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Advancing wet peatland 'paludiculture' innovation present enormous potential to sustain carbon-cycles, reduce greenhouse-gas (GHG) gas emissions and to transition communities to low-carbon economies; however, there is limited scientific-evidence to support and enable direct commercial viability of eco-friendly products and services. This timely study reports on a novel, paludiculture-based, integrated-multi-trophic-aquaculture (IMTA) system for sustainable food production in the Irish midlands. This freshwater IMTA process relies on a naturally occurring ecosystem of microalgae, bacteria and duckweed in ponds for managing waste and water quality that is powered by wind turbines; however, as it is recirculating, it does not rely upon end-of-pipe solutions and does not discharge effluent to receiving waters. This constitutes the first report on the effects of extreme weather events on the performance of this IMTA system that produces European perch (Perca fluviatilis), rainbow trout (Oncorhynchus mykiis) during Spring 2020. Sampling coincided with lockdown periods of worker mobility restriction due to COVID-19 pandemic. Observations revealed that the frequency and intensity of storms generated high levels of rainfall that disrupted the algal and bacterial ecosystem in the IMTA leading to the emergence and predominance of toxic cyanobacteria that caused fish mortality. There is a pressing need for international agreement on standardized set of environmental indicators to advance paludiculture innovation that addresses climate-change and sustainability. This study describes important technical parameters for advancing freshwater aquaculture (IMTA), which can be future refined using real-time monitoring-tools at farm level to inform management decision-making based on evaluating environmental indicators and weather data. The relevance of these findings to informing global sustaining and disruptive research and innovation in paludiculture is presented, along with alignment with UN Sustainable Development goals. This study also addresses global challenges and opportunities highlighting a commensurate need for international agreement on resilient indicators encompassing linked ecological, societal, cultural, economic and cultural domains.
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Aquicultura , Clima , Percas , Animais , COVID-19 , Controle de Doenças Transmissíveis , Meio Ambiente , Humanos , Pandemias , Áreas AlagadasRESUMO
On the 23 March 2020, a country-wide COVID-19 lockdown was imposed on the UK. The following 100 days saw anthropogenic movements quickly halt, before slowly easing back to a "new" normality. In this short communication, we use data from official UK air-quality sensors (DEFRA AURN) and the UK Met Office stations to show how lockdown measures affected air quality in the UK. We compare the 100 days post-lockdown (23 March to 30 June 2020) with the same period from the previous 7 years. We find, as shown in numerous studies of other countries, the nitrogen oxides levels across the country dropped substantially (â¼ 50%). However, we also find the ozone levels increased (â¼ 10%), and the levels of sulphur dioxide more than doubled across the country. These changes, driven by a complex balance in the air chemistry near the surface, may reflect the influence of low humidity as suggested by Met Office data, and potentially, the reduction of nitrogen oxides and their interactions with multiple pollutants.
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INTRODUCTION: Vitamin D catabolizing enzymes, along with vitamin D receptor (VDR) and vitamin D binding protein (DBP) are expressed in the decidua and placenta during pregnancy and capable of synthesizing active vitamin D. Vitamin D plays roles in immunoregulation and trophoblast invasion, key features of a successful pregnancy. Epidemiological data suggests that vitamin D deficiency is associated with both spontaneous and recurrent miscarriage but few studies have investigated the expression of the key vitamin D catabolizing enzymes in miscarriage. METHODS: Placenta and decidua were collected after termination of apparently normal pregnancies (controls, n = 22) or spontaneous miscarriage (n = 20). Immunohistochemical staining, Western Blot and qRT-PCR were performed for CYP27B1, CYP24A1, CYP2R1, VDR and DBP (not qRT-PCR). HTR-8/SVneo cells were cultured in CoCL2 (hypoxic mimetic) or LPS (bacterial infection mimetic) for 24 h, RNA extracted and qRT-PCR performed for CYP27B1, CYP24A1, CYP2R1 and VDR. RESULTS: In spontaneous miscarriage, placental and decidual expression of CYP27B1 was reduced, while expression of CYP24A1, VDR and DBP was increased. When a trophoblast cell line was treated with CoCL2 expression of CYP27B1 was increased and CYP24A1 was reduced, while LPS induced expression of VDR. DISCUSSION: This is the first report of altered utero-placental vitamin D catabolism in spontaneous miscarriage. It is becoming accepted that women who are undergoing assisted reproductive technologies should ensure they have sufficient vitamin D levels prior to pregnancy, these data support that all women should ensure they are vitamin D replete before planning to get pregnant.
