Covalent Organic Frameworks with Tunable Chirality for Chiral-Induced Spin Selectivity.

Chiral covalent organic frameworks (CCOFs) have attracted extensive interest for their potential applications in various enantioselective processes. However, the exploitation of chirality-induced spin selectivity (CISS) that enables a new technology for the injection of spin polarized current without the need for a permanent magnetic layer within CCOFs remains a largely untapped area of research. Here, we demonstrate that, for the first time, COFs can be an attractive platform to develop spin filter materials with efficient CISS. This facilitates the design and synthesis of a new family of Zn(salen)-based 2D CCOFs, namely, CCOFs-9-12, by imine condensation of chiral 1,2-diaminocyclohexane and tri- or tetra(salicylaldehyde) derivatives. CCOF-9, distinguished by its unique C2 symmetric "armchair" tetrasubstituted pyrene conformation, exhibits the most pronounced chirality among these materials and serves as a solid-state host, enabling the enantioselective adsorption of racemic drugs with an enantiomeric excess (ee) of up to 97%. After substituting diamagnetic zinc(II) ions for paramagnetic cobalt(II), the resulting CCOF-9-Co not only retains its high crystallinity, porosity, and exceptional chirality but also exhibits enhanced conductivity, a crucial factor for the effective observation of CISS. Magnetic conductive atomic force microscopy showed that CCOF-9-Co exhibited a remarkable CISS effect with up to an 88-94% spin polarization ratio. This phenomenon is further confirmed by the increased intensity in the magnetic circular dichroism (MCD) when CCOF-9-Co is under an external magnetic field. This work therefore shows the tremendous potential of CCOFs for controlling spin selectivity and will stimulate the creation of new types of crystalline polymers with strong CISS effects for spin filters.

Crystalline Polyphenylene Covalent Organic Frameworks.

The synthesis of crystalline polyphenylene covalent organic frameworks (COFs) was accomplished by linking fluorinated tris(4-acetylphenyl)benzene building units using aldol cyclotrimerization. The structures of the two COFs, reported here, were confirmed by powder X-ray diffraction techniques, Fourier transform infrared, and solid-state 13C CP/MAS NMR spectroscopy. The results showed that the COFs were porous and chemically stable in corrosive, harsh environments for at least 1 week. Accordingly, postsynthetically modified derivatives of these COFs using primary amines showed CO2 uptake from air and flue gas.

Activating the healing process: three-dimensional culture of stem cells in Matrigel for tissue repair.

BACKGROUND: To establish a strategy for stem cell-related tissue regeneration therapy, human gingival mesenchymal stem cells (hGMSCs) were loaded with three-dimensional (3D) bioengineered Matrigel matrix scaffolds in high-cell density microtissues to promote local tissue restoration. METHODS: The biological performance and stemness of hGMSCs under 3D culture conditions were investigated by viability and multidirectional differentiation analyses. A Sprague‒Dawley (SD) rat full-thickness buccal mucosa wound model was established, and hGMSCs/Matrigel were injected into the submucosa of the wound. Autologous stem cell proliferation and wound repair in local tissue were assessed by histomorphometry and immunohistochemical staining. RESULTS: Three-dimensional suspension culture can provide a more natural environment for extensions and contacts between hGMSCs, and the viability and adipogenic differentiation capacity of hGMSCs were significantly enhanced. An animal study showed that hGMSCs/Matrigel significantly accelerated soft tissue repair by promoting autologous stem cell proliferation and enhancing the generation of collagen fibers in local tissue. CONCLUSION: Three-dimensional cell culture with hydrogel scaffolds, such as Matrigel, can effectively improve the biological function and maintain the stemness of stem cells. The therapeutic efficacy of hGMSCs/Matrigel was confirmed, as these cells could effectively stimulate soft tissue repair to promote the healing process by activating the host microenvironment and autologous stem cells.

Dynamic accuracy measurement method for star trackers using a time-synchronized high-accuracy turntable.

