A novel 2-dimensional graphene analog molybdenum disulfide/multi-walled carbon nanotube (MoS2/MWCNT) was synthesized by a simple hydrothermal method to achieve excellent electrochemical properties. ...An ultrasensitive electrochemical DNA biosensor was subsequently constructed by assembling a thiol-tagged DNA probe on a MoS2/MWCNT and gold nanoparticle (AuNP)-modified electrode that has already been coupled with glucose oxidase (GOD). In this work, GOD was used as a redox marker. The heteronanostructure formed on the biosensor surface appeared relatively good conductor for accelerating the electron transfer, while the modification of GOD and AuNPs provided multiple signal amplification for electrochemical biosensing. The multiple signal amplification strategy produced an ultrasensitive electrochemical detection of DNA down to 0.79fM with a linear range from 10fM to 107fM, and appeared high selectivity to differentiate three-base mismatched DNA and one-base mismatched DNA. The developed approach provided a simple and reliable method for DNA detection with high sensitivity and specificity, and would open new opportunities for sensitive detection of other biorecognition events.
•A novel amplification strategy for electrochemical DNA sensor was reported.•MoS2/MWCNTs, Au nanoparticle and enzyme were employed to amplify the signals.•The biosensor can discriminate target DNA from 1-base mismatch DNA.•The developed biosensor can detect DNA down to sub-femtomolar level.
A 3D porous perchlorinated metal–organic framework (MOF), LIFM‐26, featuring dual functionality, that is, functional polar groups and open metal sites, has been synthesized using perchlorinated ...linear dicarboxylate to link trigonal prismatic Fe3(μ3‐O) units. LIFM‐26 exhibits good thermal and chemical stability, and possesses high porosity with a BET surface area of 1513 m2 g−1, compared with isoreticular MOF‐235 and Fe3O(F4BDC)3(H2O)3 (F4BDC=2,3,5,6‐tetrafluorobenzene‐1,4‐dicarboxylate). Most strikingly, LIFM‐26 features good gas sorption/separation performance at 298 K and 1 atm with IAST selectivity values reaching up to 36, 93, 23, 11, 46, and 202 for CO2/CH4, CO2/N2, C2H4/CH4, C2H6/CH4, C3H8/CH4, and R22/N2 (R22=CHClF2), respectively, showing potential for use in biogas/natural gas purification and CO2/R22 capture.
A versatile MOF: A 3D porous perchlorinated metal–organic framework (MOF), LIFM‐26, featuring dual functionality, polar functional groups, and open metal sites, has been synthesized and characterized. It shows good thermal and chemical stability. In addition, it exhibits excellent adsorption selectivities for CO2 versus N2 and CH4, C2+ hydrocarbons versus CH4, and CHClF2 (R22) versus N2.
Background
The factors associated with anti‐N‐methyl‐D‐aspartate (NMDA) receptor encephalitis relapse are yet to be elucidated.
Aims of the Study
To investigate the factors associated with relapse ...and prognosis of anti‐NMDA receptor encephalitis.
Methods
This retrospective study included patients diagnosed with anti‐NMDA receptor encephalitis admitted to the First Affiliated Hospital of Zhengzhou University from January 2013 to October 2019. The clinical features, auxiliary examinations, treatment regimens, and follow‐up were recorded. The outcomes were relapse and 2‐year disease prognosis.
Results
A total of 160 patients were included. Consequently, 6 (5%) deaths, 34 (25.4%) relapses, and 19 (15.2%) patients had a poor prognosis (modified Rankin score (mRS) ≥3) were recorded. The multivariable analyses showed that age (p = .011), abnormal magnetic resonance imaging (MRI) (p = .019), glucocorticoid pulse (p = .009), and intracranial pressure (p = .023) were independently associated with the relapse, while age (p = .030) and central hypoventilation (p = .020) were independently associated with a poor prognosis at 2 years.
Conclusion
Glucocorticoid pulse therapy reduces the relapse of anti‐NMDA receptor encephalitis. Age, abnormal MRI, and intracranial pressure are risk factors for relapse, while age and central hypoventilation are independently associated with poor prognosis.
