Unveiling the effect of Ni on the formation and structure of Earth's inner core.

Ni is the second most abundant element in the Earth's core. Yet, its effects on the inner core's structure and formation process are usually disregarded because of its electronic and size similarity with Fe. Using ab initio molecular dynamics simulations, we find that the bcc phase can spontaneously crystallize in liquid Ni at temperatures above Fe's melting point at inner core pressures. The melting temperature of Ni is shown to be 700 to 800 K higher than that of Fe at 323 to 360 GPa. hcp, bcc, and liquid phase relations differ for Fe and Ni. Ni can be a bcc stabilizer for Fe at high temperatures and inner core pressures. A small amount of Ni can accelerate Fe's crystallization at core pressures. These results suggest that Ni may substantially impact the structure and formation process of the solid inner core.

Nitration of Pyrrolo[2,1-a]isoquinolines.

We have successfully modified a series of pyrrolo[2,1-a]isoquinolines via direct nitration under mild reaction conditions. Easily accessible nitrates including CAN, Cu(NO3)2·H2O, and Fe(NO3)3·9H2O all can serve as effective nitrating reagents for functionalizing pyrrolo[2,1-a]isoquinolines. Various nitro-bearing pyrrolo[2,1-a]isoquinolines have been efficiently prepared in acceptable to good yields.

Recent progress in the oxidative bromination of arenes and heteroarenes.

Oxidative bromination has been serving as a powerful tool for the synthesis of bromo-containing molecules, as this bromination strategy features environmental friendliness, high flexibility in reaction system design and wide abundance of bromide sources and oxidants. The past decade has witnessed a large number of efficient oxidative bromination reaction systems and novel brominated aromatics. This review summarizes recent developments in the field of oxidative preparation of bromoarenes and bromoheteroarenes covering from 2012 to 2022.

Exploring the absolute yield curve of secondary electrons using machine learning methods.

Knowledge of absolute secondary electron yield (δ) is important for various applications of electron emission materials. Besides, it is also crucial to know the dependence of δ on primary electron energy Ep and material properties like atomic number Z. The available experimental database of δ reveals a large discrepancy among the measurement data, while the oversimplified semi-empirical theories of secondary electron emission can only present the general shape of the yield curve but not the absolute yield value. This limits not only the validation of a Monte Carlo model for theoretical simulations but also presents large uncertainties in the applications of different materials for various purposes. In applications, it is highly desirable to have the knowledge of the absolute yield of a material. Therefore, it is highly desirable to establish the relationship of the absolute yield with material and electron energy based on the available experimental data. Recently, machine learning (ML) methods have been increasingly used for the prediction of material properties mainly based on the atomistic calculations with the first-principles theory. We propose here the application of ML models to a material property study, starting with experimental observations and unfolding the relationship of δ with basic material properties and primary electron energy. Our ML models are able to predict δ(Ep)-curve covering a wide energy range of 10 eV-30 keV for unknown elements within the uncertainty range of the experimental data and can suggest more reliable data among the scattered experimental data.

Establishment and validation of an electron inelastic mean free path database for narrow bandgap inorganic compounds with a machine learning approach.

Narrow bandgap inorganic compounds are extremely important in many areas of physics. However, their basic parameter database for surface analysis is incomplete. Electron inelastic mean free paths (IMFPs) are important parameters in surface analysis methods, such as electron spectroscopy and electron microscopy. Our previous research has presented a machine learning (ML) method to describe and predict IMFPs from calculated IMFPs for 41 elemental solids. This paper extends the use of the same machine learning method to 42 inorganic compounds based on the experience in predicting elemental electron IMFPs. The in-depth discussion extends to including material dependence discussion and parameter value selections. After robust validation of the ML method, we have produced an extensive IMFP database for 12 039 narrow bandgap inorganic compounds. Our findings suggest that ML is very efficient and powerful for IMFP description and database completion for various materials and has many advantages, including stability and convenience, over traditional methods.

Mapping stress inside living cells by atomic force microscopy in response to environmental stimuli.

