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1.
MAGMA ; 36(5): 737-747, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36723689

RESUMO

OBJECTIVE: We introduce a non-invasive MR-Acoustic Radiation Force Imaging (ARFI)-based elastography method that provides both the local shear modulus and temperature maps for the monitoring of High Intensity Focused Ultrasound (HIFU) therapy. MATERIALS AND METHODS: To take tissue anisotropy into account, the local shear modulus µ is determined in selected radial directions around the focal spot by fitting the phase profiles to a linear viscoelastic model, including tissue-specific mechanical relaxation time τ. MR-ARFI was evaluated on a calibrated phantom, then applied to the monitoring of HIFU in a gel phantom, ex vivo and in vivo porcine muscle tissue, in parallel with MR-thermometry. RESULTS: As expected, the shear modulus polar maps reflected the isotropy of phantoms and the anisotropy of muscle. In the HIFU monitoring experiments, both the shear modulus polar map and the thermometry map were updated with every pair of MR-ARFI phase images acquired with opposite MR-ARFI-encoding. The shear modulus was found to decrease (phantom and ex vivo) or increase (in vivo) during heating, before remaining steady during the cooling phase. The mechanical relaxation time, estimated pre- and post-HIFU, was found to vary in muscle tissue. DISCUSSION: MR-ARFI allowed for monitoring of viscoelasticity changes around the HIFU focal spot even in anisotropic muscle tissue.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade , Imageamento por Ressonância Magnética , Animais , Suínos , Anisotropia , Imageamento por Ressonância Magnética/métodos , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Espectroscopia de Ressonância Magnética , Acústica
2.
IEEE Open J Eng Med Biol ; 5: 476-484, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38899019

RESUMO

Goal: To evaluate the usability of different technologies designed for a remote assessment of knee osteoarthritis. Methods: We recruited eleven patients affected by mild or moderate knee osteoarthritis, eleven caregivers, and eleven clinicians to assess the following technologies: a wristband for monitoring physical activity, an examination chair for measuring leg extension, a thermal camera for acquiring skin thermographic data, a force balance for measuring center of pressure, an ultrasound imaging system for remote echographic acquisition, a mobile app, and a clinical portal software. Specific questionnaires scoring usability were filled out by patients, caregivers and clinicians. Results: The questionnaires highlighted a good level of usability and user-friendliness for all the technologies, obtaining an average score of 8.7 provided by the patients, 8.8 by the caregivers, and 8.5 by the clinicians, on a scale ranging from 0 to 10. Such average scores were calculated by putting together the scores obtained for the single technologies under evaluation and averaging them. Conclusions: This study demonstrates a high level of acceptability for the tested portable technologies designed for a potentially remote and frequent assessment of knee osteoarthritis.

3.
Phys Med Biol ; 68(3)2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36595333

RESUMO

Objective.The aim of the paper is to propose an all-in-one method based on magnetic resonance-supersonic shear wave imaging (MR-SSI) and proton resonance frequency shift (PRFS) to monitor high intensity focused ultrasound (HIFU) thermal ablations.Approach.Mechanical properties have been shown to be related to tissue damage induced by thermal ablations. Monitoring elasticity in addition to temperature changes may help in ensuring the efficacy and the accuracy of HIFU therapies. For this purpose, an MR-SSI method has been developed where the ultrasonic transducer is used for both mechanical wave generation and thermal ablation. Transient quasi-planar shear waves are generated using the acoustic radiation force, and their propagation is monitored in motion-sensitized phase MR images. Using a single-shot gradient-echo echo-planar-imaging sequence, MR images can be acquired at a sufficiently high temporal resolution to provide an update of PRFS thermometry and MR-SSI elastography maps in real time.Main results.The proposed method was first validated on a calibrated elasticity phantom, in which both the possibility to detect inclusions with different stiffness and repeatability were demonstrated. The standard deviation between the 8 performed measurements was 2% on the background of the phantom and 11%, at most, on the inclusions. A second experiment consisted in performing a HIFU heating in a gelatin phantom. The temperature increase was estimated to be 9 °C and the shear modulus was found to decrease from 2.9 to 1.8 kPa, reflecting the gel softening around the HIFU focus, whereas it remained steady in non-heated areas.Significance.The proposed MR-SSI technique allows monitoring HIFU ablations using thermometry and elastography simultaneously, without the need for an additional external mechanical exciter such as those used in MR elastography.


