Bromine Substitution Effect on Structure, Reactivity, and Linear and Third-Order Nonlinear Optical Properties of 2,3-Dimethoxybenzaldehyde.

The structural and electronic properties of 2,3-dimethoxybenzaldehyde (2,3-DMB), 5-bromo-2,3-dimethoxybenzaldehyde (5-BRB), and 6-bromo-2,3-dimethoxybenzaldehyde (6-BRB) were extensively discussed with emphasis on linear and nonlinear optical responses. The intermolecular interactions were comparatively studied by Hirshfeld surfaces, quantum theory of atoms in molecules (QTAIM), and natural bond orbitals (NBOs), indicating that bromine substitution decreases the H···H and C···H contacts and increases H···Br and Br···Br closed-shell interactions on crystalline arrangements. The frontier molecular orbitals and molecular electrostatic potential map, carried out at the CAM-B3LYP/6-311++G(d,p) level of theory, showed that the kinetic stability occurs in the increasing order 6-BRB < 5-BRB < 2.3-DMB. The bromine atom has a beneficial effect on the nonlinear third-order susceptibility of 2,3-DMB, with theoretical predictions of 89.54 ×10-22 and 83.15 ×10-22 (m/V)2 for 6-BRB and 5-BRB, respectively. These findings were favorably compared with available theoretical and experimental data of other organic crystals that may be promising as NLO materials.

Chiral C2 -symmetric bis-thioureas as enzyme mimics in enantioselective Michael addition.

We report herein the synthesis and application of enantiopure C2 -symmetric primary amine-1,3-bis-thiourea organocatalysts in enantioselective conjugate 1,4-Michael addition of carbonyl containing nucleophiles, to nitroalkenes and N-phenylmaleimide, leading to final products in good enantioselectivities (up to 99%) and yields (up to 99%). We propose supramolecular noncovalent interactions within the organocatalyst's cleft between the substrate and the catalyst, via hydrogen bonding. Supramolecular interaction thus lowers the transition state energy mimicking an enzyme. Mechanism underlying our experimental results is supported by theorical calculations.

Mononuclear and Tetranuclear Copper(II) Complexes Bearing Amino Acid Schiff Base Ligands: Structural Characterization and Catalytic Applications.

Two new glycine-Schiff base copper(II) complexes were synthesized. Single crystal X-ray diffraction (SCXRD) allowed us to establish the structure of both complexes in the solid state. The glycine-Schiff base copper(II) complex derived from 2'-hydroxy-5'-nitroacetophenone showed a mononuclear hydrated structure, in which the Schiff base acted as a tridentate ligand, and the glycine-Schiff base copper(II) complex derived from 2'-hydroxy-5'-methylacetophenone showed a less common tetranuclear anhydrous metallocyclic structure, in which the Schiff base acted as a tetradentate ligand. In both compounds, copper(II) had a tetracoordinated square planar geometry. The results of vibrational, electronic, and paramagnetic spectroscopies, as well as thermal analysis, were consistent with the crystal structures. Both complexes were evaluated as catalysts in the olefin cyclopropanation by carbene transference, and both led to very high diastereoselectivity (greater than 98%).

Novel Linezolid analogues with antiparasitic activity against Hymenolepis nana.

The stereoselective synthesis and anti- Hymenolepis nana activity of six Linezolid-type compounds, obtained by chemical modification of l-Alanine, are reported in this work. The synthetic strategy was to prepare diasteromeric N,N-dibenzylamino oxazolidinones 1 and 2, and coupling with 4-(4-bromophenyl)morpholine (3) to obtain N,N-dibenzylamino Linezolid analogues 4 and 5. A hydrogenolysis reaction over 4 and 5 resulted in amino-free Linezolid analogues 6 and 7, which were acetylated to reach diasteromeric Linezolid analogues 8 and 9. The six Linezolid analogues 4-9 show in vitro antiparasitic activity against Hymenolepis nana cestode, but not against several bacterial strains. Interestingly, compounds 6, 7 and 9 exhibit high potency, having shorter paralysis and death times after exposure (6-10 and 18-21 min, respectively), shorter than those found with antihelmintic compound Praziquantel (20 and 30 min) at 20 mg/mL. In addition, a cytocompatibility assay of 6-9 with human cells (ARPE-19 cells) demonstrate a non-cytotoxic effect at 0.4 mM. These results show the pharmacological potential of the newly reported Linezolid-type analogues as antiparasitic agents against Hymenolepis nana.

Anti-VEGF treatment switch in neovascular age-related macular degeneration: a comparison of aflibercept versus ranibizumab after a single-dose switch.

