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1.
Chemistry ; 30(29): e202304291, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38490950

RESUMO

The reaction between bis(1,2,3-triazol-1-yl)methane derivatives and nBuLi and various aldehydes, yielded novel neutral ligand precursors incorporating alcohol functional groups. The resulting compounds exhibited distinct characteristics depending on the steric hindrance of the aldehyde employed. In instances where aromatic aldehydes were utilized, functionalization occurred at the methine group bridging both triazole rings. Conversely, the use of pivalic aldehyde prompted functionalization at the C5 position of the triazole ring. These compounds were subsequently employed as ligand precursors in the synthesis of organometallic aluminum and zinc complexes, yielding dinuclear complexes with high efficiency. The structural elucidation of all compounds was accomplished through spectroscopic methods and validated by X-ray crystallography. Preliminary catalytic investigations into the coupling reaction of cyclohexene oxide and CO2 revealed that aluminum and zinc complexes catalyzed the selective formation of polyether and polycarbonate materials, respectively.

2.
Inorg Chem ; 63(30): 13875-13885, 2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39011646

RESUMO

Novel alkyl zinc complexes supported by acetamidate/thioacetamidate heteroscorpionate ligands have been successfully synthesized and characterized. These complexes exhibited different coordination modes depending on the electronic and steric effects of the acetamidate/thioacetamidate moiety. Their catalytic activity has been tested toward the hydroelementation reactions of alkynyl alcohol/acid substrates, affording the corresponding enol ether/unsaturated lactone products under mild reaction conditions. Kinetic studies have been performed and confirmed that reactions are first-order in [catalyst] and zero-order in [alkynyl substrate]. DFT calculations supported a reaction mechanism through the formation of the catalytically active species, an alkoxide-zinc intermediate, by a protonolysis reaction of the Zn-alkyl bond with the alcohol group of the substrate. Based on the experimental and theoretical results, a catalytic cycle has been proposed.

3.
Int J Mol Sci ; 25(9)2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38732018

RESUMO

Hydroxytyrosol (HT) is a bioactive olive oil phenol with beneficial effects in a number of pathological situations. We have previously demonstrated that an HT-enriched diet could serve as a beneficial therapeutic approach to attenuate ischemic-stroke-associated damage in mice. Our exploratory pilot study examined this effect in humans. Particularly, a nutritional supplement containing 15 mg of HT/day was administered to patients 24 h after the onset of stroke, for 45 days. Biochemical and oxidative-stress-related parameters, blood pressure levels, serum proteome, and neurological and functional outcomes were evaluated at 45 and 90 days and compared to a control group. The main findings were that the daily administration of HT after stroke could: (i) favor the decrease in the percentage of glycated hemoglobin and diastolic blood pressure, (ii) control the increase in nitric oxide and exert a plausible protective effect in oxidative stress, (iii) modulate the evolution of the serum proteome and, particularly, the expression of apolipoproteins, and (iv) be beneficial for certain neurological and functional outcomes. Although a larger trial is necessary, this study suggests that HT could be a beneficial nutritional complement in the management of human stroke.


Assuntos
Suplementos Nutricionais , Estresse Oxidativo , Álcool Feniletílico , Acidente Vascular Cerebral , Humanos , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/farmacologia , Álcool Feniletílico/uso terapêutico , Masculino , Acidente Vascular Cerebral/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Feminino , Idoso , Projetos Piloto , Pessoa de Meia-Idade , Pressão Sanguínea/efeitos dos fármacos , Óxido Nítrico/metabolismo
4.
J Public Health Manag Pract ; 30(1): 89-98, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37350621

