Comorbidity increases the risk of pulmonary tuberculosis: a nested case-control study using multi-source big data.

BACKGROUND: Some medical conditions may increase the risk of developing pulmonary tuberculosis (PTB); however, no systematic study on PTB-associated comorbidities and comorbidity clusters has been undertaken. METHODS: A nested case-control study was conducted from 2013 to 2017 using multi-source big data. We defined cases as patients with incident PTB, and we matched each case with four event-free controls using propensity score matching (PSM). Comorbidities diagnosed prior to PTB were defined with the International Classification of Diseases-10 (ICD-10). The longitudinal relationships between multimorbidity burden and PTB were analyzed using a generalized estimating equation. The associations between PTB and 30 comorbidities were examined using conditional logistic regression, and the comorbidity clusters were identified using network analysis. RESULTS: A total of 4265 cases and 17,060 controls were enrolled during the study period. A total of 849 (19.91%) cases and 1141 (6.69%) controls were multimorbid before the index date. Having 1, 2, and ≥ 3 comorbidities was associated with an increased risk of PTB (aOR 2.85-5.16). Fourteen out of thirty comorbidities were significantly associated with PTB (aOR 1.28-7.27), and the associations differed by sex and age. Network analysis identified three major clusters, mainly in the respiratory, circulatory, and endocrine/metabolic systems, in PTB cases. CONCLUSIONS: Certain comorbidities involving multiple systems may significantly increase the risk of PTB. Enhanced awareness and surveillance of comorbidity are warranted to ensure early prevention and timely control of PTB.

Two 3D Ln(III)-MOFs Based on Phosphineoxide Ligand: Synthesis, Structure Luminescent and Photocatalytic Properties.

Two new 3D metal-organic frameworks (MOFs) ZZUT1 and ZZUT2 were prepared through the reaction of tris-(4-carboxylphenyl) phosphineoxide (H3TPO) ligand with nitrate of neodymium and praseodymium by solvothermal method. The structure, fluorescence and photocatalytic properties of ZZUT1 and ZZUT2 were studied. The crystalline structure of two 3D Ln(III)-MOFs both exhibit triclinic system and P-1 space group. The results of fluorescence analysis showed that two 3D Ln(III)-MOFs could selectively recognize acetone molecule through the fluorescence quenching mechanism. Meanwhile, ZZUT1 and ZZUT2 showed good adsorption and degradation ability on organic dye methylene blue (MB) in photocatalytic condition, and the degradation efficiency can reach to more than 90%.

First Report of Anthracnose on Chili Pepper Caused by Colletotrichum sojae in Hebei Province, China.

