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"Feng, Zhe"
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Perfecting and extending the near-infrared imaging window
In vivo fluorescence imaging in the second near-infrared window (NIR-II) has been considered as a promising technique for visualizing mammals. However, the definition of the NIR-II region and the mechanism accounting for the excellent performance still need to be perfected. Herein, we simulate the photon propagation in the NIR region (to 2340 nm), confirm the positive contribution of moderate light absorption by water in intravital imaging and perfect the NIR-II window as 900–1880 nm, where 1400–1500 and 1700–1880 nm are defined as NIR-IIx and NIR-IIc regions, respectively. Moreover, 2080–2340 nm is newly proposed as the third near-infrared (NIR-III) window, which is believed to provide the best imaging quality. The wide-field fluorescence microscopy in the brain is performed around the NIR-IIx region, with excellent optical sectioning strength and the largest imaging depth of intravital NIR-II fluorescence microscopy to date. We also propose 1400 nm long-pass detection in off-peak NIR-II imaging whose performance exceeds that of NIR-IIb imaging, using bright fluorophores with short emission wavelength.Moderate light absorption by bio-tissue is conducive to the imaging performance. The second near-infrared window is perfected as 900–1880 nm, and 2080–2340 nm is proposed as the third near-infrared window.
Journal Article
Platelet-rich plasma for pilonidal disease: a systematic review
Objective
To examine the use of platelet-rich plasma (PRP) for treatment of pilonidal disease (PD) and thus provide a reference for clinical application.
Methods
A systematic review of PubMed and the Cochrane Library was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We considered all studies that reported the use of PRP for treatment of PD. Extracted data included the first author’s name, year of publication, study type, number of included patients, inclusion and exclusion criteria, interventions, anesthesia, application of PRP (source, preparation, dose, and operation), antibiotics, follow-up time, therapeutic outcomes, and adverse events.
Results
In total, eight randomized controlled trials and one prospective cohort study involving 809 patients were included. PRP reduced pain, accelerated healing, and reduced adverse events. The application of combined minimally invasive surgery achieved better results. However, overfilling of the wound with PRP in minimally invasive surgeries was shown to potentially increase the risk of adverse events.
Conclusion
PRP can be used as an adjuvant treatment in PD surgery to improve the therapeutic effect and reduce adverse events. The optimal combination of PRP and various factors is an important direction of future research.
INPLASY registration number: INPLASY2023100070.
Journal Article
Recent advances of functional nucleic acid-based sensors for point-of-care detection of SARS-CoV-2
This review focuses on critical scientific barriers that the field of point-of-care (POC) testing of SARS-CoV-2 is facing and possible solutions to overcome these barriers using functional nucleic acid (FNA)-based technology. Beyond the summary of recent advances in FNA-based sensors for COVID-19 diagnostics, our goal is to outline how FNA might serve to overcome the scientific barriers that currently available diagnostic approaches are suffering. The first introductory section on the operationalization of the COVID-19 pandemic in historical view and its clinical features contextualizes essential SARS-CoV-2-specific biomarkers. The second part highlights three major scientific barriers for POC COVID-19 diagnosis, that is, the lack of a general method for (1) designing receptors of SARS-CoV-2 variants; (2) improving sensitivity to overcome false negatives; and (3) signal readout in resource-limited settings. The subsequent part provides fundamental insights into FNA and technical tricks to successfully achieve effective COVID-19 diagnosis by using in vitro selection of FNA to overcome receptor design barriers, combining FNA with multiple DNA signal amplification strategies to improve sensitivity, and interfacing FNA with portable analyzers to overcome signal readout barriers. This review concludes with an overview of further opportunities and emerging applications for FNA-based sensors against COVID-19.
Graphical abstract
Journal Article
Mesoscale Convective Systems in DYAMOND Global Convection‐Permitting Simulations
This study examines the deep convection populations and mesoscale convective systems (MCSs) simulated in the DYAMOND (DYnamics of the atmospheric general circulation modeled on non‐hydrostatic domains) winter project. A storm tracking algorithm is applied to six DYAMOND simulations and a global high‐resolution satellite cloud and precipitation data set for comparison. The simulated frequencies of tropical deep convection and organized convective systems vary widely among models and regions, although robust MCSs are generally underestimated. The diurnal cycles of MCS initiation and mature stages are well simulated, but the amplitudes are exaggerated over land. Most models capture the observed MCS lifetime, cloud shield area, rainfall volume and movement speed. However, cloud‐top height and convective rainfall intensity are consistently overestimated, and stratiform rainfall area and amount are consistently underestimated. Possible causes for the model differences compared to observations and implications for future model developments are discussed. Plain Language Summary A new class of high‐resolution global atmosphere models is emerging for Earth system modeling. These new models can directly simulate convective storm systems and hold promises to improve the simulation of hydrological extremes such as flood‐producing rainfall and how they may change in future climate. This study assesses the fidelity of simulated convective storms from six global models against high‐resolution satellite observations. We find that the models simulate widely different frequency of convective storms in the tropics, but many do not produce storms that grow as large as observed. Several important aspects of observed storms such as the diurnal cycle, land‐ocean contrast, and storm rainfall amount are reasonably captured by the models; however, precipitation intensity is consistently overestimated and the storm rainfall area is too small. We further discussed potential causes for the model differences with observations and future model development needs. Key Points Deep convective clouds and mesoscale convective systems are tracked in global convection‐permitting simulations and satellite observations Models produce a diverse range of tropical deep convective systems and MCS frequencies and their proportions in key climate regions Models reasonably simulate tropical MCS diurnal cycle and some MCS characteristics, but overestimate MCS precipitation intensity
Journal Article
A multi-temperature universe can allow a sub-MeV dark photon dark matter
A
bstract
An analysis of sub-MeV dark photon as dark matter is given which is achieved with two hidden sectors, one of which interacts directly with the visible sector while the second has only indirect coupling with the visible sector. The formalism for the evolution of three bath temperatures for the visible sector and the two hidden sectors is developed and utilized in solution of Boltzmann equations coupling the three sectors. We present exclusion plots where the sub-MeV dark photon can be dark matter. The analysis can be extended to a multi-temperature universe with multiple hidden sectors and multiple heat baths.