Star trackers are typically used in a spacecraft to provide absolute attitude information to the on-board attitude control system so as to promote high accuracy. The performance of the star tracker is rather important. Attitude incorrectness provided by star trackers may lead to bad navigation with big deviations, even failure of satellites. Therefore, how to realize and verify the accuracy is crucial. As a matter of fact, it is difficult to validate accuracy of star trackers on the ground, especially for star trackers under highly dynamic conditions. In this paper, an accuracy measurement method for star trackers under dynamic conditions is proposed, utilizing a high-accuracy swing table to provide reference to compare. To this end, a swing table, star tracker, and the test equipment are synchronized, in order to reduce systematic errors. As the motion trajectory of the swing table can be set beforehand, the initial attitude of the star tracker can be predicted through a set of coordinate transformations. As a result, the star tracker is able to keep tracking, regardless of the angular velocity of the swing table. This makes the statistical sample points more sufficient and the results more reliable. Moreover, it can evaluate the angular velocity of star trackers up to 20°/s. In comparison with the conventional method with simulated stars, this method utilizes real navigation stars as observation targets making the measurement results much closer to the on-orbit performance. Lastly, but much more importantly, it can also verify the performance of a star tracker in one experiment, such as sensitivity, static performance, capture probability, and so on. Experimental results demonstrate that the proposed method is effective, especially for highly dynamic star trackers. Such a measurement environment is close to the in-orbit conditions, and it can satisfy the stringent requirement for star trackers under high dynamics.

First Report of Lecanicillium aphanocladii Causing Rot of Sparassis crispa in China.

Sparassis crispa, also known as cauliflower mushroom, is a new popularly edible mushroom in China, also a medicinal mushroom, which possesses various biological activities, such as immunopotentiation, anti-diabetes, anti-cancer, and anti-inflammatory effects. (Han et al., 2018). In recent years, the artificial cultivation of S. crispa has gained considerable public attention in China. In 2023, approximately 20% of S. crispa (about 0.05 ha of the planting area) showed obvious rot with white molds symptoms in mushroom hothouse, located in Shuangliu county, Sichuan province, China (GPS, 104°7'51"N, 30°25'2"E). Infected fruiting bodies were covered by white mycelia that later turned red or fuchsia. In the final stages of infection, the S. crispa fruiting bodies turned dark red or brown before rotting. The pathogen was isolated from the margin of the lesions by plating onto potato dextrose agar (PDA), and incubated at 25℃ in the dark for a week. Five pure culture fungal isolates were obtained. Collected isolates with similar morphology were described as Lecanicillium spp. (Zare et al., 2001). The colonies were raised, covered with white, the reverse side were violet brown, produced diffusing reddish-purple pigment. Conidiogenous cells produced singly, in pairs, verticillate or in dense irregular clusters on prostrate hyphae, at first flask-shaped, tapering into threadlike neck, with a size of 3.0-6.2×0.8-2.2 µm. Conidia were solitary, oval to subglobose, and 2.3-4.0×1.1-2.1 µm in size, similar to L. aphanocladii (Higo et al., 2021). For pathogenicity testing, ten fruiting bodies of S. crispa (planted in the bottles) were selected. Fungal cake of the isolate Bx-Ljb of L. aphanocladii were applied to the fruiting body of S. crispa, whereas pieces of sterile PDA medium were used as controls. All the bottles were incubated at 19±1℃, 85-100% relative humidity, and 18 h of light in the mushroom hothouse. A week later, the inoculated fruiting bodies developed brown spots and gradually expanding, with symptoms similar to the original diseased fruiting bodies. The controls remained healthy. The same fungus was reisolated from the infected fruiting bodies and subsequently identified by morphological characteristics and DNA sequence analysis. The pathogenicity test was repeated three times with similar results. For molecular identification, the DNA of the isolates was extracted using a Fungi Genomic DNA Extraction kit (Solarbio, Beijing). The SSU, LSU, and TEF1-α genes were amplified with the primer as previously described (Zhou et al., 2018). The generated sequences were deposited in GenBank with accession numbers OR206377, OR206378, and OR204702, respectively. BLASTn analyses showed >99.2% identity with previously deposited sequences of L. aphanocladii. Based on the maximum likelihood method, phylogenetic analysis revealed 99% bootstrap support values with L. aphanocladii. The fungus was identified as L. aphanocladii based on morphological and multilocus phylogenetic analyses. To our knowledge, there are two reports of L. aphanocladii on fruiting bodies of Tremella fuciformis and Morchella sextelata in China, and this is the first report of this fungus causing rot of S. crispa in China. It may be a reminder that the risk of L. aphanocladii in mushroom production in China is gradually increasing. These results will contribute to developing managemental strategies for this disease in S. crispa.

