Preparation and application of alkali-activated cementitious materials in solidification/stabilization of chromite ore processing residue.

Chromite ore processing residue (COPR) is a typical hazardous waste, which contains Cr(vi) and poses a great threat to the ecological environment and human health. In this study, solidification/stabilization (S/S) of COPR was carried out by using blast furnace slag (BFS) and fly ash (FA) to prepare alkali-activated cementitious materials (AACM). The influence of different factors (water glass modulus, liquid-solid ratio, alkali-solid content and curing temperature) on compressive strength was investigated by single-factor experiment. Additionally, solidification effect of AACM was determined according to the compressive strength and the leaching concentration of chromium (Cr(vi) and total Cr). According to the optimal conditions of the single-factor experiment, the highest compressive strength of 147.6 MPa was obtained after using the water glass modulus 1.0, liquid-solid ratio 0.28, alkali-solid content 8%, curing temperature 45 °C. The COPR was solidified in the AACM sample having highest compressive strength. The solidified body still has a good mechanical property (38.2 MPa) with 60% addition COPR. According to leaching tests, the leaching of Cr(vi) and total Cr of solidified body with 50% COPR was far lower than the limit value, which met the purpose of construction and landfill disposal. X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis proved that heavy metal chromium was solidified in AACM by physical and chemical means.

Filtration performance of biofilm membrane bioreactor: Fouling control by threshold flux operation.

Membrane fouling is the major factor that restricts the furtherly widespread use of membrane bioreactor (MBR). As a new generation of MBR, biofilm membrane bioreactor (BF-MBR) demonstrates high treatment efficiency and low sludge growth rate, however the filtration performance improvement and membrane fouling control are still the challenges for its further development. This work investigated the filtration performance using resistance in series model and membrane fouling control via threshold flux for BF-MBR. At first, the flux behavior and filtration resistance under various operating conditions, including agitation speed, membrane and TMP, were explored by resistance in series model. Because of the desirable anti-fouling capacity, UP100 and UP030 had the high threshold flux (100 and 90 L m-2 h-1) and low irreversible fouling resistance (1 and 1.3 × 10-10 m-1). Higher shear stress produced by higher agitation speed could reduce membrane fouling, while greatly promote the threshold flux (138 L m-2 h-1) and membrane cleaning efficiency (96%). Moreover, increasing shear stress or selecting membrane with large pore size could decrease the fouling rate and raise the threshold flux. As for TMP, high TMP reduced the removal rate for organic and nutrient, and enhanced the irreversible fouling. Besides, the aerobic-BF-MBR (101 L m-2 h-1 and 1.3 × 10-10 m-1) with lower foulant concentration had a better filtration performance than anoxic-BF-MBR (90 L m-2 h-1 and 1.5 × 10-10 m-1). Additionally, the long-term tests with 10 cycles were conducted to evaluate the industrial application value of BF-MBR (45-58 L m-2 h-1). This work provides the technical support for sustainable filtration performance of BF-MBR.

Development of a duplex droplet digital PCR assay for the detection of Burkholderia cepacia complex and Stenotrophomonas maltophilia in bloodstream infections.

