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1.
J Public Health Manag Pract ; 30(1): 72-78, 2024.
Article in English | MEDLINE | ID: mdl-37801028

ABSTRACT

CONTEXT: The Centers for Disease Control and Prevention (CDC) has a long history of using high-quality science to drive public health action that has improved the health, safety, and well-being of people in the United States and globally. To ensure scientific quality, manuscripts authored by CDC staff are required to undergo an internal review and approval process known as clearance. During 2022, CDC launched a scientific clearance transformation initiative to improve the efficiency of the clearance process while ensuring scientific quality. PROGRAM: As part of the scientific clearance transformation initiative, a group of senior scientists across CDC developed a framework called the Domains of Excellence for High-Quality Publications (DOE framework). The framework includes 7 areas ("domains") that authors can consider for developing high-quality and impactful scientific manuscripts: Clarity, Scientific Rigor, Public Health Relevance, Policy Content, Ethical Standards, Collaboration, and Health Equity. Each domain includes multiple quality elements, highlighting specific key considerations within. IMPLEMENTATION: CDC scientists are expected to use the DOE framework when conceptualizing, developing, revising, and reviewing scientific products to support collaboration and to ensure the quality and impact of their scientific manuscripts. DISCUSSION: The DOE framework sets expectations for a consistent standard for scientific manuscripts across CDC and promotes collaboration among authors, partners, and other subject matter experts. Many aspects have broad applicability to the public health field at large and might be relevant for others developing high-quality manuscripts in public health science. The framework can serve as a useful reference document for CDC authors and others in the public health community as they prepare scientific manuscripts for publication and dissemination.


Subject(s)
Health Equity , Public Health , Humans , United States , Centers for Disease Control and Prevention, U.S.
2.
Molecules ; 28(13)2023 Jun 22.
Article in English | MEDLINE | ID: mdl-37446594

ABSTRACT

NIR dyes have become popular for many applications, including biosensing and imaging. For this reason, the molecular switch mechanism of the xanthene dyes makes them useful for in vivo detection and imaging of bioanalytes. Our group has been designing NIR xanthene-based dyes by the donor-acceptor-donor approach; however, the equilibrium between their opened and closed forms varies depending on the donors and spacer. We synthesized donor-acceptor-donor NIR xanthene-based dyes with an alkyne spacer via the Sonogashira coupling reaction to investigate the effects of the alkyne spacer and the donors on the maximum absorption wavelength and the molecular switching (ring opening) process of the dyes. We evaluated the strength and nature of the donors and the presence and absence of the alkyne spacer on the properties of the dyes. It was shown that the alkyne spacer extended the conjugation of the dyes, leading to absorption wavelengths of longer values compared with the dyes without the alkyne group. In addition, strong charge transfer donors shifted the absorption wavelength towards the NIR region, while donors with strong π-donation resulted in xanthene dyes with a smaller equilibrium constant. DFT/TDDFT calculations corroborated the experimental data in most of the cases. Dye 2 containing the N,N-dimethylaniline group gave contrary results and is being further investigated.


Subject(s)
Alkynes , Coloring Agents , Benzopyrans , Xanthenes
3.
Angew Chem Int Ed Engl ; 62(13): e202214855, 2023 03 20.
Article in English | MEDLINE | ID: mdl-36722146

ABSTRACT

Shortwave infrared (SWIR) dyes are characterized by their ability to absorb light from 900 to 1400 nm, which is ideal for deep tissue imaging owing to minimized light scattering and interference from endogenous pigments. An approach to access such molecules is to tune the photophysical properties of known near-infrared dyes. Herein, we report the development of a series of easily accessible (three steps) SWIR xanthene dyes based on a dibenzazepine donor conjugated to thiophene (SCR-1), thienothiophene (SCR-2), or bithiophene (SCR-3). We leverage the fact that SCR-1 undergoes a bathochromic shift when aggregated for in vivo studies by developing a ratiometric nanoparticle for NO (rNP-NO), which we employed to successfully visualize pathological levels of nitric oxide in a drug-induced liver injury model via deep tissue SWIR photoacoustic (PA) imaging. Our work demonstrates how easily this dye series can be utilized as a component in nanosensor designs for imaging studies.


