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2.
Clin. transl. oncol. (Print) ; 23(11): 2293-2301, nov. 2021. graf
Artigo em Inglês | IBECS | ID: ibc-223423

RESUMO

Objective The objective of this study was to evaluate the dosimetric impact on hypofractionated prostate radiation therapy of two geometric uncertainty sources: rectum and bladder filling and intrafractional prostate motion.Materials and methodsThis prospective study included 544 images (375 pre-treatment cone-beam CT [CBCT] and 169 post-treatment CBCT) from 15 prostate adenocarcinoma patients. We recalculated the dose on each pre-treatment CBCT once the positioning errors were corrected. We also recalculated two dose distributions on each post-treatment CBCT, either using or not intrafractional motion correction. A correlation analysis was performed between CBCT-based dose and rectum and bladder filling as well as intrafraction prostate displacements.ResultsNo significant differences were found between administered and planned rectal doses. However, we observed an increase in bladder dose due to a lower bladder filling in 66% of treatment fractions. These differences were reduced at the end of the fraction since the lower bladder volume was compensated by the filling during the treatment session. A statistically significant reduction in target volume coverage was observed in 27% of treatment sessions and was correlated with intrafractional prostate motion in sagittal plane > 4 mm.ConclusionsA better control of bladder filling is recommended to minimize the number of fractions in which the bladder volume is lower than planned. Fiducial mark tracking with a displacement threshold of 5 mm in any direction is recommended to ensure that the prescribed dose criteria are met. (AU)


Assuntos
Humanos , Masculino , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/radioterapia , Movimentos dos Órgãos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Reto/efeitos da radiação , Bexiga Urinária/efeitos da radiação , Tomografia Computadorizada de Feixe Cônico , Estudos Prospectivos , Hipofracionamento da Dose de Radiação
3.
Phys Rev Lett ; 127(9): 092301, 2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34506181

RESUMO

We report on the first measurement of charm-strange meson D_{s}^{±} production at midrapidity in Au+Au collisions at sqrt[s_{NN}]=200 GeV from the STAR experiment. The yield ratio between strange (D_{s}^{±}) and nonstrange (D^{0}) open-charm mesons is presented and compared to model calculations. A significant enhancement, relative to a pythia simulation of p+p collisions, is observed in the D_{s}^{±}/D^{0} yield ratio in Au+Au collisions over a large range of collision centralities. Model calculations incorporating abundant strange-quark production in the quark-gluon plasma and coalescence hadronization qualitatively reproduce the data. The transverse-momentum integrated yield ratio of D_{s}^{±}/D^{0} at midrapidity is consistent with a prediction from a statistical hadronization model with the parameters constrained by the yields of light and strange hadrons measured at the same collision energy. These results suggest that the coalescence of charm quarks with strange quarks in the quark-gluon plasma plays an important role in D_{s}^{±}-meson production in heavy-ion collisions.

4.
Phys Rev Lett ; 127(5): 052302, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34397228

RESUMO

The Breit-Wheeler process which produces matter and antimatter from photon collisions is experimentally investigated through the observation of 6085 exclusive electron-positron pairs in ultraperipheral Au+Au collisions at sqrt[s_{NN}]=200 GeV. The measurements reveal a large fourth-order angular modulation of cos4Δϕ=(16.8±2.5)% and smooth invariant mass distribution absent of vector mesons (ϕ, ω, and ρ) at the experimental limit of ≤0.2% of the observed yields. The differential cross section as a function of e^{+}e^{-} pair transverse momentum P_{⊥} peaks at low value with sqrt[⟨P_{⊥}^{2}⟩]=38.1±0.9 MeV and displays a significant centrality dependence. These features are consistent with QED calculations for the collision of linearly polarized photons quantized from the extremely strong electromagnetic fields generated by the highly charged Au nuclei at ultrarelativistic speed. The experimental results have implications for vacuum birefringence and for mapping the magnetic field which is important for emergent QCD phenomena.