This study aimed to investigate the clinical features, distribution, and antimicrobial susceptibility of Nocardia species isolated from pulmonary nocardiosis cases in a tertiary hospital in China. ...The species were collected from January 1, 2018, to May 31, 2019, and identified using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry or polymerase chain reaction. Antimicrobial susceptibility testing was performed using the broth microdilution method. Within the 44 Nocardia species, N. farcinica was the most frequently identified species (n = 36), followed by N. nova (n = 5), N. otitidiscaviarum (n = 1), N. cyriacigeorgica (n = 1), and N. transvalensis (n = 1). The top 3 predisposing factors of pulmonary nocardiosis were chronic obstructive pulmonary disease (45.5%), hypertension (34.1%), and tuberculosis (31.8%). All 44 Nocardia species were susceptible to amikacin, trimethoprim/sulfamethoxazole, and linezolid. The resistance rates of Nocardia to amoxicillin-clavulanic acid, ciprofloxacin, clarithromycin, ceftriaxone, tobramycin, and imipenem were 4.5%, 9.1%, 79.5%, 72.7%, 63.6%, and 38.6%, respectively. Two Nocardia strains had decreased sensitivity to trimethoprim/sulfamethoxazole. In conclusion, N. farcinica was the most frequently isolated Nocardia species in the First Hospital of Changsha. All the isolated clinical Nocardia species showed susceptibility to amikacin, trimethoprim/sulfamethoxazole, and linezolid, suggesting that these drugs can be primary therapeutic choices for treating Nocardia infections.
Schaftoside and isoschaftoside are bioactive natural products widely distributed in higher plants including cereal crops and medicinal herbs. Their biosynthesis may be related with plant defense. ...However, little is known on the glycosylation biosynthetic pathway of these flavonoid di-C-glycosides with different sugar residues. Herein, we report that the biosynthesis of (iso)schaftosides is sequentially catalyzed by two C-glycosyltransferases (CGTs), i.e., CGTa for C-glucosylation of the 2-hydroxyflavanone aglycone and CGTb for C-arabinosylation of the mono-C-glucoside. The two enzymes of the same plant exhibit high homology but remarkably different sugar acceptor and donor selectivities. A total of 14 CGTa and CGTb enzymes were cloned and characterized from seven dicot and monocot plants, including Scutellaria baicalensis, Glycyrrhiza uralensis, Oryza sativa ssp. japonica, and Zea mays, and the in vivo functions for three enzymes were verified by RNA interference and overexpression. Through transcriptome analysis,we found homologous genes in 119 other plants, indicating this pathway is general for the biosynthesis of (iso)schaftosides. Furthermore, we resolved the crystal structures of five CGTs and realized the functional switch of SbCGTb to SbCGTa by structural analysis and mutagenesis of key amino acids. The CGT enzymes discovered in this paper allow efficient synthesis of (iso)schaftosides, and the general glycosylation pathway presents a platform to study the chemical defense mechanisms of higher plants.
•Food directly promotes the tolerance of gastropods to ammonia.•Sediment and macrophyte decrease ammonia toxicity by ammonia absorption.•Sediment and macrophyte provide extra food for ...gastropods.•Sediment shelters gastropods from direct exposure to high ammonia concentrations.
The toxic effect of unionized ammonia (NH3) on aquatic organisms is receiving increasing attention due to the excessive nitrogen discharge to various surface waters. Researches have suggested the scale-dependence of NH3 toxicity, being lower in field than under lab conditions. Such scale-dependence of toxicity is a big challenge to water quality criteria setting as the results solely from lab tests might not apply to natural ecosystems. Therefore, it is necessary to explore the underlying mechanism to understand the difference of toxicity across various spatial scales. In this study, we used the widely distributed gastropod Bellamya aeruginosa as the test animal and performed two 192-h microcosm experiments. Each experiment included a control and an ammonia addition treatment: N0(LC50) & N+(LC50), N0(LC100) & N+(LC100) (96-h LC50 = 0.8 mg NH3N/L, 96-h LC100 = 18.1 mg NH3N/L). Besides water-only, three potential key components (food, sediment, and submersed macrophytes) were included in the various treatments to mimic different complexity levels of aquatic ecosystems (Water, Water + Food, Water + Sediment, Water + Sediment + Macrophytes). The results showed that: 1) food directly improved the survival and growth of gastropods under expected lethal concentration of ammonia (96-h concentration of NH3N = LC20 of the 96-h acute test); 2) sediment and macrophyte quickly decreased the ammonia concentration, mainly by sediment adsorption and macrophyte uptake, to alleviate the ammonia stress to gastropods and permitted them to survive and grow under expected lethal concentration of ammonia (96-h concentration of NH3N = LC10∼LC20 of the 96-h acute test); 3) sediment and macrophyte also provided additional food for gastropods; 4) under extremely high ammonia stress (i.e., 96-h LC100, food was left uneaten and macrophyte died, and gastropods could, therefore, not be released from ammonia stress. Our results demonstrate that under moderate ammonia stress, the introduction of extra ecosystem elements (food, sediment, and macrophytes) significantly improved the survival and growth of gastropods, mainly by enhancing their tolerance and by quickly decreasing the NH3 concentration and thus toxicity. However, these introduced elements had little effect at very high concentration of ammonia (i.e., 96-h LC100). Our findings add to the understanding of the reasons behind the previous observed scale-dependent toxicity of NH3 on aquatic organisms and contribute to better decisions on the role of NH3 in relation to water quality management.
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