Organocatalytic Enantioselective 1,12-Addition of Alkynyl Biphenyl Quinone Methides Formed In Situ

The chemistry of quinone methides formed in situ has been flourishing in recent years. In sharp contrast, the development and utilization of biphenyl quinone methides are rare. Herein, we achieved a remote stereocontrolled 1,12-conjugate addition of biphenyl quinone methides formed in situ for the first time. In the presence of a suitable chiral phosphoric acid, alkynyl biphenyl quinone methides were generated from α-[4-(4-hydroxyphenyl)phenyl]propargyl alcohols, followed by enantioselective 1,12-conjugate addition with indole-2-carboxylates. The strategy enabled the additional alcohols to serve as efficient allenylation reagents, providing a practical access to a broad range of axially chiral allenes bearing (1,1'-biphenyl)-4-ol unit that are previously less accessible. Combined with control experiments, density functional theory calculations shed light on the reaction mechanism, indicating that enantioselectivity originates from the nucleophilic addition of alkynyl biphenyl quinone methides. Notably, not only the presence of biphenyl quinone methides as versatile intermediates was confirmed but also organocatalytic enantioselective 1,12-addition was established for the first time. This work enriched the family of quinone methides and provided a new platform for the remote stereocontrolled transformation of such versatile intermediates.

Copper-Catalyzed Enantioconvergent Radical N-Alkylation of Diverse (Hetero)aromatic Amines

The 3d transition metal-catalyzed enantioconvergent radical cross-coupling provides a powerful tool for chiral molecule synthesis. In the classic mechanism, the bond formation relies on the interaction between nucleophile-sequestered metal complexes and radicals, limiting the nucleophile scope to sterically uncongested ones. The coupling of sterically congested nucleophiles poses a significant challenge due to difficulties in transmetalation, restricting the reaction generality. Here, we describe a probable outer-sphere nucleophilic attack mechanism that circumvents the challenging transmetalation associated with sterically congested nucleophiles. This strategy enables a general copper-catalyzed enantioconvergent radical N-alkylation of aromatic amines with secondary/tertiary alkyl halides and exhibits catalyst-controlled stereoselectivity. It accommodates diverse aromatic amines, especially bulky secondary and primary ones to deliver value-added chiral amines (>110 examples). It is expected to inspire the coupling of more nucleophiles, particularly challenging sterically congested ones, and accelerate reaction generality.

Controlled and Regioselective Ring-Opening Polymerization for Poly(disulfide)s by Anion-Binding Catalysis

Poly(disulfide)s are an emerging class of sulfur-containing polymers with applications in medicine, energy, and functional materials. However, the constituent dynamic covalent S-S bond is highly reactive in the presence of the sulfide (RS-) anion, imposing a persistent challenge to control the polymerization. Here, we report an anion-binding approach to arrest the high reactivity of the RS- chain end to control the synthesis of linear poly(disulfide)s, realizing a rapid, living ring-opening polymerization of 1,2-dithiolanes with narrow dispersity and high regioselectivity (Mw/Mn ∼ 1.1, Ps ∼ 0.85). Mechanistic studies support the formation of a thiourea-base-sulfide ternary complex as the catalytically active species during the chain propagation. Theoretical analyses reveal a synergistic catalytic model where the catalyst preorganizes the protonated base and anionic chain end to establish spatial confinement over the bound monomer, effecting the observed regioselectivity. The catalytic system is amenable to monomers with various functional groups, and semicrystalline polymers are also obtained from lipoic acid derivatives by enhancing the regioselectivity.

An alternating continuous integration system for magnetic measurements for experimental advanced superconducting tokamak

Integrators are critical instruments used for magnetic measurement systems (MMSs) in tokamaks, and, currently, the Experimental Advanced Superconducting Tokamak (EAST) has over 600 deployed. However, these integrators, designed with real-time drift compensation, will not be able to support longer pulse operations in the near future due to saturation and drift. To address these issues, this paper proposes a new alternating integration system combining analog integration with drift digital rectification. This system utilizes a microcontroller unit (MCU) to control two parallel analog integrators to work alternatively, compensate their drifts based on their respective error characteristics, and assemble the two integration segments together. The designed architecture provides highly flexible capabilities in operation modes and error correction, which make the system operation and maintenance highly automated. Performance tests on the EAST experiment site show that the prototype integrator can meet the requirements of real-time plasma control for a duration of hour-level.

Organocatalytic Enantioselective 1,8-Addition for the Synthesis of Chiral Tetraarylmethanes from 2-Naphthol/Naphthalen-2-amine-Based Tertiary Alcohols

Catalytic enantioselective construction of optically active tetraarylmethanes remains a challenging issue in the field of asymmetric synthesis because of the overwhelming steric hindrance and formidable stereocontrol that existed in construction of the all-aryl-substituted quaternary carbon stereocenter. Here, we reported an organocatalytic asymmetric synthesis of chiral tetraarylmethanes from racemic tertiary alcohols. With the aid of a chiral phosphoric acid catalyst, 6-methylenenaphthalen-2(6H)-ones were generated in situ from 6-(hydroxydiarylmethyl)naphthalen-2-ols, followed by stereoselective 1,8-conjugate addition to afford the corresponding tetraarylmethanes in high to excellent yields with high enantioselectivities. Furthermore, the scope of tertiary alcohols has been successfully enlarged to 6-(hydroxydiphenylmethyl)naphthalen-2-amines. Notably, it is the first time to use 2-naphthol/naphthalen-2-amine unit as the auxiliary group to in situ generate α,β,γ,δ,ε,ζ-conjugate systems, which have been successfully involved in organocatalytic remote stereocontrolled 1,8-conjugate addition reactions. Particularly, organocatalytic stereoconvergent formal nucleophilic substitution reaction of triarylmethanols has been achieved for the asymmetric construction of chiral tetraarylmethanes. In addition, DFT calculations have been applied to provide guidance for the design of additional tertiary alcohols and understand the origin of stereoselectivity.