5.
Phys Rev Lett ; 126(16): 162301, 2021 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-33961449

RESUMO

Global polarization of Ξ and Ω hyperons has been measured for the first time in Au+Au collisions at sqrt[s_{NN}]=200 GeV. The measurements of the Ξ^{-} and Ξ[over ¯]^{+} hyperon polarization have been performed by two independent methods, via analysis of the angular distribution of the daughter particles in the parity violating weak decay Ξ→Λ+π, as well as by measuring the polarization of the daughter Λ hyperon, polarized via polarization transfer from its parent. The polarization, obtained by combining the results from the two methods and averaged over Ξ^{-} and Ξ[over ¯]^{+}, is measured to be ⟨P_{Ξ}⟩=0.47±0.10(stat)±0.23(syst)% for the collision centrality 20%-80%. The ⟨P_{Ξ}⟩ is found to be slightly larger than the inclusive Λ polarization and in reasonable agreement with a multiphase transport model. The ⟨P_{Ξ}⟩ is found to follow the centrality dependence of the vorticity predicted in the model, increasing toward more peripheral collisions. The global polarization of Ω, ⟨P_{Ω}⟩=1.11±0.87(stat)±1.97(syst)% was obtained by measuring the polarization of daughter Λ in the decay Ω→Λ+K, assuming the polarization transfer factor C_{ΩΛ}=1.

6.
Clin Transl Oncol ; 23(11): 2293-2301, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33913091

RESUMO

OBJECTIVE: The objective of this study was to evaluate the dosimetric impact on hypofractionated prostate radiation therapy of two geometric uncertainty sources: rectum and bladder filling and intrafractional prostate motion. MATERIALS AND METHODS: This prospective study included 544 images (375 pre-treatment cone-beam CT [CBCT] and 169 post-treatment CBCT) from 15 prostate adenocarcinoma patients. We recalculated the dose on each pre-treatment CBCT once the positioning errors were corrected. We also recalculated two dose distributions on each post-treatment CBCT, either using or not intrafractional motion correction. A correlation analysis was performed between CBCT-based dose and rectum and bladder filling as well as intrafraction prostate displacements. RESULTS: No significant differences were found between administered and planned rectal doses. However, we observed an increase in bladder dose due to a lower bladder filling in 66% of treatment fractions. These differences were reduced at the end of the fraction since the lower bladder volume was compensated by the filling during the treatment session. A statistically significant reduction in target volume coverage was observed in 27% of treatment sessions and was correlated with intrafractional prostate motion in sagittal plane > 4 mm. CONCLUSIONS: A better control of bladder filling is recommended to minimize the number of fractions in which the bladder volume is lower than planned. Fiducial mark tracking with a displacement threshold of 5 mm in any direction is recommended to ensure that the prescribed dose criteria are met.


Assuntos
Adenocarcinoma/radioterapia , Movimentos dos Órgãos , Neoplasias da Próstata/radioterapia , Reto/anatomia & histologia , Bexiga Urinária/anatomia & histologia , Adenocarcinoma/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico , Marcadores Fiduciais , Humanos , Masculino , Tamanho do Órgão , Órgãos em Risco/anatomia & histologia , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Estudos Prospectivos , Próstata/diagnóstico por imagem , Neoplasias da Próstata/diagnóstico por imagem , Hipofracionamento da Dose de Radiação , Tolerância a Radiação , Erros de Configuração em Radioterapia , Radioterapia de Intensidade Modulada , Reto/diagnóstico por imagem , Reto/efeitos da radiação , Bexiga Urinária/diagnóstico por imagem , Bexiga Urinária/efeitos da radiação
7.
Phys Med ; 84: 132-140, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33894583

RESUMO

PURPOSE: To use Discrete Cosine Transform to include tumor motion variations on ITV definition of SBRT patients. METHODS: Data from 66 patients was collected. 2D planar fluoroscopy images (FI) were available for 54 patients. Daily CBCT projections (CBCTp) from 29 patients were employed to measure interfraction amplitude variability. Systematic amplitude variations were obtained from 17 patients with data from both FI and CBCTp. Tumor motion curves obtained from FI were characterized with a Cosine model (CM), based on cosine functions to the power of 2, 4 or 6, and DCT. Performance of both models was evaluated by means of R2 coefficient and by comparing their results on Internal Target Volume (ITV) margins against those calculated from original tumor motion curves. Amplitude variations from CBCTp, as well as estimations of baseline shift variations were added to the DCT model to account for their effect on ITV margins. RESULTS: DCT replicated tumor motion curves with a mean R2 values for all patients of 0.86, 0.91 and 0.96 for the lateral (LAT), anterior-posterior (AP) and cranio-caudal (CC) directions respectively. CM yielded worst results, with R2 values of 0.64, 0.61 and 0.74 in the three directions. Interfraction amplitude variation increased ITV margins by a 9%, while baseline shift variability implied a 40% and 80-100% increase for normalized values of baseline shift of 0.2 and 0.4 respectively. CONCLUSIONS: Probability distribution functions of tumor positions can be successfully characterized with DCT. This permits to include tumor motion variablilities obtained from patient population into patient specific ITVs.


