Auto-offsetting and -referencing in biomolecular NMR experiments

A frequency ratio RatioXH associated with two carrier frequencies in ppm is introduced for achieving auto-offsetting and -referencing (AOR) in biomolecular NMR. Once the center of 1H is referenced, all the offsets in other dimensions are automatically determined and the centers of the spectral widths provide accurate indirect references. Since the scale in ppm is independent of the magnetic field strength, the AOR does not require manually updating carrier frequencies from time to time, making the multidimensional NMR experiments greatly simplified and reliable. It is extremely valuable when molecules need to be run a large number of experiments at different times and the data (chemical shifts, for example) need to be compared with each other. In AOR, the error arising from improper referencing of 1H is handed down in the same amount to the other nuclei being referenced. This error-inheritance provides a measure of accuracy in indirect referencing. The temperature dependence of the frequency ratio of DSS is derived with the first-order approximation and it can be used for temperature dependent AOR. For nuclei other than 13C, certain frequency ratios regarding TMS need to be derived (rather than measured) based on the recommended frequency ratios of DSS, thus avoiding conflicts and unifying the two standards.

Method for differential phase delay resolution of phase referencing VLBI technique and its experimental verification

The phase referencing Very Long Baseline Interferometry(VLBI)technique is a newly developed tool to measure the angular position of a deep space exploration probe in the plane-of-the-sky.Through alternating observations between the probe and a nearby reference radio source,their accurate relative angular separation can be obtained from the radio images generated by this technique.To meet the requirements of the current orbit determination software,differential delay should be firstly derived from those radio images.A method to resolve the differential phase delay from the phase referencing VLBI technique is proposed in this paper,and as well the mathematical model for differential phase ambiguity resolution is established.This method is verified with practical measurement data from the Chang’E-3 mission.The differential phase delay between the Chang’E-3 lander and rover was derived from the phase referencing VLBI measurements,and was then imported into the Shanghai astronomical observatory Orbit Determination Program(SODP)to calculate the position of the rover relative to the lander on the lunar surface.The results are consistent with those acquired directly from radio images,indicating that the differential phase ambiguity has been correctly resolved.The proposed method can be used to promote applications of the phase referencing VLBI technique in future lunar or deep space explorations,and more accurate orbit determination becomes promising.

Dissemination network of referencing errors:A comparison between the two most cited papersin the world

Lowry's paper(1951,Journal of Biological Chemistry)is the most highly cited paper in the world up to 26th,December 2022.Laemmli's paper(1970,Nature)ranks second.These two papers are selected as our sample to compare respective dissemination networks of referencing errors.There are several types of referencing errors,and we focus on the so-called'double error",that is,the co-occurrence of a wrong volume number of a journal and a wrong beginning page number of a paper.Since the probability of a double error is extremely small,so that whenever double error occurs more than once,we can deduce definitely that there are some authors who copy references from the reference list of other publications.Based on the dissemination networks of the double errors of the above-mentioned two papers,three dissemination routes are confirmed.Route 1:copying references from another paper and citing that paper.Route 2:copying references from another paper without citing that paper.Route 3:Sharing at least one author with another paper which carries the same referencing error.Some suggestions are offered to reduce or eliminate the misconduct of copying references without any checking.

Designing“Useful”Reading Assessment for Engineering Students

The purpose of designing the assessment is to drive curriculum development and learning,and to promote students’inference making ability when reading at the college level.The focal construct of this study is inference making based on text information and the reader’s background knowledge.Therefore,reading in the assignment means reading between the lines to learn the implied underlying meaning.This study applies a principled,theory-based approach to develop reading assessment.Test specification is made at the end.