The response of cells to environmental stimuli, under either physiological or pathological conditions, plays a key role in determining cell fate toward either adaptive survival or controlled death. The efficiency of such a feedback mechanism is closely related to the most challenging human diseases, including cancer. Since cellular responses are implemented through physical forces exerted on intracellular components, more detailed knowledge of force distribution through modern imaging techniques is needed to ensure a mechanistic understanding of these forces. In this work, we mapped these intracellular forces at a whole-cell scale and with submicron resolution to correlate intracellular force distribution to the cytoskeletal structures. Furthermore, we visualized dynamic mechanical responses of the cells adapting to environmental modulations in situ. Such task was achieved by using an informatics-assisted atomic force microscope (AFM) indentation technique where a key step was Markov-chain Monte Carlo optimization to search for both the models used to fit indentation force-displacement curves and probe geometry descriptors. We demonstrated force dynamics within cytoskeleton, as well as nucleoskeleton in living cells which were subjected to mechanical state modulation: myosin motor inhibition, micro-compression stimulation and geometrical confinement manipulation. Our results highlight the alteration in the intracellular prestress to attenuate environmental stimuli; to involve in cellular survival against mechanical signal-initiated death during cancer growth and metastasis; and to initiate cell migration.

Modulating oxidative stress counteracts specific antigen-induced regulatory T-cell apoptosis in mice.

Treg are known to have a central role in orchestrating immune responses, but less is known about the destiny of Treg after being activated by specific Ags. This study aimed to investigate the role of superoxide dismutase, an active molecule in the regulation of oxidative stress in the body, in the prevention of Treg apoptosis induced by specific Ags. Ag-specific Tregs were isolated from the DO11.10 mouse intestine. A food allergy mouse model was developed with ovalbumin as the specific Ag and here, we observed that exposure to specific Ag induced Treg apoptosis through converting the precursor of TGF-ß to its mature form inside the Tregs. Oxidative stress was induced in Tregs upon exposure to specific Ags, in which Smad3 bound the latency-associated peptide to induce its degradation, converting the TGF-ß precursor to its mature form, TGF-ß. Suppressing oxidative stress in Tregs alleviated the specific Ag-induced Treg apoptosis in in vitro experiments and suppressed experimental food allergy by preventing the specific Ag-induced Treg apoptosis in the intestine. In conclusion, exposure to specific Ags induces Treg apoptosis and it can be prevented by upregulating superoxide dismutase or suppressing reactive oxidative species in Tregs.

First Report of Black Spot Needle Blight of Pinus sylvestris var. mongolica Litv. Caused by Heterotruncatella spartii in China.

Pinus sylvestris var. mongolica Litv. (Pinales: Pinaceae) is an excellent tree for soil and water conservation in Northeast China. The Honghua'erji area in Inner Mongolia is the "hometown of P. sylvestris var. mongolica", however, in recent years, coniferous diseases of P. sylvestris var. mongolica have frequently occurred here. During the investigation, it was found that some black spot needle blight had been observed in addition to the common blight caused by Sphaeropsis sapinea. From May to September 2020, black spot needle blight was found on hundreds of P. sylvestris var. mongolica trees in four forest farms, and the infection rate among the forests was 24.58 % (n=240). This disease first appeared on the upper part of the needles, and the needles then became withered and gradually showed light black spots, although they remained green. As the disease progressed, the needles eventually died and turned gray with many dark black spots. Fungal isolate named YJ-1 was obtained from infected needles of symptomatic pine trees, and a voucher specimen was deposited in Heilongjiang Province Key Laboratory of Forest Protection. Microscopic observation showed the conidia were 3-septate (4 cells) clavate spindles that measured 23.9 µm (20.8-25.9) × 5.9 µm (4.5-8.2) (n=50). The middle two cells were dark brown, and the septa were darker than the cells. Both apical and basal cells were hyaline. The apical cell had 2-4 appendages (mostly 3), and the basal cell had a truncate base (n=50). The cultural characteristics on potato dextrose agar medium were flat off-white and dense in 3-5 d. At approximately 5-7 d, the reverse side of the colony turned pale to slightly luteous. Superficial black acervuli were distributed in the center of the mature colonies after 10 d. Morphological, cultural and microscopic characteristics observed were similar of Heterotruncatella spartii (basionym: Truncatella spartii) reported by Hlaiem et al (2019). To further identify, total DNA was extracted and the internal transcribed spacer region (ITS-rDNA) was amplified by PCR using the primers ITS1/ITS4 and sequenced for BLASTn analysis and phylogenetic tree construction. The resulting 564 bp sequence (GenBank Accession No. OL662864) had 99.24% (521/525) to H. spartii MFLUCC 15-0537, with bootstrap support of at least 94% using the Neighbor-Joining algorithm by MEGA-X (Felsenstein, 1985). The fungus was identified as H. spartii based on morphology and molecular methods. A pathogenicity test was conducted by preparing a conidial suspension of 2.0 × 107 conidia/mL. The suspension was sprayed onto the needles of 20 pots of annual P. sylvestris ar. mongolica seedlings, and the control was sprayed with sterile water. Then the seedlings were placed in a constant temperature room at 25 °C. After 30 d, typical symptoms appeared on 11 inoculated needles, while the control needles remained symptomless. After 50 d, the re-isolation infection rate reached 66.7 %. The fungus present on the inoculated seedlings was morphologically identical to that originally observed on diseased pines, fulfilling Koch's postulates. The fungus was isolated from Spartium junceum for the first time and designated Truncatella spartii (Senanayake et al, 2015). It was then renamed H. spartii (Liu et al, 2019) and has been reported to infect P. pinea in Tunisia (Hlaiem et al, 2019). To our knowledge, this is the first report of H. spartii causing black spot needle blight on P. sylvestris var. mongolica in China and worldwide.