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Aborto Espontâneo/etiologia , Sistema Enzimático do Citocromo P-450/metabolismo , Decídua/enzimologia , Receptores de Calcitriol/metabolismo , Proteína de Ligação a Vitamina D/metabolismo , Vitamina D/metabolismo , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/metabolismo , Aborto Espontâneo/sangue , Aborto Espontâneo/enzimologia , Estudos de Casos e Controles , Colestanotriol 26-Mono-Oxigenase/metabolismo , Família 2 do Citocromo P450/metabolismo , Feminino , Humanos , Gravidez , Vitamina D3 24-Hidroxilase/metabolismoRESUMO
Early warning systems to predict infectious disease outbreaks have been identified as a key adaptive response to climate change. Warming, climate variability and extreme weather events associated with climate change are expected to drive an increase in frequency and intensity of mosquito-borne disease (MBD) outbreaks globally. In Canada, this will mean an increased risk of endemic and emerging MBD outbreaks such as West Nile virus and other MBDs. The availability of timely information on the risk of impending MBD outbreaks has important public health implications, by allowing implementation of mosquito control measures and targeted communications regarding the need for increased personal protective measures-before an outbreak occurs. In Canada, both mechanistic and statistical weather-based models have been developed to predict West Nile virus outbreaks. These include models for different species of mosquitoes that transmit West Nile virus in different geographical areas of Canada. Although initial results have been promising, further validation and assessment of forecasting skill are needed before wide scale implementation. Weather-based forecasting for other emerging MBDs in Canada, such as Eastern equine encephalitis, may also be feasible.
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The Asian tiger mosquito Aedes albopictus is able to transmit various pathogens to humans and animals and it has already caused minor outbreaks of dengue and chikungunya in southern Europe. Alarmingly, it is spreading northwards and its eggs have been found in the UK in 2016 and 2017. Climate-driven models can help to analyse whether this originally subtropical species could become established in northern Europe. But so far, these models have not considered the impact of the diurnal temperature range (DTR) experienced by mosquitoes in the field. Here, we describe a dynamical model for the life cycle of Ae. albopictus, taking into account the DTR, rainfall, photoperiod and human population density. We develop a new metric for habitat suitability and drive our model with different climate data sets to analyse the UK's suitability for this species. For now, most of the UK seems to be rather unsuitable, except for some densely populated and high importation risk areas in southeast England. But this picture changes in the next 50 years: future scenarios suggest that Ae. albopictus could become established over almost all of England and Wales, indicating the need for continued mosquito surveillance.
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Aedes/fisiologia , Mudança Climática , Ecossistema , Modelos Biológicos , Mosquitos Vetores/fisiologia , Animais , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/transmissão , Dengue/epidemiologia , Dengue/transmissão , Inglaterra/epidemiologia , Humanos , País de Gales/epidemiologiaRESUMO
In 2006, bluetongue (BT), a disease of ruminants, was introduced into northern Europe for the first time and more than two thousand farms across five countries were affected. In 2007, BT affected more than 35,000 farms in France and Germany alone. By contrast, the UK outbreak beginning in 2007 was relatively small, with only 135 farms in southeast England affected. We use a model to investigate the effects of three factors on the scale of BT outbreaks in the UK: (1) place of introduction; (2) temperature; and (3) animal movement restrictions. Our results suggest that the UK outbreak could have been much larger had the infection been introduced into the west of England either directly or as a result of the movement of infected animals from southeast England before the first case was detected. The fact that air temperatures in the UK in 2007 were marginally lower than average probably contributed to the UK outbreak being relatively small. Finally, our results indicate that BT movement restrictions are effective at controlling the spread of infection. However, foot-and-mouth disease restrictions in place before the detection and control of BT in 2007 almost certainly helped to limit BT spread prior to its detection.
