Rapid screening and visual tracing of melamine in soybean meal by NIR microscopy imaging

Near infrared microscopy imaging fers the opportunity to explore not only what lkinds ofchemical species are present at micro-scale level but also where the chemical species would bepr esent.By revealing the spectral and spatial information,the technique can identify and localizeany interested component.This study investigates the feasibility of using Near infrared mi.croscopy imaging to detect melamine in soybean meal.The results showed that 6805 cm^(-1) is verysensitive for melamine but not for soybean meal,so can be used for univariate analysis,Singlewavelength image and peak integr ation image at 6805 cm^(-1) are simple and efective met hods todetect the melamine in soybean meal.Furthermore,Principal Component Analysis is applied todetect the melamine in soybean meal.

Combining infrared and mode synthesizing atomic force microscopy： Application to the study of lipid vesicles inside Streptomyces bacteria

We propose a new analytical approach combining vibrational spectroscopy and acoustic tomography for the detection and characterization of vesicles inside Streptomyces bacteria. Using atomic force microscopy and infrared spectroscopy （AFM-IR）, we detect the presence of triglyceride vesicles. Their sizes in depth are measured with high accuracy using mode synthesizing atomic force microscopy （MS-AFM）. We conducted a comparative study of AFM-IR and MS-AFM, and highlighted the advantages of the coupling of these techniques in having a full characterization （chemical, topographical, and volumetric） of a biological sample. With these complementary techniques, a complete access to the vesicle size distribution has been achieved with an accuracy of less than 50 nm. A 3D reconstruction of bacteria showing the in-depth distribution of vesicles is given to underline the great potential of the acoustic method.

Effects of Different Concentrations and Exposure Time of Sodium Hypochlorite on the Structural,Compositional and Mechanical Properties of Human Dentin

This study evaluated the effects of sodium hypochlorite（NaOCl） with different concentrations and exposure time on the structural, compositional and mechanical properties of human dentin in vitro. Sixty dentin slabs were obtained from freshly extracted premolars, randomly distributed into four groups（n=15）, and treated with 1%, 5%, 10% NaOCl and distilled water（control group）, respectively, for a total of 60 min. Attenuated total reflection infrared（ATR-IR） spectroscopy, Raman spectroscopy and X-ray diffraction（XRD） were carried out before, 10 min and 60 min after the treatment. Scanning electron microscopy（SEM） and flexural strength test were conducted as well. The results showed that dentins experienced morphological alterations in the NaOCl groups, but not in the control group. Two-way repeated-measures analysis of variance revealed that the carbonate：mineral ratio（C：M）, Raman relative intensity（RRI）, a-axis, c-axis length and full width at half maximum（FWHM） with the increase of time and concentration in the NaOCl groups were not significantly different from those in the control group（P〉0.05）. Nevertheless, the mineral：matrix ratio（M：M） increased and the flexural strength declined with the increase of concentration and the extension of time in the NaOCl groups（P〈0.05）. Additionally, it was found that the M：M and the flexural strength remained unchanged after 1% NaOCl treatment（P〉0.05）, and the morphology changes were unnoticeable within 10 min in 1% NaOCl group. These results indicated that NaOCl has no significant effects on the inorganic mineral of human dentin; but it undermines and eliminates the organic content concentration-and time-dependently, which in turn influences the flexural strength and toughness of dentins. In addition, an irrigation of 1% NaOCl within 10 min can minimize the effects of NaOCl on the structural and mechanical properties of dentin during root canal treatment.

The research of typical microbial functional group reveals a new oceanic carbon sequestration mechanism——A case of innovative method promoting scientific discovery

Marine microbes are major drivers of marine biogeochemical cycles and play critical roles in the ecosystems. Aerobic anoxygenic phototrophic bacteria(AAPB) are an important bacterial functional group with capability of harvesting light energy and wide distribution, and appear to have a particular role in the ocean's carbon cycling. Yet the global pattern of AAPB distribution was controversial at the beginning of the 21 st century due to the defects of the AAPB enumeration methods. An advanced time-series observation-based infrared epifluorescence microscopy(TIREM) approach was established to amend the existing AAPB quantitative deviation and led to the accurate enumeration of AAPB in marine environments. The abundance of AAPB and AAPB% were higher in coastal and continental shelf waters than in oceanic waters, which does not support the idea that AAPB are specifically adapted to oligotrophic conditions due to photosynthesis in AAPB acting a supplement to their organic carbon respiration. Further investigation revealed that dependence of AAPB on dissolved organic carbon produced by phytoplankton(PDOC) may limit their competition and control AAPB distribution. So, the selection of carbon sources by AAPB indicated that they can effectively fractionate the carbon flow in the sea. Enlightened by these findings, the following studies on the interactions between marine microbes and DOC led to the discovery of a new mechanism of marine carbon sequestration—the Microbial Carbon Pump(MCP). The conceptual framework of MCP addresses the sources and mechanism of the vast DOC reservoir in the ocean and represents a breakthrough in the theory of ocean carbon sequestration.

