Theoretical Insight into the Au(I)-Catalyzed Intermolecular Condensation of Homopropargyl Alcohols with Terminal Alkynes: Reactant Stoichiometric Ratio-Controlled Chemodivergence

The mechanisms and chemoselectivities on the Au(I)-catalyzed intermolecular condensation between homopropargyl alcohols and terminal alkynes were investigated by performing DFT calculations. The reaction was indicated to involve three stages: transformation of the homopropargyl alcohol (R₁) via intramolecular cyclization to the cyclic vinyl ether (R₁'), formation of the C-2-arylalkynyl cyclic ether (P₁) via hydroalkynylation of R₁' with phenylacetylene (R₂), and conversion from P₁ to 2,3-dihydro-oxepine (P₂). The results revealed the origin of the reaction divergence and rationalized the experimental observations that a 1:3 reactant stoichiometric ratio affords P₁ as the major product, whereas the 1:1.1 ratio results in P₂ in high yield. The reactant stoichiometric ratio-controlled divergent reactivity is attributed to different catalytic activities of the gold catalyst toward different reaction stages. In the 1:3 situation, the excess R₂ induces the Au catalyst toward its dimerization and/or hydration, inhibiting the conversion of P₁ to P₂ and resulting in product P₁. Without excess R₂, the Au catalysis follows a general cascade reaction, leading to product P₂. Theoretical results described a general strategy controlling the reaction divergence by a different reactant stoichiometric ratio. This strategy may be enlightening for chemists who are exploring various synthesis methods with high chemo-, regio-, and enantioselectivities.

Computational study on the 1,3-diyne synthesis from gold(i)-catalyzed alkynylation of terminal alkynes with alkynyl hypervalent iodine reagents under the aid of a silver complex and 1,10-phenanthroline

DFT calculations reveal a new Au/Ag co-catalyzed π-activation mechanism for the formation of unsymmetrical 1,3-diyne.

Effect of Methylprednisolone on Liver Injury and Endotoxin Levels Following Brain Death in Rats

BACKGROUND AND AIM

Brain death impairs liver function in potential donors and is associated with inflammatory activation. Methylprednisolone treatment after brain death has been shown to reduce inflammatory activity. The aim of the present study was to evaluate the effects of methylprednisolone on liver injury and endotoxin levels in brain-dead rats.

METHODS

Thirty-two rats were randomly divided into 4 groups: a sham-operation group (Sham group), a brain death with methylprednisolone treatment group (Methy group), a brain death with saline treatment group (Saline group), and a brain death group (BD group). The rats were anesthetized and induced by gradually increasing the intra-cranial pressure using a Fogarty catheter balloon for brain death. All of the animals were observed and ventilated for 6 h prior to being euthanized. Hepatic pathologic histology (Knodell histology activity index), liver inflammatory cytokine levels, liver function and endotoxin levels were assessed.

RESULTS

After brain death, methylprednisolone markedly alleviated the Knodell histology activity index of liver injury (P < .05). Additionally, significant reductions in the levels of TNF-α, IL-1β, and IL-10 were observed in the Methy group compared to those in the Saline and BD groups (P < .01), whereas no significant differences were found between the Saline and BD groups (P > .05). Interestingly, although the rate of liver injury after brain death in the methylprednisolone treatment group improved, the endotoxin level did not decline in the Methy group compared to the levels in the Saline and BD groups (P > .05).

CONCLUSION

The present study verified that methylprednisolone was protective for liver injury in rats subjected to brain death. This protection appeared to be due to reduced inflammatory activity with no influence on the endotoxin level.

The fungal-resistance factors BmSPI38 and BmSPI39 predominantly exist as tetramers, not monomers, in Bombyx mori

