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1.
Climacteric ; 27(1): 93-103, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37933495

RESUMO

This systematic review assesses the effect of menopausal hormone therapy (MHT) on cardiovascular outcomes and risk factors in postmenopausal women with cardiovascular disease (CVD). The Medline, Embase and Cochrane databases were searched from inception to December 2022 for randomized controlled trials (RCTs) and observational studies using methodology from a previous Cochrane review. Quality assessment used the Cochrane risk of bias tool and Newcastle-Ottawa scale, respectively. From 5647 studies identified, 29 (23 RCTs and six observational studies) were included. Most studies were conducted in North America or Europe and investigated oral estrogens. Participants were older with varying frequency of cardiac risk factors and underlying CVD. No significant difference was observed between MHT users and controls regarding primary outcomes of non-fatal myocardial infarction, cardiovascular death or stroke. No difference in frequency of angina, heart failure and transient ischemic attacks was observed. Inconsistent effects of MHT on angiographic progression were seen and varied with glycemic status. Estradiol had a positive effect on flow-mediated dilatation. Limited studies identified differing effects of MHT on cardiac risk factors, varying with estrogen preparation. This study confirms no benefit of MHT for secondary CVD prevention, highlighting evidence limitations and the importance of shared decision-making when managing menopausal symptoms in women with CVD.


Assuntos
Doenças Cardiovasculares , Feminino , Humanos , Doenças Cardiovasculares/prevenção & controle , Terapia de Reposição de Estrogênios/efeitos adversos , Terapia de Reposição de Estrogênios/métodos , Menopausa , Estrogênios/uso terapêutico , Estrogênios/farmacologia , Estradiol/uso terapêutico , Estradiol/farmacologia
2.
Phys Rev Lett ; 129(16): 162701, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36306775

RESUMO

We have performed the first direct measurement of two resonances of the ^{7}Be(α,γ)^{11}C reaction with unknown strengths using an intense radioactive ^{7}Be beam and the DRAGON recoil separator. We report on the first measurement of the 1155 and 1110 keV resonance strengths of 1.73±0.25(stat)±0.40(syst) eV and 125_{-25}^{+27}(stat)±15(syst) meV, respectively. The present results have reduced the uncertainty in the ^{7}Be(α,γ)^{11}C reaction rate to ∼9.4%-10.7% over T=1.5-3 GK, which is relevant for nucleosynthesis in the neutrino-driven outflows of core-collapse supernovae (νp process). We find no effect of the new, constrained reaction rate on νp-process nucleosynthesis.

3.
Med Chem Res ; 31(7): 1154-1175, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36389181

RESUMO

Compound VBT-5445 was identified as an inhibitor to block the association of Pim and the protein Enhancer of Decapping 3 (EDC3), a Pim substrate, which normally functions to enhance the decapping of messenger RNA (mRNA). It was also shown to inhibit both the Pim and mTORC protein kinases. The activity of this compound class can be fine-tuned by structural modification. A series of VBT analogs were designed, synthesized, and evaluated. These compounds decrease the growth of multiple cancer types, including pancreas, prostate, breast, lung, and leukemia. Notably, 6-methyl (GRG-1-31, 6d), 4-Bromo (GRG-1-34, 6e), 4-Chloro (GRG-1-35, 6f), and phenylthio substituted (GRG-1-104, 6n) derivatives are highly potent at inhibiting tumor growth. The ability of these compounds to block cancer growth in vitro is highly correlated with their activity as mTORC inhibitors. The toxicity of GRG 1-34 is low in mice treated with twice-daily gavage for 30 days and did not induce weight loss. Pharmacokinetics of a single oral dose demonstrated a peak concentration at 0.5 hours after gavage. In summary, further development of this compound class has the potential to inhibit important signaling pathways and impact cancer treatment.

