Elemental Fluorine Detection by Dielectric Barrier Discharge Coupled to Nanoelectrospray Ionization Mass Spectrometry for Nontargeted Analysis of Fluorinated Compounds.

The growing use of fluorochemicals has elevated the need for nontargeted detection of unknown fluorinated compounds and transformation products. Elemental mass spectrometry (MS) coupled to chromatography offers a facile approach for such analyses by using fluorine as an elemental tag. However, efficient ionization of fluorine has been an ongoing challenge. Here, we demonstrate a novel atmospheric-pressure elemental ionization method where fluorinated compounds separated by gas chromatography (GC) are converted to Na2F+ for nontargeted detection. The compounds are first introduced into a helium dielectric barrier discharge (DBD) for breakdown. The plasma products are subsequently ionized by interaction with a nanoelectrospray ionization (nano-ESI) plume of sodium-containing aqueous electrolytes. Our studies point to HF as the main plasma product contributing to Na2F+ formation. Moreover, the results reveal that Na2F+ is largely formed by the ion-neutral reaction between HF and Na2A(NaA)n+, gas-phase reagent ions produced by nano-ESI where A represents the anion of the electrolyte. Near-uniform fluorine response factors are obtained for a wide range of compounds, highlighting good efficiency of HF formation by DBD regardless of the chemical structure of the compounds. Detection limits of 3.5-19.4 pg of fluorine on-column are obtained using the reported GC-DBD-nano-ESI-MS. As an example of nontargeted screening, extractions from oil-and-water-repellent fabrics are analyzed via monitoring Na2F+, resulting in detection of a fluorinated compound on a clothing item. Notably, facile switching of the ion source to atmospheric-pressure chemical ionization with the exact same chromatographic method allows identification of the detected compound at the flagged retention time.

Classifying single fibers based on fluorinated surface treatments.

Fibers are an important form of forensic evidence, but their evidential value can be severely limited when the identified characteristics of the fibers are common, such as blue cotton. Detecting chemical fiber treatments offers an avenue to further classify fibers and to improve their evidential value. In this report, we investigate the potential of fluoropolymer fiber coatings, used to impart oil and water-repellent properties in fabrics, for differentiating between fibers. The thin nature of these fiber surface modifications creates an analytical challenge for their detection on a single fiber, a typical sample size for forensic evidence. Specifically, pyrolysis-gas chromatography-mass spectrometry (py-GC-MS) has shown promising selectivity but the sensitivity of the method is not adequate for single-fiber analysis of fluorinated coatings. To overcome this challenge, we utilize a newly developed elemental ionization source, plasma-assisted reaction chemical ionization (PARCI). The high sensitivity of py-GC-PARCI-MS for elemental fluorine analysis offers selective and sensitive detection of fluorinated pyrolysates among the non-fluorinated pyrolysates of the fiber core. As a result, fluoropolymer coatings are detected from 10-mm single-fiber samples. The technique is applied for classification of 22 fiber types, resulting in 4 distinct groups via hierarchical cluster analysis based on similarity of fluorine pyrograms. These results present the first study to classify fibers based on fluorinated coatings, and highlight the potential of py-GC-PARCI-MS for forensic analyses. Graphical Abstract ᅟ.

Atmospheric-Pressure Dielectric Barrier Discharge as an Elemental Ion Source for Gas Chromatographic Analysis of Organochlorines.

Atmospheric-pressure dielectric barrier discharge (AP-DBD) plasma has emerged in recent years as a versatile plasma for molecular ionization and elemental spectroscopy. However, its capabilities as an elemental ion source have been less explored, partly because of difficulties in the detection of positive elemental ions from this low-gas-temperature plasma. In this work, we investigate the detection of negative elemental ions to enable elemental mass spectrometry (MS) using AP-DBD. A gas chromatograph is coupled to a helium AP-DBD apparatus and positioned in front of an atmospheric-pressure-sampling mass spectrometer with no modifications to the ion sampling interface. We demonstrate that Cl- ions are detected with a compound-independent efficiency, enabling elemental quantification of organochlorines. Further, addition of oxygen at low concentration (11 ppm, v/v) to the helium plasma improves the analytical performance by reducing postcolumn peak broadening, whereas high oxygen concentrations (>110 ppm, v/v) lead to loss of the compound-independent response. The optimized GC-AP-DBD-MS setup shows close to 2 orders of magnitude of linearity for its compound-independent Cl response and offers detection limits of 0.5-1 pg of Cl on column (0.6 pg/s), suitable for analysis of organochlorines in food samples. We demonstrate this capability by analyzing orange juice spiked with pesticides at 9 µg/L and a single internal standard. Importantly, we demonstrate that a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction followed by GC-AP-DBD-MS quantification using the single standard provides acceptable recoveries (80-120%). These results highlight uniform QuEChERS extraction of a range of compounds and the compound-independent response of AP-DBD for Cl, making the combination of the two methods desirable for the rapid quantification of organochlorines. Furthermore, we discuss ionization matrix effects in AP-DBD for chlorine detection and offer strategies to flag matrix-impacted analytes. These results suggest that AP-DBD has the potential to become a unified ion source for both elemental quantification and molecular identification of GC eluents on a single MS platform.

