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1.
Psychol Med ; 53(6): 2418-2426, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-34629132

RESUMEN

BACKGROUND: The prevalence of serious psychological distress (SPD) was elevated during the COVID-19 pandemic in the USA, but the relationships of SPD during the pandemic with pre-pandemic SPD, pre-pandemic socioeconomic status, and pandemic-related social stressors remain unexamined. METHODS: A probability-based sample (N = 1751) of the US population age 20 and over was followed prospectively from February 2019 (T1), with subsequent interviews in May 2020 (T2) and August 2020 (T3). Multinomial logistic regression was used to assess prospective relationships between T1 SPD with experiences of disruption of employment, health care, and childcare at T2. Binary logistic regression was then used to assess relationships of T1 SPD, and socioeconomic status and T2 pandemic-related stressors with T3 SPD. RESULTS: At T1, SPD was associated with age, race/ethnicity, and household income. SPD at T1 predicted disruption of employment (OR 4.5, 95% CI 1.4-3.8) and health care (OR 3.2, 95% CI 1.4-7.1) at T2. SPD at T1 (OR 10.2, 95% CI 4.5-23.3), low household income at T1 (OR 2.6, 95% CI 1.1-6.4), disruption of employment at T2 (OR 3.2, 95% CI 1.4-7.6), and disruption of healthcare at T2 (OR 3.3, 95% CI 1.5-7.2) were all significantly associated with elevated risk for SPD at T3. CONCLUSIONS: Elevated risk for SPD during the COVID-19 pandemic is related to multiple psychological and social pathways that are likely to interact over the life course. Policies and interventions that target individuals with pre-existing mental health conditions as well as those experiencing persistent unemployment should be high priorities in the mental health response to the pandemic.


Asunto(s)
COVID-19 , Distrés Psicológico , Humanos , Adulto Joven , Adulto , Pandemias , Estudios Longitudinales , COVID-19/epidemiología , Estudios Prospectivos , Estrés Psicológico/epidemiología , Estrés Psicológico/psicología
2.
Health Econ ; 31(9): 1844-1861, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35751857

RESUMEN

While psychological distress is a common sequelae of job loss, how that relationship continued during the COVID-19 pandemic is unclear, for example, given higher health risk to working due to disease exposure. This paper examines changes in psychological distress depending on job loss among a cohort of randomly selected residents living in nine predominantly African American low-income neighborhoods in Pittsburgh PA across four waves between 2013 and 2020. Between 2013 and 2016, we found an increase in psychological distress after job loss in line with the literature. In contrast, between 2018 and 2020 we found change in psychological distress did not differ by employment loss. However, residents who had financial concerns and lost their jobs had the largest increases in psychological distress, while residents who did not have serious financial concerns-potentially due to public assistance-but experienced job loss had no increase in distress, a better outcome even than those that retained their jobs. Using partial identification, we find job loss during the pandemic decreased psychological distress for those without serious financial concerns. This has important policy implications for how high-risk persons within low-income communities are identified and supported, as well as what type of public assistance may help.


Asunto(s)
COVID-19 , Distrés Psicológico , Negro o Afroamericano/psicología , Humanos , Pandemias , Estrés Psicológico/epidemiología , Estrés Psicológico/psicología
3.
Am J Epidemiol ; 190(5): 798-806, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33047782

RESUMEN

Neighborhood socioeconomic conditions (NSECs) are associated with resident diet, but most research has been cross-sectional. We capitalized on a natural experiment in Pittsburgh, Pennsylvania, in which 1 neighborhood experienced substantial investments and a sociodemographically similar neighborhood that did not, to examine pathways from neighborhood investments to changed NSECs and changed dietary behavior. We examined differences between renters and homeowners. Data were from a random sample of households (n = 831) in each of these low-income Pittsburgh neighborhoods that were surveyed in 2011 and 2014. Structural equation modeling tested direct and indirect pathways from neighborhood to resident dietary quality, adjusting for individual-level sociodemographics, with multigroup testing by homeowners versus renters. Neighborhood investments were directly associated with improved dietary quality for renters (ß = 0.27, 95% confidence interval (CI): 0.05, 0.50) and homeowners (ß = 0.51, 95% CI: 0.10, 0.92). Among renters, investments also were associated with dietary quality through a positive association with commercial prices (ß = 0.34, 95% CI: 0.15, 0.54) and a negative association with residential prices (ß = -0.30, 95% CI: -0.59, -0.004). Among homeowners, we did not observe any indirect pathways from investments to dietary quality through tested mediators. Investing in neighborhoods may support resident diet through improvements in neighborhood commercial environments for renters, but mechanisms appear to differ for homeowners.