4.
Lett Appl Microbiol ; 71(6): 637-644, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32785942

RESUMO

Widespread of heavy metals contamination has led to several environmental problems. Some biological methods to remove heavy metals from contaminated wastewater are being widely explored. In the present study, the efficiency of a white-rot fungus, Phlebia brevispora to remove different metals (Pb, Cd and Ni) has been evaluated. Atomic absorption spectroscopy of treated and untreated metal containing water revealed that all the metals were efficiently removed by the fungus. Among all the used metals, cadmium was the most toxic metal for fungal growth. Phlebia brevispora removed maximum Pb (97·5%) from 100 mmol l-1 Pb solution, which was closely followed by Cd (91·6%) and Ni (72·7%). Scanning electron microscopic images revealed that the presence of metal altered the morphology and fine texture of fungal hyphae. However, the attachment of metal on mycelia surface was not observed during energy-dispersive X-ray analysis, which points towards the intracellular compartmentation of metals in vacuoles. Thus, the study demonstrated an application of P. brevispora for efficient removal of Pb, Cd and Ni from the metal contaminated water, which can further be applied for bioremediation of heavy metals present in the industrial effluent.


Assuntos
Cádmio/metabolismo , Chumbo/metabolismo , Níquel/metabolismo , Polyporales/metabolismo , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Biodegradação Ambiental , Metais Pesados/metabolismo , Águas Residuárias/análise
5.
Public Health ; 179: 68-75, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31733509

RESUMO

OBJECTIVES: For population-level screening of malnutrition among adults-especially in developing-country settings-the body mass index (BMI) can be impractical because of logistical requirements for weight and height measurement. We analyzed anthropometric data collected from a large-scale nutritional survey on women of rural Bihar to determine the mid-upper arm circumference (MUAC) cutoffs corresponding to standard BMI cutoffs and the predictive accuracies of the determined cutoffs. STUDY DESIGN: It was a cross-sectional study using multistage cluster sampling. METHODS: The current analysis used anthropometric data from a study on dietary practices of rural women (adolescents, lactating mothers, and women in the interpregnancy period). The MUAC (cm) cutoffs corresponding to four standard BMI (kg/m2) values were determined using receiver operating characteristic (ROC) curve analysis. RESULT: We detected a significant positive correlation between BMI and MUAC (r = 0.81, P < 0.0001). In ROC curve analysis, the MUAC cutoffs corresponding to BMI cutoffs of 18.5, 23, 25, and 30 kg/m2 were estimated to be 23.2, 26.0, 27.3, and 30.5 kg/m2, respectively. The predictive accuracy of the determined cutoffs was good, as indicated by the area under the ROC curve for the four different cutoffs-which ranged between 88% and 97%. Other than the cutoff for 'obese' (BMI, 30 kg/m2), the Kappa coefficients for the rest of the MUAC cutoffs showed 'substantial' agreement (>0.6) with their BMI counterparts. CONCLUSION: The results suggest that the cutoffs based on MUAC-a less resource-intensive measure than BMI-can be used for community-based screening of malnutrition among women of Bihar.


Assuntos
Antropometria/métodos , Braço/anatomia & histologia , Povo Asiático/estatística & dados numéricos , Estado Nutricional , Adolescente , Adulto , Braço/fisiologia , Índice de Massa Corporal , Peso Corporal , Estudos Transversais , Feminino , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Obesidade , População Rural , Sensibilidade e Especificidade
6.
J Biol Chem ; 293(8): 2755-2769, 2018 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-29301937

RESUMO

An increasing prevalence of cases of drug-resistant tuberculosis requires the development of more efficacious chemotherapies. We previously reported the discovery of a new class of cyclipostins and cyclophostin (CyC) analogs exhibiting potent activity against Mycobacterium tuberculosis both in vitro and in infected macrophages. Competitive labeling/enrichment assays combined with MS have identified several serine or cysteine enzymes in lipid and cell wall metabolism as putative targets of these CyC compounds. These targets included members of the antigen 85 (Ag85) complex (i.e. Ag85A, Ag85B, and Ag85C), responsible for biosynthesis of trehalose dimycolate and mycolylation of arabinogalactan. Herein, we used biochemical and structural approaches to validate the Ag85 complex as a pharmacological target of the CyC analogs. We found that CyC7ß, CyC8ß, and CyC17 bind covalently to the catalytic Ser124 residue in Ag85C; inhibit mycolyltransferase activity (i.e. the transfer of a fatty acid molecule onto trehalose); and reduce triacylglycerol synthase activity, a property previously attributed to Ag85A. Supporting these results, an X-ray structure of Ag85C in complex with CyC8ß disclosed that this inhibitor occupies Ag85C's substrate-binding pocket. Importantly, metabolic labeling of M. tuberculosis cultures revealed that the CyC compounds impair both trehalose dimycolate synthesis and mycolylation of arabinogalactan. Overall, our study provides compelling evidence that CyC analogs can inhibit the activity of the Ag85 complex in vitro and in mycobacteria, opening the door to a new strategy for inhibiting Ag85. The high-resolution crystal structure obtained will further guide the rational optimization of new CyC scaffolds with greater specificity and potency against M. tuberculosis.