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Bluetongue/epidemiologia , Doenças dos Bovinos/epidemiologia , Surtos de Doenças/veterinária , Febre Aftosa/epidemiologia , Animais , Bovinos , Temperatura Baixa , Fazendas/tendências , Modelos Biológicos , Ovinos , Reino UnidoRESUMO
The Ptolemy instrument on the Philae lander (of the Rosetta space mission) was able to make measurements of the major volatiles, water, carbon monoxide and carbon dioxide, directly at the surface of comet 67P/Churyumov-Gerasimenko. We give some background to the mission and highlight those instruments that have already given insights into the notion of water in comets, and which will continue to do so as more results are either acquired or more fully interpreted. On the basis of our results, we show how comets may in fact be heterogeneous over their surface, and how surface measurements can be used in a quest to comprehend the daily cycles of processes that affect the evolution of comets.This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'.
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BACKGROUND: Falls are common among older adults and can lead to serious injuries, including fractures. We aimed to determine associations between anxiety disorders and falls in older adults. METHODS: Participants were 487 men and 376 women aged ≥60 years enrolled in the Geelong Osteoporosis Study, Australia. Using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Non-patient edition (SCID-I/NP), lifetime history of anxiety disorders was determined. Falls were determined by self-report. In men, a falls-risk score (Elderly Falls Screening Test (EFST)) was also calculated. RESULTS: Among fallers, 24 of 299 (8.0%) had a lifetime history of anxiety disorder compared to 36 of 634 (5.7%) non-fallers (p=0.014). Examination of the association between anxiety and falls suggested differential relationships for men and women. In men, following adjustment for psychotropic medications, mobility and blood pressure, lifetime anxiety disorder was associated with falling (OR 2.96; 95%CI 1.07-8.21) and with EFST score (OR 3.46; 95%CI 1.13-10.6). In women, an association between lifetime anxiety disorder and falls was explained by psychotropic medication use, poor mobility and socioeconomic status. LIMITATIONS: Sub-group analyses involving types of anxiety and anxiety disorders over the past 12-months were not performed due to power limitations. CONCLUSION: Although anxiety disorders were independently associated with a 3-fold increase in likelihood of reported falls and high falls risk among men, an independent association was not detected among women. These results may aid in prevention of falls through specific interventions aimed at reducing anxiety, particularly in men.
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Acidentes por Quedas/estatística & dados numéricos , Transtornos de Ansiedade/epidemiologia , Limitação da Mobilidade , Psicotrópicos/uso terapêutico , Classe Social , Idoso , Idoso de 80 Anos ou mais , Austrália/epidemiologia , Manual Diagnóstico e Estatístico de Transtornos Mentais , Feminino , Fraturas Ósseas , Humanos , Vida Independente , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Fatores de Risco , Autorrelato , Fatores SexuaisRESUMO
The surface and subsurface of comets preserve material from the formation of the solar system. The properties of cometary material thus provide insight into the physical and chemical conditions during their formation. We present mass spectra taken by the Ptolemy instrument 20 minutes after the initial touchdown of the Philae lander on the surface of comet 67P/Churyumov-Gerasimenko. Regular mass distributions indicate the presence of a sequence of compounds with additional -CH2- and -O- groups (mass/charge ratios 14 and 16, respectively). Similarities with the detected coma species of comet Halley suggest the presence of a radiation-induced polymer at the surface. Ptolemy measurements also indicate an apparent absence of aromatic compounds such as benzene, a lack of sulfur-bearing species, and very low concentrations of nitrogenous material.
