Elastic scattering of α-particles on10B forEα = 5?50 MeV

Experimental data of the elastic scattering of-particles on¹⁰B forE = 30–50.6 MeV are presented. They are analysed together with the data of a previous measurement forE = 5–30 MeV in the frame of the optical model including spin-orbit coupling. The interaction radii of the-¹⁰B-systems are determined with the Inopin-Ericson model forE = 5–50 MeV. The mean free path of-particles in¹⁰B is calculated.     

Decoding ‘Maximum Entropy’ Deconvolution

For over five decades, the mathematical procedure termed “maximum entropy” (M-E) has been used to deconvolve structure in spectra, optical and otherwise, although quantitative measures of performance remain unknown. Here, we examine this procedure analytically for the lowest two orders for a Lorentzian feature, obtaining expressions for the amount of sharpening and identifying how spurious structures appear. Illustrative examples are provided. These results enhance the utility of this widely used deconvolution approach to spectral analysis.     

Guessing PINs,One Partial PIN at a Time

Entering digits of a personal identification number (PIN) is a common form of authentication. One variant of this scheme is to request the digits from a random subset of positions, which is sometimes called a partial PIN. In this paper we consider strategies for guessing the PIN when a partial PIN scheme is in use, which allows the quantification of the strength of this mechanism. We suggest several strategies for guessing the PIN under the assumption that the organisation assigns PINs randomly and requests random positions from the PIN at each login. We present analytic and simulation results from the different strategies and explore their performance when guessing different sizes of PIN and requested subset. We find that the most effective strategies have a reasonable chance of recovering a PIN in tens to hundreds of guesses.     

Screen Printable Sol-Gel Materials for High-Throughput Borosilicate Glass Film Production

The use of sol-gel materials can simplify the industrial fabrication of high-efficiency silicon solar cells if a suitable deposition method is established. In this work, we investigate the possibilities to adapt a borosilicate glass sol-gel to provide a stable screen printing process. This material has previously been used as a boron dopant source for silicon solar cells. We now use an adjusted synthesis process, with an increased gelling time and different additives. This changes the rheological properties (i.e., the elastic and viscous moduli G′ and G″) in a way that avoids the dripping of paste through the screen and that stabilizes the material transfer in subsequent printing steps. Using this synthesis process, we were able to show a printing process with long-term stability of more than 500 prints. When comparing the adjusted to the initial paste, we show that, after thermal treatment, the obtained thin films are very similar in terms of their constitution, with a refractive index between n = 1.47 (initial) and n = 1.55 (adjusted). We also show that they provide the same amount of doping under the tested conditions (950 °C, 30 min), resulting in sheet resistances of R_□ = (42.5 ± 2.6) Ω/□ (initial) and R_□ = (46.4 ± 3.6) Ω/□ (adjusted).     

Guanidinates as Alternative Ligands for Organometallic Complexes

For decades, ligands such as phosphanes or cyclopentadienyl ring derivatives have dominated Coordination and Organometallic Chemistry. At the same time, alternative compounds have emerged that could compete either for a more practical and accessible synthesis or for greater control of steric and electronic properties. Guanidines, nitrogen-rich compounds, appear as one such potential alternatives as ligands or proligands. In addition to occurring in a plethora of natural compounds, and thus in compounds of pharmacological use, guanidines allow a wide variety of coordination modes to different metal centers along the periodic table, with their monoanionic chelate derivatives being the most common. In this review, we focused on the organometallic chemistry of guanidinato compounds, discussing selected examples of coordination modes, reactivity and uses in catalysis or materials science. We believe that these amazing ligands offer a new promise in Organometallic Chemistry.     

Comparison of Two Bovine Commercial Xenografts in the Regeneration of Critical Cranial Defects

Autologous bone is the gold standard in regeneration processes. However, there is an endless search for alternative materials in bone regeneration. Xenografts can act as bone substitutes given the difficulty of obtaining bone tissue from patients and before the limitations in the availability of homologous tissue donors. Bone neoformation was studied in critical-size defects created in the parietal bone of 40 adult male Wistar rats, implanted with xenografts composed of particulate bovine hydroxyapatite (HA) and with blocks of bovine hydroxyapatite (HA) and Collagen, which introduces crystallinity to the materials. The Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated the carbonate and phosphate groups of the hydroxyapatite and the amide groups of the collagen structure, while the thermal transitions for HA and HA/collagen composites established mainly dehydration endothermal processes, which increased (from 79 °C to 83 °C) for F2 due to the collagen presence. The xenograft’s X-ray powder diffraction (XRD) analysis also revealed the bovine HA crystalline structure, with a prominent peak centered at 32°. We observed macroporosity and mesoporosity in the xenografts from the morphology studies with heterogeneous distribution. The two xenografts induced neoformation in defects of critical size. Histological, histochemical, and scanning electron microscopy (SEM) analyses were performed 30, 60, and 90 days after implantation. The empty defects showed signs of neoformation lower than 30% in the three periods, while the defects implanted with the material showed partial regeneration. InterOss Collagen material temporarily induced osteon formation during the healing process. The results presented here are promising for bone regeneration, demonstrating a beneficial impact in the biomedical field.     