Mechanomics Biomarker for Cancer Cells Unidentifiable through Morphology and Elastic Modulus.

Cellular mechanical properties are potential cancer biomarkers used for objective cytology to replace the current subjective method relying on cytomorphology. However, heterogeneity among intra/intercellular mechanics and the interplay between cytoskeletal prestress and elastic modulus obscured the difference detectable between malignant and benign cells. In this work, we collected high density nanoscale prestress and elastic modulus data from a single cell by AFM indentation to generate a cellular mechanome. Such high dimensional mechanome data was used to train a malignancy classifier through machine learning. The classifier was tested on 340 single cells of various origins, malignancy, and degrees of similarity in morphology and elastic modulus. The classifier showed instrument-independent robustness and classification accuracy of 89% with an AUC-ROC value of 93%. A signal-to-noise ratio 8 times that of the human-cytologist-based morphological method was also demonstrated, in differentiating precancerous hyperplasia cells from normal cells derived from the same lung cancer patient.

Epithelial cell-derived CD83 restores immune tolerance in the airway mucosa by inducing regulatory T-cell differentiation.

The mechanism of generation of regulatory T cells (Treg) remains incompletely understood. Recent studies show that CD83 has immune regulatory functions. This study aims to investigate the role of epithelial cell-derived CD83 in the restoration of immune tolerance in the airway mucosa by inducing the Treg differentiation. In this study, CD83 and ovalbumin (OVA)-carrying exosomes were generated from airway epithelial cells. An airway allergy mouse model was developed to test the role of CD83/OVA-carrying exosomes in the suppression of airway allergy by inducing Treg generation. We observed that mouse airway epithelial cells expressed CD83 that could be up-regulated by CD40 ligand. The CD83 deficiency in epithelial cells retarded the Treg generation in the airway mucosa. CD83 up-regulated transforming growth factor-ß-inducible early gene 1 expression in CD4+ T cells to promote Foxp3 expression. Exposure of primed CD4+ T cells to CD83/OVA-carrying exosomes promoted antigen-specific Treg generation. Administration of CD83/OVA-carrying exosomes inhibited experimental airway allergic response. In summary, airway epithelial cells express CD83 that is required in the Treg differentiation in the airway mucosa. Administration of CD83/OVA-carrying exosomes can inhibit airway allergy that has the translation potential in the treatment of airway allergic disorders.

Interaction between Ras and Bcl2L12 in B cells suppresses IL-10 expression.

