Synthesis, Structures, and Reactivities of BCN-Heterocyclic B-N Chains.

The BCN-heterocyclic B-N chain compounds, the sodium and potassium salts of 3 and 4 anions (Na3, Na4, and K4), were synthesized by reactions of ethane 1,2-diamineborane (BH3NH2CH2CH2NH2BH3, 1) and propane 1,2-diamineborane (BH3NH2CH2CH2CH2NH2BH3, 2) with MH (M = Na and K). Then, the neutral B-N chain compounds 5 and 6 were prepared with dehydrogenation of [NH4]3 and [NH4]4, formed by metathesis reactions of Na3 and Na4 with NH4Cl or NH4SCN, respectively. Compounds 7 and 8, analog 5, were also prepared using pyridine and 4-methoxypyridine instead of NH3 in 5. These synthesized compounds were characterized spectroscopically, and the singe-crystal structures of the Na3·18-crown-6 and K4·18-crown-6 adducts were determined. Furthermore, the reactions of Na3 and Na4 with cationic B-N chain compounds, [NH3BH2NH3]Cl and [NH3BH2NH2BH2NH3]Cl, could not form longer BCN-heterocyclic B-N chain. The solubility of metal hydrides, the ability for proton abstracting, the basicity of Lewis bases, and the chelate effect may influence these reactions even though the reaction mechanism is not fully understood.

Molecular detection and genetic characteristics of porcine circovirus 3 and porcine circovirus 4 in central China.

Porcine circoviruses (PCVs) are a significant cause of concern for swine health, with four genotypes currently recognized. Two of these, PCV3 and PCV4, have been detected in pigs across all age groups, in both healthy and diseased animals. These viruses have been associated with various clinical manifestations, including porcine dermatitis and nephropathy syndrome (PDNS) and respiratory and enteric signs. In this study, we detected PCV3 and PCV4 in central China between January 2022 and February 2023. We tested fecal swabs and tissue samples from growing-finishing and suckling pigs with or without respiratory and systemic manifestations and found the prevalence of PCV3 to be 15.15% (15/99) and that of PCV3/PCV4 coinfection to be 4.04% (4/99). This relatively low prevalence might be attributed to the fact that most of the clinical samples were collected from pigs exhibiting respiratory signs, with only a few samples having been obtained from pigs with diarrhea. In some cases, PCV2 was also detected, and the coinfection rates of PCV2/3, PCV2/4, and PCV2/3/4 were 6.06% (6/99), 5.05% (5/99), and 3.03% (3/99), respectively. The complete genomic sequences of four PCV3 and two PCV4 isolates were determined. All four of the PCV3 isolates were of subtype PCV3b, and the two PCV4 isolates were of subtype PCV4b. Two mutations (A24V and R27K) were found in antibody recognition domains of PCV3, suggesting that they might be associated with immune escape. This study provides valuable insights into the molecular epidemiology and evolution of PCV3 and PCV4 that will be useful in future investigations of genotyping, immunogenicity, and immune evasion strategies.

Ultraflat Graphene Oxide Membranes with Newton-Ring Prepared by Vortex Shear Field for Ion Sieving.

The wrinkles on graphene oxide (GO) membranes have unique properties; however, they interfere with the mass transfer of interlayer channels, posing a major challenge in the development of wrinkle-free GO membranes with smooth channels. In this study, the wrinkles on GO were flattened using vortex shear to tightly stack them into ultraflat GO membranes with Newton's ring interference pattern, causing hydrolysis of the lipid bonds in the wrinkles and an increase in the number of oxygen-containing groups. With increasing flatness, the interlayer spacing of the GO membranes decreased, improving the stability of the interlayer structure, the flow resistance of water through the ultraflat interlayer decreased, and the water flux increased 3-fold. Importantly, the selectivity for K+/Mg2+ reached approximately 379.17 in a real salt lake. A novel concept is proposed for the development of new membrane preparation methods. Our findings provide insights into the use of vortex shearing to flatten GO.