Subject(s)
Nitric Oxide , Photoacoustic Techniques , Photoacoustic Techniques/methods , Xanthenes , Diagnostic Imaging/methods , Fluorescent Dyes , Optical Imaging
4.
Clin Infect Dis ; 74(2): 319-326, 2022 01 29.
Article in English | MEDLINE | ID: mdl-33864375

ABSTRACT

BACKGROUND: To inform prevention strategies, we assessed the extent of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission and settings in which transmission occurred in a Georgia public school district. METHODS: During 1 December 2020-22 January 2021, SARS-CoV-2-infected index cases and their close contacts in schools were identified by school and public health officials. For in-school contacts, we assessed symptoms and offered SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR) testing; performed epidemiologic investigations and whole-genome sequencing to identify in-school transmission; and calculated secondary attack rate (SAR) by school setting (eg, sports, elementary school classroom), index case role (ie, staff, student), and index case symptomatic status. RESULTS: We identified 86 index cases and 1119 contacts, 688 (61.5%) of whom received testing. Fifty-nine of 679 (8.7%) contacts tested positive; 15 of 86 (17.4%) index cases resulted in ≥2 positive contacts. Among 55 persons testing positive with available symptom data, 31 (56.4%) were asymptomatic. Highest SARs were in indoor, high-contact sports settings (23.8% [95% confidence interval {CI}, 12.7%-33.3%]), staff meetings/lunches (18.2% [95% CI, 4.5%-31.8%]), and elementary school classrooms (9.5% [95% CI, 6.5%-12.5%]). The SAR was higher for staff (13.1% [95% CI, 9.0%-17.2%]) vs student index cases (5.8% [95% CI, 3.6%-8.0%]) and for symptomatic (10.9% [95% CI, 8.1%-13.9%]) vs asymptomatic index cases (3.0% [95% CI, 1.0%-5.5%]). CONCLUSIONS: Indoor sports may pose a risk to the safe operation of in-person learning. Preventing infection in staff members, through measures that include coronavirus disease 2019 vaccination, is critical to reducing in-school transmission. Because many positive contacts were asymptomatic, contact tracing should be paired with testing, regardless of symptoms.


Subject(s)
COVID-19 , SARS-CoV-2 , Contact Tracing , Georgia/epidemiology , Humans , Schools , Students
5.
BMC Public Health ; 22(1): 101, 2022 01 14.
Article in English | MEDLINE | ID: mdl-35031000

ABSTRACT

BACKGROUND: There is a continuing risk for COVID-19 transmission in school settings while transmission is ongoing in the community, particularly among unvaccinated populations. To ensure that schools continue to operate safely and to inform implementation of prevention strategies, it is imperative to gain better understanding of the risk behaviors of staff and students. This secondary analysis describes the prevalence of COVID-19 risk behaviors in an exposed population of students and school staff in the pre-vaccine era and identifies associations between these behaviors and testing positive for SARS-CoV-2. METHODS: From December 2020-January 2021, school staff and students exposed to confirmed COVID-19 cases in a Georgia school district were tested for SARS-CoV-2 and surveyed regarding risk behaviors in and out of school. Prevalence of risk behaviors was described by age group and school level, and associations with SARS-CoV-2 positivity were identified using chi squared tests. RESULTS: Overall, 717 students and 79 school staff participated in the investigation; SARS-CoV-2 positivity was 9.2%. In the 2 weeks prior to COVID-19 exposure, 24% of participants reported unmasked indoor time at school, 40% attended social gatherings with non-household members, and 71% visited out-of-school indoor locations, including 19% who ate indoors in restaurants. Frequencies of risk behaviors increased by age. Among students, 17% participated in school sports, of whom 86% participated without a mask. SARS-CoV-2 positivity was significantly associated with school sports and unmasked time in sports. Among K-5 students, positivity was associated with exposure to a teacher index case. CONCLUSIONS: This analysis highlights the high prevalence of risk behaviors in an unvaccinated population exposed to COVID-19 in school and identifies an association between student sports participation and SARS-CoV-2 positivity. These findings illustrate the importance of school-level prevention measures to reduce SARS-CoV-2 transmission, including limiting close-contact indoor sports and promoting consistent mask use in unvaccinated individuals. Future research could explore the role of community vaccination programs as a strategy to reduce COVID-19 transmission and introductions into school settings.