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Sclerostin deficiency, via genetic knockout or anti-Sclerostin antibody treatment, has been shown to cause increased bone volume, density and strength of calluses following endochondral bone healing. However, there is limited data on the effect of Sclerostin deficiency on the formative early stage of fibrocartilage (non-bony tissue) formation and removal. In this study we extensively investigate the early fibrocartilage callus. Closed tibial fractures were performed on Sost(-/-) mice and age-matched wild type (C57Bl/6J) controls and assessed at multiple early time points (7, 10 and 14days), as well as at 28days post-fracture after bony union. External fixation was utilized, avoiding internal pinning and minimizing differences in stability stiffness, a variable that has confounded previous research in this area. Normal endochondral ossification progressed in wild type and Sost(-/-) mice with equivalent volumes of fibrocartilage formed at early day 7 and day 10 time points, and bony union in both genotypes by day 28. There were no significant differences in rate of bony union; however there were significant increases in fibrocartilage removal from the Sost(-/-) fracture calluses at day 14 suggesting earlier progression of endochondral healing. Earlier bone formation was seen in Sost(-/-) calluses over wild type with greater bone volume at day 10 (221%, p<0.01). The resultant Sost(-/-) united bony calluses at day 28 had increased bone volume fraction compared to wild type calluses (24%, p<0.05), and the strength of the fractured Sost(-/-) tibiae was greater than that that of wild type fractured tibiae. In summary, bony union was not altered by Sclerostin deficiency in externally-fixed closed tibial fractures, but fibrocartilage removal was enhanced and the resultant united bony calluses had increased bone fraction and increased strength.
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Calo Ósseo/patologia , Calo Ósseo/fisiopatologia , Fibrocartilagem/patologia , Fixação de Fratura , Consolidação da Fratura , Glicoproteínas/deficiência , Tíbia/patologia , Proteínas Adaptadoras de Transdução de Sinal , Animais , Fenômenos Biomecânicos , Calo Ósseo/diagnóstico por imagem , Fibrocartilagem/diagnóstico por imagem , Fibrocartilagem/fisiopatologia , Fraturas Fechadas/diagnóstico por imagem , Fraturas Fechadas/patologia , Fraturas Fechadas/fisiopatologia , Glicoproteínas/metabolismo , Imuno-Histoquímica , Peptídeos e Proteínas de Sinalização Intercelular , Camundongos Endogâmicos C57BL , Camundongos Knockout , Tamanho do Órgão , Osteogênese , Tíbia/diagnóstico por imagem , Tíbia/fisiopatologia , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/patologia , Fraturas da Tíbia/fisiopatologia , Microtomografia por Raio-XRESUMO
Around $1.6 billion per year is spent financing anti-malaria initiatives, and though malaria morbidity is falling, the impact of annual epidemics remains significant. Whilst malaria risk may increase with climate change, projections are highly uncertain and to sidestep this intractable uncertainty, adaptation efforts should improve societal ability to anticipate and mitigate individual events. Anticipation of climate-related events is made possible by seasonal climate forecasting, from which warnings of anomalous seasonal average temperature and rainfall, months in advance are possible. Seasonal climate hindcasts have been used to drive climate-based models for malaria, showing significant skill for observed malaria incidence. However, the relationship between seasonal average climate and malaria risk remains unquantified. Here we explore this relationship, using a dynamic weather-driven malaria model. We also quantify key uncertainty in the malaria model, by introducing variability in one of the first order uncertainties in model formulation. Results are visualized as location-specific impact surfaces: easily integrated with ensemble seasonal climate forecasts, and intuitively communicating quantified uncertainty. Methods are demonstrated for two epidemic regions, and are not limited to malaria modeling; the visualization method could be applied to any climate impact.