RESUMO

OBJECTIVE: To assess the impact of a multicomponent intervention in women with cervical dysplasia who were treated with loop electrosurgical excision procedure (LEEP), as well as the time between colposcopy and treatment. DESIGN: Retrospective cohort study. INTERVENTION: Clinic participation in a multicomponent cervical cancer prevention program that included community outreach, patient in-reach, and navigation, as well as provider capacity building with in-person training and ongoing telementoring through Project ECHO. MAIN OUTCOME MEASURES: Medical records were reviewed to evaluate women with cervical dysplasia undergoing treatment with LEEP within 90 days of colposcopy, as well as time between colposcopy and treatment. Baseline data from year 1 were compared with each subsequent year of implementation. Additional variables examined included patient's age, history of abnormal screening results, and percentage of families living below poverty line based on county of residence, parity, and clinic site. We performed logistic regression and multiple linear regression analyses to assess the programmatic impact in the outcomes of interest by year of program implementation. RESULTS: A total of 290 women were included in the study. The proportion of women undergoing treatment within 90 days of colposcopy increased from 76.2% at baseline to 91.3% in year 3 and 92.9% in year 4 of program implementation. The odds of undergoing treatment within 90 days were 5.11 times higher in year 4 of program implementation than at baseline. The mean time between colposcopy and LEEP decreased from 62 days at baseline to 45 days by year 4 of program implementation. CONCLUSIONS: Implementation of our multicomponent cervical cancer prevention program increased the proportion of women undergoing LEEP within 90 days of colposcopy and decreased the time between colposcopy and LEEP. This program has the potential to support cervical cancer prevention efforts and could be implemented in other low-resource settings.


Assuntos
Lesões Pré-Cancerosas , Displasia do Colo do Útero , Neoplasias do Colo do Útero , Gravidez , Feminino , Humanos , Neoplasias do Colo do Útero/cirurgia , Neoplasias do Colo do Útero/diagnóstico , Estudos Retrospectivos , Texas/epidemiologia , Eletrocirurgia/métodos , Displasia do Colo do Útero/patologia , Displasia do Colo do Útero/cirurgia , Lesões Pré-Cancerosas/cirurgia
5.
Biophys J ; 122(21): 4241-4253, 2023 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-37803828

RESUMO

Hydrodynamic flow in the spider duct induces conformational changes in dragline spider silk proteins (spidroins) and drives their assembly, but the underlying physical mechanisms are still elusive. Here we address this challenging multiscale problem with a complementary strategy of atomistic and coarse-grained molecular dynamics simulations with uniform flow. The conformational changes at the molecular level were analyzed for single-tethered spider silk peptides. Uniform flow leads to coiled-to-stretch transitions and pushes alanine residues into ß sheet and poly-proline II conformations. Coarse-grained simulations of the assembly process of multiple semi-flexible block copolymers using multi-particle collision dynamics reveal that the spidroins aggregate faster but into low-order assemblies when they are less extended. At medium-to-large peptide extensions (50%-80%), assembly slows down and becomes reversible with frequent association and dissociation events, whereas spidroin alignment increases and alanine repeats form ordered regions. Our work highlights the role of flow in guiding silk self-assembly into tough fibers by enhancing alignment and kinetic reversibility, a mechanism likely relevant also for other proteins whose function depends on hydrodynamic flow.


Assuntos
Fibroínas , Seda , Seda/química , Seda/metabolismo , Proteínas de Artrópodes/química , Fibroínas/química , Peptídeos , Alanina
6.
Prev Med ; 175: 107670, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37586609

