Enrichment of Terbium(III) under synergistic effect of biosorption and biomineralization by Bacillus sp. DW015 and Sporosarcina pasteurii.

Biosorption and biomineralization are commonly used for the immobilization of metal ions. Biosorption is commonly used as a green method to enrich rare earth ions from wastewater. However, little attention has been paid to the facilitating role of biomineralization in the enrichment of rare earth ions. In this study, a strain of Bacillus sp. DW015, isolated from ion adsorption type rare earth ores and a urease-producing strain Sporosarcina pasteurii were used to enrich rare earth elements (REEs) from an aqueous solution. The results indicate that biomineralization accelerates the enrichment of Terbium(III) compared to biosorption alone. Kinetic analysis suggests that the main mode of action of DW015 was biosorption, following pseudo-second-order kinetics (R2 = 0.998). The biomineralization of DW015 did not significantly contribute to the enrichment of Tb(III), whereas excessive biomineralization of S. pasteurii led to a decrease in the enrichment of Tb(III). A synergistic system of biosorption and biomineralization was established by combining the two bacteria, with the optimal mixed bacteria (S. pasteurii:DW015) ratio being 1:19. This study provides fundamental support for the synergistic effect of biosorption and biomineralization and offers a new reference for future microbial-based enrichment methods. IMPORTANCE: A weak microbially induced calcium carbonate precipitation (MICP) promotes the enrichment of Tb(III) by bacteria, while a strong MICP leads to the release of Tb(III). However, existing explanations cannot elucidate these mechanisms. In this study, the morphology of the bioprecipitation and the degree of Tb(III) enrichment were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The data revealed that MICP could drive stable attachment of Tb(III) onto the cell surface, forming a Tb-CaCO3 mixed solid phase. Excessive rapid rate of calcite generation could disrupt the Tb(III) adsorption equilibrium, leading to the release of Tb(III). Therefore, in order for Tb(III) to be stably embedded in calcite, it is necessary to have a sufficient number of adsorption sites on the bacteria and to regulate the rate of MICP. This study provides theoretical support for the process design of MICP for the enrichment of rare earth ions.

Insight into effects of terbium on cell growth, sporulation and spore properties of Bacillus subtilis.

Recovery of rare earth elements (REEs) from wastewater with Bacillus subtilis (B. subtilis) during culture is promising due to its environmental benefits. However, the effects of REEs in the culture media on B. subtilis are poorly understood. This study aims to investigate the effects of the terbium (Tb(III)), a typical rare earth element, on the cell growth, sporulation, and spore properties of B. subtilis. Tb(III) can suppress bacterial growth while enhancing spore tolerance to wet heat. Spore germination and content of dipicolinic acid (DPA) were promoted at low concentrations of Tb(III) while inhibited at a high level, but an inverse effect on initial sporulation appeared. Scanning electron microscope and energy dispersive spectrometer detection indicated that Tb(III) complexed cells or spores and certain media components simultaneously. The germination results of the spores after elution revealed that Tb(III) attached to the spore surface was a key effector of spore germination. In conclusion, Tb(III) directly or indirectly regulated both the nutrient status of the media and certain metabolic events, which in turn affected most of the properties of B. subtilis. Compared to the coat-deficient strain, the wild-type strain grew faster and was more tolerant to Tb(III), DPA, and wet heat, which in turn implied that it was more suitable for the recovery of REEs during cultivation. These findings provide fundamental insights for the recovery of rare earths during the culture process using microorganisms.

Liver volume based prediction model for patients with hepatitis B virus-related acute-on-chronic liver failure.

BACKGROUND: Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a life-threatening disease with high short-term mortality. Early and accurate prognosis is significant for clinical decisions, in which liver volume (LV) imparts important information. However, LV has not been considered in current prognostic models for HBV-ACLF. METHODS: Three hundred and twenty-three patients were recruited to the deriving cohort, while 163 were enrolled to validation cohort. The primary end-point was death within 28 days since admission. Estimated liver volume (ELV) was calculated by the formula based on healthy population. Logistic regression was used to develop a prediction model. Accuracy of models were evaluated by receiver operating characteristic (ROC) curves. RESULTS: The ratio of LV to ELV (LV/ELV%) was significantly lower in non-survivors, and LV/ELV% ≤82% indicated poor prognosis. LV/ELV%, Age, prothrombin time (PT), the grade of hepatic encephalopathy (HE), ln-transformed total bilirubin (lnTBil), and log-transformed HBV DNA (Log10 HBV DNA) were identified as independent predictors to develop an LV-based model, LEAP-HBV. The mean area under the ROC (AUC) of LEAP-HBV was 0.906 (95% CI, 0.904-0.908), higher than other non-LV-based models. CONCLUSION: Liver volume was an independent predictor, and LEAP-HBV, a prediction model based on LV, was developed for the short-term mortality in HBV-ACLF. This study was registered on ClinicalTrails (NCT03977857).

