Ion Behavior in an Electrically Compensated Ion Cyclotron Resonance Trap

A PERSPECTIVE ON PERSONAL CONTRIBUTIONS TO FT-ICR MASS SPECTROMETRY

This is a personal perspective on our contributions to FT-ICR, many of early ones in a collaboration with Charles Wilkins and Michael Gross starting in the mid-1970s and then continuing for many years in collaboration of Don Rempel and Michael Gross. The perspective is to honor Alan Marshall, who with Melvin Comisarow, first demonstrated FT-ICR MS in 1974 (Comisarow & Marshall, 1974 ). Our intention is to review the contributions made together with Wilkins, Rempel, and a group of graduate and postdoctoral students, starting at the University of Nebraska-Lincoln and continuing here at Washington University in St. Louis. Besides offering a chance to reminisce about the early and exciting days of FT-ICR MS when academic laboratories were building and modifying mass spectrometers and other instruments, a nearly lost art, I am reminded of my editorship of this journal occurring over part of that time.

Physiotherapeutic Reduction of Orofacial Pain Using Extremely Low-Frequency Electromagnetic Field and Light-Emitting Diode Therapy-A Pilot Study

INTRODUCTION

Pain is a natural response of the body to injury and one of the symptoms defining an inflammatory reaction. It is almost always present after orthognathic surgeries (OGS), but its severity is subjective in each patient. Postoperative care of the patient is aimed at minimizing of postoperative pain relief orofacial region. Options of physiotherapy include extremely low-frequency electromagnetic field (ELF EMF) and high-energy light-emitting diode (LED). Aim of the Study. The aim of this study was to evaluate the effects of physiotherapy combining ELF EMF and LED to reduce pain of the orofacial region in patients after OGS. Material and Methods. The study was conducted in thirty-two patients who underwent OGS to treat morphological defects. The participants were randomly divided into two groups: Physiotherapy group (PT) and Control group (CG). In both groups, patients were prescribed Paracetamol and nonsteroidal analgesics (NSAID-ibuprofen). Patients from the PT group additionally received postoperative physiotherapy immediately after leaving the surgical clinic in the form of ELF EMF and LED therapy. Physiotherapeutic treatments were performed for 10 days, three applications a day, at no cost to the patient. Pain intensity was assessed using the visual analogue scale (VAS), which is a reliable instrument for the measurement of pain intensity self-reported by the patient.

RESULTS

Faster reduction of pain was the major observation made in patients who received physiotherapy treatments. In all subjects, after 5 days of therapy, the pain intensity was reduced by about 50% or resolved completely. Effects of therapy were measured with the relative changes in the pain intensity score, showing what fraction of the initial pain was eliminated at the first stage and throughout the whole therapy. The analysis of relative changes instead of absolute changes allowed us, among other things, to eliminate the bias of the higher initial pain intensity in the CG group compared to the PT group.

CONCLUSIONS

The conducted research revealed that the combined use of ELF EMF and LED is beneficial in the reduction of pain of patients after OGS. The analgesic effects of physiotherapy in the treatment after OGS are necessary to continue research in this area and analyze the possibility of extending the indications for its use in other surgically treated maxillofacial diseases.

Twelve million resolving power on 4.7 T Fourier transform ion cyclotron resonance instrument with dynamically harmonized cell--observation of fine structure in peptide mass spectra

Resolving power of about 12,000 000 at m/z 675 has been achieved on low field homogeneity 4.7 T magnet using a dynamically harmonized Fourier transform ion cyclotron resonance (FT ICR) cell. Mass spectra of the fine structure of the isotopic distribution of a peptide were obtained and strong discrimination of small intensity peaks was observed in case of resonance excitation of the ions of the whole isotopic cluster to the same cyclotron radius. The absence of some peaks from the mass spectra of the fine structure was explained basing on results of computer simulations showing strong ion cloud interactions, which cause the coalescence of peaks with m/z close to that of the highest magnitude peak. The way to prevent peak discrimination is to excite ion clouds of different m/z to different cyclotron radii, which was demonstrated and investigated both experimentally and by computer simulations.

Use of an artificial immune system derived method for the charge state assignment of small-molecule mass spectra

Knowing the charge state of an ion in a mass spectrum is crucial to being able to assign a formula to it. For many small-molecule peaks in complex mass spectra, the intensities of the isotopic peaks are too low to allow the charge state to be calculated from isotopic spacings, which is the basis of the conventional method of determining the charge state of an ion. A novel artificial intelligence derived method for identifying the charge state of ions, in the absence of any isotopic information or a series of charge states, has been developed using an artificial immune system approach. This technique has been tested against synthetic and real data sets and has proven successful in identifying the majority of multiply charged ions, thereby significantly improving the peak assignment rate and confidence.