[Effects of angiotensin-converting enzyme on reproduction of Culex pipiens pallens]

OBJECTIVE

To investigate the role of angiotensin-converting enzyme (ACE) in the reproduction of Culex pipiens pallens, so as to provide insights into selection of targets for controlling mosquito vector populations.

METHODS

Cx. pipiens pallens was collected from Tangkou County, Shandong Province in 2009. Female and male mosquitoes were selected at 72 hours post-eclosion, and quantitative real-time reverse transcription PCR (qPCR) assay was used to detect the expression of ACE gene in the whole body and reproductive tissues of male mosquitoes and fertilized female mosquitoes before (0 h) and after blood meals (24, 48, 72 h), respectively. Then, 150 female and 150 male mosquitoes at 0 to 4 hours post-eclosion were selected and divided into the wild-type group (WT group), small interfering RNA-negative control group (siNC group) and small interfering RNA-ACE group (siACE group), of 50 mosquitoes in each group. Mosquitoes in the WT group were given no treatment, and mosquitoes in the siNC and siACE groups were given microinjection of siNC and siACE into the hemolymph at a dose of 0.3 μg per mosquito. The knockdown efficiency was checked using qPCR assay, and the reproductive phenotype of mosquitoes was observed.

RESULTS

The relative ACE gene expression was higher in the whole body of male mosquitoes (5.467 ± 1.006) relative to females (1.199 ± 0.241) (t = 5.835, P = 0.004) at 72 h post-eclosion, and the highest ACE expression was seen in reproductive tissues of male mosquitoes (199.100 ± 24.429), which was 188.3 times higher than in remaining tissues (1.057 ± 0.340) (t = 6.602, P = 0.002). Blood meal induced high ACE expression in all body tissues of fertilized female mosquitoes, with peak expression at 24 h after blood meals (14.957 ± 2.815), which was 14.8 times higher than that before blood meals (1.009 ± 0.139) (P = 0.002). The transcriptional level of ACEs continued to increase in the ovaries of female mosquitoes after blood meals during the vitellogenesis phase, peaking at 48 h after blood meals (5.500 ± 0.734), which was 5.1 times higher than that before blood meals (1.072 ± 0.178) (P = 0.002). Small RNA interference targeting ACE resulted in a 57.2% reduction in ACE expression in female mosquitoes in the siACE group (0.430 ± 0.070) relative to the siNC group (1.002 ± 0.070) (P = 0.001), and a 41.1% reduction in male mosquitoes in the siACE group (0.588 ± 0.067) relative to the siNC group (1.008 ± 0.131) (P = 0.016). Knockdown of ACE expression resulted in a 48.0% decrease in the number of eggs laid by female mosquitoes in the siACE group [(94.000 ± 27.386) eggs] relative to the siNC group [(180.800 ± 27.386)] (P < 0.001), and a 45.0% decrease in the number of eggs laid by wild female mosquitoes mated with males in the siACE group [(104.500 ± 20.965) eggs] relative to the siNC group [(190.050 ± 10.698) eggs] (P < 0.001).

CONCLUSIONS

Reduced ACE expression may inhibit the fecundity of male and female mosquitoes, and ACE may be as a potential target for mosquito vector population suppression.

The very large n2EDM magnetically shielded room with an exceptional performance for fundamental physics measurements

We present the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute, which features an interior cubic volume with each side of length 2.92 m, thus providing an accessible space of 25 m³. The MSR has 87 openings of diameter up to 220 mm for operating the experimental apparatus inside and an intermediate space between the layers for housing sensitive signal processing electronics. The characterization measurements show a remanent magnetic field in the central 1 m³ below 100 pT and a field below 600 pT in the entire inner volume, up to 4 cm to the walls. The quasi-static shielding factor at 0.01 Hz measured with a sinusoidal 2 μT peak-to-peak signal is about 100 000 in all three spatial directions and increases rapidly with frequency to reach 10⁸ above 1 Hz.

Organocatalytic Enantioselective 1,10-Addition of Alkynyl Indole Imine Methides with Thiazolones: An Access to Axially Chiral Tetrasubstituted Allenes

An asymmetric organocatalytic remote 1,10-addition of alkynyl indole imine methides generated in situ from α-(6-indolyl) propargylic alcohols with thiazolones has been developed for the first time, affording axially chiral tetrasubstituted allenes featuring vicinal sulfur-containing quaternary carbon stereocenters in high yields with excellent stereoselectivities. The representative scale-up reaction and transformations of the 1,10-adduct were examined. The reaction mechanism was expounded by control experiments and DFT calculations.

