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1.
Am J Obstet Gynecol ; 224(1): 105.e1-105.e9, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32682861

RESUMEN

BACKGROUND: Because the global disease burden of cervical cancer is greatest in Africa, the World Health Organization has endorsed visual inspection with acetic acid screening with cryotherapy triage for the screen-and-treat approach. With the lowest doctor-to-patient ratio worldwide (1:50,000), Tanzania has nearly 10,000 new cases of cervical cancer and 7000 deaths annually. OBJECTIVE: We report on the feasibility of visual inspection with acetic acid in the severely resource-limited Mwanza district and on the impact of intervening education on baseline human papillomavirus and cervical cancer knowledge. STUDY DESIGN: Two 5-day free visual inspection with acetic acid (VIA) clinics in urban Buzuruga and rural Sangabuye on the shores of Lake Victoria were approved by our university institutional review board and local Tanzanian health authorities. Participants completed a demographic survey and a 6-question (1 point per question) multiple choice test written in Kiswahili to assess baseline knowledge. A 15-minute educational video in Kiswahili (MedicalAidFilms: Understanding screening, treatment, and prevention of cervical cancer) was followed by repeated assessment using the same test, visual inspection with acetic acid screening, and optional HIV testing. Pre- and postvideo scores and change of score were analyzed via t test, analysis of variance, and multivariate regression. Significance was considered at P<.05. RESULTS: From July 2, 2018 to July 6, 2018, 825 women were screened, and 207 women (25.1%) were VIA positive (VIA+). One hundred forty-seven VIA+ nonpregnant women received same-day cryotherapy. Seven hundred sixty women participated in an educational intervention-61.6% of whom were from an urban site and 38.2% from a rural site. The mean age was 36.4 (standard deviation, 11.1). Primary languages were Kiswahili (62.2%) and Kisukuma (30.6%). Literacy was approximately 73%, and average education level was equivalent to the seventh grade (United States). Less than 20% of urban and rural women reported access to healthcare providers. Mean score of the participants before watching the video was 2.22 (standard deviation, 1.76) and was not different between VIA+ and VIA negative groups. Mean score of the participants after watching the video was 3.86 (standard deviation, 1.78). Postvideo scores significantly improved regardless of age group, clinic site, primary language, education level, literacy, or access to healthcare provider (P<.0001). Change of score after watching the video was significantly greater in participants from urban areas (1.99±2.07) than in those from rural areas (1.07±1.95) (P<.0001). Multivariate analysis identified urban site as an independent factor in change of score (P=.0211). CONCLUSION: Visual inspection with acetic acid screening for cervical cancer is feasible and accepted in northern Tanzania. Short video-based educational intervention improved baseline knowledge on the consequences of human papillomavirus infection in the studied populations. The impact was greater in the urban setting than in the rural setting.


Asunto(s)
Papillomaviridae/aislamiento & purificación , Infecciones por Papillomavirus/diagnóstico , Educación del Paciente como Asunto , Participación del Paciente , Displasia del Cuello del Útero/diagnóstico , Neoplasias del Cuello Uterino/diagnóstico , Frotis Vaginal , Adolescente , Adulto , Femenino , Humanos , Persona de Mediana Edad , Infecciones por Papillomavirus/virología , Población Rural , Tanzanía/epidemiología , Población Urbana , Neoplasias del Cuello Uterino/virología , Adulto Joven , Displasia del Cuello del Útero/virología
2.
J Obstet Gynaecol Res ; 47(12): 4365-4370, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34614540