Two-dimensional photonic crystals as selective filters for thermophotovoltaic applications.

The optical properties and performance of the two-dimensional photonic crystal (2D PhC) filters at normal incidence were simulated, and the best geometric parameters were obtained with the help of a global optimization program. The honeycomb structure has better performance, including high in-band transmittance, high out-band reflectance, and low parasitic absorption. The power density performance and conversion efficiency can reach 80.6% and 62.5%. Furthermore, the deeper cavity structure and multi-layer structure were designed to improve the performance of the filter. The deeper one can reduce the influence of transmission diffraction, increases the power density performance and conversion efficiency. The multi-layer structure reduces the parasitic absorption significantly and increases the conversion efficiency to 65.5%. These filters have both high efficiency and high power density, avoid the challenge of high-temperature stability faced by emitters, also easier and cheaper to fabricate compared to the 2D PhC emitters. These results suggest that the 2D PhC filters can be used in thermophotovoltaic systems for long-duration missions to improve the conversion efficiency.

Syntheses, Structures, and Reactivities of N-Heterocyclic Carbene-Coordinated Aminoborane Complexes.

Recent research has attracted considerable attention toward N-heterocyclic carbene-coordinated boranes (NHC-borane) and their B-substituted derivatives because of their unique characteristics. In the present work, we focused on the syntheses, structures, and reactivities of such types of amine complexes, [NHC·BH2NH3]X ((NHC = IPr (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) and IMe (1,3-dimethylimidazol-2-ylidene); X = Cl, I, OTf). We have developed a synthetic method to access NHC·BH2NH2 through the reaction of NaH with [IPr·BH2NH3]I, which was synthesized by the reaction of IPr·BH2I with NH3. As a Lewis base, NHC·BH2NH2 could further react with HCl or HOTf to produce the corresponding salts of [IPr·BH2NH3]+. IPr·BH2NH2BH2X (X = Cl, I) were synthesized by the reaction of HCl/I2 with IPr·BH2NH2BH3 and then converted to [IPr·BH2NH2BH2·IPr]X (X = Cl, I) by reacting with IPr. The IMe-coordinated boranes reacted quite similarly. The preliminary results revealed that the introduction of the NHC molecule has a considerable impact on the solubility and reactivities of aminoboranes.

Detection and genetic analysis of porcine circovirus-like virus in pigs with diarrhea between 2016 and 2021 in Henan and Shanxi provinces of China.

Porcine circovirus-like virus (PCLV) is a recently discovered virus that may be associated with diarrhea in pigs. To investigate the epidemic profile and genetic characteristics of this virus, 175 clinical samples (141 intestinal samples, 17 blood samples, and 17 fecal samples) were collected from diseased piglets during outbreaks of diarrhea from 33 pig farms in 19 cities of Henan and Shanxi provinces of China between 2016 and 2021 and were screened by PCR for the presence of PCLV. The results showed that the positive rate for PCLV was 32% (56/175) at the sample level, 60.6% (20/33) at the farm level, and 57.9% (11/19) at the city level, which varied from 5.88% to 44.12% between 2016 and 2021. It was also found that PCLV occurred in coinfections with porcine circovirus type 2 (PCV2), PCV3, PCV4, porcine epidemic diarrhea virus, and porcine reproductive and respiratory syndrome virus, but no nucleic acids were detected for transmissible gastroenteritis virus, porcine deltacoronavirus, or porcine rotavirus in piglets with diarrhea. Notably, PCLV was detected in 13 diarrheal piglets from four different farms that were negative for the other porcine viruses. These findings suggest that PCLV may be associated with porcine diarrhea and that it has been circulating in piglets in Henan and Shanxi provinces of China. In addition, the complete genomes of 13 PCLV strains were sequenced and found to share 35.4%-91.0% nucleotide sequence identity with sequences available in the GenBank database. Phylogenetic analysis based on Rep amino acid sequences revealed that the 13 PCLV strains from this study clustered in group 1 and were closely related to eight Chinese PCLV strains, Bo-Circo-like virus CH, American strains 21 and 22, and Hungarian strains 288_4 and 302_4, but they differed genetically from seven other foreign PCLV strains. The whole genome and rep gene of 13 PCLV strains in this study were 72.2%-82% and 83.8%-89.7% identical, respectively, to those of Bo-Circo-like virus strain CH, indicating that PCLV is a novel virus in pigs that may be involved in cross-species transmission. Evidence of a recombination event was found in the rep region of the 13 PCLV strains sequenced. This study enriches the epidemiological data on PCLV infection in pigs in China and lays a foundation for further study on the pathogenesis of PCLV.