Assuntos
Técnicas de Imagem por Elasticidade , Tratamento por Ondas de Choque Extracorpóreas , Ablação por Ultrassom Focalizado de Alta Intensidade , Termometria , Técnicas de Imagem por Elasticidade/métodos , Termometria/métodos , Elasticidade , Ultrassom , Imageamento por Ressonância Magnética/métodos , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos
4.
EMBO Mol Med ; 15(4): e15968, 2023 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-36876653

RESUMO

Hematopoietic stem and progenitor cells (HSPCs) can establish a long-lasting microglia-like progeny in the central nervous system of properly myeloablated hosts. We exploited this approach to treat the severe CLN1 neurodegenerative disorder, which is the most aggressive form of neuronal ceroid lipofuscinoses due to palmitoyl-protein thioesterase-1 (PPT1) deficiency. We here provide the first evidence that (i) transplantation of wild-type HSPCs exerts partial but long-lasting mitigation of CLN1 symptoms; (ii) transplantation of HSPCs over-expressing hPPT1 by lentiviral gene transfer enhances the therapeutic benefit of HSPCs transplant, with first demonstration of such a dose-effect benefit for a purely neurodegenerative condition like CLN1 disease; (iii) transplantation of hPPT1 over-expressing HSPCs by a novel intracerebroventricular (ICV) approach is sufficient to transiently ameliorate CLN1-symptoms in the absence of hematopoietic tissue engraftment of the transduced cells; and (iv) combinatorial transplantation of transduced HSPCs intravenously and ICV results in a robust therapeutic benefit, particularly on symptomatic animals. Overall, these findings provide first evidence of efficacy and feasibility of this novel approach to treat CLN1 disease and possibly other neurodegenerative conditions, paving the way for its future clinical application.


Assuntos
Encéfalo , Sistema Nervoso Central , Animais , Camundongos , Modelos Animais de Doenças , Terapia Genética , Células-Tronco Hematopoéticas
5.
Sci Rep ; 12(1): 9095, 2022 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-35641597

RESUMO

Magnetic Resonance (MR) Imaging-guided High Intensity focused Ultrasound (MRgHIFU) is a non-invasive, non-ionizing thermal ablation therapy that is particularly interesting for the palliative or curative treatment of musculoskeletal tumors. We introduce a new modular MRgHIFU device that allows the ultrasound transducer to be positioned precisely and interactively over the body part to be treated. A flexible, MR-compatible supporting structure allows free positioning of the transducer under MRI/optical fusion imaging guidance. The same structure can be rigidified using pneumatic depression, holding the transducer rigidly in place. Targeting accuracy was first evaluated in vitro. The average targeting error of the complete process was found to be equal to 5.4 ± 2.2 mm in terms of focus position, and 4.7° ± 2° in terms of transducer orientation. First-in-man feasibility is demonstrated on a patient suffering from important, uncontrolled pain from a bone metastasis located in the forearm. The 81 × 47 × 34 mm3 lesion was successfully treated using five successive positions of the transducer, under real-time monitoring by MR Thermometry. Significant pain palliation was observed 3 days after the intervention. The system described and characterized in this study is a particularly interesting modular, low-cost MRgHIFU device for musculoskeletal tumor therapy.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade , Neoplasias de Tecido Conjuntivo e de Tecidos Moles , Termometria , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Dor
6.
J Environ Sci Health B ; 46(6): 544-9, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21726154

RESUMO

Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate) was applied with three different formulations on oranges, peaches, tomatoes, wine and table grapes, and its behaviour was evaluated after field treatment. The formulations applied were emulsifiable concentrates (EC), microencapsulates (ME), and wettable granules (WG). The residues were similar in all crops studied in the EC and WG experiments, except peaches with WG treatment, the residue amount was lower than EC values. Tomatoes which were grown in greenhouse showed similar residues in all treatments just after treatment. Wine and table grapes showed different decline curves in the EC experiments ascribable to the different growing technology. Instrumental limit of determination (LOD) and limit of quantification (LOQ) for all matrices were 0.01, and 0.03 mg kg⁻¹, respectively. Repeated treatments showed that Chlorpyrifos can accumulate leading to residue levels at the preharvest interval (PHI) over the maximum residue level (MRL), especially on oranges and peaches. Among the formulates used ME showed the higher risk of residues over the MRL at harvest.


