Carbon,Nitrogen,and Sulfur Contents in Marine Phytoplankton Cells and Biomass Conversion

In this study,we isolated and cultured phytoplankton along the coast of China and measured the cellular carbon,nitrogen,and sulfur contents under four temperatures.The results showed that the contents of the cellular elements varied widely among different phytoplankton.We found that temperature is one of the important factors affecting the carbon,nitrogen,and sulfur contents in phytoplankton cells;however,the degree of influence of temperature is different for different kinds of phytoplankton.By measuring the nitrogen content in cells,we found that the C:N ratio indirectly measured in the experiment fluctuated in the range of 3.50-8.97,and the average C:N ratio was 5.52.In this experiment,we accurately measured the cell elemental contents at different temperatures and transformed the cell count results into carbon,nitrogen,and sulfur contents to express the biomass.This method ensures that the contribution of species that are small in number but with a large cell volume in biomass is considered.Moreover,this method comprehensively considers the interspecific differences of species and the uneven distribution of elements in phytoplankton cells,which is of significance in the estimation of marine carbon and nitrogen budget.The distribution of nitrogen content in marine phytoplankton can well indicate the marine eutrophication caused by human activities.Climate change can affect the community structure and element composition of marine phytoplankton,meanwhile marine carbon and nitrogen element can regulate the climate to a certain extent.

Influence of boron contents on properties of AlMgB films prepared by RF magnetron sputtering

Ternary AlMgB thin films were synthesized on silicon (100) substrate at 573 K by radio frequency (RF) magnetron sputtering method using one Al/Mg co-target and one boron target. The thickness of the as-deposited thin film was controlled to 500 nm by adjusting deposition time. The influences of sputtering powers on the elemental contents and structural and mechanical properties were investigated by electron probe microanalysis (EPMA), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), and nanoindentation system. At the same time, the ball-on-disk tribometer was used to measure the friction behavior of the films. Experimental results indicate that the as-deposited boron-rich films are primarily amorphous structure and possess a dramatic high hardness up to 39 GPa with 99.03 at.% boron. Obviously, it has exceeded the hardness value of 32 GPa of pure AlMgB 14 bulk material prepared by sintering method. Furthermore, the friction coefficients of the thin films exhibit an average value as low as 0.3, which is considered as the effect of self-lubricating.

Comparison of 66 chemical element contents in normal and benign hyperplastic prostate

Objective:The aim of this study was to clarify the differences between the prostatic levels of chemical elements in patients with benign prostatic hyperplasia(BPH)and healthy male.Methods:We evaluated the prostatic level of 66 chemical elements in 43 patients with BPH and 37 healthy males.Measurements were performed using five instrumental analytical methods.Results:In the hyperplastic prostates,we have observed a significant increase in the mean level of Bi,Cr,Hg,K,Sb,and Se accompanied a significant decrease in the mean level of Al,Ce,Cs,Dy,Er,Gd,Ho,La,Mo,Nd,Pb,Pr,Sm,Sn,Tb,Tm,U,and Y.No differences were found in the mean prostatic level of other chemical elements including Ag,Al,Au,B,Ba,Be,Br,Ca,Cd,Co,Cu,Fe,Li,Mg,Mn,Na,Nb,Ni,P,Rb,S,Sc,Si,Th,Ti,Tl,Yb,Zn,and Zr between BPH patients and healthy males.Conclusions:The finding of chemical element contents and correlation between pairs of chemical element mass fractions indicates that there is a great disturbance of prostatic chemical element metabolism in BPH gland.Trace elements Bi,Cr,Hg,K,Sb,and Se may be regarded as the possible tissue biomarkers of hyperplastic transformation of prostate gland.Obtained data did not confirm a critical role of Cd and Pb accumulation in the pathogenesis of BPH.A potential age-related Zn,Fe,and Se deficiency in the prostate tissue has not been found as being involved in the etiology of BPH.

Using LA-ICP-MS to analysis elemental composition of statoliths of Scyphozoan jellyfish

Scyphozoan jellyfish outbreak events are drawing increasing attentions during the past decade.Elemental compositions of statoliths are helpful to understand jellyfish life history and blooming mechanisms,but very rare endeavor has been focused on the Scyphozoan class.In this work,we explored the feasibility of element analysis of Aurelia aurita(a representative Scyphozoan jellyfish outbreak species in China)which may be used as proxies of environment parameters during jellyfish living and moving.Statolith crystals of Aurelia aurita were found to be a gathering of hexahedron type trigonal needle with size of 10-50μm long,and 5-10μm in diameter.By using laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS)downhole profiling method,elements such as Ca,Sr,Mg,Na and P were found to be above the limit of detection and limit of quantification.The epidermis of statocyst could significantly impact the element analyses,so the real statolith element signal section needs to be selected based on elements and Ca profiles together with care.By laser ablated a signal spot repeatedly,the analytical uncertainty was about 3%-4%for Sr/Ca content ratio and Mg/Ca content ratio,but above 10%for other element/Ca content ratios(n=3).Based on the analysis of statolith from temperature-control cultured jellyfish,Sr/Ca content ratios among different statoliths of the same jellyfish were about 6%(n=14),demonstrating biological processes/vital effects causing small variations compared with analytical uncertainties.Therefore,Sr/Ca content ratios may be used as a potential proxy to reveal the living environment variations the Scyphozoan jellyfish has experienced,such as temperature history,which is helpful to understand jellyfish bloom mechanisms.