RESUMEN

AIM: To evaluate visual inspection with acetic acid (VIA) screening for cervical cancer among human immunodeficiency virus (HIV)-positive patients in an East African community. METHODS: During a July 2018 cervical cancer screen-and-treat in Mwanza, Tanzania, participants were offered free cervical VIA screening, cryotherapy when indicated, and HIV testing. Acetowhite lesions and/or abnormal vascularity were designated VIA positive in accordance with current guidelines. The association between VIA results and HIV status was compared using Chi-square and Fisher exact tests. RESULTS: Eight hundred and twenty-four of 921 consented participants underwent VIA screening and 25.0% (n = 206) were VIA positive. VIA-positive nonpregnant women (n = 147) received cryotherapy and 15 (1.8%) with cancerous-appearing lesions were referred to Bugando Hospital. Sixty-six women were HIV-positive and included 25 diagnosed with HIV at the cervical cancer VIA screening and 41 with a prior diagnosis of HIV who were receiving antiretroviral therapy (ART) at the time of cervical cancer VIA screening. Sixty-four of these 66 patients, were screened with VIA. HIV infection was not associated with VIA findings. Abnormal VIA positive screening was observed in 20.3% (n = 13) of HIV-positive patients and in 24.4% (n = 145) of HIV-negative patients (p = 0.508). A nonsignificant trend of higher VIA positive screens among newly diagnosed HIV patients of 26.1% (n = 6) versus patients with preexisting HIV on ART of 17.1% (n = 7) was observed (p = 0.580). CONCLUSION: The unexpected lack of correlation between HIV infection and VIA positivity in a community with access to ART warrants additional research regarding the previously described role of ART in attenuating HPV-mediated neoplasia.


Asunto(s)
Infecciones por VIH , Infecciones por Papillomavirus , Neoplasias del Cuello Uterino , Ácido Acético , Detección Precoz del Cáncer , Femenino , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Humanos , Tamizaje Masivo , Tanzanía/epidemiología , Neoplasias del Cuello Uterino/diagnóstico
3.
J Orthod ; 47(4): 330-337, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32854562

RESUMEN

In 2020, we experienced the largest disruption to normal life recorded in recent years with the COVID-19 global pandemic. Creative thinking was required to ensure patient care was maintained. In this article, we share a service evaluation and experiences dealing with the crisis through using a virtual office approach with video conferencing to manage emergency consultations, treatment reviews, new patient and multidisciplinary clinics in a hospital orthodontic unit.


Asunto(s)
Betacoronavirus , COVID-19 , Infecciones por Coronavirus , Neumonía Viral , Telemedicina , Infecciones por Coronavirus/epidemiología , Odontología , Humanos , Pandemias , Neumonía Viral/epidemiología , SARS-CoV-2
4.
J Pediatr ; 198: 187-193.e1, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29625730

RESUMEN

OBJECTIVE: To study the natural history of postnatal cardiopulmonary adaptation in infants born extremely preterm and establish its association with death or bronchopulmonary dysplasia (BPD). STUDY DESIGN: This was a prospective, observational, cohort study of infants born extremely preterm (<29 weeks). Initial echocardiogram was performed at <48 hours of life, followed by serial echocardiograms every 24-48 hours until 14 days of life. Resolution or no resolution of pulmonary hypertension (PH) at 72-96 hours was considered normal or delayed postnatal cardiopulmonary adaptation, respectively. PH between 96 hours and 14 days was defined as subsequent PH. Elevated pulmonary artery pressure throughout the 14 days of life was considered persistent PH. BPD was assessed at 36 weeks of postmenstrual age. RESULTS: Sixty infants were enrolled; 2 died before a sequential echocardiogram could be done at 72-96 hours. Normal and delayed cardiopulmonary adaptation were noted in 26 (45%) and 32 (55%) infants, respectively. Five patterns of postnatal cardiopulmonary adaptation were recognized: normal without subsequent PH (n = 20), normal with subsequent PH (n = 6), delayed adaptation without subsequent PH (n = 6), delayed adaptation with subsequent PH (n = 16), and persistent PH (n = 10). Infants with delayed cardiopulmonary adaptation were of lower gestation and birth weight and required prolonged ventilation and supplemental oxygen (P < .05). On multivariate analysis, the incidence of death or BPD was significantly greater among infants with delayed adaptation (P < .001). CONCLUSION: Infants born extremely preterm have normal or delayed postnatal cardiopulmonary adaptation that can be complicated by subsequent or persistent PH. Delayed cardiopulmonary adaptation is associated independently with death or BPD.