Assuntos
Clorpirifos/análise , Contaminação de Alimentos/análise , Inseticidas/análise , Resíduos de Praguicidas/análise , Biodegradação Ambiental , Cromatografia Gasosa , Citrus sinensis/química , Solanum lycopersicum/química , Prunus/química , Vitis/química , Vinho/análise
7.
J Environ Sci Health B ; 45(6): 493-500, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20574869

RESUMO

Dissipation rates of boscalid [2-chloro-N-(4' -chlorobiphenyl-2-yl)nicotinamide], pyraclostrobin [methyl 2-[1-(4-chlorophenyl) pyrazol-3-yloxymethyl]-N-methoxycarbanilate], lufenuron [(RS)-1-[2,5-dichloro-4-(1,1,2,3,3,3-hexafluoropropoxy)phenyl]-3-(2,6-difluorobenzoyl)urea] and lambda-cyhalothrin [(R)-cyano(3-phenoxyphenyl)methyl (1S,3S)-rel-3-[(1Z)-2-chloro-3,3,3-trifluoro-1-propenyl]-2,2-dimethylcyclopropanecarboxylate] in green beans and spring onions under Egyptian field conditions were studied. Field trials were carried out in 2008 in a Blue Nile farm, located at 70 kilometer (km) from Cairo (Egypt). The pesticides were sprayed at the recommended rate and samples were collected at pre-determined intervals. After treatment (T(0)) the pesticide residues in green beans were 7 times lower than in spring onions. This is due to a different structure of vegetable plant in the two crops. In spring onions, half-life (t(1/2)) of pyraclostrobin and lufenuron was 3.1 days and 9.8 days respectively. At day 14th (T(14)) after treatment boscalid residues were below the Maximum Residue Limit (MRL) (0.34 versus 0.5 mg/kg), pyraclostrobin and lambda -cyhalothrin residues were not detectable (ND), while lufenuron residues were above the MRL (0.06 versus 0.02 mg/kg). In green beans, at T(0), levels of boscalid, lufenuron and lambda -cyhalothrin were below the MRL (0.28 versus 2 mg/kg; ND versus 0.02 mg/kg; 0.06 versus 0.2 mg/kg, respectively) while, after 7 days treatment (T(7)) pyraclostrobin residues were above the MRL (0.03 versus 0.02 mg/kg). However, after 14 days the residue level could go below the MRL (0.02 mg/kg), as observed in spring onions.


Assuntos
Benzamidas/análise , Compostos de Bifenilo/análise , Fabaceae/química , Niacinamida/análogos & derivados , Nitrilas/análise , Cebolas/química , Resíduos de Praguicidas/análise , Piretrinas/análise , Carbamatos , Contaminação de Alimentos/análise , Meia-Vida , Niacinamida/análise , Pirazóis , Estrobilurinas
8.
J Environ Sci Health B ; 44(6): 598-605, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20183068

RESUMO

The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. These experiments were carried out at 1 and 5x the concentration recommended by the manufacturer. In all experiments the deposition of azadirachtin A (AZA-A) was below the maximum residue level (MRL). Even if at the highest dose, AZA-A half-life time calculated as pseudo first order kinetic was 1.2 days in agreement with the recommended preharvest interval (PHI) of 3 days. Experiments with a model system showed that sunlight photodegradation is the main factor influencing the rate of disappearance of AZA-A after greenhouse treatment while tomato epicuticular waxes doubled the photodegradation rate of AZA-A in a commercial formulation.


