Organophosphine as an Alkyl Transfer Shuttle for the Direct ß-Alkylation of Chalcones Using Alkyl Halides.

We report an efficient alkyl transfer strategy for the direct ß-alkylation of chalcones using commercially available alkyl bromides as alkyl reagents. In this transformation, the ortho-phosphanyl substituent in the chalcones is crucial for controlling their reactivity and selectivity. It also serves as a reliable alkyl transfer shuttle to transform electrophilic alkyl bromides into nucleophilic alkyl species in the form of quaternary phosphonium salts and transfer the alkyl group effectively to the ß-position of the chalcones. This alkyl transfer strategy can be further extended to the alkenylation of ortho-phosphanyl benzaldehydes to assemble functionalized polyenes.

Therapeutic effects and perspective of stem cell extracellular vesicles in aging and cancer.

Senescent cells can secrete a plethora of cytokines which induce senescent phenotype of neighboring cells and was called senescence-associated secretory phenotype. Previously, it was believed that cancer was caused by the infinite division and uncontrolled proliferation of cells. Based on this, anticancer treatments were all aimed at killing cancer cells. Cancer is now considered an age-related disease. Cancer cells are not exogenous, but one of the worst results of injuries which initially induce cell senescence. Therefore, reversing cell senescence can fundamentally prevent and treat cancer. Though current anticancer treatments induce the cancer cells apoptosis, they induce senescence of normal cells at the same time, thus promoting the occurrence and development of cancer and forming a vicious circle. Extracellular vesicles (EVs) are nano-sized vesicles which partially mirror their parent cells. In the tumor microenvironment, EVs of senescent cells can change the expression profile of cancer cells, contributing to their resistance to chemotherapy. There is growing evidence indicates that stem cell EVs exert effective antiaging and anticancer actions by transferring functional microRNAs and proteins. This review will summarize the therapeutic role of stem cell EVs in reversing aging and cancer, which suggests the broad clinical application perspective.

Prion protein is required for tumor necrosis factor α (TNFα)-triggered nuclear factor κB (NF-κB) signaling and cytokine production.

The expression of normal cellular prion protein (PrP) is required for the pathogenesis of prion diseases. However, the physiological functions of PrP remain ambiguous. Here, we identified PrP as being critical for tumor necrosis factor (TNF) α-triggered signaling in a human melanoma cell line, M2, and a pancreatic ductal cell adenocarcinoma cell line, BxPC-3. In M2 cells, TNFα up-regulates the expression of p-IκB-kinase α/ß (p-IKKα/ß), p-p65, and p-JNK, but down-regulates the IκBα protein, all of which are downstream signaling intermediates in the TNF receptor signaling cascade. When PRNP is deleted in M2 cells, the effects of TNFα are no longer detectable. More importantly, p-p65 and p-JNK responses are restored when PRNP is reintroduced into the PRNP null cells. TNFα also activates NF-κB and increases TNFα production in wild-type M2 cells, but not in PrP-null M2 cells. Similar results are obtained in the BxPC-3 cells. Moreover, TNFα activation of NF-κB requires ubiquitination of receptor-interacting serine/threonine kinase 1 (RIP1) and TNF receptor-associated factor 2 (TRAF2). TNFα treatment increases the binding between PrP and the deubiquitinase tumor suppressor cylindromatosis (CYLD), in these treated cells, binding of CYLD to RIP1 and TRAF2 is reduced. We conclude that PrP traps CYLD, preventing it from binding and deubiquitinating RIP1 and TRAF2. Our findings reveal that PrP enhances the responses to TNFα, promoting proinflammatory cytokine production, which may contribute to inflammation and tumorigenesis.

Pigment epithelial-derived factor (PEDF)-triggered lung cancer cell apoptosis relies on p53 protein-driven Fas ligand (Fas-L) up-regulation and Fas protein cell surface translocation.