First Report of Sphingobacterium multivorum Causing Bacterial Rot of Cauliflower mushroom (Sparassis latifolia) in China.

Cauliflower mushroom (Sparassis latifolia), is widely distributed in Australia, North America, Europe, and East Asia (Bashir et al., 2020). It is known for its medicinal significance due to the availability of various pharmacological substances and their use in health supplements (Bashir et al., 2017). In recent years, with the development of artificial cultivation technology, S. latifolia has been industrialized in China, with an annual output value 50 million dollars. In March 2023, approximately 15% of S. latifolia showed obvious bacterial rot in mushroom hothouse (about 0.05 ha), located in Shuangliu county, Sichuan province, China (104°7'51"N, 30°25'2"E). The affected parts appear water-soaked, and become sunken and softened as the disease progresses. In the finally, all the fruiting body tissues turn into paste, with colors pale yellow, and have a foul smell. The pathogen was isolated from the margin of the lesions by dilution and streaking techniques onto Nutrient Agar, and incubated at 28℃ in the dark for 2-3 days. A single colony was re-streak for purification. Eight isolates were obtained from five samples collected randomly. The representative three isolates were selected for further characterization. For pathogenicity testing, ten health fruit bodies of S. latifolia were selected (for per isolate). Bacterial suspensions (1 × 107 CFU/ml) of the three isolates were applied to the fruiting body until wet, sterile water was used as controls. All the S. latifolia were maintained at 19±1℃, 85-100% relative humidity, and 18 h of light in the mushroom hothouse. Three days later, the inoculated fruiting bodies developed yellow color, and appear water-soaked, five days later, fruiting body gradually turn to soft and part turn to rot, seven days later, the fruiting body tissues completely turn into paste with a foul smell. The symptoms exhibited were similar to those of the original diseased fruiting bodies, while the control group remained healthy. The same bacterial were re-isolated from the infected fruiting bodies and subsequently identified by morphological characteristics and DNA sequenced. The pathogenicity test was conducted three times, each yielding similar results. The colonies of the pathogen are gram-negative rods, medium sized, convex, smooth, opaque, turning yellow after several days at a temperature 28℃. For molecular identification, the DNA of the representative three isolates was extracted using a Bacterial Genomic DNA Extraction Kit (Solarbio, Beijing). The 16S rRNA genes were amplified and sequenced with the primer 27F/1492R (Lane et al., 1985). Finally, the sequences were identical. The generated representative sequence was deposited in GenBank with accession number OR399122. BLASTn analysis showed 100% identity (1404/1404 bp) with previously deposited sequence (accession number CP068224) of S. multivorum FDAARGOS in GenBank. Based on the maximum likelihood method, phylogenetic analysis revealed 100% bootstrap support values with S. multivorum. Finally, the bacterium was identified as S. multivorum. This is the first report of S. multivorum causing bacterial rot of mushroom. The fruiting body of S. multivorum consists of multiple folded flat lobes, which are thin and have large surface area, may facilitate the infection of S. multivorum. Sphingobacterium sp. are named for their synthesize sphingolipids, which play an important role in bacterial infection (Kunz et al., 2019). These results will contribute to developing control strategies for this disease.

