A novel synthetic nucleic acid mixture for quantification of microbes by mNGS.

Metagenomic next-generation sequencing (mNGS) provides considerable advantages in identifying emerging and re-emerging, difficult-to-detect and co-infected pathogens; however, the clinical application of mNGS remains limited primarily due to the lack of quantitative capabilities. This study introduces a novel approach, KingCreate-Quantification (KCQ) system, for quantitative analysis of microbes in clinical specimens by mNGS, which co-sequence the target DNA extracted from the specimens along with a set of synthetic dsDNA molecules used as Internal-Standard (IS). The assay facilitates the conversion of microbial reads into their copy numbers based on IS reads utilizing a mathematical model proposed in this study. The performance of KCQ was systemically evaluated using commercial mock microbes with varying IS input amounts, different proportions of human genomic DNA, and at varying amounts of sequence analysis data. Subsequently, KCQ was applied in microbial quantitation in 36 clinical specimens including blood, bronchoalveolar lavage fluid, cerebrospinal fluid and oropharyngeal swabs. A total of 477 microbe genetic fragments were screened using the bioinformatic system. Of these 83 fragments were quantitatively compared with digital droplet PCR (ddPCR), revealing a correlation coefficient of 0.97 between the quantitative results of KCQ and ddPCR. Our study demonstrated that KCQ presents a practical approach for the quantitative analysis of microbes by mNGS in clinical samples.

In situ assembly of silver nanoparticles throughout electrospun oriented alginate nanofibers for hazardous rust trace detection on bronze.

A convenient and reliable surface-enhanced Raman scattering (SERS) substrate has been developed for the surface corrosion analysis of bronze artifacts. The substrate consists of oriented alginate nanofiber membranes containing silver nanoparticles (Ag NPs), which were obtained through electrostatic spinning, ion exchange, and in-situ reduction. By controlling the reduction time, Ag/alginate nanofiber membranes with different contents, sizes, and distributions were obtained. The Ag/alginate nanofiber#20 membranes, obtained with a reduction time of 20 min, reached a detection limit of 10-12 M for R6G with an enhancement factor of 6.64 × 107. In the trace detection of bronze patina, the intensity of the characteristic peaks of harmful patina located at 513, 846, 911, and 974 cm-1 were increased by more than 500 %. This was due to the uniform loading of a large number of Ag NPs on the surface of the nanofiber membrane obtained by reduction for 20 min, and the formation of a large number of hot spots between the oriented nanofibers. This significantly improved the SERS performance of the flexible substrate layer under the joint action with the Ag NPs. These results indicate that the flexible substrate layer can greatly enhance the Raman characteristic peaks of alkali copper chloride and be effectively used for trace analysis of the surface composition of bronze artifacts.

Design and performance of pH-responsive cyano-Raman label SERS probes based on single urchin Au nanoparticles.

A cyano-Raman label pH-responsive SERS probe was constructed by immobilizing 6-MPN molecules onto the surface of a single urchin Au nanoparticle (AuNP). The effects of different conditions on the synthetic materials were investigated and the optical properties of the single nanoparticles were evaluated. The peak-strength ratio of SERS probes at 1589 cm-1 and 2240 cm-1 exhibited a linear relationship in the pH range 4-7. The properties and stability of the probe were also verified by the acid-base cycle and ion interference tests.

Plasmonic nanoprobes on single AuNTs for evaluating and monitoring the dynamic release of 2D drug carriers.

The use of nanomaterials in drug delivery has gained significant attention in recent years. In this project, we developed a novel localized surface plasmon resonance (LSPR) nanoprobe on single gold triangular nanoplates (AuNTs) for dynamic monitoring of the drug carrier release process. Graphene, as the drug carrier, could be immobilized on the AuNT surface through the π-π* stacking effect. Upon loading or releasing the model drug (doxorubicin, DOX), subtle changes in the local microenvironment's dielectric constant around the AuNTs induced notable red-shifts or blue-shifts in the LSPR scattering spectra of single AuNTs. Furthermore, the spectral shifts led to a continuous enhancement in the red channel of the dark field microscopy (DFM) images during the drug release process in vitro, demonstrating that the drug release system is not susceptible to potential confounding factors. These release kinetics results under different conditions could be well-fitted using the Higuchi desorption model, further proving that this nanoprobe could be employed for evaluating the controlled release ability of 2D nanocarriers. These findings are expected to inspire new ideas and technologies in the preparation of more effective drug carriers, making a significant contribution to the development of drug delivery nanosystems and nanomedicine.

