Robot for Ligament Tensioning and Assessment of Spinal Stability

Study Design An in vitro human cadaveric biomechanics study. Objective A proof-of-concept study to quantify whether or not differences in segmental mobility associated with spinal instability could be detected by a robotic distraction system. Methods Testing was performed in fresh human cadaveric tissue. A prototype Robotic Middle Column Distractor was attached unilaterally to the pedicles of L3-4. Distraction forces up to 150 N were applied first in the intact state, and following discectomy of L3-4. Motions were recorded by time-indexed visual and fluoroscopic images, and analyzed to measure actual motions achieved. Functions of the robot unit were monitored during the procedure and evaluated qualitatively. Results A difference of 2.5 mm in z-axis motion was detected at 150 N load between the intact and post-discectomy states. The robot coupled with the image analysis method was able to clearly detect the difference between the intact (“stable”) and post-discectomy (“unstable”) spine. Data analysis of fluoroscopic images taken during the procedure showed greater motion than perceived by the investigators from qualitative review of visual data. All monitored robot functions performed within design parameters without error. Conclusion The study demonstrates the feasibility and utility of utilizing an intraoperative robotic distractor to measure the amount of spinal mobility present at a level. This could lead to an important clinical tool for both diagnostic functions as well as operative assist functions.

THE ISHANGO BONE: The World's First Known Mathematical Sieve and Table of the Small Prime Numbers

This paper aims to show that the Ishango bone, one of two bones discovered in the1950s buried in ash on the banks of Lake Edward in Democratic Republic of Congo(formerly Zaire), after a nearby volcanic eruption, is the world's first known mathematicalsieve and table of the small prime numbers. The bone is dated approximately 20,000BC.Key to the demonstration of the sieve is the contention that the ancient Stone Agemathematicians of Ishango in Central Africa conceived of doubling or multiplication by 2in a more primitive mode than modern Computer Age humans, as the process of"copying" of a singular record (that is, a mark created by a stone tool as encountered inStone Age people's daily experience). Similarly, the doubling of any number was, bylogical extension, a process of copying of any number of records (marks) denoting aninteger, thereby doubling the exhibited number (marks). Some evidence for this processof "copying" and thus representing numbers as consisting of "copies" of other numbers,is displayed on the bone and can still be found to exist in the number systems ofmodern Africans in the region.Unlike previous speculations on the use of the bone tool by other studies, the ancientmethod of sieving of the small primes suggested here is notable for unifying (making useand explanation of) all columns of the Ishango bone; whilst all numbers exhibited forman essential part of the primitive mathematical sieve described. Furthermore, it is statedthat the middle column (M) of the bone inscriptions houses the calculations of theIshango Sieve. All numbers deduced in the middle calculation column relate to aprocess of elimination of the non-prime numbers from the sequence of numbers1,2,3,4,5,6,7,8,9,10 (although numbers 1 and 2 are omitted). The act of elimination isproven by the display of the numbers deduced in the middle column; namely: 4, 6, 8, 9,and 10 and the subsequent omission of these same numbers from the following listleaving only: 5, 7 at the bottom of column M.This elimination process described above is repeated to obtain the primes 11,13,17,19when eliminating non-primes from the sequence 11,12,13,14,15,16,17,18,19,20.However, only calculations for the sequence 1 to 10 (for numbers above 2) aredisplayed in column M; as if to exemplify the Ishango Sieve method for the benefit ofposterity.

A Validated 2D-LC-UV Method for Simultaneous Determination of Imatinib and N-demethylimatinib in Plasma and Its Clinical Application for Therapeutic Drug Monitoring with GIST Patients

Background: The trough concentration (Cmin) of Imatinib (IM) is closely related to the treatment outcomes and adverse reactions of patients with gastrointestinal stromal tumors (GIST). However, the drug plasma level has great interand intra-individual variability, and therapeutic drug monitoring (TDM) is highly recommended. Objective: To develop a novel, simple, and economical two-dimensional liquid chromatography method with ultraviolet detector (2D-LC-UV) for simultaneous determination of IM and its major active metabolite, N-demethyl imatinib (NDIM) in human plasma, and then apply the method for TDM of the drug. Method: Sample was processed by simple protein precipitation. Two target analytes were separated on the one-dimension column, captured on the middle column, and then transferred to the two-dimension column for further analysis. The detection was performed at 264 nm. The column temperature was maintained at 40˚C and the injection volume was 500 μL. Totally 32 plasma samples were obtained from patients with GIST who were receiving IM. Method: Sample was processed by simple protein precipitation. Two target analytes were separated on the one-dimension column, captured on the middle column, and then transferred to the two-dimension column for further analysis. The detection was performed at 264 nm. The column temperature was maintained at 40˚C and the injection volume was 500 μL. Totally 32 plasma samples were obtained from patients with GIST who were receiving IM. Conclusion: The novel 2D-LC-UV method is simple, stable, highly automated and independent of specialized technicians, which greatly increases the real-time capability of routine TDM for IM in hospital.

STIFFNESS ANALYSIS AND OPTIMIZATION OF STEPPED COLUMNS UNDER COMBINED BENDING AND COMPRESSION

The paper presents the stiffness analysis and optimization of stepped columns constituting the core frame of the industrial building. The two-span cross section of a one- storey industrial building is investigated herein. The quasi-static calculation is performed using the limited load approximation method for the cross-section of the most loaded middle column. The critical Euler characteristic of the compressive longitudinal load is determined by the differential bending equations at the bifurcation instability in the column sections. The parameter optimization of the column cross-section is achieved through the nonlinear mathematical programming. The optimization of medium column cross-section is considered using the proposed calculation when setting a set of constraints for the optimization task.