Directing Molecular Weaving of Covalent Organic Frameworks and Their Dimensionality by Angular Control.

Although reticular chemistry has commonly utilized mutually embracing tetrahedral metal complexes as crossing points to generate three-dimensional molecularly woven structures, weaving in two dimensions remains largely unexplored. We report a new strategy to access 2D woven COFs by controlling the angle of the usually linear linker, resulting in the successful synthesis of a 2D woven pattern based on chain-link fence. The synthesis was accomplished by linking aldehyde-functionalized copper(I) bisphenanthroline complexes with bent 4,4'-oxydianiline building units. This results in the formation of a crystalline solid, termed COF-523-Cu, whose structure was characterized by spectroscopic techniques and electron and X-ray diffraction techniques to reveal a molecularly woven, twofold-interpenetrated chain-link fence. The present work significantly advances the concept of molecular weaving and its practice in the design of complex chemical structures.

Oxidative stress mediates the impact of heatwaves on survival, growth and immune status in a lizard.

Climate change often includes increases in the occurrence of extreme environmental events. Among these, heatwaves affect the pace of life and performance of wildlife, particularly ectothermic animals, owing to their low thermoregulatory abilities. However, the underlying mechanisms by which this occurs remain unclear. Evidence shows that heatwaves alter the redox balance of ectotherms, and oxidative stress is a major mediator of life-history trade-offs. Therefore, oxidative stress may mediate the effect of extreme thermal conditions on the life histories of ectotherms. To test this hypothesis, a 2 × 2 experiment was conducted to manipulate the redox balance (through a mitochondrial uncoupler that alleviates oxidative stress) of the desert toad-headed agama (Phrynocephalus przewalskii) exposed to heatwave conditions. We recorded lizard growth and survival rates and quantified their redox and immune statuses. In control lizards (unmanipulated redox balance), heatwave conditions decreased growth and survival and induced oxidative damage and immune responses. By contrast, lizards with alleviated oxidative stress showed close-to-normal growth, survival, and immune status when challenged with heatwaves. These results provide mechanistic insight into the role of oxidative stress in mediating the effects of extreme temperatures on ectothermic vertebrates, which may have major eco-evolutionary implications.

Different nitrogen saturation thresholds for above-, below-, and total net primary productivity in a temperate steppe.

Identifying the thresholds for the positive responses of total net primary productivity (NPP) to nitrogen (N) enrichment is an essential prerequisite for predicting the benefits of N deposition on ecosystem carbon sequestration. However, the responses of below-ground NPP (BNPP) to N enrichment are unknown in many ecosystems, which limits our ability to understand the carbon cycling under the scenario of increasing N availability. We examined the changes in above-ground NPP (ANPP), BNPP, and NPP of a temperate meadow steppe across a wide-ranging N addition gradient (0, 2, 5, 10, 20, and 50 g N m-2 year-1 ) during 5 years. Both ANPP and NPP increased nonlinearly with N addition rates. The N saturation threshold for ANPP (TA ) and NPP (TN ) was at the rate of 13.11 and 6.70 g N m-2 year-1 , respectively. BNPP decreased with increasing N addition when N addition rates ˃5 g N m-2 year-1 , resulting in much lower TN than TA . Soil N enrichment played a key role in driving the negative impacts of high N addition rates on BNPP, and consequently on the earlier occurrence of N saturation threshold for NPP. Our results highlight the negative effects of soil N enrichment on NPP in natural grasslands super-saturated with N. Furthermore, by considering ANPP and BNPP simultaneously, our results indicate that previous findings from above-ground might have over-estimated the positive effects of N deposition on primary productivity.

Laser-reduced graphene oxide for a flexible liquid sliding sensing surface.