China is the largest chili pepper producing country, and Hebei Province stands out as the forth with planting area at about 1500 km2 in China. Pepper (Capsicum annuum L.) is susceptible to Colletotrichum spp. infection during its growth, which seriously affects production yield and quality. In September 2020, widespread anthracnose was observed on pepper in Hebei (115.48° N, 38.77° E), China. Necrotic lesions on pepper fruits were suborbcular, sunken, with acervuli arranged in the middle of lesion (e-Xtra 1A). To perform fungal isolation, small tissue with 0.3 cm2 in size at the symptomatic tissue margin was surface disinfested with 75% ethanol for 10 s, and 0.1% HgCl2 for 40 s, then washed three times with sterile ddH2O. Fragments were placed on potato dextrose agar (PDA) amended with 100 mg·L-1 chloramphenicol and incubated at 28 ºC under darkness for 4 days. One of the strains of Colletotrichum spp., named HQY157, was purified by single-spore isolation, then used for morphological characterization, phylogenetic analysis, and pathogenicity tests. Colonies presented light grey aerial mycelium, occasionally mixed with gray-black strips, and the reverse was similar to the surface on PDA (e-Xtra 1B). Conidia were smooth-walled, aseptate, straight with obtuse to slightly rounded ends, 17.3-28.5 × 3.1-7.4 µm (n=50) (e-Xtra 1C). For molecular identification, the internal transcribed spacer (ITS) region, partial sequences of actin (ACT), ß-tublin (TUB), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and chitin synthase (CHS) were sequenced using the specific primers (Weir et al. 2012). Sequences were deposited in GenBank with the following accession numbers OM317600-OM317604. A Maximum-Likelihood phylogenetic tree was constructed, based on the concatenated sequences (ACT, CHS, GAPDH, TUB, and ITS) of HQY157 and other closely matching Colletotrichum species obtained from GenBank, by using MEGA-X. It showed that HQY157 was grouped with the C. sojae with bootstrap values of 100% (e-Xtra 2). To confirm the pathogenicity, surface-sterilized healthy pepper fruits and healthy fruits with wounds (deal with a sterile toothpick after surface-sterilized) were then inoculated with 2 µL of conidial suspension (106 conidia/mL). The fruits inoculated with 2 µL sterile distilled water were taken as negative controls. After inoculation, the fruits were kept in a plastic box with sterilized filter paper moistened with sterilized water, and maintained at 25°C in the dark. The experiment was repeated three times. Anthracnose symptoms were observed 7 days after inoculation on the wounded pepper fruits, whereas the unwounded and negative control fruits remained symptomless (e-Xtra 1D). Colletotrichum sojae was re-isolated from the infected pepper fruits and identified by morphological and molecular analysis, fulfilling Koch's postulates. Colletotrichum sojae occurs mainly on Fabaceae plants such as Glycine max, Medicago sativa, Phaseolus vulgaris, and Vigna unguiculata (Damm et al. 2019, Talhinhas and Baroncelli, 2021), and Panax quinquefolium (Guan et al. 2021). To our knowledge, this is the first report of C. sojae causing anthracnose on pepper in China. This study provided crucial information for epidemiologic studies and appropriate control strategies for this chili pepper disease.

Microporous framework membranes for precise molecule/ion separations.

Microporous framework membranes such as metal-organic framework (MOF) membranes and covalent organic framework (COF) membranes are constructed by the controlled growth of small building blocks with large porosity and permanent well-defined micropore structures, which can overcome the ubiquitous tradeoff between membrane permeability and selectivity; they hold great promise for the enormous challenging separations in energy and environment fields. Therefore, microporous framework membranes are endowed with great expectations as next-generation membranes, and have evolved into a booming research field. Numerous novel membrane materials, versatile manipulation strategies of membrane structures, and fascinating applications have erupted in the last five years. First, this review summarizes and categorizes the microporous framework membranes with pore sizes lower than 2 nm based on their chemistry: inorganic microporous framework membranes, organic-inorganic microporous framework membranes, and organic microporous framework membranes, where the chemistry, fabrications, and differences among these membranes have been highlighted. Special attention is paid to the membrane structures and their corresponding modifications, including pore architecture, intercrystalline grain boundary, as well as their diverse control strategies. Then, the separation mechanisms of membranes are covered, such as diffusion-selectivity separation, adsorption-selectivity separation, and synergetic adsorption-diffusion-selectivity separation. Meanwhile, intricate membrane design to realize synergistic separation and some emerging mechanisms are highlighted. Finally, the applications of microporous framework membranes for precise gas separation, liquid molecule separation, and ion sieving are summarized. The remaining challenges and future perspectives in this field are discussed. This timely review may provide genuine guidance on the manipulation of membrane structures and inspire creative designs of novel membranes, promoting the sustainable development and steadily increasing prosperity of this field.

Kirkpatrick's evaluation of the effect of a nursing innovation team training for clinical nurses.

