How to evaluate scar colour after burn injuries - A clinical comparison of the Mexameter® and the subjective scar assessment (POSAS/VSS).

INTRODUCTION: Scarring after burn injuries remains one of the major challenges in burn medicine and is the subject of current research. Accurate and high-quality assessment of scars is needed to enable exact outcome evaluation of different treatments. Our aim was to evaluate the most common subjective scar evaluation scores-the POSAS (Patient and Observer Scar Assessment Scale) and VSS (Vancouver Scar Scale)-in comparison with the objective device Mexameter® for colour evaluation. METHODS: A prospective monocentre study was performed, which included 120 examined scar areas of 60 patients with third degree burns who had received skin grafts between 1975 and 2018 with a total burned surface area (TBSA) > 2%. Two different scar areas in comparison with one healthy skin area concerning 'colour', 'pigmentation', and 'vascularization' were evaluated by the Mexameter® MX 18, the OSAS, and the VSS by the same examiner, as well as the PSAS by the patient. RESULTS: The mean TBSA of the 60 patients was 24.3%. In the OSAS, 61% of the scars were evaluated as 'hyper-', 19% as 'hypo-', and 19% as 'mix-pigmented'. Furthermore, 65% of the scars were estimated as highly vascularized. In the Mexameter®, the melanin index values of the scar areas compared to the healthy skin areas showed a small difference of 12 (p < 0.05). The mean difference of erythema between the scar and the healthy skin areas was 84 (p < 0.001). For the Mexameter®, moderate correlations were found when comparing 'erythema' with the OSAS category 'vascularization' (r = 0.33, p < 0.05) and 'melanin' with the OSAS parameter 'pigmentation' (r = 0.28, p < 0.05). When comparing the Mexameter® measurements to the OSAS questionnaire, 27% of the scars were wrongly evaluated as 'hyperpigmented' by the observer and 21% as 'hypervascularized', while showing low measurements in the device. Additionally, a novel Mexameter® ordinal scare scale was calculated. CONCLUSION: In this study, we were able to show on a relatively large patient population that with the Mexameter®, the subjectivity of the scar colour assessment by examiner/patient can be overcome, but precise differentiation can still be ensured with subjective evaluation tools. We further introduced a novel Mexameter® Scar Scale. It is necessary to further investigate the vast range of objective devices and develop scar panels for with an incorporation of objective and subjective devices to further improve reliability with reduced bias in terms of scar assessment.

Enantioseparation and a comprehensive spectroscopic analysis of novel synthetic cathinones laterally substituted with a trifluoromethyl group.

Recently, the number of structural modifications of synthetic cathinones has been growing making them the second largest group of new psychoactive substances in Europe. Although they are abused because of their various psychoactive effects, some compounds from this group also serve as pharmaceuticals. Since synthetic cathinones are chiral molecules with one chiral center, their biological, toxicological, and pharmacological properties may significantly differ according to their absolute configuration and enantiomeric excess. In this study, we have synthesized two substances bearing a pharmacologically interesting trifluoromethyl group and developed a chiral liquid chromatography method using a polysaccharide chiral stationary phase to separate the corresponding enantiomers of both these drugs. Subsequently, we utilized molecular spectroscopic methods including chiroptical (electronic circular dichroism and vibrational circular dichroism) and non-polarizable (infrared and ultraviolet absorption) spectroscopies. In combination with density functional theory calculations, we have obtained stable conformers of selected enantiomers in solution and their relative abundances, which we used to simulate their spectra. The experimental and calculated data have been used to elucidate the 3D structure of the enantiomerically pure compounds and assign the absolute configuration of all prepared compounds.

Localization and Delocalization in Solids from Electron Distribution Functions.

The extent of electron localization and delocalization in molecular and condensed phases has been the subject of intense scrutiny over the years. In Chemistry, where real, instead of momentum space viewpoints are many times closer to intuition, a plethora of localization descriptors exist, including a family of indices invariant under orbital transformations that rely only on an underlying partition of the physical space into meaningful regions. These localization and delocalization indices measure the fluctuation of the electron population contained in such domains, and have been rigorously related to the insulating or conductive character of extended systems. Knowledge of the full electron population probability distribution function is also available in molecules, where it has provided many meaningful results as well as uncovered exotic interaction regimes in excited states. Electron distribution functions (EDFs), which can be seen as real space analogs of Pauling resonance structures, are now reported in periodic systems. In agreement with what is known in finite systems, ionic compounds display narrow EDFs that get wider as covalency sets in. Contrarily to conventional wisdom, most electrons delocalize over their nearest neighbors, even in quasi electron-gas metals like sodium, and it is only in the decay rate of the probability distribution where conductors and insulators can be distinguished.