Assuntos
Neoplasias Pulmonares , Radiocirurgia , Tomografia Computadorizada Quadridimensional , Humanos , Fígado , Pulmão , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/cirurgia , Movimento (Física) , Planejamento da Radioterapia Assistida por Computador , Respiração
8.
Phys Rev Lett ; 126(9): 092301, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33750161

RESUMO

Nonmonotonic variation with collision energy (sqrt[s_{NN}]) of the moments of the net-baryon number distribution in heavy-ion collisions, related to the correlation length and the susceptibilities of the system, is suggested as a signature for the quantum chromodynamics critical point. We report the first evidence of a nonmonotonic variation in the kurtosis times variance of the net-proton number (proxy for net-baryon number) distribution as a function of sqrt[s_{NN}] with 3.1 σ significance for head-on (central) gold-on-gold (Au+Au) collisions measured solenoidal tracker at Relativistic Heavy Ion Collider. Data in noncentral Au+Au collisions and models of heavy-ion collisions without a critical point show a monotonic variation as a function of sqrt[s_{NN}].

9.
Radiologia (Engl Ed) ; 63(3): 236-244, 2021.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-33461750

RESUMO

Population-based breast cancer screening programs are efficacious in reducing the mortality due to breast cancer. These programs use mammography to screen the women who are invited to participate. Digital mammography makes it possible to develop computer-assisted diagnosis (CAD) systems that promise to reduce the workload of radiologists participating in screening programs. However, various studies have shown that CAD results in a high rate of false positive diagnoses. Systems based on artificial intelligence are being more widely implemented, and studies have shown that these systems have better diagnostic performance than traditional CAD systems. This article explains the fundamentals of artificial intelligence systems and an overview of possible applications of these systems within the framework of breast cancer screening programs.

10.
J Phys Chem A ; 124(22): 4471-4483, 2020 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-32401028

RESUMO

Parahydrogen (pH2) quantum solids are excellent matrix isolation hosts for studying the rovibrational dynamics and nuclear spin conversion (NSC) kinetics of molecules containing indistinguishable nuclei with nonzero spin. The relatively slow NSC kinetics of propyne (CH3CCH) isolated in solid pH2 is employed as a tool to assign the rovibrational spectrum of propyne in the 600-7000 cm-1 region. Detailed analyses of a variety of parallel (ΔK = 0) and perpendicular (ΔK=±1) bands of propyne indicate that the end-over-end rotation of propyne is quenched, but K rotation of the methyl group around the C3 symmetry axis still persists. However, this single-axis K rotation is significantly hindered for propyne trapped in solid pH2 such that the energies of the K rotational states do not obey simple energy-level expressions. The NSC kinetics of propyne follows first-order reversible kinetics with a 287(7) min effective time constant at 1.7 K. Intensity-intensity correlation plots are used to determine the relative line strengths of individual ortho- and para-propyne rovibrational transitions, enabling an independent estimation of the ground vibrational state effective A″ constant of propyne.

11.
Phys Rev Lett ; 124(17): 172301, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32412276

RESUMO

We report on the first measurement of the charmed baryon Λ_{c}^{±} production at midrapidity (|y|<1) in Au+Au collisions at sqrt[s_{NN}]=200 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The Λ_{c}/D^{0} [denoting (Λ_{c}^{+}+Λ_{c}^{-})/(D^{0}+D[over ¯]^{0})] yield ratio is measured to be 1.08±0.16 (stat)±0.26 (sys) in the 0%-20% most central Au+Au collisions for the transverse momentum (p_{T}) range 3

12.
J Appl Microbiol ; 127(1): 68-77, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31013388

RESUMO

AIMS: Candida albicans biofilms are commonly associated with severe oral infections. We previously discovered that a crude extract from the Solidago virgaurea plant (SV extract) was a potent inhibitor of C. albicans biofilm formation. Here, we further investigate the mechanisms underlying C. albicans biofilm inhibition by the SV extract. METHODS AND RESULTS: The SV extract was shown to inhibit laboratory and clinical C. albicans isolates adherence and hyphal transition on inert support and epithelial human cells, without affecting viability and growth of planktonic yeasts. Interestingly, RT-PCR-based experiments demonstrated that some key genes involved in adhesion and hyphal morphological switch (e.g. Hwp1p, Ece1p, Als3p) were strongly down-regulated by the SV extract. Moreover, antimicrobial synergy testing (checkerboard assay) demonstrated that antifungal effects of miconazole, nystatin or a common antiseptic mouthwash were synergistically improved when used in combination with the SV extract. CONCLUSIONS: The SV extract prevents C. albicans biofilm formation through direct inhibition of key adherence and hyphae-associated genes. SIGNIFICANCE AND IMPACT OF THE STUDY: Biofilm is considered as a key virulence factor of C. albicans infection. Our discovery of an inhibitor specifically acting on genes involved in biofilm formation paves the way for the future development of a new class of antifungal product.


