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Raman spectroscopy has been used to measure the concentration of a pharmaceutically relevant model amine intermediate for positive allosteric modulators of nicotinic acetylcholine receptor in a ω-transaminase-catalyzed conversion. A model based on a one-dimensional convolutional neural network was developed to translate raw data augmented Raman spectra directly into substrate concentrations, with which the conversion from ketone to amine by ω-transaminase could be determined over time. The model showed very good predictive capabilities, with R 2 values higher than 0.99 for the spectra included in the modeling and 0.964 for an independent dataset. However, the model could not extrapolate outside the concentrations specified by the model. The presented work shows the potential of Raman spectroscopy as a real-time monitoring tool for biocatalytic reactions., (© 2024 The Authors. Biotechnology Progress published by Wiley Periodicals LLC on behalf of American Institute of Chemical Engineers.)

This study investigates the validity evidence of metrics used for the assessment of surgical skills for Manual Small Incision Cataract Surgery (MSICS) in a virtual reality simulator. MSICS surgery is a low-cost, low-technology cataract surgery technique, which is widely used in low- and middle-income countries. However, there is a lack of cataract surgeons globally, and efficient and evidence-based training of new surgeons is needed. In order to investigate the validity of simulator metrics, we included three groups of participants: (1) MSICS novices who were ophthalmologists with no cataract surgery experience, (2) MSICS novices who were experienced phacoemulsification cataract surgeons, but with no MSICS experience, and (3) experienced phacoemulsification and MSICS surgeons. The evaluation included 11 steps of the MSICS procedure, and all simulator metrics for those steps were reviewed. Of the 55 initial metrics, 30 showed high positive discriminative ability. A test passing score of 20 out of 30 was established, and one of 15 novices with no MSICS experience (mean score 15.5) and 7 out of 10 experienced MSICS surgeons (mean score 22.7) passed the test. We have developed and established validity evidence for a test for MSICS skills in a virtual reality simulator for future use in proficiency-based training and evidence-based testing of training interventions., (© 2023. The Author(s).)