AIM: This study aims to design a 100-h training programme for nursing innovation teams and to evaluate the effect of this training programme using Kirkpatrick's model. BACKGROUND: The innovative capability of nurses is a powerful driver for the development of the nursing discipline, and it is currently at a low to medium level in China. Innovation competency development has become a research trend in nurses' in-service education, but only changes in nursing innovation behaviours before and after training have been evaluated. The cascading, continuous assessment tools are rarely used. METHODS: This is a quasi-experimental research design: pretest and posttest design. Totally, 61 clinical nurses from Hangzhou Hospital of Traditional Chinese Medicine were enrolled for innovation training. This innovation team training programme consisted of a 36-h theoretical training phase and a 64-h collaborative training phase. The four levels of Kirkpatrick's model, that is, reaction, learning, behaviour, and result, were applied for the evaluation together with questionnaires. RESULTS: At reaction level, the nurses' attendance was over 85% in two phases. The differences between nurse organizational innovation climate scores of tested nurses before and after training were statistically significant (t = -22.559, P < .001). At learning level, there were statistically significant differences between nurses' innovation self-efficacy scale scores of tested nurses before and after training (t = -16.832, P < .001). At behaviour level, the nursing innovation behaviour scale scores of tested nurses were significantly higher after training (t = -18.950, P < .001) than before the training. At result level, the clinical nurse innovation ability of tested nurses after the training were higher than before the training (t = -26.275, P < .001). The numbers of patent applications, granted patents, application for scientific research projects, sponsored scientific research projects, and papers published by team members after the training were larger than those before training (Z = -2.032, P = .042). CONCLUSION: Kirkpatrick's model can evaluate the effectiveness of nursing innovation training for clinical nurses. The nursing innovation training is beneficial to improve nurses' innovation capacity, organizational innovation climate and innovation self-efficacy, and nursing innovation behaviour and promote the output of research and innovation projects. IMPLICATIONS FOR NURSING MANAGEMENT: Managers can flexibly develop training modules with regional characteristics based on this programme to effectively improve the innovation ability of clinical nurses, thus meeting the urgent demand for innovative nursing talents and the rapid development of nursing disciplines.

[Comparison of wall filter algorithms for ultrasonic microvascular imaging].

The design of wall filter in ultrasonic microvascular imaging directly affects the resolution of blood flow imaging. We compared the traditional polynomial regression wall filter algorithm and two algorithms based on singular value decomposition (SVD), Full-SVD algorithm and RS-RSVD algorithm (random sampling based on random singular value decomposition) through experiments with simulated data and human renal entity data imaging experiments. The experimental results showed that the filtering effect of the traditional polynomial regression wall filter algorithm was limited, however, Full-SVD algorithm and RS-RSVD algorithm could better extract the micro blood flow signal from the tissue or noise signal. When RS-RSVD algorithm was randomly divided into 16 blocks, the signal-to-noise ratio was the same as that of Full-SVD algorithm, reduces the contrast-to-noise ratio by 2.05 dB, and reduces the execution time by 90.41%. RS-RSVD algorithm can improve the operation efficiency and is more conducive to the real-time imaging of high frame rate ultrasound microvessels.

Analogous Mixed Matrix Membranes with Self-Assembled Interface Pathways.

The implementation of mixed matrix membranes (MMMs) for sub-angstrom scale gas separations remains a grand challenge. Herein, a series of analogous mixed matrix membrane (AMMMs) were constructed via molecular-level hybridization by utilizing a reactive ionic liquid (RIL) as the continuous phase and graphene quantum dots (GQD) as nanofiller for sub-angstrom scale ethylene/ethane (0.416 nm/0.443 nm) separation. With a small number of GQDs (3.5 wt%) embedded in GQD/RIL AMMMs, ethylene permeability soared by 3.1-fold, and ethylene/ethane selectivity simultaneously boosted by nearly 60 % and reached up to 99.5, which outperformed most previously reported state-of-the-art membranes. Importantly, the interfacial pathway structure was visualized and their self-assembly mechanism was revealed, where the non-covalent interactions between RIL and GQDs induced the local arrangement of IL chains to self-assemble into plenty of compact and superfast interfacial pathways, contributing to the combination of superhigh permeability and selectivity.

