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1.
Nanomaterials (Basel) ; 14(7)2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38607149

RESUMO

Owing to the growing concerns about the dwindling fossil fuel reserves, increasing energy demand, and climate emergency, it is imperative to develop and deploy sustainable energy technologies to ensure future energy supply and to transition to the net-zero world. In this context, there is great potential in the biorefinery concept for supplying drop in biofuels in the form of biodiesel. Biodiesel as a fuel can certainly bridge the gap where electrification or the use of hydrogen is not feasible, for instance, in heavy vehicles and in the farm and marine transportation sectors. However, the biodiesel industry also generates a large amount of crude glycerol as the by-product. Due to the presence of several impurities, crude glycerol may not be a suitable feedstock for all high-value products derived from glycerol, but it fits well with glycerol esterification for producing glycerol acetins, which have numerous applications. This review critically looks at the processes using nanostructured solid/liquid acid catalysts for glycerol esterification, including the economic viability of the scale-up. The homogeneous catalysts reviewed herein include mineral acids and Brønsted acidic ionic liquids, such as SO3H-functionalized and heteropoly acid based ionic liquids. The heterogeneous catalysts reviewed herein include solid acid catalysts such as metal oxides, ion-exchange resins, zeolites, and supported heteropoly acid-based catalysts. Furthermore, the techno-economic analysis studies have shown the process to be highly profitable, confirming the viability of glycerol esterification as a potential tool for economic value addition to the biorefinery industry.

2.
Ind Eng Chem Res ; 62(45): 19095-19103, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-38020789

RESUMO

Glycerol acetins (mono-, di-, and tri) are produced via esterification with acetic acid. The acetins are commercially important industrial chemicals including their application as fuel additives, thus significant to environmental sustainability and economic viability of the biorefinery industry. Glycerol esterification with acetic acid was studied using partial tin exchanged tungstophosphoric acid supported on montmorillonite K-10 as catalysts. Partially exchanging the H+ ion of DTP with Sn (x = 1) increased the acidity of the catalyst and showed an increase in the catalytic activity as compared to the DTP/K-10 catalyst. A series of tin exchanged tungstophosphoric acid (20% w/w) supported on montmorillonite K-10 clay (Snx-DTP/K-10, where x = 0.5-1.5) were synthesized and thoroughly characterized by using BET, XRD, FT-IR, UV-vis, and titration techniques. Among various catalysts, Sn1-DTP/K-10 was found to be the most active catalyst for glycerol esterification. Effects of different reaction parameters were studied and optimized to get high yields of glycerol triacetin. A suitable kinetic model of the reaction was fitted, and the Langmuir-Hinshelwood (L-H) dual-site model was able to describe the experimental data with high agreement between the experimental and calculated results. The prepared catalyst could be recycled at least four times without significant loss of activity. The overall process is green and environment friendly.

3.
Ind Eng Chem Res ; 62(23): 9201-9210, 2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37333489

RESUMO

Glycerol is a valuable feedstock, produced in biorefineries as a byproduct of biodiesel production. Esterification of glycerol with acetic acid yields a mixture of mono-, di-, and triacetins. The acetins are commercially important value-added products with a wide range of industrial applications as fuel additives and fine chemicals. Esterification of glycerol to acetins substantially increases the environmental sustainability and economic viability of the biorefinery concept. Among the acetins, diacetin (DA) and triacetin (TA) are considered high-energy-density fuel additives. Herein, we have studied the economic feasibility of a facility producing DA and TA by a two-stage process using 100,000 tons of glycerol per year using Aspen Plus. The capital costs were estimated by Aspen Process Economic Analyzer software. The analysis indicates that the capital costs are 71 M$, while the operating costs are 303 M$/year. The gross profit is 60.5 M$/year, while the NPV of the project is 235 M$ with a payback period of 1.7 years. Sensitivity analysis has indicated that the product price has the most impact on the NPV.