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Malária/epidemiologia , Malária/etiologia , Clima , Mudança Climática , Surtos de Doenças , Previsões , Humanos , Modelos Teóricos , Chuva , Risco , Estações do Ano , Incerteza , Tempo (Meteorologia)RESUMO
The aim of this study was to use the Palatable Eating Motives Scale (PEMS) to determine if and what motives for eating tasty foods (e.g., junk food, fast food, and desserts) are associated with binge-eating in two diverse populations. BMI and scores on the PEMS, Yale Food Addiction Scale (YFAS), and Binge-eating Scale (BES) were obtained from 247 undergraduates at the University of Alabama at Birmingham (UAB) and 249 weight-loss seeking patients at the UAB EatRight program. Regression analyses revealed that eating tasty foods to forget worries and problems and help alleviate negative feelings (i.e., the 4-item Coping motive) was associated with binge-eating independently of any variance in BES scores due to sex, age, ethnicity, BMI, other PEMS motives, and YFAS scores in both students (R² = .57) and patients (R² = .55). Coping also was associated with higher BMI in students (p < 0.01), and in patients despite their truncated BMI range (p < 0.05). Among students, the motives Conformity and Reward Enhancement were also independently associated with binge-eating. For this younger sample with a greater range of BES scores, eating for these motives, but not for Social ones, may indicate early maladaptive eating habits that could later develop into disorders characterized by binge-eating if predisposing factors are present. Thus, identifying one's tasty food motive or motives can potentially be used to thwart the development of BED and obesity, especially if the motive is Coping. Identifying one's PEMS motives should also help personalize conventional treatments for binge-eating and obesity toward improved outcomes.
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Bulimia/etiologia , Dieta Redutora , Preferências Alimentares , Motivação , Sobrepeso/dietoterapia , Cooperação do Paciente , Estresse Psicológico/prevenção & controle , Adaptação Psicológica , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Alabama , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sobrepeso/psicologia , Aceitação pelo Paciente de Cuidados de Saúde , Escalas de Graduação Psiquiátrica , Estresse Psicológico/fisiopatologia , Estudantes , Universidades , Adulto JovemRESUMO
Sclerostin, encoded by the Sost gene, is an important negative regulator of bone formation that has been proposed to have a key role in regulating the response to mechanical loading. To investigate the effect of long-term Sclerostin deficiency on mechanotransduction in bone, we performed experiments on unloaded or loaded tibiae of 10 week old female Sost-/- and wild type mice. Unloading was induced via 0.5U botulinum toxin (BTX) injections into the right quadriceps and calf muscles, causing muscle paralysis and limb disuse. On a separate group of mice, increased loading was performed on the left tibiae through unilateral cyclic axial compression of equivalent strains (+1200 µe) at 1200 cycles/day, 5 days/week. Another cohort of mice receiving equivalent loads (-9.0 N) also were assessed. Contralateral tibiae served as normal load controls. Loaded/unloaded and normal load tibiae were assessed at day 14 for bone volume (BV) and formation changes. Loss of BV was seen in the unloaded tibiae of wild type mice, but BV was not different between normal load and unloaded Sost-/- tibiae. An increase in BV was seen in the loaded tibiae of wild type and Sost-/- mice over their normal load controls. The increased BV was associated with significantly increased mid-shaft periosteal mineralizing surface/bone surface (MS/BS), mineral apposition rate (MAR), and bone formation rate/bone surface (BFR/BS), and endosteal MAR and BFR/BS. Notably, loading induced a greater increase in periosteal MAR and BFR/BS in Sost-/- mice than in wild type controls. Thus, long-term Sclerostin deficiency inhibits the bone loss normally induced with decreased mechanical load, but it can augment the increase in bone formation with increased load.