Simultaneous detection and phylogenetic analysis of porcine epidemic diarrhea virus and porcine circovirus 4 in Henan province, China.

Porcine circovirus 4 (PCV4) is a recently discovered circovirus that was first reported in 2019 in several pigs in Hunan province of China and has also been identified in pigs infected with porcine epidemic diarrhea virus (PEDV). To further investigate the coinfection and genetic diversity of these two viruses, 65 clinical samples (including feces and intestinal tissues) were collected from diseased piglets on 19 large-scale pig farms in Henan province of China, and a duplex SYBR Green I-based quantitative real-time polymerase chain reaction (qPCR) assay was developed for detecting PEDV and PCV4 simultaneously. The results showed that the limit of detection was 55.2 copies/µL and 44.1 copies/µL for PEDV and PCV4, respectively. The detection rate for PEDV and PCV4 was 40% (26/65) and 38% (25/65), respectively, and the coinfection rate for the two viruses was 34% (22/65). Subsequently, the full-length spike (S) gene of eight PEDV strains and a portion of the genome containing the capsid (Cap) gene of three PCV4 strains were sequenced and analyzed. Phylogenetic analysis showed that all of the PEDV strains from the present study clustered in the G2a subgroup and were closely related to most of the PEDV reference strains from China from 2011 to 2021, but they differed genetically from a vaccine strain (CV777), a Korean strain (virulent DR1), and two Chinese strains (SD-M and LZC). It is noteworthy that two PEDV strains (HEXX-24 and HNXX-24XIA) were identified in one sample, and the HNXX-24XIA strain had a large deletion at amino acids 31-229 of the S protein. Moreover, a recombination event was observed in strain HEXX-24. Phylogenetic analysis based on the amino acid sequence of the PCV4 Cap protein revealed that PCV4 strains were divided into three genotypes: PCV4a1, PCV4a2, and PCV4b. Three strains in the present study belonged to PCV4a1, and they had a high degree of sequence similarity (>98% identity) to other PCV4 reference strains. This study not only provides technical support for field investigation of PEDV and PCV4 coinfection but also provides data for their prevention and control.

Smart Wearable Systems for Health Monitoring.

Smart wearable systems for health monitoring are highly desired in personal wisdom medicine and telemedicine. These systems make the detecting, monitoring, and recording of biosignals portable, long-term, and comfortable. The development and optimization of wearable health-monitoring systems have focused on advanced materials and system integration, and the number of high-performance wearable systems has been gradually increasing in recent years. However, there are still many challenges in these fields, such as balancing the trade-off between flexibility/stretchability, sensing performance, and the robustness of systems. For this reason, more evolution is required to promote the development of wearable health-monitoring systems. In this regard, this review summarizes some representative achievements and recent progress of wearable systems for health monitoring. Meanwhile, a strategy overview is presented about selecting materials, integrating systems, and monitoring biosignals. The next generation of wearable systems for accurate, portable, continuous, and long-term health monitoring will offer more opportunities for disease diagnosis and treatment.

Wound healing rates and wound problems of conventional circumcision compared with ring circumcision: A meta-analysis.