RESUMO

Despite the favorable health impacts of preventive services use, young adults remain at a higher risk of not using these services compared with older adults. This study seeks to identify barriers to receiving recommended preventive services among Asian young adults compared to other racial/ethnic young adults. Using 2016-2018 National Health Interview Survey data, this study examined barriers to recommended preventive services among non-Hispanic (NH) Asian young adults aged 18-39 years compared with other racial/ethnic groups in the United States (Total = 25,430; NH Asians = 6.3%). General prevention included fasting blood sugar, cholesterol, blood pressure, and Human Immunodeficiency Virus checkups. We documented information on vaccinations for influenza, pneumonia, tetanus, hepatitis A/B, and female-specific preventive care measures. NH Asian young adults reported blood pressure checkups less often than NH Whites (72.88% vs. 79.92%, p < 0.001). NH Asian young adults were also less likely to report HIV testing than all other racial/ethnic groups (p < 0.001). After controlling for covariates, NH Whites (odds ratio [OR] = 2.00, 95% confidence interval [CI] = 1.60, 2.50), NH Blacks (OR = 1.55, 95% CI = 1.18, 2.02), and other races (OR = 2.40, 95% CI = 1.60, 3.58) were more likely to receive any preventive services than NH Asians. Among those receiving any preventive services, there were no differences between NH Asians and all other racial/ethnic groups in whether they reported receiving relatively more preventive services. Our findings demonstrate that the rates of certain recommended preventive services use were lower among NH Asian young adults. Targeted public health strategies are needed to increase the use of preventive healthcare for racial/ethnic minority young adults.

7.
Inorg Chem ; 62(37): 14833-14837, 2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37676111

RESUMO

The successful architecture of active catalytic species with enhanced efficiencies is critical for the optimal exploitation of sustainable resources in industrially demanded processes. In this work, we describe the preparation of novel helical heterobimetallic Al/Mg-based complexes of the type [AlMe2(pbpamd-)MgR{κ1-O-(OC4H8O)}] [R = Et (1a), tBu (2a)] as potential catalysts. The design was performed through the sequential addition of the Al fragment to the ligand, followed by the Mg platform, resulting in a planar π-C2N2(sp2)-Al/Mg bridging core between metals. The new heterobimetallic species have been unambiguously characterized by single-crystal X-ray analysis. NOESY, DOSY, and EXSY NMR studies as well as density functional theory calculations corroborate both a rearrangement in solution to scorpionate complexes containing an unprecedented apical carbanion with a direct σ-C(sp3)-Al covalent bond named [{Mg(R)(pbpamd-) Al(Me)2}] [R = Et (1b), tBu (2b)] and an interconversion equilibrium between both isomers. We verified their utility and high efficiency as catalysts in the well-controlled ring-opening polymerization of the biorenewable l- and rac-lactide (LA) at 23 °C, reaching a remarkable turnover frequency value close to 25000 h-1 for rac-LA at this temperature and exerting a significant level of heteroselectivity (Pr = 0.80). Very interestingly, the kinetics demonstrate apparent first-order with respect to the catalyst and LA, which supports a synergic intramolecular cooperation between centers with electronic modulation among them.

8.
Int J Mol Sci ; 25(1)2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38203638

RESUMO

Modulation of the allergic immune response through alternative therapies is a field of study that aims to address allergic reactions differently from traditional approaches. These therapies encompass the utilization of natural functional foods, which have been observed to exert an influence on the immune response, thus mitigating the severity of allergies. Indeed, some studies suggest that the incorporation of these nutraceuticals can regulate immune function, leading to a reduction in histamine release and subsequent alleviation of allergic symptoms. Moreover, certain herbs and dietary supplements, such as curcumin, are believed to possess anti-inflammatory properties, which may serve to moderate allergic responses. Although the results remain somewhat mixed and require further research, these alternative therapies exhibit the potential to impact the allergic immune response, thereby providing complementary options to conventional treatments. Therefore, in this review, we aim to provide an updated account of functional foods capable of modulating the immune response to allergies. In that sense, the review delves into functional foods sourced from plants (phytochemicals), animals, and marine algae. Emphasis is placed on their potential application in the treatment of allergic disorders. It also provides an overview of how these foods can be effectively utilized as functional foods. Additionally, it explores the molecular mechanisms and scientific validity of various bioactive natural compounds in the management of allergies.