Burkholderia cepacia complex (BCC) and Stenotrophomonas maltophilia are nosocomial pathogens that cause various infections and exhibit high resistance to multiple antimicrobial agents. In this study, we aimed to develop a duplex droplet digital PCR (ddPCR) assay for detecting BCC and S. maltophilia in bloodstream infections. We optimized the experimental conditions by setting the annealing temperature to 51°C and determining the optimal concentrations of primers and probes, as well as the thermal cycle numbers. The feasibility of the duplex ddPCR reaction system with the optimal conditions was established and verified through parallel reactions with reference strains of BCC and S. maltophilia. The specificity of the assay, tested with 33 reference strains, was found to be 100%. The duplex ddPCR assay demonstrated good repeatability and could detect as low as 5.35 copies/reaction of BCC and 7.67 copies/reaction of S. maltophilia. This level of sensitivity was consistent in the simulated blood and blood bottle samples. We compared nucleic acid extraction methods and found that the Chelex-100 boiling method and kit extraction method exhibited similar detection sensitivity, suggesting the potential application of the Chelex-100 boiling method in the ddPCR assay. In the clinical samples, the duplex ddPCR assay accurately detected BCC and S. maltophilia in 58 cases. In conclusion, our study successfully developed a duplex ddPCR assay that provides accurate and convenient detection of BCC and S. maltophilia in bloodstream infections.IMPORTANCEBurkholderia cepacia complex (BCC) and Stenotrophomonas maltophilia are implicated in a wide range of infections, including bloodstream infections (BSIs), pneumonia, and meningitis, and often exhibit high intrinsic resistance to multiple antimicrobial agents, limiting therapeutic options. The gold standard for diagnosing bloodstream infections remains blood culture. However, current blood culture detection and positivity rates do not meet the "rapid diagnosis" required for the diagnosis and treatment of critically ill patients with BSIs. The digital droplet PCR (ddPCR) method is a potentially more powerful tool in the diagnosis of BSIs compared to other molecular methods due to its greater sensitivity, specificity, accuracy, and reproducibility. In this study, a duplex ddPCR assay for the detection of BCC and S. maltophilia in BSIs was developed.

Cross-modality interaction for few-shot multispectral object detection with semantic knowledge.

Multispectral object detection (MOD), which incorporates additional information from thermal images into object detection (OD) to robustly cope with complex illumination conditions, has garnered significant attention. However, existing MOD methods always demand a considerable amount of annotated data for training. Inspired by the concept of few-shot learning, we propose a novel task called few-shot multispectral object detection (FSMOD) that aims to accomplish MOD using only a few annotated data from each category. Specifically, we first design a cross-modality interaction (CMI) module, which leverages different attention mechanisms to interact with the information from visible and thermal modalities during backbone feature extraction. With the guidance of interaction process, the detector is able to extract modality-specific backbone features with better discrimination. To improve the few-shot learning ability of the detector, we also design a semantic prototype metric (SPM) loss that integrates semantic knowledge, i.e., word embeddings, into the optimization process of embedding space. Semantic knowledge provides stable category representation when visual information is insufficient. Extensive experiments on the customized FSMOD dataset demonstrate that the proposed method achieves state-of-the-art performance.

Research on data-driven low-sampling-rate single-pixel imaging method.

Single-pixel imaging requires only a unit detector with no spatial resolution capability to acquire spatial information of the target and reconstruct the image. However, the quality of reconstructing images strongly depends on measurement matrices and their number of samples, making it challenging to achieve high-quality imaging with fewer samples. In this Letter, a dataset-driven low-sampling-rate single-pixel imaging method is proposed. It utilizes a network model driven by the image datasets to directly extract target feature information from a small number of samples and reconstruct the image. Experimental results demonstrate that, compared to traditional single-pixel imaging methods, this method no longer depends strongly on the relationship between the measurement matrices and the samples, and it can achieve an ideal imaging effect with a structural similarity of 90.20% at low sampling rates.

Pancreatic Cancer and its Attributable Risk Factors in East Asia, Now and Future.

