‘Soft’ phonon modes,structured diffuse scattering and the crystal chemistry of Fe-bearing sphalerites

Electron diffraction has been used to carefully investigate the reciprocal lattices of a range of iron-bearing sphalerites looking for evidence of Fe clustering and/or Fe/Zn ordering in the form of either additional satellite reflections or a structured diffuse intensity distribution accompanying the strong Bragg reflections of the underlying sphalerite-type average structure. While a highly structured diffuse intensity distribution in the form of transverse polarized f110g sheets of diffuse intensity has been detected and found to be characteristic of all compositions,it does not appear to arise from Fe clustering and/or Fe/Zn ordering. Rather inherently low frequency,and therefore strongly thermally excited,phonon modes propagating along reciprocal space directions perpendicular to each of the six /110S real space directions of the average structure are suggested to be responsible for these f110g sheets of diffuse intensity. Monte Carlo simulation (for a range of Zn–S,Zn–Zn and S–S interaction strengths) and subsequent Fourier transformation is used to confirm the existence of these low-frequency phonon modes of distortion as well as to show that they are an intrinsic,predictable property of the corner-connected tetrahedral structure of sphalerite. The low-frequency phonon modes involve coupled (Zn,Fe) and S motion in one-dimensional strings along /110S real space directions

Composition-induced structural phase transitions in the (Ba1xLax)2In2O5+x (0pxp0.6) system

Composition-induced structural phase changes across the high temperature, fast oxide ion conducting (Ba1xLax)2In2O5+x, 0pxp0.6, system have been carefully analysed using hard mode infrared (IR) powder absorption spectroscopy, X-ray powder diffraction and electron diffraction. An orthorhombic brownmillerite to three-dimensionally disordered cubic perovskite phase transition in this system is signalled by a drastic change in slope of both wavenumber and average line widths of IR spectra as a function of composition. Some evidence is found for the existence of an intermediate tetragonal phase (previously reported to exist from electron diffraction data) around x 0:2: The new spectroscopic data have been used to compare microscopic and macroscopic strain parameters arising from variation in composition. The strain and spectroscopic data are consistent with firstorder character for the tetragonal-orthorhombic transition, while the cubic-tetragonal transition could be continuous. Differences between the variation with composition of spectral parameters and of macroscopic strain parameters are consistent with a substantial order/disorder component for the transitions. There is also evidence for precursor effects within the cubic structure before symmetry is broken

Metastable anions of dinitrobenzene: resonances for electron attachment and kinetic energy release

Attachment of free, low-energy electrons to dinitrobenzene (DNB) in the gas phase leads to DNB as well as several fragment anions. DNB, (DNB-H), (DNB-NO), (DNB-2NO), and (DNB-NO(2)) are found to undergo metastable (unimolecular) dissociation. A rich pattern of resonances in the yield of these metastable reactions versus electron energy is observed; some resonances are highly isomer-specific. Most metastable reactions are accompanied by large average kinetic energy releases (KER) that range from 0.5 to 1.32 eV, typical of complex rearrangement reactions, but (1,3-DNB-H)(-) features a resonance with a KER of only 0.06 eV for loss of NO. (1,3-DNB-NO)(-) offers a rare example of a sequential metastable reaction, namely, loss of NO followed by loss of CO to yield C(5)H(4)O(-) with a large KER of 1.32 eV. The G4(MP2) method is applied to compute adiabatic electron affinities and reaction energies for several of the observed metastable channels. (C) 2010 American Institute of Physics. [doi:10.1063/1.3514931

Artros - en sjukdom som drabbar både djur och människa, en komparativ studie med kaninen som modelldjur.