4.
ACS Org Inorg Au ; 3(1): 27-34, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36748078

RESUMO

The manufacture of high-value products from biomass derived platform chemicals is becoming an integral part of the biorefinery industry. In this study, we demonstrate a green catalytic process using solvent free conditions for the synthesis of hydroxymethylfurfural (HMF) levulinate from HMF and levulinic acid (LA) over tin exchanged tungstophosphoric acid (DTP) supported on K-10 (montmorillonite K-10 clay) as the catalyst. The structural properties of solid acid catalysts were characterized by using XRD, FT-IR, UV-vis, titration, and SEM techniques. Partial exchange of the H+ of DTP with Sn (x = 1) resulted in enhanced acidity of the catalyst and showed an increase in the catalytic activity as compared to the unsubstituted DTP/K-10 as the catalyst. The effects of different reaction parameters were studied and optimized to get high yields of HMF levulinate. The kinetic model was developed by considering the Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism, and the activation energy was calculated to be 41.2 kJ mol-1. The prepared catalysts were easily recycled up to four times without any noticeable loss of activity, and hot filtration test indicated the heterogeneous nature of the catalytic activity. The overall process is environmentally benign and suitable for easy scale up.

5.
Circ Econ Sustain ; 3(1): 125-166, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35818534

RESUMO

The circular economy (CE) field has recently attracted significant interest from academics and practitioners. CE represents a departure from the linear economy, which is characterised by unsustainable resource production and consumption. The growing number of publications necessitates a comprehensive analysis of this field. This is the first systematic examination of the knowledge base and knowledge diffusion pathways in the CE domain. We analyse a Web of Science dataset containing 5431 articles published between 1970 and 2020. To create a comprehensive review of the CE domain, we conducted a keyword co-occurrence network analysis. We examined four distinct types of main paths using the main path analysis (MPA) technique: forward, backward, global, and key-route. According to the analyses, CE research focuses on six primary research themes: CE and sustainability, bioeconomy, CE practices, lifecycle assessment and industrial symbiosis, construction activities, and waste management. In addition, the MPA demonstrates that the CE literature has recently focused on Industry 4.0 technologies and their contribution to CE. This is the first attempt to depict the genealogy of CE research so that scholars can comprehend the domain's evolutionary structure, identify hot topics, and capture the history, development status, and potential future directions of CE research.

6.
Qual Quant ; 56(5): 2875-2906, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34629554

RESUMO

Blockchain can function as a foundational technology with numerous applications in smart cities. The objective of this paper is twofold. First, it provides a detailed overview of the extant literature on blockchain applications in smart cities; second, it reveals the trends and suggests future research directions for scholars who wish to contribute to this rapidly growing field. We conducted a bibliometric review using a keyword co-occurrence network and article co-citation analysis. The analysis includes the assessment of 148 articles published between 2016 and 2020 in 76 academic journals. The review results demonstrate that the number of articles devoted to the study of blockchain applications and smart cities has increased exponentially in recent years. More importantly, the research identifies some of the most influential studies in this area. The paper discusses trends and highlights the challenges related to the deployment of blockchain in smart cities. To the authors' best knowledge, this represents the first study to review the literature from leading journals on blockchain applications in smart cities using bibliometric techniques.

7.
Tech Innov Gastrointest Endosc ; 23(3): 226-233, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34458878

RESUMO

BACKGROUND AND AIMS: Increasing demand for inpatient endoscopic services results in performing more non-emergent endoscopic cases after-hours, which poses risks to patient safety and negatively impacts patient and provider satisfaction. This study sought to quantify the existing state using quality improvement (QI) methodology, design targeted interventions, and determine their effectiveness. METHODS: We conducted an existing state evaluation through a process map, time-series study, and caseload analysis from 7/2017-12/2018. Using end-of-workday (EOW) as a proxy for patient/provider dissatisfaction and risk for patient safety events, we performed a prospective evaluation of a staged interdisciplinary multimodal intervention aimed to decrease the proportion of days with EOW after 7PM, decrease the proportion of cases begun after 5PM, and decrease EOW variability. The post-intervention period was 6/2019-2/2020. RESULTS: Based on existing state analyses, we implemented a series of targeted interventions: (1) provider workflow tips, (2) expedited transport for select patients, (3) pathway to reschedule appropriate cases to outpatient endoscopy, and (4) increased staffing for high caseload days through resource pooling. The proportion of days with EOW after 7PM decreased from 42.4% to 29.3% (caseload-adjusted odds ratio of 0.39, p< 0.001). Despite increased caseload, cases begun after 5PM decreased from 17.5% to 14.2% (OR 0.75, p = 0.009). EOW SD decreased from 2:20 hours to 1:36 hours. CONCLUSIONS: The multimodal intervention reduced days with EOW after 7PM and the proportion of cases begun after 5PM, despite increased caseload. This study shows how applying research methods to implement QI interventions successfully decreases late inpatient endoscopic cases.