Administration of tissue plasminogen activator without coagulation results in a Chinese population.

Routine coagulation test before intravenous tissue plasminogen activator (tPA) use increases the door to needle time (DNT). We sought to evaluate the safety of tPA use without coagulation results and its impact on prognosis. In our stroke registry, tPA was delivered with coagulation results from December 2015 to April 2016 and without coagulation results from May 2016 to December 2016. Differences of demographics, clinical characteristic, and prognosis between these two groups were analyzed. In addition, logistic regression analysis was conducted to identify predictors for DNT of over 60 min. A total of 201 stroke patients were included in the final analysis. Of these, 81 patients received tPA with coagulation results and 120 patients without coagulation results. Only one (0.8%) patient with abnormal coagulation results met the exclusion criteria of tPA use in patients without coagulation results. The difference of DNT between groups with (mean, 61.7 min) and without (mean, 41.9 min) coagulation results was significant (P = 0.00). The group without coagulation results had a higher rate of favorable 90-day outcome (74.2 vs 70.4%) and lower rates of symptomatic intracranial hemorrhage/nonintracranial hemorrhage (4.9 and 22.2% vs 1.7 and 19.2%) than the group with coagulation results did; these differences were not statistically significant. In multivariate analysis, only tPA use with coagulation results was the predictor for DNT of over 60 min (P = 0.0030, OR = 2.44, 95% CI 1.28-4.65). The present study suggests that tPA could be delivered safely without coagulation results in patients without suspected coagulopathy, and avoiding coagulation tests reduces significantly the DNT interval.

Minor Nonintracranial Hemorrhage and Poor Prognosis among Stroke Patients Undergoing Intravenous Thrombolysis.

BACKGROUND: Whether nonintracranial hemorrhage (NICH) associated with intravenous thrombolysis (IVT) is a predictor of intracranial hemorrhage (ICH) and poor prognosis is ambiguous. We sought to analyze the rate of NICH and the relationship between NICH and poor outcome in the ischemic stroke population undergoing IVT. METHODS: This is a single-center, hospital-based prospective study. All ischemic stroke patients undergoing IVT between December 2015 and November 2016 were included. NICH was defined according to the criteria of the Bleeding Academic Research Consortium (BARC). ICH associated with IVT was defined based on the European Cooperative Acute Stroke Study II definition. On the basis of the modified Rankin Scale (mRS), 90-day outcome was divided into favorable outcome (mRS score 0-1) versus unfavorable outcome (mRS score 2-6) and independency (mRS score 0-2) versus dependency and death (mRS score 3-6). RESULTS: A total of 212 patients undergoing IVT were included in the analysis. Forty-five NICH events were reported in 42 patients (19.8%). Older age was independently associated with NICH (P = .049, odds ratio [OR] = .97, 95% confidence interval [CI] .94-1.0). Neither NICH with BARC class 1 or higher (P = .56, OR = .61, 95% CI .11-3.24) nor NICH with BARC class 2 or higher (P = .87, OR = 1.19, 95% CI .14-10.23) was associated with ICH. NICH with BARC class 1 or higher was not associated with unfavorable outcome (P = .67, OR = 1.17, 95% CI .56-2.45) and dependence and death (P = .47, OR = .72, 95% CI .30-1.75), neither was NICH with BARC class 2 or higher (P = .97, OR = 1.02, 95% CI .46-2.27 and P = .30, OR = .59, 95% CI .22-1.62). CONCLUSIONS: NICH was common among ischemic stroke populations receiving IVT. NICH with BARC class 2 or lower was not associated with ICH and poor outcome.

p38α subtype is a potential target to inhibit eNOS activity and NO production in human endothelial cells.