Assuntos
Aciltransferases/antagonistas & inibidores , Antituberculosos/farmacologia , Inibidores Enzimáticos/farmacologia , Modelos Moleculares , Mycobacterium tuberculosis/efeitos dos fármacos , Compostos Organofosforados/farmacologia , Acilação/efeitos dos fármacos , Aciltransferases/genética , Aciltransferases/metabolismo , Substituição de Aminoácidos , Antígenos de Bactérias/genética , Antígenos de Bactérias/metabolismo , Antituberculosos/química , Antituberculosos/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Domínio Catalítico , Cristalografia por Raios X , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Ligantes , Viabilidade Microbiana/efeitos dos fármacos , Conformação Molecular , Mutação , Mycobacterium tuberculosis/citologia , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/metabolismo , Compostos Organofosforados/química , Compostos Organofosforados/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Serina/química
7.
Langmuir ; 33(5): 1295-1304, 2017 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-28092704

RESUMO

Ionic liquids (ILs) are important for their antimicrobial activity and are found to be toxic to some microorganisms. To shed light on the mechanism of their activities, the interaction of an imidazolium-based IL 1-butyl-3-methylimidazolium tetrfluoroborate ([BMIM][BF4]) with E. coli bacteria and cell-membrane-mimicking lipid mono- and bilayers has been studied. The survival of the bacteria and corresponding growth inhibition are observed to be functions of the concentration of the IL. The IL alters the pressure-area isotherm of the monolayer formed at an air-water interface by the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid. The in-plane elasticity of the lipid layer is reduced as a consequence of the insertion of this IL. The X-ray reflectivity study from a polymer-supported lipid bilayer shows strong perturbation in the self-assembled structure of the bilayer due to the interaction. As a consequence, there is a considerable decrease in bilayer thickness and a corresponding increase in electron density. These results, however, depend on the chain configurations of the lipid molecules.


Assuntos
Boratos/química , Membrana Celular/química , Escherichia coli/química , Imidazóis/química , Líquidos Iônicos/química , Bicamadas Lipídicas/química , Boratos/farmacologia , Relação Dose-Resposta a Droga , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Imidazóis/farmacologia , Líquidos Iônicos/farmacologia , Estrutura Molecular , Raios X
8.
J Clin Microbiol ; 52(12): 4432-4, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25297331

RESUMO

We report three cases of infection due to the Gram-negative rod Ignatzschineria (Schineria) indica involving bacteremia and the urinary tract. Two cases were clearly associated with maggot infestation, and the third could conceivably have had unrecognized maggot infestation of the urinary tract. We believe these cases to be the first I. indica infections reported in association with maggot infestation and myiasis.


Assuntos
Infecções por Bactérias Gram-Negativas/diagnóstico , Infecções por Bactérias Gram-Negativas/microbiologia , Miíase/complicações , Xanthomonadaceae/classificação , Xanthomonadaceae/isolamento & purificação , Adulto , Idoso , Bacteriemia/diagnóstico , Bacteriemia/microbiologia , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Humanos , Masculino , Pessoa de Meia-Idade , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Infecções Urinárias/diagnóstico , Infecções Urinárias/microbiologia , Xanthomonadaceae/genética
9.
Phys Rev Lett ; 111(8): 087603, 2013 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-24010477

RESUMO

We report on the nondestructive measurement of nuclear magnetization in n-GaAs via cavity enhanced Faraday rotation. In contrast with the existing optical methods, this detection scheme does not require the presence of detrimental out-of-equilibrium electrons. Specific mechanisms of the Faraday rotation are identified for (i) nuclear spins situated within the localized electron orbits, these spins are characterized by fast dynamics, (ii) all other nuclear spins in the sample characterized by much slower dynamics. Our results suggest that even in degenerate semiconductors nuclear spin relaxation is limited by the presence of localized electron states and spin diffusion, rather than by Korringa mechanism.

