Liver fibrosis index-based nomograms for identifying esophageal varices in patients with chronic hepatitis B related cirrhosis

BACKGROUND Esophageal varices(EV)are the most fatal complication of chronic hepatitis B(CHB)related cirrhosis.The prognosis is poor,especially after the first upper gastrointestinal hemorrhage.AIM To construct nomograms to predict the risk and severity of EV in patients with CHB related cirrhosis.METHODS Between 2016 and 2018,the patients with CHB related cirrhosis were recruited and divided into a training or validation cohort at The First Affiliated Hospital of Wenzhou Medical University.Clinical and ultrasonic parameters that were closely related to EV risk and severity were screened out by univariate and multivariate logistic regression analyses,and integrated into two nomograms,respectively.Both nomograms were internally and externally validated by calibration,concordance index(C-index),receiver operating characteristic curve,and decision curve analyses(DCA).RESULTS A total of 307 patients with CHB related cirrhosis were recruited.The independent risk factors for EV included Child-Pugh class[odds ratio(OR)=7.705,95%confidence interval(CI)=2.169-27.370,P=0.002],platelet count(OR=0.992,95%CI=0.984-1.000,P=0.044),splenic portal index(SPI)(OR=3.895,95%CI=1.630-9.308,P=0.002),and liver fibrosis index(LFI)(OR=3.603,95%CI=1.336-9.719,P=0.011);those of EV severity included Child-Pugh class(OR=5.436,95%CI=2.112-13.990,P<0.001),mean portal vein velocity(OR=1.479,95%CI=1.043-2.098,P=0.028),portal vein diameter(OR=1.397,95%CI=1.021-1.912,P=0.037),SPI(OR=1.463,95%CI=1.030-2.079,P=0.034),and LFI(OR=3.089,95%CI=1.442-6.617,P=0.004).Two nomograms(predicting EV risk and severity,respectively)were well-calibrated and had a favorable discriminative ability,with C-indexes of 0.916 and 0.846 in the training cohort,respectively,higher than those of other predictive indexes,like LFI(C-indexes=0.781 and 0.738),SPI(C-indexes=0.805 and 0.714),ratio of platelet count to spleen diameter(PSR)(C-indexes=0.822 and 0.726),King’s score(C-indexes=0.694 and 0.609),and Lok index(C-indexes=0.788 and 0.700).The areas under the curves(AUCs)of the two nomograms were 0.916 and 0.846 in the training cohort,respectively,higher than those of LFI(AUCs=0.781 and 0.738),SPI(AUCs=0.805 and 0.714),PSR(AUCs=0.822 and 0.726),King’s score(AUCs=0.694 and 0.609),and Lok index(AUCs=0.788 and 0.700).Better net benefits were shown in the DCA.The results were validated in the validation cohort.CONCLUSION Nomograms incorporating clinical and ultrasonic variables are efficient in noninvasively predicting the risk and severity of EV.

Anaphthalimide-based fluorescent probe for mercapto-containing compounds

A polarity-sensitive fluorescent probe MNP was rationally designed and synthesized with naphthalimide as the fluorophore and maleimide as the receptor for thiols. MNP is weakly fluorescent due to the photoinduced electron-transfer （PET） from the fluorophore to the receptor, and it displays evidently solvatochromic UV-vis and fluorescence spectra： the emission shifted from 495 nm in n-hexane to 545 nm in phosphate buffer solution. Michael addition reaction between thiols and the maleimide in MNP inhibited the PET process, which led to about eight-fold fluorescence enhancement. In addition, MNP showed highly sensitivity to rnercapto-containing proteins and it could detect as low as 20.4 μg/mL of BSA in PBS. MNP has potential in fluorescent imaging of thiols in living cells.

First-Principle Calculations of the MgYA_4(A=Co and Ni)Phase with AuBe_5-Type Structure

First-principles calculations have been performed to study the structural, mechanical and magnetic properties of the MgYCo4 and MgYNi4 phases in AuBes-type structure. The obtained values of cohesive energy as well as formation energy prove that the MgYCo4 and MgYNi4 phases have a good combination of structural stability and alloying ability, which is also supported by electronic structure. It is found that the magnetic moment of the MgYCo4 phase is 19.06 ktB per unit cell mainly owed to the 3d state of Co atom, and the MgYNi4 phase exhibits no magnetism. Both the trigonal shear constant C44 and the shear modulus G of the MgYNi4 phase are larger than those of the MgYCo4 phase. Plasticity of alloys has been estimated by the C11-C12 and Young＇s modulus E, and C12-C44, shear to bulk modulus ratio G/B and Poisson＇s ratio v have been studied to predict the ductility of alloys. According to the calculated results, the MgYCo4 phase has better plasticity as well as ductility, compared with the MgYNi4 phase.

Colorimetric and fluorimetric detection of cysteine: Unexpected Michael addition–elimination reaction

The synthesis of three isomers based on Michael addition mechanism for the detection of sulfurcontaining species in aqueous solution is described. These compounds are constructed by conjugating an enone to a coumarin fluorophore. A substituted-phenyl（o, m, or p-） was appended at the carbonyl carbon to adjust the reactivity. The experimental results showed that（E）-7-（diethylamino）-3-（3-（3-hydroxyphenyl）-3-oxoprop-1-en-1-yl）-2H-chromen-2-one（m-QPS） and（E）-7-（diethylamino）-3-（3-（4-hydroxyphenyl）-3-oxoprop-1-en-1-yl）-2H-chromen-2-one（p-QPS） barely react with sulfur-containing nucleophiles, while（E）-7-（diethylamino）-3-（3-（2-hydroxyphenyl）-3-oxoprop-1-en-1-yl）-2H-chromen-2-one（o-QPS） exhibited a fast response toward sulfite, sulfide and thiols in DMSO/phosphate buffer（2：1）. The above results are probably due to the intramolecular H-bonding activated Michael addition.More interestingly, cysteine triggered unusual photophysical responses of o-QPS： the original absorption（488 nm） and emission peaks（573 nm） underwent significant blue shifts initially and then recovered,which might be caused by the Michael addition and elimination reaction, respectively.

Discrimination of biothiols in different media with NBD-F as the probe

4-Fluoro-7-nitrobenzo-2-oxa-1,3-diazole（NBD-F） was employed as a colorimetric probe for differential detection of biothiols in different media. The spectral response and the selectivity of NBD-F toward thiols were significantly improved by surfactant micelles. Mercapto group exhibited high reactivity in all the solvents（including Tris–HCl buffer solution, CTAB and SDS micelles）. The 4-thioether derivatives of NBDF reacting with Cys and Hcy but not GSH could transfer to the corresponding 4-amino-substituents via intramolecular nucleophilic aromatic substitution, thus, GSH could be discriminated from Cys/Hcy. In CTAB micelles, the reaction product of NBD-F with Cys is non-fluorescent and it absorbs in longwavelength region. According to the spectral responses of NBD-F toward different low-molecularweight thiols, we could identify Cys, Hcy and GSH from each other.

Why is pollen in Camellia oleifera inedible to honeybees?

The evolutionary transition from bee-to bird-pollinated plants is usually associated with multiple modifications in floral traits,such as color,size,nectar and pollen presentation mode (Thomson and Wilson,2008).Compared to bee-adapted flowers,bird-flowers usually produce a larger volume of nectar with a lower sugar concentration(Sun et al.,2017).