J-aggregation is an efficient strategy for the development of fluorescent imaging agents in the second near-infrared window. However, the design of the second near-infrared fluorescent J-aggregates ...is challenging due to the lack of suitable J-aggregation dyes. Herein, we report meso-2.2paracyclophanyl-3,5-bis-N,N-dimethylaminostyrl BODIPY (PCP-BDP2) as an example of BODIPY dye with J-aggregation induced the second near-infrared fluorescence. PCP-BDP2 shows an emission maximum at 1010 nm in the J-aggregation state. Mechanism studies reveal that the steric and conjugation effect of the PCP group on the BODIPY play key roles in the J-aggregation behavior and photophysical properties tuning. Notably, PCP-BDP2 J-aggregates can be utilized for lymph node imaging and fluorescence-guided surgery in the nude mouse, which demonstrates their potential clinical application. This study demonstrates BODIPY dye as an alternate J-aggregation platform for developing the second near-infrared imaging agents.
The Moon has a magmatic and thermal history that is distinct from that of the terrestrial planets
. Radioisotope dating of lunar samples suggests that most lunar basaltic magmatism ceased by around ...2.9-2.8 billion years ago (Ga)
, although younger basalts between 3 Ga and 1 Ga have been suggested by crater-counting chronology, which has large uncertainties owing to the lack of returned samples for calibration
. Here we report a precise lead-lead age of 2,030 ± 4 million years ago for basalt clasts returned by the Chang'e-5 mission, and a
U/
Pb ratio (µ value)
of about 680 for a source that evolved through two stages of differentiation. This is the youngest crystallization age reported so far for lunar basalts by radiometric dating, extending the duration of lunar volcanism by approximately 800-900 million years. The µ value of the Chang'e-5 basalt mantle source is within the range of low-titanium and high-titanium basalts from Apollo sites (µ value of about 300-1,000), but notably lower than those of potassium, rare-earth elements and phosphorus (KREEP) and high-aluminium basalts
(µ value of about 2,600-3,700), indicating that the Chang'e-5 basalts were produced by melting of a KREEP-poor source. This age provides a pivotal calibration point for crater-counting chronology in the inner Solar System and provides insight on the volcanic and thermal history of the Moon.
Abstract
Background
The duration of humoral and T and B cell response after the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unclear.
Methods
We performed a ...cross-sectional study to assess the virus-specific antibody and memory T and B cell responses in coronavirus disease 2019 (COVID-19) patients up to 343 days after infection. Neutralizing antibodies and antibodies against the receptor-binding domain, spike, and nucleoprotein of SARS-CoV-2 were measured. Virus-specific memory T and B cell responses were analyzed.
Results
We enrolled 59 patients with COVID-19, including 38 moderate, 16 mild, and 5 asymptomatic patients; 31 (52.5%) were men and 28 (47.5%) were women. The median age was 41 years (interquartile range, 30–55). The median day from symptom onset to enrollment was 317 days (range 257 to 343 days). We found that approximately 90% of patients still have detectable immunoglobulin (Ig)G antibodies against spike and nucleocapsid proteins and neutralizing antibodies against pseudovirus, whereas ~60% of patients had detectable IgG antibodies against receptor-binding domain and surrogate virus-neutralizing antibodies. The SARS-CoV-2-specific IgG+ memory B cell and interferon-γ-secreting T cell responses were detectable in more than 70% of patients.
Conclusions
Severe acute respiratory syndrome coronavirus 2-specific immune memory response persists in most patients approximately 1 year after infection, which provides a promising sign for prevention from reinfection and vaccination strategy.
SARS-CoV-2-specific antibody and memory T and B cell responses were detectable in most patients approximately 1 year after infection, indicating that durable immunity against secondary COVID-19 disease is possible in most individuals.
An efficient aryl to vinyl 1,4‐palladium migration/Heck sequence was developed for the stereoselective synthesis of 1,3‐dienes. High stereoselectivity was observed not only for 1,3‐dienes bearing two ...similar aryl groups at terminal positions, but also for those with configurations shown to be unfavorable with previous methods.