Purpose: To evaluate the relationship between patient outcome and surgical experience by developing an objective quality measure of macular hole surgery based on forceps damage to the inner retina., Methods: We retrospectively examined 3 macular hole case series >1 year after pars plana vitrectomy, internal limiting membrane peeling and gas tamponade. The patients were operated by (1) a novice surgeon (<20 cases), (2) an intermediate (150+ cases) and (3) an experienced surgeon (2000+ cases). Primary outcome was inner retinal volume defect as segmented from optical coherence tomography (GCL++: thickness from internal limiting membrane to inner plexiform layer). Secondary outcome was retinal function measured by confocal microperimetry using a custom scanning protocol., Results: Thirty-two patients were examined: 11, 10 and 11 patients in the novice, intermediate and experienced surgeon group, respectively. Median GCL++ volume defect was 23.68 × 10 6  μm 3 (IQR: 22.77 × 10 6 -44.81 × 10 6 μm 3 ), 8.42 × 10 6 μm 3 (IQR: 4.86 × 10 6 -10.03 × 10 6 μm 3 ) and 3.55 × 10 6 μm 3 (IQR: 1.44 × 10 3 -7.94 × 10 6 μm 3 ) in the novice, intermediate and experienced surgeon group, respectively (p = 0.0004). The novice surgeon volume defect differed significantly from the intermediate and experienced surgeon (p = 0.016 and p = 0.0002, respectively). A subset of 12 patients underwent microperimetry measurements demonstrating correlation between inner retinal volume defect and reduced retinal sensitivity (p = 0.02)., Conclusions: Forceps induced inner retinal damage commonly occurs during initiation of internal limiting membrane peeling in macular hole surgery. Damage to the structure and function of the inner retina seems to correlate to surgical experience., (© 2021 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: To investigate the learning curve of robot-assisted vitreoretinal surgery compared to manual surgery in a simulated setting., Methods: The study was designed as a randomized controlled longitudinal study. Eight ophthalmic trainees in the 1st or 2nd year of their specialization were included. The participants were randomized to either manual or robot-assisted surgery. Participants completed repetitions of a test consisting of three vitreoretinal modules on the Eyesi virtual reality simulator. The primary outcome measure was time to learning curve plateau (minutes) for total test score. The secondary outcome measures were instrument movement (mm), tissue treatment (mm 2 ) and time with instruments inserted (seconds)., Results: There was no significant difference in time to learning curve plateau for robot-assisted vitreoretinal surgery compared to manual. Robot-assisted vitreoretinal surgery was associated with less instrument movements (i.e. improved precision), -0.91 standard deviation (SD) units (p < 0.001). Furthermore, robot-assisted vitreoretinal surgery was associated with less tissue damage when compared to manual surgery, -0.94 SD units (p = 0.002). Lastly, robot-assisted vitreoretinal surgery was slower than manual surgery, 0.93 SD units (p < 0.001)., Conclusions: There was no significant difference between the lengths of the learning curves for robot-assisted vitreoretinal surgery compared to manual surgery. Robot-assisted vitreoretinal surgery was more precise, associated with less tissue damage, and slower., (© 2021 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: To investigate which patient-related outcomes are dependent on the experience of the cataract surgeon., Methods: The study was designed as a prospective observational study. Novice (<150 surgeries performed) and experienced (>1000 surgeries performed) cataract surgeons from the Department of Ophthalmology, Rigshospitalet - Glostrup and Nordsjaellands Hospital - Hillerød were included in the study. Patients operated by the included surgeons were examined preoperatively, 1 day, 3 days, and 3 weeks after standard, noncomplicated cataract surgery. Primary outcomes were change in central corneal thickness and endothelial cell loss. Secondary outcomes were best-corrected visual acuity, intraocular pressure, aqueous flare, central macular thickness, and surgical complications., Results: Surgery performed by novice surgeons resulted in significantly lower visual acuity (mean -3.6 letters (Early Treatment Diabetic Retinopathy Study (ETDRS)); 95% CI: -7.3; -0.4, p = 0.03) and greater corneal thickness (mean 26.7 µm; 95% CI: 6.8; 46.6, p = 0.01) on the first day postoperative than surgery performed by experienced surgeons., Conclusion: The experience of the cataract surgeon affected visual acuity and central corneal thickness in the immediate postoperative period. In the future, these patient-related outcomes may be used to assess the technical proficiency of surgical trainees and investigate the effect of different training programs., (© 2020 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: To investigate the correlation between performance on a virtual reality simulator and real-life cataract surgical performance., Setting: Nine ophthalmology departments in Denmark and Copenhagen Academy for Medical Education and Simulation, Copenhagen, Denmark., Design: Prospective multicenter study., Methods: Cataract surgeons with different experience levels were included. The participants performed 3 consecutive video-recorded phacoemulsification surgeries that were rated by masked raters using the Objective Structured Assessment of Cataract Surgical Skills (OSACSS) scoring system. Thereafter, the participants performed a previously validated test on an Eyesi virtual reality simulator. Primary outcomes were the mean OSACSS score from all 3 surgeries and the simulator score from the participants' first repetition of the performance test., Result: Nineteen surgeons participated. There was a statistically significant correlation between the simulator performance score and the mean OSACSS score across all experience levels, with a Pearson correlation of 0.65 (P = .003, R 2  = 0.42)., Conclusion: Simulator performance was significantly correlated with real-life cataract surgical performance., (Copyright © 2019 ASCRS and ESCRS. All rights reserved.)

Purpose: Craniopharyngioma often causes visual loss due to the close relation to the anterior visual pathways. This study investigates the incidence and predictors of visual outcomes in patients with craniopharyngioma., Methods: Data from sixty-six patients who underwent surgery for craniopharyngioma from 2009 to 2013 in Denmark were reviewed. Primary outcomes were visual acuity (VA) and visual field (VF) defects from pre-and postoperative visits. Secondary outcomes were optic nerve atrophy (OA) and papilledema., Results: Fifty-eight patients were included. The VA of the patients 1-year after surgery improved by -0.16 log(MAR) (95%CI: -0.30 to -0.02; p = 0.0266). Visual field (VF) defects worsened in 17 eyes (30%), remained stable in 21 eyes (37%) and improved in 19 eyes (33%). The presence of papilledema and the absence of OA were significantly correlated with an improvement in VA postoperatively (p = 0.011 and p = 0.011, respectively). Patients undergoing surgery within a week or less after their first ophthalmological examination had a significant improvement in VA (-0.36; 95%CI: -0.62 to -0.09; p = 0.0099). Patients undergoing surgery using a subfrontal approach also showed improvement in VA (p = 0.048). Tumour recurrence had a significantly worse VA outcome (p = 0.0074)., Conclusion: Patients show a slight improvement in VA 1-year after operation for craniopharyngioma. The presence of papilledema and early surgical intervention is associated with a significant improvement in VA. Early involvement of a dedicated ophthalmologist is recommended to secure an early detection of a visual decline and potential tumour recurrence., (© 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