A meta-analysis investigation was executed to measure the wound healing rates (WHRs) and wound problems (WPs) of conventional circumcision (CC) compared with ring circumcision (RC). A comprehensive literature investigation till March 2023 was applied and 2347 interrelated investigations were reviewed. The 16 chosen investigations enclosed 25 838 individuals, with circumcision, were in the chosen investigations' starting point, 3252 of them were RC, and 2586 were CC. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were used to compute the value of the WHRs and WPs of CC compared with RC by the dichotomous or continuous approaches and a fixed or random model. RC had a significantly lower wound infection rate (WIR) (OR, 0.58; 95% CI, 0.37-0.91, P = .002) and wound bleeding rate (WBR) (OR, 0.22; 95% CI, 0.12-0.42, P < .001) compared with those with CC. However, RC and CC had no significant difference in WHR (OR, 2.18; 95% CI, -0.73 to 5.09, P = .14), wound edema rate (WER) (OR, 1.11; 95% CI, 0.92-1.33, P = .28), and wound dehiscence rate (WDR) (OR, 0.98; 95% CI, 0.60-1.58, P = .93). RC had significantly lower WIR, and WBR, however, no significant difference in WHR, WER, and WDR compared with those with CC. However, care must be exercised when dealing with its values because of the low sample size of some of the nominated investigations for the meta-analysis.

Detection and genetic characteristics of porcine circovirus type 2 and 3 in Henan province of China.

PCV2 is one of the most economically important viral agents in swine worldwide. Recently, PCV3 has been frequently reported, and the co-infection of PCV2 and PCV3 is common in China. In order to explore the distribution, epidemiology and genetic diversity of PCV2 and PCV3, a total of 1,760 clinical tissue samples were randomly collected from 18 different regions in Henan province of China from October 2018 to September 2019 and screened for the presence of PCV2 and PCV3 by a duplex real-time PCR assay. The results showed that the positive rates of PCV2 and PCV3 were 72.90% and 5.17% respectively, and the co-infection rate of the two viruses was 3.64%. PCV2 and PCV3 are prevalent all year round. The prevalence of PCV2 in diseased pigs was 83.98%, higher than that in slaughterhouse pigs, while the prevalence of PCV3 in diseased pigs was 2.16%, slightly lower than that in slaughterhouse pigs. Furthermore, the complete genomes of 14 PCV2 and 3 PCV3 strains were obtained, among which 1 belonged to PCV2a, 5 belonged to PCV2b and 8 belonged to PCV2d. A new variant strain (XX2) might escape the host immune system. The phylogenetic analysis of PCV3 showed high nucleotide identity (>98%) between sequences obtained in this study and reference sequences. The results of this study might enrich the epidemiological data of PCV2 and PCV3 in Henan province and provide reference information for the comprehensive prevention and control of PCVAD.

Synthesis, Formation Mechanism, and Structure of K[BH3S(CH3)BH3] and Its Application in Preparation of KB3H8.

The design, synthesis, and applications of new boranes are eternal topics in boron chemistry. A new bis(borane)alkanethiolate salt, K[BH3S(CH3)BH3], was synthesized in high yield by the reaction of K with (CH3)2S·BH3 at room temperature. The formation mechanism was elucidated based on experimental and theoretical studies. The single-crystal structure of the K[BH3S(CH3)BH3]·18-crown-6 adduct was determined in which the B-S-B bonding information of K[BH3S(CH3)BH3] was illustrated for the first time. Using K[BH3S(CH3)BH3] as a starting material, KB3H8 was successfully synthesized.

Facile Synthetic Method of Na[BH3(NH2BH2)2H] Based on the Reactions of Sodium Amidoborane (NaNH2BH3) with NiBr2 or CoCl2.

