Neurovascular territories of the canine fossa: Analysis of a South African population.

BACKGROUND: The canine fossa, a depression on the surface of the maxillary bone, is important clinically due to the nexus of the neurovascular elements which occur in this region and supply the superficial and deep structures of the face. While it is known that there is much variation in the neurovascular structures of this region, little is known about sex differences. The aim of this study was to investigate and map the neurovascular branching within the region of the canine fossa of a South African population, with particular reference to any sex differences. METHODS: Sixty hemifaces (n=30 female; n=30 male) of individuals between the ages of 40 and 100years were dissected. The origin, number of branches, connections between branches, origin of connecting branches and the distribution of the neurovascular structures associated with the mid-facial and canine fossa regions were documented. The data obtained was qualitative and was statistically analysed with SPSS v26 statistical analysis software. Frequency and contingency tables, along with Chi-squared analysis and Fischer's Exact test, were used for quantitative data analysis. RESULTS: While high levels of variation in the neurovascular elements were documented, there was no statistically significant variation between the sexes. A sex variation was only observed for the terminal branches of CN VII with females displaying a lower number of buccal nerve terminal branches than males. CONCLUSION: While only one sex difference of significance was found in the highly variable neurovascular structures resident in the region of the canine fossa, the variability of the neurovascular elements is of importance to surgeons.

From LASER physics to the para-hydrogen pumped RASER.

The properties of the LASER with respect to self-organization are compared with the key features of the p-H2 pumped RASER. According to LASER theory the equations of motion for the LASER can be derived from the enslaving principle, i.e. the slowest-changing order parameter (the light field in the resonator) enslaves the rapidly relaxing atomic degrees of freedom. Likewise, it is shown here that the equations of motion for the p-H2 pumped RASER result from a set of order parameters, where the transverse magnetization of the RASER-active spin states enslaves the electromagnetic modes. The consequences are striking for nuclear magnetic resonance (NMR) spectroscopy, since long-lasting multi-mode RASER oscillations enable unprecedented spectroscopic resolution down to the micro-Hertz regime. Based on the theory for multi-mode RASER operation we analyze the conditions that reveal either the collapse of the entire NMR spectrum, the occurrence of self-organized frequency-combs, or RASER spectra which reflect the J-coupled network of the molecule. Certain RASER experiments involving the protons of 15N pyridine or 3-picoline molecules pumped with p-H2 via SABRE (Signal Amplification By Reversible Exchange) show either a single RASER oscillation in the time domain, giant RASER pulses or a complex RASER beat pattern. The corresponding 1H spectra consist of one narrow line, equidistant narrow lines (frequency-comb), or highly resolved lines reporting NMR properties, respectively. Numerous applications in the areas of material sciences, fundamental physics and medicine involving high precision sensors for magnetic fields, rotational motions or molecular structures become feasible.

Analysis of parahydrogen polarized spin system in low magnetic fields.

Nuclear magnetic resonance (NMR) spectra of spin systems polarized either thermally or by parahydrogen exhibit strikingly different field dependencies. Thermally polarized spin systems show the well-known roof effect, observed when reducing magnetic field strengths which precludes the independent determination of chemical shift differences and J-coupling constants at low-fields. Quantum mechanical analysis of the NMR spectra with respect to polarization method, pulsed state preparation, and transition probabilities reveals that spectra of parahydrogen polarized systems feature an "inverse roof effect" in the regime where the chemical shift difference δν is smaller than J. This inverse roof effect allows for the extraction of both J-coupling and chemical shift information down to very low fields. Based on a two-spin system, the observed non-linear magnetic field dependence of the splitting of spectral lines is predicted. We develop a general solution for the steady state density matrix of a parahydrogen polarized three-spin system including a heteronucleus which allows explaining experimentally observed (1)H spectra. The analysis of three-spin density matrix illustrates two pathways for an efficient polarization transfer from parahydrogen to (13)C nuclei. Examination of the experimental data facilitates the extraction of all relevant NMR parameters using single-scan, high-resolution (1)H and (13)C NMR spectroscopy at low fields at a fraction of the cost associated with cryogenically cooled high-field NMR spectrometers.

Studies of 6Li-NMR properties in different salt solutions in low magnetic fields.

In this article we report the longitudinal relaxation times (T(1)) of various (6)Li salts ((6)LiI, (6)LiCl and (6)LiNO(3)) in D(2)O and H(2)O, measured in low magnetic fields (B(0)=3.5mT). This investigation serves the purpose of clarifying the relaxation behavior of different (6)Li solutions and different concentrations. The measurement were undertaken to establish a framework for future applications of hyperpolarized (6)Li in medical imaging, biological studies and investigations of lithium ion batteries. Time will pass during the transport of hyperpolarized lithium ions to the sample, which leads to a polarization loss. In order to store polarization as long as possible, it is necessary to examine which (6)Li salt solution has the longest relaxation time T(1). Longitudinal relaxation times of (6)Li salts in D(2)O and H(2)O were investigated as a function of concentration and the most extended T(1) was found for (6)LiI in D(2)O and H(2)O. In agreement with the theory the relaxation time T(1) of all (6)Li salts increase with decreasing concentration. In the case of (6)LiI in H(2)O an inverse behavior was observed. We assume that the prolonged T(1) times occur due to formation of (6)LiOH upon the solution of (6)LiI in H(2)O, which settles as a precipitate. By diluting the solution, the precipitate continuously dissolves and approaches T(1) of (6)LiOH (T(1)∼28s), leading to a shorter T(1) relaxation time.

