RESUMEN
The reversible modulation of fluorescence signals by light is of high interest for applications in super-resolution microscopy, especially on the DNA level. In this article we describe the systematic variation of the core structure in nucleoside-based diarylethenes (DAEs), in order to generate intrinsically fluorescent photochromes. The introduction of aromatic bridging units resulted in a bathochromic shift of the visible absorption maximum of the closed-ring form, but caused reduced thermal stability and switching efficiency. The replacement of the thiophene aryl unit by thiazol improved the thermal stability, whereas the introduction of a benzothiophene unit led to inherent and modulatable turn-off fluorescence. This feature was further optimized by introducing a fluorescent indole nucleobase into the DAE core, resulting in an effective photoswitch with a fluorescence quantum yield of 0.0166 and a fluorescence turn-off factor of 3.2. The site-specific incorporation into an oligonucleotide resulted in fluorescence-switchable DNA with high cyclization quantum yields and switching efficiency, which may facilitate future applications.
Asunto(s)
Nucleósidos , Oligonucleótidos , Etilenos , Fluorescencia , Procesos FotoquímicosRESUMEN
A transition metal-free formal synthesis of phenoxazine is presented. The key step of the sequence is a high-yielding O-arylation of a phenol with an unsymmetrical diaryliodonium salt to provide an ortho-disubstituted diaryl ether. This species was cyclized to acetylphenoxazine in moderate yield. The overall yield in the three-step sequence is 72% based on recovered diaryl ether. An interesting, unusually stable iodine(III) intermediate in the O-arylation was observed by NMR and could be converted to the product upon longer reaction time.
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The enantioselective rhodium-catalyzed cyclization of 2-allenylbenzoxazoles to the corresponding vinyl-functionalized, fused heterocyclic structures is reported. The presented method offers several advantages, including the use of low catalyst loadings, commercially available catalyst precursors, and mild reaction conditions. Due to its broad scope, scalability, and valuable products, we consider this methodology to be a useful tool for the construction of benzoxazole-containing building blocks.
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Background: Integrating music into pain treatment demonstrates significant benefits, effectively reducing subjective pain levels and perioperative opioid requirements. Currently, the relationship between the impact of specific types of music and listeners' socio-cultural background is still unclear. This is especially relevant given that sociological research indicates that these factors can have a notable influence on music preference and perception. Current evidence suggests that individuals who choose their own music may experience greater benefits. However, additional research is needed to comprehensively grasp whether the effect of (preferred) music on pain endurance remains consistent across different socio-cultural backgrounds. Methods: In this study, a collaborative effort between medical and sociological researchers aims to investigate music-induced analgesia differentiated by socio-cultural background in healthy volunteers. Participants (n = 84) will listen to self-, and researcher-chosen music and a podcast as a control condition in a cross-over study design. The primary outcome of this study is pain endurance measured by electric stimuli of increasing intensity. Detailed sociological validated questionnaires will be utilized. Considering the notable influence of educational level on music taste formation found in previous research and its crucial role as a source of socio-cultural differentiation, participants will be stratified based on their level of education. Discussion: This experimental study represents one of the first efforts to gain a socio-culturally differentiated understanding of the therapeutic potential of music. Consequently, this could pave the way to purposefully and inclusively implement personalized music in healthcare settings.
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Herein, we report a highly enantio- and diastereoselective rhodium-catalyzed cyclization of N-allenyltryptamines and 3-allenylindoles to 6-membered spirocyclic indolenines. This allylic addition methodology offers the advantage of using a comparably cheap commercially available ligand with low loadings of an affordable rhodium precursor. The products can be converted into functionalized spirooxindoles and spiroindolines, which are regarded as important building blocks for the synthesis of a lot of natural products with biological activities.
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The treatments of avascular osteonecrosis (AVN) include both conservative and surgical methods which are dependent on the stage and progression of the disease. The vasoactive-prostaglandin-analogue iloprost (PGI2) has been utilized in several areas of medicine and recently has been used for the treatment of AVN. A total of 108 patients with 136 osteonecrosis of different joints, etiology and severity were treated with iloprost. The mean follow-up was 49.71 months: range 15-96 months, and outcome measurements recorded regarding subjective complaints, visual analog scale (pain), function and survival. The outcome scores used include the Harris Hip Score, Knee Society score, Foot and Ankle Survey, visual analogue scale (VAS) and a separate questionnaire. The location and etiology of AVN in our study demonstrated the typical pattern. All of the observed side effects of the therapy were minor and completely reversible. Most of patients (74.8%) showed a significant improvement of subjective complaints and decrease in VAS pain scores after the treatment with iloprost. However, 20% of the treated joints with the stadium Association for Research on Osseous Circulation (ARCO) grade 2, 71% with ARCO 3 and 100% with ARCO 4 underwent subsequent total joint replacement. The medical treatment of bone marrow edema or avascular osteonecrosis by Iloprost provides an safe and effective alternative strategy in the management of AVN presenting in the early stages (ARCO 1 or 2). For more advanced stages (ARCO 3 or 4), surgical intervention should be prioritized.