Assuntos
Inseticidas/metabolismo , Inseticidas/efeitos da radiação , Limoninas/efeitos da radiação , Fotólise/efeitos da radiação , Solanum lycopersicum/metabolismo , Solanum lycopersicum/efeitos da radiação , Luz Solar , Cromatografia Líquida de Alta Pressão , Tecnologia de Alimentos , Meia-Vida , Cinética , Limoneno , Limoninas/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Triterpenos/metabolismo , Triterpenos/efeitos da radiação
9.
J Agric Food Chem ; 56(9): 2939-43, 2008 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-18407653

RESUMO

Neem-based insecticides containing azadirachtin and related azadirachtoids are widely used in agriculture. Here, we report an analytical method for the rapid and accurate quantification of the insecticide azadirachtin A and B and other azadirachtoids such as salannin, nimbin, and their deacetylated analogues on tomatoes and peaches. Azadirachtoids were extracted from fruits and vegetables with acetonitrile. Using high-performance liquid chromatography/electrospray ionization tandem mass spectrometer, azadirachtoids were selectively detected monitoring the multiple reaction transitions of sodium adduct precursor ions. For azadirachtin A, calibration was linear over a working range of 1-1000 microg/L with r > 0.996. The limit of detection and limit of quantification for azadirachtin A were 0.4 and 0.8 microg/kg, respectively. The presence of interfering compounds in the peach and tomato extracts was evaluated and found to be minimal. Because of the linear behavior, it was concluded that the multiple reaction transitions of sodium adduct ions can be used for analytical purposes, that is, for the identification and quantification of azadirachtin A and B and related azadirachtoids in fruit and vegetable extracts at trace levels.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Frutas/química , Inseticidas/análise , Limoninas/análise , Espectrometria de Massas por Ionização por Electrospray/métodos , Verduras/química , Solanum lycopersicum/química , Prunus/química , Controle de Qualidade , Sensibilidade e Especificidade
10.
J Agric Food Chem ; 56(2): 455-60, 2008 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-18163539

RESUMO

The present study investigated the influence of a hot water dip (HWD) for 2 min at 50 degrees C, a standard and effective treatment for postharvest decay control of citrus fruit, on the nutritional and health-related properties of kumquats. The results show that most of the parameters examined, including titratable acidity, soluble solids content, maturity index, glucose, fructose, sucrose, ascorbic acid, dehydroascorbic acid, alpha- and gamma-tocopherols, beta-carotene, zeaxantin, rhoifolin, and antioxidant activity, were not significantly affected by treatment. The levels of beta-cryptoxanthin, narirutin, and total flavonoids increased after HWD, whereas lutein and total phenols decreased. The concentration of the essential oil and the relative percentage of the individual components of the essential oil were not affected by HWD except for the minor compound p-menta-1,5-dien-1-ol, which increased after HWD. After storage, lower levels of glucose, total sugars, beta-carotene, beta-cryptoxanthin and lutein were recorded in HWD fruit. A decrease in antioxidant activity and increases in alpha-tocopherol and total vitamin E were found both in control and HWD fruit. The influence of HWD at 50 degrees C for 2 min on individual nutraceuticals and health-related properties was thus generally low and may depend on storage conditions.


Assuntos
Frutas/química , Temperatura Alta , Rutaceae/química , Água , Carotenoides/análise , Flavonoides/análise , Conservação de Alimentos/métodos , Valor Nutritivo , Óleos Voláteis/análise , Fenóis/análise , Tocoferóis/análise
11.
J Food Prot ; 71(5): 967-72, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18522031