The inhibitory effect of LINC00261 upregulation on the pancreatic cancer EMT process is mediated by KLF13 via the mTOR signaling pathway

PURPOSE

The long noncoding RNA LINC00261 was reported to be involved in carcinogenesis and has been validated as a tumor suppressor in pancreatic cancer (PC); however, how LINC00261 is regulated has not been fully examined. Here, we attempted to investigate the upstream and downstream targets of LINC00261 in PC.

METHODS

LINC00261 expression in PC tissues was examined by the Gene Expression Omnibus (GEO) datasets and the Gene Expression Profiling Interactive Analysis (GEPIA) database. The quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays were performed to detect the expression level of LINC00261 in PC cells. The location of LINC00261 in PC cells was identified by RNA fluorescence in situ hybridization (RNA-FISH). Cell Counting Kit-8 (CCK-8), cell apoptosis assay, transwell invasion and migration assays testified the critical role of LINC00261 in PC. The luciferase reporter assay was applied to confirm the binding of LINC00261 to its upstream transcription factor KLF13. The changes in LINC00261 related target protein levels were analyzed by Western blotting assay.

RESULTS

LINC00261 was significantly lower in PC tissues and was mainly concentrated in the nucleus. Overexpression of LINC00261 inhibited the invasion and migration of PC cells. Mechanistically, transcription factor KLF13 was confirmed to inhibit the epithelial-mesenchymal transition (EMT) process of PC cells by promoting the transcription of LINC00261 and suppressing the expression of metastasis-associated proteins, such as matrix metalloproteinase MMP2 and vimentin, thus inhibiting the metastasis of PC.

CONCLUSION

LINC00261 regulates PC cell metastasis through the "KLF13-LINC00261-mTOR-P70S6K1-S6" signaling pathway, which provides a significant set of potential PC therapeutic targets.

Radiographic indexes in AP hip radiographs prior to total hip arthroplasty reveal candidates with low BMD

Using anteroposterior (AP) hip radiograph, we measured several indexes to investigate the association with bone mineral density (BMD) before THA and found a highly effective index to predict femoral BMD. This technique is helpful for both patients and clinicians to identify potential candidates with low BMD to whom DXA examination is particularly recommended.

INTRODUCTION

The purpose of the study is to identify patients with low bone mineral density (BMD) prior to total hip arthroplasty with the help of AP hip radiographs.

METHODS

Indexes on AP hip radiographs and T-scores from DXA examination of the lumbar spine and the affected hip were acquired from patients before THA. Indexes measured on AP hip radiographs including the canal calcar ratio (CCR), canal flare index (CFI), morphological cortical index (MCI), canal bone ratio (CBR), and canal bone area ratio (CBAR). The relevance between indexes and the T-score of femora was evaluated by correlation analysis, and the diagnostic value of indexes for osteopenia was examined by receiver operating characteristic (ROC) curves.

RESULTS

A total of 81 patients were included. The average value of CBR-7, CBR-10, and CBAR (7-10) were highly related to the T-score of femora (r =  - 0.592, r =  - 0.634, and r =  - 0.631, respectively, p < 0.0001). Results of the intra- and interobserver variation assessment was excellent. CBR-7, CBR-10, and CBAR (7-10) were significantly different between the non-osteopenia and osteopenia groups (p < 0.0001). CBR-10 had the biggest area under curve (AUC), means the great diagnostic value for osteopenia in the proximal femora (AUC = 0.821, cutoff value = 0.3805).

CONCLUSION

The canal bone ratio at 10 × 10^-2 m under the level of the lesser trochanter proved to be a great indicator of femoral osteopenia. Trial registration Chinese Clinical Trail Registry, ChiCTR2000041016. Registered 16 December 2020-Retrospectively registered, http://www.chictr.org.cn/listbycreater.aspx .

Asymmetric synthesis of N-bridged [3.3.1] ring systems by phosphonium salt/Lewis acid relay catalysis

Optically pure pseudo-natural products (PNPs), particularly exemplified by azabicyclo[3.3.1]nonane molecules and their analogs provide an attractive platform for structure-activity relationship studies, and also lead new compound discovery in drug development. However, there are currently no examples of guiding catalytic asymmetric strategies available to construct such important PN-scaffolds, thus limiting their broad use. Here, we report a general and modular method for constructing these pseudo-natural N-bridged [3.3.1] ring systems via cascade process by bifunctional phosphonium salt/Lewis acid relay catalysis. A wide variety of substrates bearing an assortment of functional groups (59 examples) are compatible with this protocol. Other features include a [3 + 2] cyclization/ring-opening/Friedel-Crafts cascade pathway, excellent reactivities and stereoselectivities, easily available starting materials, step economy and scalability. The obtained enantioenriched products showed potential of preliminary anticancer activities. Insights gained from our studies are expected to advance general efforts towards the catalytic synthesis of challenging even unprecedented chiral PNPs, offering new opportunities for bioactive small-molecule discovery.

Photocurrent-driven transient symmetry breaking in the Weyl semimetal TaAs

Symmetry plays a central role in conventional and topological phases of matter, making the ability to optically drive symmetry changes a critical step in developing future technologies that rely on such control. Topological materials, like topological semimetals, are particularly sensitive to a breaking or restoring of time-reversal and crystalline symmetries, which affect both bulk and surface electronic states. While previous studies have focused on controlling symmetry via coupling to the crystal lattice, we demonstrate here an all-electronic mechanism based on photocurrent generation. Using second harmonic generation spectroscopy as a sensitive probe of symmetry changes, we observe an ultrafast breaking of time-reversal and spatial symmetries following femtosecond optical excitation in the prototypical type-I Weyl semimetal TaAs. Our results show that optically driven photocurrents can be tailored to explicitly break electronic symmetry in a generic fashion, opening up the possibility of driving phase transitions between symmetry-protected states on ultrafast timescales.