Polysaccharide-Based Supramolecular Hydrogel Coatings with Corrosion Barrier Zone for Protection of Patina Bronze.

Protective coatings for bronze relics should adhere to the basic principles of cultural relic preservation, such as not altering the color and appearance of the artifacts, and being moderately combined with the artifacts to resist erosion due to external environments (such as water and gas). This paper presents the development of a physically crosslinked supramolecular hydrogel produced from guanidinium-based chitosan (GC). The hydrogel exhibits the excellent adsorption protection of bronze, and the addition of clay enhances the water barrier properties of the chitosan film. The supramolecular interaction between sodium polyacrylate/GC/clay confers corrosion buffering capability to the hydrogel coating in corrosive environments, and the gel coating can be self-healing at room temperature for 24 h. The fabricated nanocomposites were comprehensively characterized using various methods (Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, etc.). The electrochemical properties of coated specimens were evaluated, and the impedance spectrum revealed a large impedance arc indicating high charge resistance, which has a corrosion resistance effect.

Tracking the Progression of the Simulated Bronze Disease-A Laboratory X-ray Microtomography Study.

The internal three-dimensional characteristics of X-ray microtomography (micro-CT) has great application potential in the field of bronze corrosion. This work presents a method of simulating bronze disease based on an in situ micro-CT image to study the characteristics of the oxidative hydrolysis reactions of copper(I) chloride and copper(II) chloride dihydrate. A series of high-resolution reconstruction images were obtained by carrying out micro-CT at three key points throughout the experiment. We found that the reactions of copper(I) chloride and copper(II) chloride dihydrate showed different characteristics at different stages of the simulation in the micro-CT view. The method proposed in this work specifically simulated one single type of bronze corrosion and characterized the evolution characteristics of simulated bronze disease. It provides a new perspective to investigate bronze disease and can help improve the subsequent use of micro-CT to distinguish real bronze corrosions.

Correction to "Highly Sensitive Surface-Enhanced Raman Spectroscopy for the Surface Corrosion Analysis of Bronze Relics Using the Polyacrylonitrile/Polyvinylpyrrolidone Silver Nanoparticle Flexible Substrate".

[This corrects the article DOI: 10.1021/acsomega.2c06376.].

Highly Sensitive Surface-Enhanced Raman spectroscopy for the Surface Corrosion Analysis of Bronze Relics Using the Polyacrylonitrile/Polyvinylpyrrolidone Silver Nanoparticle Flexible Substrate.

Surface-enhanced Raman spectroscopy (SERS) is widely used in biological and chemical analyses and in other fields because of its advantages such as high sensitivity and nondestructive nature. Ancient bronze cultural relics of China are exquisitely shaped and highly ornamental. Harmful rust components on the surface of bronze cultural relics have been extensively analyzed. SERS is beneficial to the surface composition analysis of ancient Chinese bronze relics and can be used for accurate characterization with almost zero damage to the surface. In this study, we designed a solution with polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) macromolecules as precursors, which were electrospun and used as the nanofiber substrate. After tannic acid modification, the substrate was loaded with silver nanoparticles by using Tollens' reagent as the silver source and glutaraldehyde as the reducing agent in a water bath. The morphology and size of silver nanoparticles were adjusted by changing the reaction times. The effects of tannic acid and PVP as stabilizers were investigated. R6G and basic copper chloride were used as probe molecules for substrate SERS, and the Raman enhancement factor was calculated. The SERS performance of the substrate with high sensitivity was verified through characterization.

Nickel-Catalyzed Defluorinative Asymmetric Cyclization of Fluoroalkyl-Substituted 1,6-Enynes for the Synthesis of Seletracetam.

The introduction of fluorine-containing groups into organic molecules can significantly affect their physical and chemical properties and has long been used as an effective strategy for drug discovery and development. Consequently, the development of catalytic asymmetric methods for the synthesis of fluorine-containing heterocycles is highly desirable and sought after. Herein, we describe a nickel-catalyzed defluorinative asymmetric cyclization of fluoroalkyl-substituted 1,6-enynes, providing an expedient access to synthetically attractive 4-fluorovinyl-substituted 2-pyrrolidones in good yields with remarkable high levels of chemo-, regio-, and enantioselectivities (90-99 % ee,>35 examples). This protocol features readily available starting materials and excellent functional group compatibility, and exhibits complementary regioselectivity. The utility of this strategy was demonstrated in the enantioselective synthesis of the antiepileptic drug Seletracetam.