Asunto(s)
Adaptación Fisiológica/fisiología , Displasia Broncopulmonar/etiología , Hipertensión Pulmonar/fisiopatología , Femenino , Edad Gestacional , Humanos , Hipertensión Pulmonar/complicaciones , Hipertensión Pulmonar/mortalidad , Recien Nacido Extremadamente Prematuro , Recién Nacido , Masculino , Estudios Prospectivos
5.
J Med Internet Res ; 20(12): e297, 2018 12 21.
Artículo en Inglés | MEDLINE | ID: mdl-30578208

RESUMEN

BACKGROUND: Patient and public involvement in health research is important to produce relevant and impactful results. OBJECTIVE: This paper aimed to prioritize and summarize Hirschsprung disease (HD)-related information needs among caregivers of children with HD and pediatric surgeons through partnership with a parent-initiated social media campaign. METHODS: We conducted a Web-based survey with the 2 stakeholder groups to identify information needs. The caregiver survey was conducted through a global Web-based community, and the surgeon survey was distributed to members of the Canadian Association of Paediatric Surgeons (CAPS). We conducted a literature review to identify evidence on the prioritized topics. RESULTS: Our findings showed that 54.9% (89/162) of the individuals completed the caregiver survey and 23.8% (52/218 listed members) of the pediatric surgeons completed the survey distributed through CAPS. Only 20% (18/89) of the caregivers reported being very satisfied or satisfied with the current HD-related resources. A final prioritized list of information needs included bowel management, nutrition and growth, infection, perianal irritation, gastrointestinal pain, surgical diagnostics, and surgical complications. In total, 87 studies were included in the literature review, which included the following: 8 reviews, 2 randomized controlled trials, 74 cohort studies, and 3 practice guidelines. Two priority issues identified by caregivers had only a single study that met the inclusion criteria, whereas 1 topic had none. CONCLUSIONS: With caregiver and surgeon input, we identified 7 information priority areas related to HD. A review of the literature on the priorities found little evidence to support the development of high-quality guidelines. More research is necessary to meet the information needs related to HD as identified by stakeholders.


Asunto(s)
Cuidadores/psicología , Enfermedad de Hirschsprung/terapia , Informática Médica/tendencias , Medios de Comunicación Sociales/tendencias , Niño , Preescolar , Recursos en Salud , Humanos , Lactante , Recién Nacido , Estudios Retrospectivos , Encuestas y Cuestionarios
6.
Anal Chem ; 88(17): 8396-403, 2016 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-27505037

RESUMEN

Direct in-droplet (in stillo) microreaction monitoring using acoustically levitated micro droplets has been achieved by combining acoustic (ultrasonic) levitation for the first time with real time ambient tandem mass spectrometry (MS/MS). The acoustic levitation and inherent mixing of microliter volumes of reactants (3 µL droplets), yielding total reaction volumes of 6 µL, supported monitoring the acid-catalyzed degradation reaction of erythromycin A. This reaction was chosen to demonstrate the proof-of-principle of directly monitoring in stillo microreactions via hyphenated acoustic levitation and ambient ionization mass spectrometry. The microreactions took place completely in stillo over 30, 60, and 120 s within the containerless stable central pressure node of an acoustic levitator, thus readily promoting reaction miniaturization. For the evaluation of the miniaturized in stillo reactions, the degradation reactions were also carried out in vials (in vitro) with a total reaction volume of 400 µL. The reacted in vitro mixtures (6 µL total) were similarly introduced into the acoustic levitator prior to ambient ionization MS/MS analysis. The in stillo miniaturized reactions provided immediate real-time snap-shots of the degradation process for more accurate reaction monitoring and used a fraction of the reactants, while the larger scale in vitro reactions only yielded general reaction information.