Assuntos
Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Extratos Vegetais/farmacologia , Solidago/química , Antifúngicos/farmacologia , Células Cultivadas , Sinergismo Farmacológico , Expressão Gênica/efeitos dos fármacos , Humanos , Hifas/efeitos dos fármacos , Miconazol/farmacologia , Nistatina/farmacologia , Extratos Vegetais/química
13.
Clin Transl Oncol ; 21(5): 607-614, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30328558

RESUMO

BACKGROUND: The objective was to determine the magnitude of the prostate intrafractional motion relative to bony pelvis anatomy, and to evaluate the relationship between this displacement and some clinical and anatomical variables. MATERIALS AND METHODS: The prospective study consisted of 544 images (375 pre-treatment CBCT and 169 post-treatment CBCT) from 15 prostate adenocarcinoma patients that were used for intrafractional prostate motion determination. In addition, two radiation oncologists re-contoured the bladder and rectum on each CBCT according to the patient's anatomy of the day. ANOVA and correlation analysis followed by linear regression analysis were performed to identify clinical or anatomical variables that predict large prostate intrafractional motion. RESULTS: Prostate shift increased in patients with hormone therapy (p ≤ 0.02). The regression analysis showed that patients with large bladder intrafractional filling (p < 0.01) and a large bladder volume difference from planning CT were more likely to experience bigger longitudinal prostate motion (> 3 mm). Recommended bladder size values: anterior-posterior size ≤ 10 cm and anterior-posterior/cranio-caudal ratio ≤ 1.7, both parameters measured in the midsagittal prostate plane, were defined. CONCLUSIONS: The treatment margin should not be reduced for those patients who were treated with hormone therapy and/or whose rectum or bladder was far from complying the preparation protocol conditions.


Assuntos
Movimento , Neoplasias da Próstata/fisiopatologia , Neoplasias da Próstata/radioterapia , Hipofracionamento da Dose de Radiação , Reto/anatomia & histologia , Bexiga Urinária/anatomia & histologia , Idoso , Tomografia Computadorizada de Feixe Cônico/métodos , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Neoplasias da Próstata/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/métodos , Reto/diagnóstico por imagem , Bexiga Urinária/diagnóstico por imagem
14.
Phys Med Biol ; 63(14): 145008, 2018 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-29877195

RESUMO

The aim of this work is to study the radiation doses delivered to a group of patients that underwent a stereotactic breast biopsy (SBB) procedure. Mean glandular doses (MGD) were estimated from the air-kerma measured at the breast surface entrance multiplying by specific conversion coefficients (DgN) that were estimated using Monte Carlo simulations. DgN were calculated for the 0° and ±15° projections used in SBB and for the particular beam quality. Data on 61 patients were collected showing that a typical SBB procedure is composed by ten images. MGD was on average (4 ± 2) mGy with (0.38 ± 0.06) mGy per image. The use of specific conversion coefficients instead of typical DgN for mammography/tomosynthesis yields to obtain MGD values for SBB that are around a 65% lower on average.


Assuntos
Neoplasias da Mama/patologia , Mama/fisiopatologia , Mamografia/métodos , Método de Monte Carlo , Imagens de Fantasmas , Biópsia , Mama/diagnóstico por imagem , Mama/efeitos da radiação , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/radioterapia , Feminino , Humanos , Doses de Radiação
15.
ISBT Sci Ser ; 13(2): 150-157, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-30613210

