Bacterial bioluminescence holds significant potential in the realm of optical imaging due to the inherent advantages of bioluminescence and ease of operation. However, its practical utility is ...hindered by its low light intensity. The fusion of bacterial luciferase with a highly fluorescent protein has been demonstrated to significantly enhance autonomous luminescence. Nevertheless, the underlying mechanism behind this enhancement remains unclear, and there is a dearth of research investigating the mechanistic aspects of bioluminescence resonance energy transfer (BRET) luminescence, whether it occurs naturally or can be achieved through experimental means. In this study, we investigated the phenomenon of bacterial luciferase-based BRET luminescence employing a range of computational techniques, including structural modeling, molecular docking, molecular dynamics simulations, as well as combined quantum mechanics and molecular mechanics calculations. The theoretical findings suggest that the BRET luminescence occurs through resonance energy transfer between the excited bioluminophore and the ground chromophore within the protein complex dimer. The proposed mechanism of the protein complex dimer offers a microscopic understanding of the intriguing BRET phenomenon and has the potential to inspire further practical applications in the field of optical imaging.
Lignocellulosic biomass is the most abundant sustainable carbon source on the planet and has enormous potential to substitute fossil resources on the premise of cost-effective conversion. Efforts ...have been made to develop various lignocellulosic bioconversion strategies to overcome biomass recalcitrance, promote product conversion efficiency and reduce process cost. Consolidated bio-saccharification (CBS), a consolidated bioprocessing (CBP) derived strategy, is herein proposed for lignocellulose bioconversion by integrating enzyme production and hydrolysis steps but separating fermentation from the integrated process. This strategy employs cellulosome-producing microorganisms as a biocatalyst to enhance lignocellulose solubilization and produces lignocellulose-derived fermentable sugars as a platform product for fermentations aiming at various products. The success of CBS depends on robust biocatalysts with high activity, suitable pretreatments for efficient delignification, and downstream fermentations with process compatibility. The review introduces the updated progress on lignocellulose bioconversion following the CBS route, discusses key factors for optimization of the CBS process, and, more importantly, highlights challenges and promising solutions for the CBS strategy in the industrial application of lignocellulose bioconversion.
•Consolidated biosaccharification (CBS) is promising for lignocellulose conversion.•Several signs of progress have been made within the framework of CBS.•CBS depends on efficient cellulosome-producing biocatalysts.•CBS requires lignocellulosic substrates with low lignin content.•The development of compatible pretreatment and fermentations is critical.
Covalent Organic Frameworks (COFs), an emerging class of crystalline porous materials, are proposed as a new type of support for grafting lanthanide ions (Ln3+) and employing these hybrid materials ...as ratiometric luminescent thermometers. A TpBpy‐COF—prepared from 1,3,5‐triformylphloroglucinol (Tp) and 2,2′‐bipyridine‐5,5′‐diamine (Bpy) grafted with Eu/Tb and Dy acetylacetone (acac) complexes can be successfully used as a luminescent thermometer in the 10–360 K (Eu) and 280–440 K (Tb) ranges with good sensing properties (thermal sensitivity up to 1.403 % K−1, temperature uncertainty δT<1 K above 110 K). For the Eu/Tb systems, we observe an unusual and rarely reported behavior, that is, no thermal quenching of the Tb3+ emission, a result of the absence of ion‐to‐ligand/host energy back‐transfer. The LnCOF materials proposed here could be a new class of materials employed for temperature‐sensing applications following up on the well‐known luminescent metal–organic framework thermometers.
A hot candidate: Covalent organic frameworks (COFs) are reported to be an excellent support for the grafting of lanthanide ions/complexes and allow the development of novel types of luminescent thermometers. A unique behavior, that is, no thermal quenching of the Tb3+ emission, is observed in these LnCOF materials.
