this object. The possible physical mechanisms responsible for radio QPOs in blazars are discussed briefly.
Combined therapeutic strategy based on blocking the deleterious effects of AGEs for accelerating diabetic wound healing
Authors: Yang Yang , Huang Siwen , Ma Qing , Li Ning , Li Runchu , Wang Yongjun , Liu Hongzhuo
Published: June 2024

Diabetic foot ulcer is a serious complication of diabetes. Excessive accumulation of advanced glycation end products (AGEs) is one of the critical pathogenic factors in postponing diabetic wound healing. The main pathogenic mechanisms of AGEs include inducing cellular dysfunction, prolonging inflammatory response, increasing oxidative stress and reducing endogenous nitric oxide (NO) production. Combination therapy of blocking the deleterious effects of AGEs and supplementing exogenous NO is hypothesized to promote diabetic wound healing. Here, we presented nanoparticles/hydrogel composite dressings to co-delivery rosiglitazone and S-nitroso glutathione into the wound bed. The designed co-delivery system augmented the survival of fibroblasts, reduced oxidative stress levels, reversed the change of mitochondrial membrane potential and decreased the proinflammatory cytokine expression. Local sustained release of therapeutic agents significantly improved the wound healing of diabetic rats including increasing the wound closure rate, alleviating inflammation, promoting collagen fiber production and angiogenesis. Our finding indicated this local deliver strategy aimed at inhibiting the toxic effects of AGEs has great clinical potential for diabetic wound treatment.
Effector Protein Serine Carboxypeptidase FgSCP Is Essential for Full Virulence in Fusarium graminearum and Is Involved in Modulating Plant Immune Responses
Authors: Liu Kouhan , Wang Xintong , Qi Yuzhe , Li Ying , Shi Yifeng , Ren Yanyan , Wang Aolin , Cheng Peng , Wang Baotong
Published: June 2024

Fusarium head blight caused by Fusarium graminearum is a significant pathogen affecting wheat crops. During the infection process, effector proteins are secreted to modulate plant immunity and promote infection. The toxin deoxynivalenol is produced in infected wheat grains, posing a threat to human and animal health. Serine carboxypeptidases (SCPs) belong to the α/β hydrolase family of proteases and are widely distributed in plant and fungal vacuoles, as well as animal lysosomes. Research on SCPs mainly focuses on the isolation, purification, and production of a small number of fungi. The role of SCPs in plant secretion, growth and development, and stress resistance has also been extensively studied. However, their functions in F. graminearum, a fungal pathogen, remain relatively unknown. In this study, the biological functions of the FgSCP gene in F. graminearum were investigated. The study revealed that mutations in FgSCP affected the nutritional growth, sexual reproduction, and stress tolerance of F. graminearum. Furthermore, the deletion of FgSCP resulted in reduced pathogenicity and hindered the biosynthesis of deoxynivalenol. The upregulation of FgSCP expression 3 days after infection indicated its involvement in host invasion, possibly acting as a “smokescreen” to deceive the host and suppress the expression of host defensive genes. Subsequently, we confirmed the secretion ability of FgSCP and its ability to inhibit the cell death induced by INF1 in Nicotiana benthamiana cells, indicating its potential role as an effector protein in suppressing plant immune responses and promoting infection. In summary, we have identified FgSCP as an essential effector protein in F. graminearum, playing critical roles in growth, virulence, secondary metabolism, and host invasion.
Estimating the Prevalence of Using Suspected Counterfeit Medications in the General Population
Authors: Jewell Jennifer S. , Bemis Elizabeth A. , Black Joshua C.
Published: June 2024

Introduction

Counterfeit medications, sometimes referred to as “fake” or falsified drugs or pills, are drugs that are illicitly manufactured but designed to look like legitimate pharmaceuticals. Counterfeit medications are a growing public health concern. This study estimated the prevalence of self-reported use of suspected counterfeit medications by adults in the US and to assess what ingredients these individuals suspected were in the counterfeit medications.

Methods

This general population survey, drawn from an online panel, was administered across 2 waves in 2022 (15 April 3 June and 9 September 21 October) to 59,041 adults aged 18 and older. Statistical calibration weighting was used to calculate estimates representative of the national adult population.

Results

An estimated 1.8% (95% CI 1.7%–1.9%) of respondents, corresponding to approximately 4.6 million adults, suspected past 12-month use of counterfeit medications. Fentanyl was the most commonly suspected ingredient in the counterfeit product (16.1%, 95% CI 12.8%–19.3%). The next most prevalent response was “I don’t know” (15.0%, 95% CI 11.0%–18.9%) followed by methamphetamine (14.9%, 95% CI 11.4%–18.4%).

Conclusions

These data show the scale of the issue in relation to other well established drug use data points in the US. System-level methods, such as drug scanning software, should be implemented to reduce the likelihood that counterfeit drugs end up in the hands of individuals.
Cup and Cage Reconstruction for Metastatic Acetabular Lesions Provides Functional Improvement and Cost-efficiency
Authors: Krumme John W. , Laubach Logan K. , Sharma Viraj , Domson Gregory F.
Published: June 2024

Objective:

Pathologic acetabular lesions have multiple surgical options proposed and no clearly defined optimal solution at this time. In this study, we present our cage and cup reconstruction method and analyze postoperative outcomes against previously published studies.

Patients and Methods:

Twenty-four patients from 2014 to 2020 with acetabular pathologic lesions treated with an antiprotrusio cage and cup reconstruction were identified. Patient charts were reviewed for operative time, blood loss, Musculoskeletal Tumor Society functional scores, follow-up, and complications.

Results:

The average blood loss was 727 mL, and the average postoperative Musculoskeletal Tumor Society score was 70.3, with an average improvement of 35.2 points from preoperative scores. The average cost of our construct per year was $1177 for patients surviving >1 year after surgery. Eleven (45%) patients had died of disease at an average survival time of 14.2 months.

Conclusion:

Our study compares well with historic reconstruction strategies for metastatic acetabular disease, showing that this cup/cage reconstruction provides a durable and perioperatively safe approach that provides functional improvement while remaining cost-efficient.

Level of Evidence:

Level IV.