Uncatalyzed Diboron Activation by a Strained Hydrocarbon: Experimental and Theoretical Study of [1.1.1]Propellane Diborylation.

The synthesis of strained carbocyclic building blocks is relevant for Medicinal Chemistry, and methylenecyclobutanes are particularly challenging with current synthetic technology. Careful inspection of the reactivity of [1.1.1]propellane and diboron reagents has revealed that bis(catecholato)diboron (B2cat2) can produce a bis(borylated) methylenecyclobutane in a few minutes at room temperature. This reaction constitutes the first example of B-B bond activation by a special apolar hydrocarbon and also the first time that propellane is electrophilically activated by boron. Mechanistic studies including in situ NMR kinetics and DFT calculations demonstrate that the diboron moiety can be directly activated through coordination with the inverted sigma bond of propellane, and reveal that DMF is involved in the stabilization of diboronate ylide intermediates rather than the activation of the B-B bond. These results enable new possibilities for both diboron and propellane chemistry, and for further developments in the synthesis of methylenecyclobutanes based on propellane strain release.

Nitrooxidative Stress and Neuroinflammation Caused by Air Pollutants Are Associated with the Biological Markers of Neurodegenerative Diseases.

Millions of people around the world are exposed to air pollutants, such as particulate matter 2.5 (PM2.5) and ozone (O3). Such exposure usually does not exclude these two types of pollutants and their harmful effects could be additive or synergistic. O3 is a highly oxidizing gas that reacts with the cellular environment just as PM2.5, triggering nitrooxidative damage. Once nitrooxidative stress overcomes the endogenous antioxidant system, an acute neuroinflammatory process is generated, and once it becomes chronic, it favors the formation of neurodegenerative disease markers. The presence of these markers becomes potentially dangerous in people who have a genetic predisposition and are at a higher risk of developing neurodegenerative diseases such as Alzheimer's and Parkinson's. Our experimental approach for nitrooxidative damage and neuroinflammation caused by air pollutants has focused on the exposure of rats to O3 in an isolated chamber. The hippocampus is the most studied brain structure because of its neuronal connectivity network with the olfactory epithelium, its weak antioxidant defense, and its fundamental roll in cognitive processes. However, other brain structures may exhibit a different degree of damage upon exposure to O3 and PM2.5, making their involvement an important factor in developing other CNS diseases. The age spectrum for augmented sensibility to air pollutants seems to mostly affect the pre-postnatal (autism spectrum) period and the elderly (neurodegenerative). Thus, a new approach could be the estimation of the damage caused by PM2.5 and O3 through a controlled exposure paradigm to determine the extent of damage caused by both pollutants.

Synthesis and Evaluation of Antifungal and Antibacterial Abilities of Carbon Nanotubes Grafted to Poly(2-hydroxyethyl methacrylate) Nanocomposites.

Developing nanomaterials with the capacity to restrict the growth of bacteria and fungus is of current interest. In this study, nanocomposites of poly(2-hydroxyethyl methacrylate) (PHEMA) and carbon nanotubes (CNTs) functionalized with primary amine, hydroxyl, and carboxyl groups were prepared and characterized. An analysis by Fourier-transform infrared (FT-IR) spectroscopy showed that PHEMA chains were grafted to the functionalized CNTs. X-ray photoelectron spectroscopy suggested that the grafting reaction was viable. The morphology of the prepared nanocomposites studied by field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) showed significant changes with respect to the observed for pure PHEMA. The thermal behavior of the nanocomposites studied by differential scanning calorimetry (DSC) revealed that the functionalized CNTs strongly affect the mobility of the PHEMA chains. Tests carried out by thermogravimetric analysis (TGA) were used to calculate the degree of grafting of the PHEMA chains. The ability of the prepared nanocomposites to inhibit the growth of the fungus Candida albicans and the bacteria Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli was evaluated. A reduced antifungal and antibacterial capacity of the prepared nanocomposites was determined.

Effective Removal of Cu2+ Ions from Aqueous Media Using Poly(acrylamide-co-itaconic acid) Hydrogels in a Semi-Continuous Process.