Asunto(s)
Negro o Afroamericano , Dieta Saludable/etnología , Propiedad , Características de la Residencia , Adulto , Anciano , Anciano de 80 o más Años , Índice de Masa Corporal , Femenino , Inseguridad Alimentaria , Humanos , Masculino , Recuerdo Mental , Persona de Mediana Edad , Modelos Estadísticos , Pennsylvania , Áreas de Pobreza , Factores Socioeconómicos
4.
Anal Chem ; 93(8): 4015-4022, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33587599

RESUMEN

Life was originally assumed to utilize the l-amino acids only. Since 1980s, the d-amino acid-containing peptides (DAACPs) were detected in animals, often at extremely low levels with tremendous functional specificity. As the unguided proteomic algorithms based on peptide masses are oblivious to DAACPs, many more are believed to be hidden in organisms and novel methods to tackle DAACPs are sought. Linear ion mobility spectrometry (IMS) can distinguish and characterize the d/l-epimers but is restricted by poor orthogonality to MS as in other contexts. We now bring to this area the newer technique of differential IMS (FAIMS). The orthogonality of MS to high-resolution FAIMS exceeded that to linear IMS by 6×, the greatest factor found for biomolecules so far. Hence, FAIMS has achieved the 2.5× resolution of trapped IMS on average despite a lower resolving power, fully separating all 18 pairs of representative epimer species with masses of ∼400-5,000 Da and charge states of 1-6. A constant isomer resolution over these ranges allows projecting success for yet larger DAACPs.


Asunto(s)
Péptidos , Proteómica , Aminoácidos , Animales , Espectrometría de Movilidad Iónica , Espectrometría de Masas
5.
Am J Public Health ; 111(3): 494-497, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33476228

RESUMEN

Objectives. To examine the impact of COVID-19 shutdowns on food insecurity among a predominantly African American cohort residing in low-income racially isolated neighborhoods.Methods. Residents of 2 low-income African American food desert neighborhoods in Pittsburgh, Pennsylvania, were surveyed from March 23 to May 22, 2020, drawing on a longitudinal cohort (n = 605) previously followed from 2011 to 2018. We examined longitudinal trends in food insecurity from 2011 to 2020 and compared them with national trends. We also assessed use of food assistance in our sample in 2018 versus 2020.Results. From 2018 to 2020, food insecurity increased from 20.7% to 36.9% (t = 7.63; P < .001) after steady declines since 2011. As a result of COVID-19, the United States has experienced a 60% increase in food insecurity, whereas this sample showed a nearly 80% increase, widening a preexisting disparity. Participation in the Supplemental Nutrition Assistance Program (52.2%) and food bank use (35.9%) did not change significantly during the early weeks of the pandemic.Conclusions. Longitudinal data highlight profound inequities that have been exacerbated by COVID-19. Existing policies appear inadequate to address the widening gap.


Asunto(s)
Negro o Afroamericano/estadística & datos numéricos , COVID-19/epidemiología , Inseguridad Alimentaria , Pobreza/estadística & datos numéricos , Humanos , Estudios Longitudinales , Pandemias , Pennsylvania/epidemiología , Características de la Residencia/estadística & datos numéricos , Factores de Riesgo , SARS-CoV-2 , Estados Unidos/epidemiología
6.
Prev Med ; 143: 106362, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33388325