RESUMO

Background and Objectives: Data on the seroprevalence of viral hepatitis are limited in Haiti; consequently, the epidemiology is poorly described. This study aims to provide a descriptive analysis of hepatitis B virus (HBV) and hepatitis C virus (HCV) seroprevalence of blood donations in Haiti. Materials and Methods: Using Haiti's National Blood Safety Program and Haitian Red Cross reports from 2005 to 2014, we analysed the results of screening tests of donor serum samples to assess HBV and HCV seroprevalence among adults aged 17 to 65 years. Results: A total of 198 758 donor samples were screened from 2005 to 2014, of which 0·56% were positive for antibody to hepatitis C virus (anti-HCV) and 3·80% were positive for hepatitis B surface antigen. Over the 10-year study period, anti-HCV seroprevalence among blood donors increased by 31% from 0.66% to 0.86% (95% CI: 1·01-1·70); however, this trend was not uniform over time, with a significant decrease from 0·66% in 2005 to 0·39% in 2009 (95% CI: 0·43- 0·82) and 0·43% in 2012 (95% CI: 0·50-0·90). Conversely, HBV decreased significantly by 13% from 3·95% in 2005 to 3·42% in 2014 (95% CI: 0·77-0·97), a trend that was also observed in 2012 and 2013. Conclusion: The significant, uniform decrease in HBV seroprevalence in more recent years may represent the positive impact of public health interventions in preventing the transmission of blood-borne infections. More research is needed to understand why the trends in HCV transmission are non-uniform and to investigate the significant increase in more recent years.

16.
Br J Dermatol ; 177(4): 960-966, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27893168

RESUMO

Monitoring of triglycerides for patients on isotretinoin is practised primarily to avoid hypertriglyceridaemia-associated pancreatitis. The aim of this study was to describe clinically the published cases of hypertriglyceride-associated pancreatitis. A comprehensive search strategy using MEDLINE, Embase and grey literature was conducted (1960 to January 2016) to identify all case reports of isotretinoin-associated pancreatitis and all relevant studies of isotretinoin and triglycerides for any indication (≥ 20 patients). Terms related to isotretinoin, triglycerides and pancreatitis were searched with all available synonyms. Any studies that used isotretinoin and mentioned triglycerides or pancreatitis were searched in full text, where available, for cases of pancreatitis. Studies from all countries and published in any language were included, but Korean and Turkish studies could not be analysed. Two authors independently reviewed the publications to determine eligibility, and for data extraction. In total, 125 papers fulfilled the inclusion criteria and were searched for cases of pancreatitis. Eleven papers with 25 cases of pancreatitis associated with isotretinoin were identified; four of these cases were likely due to hypertriglyceridaemia. Three patients had elevated baseline triglycerides, but no monitoring. Pancreatitis occurred 6 and 7 weeks, and 6 months after initiation of therapy. For the fourth patient who was treated for glioblastoma and died, no detailed clinical information was available. Idiosyncratic pancreatitis associated with isotretinoin is the most frequent pancreatitis on isotretinoin, and patients should be warned about it. Hypertriglyceride-associated pancreatitis is an exceedingly rare adverse event of isotretinoin therapy. Our data cannot give a frequency or risk for either adverse event. Based on the clinical information of the patients available, we conclude that for patients without elevated baseline triglycerides, or risk thereof, monitoring of triglycerides during therapy is of little value.


Assuntos
Isotretinoína/efeitos adversos , Pancreatite/induzido quimicamente , Triglicerídeos/metabolismo , Adolescente , Adulto , Idoso , Biomarcadores/metabolismo , Feminino , Humanos , Hipertrigliceridemia/prevenção & controle , Masculino
17.
Phys Med ; 32(6): 767-77, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27180118

RESUMO

The aim of this work was to research and evaluate the performance of three different digital breast tomosynthesis (DBT) systems in the clinical environment (Siemens Mammomat Inspiration, Hologic Selenia Dimensions, and Fujifilm Amulet Innovality). The characterization included the study of the detector, the automatic exposure control, and the resolution of DBT projections and reconstructed planes. The modulation transfer function (MTF) of the DBT projections was measured with a 1mm thick steel edge, showing a strong anisotropy (30-40% lower MTF0.5 frequencies in the tube travel direction). The in-plane MTF0.5, measured with a 25µm tungsten wire, ranges from 1.3 to 1.8lp/mm in the tube-travel direction and between 2.4 and 3.7lp/mm in the chest wall-nipple. In the latter direction, the MTF peak shift is more emphasized for large angular range systems (2.0 versus 1.0lp/mm). In-depth resolution of the planes, via the full width at half maximum (FWHM) from the point spread function of a 25µm tungsten wire, is not only influenced by angular range and yields 1.3-4.6mm among systems. The artifact spread function from 1mm diameter tungsten beads depends mainly on angular range, yielding two tendencies whether large (FWHM is 4.5mm) or small (FWHM is 10mm) angular range is used. DBT delivers per scan a mean glandular dose between 1.4 and 2.7mGy for a 45mm thick polymethyl methacrylate (PMMA) block. In conclusion, we have identified and analysed specific metrics that can be used for quality assurance of DBT systems.