Human endothelial nitric oxide synthase (eNOS) activity is important for maintaining blood pressure homeostasis and vascular integrity through nitric oxide (NO).The in vitro study aimed at investigating a role of p38α signaling in modulating NO production in human umbilical vein endothelial cell-12 (HUVEC-12). Consistent with the stimulation of lipopolysaccharide (LPS) or tumor necrosis factor (TNF)-α, the over-expression of p38α markedly down-regulated the eNOS promoter activity in HUVEC-12, which could be reversed by its negative mutant p38α (AF) or p38-specific inhibitor SB203580. Compared to the stimulation of LPS or TNF-α, p38α-targeting siRNA decreased the expressions of phosphorylated and non-phosphorylated p38α, and increased the promoter activity, an eNOS mRNA level and a phosphorylated eNOS protein expression with the enhancement of NO, which could be abrogated by the scrambled siRNA. The in situ eNOS protein expression in the cells treated by p38α-targeting siRNA was also higher than that of the control, following the corresponding attenuation of a p38 level, and mainly localized in the inner membrane and cytoplasm. These results indicate that the p38α subtype may be a potential target to down-regulate the eNOS activity and NO production in human endothelial cells.

On the nature of the transition state characterizing gated molecular encapsulations.

Gated molecular encapsulations, with baskets of type 1, are postulated to occur by the mechanism in which solvent molecule penetrates the inner space of 1, through one of its apertures, while the residing guest simultaneously departs the cavity. In the transition state of the exchange, three pyridine-based gates are proposed to assume an open position with both incoming solvent and departing guest molecules interacting with the concave surface of the host. The More O'Ferrall-Jencks diagram and linear free energy relationships (LFERs) suggest a more advanced departure of the guest when bigger solvents partake in the displacement.

Adaptive Skid-Steering Control Approach for Robots on Uncertain Inclined Planes with Redundant Load-Bearing Mobility.

Climbing manufacturing robots can create a revolutionary manufacturing paradigm for large and complex components, while the motion control of climbing manipulation-oriented robots (CMo-Rs) is still challenging considering anti-slippage problems. In this study, a CMo-R with full-scenery climbing capability and redundant load-bearing mobility is designed based on magnetic adsorption. A four-wheel kinematic model considering the slipping phenomenon is established. An adaptive kinematic control algorithm based on slip estimation using Lyapunov theory is designed for uncertain inclined planes. For comparison, the traditional PID-based algorithm without slip consideration is implemented as well. Numeric simulations are conducted to tackle the trajectory tracking problems for both circular and linear trajectories on the horizontal plane (HP), 50° inclined plane (50° IP), 60° inclined plane (60° IP), and vertical plane (VP). The results prove that our approach achieves better tracking accuracy. It demonstrated applicability in various climbing scenarios with uncertain inclined planes. The results of experiments also validate the feasibility, applicability, and stability of the proposed approach.

Epidemiological Features of Infectious Diseases in Children and Adolescents: A Population-Based Observational Study in Shandong Province, China, 2013-2017.

BACKGROUND: The arrival of the big-data era provides us with a chance to elaborate the spectrum and epidemiological characteristics of infectious diseases in children and adolescents aged 0-18 years in the pre-COVID-19 pandemic era. METHODS: We collected data on infectious diseases in 891,981 participants from the Cheeloo Lifespan Electronic Health Research Data-library. The incidence density of each infection was calculated and stratified by age and region. The annual percentage change (APC) in incidence was estimated by logarithmic linear regression. RESULTS: A total of 18,183 cases of 78 infections were diagnosed, with an overall incidence density of 626.33 per 100,000 person-years (PY). Of these, 6825 cases of 50 non-notifiable infectious diseases were identified. Children aged 1-3 years had the highest incidence of infections. The overall incidence revealed a significant increasing trend from 2013 to 2017 (APC = 36.9%, p < 0.05). Hand, foot, and mouth disease, pneumonia, and influenza were the three most common diseases. The incidence of pneumonia, rubella, scarlet fever, zoster, molluscum contagiosum, and syphilis increased significantly during the study period (all p < 0.05). Taian, Binzhou, and Weihai had the highest incidence of all other cities. The incidence of gastrointestinal infections increased markedly in the eastern coastal regions. CONCLUSIONS: More stress should be placed on a number of non-notifiable infectious diseases with a high burden and a significant increasing trend. Age-based and regional targeting efforts are needed to prevent and contain infectious diseases among children and adolescents.