Mechanism and origin of regioselectivity in Rh-catalyzed desymmetric [2 + 2 + 2] cycloaddition: charge versus π–π stacking interaction

Competition between different types of electronic effects (charge versus π–π stacking) controls the regioselectivity of Rh-catalyzed [2 + 2 + 2] cycloaddition.

Rational Design and Organocatalytic Enantioselective [1+4]-Annulations of MBH Carbonates with Modified Enones

According to the frontier molecular orbital theory, two types of modified enones have been designed and successfully applied in the chiral phosphine-catalyzed stereoselective [1+4]-annulation of Morita-Baylis-Hillman (MBH) carbonates for the...

Insight into Regioselective Control in Aerobic Oxidative C-H/C-H Coupling for C3-Arylation of Benzothiophenes: Toward Structurally Nontraditional OLED Materials

The installation of (benzo)thiophene-containing biaryls via coupling reactions has become a staple in designing photoelectric materials. Undeniably, C-H/C-H cross-coupling reactions between two (hetero)aromatics would be a shortcut toward these structural fragments. While more reliable cross-coupling technologies are well-established to provide C2-arylated (benzo)thiophenes, efficient methods that arylate the C3-position remain underdeveloped. Herein we provide insight into the factors that determine regioselectivity switching for these cross-coupling reactions. X-ray crystallographic analysis gives solid evidence for the key roles of triflate in regioselective dearomatization and acetate in base-assisted anti-β-deprotonated rearomatization. The first isolation and X-ray characterization of a medium-sized dearomatized cyclometalated adduct involving both substrates provide extra insight into aerobic oxidative Ar-H/Ar-H cross-coupling reactions. The mechanistic breakthrough incubates the first example, enabling C-H/C-H-type C3-arylation of benzothiophenes. Finally, this chemistry is used to design blue-emitting thermally activated delayed fluorescence (TADF) materials with a helicene conformation that exhibit a high maximum external quantum efficiency of 25.4% in OLED.

Thiamine ameliorates metabolic disorders induced by a long-term high-concentrate diet and promotes rumen epithelial development in goats

Data indicate that dietary thiamine supplementation can partly alleviate rumen epithelium inflammation and barrier function in goats fed a high-concentrate diet. The current work aimed to explore whether thiamine promotes rumen epithelium development by regulating carbohydrate metabolism during a long period of feeding high levels of concentrate. For the experiment, 24 female Boer goats (35.62 ± 2.4 kg of body weight) in parity 1 or 2 were allocated to 3 groups (8 goats per replicate) receiving a low-concentrate diet (concentrate:forage 30:70), a high-concentrate diet (HC; concentrate:forage 70:30), or a high-concentrate diet (concentrate:forage 70:30) supplemented with 200 mg of thiamine/kg of dry matter intake (HCT; concentrate:forage 70:30). On the last day of 12 wk, rumen fluid and blood samples were collected to measure ruminal parameters, endotoxin lipopolysaccharide, and blood inflammatory cytokines. Goats were slaughtered to collect ruminal tissue to determine differential metabolites, enzyme activities, and gene expression. Liquid chromatography-tandem mass spectrometry analysis revealed that the HCT group had significantly increased concentrations of d-glucose 6-phosphate, d-fructose 6-phosphate, glyceraldehyde 3-phosphate, thiamine pyrophosphate, oxaloacetate, acetyl-CoA, succinyl-CoA, sedoheptulose 7-phosphate, ribose 5-phosphate, and NADPH compared with the HC group. The pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and transketolase enzyme activities in the rumen epithelium of the HCT group were higher than those in the HC group. The plasma total antioxidant capacity values for the HCT group were greater than those for the HC group. The rumen epithelium ATP content in the HCT group was higher than that in the HC group. Compared with the HCT group, the HC group had a lower mRNA abundance of CCND1, CCNA2, CDK2, CDK4, CDK6, BCL2, PI3K, and AKT1. Taken together, the results suggest that dietary thiamine supplementation could ameliorate disorders in the tricarboxylic acid cycle and the pentose phosphate pathway induced by a long-term high-concentrate diet and could promote rumen epithelial growth.

The design of the n2EDM experiment: nEDM Collaboration

We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver an order of magnitude better sensitivity with provision for further substantial improvements. An overview is of the experimental method and setup is given, the sensitivity requirements for the apparatus are derived, and its technical design is described.

Initial chest radiograph scores inform COVID-19 status, intensive care unit admission and need for mechanical ventilation

AIM

To evaluate whether portable chest radiography (CXR) scores are associated with coronavirus disease 2019 (COVID-19) status and various clinical outcomes.

MATERIALS AND METHODS

This retrospective study included 500 initial CXR from COVID-19-suspected patients. Each CXR was scored based on geographic extent and degree of opacity as indicators of disease severity. COVID-19 status and clinical outcomes including intensive care unit (ICU) admission, mechanical ventilation, mortality, length of hospitalisation, and duration on ventilator were collected. Multivariable logistic regression analysis was performed to evaluate the relationship between CXR scores and COVID-19 status, CXR scores and clinical outcomes, adjusted for code status, age, gender and co-morbidities.