RESUMEN

The COVID-19 pandemic has caused financial stress and disrupted daily life more quickly than any prior economic downturn and on a scale beyond any prior natural disaster. This study aimed to assess the impact of the pandemic on psychological distress and identify vulnerable groups using longitudinal data to account for pre-pandemic mental health status. Clinically significant psychological distress was assessed with the Kessler-6 in a national probability sample of adults in the United States at two time points, February 2019 (T1) and May 2020 (T2). To identify increases in distress, psychological distress during the worst month of the past year at T1 was compared with psychological distress over the past 30-days at T2. Survey adjusted logistic regression was used to estimate associations of demographic characteristics at T1 (gender, age, race, and income) and census region at T2 with within-person increases in psychological distress. The past-month prevalence of serious psychological distress at T2 was as high as the past-year prevalence at T1 (10.9% vs. 10.2%). Psychological distress was strongly associated across assessments (X2(4) = 174.6, p < .0001). Increase in psychological distress above T1 was associated with gender, age, household income, and census region. Equal numbers of people experienced serious psychological distress in 30-days during the pandemic as did over an entire year prior to the pandemic. Mental health services and research efforts should be targeted to those with a history of mental health conditions and groups identified as at high risk for increases in distress above pre-pandemic levels.


Asunto(s)
COVID-19/epidemiología , COVID-19/psicología , Trastornos Mentales/epidemiología , Pandemias/estadística & datos numéricos , Distrés Psicológico , Estrés Psicológico/epidemiología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , SARS-CoV-2 , Encuestas y Cuestionarios , Factores de Tiempo , Estados Unidos/epidemiología , Adulto Joven
7.
Anal Chem ; 92(3): 2364-2368, 2020 02 04.
Artículo en Inglés | MEDLINE | ID: mdl-31935065

RESUMEN

Biological functions of many proteins are governed by post-translational modifications (PTMs). In particular, the rich PTM complement in histones controls the gene expression and chromatin structure with major health implications via a combinatoric language. Deciphering that "histone code" is the great challenge for proteomics given an astounding number of possible proteoforms, including isomers with different PTM positions. These must be disentangled on the top- or middle-down level to preserve the key PTM connectivity, which condensed-phase separations failed to achieve. We reported the capability of ion mobility spectrometry (IMS) methods to resolve such isomers for model histone tails. Here, we advance to biological samples, showing middle-down analyses of histones from mouse embryonic stem cells via online chromatography to fractionate proteoforms with distinct PTM sets, differential or field asymmetric waveform IMS (FAIMS) to resolve the isomers, and Orbitrap mass spectrometry with electron transfer dissociation to identify the resolved species.


Asunto(s)
Histonas/análisis , Proteómica , Animales , Células Madre Embrionarias/citología , Espectrometría de Movilidad Iónica , Ratones
8.
Hous Policy Debate ; 30(2): 164-190, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33013148

RESUMEN

During the 1990s, the U.S. Department of Housing and Urban Development awarded more than $6 billion in competitive grants called HOPE VI to spur neighborhood redevelopment. We add to HOPE VI research by examining the impacts of a large set of public-private real estate investments, including HOPE VI, made over a 16-year period in a distressed Pittsburgh neighborhood called the Hill District. Specifically, we estimate the effects of the $468 million additional public-private investments that Hill District received compared to a demographically similar neighborhood on sale prices, rental prices, and crime. We find large and statistically significant impacts of the public-private investments on residential sales prices, commercial sales prices, and on rental prices, but only a marginally significant yet meaningful decline in non-violent arrests. For each additional $10 million of public-private investment, we find a 0.95 percent increase in residential sales prices, 2.7 percent increase in commercial sales prices, and 0.55 percent increase in rental prices. Because there was an accumulated difference over 16 years of $468 million in the amount of public-private investment across the two neighborhoods we examine, these percentage increases amount to large changes in real estate prices over that time. Commercial real estate investors and homeowners benefited the most, followed by residential landlords. Our analyses imply cities should anticipate the potential impacts of major neighborhood investment on low-income households, especially unsubsidized renters that most directly experience the brunt of rising rents.