7.
J Appl Clin Med Phys ; 17(4): 291-306, 2016 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-27455490

RESUMEN

The study purpose was to develop and validate a quality assurance test for CT automatic exposure control (AEC) systems based on a set of nested polymethylmethacrylate CTDI phantoms. The test phantom was created by offsetting the 16 cm head phantom within the 32 cm body annulus, thus creating a three part phantom. This was scanned at all acceptance, routine, and some nonroutine quality assurance visits over a period of 45 months, resulting in 115 separate AEC tests on scanners from four manufacturers. For each scan the longitudinal mA modulation pattern was generated and measurements of image noise were made in two annular regions of interest. The scanner displayed CTDIvol and DLP were also recorded. The impact of a range of AEC configurations on dose and image quality were assessed at acceptance testing. For systems that were tested more than once, the percentage of CTDIvol values exceeding 5%, 10%, and 15% deviation from baseline was 23.4%, 12.6%, and 8.1% respectively. Similarly, for the image noise data, deviations greater than 2%, 5%, and 10% from baseline were 26.5%, 5.9%, and 2%, respectively. The majority of CTDIvol and noise deviations greater than 15% and 5%, respectively, could be explained by incorrect phantom setup or protocol selection. Barring these results, CTDIvol deviations of greater than 15% from baseline were found in 0.9% of tests and noise deviations greater than 5% from baseline were found in 1% of tests. The phantom was shown to be sensitive to changes in AEC setup, including the use of 3D, longitudinal or rotational tube current modulation. This test methodology allows for continuing performance assessment of CT AEC systems, and we recommend that this test should become part of routine CT quality assurance programs. Tolerances of ± 15% for CTDIvol and ± 5% for image noise relative to baseline values should be used.


Asunto(s)
Cabeza/diagnóstico por imagen , Fantasmas de Imagen , Garantía de la Calidad de Atención de Salud/normas , Protección Radiológica/instrumentación , Protección Radiológica/normas , Tomografía Computarizada por Rayos X/instrumentación , Tomografía Computarizada por Rayos X/normas , Humanos , Dosis de Radiación , Interpretación de Imagen Radiográfica Asistida por Computador/normas , Tomógrafos Computarizados por Rayos X/normas
8.
J Emerg Med ; 51(5): 595-604, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27595372

RESUMEN

BACKGROUND: Case management is an effective short-term means to reduce Emergency Department (ED) visits in frequent users of the ED. OBJECTIVES: Our study aimed to assess the long-term efficacy of intensive case management in frequent users of the ED. METHODS: This was an observational study of ED usage conducted at a community hospital that has an ED case management program in which frequent users of the ED are enrolled and provided with intensive care management to reduce ED use. RESULTS: We identified 199 patients that were enrolled for 6 or more years. Patients averaged 16 visits per person per year in the year prior to enrollment. Patients averaged the following number of visits per person per year after enrollment: year 1 (7.1), year 2 (4.1), year 3 (3.1), year 4 (3.3), year 5 (3.1), year 6 (2.0), year 7 (2.1), and year 8 (1.9), all statistically significant compared to the year prior to enrollment. Twenty-nine patients, despite case management, continued their frequent use, and required a revision to their plan of care. Five patients required a second revision to their plan of care secondary to recurrent ED usage. Persistent use despite case management was primarily due to prescription medication misuse and chronic pain. CONCLUSION: Case management of ED frequent users seems to be an effective means to reduce ED usage in both the short and long term. Patients with prescription drug misuse or chronic pain may continue to demonstrate frequent use despite case management, and may require revisions to their plan of care.


Asunto(s)
Manejo de Caso/normas , Servicio de Urgencia en Hospital/estadística & datos numéricos , Servicio de Urgencia en Hospital/tendencias , Planificación de Atención al Paciente/tendencias , Adulto , Anciano , Manejo de Caso/estadística & datos numéricos , Servicio de Urgencia en Hospital/organización & administración , Femenino , Humanos , Masculino , Persona de Mediana Edad
10.
Eur J Mass Spectrom (Chichester) ; 20(2): 199-205, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24895781

RESUMEN

Chemical compositions of volatile and semi-volatile components in green and fermented leaves of Bergenia crassifolia L. were studied. Leaf components were identified using gas chromatography with low resolution mass spectrometry and direct analysis in real time (DART) high resolution mass spectrometry with an ID-CUBE ion source. Phytol, nerolidol, geraniol, linalool, alpha-bisabolol, alpha-bisabololoxide B, alpha-cadinol, delta-cadinene, alpha-terpineol and several other marker compounds of special interest were defined, for which the process of fermentation significantly changed their content in the leaves. Low resolution El GC-MS and ID-CUBE DART-HRMS were found to be complementary methods, as they provide different information, helpful to increase the confidence of identification.