Adsorption is one of the most crucial processes in water treatment today. It offers a low-cost solution that does not require specialized equipment or state-of-the-art technology while efficiently removing dissolved contaminants, including heavy metals. This process allows for the utilization of natural or artificial adsorbents or a combination of both. In this context, polymeric materials play a fundamental role, as they enable the development of adsorbent materials using biopolymers and synthetic polymers. The latter can be used multiple times and can absorb large amounts of water per gram of polymer. This paper focuses on utilizing adsorption through hydrogels composed of poly(acrylamide-co-itaconic acid) for removing Cu2+ ions dissolved in aqueous media in a semi-continuous process. The synthesized hydrogels were first immersed in 0.1 M NaOH aqueous solutions, enabling OH- ions to enter the gel matrix and incorporate into the polymer surface. Consequently, the copper ions were recovered as Cu(OH)2 on the surface of the hydrogel rather than within it, allowing the solid precipitates to be easily separated by decantation. Remarkably, the hydrogels demonstrated an impressive 98% removal efficiency of the ions from the solution in unstirred conditions at 30 °C within 48 h. A subsequent study involved a serial process, demonstrating the hydrogels' reusability for up to eight cycles while maintaining their Cu2+ ion recovery capacity above 80%. Additionally, these hydrogels showcased their capability to remove Cu2+ ions even from media with ion concentrations below 100 ppm.

Modular Synthesis of (Borylmethyl)silanes through Orthogonal Functionalization of a Carbon Atom.

(Borylmethyl)trimethylsilanes are important building blocks in organic synthesis displaying a unique reactivity. Yet, the synthesis of more advanced derivatives is limited by the advanced silicon intermediates required for their preparation. Herein, a one-pot synthesis of (borylmethyl)silanes is developed, sourced on available alkyl-, aryl-, alkoxy-, aryloxy-, and silyl-hydrosilane materials. The privileged reactivity of N-hydroxyphthalimidyl diazoacetate (NHPI-DA) in Si-H insertion and α-silyl redox-active esters in different decarboxylative borylation reactions are scrutinized.

Pararectus Approach in Acetabular Fractures in Patients Older Than 65 years. Is it Possible to Improve the Technique?

OBJECTIVES: Review clinical results of the treatment for acetabular fractures using the pararectus approach and analyze surgical variations of the traditional approach. DESIGN: Retrospective. SETTING: Tertiary referral hospital. PATIENTS: 46 patients over 65 years of age who sustained an acetabular fracture and underwent surgery using the pararectus approach. INTERVENTION: Fractures were treated using a pararectus approach. Three variations of the original technique were performed: (1) Ligature of the deep iliac circumflex artery and vein, (2) separation of the psoas and iliacus muscles, and (3) isolation of the spermatic cord in men and round ligament in women together with the iliac and epigastric vessels. MAIN OUTCOME MEASUREMENTS: Outcomes measures included surgical, demographic, and clinical data, and information related to follow-up. RESULTS: Duration of surgery, 125 minutes (95-210). Quality of reduction on postoperative computed tomography (CT) scan; anatomic in 22 patients (47.8%), incomplete in 16 (34.8%), and poor in 8 (17.4%). In patients in whom the hip was preserved (n = 41), functional status was excellent in 15 patients (36.5%), good in 17 (41.4%), fair in 6 (14.7%), and poor in 3 (7.4%), with mean functional score of 16 points (7-18). Seven patients (15.2%) developed posttraumatic osteoarthritis and 4 of these patients underwent total hip replacement. CONCLUSIONS: This study reports positive outcomes in fracture reduction and clinical outcomes with low complications in older patients who suffered acetabular fractures and were treated using a pararectus approach. Small variations in the technique, such as those proposed in this study, may help to widen access to the surgical site and simplify the technique. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Infecciones peribucales en la infancia: presentación de dos casos clínicos de impétigo / Infecções peri-orais na infância: Apresentação de dois casos clínicos de impetigo / Perioral infections in childhood. Presentation of two clinical case of impetigo

Existen diversos diagnósticos clínicos diferenciales de lesiones infectocontagiosas peribucales en la infancia, siendo las más frecuentes: herpes labial, queilitis angular (queilocandidiasis) e impétigo, esta última es una infección bacteriana prevalente en población infantil, afectando la región labial y peribucal, cuyo diagnóstico está principalmente basado en los hallazgos clínicos y en el análisis minucioso de la anamnesis. Objetivo: Presentar dos casos clínicos de impétigo ampolloso en pacientes pediátricos, destacando sus características, comparándolas y contrastándolas con sus principales diagnósticos diferenciales. Reporte de casos. Se presentan dos casos de pacientes masculinos de 10 años (hermanos gemelos) con antecedentes de secuencia de Pierre Robin, los cuales acudieron a la clínica de Odontopediatría de la ENES, UNAM, unidad León, presentando múltiples lesiones ulcerativas, localizadas área peribucal, refiriendo dos semanas de evolución. Diagnóstico. Se estableció el diagnóstico clínico de: impétigo ampolloso, para ambos pacientes. Plan de tratamiento. Se indicaron medidas estrictas de higiene general y en las zonas afectadas, eliminando también cualquier objeto que actuara como fómite, evitando compartir productos de aseo personal, además, se indicó la aplicación de mupirocina en crema al 2%, llevándose a cabo el seguimiento a los 14 y 30 días hasta la curación completa. Conclusiones. El impétigo peribucal es frecuentemente confundido con otras infecciones presentes en esa localización con manifestaciones clínicas semejantes en algunos casos suele ser tratado erróneamente. Por lo que se destaca la importancia de realizar un adecuado interrogatorio, una exploración clínica concienzuda y realizar un análisis diferencial clínico en este tipo de lesiones.