PURPOSE: To determine the effect achieved from a single dose of anti-VEGF treatment switch, in patients with nAMD previously treated with bevacizumab, switched to either aflibercept or ranibizumab, and to compare the response between aflibercept and ranibizumab. METHODS: In retrospective, observational, and comparative study, patients were divided into two groups: Group 1, patients switched to aflibercept; Group 2, patients switched to ranibizumab. Paired samples t test was performed to measure differences in central macular thickness (CMT). To compare whether there were differences between groups mixed-design ANOVA was used. RESULTS: In Group 1, CMT changed from 360.51 to 260.16 µm, presenting a significant mean difference from PreSwitch to PostSwitch of 100.34 µm (p = 0.002, paired samples t test). In Group 2, CMT changed from 366.33 to 260.72 µm, showing a significant difference from PreSwitch to PostSwitch of 105.61 µm (p ≤ 0.000, paired samples t test). The mixed-design ANOVA compared both groups and resulted in a nonsignificant value of 0.90. CONCLUSION: The effect achieved from a single dose in patients switched to aflibercept or ranibizumab reduced significantly CMT measurements. Comparing aflibercept and ranibizumab, the effect appears to be similar in both drugs, in terms of reduction of CMT.

C2 -symmetric sulfonamides as homogeneous and heterogeneous organocatalysts that mimic enzymes in enantioselective Michael additions.

Herein, we report the synthesis of C2 -symmetric sulfonamides as homogeneous and heterogeneous organocatalysts and their application in the enantioselective conjugate 1,4-Michael addition of carbonylic nucleophiles to ß-nitrostyrene. Organocatalysts hydrogen bond to ß-nitrostyrene and enamine in the transition state, mimicking an enzyme leading to final products in high yields (up to 98%) and good enantioselectivities (up to 96%). In addition, these results were supported by density functional calculations.

New insights in diagnosis and treatment for Retinopathy of Prematurity.

The purpose of this study was to review current perspectives on diagnosis and treatment of Retinopathy of Prematurity (ROP). We performed a systematic review of how much has been produced in research published online and on print regarding ROP in different settings around the world. Early Treatment for ROP (ETROP) classification is the currently accepted classification of ROP. Fluorescein angiography and spectral domain optical coherence tomography (SD-OCT) may eventually lead to changes in the definition of ROP, and as a consequence, they will serve as a guide for treatment. Intravitreal anti-VEGF therapy has proven to be more effective in terms of lowering recurrence, allowing growth of the peripheral retina, and diminishing the incidence of retinal detachment when proliferative ROP is diagnosed. Whether anti-VEGF plus laser are better than any of these therapies separately remains a subject of discussion. Telemedicine is evolving everyday to allow access to remote areas that do not count with a retina specialist for treatment. A management algorithm is proposed according to our reference center experience. ROP is an evolving subject, with a vulnerable population of study that, once treated with good results, leads to a reduction in visual disability and in consequence, in a lifetime improvement.

Multimodal Imaging of an Idiopathic Vascularized Epiretinal Membrane: A Case Report.

BACKGROUND Idiopathic epiretinal membranes (ERMs) are commonly associated with fibrovascular tissue, primarily observed in ischemic retinopathies. However, idiopathic vascularized ERMs (IVEM) are exceedingly rare, and their pathogenesis and clinical course remain poorly understood. This report aims to contribute to the limited literature on IVEM, shedding light on its characteristics and potential implications for patient management. CASE REPORT We present the case of a 70-year-old man diagnosed with idiopathic ERM in the left eye, revealing a neovascular complex within the membrane. Despite the absence of ocular symptoms and medical history, multimodal imaging using the Nidek Mirante, including spectral domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCT-A), revealed a thick pre-retinal hyper-reflective line with a partial posterior vitreous detachment and an abnormal vascular complex resembling a pruned-vascular-tree pattern. Notably, fluorescein angiography confirmed hyperfluorescence and leakage corresponding to the observed vessels. Despite the rarity of IVEM, the patient remained asymptomatic, and observation was deemed appropriate. CONCLUSIONS IVEM poses a rare challenge in clinical practice, necessitating a comprehensive understanding of its features and potential complications. While the etiopathogenesis remains unclear, hypertension has been proposed as a contributing factor. This case adds valuable insights to the growing literature on IVEM, emphasizing the importance of multimodal imaging in diagnosis and decision-making. Given the limited reports and varied treatment outcomes, managing IVEM requires careful consideration of observation and various therapeutic approaches, highlighting the need for further research to optimize patient care.

Ruthenium complexes with triazenide ligands bearing an N-heterocyclic moiety, and their catalytic properties in the reduction of nitroarenes.