RESUMO

The residue levels of fludioxonil (FLU) were determined in pear cultivars Precoce di Fiorano, Coscia, and Spadona estiva after a 2-min dip in an aqueous mixture of FLU containing 300 or 100 mg/liter of active ingredient at 20 or 50 degrees C and after 12 days at 17 degrees C and 80% relative humidity (simulated shelf life conditions). The accumulation trend of FLU residues was determined in 'Precoce di Fiorano' pears after treatments with 25, 50, 100, or 200 mg/liter of active ingredient at 20 or 50 degrees C for 2 min or at 60 degrees C for 1 min. The efficacy of heat treatments with water and FLU was investigated on artificially inoculated 'Precoce di Fiorano', 'Coscia', and 'Spadona estiva' pears for the control of postharvest blue mold and gray mold caused by Penicillium expansum and Botrytis cinerea, respectively. Treatment with 300 mg/liter FLU at 20 degrees C resulted in residue levels similar to those from treatment with 100 mg/liter FLU at 50 degrees C in 'Coscia' fruit but in significantly lower residues in 'Precoce di Fiorano' and 'Spadona estiva' pears. Post-shelf life residues decreased in all cultivars, especially in 'Spadona estiva' pears treated with 300 mg/liter FLU at 20 degrees C. Residue levels of FLU in 'Precoce di Fiorano' pears treated at 20, 50, or 60 degrees C were correlated with fungicide dosage. When an equal rate was used, treatment at 50 degrees C resulted in a higher and a notably higher FLU deposition than that found under treatment at 60 and 20 degrees C, respectively. The in vitro tests showed that both pathogens were very sensitive to FLU, with MICs averaging 0.05 and 0.1 mg/liter for B. cinerea and P. expansum isolates, respectively. The 50% effective concentration ranged between 0.01 and 0.05 mg/liter for B. cinerea and between 0.05 and 0.1 mg/liter for P. expansum. In the in vivo trials, hot water treatment effectively reduced the incidence of both diseases during the first 4 to 8 days, depending on cultivar, dip temperature, and type of inoculum. However, as the incubation time proceeded, decay reduction was generally lower and the benefit of heat treatments was notably reduced or almost lost. In contrast, all treatments with FLU had a long-lasting effect. Treatments with heated FLU were more effective than those with unheated FLU; reduced concentrations of active ingredient were required to achieve a comparable control of blue and gray mold decay in these pears.


Assuntos
Botrytis/crescimento & desenvolvimento , Dioxóis/farmacologia , Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Conservação de Alimentos/métodos , Penicillium/crescimento & desenvolvimento , Pirróis/farmacologia , Pyrus , Botrytis/efeitos dos fármacos , Contagem de Colônia Microbiana , Relação Dose-Resposta a Droga , Temperatura Alta , Umidade , Penicillium/efeitos dos fármacos , Pyrus/química , Pyrus/microbiologia , Fatores de Tempo
12.
J Econ Entomol ; 101(4): 1075-80, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18767712

RESUMO

Three slow release experimental rotenone formulations were tested to evaluate their effectiveness against Varroa destructor Anderson & Trueman in colonies with sealed brood and to determine whether they left residues in honey and bees wax: we evaluated cardboard strip containing 1 g rotenone and two types of polyvinyl chloride (PVC) strips containing 1 (high-dose) and 0.5 (low-dose) g of rotenone, respectively. In general, the efficacy of the treatments, expressed as percentage of mite mortality, was highly variable in all treatment groups (range, 0-96.8%). The highest effectiveness was obtained with the high-dose-PVC strips, which caused an average percentage of mortality ranging between 47 and 69% in the adult bees and sealed brood, respectively. At the end of the treatment, rotenone residues ranged between 0.03 and 0.06 and 1.5-144.0 mg/kg in honey and wax, respectively. Rotenone residues in wax were still detectable 4 mo after the treatment period, whereas no residues were found in honey. The higher residues content and persistence recorded in wax samples, was probably due to the lipophilic nature of rotenone. A reduction in the amount of adults was recorded for the group treated with high-dose-PVC strips compared with the untreated colonies. Toxicological risks connected with the use of rotenone and the low maximum level recently fixed by European legislation (0.01 mg/kg) suggest that rotenone is not a good candidate for reducing varroa populations in honey bee colonies.


