Notes on the forest soil respiration measurement by a Li-6400 system

The correct method used in forest soil respiration measurement by Li-6400 is a premise of data quality control. According to the study in a larch plantation, collars should be inserted at 12 hours in advance to efficiently reduce the influence of CO2 spring-out.Moreover, collar insertion depth substantially affected soil respiration measurement, i.e. when collar was shallowly inserted into soil,transversal gas diffusion and the CO2 re-spring-out caused by unstable collars in the measurement could lead to overestimating soil respiration rate; however, when collar was deeply inserted into soil, root respiration decline caused by root-cut and the most active respiratory of the surface soil separated by the inserted collars could lead to underestimating soil respiration rate. Furthermore, an error less than 5% could be guaranteed in typical sunny day if the target [CO2] was set to the mean value of ambient [CO2] in most time of the day, but it should be carefully set in early morning and late afternoon according to changing ambient [CO2]. This protocol of measurement is useful in real measurement.

Molecular Insights into Distinct Membrane-insertion Behaviors and Mechanisms of 20 Amino Acids:an All-atom MD Simulation Study

Interfacial interactions of proteins with cell membranes play important roles in fundamental physiological processes of cells.The binding of proteins to membranes involves interactions between amino acids and membranes.However,the mechanism underlying amino acids'membrane behavior remains elusive.Herein,all-atom molecular dynamic simulations were applied to comprehensively investigating the molecular details of interactions between 20 amino acids with DOPC membranes.Our results show that 20 amino acids exhibit distinct membrane insertion activities,which are not simply determined by the side chain properties of amino acids.Aromatic Tyr/Phe/Trp,hydrophobic Val/Ile/Leu/Met,positively-charged Arg and hydrophilic Cys exhibit significantly strong membrane insertion capacities with different characteristic insertion depths and insertion angles.Surprisingly,hydrophobic Ala,positively-charged His/Lys,hydrophilic Asn/Ser/Gln/Thr,negatively-charged Asp/Glu and Pro/Gly have low membrane insertion capabilities.Considering the chemical structures and interaction details of amino acids with membranes,we suggest that the abundance and diversity of interaction sites and types,the synergistic effect of hydrophilic and hydrophobic interactions of amino acids with membranes and the structural flexibility of amino acids are key factors for determining membrane insertion capabilities and characteristics of amino acids.Our study sheds light on the atomic mechanism of interactions between single amino acids and membranes.

Thoughts on the conclusion of no differences between acupuncture and sham acupuncture in clinical researches of migraine in foreign countries

Aiming at the conclusion that ＂there is no difference in efficacy between acupuncture and sham-acupuncture＂ in clinical research field of migraine in foreign countries in recent years, through the discussions on the definition of sham acupuncture （placebo acupuncture）, the principles required to be obey in satisfactory placebo acupuncture, the definition, location, function as well as clinical results of shallow puncture, the authors probed into whether shallow puncture could be the control method of sham acupuncture （placebo acupuncture） in clinical research of acupuncture. It was demonstrated in the results that ＂acupuncture with minimal stimulation on skin superficial layer of meridian points or non-meridian points＂, the so-called control method of ＂sham acupuncture （placebo acupuncture）＂ excited holistic regulation of human body quite probably through ＂shallow puncture on cutaneous region of meridians＂ to achieve therapeutic effects. Hence, this method is not the appropriate control method of placebo acupuncture and cannot be the control method of sham acupuncture （placebo acupuncture） in clinical research of acupuncture. Therefore, it is naturally to repudiate the conclusion that ＂there is no difference in efficacy between acupuncture and sham acupuncture＂ in the research where this method is taken as the control of placebo acupuncture.