The pathogenesis of recurrent tonsillitis is to be further investigated. B cell-derived interleukin (IL)-10 plays a critical role in immune regulation. Ras activation plays an important role in cancer and many immune disorders. This study aims to investigate the role of Ras activation in down regulating IL-10 expression in tonsillar B cells. Surgically removed tonsil tissues were collected from patients with recurrent acute tonsillar inflammation; B cells were isolated from the tonsillar tissues by flow cytometry sorting to be analyzed by the Ras-specific enzyme-linked immunosorbent assay and pertinent immunological approaches. We found that, compared to peripheral B cells (pBC), B cells isolated from the tonsillar tissues with recurrent inflammation (tBC) showed higher Ras activation, lower IL-10 expression and higher Bcl2L12 expression. Bcl2L12 formed a complex with GAP (GTPase activating protein) to prevent Ras from deactivating. The Ras activation triggered the MAPK/Sp1 pathway to promote the Bcl2L12 expression in B cells. Bcl2L12 prevented the IL-10 expression in tBCs, that was counteracted by inhibition of Ras or the Ras signal transduction pathway. In conclusion, Bcl2L12 interacts with Ras activation to compromise immune tolerance in the tonsils by inhibiting the IL-10 expression in tBCs. Inhibition of Bcl2L12 can restore the IL-10 expression in tBCs.

Twist1 sustains the apoptosis resistance in eosinophils in nasal mucosa of allergic rhinitis.

Eosinophils (Eos) are the canonical effector cells in allergic rhinitis (AR) and many inflammatory diseases. The mechanism of eosinophilia occurring in the lesion sites is not fully understood yet. Twist1 protein (Twist, in short) is an apoptosis inhibitor that also has immune regulatory functions. This study aims to investigate the role of Twist in the pathogenesis of eosinophilia in AR. In this study, surgically removed human nasal mucosal samples were obtained from patients with chronic sinusitis and nasal polyps with AR (the AR group) or without AR (the nAR group). Eos were isolated from the samples by flow cytometry. We found that abundant Eos were obtained from the surgically removed nasal mucosa tissues of both nAR and AR groups. Significantly higher Ras activation was detected in AR Eos than that in nAR Eos. Ras activation was associated with the apoptosis resistance in AR Eos. The Twist (an apoptosis inhibitor) expression was higher in AR Eos, which was positively correlated with the Ras activation status. The sensitization to IgG induced Twist expression in Eos, in which Ras activated the MAPK-HIF-1α pathway, the latter promoted the Twist gene transcription. Twist bound Rac GTPase activating protein-1 to sustain the Ras activation in Eos. Ras activation sustained the apoptosis resistance in Eos. In conclusion, high Ras activation was detected in the AR nasal mucosal tissue-isolated Eos. IgG-sensitization induced Ras activation and Twist expression in Eos, that conferred Eos the apoptosis resistance.

Charging effect induced by electron beam irradiation: a review.

Charging effect frequently occurs when characterizing nonconductive materials using electrons as probes and/or signals and can impede the acquisition of useful information about the material under investigation. It is not adequate to investigate it merely by experiments, but theoretical investigations, for which the Monte Carlo method is a suitable tool, are also necessary. In this paper we review Monte Carlo simulations and selected experiments, intending to provide general insight into the charging effects induced by electron beam irradiation. We will introduce categories of the charging effect, the theoretical framework that is adopted in Monte Carlo modeling of the charging effect and present some typical simulation results. At last, with the knowledge on charging effect imparted by the above contents, we will discuss the measures that can be used for minimizing it.

Specific antigen-guiding exosomes inhibit food allergies by inducing regulatory T cells.

The therapies for food allergy (FA) need to be improved. The generation of inducible regulatory T cells (Tregs) can support immune tolerance in the body. This study aims to suppress experimental FA by inducing Tregs through the employment of modified exosomes (mExosomes). In this study, mExosomes were prepared by incubating dendritic cells with interleukin (IL)-2 and ovalbumin (OVA, used as a specific antigen) in the culture. Exosomes were purified from culture supernatant and used as the mExosomes. A murine FA model was developed to test the effects of mExosomes on the generation of Tregs in the mouse intestinal tissues and inhibiting FA. The results showed that mExosomes, which carried IL-2 and a complex of OVA peptide-major histocompatibility complex class II on the surface of exosomes, bound to OVA-specific CD4+ T cells and induced CD4+ T cells to differentiate into Tregs. In the FA mouse intestinal tissues, we found low IL-2 levels that were positively correlated with the number of Tregs. Depletion of IL-2 in mice prevented the generation of Tregs. The levels of peroxisome proliferator-activated receptor-γ were increased in the FA intestinal tissues with inhibited IL-2 production. Administration of mExosomes induced Tregs in the intestinal tissues and efficiently suppressed FA in mice. We conclude that the mExosomes can suppress FA in mice through inducing Tregs. The data suggest that the mExosomes have translational potential in the treatment of FA and other allergic disorders.

