A theoretical characterization method for non-spherical core-shell nanoparticles by XPS

Core-shell nanoparticles (NPs) are active research areas for their unique properties and wide applications. By changing the elemental composition in the core and shell, a series of core-shell NPs with specific functions can be obtained, where the sizes of the core and shell also influence the properties. X-ray photoelectron spectroscopy (XPS) is useful in this context as a means of quantitatively analyzing such NPs. The empirical formula proposed by Shard [J. Phys. Chem. C, 2012, 116(31), 16806-16813] for calculating the shell thickness of the spherical core-shell NPs has been verified by Powell et al. [J. Phys. Chem. C, 2016, 120(39), 22730-22738] through a simulation of XPS with Simulation of Electron Spectra for Surface Analysis (SESSA) software. However, real core-shell NPs are not necessarily ideal spheres; such NPs can have rich shapes and uneven thicknesses. This work aims to extend the Shard formula to non-ideal core-shell NPs. We have used a Monte Carlo simulation method to study the XPS signal variation with the shell thickness for several modeled non-spherical shapes of core-shell NPs including some complex geometric structures which are numerically constructed with finite-element triangular meshes. Five types of non-spherical shapes, i.e. egg, ellipsoid, rod, rough-surface, and star shapes, are considered, while the size parameters are varied over a wide range. The equivalent radius and equivalent thickness are defined to characterize the average size of the nanoparticles for the use of the Shard formula. We have thus derived an extended Shard formula for the specific core-shell NPs, with which the relative error between the predicted shell thickness and the real thickness can be reduced to less than 10%.

Improved reverse Monte Carlo analysis of optical property of Fe and Ni from reflection electron energy loss spectroscopy spectra

The energy loss functions (ELFs) of Fe and Ni have been derived from measured reflection electron energy loss spectroscopy (REELS) spectra by a reverse Monte Carlo analysis in our previous work. In this work, we present further improvements of ELFs for these metals. For Fe, we have updated ELFs at primary electron energies of 2 keV and 3 keV in a wider photon energy region (0-180 eV) with a better accuracy, which is verified by sum rules. Regarding to Ni, we supplement the ELF at primary energy of 5 keV and we also improve the data accuracy at 3 keV. Applying these new and more accurate ELFs we present the optical constants and dielectric functions for the two metals. The improvements were highlighted by comparing our present results with the previous data.

Optical properties of amorphous carbon determined by reflection electron energy loss spectroscopy spectra

We present the combined experimental and theoretical investigations of the optical properties of amorphous carbon. The reflection electron energy loss spectra (REELS) spectra of carbon were measured using a cylindrical mirror analyzer under ultrahigh vacuum conditions at primary electron energies of 750, 1000 and 1300 eV. The energy loss function and thereby the refractive index n and the extinction coefficient k were determined from these REELS spectra in a wide loss energy range of 2-200 eV by applying our reverse Monte Carlo method. The high accuracy of the obtained optical constants is justified with the ps- and f-sum rules. We found that our present optical constants of amorphous carbon fulfill the sum rules with the highest accuracy compared with the previously published data. Therefore, we highly recommend to replace the previous data with the present ones for practical applications. Moreover, we present the atomic scattering factors of amorphous carbon obtained from the dielectric function to predict its optical constants at a given density.

MicroRNA-466 with tumor markers for cervical cancer screening

Cervical cancer is the second most common cancer in women in the world. In this study, we explore tumor markers and microRNA-466 combination for cervical cancer screening. Tumor markers were measured by the methods of electro-chemiluminescent immunoassay and enzyme immunoassay. The microRNA-466 was performed by quantitative real-time polymerase chain reaction. Among normal group, hyperplasia group and cancer group, the CEA expression levels were 2.26 ng/ml, 3.85 ng/ml and 16.08 ng/ml, respectively. While the CA125 expression levels were 13.61 u/ml, 27.32 u/ml and 44.93 u/ml, respectively. The SCCA expression levels were 13.61 ng/ml, 27.32 ng/ml and 44.93 ng/ml, respectively. The expression levels of tumor markers were all gradually increased with the development of cervical lesions. The expression levels of microRNA-466 in cervical cancers (0.62) were greater than that in normal (0.076) and hyperplasia (0.24). The expression of microRNA-466 was correlated with lymphnode metastasis (P=0.000). There is a lower overall survival rate of patient with large tumor or lymphnode metastasis. Thus, the combination of tumor markers and microRNA-466 can be useful for early detection of cervical cancer and indicators for advanced stage and prognosis of the disease.