Previous studies have indicated that trypsin inhibitor-like cysteine-rich domain (TIL)-type protease inhibitors, BmSPI38 and BmSPI39, suppress conidial germination and integument penetration of entomopathogenic fungi by inhibiting their cuticle-degrading proteases and might functions as fungal-resistance factors in the silkworm. To date, the physiological forms and functional significance of multimerization of BmSPI38 and BmSPI39 remain unknown. In this study, we investigated the physiological forms of BmSPI38 and BmSPI39 in Bombyx mori silkworms using multiple complementary methods, including activity staining, reducing and nonreducing sodium dodecyl sulfate polyacrylamide gel electrophoresis, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, western blotting and immunofluorescence. We found that recombinant BmSPI38 and BmSPI39 tend to form homologous multimers, and their dimers, trimers and tetramers possessed intense inhibitory activity against subtilisin A from Bacillus licheniformis. In contrast, their monomers showed no detectable inhibitory activity. Both BmSPI38 and BmSPI39 also exist mainly as stable tetramers in silkworm tissues, and they also predominantly function as a tetramer in these tissues. This study is the first to demonstrate this preferred quaternary form of a TIL-type protease inhibitor and will likely help to elucidate the mechanisms of BmSPI38 and BmSPI39 in the innate immune response of the silkworm.

Clerodane diterpenoids from the Chinese liverwort Jamesoniella autumnalis and their anti-inflammatory activity

Nine previously undescribed clerodane-type diterpenoids, jamesoniellides M-T and one ent-labdane-type diterpenoid, as well as one known analogue, were isolated from the Chinese liverwort Jamesoniella autumnalis (DC.) Stephani. Their structures were determined using MS, NMR spectroscopy, and electronic circular dichroism (ECD) calculations. Inhibition on LPS-induced NO production in RAW 264.7 murine macrophages was investigated, and the results showed that jamesoniellides Q-S exhibited moderate anti-inflammatory activity, with 50-80% maximum inhibition rate of NO production under the nontoxic tested concentration.

Wave propagation in tunable lightweight tensegrity metastructure

Lightweight metastructures are designed consisting of prismatic tensegrity building blocks which have excellent strength-to-weight ratio and also enable unique compression-torsion coupling. A theoretical model with a coupled axial-torsional stiffness is first developed to study the band structures of the proposed lightweight metastructures. Then, various unit cell designs are investigated for bandgap generations at desired frequency ranges. Broadband full-wave attenuation is found in the tensegrity metastructure with special opposite-chirality. Furthermore, tunable stiffness in the prismatic tensegrity structure is investigated and 'small-on-large' tunability is achieved in the metastructure by harnessing the geometrically nonlinear deformation through an external control torque. Prestress adjustment is also investigated for fine tuning of the band structure. Finally, frequency response tests on the finite metastructures are preformed to validate their wave attenuation ability as well as their wave propagation tunability. The proposed tensegrity metastructures could be very useful in various engineering applications where lightweight and tunable structures with broadband vibration suspension and wave attenuation ability are in high demand.

[Technical specification for clinical application of critical ultrasonography]

Critical ultrasonography(CUS) is different from the traditional diagnostic ultrasound, the examiner and interpreter of the image are critical care medicine physicians. The core content of CUS is to evaluate the pathophysiological changes of organs and systems and etiology changes. With the idea of critical care medicine as the soul, it can integrate the above information and clinical information, bedside real-time diagnosis and titration treatment, and evaluate the therapeutic effect so as to improve the outcome. CUS is a traditional technique which is applied as a new application method. The consensus of experts on critical ultrasonography in China released in 2016 put forward consensus suggestions on the concept, implementation and application of CUS. It should be further emphasized that the accurate and objective assessment and implementation of CUS requires the standardization of ultrasound image acquisition and the need to establish a CUS procedure. At the same time, the standardized training for CUS accepted by critical care medicine physicians requires the application of technical specifications, and the establishment of technical specifications is the basis for the quality control and continuous improvement of CUS. Chinese Critical Ultrasound Study Group and Critical Hemodynamic Therapy Collabration Group, based on the rich experience of clinical practice in critical care and research, combined with the essence of CUS, to learn the traditional ultrasonic essence, established the clinical application technical specifications of CUS, including in five parts: basic view and relevant indicators to obtain in CUS; basic norms for viscera organ assessment and special assessment; standardized processes and systematic inspection programs; examples of CUS applications; CUS training and the application of qualification certification. The establishment of applied technology standard is helpful for standardized training and clinical correct implementation. It is helpful for clinical evaluation and correct guidance treatment, and is also helpful for quality control and continuous improvement of CUS application.