8.
Mar Pollut Bull ; 151: 110802, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32056597

RESUMO

In assessing the overall status of individual water bodies the EU Water Framework Directive (WFD) requires member states to assess both ecological and chemical status. The ecological status of transitional and coastal (TraC) waters is based on the assessment of specific biological elements as well as supporting chemical, physico-chemical and hydromorphological elements. Hydromorphology of TraC waters is one of the basic features of marine and coastal ecosystems controlling the presence of biota. Human induced hydromorphological alterations and pressures can damage the ecology and functioning of aquatic ecosystems. Thirteen metrics were developed and combined to form a hydromorphological index, the Hydromorphological Quality Index (HQI). The index categorises a water body into 5 classes. Semi-qualitative and quantitative criteria were used to assign a morphological classification directly related to that of the WFD, i.e., high, good, moderate, poor and bad. Thirty-three transitional and coastal water bodies were assessed using HQI.


Assuntos
Ecossistema , Monitoramento Ambiental , Biota , Ecologia , Irlanda
9.
Infect Disord Drug Targets ; 20(3): 291-302, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30306881

RESUMO

BACKGROUND: Congenital cytomegalovirus (cCMV) is known to cause childhood deafness, neurodevelopmental disability and death. Simple hygiene precautions are effective in reducing maternal risk of CMV infection. OBJECTIVE: To review i) awareness of CMV infection and available primary prevention strategies both in the community and amongst health professionals ii) available cCMV information sources in the literature, grey literature and published professional guidelines. METHODS: Scoping study to i) identify literature pertaining to cCMV awareness amongst parents and health professionals using MedLine and CINAHL databases via EBSCO ii) review one high income country's guidelines and recommendations regarding cCMV infection and pregnancy (example country Australia) iii) grey literature for parental information. RESULTS: Worldwide awareness of cCMV and of available prevention strategies amongst women and health professionals are poor. Findings internationally suggest at least half of maternity care health professionals do not routinely provide advice to women regarding simple hygiene precautions that can reduce their risk of infection during pregnancy. Though information resources regarding cCMV are available, they are frequently not included within general healthy pregnancy advice and require individuals to search for 'congenital cytomegalovirus'. CONCLUSION: cCMV is a preventable cause of serious congenital disability and death. Prevention opportunities are being missed because most women are not aware of cCMV or how to reduce their risk of infection in pregnancy, in part due to poor health professional awareness. New strategies to disseminate cCMV information to the community and to support health professionals to embed cCMV advice within routine pregnancy counselling is required.


Assuntos
Infecções por Citomegalovirus/congênito , Infecções por Citomegalovirus/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Política de Saúde , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Complicações Infecciosas na Gravidez/prevenção & controle , Feminino , Humanos , Transmissão Vertical de Doenças Infecciosas/legislação & jurisprudência , Masculino , Gravidez , Complicações Infecciosas na Gravidez/virologia
10.
J Food Sci ; 84(10): 2705-2718, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31546281

RESUMO

The food industry is advancing at a rapid pace and consumer sensitivity to food safety scares and food fraud scandals is further amplified by rapid communication such as by social media. Academia, regulators, and industry practitioners alike struggle with an evolving issue regarding new terms and definitions including food fraud, food authenticity, food integrity, food protection, economically motivated adulteration, food crime, food security, contaminant, adulterant, and others. This research addressed some of the global need for clarification and harmonization of commonly used terminology. The 150 survey responses were received from various food-related workgroups or committee members, communication with recognized experts, and announcements to the food industry in general. Overall food fraud was identified as a "food safety" issue (86%). The food quality and manufacturing respondents focused mainly on incoming goods and adulterant-substances (<50%) rather than the other illegal activities such as counterfeiting, theft, gray market/diversion, and smuggling. Of the terms included to represent "intentional deception for economic gain" the respondents generally agreed with food fraud as the preferred term. Overall, the preference was 50% "food fraud," 15% "economically motivated adulteration" EMA, 9% "food protection," 7% "food integrity," 5% "food authenticity," and 2% "food crime." It appears that "food protection" and "food integrity" are terms that cover broader concepts such as all types of intentional acts and even possibly food safety or food quality. "Food authenticity" was defined with the phrase "to ensure" so seemed to be identified as an "attribute" that helped define fraudulent acts. PRACTICAL APPLICATION: Food Fraud-illegal deception for economic gain using food-is a rapidly evolving research topic and is facing confusion due to the use of different terms and definitions. This research survey presented common definitions and publication details to gain insight that could help provide clarity. The insight from this report provides guidance for others who are harmonizing terminology and setting the overall strategic direction.


