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1.
Artigo em Francês | MEDLINE | ID: mdl-39060149

RESUMO

The MASK lift or subperiosteal lift of the upper and middle thirds of the face is a procedure that can be performed alone for aesthetic purposes, but can also be combined with reconstructive surgery of this region to improve the result. This procedure will enable the overall result to be enhanced in the management of complex pathologies. The aim of this article is to present the MASK lift surgical technique in detail, to explain its indications and to show that this surgical technique still has a place in our practice.

2.
Appl Microbiol Biotechnol ; 107(14): 4507-4518, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37272938

RESUMO

Formate is a promising energy carrier that could be used to transport renewable electricity. Some acetogenic bacteria, such as Eubacterium limosum, have the native ability to utilise formate as a sole substrate for growth, which has sparked interest in the biotechnology industry. However, formatotrophic metabolism in E. limosum is poorly understood, and a system-level characterisation in continuous cultures is yet to be reported. Here, we present the first steady-state dataset for E. limosum formatotrophic growth. At a defined dilution rate of 0.4 d-1, there was a high specific uptake rate of formate (280 ± 56 mmol/gDCW/d; gDCW = gramme dry cell weight); however, most carbon went to CO2 (150 ± 11 mmol/gDCW/d). Compared to methylotrophic growth, protein differential expression data and intracellular metabolomics revealed several key features of formate metabolism. Upregulation of phosphotransacetylase (Pta) appears to be a futile attempt of cells to produce acetate as the major product. Instead, a cellular energy limitation resulted in the accumulation of intracellular pyruvate and upregulation of pyruvate formate ligase (Pfl) to convert formate to pyruvate. Therefore, metabolism is controlled, at least partially, at the protein expression level, an unusual feature for an acetogen. We anticipate that formate could be an important one-carbon substrate for acetogens to produce chemicals rich in pyruvate, a metabolite generally in low abundance during syngas growth. KEY POINTS: First Eubacterium limosum steady-state formatotrophic growth omics dataset High formate specific uptake rate, however carbon dioxide was the major product Formate may be the cause of intracellular stress and biofilm formation.


Assuntos
Acetatos , Eubacterium , Acetatos/metabolismo , Eubacterium/genética , Eubacterium/metabolismo , Piruvatos/metabolismo , Formiatos/metabolismo
3.
J Eur Acad Dermatol Venereol ; 36 Suppl 6: 29-37, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35738811

RESUMO

Accumulating evidence from numerous comprehensive studies has demonstrated that blue light, in particular high-energy visible light, can exert a range of harmful effects on skin cells. These forms of radiation are now known to be able to trigger oxidation reactions, DNA damage, erythema and pigmentary changes, and may also be associated with photoaging. Sunscreens protecting the skin from only ultraviolet (UV)-B and UVA rays can therefore no longer be regarded as sufficient to help prevent skin damage from sunlight, and products containing filters that can provide broad-spectrum photoprotection are required. To meet this need, a new sunscreen formulation that provides photoprotection against solar radiation with wavelengths ranging from UV to visible light has been developed, using an innovative organic sun filter with unique optical properties: phenylene bis diphenyltriazine (TriAsorB™). This article outlines the development and characteristics of this innovative filter and describes new key results from studies performed to assess the effectiveness and safety of the filter and the new sunscreen product. The studies conducted so far demonstrate that the filter has a good human and environmental safety profile. In addition, the sunscreen, which contains TriAsorB in combination with three other UV filters to offer broad-spectrum sun protection with a high sun protection factor (SPF50+ ), appears to effectively prevent multiple forms of cellular photodamage, in particular blue light-induced oxidatively generated DNA lesions. Overall, the available data indicate that regular use of the TriAsorB-containing sunscreen could help prevent solar radiation-induced skin damage and the development of signs of premature skin aging, as well as photodermatoses caused or exacerbated by visible light.