Asunto(s)
Algoritmos , Análisis de los Alimentos/métodos , Cromatografía de Gases y Espectrometría de Masas/métodos , Hojas de la Planta/química , Saxifragaceae/química , Compuestos Orgánicos Volátiles/análisis , Color , Sistemas de Computación , Fermentación
11.
J Med Internet Res ; 16(12): e288, 2014 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-25499427

RESUMEN

BACKGROUND: Social media can be particularly useful for patients or families affected by rare conditions by allowing individuals to form online communities across the world. OBJECTIVE: Our aim in this study was to conduct a descriptive and quantitative analysis of the use of a social media community for Hirschsprung's Disease (HD). METHODS: In July 2011, a mother of a child with HD launched the "Shit Happens" campaign. The campaign uses social media (blogs, Twitter, and Facebook) to engage other families affected by HD. Internet analytics including Google Analytics and Facebook Insights were used to evaluate the reach and responsiveness of this campaign. RESULTS: On the day the HD campaign was launched, 387 people viewed the blog "Roo's Journey". Blog views have now exceeded 5400 views from 37 countries. The Facebook page extends to 46 countries, has an average post reach of 298 users, 1414 "likes", and an overall reach of 131,032 users. The campaign has 135 Twitter followers and 344 tweets at the time of writing. The most common question posted on the Facebook page is related to treatment for extreme diaper rash. Responsiveness assessment demonstrated that within 2 hours of posting, a question could receive 143 views and 20 responses, increasing to 30 responses after 5 hours. CONCLUSIONS: Social media networks are well suited to discussion, support, and advocacy for health-related conditions and can be especially important in connecting families affected by rare conditions. The HD campaign demonstrates the reach and responsiveness of a community that primarily relies on social media to connect families affected by HD. Although responsive, this community is currently lacking consistent access to evidence-based guidance for their common concerns. We will explore innovative consumer-researcher partnerships to offer a solution in future research.


Asunto(s)
Comunicación en Salud/métodos , Enfermedad de Hirschsprung/psicología , Internet , Medios de Comunicación Sociales , Adulto , Niño , Femenino , Humanos , Masculino , Padres , Red Social
12.
J Am Coll Health ; : 1-9, 2023 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-37399535

RESUMEN

Objective: This exploratory study examined campus attitudes toward vaccines to guide subsequent development of context-relevant interventions for increasing vaccine acceptance and uptake. Participants: We gathered ethnographic data on a convenience sample of campus community members (students, faculty, staff) at a public university over six weeks in spring 2022. Methods: Student researchers conducted a rapid ethnographic assessment across campus locations. Weekly team debriefs enabled ongoing, iterative refinement of instruments and supplemented observational fieldnotes. Data analysis was inductive and oriented toward practical recommendations for intervention development. Results: Four themes, and attendant recommendations, emerged: 1) social identities and social roles influence health-related beliefs, including vaccination; 2) vaccine knowledge influences vaccination behaviors; 3) language surrounding vaccines (sometimes) matters; 4) vaccines aren't considered part of general health and wellness and can't be forced. Conclusions: Findings highlight the need to address individual, social, and institutional contexts when designing campus-based behavioral interventions for vaccine uptake.

13.
Front Bioeng Biotechnol ; 11: 1240281, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37560539

RESUMEN

High-containment laboratories (HCLs) conduct critical research on infectious diseases, provide diagnostic services, and produce vaccines for the world's most dangerous pathogens, often called high-consequence pathogens (HCPs). The modernization of HCLs has led to an increasingly cyber-connected laboratory infrastructure. The unique cyberphysical elements of these laboratories and the critical data they generate pose cybersecurity concerns specific to these laboratories. Cyberbiosecurity, the discipline devoted to the study of cybersecurity risks in conjunction with biological risks, is a relatively new field for which few approaches have been developed to identify, assess, and mitigate cyber risks in biological research and diagnostic environments. This study provides a novel approach for cybersecurity risk assessment and identification of risk mitigation measures by applying an asset-impact analysis to the unique environment of HCLs. First, we identified the common cyber and cyberphysical systems in HCLs, summarizing the typical cyber-workflow. We then analyzed the potential adverse outcomes arising from a compromise of these cyber and cyberphysical systems, broadly categorizing potential consequences as relevant to scientific advancement, public health, worker safety, security, and the financial wellbeing of these laboratories. Finally, we discussed potential risk mitigation strategies, leaning heavily on the cybersecurity materials produced by the Center for Internet Security (CIS), including the CIS Controls®, that can serve as a guide for HCL operators to begin the process of implementing risk mitigation measures to reduce their cyberbiorisk and considering the integration of cyber risk management into existing biorisk management practices. This paper provides a discussion to raise awareness among laboratory decision-makers of these critical risks to safety and security within HCLs. Furthermore, this paper can serve as a guide for evaluating cyberbiorisks specific to a laboratory by identifying cyber-connected assets and the impacts associated with a compromise of those assets.