Pigment epithelium-derived factor (PEDF), a potent antiangiogenesis agent, has recently attracted attention for targeting tumor cells in several types of tumors. However, less is known about the apoptosis-inducing effect of PEDF on human lung cancer cells and the underlying molecular events. Here we report that PEDF has a growth-suppressive and proapoptotic effect on lung cancer xenografts. Accordingly, in vitro, PEDF apparently induced apoptosis in A549 and Calu-3 cells, predominantly via the Fas-L/Fas death signaling pathway. Interestingly, A549 and Calu-3 cells are insensitive to the Fas-L/Fas apoptosis pathway because of the low level of cell surface Fas. Our results revealed that, in addition to the enhancement of Fas-L expression, PEDF increased the sensitivity of A549 and Calu-3 cells to Fas-L-mediated apoptosis by triggering the translocation of Fas protein to the plasma membrane in a p53- and FAP-1-dependent manner. Similarly, the up-regulation of Fas-L by PEDF was also mediated by p53. Furthermore, peroxisome proliferator-activated receptor γ was determined to be the upstream regulator of p53. Together, these findings uncover a novel mechanism of tumor cell apoptosis induced by PEDF and provide a potential therapeutic strategy for tumors that are insensitive to Fas-L/Fas-dependent apoptosis because of a low level of cell surface Fas.

Equilibrium and dynamical properties of polymer chains in random medium filled with randomly distributed nano-sized fillers.

The effect of randomly distributed nano-sized fillers on the equilibrium and dynamical properties of linear polymers is studied by using off-lattice Monte Carlo simulation. Lennard-Jones interactions between polymers and fillers are considered. Results show that the statistical dimensions and dynamical diffusion of polymer are dependent on the polymer-filler interaction strength εpf. The mean square radius of gyration 〈RG(2)〉 shows a minimum at a critical polymer-filler interaction εpf*. The value of εpf* decreases with the increase in the polymer length or the concentration of fillers. The exponent ν in 〈RG(2)〉 ∼ N(2ν) is a typical value of self-avoiding walking chain at small εpf but it increases sharply to a bigger value at εpf > εpf*. The mean square displacement decreases with the increase in εpf. Moreover, the normal diffusion of the polymer at weak interactions changes to subnormal diffusion at moderate and strong attractions. We find that polymers diffuse in dilute filler regions at weak attraction and diffuse in dense filler regions at strong attraction.

[Development of a High Spectral Resolution UV Flat-Field Spectrograph].

As an important optical splitting element, grating is used in many different spectrometers and spectrographs. Spherical varied-line-spacing grating (SVLSG) is easily combined with array detectors to get a wide wavelength range of spectrums in one time, because it can focus the spectrums in approximately a plane. Therefore, it's widely used in many spectral instruments. We usually only know the central groove density of a commercial grating and its mounting parameters, while its line spacing parameters are unknown. Moreover, the mounting parameters are optimized within the whole using wavelength range of the grating. However, in most circumstances only part of the wavelength range is used. Therefore, the mounting parameters are not optimized for the needed wavelength range. Under this condition, in this article we developed a method based on the focusing theory of the flat-field grating and the mounting parameters the manufacture provided to deduce the line spacing parameters of the grating. With these parameters, we can optimize the detector position according to the wavelength range we need and ray tracing can be done to test the optical system. In this article we developed a high spectral resolution ultraviolet spectrograph, covering a wavelength range of 230-280 nm. The grating used in this spectrograph has a central groove density of 1 200 lines x mm(-1) and a designed wavelength range of 170-500 nm. We deduced the line spacing parameters of the grating and optimized the detector mounting parameters. Hollow cathode lamps of different elements were used to calibrate the spectrograph and test the spectral resolution of it. Wavelength calibration of the spectrograph has been done with the parameter fitting method, and the calibration accuracy is better than 0.01 nm. Results show the spectral resolution of the spectral graph is about 0.08 nm at 280.20 nm.

Study on the polymer diffusion in a media with periodically distributed nano-sized fillers.