Assuntos
Contaminação de Alimentos/legislação & jurisprudência , Fraude/legislação & jurisprudência , Terminologia como Assunto , Contaminação de Alimentos/análise , Contaminação de Alimentos/economia , Inocuidade dos Alimentos , Abastecimento de Alimentos/economia , Abastecimento de Alimentos/legislação & jurisprudência , Fraude/economia , Humanos
11.
Ann Allergy Asthma Immunol ; 121(5): 537-544, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30248407

RESUMO

OBJECTIVE: To review the history of the penicillin minor determinants and evaluate their relevance for current diagnosis. DATA SOURCES: Skin testing to detect immunoglobulin E (IgE) sensitivity to penicillins in patients with a history of penicillin allergy has been the subject of more than 55 years of published research involving tens of thousands of patients. STUDY SELECTIONS: Selection of data was based on its relevance to the objective of this article. RESULTS: It was established early on that testing with the major penicilloyl determinant using the polyvalent penicilloyl-polylysine (PPL) is negative in a substantial portion (10% to 64%, including recent increases) of those at risk for immediate hypersensitivity reactions. A variety of minor penicillin determinants are clinically significant in that their use in skin testing is essential to detect all those at risk. In particular, a minor determinant mixture of benzylpenicillin, benzylpenicilloate, and benzylpenilloate, used in conjunction with PPL, has been shown in numerous studies to achieve an average negative predictive value (NPV) of 97.9% in history-positive patients. Benzylpenicillin alone, as the sole minor determinant, leaves many skin test-positive patients undiscovered. Use of amoxicillin as an additional minor determinant reagent appears to identify another 2% to 8% of skin test-positive patients in some populations. CONCLUSION: IgE skin testing, using both the major and appropriate minor determinants of penicillin, can identify, with a high degree of reliability (NPV ∼97%), penicillin allergy history-positive patients who can receive beta-lactam antibiotics without concern for serious acute allergy, including anaphylaxis. The few false-negative skin tests reported globally are largely confined to minor, self-limited cutaneous reactions.


Assuntos
Hipersensibilidade a Drogas/diagnóstico , Penicilinas/efeitos adversos , Penicilinas/imunologia , Anafilaxia , Humanos , Imunoglobulina E , Valor Preditivo dos Testes , Testes Cutâneos
13.
Langmuir ; 32(6): 1577-84, 2016 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-26794208

RESUMO

Polymerization of substrate-supported bilayers composed of dienoylphosphatidylcholine (PC) lipids is known to greatly enhance their chemical and mechanical stability; however, the effects of polymerization on membrane fluidity have not been investigated. Here planar supported lipid bilayers (PSLBs) composed of dienoyl PCs on glass substrates were examined to assess the degree to which UV-initiated polymerization affects lateral lipid mobility. Fluorescence recovery after photobleaching (FRAP) was used to measure the diffusion coefficients (D) and mobile fractions of rhodamine-DOPE in unpolymerized and polymerized PSLBs composed of bis-sorbyl phosphatidylcholine (bis-SorbPC), mono-sorbyl-phosphatidylcholine (mono-SorbPC), bis-dienoyl-phosphatidylcholine (bis-DenPC), and mono-dienoyl phosphatidylcholine (mono-DenPC). Polymerization was performed in both the Lα and Lß phase for each lipid. In all cases, polymerization reduced membrane fluidity; however, measurable lateral diffusion was retained which is attributed to a low degree of polymerization. The D values for sorbyl lipids were less than those of the denoyl lipids; this may be a consequence of the distal location of polymerizable group in the sorbyl lipids which may facilitate interleaflet bonding. The D values measured after polymerization were 0.1-0.8 of those measured before polymerization, a range that corresponds to fluidity intermediate between that of a Lα phase and a Lß phase. This D range is comparable to ratios of D values reported for liquid-disordered (Ld) and liquid-ordered (Lo) lipid phases and indicates that the effect of UV polymerization on lateral diffusion in a dienoyl PSLB is similar to the transition from a Ld phase to a Lo phase. The partial retention of fluidity in UV-polymerized PSLBs, their enhanced stability, and the activity of incorporated transmembrane proteins and peptides is discussed.