9.
Anal Chem ; 91(5): 3687-3693, 2019 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-30707550

RESUMEN

Nearly all molecules incorporate at least one element with stable isotopes, yielding ubiquitous isotopologic envelopes in mass spectra. Those envelopes split in differential or field asymmetric waveform ion mobility (FAIMS) spectra depending on the ion geometry, enabling a new general approach to isomer delineation as we demonstrated for chloroanilines. Here, we report that analogous bromoanilines exhibit qualitatively distinct isotopic shifts under identical conditions, some changing signs depending on the gas. This dramatic elemental specificity conveys the breadth and diversity of structural isotopic effect in FAIMS, suggesting unique information-rich patterns for compounds involving various elements and feasibility of enhancing the structural elucidation by atom substitution. We also introduce the capability to make or ensure structural assignments employing major isomer-specific peak broadening due to unresolved isotopomer mixtures.

10.
Anal Chem ; 91(2): 1479-1485, 2019 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-30543404

RESUMEN

Strong orthogonality to mass spectrometry makes differential ion mobility spectrometry (FAIMS) a powerful tool for isomer separations. However, high FAIMS resolution has been achieved overall only with buffers rich in He or H2. That obstructed coupling to Fourier transform mass spectrometers operating under ultrahigh vacuum, but exceptional m/ z resolution and accuracy of FTMS are indispensable for frontline biological and environmental applications. By raising the waveform amplitude to 6 kV, we enabled high FAIMS resolution using solely N2 and thus straightforward integration with any MS platform: here Orbitrap XL with the electron transfer dissociation (ETD) option. The initial evaluation for complete histone tails (50 residues) with diverse post-translational modifications on alternative sites demonstrates a broad capability to separate and confidently identify the PTM localization variants in the middle-down range.

11.
Anal Chem ; 91(10): 6918-6925, 2019 05 21.
Artículo en Inglés | MEDLINE | ID: mdl-31034203

RESUMEN

Strong orthogonality between differential ion mobility spectrometry (FAIMS) and mass spectrometry (MS) makes their hybrid a powerful approach to separate isomers and isobars. Harnessing that power depends on high resolution in both dimensions. The ultimate mass resolution and accuracy are delivered by Fourier Transform MS increasingly realized in Orbitrap MS, whereas FAIMS resolution is generally maximized by buffers rich in He or H2 that elevate ion mobility and lead to prominent non-Blanc effects. However, turbomolecular pumps have lower efficiency for light gas molecules and their flow from the FAIMS stage complicates maintaining the ultrahigh vacuum (UHV) needed for Orbitrap operation. Here we address this challenge via two hardware modifications: (i) a differential pumping step between FAIMS and MS stages and (ii) reconfiguration of vacuum lines to isolate pumping of the high vacuum (HV) region. Either greatly ameliorates the pressure increases upon He or H2 aspiration. This development enables free optimization of FAIMS carrier gas without concerns about MS performance, maximizing the utility and flexibility of FAIMS/MS platforms.

12.
Med Care ; 57(5): 341-347, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30870391

RESUMEN

BACKGROUND: There is a significant geographic variation in anesthesia provider supply. Lower supply in rural communities raises concerns about access to procedures that require anesthesia in rural areas. State policies related to certified registered nurse anesthetist (CRNA) practice may help to alleviate rural supply concerns. OBJECTIVES: To estimate the association between state CRNA policy and anesthesia provider supply especially in rural communities. RESEARCH DESIGN: Repeated cross-sectional design using ordinary least squares and 2-stage least squares regressions. SUBJECTS: All counties in the United States from 2010 to 2015. MEASURES: Dependent variables include anesthesia provider counts per 100,000 people, calculated separately for anesthesiologists, CRNAs, and their sum. Key variables of interest include state-level CRNA policy based on scope of practice (SOP) regulations and Medicare opt-out status. RESULTS: Opt-out status and less restrictive SOP regulations were consistently correlated with a greater supply of CRNAs, especially in rural counties. Furthermore, we found that anesthesiologists and CRNAs tend to be complements to each other, but less restrictive SOP and opt-out status tend to weaken the importance of this relationship. CONCLUSIONS: State regulations may lead to increased supply of CRNAs in rural communities. However, the design of our study makes causality difficult to assert. So, it is also possible that states set CRNA policy as a response to counts of anesthesia providers in rural areas. Furthermore, given supply of anesthesiologists and CRNAs are complementary to one another, improving access to anesthesia services may require addressing issues pertaining to the supply of all anesthesia provider types.