A series of ruthenium complexes of formulae [RuCl(triazenide)(p-cymene)] have been synthesized using as ligand a triazenide monofunctionalized with an N-heterocyclic moiety. Nuclear magnetic resonance, high resolution mass spectrometry and X-ray diffraction were used to characterize the triazenide ligands and their complexes. In addition, these ruthenium complexes catalyzed the reduction of nitrobenzene to aniline in the presence of sodium borohydride and ethanol as solvent at room temperature. Notably, complex 5 was especially active in the reduction of nitroarenes substituted at the aromatic ring with electron-withdrawing or electron-donating fuctional groups affording the desired arylamines in good to excellent yields (80-100%). The role of the N-heterocyclic moiety on catalysis was explored.

Long-term effect of antiangiogenic therapy for retinopathy of prematurity up to 5 years of follow-up.

PURPOSE: To evaluate ocular function and systemic development in premature infants treated with intravitreal bevacizumab injections for retinopathy of prematurity over a period of 5 years. METHODS: A prospective, interventional, noncomparative case study. The primary outcome measure was visual acuity. The secondary outcomes were structural assessment, other ocular functional measurements, and developmental state. RESULTS: Eighteen eyes of 13 consecutive patients were divided into 3 groups: Group 1, Stage 4 unresponsive to previous conventional treatment (n = 4); Group 2, in which conventional treatment was difficult or impossible because of inadequate visualization of the retina (n = 5); and Group 3, newly diagnosed high-risk prethreshold or threshold retinopathy of prematurity (n = 9). All patients showed initial regression of neovascularization. One patient was diagnosed with recurrence of neovascularization and was treated with intravitreal bevacizumab. Visual acuity was preserved, and median vision was 20/25 (excluding 2 operated eyes). Twelve eyes developed mainly low myopia over the years, with an overall mean value of 3.2 diopters. Electroretinograph was normal in 4 eyes that had no previous detachment. One patient showed delay in growth and neurodevelopment, whereas all the others were within the normal range. CONCLUSION: Five years of follow-up in a small series suggest that intravitreal bevacizumab for retinopathy of prematurity results in apparently preserved ocular function and systemic development.

2,3,4,5,6-Penta-fluoro-trans-cinnamic acid.

The title compound, C9H3F5O2, crystallizes as O-H⋯O hydrogen-bonded carb-oxy-lic acid dimers that, together with C-H⋯F inter-actions and O⋯F [2.8065 (13) and 2.9628 (13) Å] and F⋯F [2.6665 (11), 2.7049 (12) and 2.7314 (12) Å] contacts, form a sheet-like structure. The sheets are stacked via short π-π inter-actions [centroid-centroid distance = 4.3198 (11) Å]. An intra-molecular C-H⋯F inter-action is also observed.

4-Hy-droxy-6-methyl-pyridin-2(1H)-one.

In the crystal structure of the title compound, C6H7NO2, N-H⋯O and O-H⋯O hydrogen bonds link the mol-ecules, forming a zigzag array along [001] and a layer structure parallel to the ab plane.

The effect of water molecules on paraquat salts: from physicochemical properties to environmental impact in the Brazilian Cerrado.

Introduction: The green revolution model that is followed in the Brazilian Cerrado is dependent on mechanization, chemical fertilization for soil dressing and correction, and the use of herbicides. Paraquat is a methyl viologen herbicide marketed as bipyridylium dichloride salts and used (in low doses) to combat weeds in their post-emergence stage. It is a non-selective pesticide that causes the peroxidation of the lipids that make up the cell membrane, and when it comes into contact with foliage, it results in the death of the plant. Methods: The effect of water molecules co-crystallized in Paraquat salt structures was analyzed in anhydrous, dihydrate, and trihydrate forms to understand those physicochemical properties in its redox activity. The frontier molecular orbitals were also carried out using DFT to obtain the chemical reactivity of the bipyridylium cation. Finally, the supramolecular arrangements were evaluated to analyze the physicochemical stability and acquire insights on superoxide anions. Results and discussion: The electronic structure indicated that the BP cation presents an acidic character due to its low ELUMO value, while the salt has a more basic character due to its high EHOMO value. For this reason, the BP ion is more susceptible to reduction during the weeds' photosynthesis process. During the process of plant photosynthesis, PQ is reduced to form a stable radical cation. In the supramolecular arrangement, the presence of water molecules increases the number of strong H-bonds, while the weak/moderate H-bonds are stabilized. PQ's toxic effects are observed in wildlife, domesticated animals, human populations, and ecosystems. The influence of PQ on the terrestrial environment is limited because of the soil adsorption capacity associated with good agricultural practices. The current use of good agricultural practices in the Cerrado seems not to prevent the environmental impacts of herbicides like PQ because it aims for the expansion and profitability of large-scale farming based on input-intensive practices instead of sustainable agriculture processes.

Prevalence of Dome-Shaped Macula and Tilted Disc Syndrome in High Myopia.