Subject(s)
COVID-19 , Vaccines , Georgia , Humans , Prevalence , Risk-Taking , SARS-CoV-2 , Schools
6.
MMWR Morb Mortal Wkly Rep ; 70(8): 289-292, 2021 02 26.
Article in English | MEDLINE | ID: mdl-33630823

ABSTRACT

In-person learning benefits children and communities (1). Understanding the context in which transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), occurs in schools is critical to improving the safety of in-person learning. During December 1, 2020-January 22, 2021, Cobb and Douglas Public Health (CDPH), the Georgia Department of Public Health (GDPH), and CDC investigated SARS-CoV-2 transmission in eight public elementary schools in a single school district. COVID-19 cases* among educators and students were either self-reported or identified by local public health officials. Close contacts (contacts)† of persons with a COVID-19 case received testing. Among contacts who received positive test results, public health investigators assessed epidemiologic links, probable transmission directionality, and the likelihood of in-school transmission.§ Nine clusters of three or more epidemiologically linked COVID-19 cases were identified involving 13 educators and 32 students at six of the eight elementary schools. Two clusters involved probable educator-to-educator transmission that was followed by educator-to-student transmission and resulted in approximately one half (15 of 31) of school-associated cases. Sixty-nine household members of persons with school-associated cases were tested, and 18 (26%) received positive results. All nine transmission clusters involved less than ideal physical distancing, and five involved inadequate mask use by students. Educators were central to in-school transmission networks. Multifaceted mitigation measures in schools, including promotion of COVID-19 precautions outside of school, minimizing in-person adult interactions at school, and ensuring universal and correct mask use and physical distancing among educators and students when in-person interaction is unavoidable, are important in preventing in-school transmission of SARS-CoV-2. Although not required for reopening schools, COVID-19 vaccination should be considered as an additional mitigation measure to be added when available.


Subject(s)
COVID-19/epidemiology , COVID-19/transmission , School Teachers/statistics & numerical data , Students/statistics & numerical data , COVID-19/prevention & control , Cluster Analysis , Georgia/epidemiology , Humans , Schools
7.
J Sch Nurs ; 37(6): 503-512, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34612108

ABSTRACT

This study's goal was to characterize the utility of symptom screening in staff and students for COVID-19 identification and control of transmission in a school setting. We conducted a secondary analysis of cross-sectional data for staff, students and associated household members in a Georgia school district exposed to COVID-19 cases who received RT-PCR testing and symptom monitoring. Among positive contacts, 30/49 (61%) of students and 1/6 (17%) of staff reported no symptoms consistent with COVID-19. Symptom sensitivity was 30% in elementary students and 42% in middle/high students. Fifty-three percent (10/19) of symptomatic positive contacts had at least one household member test positive for SARS-CoV-2 compared with 50% (10/20) of asymptomatic positive contacts. The absence of symptoms in children is not indicative of a lack of SARS-CoV-2 infection or reduced risk of infection for associated household members. Testing all close contacts of people with COVID-19 in schools is needed to interrupt transmission networks.


Subject(s)
COVID-19 , Child , Cross-Sectional Studies , Georgia/epidemiology , Humans , SARS-CoV-2 , Schools
8.
J Org Chem ; 85(19): 12108-12116, 2020 10 02.
Article in English | MEDLINE | ID: mdl-32829632

ABSTRACT

An effective design strategy with an efficient synthetic route to xanthene-based far-red to near-infrared dyes is reported. The dyes were prepared by the Suzuki cross-coupling of the electron-poor fluorescein ditriflate with the electron-rich boronic acid/ester-functionalized pyrrole (2C/3C) and indole (2D/3D) moieties. Upon treatment with trifluoroacetic acid, the closed nonfluorescent forms of the dyes (2C and 2D) ring-opened to their fluorescent forms (3C and 3D). The absorption maxima were 665 and 704 nm, while the emission maxima were 717 and 719 nm for 3C and 3D, respectively. The closed forms of the dyes were soluble in chloroform and acetonitrile. To test the efficacy of the dyes as probes, a turn-off fluoride ion probe was prepared from 3C, which consisted of a silyl ester receptor. The probe responded strongly to low concentrations of fluoride, carbonate, and acetate ions, weakly to phosphate ions, but not to the other halogens. Moreover, the probe can detect the minimum concentration of F- in water.