Microbial-induced carbonate precipitation effectively prevents Pb2+ migration through the soil profile: Lab experiment and model simulation.

Due to the inappropriate disposal of waste materials containing lead (Pb) and irrigation with sewage containing Pb, the migration of Pb2+ within the soil profile has been extensively investigated. The conventional Pb2+ block method is challenging to implement due to its complex operational procedures and high construction costs. To address this issue, this study introduces the microbial-induced carbonate precipitation (MICP) technique as a novel approach to impede the migration of Pb2+ in the soil profile. Soil acclimatization with urea resulted in an increased proportion of urease-producing microorganisms, including Bacillus, Paenibacillus, and Planococcaceae, along with heightened expression of urea-hydrolyzing genes (UreA, UreB, UreC, and UreG). This indicates that urea-acclimatized soil (Soil-MICP) possesses the potential to induce carbonate precipitation. Batch Pb2+ fixation experiments confirmed that the fixation efficiency of Soil-MICP on Pb2+ exceeded that of soil without MICP, attributed to the MICP process within the Soil-MICP group. Dynamic migration experiments revealed that the MICP reaction transformed exchangeable lead into carbonate-bound Pb, effectively impeding Pb2+ migration in the soil profile. Additionally, the migration rate of Pb2+ in Soil-MICP was influenced by varying urea amounts, pH levels, and pore flow rates, leading to a slowdown in migration. The Two-site sorption model aptly described the Pb2+ migration process in the Soil-MICP column. This study aims to elucidate the MICP biomineralization process, uncover the in-situ blocking mechanism of MICP on lead in soil, investigate the impact of Pb on key genes involved in urease metabolism, enhance the comprehension of the chemical morphology of lead mineralization products, and provide a theoretical foundation for MICP technology in preventing the migration of Pb2+ in soil profiles.

An integrated data analysis reveals distribution, hosts, and pathogen diversity of Haemaphysalis concinna.

BACKGROUND: Haemaphysalis concinna, carrying multiple pathogens, has attracted increasing attention because of its expanded geographical range and significant role in disease transmission. This study aimed to identify the potential public health risks posed by H. concinna and H. concinna-associated pathogens. METHODS: A comprehensive database integrating a field survey, literature review, reference book, and relevant websites was developed. The geographical distribution of H. concinna and its associated pathogens was illustrated using ArcGIS. Meta-analysis was performed to estimate the prevalence of H. concinna-associated microbes. Phylogenetic and geographical methods were used to investigate the role of birds in the transmission of H. concinna-associated microbes. The potential global distribution of H. concinna was predicted by ecological niche modeling. RESULTS: Haemaphysalis concinna was distributed in 34 countries across the Eurasian continent, predominantly in China, Russia, and Central Europe. The tick species carried at least 40 human pathogens, including six species in the Anaplasmataceae family, five species of Babesia, four genospecies in the complex Borrelia burgdorferi sensu lato, ten species of spotted fever group rickettsiae, ten species of viruses, as well as Francisella, Coxiella, and other bacteria. Haemaphysalis concinna could parasitize 119 host species, with nearly half of them being birds, which played a crucial role in the long-distance transmission of tick-borne microbes. Our predictive modeling suggested that H. concinna could potentially survive in regions where the tick has never been previously recorded such as central North America, southern South America, southeast Oceania, and southern Africa. CONCLUSIONS: Our study revealed the wide distribution, broad host range, and pathogen diversity of H. concinna. Authorities, healthcare professionals, and the entire community should address the growing threat of H. concinna and associated pathogens. Tick monitoring and control, pathogen identification, diagnostic tools, and continuous research should be enhanced.