Asunto(s)
Anestesiólogos/provisión & distribución , Política de Salud/legislación & jurisprudencia , Enfermeras Anestesistas/provisión & distribución , Servicios de Salud Rural/estadística & datos numéricos , Estudios Transversales , Humanos , Gobierno Estatal , Estados Unidos
13.
Clin J Sport Med ; 29(5): 426-429, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31460957

RESUMEN

OBJECTIVE: Sports ultrasound (US) is becoming popular in diagnosing musculoskeletal injuries. This study, also called the Pediatric Distal Radius Ultrasound Study (PeDRUS), compared the diagnostic accuracy of sports US with plain radiographs in possible distal radius buckle fractures in pediatric population. METHODS: In this prospective observational study, patients (2-15 years) presenting to an outpatient orthopedic injury clinic with distal forearm injuries without deformity were recruited. Bedside ultrasonography was performed and interpreted by the investigators as positive or negative for fracture. Plain radiographs were then performed and interpreted by the same investigator. The radiographs were considered the definitive imaging study for this investigation. RESULTS: Fifty-one patients were included with a mean age of 9.9 years. Fractures were diagnosed on both US and plain radiographs in 34 patients. Fractures were ruled out on both US and plain radiographs in 16 patients. There was only one case in which the US was interpreted differently than radiograph. For fractures of the distal radius in this population, the sensitivity was 97.1% [95% confidence interval (CI) = 89.2-97.1] and the specificity was 100% (95% CI = 82.5-100). The positive predictive value was 100% (95% CI = 91.8-100), whereas the negative predictive value was 94.1% (95% CI = 77.7-94.1). The positive likelihood ratio was infinite, suggesting utility in confirming a fracture. The negative likelihood ratio was 0.03 (95% CI = 0.03-0.13), suggesting that US has value in ruling out a fracture. CONCLUSIONS: Our study suggests that diagnostic sports US is sensitive and specific for detecting distal radius fractures in pediatric patients with nondeformed forearm injuries, demonstrating that US is an acceptable alternative to plain radiographs for evaluating fractures in a pediatric population.


Asunto(s)
Traumatismos en Atletas/diagnóstico por imagen , Fracturas del Radio/diagnóstico por imagen , Deportes Juveniles/lesiones , Adolescente , Niño , Preescolar , Servicio de Urgencia en Hospital , Humanos , Sistemas de Atención de Punto , Valor Predictivo de las Pruebas , Estudios Prospectivos , Radiografía , Ultrasonografía
14.
Anal Chem ; 90(15): 9410-9417, 2018 08 07.
Artículo en Inglés | MEDLINE | ID: mdl-29969234

RESUMEN

Nearly all molecules incorporate elements with stable isotopes. The resulting isotopologue envelopes in mass spectra tell the exact stoichiometry but nothing about the geometry. Chromatography and electrophoresis at high resolution also can distinguish isotopologues, again without revealing structural information. In high-definition differential ion mobility (FAIMS) spectra, these envelopes universally split in a structure-specific manner, providing a new general approach to isomer delineation. Here, we show that the peak shifts from instances of the same isotope are equal and can be averaged into characteristic elemental shifts, namely 13C and 37Cl for dichloroanilines (DCA). Matrices of these shifts, including the gas composition dimension, are unique to the structure. Hence, all six DCA isomers (with four making two unresolved pairs) are readily delineated in the 13C/37Cl maps with He/CO2 buffer gases. Mixtures of coeluting isomers are also distinguished from pure components.

15.
Anal Chem ; 90(1): 669-673, 2018 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-29220157

RESUMEN

Nearly all compounds comprise numerous isotopologues ensuing from stable natural isotopes for constituent elements. The consequent isotopic envelopes in mass spectra can reveal the ion stoichiometry but not geometry. We found those envelopes to split in differential ion mobility (FAIMS) spectra in a manner dependent on the ion geometry and buffer gas composition. The resulting multidimensional matrix of isotopic shifts is specific to isomers, providing a fundamentally new approach to the characterization of chemical structure. The physical origins of the effect remain to be clarified but likely ensue from the transposition of center of mass of the ion within its geometry frame affecting the partition of energy in above-thermal collisions between the translational and rotational degrees of freedom. The additivity of shifts, holding with no exception so far, may be the key to unraveling the foundations of observed behavior.