1,4 all: An efficient aryl to vinyl 1,4‐palladium/Heck sequence has been developed for the stereoselective synthesis of 1,3‐dienes. High stereoselectivity was observed not only for 1,3‐dienes bearing two similar aryl groups at terminal positions, but also for those with configurations shown to be unfavorable with previous methods.
Persistent luminescence without excitation light and tissue autofluorescence interference holds great promise for biological applications, but is limited by available materials with long‐wavelength ...emission and excellent clinical potential. Here, we report that porphyrin derivatives can emit near‐infrared persistent luminescence over 60 min after cessation of excitation light or on interaction with peroxynitrite. A plausible mechanism of the successive oxidation of vinylene bonds was demonstrated. A supramolecular probe with a β‐sheet structure was constructed to enhance the tumor targeting ability and the photoacoustic and persistent luminescence signals. Such probes featuring light‐triggered function transformation from photoacoustic imaging to persistent luminescence imaging permit advanced image‐guided cancer surgery. Furthermore, peroxynitrite‐activated persistent luminescence of the supramolecular probe also enables rapid and precise screening of immunogenic cell death drugs.
Porphyrin derivatives that can emit near‐infrared persistent luminescence (PL) over 60 min are reported and a mechanism for the phenomenon is proposed. The derivatives are used to synthesize supramolecular probes with peroxynitrite‐activated PL and light‐triggered imaging‐modality transformation characteristics that permit improved biological uses.
Clustered regularly interspaced short palindromic repeats interference (CRISPRi) has provided an efficient approach for targeted gene inhibition. A non-model microorganism Halomonas species TD01 has ...been developed as a promising industrial producer of polyhydroxyalkanoates (PHA), a family of biodegradable polyesters accumulated by bacteria as a carbon and energy reserve compound. A controllable gene repression system, such as CRISPRi, is needed for Halomonas sp. TD01 to regulate its gene expression levels.
For the first time CRISPRi was successfully used in Halomonas sp. TD01 to repress expression of ftsZ gene encoding bacterial fission ring formation protein, leading to an elongated cell morphology with typical filamentous shape similar to phenomenon observed with Escherichia coli. CRISPRi was employed to regulate expressions of prpC gene encoding 2-methylcitrate synthase for regulating 3-hydroxyvalerate monomer ratio in PHBV copolymers of 3-hydroxybutyrate (HB) and 3-hydroxyvalerate (HV). Percentages of HV in PHBV copolymers were controllable ranging from less than 1 to 13%. Furthermore, repressions on gltA gene encoding citrate synthase channeled more acetyl-CoA from the tricarboxylic acid (TCA) cycle to poly(3-hydroxybutyrate) (PHB) synthesis. The PHB accumulation by Halomonas sp. TD01 with its gltA gene repressed in various intensities via CRISPRi was increased by approximately 8% compared with the wild type control containing the CRISPRi vector without target.
It has now been confirmed that the CRISPRi system can be applied to Halomonas sp. TD01, a promising industrial strain for production of various PHA and chemicals under open and continuous fermentation process conditions. In details, the CRISPRi system was successfully designed in this study to target genes of ftsZ, prpC and gltA, achieving longer cell sizes, channeling more substrates to PHBV and PHB synthesis, respectively. CRISPRi can be expected to use for more metabolic engineering applications in non-model organisms.
This paper investigates the post-fire mechanical properties of high strength structural steel (HSSS) of Q690, the Chinese Grade of steel with nominal yield strength of 690MPa. The test specimens were ...first heated to a temperature level (ranging from 300°C to 900°C), and then cooled down to ambient temperature. Two cooling methods were considered: cooling in air and cooling in water. Tensile coupon tests were conducted to determine the yield strength, ultimate strength, elastic modulus, ultimate elongation and stress-strain curves. The study found that high-temperature treatment and cooling method had significant influence on the yield strength, ultimate strength and ultimate elongation of the investigated steel for heating temperature level above 500°C, while their influence on elastic modulus was negligible. Besides, the post-fire mechanical properties of Q690 steel were compared with S690 steel and Chinese grade steels Q235 and Q460. It was found that difference exists between the post-fire mechanical properties of Q690 steel and S690 steel even though they had the same nominal yield strength, and the effect of fire experience on the mechanical properties were sensitive to the steel grade. Equations were proposed to determine the post-fire material properties of Q690 steel cooled in air and cooled in water, which would provide the fundamentals for appropriate post-fire evaluation of Q690 high strength steel structures.
