Chronic Rupture of the Pectoralis Major: Current Concepts and Various Surgical Repair Techniques - A Mini Review.

Various surgical repair techniques, including autograft and allograft reconstructions, have been reported for the management of chronic pectoralis major ruptures, but outcome reporting remains highly heterogeneous. This narrative review aimed to provide a deeper understanding of these techniques, emphasizing the need for larger-scale prospective trials to support evidence-based recommendations for surgeons. We conducted a search of PubMed/Medline, Cochrane Library, Embase, and Google Scholar for English-language articles published between 1822 and 2023, using the following keywords: "chronic pectoralis major ruptures," "chronic pectoralis major tears," and "patient outcomes." Overall, more than 60 reported cases were retrieved, along with a few prospective studies and review articles. Based on the compiled literature, most pectoralis major tears tend to arise at the tendo-osseus junction. In the absence of contra-indications such as old age and multiple comorbidities, surgical intervention is considered the golden care standard. The most commonly performed repair techniques include suture anchor fixation, transosseous fixation (TOS), and cortical bone fixation. Among the three techniques, no significant differences in cyclic loading or load-to-failure properties of the constructs were recorded. In chronic cases, in which direct repair is not possible, various autograft and allograft reconstructions were described, with quite heterogeneous outcome reporting, rendering comparative analyses difficult. Currently, no single technique has been established as the gold standard for the treatment of chronic pectoralis major ruptures. The most commonly performed repair techniques include suture anchor fixation, TOS, and cortical bone fixation. In chronic cases where direct repair is not feasible, various autograft and allograft reconstructions are employed. There is a need for larger-scale prospective trials with standardized outcome reporting to develop evidence-based recommendations, providing surgeons with safe and effective guidelines for treatment

Superparamagnetic properties of hemozoin

We report that hemozoin nanocrystals demonstrate superparamagnetic properties, with direct measurements of the synthetic hemozoin magnetization. The results show that the magnetic permeability constant varies from mu = 4585 (at -20 degrees C) to 3843 (+20 degrees C), with the values corresponding to a superparamagnetic system. Similar results were obtained from the analysis of the diffusion separation of natural hemozoin nanocrystals in the magnetic field gradient, with mu = 6783 exceeding the value obtained in direct measurements by the factor of 1.8. This difference is interpreted in terms of structural differences between the synthetic and natural hemozoin. The ab initio analysis of the hemozoin elementary cell showed that the Fe3+ ion is in the high-spin state (S = 5/2), while the exchange interaction between Fe3+ electron-spin states was much stronger than k(B)T at room temperature. Thus, the spin dynamics of the neighboring Fe3+ ions are strongly correlated, lending support to the superparamagnetism

Refraction law and Fermat principle: a project using the ant colony optimization algorithm for undergraduate students in physics

info:eu-repo/semantics/publishe

NMR Transversal Relaxivity of Suspensions of Lanthanide Oxide Nanoparticles

Aqueous suspensions of paramagnetic lanthanide oxide nanoparticles have been studied by NMR relaxometry. The observed relaxivities are explained by the static dephasing regime (SDR) theory. The corresponding R2 relaxivities are considerably smaller and are strongly dependent on the interval between the two refocusing pulses. The experimental data are rationalized by assuming the value of the diffusion correlation time, τD, to be very long in a layer with adsorbed xanthan on the particle's surface. In this layer, the refocusing pulses are fully effective and R2 ≈ 0. Outside this layer, the diffusion model for weakly magnetized particles was applied. From the fit of the experimental relaxation data with this model, both the particle radii (rp) and the radii of the spheres, within which the refocusing pulses are fully effective (rdiff), were estimated. The values of rp obtained are in agreement with those determined by dynamic light scattering. Because the value of rdiff depends on the external magnetic field B and on the magnetic moment of the lanthanide of interest (μeff2), the R2 relaxivity was found to be proportional to B and to μeff2

Electron Paramagnetic Resonance Imaging of Melanin in Honey Bee.

Honey bees play a crucial role in the nature by pollinating wild flowers. Over the past years, there has been an increasing concern regarding the honey bee colony decline. Pesticides or environmental effects targeting the biochemistry of insect chitin and cuticle coating may be in part responsible for honey bee pathologies. We here propose the use of electron paramagnetic resonance imaging (EPRI) as a tool to image the melanin-chitin complexes as part of the exoskeleton of the honey bee. EPRI at 9.65 GHz was applied on intact freeze-dried bees. The imaging data were collected on the melanin peak. High-resolution images revealed that this compound is extensively distributed in the periphery of the animal, data consistent with the localization in the cuticle of the bee. While EPR of melanin has been so far explored in the context of melanoma characterization, it may offer new opportunities in research on honey bees and other insects