Synthesis of upper rim-double-bridged calix[4]arenes bearing seven membered rings and related compounds.

Meta/meta- and meta/para-disubstituted organomercury calix[4]arenes in the cone conformation were transformed into corresponding amino derivatives. Acylation and subsequent intramolecular cyclization using the Bischler-Napieralski reaction provided, in the case of the meta/meta-series, double bridged calixarenes possessing seven membered rings on the upper rim. A similar synthetic strategy applied to meta/para-isomers allowed for the isolation of monobridged compounds bearing an additional trifluoroacetamido group located distally to seven-membered rings. Both series represent inherently chiral systems, which were successfully resolved using preparative chiral HPLC. The pure enantiomers exhibited a recognition ability towards selected chiral guest molecules as documented by the 1H NMR titration experiments. The absolute configuration of the phenyl-substituted enantiomer (meta/meta-) was confirmed by single crystal structure determination (X-ray).

Silica gel-immobilized multidisciplinary materials applicable in stereoselective organocatalysis and HPLC separation.

In this pilot study, we present novel bifunctional silica gel-immobilized materials applicable as heterogeneous organocatalysts and stationary phases in HPLC. The materials provided high stereoselectivity in both batch and continuous flow catalysis of a model Michael addition (cyclohexanone to (E)-ß-nitrostyrene). In the batch reaction, the catalysts proved their sustainable catalytic activity over five consecutive recycling experiments. Under continuous flow reaction conditions, the catalytic activity was found to be superior to the batch reaction, and moreover, the same immobilized materials were utilized as stationary phases in HPLC showing very good chemoselective separation of model acidic analytes.

System for time-resolved laser absorption spectroscopy and its application to high-power impulse magnetron sputtering.

This paper deals with the development and construction of an apparatus for time-resolved tunable diode laser absorption spectroscopy (LAS) for the diagnostics of pulsed plasma. A detailed description of the extension of a progressive method of laser absorption spectroscopy in continuous regime to a direct triggering method of the time-resolved laser absorption spectroscopy (TR-LAS) is presented. The main advantage of the developed method is its capability to measure the time evolution of the whole absorption profile with a preset time resolution, which can be less than 1 µs. Therefore, the presented method of repetitive sampling applied on LAS in plasma processes is capable of simultaneous measurement of the density and kinetic temperature of selected particles. Its appropriate applications are to periodical processes in technological plasma, namely pulsed plasma discharges. The developed method of TR-LAS was applied to measurements of the temporal evolution of density and kinetic temperature of argon metastable species during high-power impulse magnetron sputtering of titanium and titanium dioxide thin films.

Photocatalytic esterification under Mitsunobu reaction conditions mediated by flavin and visible light.

The usefulness of flavin-based aerial photooxidation in esterification under Mitsunobu reaction conditions was demonstrated, providing aerial dialkyl azodicarboxylate recycling/generation from the corresponding dialkyl hydrazine dicarboxylate. Simultaneously, activation of triphenylphosphine (Ph3P) by photoinduced electron transfer from flavin allows azo-reagent-free esterification. An optimized system with 3-methylriboflavin tetraacetate (10%), oxygen (terminal oxidant), visible light (450 nm), Ph3P, and dialkyl hydrazine dicarboxylate (10%) has been shown to provide efficient and stereoselective coupling of various alcohols and acids to esters with retention of configuration.

High magnetic field test of bismuth Hall sensors for ITER steady state magnetic diagnostic.

Performance of bismuth Hall sensors developed for the ITER steady state magnetic diagnostic was investigated for high magnetic fields in the range ±7 T. Response of the sensors to the magnetic field was found to be nonlinear particularly within the range ±1 T. Significant contribution of the planar Hall effect to the sensors output voltage causing undesirable cross field sensitivity was identified. It was demonstrated that this effect can be minimized by the optimization of the sensor geometry and alignment with the magnetic field and by the application of "current-spinning technique."

Decay Rate of Correlated Real-Space Delocalization Measures: Insights into Chemical Bonding and Mott Transitions from Hydrogen Chains.