Flexible electronic skin is a flexible sensor system that imitates human skin. Recently, flexible sensors have been successfully developed. However, the droplet sliding sensing technology on a flexible electronic skin surface is still challenging. In this Letter, a flexible droplet sliding sensing surface is proposed and fabricated by laser-reduced graphene oxide (LRGO). The LRGO shows porous structures and low surface energy, which are beneficial for infusing lubricants and fabricating stable slippery surfaces. The slippery surface guarantees free sliding of droplets. The droplet sliding sensing mechanism is a combination of triboelectricity and electrostatic induction. After a NaCl droplet slides from lubricant-infused LRGO, a potential difference (∼0.2 mV) can be measured between two Ag electrodes. This study reveals considerable potential applications in intelligent robots and the medical field.

Fabrication and application of carbohydrate microarray for analyzing human serum antibody-carbohydrate interaction.

We introduced a strategy for preparing a carbohydrate microarray and demonstrated its utility for characterizing carbohydrate binding and activities. We isolated the lipopolysaccharide (LPS) components from different bacteria and explored the possibility of immobilizing these glycoconjugates on a high-binding polystyrene plate. Carbohydrate-specific combination was examined by observing the binding of the blood group B analogic LPS O-polysaccharide from Escherichia coli on the high-binding polystyrene plate and anti-B from a broad spectra antibody of human blood serum. Strong binding of antibodies was screened, as it was evident that relative response value is two times higher than control. The hybridization results indicated that this method is a reliable technique for the detection of human intestinal bacteria and is expected to be applied in diagnostics and seroepidemiology.

First Report of Leaf blight Caused by Colletotrichum karstii on Banana Shrub (Michelia figo) in Sichuan, China.

Banana Shrub (Michelia figo (Lour.) Spreng.) is widely cultivated in most of southern China (Wu et al, 2008). It can be used to make essential oil and flower tea（Ma et al, 2012; Li et al, 2010）.The first symptoms were observed in Sept. 2020 at a grower's field in Banana shrub seedlings (0.6 ha), Ya'an city (29°30'N, 102°38'E), Hanyuan county. The symptoms re-occurred in May-June of 2021 and became prevalent from August to September. the incidence rate and the disease index were 40% and 22%, respectively. Initially, purplish-brown necrotic lesions appeared at the leaf tip with dark-brown edges. Progressively, necrosis spread, to the middle of the leaves, and the older area turned gray-white. Dark sunken lesions appeared in the necrotic areas and orange conidial masses were visible under humid conditions. Ten isolates were obtained on potato dextrose agar (PDA) from 10 leaf samples using previously described tissue isolation method (Fang et al. 1998). All the 10 isolates exhibited similar morphological characteristics. Grey to white aerial mycelium at the center and in dispersed tufts, with numerous dark conidiomata scattered over the surface, reverse was pale orange with numerous dark flecks corresponding to the ascomata, orange conidial masses were formed from mature conidiomata. Conidia were hyaline, smooth-walled, aseptate, straight, cylindrical, apex round, the contents appearing granular 14.8 to 17.2 × 4.2 to 6.4 µm (average: 16.26 × 4.84 µm, n=30) as Colletotrichum spp. (Damm et al. 2012). For molecular identification, DNA was extracted from a representative isolate HXcjA using a plant genomic DNA extraction kit (Solarbio, Beijing). and the partial sequences of internal transcribed spacer region (ITS, OQ641677), glyceraldehyde-3-phosphate dehydrogenase (GAPDH, OL614009), actin (ACT, OL614007), beta-tubulin (TUB2, OL614011), histone3 (HIS3, OL614010), and calmodulin (CAL, OL614008) were amplified and sequenced using the primer pairs ITS1/ITS4 (White et al. 1990), GDF/GDR (Templeton et al. 1992), ACT-512F/ACT-783R, CAL 228F/CAL 737R (Carbone et al. 1999), TUB1F/Bt2bR, CYLH3F/CYLH3R (Crous et al. 2004), respectively. BLASTn analysis for ITS, GAPDH, CAL, ACT, TUB2 and HIS3 sequences showed ≥99.7% identity to C. Karstii, namely, NR_144790 (532/532 bp), MK963048 (252/252 bp), MK390726 (431/431 bp), MG602039 (761/763 bp), (KJ954424, 294/294 bp), (KJ813519, 389/389 bp), respectively. The fungus was identified as C. karstii based on morphology and a multigene phylogeny. The conidial suspension (1 × 107 conidia/mL) with 0.05% Tween 80 buffer was used for pathogenicity test, by spraying 2-year-old Banana Shrub plants. Ten plants were inoculated with spore suspensions (approximately 2ml per plant). An equal number of plants were sprayed with 0.05% Tween 80 buffer to serve as a control. Fifteen days later, the inoculated plants showed similar symptoms as the original diseased plants but the controls remained asymptomatic. C. karstii was re-isolated from the infected leaves and identified by morphology and a multigene phylogeny. The pathogenicity test was repeated three times with similar results, confirming Koch's postulates. To our knowledge, this is the first report of Banana Shrub leaf blight caused by C. karstii in China. This disease reduces the ornamental and economic value of Banana Shrub, and this work will provide a basis for the prevention and treatment of the disease in the future.