BACKGROUND AND OBJECTIVE: Dome-shaped macula (DSM) and tilted disc syndrome (TDS) are two macular abnormalities that may occur in eyes with high myopia. The aim of this study was to determine the prevalence of both entities in our population. PATIENTS AND METHODS: This was a prospective and observational study. Optical coherence tomography of the macula was performed in eyes with high myopia (spherical equivalent [SE] of -8D or greater) to assess the prevalence of DSM and TDS. RESULTS: Sixty-eight eyes were included. Three eyes (4.41%) had DSM and 8 (11.76%) eyes had TDS. The most common macular anomaly was posterior staphyloma (PS) (12 [17.65%]). From the eyes with DSM (n = 3), only two presented PS. An older age and a higher SE were predisposing factors for PS (P = 0.003). CONCLUSIONS: A lower prevalence of DSM and a higher prevalence of TDS was observed in our population compared to those reported in literature. [Ophthalmic Surg Lasers Imaging Retina 2023;54:568-572.].

Early-Phase Perceptions of COVID-19's Impact on Ophthalmology Practice Patterns: A Survey from the Pan-American Association of Ophthalmology.

Purpose: The COVID-19 pandemic affected medical practice worldwide due to interventions to prevent spreading. Its effect on ophthalmology practices in Latin America has not yet been explored. We aimed to assess the perceptions about the pandemic from countries' ophthalmological national and subspecialty retina societies affiliated to the Pan-American Association of Ophthalmology (PAAO). Patients and Methods: A survey-based study of leaders of national ophthalmological and retinal societies was conducted. The survey was sent by email to 30 societies, from which 20 responded (12 countries, 66.6% response rate). It included closed- and open-ended questions about (1) operational capacity and precautions, (2) telemedicine and virtual care, (3) procedures, and (4) post-pandemic considerations. Results: There was a marked decline in ophthalmology patient visits (80-95%) and elective surgeries (90%) during 2020 compared to before the pandemic. Precautions like temperature checks, mask usage, and social distancing were widely implemented while personal protective equipment (PPE) availability varied. Telemedicine use was limited due to lack of experience with it. Reopening plans focused on maintaining precautions and gradually resuming activities. Economic and security concerns were raised, and adherence to guidelines was emphasized. Respondents acknowledged the need to adapt to a "new normal". Long duration drugs, fewer imaging studies, and shorter wait times were preferred; however, availability of long duration drugs was limited. Conclusion: The pandemic impacted ophthalmology in Latin America, with reduced patient visits, procedures, and surgeries. Delayed treatment and complications were likely the result of the pandemic.

Multifocal electrophysiologic findings after intravitreal bevacizumab (avastin) treatment.

PURPOSE: To determine the short-term safety of intravitreal bevacizumab by multifocal electroretinography testing. METHODS: Thirty-one eyes with choroidal neovascularization, proliferative diabetic retinopathy, and retinal vein occlusion received intravitreal bevacizumab (2.5 mg/0.1 mL). All patients underwent best-corrected visual acuity measurement, retinal fluorescein angiography, optical coherence tomography, and multifocal electroretinography at baseline and 1 month after the treatment. RESULTS: Subjects undergoing multifocal electroretinography testing had no statistically significant changes in electrophysiologic responses 1 month after the intravitreal injection of bevacizumab. CONCLUSION: Multifocal electrophysiologic testing did not demonstrate any short-term cone photoreceptor toxicity after intravitreal bevacizumab.

(2-tert-Butyl-5-hy-droxy-methyl-1,3-dioxan-5-yl)methanol.

In the title compound, C(10)H(20)O(4), the dioxane ring adopts a chair conformation. The tert-butyl group occupies an equatorial position, and is staggered with respect to the O atoms of the dioxane ring. In the crystal, mol-ecules are connected by O-H⋯O hydrogen-bonds into zigzag chains of R(4) (4)(8) and R(2) (2)(12) ring motifs that run parallel to the a axis.

1,3,5-Tris(pyridin-3-yl)-2,4-diaza-penta-1,4-diene.

In the solid state, the structure of the title compound, C(18)H(15)N(5), is stabilized by weak C-H⋯N interactions. Mol-ecules are arranged in layers parallel to the bc plane forming an inter-esting supra-molecular structure.

2,4,5-Tris(pyridin-4-yl)-4,5-dihydro-1,3-oxazole.

In the title compound, C(18)H(14)N(4)O, the mol-ecules are disordered about a crystallographic twofold axis, leading to 50:50 disorder of the O- and N-atom sites within the oxazole ring. As a consequence, symmetry-related oxazole C-N and C-O bonds are averaged. The oxazole ring makes a dihedral angle of 6.920 (1)° with the pyridyl ring in the 2-position and 60.960 (2)° with the pyridyl rings in the 4- and 5-positions.