We study in this contribution the spatial decay rate of real-space localization and delocalization indices in correlated systems. To that end, we examine Hubbard and quantum chemical models of simple cyclic hydrogen chains, showing that all descriptors of delocalization converge quickly toward the infinite chain limits. It is then shown that the localization index may be understood as a generalization of the standard order parameter in Mott insulator transitions and that the origin of the enigmatic sigmoidal profile of delocalization indices in chemical bond-breaking processes lies in the nonlinear mapping between intersite distances and correlation parameters. Although the long-range asymptotic decay of delocalization indices is exponential, we show that as the correlation parameter decreases quantum mechanical interference sets in and a switch to an oscillating pattern, related to core chemical concepts such as resonance or mesomerism, appears.

Tuning the Electronic Properties of the Dative N-B Bond with Associated O-B Interaction: Electron Localizability Indicator from X-Ray Wavefunction Refinement.

Despite the immense growth in interest in difluoroborate dyes, the nature of the interactions of the boron atom within the N-BF2 -O kernel is not yet fully understood. Herein, a set of real-space bonding indicators is used to quantify the electronic characteristics of the dative N-B bond in difluoroborate derivatives. The atoms-in-molecules (AIM) partitioning scheme is complemented by the electron localizability indicator (ELI-D) approach, and both were applied to experimental and theoretical electron-density distributions (X-ray constrained wavefunction fitting vs. DFT calculations). Additionally, Fermi orbital analysis was introduced for small DFT models to support and extend the findings for structures that contain BF2 .

EuTM(2)Ga(8) (TM = Co, Rh, Ir) - a contribution to the chemistry of the CeFe(2)Al(8)-type compounds.

The isostructural compounds EuTM(2)Ga(8) (TM = Co, Rh, Ir) were prepared by direct reaction of the elements by high-frequency thermal treatment. All three phases are isotypic with CeFe(2)Al(8) (space group Pbam, Pearson symbol oP44, Z = 4). The crystal structure was established from single-crystal X-ray diffraction data: a = 12.4322(7) A, b = 14.3814(9) A, and c = 4.0378(2) A for EuCo(2)Ga(8); a = 12.6001(6) A, b = 14.6757(7) A, and c = 4.1172(2) A for EuRh(2)Ga(8); and a = 12.6237(7) A, b = 14.6978(8) A, and c = 4.1486(2) A for EuIr(2)Ga(8), respectively. Analysis of the chemical bonding in EuRh(2)Ga(8) with the electron localizability tools reveals formation of the 3D [Rh(2)Ga(8)] polyanion build by polar covalent bonds. Europium interacts in two ways with the polyanion: mainly as a cation by charge transfer and additionally covalently by means of the electrons of the inner shells. Magnetic susceptibility measurements show Curie-Weiss paramagnetic behavior above 40 K with effective magnetic moments of 7.81, 8.05, and 8.27 micro(B)/f.u. for EuTM(2)Ga(8) (TM = Co, Rh, Ir). Antiferromagnetic ordering of Eu moments is observed in all three compounds below 20 K. Independently on the chemical composition of the coordination sphere, magnetic behavior and, especially, X-ray absorption spectra indicate predominantly the 4f(7) electronic configuration of europium with small admixture of the 4f(6) state.

Electron localizability for hexagonal element structures.

For 21 elements crystallizing in hexagonal structure density functional calculations were performed. The topology of the electron localizability indicator (ELI) allows classifying the elements as appertaining to one of six patterns. The bifurcation diagrams as well as the electron populations in ELI basins for each pattern are discussed.

Electron localization function in full-potential representation for crystalline materials.

The electron localization function (ELF) is implemented in the first-principles, all-electron, full-potential local orbital method. This full-potential implementation increases the accuracy with which the ELF can be computed for crystalline materials. Some representative results obtained are presented and compared with the results of other methods. Although for crystal structures with directed bonding only minor differences are found, in simple elemental metals, there are differences in the valence region, which give rise to different ELF topologies.

Features of the electron density in magnesium diboride: reconstruction from X-ray diffraction data and comparison with TB-LMTO and FPLO calculations.

Features of the electron density in MgB(2) reconstructed from room-temperature single-crystal X-ray diffraction intensities using a multipole model are considered. Topological analysis of the total electron density has been applied to characterize the atomic interactions in magnesium diboride. The shared-type B-B interaction in the B-atom layer reveals that both sigma and pi components of the bonding are strong. A closed-shell-type weak B-B pi interaction along the c axis of the unit cell has also been found. The Mg-B closed-shell interaction exhibits a bond path that is significantly curved towards the vertical Mg-atom chain ([110] direction). The latter two facts reflect two sorts of bonding interactions along the [001] direction. Integration of the electron density over the zero-flux atomic basins reveals a charge transfer of approximately 1.4 (1) electrons from the Mg atoms to the B-atom network. The calculated electric-field gradients at nuclear positions are in good agreement with experimental NMR values. The anharmonic displacement of the B atoms is also discussed. Calculations of the electron density by tight-binding linear muffin-tin orbital (TB-LMTO) and full-potential non-orthogonal local orbital (FPLO) methods confirm the results of the reconstruction from X-ray diffraction; for example, a charge transfer of 1.5 and 1.6 electrons, respectively, was found.