Efficacy and Safety of Transplantation of Autologous Fat, Platelet-Rich Plasma (PRP) and Stromal Vascular Fraction (SVF) in the Treatment of Acne Scar: Systematic Review and Meta-analysis.

BACKGROUND: The efficacy and safety evaluation of the transplantation of autologous fat, platelet-rich plasma (PRP) and stromal vascular fraction (SVF) in acne scars has not been completely unified. This article will analyze and process the data of the included studies through evidence-based medicine to evaluate the efficacy and safety of autologous fat grafting, PRP and SVF for acne scar treatment, so as to provide treatment basis and strategy for the clinical treatment of acne scars. METHODS: We searched the PubMed, Embase, Cochrane Library databases, CNKI, Wanfang and CQVIP databases for studies published during the time between the establishment of the databases through October 2022. We included studies that report autologous fat grafting, SVF and PRP for patients with acne scars. We excluded repeated publication, researches without full text, incomplete information or inability to conduct data extraction and animal experiments, case report, reviews and systematic reviews. STATA 15.1 software was used to analyze the data. RESULTS: The findings showed that fat grafting had excellent improvement, marked improvement, moderate improvement and mild improvement rates of 36%, 27%, 18% and 18%, respectively, PRP had excellent improvement, marked improvement, moderate improvement and mild improvement rates of 0%, 26%, 47% and 25%, respectively, and the SVF had excellent improvement, marked improvement, moderate improvement and mild improvement rates of 73%, 25%, 3% and 0%, respectively. Additionally, the pooled results showed that there was no significant difference between PRP treatment and pre-treatment in Goodman and Baron scale score. However, Shetty et al. reported that Goodman and Baron scale score after fat grafting was significantly lower than pre-treatment. The results also showed that after fat grafting treatment, incidence of pain after fat grafting was 70%. After PRP treatment, in addition to pain (17%), there is a higher probability of postinflammatory hyperpigmentation (17%) and hematoma (6%). After SVF treatment, the incidence of postinflammatory hyperpigmentation and hematoma was all 0%. CONCLUSION: Autologous fat grafting, PRP and SVF are effective for the treatment of acne scars, and the safety of autologous fat grafting, PRP and SVF is acceptable. Autologous fat grafting and SVF may be a better treatment for acne scars than PRP. However, this hypothesis still needs to be tested in the future large randomized controlled trials. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Transcriptomics Reveals the Effect of Short-Term Freezing on the Signal Transduction and Metabolism of Grapevine.