Near-zero-field nuclear magnetic resonance.

We investigate nuclear magnetic resonance (NMR) in near zero field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J coupling). This is in stark contrast to the high-field case, where heteronuclear J couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectra. Experimental results are in good agreement with first-order perturbation theory and with full numerical simulation when perturbation theory breaks down. We present simple rules for understanding the splitting patterns in near-zero-field NMR, which can be applied to molecules with nontrivial spectra.

Imaging of a mixture of hyperpolarized 3He and 129Xe.

With the use of hyperpolarized gases, a great number of experiments have been carried out in order to improve the diagnostics of the lung, both from a structural and a functional point of view. 3He is best suited for structural studies, whereas 129Xe gives more detailed information about the functionality of the lung because it enters the bloodstream. In this work, we propose the use of a gas mixture to perform consecutive analysis of lung structure and functionality upon the delivery of a single bolus of gas. We show images of a helium-xenon gas mixture in the presence of a small amount of liquid toluene in order to demonstrate how both nuclei can be detected independently, extracting the spectroscopic information provided by the 129Xe spectra and obtaining an image with high sensitivity for 3He. A second experiment performed on a dissected mouse lung was used to demonstrate how the mixture of gases can enhance sensitivity in the larger airways of the lung.

Time resolved spectroscopic NMR imaging using hyperpolarized 129Xe.

We have visualized the melting and dissolution processes of xenon (Xe) ice into different solvents using the methods of nuclear magnetic resonance (NMR) spectroscopy, imaging, and time resolved spectroscopic imaging by means of hyperpolarized 129Xe. Starting from the initial condition of a hyperpolarized solid Xe layer frozen on top of an ethanol (ethanol/water) ice block we measured the Xe phase transitions as a function of time and temperature. In the pure ethanol sample, pieces of Xe ice first fall through the viscous ethanol to the bottom of the sample tube and then form a thin layer of liquid Xe/ethanol. The xenon atoms are trapped in this liquid layer up to room temperature and keep their magnetization over a time period of 11 min. In the ethanol/water mixture (80 vol%/20%), most of the polarized Xe liquid first stays on top of the ethanol/water ice block and then starts to penetrate into the pores and cracks of the ethanol/water ice block. In the final stage, nearly all the Xe polarization is in the gas phase above the liquid and trapped inside the pores. NMR spectra of homogeneous samples of pure ethanol containing thermally polarized Xe and the spectroscopic images of the melting process show that very high concentrations of hyperpolarized Xe (about half of the density of liquid Xe) can be stored or delivered in pure ethanol.

Inactivation of bacteriophages in water by means of non-ionizing (UV-253.7 nm) and ionizing (gamma) radiation: a comparative approach.

Thc inactivation behaviour of the bacteriophages PHI X 174 (ssDNA virus). MS2 (ssRNA virus) and B40-8 (dsDNA) toward non-ionizing (UV-253.7 nm) as well as to ionizing radiation (gamma radiation) was studied in order to evaluate their potential as viral indicators for water disinfection by irradiation. Previous findings of the high UV-253.7 nm resistance of MS2 were confirmed whereas an unexpected high sensitivity to gamma radiation compared to the two other phages was found. On the other hand, PHI X 174 revealed an enhanced UV sensitivity but a high resistance to ionizing radiation. B40-8 had an intermediate position between the other two bacteriophages relative to both types of radiation. As expected, the data of E. coli reconfirmed the unreliability of fecal indicator bacteria for the purpose of predicting responses of viruses to water treatment. In UV disinfection the influence of water matrix may be adequately controlled by considering the UV (253.7 nm) absorption of the water whereas so far no such parameter has existed for the influence of the water quality on ionizing irradiation with respect to the scavenger concentration.

Measurement of rubidium and xenon absolute polarization at high temperatures as a means of improved production of hyperpolarized (129)Xe.

We report on a rubidium-xenon (Rb-Xe) polarization unit for the continuous production of large quantities of hyperpolarized (129)Xe. The unit includes two diagnostic systems which enable the absolute measurement of both the (85)Rb and (129)Xe polarization in situ and at high temperatures. The Rb diagnostic system allows the measurement of one- or two-dimensional images of the absolute Rb polarization and thus enables the experimental study of light penetration into the optical pumping cell. The equilibrium Xe polarization measured in the optical pumping cell and in the freezing unit is typically approximately 20%, under optimal flowing conditions, and this is much lower than the volume-averaged rubidium polarization.

[Late outcome of severed extensor tendons in the area of the hand and fingers]. / Spätergebnisse bei Beugesehnendurchtrennungen im Hand- und Fingerbereich.

In the care and further treatment of patients with hand injuries, a necessary requirement of the hand surgeon is that he be able to cope with the interlocking factors that are no longer influential, for example, the type and extent of the trauma or the age of the patient; the influential factors are a thought-out care plan, atraumatic action with regard to optimal restoration of the hand. This also showed a retrospective analysis of results and post-examination from flexor tendon injuries in the hand of 298 patients, who were surgically cared for from 1984 to 1994 at the surgical clinic of the University of Jena. Of the 298 patients 119 patients with 198 flexor tendon injuries (165 fingers and 33 thumbs) were followed up. For objective assessment of the treatment results, the assessment scheme Buck-Gramcko was used.