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Calcificação Fisiológica/fisiologia , Glicoproteínas/deficiência , Mecanotransdução Celular/fisiologia , Osteogênese/fisiologia , Periósteo/metabolismo , Tíbia/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Toxinas Botulínicas/toxicidade , Calcificação Fisiológica/efeitos dos fármacos , Feminino , Peptídeos e Proteínas de Sinalização Intercelular , Mecanotransdução Celular/efeitos dos fármacos , Camundongos , Camundongos Knockout , Osteogênese/efeitos dos fármacos , Paralisia/induzido quimicamente , Paralisia/genética , Paralisia/metabolismo , Suporte de CargaRESUMO
The purpose of this study was to validate a new scale designed to measure individual motives for eating tasty foods and determine if any specific motive(s) are associated with obesity. The "Palatable Eating Motives Scale" (PEMS) is a self-report measure adapted from the Drinking Motives Questionnaire Revised (DMQ-R). N=150 racially-diverse college students (mean age: 24.4, BMI: 16-51kg/m(2)) were administered the PEMS along with the Binge-Eating Scale (BES) and the Yale Food Addiction Scale (YFAS) to test for convergent and incremental validity and the Sensitivity to Punishment and Reward Questionnaire (SPSRQ) for discriminant validity. The PEMS identified four motives for eating tasty food, the same ones found with the DMQ-R for alcohol intake: Social, Conformity, Enhancement, and Coping motives. The scales had good convergent validity with BES and YFAS scores but discriminated from the broader motivational constructs of inhibition and activation measured by the SPSRQ. Of the PEMS motives, Coping (eating tasty food to deal with problems and negative feelings) accounted for unique variance in BMI, and added to variance in BMI contributed by BES scores, showing incremental validity. YFAS scores did not contribute to BMI after controlling for binge-eating. Coping subscale scores were also significantly higher (p<0.001) among the severely obese (BMI>40). Motives behind palatable food intake are not homogenous and should be considered in personalized weight-loss strategies in future studies. In normal weight individuals, knowing one's dominant motive for eating tasty foods may help promote healthier food choices in times and places where they are most vulnerable to do otherwise.
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Dieta/psicologia , Ingestão de Alimentos/psicologia , Comportamento Alimentar , Preferências Alimentares , Motivação , Obesidade/psicologia , Prazer , Adaptação Psicológica , Adolescente , Adulto , Consumo de Bebidas Alcoólicas , Comportamento Aditivo , Índice de Massa Corporal , Bulimia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Grupos Raciais , Autorrelato , Conformidade Social , Estudantes , Inquéritos e Questionários , Paladar , Adulto JovemRESUMO
Four poly(ethylene glycol)-stabilized polyamine latexes, namely, poly(2-vinylpyridine) (P2VP), poly(2-(tert-butylamino)ethyl methacrylate) (PTBAEMA), poly(2-(diethylamino)ethyl methacrylate) (PDEA), and poly(2-(diisopropylamino)ethyl methacrylate) (PDPA) were prepared via emulsion copolymerization using divinylbenzene (DVB) as a cross-linker at 0.80 mol % for all formulations. According to dynamic light scattering studies, the resulting latexes were near-monodisperse and had approximately constant hydrodynamic diameters of 205-220 nm at pH 10; a latex-to-microgel transition was observed at around the respective pKa of each polyamine on addition of acid. The kinetics of swelling of each latex was investigated by the pH-jump method using a commercial stopped-flow instrument. The most rapid swelling was observed for the P2VP latex, which exhibited a characteristic swelling time (t*) of 5 ms. The corresponding t* values for PTBAEMA and PDEA were 25 and 35 ms, respectively, whereas the PDPA particles exhibited significantly slower swelling kinetics (t* = 180 ms). These t* values could not be correlated with either the latex Tg or the polyamine pKa. However, there is a positive correlation between t* and the repeat unit mass of the amine monomer, which suggests that the cationic charge density of the protonated polymer chains may influence the kinetics of swelling. Alternatively, the observed differences in swelling kinetics may simply reflect subtle differences in the DVB cross-link density, with more uniformly cross-linked latexes being capable of responding more quickly to a pH jump. The kinetics of deswelling for the corresponding microgel-to-latex transition was also briefly investigated for the PTBAEMA and P2VP particles. In both cases, much slower rates of deswelling were observed. This suggests that a latexlike "skin" is formed on the outer surface of the microgel particles during their deprotonation, which significantly retards the excretion of both salt and water.