Assuntos
Bicamadas Lipídicas/química , Fluidez de Membrana/efeitos da radiação , Fosfatidilcolinas/química , Fosfatidiletanolaminas/química , Rodaminas/química , Difusão , Recuperação de Fluorescência Após Fotodegradação , Bicamadas Lipídicas/efeitos da radiação , Fosfatidilcolinas/efeitos da radiação , Fosfatidiletanolaminas/efeitos da radiação , Polimerização , Rodaminas/efeitos da radiação , Temperatura de Transição , Raios Ultravioleta
14.
Anesthesiol Clin ; 33(4): 731-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26610626

RESUMO

Ambulatory anesthesia's popularity continues to increase and techniques continue to adapt to the needs of patients. Alterations in existing medications are promising. Postoperative nausea and vomiting, pain, obstructive sleep apnea, and chronic comorbidities are concerns in ambulatory settings. Regional anesthesia has multiple advantages over general anesthesia. The implementation of the Affordable Health Care Act specifically affects ambulatory settings as the demand and need for patients to undergo screening procedures with anesthesia. The question remains what the best strategy is to meet the needs of our future patients while preserving economic feasibility within an already strained health care system.


Assuntos
Procedimentos Cirúrgicos Ambulatórios , Anestesia/normas , Anestesiologia/normas , Complicações Pós-Operatórias/prevenção & controle , Humanos
15.
Int J Pharm ; 496(2): 834-41, 2015 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-26475971

RESUMO

The organic cation transporters OCT and OCTN have been reported to play a significant role in the cellular uptake of substrates within in vitro lung cells. However, no studies to date have investigated the effect of these transporters upon transepithelial absorption of substrates into the pulmonary circulation. We investigated the contribution of OCT and OCTN transporters to total pulmonary absorption of l-carnitine and the anti-muscarinic drug, ipratropium, across an intact isolated perfused rat lung (IPRL). The results obtained from the IPRL were contrasted with active transport in vitro using three human pulmonary cell lines and primary rat alveolar epithelial cells. Ex-vivo studies showed that OCT/OCTN transporters do not play a role in the overall pulmonary absorption of l-carnitine or ipratropium, as evidenced by the effect of chemical inhibition of these transporters upon pulmonary absorption. In contrast, in vitro studies showed that OCT/OCTN transporters play a significant role in cellular accumulation of substrates with preferential uptake of ipratropium by OCTs, and of l-carnitine uptake by OCTNs. The results show that in vitro uptake studies cannot be predictive of airway to blood absorption in vivo. Nevertheless, localised submucosal pulmonary concentrations of inhaled drugs and their pulmonary pharmacodynamic profiles may be influenced by OCT/OCTN transport activity.


Assuntos
Carnitina/farmacocinética , Ipratrópio/farmacocinética , Pulmão/metabolismo , Proteínas de Transporte de Cátions Orgânicos/fisiologia , Animais , Proteínas de Transporte/fisiologia , Células Cultivadas , Células Epiteliais/metabolismo , Humanos , Proteínas de Membrana/fisiologia , Circulação Pulmonar , Ratos , Membro 5 da Família 22 de Carreadores de Soluto , Proteínas Carreadoras de Solutos , Simportadores
16.
Curr Opin Anaesthesiol ; 28(6): 617-22, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26485204