Rational Design of Nanoporous MoS2 /VS2 Heteroarchitecture for Ultrahigh Performance Ammonia Sensors.

2D transition metal dichalcogenides (TMDs) have received widespread interest by virtue of their excellent electrical, optical, and electrochemical characteristics. Recent studies on TMDs have revealed their versatile utilization as electrocatalysts, supercapacitors, battery materials, and sensors, etc. In this study, MoS2 nanosheets are successfully assembled on the porous VS2 (P-VS2 ) scaffold to form a MoS2 /VS2 heterostructure. Their gas-sensing features, such as sensitivity and selectivity, are investigated by using a quartz crystal microbalance (QCM) technique. The QCM results and density functional theory (DFT) calculations reveal the impressive affinity of the MoS2 /VS2 heterostructure sensor toward ammonia with a higher adsorption uptake than the pristine MoS2 or P-VS2 sensor. Furthermore, the adsorption kinetics of the MoS2 /VS2 heterostructure sensor toward ammonia follow the pseudo-first-order kinetics model. The excellent sensing features of the MoS2 /VS2 heterostructure render it attractive for high-performance ammonia sensors in diverse applications.

Structurally diverse sesquiterpenoids from the aerial parts of Artemisia annua (Qinghao) and their striking systemically anti-inflammatory activities.

Thirteen new sesquiterpenoids, arteannoides F-R (1-13), along with 13 known analogues (14-26), were isolated from the dried aerial parts of Artemisia annua L. Their structures, including absolute configurations, were unambiguously determined by a combination of physical data analyses (HRESIMS, 1D and 2D NMR, and ECD) as well as the crystal structures of 1, 5, 6, 15, 19, and 23. Among the isolated compounds, 1 features an unusual 11-oxatricyclo[6.2.1.04,9]undecan-2-ene ring system, 5 possesses an uncommon 4,11-ether bridged tricyclic framework, whereas 6 is a new eudesmane-type sesquiterpenoid formed via rearrangement of its carbon backbone. The systemically anti-inflammatory activities of all isolates were evaluated by measuring their inhibitory effects on PGE2, NO, TNF-α, and IL-6 production in LPS-stimulated RAW 264.7 macrophages. Moreover, the structure activity relationships of some compounds are summarized, this study will provide new structural templates for discovering potential anti-inflammatory agents.

Dilation of the cystic duct confluence in laparoscopic common bile duct exploration and stone extraction in patients with secondary choledocholithiasis.

BACKGROUND: Many options exist for the management of cholelithiasis and secondary choledocholithiasis. Among them, laparoscopic common bile duct exploration (LCBDE) with choledocotomy followed by laparoscopic cholecystectomy has gained popularity. However, efforts should be made to ensure minimally invasive or noninvasive management of the common bile duct (CBD). The purpose of this study was to explore the clinical experience of non-invasive surgical modality, i.e., laparoscopic transcystic dilation of the cystic duct confluence in CBD exploration (LTD-CBDE), including feasibility, safety, adverse events, and incidence. METHODS: In this retrospective analysis, 68 patients were offered the LTD-CBDE technique from December 2015 to April 2018 based on patient's own intention. During the surgery, the cystic duct confluence was dilated with separation forceps and/or a columnar dilation balloon. Subsequently, CBD exploration and stone extraction were performed with a choledochoscope. The entrance of the CBD was covered with a cystic duct stump wall and was subjected to primary closure at the end of surgery. RESULTS: Forty-nine females and 19 males with cholelithiasis and secondary choledocholithiasis were included. The mean age was 53 years old (18 to 72 year). Of these patients, 62 (91.2%) were successfully treated with the LTD-CBDE technique, and bile leakage was observed in 3 patients (4.4%). The mean operation time was 106 min, and the mean hospital stay was 5.9 days. Among the other 6 patients, 3 were converted to open cholecystectomy due to severe fibrosis, unclear anatomical structure at Calot's triangle (n = 2) or Mirizze syndrome (n = 1); LCBDE was performed in 3 patients due to cystic duct atresia (n = 2) and low level of flow from the gallbladder duct into the CBD (n = 1). These patients had a smooth postoperative course. In total, 43/68 of the patients presented no radiological evidence of retained CBD stones at the postoperative follow-up (40 patients treated with LTD-CBDE) 1 year later. CONCLUSIONS: The current work suggests that LTD-CBDE for the management of cholelithiasis and secondary choledocholithiasis is a feasible, safe and effective technique with a low complication rate. LTD-CBDE offers another alternative for surgeons to treat patients in similar scenarios. However, additional randomized, controlled studies are needed to demonstrate its efficacy, safety, and impact on CBD stenosis.