Assuntos
Envelhecimento da Pele , Protetores Solares , Humanos , Pele , Fator de Proteção Solar , Luz Solar/efeitos adversos , Protetores Solares/farmacologia , Raios Ultravioleta/efeitos adversos
4.
Photochem Photobiol Sci ; 20(11): 1475-1486, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34643936

RESUMO

Sunlight induces actinic keratosis, skin cancers and photoaging. Photoprotection is thus a major issue in public health to prevent the harmful effects of solar ultraviolet (UV) radiations. Recent data have shown that the visible (VIS) and infrared (IR) radiations can lead to skin damage by oxidative stress, suggesting that a balanced protection across the entire spectrum of sunlight is necessary to prevent cutaneous alterations. In this context, we developed a new generation of sunfilter called Phenylene Bis-Diphenyltriazine or TriAsorB (CAS N°55514-22-2). The aim of the present study was to assess the photoprotective efficacy of TriAsorB from UV to IR light. Spectrophotometric assays were performed to measure absorption and reflectance of TriAsorB in the different spectral ranges of sunlight: UV, VIS including blue light or high energy visible (HEV) and IR. DNA damage was evaluated using reconstructed human epidermis (RHE): 8-hydroxy-2'-deoxyguanosine (8OHdG) in response to HEV exposure, pyrimidine dimers (CPDs) and (6-4) photoproducts following solar-simulated radiation (SSR). TriAsorB is a broad spectrum UVB + UVA filter including long UVA. Interestingly, it also absorbs VIS radiations, especially in the HEV region. These radiations are also reflected. Protection in the IR spectral range is weak. Furthermore, the sunfilter specifically protects the skin against the oxidative lesions 8OHdG induced by HEV and prevents SSR-induced DNA damage. Thus, TriAsorB is an innovative sunfilter that might be used in sun care products for skin photoprotection from UV to VIS radiations. Finally, it prevents sunlight genotoxicity and protected the skin against solar radiations, especially blue light.


Assuntos
Protetores Solares , Raios Ultravioleta , Humanos , Dímeros de Pirimidina , Pele , Luz Solar , Protetores Solares/farmacologia , Raios Ultravioleta/efeitos adversos
5.
J Appl Toxicol ; 39(2): 385-397, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30345528

RESUMO

Skin metabolism is important to consider when assessing local toxicity and/or penetration of chemicals and their metabolites. If human skin supply is limited, pig skin can be used as an alternative. To identify any species differences, we have investigated the metabolism of 10 chemicals in a pig and human skin explant model. Phase I metabolic pathways in skin from both species included those known to occur via cytochrome P450s, esterases, alcohol dehydrogenases and aldehyde dehydrogenases. Common Phase II pathways were glucuronidation and sulfation but other conjugation pathways were also identified. Chemicals not metabolized by pig skin (caffeine, IQ and 4-chloroaniline) were also not metabolized by human skin. Six chemicals metabolized by pig skin were metabolized to a similar extent (percentage parent remaining) by human skin. Human skin metabolites were also detected in pig skin incubations, except for one unidentified minor vanillin metabolite. Three cinnamyl alcohol metabolites were unique to pig skin but represented minor metabolites. There were notable species differences in the relative amounts of common metabolites. The difference in the abundance of the sulfate conjugates of resorcinol and 4-amino-3-nitrophenol was in accordance with the known lack of aryl sulfotransferase activity in pigs. In conclusion, while qualitative comparisons of metabolic profiles were consistent between pig and human skin, there were some quantitative differences in the percentage of metabolites formed. This preliminary assessment suggests that pig skin is metabolically competent and could be a useful tool for evaluating potential first-pass metabolism before testing in human-derived tissues.


Assuntos
Cosméticos/farmacocinética , Absorção Cutânea/efeitos dos fármacos , Pele/metabolismo , Administração Cutânea , Animais , Cosméticos/farmacologia , Sistema Enzimático do Citocromo P-450/metabolismo , Glucuronosiltransferase/metabolismo , Humanos , Desintoxicação Metabólica Fase I , Desintoxicação Metabólica Fase II , Técnicas de Cultura de Órgãos , Pele/efeitos dos fármacos , Pele/enzimologia , Especificidade da Espécie , Especificidade por Substrato , Sulfotransferases/metabolismo , Suínos , Distribuição Tecidual
6.
J Appl Toxicol ; 37(7): 806-816, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28139006