Terpenoids with vasorelaxant effects from the Chinese liverwort Scapania carinthiaca

Four new diterpenoids scapanacins A-D (1-4) including one kaurane and three clerodane derivatives, along with eleven known compounds (9-15), were isolated from the Chinese liverwort Scapania carinthiaca J.B. Jack ex Lindb. Their structures were determined based on extensive spectroscopic analyses, and electronic circular dichroism (ECD) calculations. Vasorelaxant activity assays of the clerodane-type diterpenoids 2, and 4-8 revealed that they relaxed 3^rd-order rat mesenteric arterioles pre-contracted with norepinephrine (NE). Further assays with scapanacin D (4) confirmed that the vasodilatation was mediated through inhibition of Ca²⁺ influx via voltage-dependent Ca²⁺ channels (VDCs), and this Ca²⁺ channel blocking effect was also confirmed by inhibiting the extracellular Ca²⁺ influx in MOVAS cells. Besides, very little decrease of the relaxant activity caused by 4 on endothelium-denuded mesenteric arterioles with NE also suggested the vasodilatation was mainly produced by inhibiting Ca²⁺-induced contraction of smooth muscle. In addition, cytotoxicity testing showed that compounds 1 and 9 with α,β-unsaturated ketone exhibited inhibitory activities against a small panel of human cancer cell lines.

The Profile of Angiogenic Factors in Vitreous Humor of the Patients with Proliferative Diabetic Retinopathy

OBJECTIVE

To explore the expression profile of angiogenic factors associated with proliferative diabetic retinopathy (PDR).

METHODS

Undiluted vitreous humor samples were obtained from 10 diabetic patients with PDR (10 eyes) and 9 non-diabtic patients (9 eyes). The concentrations of 60 angiogenic factors in the vitreous humor samples were measured by RayBio Angiogenic Cytokine Antibody Array. Some differentially expressed factors were further confirmed in vitreous humor by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared with the non-diabetic controls, 20 differentially expressed factors with more than 1.50 fold changes were detected in patients with PDR. The median concentration of vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), angiopoietin (ANG)-1, ANG-2, urokinase-type plasminogen activator receptor (uPAR), Follistatin and matrix metalloproteinases 9 (MMP-9) was significantly increased in vitreous samples from PDR compared to controls (P < 0.05). However, (MCP)-1, Angiogenin and Leptin was significantly lower in PDR eyes compared to controls (P < 0.05). In the verification assay using ELISA, ANG-1, ANG-2, IL-6, VEGF, MMP-9, hepatocyte growth factor (HGF) and placenta growth factor (PIGF) concentration were increased in patients with PDR compared to controls (all P-values < 0.05).

CONCLUSION

This is the first report of a comprehensive multiplex analysis to identify angiogenic factors associated with PDR. These angiogenic factors may contribute to the pathogenesis of PDR and may be targets for therapeutic strategies of PDR.

[Primary carcinoid of ovary: a clinicopathologic analysis of 17 cases]

Objective: To study the clinicopathologic feature, diagnostic strategy and prognostic significance of primary carcinoid of the ovary (PCOTO). Methods: A series of 17 patients previously diagnosed as PCOTO at Department of Pathology, Peking Union Medical College Hospital during the period from 2002 to 2017 were evaluated with clinical data analysis, histopathology and immunohistochemistry, and the patients were followed up and the relevant literatures were reviewed. Results: The age of patients ranged from 24 to 64 years (mean, 42 years). Fourteen patients were found a pelvic mass for a health check-up, and only 3 patients presented with pain in the lower abdomen. The left ovary was involved initially in ten patients, and the right in seven. The major axis of the tumor ranged from 2 to 14 cm. The surface of these tumors was smooth. Seven of the tumors were solid-cystic, 6 were cystic and 4 were solid. Under light microscope, 6 cases were diagnosed as strumal carcinoid, 4 cases were insular carcinoid, 4 cases were trabecular carcinoid, 3 cases were insular and trabecular mixed type carcinoid and 1 case was mucinous carcinoid. The mitotic figures were no more than 1/10 HPF.There were 11 cases complicated with other ovarian tumors, including 10 cases with teratoma, and 1 case with mucinous cystic adenoma. The paraffin-embedded tissues of all cases showed immunoreactivity for NSE and Syn, and the positive propotion of CgA was 10/17. TTF1 was positive in thyroid follicles and negative in strumal carcinoid. The positive index of Ki-67 was no more than 2%. Follow-up of 13 to 188 months showed 16 patients without recurrence and 1 patients were loss to follow-up. Conclusions: PCOTO is very rare. Most of the patients are found with a mass during health check-up in unilateral ovary and without obvious clinical symptoms. Histologically, the tumor always exists with other ovarian tumors, including teratoma and mucinous cystic adenoma, with relatively good prognosis.