Existem vários diagnósticos clínicos diferenciais de lesões periorais infecciosas na infância, sendo os mais frequentes: herpes labial, queilite angular (queilocandidíase) e impetigo, sendo este último uma infecção bacteriana prevalente em crianças, acometendo a região labial e perioral, cujo diagnóstico é principalmente baseado em achados clínicos e na análise cuidadosa da anamnese. Objetivo: Apresentar dois casos clínicos de impetigo bolhoso em pacientes pediátricos, destacando as características, comparando-os e contrastando-os com os principais diagnósticos diferenciais. Relato de caso. Apresentam-se dois casos de pacientes do sexo masculino (irmãos gêmeos) de 10 anos de idade com histórico de sequência de Pierre Robin, que compareceram à clínica de Odontopediatria da ENES, UNAM, unidade León, apresentando múltiplas lesões ulcerativas, localizadas na zona perioral, referindo duas semanas de evolução. Diagnóstico. Estabeleceu-se o diagnóstico clínico de: impetigo bolhoso para ambos os pacientes. Plano de tratamento. Foram indicadas medidas rigorosas de higiene geral e nas áreas afetadas, eliminando também qualquer objeto que atuasse como fômite, evitando o compartilhamento de produtos de higiene pessoal, além disso, foi indicada a aplicação de creme de mupirocina 2%, realizando o acompanhamento em 14 e 30 dias até a cura completa. Conclusões. Frequentemente, o impetigo perioral é confundido com outras infecções presentes nessa localização com manifestações clínicas semelhantes e, em alguns casos, geralmente é tratado erroneamente. Destaca-se, portanto, a importância de se realizar um interrogatório adequado, um exame clínico minucioso e uma análise clínica diferencial neste tipo de lesões

There are several differential clinical diagnoses of infectious perioral lesions in childhood, the most frequent being: herpes labialis, angular cheilitis (cheilocandidiasis) and impetigo, the latter being a bacterial infection prevalent in children, with rupture of the labial and perioral region, whose diagnosis is mainly based on clinical findings and careful analysis of the anamnesis. Objective: To present two clinical cases of bullous impetigo in pediatric patients, highlighting their characteristics, comparing, and contrasting them with their main differential diagnoses. Case report. We present two cases of 10-year-old male patients (twin brothers) with a history of Pierre Robin sequence, who attended the Pediatric Dentistry clinic of the ENES, UNAM, León unit, presenting multiple ulcerative lesions, located in the perioral area, referring two weeks of evolution. Diagnosis. The clinical diagnosis of: bullous impetigo is established for both patients. Treatment plan. Strict general hygiene measures were indicated and in the affected areas, also eliminating any object that acted as a fomite, preventing the sharing of personal hygiene products, in addition, the application of mupirocin cream at 2% was shown, carrying out the monitoring of the 14 and 30 days until complete healing. Conclusions. Perioral impetigo is frequently confused with other infections present in that location with similar clinical manifestations. In some cases, it is usually treated incorrectly. Therefore, the importance of carrying out an adequate interrogation, a thorough clinical examination and performing a clinical differential analysis in this type of injury is highlighted.

Curcumin Modifies the Activity of Plasmatic Antioxidant Enzymes and the Hippocampal Oxidative Profile in Rats upon Acute and Chronic Exposure to Ozone.

Ozone (O3) is an oxidating tropospheric pollutant. When O3 interacts with biological substrates, reactive oxygen and nitrogen species (RONS) are formed. Severe oxidative damage exhausts the endogenous antioxidant system, which leads to the decreased activity of antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD). Curcumin (CUR) is a natural polyphenol with well-documented antioxidant and anti-inflammatory properties. The aim of this work is to evaluate the effects of curcumin on CAT, GPx, and SOD activity and the inhibition of oxidative damage after the acute and chronic exposure to O3. Fifty male Wistar rats were divided into five experimental groups: the intact control, CUR-fed control, exposed-to-O3 control, CUR-fed (preventive), and CUR-fed (therapeutic) groups. These two last groups received a CUR-supplemented diet while exposed to O3. These experiments were performed during acute- and chronic-exposure phases. In the preventive and therapeutic groups, the activity of plasma CAT, GPx, and SOD was increased during both exposure phases, with slight differences; concomitantly, lipid peroxidation and protein carbonylation were inhibited. For this reason, we propose that CUR could be used to enhance the activity of the antioxidant system and to diminish the oxidative damage caused by exposure to O3.