9.
Emerg Infect Dis ; 25(10): 1834-1842, 2019 10.
Article in English | MEDLINE | ID: mdl-31538559

ABSTRACT

In 2017, a total of 8,819 cases of diphtheria were reported worldwide, the most since 2004. However, recent diphtheria epidemiology has not been well described. We analyzed incidence data and data from the literature to describe diphtheria epidemiology. World Health Organization surveillance data were 81% complete; completeness varied by region, indicating underreporting. As national diphtheria-tetanus-pertussis (DTP) 3 coverage increased, the proportion of case-patients <15 years of age decreased, indicating increased protection of young children. In countries with higher case counts, 66% of case-patients were unvaccinated and 63% were <15 years of age. In countries with sporadic cases, 32% of case-patients were unvaccinated and 66% were >15 years of age, consistent with waning vaccine immunity. Global DTP3 coverage is suboptimal. Attaining high DTP3 coverage and implementing recommended booster doses are necessary to decrease diphtheria incidence. Collection and use of data on subnational and booster dose coverage, enhanced laboratory capacity, and case-based surveillance would improve data quality.


Subject(s)
Diphtheria/epidemiology , Global Health/statistics & numerical data , Adolescent , Child , Child, Preschool , Diphtheria/prevention & control , Diphtheria-Tetanus-Pertussis Vaccine/therapeutic use , Humans , Incidence , Infant , Population Surveillance , Vaccination Coverage/statistics & numerical data
10.
J Org Chem ; 84(20): 13186-13193, 2019 10 18.
Article in English | MEDLINE | ID: mdl-31479270

ABSTRACT

A NIR II emissive dye was synthesized by the C-H bond functionalization of 1-methyl-2-phenylindolizine with 3,6-dibromoxanthene. The rhodindolizine (RhIndz) spirolactone product was nonfluorescent; however, upon opening of the lactone ring by the formation of the ethyl ester derivative, the fluorophore absorbs at 920 nm and emits at 1092 nm, which are both in the NIR II region. In addition, 4-cyanophenyl- (CNRhIndz) and 4-methoxyphenyl-substituted rhodindolizine (MeORhIndz) could also be prepared by the C-H activation reaction.

11.
Emerg Infect Dis ; 23(3): 456-462, 2017 03.
Article in English | MEDLINE | ID: mdl-28221125

ABSTRACT

Current US guidelines recommend longer treatment for tuberculosis (TB) caused by pyrazinamide-resistant organisms (e.g., Mycobacterium bovis) than for M. tuberculosis TB. We compared treatment response times for patients with M. bovis TB and M. tuberculosis TB reported in the United States during 2006-2013. We included culture-positive, pulmonary TB patients with genotyping results who received standard 4-drug treatment at the time of diagnosis. Time to sputum-culture conversion was defined as time between treatment start date and date of first consistently culture-negative sputum. We analyzed 297 case-patients with M. bovis TB and 30,848 case-patients with M. tuberculosis TB. After 2 months of treatment, 71% of M. bovis and 65% of M. tuberculosis TB patients showed conversion of sputum cultures to negative. Likelihood of culture conversion was higher for M. bovis than for M. tuberculosis, even after controlling for treatment administration type, sex, and a composite indicator of bacillary burden.


Subject(s)
Antitubercular Agents/therapeutic use , Mycobacterium bovis/isolation & purification , Mycobacterium tuberculosis/isolation & purification , Sputum/microbiology , Tuberculosis, Pulmonary/microbiology , Adolescent , Adult , Aged , Child , Child, Preschool , Drug Therapy, Combination , Female , Genotype , Humans , Infant , Male , Middle Aged , Tuberculosis, Pulmonary/drug therapy , Tuberculosis, Pulmonary/epidemiology , United States , Young Adult
12.
MMWR Morb Mortal Wkly Rep ; 66(44): 1226-1229, 2017 Nov 10.
Article in English | MEDLINE | ID: mdl-29121004

ABSTRACT

The collection, analysis, and use of data to measure and improve immunization program performance are priorities for the World Health Organization (WHO), global partners, and national immunization programs (NIPs). High quality data are essential for evidence-based decision-making to support successful NIPs. Consistent recording and reporting practices, optimal access to and use of health information systems, and rigorous interpretation and use of data for decision-making are characteristics of high-quality immunization information systems. In 2015 and 2016, immunization information system assessments (IISAs) were conducted in Kenya and Ghana using a new WHO and CDC assessment methodology designed to identify root causes of immunization data quality problems and facilitate development of plans for improvement. Data quality challenges common to both countries included low confidence in facility-level target population data (Kenya = 50%, Ghana = 53%) and poor data concordance between child registers and facility tally sheets (Kenya = 0%, Ghana = 3%). In Kenya, systemic challenges included limited supportive supervision and lack of resources to access electronic reporting systems; in Ghana, challenges included a poorly defined subdistrict administrative level. Data quality improvement plans (DQIPs) based on assessment findings are being implemented in both countries. IISAs can help countries identify and address root causes of poor immunization data to provide a stronger evidence base for future investments in immunization programs.