BACKGROUND: The disease burden of pancreatic cancer in East Asia is at a high level, but the epidemiological characteristics of pancreatic cancer in the region have not been systematically studied. METHOD: Joinpoint analysis was used to identify average annual percentage change (AAPC) and annual percentage change (APC) in mortality. Age-period-cohort models were used to analyze age-period cohort effects across countries. Bayesian age-period-cohort (BAPC) analysis was used to project the burden of disease for 2020-2030. RESULTS: Pancreatic cancer mortality in males in Japan (2012-2019, APC = -0.97) and Korea (2012-2019, APC = -0.91) has shown a decreasing trend since 2012 (P < .05). However, China (2016-2019, APC = 3.21), Mongolia (2015-2.019, APC = 2.37), and North Korea (2012-2019, APC = 0.47) showed a significant increase in pancreatic cancer in both genders (P < .05). Risk factors for pancreatic cancer in East Asia remained largely stable between 2010 and 2019. Mortality of pancreatic cancer due to smoking began to decline in areas with high socio-demographic index (SDI), and mortality of pancreatic cancer due to high body mass index and high fasting plasma glucose increased with SDI. The age-standardized mortality for pancreatic cancer in Chinese males is expected to exceed that of Japan and South Korea by 2030, but the disease burden of pancreatic cancer in Japan and South Korea remains at extremely high levels. CONCLUSION: Economically developed countries are beginning to show a decreasing trend in the burden of pancreatic cancer disease, and developing countries are experiencing a rapid increase in the age-standardized death rate (ASDR) of pancreatic cancer.

Development of multiplex cross displacement amplification combined with lateral flow biosensor assay for detection of virulent shigella sonnei.

Shigella sonnei is the most common Shigella spp. in developed areas and the second most common in undeveloped regions. In this study, a multiple cross displacement amplification (MCDA) assay was used in combination with a lateral flow biosensor (LFB) assay to detect virulent S. sonnei strains containing the ipaH and wbgX genes. The multiplex MCDA-LFB assay detected wbgX at ≥1 pg/µL and ipaH at ≥10 fg/µL within 30 min in pure cultures maintained at 63°C. This assay was sensitive for ~37 CFU of virulent S. sonnei and ~3.7 CFU of Shigella spp. and enteroinvasive E. coli in stimulated fecal samples and had 100% specificity among 59 reference strains. The MCDA-LFB assay was also able to differentiate between virulent S. sonnei and other Shigella spp. and enteroinvasive E. coli among 99 clinical isolates. In summary, a multiplex MCDA-LFB assay was developed for rapid, convenient, point-of-care, and accurate identification of virulent S. sonnei within 30 min and at a constant temperature without the need for expensive lab equipment.

A molecular study regarding the spread of vanA vancomycin-resistant Enterococcus faecium in a tertiary hospital in China.

OBJECTIVES: Vancomycin-resistant enterococci (VRE) are one of the most important bacterial causes of healthcare-associated infections (HAIs). In China, the detection rate of VRE Enterococcus faecium (VREfm) is low, although VREfm had a high prevalence in our hospitals between 2013-2015. In this study, we used molecular typing methods combined with epidemiological data to investigate the spread of VREfm in our hospital. METHODS: The characteristics of E. faecium strains isolated from 89 patients with HAIs, including antibiotic susceptibility and virulence genes, were analyzed. This study analyzed 50 E. faecium strains isolated from 47 intensive care unit and Emergency ward patients using core genome Multilocus Sequence Typing and transposon typing. Epidemiological information about those patients was also analyzed. RESULTS: Twenty-seven E. faecium isolates containing the vanA gene were identified as VREfm in 89 non-duplicate E. faecium isolates. The major clonal VREfm strains that persisted from 2013-2015 were CT1/ST78/PFGE cluster A that contained transposon type Ⅰ. The other CT4/ST363/PFGE cluster of VREfm strains also contained transposon type Ⅰ. Three patients acquired different clonal E. faecium strains during the hospital period, and the VREfm strain infected one patient. CONCLUSIONS: In this study, we report the spread caused by vanA vancomycin-resistant E. faecium strains of different cluster types with the same type of transposon in a tertiary hospital. Our literature review revealed that this is the first report of the HAIs caused by ST363/CT4 VREfm strains.

Initial Stage Carbonization of γ-Fe(100) Surface in C2H2 under High Temperature: A Molecular Dynamic Simulation.