SAMMANFATTNING Artros och skador i ledbrosk är vanliga problem hos både människor och djur, som orsakar stora fysiska besvär i form av smärta och nedsatt rörelseförmåga. Idag finns ett flertal olika behandlingsmetoder mot artros, men ännu finns ingen bra behandlingsmetod för att åstadkomma läkning av ett skadat ledbrosk. I den här studien användes kanin som modelldjur för att utvärdera en ny behandling mot artros på människa. Målet var att stimulera nybildning av ledbrosk via rekrytering av mesenkymala stamceller. Studien utfördes på 20 kaniner av rasen New Zeeland White, 6-7 månader gamla honor med en kroppsvikt på ca 4 kg. En ledskada skapades med borr på den mediala femurkondylen i kaninernas vänstra knäled under anestesi. Därefter injicerades en hyaluronsyragel enbart eller tillsammans med tillväxtfaktorn bone morphogenic protein-2 (BMP-2) i leden. En likadan skada skapades i den högra knäleden, men i denna injicierades istället koksaltlösning som kontrollbehandling. De två första veckorna postoperativt undersöktes kaninerna dagligen avseende allmäntillstånd och vikt. Knälederna undersöktes särskilt efter tecken på infektion och graden av hälta uppskattades på en 4-gradig skala. Efter tre månader (n=5) och sex månader (n=10) avlivades kaninerna och knälederna undersöktes histologiskt samt med magnetkamera (MRI) för att utvärdera nybildning av ledbrosk. Studien utgör den kliniska delen av forskningsprojektet och i detta arbete presenteras resultaten från operationen och den postoperativa perioden.SUMMARY Osteoarthritis and articular cartilage lesions are common problems affecting both people and animals, causing large amounts of pain and functional disability. Many different strategies have been used to treat osteoarthritis, but no good treatment to accomplish regeneration of damaged articular cartilage is available today. In this study rabbits were used as a model for finding a new treatment against osteoarthritis in humans. The goal was to stimulate regeneration of damaged articular cartilage by recruitment of mesenchymal stem cells from subchondral bone. The study was performed on 20 New Zealand White rabbits. A cartilage defect was induced on the medial femoral condyle in the left knee joint. The defects were treated with hyaluronan hydrogel containing the growth factor bone morphogenic protein-2 (BMP-2) or hyaluronan hydrogel itself. The same defect was induced in the rabbits’ right knee joint which was injected with isotonic saline to serve as a control. The first weeks postoperatively the rabbits were examined every day. The knees were examined for signs of infection and the grade of lameness was estimated on a scale from 0 to 3. After surgery the animals were kept for three months (n=5) or six months (n=10) until they were euthanized. A pathological examination and a magnetic resonance imaging (MRI) of the knee joints were performed to evaluate the regeneration of articular cartilage. The study is a part of a larger research project and in this assignment the results from the clinical part are presented

Development and characterization of biodegradable biorenewable polymeric nanocomposites for food packaging applications

During the last 10 decades, plastic products have dominated humans’ lives with various applications in different fields, and particularly in food packaging industry. The fact that plastics do have numerous desirable characteristics does not conceal their detrimental effect on the environment and on human health. In order to overcome these problematic issues and to contribute to sustainable development in the future, other alternatives represented in employing biorenewable biodegradable polymers are implemented for plastics production. Poly (lactic acid) (PLA) is one of the most common employed biopolymer owing to its interesting characteristics. However, PLA exhibits poor mechanical and barrier properties. Natural plasticizers and nano-reinforcement are incorporated into PLA matrix in order to overcome its brittle nature and to improve its barrier properties, particularly for the purpose of food packaging applications. This research focused on two parts: (i) improving the toughness and flexibility of PLA by investigating the effect of addition of three different plasticizers, namely, polyethylene glycol (PEG), tri n-butyl citrate (TBC), and triacetin (TA) of different concentrations using cast solution method, and (ii) PLA/TA 10%, the best investigated combination among all in terms of mechanical properties, was then chosen as the base system to further investigate the effect of incorporating four different nano-reinforcements, namely, carbon nanotubes (CNT), COOH functionalized carbon nanotubes (CNTCOOH), graphene platelets (GNP), and COOH functionalized graphene nanoplatelets (GNPCOOH) of different concentrations for fabrication of PLA nanocomposites. The physical, chemical, and barrier properties of all prepared samples were investigated through the stress-relaxation measurements, DSC, TGA, Mercury Porosimetry, biodegradability, water absorption, oxygen permeability, and water vapour transmission. GNPCOOH nanocomposites exhibited the best mechanical behaviour among all samples, while TGA analysis revealed that it had no effect on the thermal stability. Results obtained by Hg porosimetry have shown that the total porosity has tremendously decreased by incorporation of the investigated nanofillers. The biodegradation of PLA nanocomposites in natural compost was investigated and it was observed that the incorporation of nanofillers had no specific effect on biodegradation of PLA nanocomposites. Water absorption test revealed that the functionalized nanofillers showed relative increase in water absorption as compared to pristine nanofillers. Oxygen permeability test showed that lower concentrations of GNPCOOH had higher oxygen diffusion, while higher concentrations revealed a remarkable decrease in oxygen permeability. Water vapour transmission test showed that the incorporation of nanofillers has considerably decreased the rate of water vapour transmission

