Proof of concept in utilizing the peptidoglycan skeleton of pathogenic bacteria as antigen delivery platform for enhanced immune response.

Subunit vaccines are becoming increasingly important because of their safety and effectiveness. However, subunit vaccines often exhibit limited immunogenicity, necessitating the use of suitable adjuvants to elicit robust immune responses. In this study, we demonstrated for the first time that pathogenic bacteria can be prepared into a purified peptidoglycan skeleton without nucleic acids and proteins, presenting bacterium-like particles (pBLP). Our results showed that the peptidoglycan skeletons screened from four pathogens could activate Toll-like receptor1/2 receptors better than bacterium-like particles from Lactococcus lactis in macrophages. We observed that pBLP was safe in mouse models of multiple ages. Furthermore, pBLP improved the performance of two commercial vaccines in vivo. We confirmed that pBLP successfully loaded antigens onto the surface and proved to be an effective antigen delivery platform with enhanced antibody titers, antibody avidity, balanced subclass distribution, and mucosal immunity. These results indicate that the peptidoglycan skeleton of pathogenic bacteria represents a new strategy for developing subunit vaccine delivery systems.

Binder-Free MOF-Based and MOF-Derived Nanoarrays for Flexible Electrochemical Energy Storage: Progress and Perspectives.

The fast development of Internet of Things and the rapid advent of next-generation versatile wearable electronics require cost-effective and highly-efficient electroactive materials for flexible electrochemical energy storage devices. Among various electroactive materials, binder-free nanostructured arrays have attracted widespread attention. Featured with growing on a conductive and flexible substrate without using inactive and insulating binders, binder-free 3D nanoarray electrodes facilitate fast electron/ion transportation and rapid reaction kinetics with more exposed active sites, maintain structure integrity of electrodes even under bending or twisted conditions, readily release generated joule heat during charge/discharge cycles and achieve enhanced gravimetric capacity of the whole device. Binder-free metal-organic framework (MOF) nanoarrays and/or MOF-derived nanoarrays with high surface area and unique porous structure have emerged with great potential in energy storage field and been extensively exploited in recent years. In this review, common substrates used for binder-free nanoarrays are compared and discussed. Various MOF-based and MOF-derived nanoarrays, including metal oxides, sulfides, selenides, nitrides, phosphides and nitrogen-doped carbons, are surveyed and their electrochemical performance along with their applications in flexible energy storage are analyzed and overviewed. In addition, key technical issues and outlooks on future development of MOF-based and MOF-derived nanoarrays toward flexible energy storage are also offered.

Whole-Genome Sequence and Pathogenicity Analysis of Providencia Heimbachae Causing Diarrhea in Weaned Piglets.

Providencia heimbachae was previously identified in piglets with post-weaned diarrhea and associated with hindlimb paralysis. However, the pathogenic mechanisms and virulence factors of P. heimbachae are not fully known. Whole-genome sequence analysis will be helpful to extend our understanding of the characterization of P. heimbachae at a genomic level. In this study, we sequenced the whole genome of P. heimbachae for the first time using PacBio RS II sequencers and assembled de novo through hierarchical genome assembly process (HGAP). Furthermore, we performed further genome annotation. The genome of P. heimbachae 99101 consists of a circular chromosome (4,262,828 bp) and a circular plasmid (231,957 bp) with G + C contents of 40.43 and 47.16%, respectively. Genome-wide sequence analysis yielded a total of 286 predicted virulence factors, 178 resistance genes, 17 chaperone protein manipulators of fimbriae, 47 genes involved in the encoding of flagellin, 12 cell membrane-associated virulence genes, 18 Enterobacteriaceae common antigens, etc. Based on genome analysis, we preliminarily confirmed through animal experiments that the capsule was the virulence factor of P. heimbachae causing hindlimb paralysis in animals. Our study provides a genetic basis for further elucidation of the characteristics and functional mechanisms of P. heimbachae as a conditionally pathogenic bacterium, as well as a direction for research into the mechanism of action of P. heimbachae infecting humans, extending knowledge of P. heimbachae as an important zoonotic pathogen.

Lysinibacillus capsici 38,328 isolated from agricultural soils as a promising probiotic candidate for intestinal health.