RESULTS

The interclass correlation coefficients amongst raters were 0.94 and 0.90 for the extent score and opacity score, respectively. CXR scores were significantly (p < 0.01) associated with COVID-19 positivity (odd ratio [OR] = 1.49; 95% confidence interval [CI]: 1.27 - 1.75 for extent score and OR = 1.75; 95% CI: 1.42 - 2.15 for opacity score), ICU admission (OR = 1.19; 95% CI: 1.09 - 1.31 for extent score and OR = 1.26; 95% CI: 1.10 - 1.44 for opacity score), and invasive mechanical ventilation (OR = 1.22; 95% CI: 1.11 - 1.35 for geographic score and OR = 1.21; 95% CI: 1.05 - 1.38 for opacity score). CXR scores were not significantly different between survivors and non-survivors after adjusting for code status (p>0.05). CXR scores were not associated with length of hospitalisation or duration on ventilation (p>0.05).

CONCLUSIONS

Initial CXR scores have prognostic value and are associated with COVID-19 positivity, ICU admission, and mechanical ventilation.

Towards computer-aided severity assessment via deep neural networks for geographic and opacity extent scoring of SARS-CoV-2 chest X-rays

A critical step in effective care and treatment planning for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause for the coronavirus disease 2019 (COVID-19) pandemic, is the assessment of the severity of disease progression. Chest x-rays (CXRs) are often used to assess SARS-CoV-2 severity, with two important assessment metrics being extent of lung involvement and degree of opacity. In this proof-of-concept study, we assess the feasibility of computer-aided scoring of CXRs of SARS-CoV-2 lung disease severity using a deep learning system. Data consisted of 396 CXRs from SARS-CoV-2 positive patient cases. Geographic extent and opacity extent were scored by two board-certified expert chest radiologists (with 20+ years of experience) and a 2nd-year radiology resident. The deep neural networks used in this study, which we name COVID-Net S, are based on a COVID-Net network architecture. 100 versions of the network were independently learned (50 to perform geographic extent scoring and 50 to perform opacity extent scoring) using random subsets of CXRs from the study, and we evaluated the networks using stratified Monte Carlo cross-validation experiments. The COVID-Net S deep neural networks yielded R[Formula: see text] of [Formula: see text] and [Formula: see text] between predicted scores and radiologist scores for geographic extent and opacity extent, respectively, in stratified Monte Carlo cross-validation experiments. The best performing COVID-Net S networks achieved R[Formula: see text] of 0.739 and 0.741 between predicted scores and radiologist scores for geographic extent and opacity extent, respectively. The results are promising and suggest that the use of deep neural networks on CXRs could be an effective tool for computer-aided assessment of SARS-CoV-2 lung disease severity, although additional studies are needed before adoption for routine clinical use.

MiR-593-5p inhibited proliferation and migration of lung adenocarcinoma by targeting ICAM-1

OBJECTIVE

The aim of this study was to investigate the role of microRNA-593-5p (miR-593-5p) in the development of lung adenocarcinoma (LA).

PATIENTS AND METHODS

The expression level of miR-593-5p in LA tissues and cell lines was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Luciferase reporter gene assay and Western blot were performed to evaluate the interaction between miR-593-5p and intercellular cell adhesion molecule-1 (ICAM-1). Furthermore, the effects of the miR-593-5p/ICAM-1 axis on A549 cells were determined by MTS, colony formation assay, and transwell assay, respectively.

RESULTS

MiR-593-5p was significantly downregulated in both clinical samples and cell lines. The bioinformatics analysis predicted that miR-593-5p could complementarily bind to the 3'-UTR of ICAM-1. Luciferase reporter gene assay confirmed that ICAM-1 was the direct target of miR-593-5p. Western blot results demonstrated that miR-593-5p could effectively reduce the protein expression of ICAM-1 in cells. In vitro experiments indicated that the proliferation and migration of A549 cells were significantly inhibited by miR-593-5p transfection. However, the overexpression of ICAM-1 could effectively reverse the inhibitory effects of miR-593-5p in vitro. These results indicated that the inhibitory effects of miR-593-5p on LA were achieved by regulating ICAM-1 expression.

CONCLUSIONS

MiR-593-5p/ICAM-1 axis might be a potential therapeutic target for the diagnosis and treatment of LA.

Improved light extraction efficiency of AlGaN deep-ultraviolet light emitting diodes combining Ag-nanodots/Al reflective electrode with highly transparent p-type layer

Enhancement of light extraction efficiency (LEE) of AlGaN-based deep-ultraviolet (DUV) light emitting diodes (LEDs) has been attempted by adopting Ag-nanodots/Al reflective electrodes on a highly transparent complex p-type layer. By thinning the p-GaN to several nm, highly DUV transparent p-type layer is achieved, making it meaningful for the application of reflective electrodes composed of Ag-nanodots and Al film to allow most light emitted upward to be reflected back to the sapphire side. By this approach, the maximum light output power and external quantum efficiency of the DUV-LEDs with optimized Ag nanodots/Al electrodes are severally increased by 52% and 58%, respectively, compared to those with traditional Ni/Au electrodes when the current is below 200 mA.