The effect of nano-sized fillers on the equilibrium and dynamical properties of a linear polymer is studied by using off-lattice Monte Carlo simulation. Fillers are arranged periodically in the system with period d and Lennard-Jones interaction between polymer and fillers is considered. Results show that the statistical dimension and dynamical diffusion of the polymer are dependent on the polymer-filler interaction strength ɛ(pf) and the relative size between R(G0) and d, here R(G0) is the radius of gyration of polymer in dilute solution. Normal diffusion of polymer is always observed in the regime 2R(G0) > d. And the diffusion coefficient D is scaled with chain length N as D ~ N(-α), where the exponent α increases with ɛ(pf). Whereas in the regime 2R(G0) < d ≪ Nl0 with l0 the mean bond length of polymer, normal diffusion is observed only at ɛ(pf) < 2, but the polymer will be adsorbed on the fillers and cannot diffuse at ɛ(pf) > 2. In addition, we find that there is a critical interaction strength ɛ*(pf) = 2 in our model system.

[A method for time-resolved laser-induced breakdown spectroscopy measurement].

Laser-Induced Breakdown Spectroscopy (LIBS) is strongly time related. Time-resolved LIBS measurement is an important technique for the research on laser induced plasma evolution and self-absorption of the emission lines. Concerning the temporal characteristics of LIBS spectrum, a method is proposed in the present paper which can achieve micros-scale time-resolved LIBS measurement by using general ms-scale detector. By setting different integration delay time of the ms-scale spectrum detector, a series of spectrum are recorded. And the integration delay time interval should be longer than the worst temporal precision. After baseline correction and spectrum fitting, the intensity of the character line was obtained. Calculating this intensity with differential method at a certain time interval and then the difference value is the time-resolved line intensity. Setting the plasma duration time as X-axis and the time-resolved line intensity as Y-axis, the evolution curve of the character line intensity can be plotted. Character line with overlap-free and smooth background should be a priority to be chosen for analysis. Using spectrometer with ms-scale integration time and a control system with temporal accuracy is 0.021 micros, experiments carried out. The results validate that this method can be used to characterize the evolution of LIBS characteristic lines and can reduce the cost of the time-resolved LIBS measurement system. This method makes high time-resolved LIBS spectrum measurement possible with cheaper system.

OSW-1 triggers necroptosis in colorectal cancer cells through the RIPK1/RIPK3/MLKL signaling pathway facilitated by the RIPK1-p62/SQSTM1 complex.

BACKGROUND: Necroptosis has emerged as a novel molecular pathway that can be targeted by chemotherapy agents in the treatment of cancer. OSW-1, which is derived from the bulbs of Ornithogalum saundersiae Baker, exerts a wide range of pharmacological effects. AIM: To explore whether OSW-1 can induce necroptosis in colorectal cancer (CRC) cells, thereby expanding its range of clinical applications. METHODS: We performed a sequence of functional experiments, including Cell Counting Kit-8 assays and flow cytometry analysis, to assess the inhibitory effect of OSW-1 on CRC cells. We utilized quantitative proteomics, employing tandem mass tag labeling combined with liquid chromatography-tandem mass spectrometry, to analyze changes in protein expression. Subsequent bioinformatic analysis was conducted to elucidate the biological processes associated with the identified proteins. Transmission electron microscopy (TEM) and immunofluorescence studies were also performed to examine the effects of OSW-1 on necroptosis. Finally, western blotting, siRNA experiments, and immunoprecipitation were employed to evaluate protein interactions within CRC cells. RESULTS: The results revealed that OSW-1 exerted a strong inhibitory effect on CRC cells, and this effect was accompanied by a necroptosis-like morphology that was observable via TEM. OSW-1 was shown to trigger necroptosis via activation of the RIPK1/RIPK3/MLKL pathway. Furthermore, the accumulation of p62/SQSTM1 was shown to mediate OSW-1-induced necroptosis through its interaction with RIPK1. CONCLUSION: We propose that OSW-1 can induce necroptosis through the RIPK1/RIPK3/MLKL signaling pathway, and that this effect is mediated by the RIPK1-p62/SQSTM1 complex, in CRC cells. These results provide a theoretical foundation for the use of OSW-1 in the clinical treatment of CRC.

Polymer translocation through a gradient channel.