Assuntos
Abelhas/parasitologia , Mel/análise , Inseticidas/administração & dosagem , Ácaros , Resíduos de Praguicidas/análise , Rotenona/administração & dosagem , Ceras/análise , Animais , Abelhas/efeitos dos fármacos , Cromatografia Líquida , Inseticidas/efeitos adversos , Inseticidas/análise , Estágios do Ciclo de Vida/efeitos dos fármacos , Espectrometria de Massas , Rotenona/efeitos adversos , Rotenona/análise
13.
J Agric Food Chem ; 55(17): 7069-74, 2007 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-17658825

RESUMO

An environmental fate study was performed to analyze the effects of soil components on the photochemical behavior of rotenone. Photodegradation experiments were carried out on three types of soil collected in southern Italy, Valenzano (VAL), Turi (TUR), and Conversano (CON), from April to June 2006. Soil thin-layer plates (1 mm thick) were spiked with 1.5 mg/kg of rotenone and exposed under natural conditions of sunlight and temperature. The plates were removed from the sunlight at predetermined intervals of continuous irradiation. Other soil samples, control and sterilized, were kept in the dark to evaluate possible effects of chemical and microbiological degradation during the irradiation experiment. The time for 50% loss of the initially applied rotenone varied from 5 to 7 h, following the order TUR < CON < VAL. In environmental studies, changes in temperature and/or moisture affected the degradation rate and caused deviations from first-order kinetics. The photolysis reaction fit the two compartment or the multiple compartment model pathways better. A fast initial decrease during the first 5 h of rotenone irradiation was followed by a much slower decline, which clearly indicates the rather complex chemical process of rotenone photodegradation on soil surfaces. Also, the degradation was shown to be directly related to the soil concentration of clay and organic matter. Rotenolone (12abeta-hydroxyrotenone) was detected by HPLC/DAD/MS analysis as the only photodegradation byproduct of rotenone in soil thin layers. Results provide additional insights on the rates and the mechanisms of rotenone degradation, aiming to describe more clearly the degradation performance of chemical residues in the environment.


Assuntos
Meio Ambiente , Inseticidas/química , Luz , Rotenona/química , Solo/análise , Itália , Fotoquímica
14.
J Agric Food Chem ; 55(17): 7093-8, 2007 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-17658828

RESUMO

Essential oil (EO) from aerial parts (leaves, juvenile branches, and flowers when present) of Pistacia lentiscus L. growing wild in five localities of Sardinia (Italy) was extracted by steam-distillation (SD) and analyzed by gas chromatography (GC), FID, and GC-ion trap mass spectrometry (ITMS). Samples of P. lentiscus L. were harvested between April and October to study the seasonal chemical variability of the EO. A total of 45 compounds accounting for 97.5-98.4% of the total EO were identified, and the major compounds were alpha-pinene (14.8-22.6%), beta-myrcene (1-19.4%), p-cymene (1.6-16.2%), and terpinen-4-ol (14.2-28.3%). The yields of EO (v/dry w) ranged between 0.09 and 0.32%. Similar content of the major compounds was found in samples from different origins and seasonal variability was also observed. The EOs were tested for their antifungal activity against Aspergillus flavus, Rhizoctonia solani, Penicillium commune, Fusarium oxysporum. Two samples were weakly effective against Aspergillus flavus. Furthermore, terpinenol and alpha-terpineol, two of the major components of EO of Pistacia lentiscus L., totally inhibited the mycelian growth of A. flavus. Quite good antioxidant activity of the EO was also found.


Assuntos
Antioxidantes/farmacologia , Fungicidas Industriais/farmacologia , Óleos Voláteis/química , Pistacia/química , Aspergillus flavus/efeitos dos fármacos , Flores/química , Folhas de Planta/química , Caules de Planta/química , Estações do Ano , Volatilização
15.
J Agric Food Chem ; 55(3): 825-31, 2007 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-17263481