Clinical Characteristics and Outcomes of Acute Ischemic Stroke in Patients with Type 2 Diabetes: A Single-Center, Retrospective Study in Southern China.

OBJECTIVE: To explore the associations between type 2 diabetes mellitus (DM) and stroke by evaluating the clinical risk factors, characteristics, and outcomes of acute ischemic stroke (AIS) patients with and without type 2 DM. METHODS: A total of 1,156 AIS patients (including 410 with type 2 DM (AIS-DM group)) and 746 without type 2 DM (AIS-NDM group)) were included. Patients' demographics, auxiliary examinations, clinical manifestations, and treatment outcomes were recorded and analyzed. RESULTS: Among the included AIS patients, 35.46% had type 2 DM. The AIS-DM group had less males (59.76% versus 70.64%), less smokers (33.90% versus 41.96%), more patients with hypertension (72.93% versus 63.94%; p=0.002), higher triglyceride levels (42.93% versus 25.08%; p ≤ 0.01), and lower total cholesterol (147.06 mg/dl versus 175.31 mg/dl) than the AIS-NDM group. The proportion of patients with large artery atherosclerosis (LAA) in the AIS-DM group was lower (77.56% versus 85.92%; p < 0.05) than that in the AIS-NDM group, and the proportion of patients with small arterial occlusions (SAO) in the AIS-DM group was higher (27.07% versus 13.67%; p < 0.05) than that in the AIS-NDM group. The mean National Institutes of Health Stroke Scale (NIHSS) score at admission in the AIS-DM group was lower than that in the AIS-NDM group (4.39 versus 5.00; p=0.008), but there was no significant difference in the NIHSS score or the modified Rankin Scale score between the two groups at discharge. A total of 85 AIS patients underwent intravenous thrombolysis treatment with recombinant tissue plasminogen activator (rtPA). The door-to-needle time (DNT) did not differ significantly between the groups (49.39 ± 30.40 min versus 44.25 ± 15.24 min; p=0.433). In addition, there were no significant differences in the baseline NIHSS score, 7-day NIHSS score, and mRS score at discharge between the groups. After intravenous thrombolysis with rtPA, the AIS-NDM group had better recovery (44.30% versus 29.20%; p=0.017) and a higher ratio of good treatment outcome at discharge (65.60% versus 54.20%; p=0.762). CONCLUSIONS: Type 2 DM is associated with AIS and its risk factors, such as dyslipidemia and hypertension. Patients in the AIS-DM group had less LAA and smaller arterial occlusions, and DM could exacerbate the short-term clinical outcomes in AIS patients.

CANPT Score: A Tool to Predict Severe COVID-19 on Admission.

Background and Aims: Patients with critical coronavirus disease 2019 (COVID-19) have a mortality rate higher than 50%. The purpose of this study was to establish a model for the prediction of the risk of severe disease and/or death in patients with COVID-19 on admission. Materials and Methods: Patients diagnosed with COVID-19 in four hospitals in China from January 22, 2020 to April 15, 2020 were retrospectively enrolled. The demographic, laboratory, and clinical data of the patients with COVID-19 were collected. The independent risk factors related to the severity of and death due to COVID-19 were identified with a multivariate logistic regression; a nomogram and prediction model were established. The area under the receiver operating characteristic curve (AUROC) and predictive accuracy were used to evaluate the model's effectiveness. Results: In total, 582 patients with COVID-19, including 116 patients with severe disease, were enrolled. Their comorbidities, body temperature, neutrophil-to-lymphocyte ratio (NLR), platelet (PLT) count, and levels of total bilirubin (Tbil), creatinine (Cr), creatine kinase (CK), and albumin (Alb) were independent risk factors for severe disease. A nomogram was generated based on these eight variables with a predictive accuracy of 85.9% and an AUROC of 0.858 (95% CI, 0.823-0.893). Based on the nomogram, the CANPT score was established with cut-off values of 12 and 16. The percentages of patients with severe disease in the groups with CANPT scores <12, ≥12, and <16, and ≥16 were 4.15, 27.43, and 69.64%, respectively. Seventeen patients died. NLR, Cr, CK, and Alb were independent risk factors for mortality, and the CAN score was established to predict mortality. With a cut-off value of 15, the predictive accuracy was 97.4%, and the AUROC was 0.903 (95% CI 0.832, 0.974). Conclusions: The CANPT and CAN scores can predict the risk of severe disease and mortality in COVID-19 patients on admission.