14.
Br Dent J ; 234(9): 661-667, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37173483

RESUMEN

Missing maxillary central incisors can impact a patient's psychological wellbeing and smile aesthetics. Comprehensive management of such cases requires a multidisciplinary team approach, often involving orthodontic, paediatric and restorative dental teams. This paper summarises the various management options for these complex patients.


Asunto(s)
Estética Dental , Incisivo , Humanos , Adolescente , Niño , Sonrisa , Maxilar
15.
Rapid Commun Mass Spectrom ; 26(11): 1329-37, 2012 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-22555926

RESUMEN

RATIONALE: Bergenia crassifolia is a plant widely used in herbal medicine. Its chemical composition has been little studied, and no studies using high-resolution mass spectrometry (HRMS) have been performed. Its phenolic components are of particular interest, due to the interest in such compounds in medicine and cosmetics. The ID-CUBE, a simplified Direct Analysis in Real Time (DART) ion source, suitable for the fast MS analysis of liquids without complex sample preparation, offers a new method of studying extracts of such plant. Coupling the ID-CUBE with a high-resolution mass spectrometer can provide identification of extract components. METHODS: Mass spectral conditions were optimized for model solutions of the flavonoid naringenin and used for the identification of phenolic compounds in green leaves extracts of Bergenia crassifolia. OpenSpot sample cards with a metal grid surface were used for sample introduction into the ID-CUBE ion source on an Obitrap mass spectrometer. The samples were applied as 5-µL aliquots of the extract onto the metal grid of the card. Sample ionization was stimulated in the ion source within 20 s by applying an electric current to the metal grid to thermally desorb the analytes into the gas flow of metastable helium atoms from the ID-CUBE. RESULTS: Elemental compositions were assigned to abundant ions in the mass spectra of the extracts. The major phenolic components were confirmed by their [M-H](-) ions. Thirty-six other marker ions were found, and elemental compositions were suggested for 30% of them, based on a search for compounds found in herbal extracts. CONCLUSIONS: The ID-CUBE-Orbitrap MS coupling allowed the rapid accurate mass determination of the phenolic components (and other compounds) in herbal extracts. Higher confidence in component identification could be provided by using additional structural elucidation methods, including tandem mass spectrometry (MS/MS), and this will be the focus of future studies.


Asunto(s)
Espectrometría de Masas/métodos , Fenoles/química , Extractos Vegetales/química , Saxifragaceae/química , Arbutina/química , Ácido Elágico/química , Flavanonas/química , Ácido Gálico/química , Hidroquinonas/química , Fenoles/clasificación , Fenoles/aislamiento & purificación , Hojas de la Planta/química
16.
Anal Bioanal Chem ; 403(10): 2807-12, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22362280

RESUMEN

Rapid screening of pesticides present on the surfaces of fruits and vegetables has been facilitated by using a Direct Analysis in Real Time (DART(®)) open air surface desorption ionization source coupled to an Exactive(®) high-resolution accurate mass benchtop orbitrap mass spectrometer. The use of cotton and polyester cleaning swabs to collect and retain pesticides for subsequent open air desorption ionization is demonstrated by sampling the surface of various produce to which solutions of pesticides have been applied at levels 10 and 100 times below the tolerance levels established by the United States Environmental Protection Agency (US EPA). Samples analyzed include cherry tomatoes, oranges, peaches and carrots each chosen for their surface characteristics which include: smooth, pitted, fuzzy, and rough respectively. Results from the direct analysis of fungicides on store-bought oranges are also described. In all cases, the swabs were introduced directly into the heated ionizing gas of the DART source resulting in production of protonated pesticide molecules within seconds of sampling. Operation of the orbitrap mass spectrometer at 25,000 full-width half maximum resolution was sufficient to generate high-quality accurate mass data. Stable external mass calibration eliminated the need for addition of standards typically required for mass calibration, thus allowing multiple analyses to be completed without instrument recalibration.