Assuntos
Alimento Funcional , Hipersensibilidade , Animais , Hipersensibilidade/tratamento farmacológico , Suplementos Nutricionais , Liberação de Histamina , Imunidade
9.
Molecules ; 28(5)2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36903509

RESUMO

Extra virgin olive oil (EVOO) has proven to yield a better health outcome than other saturated fats widely used in the Western diet, including a distinct dysbiosis-preventive modulation of gut microbiota. Besides its high content in unsaturated fatty acids, EVOO also has an unsaponifiable polyphenol-enriched fraction that is lost when undergoing a depurative process that gives place to refined olive oil (ROO). Comparing the effects of both oils on the intestinal microbiota of mice can help us determine which benefits of EVOO are due to the unsaturated fatty acids, which remain the same in both, and which benefits are a consequence of its minority compounds, mainly polyphenols. In this work, we study these variations after only six weeks of diet, when physiological changes are not appreciated yet but intestinal microbial alterations can already be detected. Some of these bacterial deviations correlate in multiple regression models with ulterior physiological values, at twelve weeks of diet, including systolic blood pressure. Comparison between the EVOO and ROO diets reveals that some of these correlations can be explained by the type of fat that is present in the diet, while in other cases, such as the genus Desulfovibrio, can be better understood if the antimicrobial role of the virgin olive oil polyphenols is considered.


Assuntos
Microbioma Gastrointestinal , Síndrome Metabólica , Camundongos , Animais , Azeite de Oliva , Manteiga , Dieta , Polifenóis
10.
Am J Public Health ; 112(9): 1269-1272, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35862887

RESUMO

This quasi-experimental study (a community-based, physician-led human papillomavirus [HPV] education campaign and school-based vaccination program) followed 6481 students at eight Pharr-San Juan-Alamo Independent School District (Rio Grande Valley, Texas) middle schools between August 2016 and March 2021. We describe the successes and challenges experienced during the COVID-19 pandemic. HPV vaccine initiation and completion rates increased 1.29-fold and 1.47-fold, respectively, between June 2019 and March 2021. Between March 2020 and March 2021, 268 HPV vaccine doses were provided through 24 school-based interventions. Our program continued successes seen in increasing HPV vaccination rates and reducing possible HPV-associated cancers. (Am J Public Health. 2022;112(9):1269-1272. https://doi.org/10.2105/AJPH.2022.306970).


Assuntos
Alphapapillomavirus , COVID-19 , Infecções por Papillomavirus , Vacinas contra Papillomavirus , COVID-19/prevenção & controle , Humanos , Pandemias/prevenção & controle , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/uso terapêutico , Aceitação pelo Paciente de Cuidados de Saúde , Texas/epidemiologia , Vacinação
11.
Soc Psychiatry Psychiatr Epidemiol ; 57(3): 633-645, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35064280

RESUMO

BACKGROUND: Preliminary country-specific reports suggest that the COVID-19 pandemic has a negative impact on the mental health of the healthcare workforce. In this paper, we summarize the protocol of the COVID-19 HEalth caRe wOrkErS (HEROES) study, an ongoing, global initiative, aimed to describe and track longitudinal trajectories of mental health symptoms and disorders among health care workers at different phases of the pandemic across a wide range of countries in Latin America, Europe, Africa, Middle-East, and Asia. METHODS: Participants from various settings, including primary care clinics, hospitals, nursing homes, and mental health facilities, are being enrolled. In 26 countries, we are using a similar study design with harmonized measures to capture data on COVID-19 related exposures and variables of interest during two years of follow-up. Exposures include potential stressors related to working in healthcare during the COVID-19 pandemic, as well as sociodemographic and clinical factors. Primary outcomes of interest include mental health variables such as psychological distress, depressive symptoms, and posttraumatic stress disorders. Other domains of interest include potentially mediating or moderating influences such as workplace conditions, trust in the government, and the country's income level. RESULTS: As of August 2021, ~ 34,000 health workers have been recruited. A general characterization of the recruited samples by sociodemographic and workplace variables is presented. Most participating countries have identified several health facilities where they can identify denominators and attain acceptable response rates. Of the 26 countries, 22 are collecting data and 2 plan to start shortly. CONCLUSIONS: This is one of the most extensive global studies on the mental health of healthcare workers during the COVID-19 pandemic, including a variety of countries with diverse economic realities and different levels of severity of pandemic and management. Moreover, unlike most previous studies, we included workers (clinical and non-clinical staff) in a wide range of settings.