Semi-Continuous Heterophase Polymerization to Synthesize Poly(methacrylic acid)-Based Nanocomposites for Drug Delivery.

The design of nanocomposites with the potential for drug delivery is a topic of great interest. In this work, the synthesis of nanocomposites of poly(methacrylic acid) (PMAA) grafted onto carbon nanotubes (CNTs) functionalized with poly(amidoamine) (PAMAM) dendrimer by semicontinuous heterophase polymerization SHP, at three different methacrylic acid (MAA) dosing rates, is reported. SHP is a polymerization technique poorly used to prepare nanocomposites containing CNTs and has the potential to produce more ordered alkyl methacrylic polymer chains, which could favor the obtaining of a homogenous nanocomposite. For the nanocomposites synthesized, a lowest addition rate monomer-starved condition was reached. Analysis by X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) demonstrate that functionalized CNTs are grafted onto the PMAA matrix. The ability of prepared nanocomposites to deliver hydrocortisone was evaluated by ultraviolet-visible spectroscopy (UV-Vis). The hydrocortisone release profiles of pure PMAA and of their nanocomposites prepared at the lowest monomer fed rate were fitted with Higuchi and Korsmeyer-Peppas models, successfully. Functionalized CNTs have a crucial role to induce an effective release of hydrocortisone from the prepared nanocomposites.

Direct Addition of Grignard Reagents to Aliphatic Carboxylic Acids Enabled by Bulky turbo-Organomagnesium Anilides.

Invited for the cover of this issue is the group of Abraham Mendoza at Stockholm University. The image depicts a Grignard reagent "turbo-charged" with a magnesium anilide additive. Read the full text of the article at 10.1002/chem.202104053.

An application of interactive fuzzy optimization model for redesigning supply chain for resilience.

Supply chain disruptions compel professionals all over the world to consider alternate strategies for addressing these issues and remaining profitable in the future. In this study, we considered a four-stage global supply chain and designed the network with the objectives of maximizing profit and minimizing disruption risk. We quantified and modeled disruption risk as a function of the geographic diversification of facilities called supply density (evaluated based on the interstage distance between nodes) to mitigate the risk caused by disruptions. Furthermore, we developed a bi-criteria mixed-integer linear programming model for designing the supply chain in order to maximize profit and supply density. We propose an interactive fuzzy optimization algorithm that generates efficient frontiers by systematically taking decision-maker inputs and solves the bi-criteria model problem in the context of a realistic example. We also conducted disruption analysis using a discrete set of disruption scenarios to determine the advantages of the network design from the bi-criteria model over the traditional profit maximization model. Our study demonstrates that the network design from the bi-criteria model has a 2% higher expected profit and a 2.2% lower profit variance under disruption than the traditional profit maximization solution. We envisage that this model will help firms evaluate the trade-offs between mitigation benefits and mitigation costs.

Direct Addition of Grignard Reagents to Aliphatic Carboxylic Acids Enabled by Bulky turbo-Organomagnesium Anilides.

The synthesis of ketones through addition of organometallic reagents to aliphatic carboxylic acids is a straightforward strategy that is limited to organolithium reagents. More desirable Grignard reagents can be activated and controlled with a bulky aniline-derived turbo-Hauser base. This operationally simple procedure allows the straightforward preparation of a variety of aliphatic and perfluoroalkyl ketones alike from functionalized alkyl, aryl and heteroaryl Grignard reagents.

Modular Enantioselective Synthesis of cis-Cyclopropanes through Self-Sensitized Stereoselective Photodecarboxylation with Benzothiazolines.

Chiral cis-cyclopropanes are strained rigid analogues of alkyl chains, whose study and application are limited by their difficult synthesis. A modular approach from olefin materials is enabled by the discovery of the electron donor-acceptor (EDA) interaction between 2-substituted benzothiazolines and N-hydroxyphthalimide esters. These complexes are activated by visible light without photocatalysts, and the benzothiazoline reagent plays a triple role as a photoreductant, a stereoselective hydrogen-atom donor, and a Brønsted acid. Beyond the enantioselective synthesis of cis-cyclopropanes, these results introduce benzothiazolines as accessible and easily tunable self-sensitized photoreductants.