MiR-451 as a new tumor marker for gastric cancer

Gastric cancer is the second most common malignancy in China. However, the prognosis for gastric cancer patients remains poor. The purpose of this study was to investigate whether miR-451 was a potential prognostic biomarker for gastric cancer. Fresh tissues were immediately frozen in liquid nitrogen until use. The plasma was extracted and quantitative real-time polymerase chain reaction was performed to detect miR-451 expression. The Student's t test analysis and multivariate Cox regression analysis were performed to analyze expression of miR-451. The analysis results showed that the expression level of miR-451 was decreased expression in gastric cancer tissue. The down-regulation of miR-451 tended to be positively correlated with tumor stage, lymphatic metastasis and shorter overall survival of patients. MiR-451 may be a potential biomarker and a potential therapeutic target for the diagnoses and prognosis of gastric cancer.

Detection of New Delhi Metallo-Beta-Lactamase (Encoded by blaNDM-1 ) in Enterobacter aerogenes in China

BACKGROUND

The increase in bla_NDM-1 in Enterobacteriaceae has become a major concern worldwide. In previous study, we investigated clonal dissemination and mechanisms of resistance to carbapenem in China.

METHODS

We carried out retrospective surveillance for bla_NDM-1 among carbapenem-resistant enterobacter strains, which were isolated from patients at our hospital by bacterial strains selection, antimicrobial susceptibility testing, species identification, and molecular detection of resistance gene.

RESULTS

We found three bla_NDM-1 -positive isolates which were identified as Enterobacter aerogenes in clinical patients in China. The bla_NDM-1 -positive Enterobacter aerogenes isolates were first found.

CONCLUSION

It is important to mandate prudent usage of antibiotics and implement infection control measures to control the spread of these resistant bla_NDM-1 -positive strains.

Reference Intervals of Routine Coagulation Assays During the Pregnancy and Puerperium Period

BACKGROUND

Significant changes occur in the coagulation and fibrinolytic systems during pregnancy and puerperium in the plasma levels. However, reference ranges based on healthy people are not optimal for informing clinical decisions during the pregnancy and puerperium. Therefore, it is essential to explore coagulation assays' reference ranges during the pregnancy and puerperium.

METHODS

Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (Fib.), and D-dimer were all measured according to the manufacturer's specifications and laboratory standard operating procedure of the STA-R evolution coagulation analyzer. A total of 11,601 women were enrolled in this study.

RESULTS

The reference ranges for PT, APTT, TT, Fib., and D-dimer in nonpregnancy period were 10.87-13.76 s, 29.22-44.61 s, 15.39-20.15 s, 1.59-3.97 g/l, and 0-0.56 mg/l, respectively. In early-pregnancy period, the ranges were 11.14-14.07 s, 29.97-44.69 s, 14.92-19.03 s, 1.98-4.13 g/l, and 0-1.67 mg/l, respectively. In midpregnancy period, the ranges were 9.98-12.84 s, 28.53-40.70 s, 13.51-19.82 s, 2.63-5.19 g/l, and 0-2.81 mg/l, respectively. In late-pregnancy period, the ranges were 9.48-12.58 s, 28.61-40.80 s, 14.10-19.61 s, 2.80-5.56 g/l, and 0-27.08 mg/l, respectively. In puerperium period, the ranges were 10.85-13.72 s, 30.51-43.02 s, 15.31-19.64 s, 1.14-5.07 g/l, and 1.27-4.85 mg/l, respectively.

CONCLUSION

We presented reference intervals for coagulation assays from the nonpregnancy to puerperium period that can be adopted in other laboratories after further validation.