Multivariate computational analysis of biosensor's data for improved CD64 quantification for sepsis diagnosis

Sepsis, as a leading cause of death worldwide, relies on systemic inflammatory response syndrome (SIRS) criteria for its diagnosis. SIRS is highly non-specific as it relies on monitoring of patients' vitals for sepsis diagnosis, which are known to change with many confounding factors. Changes in leukocyte counts and CD64 expression levels are known specific biomarkers of pro-inflammatory host response at the onset of sepsis. Recently, we have developed a biosensor chip that can enumerate the leukocyte counts and quantify the neutrophil CD64 expression levels from a drop of blood. We were able to show improved sepsis diagnosis and prognosis in clinical studies by measuring these parameters during different times of the patients' stay in hospital. In this paper, we investigated the rate of cell capture with CD64 expression levels and used this in a multivariate computational model using artificial neural networks (ANNs) and showed improved accuracy of quantifying CD64 expression levels from the biosensor (n = 106 whole blood experiments). We found a high coefficient of determination and low error between biosensor- and flow cytometry-based neutrophil CD64 expression levels using multiple ANN training methods in comparison to those of univariate regression commonly employed. This approach can find many applications in biosensor data analytics by utilizing multiple features of the biosensor's data for output determination.

Theoretical Insight into the Mechansim and Origin of Ligand-Controlled Regioselectivity in Homogenous Gold-Catalyzed Intramolecular Hydroarylation of Alkynes

This work aims at understanding the mechanism and regioselectivity in ligand-controlled gold-catalyzed divergent intramolecular hydroarylation of alkynes reported by Jiang et al. ( J. Am. Chem. Soc. 2016 , 138 , 5218 - 5221 ). Focusing on a representative alkyne, N-propargyl-N-tosylaniline, we conducted a detailed computational study on the ortho- and para-position hydroarylation of the alkyne catalyzed by gold(I) catalysts with different ligands. Both the ortho- and para-position hydroarylation reactions are found to follow a similar three-stage mechanism: electrophilic cyclization, proton loss, and protiodeauration. The initial electrophilic cyclization was identified as the rate- and regiochemistry-determining step. With the flexible electron-deficient phosphite ligand, the ortho-position cyclization is identified as the energetically more favorable pathway, while with the rigid electron-abundant phosphine (Xphos) ligand, the dominant pathway turns to the para-position cyclization. The theoretical results are in good agreement with the experimental observations. The π-π interaction between alkynyl phenyl and the directing acylamino group are found to be mainly responsible for the observed ortho-selectivity, while a combination of favorable noncovalent CH···π interaction and steric repulsion between Xphos ligand and alkynyl group contributes to the observed exclusive para-selectivity. The present calculations provide deeper insight into the mechanism and origin of regioselectivity of the title reaction.

Glycan distribution and density in native skin's stratum corneum

Background

The glycosylation of proteins on the surface of corneocytes is believed to play an important role in cellular adhesion in the stratum corneum (SC) of human skin. Mapping with accuracy the localization of glycans on the surface of corneocytes through traditional methods of immunohistochemistry and electron microscopy remains a challenging task as both approaches lack enough resolution or need to be performed in high vacuum conditions.

Materials and methods

We used an advanced mode of atomic force microscope (AFM), with simultaneous topography and recognition imaging to investigate the distribution of glycans on native (no chemical preparation) stripped samples of human SC. The AFM cantilever tips were functionalized with anti‐heparan sulfate antibody and the lectin wheat germ agglutinin (WGA) which binds specifically to N‐acetyl glucosamine and sialic acid.

Results

From the recognition imaging, we observed the presence of the sulfated glycosaminoglycan, heparan sulfate, and the glycans recognized by WGA on the surface of SC corneocytes in their native state. These glycans were found associated with bead‐like domains which represent corneodesmosomes in the SC layers. Glycan density was calculated to be ~1200 molecules/μm² in lower layers of SC compared to an important decrease, (~106 molecules/μm²) closer to the surface due probably to corneodesmosome degradation.

Conclusion

Glycan spatial distribution and degradation is first observed on the surface of SC in native conditions and at high resolution. The method used can be extended to precisely localize the presence of other macromolecules on the surface of skin or other tissues where the maintenance of its native state is required.