Combined Experimental and Computational Study of Ruthenium N-Hydroxyphthalimidoyl Carbenes in Alkene Cyclopropanation Reactions.

A combined experimental-computational approach has been used to study the cyclopropanation reaction of N-hydroxyphthalimide diazoacetate (NHPI-DA) with various olefins, catalyzed by a ruthenium-phenyloxazoline (Ru-Pheox) complex. Kinetic studies show that the better selectivity of the employed redox-active NHPI diazoacetate is a result of a much slower dimerization reaction compared to aliphatic diazoacetates. Density functional theory calculations reveal that several reactions can take place with similar energy barriers, namely, dimerization of the NHPI diazoacetate, cyclopropanation (inner-sphere and outer-sphere), and a previously unrecognized migratory insertion of the carbene into the phenyloxazoline ligand. The calculations show that the migratory insertion reaction yields an unconsidered ruthenium complex that is catalytically competent for both the dimerization and cyclopropanation, and its relevance is assessed experimentally. The stereoselectivity of the reaction is argued to stem from an intricate balance between the various mechanistic scenarios.

Curcumin Decreases Hippocampal Neurodegeneration and Nitro-Oxidative Damage to Plasma Proteins and Lipids Caused by Short-Term Exposure to Ozone.

Neurodegeneration is the consequence of harmful events affecting the nervous system that lead to neuronal death. Toxic substances, including air pollutants, are capable of inducing neurodegeneration. Ozone (O3) is the most oxidative toxic pollutant. O3 reacts with cellular components and forms reactive oxygen and nitrogen species, triggering nitro-oxidative damage during short-term exposure. Curcumin (CUR) is a natural phenolic molecule bearing well-documented antioxidant and anti-inflammatory biological activities in diverse experimental models. The aim of this work was to evaluate the effect of preventive dietary administration of CUR against hippocampal neurodegeneration and nitro-oxidative damage caused by short-term exposure to O3. Eighty Wistar male rats were distributed into four experimental groups, twenty rats each: intact control; CUR dietary supplementation without O3 exposure; exposure to 0.7 ppm of O3; and exposed to O3 with CUR dietary supplementation. Five rats from each group were sacrificed at 1, 2, 4, and 8 h of exposure. The CUR dose was 5.6 mg/kg and adjusted according to food consumption. CUR significantly decreased oxidative damage to plasma lipids and proteins, as well as neurodegeneration in CA1 and CA3 hippocampal regions. Concluding, CUR proved effective protection in decreasing neurodegeneration in the hippocampus and prevented systemic oxidative damage.

Temperature should not be measured on forearm with infrared thermometers for Covid-19 screening.

Not available.

N-Hydroxyphthalimidyl diazoacetate (NHPI-DA): a modular methylene linchpin for the C-H alkylation of indoles.

Despite the extensive studies on the reactions between conventional diazocompounds and indoles, these are still limited by the independent synthesis of the carbene precursors, the specific catalysts, and the required multi-step manipulation of the products. In this work, we explore redox-active carbenes in the expedited and divergent synthesis of functionalized indoles. NHPI-DA displays unusual efficiency and selectivity to yield insertion products that can be swiftly elaborated into boron and carbon substituents that are particularly problematic in carbene-mediated reactions.

Computational and Experimental Study of Turbo-Organomagnesium Amide Reagents: Cubane Aggregates as Reactive Intermediates in Pummerer Coupling.

The dynamic equilibria of organomagnesium reagents are known to be very complex, and the relative reactivity of their components is poorly understood. Herein, a combination of DFT calculations and kinetic experiments is employed to investigate the detailed reaction mechanism of the Pummerer coupling between sulfoxides and turbo-organomagnesium amides. Among the various aggregates studied, unprecedented heterometallic open cubane structures are demonstrated to yield favorable barriers through a concerted anion-anion coupling/ S-O cleavage step. Beyond a structural curiosity, these results introduce open cubane organometallics as key reactive intermediates in turbo-organomagnesium amide mixtures.

Decarboxylative Alkyl Coupling Promoted by NADH and Blue Light.

Photoexcited dihydronicotinamides like NADH and analogues have been found to generate alkyl radicals upon reductive decarboxylation of redox-active esters without auxiliary photocatalysts. This principle allowed aliphatic photocoupling between redox-active carboxylate derivatives and electron-poor olefins, displaying surprising water and air-tolerance and unusually high coupling rates in dilute conditions. The orthogonality of the reaction in the presence of other carboxylic acids and its utility in the functionalization of DNA is presented, notably using visible light in combination with NADH, the ubiquitous reductant of life.