The reactions of sodium amidoborane (NaNH2BH3) with NiBr2 have been investigated, and the results showed that black precipitate 1 including the NiBNHx composites could be obtained. From the aqueous solution of the precipitate 1, the hydrolysis product Ni-B (2) was isolated and characterized. Both the in situ formed precipitate 1 and the hydrolysis product 2 can catalyze the formation of Na[BH3(NH2BH2)2H]. CoCl2 showed comparable performance with NiBr2. Based on these results, a facile method for the synthesis of Na[BH3(NH2BH2)2H] has been developed. This work provides insights into studying experimental methods for the synthesis of long B/N chain complexes and developing boron and nitrogen chemistry.

Improved Methods for the Synthesis of KB3H8, NH3B3H7, and N-Alkyl Analogues of NH3B3H7.

Improved methods for the synthesis of KB3H8, NH3B3H7, and N-alkyl analogues of NH3B3H7 have been developed based on previous works. KB3H8 was synthesized by the reaction of metallic potassium (K) with borane dimethyl sulfide ((CH3)2S·BH3) with high yield and atom-economy. In the preparation of NH3B3H7 and its N-alkyl analogues, KB3H8 served as a starting material and was converted to THF·B3H7 first through reactions with HCl diethyl ether solution or oxidation agent CoCl2. Then, the formed THF·B3H7 in situ reacted with the corresponding ammonia or amines to form the amine borane final products. This work paves an alternative way for preparing organic-inorganic hybrid materials containing B, N, and C atoms.

Correction: Visible-light-mediated borylation of aryl and alkyl halides with a palladium complex.

Correction for 'Visible-light-mediated borylation of aryl and alkyl halides with a palladium complex' by Jia-Hui Zhao, et al., Org. Biomol. Chem., 2020, 18, 4390-4394, DOI: 10.1039/D0OB00028K.

Visible-light-mediated borylation of aryl and alkyl halides with a palladium complex.

Palladium catalyzed visible-light-mediated borylation of inactivated aryl and alkyl halides is reported; the method provided high yields and excellent functional group compatibility. Furthermore, arylsilicates were synthesized selectively using dimethylphenylsilyl boronic ester via changing the reaction conditions. Finally, the possible reaction mechanism is determined through fluorescence quenching and turn on/off experiments.

Screening and identification of serum biomarkers of osteoarticular tuberculosis based on mass spectrometry.

BACKGROUND: In view of the current difficulty of clinically diagnosing osteoarticular tuberculosis, our aim was to use mass spectrometry to establish diagnostic models and to screen and identify serum proteins which could serve as potential diagnostic biomarkers for early detection of osteoarticular tuberculosis. METHODS: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to select an osteoarticular tuberculosis-specific serum peptide profile and establish diagnostic models. Further, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify potential serum biomarkers that could be used for auxiliary diagnosis of osteoarticular tuberculosis, and then clinical serum samples were used to verify these biomarkers by enzyme-linked immunosorbent assay (ELISA). RESULTS: We established four diagnostic models that can distinguish osteoarticular tuberculosis from rheumatoid arthritis, ankylosing spondylitis, osteoarticular infections, and healthy adults. The models were osteoarticular tuberculosis-rheumatoid arthritis, osteoarticular tuberculosis-ankylosing spondylitis, osteoarticular tuberculosis-osteoarticular infections, and osteoarticular tuberculosis-healthy adult, and their accuracy was 76.78%, 79.02%, 83.77%, and 88.16%, respectively. Next, we selected and identified 18 proteins, including complement factor H-related protein 1 (CFHR1) and complement factor H-related protein 2 (CFHR2), which were upregulated in the tuberculosis group only. CONCLUSIONS: We successfully established four diagnostic models involving osteoarticular tuberculosis, rheumatoid arthritis, ankylosing spondylitis, osteoarticular infections, and healthy adults. Furthermore, we found that CFHR1 and CFHR2 may be two valuable auxiliary diagnostic indicators for osteoarticular tuberculosis. These results provide reference values for rapid and accurate diagnosis of osteoarticular tuberculosis.

Influence of nanopore density on ethylene/acetylene separation by monolayer graphene.

