Two new phenolic glucosides from Sphallerocarpus gracilis

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T cell–derived inducible nitric oxide synthase switches off TH17 cell differentiation

RORγt is necessary for the generation of TH17 cells but the molecular mechanisms for the regulation of TH17 cells are still not fully understood. We show that activation of CD4+ T cells results in the expression of inducible nitric oxide synthase (iNOS). iNOS-deficient mice displayed enhanced TH17 cell differentiation but without major effects on either TH1 or TH2 cell lineages, whereas endothelial NOS (eNOS) or neuronal NOS (nNOS) mutant mice showed comparable TH17 cell differentiation compared with wild-type control mice. The addition of N6-(1-iminoethyl)-l-lysine dihydrochloride (L-NIL), the iNOS inhibitor, significantly enhanced TH17 cell differentiation, and S-nitroso-N-acetylpenicillamine (SNAP), the NO donor, dose-dependently reduced the percentage of IL-17–producing CD4+ T cells. NO mediates nitration of tyrosine residues in RORγt, leading to the suppression of RORγt-induced IL-17 promoter activation, indicating that NO regulates IL-17 expression at the transcriptional level. Finally, studies of an experimental model of colitis showed that iNOS deficiency results in more severe inflammation with an enhanced TH17 phenotype. These results suggest that NO derived from iNOS in activated T cells plays a negative role in the regulation of TH17 cell differentiation and highlight the importance of intrinsic programs for the control of TH17 immune responses

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

Influence of Drying Conditions on the Durability of Concrete Subjected to the Combined Action of Chemical Attack and Freeze–Thaw Cycles

The durability of concrete is critical for the service life of concrete structures, and it is influenced by various factors. This paper investigates the impact of the relative humidity (RH) of the curing environment on the durability of five different concrete types. The aim is to determine a suitable approach for designing concrete that is well-suited for use in the salt lake region of Inner Mongolia. The concrete types comprise ordinary Portland cement (OPC), high-strength expansive concrete (HSEC), high-strength expansive concrete incorporating silica fume, fly ash, and blast furnace slag (HSEC-SFB), steel fiber-reinforced high-strength expansive concrete (SFRHSEC), and high elastic modulus polyethylene fiber-reinforced high-strength expansive concrete (HFRHSEC). All these concrete types underwent a 180-day curing process at three distinct relative humidities (RH = 30%, 50%, and 95%) before being subjected to freeze–thaw cycles in the Inner Mongolia salt lake brine. The curing environment with a 95% RH is referred to as the standard condition. The experimental results reveal that the durability of OPC and HSEC decreases significantly with increasing relative humidity. In comparison with the control sample cured in 95% RH, the maximum freeze–thaw cycles for concrete cured in lower RHs are only 31% to 76% for OPC and 66% to 77% for HSEC. However, the sensitivity of the durability of HSEC-SFB, SFRHSEC, and HFRHSEC to variations in RH in the curing environment diminishes. In comparison with the corresponding reference value, the maximum freeze–thaw cycles for samples cured in dry conditions increase by 14% to 17% for HSEC-SFB and 21% for SFRHSEC. Specifically, the service life of HFRHSEC cured in a low RH is 25% to 46% higher than the reference value. The durability of HSEC-SFB, SFRHSEC, and HFRHSEC has been proven to be appropriate for structures located in the salt lake region of Inner Mongolia

Flexural behavior of BMSC beam exposed to the harsh environment

Basic magnesium sulfate cement concrete (BMSC) was invented in 2013, which has many merits: excellent mechanical performance, good toughness and good crack resistance. But the mechanical performance of BMSC beams laid in the harsh weather for a long time is not known. The mechanical properties of six corroded reinforced BMSC beams were studied for applying this new concrete to practical engineering. It can be found that there is no rust crack before loading test. The bearing capacity of corroded reinforced BMSC beam laid in the harsh environment for two years, especially in the weather of long-term freeze-thaw cycles and acid rain, degraded by 11.9 % and the bending rigidity degraded by 17.0 %. Based on the attenuation of steel corrosion and deterioration of BMSC after the harsh exposure, the model of bearing capacity and cracking load of the corrosion-damaged BMSC beam is proposed. This paper is helpful to the application of BMSC members in the area of harsh environments