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The emulsion copolymerization of 2-(diethylamino)ethyl methacrylate (DEA) with a divinylbenzene cross-linker in the presence of monomethoxy-capped poly(ethylene glycol) methacrylate (PEGMA) at 70 °C afforded near-monodisperse, sterically stabilized PEGMA-PDEA latexes at 10% solids. Dynamic light scattering studies indicated intensity-average diameters of 190 to 240 nm for these latexes at pH 9. A latex-to-microgel transition occurred on lowering the solution pH to below the latex pKa of 6.9. When dilute HCl/KOH was used to adjust the aqueous pH, a systematic reduction in the cationic microgel hydrodynamic diameter of 80 nm was observed over ten pH cycles as a result of the gradual buildup of background salt. However, no such size reduction was observed when using CO2/N2 gases to regulate the aqueous pH because this protocol does not generate background salt. Thus, the latter approach offers better reversibility, albeit at the cost of slower response times. PEGMA-PDEA microgel does not stabilize Pickering emulsions when homogenized at pH 3 with n-dodecane, sunflower oil, isononyl isononanoate, or isopropyl myristate. In contrast, PEGMA-PDEA latex proved to be a ubiquitous Pickering emulsifier at pH 10, forming stable oil-in-water emulsions with each of these four model oils. Lowering the solution pH from 10 to 3 resulted in demulsification within seconds. This is because these pH-responsive particles undergo a latex-to-microgel transition, which leads to their interfacial desorption. Six successive demulsification/emulsification cycles were performed on these Pickering emulsions using HCl/KOH to adjust the solution pH. Demulsification could also be achieved by purging the emulsion solution with CO2 gas to lower the aqueous pH to 4.8. However, complete phase separation required CO2 purging for 4 h at 20 °C. A subsequent N2 purge raised the aqueous pH sufficiently to induce a microgel-to-latex transition, but rehomogenization did not produce a stable Pickering emulsion. Presumably, a higher pH is required, which cannot be achieved by a N2 purge alone.
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Reagentes de Ligações Cruzadas/síntese química , Emulsificantes/síntese química , Metacrilatos/química , Nylons/química , Dióxido de Carbono/química , Reagentes de Ligações Cruzadas/química , Emulsificantes/química , Concentração de Íons de Hidrogênio , Nitrogênio/química , Tamanho da Partícula , Polietilenoglicóis/química , Propriedades de Superfície , Compostos de Vinila/químicaRESUMO
Emulsion copolymerization of 2-(tert-butylamino)ethyl methacrylate in the presence of divinylbenzene (DVB) cross-linker and monomethoxy-capped poly(ethylene glycol) methacrylate (PEGMA) macromonomer at 70 °C afforded sterically-stabilized latexes at approximately 10% solids at pH 9. Dynamic light scattering and scanning electron microscopy (SEM) confirmed that relatively narrow size distributions were obtained. SEM confirmed the formation of spherical particles in the absence of any DVB cross-linker using a simple batch protocol, but in the presence of DVB it was necessary to use seeded emulsion polymerization under monomer-starved conditions to prevent the formation of latexes with ill-defined non-spherical morphologies. Lightly cross-linked latexes acquired cationic microgel character upon lowering the solution pH due to protonation of the secondary amine groups. Increasing the degree of cross-linking led to a progressively lower effective pK(a) of the copolymer chains from 8.0 to 7.3, which implies a gradual reduction in their basicity. Poly(tert-butylamino)ethyl methacrylate latex proved to be an effective Pickering emulsifier at pH 10, forming stable oil-in-water emulsions when homogenized with either n-dodecane or sunflower oil at 12,000 rpm for 2 min. These Pickering emulsions exhibited pH-responsive behavior: lowering the solution pH to 3 resulted in immediate demulsification due to the spontaneous desorption of the cationic microgels from the oil/water interface. Following rehomogenization at high pH, four successive demulsification/emulsification pH cycles could be achieved without a discernible loss in performance. However, no demulsification occurred on acidification of the fifth cycle, due to the progressive build-up of background salt.