RESUMO

PURPOSE OF REVIEW: The purpose of this review is to discuss current practices and changes in the field of ambulatory anesthesia, in both hospital and ambulatory surgery center settings. New trends in ambulatory settings are discussed and a review of the most current and comprehensive guidelines for the care of ambulatory patients with comorbid conditions such as postoperative nausea and vomiting (PONV), obstructive sleep apnea and diabetes mellitus are reviewed. Future direction and challenges to the field are highlighted. RECENT FINDINGS: Ambulatory anesthesia continues to be in high demand for many reasons; patients and surgeons want their surgical procedures to be swift, involve minimal postoperative pain, have a transient recovery time, and avoid an admission to the hospital. Factors that have made this possible for patients are improved surgical equipment, volatile anesthetic improvement, ultrasound-guided regional techniques, non-narcotic adjuncts for pain control, and the minimization of PONV. The decrease in time spent in a hospital also decreases the risk of wound infection, minimizes missed days from work, and is a socioeconomically favorable model, when possible. Recently proposed strategies which will allow surgeons and anesthesiologists to continue to meet the growing demand for a majority of surgical cases being same-day include pharmacotherapies with less undesirable side-effects, integration of ultrasound-guided regional techniques, and preoperative evaluations in appropriate candidates via a telephone call the night prior to surgery. Multidisciplinary communication amongst caregivers continues to make ambulatory settings efficient, safe, and socioeconomically favorable.It is also important to note the future impact that healthcare reform will have specifically on ambulatory anesthesia. The enactment of the Patient Protection and Affordable Care Act of 2010 will allow 32 million more people to gain access to preventive services that will require anesthesia such as screening colonoscopies. With this projected increase in the demand for anesthesia services nationwide comes the analysis of its financial feasibility. Some early data looking at endoscopist-administered sedation conclude that it offers higher patient satisfaction, there were less adverse effects than anesthesiologist-administered sedation, and is economically advantageous. This and future retrospective studies will help to guide healthcare policymakers and physicians to come to a conclusion about providing ambulatory services for these millions of patients. SUMMARY: Ambulatory anesthesia's popularity continues to rise and anesthetic techniques will continue to morph and adapt to the needs of patients seeking ambulatory surgery. Alterations in already existing medications are promising as these modifications allow for quicker recovery from anesthesia or minimization of the already known undesirable side-effects. PONV, pain, obstructive sleep apnea, and chronic comorbidities (hypertension, cardiac disease, and diabetes mellitus) are perioperative concerns in ambulatory settings as more patients are safely being treated in ambulatory settings. Regional anesthesia stands out as a modality that has multiple advantages to general anesthesia, providing a minimal recovery period and a decrease in postanesthesia care unit stay. The implementation of the Affordable Healthcare Act specifically affects ambulatory settings as the demand and need for patients to have screening procedures with anesthesia. The question remains what the best strategy is to meet the needs of our future patients while preserving economically feasibility within an already strained healthcare system.


Assuntos
Assistência Ambulatorial/métodos , Anestesia/métodos , Anestesia/normas , Procedimentos Cirúrgicos Ambulatórios , Humanos , Satisfação do Paciente , Guias de Prática Clínica como Assunto
17.
Anal Bioanal Chem ; 407(3): 953-60, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25326888

RESUMO

A porous phospholipid nanoshell (PPN) sensor functionalized with a specific aptamer sensor agent was prepared for rapid detection of Hg(2+) in human urine with minimal sample preparation. Aptamer sensors provide an important class of optical transducers that can be readily and reproducibly synthesized. A key limitation of aptamer sensors, and many other optical sensors, is the potential of biofouling or biodegradation when used in complex biological matrices such as serum or urine, particularly when high levels of nucleases are present. We prepared Hg(2+)-responsive, PPN-encapsulated aptamer sensors that overcome these limitations. PPNs provide a protective barrier to encapsulate the aptamer sensor in an aqueous environment free of diffusional restrictions encountered with many polymer nanomaterials. The unique porous properties of the PPN membrane enable ready and rapid transfer of small molecular weight ions and molecules into the sensor interior while minimizing the macromolecular interactions between the transducer and degradants or interferents in the exterior milieu. Using Hg(2+)-responsive, PPN-encapsulated aptamer sensors, we were able to detect sub-100 ppb (chronic threshold limit from urine test) Hg(2+) in human urine with no sample preparation, whereas free aptamer sensors yielded inaccurate results due to interferences from the matrix. The PPN architecture provides a new platform for construction of aptamer-functionalized sensors that target low molecular weight species in complex matrices, beyond the Hg(2+) demonstrated here.