RESUMO

Partition (K) and diffusion (D) coefficients are important to measure for the modelling of skin penetration of chemicals through the stratum corneum (SC). We compared the feasibility of three protocols for the testing of 50 chemicals in our main studies, using three cosmetics-relevant model chemicals with a wide range of logP values. Protocol 1: SC concentration-depth profile using tape-stripping (measures KSC/v and DSC /HSC2 , where HSC is the SC thickness); Protocol 2A: incubation of isolated SC with chemical (direct measurement of KSC/v only) and Protocol 2B: diffusion through isolated SC mounted on a Franz cell (measures KSC/v and DSC /HSC2 , and is based on Fick's laws). KSC/v values for caffeine and resorcinol using Protocol 1 and 2B were within 30% of each other, values using Protocol 2A were ~two-fold higher, and all values were within 10-fold of each other. Only indirect determination of KSC/v by Protocol 2B was different from the direct measurement of KSC/v by Protocol 2A and Protocol 1 for 7-EC. The variability of KSC/v for all three chemicals using Protocol 2B was higher compared to Protocol 1 and 2A. DSC /HSC2 values for the three chemicals were of the same order of magnitude using all three protocols. Additionally, using Protocol 1, there was very little difference between parameters measured in pig and human SC. In conclusion, KSC/v, and DSC values were comparable using different methods. Pig skin might be a good surrogate for human skin for the three chemicals tested. Copyright © 2017 The Authors Journal of Applied Toxicology published by John Wiley & Sons Ltd.


Assuntos
Cosméticos/química , Cosméticos/metabolismo , Epiderme/metabolismo , Absorção Cutânea/efeitos dos fármacos , Adulto , Animais , Cafeína/metabolismo , Cumarínicos/metabolismo , Difusão/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Animais , Modelos Biológicos , Permeabilidade/efeitos dos fármacos , Resorcinóis/metabolismo , Suínos
7.
Anal Chem ; 87(7): 3812-9, 2015 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-25785933

RESUMO

Comprehensive two-dimensional (2D) gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) is a versatile instrumental platform capable of collecting highly informative, yet highly complex, chemical data for a variety of samples. Fisher-ratio (F-ratio) analysis applied to the supervised comparison of sample classes algorithmically reduces complex GC × GC-TOFMS data sets to find class distinguishing chemical features. F-ratio analysis, using a tile-based algorithm, significantly reduces the adverse effects of chromatographic misalignment and spurious covariance of the detected signal, enhancing the discovery of true positives while simultaneously reducing the likelihood of detecting false positives. Herein, we report a study using tile-based F-ratio analysis whereby four non-native analytes were spiked into diesel fuel at several concentrations ranging from 0 to 100 ppm. Spike level comparisons were performed in two regimes: comparing the spiked samples to the nonspiked fuel matrix and to each other at relative concentration factors of two. Redundant hits were algorithmically removed by refocusing the tiled results onto the original high resolution pixel level data. To objectively limit the tile-based F-ratio results to only features which are statistically likely to be true positives, we developed a combinatorial technique using null class comparisons, called null distribution analysis, by which we determined a statistically defensible F-ratio cutoff for the analysis of the hit list. After applying null distribution analysis, spiked analytes were reliably discovered at ∼1 to ∼10 ppm (∼5 to ∼50 pg using a 200:1 split), depending upon the degree of mass spectral selectivity and 2D chromatographic resolution, with minimal occurrence of false positives. To place the relevance of this work among other methods in this field, results are compared to those for pixel and peak table-based approaches.