The use of nanoporous graphene for separation has attracted increasing interest over the past few years. Nanopore size, temperature, pressure and functionalization are vital for selectivity, but the influence of nanopore density is not known. Thus, we designed a monolayer nanoporous graphene membrane and revealed the influence of nanopore density on its ethylene/acetylene separation performance by employing molecular dynamics (MD) simulations. Our results indicate that an optimal nanopore density exists for permeation flux and selectivity. The MD simulation results were confirmed by density functional theory (DFT) and the kinetic theory of gases. The interactions between ethylene/acetylene and nanopores were also investigated, and van der Waals (vdW) interactions with slight steric repulsion were detected.

Facile Synthesis of Unsolvated Alkali Metal Octahydrotriborate Salts MB3 H8 (M=K, Rb, and Cs), Mechanisms of Formation, and the Crystal Structure of KB3 H8.

A facile synthesis of heavy alkali metal octahydrotriborates (MB3 H8 ; M=K, Rb, and Cs) has been developed. It is simply based on reactions of the pure alkali metals with THF⋅BH3 , does not require the use of electron carriers or the addition of other reaction media such as mercury, silica gel, or inert salts as for previous procedures, and delivers the desired products at room temperature in very high yields. However, no reactions were observed when pure Li or Na was used. The reaction mechanisms for the heavy alkali metals were investigated both experimentally and computationally. The low sublimation energies of K, Rb, and Cs were found to be key for initiation of the reactions. The syntheses can be carried out at room temperature because all of the elementary reaction steps have low energy barriers, whereas reactions of LiBH4 /NaBH4 with THF⋅BH3 have to be carried out under reflux. The high stability and solubility of KB3 H8 were examined, and a crystal structure thereof was obtained for the first time.

Elucidation of the Formation Mechanisms of the Octahydrotriborate Anion (B3H8-) through the Nucleophilicity of the B-H Bond.

Boron compounds are well-known electrophiles. Much less known are their nucleophilic properties. By recognition of the nucleophilicity of the B-H bond, the formation mechanism of octahydrotriborate (B3H8-) was elucidated on the bases of both experimental and computational investigations. Two possible routes from the reaction of BH4- and THF·BH3 to B3H8- were proposed, both involving the B2H6 and BH4- intermediates. The two pathways consist of a set of complicated intermediates, which can convert to each other reversibly at room temperature and can be represented by a reaction circle. Only under reflux can the B2H6 and BH4- intermediates be converted to B2H5- and BH3(H2) via a high energy barrier, from which H2 elimination occurs to yield the B3H8- final product. The formation of B2H6 from THF·BH3 by nucleophilic substitution of the B-H bond was captured and identified, and the reaction of B2H6 with BH4- to produce B3H8- was confirmed experimentally. On the bases of the formation mechanisms of B3H8-, we have developed a facile synthetic method for MB3H8 (M = Li and Na) in high yields by directly reacting the corresponding MBH4 salts with THF·BH3. In the new synthetic method for MB3H8, no electron carriers are needed, allowing convenient preparation of MB3H8 in large scales and paving the way for their wide applications.

Collisions of noble gas atoms with graphene and a graphene nanodome.

The collisions of noble gas atoms with graphene and a graphene nanodome were investigated by employing first principles molecular dynamics calculations. By analyzing the electron-related properties of the collision process, the atom dynamics and the deformation of the graphene/nanodome, our results show a difference between the elastic properties of the nanodome and graphene. Generally, the nanodome can more easily revert to its initial conformation. The final kinetic energy, Ef, of the atom that collides with the nanodome is larger than the Ef of the atom that collides with graphene. In addition, the relationship between the initial kinetic energy of the atom, Ek0, and its corresponding proportion of energy loss, χ, is linear (except for the Kr atom). Our research will probably contribute to the investigation of the 2D materials' mechanical properties and their surface morphology. Moreover, due to its novel mechanical properties, the graphene nanodome is an extraordinary nano-architecture which can be employed to protect nano-devices from damage and injury.