Low temperature is an important factor limiting plant growth. Most cultivars of Vitis vinifera L. are sensitive to low temperatures and are at risk of freezing injury or even plant death during winter. In this study, we analyzed the transcriptome of branches of dormant cv. Cabernet Sauvignon exposed to several low-temperature conditions to identify differentially expressed genes and determine their function based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG)enrichment analyses. Our results indicated that exposure to subzero low temperatures resulted in damage to plant cell membranes and extravasation of intracellular electrolytes, and that this damage increased with decreasing temperature or increasing duration. The number of differential genes increased as the duration of stress increased, but most of the common differentially expressed genes reached their highest expression at 6 h of stress, indicating that 6 h may be a turning point for vines to tolerate extreme low temperatures. Several pathways play key roles in the response of Cabernet Sauvignon to low-temperature injury, namely: (1) the role of calcium/calmodulin-mediated signaling; (2) carbohydrate metabolism, including the hydrolysis of cell wall pectin and cellulose, decomposition of sucrose, synthesis of raffinose, and inhibition of glycolytic processes; (3) the synthesis of unsaturated fatty acids and metabolism of linolenic acid; and (4) the synthesis of secondary metabolites, especially flavonoids. In addition, pathogenesis-related protein may also play a role in plant cold resistance, but the mechanism is not yet clear. This study reveals possible pathways for the freezing response and leads to new insights into the molecular basis of the tolerance to low temperature in grapevine.

UPLC-MS/MS Method for Detection of Etomidate and Its Metabolite Etomidate Acid Quantity in Blood.

OBJECTIVES: To establish a method for the simultaneous quantitative analysis of etomidate and its metabolite etomidate acid in blood, and to discuss its application value in actual cases. METHODS: Acetonitrile precipitate protein method was used, and C18 column was selected. Gradient elution was performed with acetonitrile and 5 mmol/L ammonium acetate within 6 min. Electrospray ionization source in positive ion mode was used. The internal standard etomidate acid-d5 was obtained by etomidate-d5 alkaline hydrolysis reaction. Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used for quantitative analysis. The methodological verification was conducted. RESULTS: Etomidate and etomidate acid in blood showed good linear relationship in the quantitative linear range (r>0.999), with the lower limit of quantification was 2.5 ng/mL and 7.5 ng/mL, respectively. The accuracy, precision, recovery rate, and matrix effect of the method met the professional verification standards. The practical application results showed that etomidate and etomidate acid could be detected in the blood of the abusers, and their mass concentrations ranged from 17.24 to 379.93 ng/mL. CONCLUSIONS: The method established in this study can simultaneously quantify etomidate and etomidate acid in blood, which is simple and convenient to operate with accuracy. It can meet the detection needs of actual cases and provide technical support for law enforcement to crack down on etomidate abuse.

Low expression of exosomal miR-150 predicts poor prognosis in colorectal cancer patients after surgical resections.

Liver metastasis is a leading indicator of poor prognosis in patients with colorectal cancer (CRC). Exosomal intercellular communication has been reported to play an important role in cancer invasion and metastasis. Here, we characterized exosomal miRNAs underlying liver metastasis in CRC patients (Cohort 1, n = 30) using miRNA arrays. Exosomal miR-150 was found to be downregulated in CRC patients with liver metastases compared to those without (P = 0.025, fold change [FC] = 2.01). These results were then validated using another independent cohort of CRC patients (Cohort 2, n = 64). Patients with low expression of exosomal miR-150 had significantly shorter overall survival (OS) time (33.3 months versus 43.3 months, P = 0.002). In addition, the low expression of exosomal miR-150 was significantly correlated with advanced tumor node metastasis staging (P = 0.013), higher CA199 level (P = 0.018), and the presence of liver metastasis (P = 0.048). Multivariate analysis showed that low expression of exosomal miR-150 (P = 0.035) and liver metastasis (P < 0.001) were independent prognostic factors for overall survival. In vivo and in vitro studies showed that the viability and invasion of CRC cells were both significantly suppressed by ExomiR-150. Target-prediction assessment and dual-luciferase reporter assay indicated that FTO (the fat mass and obesity-associated gene) was a direct target for miR-150. This study first demonstrated that exosomal miR-150 may be a potential prognostic factor and treatment target for CRC.