Subject(s)
Health Information Systems/standards , Immunization Programs/organization & administration , Ghana , Humans , Kenya , Program Evaluation
13.
MMWR Morb Mortal Wkly Rep ; 66(12): 339-342, 2017 Mar 31.
Article in English | MEDLINE | ID: mdl-28358797

ABSTRACT

In 2012, Uganda introduced the use of GeneXpert MTB/RIF (Cepheid, Sunnyvale CA), a sensitive, automated, real-time polymerase chain reaction-based platform for tuberculosis (TB) diagnosis, for programmatic use among children, adults with presumptive human immunodeficiency virus (HIV)-associated TB, and symptomatic persons at risk for rifampicin (RIF)-resistant TB. The effect of using the platform's Xpert MTB/RIF assay on TB care and control was assessed using routinely collected programmatic data; in addition, a retrospective review of district quarterly summaries using abstracted TB register data from purposively selected facilities in the capital city of Kampala was conducted. Case notification rates were calculated and nonparametric statistical methods were used for analysis. No statistically significant differences were observed in case notification rates before and after the Xpert MTB/RIF assay became available, although four of 10 districts demonstrated a statistically significant difference in bacteriologically confirmed TB. Once the GeneXpert MTB/RIF platform is established and refined, a more comprehensive evaluation should be conducted.


Subject(s)
Automation, Laboratory , Molecular Diagnostic Techniques/methods , Mycobacterium tuberculosis/isolation & purification , Population Surveillance/methods , Tuberculosis/diagnosis , Adult , Child , Drug Resistance, Multiple , HIV Infections/epidemiology , Humans , Mycobacterium tuberculosis/drug effects , Retrospective Studies , Tuberculosis/epidemiology , Uganda/epidemiology
14.
Clin Infect Dis ; 63(5): 594-601, 2016 Sep 01.
Article in English | MEDLINE | ID: mdl-27298329

ABSTRACT

BACKGROUND: Using genotyping techniques that have differentiated Mycobacterium bovis from Mycobacterium tuberculosis since 2005, we review the epidemiology of human tuberculosis caused by M. bovis in the United States and validate previous findings nationally. METHODS: All tuberculosis cases with a genotyped M. tuberculosis complex isolate reported during 2006-2013 in the United States were eligible for analysis. We used binomial regression to identify characteristics independently associated with M. bovis disease using adjusted prevalence ratios (aPRs) and corresponding 95% confidence intervals (CIs). RESULTS: During 2006-2013, the annual percentages of tuberculosis cases attributable to M. bovis remained consistent nationally (range, 1.3%-1.6%) among all tuberculosis cases (N = 59 273). Compared with adults 25-44 years of age, infants aged 0-4 years (aPR, 1.9 [95% CI, 1.4-2.8]) and children aged 5-14 years (aPR, 4.0 [95% CI, 3.1-5.3]) had higher prevalences of M. bovis disease. Patients who were foreign-born (aPR, 1.4 [95% CI, 1.2-1.7]), Hispanic (aPR, 3.9 [95% CI, 3.0-5.0]), female (aPR, 1.4 [95% CI, 1.3-1.6]), and resided in US-Mexico border counties (aPR, 2.0 [95% CI, 1.7-2.4]) also had higher M. bovis prevalences. Exclusively extrapulmonary disease (aPR, 3.7 [95% CI, 3.3-4.2]) or disease that was both pulmonary and extrapulmonary (aPR, 2.4 [95% CI, 2.1-2.9]) were associated with a higher prevalence of M. bovis disease. CONCLUSIONS: Children, foreign-born persons, Hispanics, and females are disproportionately affected by M. bovis, which was independently associated with extrapulmonary disease. Targeted prevention efforts aimed at Hispanic mothers and caregivers are warranted.