Prospective anthropometric analysis of sagittal orbital-globe relationship following fronto-orbital advancement in childhood.

Fronto-orbital advancement is a common procedure for correction of supraorbital retrusion in patients with coronal craniosynostosis. The aim of this study was two-fold: to quantitate change in the sagittal orbital-globe relationship following fronto-orbital advancement in childhood and to determine the ratio of skeletal-to-soft tissue movement. Soft-tissue points on the orbital rim, orbitale superius (os), orbitale laterale (ol), orbitale inferius (oi), and nasion (n), referenced to apex corneae (ac), were measured preoperatively and postoperatively by a custom-made anthropometer. Intraoperative bony advancement was measured with a caliper. Patients were selected with uniform advancement at the fronto-nasal suture and laterally at the mortise and tenon. Fifteen patients with syndromic craniosynostosis were included in the study (six male, nine female): Apert (n = 2), Crouzon (n = 5), Pfeiffer (n = 4), Saethre-Chotzen (n = 3), and Boston type (n = 1). Average age at operation was 8.7 years (range, 4.5 to 10.5 years). Age, sex, method of fixation, postoperative interval, diagnosis, and skeletal movement were analyzed for possible effect on the magnitude of soft-tissue advancement. Average intraoperative skeletal advancement was 12.1 mm, and average postoperative soft-tissue movement was 10.3 mm (p < 0.001), measured at the midpoint of the supraorbital rims (os). The soft tissue: skeletal movement ratio was 0.9:1. Os was the only point at which soft-tissue advancement could be predicted (Spearman's rank correlation coefficient = 0.67); soft-tissue changes at ol, oi, and n were unpredictable. Skeletal movement was the only determinant of soft-tissue advancement of all variables tested, i.e., diagnosis, age, sex, previous fronto-orbital advancement, and wire versus plate fixation. We make recommendations for calculating the magnitude of fronto-orbital advancement, based on preoperative anthropometry and a soft-to-hard tissue advancement factor.

Photogrammetric comparison of two methods for synchronous repair of bilateral cleft lip and nasal deformity.

The principle of synchronous repair of bilateral complete cleft lip and nasal deformity is established, and the techniques are evolving. We undertook photogrammetric comparison of the method described by Mulliken (group I, n = 15) and that described by Trott (group II, n = 10). Facial proportions and angles were measured on preoperative and postoperative photographs using defined anthropometric points. The following criteria were quantified for each test group: nasolabial angle, nasal tip angle and projection, nasal width, columellar length and width, and philtral width. All parameters in both groups were compared against each other and against normal age-matched values. Results were analyzed by t test. The nasolabial angle, nasal tip angle, and nasal width were abnormally wide for both techniques (p < 0.01 for both), and there was no difference between them. Nasal tip projection was greater than normal in both techniques (p < 0.01); group I had significantly greater projection than group II (p = 0.02). Columellar length as a proportion of nasal tip protrusion approached normal in group I but was significantly shorter than normal in group II (p < 0.001). Columellar width, as a proportion of nasal width, was normal for both groups. Philtral width, in proportion to nasal width, was normal in group I and abnormally high in group II (p < 0.001). This difference was significant between the two groups (p < 0.001). In a separate cohort of 10 group I patients, the nasolabial angle was measured on lateral photographs taken 1 year post-repair and at intervals to late childhood and adolescence. Nasolabial angle changed with age from obtuse to normal in 7 of 10 patients followed to 9 years of age and in 5 of 6 patients followed until age 15 years. Columellar and upper labial inclination to the vertical were measured in 7 of these patients at 3 to 4 years and again at 13 to 15 years. There was an increase in inclination of both columella and the upper lip, between the ages of 3 to 4 and 13 to 15 years, reflecting improved lip support and growth of septum and lateral cartilages.

Arteriovenous malformations of the head and neck: natural history and management.