2D Covalent Organic Frameworks with cem Topology.

A large number of covalent organic frameworks (COFs) with two-dimensional (2D) layered structures have been reported, but their network structures are restricted to only seven topologies (namely, hcb, hxl, kgm, sql, tth, bex, and kgd) because of the limited choice of building blocks. In this work, we illustrate how linking pseudo-fivefold symmetric 1,2,3,4,5-penta(4-formylphenyl)pyrrole with linear aromatic diamines through dynamic imine bonds produces three 2D porous COFs with an unprecedented cem topology, which represent the first examples of five-vertex semiregular Archimedean tessellations in COFs. The three 2D COFs are isostructural, and each adopts an eclipsed stacking structure with unidirectional hierarchical pores, in which the pyrrole unit is utilized as the five-vertex of network to form both square and triangular pores in a 33.42 sequence. With high thermal and chemical resistances, the COF-packed HPLC columns show excellent performance to provide separation of 10 different polycyclic aromatic hydrocarbons, a group of the most widespread organic environmental pollutants. The implementation of five-vertex Archimedean tessellations thus couriers a strategy to design COFs with new topologies and paves a new way to expand the inimitable properties of COF materials.

Entanglement of Square Nets in Covalent Organic Frameworks.

Two entangled 2D square covalent organic frameworks (COFs) have been synthesized from 4,4',4″,4‴-(9,9'-spirobi[fluorene]-2,2',7,7'-tetrayl)-tetrabenzaldehhyde (SFTB) and p-phenylenediamine (PPA) and benzidine (BZD) to form COF-38, [(SFTB)(PPA)2]imine, and its isoreticular form COF-39, [(SFTB)(BZD)2]imine. We also report the single-crystal electron diffraction structure of COF-39 and find that it is composed of mutually entangled 2D square nets (sql). These COFs represent the first examples of entangled 2D COF structures, which, as we illustrate, were made possible by our strategy of using the distorted tetrahedral SFTB building unit. SFTB overcomes the propensity of 2D COFs to stack through π-π stacking and allows entanglements to form. This work significantly adds to the design principles of COFs.

Droplet Bouncing: Fundamentals, Regulations, and Applications.

Droplet impact is a ubiquitous phenomenon in nature, daily life, and industrial processes. It is thus crucial to tune the impact outcomes for various applications. As a special outcome of droplet impact, the bouncing of droplets keeps the form of the droplets after the impact and minimizes the energy loss during the impact, being beneficial in many applications. A unified understanding of droplet bouncing is in high demand for effective development of new techniques to serve applications. This review shows the fundamentals, regulations, and applications of millimeter-sized droplet bouncing on solid surfaces and same/miscible liquids (liquid pool and another droplet). Regulation methods and current applications are summarized, and potential directions are proposed.

Decoupled responses of above- and below-ground stability of productivity to nitrogen addition at the local and larger spatial scale.

Temporal stability of net primary productivity (NPP) is important for predicting the reliable provisioning of ecosystem services under global changes. Although nitrogen (N) addition is known to affect the temporal stability of aboveground net primary productivity (ANPP), it is unclear how it impacts that of belowground net primary productivity (BNPP) and NPP, and whether such effects are scale dependent. Here, using experimental N addition in a grassland, we found different responses of ANPP and BNPP stability to N addition at the local scale and that these responses propagated to the larger spatial scale. That is, N addition significantly decreased the stability of ANPP but did not affect the stability of BNPP and NPP at the two scales investigated. Additionally, spatial asynchrony of both ANPP and BNPP among communities provided greater stability at the larger scale and was not affected by N addition. Our findings challenge the traditional view that N addition would reduce ecosystem stability based on results from aboveground dynamics, thus highlighting the importance of viewing ecosystem stability from a whole system perspective.