Assuntos
COVID-19 , Pandemias , COVID-19/epidemiologia , Pessoal de Saúde/psicologia , Humanos , Saúde Mental , SARS-CoV-2
12.
Small ; 17(3): e2006795, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33354900

RESUMO

Precise mechanical processing of optical microcrystals involves complex microscale operations viz. moving, bending, lifting, and cutting of crystals. Some of these mechanical operations can be implemented by applying mechanical force at specific points of the crystal to fabricate advanced crystalline optical junctions. Mechanically compliant flexible optical crystals are ideal candidates for the designing of such microoptical junctions. A vapor-phase growth of naturally bent optical waveguiding crystals of 1,4-bis(2-cyanophenylethynyl)benzene (1) on a surface forming different optical junctions is presented. In the solid-state, molecule 1 interacts with its neighbors via CH⋅⋅⋅N hydrogen bonding and π-π stacking. The microcrystals deposited at a glass surface exhibit moderate flexibility due to substantial surface adherence energy. The obtained network crystals also display mechanical compliance when cut precisely with sharp atomic force microscope cantilever tip, making them ideal candidates for building innovative T- and Δ-shaped optical junctions with multiple outputs. The presented micromechanical processing technique can also be effectively used as a tool to fabricate single-crystal integrated photonic devices and circuits on suitable substrates.

13.
Gynecol Oncol ; 160(1): 16-23, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33221024

RESUMO

OBJECTIVE: While disparities in endometrial hyperplasia and endometrial cancer are well documented in Blacks and Whites, limited information exists for Hispanics. The objective is to describe the patient characteristics associated with endometrial hyperplasia symptoms, endometrial hyperplasia with atypia and endometrial cancer, and assess factors contributing to racial/ethnic differences in disease outcomes. METHODS: This single-center, retrospective study included women aged ≥50 years with ≥ two encounters for endometrial hyperplasia symptoms, endometrial hyperplasia with atypia and endometrial cancer between 2012 and 2016. Multivariate logistic regression models evaluated the predictors of endometrial cancer and hyperplasia. RESULTS: We included 19,865 women (4749 endometrial hyperplasia symptoms, 71 endometrial hyperplasias with atypia, 201 endometrial cancers) with mean age of 60.45 years (SD 9.94). The odds of endometrial hyperplasia symptoms were higher in non-Hispanic Blacks (Odds Ratio [OR] 1.56, 95% Confidence Interval [CI] 1.20-1.72), Hispanics (OR 1.35, 95% CI 1.22-1.49), family history of female cancer (OR 1.25, 95% CI 1.12-1.39), hypertension (OR 1.24, 95% CI 1.14-1.35), and birth control use (OR 1.29, 95% CI 1.15-1.43). Odds of endometrial cancer and atypical hyperplasia increased for ages 60-64 (OR 7.95, 95% CI 3.26-19.37; OR 3.66, 95% 1.01-13.22) and being obese (OR 1.61, 95% CI 1.08-2.41; OR: 6.60, 95% CI 2.32-18.83). Odds of endometrial cancer increased with diabetes (OR 1.68, 95% CI 1.22-2.32). CONCLUSION(S): Patients with obesity and diabetes had increased odds of endometrial cancer and hyperplasia with atypia. Further study is needed to understand the exogenous estrogen effect contributing to the increased incidence among Hispanics.