The translocation of polymer through a channel with a gradient interaction between the polymer and the channel is studied. The interaction is expressed by E = E0 + kx, where E0 is the initial potential energy at the entrance, x is the position of the monomer inside the channel, and k is the energy gradient. The mean first passage time τ is calculated by using Fokker-Planck equation for two cases (1) N > L and (2) N < L under the assumption that the diffusion rate D is a constant, here N is the polymer length and L is the length of channel. Results show that there is a minimum of τ at k = k(c) for both cases, and the value kc is dependent on E0 and driving force f. At large f, the scaling relation τ ∼ N is observed for long polymer chains. But the scaling relation is dependent on the energy gradient k for an unforced driving translocation.

Precise and comprehensive evaluation of perianal fistulas, classification and related complications using magnetic resonance imaging.

OBJECTIVE: This study aimed to comprehensively evaluate perianal fistulas and their related complications using magnetic resonance imaging (MRI). METHODS: We enrolled 115 eligible patients who underwent preoperative perianal MRI. Primary fistulas, internal and external openings, and related complications were evaluated using MRI. All fistulas were classified according to Park's classification, Standard Practice Task Force classification, St. James's grade, and the position of the internal opening. RESULTS: In total, 169 primary fistulas were detected in 115 patients; 73 (63.5%) patients had a single primary tract and 42 (36.5%) patients had multiple primary tracts, and 198 internal and 129 external openings were identified. Based on Park's classification, 150 (88.7%) primary fistulas were classified into the following types: intersphincteric (82, 54.7%), trans-sphincteric (58, 38.6%), suprasphincteric (8, 5.3%), extrasphincteric (1, 0.7%), and diffuse intersphincteric with trans-sphincteric (1, 0.7%) types. Based on St. James's grade, 149 fistulas were classified into grade 1 (52, 34.9%), grade 2 (30, 20.1%), grade 3 (20, 13.4%), grade 4 (38, 25.5%), and grade 5 (9, 6.1%). We detected 92 (54.4%) simple and 77 (45.6%) complex perianal fistulas and 72 (42.6%) high and 97 (57.4%) low perianal fistulas. Furthermore, we detected 32 secondary tracts in 23 (20.0%) patients and 87 abscesses in 60 (52.2%) patients. Levator ani muscle involvement and extensive soft tissue edema were detected in 12 (10.4%) and 24 (20.9%) patients, respectively. CONCLUSION: MRI is a valuable and comprehensive tool that can not only be used to determine the general condition of perianal fistulas but also to classify them and identify related complications.

[EUV flat field grating spectrometer and performance measurement].

A high-resolution extreme ultraviolet (EUV) spectrometer has been developed to diagnose the magnetically confined plasmas. A holographic spherical varied line spacing concave grating which provides a flat focal plane is used as the diffraction element working with the grazing incidence angle of 3 degrees. The nominal groove density is 1200 lines x mm(-1). A deeply cooled back-illuminated CCD camera is used as the spectra detector and a mechanical shutter is used to control the time of exposure. It covers the wavelength range of 5-50 nm with the CCD cameral moving along the spectra focal plane to cover different wavelength range interested. Spectrometer design is presented and it was tested by a Penning discharge light source. By the wavelength calibration, the actual parameters of the optical system were calculated and the wavelength accuracy is 0.003 nm. Results show that the spectral resolution is about 0.015 nm at 20 nm with the width of entrance slit opened at 30 microm, which agrees with the design goal.

[Measuring method of spatial and spectral distribution of hollow cathode lamp].

In the present paper, the authors propose a method to measure the spatial and spectral distribution of hollow cathode lamp by imaging spectrometer. A push-broom convex grating imaging spectrometer based on Offner system is presented, with wavelength range 400-1 000 nm, field angle 22 degrees and spectral resolution 2-3 nm. The spatial distribution of Hg hollow cathode lamp was measured for the first time; this gives the spatial intensity distribution for different wavelengths and spectral distribution at different positions, with high spatial and spectral resolution. Also the hyperspectral data under different working current condition was obtained in order to analyze the differences of the distribution. It will be a powerful tool for the spatial and spectral properties measurement of hollow cathode lamps and other kinds of light sources.

[The relationship between corneal lymphangiogenesis and inflammation index after corneal alkali injury].