Resveratrol protects myocardial apoptosis induced by ischemia-reperfusion in rats with acute myocardial infarction via blocking P13K/Akt/e-NOS pathway

OBJECTIVE

To elucidate the protective role of resveratrol (RSV) in myocardial apoptosis induced by ischemia-reperfusion injury in rats with acute myocardial infarction (AMI), and to explore its underlying mechanism.

MATERIALS AND METHODS

The AMI rat model was successfully established by ligation of the left anterior descending coronary artery. Rat cardiomyocytes were isolated and cultured. Cells were divided into four groups, including: control group (no specific treatment), AMI group (acute ischemia-reperfusion treatment), AMI+RSV group (RSV pretreatment for 24 h before acute ischemia-reperfusion) and AMI+ RSV+LY group (RSV pretreatment combined with 40 μmol/L phosphatidylinositide 3-kinases (PI3K) pathway inhibitor LY294002 for 24 h before acute ischemia-reperfusion). Morphology of apoptotic cardiomyocytes in each group was observed by Hoechst staining. The proliferation, apoptosis and cell cycle progression of cardiomyocytes were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, terminal dexynucleotidyl transferase(TdT)-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry, respectively. Finally, the protein levels of genes relative to PI3K/Akt/eNOS pathway were detected by Western blot.

RESULTS

Hoechst staining showed a large number of necrotic cells, cell retraction, enhanced refractive index and enlarged cell gap in AMI group. A small number of necrotic cells were found in AMI+RSV group, which was significantly fewer than that of AMI group. Meanwhile, remaining cells presented normal morphology. However, a great number of necrotic cells were observed in AMI+RSV+LY group, which was obviously more than that of AMI+RSV group. Compared with control group, cells in AMI group showed significantly decreased proliferative rate, increased early phase, late phase and total one of apoptosis. In AMI group, the ratio of G0/G1 phase was remarkably increased, whereas those of S and G2/M phases were decreased. Moreover, the expression levels of phosphorylated Akt (p-Akt) and phosphorylated e-NOS (p-eNOS) were significantly downregulated in AMI group. In AMI+RSV group, cell apoptosis, cell cycle progression and levels of p-Akt and p-eNOS showed the opposite trends as those of AMI group. However, LY294002 pretreatment reversed the protective role of RSV in cellular behaviors of cardiomyocytes.

CONCLUSIONS

RSV protects cardiomyocyte apoptosis from ischemia-reperfusion injury through regulating phosphorylation levels of proteins relative to PI3K/Akt/e-NOS pathway.

Genotyping and characterization of Toxoplasma gondii strain isolated from pigs in Hubei province, central China

Toxoplasma gondii, a ubiquitous pathogen that infects nearly all warm-blooded animals and humans, can cause severe complications to the infected people and animals as well as serious economic losses and social problems. Here, one local strain (TgPIG-WH1) was isolated from an aborted pig fetus, and the genotype of this strain was identified as ToxoDB #3 by the PCR RFLP typing method using 10 molecular markers (SAG1, SAG2, alternative SAG2, SAG3, BTUB, GRA6, L358, PK1, C22-8, C29-2 and Apico). A comparison of the virulence of this isolate with other strains in both mice and piglets showed that TgPIG-WH1 was less virulent than type 1 strain RH and type 2 strain ME49 in mice, and caused similar symptoms to those of ME49 such as fever in piglets. Additionally, in piglet infection with both strains, the TgPIG-WH1 caused a higher IgG response and more severe pathological damages than ME49. Furthermore, TgPIG-WH1 caused one death in the 5 infected piglets, whereas ME49 did not, suggesting the higher virulence of TgPIG-WH1 than ME49 during piglet infection. Experimental infections indicate that the virulence of TgPIG-WH1 relative to ME49 is weaker in mice, but higher in pigs. This is probably the first report regarding a ToxoDB #3 strain from pigs in Hubei, China. These data will facilitate the understanding of genetic diversity of Toxoplasma strains in China as well as the prevention and control of porcine toxoplasmosis in the local region.

Greatly enhanced performance of AlGaN-based deep ultraviolet light emitting diodes by introducing a polarization modulated electron blocking layer

Carrier transport in AlGaN-based deep ultraviolet (DUV) light emitting diodes (LEDs) with the wavelength of 273 nm has been investigated by introducing polarization modulated electron blocking layer (EBL) that adopts an Al composition and thickness graded multiple quantum barriers (MQB) structure. The experimental result shows that the maximum light output power and external quantum efficiency for the proposed structure at the current of 250 mA are 9.6 mW and 1.03% respectively, severally increasing by 405% and 249% compared to traditional one, meanwhile, the efficiency droop at 250 mA is also dramatically reduced from 42.2% to 16.6%. Further simulation analysis indicates that this graded MQB-EBL enhances the potential barrier height for electrons and meanwhile reduces that for holes, hence effectively suppresses the electron leakage, and at the same time significantly improves the hole injection efficiency. As a result, the whole performance of the LED with the proposed MQB-EBL is dramatically improved.

The relationship of platelet to lymphocyte ratio and neutrophil to monocyte ratio to radiographic grades of knee osteoarthritis

OBJECTIVE

Accumulating data show that platelet to lymphocyte ratio (PLR) and neutrophil to monocyte ratio (NMR) undergo changes during inflammation in various diseases; however, the clinical features remain unclear in knee osteoarthritis (OA) patients. The purpose of our study was to evaluate PLR and NMR in knee OA patients, and assess their relationship to knee OA's radiographic grades.