Journal Article
Environmental Controls on MCS Lifetime Rainfall Over Tropical Oceans
Mesoscale convective systems (MCSs) contribute a majority of rainfall over tropical oceans. However, our understanding of the environmental controls on tropical oceanic MCS precipitation remains incomplete. Using 20‐year of satellite observations, reanalysis data, and MCS tracking, we found that MCSs initiating in a mesoscale environment with enhanced lower‐free‐tropospheric moisture, warmer middle troposphere, stronger low‐level ascent, and stronger deep‐layer (surface‐400 hPa) wind shear tend to produce more precipitation during their lifetimes. While most of these environmental factors are correlated with one another, the deep‐layer shear is not. A rapid pickup in MCS lifetime rainfall is found when the lower‐free‐tropospheric specific humidity exceeds 10 g kg−1. This nonlinearity is mostly dominated by the nonlinear increase in MCS area. On the other hand, both MCS area and rain rate increase quasi‐linearly with the deep‐layer shear. The increase in rain rate is related to the enhancement of heavy precipitating convective activity with deep‐layer shear. Plain Language Summary Cumulonimbus clouds over tropical oceans often organize into entities with rainfall covering a horizontal scale of hundreds of kilometers, which are called mesoscale convective systems (MCSs). Although oceanic MCSs contribute more than 60% of the total rainfall over the tropics, how their precipitation is affected by environmental conditions has not been systematically assessed. Using two decades of satellite observations, this study shows that tropical oceanic MCSs that occur in an environment with higher moisture content and larger vertical variations in horizontal winds tend to rain more during their lifetime. We found that the increase in ambient moisture helps MCSs last longer, grow over a larger area, and achieve a higher rainfall rate. On the other hand, larger vertical variations in horizontal winds lead to increased MCS area and MCS rainfall intensity. These results might inform future development of climate models to better represent MCSs over tropical oceans. Key Points Mesoscale convective system (MCS) lifetime rainfall increases nonlinearly with initial low‐level moisture and quasi‐linearly with deep‐layer shear MCS lifetime/rain rate increase quasi‐linearly, while area grows nonlinearly with lower‐tropospheric moisture Deep‐layer shear significantly increases the MCS rain rate by enhancing heavy precipitating convective activity
Journal Article
Recent Advances on Gallium-Modified ZSM-5 for Conversion of Light Hydrocarbons
Light olefins are key components of modern chemical industry and are feedstocks for the production of many commodity chemicals widely used in our daily life. It would be of great economic significance to convert light alkanes, produced during the refining of crude oil or extracted during the processing of natural gas selectively to value-added products, such as light alkenes, aromatic hydrocarbons, etc., through catalytic dehydrogenation. Among various catalysts developed, Ga-modified ZSM-5-based catalysts exhibit superior catalytic performance and stability in dehydrogenation of light alkanes. In this mini review, we summarize the progress on synthesis and application of Ga-modified ZSM-5 as catalysts in dehydrogenation of light alkanes to olefins, and the dehydroaromatization to aromatics in the past two decades, as well as the discussions on in-situ formation and evolution of reactive Ga species as catalytic centers and the reaction mechanisms.
Journal Article
A long-lived stop with freeze-in and freeze-out dark matter in the hidden sector
A
bstract
In extended supersymmetric models with a hidden sector the lightest
R
-parity odd particle can reside in the hidden sector and act as dark matter. We consider the case when the hidden sector has ultraweak interactions with the visible sector. An interesting phenomenon arises if the LSP of the visible sector is charged in which case it will decay to the hidden sector dark matter. Due to the ultraweak interactions, the LSP of the visible sector will be long-lived decaying outside the detector after leaving a track inside. We investigate this possibility in the framework of a U(1)
X
-extended MSSM/SUGRA model with a small gauge kinetic mixing and mass mixing between the U(1)
X
and U(1)
Y
where U(1)
Y
is the gauge group of the hypercharge. Specifically we investigate the case when the LSP of MSSM is a stop which decays into the hidden sector dark matter and has a lifetime long enough to traverse the LHC detector without decay. It is shown that such a particle can be detected at the HL-LHC and HE-LHC as an
R
-hadron which will look like a slow moving muon with a large transverse momentum
p
T
and so can be detected by the track it leaves in the inner tracker and in the muon spectrometer. Further, due to the ultraweak couplings between the hidden sector and the MSSM fields, the dark matter particle has a relic density arising from a combination of the freeze-out and freeze-in mechanisms. It is found that even for the ultraweak or feeble interactions the freeze-out contribution relative to freeze-in contribution to the relic density is substantial to dominant, varying between 30% to 74% for the model points considered. It is subdominant to freeze-in for relatively small stop masses with relatively larger stop annihilation cross-sections and the dominant contribution to the relic density for relatively large stop masses and relatively smaller stop annihilation cross-sections. Our analysis shows that the freeze-out contribution must be included for any realistic analysis even for dark matter particles with ultraweak or feeble interactions with the visible sector. A discovery of a long-lived stop as the lightest particle of the MSSM may point to the nature of dark matter and its production mechanism in the early universe.
Journal Article