Assuntos
Hiperplasia Endometrial/epidemiologia , Neoplasias do Endométrio/epidemiologia , Hispânico ou Latino/estatística & dados numéricos , Fatores Etários , Estudos de Coortes , Diabetes Mellitus/epidemiologia , Diabetes Mellitus/etnologia , Hiperplasia Endometrial/etnologia , Hiperplasia Endometrial/patologia , Neoplasias do Endométrio/etnologia , Neoplasias do Endométrio/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Obesidade/epidemiologia , Obesidade/etnologia , Estudos Retrospectivos , Texas/epidemiologia , População Branca/estatística & dados numéricos
14.
Inorg Chem ; 60(7): 5322-5332, 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33719419

RESUMO

Despite the great interest in zinc catalysis for hydroelementation reactions, the use of zinc complexes as catalysts for the hydroalkoxylation of alkynyl alcohols has not been reported to date. Scorpionate zinc complexes have been successfully designed as precatalysts for the hydroalkoxylation reaction of alkynyl alcohols under mild reaction conditions. Zinc amide complex 8 has been shown to be an excellent precatalyst for the highly selective intramolecular hydroalkoxylation process to yield the corresponding exocyclic enol ethers. Kinetic studies have been performed and confirmed that reactions are first-order in [catalyst] and zero-order in [alkynyl alcohol]. NMR spectroscopy and X-ray diffraction analysis provided evidence for the formation of an alkynyl zinc compound which has been shown to be a key intermediate in the hydroalkoxylation process. On the basis of the experimental results, a catalytic cycle is proposed.

15.
Cancer ; 126(8): 1656-1667, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32037524

RESUMO

BACKGROUND: Human papillomavirus (HPV)-related disease remains a significant source of morbidity and mortality, and this underscores the need to increase HPV vaccination to reduce the burden of the disease. The objective of this study was to examine the association between the number of HPV vaccine doses and the risk of histologically confirmed preinvasive cervical disease and high-grade cytology. METHODS: This retrospective matched cohort study used administrative data from Optum's Clinformatics DataMart Database to identify females aged 9 to 26 years who received 1 or more quadrivalent HPV vaccine doses between January 2006 and June 2015. Cases and controls were matched on region, age, sexually transmitted disease history, and pregnancy. All had a Papanicolaou test ≥1 year after the date of the matched case's final dose. Cox proportional hazards models were used to examine the association between the number of HPV vaccine doses and the incidence of preinvasive cervical disease and high-grade cytology. The Kaplan-Meier method was used to estimate the cumulative incidence rate at the 5-year follow-up. RESULTS: The study included 133,082 females (66,541 vaccinated and 66,541 unvaccinated) stratified by the number of HPV vaccine doses and the vaccine initiation age. Among those aged 15 to 19 years, the hazard ratio (HR) for high-grade cytology for the 3-dose group was 0.84 (95% confidence interval [CI], 0.73-0.97), whereas the HRs for histologically confirmed preinvasive cervical disease for 1, 2, and 3 doses were 0.64 (95% CI, 0.47-0.88), 0.72 (95% CI, 0.54-0.95), and 0.66 (95% CI, 0.55-0.80), respectively. CONCLUSIONS: The receipt of 1, 2, or 3 doses of an HPV vaccine by females aged 15 to 19 years was associated with a lower incidence of preinvasive cervical disease in comparison with unvaccinated females, and this supports the use of any HPV vaccination in reducing the burden of the disease.