Asunto(s)
Análisis de los Alimentos/métodos , Frutas/química , Espectrometría de Masas/instrumentación , Plaguicidas/análisis , Verduras/química , Factores de Tiempo
17.
Rapid Commun Mass Spectrom ; 25(17): 2384-8, 2011 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-21793067

RESUMEN

Rapid vaporization of sample into the ionizing gas exiting a direct analysis in real time (DART®) source has been enabled by directing a high electrical current through a metal wire screen to which sample has been applied. This direct heating of the screen enables rapid vaporization of sample as the wire temperature rises from room temperature to greater than 400°C in less than 20 s. Positioning the screen between the DART source and atmospheric pressure inlet of the mass spectrometer ensures that the ionizing gas is in close proximity to the sample molecules, resulting in efficient ionization while significantly reducing the time required for mass spectrometric analysis. The capability to modulate the electrical current flow through the wires facilitates either rapid desorption for the determination of single component samples or slower desorption where analysis of mixtures might be desired. The technology also enables deployment of strategies for the determination of chemicals present as powders that might otherwise require dissolution prior to analysis. Results from the use of this thermally assisted DART ('TA-DART') system for the analysis of pure compounds, simple mixtures, solids and low vapor pressure samples are presented.

19.
Anal Chem ; 81(1): 193-202, 2009 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-19117450

RESUMEN

Two key bottlenecks in pharmaceutical bioanalysis are sample cleanup and chromatographic separations. Although multiple approaches have been developed in the past decade to either shorten or multiplex these steps, they remain the rate limiting steps as ADME (Absorption, Distribution, Metabolism, and Excretion) property screening is being routinely incorporated into the drug discovery process. In this work, a novel system incorporating an automated Direct Analysis in Real Time (DART) ionization source coupled with a triple-quadrupole mass spectrometer has been developed and evaluated for quantitative bioanalysis. This system has the capability of directly analyzing samples from their biological matrixes and therefore potentially eliminating the need for sample cleanup and chromatographic separations. A LEAP Technologies autosampler was customized to perform the automated sample introduction into the DART beam with high precision, which significantly improved the reproducibility of the method. Additional pumping was applied to the atmospheric pressure inlet on the mass spectrometer to compensate for the increased vacuum load because of the use of high-flow helium by the DART. This resulted in an improvement of detection sensitivity by a factor of 10 to 100 times. Matrix effects for a diversified class of compounds were evaluated directly from untreated raw plasma and were found to range from approximately 0.05 to 0.7. Precision and accuracy were also tested for multiple test compounds over a dynamic range of four orders of magnitude. The system has been used to analyze biological samples from both in vivo pharmacokinetic studies and in vitro microsomal/S9 stability studies, and the results generated were similar to those obtained with conventional LC/MS/MS methods. Overall, this new automated DART-triple quadrupole mass spectrometer system has demonstrated significant potential for high-throughput bioanalysis.


Asunto(s)
Espectrometría de Masas/métodos , Preparaciones Farmacéuticas/análisis , Animales , Humanos , Ratones , Preparaciones Farmacéuticas/sangre , Ratas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Verapamilo/sangre
20.
Learn Individ Differ ; 18(3): 308-315, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-22224065

RESUMEN

A core assumption of response to instruction or intervention (RTI) models is the importance of measuring growth in achievement over time in response to effective instruction or intervention. Many RTI models actively monitor growth for identifying individuals who need different levels of intervention. A large-scale (N=23,438), two-year longitudinal study of first grade children was carried out to compare the predictive validity of measures of achievement status, growth in achievement, and their combination for predicting future reading achievement. The results indicate that under typical conditions, measures of growth do not make a contribution to prediction that is independent of measures of achievement status. These results question the validity of a core assumption of RTI models.

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