8.
Anal Bioanal Chem ; 407(1): 321-30, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25315453

RESUMO

Recent efforts in predicting rocket propulsion (RP-1) fuel performance through modeling put greater emphasis on obtaining detailed and accurate fuel properties, as well as elucidating the relationships between fuel compositions and their properties. Herein, we study multidimensional chromatographic data obtained by comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC × GC-TOFMS) to analyze RP-1 fuels. For GC × GC separations, RTX-Wax (polar stationary phase) and RTX-1 (non-polar stationary phase) columns were implemented for the primary and secondary dimensions, respectively, to separate the chemical compound classes (alkanes, cycloalkanes, aromatics, etc.), providing a significant level of chemical compositional information. The GC × GC-TOFMS data were analyzed using partial least squares regression (PLS) chemometric analysis to model and predict advanced distillation curve (ADC) data for ten RP-1 fuels that were previously analyzed using the ADC method. The PLS modeling provides insight into the chemical species that impact the ADC data. The PLS modeling correlates compositional information found in the GC × GC-TOFMS chromatograms of each RP-1 fuel, and their respective ADC, and allows prediction of the ADC for each RP-1 fuel with good precision and accuracy. The root-mean-square error of calibration (RMSEC) ranged from 0.1 to 0.5 °C, and was typically below ∼0.2 °C, for the PLS calibration of the ADC modeling with GC × GC-TOFMS data, indicating a good fit of the model to the calibration data. Likewise, the predictive power of the overall method via PLS modeling was assessed using leave-one-out cross-validation (LOOCV) yielding root-mean-square error of cross-validation (RMSECV) ranging from 1.4 to 2.6 °C, and was typically below ∼2.0 °C, at each % distilled measurement point during the ADC analysis.

9.
Anal Chem ; 86(8): 3973-9, 2014 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-24661185

RESUMO

A novel data reduction and representation method for gas chromatography time-of-flight mass spectrometry (GC-TOFMS) is presented that significantly facilitates separation visualization and analyte peak deconvolution. The method utilizes the rapid mass spectral data collection rate (100 scans/s or greater) of current generation TOFMS detectors. Chromatographic peak maxima (serving as the retention time, tR) above a user specified signal threshold are located, and the chromatographic peak width, W, are determined on a per mass channel (m/z) basis for each analyte peak. The peak W (per m/z) is then plotted against its respective tR (with 10 ms precision) in a two-dimensional (2D) format, producing a cluster of points (i.e., one point per peak W versus tR in the 2D plot). Analysis of GC-TOFMS data by this method produces what is referred to as a two-dimensional mass channel cluster plot (2D m/z cluster plot). We observed that adjacent eluting (even coeluting) peaks in a temperature programmed separation can have their peak W vary as much as ∼10-15%. Hence, the peak W provides useful chemical selectivity when viewed in the 2D m/z cluster plot format. Pairs of overlapped analyte peaks with one-dimensional GC resolution as low as Rs ≈ 0.03 can be visually identified as fully resolved in a 2D m/z cluster plot and readily deconvoluted using chemometrics (i.e., demonstrated using classical least-squares analysis). Using the 2D m/z cluster plot method, the effective peak capacity of one-dimensional GC separations is magnified nearly 40-fold in one-dimensional GC, and potentially ∼100-fold in the context of comparing it to a two-dimensional separation. The method was studied using a 73 component test mixture separated on a 30 m × 250 µm i.d. RTX-5 column with a LECO Pegasus III TOFMS.

10.
Biochem Pharmacol ; 214: 115639, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37290594

RESUMO

Esophageal squamous cell carcinoma (ESCC) is characterized by the development of cancer in the esophageal squamous epithelium through a step-by-step accumulation of genetic, epigenetic, and histopathological alterations. Recent studies have demonstrated that cancer-associated gene mutations exist in histologically normal or precancerous clones of the human esophageal epithelium. However, only a small proportion of such mutant clones will develop ESCC, and most ESCC patients develop only one cancer. This suggests that most of these mutant clones are kept in a histologically normal state by neighboring cells with higher competitive fitness. When some of the mutant cells evade cell competition, they become "super-competitors" and develop into clinical cancer. It is known that human ESCC is composed of a heterogeneous population of cancer cells that interact with and influence their environment and neighbors. During cancer therapy, these cancer cells not only respond to therapeutic agents but also compete with each other. Therefore, competition between ESCC cells within the same ESCC tumor is a constantly dynamic process. However, it remains challenging to fine-tune the competitive fitness of various clones for therapeutic benefits. In this review, we will explore the role of cell competition in carcinogenesis, cancer prevention, and therapy, using NRF2, NOTCH pathway, and TP53 as examples. We believe that cell competition is a research area with promising targets for clinical translation. Manipulating cell competition may help improve the prevention and therapy of ESCC.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Humanos , Carcinoma de Células Escamosas do Esôfago/prevenção & controle , Neoplasias Esofágicas/prevenção & controle , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas/prevenção & controle , Carcinoma de Células Escamosas/genética , Competição entre as Células , Carcinogênese
11.
Am Surg ; 89(12): 6359-6361, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37203324