10.
In Silico Pharmacol ; 10(1): 2, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34926126

RESUMO

One of the primary cancer treatment modalities is chemotherapy. Unfortunately, traditional anti-cancer drugs are often not selective and cause damage to healthy cells, leading to serious side effects for patients. For this reason more targeted therapeutics and drug delivery methods are being developed. The effectiveness of new treatments is initially determined via in vitro cell viability assays, which determine the IC 50  of the drug. However, these assays are known to result in estimates of IC 50  that depend on the measurement time, possibly resulting in over- or under-estimation of the IC 50 . Here, we test the possibility of using cell growth curves and fitting of mathematical models to determine the IC 50  as well as the maximum efficacy of a drug ( ε max ). We measured cell growth of MCF-7 and HeLa cells in the presence of different concentrations of doxorubicin and fit the data with a logistic growth model that incorporates the effect of the drug. This method leads to measurement time-independent estimates of IC 50  and ε max , but we find that ε max  is not identifiable. Further refinement of this methodology is needed to produce uniquely identifiable parameter estimates.

11.
Water Sci Technol ; 63(2): 276-82, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21252431

RESUMO

Perfluorooctanoic acid (PFOA) is very persistent in the environment and widely detected in the water environment. Only some advanced methods with extreme reaction conditions are shown to be capable of degrading the compound efficiently, and almost all the earlier investigations used very high PFOA concentrations. The compound is detected normally at very low concentrations in the water environment, while mild reaction conditions for its degradation are preferable. This article aimed to elucidate photodegradation of PFOA in dilute aqueous solutions by combined UV wavelengths (185 nm+254 nm) and 254 nm using a newly designed UV jacket. PFOA degradation was greatly enhanced with the combined wavelengths with almost one hundred percent PFOA removals in four-hour reaction. The removals were well described by the first-order reaction kinetic. The removal efficiencies and rate values significantly decreased with smaller initial PFOA concentrations. But defluorination was greatly enhanced with smaller PFOA concentrations possibly due to accelerated decomposition of fluorinated intermediates of PFOA. Formic acid and acetic acid were two tentatively identified intermediates of PFOA photolysis while the former was a major intermediate predominantly controlling solution pH during the oxidation. The results demonstrated that PFOA photolysis by the combined wavelengths with mild reaction conditions can be greatly enhanced by proper design of UV jacket and reactor system.


Assuntos
Caprilatos/efeitos da radiação , Fluorocarbonos/efeitos da radiação , Fotólise/efeitos da radiação , Raios Ultravioleta , Água/química , Ácidos Carboxílicos/análise , Cromatografia por Troca Iônica , Fluoretos/análise , Meia-Vida , Halogenação/efeitos da radiação , Concentração de Íons de Hidrogênio/efeitos da radiação , Cinética , Soluções
12.
Water Sci Technol ; 64(10): 1980-6, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22105118

RESUMO

The widespread detection of perfluorinated compounds (PFCs) in the water environment has been a concern for the last several years, while effluents from wastewater treatment facilities are the major sources of these compounds. Even advanced oxidation technologies (AOTs) are not useful for mineralization of the compounds due to their very high stability. Photochemical techniques using particularly vacuum UV (VUV) have been found to be very promising in this regard. But the use of VUV in UV-based AOTs has still not progressed much. Moreover, the impact of water quality on PFCs photomineralization is unknown. This investigation aimed to assess photomineralization potentials of perfluorooctanoic acid (PFOA) in ultrapure water (UPW), tap water (TW), surface water and treated wastewater effluent using a reactor setup enabling maximum utilization of VUV emission of low pressure lamp in laboratory batch experiments. Neya River water (NRW) and the Nakahama Wastewater Treatment Plant Effluent (NWWTPE) represented surface water and treated wastewater effluent respectively. Also, tests were carried out in 50% diluted NRW and NWWTPE. PFOA photomineralization in terms of PFOA removal, defluorination and total organic carbon (TOC) removal are discussed. The usefulness of the method for PFOA mineralization in organic-rich wastewaters, and further research needs are also highlighted.