•Post-fire mechanical properties of Q690 steel were experimentally studied.•Cooling methods affect the post-fire properties of Q690 steel.•Equations are proposed to calculate the post-fire mechanical properties of Q690.
Studies on ultraviolet light-emitting diode (UV-LED) water disinfection have shown advantages, such as safety, flexible design, and lower starting voltages. However, information about reactivation ...after UV-LED disinfection is limited, which is an important issue of UV light-based technology. In this study, the photoreactivation and dark repair of Escherichia coli after UV-LEDs and low pressure (LP) UV disinfection were compared. Four UV-LED units, 265 nm, 280 nm, the combination of 265 + 280 (50%), and 265 + 280 (75%) were tested. 265 nm LEDs was more effective than 280 nm LEDs and LP UV lamps for E. coli inactivation. No synergic effect for disinfection was observed from the combination of 265 and 280 nm LEDs. 265 nm LEDs had no different reactivation performances with that of LP UV, while 280 nm LEDs could significantly repress photoreactivation and dark repair at a low irradiation intensity of 6.9 mJ/cm2. Furthermore, the UV-induced damage of 280 nm LEDs was less repaired which was determined by endonuclease sensitive site (ESS) assay. The impaired protein activities by 280 nm LEDs might be one of the reasons that inhibited reactivation. A new reactivation rate constant, Kmax, was introduced into the logistic model to simulate the reactivation data, which showed positive relationship with the maximum survival ratio and was more reasonable to interpret the results of photoreactivation and dark repair. This study revealed the distinct roles of different UV lights in disinfection and reactivation, which is helpful for the future design of UV-LED equipment.
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•265 nm LEDs was more effective for E. coli disinfection.•No synergic effect for disinfection from the combination of 265 and 280 nm LEDs.•280 nm LEDs significantly reduced the reactivation processes.•Protein-damaging may be one reason that inhibited the reactivation.•New reactivation rate constant with clear physical meaning was introduced.
We designed micromechanical experiments to examine the deformation behaviors of austenitic stainless steels fabricated by additive manufacturing. Micro-pillars containing different dislocation cell ...sizes were produced from the bulk specimen, and were mechanically tested for direct assessment of cell size reliance of yield and plastic deformation processes. The results highlight the cruciality of dislocation density in determining the yield strength of additively manufactured stainless steels, challenging the previous viewpoint that the strength scales with the cell size. However, dislocation nucleation and hardening of these micro-pillars were found to be cell size-correlated, with easier dislocation nucleation for micro-pillars containing smaller cells.
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Adipocyte differentiation of bone marrow mesenchymal stem/stromal cells (BMSCs) instead of osteoblast formation contributes to age- and menopause-related marrow adiposity and osteoporosis. Vascular ...calcification often occurs with osteoporosis, a contradictory association called "calcification paradox". Here we show that extracellular vesicles derived from aged bone matrix (AB-EVs) during bone resorption favor BMSC adipogenesis rather than osteogenesis and augment calcification of vascular smooth muscle cells. Intravenous or intramedullary injection of AB-EVs promotes bone-fat imbalance and exacerbates Vitamin D3 (VD3)-induced vascular calcification in young or old mice. Alendronate (ALE), a bone resorption inhibitor, down-regulates AB-EVs release and attenuates aging- and ovariectomy-induced bone-fat imbalance. In the VD3-treated aged mice, ALE suppresses the ovariectomy-induced aggravation of vascular calcification. MiR-483-5p and miR-2861 are enriched in AB-EVs and essential for the AB-EVs-induced bone-fat imbalance and exacerbation of vascular calcification. Our study uncovers the role of AB-EVs as a messenger for calcification paradox by transferring miR-483-5p and miR-2861.
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