METHODS

A retrospective study on 132 adult knee OA patients and 162 healthy controls (HC) was performed. All clinical characteristics of the knee OA patients were obtained from their medical records. PLR and NMR were compared between knee OA patients and HC by non-parametric tests. Correlations of PLR and NMR with Kellgren-Lawrence (KL) classification (KL grade 2, KL grade 3, and KL grade 4) were also analyzed through a Spearman correlation test. Ordinal polytomous logistic regression was used to determine independent factors influencing radiographic grades of knee OA patients.

RESULTS

PLR was increased significantly in knee OA patients, while a statistical difference in NMR was not observed. However, PLR was not relevant to KL grades, while NMR was negatively correlated with these (r = -0.330, P < 0.01) and was independently associated with KL grades of knee OA.

CONCLUSION

PLR could reflect the inflammation response of knee OA. NMR emerged as an independent factor and could be used as a potential marker indicating the severity of knee OA.

Difference in the frequency of pouchitis between ulcerative colitis and familial adenomatous polyposis: is the explanation in peripouch fat?

AIM

Patients with ulcerative colitis (UC) have an unexplained higher incidence of pouchitis and a greater amount of peripouch fat compared with patients with familial adenomatous polyposis (FAP). The aims of this study were to compare the peripouch fat areas between patients with UC and patients with FAP, and to explore relationship between peripouch fat and pouchitis or chronic antibiotic-refractory pouchitis (CARP).

METHOD

Patients with an abdominal CT image from our prospectively maintained Pouch Database were included. Abdominal fat and peripouch fat were measured on CT images at different levels or planes. Comparisons of peripouch fat and CARP were performed before and after propensity score matching.

RESULTS

A total of 277 patients with UC and 40 patients with FAP were included. Compared with patients with FAP, patients with UC were found to have a higher incidence of pouchitis (58.5% vs 15.0%, P < 0.001) and CARP (24.5% vs 2.5%, P = 0.002) and a higher total peripouch fat area (P = 0.030) and mesenteric peripouch fat area (P = 0.022) at Level-3. Univariate and multivariate analyses showed that diagnosis (UC vs FAP) and peripouch fat areas at Level-3 and Level-5 were independent risk factors for CARP. With propensity score matching, 38 pairs of patients with UC and FAP were matched successfully. After matching, patients with UC were found to have higher total peripouch fat area and higher mesenteric peripouch fat area at Level-3, and a higher incidence of pouchitis (57.9% vs 13.2%, P < 0.001) and CARP (23.7% vs 2.6%, P = 0.007).

CONCLUSION

Our study demonstrates that patients with UC have more peripouch fat than those with FAP, which may explain the difference in the frequency of pouchitis and CARP between these groups of patients.

[Diagnostic value of serum alpha-fetoprotein, alpha-fetoprotein variant and abnormal prothrombin in primary hepatocellular carcinoma]

Objective: To explore the diagnostic value of single or combined detection of serum tumor markers alpha-fetoprotein (AFP), α-fetoprotein (AFP)-L3 and abnormal clotting (PIVKA-II) in the primary hepatic carcinoma. Methods: Serum AFP, AFP-L3 and PIVKA-II of 56 cases with primary hepatic carcinoma, 46 cases with cirrhosis, 45 cases with other liver disease and 41 healthy persons (control group) were examined by chemiluminescence method, and the differences in the levels of AFP, AFP-L3 and PIVKA-II in each group were compared. Results: Serum level of AFP, AFP-L3 and PIVKA-II in patients with primary liver cancer was significantly higher than that of the cirrhosis, other liver disease and control groups, and the difference was statistically significant (P < 0.05). The receiver operating characteristic curve analysis showed that the areas under the curve for the diagnosis of primary hepatic carcinoma by AFP, AFP-L3 and PIVKA-II were 0.887, 0.846 and 0.885, respectively. The combined use of the three tumor markers for the diagnosis of primary hepatic carcinoma increased the area under the curve to 0.899. Among the single detection, AFP had the highest sensitivity of 91.07% and PIVKA-II had the highest specificity at 88.63%. In the combined detection, AFP/PIVKA-II combination had the highest sensitivity of 94.64 %, while the AFP + AFP-L3 + PIVKA-II combination had the highest specificity at 98.48%. Conclusion: Combined detection of AFP, AFP-L3 and PIVKA-II could improve the diagnostic specificity and the sensitivity of primary hepatic carcinoma; thereby make up the deficiency of single detection and improve the early diagnosis rate.

Operating behavior of micro-LEDs on a GaN substrate at ultrahigh injection current densities

Near-ultraviolet micro-LEDs with different diameters were fabricated on GaN substrates. The electroluminescence and the light output power-current density and current density-voltage relationships were measured. A saturated current density of 358 kA/cm² was achieved with a 20 µm LED. The ideality factor curves showed steps and peaks when the injection current density was increased from 20 to 150 kA/cm² and an abnormal efficiency increase. The transport and recombination processes of micro-LEDs at high injection current densities were simulated, and the many-body effect and phase space filling in the integrated quantum drift-diffusion model were considered. Serious current crowding was observed above 100 kA/cm², even for the 20 µm LED.