Diabetes Mellitus-Not Just Type 1 or Type 2 Anymore.

INTRODUCTION: Diabetes mellitus traditionally has been categorized as type 1 (insulin deficiency due to autoimmune destruction of islet cells) or type 2 (insulin resistance with the development of relative insulin deficiency). However, other pathophysiologic etiologies for diabetes must be considered in the evaluation of patients with new-onset diabetes. CASE PRESENTATION: We report the case of a 50-year-old man with a diagnosis of type 2 diabetes mellitus who-despite appropriate pharmacotherapy-developed worsening hyperglycemia. Further investigation revealed the presence of metastatic pancreatic cancer. DISCUSSION: Although an association between pancreatic cancer and diabetes has been noted widely in the gastroenterology, oncology, and endocrine literature, a paucity of primary care literature on the topic exists. Features of predominant insulin deficiency and new onset of diabetes in a patient without family history of type 2 diabetes should raise suspicion for undetected/early-stage pancreatic cancer. CONCLUSIONS: This case highlights the importance of considering all possible pathophysiologic etiologies when a patient has a new diagnosis of diabetes. Clinicians should consider the possibility of pancreatic cancer in patients with new-onset diabetes mellitus, especially when features not characteristic of type 2 diabetes are present. Understanding the relationship between diabetes and pancreatic cancer has the potential to improve early detection of pancreatic cancer and can provide an opportunity for early treatment and improved survival.

Atrioesophageal Fistula: A Rare Complication of Radiofrequency Ablation.

75-year-old woman was admitted with fever, chills, altered mentation, and right-sided weakness. A month earlier, she had undergone catheter radiofrequency ablation for treatment of chronic atrial fibrillation. A magnetic resonance imaging scan of her brain revealed septic emboli with multiple bilateral cerebral and cerebellar infarcts, as well as extensive bilateral leptomeningeal enhancement. Blood cultures were positive for Streptococcus mitis, Rothia mucilaginosa, Streptococcus pneumonia, and Candida albicans, which suggested a connection between gastrointestinal and cardiovascular systems. A chest computed tomography scan with contrast showed a curvilinear low attenuation structure communicating between the esophagus and the left pulmonary vein-an atrioesophageal fistula. Ten days after admission, the patient died from multiple cerebral septic emboli secondary to atrioesophageal fistula following radiofrequency ablation.

Gene-environment interplay in Drosophila melanogaster: chronic food deprivation in early life affects adult exploratory and fitness traits.

Early life adversity has known impacts on adult health and behavior, yet little is known about the gene-environment interactions (GEIs) that underlie these consequences. We used the fruit fly Drosophila melanogaster to show that chronic early nutritional adversity interacts with rover and sitter allelic variants of foraging (for) to affect adult exploratory behavior, a phenotype that is critical for foraging, and reproductive fitness. Chronic nutritional adversity during adulthood did not affect rover or sitter adult exploratory behavior; however, early nutritional adversity in the larval period increased sitter but not rover adult exploratory behavior. Increasing for gene expression in the mushroom bodies, an important center of integration in the fly brain, changed the amount of exploratory behavior exhibited by sitter adults when they did not experience early nutritional adversity but had no effect in sitters that experienced early nutritional adversity. Manipulation of the larval nutritional environment also affected adult reproductive output of sitters but not rovers, indicating GEIs on fitness itself. The natural for variants are an excellent model to examine how GEIs underlie the biological embedding of early experience.

Bacterial hand contamination and transfer after use of contaminated bulk-soap-refillable dispensers.

Bulk-soap-refillable dispensers are prone to extrinsic bacterial contamination, and recent studies demonstrated that approximately one in four dispensers in public restrooms are contaminated. The purpose of this study was to quantify bacterial hand contamination and transfer after use of contaminated soap under controlled laboratory and in-use conditions in a community setting. Under laboratory conditions using liquid soap experimentally contaminated with 7.51 log(10) CFU/ml of Serratia marcescens, an average of 5.28 log(10) CFU remained on each hand after washing, and 2.23 log(10) CFU was transferred to an agar surface. In an elementary-school-based field study, Gram-negative bacteria on the hands of students and staff increased by 1.42 log(10) CFU per hand (26-fold) after washing with soap from contaminated bulk-soap-refillable dispensers. In contrast, washing with soap from dispensers with sealed refills significantly reduced bacteria on hands by 0.30 log(10) CFU per hand (2-fold). Additionally, the mean number of Gram-negative bacteria transferred to surfaces after washing with soap from dispensers with sealed-soap refills (0.06 log(10) CFU) was significantly lower than the mean number after washing with contaminated bulk-soap-refillable dispensers (0.74 log(10) CFU; P < 0.01). Finally, significantly higher levels of Gram-negative bacteria were recovered from students (2.82 log(10) CFU per hand) than were recovered from staff (2.22 log(10) CFU per hand) after washing with contaminated bulk soap (P < 0.01). These results demonstrate that washing with contaminated soap from bulk-soap-refillable dispensers can increase the number of opportunistic pathogens on the hands and may play a role in the transmission of bacteria in public settings.