There is an increasing interest in the use of spore-forming Bacillus spp. as probiotic ingredients on the market. However, probiotics Bacillus species are insufficient, and more safe Bacillus species were required. In the study, traditional fermented foods and soil samples were collected from more than ten provinces in China, and 506 Bacillus were selected from 109 samples. Using the optimized procedure, we screened nine strains, which successfully passed the acid, alkali, bile salt, and trypsin resistance test. Drug sensitivity test results showed that three Bacillus out of the nine isolates exhibited antibiotic sensitivity to more than 29 antibiotics. The three strains sensitive to antibiotics were identified by 16S ribosomal RNA, recA, and gyrB gene analysis, two isolates (38,327 and 38,328) belong to the species Lysinibacillus capsici and one isolate (37,326) belong to Bacillus halotolerans. Moreover, the three strains were confirmed safe through animal experiments. Finally, L. capsici 38,327 and 38,328 showed protections in the Salmonella typhimurium infection mouse model, which slowed down weight loss, reduced bacterial load, and improved antioxidant capacity. Altogether, our data demonstrated that selected L. capsici strains can be used as novel probiotics for intestinal health.

Dynamic of upper body sweat distribution in young males wearing fully encapsulated chemical protective ensembles.

Impermeability is a feature of fully encapsulated chemical protective ensembles (FCPE), which can affect people's sweat and affect their clothing's thermal-wet comfort. This study investigated the dynamics of upper-body sweat distribution in young males wearing FCPE and explored variations in sweat rate intra-region and inter-time for 10 young and healthy male college students. The study was carried in a climatic chamber (environment temperature 35 °C, relative humidity 60%) with participants exercising on a treadmill at 4 km/h, 5%. Sweat was collected using a 35-pad set of absorbent pads that were changed every 5 min during the course of the experiment. A total of 7-pad sets were collected with an average sweat rate of 389, 631, 920, 1137, 1100, 1211, and 1105 g m-2 h-1, respectively. The medial upper back, lateral lower back, medial upper chest, medial mid-back, and lateral top back had the highest sweat rates, with average values of 1406, 1278, 1198, 1181 and 1139 g m-2 h-1, respectively. The waist (with average values of 557, 370, 596, and 332 g m-2 h-1, respectively) and bottom zones (373, 398, 661, and 849 g m-2 h-1, respectively) had the lowest sweat rates. The above data showed that the role of FCPE in promoting body perspiration. The upper body may be split into three zones of sweat rates based on the distribution result allowing for the design of more comfortable clothing. The study includes the fundamental physiological data as well as the design recommendations for advanced personal protective equipment.

Tunable VUV frequency comb for 229mTh nuclear spectroscopy.

Laser spectroscopy of the 229mTh nuclear clock transition is necessary for the future construction of a nuclear-based optical clock. Precision laser sources with broad spectral coverage in the vacuum ultraviolet are needed for this task. Here, we present a tunable vacuum-ultraviolet frequency comb based on cavity-enhanced seventh-harmonic generation. Its tunable spectrum covers the current uncertainty range of the 229mTh nuclear clock transition.

Heat strain in chemical protective clothing in hot-humid environment: Effects of clothing thermal properties.

Heat strain experienced by individuals wearing chemical protective clothing (CPC) is severe and dangerous especially in hot-humid environment. The development of material science and interdisciplinary studies including ergonomics, physiology and heat transfer is urgently required for the reduction of heat strain. The aim of this paper was to study the relationship among clothing thermal properties, physiological responses and environmental conditions. Three kinds of CPC were selected. Eight participants wore CPC and walked (4 km/h, two slopes with 5% and 10%) on a treadmill in an environment with (35±0.5) °C and RH of (60±5)%. Core temperature, mean skin temperature, heart rate, heat storage and tolerance time were recorded and analyzed. Physiological responses were significantly affected by the clothing thermal properties and activity intensity in hot-humid environment. The obtained results can help further development of heat strain model. New materials with lower evaporative resistance and less weight are necessary to release the heat strain in hot-humid environments.

Rational synthesis of a hierarchical Mo2C/C nanosheet composite with enhanced lithium storage properties.