Subglacial Meltwater Recharge in the Dongkemadi River Basin, Yangtze River Source Region.

Glaciers on the Tibetan Plateau play an important role in the local hydrological cycle. However, there are only few studies on groundwater in the alpine basins in the Tibetan Plateau which considered the effects of glaciers. Glaciers are extensively distributed in the Dongkemadi River Basin, which is a representative alpine basin in the Yangtze River source region. This study focuses on building a numerical groundwater flow model with glaciations using HydroGeoSphere (HGS) to simulate subglacial meltwater recharge to groundwater in the Dongkemadi River Basin in response to future climate changes. Effects of hydraulic conductivity, precipitation, and temperature on subglacial meltwater recharge to groundwater were discussed. Glacier changes in the future 50 years were predicted under different climate change scenarios. Results show that: (1) the average thickness of the glacier will change significantly; (2) the simulated rate of annual mean subglacial meltwater recharge to groundwater is 4.58 mm, which accounts for 6.33% of total groundwater recharge; and (3) hydraulic conductivity has the largest influence on subglacial meltwater recharge to groundwater, followed by temperature and precipitation. Results of this study are also important to sustainable water resource usage in the Yangtze River source region.

Ni-Catalyzed Reductive Arylcyanation of Alkenes.

We disclose a Ni-catalyzed reductive arylcyanation of alkene using environmentally benign and nontoxic organo cyanating reagent N-cyano-N-phenyl-p-toluenesulfonamide. This reaction provides a new method for the rapid synthesis of cyano-substituted oxindoles and isoquinoline-1,3-diones and features high functional group tolerance. In addition, an enantioselective version was developed for the construction of enantiomerically enriched 3-cyanomethyl oxindole. This method has also been applied to the synthesis of natural alkaloids (+)-esermethole and (+)-physostigmine.

Legionella septentrionalis sp. nov., isolated from aquatic environments in the northern PR China.

Four strains (km711T, km714, km542 and km524), representing a novel Legionella species, were isolated from aquatic environments in northern PR China. Cells were Gram-stain-negative, rod-shaped, microaerobic, motile and growth depended on l-cysteine. They grew at 25‒42 °C (optimum, 35‒37 °C) and could tolerate up to 1.5 % (w/v) NaCl (optimum, 0.5 %). The major fatty acids (>5 %) of the type strain km711T were C17 : 0 anteiso, C15 : 0 anteiso, iso-C16 : 0 and C16 : 1 ω7c and/or iso-C15 : 0 2OH. The pairwise comparison values were <96.1 % for 16S rRNA gene sequences, 23.3‒28.7 % interspecies variation for mip gene sequences, <93.6 % average nucleotide identity and <72.8 % average amino acid identity between these four strains and related type strains within the genus Legionella. The phylogenetic tree based on the four concatenated genes (16S rRNA, mip, rpoB and rnpB) and protein-concatamer tree based on concatenation of 21 protein markers both revealed that these four strains formed a separate phylogenetic branch cluster within the genus Legionella. The results of phenotypic and genotypic features suggest that these four strains represent a novel species of the genus Legionella, for which the name Legionella septentrionalis sp. nov. is proposed (type strain km711T=KCTC 15655T=NBRC 113219T).

Synthesis of bridged tricyclo[5.2.1.01,5]decanes via nickel-catalyzed asymmetric domino cyclization of enynones.

The restricted availability, expense and toxicity of precious metal catalysts such as rhodium and palladium challenge the sustainability of synthetic chemistry. As such, nickel catalysts have garnered increasing attention as replacements for enyne cyclization reactions. On the other hand, bridged tricyclo[5.2.1.01,5]decanes are found as core structures in many biologically active natural products; however, the synthesis of such frameworks with high functionalities from readily available precursors remains a significant challenge. Herein, we report a nickel-catalyzed asymmetric domino cyclization reaction of enynones, providing rapid and modular synthesis of bridged tricyclo[5.2.1.01,5]decane skeletons with three quaternary stereocenters in good yields and remarkable high levels of regio- and enantioselectivities (92-99% ee).

Micro-Drilling of Sapphire using Electro Chemical Discharge Machining.