In the present work, initial stage carbonization of γ-Fe(100) surface in C2H2 from 1000 K to 1600 K has been investigated by a molecular dynamic (MD) simulation, based on which the atomic mechanism of initial stage carbonization was provided. The absorption of C and H atoms during the carbonization process under different temperatures was analyzed. The related distributions of C and H atoms in carbonized layer were provided. The results manifested that higher temperature enhanced the inward diffusion of C and H, meanwhile caused the desorption of H atom. Furthermore, the effect of preset polycrystal γ-Fe on the carbonization process has been discussed, indicating a promoting role to the absorption and inner diffusion of C and H atom. The results of this study may support the optimal design of high-performance steel to some extent.

Retrieval of molecular alignment and identification of multiple-orbital contribution by using polarized high harmonics from aligned N2 molecules.

With the parallel and perpendicular components of high harmonics generated by using aligned N2 molecules, we propose a method to retrieve the alignment distribution induced by the aligning laser based on the quantitative rescattering theory. And the intensity of pump laser and gas temperature can be precisely determined as well. We find that the intensity ratio between two harmonic components is very sensitive to the inclusion of multiple-orbital contribution in the theory. We thus suggest that it could be used to identify the interference from inner orbitals by tuning input laser power or extending the spectral region of high harmonics.

Role of initial stage nitridation on the mechanical properties of an α-Fe(100) nanofilm in NH3.

Nitrogen is one of the most significant non-native interstitial elements that is present in the structure of Fe. Initial stage nitridation dramatically influences the mechanical properties of steel, especially for micro to nanoscale applications, but is not yet fully understood. By means of reactive force field molecular dynamics (ReaxFF MD) simulations, the initial stage of the nitridation process of nanofilm Fe, as well as its role on the mechanical properties of the material, were investigated. To clarify the temperature effect, nitridation was simulated in the range of 500-900 K, demonstrating that the adsorption of both N and H atoms into Fe was enhanced by thermal actuation. Corresponding tension test simulations were performed, manifesting that the Fe nanofilm nitrided at 600 K presents the highest yield stress. Further analysis shows that there is a competitive mechanism between the inward diffusion of N atoms that enhances the strength and simultaneous adsorption of H atoms, which leads to brittleness of the material as the temperature increases. Hence, an intermediate temperature could lead to optimal mechanical properties due to the balance of improving the strength while controlling the brittleness of the material. To probe the deformation mechanism, evolutions of partial dislocation and twin boundary at plasticity beginning for pure Fe and the nitrided Fe nanofilm are discussed. The present results show the nitridation strengthening technology of Fe in NH3 and its related microscale mechanism, which may theoretically support the technical design and improvement in the properties of steel.

Could the arm blood pressure measured with simultaneous bilateral arm method be used for hypertension diagnosis?

OBJECTIVE: Simultaneous bilateral arm blood pressure (BP) measurement (bilateral arm method) is suggested for the first BP measurement in clinical practice, but whether the arm BP measured with bilateral arm method (RA-2) is similar to that with unilateral arm method (RA-1) is unclear. DESIGN: Quantitative research, paired sample T-test, Bland-Altman and multivariate linear regression analyses were used. SETTING: This study included 295 subjects (18-90 years, 60.0±14.6 years old, 126 males) in the clinic of cardiovascular medicine of the Second Affiliated Hospital of Nanchang University. They were randomly instructed to one of two BP measurement proposals: (1) right-arm-bilateral arm-right-arm-bilateral arm, or (2) bilateral arm-right-arm-bilateral arm-right-arm to attenuate bias induced by BP measurement order. PARTICIPANTS: From June to October of 2019, 295 outpatients (18-90 years, 60.0±14.6 years old, 126 males and 169 females) with sinus rhythm (SR) were enrolled. The exclusion criteria were acute myocardial infarction, congenital heart disease, acute heart failure, syncope, hemiplegia, arrhythmia and pulseless (by palpation). OUTCOME MEASURES: We compared the BP differences between bilateral arm method and unilateral arm method. The difference between RA-2 and RA-1 was calculated as Dif-RA. Data are expressed as means±SD for continuous variables. The percentage increase (PI) was calculated on the formula: (RA-2-RA-1)/RA-1. RESULTS: The RA-2 on systolic blood pressure (SBP)/diastolic blood pressure (DBP) was slightly, but statistically higher by 1.2/0.4 mm Hg against the RA-1. Multivariate regression analyses showed that hypertension therapy type was positive impact factor, but RA-1 was negative factor for PI of Dif-RA on SBP, DBP and pulse pressure. CONCLUSION: The SBP and DBP of right arm measured with bilateral arm method are slightly, but statistically higher (1.2 and 0.4 mm Hg) than those with the unilateral arm BP method.