Subject(s)
Mycobacterium bovis , Tuberculosis/epidemiology , Tuberculosis/microbiology , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Multivariate Analysis , Prevalence , Risk Factors , United States/epidemiology , Young Adult
15.
MMWR Morb Mortal Wkly Rep ; 64(10): 265-9, 2015 Mar 20.
Article in English | MEDLINE | ID: mdl-25789741

ABSTRACT

In 2014, a total of 9,412 new tuberculosis (TB) cases were reported in the United States, with an incidence rate of 3.0* cases per 100,000 persons, a decrease of 2.2% from 2013. Although overall numbers of TB cases and rates continue to decline, the percentage decrease in rate is the smallest decrease in over a decade (1). This report summarizes provisional TB surveillance data reported to CDC's National Tuberculosis Surveillance System for 2014. TB cases and rates decreased among U.S.-born persons, and although the case rate also decreased among foreign-born persons, there was an increase in total number of cases among foreign-born persons. The rate among foreign-born persons in the United States in 2014 was 13.4 times higher than among U.S.-born persons. Racial/ethnic minorities continue to be disproportionately affected by TB within the United States. Asians continue to be the racial/ethnic group with the largest number of TB cases. Compared with non-Hispanic whites, the TB rate among Asians was 28.5 times higher, whereas rates among non-Hispanic blacks and Hispanics were each eight times higher. Four states (California, Texas, New York, and Florida), representing approximately one third of the U.S. population, accounted for half of all TB cases reported in 2014. Continued progress toward TB elimination in the United States will require focused TB control efforts among populations and in geographic areas with disproportionate burdens of TB.


Subject(s)
Population Surveillance , Tuberculosis/epidemiology , Black or African American/statistics & numerical data , Asian/statistics & numerical data , Hispanic or Latino/statistics & numerical data , Humans , Incidence , Tuberculosis/ethnology , United States/epidemiology , White People/statistics & numerical data
16.
MMWR Morb Mortal Wkly Rep ; 64(7): 188-92, 2015 Feb 27.
Article in English | MEDLINE | ID: mdl-25719682

ABSTRACT

West Africa is experiencing its first epidemic of Ebola virus disease (Ebola). As of February 9, Liberia has reported 8,864 Ebola cases, of which 3,147 were laboratory-confirmed. Beginning in August 2014, the Liberia Ministry of Health and Social Welfare (MOHSW), supported by CDC, the World Health Organization (WHO), and others, began systematically investigating and responding to Ebola outbreaks in remote areas. Because many of these areas lacked mobile telephone service, easy road access, and basic infrastructure, flexible and targeted interventions often were required. Development of a national strategy for the Rapid Isolation and Treatment of Ebola (RITE) began in early October. The strategy focuses on enhancing capacity of county health teams (CHT) to investigate outbreaks in remote areas and lead tailored responses through effective and efficient coordination of technical and operational assistance from the MOHSW central level and international partners. To measure improvements in response indicators and outcomes over time, data from investigations of 12 of 15 outbreaks in remote areas with illness onset dates of index cases during July 16-November 20, 2014, were analyzed. The times to initial outbreak alerts and durations of the outbreaks declined over that period while the proportions of patients who were isolated and treated increased. At the same time, the case-fatality rate in each outbreak declined. Implementation of strategies, such as RITE, to rapidly respond to rural outbreaks of Ebola through coordinated and tailored responses can successfully reduce transmission and improve outcomes.


Subject(s)
Disease Outbreaks/prevention & control , Ebolavirus/isolation & purification , Hemorrhagic Fever, Ebola/prevention & control , Rural Population , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Disease Outbreaks/statistics & numerical data , Female , Hemorrhagic Fever, Ebola/epidemiology , Humans , Infant , Liberia/epidemiology , Male , Middle Aged , Rural Population/statistics & numerical data , Time Factors , Young Adult
17.
J Fluoresc ; 25(2): 231-7, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25686771

ABSTRACT

A series of fluorescent pH probes based on the spiro-cyclic rhodamine core, aminomethylrhodamines (AMR), was synthesized and the effect of cycloalkane ring size on the acid/base properties of the AMR system was explored. The study involved a series of rhodamine 6G (cAMR6G) and rhodamine B (cAMR) pH probes with cycloalkane ring sizes from C-3 to C-6 on the spiro-cyclic amino group. It is known that the pKa value of cycloalkylamines can be tuned by different ring sizes in accordance with the Baeyer ring strain theory. Smaller ring amines have lower pKa value, i.e., they are less basic, such that the relative order in cycloalkylamine basicity is: cyclohexyl > cyclopentyl > cyclobutyl > cyclopropyl. Herein, it was found that the pKa values of the cAMR and cAMR6G systems can also be predicted by Baeyer ring strain theory. The pKa values for the cAMR6G series were shown to be higher than the cAMR series by a value of approximately 1.