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Congenital pseudarthrosis of the tibia is an uncommon manifestation of neurofibromatosis type 1 (NF1), but one that remains difficult to treat due to anabolic deficiency and catabolic excess. Bone grafting and more recently recombinant human bone morphogenetic proteins (rhBMPs) have been identified as pro-anabolic stimuli with the potential to improve the outcome after surgery. As an additional pharmaceutical intervention, we describe the combined use of rhBMP-2 and the bisphosphonate zoledronic acid in a mouse model of NF1-deficient fracture repair. Fractures were generated in the distal tibiae of neurofibromatosis type 1-deficient (Nf1(+/-)) mice and control mice. Fractures were open and featured periosteal stripping. All mice received 10 µg rhBMP-2 delivered in a carboxymethylcellulose carrier around the fracture as an anabolic stimulus. Bisphosphonate-treated mice also received five doses of 0.02 mg/kg zoledronic acid given by intraperitoneal injection. When only rhBMP but no zoledronic acid was used to promote repair, 75% of fractures in Nf1(+/-) mice remained ununited at three weeks compared with 7% of controls (p < 0.001). Systemic post-operative administration of zoledronic acid halved the rate of ununited fractures to 37.5% (p < 0.07). These data support the concept that preventing bone loss in combination with anabolic stimulation may improve the outcome following surgical treatment for children with congenital pseudarthosis of the tibia and NF1.
Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Proteína Morfogenética Óssea 2/uso terapêutico , Difosfonatos/uso terapêutico , Imidazóis/uso terapêutico , Neurofibromatose 1/complicações , Fraturas da Tíbia/tratamento farmacológico , Animais , Terapia Combinada , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos/métodos , Quimioterapia Combinada , Fixação Interna de Fraturas/métodos , Consolidação da Fratura/efeitos dos fármacos , Fraturas não Consolidadas/prevenção & controle , Camundongos , Camundongos Knockout , Cuidados Pós-Operatórios/métodos , Pseudoartrose/complicações , Pseudoartrose/congênito , Proteínas Recombinantes/uso terapêutico , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/etiologia , Fraturas da Tíbia/cirurgia , Resultado do Tratamento , Microtomografia por Raio-X , Ácido ZoledrônicoRESUMO
This research is a preliminary study conducted to determine the effects of aspirin (acetyl-salicylic acid) and salicylic acid (analgesics and their derivatives) on the antibiotic resistance of ammonia oxidizing bacterium (AOB) (a non-pathogenic environmental microbe) cultured from the Texas Tech University-Water Recovery System that treats a space related wastewater for NASA. The effect of salicylic acid was investigated by obtaining the minimal inhibition concentration (MIC) of antibiotics (amoxicillin, ciprofloxacin, and nalidixic acid) in the presence of aspirin and salicylic acid. The possibility of transfer of resistance genes between unrelated species was investigated by analyzing the similarity of the AcrA protein (a multi-drug efflux protein) in Nitrosomonas europaea, Escherichia coli and Salmonella enterica. The protein alignment analysis was done using ExPASy, a proteomics tool. The results of this preliminary study indicated that the antibiotic resistance of AOBs increased in the presence of aspirin and salicylic acid and similarities in the AcrA protein of different species indicated the likelihood of possible resistance transfer between the species. This paper high lights the importance of research and further investigation on antibiotic resistance and resistance transfer, highlighting the number of parameters that should be considered while assessing antibiotic resistance in environmental samples.