16.
Anal Chem ; 90(4): 2918-2925, 2018 02 20.
Artículo en Inglés | MEDLINE | ID: mdl-29359922

RESUMEN

Comprehensive characterization of proteomes comprising the same proteins with distinct post-translational modifications (PTMs) is a staggering challenge. Many such proteoforms are isomers (localization variants) that require separation followed by top-down or middle-down mass spectrometric analyses, but condensed-phase separations are ineffective in those size ranges. The variants for "middle-down" peptides were resolved by differential ion mobility spectrometry (FAIMS), relying on the mobility increment at high electric fields, but not previously by linear IMS on the basis of absolute mobility. We now use complete histone tails with diverse PTMs on alternative sites to demonstrate that high-resolution linear IMS, here trapped IMS (TIMS), broadly resolves the variants of ∼50 residues in full or into binary mixtures quantifiable by tandem MS, largely thanks to orthogonal separations across charge states. Separations using traveling-wave (TWIMS) and/or involving various time scales and electrospray ionization source conditions are similar (with lower resolution for TWIMS), showing the transferability of results across linear IMS instruments. The linear IMS and FAIMS dimensions are substantially orthogonal, suggesting FAIMS/IMS/MS as a powerful platform for proteoform analyses.


Asunto(s)
Histonas/aislamiento & purificación , Péptidos/aislamiento & purificación , Proteoma/aislamiento & purificación , Histonas/química , Histonas/metabolismo , Espectrometría de Masas , Péptidos/química , Péptidos/metabolismo , Procesamiento Proteico-Postraduccional , Proteoma/química , Proteoma/metabolismo
17.
Med Care ; 56(1): 25-30, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29189577

RESUMEN

BACKGROUND: Methodological differences between evaluations of medical home adoption might complicate readers' ability to draw conclusions across studies. OBJECTIVES: To study whether associations between medical home adoption and patient care are affected by methodological choices. DESIGN, SETTING, AND SUBJECTS: Among 71 practices participating in the Pennsylvania Chronic Care Initiative (a medical home pilot), we estimated cross-sectional and longitudinal associations between 4 definitions of "medical home adoption" [National Committee on Quality Assurance (NCQA) recognition in year 3, Medical Home Index scores at baseline and 3, and within-practice changes in Medical Home Index scores between baseline and year 3] and utilization and quality. MEASUREMENTS: Six utilization and 6 quality measures. RESULTS: In cross-sectional analyses at year 3, NCQA recognition was associated with higher rates of nephropathy monitoring (7.23 percentage points; confidence interval, 0.45-14.02), breast cancer screening (7.48; 2.11-12.86), and colorectal cancer screening (8.43; 2.44-14.42). In longitudinal analyses, NCQA recognition was associated with increases in hospitalization rates (2.75 per 1000 patient-months; 0.52-4.98). In baseline cross-sectional analyses, higher Medical Home Index scores were associated with fewer ambulatory care-sensitive hospitalizations (-0.61 per 1000 patient per month; -1.11 to -0.11), all-cause emergency department visits (-6.80; -12.28 to -1.32), and ambulatory care-sensitive emergency department visits (-5.60; 10.32 to -0.88). There were no statistically significant associations between any other measure of medical home adoption and quality or utilization. CONCLUSIONS: The findings of medical home evaluations are sensitive to methodological choices. Meta-analyses, narrative reviews, and other syntheses of medical home studies should consider subdividing their findings by analytic approach.