A three-component coupling protocol has been developed for the generation of 3-oxo-3-(hetero)arylpropanenitriles via a carbonylative palladium-catalyzed α-arylation of tert-butyl 2-cyanoacetates with (hetero)aryl bromides followed by an acid-mediated decarboxylation step. Through the combination of only a stoichiometric loading of carbon monoxide and mild basic reaction conditions such as MgCl2 and dicyclohexylmethylamine for the deprotonation step, an excellent functional group tolerance was ensured for the methodology. Through the use of (13)C-labeled carbon monoxide generated from (13)COgen, the corresponding (13)C-isotopically labeled β-ketonitriles were obtained, and these products could subsequently be converted into cyanoalkynes and 3-cyanobenzofurans with site specific (13)C-isotope labeling.

From an interplay of high-resolution scanning tunneling microscopy (STM) imaging and density functional theory (DFT) calculations we demonstrate that by delicately choosing the parent molecule (adenine) we are able to tune the self-assembled nanostructures of adenine derivatives which are directed by the specific intermolecular interactions provided by the adenine moiety.

Supramolecular patterns formed by adsorption from a liquid of nucleobase-terminated molecular rods on a graphite surface were investigated by scanning tunneling microscopy.

DNA nanotechnology and particularly DNA origami, in which long, single-stranded DNA molecules are folded into predetermined shapes, can be used to form complex self-assembled nanostructures. Although DNA itself has limited chemical, optical or electronic functionality, DNA nanostructures can serve as templates for building materials with new functional properties. Relatively large nanocomponents such as nanoparticles and biomolecules can also be integrated into DNA nanostructures and imaged. Here, we show that chemical reactions with single molecules can be performed and imaged at a local position on a DNA origami scaffold by atomic force microscopy. The high yields and chemoselectivities of successive cleavage and bond-forming reactions observed in these experiments demonstrate the feasibility of post-assembly chemical modification of DNA nanostructures and their potential use as locally addressable solid supports.

Triplex DNA binders can effectively control copper-catalysed alkyne-azide click reactions in DNA architecture, such that either duplex or triplex DNA directed reactions of terminally attached azides and alkynes occur, in the absence or presence of triplex DNA binder, respectively.

Self-assembly at the liquid/solid interface of an electrochemically active DNA nucleobase analogue, 1H-benzoimidazole-4,7-dione (Q), has been studied by means of scanning tunneling microscopy (STM). High-resolution STM images revealed the formation of well-ordered two-dimensional (2D) supramolecular nanostructures when the Q molecules are adsorbed onto the graphite surface from a 1-octanol solution. Detailed analysis shows that the observed 2D nanostructures are mainly dominated by hydrogen-bonded Q molecules. Since Q can be considered as a molecule mimicking the nucleobase guanine (G), which is known to form Watson-Crick base pairs with its complementary nucleobase cytosine (C), we have examined the binding ability of Q with C realized by available hydrogen-bonding sites on both Q and C molecules. Upon deposition of a mixture of Q and C molecules onto a graphite surface, one might expect that hydrogen-bonded QC dimers were observed in a new 2D self-assembled structure governed by inter- and intramolecular hydrogen-bonding interactions between Q and C molecules. However, our STM experiments showed that no well-ordered structures are formed and instead phase separation occurs where large-scale homodomains are formed consisting of the individual QQ and CC dimers. To gain further insight into the possible molecular arrangements of the Q and C nucleobases in the mixture phase, the high-resolution STM images are compared with the results from ab initio density functional theory (DFT) calculations.

The synthesis of a 2'-deoxyuridine nucleoside linked to an anthraquinone moiety, and its incorporation into oligonucleotides are described, including a facile oxidative demethylation with phenyliodine(iii) bis(trifluoroacetate) to reveal the anthraquinone motif. Furthermore, some useful physical and electrochemical properties of the obtained oligonucleotide are also reported, which allow its principal use in electrochemical DNA assays.

A series of homo- and heteroditopic thymine- and/or adenine-terminated molecules incorporating rigid aryl or oligo(phenylene ethynylene) linkers has been efficiently synthesized. The key steps involved in the synthesis are the construction of the N-arylated nucleobases using the Chan-Lam-Evans-modified Ullman coupling and their further elaboration using the Sonogashira coupling. Furthermore, the synthesis of a rigid tripodal thymine derivative is reported.