Assuntos
Papillomaviridae/imunologia , Infecções por Papillomavirus/imunologia , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/administração & dosagem , Vacinas contra Papillomavirus/imunologia , Adolescente , Adulto , Criança , Gerenciamento de Dados , Feminino , Humanos , Estudos Retrospectivos , Estados Unidos , Neoplasias do Colo do Útero/imunologia , Neoplasias do Colo do Útero/prevenção & controle , Neoplasias do Colo do Útero/virologia , Vacinação/métodos , Adulto Jovem , Displasia do Colo do Útero/imunologia , Displasia do Colo do Útero/prevenção & controle , Displasia do Colo do Útero/virologia
16.
Inorg Chem ; 59(17): 12422-12430, 2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32811145

RESUMO

Two new derivatives of the bis(3,5-dimethylpyrazol-1-yl)methane modified by introduction of organosilyl groups on the central carbon atom, one of which bearing a chiral fragment, have been easily prepared. We verified the potential utility of these compounds through the reaction with [Zr(NMe2)4] for the preparation of novel zirconium complexes in which an ancillary bis(pyrazol-1-yl)methanide acts as a robust monoanionic tridentate scorpionate in a κ3-NNC chelating mode, forming strained four-membered heterometallacycles. These κ3-NNC-scorpionate zirconium amides were investigated as catalysts in combination with tetra-n-butylammonium bromide as cocatalyst for CO2 fixation into five-membered cyclic carbonate products. The study has led to the development of an efficient zirconium-based bicomponent system for the selective cycloaddition reaction of CO2 with epoxides. Kinetics investigations confirmed apparent first-order dependence on the catalyst and cocatalyst concentrations. In addition, this system displays very broad substrate scope, including mono- and disubstituted substrates, as well as the challenging biorenewable terpene derived limonene oxide, under mild and solvent-free conditions.

17.
Inorg Chem ; 59(12): 8412-8423, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32452688

RESUMO

Novel bimetallic zinc acetate complexes supported by heteroscorpionate ligands have been developed for the ring-opening copolymerization of cyclohexene oxide and CO2 and the terpolymerization of cyclohexene oxide, phthalic anhydride, and CO2. Heteroscorpionate ligands precursors L1-L3 were reacted with two equivalents of zinc acetate to afford the dinuclear zinc complexes [{Zn(κ3-bpzappe)}(µ-O2CCH3)3-{Zn(HO2CCH3)}] (1), [{Zn(κ3-bpzbdmape)}(µ-O2CCH3)3-{Zn(HO2CCH3)}] (2), and [{Zn(κ3-bpzbdeape)}(µ-O2CCH3)3{Zn(HO2CCH3)}] (3) in excellent yields. The molecular structure of these compounds was determined spectroscopically and confirmed by X-ray diffraction analysis. Zinc acetate complexes 1-3 were screened as catalysts for the copolymerization of cyclohexene oxide and CO2 to produce poly(cyclohexene)carbonate, and complex 3 was found to be the most active catalyst for this process in the absence of a cocatalyst. Furthermore, the terpolymerization of cyclohexene oxide, phthalic anhydride, and CO2 was studied using the combination of complex 3 and 4-dimethylaminopyridine as catalyst system yielding the corresponding polyester-polycarbonate materials.

18.
Int J Mol Sci ; 21(12)2020 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-32570702

RESUMO

E. faecalis is a commensal bacterium with specific strains involved in opportunistic and nosocomial infections. Therefore, it is important to know how the strains of this species are selected in the gut. In this study, fifteen E. faecalis strains, isolated over twelve weeks from the faeces of mice fed standard chow or one of three high fat diets enriched with extra virgin olive oil, refined olive oil or butter were subjected to a genetic "Multilocus Sequence Typing" study that revealed the presence of mainly two genotypes, ST9 and ST40, the latter one prevailing at the end of the research. A V3-V5 sequence comparison of the predominant ST40 strain (12B3-5) in a metagenomic study showed that this sequence was the only E. faecalis present in the mouse cohort after twelve weeks. The strain was subjected to a comparative proteomic study with a ST9 strain by 2D electrophoresis and mass spectrometry. After comparing the results with a E. faecalis database, unshared entries were compared and 12B3-5 showed higher antimicrobial production as well as greater protection from environmental factors such as xenobiotics, oxidative stress and metabolite accumulation, which could be the reason for its ability to outcompete other possible rivals in an intestinal niche.