RESUMO

Mature apricots (Prunus armeniaca), nectarines [Prunus persica var. nectarine (Ait.)], and peaches [P. persica (L.) Batsch.] were subjected to a 2 min dip treatment with warm water at 48 degrees C or with fludioxonil (FLU) at 100 mg L-1 and 20 degrees C or at 25 mg L-1 FLU and 48 degrees C and then stored at 5 degrees C and 90-95% relative humidity (RH) for 1 week plus 1 additional week at 18 degrees C and approximately 80% RH. Fruit residue uptake was determined as a function of fungicide concentration, dip temperature, treatment time (only on nectarines), and fruit storage conditions. FLU residue level was closely related to fungicide concentration and treatment temperatures and was dependent on fruit species. FLU residues showed great persistence over both storage and shelf life. Fruit dipping in water at 48 degrees C effectively reduced decay development in cvs. 'May Grand' nectarines and 'Pelese' apricots but was ineffective in cvs. 'Red Top' and 'Sun Crest' nectarines during 7 days of storage compared with nontreated fruit. Decay rates in cvs. 'Glo Haven' peaches and 'Fracasso' apricots were very low in fruit dipped in water at both 20 and 48 degrees C. Fungicide treatments at 20 and 48 degrees C resulted in the total or almost total suppression of decay in all cultivars. During shelf life, fruit became very prone to decay, averaging 25.7-100% depending on the cultivar. Fruit dipping in hot water effectively reduced decay in 'Pelese' and 'Fracasso' apricots, 'Sun Crest' peaches, and 'May Grand' nectarines as compared to control, but was ineffective in 'Glo Haven' and 'Red Top' peaches. Fungicide treatments at 20 degrees C were more effective than hot water in most cultivars. The combination of FLU with water at 48 degrees C further improved the fungicide performance. Indeed, reduced levels (a fourth) of active ingredient were required to achieve a control of decay comparable to that for treatment at 20 degrees C. Residue levels in fruit after treatment with 100 mg L-1 FLU at 20 degrees C or with 25 mg L-1 FLU at 48 degrees C averaged approximately 0.6-2 mg kg-1, which were notably lower than the maximum residue limit (5 mg kg-1) allowed in the United States for stone fruit.


Assuntos
Dioxóis/administração & dosagem , Dioxóis/análise , Conservação de Alimentos/métodos , Frutas/química , Fungicidas Industriais/administração & dosagem , Fungicidas Industriais/análise , Pirróis/administração & dosagem , Pirróis/análise , Resíduos de Drogas/análise , Prunus/química , Fatores de Tempo
16.
J Agric Food Chem ; 55(3): 832-5, 2007 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-17263482

RESUMO

In this paper, pyrethrin levels during a postharvest treatment on stored durum wheat were studied. Two experiments were carried out at single and double the dose recommended by the manufacturer. In all trials, the initial deposition of pyrethrins levels was below the fixed maximum residue level of 3 mg/kg. The fate of pyrethrins in the two experiments was similar, and the total content of pyrethrins remained unchanged for 22 days with a complete dissipation in 8 months. In the single dose experiment, half-life times of pyrethrins I and II were 46 and 72 days, while for the double dose, pyrethrins I and II were 41 and 53 days, respectively.


Assuntos
Manipulação de Alimentos/métodos , Inseticidas , Piretrinas/análise , Piretrinas/química , Triticum/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Resíduos de Praguicidas/análise
17.
J Agric Food Chem ; 55(3): 963-9, 2007 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-17263500

RESUMO

Quince (Cydonia oblonga Miller) fruit aqueous acetone extracts were evaluated. High-performance liquid chromatography-diode array detection and electrospray ionization-mass spectrometry were used for the identification and quantification of the phenolic compounds. The total phenolic content of the pulp and peel parts ranged from 37 to 47 and 105 to 157 mg/100 g of fresh weight, respectively. Chlorogenic acid (5-O-caffeoylquinic acid) was the most abundant phenolic compound in the pulp (37%), whereas rutin (quercetin 3-O-rutinoside) was the main one in the peel (36%). The radical scavenging potential of the extracts was determined and compared with that of synthetic antioxidants. The stronger properties corresponded to those obtained from peel material with a 70-80% inhibitory effect on DPPH radicals. The antimicrobial activity of the extracts against different microorganism strains was also investigated. Quince peel extract was the most active for inhibiting bacteria growth with minimum inhibitory and bactericide concentrations in the range of 102-5 x 103 microg polyphenol/mL. It seems that chlorogenic acid acts in synergism with other components of the extracts to exhibit their total antimicrobial activities.