The development of more selective chemotherapeutic agents for benign treatments of malicious diseases is highly desirable. In recent years model systems for the release of small molecule drugs from nucleic acid conjugates by templated chemical or photochemical reactions have been designed. Common for these systems is that the stoichiometric or catalytic drug release is controlled by the highly selective hybridization between complementary strands of nucleic acids. Herein, the concepts of the new field of nucleic acid templated release reactions are outlined.

A general approach to N-arylation and N-alkenylation of all five DNA/RNA nucleobases at the nitrogen atom normally attached to the sugar moiety in DNA or RNA has been developed. Various protected or masked nucleobases engaged readily in the copper-mediated Chan-Lam-Evans-modified Ullmann condensation with a range of different boronic acids at room temperature and were subsequently converted to the corresponding deprotected or unmasked adducts. Different N(3)-protecting groups were examined in the case of thymine, where the benzoyl group afforded the highest yields. A 4-alkylthio-substituted pyrimidin-2(1H)-one served as both a cytosine and a uracil precursor and was N-arylated and N-alkenylated in high yields. Adenine was efficiently and selectively N-arylated and N-alkenylated at the N(9) position by employing a bis-Boc-protected adenine derivative, while a bis-Boc-protected 2-amino-6-chloropurine served as guanine precursor and could also be selectively N(9)-arylated and N(9)-alkenylated.

[reaction: see text] A short synthesis of (+/-)-spectinabilin via a trans-selective Suzuki coupling and subsequent Negishi-type methylation, and its biomimetic conversion to (+/-)-SNF4435C and (+/-)-SNF4435D is described.

The total synthesis of the nitrophenyl pyrones, (+/-)-aureothin and (+/-)-N-acetylaureothamine, starting from known 2-ethyl-6-methoxy-3,5-dimethyl-4H-pyran-4-one are described. The key steps involved in the synthesis are the construction of the tetrahydrofuran motif using a palladium-catalyzed cycloaddition and the ruthenium-catalyzed cross-metathesis reaction of an alkenyl boronic ester. [reaction: see text]

The Lewis acid-mediated addition of silyl enolates to easily accessible homochiral N-acylhydrazones derived from 3-amino-2-oxazolidinones proceeded in yields up to 71% and diastereomeric ratios of 99:1. In most cases, optimal reaction conditions entailed the simple use of ZnCl(2) in acetonitrile at room temperature. Hydrazones derived from phenyl-, isopropyl-, and benzyl-substituted 2-oxazolidinones were examined in the reaction in terms of yield and diastereoselectivity. The facile SmI(2)-mediated N-N bond cleavage of the formed hydrazines was demonstrated yielding a beta-amino acid derivative. Hence, the overall reaction sequence constitutes an efficient asymmetric Mannich-type reaction. The sense of diastereoselectivity was explained by a preferential attack on the less shielded Si face of the chiral hydrazones and confirmed by means of X-ray crystallography.

Addition of ketene acetals to sulfinimines derived from homochiral N-tert-butanesulfinamide using various Lewis acids furnishes derivatives of aspartic acid in diastereomeric ratios up to 97:3. Following an easy removal of the N-tert-butanesulfinyl chiral auxiliary, optical active beta-amino esters are obtained.

A series of C4-keto-functionalized 1-[(benzoyloxy)(ethoxycarbonyl)methyl]-2-azetidinones were prepared and studied for their tendency to undergo a Reformatsky-type cyclization to fused bicyclic or tricyclic beta-lactams with the single-electron reducing agent samarium diiodide. Whereas the azetidinone 21a underwent reductive cyclization, affording the potent antibiotic sanfetrinem's tricyclic [4.5.6] core structure as the major component, all other examples tested resulted in cyclization followed by an N to O acyl migration involving cleavage of the beta-lactam ring as the favored pathway. Highly functionalized proline derivatives were therefore accessed as single diastereomers through the reductive cyclization of benzoates 21b, 22, 23a,b, 24b, and 25-28. Pertinent for the success of these cyclizations was the addition of 1 equiv of tert-butyl alcohol, allowing for the protonation of the basic amide derivative obtained after the acyl migration step. The diastereoselectivities of these reactions deviate from those of similar cyclizations involving the corresponding lithium enolate. This divergence could be rationalized by the coordination of the metal ion of the samarium(III) enolate intermediate to the beta-lactam amide functionality in the cyclization step, which may not be possible for lithium enolates.