Assuntos
Proteínas de Bactérias/metabolismo , Dieta Hiperlipídica/efeitos adversos , Enterococcus faecalis/classificação , Tipagem de Sequências Multilocus/métodos , Animais , Dieta Hiperlipídica/classificação , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/genética , Enterococcus faecalis/isolamento & purificação , Fezes/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Genótipo , Masculino , Camundongos , Prevalência , Proteômica
19.
Biophys J ; 116(9): 1579-1585, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-30975453

RESUMO

Flow at the molecular level induces shear-induced unfolding of single proteins and can drive their assembly, the mechanisms of which are not completely understood. To be able to analyze the role of flow on molecules, we present uniform-flow molecular dynamics simulations at atomic level. The pull module of the GRoningen MAchine for Chemical Simulations package was extended to be able to force-group atoms within a defined layer of the simulation box. Application of this external enforcement to explicit water molecules, together with the coupling to a thermostat, led to a uniform terminal velocity of the solvent water molecules. We monitored the density of the whole system to establish the conditions under which the simulated flow is well-behaved. A maximal velocity of 1.3 m/s can be generated if a pull slice of 8 nm is used, and high velocities would require larger pull slices to still maintain a stable density. As expected, the target velocity increases linearly with the total external force applied. Finally, we suggest an appropriate setup to stretch a protein by uniform flow, in which protein extensions depend on the flow conditions. Our implementation provides an efficient computational tool to investigate the effect of the flow at the molecular level.


Assuntos
Fenômenos Mecânicos , Simulação de Dinâmica Molecular , Hidrodinâmica , Água/química
20.
Gynecol Oncol ; 154(3): 558-564, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31288949

RESUMO

OBJECTIVE: Cervical cancer rates in the United States have declined since the 1940's, however, cervical cancer incidence remains elevated in medically-underserved areas, especially in the Rio Grande Valley (RGV) along the Texas-Mexico border. High-resolution microendoscopy (HRME) is a low-cost, in vivo imaging technique that can identify high-grade precancerous cervical lesions (CIN2+) at the point-of-care. The goal of this study was to evaluate the performance of HRME in medically-underserved areas in Texas, comparing results to a tertiary academic medical center. METHODS: HRME was evaluated in five different outpatient clinical settings, two in Houston and three in the RGV, with medical providers of varying skill and training. Colposcopy, followed by HRME imaging, was performed on eligible women. The sensitivity and specificity of traditional colposcopy and colposcopy followed by HRME to detect CIN2+ were compared and HRME image quality was evaluated. RESULTS: 174 women (227 cervical sites) were included in the final analysis, with 12% (11% of cervical sites) diagnosed with CIN2+ on histopathology. On a per-site basis, a colposcopic impression of low-grade precancer or greater had a sensitivity of 84% and a specificity of 45% to detect CIN2+. While there was no significant difference in sensitivity (76%, p = 0.62), the specificity when using HRME was significantly higher than that of traditional colposcopy (56%, p = 0.01). There was no significant difference in HRME image quality between clinical sites (p = 0.77) or medical providers (p = 0.33). CONCLUSIONS: HRME imaging increased the specificity for detecting CIN2+ when compared to traditional colposcopy. HRME image quality remained consistent across different clinical settings.


Assuntos
Colonoscopia/economia , Colonoscopia/métodos , Área Carente de Assistência Médica , Lesões Pré-Cancerosas/diagnóstico por imagem , Neoplasias do Colo do Útero/diagnóstico por imagem , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Gradação de Tumores , Lesões Pré-Cancerosas/economia , Estudos Prospectivos , Sensibilidade e Especificidade , Texas , Estados Unidos , Neoplasias do Colo do Útero/patologia , Displasia do Colo do Útero/diagnóstico por imagem , Displasia do Colo do Útero/economia
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