Primary meningeal melanocytoma of the anterior cranial fossa: a case report and review of the literature

Abstract Background Primary meningeal melanocytoma is a rare neurological disorder. Although it may occur at the base of the brain, it is extremely rare at the anterior cranial fossa. Case presentation A 27-year-old man presented with headache and diplopia at our department. Fundoscopy showed left optic nerve atrophy and right papilledema consistent with Foster-Kennedy syndrome. Neurological exams were otherwise normal. A left frontal irregular space-occupying lesion was seen on magnetic resonance imaging (MRI), and enhancement was shown on contrast-enhanced computed tomography (CT) scan. CT angiography (CTA) revealed vascular compression around the lesion. Prior to surgery, meningioma was diagnosed and gross tumor removal was performed. On postoperative pathohistological exam, the tumor proved to be a meningeal melanocytoma, WHO grade I. No skin melanoma was found. After surgery, the patient received radiation therapy. No tumor was seen on follow-up MR images six months after surgery. The patient was well after two and a half years, and there was no tumor recurrence on the follow-up CT. Conclusions This case of primary meningeal melanocytoma located at the anterior cranial fossa is very rare. Although primary meningeal melanocytoma is benign, it may behave aggressively. Complete surgical resection is curative for most cases. Radiation therapy is important to prevent relapse of the tumor, especially in cases of incomplete surgical resection.</p

On the 2-MRS Problem in a Tree with Unreliable Edges

This paper extends the well-known most reliable source (1-MRS) problem in unreliable graphs to the 2-most reliable source (2-MRS) problem. Two kinds of reachable probability models of node pair in unreliable graphs are considered, that is, the superior probability and united probability. The 2-MRS problem aims to find a node pair in the graph from which the expected number of reachable nodes or the minimum reachability is maximized. It has many important applications in large-scale unreliable computer or communication networks. The #P-hardness of the 2-MRS problem in general graphs follows directly from that of the 1-MRS problem. This paper deals with four models of the 2-MRS problem in unreliable trees where every edge has an independent working probability and devises a cubic-time and quadratic-space dynamic programming algorithm, respectively, for each model

Impact of Storage Temperature on Green Tea Quality: Insights from Sensory Analysis and Chemical Composition

This study investigated the impact of storage temperatures (−20 °C, room temperature, and 40 °C) on the sensory evaluation, metabolites, and volatile compounds of green tea stored for 12 months. The sensory evaluation revealed that tea samples stored at −20 °C retained their emerald green colour, tender aroma, and refreshing taste. Green tea biochemical constituents, including water extracts and total free amino acids, were measured by Chinese National Standard Methods (GB/T 8305-2013 and GB/T 8314-2013). Tea polyphenols and flavonoids were determined using spectrophotometric methods, while phytochemicals were detected using validated HPLC, and volatile compounds were detected using validated gas chromatography coupled with triple quadrupole mass spectrometry. The analysis showed that tea polyphenols were highest at −20 °C, and flavonoids were significantly reduced at higher temperatures. A similar trend was observed for amino acids, soluble sugar content, and water extracts. Tea catechins, including (-)-epigallocatechin-3-gallate (EGCG) and (-)-gallocatechin gallate (GCG), were highest at −20 °C, showing their susceptibility to temperature. A volatile compound analysis revealed distinct profiles with variations in the abundance of compounds, such as di-methyl sulfide, phenyl ethyl alcohol, indole, and benzaldehyde. This study identifies temperature-sensitive compounds, providing insights into the mechanisms underlying tea quality deterioration during storage