RESUMO

Rectal small cell carcinoma is a rare and aggressive cancer subtype for which a consensus of optimal treatment has not yet been reached. This cancer presents a difficult surgical problem, and thus, the mainstay of treatment tends to mirror that of small cell carcinoma of the lung (chemotherapy, radiation therapy, and immune modulators). This brief report highlights current treatment options available for this rare and difficult entity. There is a significant need for large-center clinical trials and prospective studies to help determine the best treatment regimen to effectively care for patients with small cell carcinoma of the rectum.


Assuntos
Carcinoma de Células Pequenas , Neoplasias Retais , Humanos , Carcinoma de Células Pequenas/diagnóstico , Carcinoma de Células Pequenas/terapia , Estudos Prospectivos , Reto/patologia , Neoplasias Retais/diagnóstico , Neoplasias Retais/terapia , Neoplasias Retais/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico
12.
Anal Chem ; 84(9): 4167-73, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22448931

RESUMO

Peak capacity production (i.e., peak capacity per separation run time) is substantially improved for gas chromatography-time-of-flight mass spectrometry (GC-TOFMS) and applied to the fast separation of complex samples. The increase in peak capacity production is achieved by selecting appropriate experimental conditions based on theoretical modeling of on-column band broadening, and by reducing the injection pulse width. Modeling to estimate the on-column band broadening from experimental parameters provided insight for the potential of achieving GC separations in the absence of off-column band broadening, i.e., the additional band broadening not due to the on-column separation process. To optimize GC-TOFMS separations collected with a commercial instrumental platform, off-column band broadening from injection and detection needed to be significantly reduced. Specifically for injection, a commercially available thermal modulator is adapted and applied (referred to herein as thermal injection) to provide a narrow injection pulse, while the TOFMS provided a data collection rate of 500 Hz, initially averaged to 100 Hz for data storage. The use of long, relatively narrow open tubular capillary columns and a 30 °C/min programming rate were explored for GC-TOFMS, specifically a 20 m, 100 µm inner diameter (i.d.) capillary column with a 0.4 µm film thickness to benefit column capacity, operated slightly below the optimal average linear gas velocity (at ~2 mL/min, due to the flow rate constraint of the TOFMS). Standard autoinjection with a 1:100 split resulted in an average peak width of ~1.2 s, hence a peak capacity production of 50 peaks/min. Metabolites in the headspace of urine were sampled by solid-phase microextraction (SPME), followed by thermal injection and a ~7 min GC separation (with a ~6 min separation time window), producing ~660 ms peak widths on average, resulting in a total peak capacity of ~550 peaks (at unit resolution) and a peak capacity production of ~90 peaks/min (~2-fold improvement relative to standard autoinjection with the 1:100 split). This total peak capacity production achieved is equivalent to, or greater than, that currently utilized in metabolomics studies using GC/MS, but with much slower separations, on the order of 40 to 60 min, corresponding to a 5-fold or greater GC/MS analysis throughput rate.

13.
Microb Biotechnol ; 15(5): 1542-1549, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34841673

RESUMO

Unlike gaseous C1 feedstocks for acetogenic bacteria, there has been less attention on liquid C1 feedstocks, despite benefits in terms of energy efficiency, mass transfer and integration within existing fermentation infrastructure. Here, we present growth of Eubacterium limosum ATCC8486 using methanol and formate as substrates, finding evidence for the first time of native butanol production. We varied ratios of methanol-to-formate in batch serum bottle fermentations, showing butyrate is the major product (maximum specific rate 220 ± 23 mmol-C gDCW-1 day-1 ). Increasing this ratio showed methanol is the key feedstock driving the product spectrum towards more reduced products, such as butanol (maximum titre 2.0 ± 1.1 mM-C). However, both substrates are required for a high growth rate (maximum 0.19 ± 0.011 h-1 ) and cell density (maximum 1.2 ± 0.043 gDCW l-1 ), with formate being the preferred substrate. In fact, formate and methanol are consumed in two distinct growth phases - growth phase 1, on predominately formate and growth phase 2 on methanol, which must balance. Because the second growth varied according to the first growth on formate, this suggests butanol production is due to overflow metabolism, similar to 2,3-butanediol production in other acetogens. However, further research is required to confirm the butanol production pathway in E. limosum, particularly given, unlike other substrates, methanol likely results in mostly NADH generation, not reduced ferredoxin.