Ophiosphaerellins A-I, Polyketide-Derived Compounds from the Endolichenic Fungus Ophiosphaerella korrae

Ophiosphaerellins A-I (1-9), the first example of bicyclo[4.1.0]heptenones, as well as their biosynthetic relatives ophiosphaerekorrins A-B (10-11) were isolated from the endolichenic fungus Ophiosphaerella korrae. Biosynthetically, they were derived from the polyketide pathway, and their absolute configurations were determined on the basis of the combination analysis of spectral data, circular dichroism calculations, and single-crystal X-ray diffraction measurement. Preliminary test with thin-layer chromatography bioautography found that this type of compounds showed moderate acetylcholinesterase (AChE) inhibitory effects.

Kirigami-based Elastic Metamaterials with Anisotropic Mass Density for Subwavelength Flexural Wave Control

A novel design of an elastic metamaterial with anisotropic mass density is proposed to manipulate flexural waves at a subwavelength scale. The three-dimensional metamaterial is inspired by kirigami, which can be easily manufactured by cutting and folding a thin metallic plate. By attaching the resonant kirigami structures periodically on the top of a host plate, a metamaterial plate can be constructed without any perforation that degrades the strength of the pristine plate. An analytical model is developed to understand the working mechanism of the proposed elastic metamaterial and the dispersion curves are calculated by using an extended plane wave expansion method. As a result, we verify an anisotropic effective mass density stemming from the coupling between the local resonance of the kirigami cells and the global flexural wave propagations in the host plate. Finally, numerical simulations on the directional flexural wave propagation in a two-dimensional array of kirigami metamaterial as well as super-resolution imaging through an elastic hyperlens are conducted to demonstrate the subwavelength-scale flexural wave control abilities. The proposed kirigami-based metamaterial has the advantages of no-perforation design and subwavelength flexural wave manipulation capability, which can be highly useful for engineering applications including non-destructive evaluations and structural health monitoring.

Cyperane and eudesmane-type sesquiterpenoids from Chinese liverwort and their anti-diabetic nephropathy potential

Six new sesquiterpenoids, including cyperane (1 and 2) and eudesmane (3–6) types, and one known eudesmane derivative (7), were isolated from the Chinese liverwort Chiloscyphus polyanthus var. rivularis (Schrad.) Nees. The structures of 1–7 were determined based on a combination of their spectroscopic data (NMR, HRESIMS and IR), single-crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Preliminary anti-diabetic nephropathy activity testing showed that the cyperane-type sesquiterpenoids could inhibit cell proliferation and extracellular matrix accumulation in high glucose cultured mesangial cells in a dose-dependent manner.

Six new sesquiterpenoids, including cyperane (1 and 2) and eudesmane (3–6) types, and one known eudesmane derivative (7), were isolated from the Chinese liverwort Chiloscyphus polyanthus var. rivularis (Schrad.) Nees.

Bibenzyl-Based Meroterpenoid Enantiomers from the Chinese Liverwort Radula sumatrana

Six new pairs of bibenzyl-based meroterpenoid enantiomers, (±)-rasumatranin A-D (1-4) and (±)-radulanin M and N (5 and 6), and six known compounds were isolated from the adnascent Chinese liverwort, Radula sumatrana. Their structures were elucidated based on spectroscopic data and chiral phase HPLC-ECD analyses. The structures of 1 and 7 were also confirmed by single-crystal X-ray diffraction analysis. Cytotoxicity tests of the isolated compounds showed that 6-hydroxy-3-methyl-8-phenylethylbenzo[b]oxepin-5-one (8) showed activity against the human cancer cell lines MCF-7, PC-3, and SMMC-7721, with IC₅₀ values of 3.86, 6.60, and 3.58 μM, respectively, and induced MCF-7 cell death through a mitochondria-mediated apoptosis pathway.

HMPA-Catalyzed One-Pot Multistep Hydrogenation Method for the Synthesis of 1,2,3-Trisubstituted Indolines

A convenient and facile method was developed for the synthesis of 1,2,3-trisubstituted indolines. Starting from indole derivatives and ketones/aldehydes, the corresponding indoline products could be obtained with high yield by the hexamethylphosphoramide (HMPA) catalyzed indole Friedel–Crafts reaction, reduction and direct reductive amination process.