The entrapment of chiral guests with gated baskets: can a kinetic discrimination of enantiomers be governed through gating?

The capacity of gated hosts for controlling a kinetic discrimination between stereoisomers is yet to be understood. To conduct corresponding studies, however, one needs to develop chiral, but modular and gated hosts. Accordingly, we used computational (RI-BP86/TZVP//RI-BP86/SV(P)) and experimental (NMR/CD/UV/Vis spectroscopy) methods to examine the transfer of chirality in gated baskets. We found that placing stereocenters of the same kind at the rim (R(1) =CH3, so-called bottom) and/or top amide positions (R(2) =sec-butyl) would direct the helical arrangement of the gates into a P or M propeller-like orientation. With the assistance of (1)H NMR spectroscopy, we quantified the intrinsic (thermodynamic) and constrictive (kinetic) binding affinities of (R)- and (S)-1,2-dibromopropane 5 toward baskets (S3b/P)-2, (S3t/M)-3, and (S3bt/P)-4. Interestingly, each basket has a low ( ≤1.3 kcal mol(-1)), but comparable (de<10%) affinity for entrapping enantiomeric (R/S)-5. In terms of the kinetics, basket (S3b/P)-2, with a set of S stereocenters at the bottom and P arrangement of the gates, would capture (R)-5 at a faster rate (kin(R)/kin(S) =2.0±0.2). Basket (S3t/M)-3, with a set of S centers at the top and M arrangement of the gates, however, trapped (S)-5 at a faster rate (kin(R)/kin(S) =0.30±0.05). In light of these findings, basket (S3bt/P)-4, with a set of S stereocenters installed at both top and bottom sites along with a P disposition of the gates, was found to have a lower ability to differentiate between enantiomeric (R/S)-5 (kin(R)/kin(S) =0.8). Evidently, the two sets of stereocenters in this "hybrid" host acted concurrently, each with the opposite effect on the entrapment kinetics. Gated baskets are hereby established to be a prototype for quantifying the kinetic discrimination of enantiomers through gating and elucidating the electronic/steric effects on the process.

On the role of guests in enforcing the mechanism of action of gated baskets.

We designed and prepared a spacious and gated basket of type 2 (V = 318 Å(3)) in ten synthetic steps. With the assistance of (1)H NMR spectroscopy, we found that the pyridine gates at the rim of 2 form a seam of N-H∙∙∙N hydrogen bonds, thereby adopting right- (P) and left-handed (M) helical arrangements. The recognition characteristics of the smaller basket 1 (V = 226 Å(3)) and the larger 2 for various solvents as guests were quantified by (1)H NMR spectroscopy in CD2Cl2 (61 Å(3)), CDCl3 (75 Å(3)), CFCl3 (81 Å(3)) and CCl4 (89 Å(3)); the apparent guest binding equilibria Ka were found to be inversely proportional to the affinity of bulk solvents KS for populating each host. The rate of the P/M racemization (krac, s(-1)) was, for both 1 and 2, studied in all four solvents using dynamic NMR spectroscopy. From these experiments, two isokinetic relationships (ΔS++P/M vs. ΔH++P/M) were identified with each one corresponding to a different mechanism of P/M racemization. A computational study (B3LYP/6-31+G**//PM6) of 1 and 2 in the gas phase indicates two competing racemization pathways: (a) RM1-2 describes a pivoting of a single gate followed by the rotation of the remaining two gates, while (b) RM3 depicts simultaneous (geared) rotation of all three gates. The racemization of the larger basket 2, in all four solvents (packing coefficient, PC = 0.19-0.28), conformed to one isokinetic relationship, which also coincided with the operation of the smaller basket 1 in CD2Cl2 (PC = 0.27). However, in CDCl3, CFCl3 and CCl4 (PC = 0.33-0.39), the mode of action of 1 appears to correlate with a different isokinetic relationship. Thus, we propose that the population of the basket's inner space (PC) determines the mechanism of P/M racemization. When PC < 0.3, the mechanism of operation is RM1-2, whereas, a greater packing, represented when PC > 0.3, enforces the geared RM3 mechanistic alternative.