A cluster of CYP6 gene family associated with the major quantitative trait locus is responsible for the pyrethroid resistance in Culex pipiens pallen

The emergence and rapid spread of insecticide resistance in several mosquito species has become a significant obstacle in management of mosquito-borne diseases, including deltamethrin resistance in Culex pipiens pallens. Previous study identified a major deltamethrin resistance quantitative trait locus (DR-6) that alone explained 62% of the genetic variance. In this study, the marker L4B1.102 and L4B1.175 associated with the DR-6 were characterized. We searched for potential candidate genes in the flank region of two markers in the genome sequence and showed that a cluster of CYP6 cytochrome P450 genes (CYP6BB4, CYP6BB3, CYP6CC2, CYP6P14, CYP6BZ2, CYP6AA9, CYP6AA8, CYP6AA7) was in the vicinity of DR-6. Significant differences in the expression of these P450s in the larval and adult stages were identified in the resistant strains compared with the susceptible strain. For CYP6AA9 and CYP6BB4, the correlation analysis showed a highly positive correlation between relative gene expression quantification and the resistance level in different strains. Knockdown of CYP6BB4 increased the sensitivity of mosquitoes to deltamethrin. We identified that the deltamethrin resistance was in a cluster of CYP6 genes in C. pipiens pallens, and CYP6BB4 may play a significant role in the development of deltamethrin resistance.

Tracking Ultrafast Photocurrents in the Weyl Semimetal TaAs Using THz Emission Spectroscopy

We investigate polarization-dependent ultrafast photocurrents in the Weyl semimetal TaAs using terahertz (THz) emission spectroscopy. Our results reveal that highly directional, transient photocurrents are generated along the noncentrosymmetric c axis regardless of incident light polarization, while helicity-dependent photocurrents are excited within the ab plane. This is consistent with earlier static photocurrent experiments, and demonstrates on the basis of both the physical constraints imposed by symmetry and the temporal dynamics intrinsic to current generation and decay that optically induced photocurrents in TaAs are inherent to the underlying crystal symmetry of the transition metal monopnictide family of Weyl semimetals.

[Severe acute pancreatitis with iatrogenic duodenal fistula: cause and minimal invasive treatment]

Objective: To investigate the causes and treatment of severe acute pancreatitis (SAP) with iatrogenic duodenal fistula. Methods: The clinical data of the SAP patients with duodenal fistula treated in the Severe Acute Pancreatitis Center of Sir Run Run Shaw Hospital from May 2015 to May 2018 was analyzed retrospectively. Results: A total of 11 patients were enrolled, among which 5 cases of duodenal fistula were caused by iatrogenic injury, including 2 cases of puncture injury, 2 cases of nutritional tube injury and 1 case of drainage tube injury. For patients with poor infection control after conservative treatment, laparoscopic assisted debridement through the right retroperitoneal approach was performed. Treatment of two patients failed for liver failure and the remaining patients were cured. Conclusions: Iatrogenic injury is one of the causes of duodenal fistula in patients with severe pancreatitis. Laparoscopic assisted debridement through the right retroperitoneal approach is an effective treatment for duodenal fistula.

Theoretical Study of the Addition of Cu-Carbenes to Acetylenes to Form Chiral Allenes

Terminal alkynes have become one of the most versatile building blocks for C-C bond construction in the past few decades, and they are usually considered to convert to acetylides before further transformations. In this study, a novel direct nucleophilic addition mode for Cu(I)-catalyzed cross-coupling of terminal alkynes and N-tosylhydrazones to synthesize chiral allenes is proposed, and it was investigated by density functional theory with the M11-L density functional. Three different reaction pathways were considered and investigated. The computational results show that the proposed reaction pathway, which includes direct nucleophilic attack of protonated acetylene, deprotonation of the vinyl cation, and catalyst regeneration, is the most favorable pathway. Another possible deprotonation-carbenation-insertion pathway is shown to be unfavorable. The direct nucleophilic addition step is the rate- and enantioselectivity-determining step in the catalytic cycle. Noncovalent interaction analysis shows that the steric effect between the methyl group of the carbene moiety and the naphthalyl group of the bisoxazoline ligand is important to control the enantioselectivity. In addition, calculation of a series of chiral bisoxazoline ligands shows that a bulky group on the oxazoline ring is favorable for high enantioselectivity, which agrees with experimental observations. Moreover, copper acetylides are stable, and their generation is a favorable pathway in the absence of chiral bisoxazoline ligands.

[Acquired blood coagulation factor Ⅴ deficiency in a patient with severe burn]

In March 2017, a severely burned male patient aged 36 years with hypovolemic shock was admitted to our hospital. The patient received large quantities of antibiotics and blood products and repeated skin graft after admission, and then he suffered wound errhysis and throat congestion. The patient was healthy before without family history of bleeding or thrombosis disease. Laboratory tests showed that prothrombin time and activated partial coagulation time were remarkably prolonged, blood coagulation factor Ⅴ activity was extremely low, and the result of qualitative test of coagulation factor inhibitor was positive. Acquired blood coagulation factor Ⅴ deficiency was diagnosed. After application of dexamethasone (5 mg, twice per day) and infusion of fresh frozen plasma, blood coagulation indicators of patients recovered in 4 days, the result of qualitative test of coagulation factor inhibitor was negative, and bleeding symptoms were improved.