Asunto(s)
Hospitalización/estadística & datos numéricos , Atención Dirigida al Paciente/estadística & datos numéricos , Atención Dirigida al Paciente/normas , Garantía de la Calidad de Atención de Salud/métodos , Atención Ambulatoria/estadística & datos numéricos , Estudios Transversales , Servicio de Urgencia en Hospital/estadística & datos numéricos , Humanos , Estudios Longitudinales , Pennsylvania
18.
Anal Chem ; 89(21): 11787-11794, 2017 11 07.
Artículo en Inglés | MEDLINE | ID: mdl-28982001

RESUMEN

Despite often minute concentrations in vivo, d-amino acid containing peptides (DAACPs) are crucial to many life processes. Standard proteomics protocols fail to detect them as d/l substitutions do not affect the peptide parent and fragment masses. The differences in fragment yields are often limited, obstructing the investigations of important but low abundance epimers in isomeric mixtures. Separation of d/l-peptides using ion mobility spectrometry (IMS) was impeded by small collision cross section differences (commonly ∼1%). Here, broad baseline separation of DAACPs with up to ∼30 residues employing trapped IMS with resolving power up to ∼340, followed by time-of-flight mass spectrometry is demonstrated. The d/l-pairs coeluting in one charge state were resolved in another, and epimers merged as protonated species were resolved upon metalation, effectively turning the charge state and cationization mode into extra separation dimensions. Linear quantification down to 0.25% proved the utility of high resolution IMS-MS for real samples with large interisomeric dynamic range. Very close relative mobilities found for DAACP pairs using traveling-wave IMS (TWIMS) with different ion sources and faster IMS separations showed the transferability of results across IMS platforms. Fragmentation of epimers can enhance their identification and further improve detection and quantification limits, and we demonstrate the advantages of online mobility separated collision-induced dissociation (CID) followed by high resolution mass spectrometry (TIMS-CID-MS) for epimer analysis.


Asunto(s)
Aminoácidos/química , Espectrometría de Movilidad Iónica/métodos , Espectrometría de Masas/métodos , Péptidos/química , Péptidos/aislamiento & purificación , Protones , Estereoisomerismo , Factores de Tiempo
19.
Anal Chem ; 89(10): 5461-5466, 2017 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-28406606

RESUMEN

Histone proteins are subject to dynamic post-translational modifications (PTMs) that cooperatively modulate the chromatin structure and function. Nearly all functional PTMs are found on the N-terminal histone domains (tails) of ∼50 residues protruding from the nucleosome core. Using high-definition differential ion mobility spectrometry (FAIMS) with electron transfer dissociation, we demonstrate rapid baseline gas-phase separation and identification of tails involving monomethylation, trimethylation, acetylation, or phosphorylation in biologically relevant positions. These are by far the largest variant peptides resolved by any method, some with PTM contributing just 0.25% to the mass. This opens the door to similar separations for intact proteins and in top-down proteomics.


Asunto(s)
Histonas/metabolismo , Espectrometría de Movilidad Iónica/métodos , Péptidos/análisis , Acetilación , Secuencia de Aminoácidos , Histonas/química , Metilación , Péptidos/síntesis química , Fosforilación , Proteómica
20.
Conserv Biol ; 31(6): 1257-1270, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29030915

RESUMEN

Political and economic transitions have had substantial impacts on forest conservation. Where transitions are underway or anticipated, historical precedent and methods for systematically assessing future trends should be used to anticipate likely threats to forest conservation and design appropriate and prescient policy measures to counteract them. Myanmar is transitioning from an authoritarian, centralized state with a highly regulated economy to a more decentralized and economically liberal democracy and is working to end a long-running civil war. With these transitions in mind, we used a horizon-scanning approach to assess the 40 emerging issues most affecting Myanmar's forests, including internal conflict, land-tenure insecurity, large-scale agricultural development, demise of state timber enterprises, shortfalls in government revenue and capacity, and opening of new deforestation frontiers with new roads, mines, and hydroelectric dams. Averting these threats will require, for example, overhauling governance models, building capacity, improving infrastructure- and energy-project planning, and reforming land-tenure and environmental-protection laws. Although challenges to conservation in Myanmar are daunting, the political transition offers an opportunity for conservationists and researchers to help shape a future that enhances Myanmar's social, economic, and environmental potential while learning and applying lessons from other countries. Our approach and results are relevant to other countries undergoing similar transitions.


Asunto(s)
Conservación de los Recursos Naturales/legislación & jurisprudencia , Agricultura Forestal/legislación & jurisprudencia , Bosques , Política , Biodiversidad , Mianmar
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