OBJECTIVE: To discuss the relationship between corneal lymphangiogenesis and inflammation index (IF) in alkali burned corneas. METHODS: Experimental research. Rat corneal hemangiogenesis and lymphangiogenesis were examined by 5'-nase-alkaline phosphatase (5'-NA-ALP) double enzyme-histochemistry and whole mount immunofluorescence at 1 day, 3 days, and 1, 2, 3, 4, 5, 6, 7, 8 weeks after alkaline burns, and the blood vessel counting (BVC) and the lymphatic vessel counting (LVC) were recorded. The state of corneal inflammation was observed under the slit lamp and evaluated by inflammation index (IF) grading at the same time. Then, the association of LVC with IF was examined. In addition, eleven human alkali burned corneas were obtained from 11 patients undergoing corneal transplantation in Zhongshan Ophthalmic Center from January 2005 to June 2008. Corneal lymphangiogenesis was examined by lymphatic vessel endothelial receptor (LYVE-1) immunohistochemistry. The significance of the differences in IF, inflammatory cells counting, burn history, and age between two groups was analyzed by using paired student's t-test. RESULTS: New lymphatic vessels were present in rat alkali burned corneas. Corneal lymphangiogenesis developed 3 days after alkaline burns, reached the top 2 weeks after the injury, then decreased gradually, and disappeared at the end of the 5th week. Corneal lymphatics occurred behind corneal inflammation, but disappeared before corneal inflammation and hemangiogenesis. LVC was strongly and positively correlated with IF (r = 0.572, P < 0.01) after corneal alkaline burns. Among eleven human alkali burned corneas, corneal lymphatic vessels were present in 3 corneas. Compared with the other 8 cases without corneal lymphangiogenesis, the scores of IF was significantly higher (t = 3.28, P < 0.05), the inflammatory cells counting dramatically increased (t = 2.42, P < 0.05), but the age decreased significantly (t = 2.62, P < 0.05). However, the difference in burn history between two groups was not significant (t = 1.28, P > 0.05). CONCLUSION: Corneal lymphangiogenesis develops after alkaline-burns and correlates closely with inflammation index.

[Effects of benzalkonium chloride on MUC1 in human conjunctival epithelial cells].

OBJECTIVE: To investigate the effects of benzalkonium chloride (BAC), a preservative used in many ophthalmic topical solutions, on mucin1 (MUC1) in human conjunctival epithelial cells in vitro. METHODS: Cultured epithelial cells obtained from human conjunctiva were exposed to medium containing BAC solutions at 0.0100%, 0.0050%, 0.0010%, 0.0005% and 0.0001% concentrations for a period of 15 min. Cells were examined after treatment and 6, 12, 24, 48 and 72 h later. The relative expression of the MUC1 mucin gene was determined by conventional reverse transcription-polymerase chain reaction (RT-PCR). Monoclonal antibody for MUC1 was used in Western blot analysis to detect MUC1. RESULTS: Cell exposure to 0.0100% and 0.0050% BAC decreased the expression of MUC1 at gene level between 12 and 72 h after treatment. Cells treated with 0.0010% and 0.0005% BAC decreased the expression of MUC1 between 24 and 48 h after treatment, recovered 72 h after treatment. At protein level, cells exposed to 0.0100% BAC decreased MUC1 between 24 and 72 h, 0.0050% BAC between 12 and 72 h, 0.0010% BAC 72 h later. CONCLUSIONS: These results suggest that BAC induces decreased expression of MUC1 at both gene and protein levels. The mode of BAC-induced decreased expression of MUC1 is dose-dependent.

Study on the interfacial properties of polymers around a nanoparticle.

The interfacial properties of polymer chains on spherical nanoparticles are investigated using off-lattice Monte Carlo simulations. Results show that the number of adsorbed monomers increases whereas the number of adsorbed polymers decreases with increasing the polymer-nanoparticle interaction strength. The interfacial layer thickness is independent of the nanoparticle size and chain length. The interfacial monomers exhibit layering behaviors with three distinct layers. The mobility of monomers in the innermost layer is strongly dependent on the polymer-nanoparticle interaction strength. The interfacial monomers always keep moving, and no glassy layer is present around the nanoparticle. Finally, our results show that the motion of nanoparticle can weaken the adsorption of polymers but does not change the conformational property of adsorbed polymers.