Assuntos
Caprilatos/análise , Fluorocarbonos/análise , Raios Ultravioleta , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Qualidade da Água/normas , Japão , Fotólise
13.
Sci Total Environ ; 793: 148518, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34171804

RESUMO

Ozone plays an important role in the thermal structure and chemical composition of the atmosphere. The present study compares the temporal and spatial distributions of Total Column Ozone (TCO) over the Indian sub-continent retrieved from a geostationary Indian National Satellite (INSAT-3D) and Atmospheric Infrared Sounder (AIRS). The INSAT-3D TCO values are also evaluated against the Dobson spectrophotometer observations at two locations. The inter-comparison results reveal a good correlation of 0.8, the bias of -5 DU, and Root Mean Square Error (RMSE) of 15 DU approximately between the TCO retrieved from INSAT-3D and AIRS. The lowest RMSE and highest correlation coefficient were found in the pre-monsoon season. The INSAT-3D and AIRS show reasonable agreement with the RMSE varying between 10 and 30 DU. On the other hand, evaluation of the INSAT-3D TCO with the ground-based observations from Dobson spectrophotometers located at New Delhi and Varanasi showed fair agreement with a maximum monthly mean correlation coefficient of 0.68 and 0.76, respectively, and RMSE varying from 11 to 16 DU for both the stations. The seasonal distribution of TCO and its variation over the Indian region has also been studied using INSAT-3D and AIRS data. The analysis exhibits strong seasonal variations, with higher values in pre-monsoon season and minimum values in winter season. The noticeable seasonal variability of TCO can be attributed to complex combination of photochemical and dynamical processes in the troposphere and stratosphere. The main objectives of the study are to compare the INSAT-3D TCO with two independent ground-based Dobson spectrophotometer observations and Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite.


Assuntos
Poluentes Atmosféricos , Ozônio , Poluentes Atmosféricos/análise , Atmosfera , Monitoramento Ambiental , Índia , Ozônio/análise
14.
Water Sci Technol ; 62(3): 484-90, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20705994

RESUMO

Presence of chlorinated organic compounds in water bodies has become a concern among governments, health authorities and general public. Oxidation of organic compounds in water under high temperature and pressure is considered as a promising technique, but usefulness of the technique to mineralize 2,4-dichlorophenoxyacetic acid (2,4-D) is not well understood. This article aimed to elucidate degradation characteristics of 2,4-D in both subcritical and supercritical waters by laboratory batch experiments. 2,4-D degradation, total organic carbon (TOC) removal and dechlorination increased with increasing reaction time and temperature especially in subcritical waters, while dechlorination was a major step. 2,4-dichlorophenol (2,4-DCP) and acetic acid were the main degradation intermediates both in subcritical and supercritical waters. Though 2,4-D disappeared almost completely in subcritical waters near critical region ( approximately 99%), significant amounts of TOC and organic chlorine still remained as 2,4-DCP and acetic acid. But TOC removal and dechlorination were significantly enhanced ( approximately 95 and 91% respectively) in supercritical waters. Complete mineralization of 2,4-D in subcritical waters required a considerably longer reaction period, while the mineralization was almost complete within a short reaction period in supercritical waters. This is an important information of practical significance for oxidative degradation of chlorinated pesticides similar to 2,4-D.


Assuntos
Ácido 2,4-Diclorofenoxiacético/química , Herbicidas/química , Poluentes Químicos da Água/química , Água/química , Oxirredução , Pressão , Temperatura , Purificação da Água
15.
Sci Rep ; 10(1): 12955, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737428

RESUMO

Large rivers, including the Murray River system in southeast Australia, are disturbed by many activities. The arrival of European settlers to Australia by the mid-1800s transformed many floodplain wetlands of the lower Murray River system. River impoundment and flow regulation in the late 1800s and, from the 1930s, resulted in species invasion, and elevated nutrient concentrations causing widespread eutrophication. An integrated palaeoecology, and palaeo-and-modern food web approach, incorporating mixing models, was undertaken to reveal changes in a regulated wetland (i.e. Kings Billabong). The lack of preserved sediment suggests the wetland was naturally intermittent before 1890. After this time, when used as a water retention basin, the wetland experienced net sediment accumulation. Subfossil cladocerans, and δ13C of Daphnia, chironomid, and bulk sediment, all reflected an early productive, likely clear water state and shifts in trophic state following river regulation in the 1930s. Food web mixing models, based on δ13C and δ15N in subfossil and modern Daphnia, fish, and submerged and emergent macrophytes, also indicated a shift in the trophic relationships between fish and Daphnia. By the 1970s, a new state was established but a further significant alteration of nitrogen and carbon sources, and trophic interactions, continued through to the early 2000s. A possible switch from Daphnia as a prey of Australian Smelt could have modified the food web of the wetland by c. 2006. The timing of this change corresponded to the expansion of emergent macrophytes possibly due to landscape level disruptions. The evidence of these changes suggests a need for a broader understanding of the evolution of wetlands for the management of floodplains in the region.