Assuntos
Butanóis , Metanol , 1-Butanol/metabolismo , Butanóis/metabolismo , Eubacterium/metabolismo , Fermentação , Formiatos/metabolismo , Metanol/metabolismo
14.
Infect Prev Pract ; 4(2): 100209, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35295671

RESUMO

In 2019-2020, two subsequent outbreaks caused by phenotypically identical ESBL-producing Enterobacter cloacae and multi-drug-resistant (MDR) Pseudomonas putida were detected in respectively 15 and 9 patients of the haematology-oncology department. Both bacterial species were resistant to piperacillin-tazobactam, used empirically in (neutropenic) sepsis in our hospital, and ciprofloxacin, used prophylactically in selective digestive decontamination for haematology patients. The E. cloacae outbreak was identified in clinical cultures of blood and urine. Despite intensified infection control measures, new cases were found in weekly point-prevalence screening cultures. Environmental samples of sinks and shower drains appeared positive in 18.1%. To diminish the environmental contamination burden, all siphons of sinks were replaced, and disinfection of sinks and shower drains was intensified using chlorine and soda on a daily basis. Replacement of shower drains was not possible. The outbreak of P. putida remained limited to rectal cultures only, and disappeared spontaneously without interventions. During both outbreaks, multiple strains of the incriminated bacterium were found simultaneously (demonstrated by Amplified-Fragment Length Polymorphism and/or Whole-Genome Multi-locus Sequencing Typing) in patients as well as the environment. It was experimentally shown that a biofilm on the toilet edge may act as a source for nosocomial transmission of Gram-negative bacteria. In conclusion, the drainage system of the hospital is an important reservoir of MDR bacteria, threatening the admitted patients. In existing hospitals, biofilms in the drainage systems cannot be removed. Therefore, it is important that in (re)building plans for hospitals a plan for prevention of nosocomial transmission from environment to patients is incorporated.

15.
Anal Chem ; 83(13): 5190-6, 2011 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-21627311

RESUMO

For complex sample analysis, there is a need for multidimensional chromatographic instrumentation to be able to separate more compounds, often in shorter time frames. This has led to the development of comprehensive two-dimensional chromatographic instrumentation, such as comprehensive two-dimensional gas chromatography (GC × GC). Lately, much of the focus in this field has been on decreasing peak widths and, therefore, increasing peak capacity and peak capacity production. All of these advancements make it possible to analyze more compounds in a shorter amount of time, but the data still need to remain quantitative to address the needs of most applications. In this report, the relationship among the modulation ratio (M(R)), peak sampling phase (φ), retention time variation (Δt(R)), and how these parameters relate to quantitative analysis precision via the relative standard deviation (RSD) was studied experimentally using a valve-based GC × GC instrument. A wide range of the number of modulations across the first dimension peak width, that is, a M(R) range from ~1 to 10, was examined through maintaining an average first dimension peak width at the base, (1)w(b) of ~3 s and varying the second dimension separation run time from 300 to 2900 ms. An average RSD of 2.1% was experimentally observed at an average M(R) of 2, with a corresponding peak capacity production of ~1200 peaks/min possible. Below this M(R) the RSD quickly increased. In a long-term study of the quantitative precision at a M(R) of 2.5, using 126 replicate injections of a test mixture spanning ~35 h, the RSD averaged 3.0%. The findings have significant implications for optimizing peak capacity production by allowing the use of the longest second dimension run time, while maintaining quantitative precision.