One-Pot Hydrothermal Synthesis of g-C3N4/BiPO4 Nanocomposites with Significant Photocatalytic Activity.

The g-C3N4/BiPO4 composites have been successfully synthesized via a one-pot hydrothermal process, which can be used to degrade the organic dyes (rhodamine B and methylene blue) under simulated sunlight irradiation. X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis diffuse reflectance spectra and Fourier transform infrared (FTIR) spectroscopy have been employed to characterize the samples. The g-C3N4/BiPO4 composites exhibited higher photocatalytic activity than pure BiPO4. And the optimum photocatalyst shows the outstanding photocatalytic activity, which exhibited 99.0% and 86.6% decolorization rate of RhB and MB, respectively.

Modifying the tumour microenvironment and reverting tumour cells: New strategies for treating malignant tumours.

The tumour microenvironment (TME) plays a pivotal role in tumour fate determination. The TME acts together with the genetic material of tumour cells to determine their initiation, metastasis and drug resistance. Stromal cells in the TME promote the growth and metastasis of tumour cells by secreting soluble molecules or exosomes. The abnormal microenvironment reduces immune surveillance and tumour killing. The TME causes low anti-tumour drug penetration and reactivity and high drug resistance. Tumour angiogenesis and microenvironmental hypoxia limit the drug concentration within the TME and enhance the stemness of tumour cells. Therefore, modifying the TME to effectively attack tumour cells could represent a comprehensive and effective anti-tumour strategy. Normal cells, such as stem cells and immune cells, can penetrate and disrupt the abnormal TME. Reconstruction of the TME with healthy cells is an exciting new direction for tumour treatment. We will elaborate on the mechanism of the TME to support tumours and the current cell therapies for targeting tumours and the TME-such as immune cell therapies, haematopoietic stem cell (HSC) transplantation therapies, mesenchymal stem cell (MSC) transfer and embryonic stem cell-based microenvironment therapies-to provide novel ideas for producing breakthroughs in tumour therapy strategies.

Reduction of Human DNA Contamination in Clinical Cerebrospinal Fluid Specimens Improves the Sensitivity of Metagenomic Next-Generation Sequencing.

Metagenomics next-generation sequencing (mNGS) is increasingly available for the detection of obscure infectious diseases of the central nervous system. However, human DNA contamination from elevated white cells, one of the characteristic cerebrospinal fluid (CSF) features in meningitis patients, greatly reduces the sensitivity of mNGS in the pathogen detection. Currently, effective approaches to selectively reduce host DNA contamination from clinical CSF samples are still lacking. In this study, a total of 20 meningitis patients were enrolled, including 10 definitively diagnosed tuberculous meningitis (TBM) and 10 definite cryptococcal meningitis (CM) cases. To evaluate the effect of reduced human DNA in the sensitivity of mNGS detection, three specimen-processing protocols were performed: (i) To remove human DNA, saponin, a nonionic surfactant, was used to selectively lyse white cells in CSF followed by DNase treatment prior to the extraction of DNA; (ii) to reduce host DNA, CSF was centrifuged to remove human cells, and the supernatant was collected for DNA extraction; and (iii) DNA extraction from the unprocessed specimens was set as the control. We found that saponin processing significantly elevated the NGS unique reads for Cryptococcus (P < 0.01) compared with the control but had no effects for Mycobacterium tuberculosis (P > 0.05). However, detection of centrifuged supernatants improved the NGS unique reads for both TBM and CM compared with controls (P < 0.01). Our results demonstrate that the use of mNGS of centrifuged supernatants from clinical CSF samples in patients with TBM and CM is a simple and effective method to improve the sensitivity of pathogen detection.

[BK virus and renal transplantation].

BK virus (BKV) is a subtype of papovaviridae. The latent and asymptomatic infection of BKV is common among healthy people. The incidence of BKV re-activation in renal transplant recipients ranges 10%-68%. About 1%-7% of renal transplant recipients will suffer from BKV-associated nephropathy (BKVAN), and half of them will experience graft failure. This paper summarizes the re-activation mechanism of BKV as well as the risk factors, pathology, diagnosis, and treatment of BKVAN.