Machine learning-based CT radiomics method for predicting hospital stay in patients with pneumonia associated with SARS-CoV-2 infection: a multicenter study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) has become a global challenge since the December 2019. The hospital stay is one of the prognostic indicators, and its predicting model based on CT radiomics features is important for assessing the patients' clinical outcome. The study aimed to develop and test machine learning-based CT radiomics models for predicting hospital stay in patients with COVID-19 pneumonia. METHODS: This retrospective, multicenter study enrolled patients with laboratory-confirmed SARS-CoV-2 infection and their initial CT images from 5 designated hospitals in Ankang, Lishui, Lanzhou, Linxia, and Zhenjiang between January 23, 2020 and February 8, 2020. Patients were classified into short-term (≤10 days) and long-term hospital stay (>10 days). CT radiomics models based on logistic regression (LR) and random forest (RF) were developed on features from pneumonia lesions in first four centers. The predictive performance was evaluated in fifth center (test dataset) on lung lobe- and patients-level. RESULTS: A total of 52 patients were enrolled from designated hospitals. As of February 20, 21 patients remained in hospital or with non-findings in CT were excluded. Therefore, 31 patients with 72 lesion segments were included in analysis. The CT radiomics models based on 6 second-order features were effective in discriminating short- and long-term hospital stay in patients with COVID-19 pneumonia, with areas under the curves of 0.97 (95% CI, 0.83-1.0) and 0.92 (95% CI, 0.67-1.0) by LR and RF, respectively, in test. The LR and RF model showed a sensitivity and specificity of 1.0 and 0.89, 0.75 and 1.0 in test respectively. As of February 28, a prospective cohort of six discharged patients were all correctly recognized as long-term stay using RF and LR models. CONCLUSIONS: The machine learning-based CT radiomics features and models showed feasibility and accuracy for predicting hospital stay in patients with COVID-19 pneumonia.

A colorimetric assay for sensitive detection of hydrogen peroxide and glucose in microfluidic paper-based analytical devices integrated with starch-iodide-gelatin system.

Microfluidic paper-based analytical devices (µPADs) for detection of hydrogen peroxide and glucose have been developed. The analytical performance of colorimetric detection using the conventional starch-iodine color reaction has been significantly improved by using gelatin as the surface modifier which retains the enzyme activity in the dry filter paper strip, improves antioxidability, as well as decreases the strong background signal. Under optimal conditions, the color intensities show a good linear relationship with glucose concentration ranging from 0.5 to 5 mM and hydrogen peroxide concentration from 0.5 to 6 mM, with the detection limit of 0.05 mM and 0.1 mM, respectively. In addition, the accuracy of colorimetric sensor has been successfully assessed in detecting glucose from real human serum samples and recovery value ranges from 95.7% to 97%, which are approaching to the glucose oxidase endpoint. The new colorimetric assay exhibits high sensitivity, good selectivity, acceptable stability and reproducibility. The present approach is promising for monitoring glucose for point of care diagnostic applications, especially in regions with resource-limited settings.

Simple synthesized Pt/GNs/TiO2 with good mass activity and stability for methanol oxidation.

Pt/GNs/TiO2 (GNs, graphene nanosheets) catalyst was synthesized by a simple two-step method, including a rapid solution plasma technique to obtained Pt nanoparticles with a size of 2-5 nm and followed by an ultrasonic mixing of the Pt, GNs and TiO2 nanoparticles. After coupling with TiO2 nanoparticles, the Pt/GNs/TiO2 catalyst exhibited a promoting catalytic activity towards methanol oxidation, which was superior to the Pt/GNs catalyst. The mass activity of the Pt/GNs/TiO2 catalyst was 3464 mA mgPt-1, which was 3.5 and 3.4 times higher than those of the Pt/GNs and the commercial Pt/C, respectively. And the Pt/GNs/TiO2 showed a strongly negative shift onset potential of methanol oxidation. The results of long-term cyclic voltammetry and CO-stripping tests showed an improved CO tolerance of the Pt/GNs/TiO2. Moreover, the mass activity of the Pt/GNs/TiO2 was further enhanced under light irradiation, with the mass activity of 4715 mA mgPt-1, which was 1.4 times higher than that of in dark. This work provides new opportunities for exploiting efficient visible photo-assisted electro-catalytic methanol oxidation.

Facile Fabrication of Platinum-Cobalt Alloy Nanoparticles with Enhanced Electrocatalytic Activity for a Methanol Oxidation Reaction.