This is a retrospective review of 81 patients with extracranial arteriovenous malformation of the head and neck who presented to the Vascular Anomalies Program in Boston over the last 20 years. This study focused on the natural history and effectiveness of treatment. The male to female ratio was 1:1.5. Arteriovenous malformations occur in anatomic patterns. Sixty-nine percent occurred in the midface, 14 percent in the upper third of the face, and 17 percent in the lower third. The most common sites were cheek (31 percent), ear (16 percent), nose (11 percent), and forehead (10 percent). A vascular anomaly was apparent at birth in 59 percent of patients (82 percent in men, 44 percent in women). Ten percent of patients noted onset in childhood, 10 percent in adolescence, and 21 percent in adulthood. Eight patients first noted the malformation at puberty, and six others experienced exacerbation during puberty. Fifteen women noted appearance or expansion of the malformation during pregnancy. Bony involvement occurred in 22 patients, most commonly in the maxilla and mandible. In seven patients, the bone was the primary site; in 15 other patients, the bone was involved secondarily. Arteriovenous malformations were categorized according to Schobinger clinical staging: 27 percent in stage I (quiescence), 38 percent in stage II (expansion), and 38 percent in stage III (destruction). There was a single patient with stage IV malformation (decompensation). Stage I lesions remained stable for long periods. Expansion (stage II) was usually followed by pain, bleeding, and ulceration (stage III). Once present, these symptoms and signs inevitably progressed until the malformation was resected. Resection margins were best determined intraoperatively by the bleeding pattern of the incised tissue and by Doppler. Subtotal excision or proximal ligation frequently resulted in rapid progression of the arteriovenous malformation. The overall cure rate was 60 percent, defined as radiographic absence of arteriovenous malformation. Cure rate for small malformations was 69 percent with excision only and 62 percent for extensive malformations with combined embolization-resection. The cure rate was 75 percent for stage I, 67 percent for stage II, and 48 percent for stage III malformations. Outcome was not affected significantly by age at treatment, sex, Schobinger stage, or treatment method. Mean follow-up was 4.6 years.

New instrument for orbital anthropometry.

A new instrument for orbital anthropometry is described. It consists of the base for a slit-lamp upon which the patient's head rests and rulers mounted on three independently movable axes. The z-axis probe is used to measure sagittal relationship between the corneal apices and points on the orbital perimeter. The instrument was tested against a sliding caliper and its accuracy was found to be within 0.2 mm or 2%. Intra- and inter-observer reliability were assessed by repeated measurements of two subjects by three observers. The intra-observer reliability was 0.99. Variations between observers was not significantly different for points orbitale inferius (oi), nasion (n), and orbitale superius (os), however, there was a statistically significant difference for measurement of orbitale laterale (ol). The correlation between anthropometric readings for lateral orbital wall to apex corneal (ol-ac) and CT scans for the same landmarks was assessed. Analysis of variance showed no difference between the measurement methods. This anthropometer is convenient and accurate for measurement of the sagittal orbital-globe relationships. A disadvantage is that it cannot be used intraoperatively.

Cool perfusion solutions for skin flaps: a new mixture of pharmacological agents which improves skin flap viability.

This study tested the hypotheses that perfusion of cooled skin flaps with established organ preservation solutions improves their viability and that this improvement can be further enhanced by pharmacological manipulation. Rabbit epigastric skin flaps were perfused with different solutions before explantation and stored at 8 degrees C for 6 days. In the first part of the experiment, flap viability was assessed 7 days after reperfusion of the flap via microvascular anastomoses. The different solutions were heparinised blood, University of Wisconsin solution, two of its modifications, EuroCollins solution and a pharmacological mixture containing phosphoenolpyruvate, desferrioxamine, nitrendipine, dextran 70 and a platelet-aggregating factor receptor antagonist (WEB 2170). In the second part, biochemical parameters of skin were measured at various reperfusion times. Adenosine triphosphate (ATP), reduced glutathione (GSH), myeloperoxidase (MPO) and tissue water were assayed at 0, 1, and 24 h after reperfusion. In addition, plasma thromboxane (TXB2) was measured at 0, 30 and 60 minutes after reperfusion. The viability of flaps perfused with the mixture (81%) was significantly higher than that of any of the other groups (39% for controls, 38% for EuroCollins, 13% for UW solution, 27% and 31% for its modifications). ATP levels after reperfusion were higher in the mixture group than in UW-perfused group. GSH levels in the mixture group were also higher than in the UW group, indicating higher level of protection against oxidative stress during reperfusion. There were no differences in MPO levels. Thromboxane levels associated with UW-perfused flaps were significantly higher than those associated with any other perfusion solution. In conclusion, perfusion of a mixture of pharmacological agents targeting specific aspects of ischaemia/reperfusion injury improved the viability of skin flaps stored in the cold for 6 days, whereas standard organ preservation solutions failed to affect significantly skin flap survival.