Numerical Prediction of Microstructure Evolution of Small-Diameter Stainless Steel Balls during Cold Skew Rolling.

The wear resistance and hardness of stainless steel (SS) balls formed by cold skew rolling are effectively improved due to the change in internal microstructure. In this study, based on the deformation mechanism of 316L stainless steel, a physical mechanism-based constitutive model was established and implemented in a subroutine of Simufact to investigate the microstructure evolution of 316L SS balls during the cold skew rolling process. The evolution of equivalent strain, stress, dislocation density, grain size, and martensite content was studied via simulation during the steel balls' cold skew rolling process. The corresponding skew rolling experiments of steel balls were carried out to verify the accuracy of the finite element (FE) model results. The results showed that the macro dimensional deviation of steel balls fluctuates less, and the microstructure evolution agrees well with the simulation results, which proves that the established FE model has high credibility. It shows that the FE model, coupled with multiple deformation mechanisms, provides a good prediction of the macro dimensions and internal microstructure evolution of small-diameter steel balls during cold skew rolling.

Piezoelectricity-modulated optical recombination dynamics of monolayer-MoS2/GaN-film heterostructures.

Dynamic manipulation of optoelectronic responses by mechanical stimuli is promising for developing wearable electronics and human-machine interfacing. Although 2D-3D hybrid heterostructures can bring advancements in optoelectronics, their dynamic optical responses to external strains remain rarely studied. Here, we demonstrate the strain-tuned recombination dynamics of monolayer-MoS2 and thin-film-GaN heterostructures. We find that optical excitons in the heterostructures, apart from trions, can be markedly modulated by strains. We argue that MoS2 piezoelectric dipoles across the interfaces lead to curved band diagrams, in which optical excitons dissociate into spatially separated quasi-particles and concurrently relocate to the maxima of valence bands and the minima of conduction bands. With the increase in tensile strains, the photoluminescence (PL) intensity of the heterostructures shows quenched responses. Noticeably, the change in PL spectra strongly depends on the directions of the applied strains because of the lateral piezoelectric periodicity of MoS2 flakes. This work not only helps in understanding the underlying physics of the decreased PL intensities upon applying strains but also demonstrates a feasible way (i.e., strains) to manipulate the PL efficiency of 2D-material-based optoelectronics.

[Research Progress on the Remediation Technology of Herbicide Contamination in Agricultural Soils].

Asthe most-used pesticides in the agricultural production process, herbicides are mainly applied to protect crops from weeds. However, with the increased global demand for food, the dosage of herbicides is rising annually, and the efficacy of herbicides is getting stronger, which can cause some environmental issues including the accumulation, migration and transformation, and toxic effects of herbicides in agricultural soils. According to the characteristics of herbicide contamination and regional agricultural production, developing green and low-carbon technologies to reduce the ecological risks of herbicides to the soil-crop systems is a current concern in the ecological environment field. In this paper, relevant studies in recent years on herbicide pollution management in agricultural soils were identified and reviewed, the research progress and application cases of remediation technologies for herbicide pollution was analyzed and demonstrated, and future research and development tendency regarding the remediation of herbicides pollution was also prospected. Current remediation technologies for herbicides mainly include bioremediation technologies (e.g., microbial remediation, enzyme remediation, and phytoremediation), adsorption, and immobilization technologies (e.g., biochar-based materials). The bioremediation technologieswere rather mature and had been applied to the herbicide-contaminated soil in fields. Additionally, many successful bioremediation cases have been reported. Moreover, in order to enhance the remediation effect on herbicide pollution in agriculture soils, remediation technologies have been gradually developed from a single model to a coupled model with physical,chemical, and biological technology, which can maximize the synergy of the multi-technology application.