Assuntos
Daphnia/fisiologia , Cadeia Alimentar , Modelos Biológicos , Rios , Áreas Alagadas , Animais , Austrália
16.
Biochemistry ; 48(22): 4972-9, 2009 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-19371093

RESUMO

The activity of tyrosine hydroxylase is regulated by reversible phosphorylation of serine residues in an N-terminal regulatory domain and catecholamine inhibition at the active site. Catecholamines such as dopamine bind very tightly to the resting enzyme; phosphorylation of Ser40 decreases the affinity for catecholamines by 3 orders of magnitude. The effects of dopamine binding and phosphorylation of Ser40 on the kinetics of deuterium incorporation into peptide bonds were examined by mass spectrometry. When dopamine is bound, three peptic peptides show significantly slower deuterium incorporation, 35-41 and 42-71 in the regulatory domain and 295-299 in the catalytic domain. In the phosphorylated enzyme, peptide 295-299 shows more rapid incorporation of deuterium, while 35-41 and 42-71 can not be detected. These results are consistent with tyrosine hydroxylase existing in two different conformations. In the closed conformation, the regulatory domain lies across the active site loop containing residues 295-298; this is stabilized when dopamine is bound in the active site. In the open conformation, the regulatory domain has moved out of the active site, allowing substrate access; this conformation is favored by phosphorylation of Ser40.


Assuntos
Medição da Troca de Deutério , Deutério/química , Hidrogênio/química , Tirosina 3-Mono-Oxigenase/química , Tirosina 3-Mono-Oxigenase/metabolismo , Animais , Domínio Catalítico , Catecolaminas/metabolismo , Bovinos , Medição da Troca de Deutério/métodos , Dopamina/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Fosforilação , Ligação Proteica , Ratos , Serina/química , Serina/metabolismo
17.
ACS Appl Mater Interfaces ; 11(27): 24412-24422, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31199615

RESUMO

Sensing of a few unpaired electron spins, such as in metal ions and radicals, is a useful but difficult task in nanoscale physics, biology, and chemistry. Single negatively charged nitrogen-vacancy (NV-) centers in diamond offer high sensitivity and spatial resolution in the optical detection of weak magnetic fields produced by a spin bath but often require long acquisition times on the order of seconds. Here, we present an approach based on coupled spin and charge dynamics in dense NV ensembles in strongly fluorescent nanodiamonds (NDs) to sense external magnetic dipoles. We apply this approach to various paramagnetic species, including gadolinium complexes, magnetite nanoparticles, and hemoglobin in whole blood. Taking advantage of the high NV density, we demonstrate a dramatic reduction in acquisition time (down to tens of milliseconds) while maintaining high sensitivity to paramagnetic centers. Strong luminescence, high sensitivity, and short acquisition time make dense NV- ensembles in NDs a potentially promising tool for biosensing and bioimaging applications.

18.
J Am Soc Mass Spectrom ; 30(11): 2306-2317, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31399941

RESUMO

We investigate the gas-phase structures and fragmentation pathways of model compounds of anthracene derivatives of the general formula CcHhN1 utilizing tandem mass spectrometry and computational methods. We vary the substituent alkyl chain length, composition, and degree of branching. We find substantial experimental and theoretical differences between the linear and branched congeners in terms of fragmentation thresholds, available pathways, and distribution of products. Our calculations predict that the linear substituents initially isomerize to form lower energy branched isomers prior to loss of the alkyl substituents as alkenes. The rate-determining chemistry underlying these related processes is dominated by the ability to stabilize the alkene loss transition structures. This task is more effectively undertaken by branched substituents. Consequently, analyte lability systematically increased with degree of branching (linear < secondary < tertiary). The resulting anthracen-9-ylmethaniminium ion generated from these alkene loss reactions undergoes rate-limiting proton transfer to enable expulsion of either hydrogen cyanide or CNH. The combination of the differences in primary fragmentation thresholds and degree of radical-based fragmentation processes provide a potential means of distinguishing compounds that contain branched alkyl chain substituents from those with linear ones.