Electrochemical discharge machining (ECDM) refers to a non-traditional machining method for performing effective material removal on non-conductive hard and brittle materials. To increase the ECDM machining efficiency, traditionally, the method of increasing the machining voltage or increasing the electrolyte concentration is used. These methods can also cause overcut reaming of the drilled holes and a rough surface on the heat affected area. In this study, an innovative combinational machining assisted method was proposed and a self-developed coaxial-jet nozzle was used in order to combine two assisted machining methods, tool electrode rotation and coaxial-jet, simultaneously. Accordingly, the electrolyte of the machining area was maintained at the low liquid level and the electrolyte was renewed at the same time, thereby allowing the spark discharge to be concentrated at the contact surface between the front end of the tool electrode and the machined material. In addition, prior to the machining and micro-drilling, the output of the machining energy assisted mechanism was further controlled and reduced. For the study disclosed in this paper, experiments were conducted to use different voltage parameters to machine sapphire specimens of a 640 µm thickness in KOH electrolyte at a concentration of 5 M.

Stereoselective synthesis of pentasubstituted 1,3-dienes via Ni-catalyzed reductive coupling of unsymmetrical internal alkynes.

The reductive coupling of alkynes represents a powerful strategy for the rapid synthesis of highly substituted 1,3-dienes. This method has the advantages of high atom and step economy, and readily available substrates. Unfortunately, the intermolecular coupling of unsymmetrical internal alkynes remains extremely challenging due to the difficulty in controlling self-dimerization and cross-coupling, as well as stereo- and regioselectivity. Previous reports are still limited to intramolecular processes or the use of stoichiometric amounts of metal catalyst. Herein, we report that nickel-catalyzed reductive coupling of two unsymmetrical internal alkynes can overcome the above-mentioned limitations by using a hemilabile directing group strategy to control the regioselectivity. A series of synthetically challenging penta-substituted 1,3-dienes are obtained in good yields with high regio- and enantioselectivity (mostly > 20/1 rr, >90% ee).

[Evaluation of dietary intake quantity and quality of high school students in Shanghai City].

OBJECTIVE: To understand the dietary intake quantity and quality of high school students in Shanghai education. METHODS: From 2015 to 2016, Shanghai center for Disease Control and Prevention, divided the school into three levels(urban area, suburban area and rural area) according to the economic level and population composition of the street where the school was located. The probability-proportional-to-size sampling technique was used to select 19 high schools, from which 9 boys and 9 girls from same class were randomly recruited for each grade. A total of 1026 students were recruited. The survey included general situation questionnaire and dietary inquiry. Participants were required to complete the standardized questionnaire form through face-to-face interviews with trained interviewers. Chinese Dietary Guidelines(2016) was used to evaluate dietary quantity while China healthy diet index(CHDI) was used to evaluate dietary quality. RESULTS: The medians of intake of grain, vegetables, fruits, meat/livestock, fish/shrimp, eggs, milk and milk products, bean and bean products, cooking oil, cooking salt were 313. 8, 189. 7, 66. 3, 179. 2, 34. 7, 48. 9, 133. 3, 33. 3, 27. 1 and 6. 0 g/d within high school students, respectively. In both boys and girls, the medians of intake of vegetables, fruits, fish/shrimp, dairy products were lower than reference standard and meat/livestock was higher(P<0. 05). The intake differences among different area's high school students upon grain, vegetables, fruits, poultry/livestock, fish/shrimp, dairy products, beans/nuts, cooking oil, cooking salt were statistically significant(P<0. 05). The CHDI median total score of high school students was 68. 5 in Shanghai. 75. 2% of the CHDI total scores were between 60 and 80. The vegetable score, dark vegetable score, fruit score and total CHDI score in boys were significantly lower than those in girls(P<0. 05). The urban area CHDI score was significantly higher than suburban's and countryside's(P<0. 05). CONCLUSION: Both dietary structure and dietary quality are inappropriate and unfit within high school students in Shanghai, the urban area's condition is better than another two. We suggest to increase intake of vegetables, fruits, fish/shrimp, dairy products while decrease poultry/livestock's consumption.

MicroRNA-133 inhibits the growth and metastasis of the human lung cancer cells by targeting epidermal growth factor receptor.