Assuntos
Anti-Infecciosos/farmacologia , Flavonoides/análise , Flavonoides/farmacologia , Frutas/química , Fenóis/análise , Fenóis/farmacologia , Rosaceae/química , Antioxidantes/farmacologia , Ácido Clorogênico/análise , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polifenóis , Rutina/análise
18.
Int J Med Robot ; 13(4)2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28387448

RESUMO

BACKGROUND: Flexible bendable instruments are key tools for performing surgical endoscopy. Being able to measure the 3D position of such instruments can be useful for various tasks, such as controlling automatically robotized instruments and analyzing motions. METHODS: An automatic method is proposed to infer the 3D pose of a single bending section instrument, using only the images provided by a monocular camera embedded at the tip of the endoscope. The proposed method relies on colored markers attached onto the bending section. The image of the instrument is segmented using a graph-based method and the corners of the markers are extracted by detecting the color transitions along Bézier curves fitted on edge points. These features are accurately located and then used to estimate the 3D pose of the instrument using an adaptive model that takes into account the mechanical play between the instrument and its housing channel. RESULTS: The feature extraction method provides good localization of marker corners with images of the in vivo environment despite sensor saturation due to strong lighting. The RMS error on estimation of the tip position of the instrument for laboratory experiments was 2.1, 1.96, and 3.18 mm in the x, y and z directions, respectively. Qualitative analysis in the case of in vivo images shows the ability to correctly estimate the 3D position of the instrument tip during real motions. CONCLUSIONS: The proposed method provides an automatic and accurate estimation of the 3D position of the tip of a bendable instrument in realistic conditions, where standard approaches fail.


Assuntos
Endoscópios , Endoscopia/instrumentação , Imageamento Tridimensional/métodos , Procedimentos Cirúrgicos Robóticos/instrumentação , Cirurgia Assistida por Computador/instrumentação , Algoritmos , Automação , Endoscopia/métodos , Desenho de Equipamento , Humanos , Movimento (Física) , Imagens de Fantasmas , Reprodutibilidade dos Testes , Procedimentos Cirúrgicos Robóticos/métodos , Robótica , Cirurgia Assistida por Computador/métodos
19.
J Chromatogr A ; 1112(1-2): 232-40, 2006 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-16376912

RESUMO

Anthocyanins in extracts of berries of Myrtus communis, prepared following a typical Sardinia myrtle liqueur recipe, were identified and quantified by HPLC coupled with electrospray/tandem mass spectrometry using, respectively, an ion trap and a triple quadrupole mass analyser. The fragmentation patterns of the anthocyanidins were dependent on the MS technique employed, and differed considerably from those previously reported. The anthocyanin profile of five anthocyanin glucosides and four anthocyanin arabinosides, the latter not previously identified in this specie, was specific for myrtle berry extracts. The quantitative compositions of extracts of myrtle berries derived from different geographical areas in Italy were compared.


Assuntos
Antocianinas/análise , Cromatografia Líquida de Alta Pressão/métodos , Myrtus/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Frutas/química
20.
J Chromatogr A ; 1103(2): 362-7, 2006 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-16387319

RESUMO

Famoxadone is a recent oxazolidinedione fungicide widely used in viticulture and in Integrated Pest Management strategies. In this work, after a simple and fast liquid-liquid extraction (LLE), two new gas chromatographic methods were developed to analyze famoxadone residues in grapes and wines, one with electron-capture detection (GC-ECD) and the other with mass spectrometry (GC-MS). Global uncertainties for validation parameters of both methods were compared. Limits of detection (LODs) were 0.06 and 0.02 mg/L, precision was not above 11.7 and 6.8% and recoveries were, on average, 103%+/-12 and 96%+/-12, respectively, for the GC-ECD and GC-MS methods. Similar expanded uncertainties in the range from 0.25 to 1.00 mg/L were below 35%, with increasing values for lower levels of famoxadone. GC-MS method had a lower LOD and a lower uncertainty if compared with the GC-ECD method.


Assuntos
Cromatografia Gasosa/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Oxazóis/análise , Vitis/química , Vinho/análise , Elétrons , Metacrilatos/análise , Estrobilurinas
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