Decreasing the cost associated with platinum-based catalysts along with improving their catalytic properties is a major challenge for commercial direct methanol fuel cells. In this work, a simple and facile strategy was developed for the more efficient preparation of multi-walled carbon nanotube (MWCNT) -supported Pt/CoPt composite nanoparticles (NPs) via solution plasma sputtering with subsequent thermal annealing. Quite different from general wet synthesis methods, Pt/CoPt composite NPs were directly derived from metal wire electrodes without any additions. The obtained Pt/CoPt/MWCNTs composite catalysts exhibited tremendous improvement in the electro-oxidation of methanol in acidic media with mass activities of 1719 mA mg-1Pt. This value is much higher than that of previous reports of Pt-Co alloy and commercial Pt/C (3.16 times) because of the many active sites and clean surface of the catalysts. The catalysts showed good stability due to the special synergistic effects of the CoPt alloy. Pt/CoPt/MWCNTs can be used as a promising catalyst for direct methanol fuel cells. In addition, this solution plasma sputtering-assisted synthesis method introduces a general and feasible route for the synthesis of binary alloys.

Synthesis and photocatalytic activity of Pt-ZnO hybrid nanocomposite by solution plasma technology.

In this paper, Pt-ZnO hybrid nanocomposites were prepared by solution plasma technology. X-ray diffraction (XRD) and energy dispersive x-ray analysis (EDX) were used to verify their chemical composition. The size and morphology of the Pt-ZnO hybrid nanocomposites were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These results indicate that about 2-3 nm Pt nanoparticles (NPs) were synthesized and dispersed on the pyramid-like ZnO (20-60 nm) surface. Photodegradation of Rhodamine B (RhB) demonstrates that the Pt (5 wt%)-ZnO hybrid nanocomposite has better photocatalytic activity than commercial P25 because Pt NPs restrain the photogenerated electron/hole recombination and increase the catalyst activity.

Therapeutic effects of lipo-prostaglandin E1 on angiogenesis and neurogenesis after ischemic stroke in rats.

Previous studies have demonstrated that prostaglandin E1 (PGE1) has a neuroprotective effect on cerebral ischemia. However, it remains unknown whether PGE1 promotes angiogenesis and neurogenesis after ischemic stroke. In this study, adult male Sprague-Dawley rats were subjected to permanently distal middle cerebral artery occlusion (MCAO). Rats were treated with lipo-prostaglandin E1(lipo-PGE1, 10 µg/kg/d) or the same volume of 0.9% saline starting 24 hours after MCAO daily for 6 consecutive days. All rats were injected 5'-bromo-2'-deoxyuridine (BrdU, 50 mg/kg) intraperitoneally every 12 hours for 3 consecutive days before being sacrificed. At 7 and 14 days after MCAO or sham-operation, rats were sacrificed. Post-stroke neurological outcome, infarction volume, angiogenesis and neurogenesis were evaluated. Treatment with lipo-PGE1 significantly increased the vascular density in the peri-infarct areas at 7 and 14 days after MCAO. The lipo-PGE1 treatment significantly enhanced the proliferation and migration of endogenous neural stem cells in the ipsilateral subventricular zone. The neural stem cells associated with blood vessels closely within a neurovascular niche in lipo-PGE1-treated rats after stroke. The lipo-PGE1 treatment also significantly improved the neurological recovery after MCAO. These results indicate that treatment with lipo-PGE1 promotes post-stroke angiogenesis, neurogenesis and their interaction, which would contribute to neurological recovery after cerebral infarction. Our study provides novel experimental evidences for the neuroprotective roles of PGE1 in ischemic stroke.

[A novel method for hepatitis C virus genotyping using RT-PCR reverse dot blot hybridization technique].

OBJECTIVE: To develop a rapid and specific method for hepatitis C virus ( HCV) genotyping using reverse dot blot hybridization technique and investigate the distribution of HCV genotypes and subtypes in Guangdong. METHODS: The primers and the probes targeting the 5'untranslated region (5'UTR) and core region of HCV genotypes 1b, 2a, 3a, 3b and 6a were designed, and the RT-PCR reverse dot blot hybridization (PCR-RDH) method for HCV genotyping was established. A total of 115 patients with hepatitis C were genotyped using this method, and 38 of them were also genotyped by sequencing and phylogenetic analysis to evaluate the accuracy and specificity of the method. RESULTS: Of the 115 patients, 111 were successfully genotyped to be 1b, 2a, 3a, 3b, 6a and mix-infection of 1b/2a at frequencies of 56.8%, 8.1 %, 3.6%, 5.4%, 25.2% and 0.9% respectively, and all the 15 healthy control samples showed negative results. The accuracy and reliability of the genotyping method of PCR-RDH was confirmed in 38 cases by amplification of HCV core and NS5B regions followed by DNA sequencing and phylogenetic analysis. CONCLUSION: This method for HCV genotyping, with high reliability and specificity, is suitable for clinical and epidemiological investigations. The prevalence of HCV genotypes 1b and 2a decreases while 1b remains the dominant genotype in Guangdong, where the prevalence of 6a significantly increases as compared with that 10 years ago.