Effects of outdoor weathering and laundering on the detection and classification of fluorinated oil-and-water-repellent fabric coatings.

Fluorinated polymer coatings are used to impart durable oil-and-water-repellent properties on fabrics, potentially offering a persistent fiber characteristic for forensic fiber comparisons. To evaluate the persistence of these coatings, we investigate effects of outdoor weathering and laundering on detection and classification of the fluorinated oil-and-water-repellent coatings on 9 garments and 2 spray-coated fabric samples. Single fibers from the samples are pyrolyzed and subjected to gas chromatography coupled to a fluorine-selective detector. The positive detection of coatings is indicated by a signal-to-noise ratio (S/N) >50 for the tallest peak in the pyrograms. Moreover, a multinomial logistic regression model trained using fibers prior to weathering and laundering is utilized to determine the class of the weathered and laundered fibers, providing a metric to evaluate the effect of these processes on fiber classification. Notably, fluorinated coatings are detected on all of the fibers exposed to outdoor elements in Arlington, VA, up to 12 weeks from August to October 2020, while a detection rate of 95.5% is achieved for samples laundered up to 10 wash cycles. The detection rate prior to weathering and laundering was 98%, indicating negligible effect of these processes on detection of coatings. The classification accuracy is determined to be 99% and 100% for weathered and laundered samples, respectively, illustrating that these processes do not significantly affect the major pyrolysis products of the coatings responsible for classification. These results highlight the persistence of the fluorinated oil-and-water-repellent fabric coatings and their potential for forensic fiber discrimination at single-fiber level.

Detection and diversity of fluorinated oil- and water-repellent coatings on apparel fibers.

Fluorinated coatings, often used for oil and water repellency and stain resistance in fabrics, are potentially persistent forensic fiber markers. However, they have received limited attention because of challenges in their detection caused by the small size of a single fiber and thin nature of stain-resistant coatings. Here, we utilize a sensitive fluorine-selective analytical technique to detect and evaluate diversity of fluorinated coatings in apparel. Twelve clothing items marketed as stain-resistant were tested with nine showing oil- and water-repellent properties. Fluorinated pyrolysis products of single fibers from all of the nine items were detected by gas chromatography coupled to plasma-assisted reaction chemical ionization mass spectrometry (GC-PARCI-MS), indicating the prevalence of fluoropolymer coatings in stain-resistant clothing articles. Furthermore, three major classes of fluorinated coatings were identified via principal component analysis of pyrogram patterns. The classes were coating-specific and did not correlate with fiber core and color, highlighting a robust detection methodology. To evaluate the effect of fiber lifting in crime scenes, fibers from the 9 clothing items were used to develop a multinomial logistic regression model based on pyrogram principal components. The model was then tested using fibers subjected to contact with Post-it® notes. The test set fibers were sampled from the clothing items of the training set and from three additional garments of differing color but the same brands as the training set. The coating classes were predicted with 98.4% accuracy, confirming robust classification of fiber coatings using py-GC-PARCI-MS regardless of fiber color, core, and fiber lifting.

An impact assessment and critical appraisal of the ISO standard for wheelchair vocabulary.

Wheelchairs are, for users, a primary means of mobility and an important means of performing activities of daily living. A common, accepted vocabulary is required to support and foster evidence-based practice and communication amongst professionals and with users. The international standard for wheelchair vocabulary, ISO 7176-26:2007, specifies terms and definitions with the purpose of eliminating confusion from the duplication or inappropriate use of terms. The aim of this study was to assess its impact and, based on that assessment, critically appraise the standard. Two databases were searched returning 189 and 283 unique articles with wheelchair in the title published between 2004-2006 and 2009-2011 respectively. Compliance, based on title and abstract usage, was poor, ranging from 0 to 50% correct usage, with no significant difference between pre- and post-publication. A review of prescription forms found only 9% correct usage. A survey of NHS wheelchair managers found that only 30% were positive that they had a copy despite 67% agreeing that the standard is important. The ISO wheelchair vocabulary standard was found not to be achieving its stated purpose. It is recommended that it be revised taking into account the findings of this study including the need for targeted dissemination and increased awareness.