Transition metal carbides have been studied extensively as anode materials for lithium-ion batteries (LIBs), but they suffer from sluggish lithium reaction kinetics and large volume expansion. Herein, a hierarchical Mo2C/C nanosheet composite has been synthesized through a rational pyrolysis strategy, and evaluated as an anode material with enhanced lithium storage properties for LIBs. In the hierarchical Mo2C/C nanosheet composite, large numbers of Mo2C nanosheets with a thickness of 40-100 nm are uniformly anchored onto/into carbon nanosheet matrices. This unique hierarchical architecture can provide favorable ion and electron transport pathways and alleviate the volume change of Mo2C during cycling. As a consequence, the hierarchical Mo2C/C nanosheet composite exhibits high-performance lithium storage with a reversible capacity of up to 868.6 mA h g-1 after 300 cycles at a current density of 0.2 A g-1, as well as a high rate capacity of 541.8 mA h g-1 even at 5.0 A g-1. More importantly, this hierarchical composite demonstrates impressive cyclability with a capacity retention efficiency of 122.1% over 5000 successive cycles at 5.0 A g-1, which surpasses the cycling properties of most other Mo2C-based materials reported to date.

Noncollinear Enhancement Cavity for Record-High Out-Coupling Efficiency of an Extreme-UV Frequency Comb.

We demonstrate a femtosecond enhancement cavity with a crossed-beam geometry for efficient generation and extraction of extreme-ultraviolet (XUV) frequency combs at a 154 MHz repetition rate. We achieve a record-high out-coupled power of 600 µW, directly usable for spectroscopy, at a wavelength of 97 nm. This corresponds to a >60% out-coupling efficiency. The XUV power scaling and generation efficiency are similar to that achieved with a single Gaussian-mode fundamental beam inside a collinear enhancement cavity. The noncollinear geometry also opens the door for the generation of isolated attosecond pulses at >100 MHz repetition rate.

Bidirectional spin filter in a triple orbital molecule junction by tuning the magnetic field along a single direction.

Metal-molecule-metal junction is considered the basing block and key element of molecular spintronic devices, within which to generate spin polarized currents is one of the most fundamental issues for quantum computation and quantum information. In this paper, by employing a parallel triple orbital molecule junction with large inter-orbital tunneling couplings, we propose theoretically a bidirectional spin filter where both spin-up and spin-down currents could be obtained by simply adjusting the external magnetic field to different regimes along a single direction, and the filtered efficiencies could reach almost 100%. The Zeeman effect and the occupancy switching for the bonding and anti-bonding states are found to be responsible for the spin selective transport. We demonstrate that our scheme is robust for large parameter spaces of the orbital energy level, except the particle-hole symmetric point, and is widely suitable for the strong-, weak-, and non-interacting cases. To implement these problems, we use the Wilson's numerical renormalization group technique to treat such systems.

Polypyrrole-MXene coated textile-based flexible energy storage device.

Recently, more and more researchers have devoted their efforts to developing flexible electrochemical energy storage devices to meet the development of portable and wearable electronics. Among them, supercapacitors (SCs) have been widely studied due to their high specific capacitance and power density. However, most flexible SCs often use traditional carbon materials and transition metal oxides as electrode materials. In this paper, we used an easy and low-cost way to fabricate a flexible supercapacitor based on a new type of two-dimensional material, transition metal carbides, nitrides, or carbonitrides (MXenes). By taking full advantage of the hydrophilicity and metal conductivity of MXene nanosheets, an extremely simple "dipping and drying" method was used to achieve conductive textile electrodes with a specific capacitance of 182.70 F g-1, which is higher than reported for carbon nanotubes (CNTs) and active carbon. To further improve the capacitive performance of the MXene-based electrode and avoid the poor oxygen oxidation of MXene, polypyrrole (PPy) was electrochemically deposited on the surface of MXene textiles, thus producing a PPy-MXene coated textile electrode with a specific capacitance of 343.20 F g-1. In addition, a symmetrical solid-state supercapacitor based on MXene-PPy textiles was assembled, which achieved an energy density of 1.30 mW h g-1 (power density = 41.1 mW g-1). This work introduces a new type of MXene-based textile SC, which provides a promising candidate for flexible and wearable energy storage devices.