Dephasing Processes in the Molecular Dye Lumogen-F Orange Characterized by Two-Dimensional Electronic Spectroscopy

Molecular dyes are finding more and more applications in photonics and quantum technologies, such as polaritonic optical microcavities, organic quantum batteries and single-photon emitters for quantum sensing and metrology. For all these applications, it is of crucial importance to characterize the dephasing mechanisms. In this work we use two-dimensional electronic spectroscopy (2DES) to study the temperature dependent dephasing processes in the prototypical organic dye Lumogen-F orange. We model the 2DES maps using the Bloch equations for a two-level system and obtain a dephasing time T₂ = 53 fs at room temperature, which increases to T₂ = 94 fs at 86 K. Furthermore, spectral diffusion processes are observed and modeled by a combination of underdamped and overdamped Brownian oscillators. Our results provide useful design parameters for advanced optoelectronic and photonic devices incorporating dye molecules.     

Radiochemical Feasibility of Mixing of 99mTc-MAA and 90Y-Microspheres with Omnipaque Contrast

Yttrium-90 (⁹⁰Y) microspheres are widely used for the treatment of liver-dominant malignant tumors. They are infused via catheter into the hepatic artery branches supplying the tumor under fluoroscopic guidance based on pre-therapy angiography and Technetium-99m macroaggregated albumin (^99mTc-MAA) planning. However, at present, these microspheres are suspended in radiolucent media such as dextrose 5% (D5) solution. In order to monitor the real-time implantation of the microspheres into the tumor, the ⁹⁰Y microspheres could be suspended in omnipaque contrast for allowing visualization of the correct distribution of the microspheres into the tumor. The radiochemical purity of mixing ⁹⁰Y-microspheres in various concentrations of omnipaque was investigated. The radiochemical purity and feasibility of mixing ^99mTc-MAA with various concentrations of a standard contrast agent were also investigated. Results showed the radiochemical feasibility of mixing ⁹⁰Y-microspheres with omnipaque is radiochemically acceptable for allowing real-time visualization of radioembolization under fluoroscopy.     

Grafting of Anionic Decahydro-Closo-Decaborate Clusters on Keggin and Dawson-Type Polyoxometalates: Syntheses,Studies in Solution,DFT Calculations and Electrochemical Properties

Herein we report the synthesis of a new class of compounds associating Keggin and Dawson-type Polyoxometalates (POMs) with a derivative of the anionic decahydro-closo-decaborate cluster [B₁₀H₁₀]²⁻ through aminopropylsilyl ligand (APTES) acting as both a linker and a spacer between the two negatively charged species. Three new adducts were isolated and fully characterized by various NMR techniques and MALDI-TOF mass spectrometry, notably revealing the isolation of an unprecedented monofunctionalized SiW₁₀ derivative stabilized through intramolecular H-H dihydrogen contacts. DFT as well as electrochemical studies allowed studying the electronic effect of grafting the decaborate cluster on the POM moiety and its consequences on the hydrogen evolution reaction (HER) properties.     

Nano-Encapsulated Essential Oils as a Preservation Strategy for Meat and Meat Products Storage

Consumers today demand the use of natural additives and preservatives in all fresh and processed foods, including meat and meat products. Meat, however, is highly susceptible to oxidation and microbial growth that cause rapid spoilage. Essential oils are natural preservatives used in meat and meat products. While they provide antioxidant and antimicrobial properties, they also present certain disadvantages, as their intense flavor can affect the sensory properties of meat, they are subject to degradation under certain environmental conditions, and have low solubility in water. Different methods of incorporation have been tested to address these issues. Solutions suggested to date include nanotechnological processes in which essential oils are encapsulated into a lipid or biopolymer matrix that reduces the required dose and allows the formation of modified release systems. This review focuses on recent studies on applications of nano-encapsulated essential oils as sources of natural preservation systems that prevent meat spoilage. The studies are critically analyzed considering their effectiveness in the nanostructuring of essential oils and improvements in the quality of meat and meat products by focusing on the control of oxidation reactions and microbial growth to increase food safety and ensure innocuity.