Assuntos
Mamografia/métodos , Artefatos , Humanos , Processamento de Imagem Assistida por Computador , Razão Sinal-Ruído
18.
J Fish Biol ; 85(2): 343-54, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24925695

RESUMO

This study tested whether eutrophication could influence life-history traits of a cyprinid, Chanodichthys erythropterus, in 10 Chinese lakes. Using the von Bertalanffy growth model, the asymptotic length (L∞ ) and the growth performance index (IGRO ) were significantly affected by eutrophication. The gonado-somatic index (IG ) and relative fecundity (FR ) were significantly lower in mesotrophic lakes than in eutrophic and hypertrophic lakes. These results indicate that increasing eutrophication affects the life-history tactics of a freshwater fish.


Assuntos
Cyprinidae/crescimento & desenvolvimento , Meio Ambiente , Eutrofização , Animais , China , Fertilidade , Lagos , Modelos Biológicos , Qualidade da Água
19.
J Chem Phys ; 140(22): 224319, 2014 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-24929400

RESUMO

The photochemistry of glycolaldehyde (GA) upon irradiation at 266 nm is investigated in argon, nitrogen, neon, and para-hydrogen matrices by IR spectroscopy. Isomerization and fragmentation processes are found to compete. The hydrogen-bonded Cis-Cis form of GA is transformed mainly to the open Trans-Trans conformer and to CO and CH3OH fragments and their mixed complexes. Different photo-induced behaviours appear depending on the matrix. In nitrogen, small amounts of Trans-Gauche and Trans-Trans conformers are detected after deposition and grow together upon irradiation. The Trans-Gauche conformer is characterized for the first time. In para-hydrogen due to a weaker cage effect additional H2CO and HCO fragments are seen. Calculations of the potential energy surfaces of S0, S1, and T1 states--to analyse the torsional deformations which are involved in the isomerization process--and a kinetic analysis are presented to investigate the different relaxation pathways of GA. Fragmentation of GA under UV irradiation through the CO+CH3OH molecular channel is a minor process, as in the gas phase.

20.
Arch Pediatr ; 20(12): 1306-9, 2013 Dec.
Artigo em Francês | MEDLINE | ID: mdl-24210985

RESUMO

INTRODUCTION: Aquagenic palmoplantar keratoderma (APK) is a cutaneous phenomenon marked by the formation of edematous, translucent papules and plaques on the palms after water immersion. It can be observed in healthy subjects, but while this dermatosis is little known by practitioners treating these patients, most cases of APK have been described in patients with cystic fibrosis (CF). The primary objective of this study was to evaluate the frequency of APK in a population of children with CF. In addition, the relationship between APK and sex, genotype, pancreatic and pulmonary function, body mass index, and sweat chloride levels was analyzed. METHODS: This study was conducted in 60 children, 27 girls and 33 boys, aged 4 months to 18 years, followed at the CF care center at Angers (France) University Hospital, in whom CF had been confirmed by a positive sweat chloride level greater than 60 mmol. APK was determined by questioning searching for modifications of the palms noticed by the patient or his/her family after immersion in water and a clinical examination searching for the same signs before and after immersion of the right hand in a bucket of lukewarm water for 3 minutes (bucket sign). RESULTS: Forty-seven out of 60 children (78%) had a positive bucket sign. Thirty-eight upon these 47 children had already noticed modifications of the skin on their palms, appearing quickly during the bath and 6 had an edema and an increase in skin folds on the palms of the hands even before immersion of their hand in water. No genotype-phenotype correlations were detected in patients with APK, nor were there associations of APK with other phenotypic features of CF. CONCLUSION: APK is very frequent in patients with CF. It is most probably a consequence of the dysfunction of the CFTR protein. It should be systematically sought in all patients with CF. Its discovery in another context should suggest the diagnosis of CF or a carriage to the heterozygous state of a mutation involved in the disease.


Assuntos
Fibrose Cística/complicações , Fibrose Cística/diagnóstico , Ceratodermia Palmar e Plantar/diagnóstico , Ceratodermia Palmar e Plantar/etiologia , Suor/química , Água/efeitos adversos , Adolescente , Criança , Pré-Escolar , Cloretos/análise , Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Feminino , França , Humanos , Imersão/efeitos adversos , Lactente , Ceratodermia Palmar e Plantar/genética , Masculino , Mutação , Inquéritos e Questionários
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