16.
Water Res ; 201: 117306, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34153823

RESUMO

A circular carbon bioeconomy has potential to halt atmospheric accumulation of greenhouse gases causing climate change and sustainably produce chemical, agricultural and fuel products. Here, we report application of a simplified technoeconomic assessment to critically review two approaches in this space - microbial electrosynthesis and gas fermentation. For microbial electrosynthesis, decoupling of surface-dependant abiotic process for electron delivery from volume-dependant biotic carbon fixation, is shown as the only economically viable strategy to scale-up due to comparatively low biofilm electron consumption rate. This is effectively an electrolyser-assisted gas fermentation system. Targeting high-value products, such as protein for human food consumption is one of the few pathways forward for electrolyser-assisted gas fermentation. Alternatively, gas fermentation of reformed biogas presents an interesting and potentially more sustainable implementation pathway to improve economic viability of chemicals. This critical review suggests linking water treatment resource recovery with gas fermentation is attractive for bioplastics and butanol in terms of competitiveness and market demand.


Assuntos
Dióxido de Carbono , Carbono , Biofilmes , Biocombustíveis , Fermentação , Humanos
17.
Anal Chem ; 82(1): 41-3, 2010 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-19961176

RESUMO

Akin to the standard addition method requiring only a single chromatographic injection, a robust isotope dilution mass spectrometry method is described. The (13)C labeled analyte at known concentration serves as the standard to quantify the unlabeled target analyte. Two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOFMS) provides a combined (12)C and (13)C analyte peak as part of the third order data cube. This combined peak can be isolated from interfering compounds and noise based on the "third order advantage" with parallel factor analysis (PARAFAC). The combined mass spectra are then mathematically resolved using classical least squares (CLS) providing a (12)C/(13)C ratio, thus absolute amounts of (12)C and (13)C. Good agreement between the prepared and determined concentration ratios for test analytes was achieved with further demonstration to real-world samples.

18.
Anal Chem ; 82(2): 689-98, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20014817

RESUMO

In this report we present the feasibility of using analytical and chemometric methodologies to reveal and exploit the chemical impurity profiles from commercial dimethyl methylphosphonate (DMMP) samples to illustrate the type of forensic information that may be obtained from chemical-attack evidence. Using DMMP as a model compound of a toxicant that may be used in a chemical attack, we used comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC x GC/TOF-MS) to detect and identify trace organic impurities in six samples of commercially acquired DMMP. The GC x GC/TOF-MS data was analyzed to produce impurity profiles for all six DMMP samples using 29 analyte impurities. The use of PARAFAC for the mathematical resolution of overlapped GC x GC peaks ensured clean spectra for the identification of many of the detected analytes by spectral library matching. The use of statistical pairwise comparison revealed that there were trace impurities that were quantitatively similar and different among five of the six DMMP samples. Two of the DMMP samples were revealed to have identical impurity profiles by this approach. The use of nonnegative matrix factorization indicated that there were five distinct DMMP sample types as illustrated by the clustering of the multiple DMMP analyses into five distinct clusters in the scores plots. The two indistinguishable DMMP samples were confirmed by their chemical supplier to be from the same bulk source. Sample information from the other chemical suppliers supported the idea that the other four DMMP samples were likely from different bulk sources. These results demonstrate that the matching of synthesized products from the same source is possible using impurity profiling. In addition, the identified impurities common to all six DMMP samples provide strong evidence that basic route information can be obtained from impurity profiles. Finally, impurities that may be unique to the sole bulk manufacturer of DMMP were found in some of the DMMP samples.


Assuntos
Substâncias para a Guerra Química/análise , Ciências Forenses , Cromatografia Gasosa-Espectrometria de Massas/métodos , Estimulantes do Sistema Nervoso Central/análise , Substâncias para a Guerra Química/química , Compostos Organofosforados/análise
19.
Prev Vet Med ; 175: 104881, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31923750