Magnetic drug targeting is a method by which magnetic drug carriers in the body are manipulated by external magnetic fields to reach the target area. This method is potentially promising in ...applications for treatment of diseases like cancers, nervous system diseases, sudden sensorineural hearing loss, and so on, due to the advantages in that it can improve efficacy, reduce drug dosage and side effects. Therefore, it has received extensive attention in recent years. Successful magnetic drug targeting requires a good magnet system to guide the drug carriers to the target site. Up to date there have been many efforts to design the magnet systems for targeted drug delivery. However, there are few comprehensive reviews on these systems. Here we review the progresses made in this field. We summarized the systems already developed or proposed, and categorized them into two groups: static field magnet systems and varying field magnet systems. Based on the requirements for more powerful targeting performance, the prospects and the future research directions in this field are anticipated.
Four highly porous covalent organic frameworks (COFs) containing pyrene units were prepared and explored for photocatalytic H2O2 production. The experimental studies are complemented by density ...functional theory calculations, proving that the pyrene unit is more active for H2O2 production than the bipyridine and (diarylamino)benzene units reported previously. H2O2 decomposition experiments verified that the distribution of pyrene units over a large surface area of COFs plays an important role in catalytic performance. The Py‐Py‐COF though contains more pyrene units than other COFs which induces a high H2O2 decomposition due to a dense concentration of pyrene in close proximity over a limited surface area. Therefore, a two‐phase reaction system (water‐benzyl alcohol) was employed to inhibit H2O2 decomposition. This is the first report on applying pyrene‐based COFs in a two‐phase system for photocatalytic H2O2 generation.
Four highly porous pyrene‐based covalent organic frameworks (COFs) were prepared for photocatalytic H2O2 generation. The reported findings highlight that the presence of pyrene active sites in very close proximity leads to unwanted H2O2 decomposition. Accordingly, a biphasic system (benzyl alcohol and water) was employed to inhibit H2O2 decomposition.
A graphene defect engineering strategy was proposed in this work to tailor the interface and mechanical properties of graphene/Cu composites. Plasma treatment was used to create surface defects ...(5–10 nm nanopores) on the basal-plane of starting graphene material but without considerably damaging the graphene structure. It was demonstrated that the CuxOy oxides were in situ formed at the defect sites of plasma-treated graphene in the sintering process, which played a bridging role in enhancing the interfacial adhesion of graphene with Cu matrix. Compared to the composites with untreated graphene, the composites with plasma-treated graphene exhibited a higher strength enhancement, and better interface stability in response to thermal cycling, which was ascribed to the CuxOy-coordinated improved interfacial bonding that provided efficient load transfer and thermal stress relaxation. Nevertheless, the overlong plasma treatment could severely damage the graphene structure and result in a reduced strength enhancement. This study suggests that the rational defect engineering of graphene is an efficient approach for optimizing the interface and mechanical properties of graphene/metal composites.
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We study security solutions for dual-functional radar communication (DFRC) systems, which detect the radar target and communicate with downlink cellular users in millimeter-wave (mmWave) wireless ...networks simultaneously. Uniquely for such scenarios, the radar target is regarded as a potential eavesdropper which might surveil the information sent from the base station (BS) to communication users (CUs), that is carried by the radar probing signal. Transmit waveform and receive beamforming are jointly designed to maximize the signal-to-interference-plus-noise ratio (SINR) of the radar under the security and power budget constraints. We apply a Directional Modulation (DM) approach to exploit constructive interference (CI), where the known multiuser interference (MUI) can be exploited as a source of useful signal. Moreover, to further deteriorate the eavesdropping signal at the radar target, we utilize destructive interference (DI) by pushing the received symbols at the target towards the destructive region of the signal constellation. Our numerical results verify the effectiveness of the proposed design showing a secure transmission with enhanced performance against benchmark DFRC techniques.
Abstract
Background
In December 2019, a series of pneumonia cases of unknown cause emerged in Wuhan, Hubei, China. In this study, we investigate the clinical and laboratory features and short-term ...outcomes of patients with coronavirus disease 2019 (COVID-19).
Methods
All patients with COVID-19 admitted to Wuhan University Zhongnan Hospital in Wuhan, China, between 3 January and 1 February 2020 were included. All those patients were with laboratory-confirmed infections. Epidemiological, clinical, and radiological characteristics; underlying diseases; laboratory tests; treatments; complications; and outcomes data were collected. Outcomes were followed up at discharge until 15 February 2020.