Subject(s)
Cycloparaffins/chemistry , Rhodamines/chemistry , Hydrogen-Ion Concentration
18.
Polymer (Guildf) ; 55(16): 3551-3556, 2014 Aug 05.
Article in English | MEDLINE | ID: mdl-25253913

ABSTRACT

Random cationic copolymer brushes composed of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and N-isopropylacrylamide (NIPAAm) were synthesized using the atom transfer radical polymerization (ATRP) method. The effects of varying the monomer feed ratios (30:70 and 70:30 DMAEMA:NIPAAm) and polymerization times on the film height, morphology and stimuli response to pH of the brush were evaluated. While the polymerization time was found to have little influence on the properties of the brushes, the monomer feed ratios had a great impact. The 70 % DMAEMA polymer brush had similar height as the 30 % DMAEMA brush after 45 min; however, it had a greater response to pH and morphological change compared to the 30 % DMAEMA. The 70 % DMAEMA brush was used to demonstrate an efficient approach to alleviate the ion suppression effect in MALDI analysis of complex mixtures by effectively fractionating a binary mixture of peptides prior to MALDI-MS analysis.

19.
J Am Chem Soc ; 135(36): 13365-70, 2013 Sep 11.
Article in English | MEDLINE | ID: mdl-23889259

ABSTRACT

We report the synthesis and characterization of a fluorescent probe (Hypo-SiF) designed for the detection of hypochlorous acid (HOCl) using a silicon analogue of fluorescein (SiF). The probe is regulated in an "off-on" fashion by a highly selective thioether spirocyclic nonfluorescent structure that opens to form a mixture of fluorescent products in the presence of HOCl. Over a range of pH values, the probe reacts with a stoichiometric amount of HOCl, resulting in a mixture of two pH-dependent fluorescent species, a SiF disulfide product and a SiF sulfonate product. The unique colorimetric properties of the individual SiF fluorophores were utilized to perform simultaneous detection of HOCl and pH. When an excess of HOCl is present, the SiF fluorophores become chlorinated, via an intermediate halohydrin, resulting in a more pH independent and red-shifted fluorophore.


Subject(s)
Fluorescein/chemistry , Fluorescent Dyes/chemistry , Hypochlorous Acid/chemistry , Silicon/chemistry , Fluorescent Dyes/chemical synthesis , Hydrogen-Ion Concentration , Molecular Structure
20.
Langmuir ; 29(2): 696-700, 2013 Jan 15.
Article in English | MEDLINE | ID: mdl-23244629

ABSTRACT

A cationic polymer nanobrush was synthesized, attached to a MALDI target, and used for the fractionation of peptides and proteins based on their pI, prior to analysis by MALDI-MS. The cationic polymer nanobrush was synthesized on a gold substrate by AIBN photoinitiated polymerization, using a 70:30 ratio of 2-aminoethyl methacrylate hydrochloride (AEMA):N-isopropylacrylamide (NIPAAM). This brush showed selectivity for adsorption of acidic peptides and proteins and allowed fractionation of simple two-component mixtures to be completed in less than 10 min. The brush-adsorbed biomolecules were recovered by treating the nanobrush with ammonium hydroxide, which effectively collapsed the brush, thereby releasing the trapped compounds for MALDI MS analysis. These results demonstrate that nanobrush can serve as a convenient platform for rapid fractionation of biomolecules prior to analysis by MALDI-MS.


Subject(s)
Acrylamides/chemistry , Chemical Fractionation/methods , Ethylamines/chemistry , Methacrylates/chemistry , Nanostructures/chemistry , Acids/chemistry , Adsorption , Ammonium Hydroxide , Bradykinin/analysis , Hydroxides/chemistry , Insulin/analysis , Muramidase/analysis , Polymerization , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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