[Characteristics of distribution and changes of telomere length in human].

OBJECTIVE: To explore the relationship between telomere length changes and age, and to provide data and reference for further study of geriatric medical problems.
 Methods: The healthy people over 20 years old were chosen as subject from several hospitals by random sampling method, and their peripheral blood samples were collected. The relative length of telomere was detected by quantitative real-time PCR, and the relationship between age and telomere length was analyzed by statistical software.
 Results: A total of 1 022 samples were obtained. There were significant differences in the relative telomere length among different age groups (F=21.492, P<0.001). Telomere length and age showed negative correlation (r=-0.325, P<0.001), the regression equation was y=-0.008x+1.772 (x for age, y for the average telomere length, P<0.001).
 Conclusion: The telomere length for peripheral blood leukocytes in healthy people varies between different age groups, suggesting that telomere length gradually decreases with age.

[Evaluation of the aging status and distribution characteristics for male population by three-dimensional human aging scale].

OBJECTIVE: To investigate the ageing status for male population aged or over 20 years old in urban communities, clarifying their distribution characteristics and rules, and to provide reference for aging research.
 Methods: A total of 1 120 men aged or over 20 years old in Nanchang were obtained by stratified sampling, and the aging scale was measured in 9 groups. The distribution characteristics of aging scores were analyzed by normality test, variance analysis, and linear correlation.
 Results: The total score of aging and the scores of physiological, psychological, and physiological dimensions were 54.01±9.24, 32.33±7.54, 14.66±1.64, and 7.02±1.16, respectively. The scores were positively correlated with age. The total score curve of aging was significantly increased in the 25-<30 and 30-<40, 65-<70 and 70-<75 years old groups. The physiological dimension curve was similar to the total score curve. The psychological dimension curve was more pronounced at 55-<60 and 60-<65 years old groups. The social dimension curve raised slowly and smoothly at all ages.
 Conclusion: The total score and the scores for all dimensions of male physiological-psycho-sociological increase with age; and changes near the age group of 55-<60 and 60-<65 are obvious, providing reference for the understanding of male aging.

[Application of the psychological aging scale for healthy people: A preliminary study based on empirical research].

OBJECTIVE: To explore the distribution of psychological aging in healthy population and its relationship with telomere length in peripheral blood leukocyte, and to provide reference for aging evaluation.
 Methods: Stratified random samples were obtained according to age and they were divided into 9 age groups. The age-related psychological information were collected from healthy people by using the self-made scale. Situation of psychological aging, correlation between age and telomere length and score of this scale were analyzed by statistical software.
 Results: A total of 2 100 questionnaires were distributed, and 2 060 of them were valid and has been recovered, with an efficiency of 98.10%. The ratio of male to female was 0.95:1; psychological aging score was in the range of 8.62-23.14; cognitive function score was in the range of 2.25-10.77; emotion score was in the range of 1.45-6.73; personality score was in the range of 0.96-4.22; motivation score was in the range of 1.50-7.18. The correlation coefficient of psychological aging scores with age was 0.721 (P<0.001). The average relative telomere length was 1.06±0.26, and relative telomere length in different age groups were significantly different (F=35.803, P<0.001). Telomere length was negatively correlated with age (r=-0.964, P<0.001) and psychological aging scores (r=-0.915, P=0.004).
 Conclusion: The empirical study of physiological aging scale in healthy population shows that the scores of physical aging are increased with age and that the telomere length is negatively correlated with aging scores, suggesting that the scale can provide reference for the comprehensive evaluation of aging.