19.
Water Sci Technol ; 58(1): 207-16, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18653956

RESUMO

Photocatalytic ozonation (O(3)/UV/TiO2) is an emerging oxidation method for recalcitrant organic contaminants in water. However, immobilised TiO2 catalysts suffer from reduced photonic efficiency. Therefore, TiO2 catalysts with excellent mechanical and thermal properties and enhanced photonic efficiencies are sought. This paper aimed to elucidate the mineralisation of low concentration 2,4-D (45.0 microM) by O(3)/UV/TiO2 using the world's first high-strength TiO2 fibre in laboratory batch experiments. 2,4-D degradation and TOC removal followed pseudo first-order reaction kinetic. The removal rates for 2,4-D and TOC in O(3)/UV/TiO2 were 1.5 and 2.4-fold larger than the summation of the values for ozonation (O3)) and photocatalysis (UV/TiO2), respectively. O(3)/UV/TiO2 was characterised by few aromatic intermediates with low abundance, fast degradations of aliphatic intermediates and dechlorination as a major step. The significantly enhanced 2,4-D mineralisation in O(3)/UV/TiO2 was attributed to increased ozone dissolution and decomposition, and reduced electron-hole recombination resulting in large number of hydroxyl radical (*OH) formation from more than one parallel path. The discrepancies in the organic carbon mass budget were attributed to few apparently major unidentified intermediates, while chlorine mass balance was reasonably acceptable. The mineralisation efficiency of O(3)/UV/TiO2 with the TiO2 fibre can further be enhanced by optimisation of experimental design parameters. The new TiO2 fibre is very promising to overcome the problem of reduced efficiency of TiO2 catalyst in an immobilised state.


Assuntos
Ozônio , Titânio/química , Ácido 2,4-Diclorofenoxiacético/isolamento & purificação , Catálise , Cinética , Oxirredução , Fotoquímica , Soluções , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos
20.
Water Sci Technol ; 58(1): 73-81, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18653939

RESUMO

This paper aims to elucidate retention characteristics of some pharmaceuticals and personal care products (PPCPs), and endocrine disrupting chemicals (EDCs), by two polyamide low pressure reverse osmosis (LPRO) membranes. Feed solution pH did not have an influence on rejections of undissociated solutes, which was most likely governed by adsorption, size exclusion and diffusion simultaneously. Size exclusion was presumably dominant, especially with tight membranes (UTC-70U). Rejections of the solutes with low dipole moment (<1.0 debye) decreased with increasing octanol-water partition coefficient (K(ow)). The solutes with large K(ow) values were most likely adsorbed on membrane and subsequently passed through it resulting in larger diffusion coefficient (D(p)). The rejections decreased with increasing D(p) values irrespective of their dipole moments. Rejections of solutes with comparatively larger dipole moments might be dominated by diffusion and/or convection rather than their hydrophobicity. However, rejections of solutes with hydroxyl and carboxyl functional groups by UTC-60 increased with solution pH. More than 80% rejections were obtained for degree of dissociation (alpha)>0.5. Electrostatic repulsion played a key role for rejection of dissociated solutes, especially by loose LPRO membranes. Therefore, assessing the dissociation degree at desired pH values can be a key step to obtain an insight of rejection mechanisms by polyamide membranes.


Assuntos
Disruptores Endócrinos/isolamento & purificação , Preparações Farmacêuticas/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Adsorção , Cromatografia em Gel , Desenho de Equipamento , Produtos Domésticos/análise , Humanos , Concentração de Íons de Hidrogênio , Potenciais da Membrana , Osmose , Ultrafiltração/métodos , População Urbana , Eliminação de Resíduos Líquidos/instrumentação , Poluentes Químicos da Água/isolamento & purificação , Abastecimento de Água/normas
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