RESUMO

Bovine tuberculosis (bTB) is a chronic, zoonotic, bacterial disease mostly caused by Mycobacterium bovis, which can affect both domestic and wild species. France was officially declared bTB-free in 2001 but faced since 2004 an increase of the prevalence in cattle. Since 2001, bTB has been detected in several wild species: red deer (Cervus elaphus), roe deer (Capreolus capreolus), wild boar (Sus scrofa) and badger (Meles meles). Infected wild species constitute a major threat, because they may contribute to the maintenance of the infection in cattle and prevent eradication. In 2011, a surveillance system, Sylvatub, was implemented nationwide, to monitor the epidemiological status of bTB in mainland France. Our objective in this study was to assess the effectiveness of one of Sylvatub's passive surveillance system components (SSCs), which is based on the visual inspection of hunted animals (wild boars, red and roe deer) throughout mainland France. The following effectiveness criteria were evaluated: individual-level and component group-level positive and negative predictive values, and individual-level and component group-level probabilities of type I error ("false-positive" error) and type II error ("false-negative" error). These criteria were estimated quantitatively, at the scale of the département (a French administrative area of similar size to a county), with a stochastic scenario tree model. Individual negative predictive values were high, whereas individual positive predictive values were poor, whatever the species considered, and the training of hunters did not improve these effectiveness criteria sufficiently. The individual-level probability of type I error was relatively low, but the individual-level probability of type II error was generally high and was therefore an issue. However, increasing the proportion of trained hunters decreased this probability effectively. At group level, the size of the population surveyed had a marked impact on the effectiveness criteria: both the component group-level negative predictive value and the component group-level probability of type II error decreased rapidly with increasing population size. The conclusions drawn from such rationale may directly benefit stakeholders and actors in the field in their day to day practice of the surveillance processes. Thus, the assessment method used in this article presents the advantage of being operational, as well as being applicable to any surveillance system.


Assuntos
Animais Selvagens , Reservatórios de Doenças/veterinária , Monitoramento Epidemiológico/veterinária , Tuberculose Bovina/epidemiologia , Animais , Bovinos , França/epidemiologia , Vigilância da População/métodos , Prevalência , Fatores de Risco , Tuberculose Bovina/microbiologia
20.
J Vet Cardiol ; 29: 11-21, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32348933

RESUMO

INTRODUCTION/OBJECTIVES: Ebstein's anomaly (EA) is a congenital heart disease characterized by apical displacement of the tricuspid valve leaflets in the right ventricle. The objective of this retrospective study was to investigate the signalment, clinical features, echocardiographic findings, and outcome of dogs with EA. ANIMALS, MATERIALS AND METHODS: Medical records of 40 dogs with EA were reviewed. Echocardiographic variables used to assess EA severity in human pediatrics were also evaluated (e.g. displacement index, Celermajer index, Carpentier class, and apex-mitral annulus:apex-tricuspid annulus distance ratio). RESULTS: Labrador retriever was the most commonly recruited breed (24 of the 40 dogs, 60%). Eight of the 40 dogs with EA had hemodynamically compromising concurrent heart (n = 7) or respiratory diseases (n = 1). A right apical systolic heart murmur (median grade = 5/6) was detected in the remaining 32 dogs, without any other clinical sign related to EA in 19 of the 32 dogs (59%). Median (interquartile range) values of the displacement index and Celermajer index were 17.4 mm/m2 (12.0-21.9) and 100% (50-130), respectively. Median time to all-cause death was 74 months, and 72% dogs (95% confidence interval, 50-86%) had not succumbed to cardiac death (CD) 160 months after diagnosis. Univariate analyses showed that the time from diagnosis to CD was associated with the presence of clinical signs, ascites, severe right atrial dilation, palpable thrill, and a Celermajer index ≥100%. DISCUSSION: Right atrial enlargement is significantly associated with decreased survival time of dogs with EA although most may live for years and may not die from CD. CONCLUSIONS: These results support medium to long-term survival for most dogs with EA.


Assuntos
Doenças do Cão/diagnóstico , Anomalia de Ebstein/veterinária , Animais , Doenças do Cão/congênito , Doenças do Cão/diagnóstico por imagem , Doenças do Cão/epidemiologia , Cães , Anomalia de Ebstein/diagnóstico , Anomalia de Ebstein/diagnóstico por imagem , Anomalia de Ebstein/epidemiologia , Ecocardiografia/veterinária , Feminino , Masculino , Estudos Retrospectivos , Análise de Sobrevida , Valva Tricúspide/anormalidades
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