Newborn screening for congenital hypothyroidism in Henan province, China

BACKGROUND

Congenital hypothyroidism is the most common congenital endocrine disorder. The study aimed to determine the congenital hypothyroidism incidence by newborn screening programs in Henan Province, China.

METHODS

The screening programs for congenital hypothyroidism are based on the measurement of TSH in dried blood spots. The TSH concentration was measured in the dry blood spot specimen using a DELFIA fluoroimmunoassay. The TSH cutoff concentration was 8mU/l.

RESULTS

The total coverage and the incidence of congenital hypothyroidism were 24.85% (5,142,148/20,694,441) and 0.37‰ (1992/5,142,148), respectively. The coverage and the incidence of CH were only 0.58% (4526/784,580) and 0.22‰ (1/4526) in 1997, respectively. However, the coverage and the incidence of CH were increased to 74.67% (1,203,278/1,611,582) and 0.32‰ (389/1,203,278). There were no significant differences in the number of congenital hypothyroidism between males and females (P>0.05). The number of congenital hypothyroidism was increased year after year.

CONCLUSIONS

The newborn screening program for CH is successful and quite effective.

Epidemiology and genotype distribution of human papillomavirus (HPV) in women of Henan Province, China

BACKGROUND

Human papillomavirus (HPV) infection is the commonest sexually transmitted infection, which is associated with various clinical conditions. This study aimed to determine the distribution of HPV genotypes in the women of Henan Province, China.

METHODS

Cervical samples were collected by liquid-based method and consecutively evaluated cervical cytology and the presence of HPV DNA. Cytological classification was made according to the Bethesda 2001 criteria. HPV DNA was tested with xMAP technology by Luminex200™.

RESULTS

In cervical abnormalities, the infection rate of HPV was 84.0%, single type was 71.0%, multiple type was 13.0%, high risk HPV was 78.0% and low risk HPV was 8.0%. The most common genotypes found were HPV16, 52, 58, 33, 18, 6 and 39. The most common HPV genotypes were HPV16, 52, 6, 58 and 33 in NILM, HPV16, 52, 18, 58 and 6 in ASCUS, HPV52, 16, 58, 6 and 39 in LSIL, HPV16, 33, 58, 18 and 51 in HSIL, and HPV16, 18, 33, 58 and 52 in ICC, respectively. The prevalence of single HPV and multiple HPV was 64.8% and 13.3%, respectively. Age-specific prevalence of multiple HPV exhibited a "U" shaped curve.

CONCLUSIONS

Single HPV genotype infection was predominantly detected in different groups of cervical lesions in Henan Province, and HPV16, 52, 58, 33, 18 and 6 were the priority HPV types.

Simple co-electrodeposition of functionalized multi-walled carbon nanotubes/chitosan composite coating on mainspring for enhanced modulus of elasticity

Co-electrodeposition of functionalized multi-walled carbon nanotubes (f-MWCNTs) with chitosan was performed on pieces of a stainless steel mainspring. Under moderate conditions, composite coatings with controllable thickness from a few hundred nanometers to tens of micrometers can be achieved. After coating an 8 microm composite layer on a piece of mainspring 120 microm thick (i.e. 6.7% increase in thickness), the Young's modulus of the mainspring was found to have increased by more than approximately 25%. Moreover, the coated mainsprings possess much stronger mechanical strength as demonstrated by fatigue tests. The significant enhancement of Young's modulus and intrinsic strength are mostly attributed to the effect exerted by the subtle combination of chitosan and MWCNT. In the current study, the intensive cross-linkages formed between the -COOH groups in f-MWCNTs and the hydroxyl (-OH) and amino (-NH2) groups in chitosan were exploited. The chitosan molecular chains and f-MWCNTs both chemically react and physically knot with each other, leading to a three-dimensional interlaced f-MWCNT/chitosan composite coating. The reported co-electrodeposition provides a simple approach to form a stable, reproducible and rigid f-MWCNTs composite coating, which leads to the realization of a high-performance mainspring with reinforced mechanical strength.