PURPOSE: Accounting for 25% of all cancers and 20% of the cancer related-mortality, lung cancer is one of the devastating types of malignancies. The main obstacles for successful lung cancer manipulation include late diagnosis, dearth of safer chemotherapy and lack of potent therapeutic targets. Evidence indicates that microRNAs (miRs) may prove essential therapeutic targets for the management of deadly diseases, including cancer. Herein the role of miR-133 was investigated in lung cancer and the therapeutic potential of miR-133 was explored. METHODS: qRT-PCR was used for expression profiling of miR-133 and epithermal growth factor receptor (EGFR) in normal lung cell line MRC5 and lung cancer cell lines SK-MES-1, A549, A427 and DMS-53. Cell Counting Kit-8 (CCK8) assay was used to monitor the proliferation rate. Flow cytometry was used for cell cycle analysis. Apoptosis was examined by DAPI and annexin V/propidium iodide (PI) staining. TargetScan analysis was performed to identify the potential target of miR-133 and western blot analysis was done to estimate the proteins' expression. RESULTS: miR-133 was significantly (p<0.05) downregulated in lung cancer. Overexpression of miR-133 in A549 lung cancer cells caused significant (p<0.05) inhibition of their proliferation via activation of apoptotic cell death, suggestive of the tumor suppressive role of miR-133. In addition, miR-133 overexpression also resulted in significant (p<0.05) suppression of A549 cell migration and invasion. TargetScan analysis indicated EGFR to be the potential target of miR-133 in A549 cells. Analysis of EGFR expression in lung cancer cell lines showed up to 4.6 fold upregulation of EGFR. However, miR-133 overexpression resulted in downregulation of EGFR expression. Furthermore, silencing of EGFR also resulted in inhibition of proliferation, migration and invasion of A549 cells. However, overexpression of EGFR could nullify the tumor suppressive effects of miR-133, indicating EGFR inhibition is essential for the miR-133-mediated inhibitory effects on A549 cell proliferation. CONCLUSION: Taken together, miR-133 acts as a tumor suppressor and may prove essential in the management of lung cancer.

Characteristic Changes of Astrocyte and Microglia in Rat Striatum Induced by 3-NP and MCAO.

Our previous studies had confirmed that both 3-NP and MCAO induced the behavioral defect as well as striatal neuronal injury and loss in experimental rats. This study aimed to examine different response forms of striatal astrocyte and microglia in 3-NP and MCAO rat models. The present results showed that the immunoreaction for GFAP was extremely weak in the lesioned core of striatum, but in the transition zone of 3-NP model and the penumbra zone of MCAO model, GFAP+ cells showed strong hypertrophic and proliferative changes. Statistical analysis for the number, size and integral optical density (IOD) of GFAP+ cells showed significant differences when compared with their controls and compared between the core and the transition zone or the penumbra zone, respectively, but no differences between the 3-NP and MCAO groups. However, Iba-1+ cells showed obvious hypertrophy and proliferation in the injured striatum in the 3-NP and the MCAO models, especially in the transition zone of 3-NP model and the penumbra zone of MCAO model. These Iba-1+ cells displayed two characteristic forms as branching cells with thick processes and amoeboid cells with thin processes. Statistical analysis showed that the number, size and IOD of Iba-1+ cells were significantly increased in the cores and the transition zone of 3-NP group and the penumbra zone of MCAO group than that of the controls, and the immune response of Iba-1 was stronger in the MCAO group than in the 3-NP group. The present results suggested that characteristic responses of astrocyte and microglia in the 3-NP and the MCAO models display their different effects on the pathological process of brain injury.

Syndrome Differentiation Analysis on Mars500 Data of Traditional Chinese Medicine.

Mars500 study was a psychological and physiological isolation experiment conducted by Russia, the European Space Agency, and China, in preparation for an unspecified future manned spaceflight to the planet Mars. Its intention was to yield valuable psychological and medical data on the effects of the planned long-term deep space mission. In this paper, we present data mining methods to mine medical data collected from the crew consisting of six spaceman volunteers. The synthesis of the four diagnostic methods of TCM, inspection, listening, inquiry, and palpation, is used in our syndrome differentiation. We adopt statistics method to describe the syndrome factor regular pattern of spaceman volunteers. Hybrid optimization based multilabel (HOML) is used as feature selection method and multilabel k-nearest neighbors (ML-KNN) is applied. According to the syndrome factor statistical result, we find that qi deficiency is a base syndrome pattern throughout the entire experiment process and, at the same time, there are different associated syndromes such as liver depression, spleen deficiency, dampness stagnancy, and yin deficiency, due to differences of individual situation. With feature selection, we screen out ten key factors which are essential to syndrome differentiation in TCM. The average precision of multilabel classification model reaches 80%.