Capuli cherry-mediated green synthesis of silver nanoparticles under white solar and blue LED light

In this article, the Capuli （Prunus serotina Ehrh. var. Capuli） cherry extract was used for the synthesis of silver nanoparticles （AgNPs） in the presence of white/visible solar and blue light-emitting diode （LED） light. For the characterization of the extract and the AgNPs, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy were employed, along with hydrodynamic particle size analysis, trans- mission electron microscopy and X-ray diffraction. The Ag nanospheres obtained using white light were 40-100 nm in diameter and exhibited an absorption peak at λmax= 445 nm, whereas those obtained using blue LED light were 20-80 nm in diameter with an absorption peak at λmax= 425 nm. Thermal analysis revealed that the content of biomolecules surrounding the AgNPs was about 55-65%, and it was also found that blue LED light AgNPs （56.28%, 0.05 mM） had a higher antioxidant efficacy than the white solar light AgNPs （33.42%, 0.05 mM） against l,l-diphenyl-2-picrylhydrazyl. The results indicate that obtaining AgNPs using a blue LED light may prove to be a simple, cost-effective and easily reproducible method for creating future nanopharmaceuticals.

Systematic study of Ce^(3+) on the structural and magnetic properties of Cu nanosized ferrites for potential applications

Ce^（3＋） substituted Cu-spinel nanoferrites CuCe_xFe_（2-x）O_4（x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10） were synthesized via sol-gel self-combustion hybrid route. Single phase spinel ferrite of Cu nanoferrites were examined using X-ray diffraction（XRD） analysis whereas the multiphase structure was observed as Ce contents increased from x=0.06. Field emission scanning electron microscopy（FESEM）, Thermogravimetric and differential thermal analysis（TGA and DTA） and Fourier transform infrared spectroscopy（FTIR） were used to find out the morphology phase and metal stretching vibrations of Ce^（3＋） substituted nanocrystalline ferrites. The crystallite size was increased and found in the range of 25-91 nm. The agglomerations in Cu ferrite samples increase as the Ce^（3＋） concentration increases. The magnetic properties such as remanence, saturation magnetization, coercivity, Bohr magneton and magnetocrystalline anisotropy constant（K） were determined using M-H loops recorded from a vibrating sample magnetometer（VSM）. Saturation magnetization, remanence and coercivity are increased as the Ce^（3＋）contents increase in Cu nanocrystalline samples. Moreover, law of approach to saturation（LoA） was used to calculate the maximum value of saturation for Ce-doped Cu nanoferrites. The soft magnetic behaviour of the Cu nanoferrite is observed as compared to the samples substituted with the increased Ce contents in Cu nanocrystalline ferrite. Bohr magneton and magnetocrystalline anisotropy are found to increase with the substitution of rare earth Ce^（3＋） contents in Cu spinel nanocrystalline ferrite. Cedoped Cu nanocrystalline ferrites with excellent properties may be suitable for potential applications in sensing, security, switching, core, multilayer chip inductor, biomedical and microwave absorption applications.

Utilization of nano/micro-size iron recovered from the fine fraction of automobile shredder residue for phenol degradation in water

The study investigates the magnetic separation of Fe from automobile shredder residue （ASR） （ 〈 0.25 mm） and its application for phenol degradation in water. The magnetically separated Fe was subjected to an ultrasonically assisted acid treatment, and the degradation of phenol in an aqueous solution using nano/micro-size Fe （n/m Fe） was investigated in an effort to evaluate the possibility of utilizing n/m Fe to remove phenol from wastewater. The prepared n/m Fe was analyzed by scanning electron microscopy （SEM） and Fourier transform infrared spectroscopy （FTIR）. The eflects of the dosages ot n/mFe, pH, concentration of phenol and amount of H2O2 on phenol removal were evaluated. The results confirm that the phenol degradation rate was improved with an increase in the dosages of n/mFe and H2O2; however, the rate is reduced when the phenol concentration is higher. The degradation of phenol by n/mFe followed the pseudo-first-order kinetics. The value of the reaction rate constant （k）was increased as the amounts of n/m Fe and H2O2 increased. Conversely, the value of k was reduced when the concentration of phenol was increased. The probable mechanism behind the degradation of phenol by n/m Fe is the oxidation of phenol through hydroxyl radicals which are produced during the reaction between H2O2 and n/m Fe.