Results
The study cohort included 102 adult patients. The median age was 54 years (interquartile ranger, 37–67 years), and 48.0% were female. A total of 34 patients (33.3%) were exposed to a source of transmission in the hospital setting (as health-care workers, patients, or visitors) and 10 patients (9.8%) had a familial cluster. There were 18 patients (17.6%) who were admitted to the intensive care unit (ICU), and 17 patients died (mortality, 16.7%; 95% confidence interval, 9.4–23.9%). Those patients who survived were younger, were more likely to be health-care workers, and were less likely to suffer from comorbidities. They were also less likely to suffer from complications. There was no difference in drug treatment rates between the survival and nonsurvival groups. Those patients who survived were less likely to require admission to the ICU (14.1% vs 35.3% of those admitted). Chest imaging examinations showed that patients who died were more likely to have ground-glass opacity (41.2% vs 12.9% in survivors).
Conclusions
The mortality rate was high among the COVID-19 patients described in our cohort who met our criteria for inclusion in this analysis. The patient characteristics seen more frequently in those who died were the development of systemic complications following onset of the illness and a severity of disease requiring admission to the ICU. Our data support those described by others indicating that COVID-19 infection results from human-to-human transmission, including familial clustering of cases, and from nosocomial transmission. There were no differences in mortality among those who did or did not receive antimicrobial or glucocorticoid drug treatments.
The mortality rate was high among coronavirus disease 2019 patients. Patient characteristics seen more frequently in those who died included systemic complications following onset of the illness and a severity of disease requiring admission to the intensive care unit.
Summary
Polyethylene terephthalate (PET) is a mass‐produced synthetic polyester contributing remarkably to the accumulation of solid plastics waste and plastics pollution in the natural environments. ...Recently, bioremediation of plastics waste using engineered enzymes has emerged as an eco‐friendly alternative approach for the future plastic circular economy. Here we genetically engineered a thermophilic anaerobic bacterium, Clostridium thermocellum, to enable the secretory expression of a thermophilic cutinase (LCC), which was originally isolated from a plant compost metagenome and can degrade PET at up to 70°C. This engineered whole‐cell biocatalyst allowed a simultaneous high‐level expression of LCC and conspicuous degradation of commercial PET films at 60°C. After 14 days incubation of a batch culture, more than 60% of the initial mass of a PET film (approximately 50 mg) was converted into soluble monomer feedstocks, indicating a markedly higher degradation performance than previously reported whole‐cell‐based PET biodegradation systems using mesophilic bacteria or microalgae. Our findings provide clear evidence that, compared to mesophilic species, thermophilic microbes are a more promising synthetic microbial chassis for developing future biodegradation processes of PET waste.
Promising bioremediation strategies for plastics waste are of great importance and requirements. In our study, we constructed a recombinant Clostridium thermocellum strain expressing a secretory cutinase (LCC) as a thermophilic whole‐cell biocatalyst to degrade PET under high‐temperature condition (60°C). To our knowledge, this biocatalysis system demonstrates the highest PET degradation efficiency compared to reported whole‐cell‐based systems and also enjoys a low‐cost advantage over the free enzyme‐based process.
Abstract
Iron-chalcogenide superconductors have emerged as a promising Majorana platform for topological quantum computation. By combining topological band and superconductivity in a single material, ...they provide significant advantage to realize isolated Majorana zero modes. However, iron-chalcogenide superconductors, especially Fe(Te,Se), suffer from strong inhomogeneity which may hamper their practical application. In addition, some iron-pnictide superconductors have been demonstrated to have topological surface states, yet no Majorana zero mode has been observed inside their vortices, raising a question of universality about this new Majorana platform. In this work, through angle-resolved photoemission spectroscopy and scanning tunneling microscopy/spectroscopy measurement, we identify Dirac surface states and Majorana zero modes, respectively, for the first time in an iron-pnictide superconductor, CaKFe
4
As
4
. More strikingly, the multiple vortex bound states with integer-quantization sequences can be accurately reproduced by our model calculation, firmly establishing Majorana nature of the zero mode.
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