CHD5 is required for neurogenesis and has a dual role in facilitating gene expression and polycomb gene repression.

The chromatin remodeler CHD5 is expressed in neural tissue and is frequently deleted in aggressive neuroblastoma. Very little is known about the function of CHD5 in the nervous system or its mechanism of action. Here we report that depletion of Chd5 in the developing neocortex blocks neuronal differentiation and leads to an accumulation of undifferentiated progenitors. CHD5 binds a large cohort of genes and is required for facilitating the activation of neuronal genes. It also binds a cohort of Polycomb targets and is required for the maintenance of H3K27me3 on these genes. Interestingly, the chromodomains of CHD5 directly bind H3K27me3 and are required for neuronal differentiation. In the absence of CHD5, a subgroup of Polycomb-repressed genes becomes aberrantly expressed. These findings provide insights into the regulatory role of CHD5 during neurogenesis and suggest how inactivation of this candidate tumor suppressor might contribute to neuroblastoma.

SaniTwice: a novel approach to hand hygiene for reducing bacterial contamination on hands when soap and water are unavailable.

The risk of inadequate hand hygiene in food handling settings is exacerbated when water is limited or unavailable, thereby making washing with soap and water difficult. The SaniTwice method involves application of excess alcohol-based hand sanitizer (ABHS), hand "washing" for 15 s, and thorough cleaning with paper towels while hands are still wet, followed by a standard application of ABHS. This study investigated the effectiveness of the SaniTwice methodology as an alternative to hand washing for cleaning and removal of microorganisms. On hands moderately soiled with beef broth containing Escherichia coli (ATCC 11229), washing with a nonantimicrobial hand washing product achieved a 2.86 (±0.64)-log reduction in microbial contamination compared with the baseline, whereas the SaniTwice method with 62 % ethanol (EtOH) gel, 62 % EtOH foam, and 70 % EtOH advanced formula gel achieved reductions of 2.64 ± 0.89, 3.64 ± 0.57, and 4.61 ± 0.33 log units, respectively. When hands were heavily soiled from handling raw hamburger containing E. coli, washing with nonantimicrobial hand washing product and antimicrobial hand washing product achieved reductions of 2.65 ± 0.33 and 2.69 ± 0.32 log units, respectively, whereas SaniTwice with 62 % EtOH foam, 70 % EtOH gel, and 70 % EtOH advanced formula gel achieved reductions of 2.87 ± 0.42, 2.99 ± 0.51, and 3.92 ± 0.65 log units, respectively. These results clearly demonstrate that the in vivo antibacterial efficacy of the SaniTwice regimen with various ABHS is equivalent to or exceeds that of the standard hand washing approach as specified in the U.S. Food and Drug Administration Food Code. Implementation of the SaniTwice regimen in food handling settings with limited water availability should significantly reduce the risk of foodborne infections resulting from inadequate hand hygiene.

Evaluation of an electronic device for real-time measurement of alcohol-based hand rub use.

BACKGROUND: Observational surveys of hand hygiene compliance are time consuming. Measuring the use of a hand hygiene product is a less time-consuming method of monitoring the frequency of hand hygiene performance. OBJECTIVE: To evaluate the usefulness of electronic devices for monitoring alcohol-based hand rub use. DESIGN: Prospective observational trial. SETTING: A university-affiliated teaching hospital. METHODS: Prototypes of an electronic device designed to record each time a dispenser is used (hereafter referred to as a hand hygiene event) were placed in alcohol-based hand rub dispensers on the general medical ward and in the surgical intensive care unit. Data were downloaded wirelessly to a data logger and then uploaded to a dedicated Web site for analysis. Alcohol-based hand rub dispensers were located in patient rooms and in corridors. RESULTS: During a 6-month trial, 105,462 hand hygiene events occurred in the surgical intensive care unit, and 44,845 events occurred on the general medical ward. The dispensers located in patient rooms accounted for 47% of the hand hygiene events performed in the surgical intensive care unit but for only 36% of events on the general medical ward (P < .001). The dispensers most often used were located in corridors. Hand hygiene events were most common on Tuesdays, Wednesdays, and Thursdays, between 7:00 am and 11:00 am. CONCLUSIONS: The use of these electronic devices provided an efficient and accurate method of monitoring the frequency of alcohol-based hand rub performance on the general medical ward and in the surgical intensive care unit, and yielded more detailed information on usage patterns than did expressing use as liters per 1,000 patient-days. The wireless downloading of data from dispensers required a limited amount of time, and the dedicated Web site facilitated data analysis. Such devices should prove useful in monitoring the impact of various interventions on the frequency of hand hygiene performance.