Mal-deficiency impairs the tolerogenicity of dendritic cell of patients with allergic rhinitis.

The tolerogenic dendritic cell dysfunction is associated with the pathogenesis of immune diseases. Microbial stimulus is required in the maintenance of immune functions. This study aims to elucidate the role of Mal signal in the maintenance of DEC205+ DC (decDC) immune tolerogenic function. In this study, peripheral DCs were collected from allergic rhinitis (AR) patients and healthy control (HC) subjects to assess the functional status of decDCs. An AR murine model was developed to test the role of Mal signals in the maintenance of decDCs' functions. We observed that AR decDCs (decDCs obtained from AR patients) were incompetent in the induction of type 1 regulatory T cells (Tr1 cells). AR decDCs expressed less IL-10 than that in HC decDCs. IL-10 mRNA decayed spontaneously in AR decDCs. Tat-activating regulatory DNA-binding protein-43 (TDP43) protected IL-10 mRNA from decay. AR decDCs expressed lower levels of Mal than that in HC decDCs. Mal depletion resulted in IL-10 mRNA decay in HC decDCs. Reconstitution of Mal in AR decDCs restored the capacity of inducing Tr1 cells and attenuated experimental AR in mice. In conclusion, Mal plays a critical role in the maintenance of decDC's immune tolerogenic function. The absence or insufficient Mal signal impairs decDC's tolerogenic property. Reconstitution of Mal in AR decDCs can restore the immune tolerogenic capacity, which may have translational potential in the treatment of AR and other allergic diseases.

New phenylpropanoid allopyranosides from the rhizomes of Cimicifuga dahurica.

Five new phenylpropanoid allopyranosides (1-5), along with five known compounds (6-10) were isolated from the rhizomes of Cimicifuga dahurica. Their structures were established by means of spectroscopic analyses and chemical methods, as well as comparison with literatures. The anti-inflammatory activities of all isolates were evaluated. Compounds 6, 9 and 10 exhibited inhibitory effects on PGE2 production in LPS stimulated RAW 264.7 macrophages with IC50 values of 19.72, 6.33 and 39.90 µM, respectively.

Unveiling the principle descriptor for predicting the electron inelastic mean free path based on a machine learning framework.

The TPP-2M formula is the most popular empirical formula for the estimation of the electron inelastic mean free paths (IMFPs) in solids from several simple material parameters. The TPP-2M formula, however, poorly describes several materials because it relies heavily on the traditional least-squares analysis. Herein, we propose a new framework based on machine learning to overcome the weakness. This framework allows a selection from an enormous number of combined terms (descriptors) to build a new formula that describes the electron IMFPs. The resulting framework not only provides higher average accuracy and stability but also reveals the physics meanings of several newly found descriptors. Using the identified principle descriptors, a complete physics picture of electron IMFPs is obtained, including both single and collective electron behaviors of inelastic scattering. Our findings suggest that machine learning is robust and efficient to predict the IMFP and has great potential in building a regression framework for data-driven problems. Furthermore, this method could be applicable to find empirical formula for given experimental data using a series of parameters given a priori, holds potential to find a deeper connection between experimental data and a priori parameters.