Kemicentrum vid Lunds universitet : perspektiv på organisation och forskning vid Sveriges första storinstitution

Det är nu 40 år sedan Sveriges första storinstitution, Kemicentrum vid Lunds universitet, bildades 1967. Kemiämnena vid Lunds universitet, kemisektionen vid Lunds Tekniska Högskola och Alnarpsinstitutets mejeriforskning sammanfördes i ett gemensamt byggnadskomplex i norra Lund. Tidigare självständiga institutioner med lång historia och nybildade forskningsinriktningar vid LTH blev nu alla forskningsavdelningar vid en gemensam storinstitution. Denna bok ger en mångsidig beskrivning av Kemicentrum. Bland annat diskuteras vilka faktorer som kan förklara storinstitutionens tillkomst och omvandling över tid. Bokens huvudsakliga fokus ligger på Kemicentrums organisation och forskning

Boron Directed RegioselectivAromatic Ortho Functionalizations

Selectivity is crucial in modern organic synthesis, as it allows for precise molecular modifications while minimizing undesired side reactions. Controlling selectivity is essential for improving reaction yields, reducing purification steps, and enhancing overall synthetic efficiency. This is particularly important in synthetic methodologies, where precise control over regioselectivity is essential for constructing complex molecules efficiently and reliably. In this work, we have developed a series of selective deborylative transformations that leverage the unique reactivity of dibromoboracycles to achieve regioselective C–halogen, C– aryl, and C–benzyl bond formations in 2–aryl–N–heteroarenes, aldehydes, N–aryl amides and ureas. By integrating nitrogen and carbonyl-directed borylation with subsequent functionalization, we have introduced efficient, metal-free, and scalable methodologies that address long-standing challenges in site-selective C–H functionalization. Our oxidative halodeboronation strategy provides a direct and regioselective approach to ortho-halogenation, eliminating the need for transition-metal catalysts while ensuring high functional group tolerance. This protocol expands the synthetic utility of boron, enabling the precise installation of halogens in 2–aryl–N–heteroarenes and N–aryl amides under mild conditions. Furthermore, we have demonstrated that dibromoboracycles can be directly employed in ortho-arylation and ortho-benzylation, bypassing the conventional BBr₂-to-BPin conversion. This unique approach facilitates the efficient synthesis of biaryl amides, diarylmethane amides, and dibenzoazepines, unlocking new avenues for selective C(sp²)–C(sp²) and C(sp²)– C(sp³) bond formation. Additionally, our method enables one-pot diagonal diarylation, allowing streamlined access to complex molecular architectures such as tetraarylbenzenediamines and N–doped fulminenes. Finally, we introduce a scalable and chromatography-free synthesis of aryl-difluoroborane (Ar–BF₂) compounds, which exhibit enhanced stability and reactivity. These Ar–BF₂ species serve as highly versatile intermediates for late-stage functionalization, enabling diverse transformations, including radioiodination, halogenation, hydroxylation, azidation, and Suzuki-Miyaura cross-coupling. Their broad applicability highlights their potential as powerful tools in pharmaceutical synthesis and beyond. Overall, this work represents a significant advancement in boron-mediated functionalization, establishing a unified platform for regioselective C–H activation and cross-coupling reactions. By harnessing the intrinsic reactivity of dibromoboracycles, we provide highly selective, operationally simple, and scalable strategies that eliminate unnecessary synthetic steps, paving the way for future developments in boron-directed transformations and late-stage functionalization