Design and simulation of shear-tension spring-type quasi-zero stiffness isolator

By connecting the linear compression spring (positive stiffness mechanism) in parallel with the tension spring (negative stiffness mechanism) and using the shear lever mechanism to amplify the motion of the negative stiffness mechanism, a shear-tension spring type quasi-zero stiffness isolation system is constructed, which is suitable for low-frequency and ultra-low-frequency vibration isolation, especially for small-amplitude, low-frequency vibration isolation. In addition, the vibration isolation system has adjustable function. When the mass of the isolated object changes, it is needed to adjust the linear bearing at the bottom of the vertical spring to change the length of the spring, so as to keep the isolation system in the equilibrium position of the quasi-zero state. The results show that the isolator has excellent performance in isolation of low frequency vibration with small and micro amplitude

The human GCOM1 complex gene interacts with the NMDA receptor and internexin-alpha

The known functions of the human GCOM1 complex hub gene include transcription elongation and the intercalated disk of cardiac myocytes. However, in all likelihood, the gene's most interesting, and thus far least understood, roles will be found in the central nervous system. To investigate the functions of the GCOM1 gene in the CNS, we have cloned human and rat brain cDNAs encoding novel, 105 kDa GCOM1 combined (Gcom) proteins, designated Gcom15, and identified a new group of GCOM1 interacting genes, termed Gints, from yeast two-hybrid (Y2H) screens. We showed that Gcom15 interacts with the NR1 subunit of the NMDA receptor by co-expression in heterologous cells, in which we observed bi-directional co-immunoprecipitation of human Gcom15 and murine NR1. Our Y2H screens revealed 27 novel GCOM1 interacting genes, many of which are synaptic proteins and/or play roles in neurologic diseases. Finally, we showed, using rat brain protein preparations, that the Gint internexin-alpha (INA), a known interactor of the NMDAR, co-IPs with GCOM1 proteins, suggesting a GCOM1-GRIN1-INA interaction and a novel pathway that may be relevant to neuroprotection

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Effect of Astragali and Angelica particle on proteinuria in Chinese patients with primary glomerulonephritis

AbstractObjectiveTo investigate the effect of the traditional Chinese herbs Astragali and Angelicae Sinensis (A & As) particle [contains Huangqi (Radix Astragali Mongolica), Danggui (Radix Angelicae Sinensis), Huzhanggeng (Rhizoma Polygoni Cuspidati) and Danshen (Radix Salviae Miltiorrhizae)] on proteinuria in glomerulonephritis patients with stage 2 chronic kidney disease.MethodsA prospective, multi-center, and randomized controlled clinical trial was performed for 24 weeks. From March 2011 to April 2012, 158 patients from nine hospitals in China participated. They were randomized into the A&As group (79 cases, A&As particle 15.2 g/day) and losartan group (79 cases, losartan 50 mg/day). At each follow-up visit, clinical data including blood pressure, urinalysis, 24-h-urinary protein excretion, serum albumin and serum creatinine were collected.ResultsAll 158 patients completed the follow-up. Proteinuria in the losartan group exhibited a biphasic time-dependent decline with a significant steady reduction from baseline to week 12 (P = 0.0014), and a platform level during the remaining 12-week follow-up (P > 0.05). In contrast, there was a continual significant decrease of proteinuria in the A & As group (P < 0.001). When compared with the losartan results, proteinuria in the A & As group from week 16 to week 24 was significantly reduced (P < 0.001). Stable eGFRs and blood pressure were also observed in both groups. Medication side effects were minimal and non-fatal.ConclusionFor Chinese glomerulonephritis patients with stage 2 chronic kidney disease, therapy with A & As particles may provide effective anti-proteinuria treatment

Prototype of space-borne LTT module and its ground tests

In order to develop the technique of Laser Time Transfer (LTT), Shanghai Astronomical Observatory has built a prototype of space-borne LTT module. The performance of the LTT module and the results of ground tests are discussed in the paper. The average precision of time difference between two rubidium clocks measured by laser pulses is 196 ps, and the uncertainty of measurement for the relative frequency differences is 1.2x10(-13)/2800 s

Modular Synthesis of Functionalized Butenolides by Oxidative Furan Fragmentation

The development of new chemical transformations to simplify the synthesis of valuable building blocks is a challenging task in organic chemistry and has been the focus of considerable research effort. From a synthetic perspective, it would be ideal if the natural reactivities of feedstock chemicals could be diverted to the production of high value-added compounds which are otherwise tedious to prepare. Here we report a chemical transformation that enables facile and modular synthesis of synthetically challenging yet biologically important functionalized butenolides from easily accessible furans. Specifically, Diels–Alder reactions between furans and singlet oxygen generate versatile hydroperoxide intermediates, which undergo iron(II)-mediated radical fragmentation in the presence of Cu(OAc)2 or various radical trapping reagents to afford butenolides bearing a wide variety of appended remote functional groups, including olefins, halides, azides and aldehydes. The practical utility of this transformation is demonstrated by easy diversification of the products by means of cross-coupling reactions and, most importantly, by its ability to simplify the syntheses of known building blocks of eight biologically active natural products

Bioactive thionic compounds and aromatic glycosides from Ligusticum chuanxiong

Three new thionic compounds, (S)-2-(2-carboxyl-2-hydroxyethylthio)-ferulic acid (1), (E)-2-methoxy-4-(3-(methylsulfonyl)prop-1-en-1-yl)phenol (2), and thiosenkyunolide C (3), together with two new aromatic glycosides (4 and 5) were isolated from the rhizome of Ligusticum chuanxiong Hort. Two known compounds (6 and 7) were also obtained. Their structures were elucidated based on extensive spectroscopic data (UV, IR, 1D and 2D NMR, and HR-ESI-MS). Furthermore the absolute configurations were established by comparison of their calculated and experimental circular dichroism spectra and by a dimolybdenum tetraacetate [Mo2(AcO)4]-induced circular dichroism procedure. All compounds were evaluated against lipopolysaccharide (LPS)-induced NO production in BV2 cells, and compounds 4 and 5 showed strong inhibitory activities with IC50 values of 2.03 and 3.09 µmol/L, respectively (positive control curcumin, IC50 = 6.17 µmol/L). In addition, compound 1 showed weak proteintyrosine phosphatase-1B (PTP1B) inhibitory activity. KEY WORDS: Ligusticum chuanxiong Hort., Thionic compounds, Aromatic glycosides, Anti-inflammatory, Natural product

Caffeic Acid Phenethyl Ester Reduces Hypoxia-Induced Reactive Oxygen Species and Mitigatates Inflammation in Corneal Endothelial BCE C/D-1b Cells

Oxygen supply is crucial to the health of avascular human cornea where low-oxygen-transmissible soft contact lenses often cause keratitis upon excessive wear time. Caffeic acid phenethyl ester, an active component of propolis, has anti-oxidative and anti-inflammatory properties. This study investigated the in vitro effects of caffeic acid phenethyl ester on corneal inflammation and its underlying action. We measured NF-κB activity and Dichloro-dihydro-fluorescein diacetate staining to demonstrate that caffeic acid phenethyl ester ameliorates hypoxia-induced inflammation of corneal endothelial cells and reactive oxygen species formation. The results may provide a new strategy to mitigate keratitis by caffeic acid phenethyl ester treatment