Assuntos
Aptâmeros de Nucleotídeos/química , Mercúrio/urina , Nanoconchas/química , Fosfolipídeos/química , Urinálise/métodos , Aptâmeros de Nucleotídeos/metabolismo , Técnicas Biossensoriais/métodos , Calibragem , Humanos , Lipossomos , Mercúrio/metabolismo , Porosidade , Espectrometria de Fluorescência/instrumentação , Espectrometria de Fluorescência/métodos , Urinálise/instrumentação
18.
Obstet Gynecol ; 122(4): 869-877, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24084547

RESUMO

OBJECTIVE: To examine the antecedents of cerebral palsy and of perinatal death in singletons born at or after 35 weeks of gestation. METHODS: From a total population of singletons born at or after 35 weeks of gestation, we identified 494 with cerebral palsy and 508 neonates in a matched control group, 100 neonatal deaths, and 73 intrapartum stillbirths (all deaths in selected birth years). Neonatal death and cerebral palsy were categorized as without encephalopathy, after neonatal encephalopathy, or after neonatal encephalopathy considered hypoxic-ischemic. We examined the contribution of potentially asphyxial birth events, inflammation, fetal growth restriction, and birth defects recognized by age 6 years to each of these outcomes and to intrapartum stillbirths. RESULTS: The odds of total cerebral palsy after potentially asphyxial birth events or inflammation were modestly increased (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.1-3.2 and OR 2.2, 95% CI 1.0-4.2, respectively). However, potentially asphyxial birth events occurred in 34% of intrapartum stillbirths and 21.6% of cerebral palsy after hypoxic-ischemic encephalopathy. Inflammatory markers occurred in 13.9% and 11.9% of these outcomes, respectively. Growth restriction contributed significantly to all poor outcome groups. Birth defects were recognized in 5.5% of neonates in the control group compared with 60% of neonatal deaths and more than half of cases of cerebral palsy without hypoxic-ischemic encephalopathy. In children with cerebral palsy, a potentially asphyxial birth event, inflammation, or both were experienced by 12.6%, whereas growth restriction, a birth defect, or both were experienced by 48.6% (P<.001). CONCLUSION: Fetal growth restriction and birth defects recognized by age 6 years were more substantial contributors to cerebral palsy and neonatal death than potentially asphyxial birth events and inflammation. LEVEL OF EVIDENCE: : II.


Assuntos
Asfixia Neonatal/complicações , Paralisia Cerebral/etiologia , Retardo do Crescimento Fetal/mortalidade , Mortalidade Perinatal , Nascimento Prematuro/mortalidade , Asfixia Neonatal/mortalidade , Estudos de Casos e Controles , Causas de Morte , Anormalidades Congênitas/epidemiologia , Feminino , Humanos , Recém-Nascido , Gravidez , Natimorto/epidemiologia , Austrália Ocidental/epidemiologia
19.
Anal Chim Acta ; 772: 93-8, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23540253

RESUMO

Phosphorylcholine (PC) based phospholipid bilayers have proven useful as capillary coating materials due to their inherent resistance to non-specific protein adsorption. The primary limitation of this important class of capillary coatings remains the limited long-term chemical and physical stability of the coatings. Recently, a method for increasing phospholipid coating stability in fused silica capillaries via utilization of polymerized, synthetic phospholipids was reported. Here, we expand upon these studies by investigating polymerized lipid bilayer capillary coatings with respect to separation performance including run-to-run, day-to-day and column-to-column reproducibility and long-term stability. In addition, the effects of pH and capillary inner diameter on polymerized phospholipid coated capillaries were investigated to identify optimized coating conditions. The coatings are stabilized for protein separations across a wide range of pH values (4.0-9.3), a unique property for capillary coating materials. Additionally, smaller inner diameter capillaries (≤50 µm) were found to yield marked enhancements in coating stability and reproducibility compared to wider bore capillaries, demonstrating the importance of capillary size for separations employing polymerized phospholipid coatings.


Assuntos
Fracionamento Químico/métodos , Eletroforese Capilar/métodos , Bicamadas Lipídicas/química , Fosfatidilcolinas/química , Proteínas/isolamento & purificação , Adsorção , Fracionamento Químico/instrumentação , Eletroforese Capilar/instrumentação , Concentração de Íons de Hidrogênio , Polimerização , Reprodutibilidade dos Testes , Dióxido de Silício/química
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